Fine-scale thermal adaptation in a green turtle nesting population

PubMed Central

Weber, Sam B.; Broderick, Annette C.; Groothuis, Ton G. G.; Ellick, Jacqui; Godley, Brendan J.; Blount, Jonathan D.

2012-01-01

The effect of climate warming on the reproductive success of ectothermic animals is currently a subject of major conservation concern. However, for many threatened species, we still know surprisingly little about the extent of naturally occurring adaptive variation in heat-tolerance. Here, we show that the thermal tolerances of green turtle (Chelonia mydas) embryos in a single, island-breeding population have diverged in response to the contrasting incubation temperatures of nesting beaches just a few kilometres apart. In natural nests and in a common-garden rearing experiment, the offspring of females nesting on a naturally hot (black sand) beach survived better and grew larger at hot incubation temperatures compared with the offspring of females nesting on a cooler (pale sand) beach nearby. These differences were owing to shallower thermal reaction norms in the hot beach population, rather than shifts in thermal optima, and could not be explained by egg-mediated maternal effects. Our results suggest that marine turtle nesting behaviour can drive adaptive differentiation at remarkably fine spatial scales, and have important implications for how we define conservation units for protection. In particular, previous studies may have underestimated the extent of adaptive structuring in marine turtle populations that may significantly affect their capacity to respond to environmental change. PMID:21937495

Potential adverse health effects of persistent organic pollutants on sea turtles: evidences from a cross-sectional study on Cape Verde loggerhead sea turtles.

PubMed

Camacho, María; Luzardo, Octavio P; Boada, Luis D; López Jurado, Luis F; Medina, María; Zumbado, Manuel; Orós, Jorge

2013-08-01

The Cape Verde nesting population of loggerhead sea turtles (Caretta caretta) is the third largest population of this species in the world. For conservation purposes, it is essential to determine how these reptiles respond to different types of anthropogenic contaminants. We evaluated the presence of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) in the plasma of adult nesting loggerheads from Boa Vista Island, Cape Verde, and studied the effects of the contaminants on the health status of the turtles using hematological and biochemical parameters. All turtles had detectable levels of non-dioxin like PCBs, whereas dioxin-like congeners (DL-PCBs) were detected in only 30% of the turtles. Packed cell volume decreased with higher concentrations of PCBs, which suggests that PCB exposure could result in anemia in sea turtles. In addition, a negative association between some OCPs and white blood cells (WBC) and thrombocyte estimate was noted. The DDT-metabolite, p,p'-DDE was negatively correlated with the Na/K ratio and, additionally, a number of correlations between certain PAHs and electrolyte balances were found, which suggest that exposure to these environmental contaminants could affect the kidneys and salt glands in sea turtles. Additionally, several correlations were observed between these environmental pollutants (OCPs and PAHs) and enzyme activity (GGT, ALT, ALP and amylase) and serum protein levels, pointing to the possibility that these contaminants could induce adverse metabolic effects in sea turtles. Our results indicate that anthropogenic pollutants are present in the Cape Verde loggerhead turtle nesting population and could exert negative effects on several health parameters. Because of the importance of this loggerhead nesting population, protective regulations at national and international levels as well as international action are necessary for assuring the conservation of this population. Copyright © 2013 Elsevier B.V. All rights reserved.

Chapter 2. Vulnerability of marine turtles to climate change.

PubMed

Poloczanska, Elvira S; Limpus, Colin J; Hays, Graeme C

2009-01-01

Marine turtles are generally viewed as vulnerable to climate change because of the role that temperature plays in the sex determination of embryos, their long life history, long age-to-maturity and their highly migratory nature. Extant species of marine turtles probably arose during the mid-late Jurassic period (180-150 Mya) so have survived past shifts in climate, including glacial periods and warm events and therefore have some capacity for adaptation. The present-day rates of increase of atmospheric greenhouse gas concentrations, and associated temperature changes, are very rapid; the capacity of marine turtles to adapt to this rapid change may be compromised by their relatively long generation times. We consider the evidence and likely consequences of present-day trends of climate change on marine turtles. Impacts are likely to be complex and may be positive as well as negative. For example, rising sea levels and increased storm intensity will negatively impact turtle nesting beaches; however, extreme storms can also lead to coastal accretion. Alteration of wind patterns and ocean currents will have implications for juveniles and adults in the open ocean. Warming temperatures are likely to impact directly all turtle life stages, such as the sex determination of embryos in the nest and growth rates. Warming of 2 degrees C could potentially result in a large shift in sex ratios towards females at many rookeries, although some populations may be resilient to warming if female biases remain within levels where population success is not impaired. Indirectly, climate change is likely to impact turtles through changes in food availability. The highly migratory nature of turtles and their ability to move considerable distances in short periods of time should increase their resilience to climate change. However, any such resilience of marine turtles to climate change is likely to be severely compromised by other anthropogenic influences. Development of coastlines may threaten nesting beaches and reproductive success, and pollution and eutrophication is threatening important coastal foraging habitats for turtles worldwide. Exploitation and bycatch in other fisheries has seriously reduced marine turtle populations. The synergistic effects of other human-induced stressors may seriously reduce the capacity of some turtle populations to adapt to the current rates of climate change. Conservation recommendations to increase the capacity of marine turtle populations to adapt to climate change include increasing population resilience, for example by the use of turtle exclusion devices in fisheries, protection of nesting beaches from the viewpoints of both conservation and coastal management, and increased international conservation efforts to protect turtles in regions where there is high unregulated or illegal fisheries (including turtle harvesting). Increasing research efforts on the critical knowledge gaps of processes influencing population numbers, such as identifying ocean foraging hotspots or the processes that underlie the initiation of nesting migrations and selection of breeding areas, will inform adaptive management in a changing climate.

Detection of low plasma estradiol concentrations in nesting green turtles (Chelonia mydas) by HPLC/Ms-Ms.

PubMed

Mahmoud, I Y; Alkindi, A Y; Khan, T; Al-Bahry, S N

2011-03-01

In previous studies on nesting green turtles under natural conditions from different geographical regions, 17-β-estradiol (E(2) ) was either undetectable or detected at very low levels. RIA and other related techniques were not sensitive enough to measure low E(2) values in the green turtles. In this study, a sensitive method was used in detecting low hormone concentrations: high performance liquid chromatography with tandem quadruple mass spectrometry (HPLC-MS/MS). Using this technique, estradiol for the first time was detected in nesting green turtles during the peak season (June-October) at Ras Al-Hadd Reserve, Oman. The E(2) values recorded from this study were the highest ever recorded from nesting green turtles in any geographical region, but the levels did not vary significantly throughout different phases of nesting. The presence of E(2) during nesting presumably plays a role in the physiology and behavior of this species. Ras Al-Hadd hosts one of the largest nesting populations of green turtles in the world, and an understanding of their nesting patterns may be of value in conservation and management programs for this endangered species. Copyright © 2011 Wiley-Liss, Inc., A Wiley Company.

Impact of jaguar Panthera onca (Carnivora: Felidae) predation on marine turtle populations in Tortuguero, Caribbean coast of Costa Rica.

PubMed

Arroyo-Arce, Stephanny; Salom-Pérez, Roberto

2015-09-01

Little is known about the effects of jaguars on the population of marine turtles nesting in Tortuguero National Park, Costa Rica. This study assessed jaguar predation impact on three species of marine turtles (Chelonia mydas, Dermochelys coriacea and Eretmochelys imbricata) that nest in Tortuguero beach. Jaguar predation data was obtained by using two methodologies, literature review (historical records prior the year 2005) and weekly surveys along the 29 km stretch of beach during the period 2005-2013. Our results indicated that jaguar predation has increased from one marine turtle in 1981 to 198 in 2013. Jaguars consumed annually an average of 120 (SD = 45) and 2 (SD = 3) green turtles and leatherbacks in Tortuguero beach, respectively. Based on our results we concluded that jaguars do not represent a threat to the population of green turtles that nest in Tortuguero beach, and it is not the main cause for population decline for leatherbacks and hawksbills. Future research should focus on continuing to monitor this predator-prey relationship as well as the factors that influence it so the proper management decisions can be taken.

Non-migratory breeding by isolated green sea turtles (Chelonia mydas) in the Indian Ocean: biological and conservation implications.

PubMed

Whiting, Scott D; Murray, Wendy; Macrae, Ismail; Thorn, Robert; Chongkin, Mohammad; Koch, Andrea U

2008-04-01

Green sea turtles (Chelonia mydas) are renowned for their long-distance migrations but have less fame for short-distance migrations or non-migratory behavior. We present satellite telemetric evidence from Cocos (Keeling) Islands, Indian Ocean for the first predominantly non-migratory green sea turtle (C. mydas) population. The mean migration distance from the nesting beach to the foraging grounds was 35.5 km with a maximum mean transit time of 3.4 days. The behavior of this population has major implications for our general understanding of green turtle behavior and their life cycle and for conservation. Firstly, these results indicate a level of juvenile or adult non-breeding homing behavior from the open ocean to foraging grounds adjacent to their natal nesting beach. Secondly, a non-migratory breeding phase reduces the consumption of reproductive energy utilized, potentially resulting in higher fecundity for this population. Thirdly, the close proximity of the nesting and foraging habitats allows for uniformity in management and conservation strategies rarely possible for wide-ranging green turtle populations.

Non-migratory breeding by isolated green sea turtles ( Chelonia mydas) in the Indian Ocean: biological and conservation implications

NASA Astrophysics Data System (ADS)

Whiting, Scott D.; Murray, Wendy; Macrae, Ismail; Thorn, Robert; Chongkin, Mohammad; Koch, Andrea U.

2008-04-01

Green sea turtles ( Chelonia mydas) are renowned for their long-distance migrations but have less fame for short-distance migrations or non-migratory behavior. We present satellite telemetric evidence from Cocos (Keeling) Islands, Indian Ocean for the first predominantly non-migratory green sea turtle ( C. mydas) population. The mean migration distance from the nesting beach to the foraging grounds was 35.5 km with a maximum mean transit time of 3.4 days. The behavior of this population has major implications for our general understanding of green turtle behavior and their life cycle and for conservation. Firstly, these results indicate a level of juvenile or adult non-breeding homing behavior from the open ocean to foraging grounds adjacent to their natal nesting beach. Secondly, a non-migratory breeding phase reduces the consumption of reproductive energy utilized, potentially resulting in higher fecundity for this population. Thirdly, the close proximity of the nesting and foraging habitats allows for uniformity in management and conservation strategies rarely possible for wide-ranging green turtle populations.

Comparative health assessment of Western Pacific leatherback turtles (Dermochelys coriacea) foraging off the coast of California, 2005-2007.

PubMed

Harris, Heather S; Benson, Scott R; Gilardi, Kirsten V; Poppenga, Robert H; Work, Thierry M; Dutton, Peter H; Mazet, Jonna A K

2011-04-01

Leatherback turtles (Dermochelys coriacea) are critically endangered, primarily threatened by the overharvesting of eggs, fisheries entanglement, and coastal development. The Pacific leatherback population has experienced a catastrophic decline over the past two decades. Leatherbacks foraging off the coast of California are part of a distinct Western Pacific breeding stock that nests on beaches in Indonesia, Papua New Guinea, and the Solomon Islands. Although it has been proposed that the rapid decline of Pacific leatherback turtles is due to increased adult mortality, little is known about the health of this population. Health assessments in leatherbacks have examined females on nesting beaches, which provides valuable biological information, but might have limited applicability to the population as a whole. During September 2005 and 2007, we conducted physical examinations on 19 foraging Pacific leatherback turtles and measured normal physiologic parameters, baseline hematologic and plasma biochemistry values, and exposure to heavy metals (cadmium, lead, and mercury), organochlorine contaminants, and domoic acid. We compared hematologic values of foraging Pacific leatherbacks with their nesting counterparts in Papua New Guinea (n=11) and with other nesting populations in the Eastern Pacific in Costa Rica (n=8) and in the Atlantic in St. Croix (n=12). This study provides the most comprehensive assessment to date of the health status of leatherbacks in the Pacific. We found significant differences in blood values between foraging and nesting leatherbacks, which suggests that health assessment studies conducted only on nesting females might not accurately represent the whole population. The establishment of baseline physiologic data and blood values for healthy foraging leatherback turtles, including males, provides valuable data for long-term health monitoring and comparative studies of this endangered population.

Comparative health assessment of western Pacific leatherback turtles (Dermochelys coriacea) foraging off the coast of California, 2005-2007

USGS Publications Warehouse

Harris, Heather S.; Benson, Scott R.; Gilardi, Kirsten V.; Poppenga, Robert H.; Work, Thierry M.; Dutton, Peter H.; Mazet, Jonna A.K.

2011-01-01

Leatherback turtles (Dermochelys coriacea) are critically endangered, primarily threatened by the overharvesting of eggs, fisheries entanglement, and coastal development. The Pacific leatherback population has experienced a catastrophic decline over the past two decades. Leatherbacks foraging off the coast of California are part of a distinct Western Pacific breeding stock that nests on beaches in Indonesia, Papua New Guinea, and the Solomon Islands. Although it has been proposed that the rapid decline of Pacific leatherback turtles is due to increased adult mortality, little is known about the health of this population. Health assessments in leatherbacks have examined females on nesting beaches, which provides valuable biological information, but might have limited applicability to the population as a whole. During September 2005 and 2007, we conducted physical examinations on 19 foraging Pacific leatherback turtles and measured normal physiologic parameters, baseline hematologic and plasma biochemistry values, and exposure to heavy metals (cadmium, lead, and mercury), organochlorine contaminants, and domoic acid. We compared hematologic values of foraging Pacific leatherbacks with their nesting counterparts in Papua New Guinea (n=11) and with other nesting populations in the Eastern Pacific in Costa Rica (n=8) and in the Atlantic in St. Croix (n=12). This study provides the most comprehensive assessment to date of the health status of leatherbacks in the Pacific. We found significant differences in blood values between foraging and nesting leatherbacks, which suggests that health assessment studies conducted only on nesting females might not accurately represent the whole population. The establishment of baseline physiologic data and blood values for healthy foraging leatherback turtles, including males, provides valuable data for long-term health monitoring and comparative studies of this endangered population.

Spatial requirements of different life-stages of the loggerhead turtle (Caretta caretta) from a distinct population segment in the northern Gulf of Mexico

USGS Publications Warehouse

Lamont, Margaret M.; Putman, Nathan F.; Fujisaki, Ikuko; Hart, Kristen M.

2015-01-01

Many marine species have complex life histories that involve disparate developmental, foraging and reproductive habitats and a holistic assessment of the spatial requirements for different life stages is a challenge that greatly complicates their management. Here, we combined data from oceanographic modeling, nesting surveys, and satellite tracking to examine the spatial requirements of different life stages of Loggerhead Turtles (Caretta caretta) from a distinct population segment in the northern Gulf of Mexico. Our findings indicate that after emerging from nesting beaches in Alabama and Northwest Florida, hatchlings disperse widely and the proportion of turtles following a given route varies substantially through time, with the majority (mean of 74.4%) projected to leave the Gulf of Mexico. Adult females use neritic habitat throughout the northern and eastern Gulf of Mexico both during the inter-nesting phase and as post-nesting foraging areas. Movements and habitat use of juveniles and adult males represent a large gap in our knowledge, but given the hatchling dispersal predictions and tracks of post-nesting females it is likely that some Loggerhead Turtles remain in the Gulf of Mexico throughout their life. More than two-thirds of the Gulf provides potential habitat for at least one life-stage of Loggerhead Turtles. These results demonstrate the importance of the Gulf of Mexico to this Distinct Population Segment of Loggerhead Turtles. It also highlights the benefits of undertaking comprehensive studies of multiple life stages simultaneously: loss of individual habitats have the potential to affect several life stages thereby having long-term consequences to population recovery.

Assessing Nesting Status of Green Turtles, Chelonia Mydas in Perak, Malaysia

PubMed Central

Salleh, Sarahaizad Mohd; Sah, Shahrul Anuar Mohd; Chowdhury, Ahmed Jalal Khan

2018-01-01

The nesting of green turtle (Chelonia mydas) was monitored from 1998 untill 2013 along the beaches of Pasir Panjang, Segari, Perak. The objective of the study is to assess the nesting status of green turtles in Perak, Peninsular Malaysia in terms of total nests, eggs, survival hatchings, and density of visitors. A total number of green turtle nests found for 16 years were 1,019 nests and varied from 10 to 220 nests per year. Meanwhile, the sum of eggs collected for 16 years were 107,820 eggs, and varied from 553 to 20,881 eggs per year. The temporal pattern of nesting indicates year-round nesting in Perak in most years within the 16 years period. The peak season of nesting was estimated to occur between May and June. Survival hatchlings varied from 23.33% (2,071 hatchlings) to 55.03% (5,018 hatchlings) from 1998 to 2013. The density of visitors was not uniformly distributed among the years, and shows a sign of decline especially from 2006 onwards. This publication provides basic knowledge of green turtle nesting population in Perak, and would be helpful in upgrading the conservation program in Malaysia. In future, we hope 1) for an increase in manpower to obtain accurate nesting records along the nesting beaches during nocturnal survey and, 2) to include the breeding biology data such as nest placement, emergence hour, and morphological characteristics of green turtle. PMID:29644022

Resident areas and migrations of female green turtles nesting at Buck Island Reef National Monument, St. Croix, U.S. Virgin Islands

USGS Publications Warehouse

Hart, Kristen M.; Iverson, Autumn; Benscoter, Allison M.; Fujisaki, Ikuko; Cherkiss, Michael S.; Pollock, Clayton; Lundgren, Ian; Hillis-Starr, Zandy

2017-01-01

Satellite tracking in marine turtle studies can reveal much about their spatial use of breeding areas, migration zones, and foraging sites. We assessed spatial habitat-use patterns of 10 adult female green turtles (Chelonia mydas) nesting at Buck Island Reef National Monument, U.S. Virgin Islands (BIRNM) from 2011 – 2014. Turtles ranged in size from 89.0 – 115.9 cm CCL (mean + SD = 106.8 + 7.7 cm). The inter-nesting period across all turtles ranged from 31 July to 4 November, and sizes of the 50% core-use areas during inter-nesting ranged from 4.2 – 19.0 km2. Inter-nesting core-use areas were located up to1.4 km from shore and had bathymetry values ranging from -17.0 to -13.0 m. Seven of the ten turtles remained locally resident after the nesting season. Five turtles (50%) foraged around Buck Island, two foraged around the island of St. Croix, and the other three (30%) made longer-distance migrations to Antigua, St. Kitts & Nevis, and Venezuela. Further, five turtles had foraging centroids within protected areas. Delineating spatial areas and identifying temporal periods of nearshore habitat-use can be useful for natural resource managers with responsibility for overseeing vulnerable habitats and protected marine turtle populations.

Analysis of sugarcane herbicides in marine turtle nesting areas and assessment of risk using in vitro toxicity assays.

PubMed

Allan, Hannah L; van de Merwe, Jason P; Finlayson, Kimberly A; O'Brien, Jake W; Mueller, Jochen F; Leusch, Frederic D L

2017-10-01

Agricultural processes are associated with many different herbicides that can contaminate surrounding environments. In Queensland, Australia, herbicides applied to agricultural crops may pose a threat to valuable coastal habitats including nesting beaches for threatened loggerhead turtles (Caretta caretta). This study 1) measured concentrations of herbicides in the beach sand of Mon Repos, an important marine turtle nesting beach in Australia that is adjacent to significant sugarcane crops, and 2) investigated the toxicity of these herbicides to marine turtles using a cell-based assay. Samples of sand from turtle nest depth and water from surrounding agricultural drains and wetlands were collected during the wet season when herbicide runoff was expected to be the greatest and turtles were nesting. Samples were extracted using solid phase extraction and extracts were analysed using chemical analysis targeting herbicides, as well as bioanalytical techniques (IPAM-assay and loggerhead turtle skin cell cytotoxicity assay). Twenty herbicides were detected in areas between sugarcane crops and the nesting beach, seven of which were also detected in the sand extracts. Herbicides present in the nearby wetland were also detected in the beach sand, indicating potential contamination of the nesting beach via the river outlet as well as ground water. Although herbicides were detected in nesting sand, bioassays using loggerhead turtle skin cells indicated a low risk of acute toxicity at measured environmental concentrations. Further research should investigate potentially more subtle effects, such as endocrine disruption and mixture effects, to better assess the threat that herbicides pose to this population of marine turtles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assignment tests, telemetry and tag-recapture data converge to identify natal origins of leatherback turtles foraging in Atlantic Canadian waters.

PubMed

Stewart, Kelly R; James, Michael C; Roden, Suzanne; Dutton, Peter H

2013-07-01

Investigating migratory connectivity between breeding and foraging areas is critical to effective management and conservation of highly mobile marine taxa, particularly threatened, endangered, or economically important species that cross through regional, national and international boundaries. The leatherback turtle (Dermochelys coriacea, Vandelli 1761) is one such transboundary species that spends time at breeding areas at low latitudes in the northwest Atlantic during spring and summer. From there, they migrate widely throughout the North Atlantic, but many show fidelity to one region off eastern Canada, where critical foraging habitat has been proposed. Our goal was to identify nesting beach origins for turtles foraging here. Using genetics, we identified natal beaches for 288 turtles that were live-captured off the coast of Nova Scotia, Canada. Turtles were sampled (skin or blood) and genotyped using 17 polymorphic microsatellite markers. Results from three assignment testing programs (ONCOR, GeneClass2 and Structure) were compared. Our nesting population reference data set included 1417 individuals from nine Atlantic nesting assemblages. A supplementary data set for 83 foraging turtles traced to nesting beaches using flipper tags and/or PIT tags (n = 72), or inferred from satellite telemetry (n = 11), enabled ground-truthing of the assignments. We first assigned turtles using only genetic information and then used the supplementary recapture information to verify assignments. ONCOR performed best, assigning 64 of the 83 recaptured turtles to natal beaches (77·1%). Turtles assigned to Trinidad (164), French Guiana (72), Costa Rica (44), St. Croix (7), and Florida (1) reflect the relative size of those nesting populations, although none of the turtles were assigned to four other potential source nesting assemblages. Our results demonstrate the utility of genetic approaches for determining source populations of foraging marine animals and include the first identification of natal rookeries of male leatherbacks, identified through satellite telemetry and verified with genetics. This work highlights the importance of long-term monitoring and tagging programmes in nesting and high-use foraging areas. Moreover, it provides a scientific basis for evaluating stock-specific effects of fisheries on migratory marine species, thus identifying where coordinated international recovery efforts may be most effective. © 2013 NOAA ‐ National Marine Fisheries Service. Journal of Animal Ecology © 2013 British Ecological Society.

Hatching success and predation of Bog Turtle (Glyptemys muhlenbergii) eggs in New Jersey and Pennsylvania

USGS Publications Warehouse

Zappalorti, Robert T.; Tutterow, Annalee M.; Pittman, Shannon E.; Lovich, Jeffrey E.

2017-01-01

Nest-site selection by most turtles affects the survival of females and their offspring. Although bog turtles (Glyptemys muhlenbergii) do not typically leave their wetlands for nesting, nest-site selection can impact hatching success and hatchling survival. Between 1974 and 2012, we monitored the fates of 258 bog turtle eggs incubated in the field and 91 eggs incubated under laboratory conditions from 11 different bogs, fens, or wetland complexes in New Jersey and Pennsylvania. Laboratory-incubated eggs exhibited the greatest hatching success (81%), but we did not detect a significant difference in hatching success between nests protected with predator excluder cages (43%) and unprotected nests (33%). However, we found significantly lower predation rates in protected nests, suggesting that while predator excluder cages successfully reduced predation, other environmental factors persisted to reduce egg survival in the field. Natural hatching success was potentially reduced by poor weather conditions, which may have resulted in embryo developmental problems, dehydration, or embryos drowning in the egg. Our results suggest that egg depredation, coupled with embryo developmental problems and infertility, are limiting factors to hatching success in our study populations. Using predator excluder cages to protect bog turtle eggs in the field, or incubating eggs in the laboratory and releasing hatchlings at original nesting areas, may be an effective conservation tool for recovering populations of this federally threatened species.

A Subterranean Camera Trigger for Identifying Predators Excavating Turtle Nests

Treesearch

Thomas J. Maier; Michael N. Marchand; Richard M. DeGraaf; John A. Litvaitis

2002-01-01

Predation is the predominant source of nest mortality for most North American turtle species, including populations that are in decline (Brooks et al. 1992; Congdon et al. 2000). The identification of nest predators---crucial to understanding predator-prey relationships---has been previously accomplished largely by use of techniques that rely on the availability of...

Do roads reduce painted turtle (Chrysemys picta) populations?

PubMed

Dorland, Alexandra; Rytwinski, Trina; Fahrig, Lenore

2014-01-01

Road mortality is thought to be a leading cause of turtle population decline. However, empirical evidence of the direct negative effects of road mortality on turtle population abundance is lacking. The purpose of this study was to provide a strong test of the prediction that roads reduce turtle population abundance. While controlling for potentially confounding variables, we compared relative abundance of painted turtles (Chrysemys picta) in 20 ponds in Eastern Ontario, 10 as close as possible to high traffic roads (Road sites) and 10 as far as possible from any major roads (No Road sites). There was no significant effect of roads on painted turtle relative abundance. Furthermore, our data do not support other predictions of the road mortality hypothesis; we observed neither a higher relative frequency of males to females at Road sites than at No Road sites, nor a lower average body size of turtles at Road than at No Road sites. We speculate that, although roads can cause substantial adult mortality in turtles, other factors, such as release from predation on adults and/or nests close to roads counter the negative effect of road mortality in some populations. We suggest that road mitigation for painted turtles can be limited to locations where turtles are forced to migrate across high traffic roads due, for example, to destruction of local nesting habitat or seasonal drying of ponds. This conclusion should not be extrapolated to other species of turtles, where road mortality could have a larger population-level effect than on painted turtles.

Do Roads Reduce Painted Turtle (Chrysemys picta) Populations?

PubMed Central

Dorland, Alexandra; Rytwinski, Trina; Fahrig, Lenore

2014-01-01

Road mortality is thought to be a leading cause of turtle population decline. However, empirical evidence of the direct negative effects of road mortality on turtle population abundance is lacking. The purpose of this study was to provide a strong test of the prediction that roads reduce turtle population abundance. While controlling for potentially confounding variables, we compared relative abundance of painted turtles (Chrysemys picta) in 20 ponds in Eastern Ontario, 10 as close as possible to high traffic roads (Road sites) and 10 as far as possible from any major roads (No Road sites). There was no significant effect of roads on painted turtle relative abundance. Furthermore, our data do not support other predictions of the road mortality hypothesis; we observed neither a higher relative frequency of males to females at Road sites than at No Road sites, nor a lower average body size of turtles at Road than at No Road sites. We speculate that, although roads can cause substantial adult mortality in turtles, other factors, such as release from predation on adults and/or nests close to roads counter the negative effect of road mortality in some populations. We suggest that road mitigation for painted turtles can be limited to locations where turtles are forced to migrate across high traffic roads due, for example, to destruction of local nesting habitat or seasonal drying of ponds. This conclusion should not be extrapolated to other species of turtles, where road mortality could have a larger population-level effect than on painted turtles. PMID:24858065

Western Pond Turtle Head-starting and Reintroduction; 2002-2003 Progress Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Leuven, Susan; Allen, Harriet; Slavin, Kate

2004-02-01

This report covers the results of the western pond turtle head-starting and reintroduction project for the period of June 2002-September 2003. Wild hatchling western pond turtles from the Columbia River Gorge were reared at the Woodland Park and Oregon Zoos in 2002 and 2003 as part of the recovery effort for this Washington State endangered species. The objective of the program is to reduce losses to introduced predators like bullfrogs and largemouth bass by raising the hatchlings to a size where they are too large to be eaten by most of these predators. In 2002, 27 females from the twomore » Columbia Gorge populations were equipped with transmitters and monitored until they nested. Four more females carrying old transmitters were also monitored; only one of these transmitters lasted through the nesting season. In 2003, 30 females were monitored. Twenty-three of the females monitored in 2002 nested and produced 84 hatchlings. The hatchlings were collected in fall 2002 and reared in captivity at the Woodland Park and Oregon zoos in the head-start program. Twenty-seven of the turtles monitored in 2003 nested. Six of the turtles nested twice, producing a total of 33 nests. The nests will be checked in September and October 2003 for hatchlings. Of 121 head-started juvenile western pond turtles collected in the Columbia Gorge during the 2001 nesting season, 119 were released at three sites in the Columbia Gorge in 2002, and 2 held over for additional growth. Of 86 turtles reared in the head-start program at the Woodland Park and Oregon Zoos fall 2002 through summer 2003, 67 were released at sites in the Columbia Gorge in summer of 2003, and 15 held over for more growth. Fifty-nine juveniles were released at Pierce National Wildlife Refuge in July 2002, and 51 released there in July 2003. Sixteen of those released in 2002 and 16 released in 2003 were instrumented with radio transmitters and monitored for varying amounts of time for survival and habitat use between the time of release and August 2003, together with juveniles from the 2001 release which were monitored from June 2001 through August 2003, and juveniles from the 2000 release which were monitored from August 2000 through August 2003. The number of functioning transmitters varied due to transmitter failures and detachments, and availability of replacement transmitters, as well as opportunities to recapture turtles. By August 15, 2003, a total of 39 turtles were being monitored: 6 from the 2000 release, 8 from the 2001 release, 10 from the 2002 release, and 15 from the 2003 release. During the 2002 field season trapping effort, 280 turtles were captured in the Columbia Gorge, including 236 previously head-started turtles. During the 2003 trapping season, 349 turtles were captured in the Columbia Gorge; 304 of these had been head-started. These recaptures, together with confirmed nesting by head-start females and visual re-sightings, indicate the program is succeeding in boosting juvenile recruitment to increase the populations. Records were also collected on 160 individual painted turtles captured in 2002 and 189 painted turtles captured in 2003 during trapping efforts at Pierce NWR, to gather baseline information on this native population. Eight female painted turtles were monitored by telemetry during the 2002 nesting season; 4 nests were recorded for these animals, plus 35 nests located incidentally. Preferred habitat for nesting was identified based on the telemetry results, to be considered in anticipating future turtle habitat needs and in management planning at Pierce NWR. Bonneville Power Administration (BPA) funding supported activities in the Columbia River Gorge from June 2002 through September 2003.« less

Nesting fidelity and molecular evidence for natal homing in the freshwater turtle, Graptemys kohnii

PubMed Central

Freedberg, Steven; Ewert, Michael A; Ridenhour, Benjamin J; Neiman, Maurine; Nelson, Craig E

2005-01-01

Numerous studies of sea turtle nesting ecology have revealed that females exhibit natal homing, whereby they imprint on the nesting area from which they hatch and subsequently return there to nest as adults. Because freshwater turtles comprise the majority of reptiles known to display environmental sex determination (ESD), the study of natal homing in this group may shed light on recent evolutionary models of sex allocation that are predicated on natal homing in reptiles with ESD. We examined natal homing in Graptemys kohnii, a freshwater turtle with ESD, using mitochondrial sequencing, microsatellite genotyping and mark and recapture of 290 nesting females. Females showed high fidelity to nesting areas, even after being transplanted several kilometres away. A Mantel test revealed significant genetic isolation by distance with respect to nesting locations (r=0.147; p<0.05), suggesting that related females nest in close proximity to one another. The patterns of fidelity and genotype distributions are consistent with homing at a scale that may affect population sex ratios. PMID:16006324

The Impact of Turtle Excluder Devices and Fisheries Closures on Loggerhead and Kemp's Ridley Strandings in the Western Gulf of Mexico

USGS Publications Warehouse

Lewison, R.L.; Crowder, L.B.; Shaver, D.J.

2003-01-01

The Sea Turtle Stranding and Salvage Network has been monitoring turtle strandings for more than 20 years in the United States. High numbers of strandings in the early to mid-1980s prompted regulations to require turtle excluder devices (TEDs) on shrimping vessels (trawlers). Following year-round TED implementation in 1991, however, stranding levels in the Gulf of Mexico increased. We evaluated the efficacy of TEDs and other management actions (e.g., fisheries closures) on loggerhead (Caretta caretta) and Kemp's ridley (Lepidochelys kempii) turtle populations by analyzing a long-term, stranding data set from the western Gulf of Mexico. Our analyses suggest that both sea turtle population growth and shrimping activity have contributed to the observed increase in strandings. Compliance with regulations requiring turtle excluder devices was a significant factor in accounting for annual stranding variability: low compliance was correlated with high levels of strandings. Our projections suggest that improved compliance with TED regulations will reduce strandings to levels that, in conjunction with other protective measures, should promote population recoveries for loggerhead and Kemp's ridley turtles. Local, seasonal fisheries closures, concurrent with TED enforcement, could reduce strandings to even lower levels. A seasonal closure adjacent to a recently established Kemp's ridley nesting beach may also reduce mortality of nesting adults and thus promote long-term population persistence by fostering the establishment of a robust secondary nesting site.

Contamination in marine turtle (Dermochelys coriaca) egg shells of Playon de Mexiquillo, Michoacan, Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vazquez, G.F.; Reyes, M.C.; Fenandez, G.

Concern for the decreasing population sizes of marine turtles around the world is growing. Potential contamination within habitats of marine turtles, and human activities, such as poaching, modification of nesting sites, and capture of adult turtles, may be responsible for their decreasing populations. Little is known about the baseline levels and physiological effects of environmental contaminants on marine turtle populations. Responding to this concern, the Mexican government has designated areas along the Mexican coastline to preserve marine turtle nesting habitats. {open_quotes}Playon de Mexiquillo{close_quotes}, Michocan, Mexico is one of the coastal preservation areas located near the mouth of Rio la Manzanillamore » which flows between Sierra Madre del Sur and the Pacific Ocean. Samples of seawater, sand, and marine turtle egg (Dermochelys Coriaca) shells were collected monthly from October, 1992-March, 1993. Contaminants investigated were oil and grease, and metals (cadmium, copper, zinc, nickel, and lead). Seawater samples were collected where the turtles lay eggs in the preservation area and sand samples were taken from the area surrounding the eggs. 12 refs., 1 fig., 4 tabs.« less

Regional Management Units for Marine Turtles: A Novel Framework for Prioritizing Conservation and Research across Multiple Scales

PubMed Central

Wallace, Bryan P.; DiMatteo, Andrew D.; Hurley, Brendan J.; Finkbeiner, Elena M.; Bolten, Alan B.; Chaloupka, Milani Y.; Hutchinson, Brian J.; Abreu-Grobois, F. Alberto; Amorocho, Diego; Bjorndal, Karen A.; Bourjea, Jerome; Bowen, Brian W.; Dueñas, Raquel Briseño; Casale, Paolo; Choudhury, B. C.; Costa, Alice; Dutton, Peter H.; Fallabrino, Alejandro; Girard, Alexandre; Girondot, Marc; Godfrey, Matthew H.; Hamann, Mark; López-Mendilaharsu, Milagros; Marcovaldi, Maria Angela; Mortimer, Jeanne A.; Musick, John A.; Nel, Ronel; Pilcher, Nicolas J.; Seminoff, Jeffrey A.; Troëng, Sebastian; Witherington, Blair; Mast, Roderic B.

2010-01-01

Background Resolving threats to widely distributed marine megafauna requires definition of the geographic distributions of both the threats as well as the population unit(s) of interest. In turn, because individual threats can operate on varying spatial scales, their impacts can affect different segments of a population of the same species. Therefore, integration of multiple tools and techniques — including site-based monitoring, genetic analyses, mark-recapture studies and telemetry — can facilitate robust definitions of population segments at multiple biological and spatial scales to address different management and research challenges. Methodology/Principal Findings To address these issues for marine turtles, we collated all available studies on marine turtle biogeography, including nesting sites, population abundances and trends, population genetics, and satellite telemetry. We georeferenced this information to generate separate layers for nesting sites, genetic stocks, and core distributions of population segments of all marine turtle species. We then spatially integrated this information from fine- to coarse-spatial scales to develop nested envelope models, or Regional Management Units (RMUs), for marine turtles globally. Conclusions/Significance The RMU framework is a solution to the challenge of how to organize marine turtles into units of protection above the level of nesting populations, but below the level of species, within regional entities that might be on independent evolutionary trajectories. Among many potential applications, RMUs provide a framework for identifying data gaps, assessing high diversity areas for multiple species and genetic stocks, and evaluating conservation status of marine turtles. Furthermore, RMUs allow for identification of geographic barriers to gene flow, and can provide valuable guidance to marine spatial planning initiatives that integrate spatial distributions of protected species and human activities. In addition, the RMU framework — including maps and supporting metadata — will be an iterative, user-driven tool made publicly available in an online application for comments, improvements, download and analysis. PMID:21253007

Predicting bycatch hotspots for endangered leatherback turtles on longlines in the Pacific Ocean.

PubMed

Roe, John H; Morreale, Stephen J; Paladino, Frank V; Shillinger, George L; Benson, Scott R; Eckert, Scott A; Bailey, Helen; Tomillo, Pilar Santidrián; Bograd, Steven J; Eguchi, Tomoharu; Dutton, Peter H; Seminoff, Jeffrey A; Block, Barbara A; Spotila, James R

2014-02-22

Fisheries bycatch is a critical source of mortality for rapidly declining populations of leatherback turtles, Dermochelys coriacea. We integrated use-intensity distributions for 135 satellite-tracked adult turtles with longline fishing effort to estimate predicted bycatch risk over space and time in the Pacific Ocean. Areas of predicted bycatch risk did not overlap for eastern and western Pacific nesting populations, warranting their consideration as distinct management units with respect to fisheries bycatch. For western Pacific nesting populations, we identified several areas of high risk in the north and central Pacific, but greatest risk was adjacent to primary nesting beaches in tropical seas of Indo-Pacific islands, largely confined to several exclusive economic zones under the jurisdiction of national authorities. For eastern Pacific nesting populations, we identified moderate risk associated with migrations to nesting beaches, but the greatest risk was in the South Pacific Gyre, a broad pelagic zone outside national waters where management is currently lacking and may prove difficult to implement. Efforts should focus on these predicted hotspots to develop more targeted management approaches to alleviate leatherback bycatch.

Predicting bycatch hotspots for endangered leatherback turtles on longlines in the Pacific Ocean

PubMed Central

Roe, John H.; Morreale, Stephen J.; Paladino, Frank V.; Shillinger, George L.; Benson, Scott R.; Eckert, Scott A.; Bailey, Helen; Tomillo, Pilar Santidrián; Bograd, Steven J.; Eguchi, Tomoharu; Dutton, Peter H.; Seminoff, Jeffrey A.; Block, Barbara A.; Spotila, James R.

2014-01-01

Fisheries bycatch is a critical source of mortality for rapidly declining populations of leatherback turtles, Dermochelys coriacea. We integrated use-intensity distributions for 135 satellite-tracked adult turtles with longline fishing effort to estimate predicted bycatch risk over space and time in the Pacific Ocean. Areas of predicted bycatch risk did not overlap for eastern and western Pacific nesting populations, warranting their consideration as distinct management units with respect to fisheries bycatch. For western Pacific nesting populations, we identified several areas of high risk in the north and central Pacific, but greatest risk was adjacent to primary nesting beaches in tropical seas of Indo-Pacific islands, largely confined to several exclusive economic zones under the jurisdiction of national authorities. For eastern Pacific nesting populations, we identified moderate risk associated with migrations to nesting beaches, but the greatest risk was in the South Pacific Gyre, a broad pelagic zone outside national waters where management is currently lacking and may prove difficult to implement. Efforts should focus on these predicted hotspots to develop more targeted management approaches to alleviate leatherback bycatch. PMID:24403331

Marine turtles are not fussy nesters: a novel test of small-scale nest site selection using structure from motion beach terrain information

PubMed Central

Leon, Javier X.; Gilby, Ben L.; Olds, Andrew D.; Schlacher, Thomas A.

2017-01-01

Background Nest selection is widely regarded as a key process determining the fitness of individuals and viability of animal populations. For marine turtles that nest on beaches, this is particularly pivotal as the nesting environment can significantly control reproductive success.The aim of this study was to identify the environmental attributes of beaches (i.e., morphology, vegetation, urbanisation) that may be associated with successful oviposition in green and loggerhead turtle nests. Methods We quantified the proximity of turtle nests (and surrounding beach locations) to urban areas, measured their exposure to artificial light, and used ultra-high resolution (cm-scale) digital surface models derived from Structure-from-Motion (SfM) algorithms, to characterise geomorphic and vegetation features of beaches on the Sunshine Coast, eastern Australia. Results At small spatial scales (i.e., <100 m), we found no evidence that turtles selected nest sites based on a particular suite of environmental attributes (i.e., the attributes of nest sites were not consistently different from those of surrounding beach locations). Nest sites were, however, typically characterised by occurring close to vegetation, on parts of the shore where the beach- and dune-face was concave and not highly rugged, and in areas with moderate exposure to artificial light. Conclusion This study used a novel empirical approach to identify the attributes of turtle nest sites from a broader ‘envelope’ of environmental nest traits, and is the first step towards optimizing conservation actions to mitigate, at the local scale, present and emerging human impacts on turtle nesting beaches. PMID:28070454

Who are the important predators of sea turtle nests at Wreck Rock beach?

PubMed Central

Booth, David T.

2017-01-01

Excessive sea turtle nest predation is a problem for conservation management of sea turtle populations. This study assessed predation on nests of the endangered loggerhead sea turtle (Caretta caretta) at Wreck Rock beach adjacent to Deepwater National Park in Southeast Queensland, Australia after a control program for feral foxes was instigated. The presence of predators on the nesting dune was evaluated by tracking plots (2 × 1 m) every 100 m along the dune front. There were 21 (2014–2015) and 41 (2015–2016) plots established along the dune, and these were monitored for predator tracks daily over three consecutive months in both nesting seasons. Predator activities at nests were also recorded by the presence of tracks on top of nests until hatchlings emerged. In addition, camera traps were set to record the predator activity around selected nests. The tracks of the fox (Vulpes vulpes) and goanna (Varanus spp) were found on tracking plots. Tracking plots, nest tracks and camera traps indicated goanna abundance varied strongly between years. Goannas were widely distributed along the beach and had a Passive Activity Index (PAI) (0.31 in 2014–2015 and 0.16 in 2015–2016) approximately seven times higher than that of foxes (PAI 0.04 in 2014–2015 and 0.02 in 2015–2016). Five hundred and twenty goanna nest visitation events were recorded by tracks but no fox tracks were found at turtle nests. Camera trap data indicated that yellow-spotted goannas (Varanus panoptes) appeared at loggerhead turtle nests more frequently than lace monitors (V. varius) did, and further that lace monitors only predated nests previously opened by yellow-spotted goannas. No foxes were recorded at nests with camera traps. This study suggests that large male yellow-spotted goannas are the major predator of sea turtle nests at the Wreck Rock beach nesting aggregation and that goanna activity varies between years. PMID:28674666

Stormy oceans are associated with declines in sea turtle hatching.

PubMed

Van Houtan, Kyle S; Bass, Oron L

2007-08-07

Many sea turtle populations are below 10% of their pre-Columbian numbers [1-4]. Though historic and systematic over-exploitation is the principal cause of these declines, sea turtles face similar threats today. Adults and juveniles are actively hunted and commercial fisheries catch them incidentally. Nesting suffers from beach development, egg poaching and the poaching of nesting females. Accompanying these familiar hazards is the largely unknown consequences of recent climate change. Here we report monitoring surveys from the Dry Tortugas National Park (DTNP, 24.64N 82.86W), Florida, and show that hurricanes and other storm events are an additional and increasing threat to loggerhead turtle (Caretta caretta) and green sea turtle (Chelonia mydas) nesting. Both species are listed by the US Endangered Species Act and the IUCN considers them 'endangered'.

Mercury and selenium concentrations in leatherback sea turtles (Dermochelys coriacea): population comparisons, implications for reproductive success, hazard quotients and directions for future research.

PubMed

Perrault, Justin R; Miller, Debra L; Garner, Jeanne; Wyneken, Jeanette

2013-10-01

Leatherback sea turtles (Dermochelys coriacea) are long-distance migrants that travel thousands of km from foraging grounds to breeding and nesting grounds. These extensive journeys are fueled by ingestion of an estimated 300-400 kg of prey/d and likely result in exposure to high concentrations of environmental toxicants (e.g., mercury compounds). Increased bodily concentrations of mercury and its compounds in nesting female turtles may have detrimental effects on reproductive success. Leatherbacks have relatively low reproductive success compared with other sea turtles (global average hatching success ~50-60%). To assess toxicants and necessary nutrients as factors affecting leatherback turtle reproductive success at Sandy Point National Wildlife Refuge (SPNWR), St. Croix, U.S. Virgin Islands, we collected blood from nesting female leatherbacks and tissues from their hatchlings (blood from live turtles, liver and yolk sac from dead turtles). We compared the concentrations in those tissues to hatching and emergence success. We found that on SPNWR, hatching and emergence success were more closely related to seasonal factors than to total mercury and selenium concentrations in both nesting females and hatchlings. Selenium concentrations of nesting females were positively correlated with those of their hatchlings. Mercury and selenium in the liver of hatchlings were positively correlated with one another. Turtles with greater remigration intervals tended to have higher blood selenium concentrations, suggesting that selenium accumulates in leatherbacks through time. Through hazard quotients, we found evidence that selenium may be at or above concentrations that may cause physiologic harm to hatchlings. We also found evidence that population level differences exist for these trace elements. The concentrations of mercury and selenium established in this manuscript form a baseline for future toxicant studies. Copyright © 2013 Elsevier B.V. All rights reserved.

Influence of incubation temperature on sea turtle hatchling quality.

PubMed

Booth, David T

2017-09-01

Since the 1980s it has been known that incubation temperature influences the sex ratio of sea turtle hatchlings emerging from their nests, and there has been much speculation on how global climate change might threaten sea turtle populations by raising nest temperatures and causing highly female-biased hatchling sex ratios. More recently, studies have indicated that incubation temperature can also influence the size and locomotor performance of sea turtle hatchlings. Here I review recent studies that have explored the influence of incubation temperature on sea turtle hatchling quality in terms of hatchling morphology and locomotor performance. I also discuss the likely underlying mechanisms responsible for incubation temperature-induced differences in hatchling locomotor performance, and how an increase in nest temperature associated with global warming might affect recruitment of sea turtle hatchlings. © 2017 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Are thermal barriers "higher" in deep sea turtle nests?

PubMed

Santidrián Tomillo, Pilar; Fonseca, Luis; Paladino, Frank V; Spotila, James R; Oro, Daniel

2017-01-01

Thermal tolerances are affected by the range of temperatures that species encounter in their habitat. Daniel Janzen hypothesized in his "Why mountain passes are higher in the tropics" that temperature gradients were effective barriers to animal movements where climatic uniformity was high. Sea turtles bury their eggs providing some thermal stability that varies with depth. We assessed the relationship between thermal uniformity and thermal tolerance in nests of three species of sea turtles. We considered that barriers were "high" when small thermal changes had comparatively large effects and "low" when the effects were small. Mean temperature was lower and fluctuated less in species that dig deeper nests. Thermal barriers were comparatively "higher" in leatherback turtle (Dermochelys coriacea) nests, which were the deepest, as embryo mortality increased at lower "high" temperatures than in olive ridley (Lepidochelys olivacea) and green turtle (Chelonia mydas) nests. Sea turtles have temperature-dependent sex determination (TSD) and embryo mortality increased as temperature approached the upper end of the transitional range of temperatures (TRT) that produces both sexes (temperature producing 100% female offspring) in leatherback and olive ridley turtles. As thermal barriers are "higher" in some species than in others, the effects of climate warming on embryo mortality is likely to vary among sea turtles. Population resilience to climate warming may also depend on the balance between temperatures that produce female offspring and those that reduce embryo survival.

Hawksbill satellite-tracking case study: Implications for remigration interval and population estimates

USGS Publications Warehouse

Sartain-Iverson, Autumn R.; Hart, Kristen M.; Fujisaki, Ikuko; Cherkiss, Michael S.; Pollock, Clayton; Lundgren, Ian; Hillis-Starr, Zandy

2016-01-01

Hawksbill sea turtles (Eretmochelys imbricata) are circumtropically distributed and listed as Critically Endangered by the IUCN (Meylan & Donnelly 1999; NMFS & USFWS 1993). To aid in population recovery and protection, the Hawksbill Recovery Plan identified the need to determine demographic information for hawksbills, such as distribution, abundance, seasonal movements, foraging areas (sections 121 and 2211), growth rates, and survivorship (section 2213, NMFS & USFWS 1993). Mark-recapture analyses are helpful in estimating demographic parameters and have been used for hawksbills throughout the Caribbean (e.g., Richardson et al. 1999; Velez-Zuazo et al. 2008); integral to these studies are recaptures at the nesting site as well as remigration interval estimates (Hays 2000). Estimates of remigration intervals (the duration between nesting seasons) are critical to marine turtle population estimates and measures of nesting success (Hays 2000; Richardson et al. 1999). Although hawksbills in the Caribbean generally show natal philopatry and nesting-site fidelity (Bass et al. 1996; Bowen et al. 2007), exceptions to this have been observed for hawksbills and other marine turtles (Bowen & Karl 2007; Diamond 1976; Esteban et al. 2015; Hart et al. 2013). This flexibility in choosing a nesting beach could therefore affect the apparent remigration interval and subsequently, region-wide population counts.

Population genetics and phylogeography of sea turtles.

PubMed

Bowen, B W; Karl, S A

2007-12-01

The seven species of sea turtles occupy a diversity of niches, and have a history tracing back over 100 million years, yet all share basic life-history features, including exceptional navigation skills and periodic migrations from feeding to breeding habitats. Here, we review the biogeographic, behavioural, and ecological factors that shape the distribution of genetic diversity in sea turtles. Natal homing, wherein turtles return to their region of origin for mating and nesting, has been demonstrated with mtDNA sequences. These maternally inherited markers show strong population structure among nesting colonies while nuclear loci reveal a contrasting pattern of male-mediated gene flow, a phenomenon termed 'complex population structure'. Mixed-stock analyses indicate that multiple nesting colonies can contribute to feeding aggregates, such that exploitation of turtles in these habitats can reduce breeding populations across the region. The mtDNA data also demonstrate migrations across entire ocean basins, some of the longest movements of marine vertebrates. Multiple paternity occurs at reported rates of 0-100%, and can vary by as much as 9-100% within species. Hybridization in almost every combination among members of the Cheloniidae has been documented but the frequency and ultimate ramifications of hybridization are not clear. The global phylogeography of sea turtles reveals a gradient based on habitat preference and thermal regime. The cold-tolerant leatherback turtle (Dermochelys coriacea) shows no evolutionary partitions between Indo-Pacific and Atlantic populations, while the tropical green (Chelonia mydas), hawksbill (Eretmochelys imbricata), and ridleys (Lepidochelys olivacea vs. L. kempi) have ancient separations between oceans. Ridleys and loggerhead (Caretta caretta) also show more recent colonization between ocean basins, probably mediated by warm-water gyres that occasionally traverse the frigid upwelling zone in southern Africa. These rare events may be sufficient to prevent allopatric speciation under contemporary geographic and climatic conditions. Genetic studies have advanced our understanding of marine turtle biology and evolution, but significant gaps persist and provide challenges for the next generation of sea turtle geneticists.

Oxidative stress biomarkers and organochlorine pesticides in nesting female hawksbill turtles Eretmochelys imbricata from Mexican coast (Punta Xen, Mexico).

PubMed

Salvarani, Patricia I; Vieira, Luis R; Ku-Peralta, Wiliam; Morgado, Fernando; Osten, Jaime Rendón-von

2018-06-06

Because of their vulnerable population status, assessing exposure levels and impacts of toxicants on the health status of Gulf of Mexico marine turtle populations is essential, and this study was aimed to obtain baseline information on oxidative stress indicators in hawksbill sea turtle (Eretmochelys imbricata). In order to evaluate the health status of sea turtles and the effect of organochlorine compounds (OC) in the southern part of the Gulf of Mexico, we searched for relationships between carapace size and the activity of antioxidant enzymes in the blood of the hawksbill sea turtle. The level of oxidative stress biomarkers such as the enzymes catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione S-transferase (GST), and acetylcholinesterase (Ache) in the hawksbill sea turtle was analysed during nesting season in the years 2014-2015 at Punta Xen (Campeche, Mexico). The results of this study provide insight into data of antioxidant enzyme activities in relation to contaminant OCPs in hawksbill sea turtles and the possible health impacts of contaminant in sea turtles.

Movements and diving behavior of internesting green turtles along Pacific Costa Rica.

PubMed

Blanco, Gabriela S; Morreale, Stephen J; Seminoff, Jeffrey A; Paladino, Frank V; Piedra, Rotney; Spotila, James R

2013-09-01

Using satellite transmitters, we determined the internesting movements, spatial ecology and diving behavior of East Pacific green turtles (Chelonia mydas) nesting on Nombre de Jesús and Zapotillal beaches along the Pacific coast of northwestern Costa Rica. Kernel density analysis indicated that turtles spent most of their time in a particularly small area in the vicinity of the nesting beaches (50% utilization distribution was an area of 3 km(2) ). Minimum daily distance traveled during a 12 day internesting period was 4.6 ± 3.5 km. Dives were short and primarily occupied the upper 10 m of the water column. Turtles spent most of their time resting at the surface and conducting U-dives (ranging from 60 to 81% of the total tracking time involved in those activities). Turtles showed a strong diel pattern, U-dives mainly took place during the day and turtles spent a large amount of time resting at the surface at night. The lack of long-distance movements demonstrated that this area was heavily utilized by turtles during the nesting season and, therefore, was a crucial location for conservation of this highly endangered green turtle population. The unique behavior of these turtles in resting at the surface at night might make them particularly vulnerable to fishing activities near the nesting beaches. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

Are thermal barriers "higher" in deep sea turtle nests?

PubMed Central

Santidrián Tomillo, Pilar; Fonseca, Luis; Paladino, Frank V.; Spotila, James R.; Oro, Daniel

2017-01-01

Thermal tolerances are affected by the range of temperatures that species encounter in their habitat. Daniel Janzen hypothesized in his “Why mountain passes are higher in the tropics” that temperature gradients were effective barriers to animal movements where climatic uniformity was high. Sea turtles bury their eggs providing some thermal stability that varies with depth. We assessed the relationship between thermal uniformity and thermal tolerance in nests of three species of sea turtles. We considered that barriers were “high” when small thermal changes had comparatively large effects and “low” when the effects were small. Mean temperature was lower and fluctuated less in species that dig deeper nests. Thermal barriers were comparatively “higher” in leatherback turtle (Dermochelys coriacea) nests, which were the deepest, as embryo mortality increased at lower “high” temperatures than in olive ridley (Lepidochelys olivacea) and green turtle (Chelonia mydas) nests. Sea turtles have temperature-dependent sex determination (TSD) and embryo mortality increased as temperature approached the upper end of the transitional range of temperatures (TRT) that produces both sexes (temperature producing 100% female offspring) in leatherback and olive ridley turtles. As thermal barriers are “higher” in some species than in others, the effects of climate warming on embryo mortality is likely to vary among sea turtles. Population resilience to climate warming may also depend on the balance between temperatures that produce female offspring and those that reduce embryo survival. PMID:28545092

Phenotypic plasticity of nest timing in a post-glacial landscape: how do reptiles adapt to seasonal time constraints?

PubMed

Edge, Christopher B; Rollinson, Njal; Brooks, Ronald J; Congdon, Justin D; Iverson, John B; Janzen, Fredric J; Litzgus, Jacqueline D

2017-02-01

Life histories evolve in response to constraints on the time available for growth and development. Nesting date and its plasticity in response to spring temperature may therefore be important components of fitness in oviparous ectotherms near their northern range limit, as reproducing early provides more time for embryos to complete development before winter. We used data collected over several decades to compare air temperature and nest date plasticity in populations of painted turtles and snapping turtles from a relatively warm environment (southeastern Michigan) near the southern extent of the last glacial maximum to a relatively cool environment (central Ontario) near the northern extent of post-glacial recolonization. For painted turtles, population-level differences in reaction norm elevation for two phenological traits were consistent with adaptation to time constraints, but no differences in reaction norm slopes were observed. For snapping turtle populations, the difference in reaction norm elevation for a single phenological trait was in the opposite direction of what was expected under adaptation to time constraints, and no difference in reaction norm slope was observed. Finally, among-individual variation in individual plasticity for nesting date was detected only in the northern population of snapping turtles, suggesting that reaction norms are less canalized in this northern population. Overall, we observed evidence of phenological adaptation, and possibly maladaptation, to time constraints in long-lived reptiles. Where present, (mal)adaptation occurred by virtue of differences in reaction norm elevation, not reaction norm slope. Glacial history, generation time, and genetic constraint may all play an important role in the evolution of phenological timing and its plasticity in long-lived reptiles. © 2016 by the Ecological Society of America.

Predaceous ants, beach replenishment, and nest placement by sea turtles.

PubMed

Wetterer, James K; Wood, Lawrence D; Johnson, Chris; Krahe, Holly; Fitchett, Stephanie

2007-10-01

Ants known for attacking and killing hatchling birds and reptiles include the red imported fire ant (Solenopsis invicta Buren), tropical fire ant [Solenopsis geminata (Fabr.)], and little fire ant [Wasmannia auropunctata (Roger)]. We tested whether sea turtle nest placement influenced exposure to predaceous ants. In 2000 and 2001, we surveyed ants along a Florida beach where green turtles (Chelonia mydas L.), leatherbacks (Dermochelys coriacea Vandelli), and loggerheads (Caretta caretta L.) nest. Part of the beach was artificially replenished between our two surveys. As a result, mean beach width experienced by nesting turtles differed greatly between the two nesting seasons. We surveyed 1,548 sea turtle nests (2000: 909 nests; 2001: 639 nests) and found 22 ant species. S. invicta was by far the most common species (on 431 nests); S. geminata and W. auropunctata were uncommon (on 3 and 16 nests, respectively). In 2000, 62.5% of nests had ants present (35.9% with S. invicta), but in 2001, only 30.5% of the nests had ants present (16.4% with S. invicta). Turtle nests closer to dune vegetation had significantly greater exposure to ants. Differences in ant presence on turtle nests between years and among turtle species were closely related to differences in nest placement relative to dune vegetation. Beach replenishment significantly lowered exposure of nests to ants because on the wider beaches turtles nested farther from the dune vegetation. Selective pressures on nesting sea turtles are altered both by the presence of predaceous ants and the practice of beach replenishment.

Historical versus Contemporary Climate Forcing on the Annual Nesting Variability of Loggerhead Sea Turtles in the Northwest Atlantic Ocean

PubMed Central

Arendt, Michael D.; Schwenter, Jeffrey A.; Witherington, Blair E.; Meylan, Anne B.; Saba, Vincent S.

2013-01-01

A recent analysis suggested that historical climate forcing on the oceanic habitat of neonate sea turtles explained two-thirds of interannual variability in contemporary loggerhead (Caretta caretta) sea turtle nest counts in Florida, where nearly 90% of all nesting by this species in the Northwest Atlantic Ocean occurs. Here, we show that associations between annual nest counts and climate conditions decades prior to nest counts and those conditions one year prior to nest counts were not significantly different. Examination of annual nest count and climate data revealed that statistical artifacts influenced the reported 31-year lag association with nest counts. The projected importance of age 31 neophytes to annual nest counts between 2020 and 2043 was modeled using observed nest counts between 1989 and 2012. Assuming consistent survival rates among cohorts for a 5% population growth trajectory and that one third of the mature female population nests annually, the 41% decline in annual nest counts observed during 1998–2007 was not projected for 2029–2038. This finding suggests that annual nest count trends are more influenced by remigrants than neophytes. Projections under the 5% population growth scenario also suggest that the Peninsular Recovery Unit could attain the demographic recovery criteria of 106,100 annual nests by 2027 if nest counts in 2019 are at least comparable to 2012. Because the first year of life represents only 4% of the time elapsed through age 31, cumulative survival at sea across decades explains most cohort variability, and thus, remigrant population size. Pursuant to the U.S. Endangered Species Act, staggered implementation of protection measures for all loggerhead life stages has taken place since the 1970s. We suggest that the 1998–2007 nesting decline represented a lagged perturbation response to historical anthropogenic impacts, and that subsequent nest count increases since 2008 reflect a potential recovery response. PMID:24339901

Historical versus contemporary climate forcing on the annual nesting variability of loggerhead sea turtles in the Northwest Atlantic Ocean.

PubMed

Arendt, Michael D; Schwenter, Jeffrey A; Witherington, Blair E; Meylan, Anne B; Saba, Vincent S

2013-01-01

A recent analysis suggested that historical climate forcing on the oceanic habitat of neonate sea turtles explained two-thirds of interannual variability in contemporary loggerhead (Caretta caretta) sea turtle nest counts in Florida, where nearly 90% of all nesting by this species in the Northwest Atlantic Ocean occurs. Here, we show that associations between annual nest counts and climate conditions decades prior to nest counts and those conditions one year prior to nest counts were not significantly different. Examination of annual nest count and climate data revealed that statistical artifacts influenced the reported 31-year lag association with nest counts. The projected importance of age 31 neophytes to annual nest counts between 2020 and 2043 was modeled using observed nest counts between 1989 and 2012. Assuming consistent survival rates among cohorts for a 5% population growth trajectory and that one third of the mature female population nests annually, the 41% decline in annual nest counts observed during 1998-2007 was not projected for 2029-2038. This finding suggests that annual nest count trends are more influenced by remigrants than neophytes. Projections under the 5% population growth scenario also suggest that the Peninsular Recovery Unit could attain the demographic recovery criteria of 106,100 annual nests by 2027 if nest counts in 2019 are at least comparable to 2012. Because the first year of life represents only 4% of the time elapsed through age 31, cumulative survival at sea across decades explains most cohort variability, and thus, remigrant population size. Pursuant to the U.S. Endangered Species Act, staggered implementation of protection measures for all loggerhead life stages has taken place since the 1970s. We suggest that the 1998-2007 nesting decline represented a lagged perturbation response to historical anthropogenic impacts, and that subsequent nest count increases since 2008 reflect a potential recovery response.

Bottom-up and climatic forcing on the worldwide population of leatherback turtles.

PubMed

Saba, Vincent S; Spotila, James R; Chavez, Francisco P; Musick, John A

2008-05-01

Nesting populations of leatherback turtles (Dermochelys coriacea) in the Atlantic and western Indian Oceans are increasing or stable while those in the Pacific are declining. It has been suggested that leatherbacks in the eastern Pacific may be resource limited due to environmental variability derived from the El Niño Southern Oscillation (ENSO), but this has yet to be tested. Here we explored bottom-up forcing and the responding reproductive output of nesting leatherbacks worldwide. We achieved this through an extensive review of leatherback nesting and migration data and by analyzing the spatial, temporal, and quantitative nature of resources as indicated by net primary production at post-nesting female migration and foraging areas. Leatherbacks in the eastern Pacific were the smallest in body size and had the lowest reproductive output due to less productive and inconsistent resources within their migration and foraging areas. This derived from natural interannual and multidecadal climate variability together with an influence of anthropogenic climate warming that is possibly affecting these natural cycles. The reproductive output of leatherbacks in the Atlantic and western Indian Oceans was nearly twice that of turtles in the eastern Pacific. The inconsistent nature of the Pacific Ocean may also render western Pacific leatherbacks susceptible to a more variable reproductive output; however, it appears that egg harvesting on nesting beaches is their major threat. We suggest that the eastern Pacific leatherback population is more sensitive to anthropogenic mortality due to recruitment rates that are lower and more variable, thus accounting for much of the population differences compared to Atlantic and western Indian turtles.

Breeding sex ratio and population size of loggerhead turtles from Southwestern Florida.

PubMed

Lasala, Jacob A; Hughes, Colin R; Wyneken, Jeanette

2018-01-01

Species that display temperature-dependent sex determination are at risk as a result of increasing global temperatures. For marine turtles, high incubation temperatures can skew sex ratios towards females. There are concerns that temperature increases may result in highly female-biased offspring sex ratios, which would drive a future sex ratio skew. Studying the sex ratios of adults in the ocean is logistically very difficult because individuals are widely distributed and males are inaccessible because they remain in the ocean. Breeding sex ratios (BSR) are sought as a functional alternative to study adult sex ratios. One way to examine BSR is to determine the number of males that contribute to nests. Our goal was to evaluate the BSR for loggerhead turtles (Caretta caretta) nesting along the eastern Gulf of Mexico in Florida, from 2013-2015, encompassing three nesting seasons. We genotyped 64 nesting females (approximately 28% of all turtles nesting at that time) and up to 20 hatchlings from their nests (n = 989) using 7 polymorphic microsatellite markers. We identified multiple paternal contributions in 70% of the nests analyzed and 126 individual males. The breeding sex ratio was approximately 1 female for every 2.5 males. We did not find repeat males in any of our nests. The sex ratio and lack of repeating males was surprising because of female-biased primary sex ratios. We hypothesize that females mate offshore of their nesting beaches as well as en route. We recommend further comparisons of subsequent nesting events and of other beaches as it is imperative to establish baseline breeding sex ratios to understand how growing populations behave before extreme environmental effects are evident.

Breeding sex ratio and population size of loggerhead turtles from Southwestern Florida

PubMed Central

Hughes, Colin R.; Wyneken, Jeanette

2018-01-01

Species that display temperature-dependent sex determination are at risk as a result of increasing global temperatures. For marine turtles, high incubation temperatures can skew sex ratios towards females. There are concerns that temperature increases may result in highly female-biased offspring sex ratios, which would drive a future sex ratio skew. Studying the sex ratios of adults in the ocean is logistically very difficult because individuals are widely distributed and males are inaccessible because they remain in the ocean. Breeding sex ratios (BSR) are sought as a functional alternative to study adult sex ratios. One way to examine BSR is to determine the number of males that contribute to nests. Our goal was to evaluate the BSR for loggerhead turtles (Caretta caretta) nesting along the eastern Gulf of Mexico in Florida, from 2013–2015, encompassing three nesting seasons. We genotyped 64 nesting females (approximately 28% of all turtles nesting at that time) and up to 20 hatchlings from their nests (n = 989) using 7 polymorphic microsatellite markers. We identified multiple paternal contributions in 70% of the nests analyzed and 126 individual males. The breeding sex ratio was approximately 1 female for every 2.5 males. We did not find repeat males in any of our nests. The sex ratio and lack of repeating males was surprising because of female-biased primary sex ratios. We hypothesize that females mate offshore of their nesting beaches as well as en route. We recommend further comparisons of subsequent nesting events and of other beaches as it is imperative to establish baseline breeding sex ratios to understand how growing populations behave before extreme environmental effects are evident. PMID:29370223

Breeding sex ratios in adult leatherback turtles (Dermochelys coriacea) may compensate for female-biased hatchling sex ratios.

PubMed

Stewart, Kelly R; Dutton, Peter H

2014-01-01

For vertebrates with temperature-dependent sex determination, primary (or hatchling) sex ratios are often skewed, an issue of particular relevance to concerns over effects of climate change on populations. However, the ratio of breeding males to females, or the operational sex ratio (OSR), is important to understand because it has consequences for population demographics and determines the capacity of a species to persist. The OSR also affects mating behaviors and mate choice, depending on the more abundant sex. For sea turtles, hatchling and juvenile sex ratios are generally female-biased, and with warming nesting beach temperatures, there is concern that populations may become feminized. Our purpose was to evaluate the breeding sex ratio for leatherback turtles at a nesting beach in St. Croix, USVI. In 2010, we sampled nesting females and later sampled their hatchlings as they emerged from nests. Total genomic DNA was extracted and all individuals were genotyped using 6 polymorphic microsatellite markers. We genotyped 662 hatchlings from 58 females, matching 55 females conclusively to their nests. Of the 55, 42 females mated with one male each, 9 mated with 2 males each and 4 mated with at least 3 males each, for a multiple paternity rate of 23.6%. Using GERUD1.0, we reconstructed parental genotypes, identifying 47 different males and 46 females for an estimated breeding sex ratio of 1.02 males for every female. Thus we demonstrate that there are as many actively breeding males as females in this population. Concerns about female-biased adult sex ratios may be premature, and mate choice or competition may play more of a role in sea turtle reproduction than previously thought. We recommend monitoring breeding sex ratios in the future to allow the integration of this demographic parameter in population models.

The ethological trap: functional and numerical responses of highly efficient invasive predators driving prey extinctions.

PubMed

Spencer, Ricky-John; Van Dyke, James U; Thompson, Michael B

2016-10-01

Ecological traps are threats to organisms, and exist in a range of biological systems. A subset of ecological trap theory is the "ethological trap," whereby behaviors canalized by past natural selection become traps when environments change rapidly. Invasive predators are major threats to imperiled species and their ability to exploit canalized behaviors of naive prey is particularly important for the establishment of the predator and the decline of the native prey. Our study uses ecological theory to demonstrate that invasive predator controls require shifts in management priorities. Total predation rate (i.e., total response) is the product of both the functional response and numerical response of predators to prey. Functional responses are the changes in the rate of prey consumption by individual predators, relative to prey abundance. Numerical responses are the aggregative rates of prey consumption by all predators relative to prey density, which change with predator density via reproduction or migration, in response to changes in prey density. Traditional invasive predator management methods focus on reducing predator populations, and thus manage for numerical responses. These management efforts fail to manage for functional responses, and may not eliminate impacts of highly efficient individual predators. We explore this problem by modeling the impacts of functional and numerical responses of invasive foxes depredating imperiled Australian turtle nests. Foxes exhibit exceptionally efficient functional responses. A single fox can destroy >95% of turtle nests in a nesting area, which eliminates juvenile recruitment. In this case, the ethological trap is the "Arribada" nesting strategy, an emergent behavior whereby most turtles in a population nest simultaneously in the same nesting grounds. Our models show that Arribada nesting events do not oversaturate foxes, and small numbers of foxes depredate all of the nests in a given Arribada. Widely scattering nests may reduce fox predation rates, but the long generation times of turtles combined with their rapid recent decline suggests that evolutionary responses in nesting strategy may be unlikely. Our study demonstrates that reducing populations of highly efficient invasive predators is insufficient for preserving native prey species. Instead, management must reduce individual predator efficiency, independent of reducing predator population size. © 2016 by the Ecological Society of America.

Projected response of an endangered marine turtle population to climate change

NASA Astrophysics Data System (ADS)

Saba, Vincent S.; Stock, Charles A.; Spotila, James R.; Paladino, Frank V.; Tomillo, Pilar Santidrián

2012-11-01

Assessing the potential impacts of climate change on individual species and populations is essential for the stewardship of ecosystems and biodiversity. Critically endangered leatherback turtles in the eastern Pacific Ocean are excellent candidates for such an assessment because their sensitivity to contemporary climate variability has been substantially studied. If incidental fisheries mortality is eliminated, this population still faces the challenge of recovery in a rapidly changing climate. Here we combined an Earth system model, climate model projections assessed by the Intergovernmental Panel on Climate Change and a population dynamics model to estimate a 7% per decade decline in the Costa Rica nesting population over the twenty-first century. Whereas changes in ocean conditions had a small effect on the population, the ~2.5°C warming of the nesting beach was the primary driver of the decline through reduced hatching success and hatchling emergence rate. Hatchling sex ratio did not substantially change. Adjusting nesting phenology or changing nesting sites may not entirely prevent the decline, but could offset the decline rate. However, if future observations show a long-term decline in hatching success and emergence rate, anthropogenic climate mitigation of nests (for example, shading, irrigation) may be able to preserve the nesting population.

Sea Turtle Navigation and the Detection of Geomagnetic Field Features

NASA Astrophysics Data System (ADS)

Lohmann, Kenneth J.; Lohmann, Catherine M. F.

The lives of sea turtles consist of a continuous series of migrations. As hatchlings, the turtles swim from their natal beaches into the open sea, often taking refuge in circular current systems (gyres) that serve as moving, open-ocean nursery grounds. The juveniles of many populations subsequently take up residence in coastal feeding areas that are located hundreds or thousands of kilometres from the beaches on which the turtles hatched; some juveniles also migrate between summer and winter habitats. As adults, turtles periodically leave their feeding grounds and migrate to breeding and nesting regions, after which many return to their own specific feeding sites. The itinerant lifestyle characteristic of most sea turtle species is thus inextricably linked to an ability to orient and navigate accurately across large expanses of seemingly featureless ocean.In some sea turtle populations, migratory performance reaches extremes. The total distances certain green turtles (Chelonia mydas) and loggerheads (Caretta caretta) traverse over the span of their lifetimes exceed tens of thousands of kilometres, several times the diameter of the turtle's home ocean basin. Adult migrations between feeding and nesting habitats can require continuous swimming for periods of several weeks. In addition, the paths of migrating turtles often lead almost straight across the open ocean and directly to the destination, leaving little doubt that turtles can navigate to distant target sites with remarkable efficiency.

Population trends and survival of nesting green sea turtles Chelonia mydas on Aves Island, Venezuela

USGS Publications Warehouse

Garcia-Cruz, Marco A.; Lampo, Margarita; Peñaloza, Claudia L.; Kendall, William L.; Solé, Genaro; Rodriguez-Clark, Kathryn M.

2015-01-01

Long-term demographic data are valuable for assessing the effect of anthropogenic impacts on endangered species and evaluating recovery programs. Using a 2-state open robust design model, we analyzed mark-recapture data from green turtles Chelonia mydas sighted between 1979 and 2009 on Aves Island, Venezuela, a rookery heavily impacted by human activities before it was declared a wildlife refuge in 1972. Based on the encounter histories of 7689 nesting females, we estimated the abundance, annual survival, and remigration intervals for this population. Female survival varied from 0.14-0.91, with a mean of 0.79, which is low compared to survival of other populations from the Caribbean (mean = 0.84) and Australia (mean = 0.95), even though we partially corrected for tag loss, which is known to negatively bias survival estimates. This supports prior suggestions that Caribbean populations in general, and the Aves Island population in particular, may be more strongly impacted than populations elsewhere. It is likely that nesters from this rookery are extracted while foraging in remote feeding grounds where hunting still occurs. Despite its relatively low survival, the nesting population at Aves Island increased during the past 30 years from approx. 500 to >1000 nesting females in 2009. Thus, this population, like others in the Caribbean and the Atlantic, seems to be slowly recovering following protective management. Although these findings support the importance of long-term conservation programs aimed at protecting nesting grounds, they also highlight the need to extend management actions to foraging grounds where human activities may still impact green turtle populations.

Climate Impacts on Sea Turtle Breeding Phenology in Greece and Associated Foraging Habitats in the Wider Mediterranean Region

PubMed Central

Morreale, Stephen J.; Saba, Vincent S.; Panagopoulou, Aliki; Margaritoulis, Dimitris; Spotila, James R.

2016-01-01

Sea turtles are vulnerable to climate change impacts in both their terrestrial (nesting beach) and oceanic habitats. From 1982 to 2012, air and sea surface temperatures at major high use foraging and nesting regions (n = 5) of loggerhead turtles (Caretta caretta) nesting in Greece have steadily increased. Here, we update the established relationships between sea surface temperature and nesting data from Zakynthos (latitude: 37.7°N), a major nesting beach, while also expanding these analyses to include precipitation and air temperature and additional nesting data from two other key beaches in Greece: Kyparissia Bay (latitude: 37.3°N) and Rethymno, Crete (latitude: 35.4°N). We confirmed that nesting phenology at Zakynthos has continued to be impacted by breeding season temperature; however, temperature has no consistent relationship with nest numbers, which are declining on Zakynthos and Crete but increasing at Kyparissia. Then using statistically downscaled outputs of 14 climate models assessed by the Intergovernmental Panel on Climate Change (IPCC), we projected future shifts in nesting for these populations. Based on the climate models, we projected that temperature at the key foraging and breeding sites (Adriatic Sea, Aegean Sea, Crete, Gulf of Gabès and Zakynthos/Kyparissia Bay; overall latitudinal range: 33.0°—45.8°N) for loggerhead turtles nesting in Greece will rise by 3–5°C by 2100. Our calculations indicate that the projected rise in air and ocean temperature at Zakynthos could cause the nesting season in this major rookery to shift to an earlier date by as much as 50–74 days by 2100. Although an earlier onset of the nesting season may provide minor relief for nest success as temperatures rise, the overall climatic changes to the various important habitats will most likely have an overall negative impact on this population. PMID:27332550

Climate Impacts on Sea Turtle Breeding Phenology in Greece and Associated Foraging Habitats in the Wider Mediterranean Region.

PubMed

Patel, Samir H; Morreale, Stephen J; Saba, Vincent S; Panagopoulou, Aliki; Margaritoulis, Dimitris; Spotila, James R

2016-01-01

Sea turtles are vulnerable to climate change impacts in both their terrestrial (nesting beach) and oceanic habitats. From 1982 to 2012, air and sea surface temperatures at major high use foraging and nesting regions (n = 5) of loggerhead turtles (Caretta caretta) nesting in Greece have steadily increased. Here, we update the established relationships between sea surface temperature and nesting data from Zakynthos (latitude: 37.7°N), a major nesting beach, while also expanding these analyses to include precipitation and air temperature and additional nesting data from two other key beaches in Greece: Kyparissia Bay (latitude: 37.3°N) and Rethymno, Crete (latitude: 35.4°N). We confirmed that nesting phenology at Zakynthos has continued to be impacted by breeding season temperature; however, temperature has no consistent relationship with nest numbers, which are declining on Zakynthos and Crete but increasing at Kyparissia. Then using statistically downscaled outputs of 14 climate models assessed by the Intergovernmental Panel on Climate Change (IPCC), we projected future shifts in nesting for these populations. Based on the climate models, we projected that temperature at the key foraging and breeding sites (Adriatic Sea, Aegean Sea, Crete, Gulf of Gabès and Zakynthos/Kyparissia Bay; overall latitudinal range: 33.0°-45.8°N) for loggerhead turtles nesting in Greece will rise by 3-5°C by 2100. Our calculations indicate that the projected rise in air and ocean temperature at Zakynthos could cause the nesting season in this major rookery to shift to an earlier date by as much as 50-74 days by 2100. Although an earlier onset of the nesting season may provide minor relief for nest success as temperatures rise, the overall climatic changes to the various important habitats will most likely have an overall negative impact on this population.

Deforestation: risk of sex ratio distortion in hawksbill sea turtles.

PubMed

Kamel, Stephanie Jill; Mrosovsky, N

2006-06-01

Phenotypic sex in sea turtles is determined by nest incubation temperatures, with warmer temperatures producing females and cooler temperatures producing males. The common finding of highly skewed female-biased hatchling sex ratios in sea turtle populations could have serious repercussions for the long-term survival of these species and prompted us to examine the thermal profile of a relatively pristine hawksbill nesting beach in Guadeloupe, French West Indies. Data loggers placed at nest depth revealed that temperatures in the forested areas were significantly cooler than temperatures in the more open, deforested areas. Using these temperatures as a predictor of sex ratio, we were able to assess the relative contributions of the different beach zones to the primary sex ratio: significantly more males were likely to be produced in the forested areas. Coastal forests are therefore important male-producing areas for the hawksbill sea turtle, and this has urgent conservation implications. On Guadeloupe, as on many Caribbean islands, deforestation rates are high and show few signs of slowing, as there is continual pressure to develop beachfront areas. The destruction of coastal forest could have serious consequences both in terms of local nesting behavior and of regional demography through the effects on population sex ratios. Human alterations to nesting habitat in other reptile taxa have been shown to modify the thermal properties of nest sites in ways that can disrupt their ecology by allowing parasite transmission, increasing vulnerability to climate change, or rendering existing habitat unsuitable.

Temporospatial dynamics and public health significance of bacterial flora identified on a major leatherback turtle (Dermochelys coriacea) nesting beach in the Southern Caribbean

USGS Publications Warehouse

Phillips, Ayanna Carla N.; Couteau, Johanna; Rajh, Stacy; Stewart, Neville; Watson, Antonio; Jehu, Adam; Asmath, Hamish; Unakal, Chandrashekhar; Dziva, Francis; Holder, Ridley; Carthy, Raymond R.

2017-01-01

Grande Riviere beach, on the island of Trinidad, supports the largest nesting population of leatherback turtles in the Caribbean region. Throughout the nesting season, nests are naturally disturbed by newly nesting females, resulting in egg breakage and loss of some nest viability. This environment is ideal for the growth and proliferation of microorganisms. The range of bacterial flora present in beach sand and egg shells was examined, with emphasis on bacteria that may pose a threat to public and animal health. The extent to which the bacterial load and genera on the beach changed throughout the season was also assessed. Twenty-five genera were identified, with Pseudomonas spp. found to be the most predominant environmental bacteria. Four genera identified possess zoonotic potential, while five additional genera are known to be of public and animal health significance. Distinct shifts in the density and distribution of bacteria were observed along the beach from early to peak nesting season. Shifts were seen across heavily traversed zones, thus highlighting the potential exposure threats posed to beach visitors and animals alike. Further studies aimed at speciating this population of bacteria, as well as isolating potential fungal pathogens may mitigate this threat. Identification of bacterial agents that are specifically pathogenic to leatherback turtles, turtle eggs, hatchlings and those who may interact with these animals will serve to enhance and guide efforts to better conserve this species and protect the health of all who visit this ecologically significant site.

Long-Term Climate Forcing in Loggerhead Sea Turtle Nesting

PubMed Central

Van Houtan, Kyle S.; Halley, John M.

2011-01-01

The long-term variability of marine turtle populations remains poorly understood, limiting science and management. Here we use basin-scale climate indices and regional surface temperatures to estimate loggerhead sea turtle (Caretta caretta) nesting at a variety of spatial and temporal scales. Borrowing from fisheries research, our models investigate how oceanographic processes influence juvenile recruitment and regulate population dynamics. This novel approach finds local populations in the North Pacific and Northwest Atlantic are regionally synchronized and strongly correlated to ocean conditions—such that climate models alone explain up to 88% of the observed changes over the past several decades. In addition to its performance, climate-based modeling also provides mechanistic forecasts of historical and future population changes. Hindcasts in both regions indicate climatic conditions may have been a factor in recent declines, but future forecasts are mixed. Available climatic data suggests the Pacific population will be significantly reduced by 2040, but indicates the Atlantic population may increase substantially. These results do not exonerate anthropogenic impacts, but highlight the significance of bottom-up oceanographic processes to marine organisms. Future studies should consider environmental baselines in assessments of marine turtle population variability and persistence. PMID:21589639

Long-term climate forcing in loggerhead sea turtle nesting.

PubMed

Van Houtan, Kyle S; Halley, John M

2011-04-27

The long-term variability of marine turtle populations remains poorly understood, limiting science and management. Here we use basin-scale climate indices and regional surface temperatures to estimate loggerhead sea turtle (Caretta caretta) nesting at a variety of spatial and temporal scales. Borrowing from fisheries research, our models investigate how oceanographic processes influence juvenile recruitment and regulate population dynamics. This novel approach finds local populations in the North Pacific and Northwest Atlantic are regionally synchronized and strongly correlated to ocean conditions--such that climate models alone explain up to 88% of the observed changes over the past several decades. In addition to its performance, climate-based modeling also provides mechanistic forecasts of historical and future population changes. Hindcasts in both regions indicate climatic conditions may have been a factor in recent declines, but future forecasts are mixed. Available climatic data suggests the Pacific population will be significantly reduced by 2040, but indicates the Atlantic population may increase substantially. These results do not exonerate anthropogenic impacts, but highlight the significance of bottom-up oceanographic processes to marine organisms. Future studies should consider environmental baselines in assessments of marine turtle population variability and persistence.

Mercury in blood and eggs of the sea turtle Lepidochelys olivacea from a nesting colony in Oaxaca, Mexico.

PubMed

Páez-Osuna, F; Calderón-Campuzano, M F; Soto-Jiménez, M F; Ruelas-Inzunza, J

2011-06-01

Mercury concentrations were assessed in the sea turtle Lepidochelys olivacea from a nesting colony of Oaxaca, Mexico; 25 female turtles were sampled, a total of 250 eggs were collected during the season 2005-2006. Higher concentrations were found in yolk fraction, while in blood and albumen mean levels were below of 0.0010μg g(-1) dry wt. On the basis of one nesting season, the maternal transfer of Hg via eggs-laying was estimated in 2.0±1.1%. According to international norms, the health of this population and its habitats is acceptable for Hg and corresponds to baseline levels of a nearly pristine environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

Testing models of female reproductive migratory behaviour and population structure in the Caribbean hawksbill turtle, Eretmochelys imbricata, with mtDNA sequences.

PubMed

Bass, A L; Good, D A; Bjorndal, K A; Richardson, J I; Hillis, Z M; Horrocks, J A; Bowen, B W

1996-06-01

Information on the reproductive behaviour and population structure of female hawksbill turtles, Eretmochelys imbricata, is necessary to define conservation priorities for this highly endangered species. Two hypotheses to explain female nest site choice, natal homing and social facilitation, were tested by analyzing mtDNA control region sequences of 103 individuals from seven nesting colonies in the Caribbean and western Atlantic. Under the social facilitation model, newly mature females follow older females to a nesting location, and subsequently use this site for future nesting. This model generates an expectation that female lineages will be homogenized among regional nesting colonies. Contrary to expectations of the social facilitation model, mtDNA lineages were highly structured among western Atlantic nesting colonies. These analyses identified at least 6 female breeding stocks in the Caribbean and western Atlantic and support a natal homing model for recruitment of breeding females. Reproductive populations are effectively isolated over ecological time scales, and recovery plans for this species should include protection at the level of individual nesting colonies.

Inter-seasonal maintenance of individual nest site preferences in hawksbill sea turtles.

PubMed

Kamel, Stephanie J; Mrosovsky, N

2006-11-01

Within a single population of hawksbill sea turtles (Eretmochelys imbricata), we found a behavioral polymorphism for maternal nest site choice with respect to beach microhabitat characteristics. Some females preferred to nest in littoral forest and in places with overstory vegetation cover, and others preferred to nest in more open, deforested areas. Nest site choice was consistent within and between nesting seasons two years apart. This was not a result of females simply returning to the same location along the shoreline; beach sections used by individual turtles varied between seasons. Nest site choice was not influenced by changes in beach environment (e.g., beach width and foliage cover) or by changes in females' reproductive output (e.g., clutch size), suggesting that fidelity to particular microhabitats is a major determinant of the observed nesting patterns. Because hawksbills exhibit temperature-dependent sex determination, if the behavioral polymorphism in nest site choice has a genetic basis, as is plausible, then this would have implications for sex ratio evolution and offspring survival. By taking an individual-based approach to the study of maternal behavior we reveal previously overlooked individual variation and hope to provide some impetus for more detailed studies of nest site choice.

Western Pond Turtle Head-starting and Reintroduction, 2005-2006 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Leuven, Susan; Allen, Harriet; Slavens, Kate

This report covers the results of the western pond turtle head-starting and reintroduction project for the period of October 2005-September 2006. Wild hatchling western pond turtles from the Columbia River Gorge were reared at the Woodland Park and Oregon zoos in 2005 and 2006 as part of the recovery effort for this Washington State endangered species. The objective of the program is to reduce losses to introduced predators like bullfrogs and largemouth bass by raising the hatchlings to a size where they are too large to be eaten by most of these predators. Twenty-six turtles were placed at the Woodlandmore » Park Zoo and 62 at the Oregon Zoo in fall 2005. These turtles joined two that were held back from release in summer 2005 due to their small size. All 90 juvenile turtles were released at three sites in the Columbia Gorge in 2006. Twenty-eight juvenile turtles were released at the Klickitat ponds, 22 at the Klickitat lake, 21 at the Skamania site, and 19 at Pierce National Wildlife Refuge (NWR). This brought the total number of head-start turtles released since 1991 to 944; 285 for the Klickitat ponds, 158 for the Klickitat lake, 227 for the Skamania pond complex, and 274 at Pierce NWR. In 2006, 20 females from the Klickitat population were equipped with transmitters and monitored for nesting activity. Fifteen nests were located and protected; these produced 55 hatchlings. The hatchlings were collected in September and transported to the Oregon and Woodland Park zoos for rearing in the head-start program. One wild hatchling captured in spring 2006 was placed in the head-start program to attain more growth in captivity. During the 2006 field season trapping effort, 414 western pond turtles were captured in the Columbia Gorge, including 374 previously head-started turtles. These recaptures, together with confirmed nesting by head-start females and visual resightings, indicate the program is succeeding in boosting juvenile recruitment to increase the populations. Records were also collected on 179 individual painted turtles captured in 2006 during trapping efforts at Pierce NWR, to gather baseline information on this native population.« less

Persistent leatherback turtle migrations present opportunities for conservation.

PubMed

Shillinger, George L; Palacios, Daniel M; Bailey, Helen; Bograd, Steven J; Swithenbank, Alan M; Gaspar, Philippe; Wallace, Bryan P; Spotila, James R; Paladino, Frank V; Piedra, Rotney; Eckert, Scott A; Block, Barbara A

2008-07-15

Effective transboundary conservation of highly migratory marine animals requires international management cooperation as well as clear scientific information about habitat use by these species. Populations of leatherback turtles (Dermochelys coriacea) in the eastern Pacific have declined by >90% during the past two decades, primarily due to unsustainable egg harvest and fisheries bycatch mortality. While research and conservation efforts on nesting beaches are ongoing, relatively little is known about this population of leatherbacks' oceanic habitat use and migration pathways. We present the largest multi-year (2004-2005, 2005-2006, and 2007) satellite tracking dataset (12,095 cumulative satellite tracking days) collected for leatherback turtles. Forty-six females were electronically tagged during three field seasons at Playa Grande, Costa Rica, the largest extant nesting colony in the eastern Pacific. After completing nesting, the turtles headed southward, traversing the dynamic equatorial currents with rapid, directed movements. In contrast to the highly varied dispersal patterns seen in many other sea turtle populations, leatherbacks from Playa Grande traveled within a persistent migration corridor from Costa Rica, past the equator, and into the South Pacific Gyre, a vast, low-energy, low-productivity region. We describe the predictable effects of ocean currents on a leatherback migration corridor and characterize long-distance movements by the turtles in the eastern South Pacific. These data from high seas habitats will also elucidate potential areas for mitigating fisheries bycatch interactions. These findings directly inform existing multinational conservation frameworks and provide immediate regions in the migration corridor where conservation can be implemented. We identify high seas locations for focusing future conservation efforts within the leatherback dispersal zone in the South Pacific Gyre.

Magnetic Navigation in Sea Turtles: Insights from Secular Variation

NASA Astrophysics Data System (ADS)

Putman, N. F.; Lohmann, K.

2011-12-01

Sea turtles are iconic migrants that posses a sensitive magnetic-sense that guides their long-distance movements in a variety of contexts. In the first few hours after hatching turtles use the magnetic field to maintain an offshore compass heading to reach deeper water, out of the reach of nearshore predators. Young turtles engage in directed swimming in response to regional magnetic fields that exist along their transoceanic migratory path. Older turtles also use magnetic information to relocate foraging sites and islands used for nesting after displacement. Numerous hypotheses have been put forth to explain how magnetic information functions in these movements, however, there is little consensus among animal navigation researchers. A particular vexing issue is how magnetic navigation can function under the constraints of the constant, gradual shifting of the earth's magnetic field (secular variation). Here, I present a framework based on models of recent geomagnetic secular variation to explore several navigational mechanisms proposed for sea turtles. I show that while examination of secular variation likely falsifies some hypothetical navigational strategies, it provides key insights into the selective pressures that could maintain other navigational mechanisms. Moreover, examination of secular variation's influence on the navigational precision in reproductive migrations of sea turtles offers compelling explanations for the population structure along sea turtle nesting beaches as well as spatiotemporal variation in nesting turtle abundance.

Climate change overruns resilience conferred by temperature-dependent sex determination in sea turtles and threatens their survival.

PubMed

Santidrián Tomillo, Pilar; Genovart, Meritxell; Paladino, Frank V; Spotila, James R; Oro, Daniel

2015-08-01

Temperature-dependent sex determination (TSD) is the predominant form of environmental sex determination (ESD) in reptiles, but the adaptive significance of TSD in this group remains unclear. Additionally, the viability of species with TSD may be compromised as climate gets warmer. We simulated population responses in a turtle with TSD to increasing nest temperatures and compared the results to those of a virtual population with genotypic sex determination (GSD) and fixed sex ratios. Then, we assessed the effectiveness of TSD as a mechanism to maintain populations under climate change scenarios. TSD populations were more resilient to increased nest temperatures and mitigated the negative effects of high temperatures by increasing production of female offspring and therefore, future fecundity. That buffered the negative effect of temperature on the population growth. TSD provides an evolutionary advantage to sea turtles. However, this mechanism was only effective over a range of temperatures and will become inefficient as temperatures rise to levels projected by current climate change models. Projected global warming threatens survival of sea turtles, and the IPCC high gas concentration scenario may result in extirpation of the studied population in 50 years. © 2015 John Wiley & Sons Ltd.

Global sea turtle conservation successes

PubMed Central

Mazaris, Antonios D.; Schofield, Gail; Gkazinou, Chrysoula; Almpanidou, Vasiliki; Hays, Graeme C.

2017-01-01

We document a tendency for published estimates of population size in sea turtles to be increasing rather than decreasing across the globe. To examine the population status of the seven species of sea turtle globally, we obtained 299 time series of annual nesting abundance with a total of 4417 annual estimates. The time series ranged in length from 6 to 47 years (mean, 16.2 years). When levels of abundance were summed within regional management units (RMUs) for each species, there were upward trends in 12 RMUs versus downward trends in 5 RMUs. This prevalence of more upward than downward trends was also evident in the individual time series, where we found 95 significant increases in abundance and 35 significant decreases. Adding to this encouraging news for sea turtle conservation, we show that even small sea turtle populations have the capacity to recover, that is, Allee effects appear unimportant. Positive trends in abundance are likely linked to the effective protection of eggs and nesting females, as well as reduced bycatch. However, conservation concerns remain, such as the decline in leatherback turtles in the Eastern and Western Pacific. Furthermore, we also show that, often, time series are too short to identify trends in abundance. Our findings highlight the importance of continued conservation and monitoring efforts that underpin this global conservation success story. PMID:28948215

Tupinambis merianae as nest predators of crocodilians and turtles in Florida, USA

USGS Publications Warehouse

Mazzotti, Frank J.; McEachern, Michelle A.; Rochford, Michael; Reed, Robert; Ketterlin Eckles, Jennifer; Vinci, Joy; Edwards, Jake; Wasilewki, Joseph

2015-01-01

Tupinambis merianae, is a large, omnivorous tegu lizard native to South America. Two populations of tegus are established in the state of Florida, USA, but impacts to native species are poorly documented. During summer 2013, we placed automated cameras overlooking one American alligator (Alligator mississippiensis) nest, which also contained a clutch of Florida red-bellied cooter (Pseudemys nelsoni) eggs, and one American crocodile (Crocodylus acutus) nest at a site in southeastern Florida where tegus are established. We documented tegu activity and predation on alligator and turtle eggs at the alligator nest, and tegu activity at the crocodile nest. Our finding that one of the first two crocodilian nests to be monitored was depredated by tegus suggests that tegus should be further evaluated as a threat to nesting reptiles in Florida.

Serum gonadotropins and gonadal steroids associated with ovulation and egg production in sea turtles.

PubMed

Wibbels, T; Owens, D W; Licht, P; Limpus, C; Reed, P C; Amoss, M S

1992-07-01

Changes in serum concentrations of gonadotropins and gonadal steroids during the periovulatory period were monitored in green, Chelonia mydas, and loggerhead, Caretta caretta, sea turtles. Turtles were from natural populations that nest on a coral island on the Great Barrier Reef. After nesting, each turtle was transferred to a holding tank and held for a maximum of 8 days. A time series of blood samples was obtained from each of five sea turtles (three C. mydas and two C. caretta) starting immediately after nesting and then at approximately 12-hr intervals until the time of release. Prior to release back into the ocean, each turtle was examined by laparoscopy to verify that ovulation had occurred. Serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), progesterone (PRO), and testosterone (T) in both species exhibited significant changes during this period. Surges of FSH, LH, and PRO were evident within approximately 20 to 50 hr after each turtle had nested. The significant change in FSH concentration during the periovulatory period is the first such report for a reptile. Coincident with maximal concentrations of FSH, LH, and PRO was a decline in T concentrations in both species. Estradiol-17 beta concentrations were near or below assay sensitivity in the C. mydas, whereas those in the C. caretta were detectable but exhibited no significant changes. The dynamic changes in FSH, LH, PRO, and T concentrations are consistent with the hypothesis that these hormones facilitate specific physiological events during ovulation and egg production.

Dispersal and Diving Adjustments of the Green Turtle Chelonia mydas in Response to Dynamic Environmental Conditions during Post-Nesting Migration

PubMed Central

Chambault, Philippine; Pinaud, David; Vantrepotte, Vincent; Kelle, Laurent; Entraygues, Mathieu; Guinet, Christophe; Berzins, Rachel; Bilo, Karin; Gaspar, Philippe; de Thoisy, Benoît; Le Maho, Yvon; Chevallier, Damien

2015-01-01

In response to seasonality and spatial segregation of resources, sea turtles undertake long journeys between their nesting sites and foraging grounds. While satellite tracking has made it possible to outline their migration routes, we still have little knowledge of how they select their foraging grounds and adapt their migration to dynamic environmental conditions. Here, we analyzed the trajectories and diving behavior of 19 adult green turtles (Chelonia mydas) during their post-nesting migration from French Guiana and Suriname to their foraging grounds off the coast of Brazil. First Passage Time analysis was used to identify foraging areas located off Ceará state of Brazil, where the associated habitat corresponds to favorable conditions for seagrass growth, i.e. clear and shallow waters. The dispersal and diving patterns of the turtles revealed several behavioral adaptations to the strong hydrodynamic processes induced by both the North Brazil current and the Amazon River plume. All green turtles migrated south-eastward after the nesting season, confirming that they coped with the strong counter North Brazil current by using a tight corridor close to the shore. The time spent within the Amazon plume also altered the location of their feeding habitats as the longer individuals stayed within the plume, the sooner they initiated foraging. The green turtles performed deeper and shorter dives while crossing the mouth of the Amazon, a strategy which would help turtles avoid the most turbulent upper surface layers of the plume. These adjustments reveal the remarkable plasticity of this green turtle population when reducing energy costs induced by migration. PMID:26398528

Dispersal and Diving Adjustments of the Green Turtle Chelonia mydas in Response to Dynamic Environmental Conditions during Post-Nesting Migration.

PubMed

Chambault, Philippine; Pinaud, David; Vantrepotte, Vincent; Kelle, Laurent; Entraygues, Mathieu; Guinet, Christophe; Berzins, Rachel; Bilo, Karin; Gaspar, Philippe; de Thoisy, Benoît; Le Maho, Yvon; Chevallier, Damien

2015-01-01

In response to seasonality and spatial segregation of resources, sea turtles undertake long journeys between their nesting sites and foraging grounds. While satellite tracking has made it possible to outline their migration routes, we still have little knowledge of how they select their foraging grounds and adapt their migration to dynamic environmental conditions. Here, we analyzed the trajectories and diving behavior of 19 adult green turtles (Chelonia mydas) during their post-nesting migration from French Guiana and Suriname to their foraging grounds off the coast of Brazil. First Passage Time analysis was used to identify foraging areas located off Ceará state of Brazil, where the associated habitat corresponds to favorable conditions for seagrass growth, i.e. clear and shallow waters. The dispersal and diving patterns of the turtles revealed several behavioral adaptations to the strong hydrodynamic processes induced by both the North Brazil current and the Amazon River plume. All green turtles migrated south-eastward after the nesting season, confirming that they coped with the strong counter North Brazil current by using a tight corridor close to the shore. The time spent within the Amazon plume also altered the location of their feeding habitats as the longer individuals stayed within the plume, the sooner they initiated foraging. The green turtles performed deeper and shorter dives while crossing the mouth of the Amazon, a strategy which would help turtles avoid the most turbulent upper surface layers of the plume. These adjustments reveal the remarkable plasticity of this green turtle population when reducing energy costs induced by migration.

Nest temperatures in a loggerhead nesting beach in Turkey is more determined by sea surface than air temperature.

PubMed

Girondot, Marc; Kaska, Yakup

2015-01-01

While climate change is now fully recognised as a reality, its impact on biodiversity is still not completely understood. To predict its impact, proxies coherent with the studied ecosystem or species are thus required. Marine turtles are threatened worldwide (though some populations are recovering) as they are particularly sensitive to temperature throughout their entire life cycle. This is especially true at the embryo stage when temperature affects both growth rates and sex determination. Nest temperature is thus of prime importance to understand the persistence of populations in the context of climate change. We analysed the nest temperature of 21 loggerheads (Caretta caretta) originating from Dalyan Beach in Turkey using day-lagged generalised mixed models with autocorrelation. Surprisingly, the selected model for nest temperature includes an effect for sea surface temperature 4-times higher than for air temperature. We also detected a very significant effect of metabolic heating during development compatible with what is already known about marine turtle nests. Our new methodology allows the prediction of marine turtle nest temperatures with good precision based on a combination of air temperature measured at beach level and sea surface temperature in front of the beach. These data are available in public databases for most of the beaches worldwide. Copyright © 2014 Elsevier Ltd. All rights reserved.

Global Distribution of Two Fungal Pathogens Threatening Endangered Sea Turtles

PubMed Central

Sarmiento-Ramírez, Jullie M.; Abella-Pérez, Elena; Phillott, Andrea D.; Sim, Jolene; van West, Pieter; Martín, María P.; Marco, Adolfo; Diéguez-Uribeondo, Javier

2014-01-01

Nascent fungal infections are currently considered as one of the main threats for biodiversity and ecosystem health, and have driven several animal species into critical risk of extinction. Sea turtles are one of the most endangered groups of animals and only seven species have survived to date. Here, we described two pathogenic species, i.e., Fusarium falciforme and Fusarium keratoplasticum, that are globally distributed in major turtle nesting areas for six sea turtle species and that are implicated in low hatch success. These two fungi possess key biological features that are similar to emerging pathogens leading to host extinction, e.g., high virulence, and a broad host range style of life. Their optimal growth temperature overlap with the optimal incubation temperature for eggs, and they are able to kill up to 90% of the embryos. Environmental forcing, e.g., tidal inundation and clay/silt content of nests, were correlated to disease development. Thus, these Fusarium species constitute a major threat to sea turtle nests, especially to those experiencing environmental stressors. These findings have serious implications for the survival of endangered sea turtle populations and the success of conservation programs worldwide. PMID:24465748

Global distribution of two fungal pathogens threatening endangered sea turtles.

PubMed

Sarmiento-Ramírez, Jullie M; Abella-Pérez, Elena; Phillott, Andrea D; Sim, Jolene; van West, Pieter; Martín, María P; Marco, Adolfo; Diéguez-Uribeondo, Javier

2014-01-01

Nascent fungal infections are currently considered as one of the main threats for biodiversity and ecosystem health, and have driven several animal species into critical risk of extinction. Sea turtles are one of the most endangered groups of animals and only seven species have survived to date. Here, we described two pathogenic species, i.e., Fusarium falciforme and Fusarium keratoplasticum, that are globally distributed in major turtle nesting areas for six sea turtle species and that are implicated in low hatch success. These two fungi possess key biological features that are similar to emerging pathogens leading to host extinction, e.g., high virulence, and a broad host range style of life. Their optimal growth temperature overlap with the optimal incubation temperature for eggs, and they are able to kill up to 90% of the embryos. Environmental forcing, e.g., tidal inundation and clay/silt content of nests, were correlated to disease development. Thus, these Fusarium species constitute a major threat to sea turtle nests, especially to those experiencing environmental stressors. These findings have serious implications for the survival of endangered sea turtle populations and the success of conservation programs worldwide.

Biochemical indices and life traits of loggerhead turtles (Caretta caretta) from Cape Verde Islands.

PubMed

Vieira, Sara; Martins, Samir; Hawkes, Lucy A; Marco, Adolfo; Teodósio, M Alexandra

2014-01-01

The loggerhead turtle (Caretta caretta) is an endangered marine reptile for whom assessing population health requires knowledge of demographic parameters such as individual growth rate. In Cape Verde, as within several populations, adult female loggerhead sea turtles show a size-related behavioral and trophic dichotomy. While smaller females are associated with oceanic habitats, larger females tend to feed in neritic habitats, which is reflected in their physiological condition and in their offspring. The ratio of RNA/DNA provides a measure of cellular protein synthesis capacity, which varies depending on changes in environmental conditions such as temperature and food availability. The purpose of this study was to evaluate the combined use of morphometric data and biochemical indices as predictors of the physiological condition of the females of distinct sizes and hatchlings during their nesting season and how temperature may influence the physiological condition on the offspring. Here we employed biochemical indices based on nucleic acid derived indices (standardized RNA/DNA ratio-sRD, RNA concentration and DNA concentration) in skin tissue as a potential predictor of recent growth rate in nesting females and hatchling loggerhead turtles. Our major findings were that the physiological condition of all nesting females (sRD) decreased during the nesting season, but that females associated with neritic habitats had a higher physiological condition than females associated with oceanic habitats. In addition, the amount of time required for a hatchling to right itself was negatively correlated with its physiological condition (sRD) and shaded nests produced hatchlings with lower sRD. Overall, our results showed that nucleic acid concentrations and ratios of RNA to DNA are an important tool as potential biomarkers of recent growth in marine turtles. Hence, as biochemical indices of instantaneous growth are likely temperature-, size- and age-dependent, the utility and validation of these indices on marine turtles stocks deserves further study.

Biochemical Indices and Life Traits of Loggerhead Turtles (Caretta caretta) from Cape Verde Islands

PubMed Central

Vieira, Sara; Martins, Samir; Hawkes, Lucy A.; Marco, Adolfo; Teodósio, M. Alexandra

2014-01-01

The loggerhead turtle (Caretta caretta) is an endangered marine reptile for whom assessing population health requires knowledge of demographic parameters such as individual growth rate. In Cape Verde, as within several populations, adult female loggerhead sea turtles show a size-related behavioral and trophic dichotomy. While smaller females are associated with oceanic habitats, larger females tend to feed in neritic habitats, which is reflected in their physiological condition and in their offspring. The ratio of RNA/DNA provides a measure of cellular protein synthesis capacity, which varies depending on changes in environmental conditions such as temperature and food availability. The purpose of this study was to evaluate the combined use of morphometric data and biochemical indices as predictors of the physiological condition of the females of distinct sizes and hatchlings during their nesting season and how temperature may influence the physiological condition on the offspring. Here we employed biochemical indices based on nucleic acid derived indices (standardized RNA/DNA ratio-sRD, RNA concentration and DNA concentration) in skin tissue as a potential predictor of recent growth rate in nesting females and hatchling loggerhead turtles. Our major findings were that the physiological condition of all nesting females (sRD) decreased during the nesting season, but that females associated with neritic habitats had a higher physiological condition than females associated with oceanic habitats. In addition, the amount of time required for a hatchling to right itself was negatively correlated with its physiological condition (sRD) and shaded nests produced hatchlings with lower sRD. Overall, our results showed that nucleic acid concentrations and ratios of RNA to DNA are an important tool as potential biomarkers of recent growth in marine turtles. Hence, as biochemical indices of instantaneous growth are likely temperature-, size- and age-dependent, the utility and validation of these indices on marine turtles stocks deserves further study. PMID:25390348

Climate change impacts on leatherback turtle pelagic habitat in the Southeast Pacific

NASA Astrophysics Data System (ADS)

Willis-Norton, Ellen; Hazen, Elliott L.; Fossette, Sabrina; Shillinger, George; Rykaczewski, Ryan R.; Foley, David G.; Dunne, John P.; Bograd, Steven J.

2015-03-01

Eastern Pacific populations of the leatherback turtle (Dermochelys coriacea) have declined by over 90% during the past three decades. The decline is primarily attributed to human pressures, including unsustainable egg harvest, development on nesting beaches, and by-catch mortality. In particular, the effects of climate change may impose additional stresses upon already threatened leatherback populations. This study analyzes how the pelagic habitat of Eastern Pacific leatherbacks may be affected by climate change over the next century. This population adheres to a persistent migration pattern; following nesting at Playa Grande, Costa Rica, individuals move rapidly through equatorial currents and into foraging habitat within the oligotrophic South Pacific Gyre. Forty-six nesting females were fitted with satellite tags. Based on the turtle positions, ten environmental variables were sampled along the tracks. Presence/absence habitat models were created to determine the oceanographic characteristics of the preferred turtle habitat. Core pelagic habitat was characterized by relatively low sea surface temperatures and chlorophyll-a. Based on these habitat models, we predicted habitat change using output from the Geophysical Fluid Dynamics Laboratory prototype Earth System Model under the Special Report on Emissions Scenario A2 (business-as-usual). Although the model predicted both habitat losses and gains throughout the region, we estimated that overall the core pelagic habitat of the Eastern Pacific leatherback population will decline by approximately 15% within the next century. This habitat modification might increase pressure on a critically endangered population, possibly forcing distributional shifts, behavioral changes, or even extinction.

Forecasting the viability of sea turtle eggs in a warming world.

PubMed

Pike, David A

2014-01-01

Animals living in tropical regions may be at increased risk from climate change because current temperatures at these locations already approach critical physiological thresholds. Relatively small temperature increases could cause animals to exceed these thresholds more often, resulting in substantial fitness costs or even death. Oviparous species could be especially vulnerable because the maximum thermal tolerances of incubating embryos is often lower than adult counterparts, and in many species mothers abandon the eggs after oviposition, rendering them immobile and thus unable to avoid extreme temperatures. As a consequence, the effects of climate change might become evident earlier and be more devastating for hatchling production in the tropics. Loggerhead sea turtles (Caretta caretta) have the widest nesting range of any living reptile, spanning temperate to tropical latitudes in both hemispheres. Currently, loggerhead sea turtle populations in the tropics produce nearly 30% fewer hatchlings per nest than temperate populations. Strong correlations between empirical hatching success and habitat quality allowed global predictions of the spatiotemporal impacts of climate change on this fitness trait. Under climate change, many sea turtle populations nesting in tropical environments are predicted to experience severe reductions in hatchling production, whereas hatching success in many temperate populations could remain unchanged or even increase with rising temperatures. Some populations could show very complex responses to climate change, with higher relative hatchling production as temperatures begin to increase, followed by declines as critical physiological thresholds are exceeded more frequently. Predicting when, where, and how climate change could impact the reproductive output of local populations is crucial for anticipating how a warming world will influence population size, growth, and stability.

Breeding Sex Ratios in Adult Leatherback Turtles (Dermochelys coriacea) May Compensate for Female-Biased Hatchling Sex Ratios

PubMed Central

Stewart, Kelly R.; Dutton, Peter H.

2014-01-01

For vertebrates with temperature-dependent sex determination, primary (or hatchling) sex ratios are often skewed, an issue of particular relevance to concerns over effects of climate change on populations. However, the ratio of breeding males to females, or the operational sex ratio (OSR), is important to understand because it has consequences for population demographics and determines the capacity of a species to persist. The OSR also affects mating behaviors and mate choice, depending on the more abundant sex. For sea turtles, hatchling and juvenile sex ratios are generally female-biased, and with warming nesting beach temperatures, there is concern that populations may become feminized. Our purpose was to evaluate the breeding sex ratio for leatherback turtles at a nesting beach in St. Croix, USVI. In 2010, we sampled nesting females and later sampled their hatchlings as they emerged from nests. Total genomic DNA was extracted and all individuals were genotyped using 6 polymorphic microsatellite markers. We genotyped 662 hatchlings from 58 females, matching 55 females conclusively to their nests. Of the 55, 42 females mated with one male each, 9 mated with 2 males each and 4 mated with at least 3 males each, for a multiple paternity rate of 23.6%. Using GERUD1.0, we reconstructed parental genotypes, identifying 47 different males and 46 females for an estimated breeding sex ratio of 1.02 males for every female. Thus we demonstrate that there are as many actively breeding males as females in this population. Concerns about female-biased adult sex ratios may be premature, and mate choice or competition may play more of a role in sea turtle reproduction than previously thought. We recommend monitoring breeding sex ratios in the future to allow the integration of this demographic parameter in population models. PMID:24505403

Isotope analysis reveals foraging area dichotomy for atlantic leatherback turtles.

PubMed

Caut, Stéphane; Fossette, Sabrina; Guirlet, Elodie; Angulo, Elena; Das, Krishna; Girondot, Marc; Georges, Jean-Yves

2008-03-26

The leatherback turtle (Dermochelys coriacea) has undergone a dramatic decline over the last 25 years, and this is believed to be primarily the result of mortality associated with fisheries bycatch followed by egg and nesting female harvest. Atlantic leatherback turtles undertake long migrations across ocean basins from subtropical and tropical nesting beaches to productive frontal areas. Migration between two nesting seasons can last 2 or 3 years, a time period termed the remigration interval (RI). Recent satellite transmitter data revealed that Atlantic leatherbacks follow two major dispersion patterns after nesting season, through the North Gulf Stream area or more eastward across the North Equatorial Current. However, information on the whole RI is lacking, precluding the accurate identification of feeding areas where conservation measures may need to be applied. Using stable isotopes as dietary tracers we determined the characteristics of feeding grounds of leatherback females nesting in French Guiana. During migration, 3-year RI females differed from 2-year RI females in their isotope values, implying differences in their choice of feeding habitats (offshore vs. more coastal) and foraging latitude (North Atlantic vs. West African coasts, respectively). Egg-yolk and blood isotope values are correlated in nesting females, indicating that egg analysis is a useful tool for assessing isotope values in these turtles, including adults when not available. Our results complement previous data on turtle movements during the first year following the nesting season, integrating the diet consumed during the year before nesting. We suggest that the French Guiana leatherback population segregates into two distinct isotopic groupings, and highlight the urgent need to determine the feeding habitats of the turtle in the Atlantic in order to protect this species from incidental take by commercial fisheries. Our results also emphasize the use of eggs, a less-invasive sampling material than blood, to assess isotopic data and feeding habits for adult female leatherbacks.

Isotope Analysis Reveals Foraging Area Dichotomy for Atlantic Leatherback Turtles

PubMed Central

Angulo, Elena; Das, Krishna; Girondot, Marc

2008-01-01

Background The leatherback turtle (Dermochelys coriacea) has undergone a dramatic decline over the last 25 years, and this is believed to be primarily the result of mortality associated with fisheries bycatch followed by egg and nesting female harvest. Atlantic leatherback turtles undertake long migrations across ocean basins from subtropical and tropical nesting beaches to productive frontal areas. Migration between two nesting seasons can last 2 or 3 years, a time period termed the remigration interval (RI). Recent satellite transmitter data revealed that Atlantic leatherbacks follow two major dispersion patterns after nesting season, through the North Gulf Stream area or more eastward across the North Equatorial Current. However, information on the whole RI is lacking, precluding the accurate identification of feeding areas where conservation measures may need to be applied. Methodology/Principal Findings Using stable isotopes as dietary tracers we determined the characteristics of feeding grounds of leatherback females nesting in French Guiana. During migration, 3-year RI females differed from 2-year RI females in their isotope values, implying differences in their choice of feeding habitats (offshore vs. more coastal) and foraging latitude (North Atlantic vs. West African coasts, respectively). Egg-yolk and blood isotope values are correlated in nesting females, indicating that egg analysis is a useful tool for assessing isotope values in these turtles, including adults when not available. Conclusions/Significance Our results complement previous data on turtle movements during the first year following the nesting season, integrating the diet consumed during the year before nesting. We suggest that the French Guiana leatherback population segregates into two distinct isotopic groupings, and highlight the urgent need to determine the feeding habitats of the turtle in the Atlantic in order to protect this species from incidental take by commercial fisheries. Our results also emphasize the use of eggs, a less-invasive sampling material than blood, to assess isotopic data and feeding habits for adult female leatherbacks. PMID:18365003

Potential sources of intra-population variation in the overwintering strategy of painted turtle (Chrysemys picta) hatchlings.

PubMed

Riley, Julia L; Tattersall, Glenn J; Litzgus, Jacqueline D

2014-12-01

Many temperate animals spend half their lives in a non-active, overwintering state, and multiple adaptations have evolved to enable winter survival. One notable vertebrate model is Chrysemys picta, whose hatchlings display dichotomous overwintering strategies: some hatchlings spend their first winter aquatically after nest emergence in the autumn, whereas others overwinter terrestrially within their natal nest with subsequent emergence in the spring. The occurrence of these strategies varies among populations and temporally within populations; however, factors that determine the strategy employed by a nest in nature are unknown. We examined potential factors that influence intra-population variation in the overwintering strategy of C. picta hatchlings over two winters in Algonquin Park, Ontario. We found that environmental factors may be a trigger for the hatchling overwintering strategy: autumn-emerging nests were sloped towards the water and were surrounded by a relatively higher percentage of bare ground compared with spring-emerging nests. Autumn-emerging hatchlings were also relatively smaller. Overwintering strategy was not associated with clutch oviposition sequence, or mammalian or avian predation attempts. Instead, autumn emergence from the nest was associated with the direct mortality threat of predation by sarcophagid fly larvae. Body condition and righting response, measured as proxies of hatchling fitness, did not differ between overwintering strategies. Costs and benefits of overwintering aquatically versus terrestrially in hatchling C. picta are largely unknown, and have the potential to affect population dynamics. Understanding winter survival has great implications for turtle ecology, thus we emphasize areas for future research on dichotomous overwintering strategies in temperate hatchling turtles. © 2014. Published by The Company of Biologists Ltd.

Increased incidence of red imported fire ant (Hymenoptera: Formicidae) presence in loggerhead sea turtle (Testudines: Cheloniidae) nests and observations of hatchling mortality

USGS Publications Warehouse

Parris, L.B.; Lamont, M.M.; Carthy, R.R.

2002-01-01

Hatching sea turtles may be at risk to fire ant predation during egg incubation, and especially at risk once pipped from the egg, prior to hatchling emergence from the nest. In addition to direct mortality, fire ants have the potential to inflict debilitating injuries that may directly affect survival of the young. The increased incidence of red imported fire ant induced mortality and envenomization of loggerhead sea turtle hatchlings on Cape San Blas suggests this invasive ant species may pose a serious threat to the future of this genetically distinct population.

Persistent Leatherback Turtle Migrations Present Opportunities for Conservation

PubMed Central

Shillinger, George L; Palacios, Daniel M; Bailey, Helen; Bograd, Steven J; Swithenbank, Alan M; Gaspar, Philippe; Wallace, Bryan P; Spotila, James R; Paladino, Frank V; Piedra, Rotney; Eckert, Scott A; Block, Barbara A

2008-01-01

Effective transboundary conservation of highly migratory marine animals requires international management cooperation as well as clear scientific information about habitat use by these species. Populations of leatherback turtles (Dermochelys coriacea) in the eastern Pacific have declined by >90% during the past two decades, primarily due to unsustainable egg harvest and fisheries bycatch mortality. While research and conservation efforts on nesting beaches are ongoing, relatively little is known about this population of leatherbacks' oceanic habitat use and migration pathways. We present the largest multi-year (2004–2005, 2005–2006, and 2007) satellite tracking dataset (12,095 cumulative satellite tracking days) collected for leatherback turtles. Forty-six females were electronically tagged during three field seasons at Playa Grande, Costa Rica, the largest extant nesting colony in the eastern Pacific. After completing nesting, the turtles headed southward, traversing the dynamic equatorial currents with rapid, directed movements. In contrast to the highly varied dispersal patterns seen in many other sea turtle populations, leatherbacks from Playa Grande traveled within a persistent migration corridor from Costa Rica, past the equator, and into the South Pacific Gyre, a vast, low-energy, low-productivity region. We describe the predictable effects of ocean currents on a leatherback migration corridor and characterize long-distance movements by the turtles in the eastern South Pacific. These data from high seas habitats will also elucidate potential areas for mitigating fisheries bycatch interactions. These findings directly inform existing multinational conservation frameworks and provide immediate regions in the migration corridor where conservation can be implemented. We identify high seas locations for focusing future conservation efforts within the leatherback dispersal zone in the South Pacific Gyre. PMID:18630987

Winter severity and phenology of spring emergence from the nest in freshwater turtles.

PubMed

Baker, Patrick Joseph; Iverson, John B; Lee, Richard E; Costanzo, Jon P

2010-07-01

Although many species of freshwater turtles emigrate to water soon after hatching, the offspring of some species overwinter on land and move to aquatic habitats in the following spring. Timing of emigration can affect the hatchlings' fitness, but the factors underlying phenology of nest emergence are incompletely understood. We tested the supposition that cold stress imposed during hibernation can influence the timing of nest emergence in three species of turtles in the central USA. In each year of the 6-year study, Chrysemys picta emerged in late March and early April and, on average, these hatchlings left their nests 2 weeks earlier than those of Graptemys geographica and 4 weeks earlier than those of Trachemys scripta. Emergence of conspecific hatchlings from different nests usually occurred over 3-7 weeks, but in some years lasted several additional weeks. Relatively few nests had siblings that emerged on the same day (i.e., synchronously); complete emergence of the typical sibling group required 1 to 2 weeks. In winter, subzero cold occurred with regularity in the nests of all species, though C. picta experienced the lowest temperatures owing to their shallower nests. However, for no species did emergence date or length of the emergence period correlate with winter minimum temperature and, at the level of the individual nest, neither did emergence synchrony or duration. Despite encountering lower temperatures, hatchlings of C. picta emigrated from their nests before those of sympatric species, suggesting that the fitness benefits of early emergence may lead to the improvement of cold-hardiness adaptations in northern populations of turtles.

Winter severity and phenology of spring emergence from the nest in freshwater turtles

NASA Astrophysics Data System (ADS)

Baker, Patrick Joseph; Iverson, John B.; Lee, Richard E.; Costanzo, Jon P.

2010-07-01

Although many species of freshwater turtles emigrate to water soon after hatching, the offspring of some species overwinter on land and move to aquatic habitats in the following spring. Timing of emigration can affect the hatchlings’ fitness, but the factors underlying phenology of nest emergence are incompletely understood. We tested the supposition that cold stress imposed during hibernation can influence the timing of nest emergence in three species of turtles in the central USA. In each year of the 6-year study, Chrysemys picta emerged in late March and early April and, on average, these hatchlings left their nests 2 weeks earlier than those of Graptemys geographica and 4 weeks earlier than those of Trachemys scripta. Emergence of conspecific hatchlings from different nests usually occurred over 3-7 weeks, but in some years lasted several additional weeks. Relatively few nests had siblings that emerged on the same day (i.e., synchronously); complete emergence of the typical sibling group required 1 to 2 weeks. In winter, subzero cold occurred with regularity in the nests of all species, though C. picta experienced the lowest temperatures owing to their shallower nests. However, for no species did emergence date or length of the emergence period correlate with winter minimum temperature and, at the level of the individual nest, neither did emergence synchrony or duration. Despite encountering lower temperatures, hatchlings of C. picta emigrated from their nests before those of sympatric species, suggesting that the fitness benefits of early emergence may lead to the improvement of cold-hardiness adaptations in northern populations of turtles.

Nest inundation from sea-level rise threatens sea turtle population viability.

PubMed

Pike, David A; Roznik, Elizabeth A; Bell, Ian

2015-07-01

Contemporary sea-level rise will inundate coastal habitats with seawater more frequently, disrupting the life cycles of terrestrial fauna well before permanent habitat loss occurs. Sea turtles are reliant on low-lying coastal habitats worldwide for nesting, where eggs buried in the sand remain vulnerable to inundation until hatching. We show that saltwater inundation directly lowers the viability of green turtle eggs (Chelonia mydas) collected from the world's largest green turtle nesting rookery at Raine Island, Australia, which is undergoing enigmatic decline. Inundation for 1 or 3 h reduced egg viability by less than 10%, whereas inundation for 6 h reduced viability by approximately 30%. All embryonic developmental stages were vulnerable to mortality from saltwater inundation. Although the hatchlings that emerged from inundated eggs displayed normal physical and behavioural traits, hypoxia during incubation could influence other aspects of the physiology or behaviour of developing embryos, such as learning or spatial orientation. Saltwater inundation can directly lower hatching success, but it does not completely explain the consistently low rates of hatchling production observed on Raine Island. More frequent nest inundation associated with sea-level rise will increase variability in sea turtle hatching success spatially and temporally, due to direct and indirect impacts of saltwater inundation on developing embryos.

Nest inundation from sea-level rise threatens sea turtle population viability

PubMed Central

Pike, David A.; Roznik, Elizabeth A.; Bell, Ian

2015-01-01

Contemporary sea-level rise will inundate coastal habitats with seawater more frequently, disrupting the life cycles of terrestrial fauna well before permanent habitat loss occurs. Sea turtles are reliant on low-lying coastal habitats worldwide for nesting, where eggs buried in the sand remain vulnerable to inundation until hatching. We show that saltwater inundation directly lowers the viability of green turtle eggs (Chelonia mydas) collected from the world's largest green turtle nesting rookery at Raine Island, Australia, which is undergoing enigmatic decline. Inundation for 1 or 3 h reduced egg viability by less than 10%, whereas inundation for 6 h reduced viability by approximately 30%. All embryonic developmental stages were vulnerable to mortality from saltwater inundation. Although the hatchlings that emerged from inundated eggs displayed normal physical and behavioural traits, hypoxia during incubation could influence other aspects of the physiology or behaviour of developing embryos, such as learning or spatial orientation. Saltwater inundation can directly lower hatching success, but it does not completely explain the consistently low rates of hatchling production observed on Raine Island. More frequent nest inundation associated with sea-level rise will increase variability in sea turtle hatching success spatially and temporally, due to direct and indirect impacts of saltwater inundation on developing embryos. PMID:26587269

Phenology of marine turtle nesting revealed by statistical model of the nesting season.

PubMed

Girondot, Marc; Rivalan, Philippe; Wongsopawiro, Ronald; Briane, Jean-Paul; Hulin, Vincent; Caut, Stéphane; Guirlet, Elodie; Godfrey, Matthew H

2006-08-31

Marine turtles deposit their eggs on tropical or subtropical beaches during discrete nesting seasons that span several months. The number and distribution of nests laid during a nesting season provide vital information on various aspects of marine turtle ecology and conservation. In the case of leatherback sea turtles nesting in French Guiana, we developed a mathematical model to explore the phenology of their nesting season, derived from an incomplete nest count dataset. We detected 3 primary components in the nest distribution of leatherbacks: an overall shape that corresponds to the arrival and departure of leatherback females in the Guianas region, a sinusoidal pattern with a period of approximately 10 days that is related to physiological constraints of nesting female leatherbacks, and a sinusoidal pattern with a period of approximately 15 days that likely reflects the influence of spring high tides on nesting female turtles. The model proposed here offers a variety of uses for both marine turtles and also other taxa when individuals are observed in a particular location for only part of the year.

Physical Effects of Beach Nourishment on Sea Turtle Nesting, Delray Beach, Florida. Environmental Impact Research Program.

DTIC Science & Technology

1987-10-01

Turtles (Cheidra serptina)," Canadian Journal of Zoology, Vol 62, pp 2401-2403. Hendrickson, J. R. 1958. " The Green Turtle , CheZonia mydas (Linn.), in...sea turtle nests in the United States are located in beaches that have been nourished or renourished. Questions have been raised about how physical...changes In the beaches will affect the nesting activities of these sea turtles that use nourished beaches for nesting.’) This study was conducted to

Anti-predator meshing may provide greater protection for sea turtle nests than predator removal.

PubMed

O'Connor, Julie M; Limpus, Colin J; Hofmeister, Kate M; Allen, Benjamin L; Burnett, Scott E

2017-01-01

The problem of how to protect sea turtle nests from terrestrial predators is of worldwide concern. On Queensland's southern Sunshine Coast, depredation of turtle nests by the introduced European red fox (Vulpes vulpes) has been recorded as the primary terrestrial cause of egg and hatchling mortality. We investigated the impact of foxes on the nests of the loggerhead turtle (Caretta caretta) and occasional green turtle (Chelonia mydas) over ten nesting seasons. Meshing of nests with fox exclusion devices (FEDs) was undertaken in all years accompanied by lethal fox control in the first five-year period, but not in the second five-year period. Lethal fox control was undertaken in the study area from 2005 to February 2010, but foxes still breached 27% (range19-52%) of turtle nests. In the second five-year period, despite the absence of lethal fox control, the average percentage of nests breached was less than 3% (range 0-4%). Comparison of clutch depredation rates in the two five-year periods demonstrated that continuous nest meshing may be more effective than lethal fox control in mitigating the impact of foxes on turtle nests. In the absence of unlimited resources available for the eradication of exotic predators, the use of FEDs and the support and resourcing of a dedicated volunteer base can be considered an effective turtle conservation tool on some beaches.

Western Pond Turtle Head-starting and Reintroduction; 2004-2005 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Leuven, Susan; Allen, Harriet; Slavin, Kate

This report covers the results of the western pond turtle head-starting and reintroduction project for the period of October 2004-September 2005. Wild hatchling western pond turtles from the Columbia River Gorge were reared at the Woodland Park and Oregon Zoos in 2004 and 2005 as part of the recovery effort for this Washington State endangered species. The objective of the program is to reduce losses to introduced predators like bullfrogs and largemouth bass by raising the hatchlings to a size where they are too large to be eaten by most of these predators. Thirty-five turtles were placed at the Woodlandmore » Park Zoo and 53 at the Oregon Zoo. Of these, 77 head-started juvenile turtles were released at three sites in the Columbia Gorge in 2005. Four were held back to attain more growth in captivity. Eleven were released at the Klickitat ponds, 22 at the Klickitat lake, 39 at the Skamania site, and 5 at Pierce National Wildlife Refuge (NWR). This brought the total number of head-start turtles released since 1991 to 257 for the Klickitat ponds, 136 for the Klickitat lake, 206 for the Skamania pond complex, and 255 at Pierce NWR. In 2005, 34 females from the two Columbia Gorge populations were equipped with transmitters and monitored for nesting activity. Twenty-four nests were located and protected; these produced 90 hatchlings. The hatchlings were collected in September and transported to the Oregon and Woodland Park zoos for rearing in the head-start program. During the 2005 field season trapping effort, 486 western pond turtles were captured in the Columbia Gorge, including 430 previously head-started turtles. These recaptures, together with confirmed nesting by head-start females and visual resightings, indicate the program is succeeding in boosting juvenile recruitment to increase the populations. Records were also collected on 216 individual painted turtles captured in 2005 during trapping efforts at Pierce NWR, to gather baseline information on this native population. Bonneville Power Administration (BPA) funded approximately 75% of program activities in the Columbia River Gorge from October 2004 through September 2005.« less

Sea turtle species vary in their susceptibility to tropical cyclones.

PubMed

Pike, David A; Stiner, John C

2007-08-01

Severe climatic events affect all species, but there is little quantitative knowledge of how sympatric species react to such situations. We compared the reproductive seasonality of sea turtles that nest sympatrically with their vulnerability to tropical cyclones (in this study, "tropical cyclone" refers to tropical storms and hurricanes), which are increasing in severity due to changes in global climate. Storm surges significantly decreased reproductive output by lowering the number of nests that hatched and the number of hatchlings that emerged from nests, but the severity of this effect varied by species. Leatherback turtles (Dermochelys coriacea) began nesting earliest and most offspring hatched before the tropical cyclone season arrived, resulting in little negative effect. Loggerhead turtles (Caretta caretta) nested intermediately, and only nests laid late in the season were inundated with seawater during storm surges. Green turtles (Chelonia mydas) nested last, and their entire nesting season occurred during the tropical cyclone season; this resulted in a majority (79%) of green turtle nests incubating in September, when tropical cyclones are most likely to occur. Since this timing overlaps considerably with the tropical cyclone season, the developing eggs and nests are extremely vulnerable to storm surges. Increases in the severity of tropical cyclones may cause green turtle nesting success to worsen in the future. However, published literature suggests that loggerhead turtles are nesting earlier in the season and shortening their nesting seasons in response to increasing sea surface temperatures caused by global climate change. This may cause loggerhead reproductive success to improve in the future because more nests will hatch before the onset of tropical cyclones. Our data clearly indicate that sympatric species using the same resources are affected differently by tropical cyclones due to slight variations in the seasonal timing of nesting, a key life history process.

A continuation of base-line studies for environmentally monitoring Space Transportation Systems (STS) at John F. Kennedy Space Center. Volume 4: Threatened and endangered species of the Kennedy Space Center. Part 1: Marine turtle studies

NASA Technical Reports Server (NTRS)

Ehrhart, L. M.

1980-01-01

The status of marine turtle populations in the KSC area was studied using data from previous results from ground and aerial surveillance conducted from 1976 to April 1979. During ground surveillance, various data were recorded on emergent turtles such as: species, weight, tag number (if previously tagged), time discovered, activity at discovery and the location of discovery. Observations were also made on nesting and reproductive characteristics, population estimates, immigration and emigration and growth rate of the turtles. Mortality studies were additionally made and autopsies performed on dead turtles found in the area. It is concluded that further mortality documentation should be done just prior to and just after a future space launch operation in order to accurately assess the cause and effect relationship of such a launch on the turtle population.

Plasma steroid profiles in nesting loggerhead turtles (Caretta caretta) in Queensland, Australia: relationship to nesting episode and season.

PubMed

Whittier, J M; Corrie, F; Limpus, C

1997-04-01

Plasma levels of four hormones-progesterone (P), testosterone (T), estradiol 17-beta (E2), and corticosterone (B)-were measured in samples taken from nesting female loggerhead turtles (Caretta caretta) by using specific radioimmunoassays. Samples were taken in an early, middle, or late period during the summer nesting season from females at first, second, third, or > fourth nesting episodes, defined as successive within-season nesting events, at Mon Repos Beach, Queensland, Australia. Data on individual patterns of nesting, collected over the past 20 years by the Queensland Turtle Research Project, and the seasonal nesting data, were analyzed with respect to influences on hormonal profiles. Circulating levels of E2 were mostly undetectable, suggesting either that this estrogen is not produced at this time of nesting, or that, perhaps, another estrogen may be present that is not detected by the specific radioimmunoassay. P, T, and B profiles in the nesting females were associated with the individual turtles' progression through successive nesting episodes, with a marked decline in all three hormones by the last (> 4) nesting episode of the season. Nesting episode accounted for significant changes that were related to season, in that nesting episode and season were significantly correlated. These patterns were observed in the population, when singly sampled at each time period or nesting episode, and in individual females sampled repeatedly over time. Moreover, T and B were highly and significantly correlated in females at all nesting episodes and time periods, and in the singly and repeatedly sampled females. The magnitude of change in T and B over time was also highly and significantly correlated in repeatedly sampled females. Together these results suggest the hypothesis that T and B interact over the period of successive nesting and may be involved in reproductive functions such as the mobilization of reserves for egg production in C. caretta.

Maternal health status correlates with nest success of leatherback sea turtles (Dermochelys coriacea) from Florida.

PubMed

Perrault, Justin R; Miller, Debra L; Eads, Erica; Johnson, Chris; Merrill, Anita; Thompson, Larry J; Wyneken, Jeanette

2012-01-01

Of the seven sea turtle species, the critically endangered leatherback sea turtle (Dermochelys coriacea) exhibits the lowest and most variable nest success (i.e., hatching success and emergence success) for reasons that remain largely unknown. In an attempt to identify or rule out causes of low reproductive success in this species, we established the largest sample size (n = 60-70 for most values) of baseline blood parameters (protein electrophoresis, hematology, plasma biochemistry) for this species to date. Hematologic, protein electrophoretic and biochemical values are important tools that can provide information regarding the physiological condition of an individual and population health as a whole. It has been proposed that the health of nesting individuals affects their reproductive output. In order to establish correlations with low reproductive success in leatherback sea turtles from Florida, we compared maternal health indices to hatching success and emergence success of their nests. As expected, hatching success (median = 57.4%) and emergence success (median = 49.1%) in Floridian leatherbacks were low during the study period (2007-2008 nesting seasons), a trend common in most nesting leatherback populations (average global hatching success = ∼50%). One protein electrophoretic value (gamma globulin protein) and one hematologic value (red blood cell count) significantly correlated with hatching success and emergence success. Several maternal biochemical parameters correlated with hatching success and/or emergence success including alkaline phosphatase activity, blood urea nitrogen, calcium, calcium:phosphorus ratio, carbon dioxide, cholesterol, creatinine, and phosphorus. Our results suggest that in leatherbacks, physiological parameters correlate with hatching success and emergence success of their nests. We conclude that long-term and comparative studies are needed to determine if certain individuals produce nests with lower hatching success and emergence success than others, and if those individuals with evidence of chronic suboptimal health have lower reproductive success.

Maternal Health Status Correlates with Nest Success of Leatherback Sea Turtles (Dermochelys coriacea) from Florida

PubMed Central

Perrault, Justin R.; Miller, Debra L.; Eads, Erica; Johnson, Chris; Merrill, Anita; Thompson, Larry J.; Wyneken, Jeanette

2012-01-01

Of the seven sea turtle species, the critically endangered leatherback sea turtle (Dermochelys coriacea) exhibits the lowest and most variable nest success (i.e., hatching success and emergence success) for reasons that remain largely unknown. In an attempt to identify or rule out causes of low reproductive success in this species, we established the largest sample size (n = 60–70 for most values) of baseline blood parameters (protein electrophoresis, hematology, plasma biochemistry) for this species to date. Hematologic, protein electrophoretic and biochemical values are important tools that can provide information regarding the physiological condition of an individual and population health as a whole. It has been proposed that the health of nesting individuals affects their reproductive output. In order to establish correlations with low reproductive success in leatherback sea turtles from Florida, we compared maternal health indices to hatching success and emergence success of their nests. As expected, hatching success (median = 57.4%) and emergence success (median = 49.1%) in Floridian leatherbacks were low during the study period (2007–2008 nesting seasons), a trend common in most nesting leatherback populations (average global hatching success = ∼50%). One protein electrophoretic value (gamma globulin protein) and one hematologic value (red blood cell count) significantly correlated with hatching success and emergence success. Several maternal biochemical parameters correlated with hatching success and/or emergence success including alkaline phosphatase activity, blood urea nitrogen, calcium, calcium∶phosphorus ratio, carbon dioxide, cholesterol, creatinine, and phosphorus. Our results suggest that in leatherbacks, physiological parameters correlate with hatching success and emergence success of their nests. We conclude that long-term and comparative studies are needed to determine if certain individuals produce nests with lower hatching success and emergence success than others, and if those individuals with evidence of chronic suboptimal health have lower reproductive success. PMID:22359635

Genetic structure of Florida green turtle rookeries as indicated by mitochondrial DNA control region sequences

USGS Publications Warehouse

Shamblin, Brian M.; Bagley, Dean A.; Ehrhart, Llewellyn M.; Desjardin, Nicole A.; Martin, R. Erik; Hart, Kristen M.; Naro-Maciel, Eugenia; Rusenko, Kirt; Stiner, John C.; Sobel, Debra; Johnson, Chris; Wilmers, Thomas; Wright, Laura J.; Nairn, Campbell J.

2014-01-01

Green turtle (Chelonia mydas) nesting has increased dramatically in Florida over the past two decades, ranking the Florida nesting aggregation among the largest in the Greater Caribbean region. Individual beaches that comprise several hundred kilometers of Florida’s east coast and Keys support tens to thousands of nests annually. These beaches encompass natural to highly developed habitats, and the degree of demographic partitioning among rookeries was previously unresolved. We characterized the genetic structure of ten Florida rookeries from Cape Canaveral to the Dry Tortugas through analysis of 817 base pair mitochondrial DNA (mtDNA) control region sequences from 485 nesting turtles. Two common haplotypes, CM-A1.1 and CM-A3.1, accounted for 87 % of samples, and the haplotype frequencies were strongly partitioned by latitude along Florida’s Atlantic coast. Most genetic structure occurred between rookeries on either side of an apparent genetic break in the vicinity of the St. Lucie Inlet that separates Hutchinson Island and Jupiter Island, representing the finest scale at which mtDNA structure has been documented in marine turtle rookeries. Florida and Caribbean scale analyses of population structure support recognition of at least two management units: central eastern Florida and southern Florida. More thorough sampling and deeper sequencing are necessary to better characterize connectivity among Florida green turtle rookeries as well as between the Florida nesting aggregation and others in the Greater Caribbean region.

Climate and predation dominate juvenile and adult recruitment in a turtle with temperature-dependent sex determination.

PubMed

Schwanz, Lisa E; Spencer, Ricky-John; Bowden, Rachel M; Janzen, Fredric J

2010-10-01

Conditions experienced early in life can influence phenotypes in ecologically important ways, as exemplified by organisms with environmental sex determination. For organisms with temperature-dependent sex determination (TSD), variation in nest temperatures induces phenotypic variation that could impact population growth rates. In environments that vary over space and time, how does this variation influence key demographic parameters (cohort sex ratio and hatchling recruitment) in early life stages of populations exhibiting TSD? We leverage a 17-year data set on a population of painted turtles, Chrysemys picta, to investigate how spatial variation in nest vegetation cover and temporal variation in climate influence early life-history demography. We found that spatial variation in nest cover strongly influenced nest temperature and sex ratio, but was not correlated with clutch size, nest predation, total nest failure, or hatching success. Temporal variation in climate influenced percentage of total nest failure and cohort sex ratio, but not depredation rate, mean clutch size, or mean hatching success. Total hatchling recruitment in a year was influenced primarily by temporal variation in climate-independent factors, number of nests constructed, and depredation rate. Recruitment of female hatchlings was determined by stochastic variation in nest depredation and annual climate and also by the total nest production. Overall population demography depends more strongly on annual variation in climate and predation than it does on the intricacies of nest-specific biology. Finally, we demonstrate that recruitment of female hatchlings translates into recruitment of breeding females into the population, thus linking climate (and other) effects on early life stages to adult demographics.

The Influences of Soil Characteristics on Nest-Site Selection in Painted Turtles (Chrysemys picta)

NASA Astrophysics Data System (ADS)

Page, R.

2017-12-01

A variety of animals dig nests and lay their eggs in soil, leaving them to incubate and hatch without assistance from the parents. Nesting habitat is important for these organisms many of which exhibit temperature dependent sex determination (TSD) whereby the incubation temperature determines the sex of each hatchling. However, suitable nesting habitat may be limited due to anthropogenic activities and global temperature increases. Soil thermal properties are critical to these organisms and are positively correlated with water retention and soil carbon; carbon-rich soils result in higher incubation temperatures. We investigated nest-site selection in painted turtles (Chrysemys picta) inhabiting an anthropogenic pond in south central Pennsylvania. We surveyed for turtle nests and documented location, depth, width, temperature, canopy coverage, clutch size, and hatch success for a total of 31 turtle nests. To address the influence of soil carbon and particle size on nest selection, we analyzed samples collected from: 1) actual nests that were depredated, 2) false nests, incomplete nests aborted during digging prior to nest completion, and 3) randomized locations. Soil samples were separated into coarse, medium, and fine grain size fractions through a stack of sieves. Samples were combusted in a total carbon analyzer to measure weight percent organic carbon. We found that anthropogenic activity at this site has created homogenous, sandy, compacted soils at the uppermost layer that may limit females' access to appropriate nesting habitat. Turtle nesting activity was limited to a linear region north of the pond and was constrained by an impassable rail line. Relative to other studies, turtle nests were notably shallow (5.8±0.9 cm) and placed close to the pond. Compared to false nests and random locations, turtle-selected sites averaged greater coarse grains (35% compared to 20.24 and 20.57%) and less fine grains (47% compared to 59 and 59, respectively). Despite remarkably high soil carbon along the rail line (47.08%) turtles nested here with slightly higher hatch success. We suggest that the turtles are limited to sandy, compact soils with low heat capacities and may compensate for this by also nesting adjacent to the rail line where high soil carbon could increase incubation temperatures.

Application of topography survey on the green sea turtle (Chelonia mydas) conservation

NASA Astrophysics Data System (ADS)

Fan, Yuan-Yu; Lo, Liu-Chih; Peng, Kuan-Chieh

2017-04-01

Taiwan is located in the Western Pacific monsoon region, typhoon is one of the common natural disasters. Taiwan is hit by typhoons 6 times on average each year, and 2016 have 5. Typhoon not only caused the loss of nature environment in Taiwan but also decreased the endangered species- green sea turtle's breeding success rate. In Wangan island, Penghu, green sea turtle nesting beach's slop is too steep to form the dune cliff, block the way which green sea turtle should nesting above the vegetation line. Nesting under the dune cliff is disturbed easily by the swell from typhoon, Leading to the whole nest was emptied or hatching rate decreased due to water content changed. In order to reduce the threat of typhoon on the green sea turtle, and promote the success of green sea turtle reproduction, we used LiDAR(Light Detection And Ranging) to monitor the topographic change of the green sea turtle nesting habitat and compare the invasion and deposition of the green sea turtle nests before and after the occurrence of typhoons. The results showed that the breeding success rate before the typhoon (2016/09/12) was 93%, which was not affected by the swell. The breeding success rate at the higher position after the typhoon was 95%, and under the dune cliff, 10 nests reproduction failed due to the swell changing the sand layer thickness. The production of dune cliffs is formed by the roots of coastal sand-fixation plants. In the past, the residents collected the coastal plants for fuel, after collecting, sparse vegetation is good to form the flat beach, and to promote green sea turtle nesting on the higher position from the disturbance of typhoon. In the future, to protect the success of green sea turtle's reproduction, should increase the human intervention that disturb the nesting beach's vegetation appropriately, Or cutting the roots directly to reduce the dune cliffs before the nesting season, help the green sea turtle nesting in a higher beach, improve the green sea turtle's breeding success rate.

Climate change and temperature-dependent sex determination: can individual plasticity in nesting phenology prevent extreme sex ratios?

PubMed

Schwanz, Lisa E; Janzen, Fredric J

2008-01-01

Under temperature-dependent sex determination (TSD), temperatures experienced by embryos during development determine the sex of the offspring. Consequently, populations of organisms with TSD have the potential to be strongly impacted by climatic warming that could bias offspring sex ratio, a fundamental demographic parameter involved in population dynamics. Moreover, many taxa with TSD are imperiled, so research on this phenomenon, particularly long-term field study, has assumed great urgency. Recently, turtles with TSD have joined the diverse list of taxa that have demonstrated population-level changes in breeding phenology in response to recent climate change. This raises the possibility that any adverse impacts of climate change on populations may be alleviated by individual plasticity in nesting phenology. Here, we examine data from a long-term study on a population of painted turtles (Chrysemys picta) to determine whether changes in phenology are due to individual plasticity and whether individual plasticity in the timing of nesting has the capacity to offset the sex ratio effects of a rise in climatic temperature. We find that individual females show plasticity in the date of first nesting each year, and that this plasticity depends on the climate from the previous winter. First nesting date is not repeatable within individuals, suggesting that it would not respond to selection. Sex ratios of hatchlings within a nest declined nonsignificantly over the nesting season. However, small increases in summer temperature had a much stronger effect on nest sex ratios than did laying nests earlier in the season. For this and other reasons, it seems unlikely that individual plasticity in the timing of nesting will offset the effects of climate change on sex ratios in this population, and we hypothesize that this conclusion applies to other populations with TSD.

Changes in plasma levels of adrenaline, noradrenaline, glucose, lactate and CO2 in the green turtle, Chelonia mydas, during peak period of nesting.

PubMed

Alkindi, A Y A; Al-Habsi, A A; Mahmoud, I Y

2008-02-01

Plasma concentrations of stress hormones [adrenaline (ADR), noradrenaline (NR)], lactate, glucose and CO2 were monitored during peak nesting period (May-October) at different phases of nesting in the green turtle, Chelonia mydas. These include, emergence from sea, excavating body and nest chambers, oviposition, covering and camouflaging the nest and then returning to sea. Turtles that completed all phases of nesting including oviposition before returning to sea were considered "successful" turtles, while those that completed all phases but failed to lay their eggs were "unsuccessful". Blood samples were taken from the cervical sinus within 5min of capture to avoid stress due to handling. The turtles were usually sampled for blood between 20:00 and 1:00h of nesting time to ensure uniformity in the sampling. Plasma ADR and NR values were highly significant (P<0.001) in successful turtles over emergence, excavating and unsuccessful turtles. Plasma glucose levels remained stable throughout the nesting phases while lactate levels were significantly higher in successful turtles over the other phases (P<0.05) which signifies anaerobic metabolism during nesting. Plasma CO2 values were negatively correlated with ADR and NR (r=-0.258, P=0.03; r=-0.304, P=0.010), respectively. Hematocrit was significantly higher in successful phase (P<0.05) compared to other phases, and this may signify a higher degree of stress in successful turtles. Body temperature were significantly lower (P<0.005) in the excavating phase compared to the other three phases. Overall, body temperatures were lower than sand temperatures around the nest, which may indicate a behavioral thermoregulation used by the turtles during nesting. This information will be of value to the ongoing conservation program at Ras Al-Hadd Reserve in the Sultanate of Oman.

Effectiveness of nest site restoration for the endangered northern map turtle : report 2 : use of artificial nesting sites and wildlife exclusion fences to enhance nesting success : research summary.

DOT National Transportation Integrated Search

2016-10-01

The Northern Map Turtle, is a state Endangered Species, found only in the : lower Susquehanna River in Maryland. The only area where nests of this : species are not heavily impacted by predators is in the town of Port Deposit. : However, turtles nest...

The effects of large beach debris on nesting sea turtles

USGS Publications Warehouse

Fujisaki, Ikuko; Lamont, Margaret M.

2016-01-01

A field experiment was conducted to understand the effects of large beach debris on sea turtle nesting behavior as well as the effectiveness of large debris removal for habitat restoration. Large natural and anthropogenic debris were removed from one of three sections of a sea turtle nesting beach and distributions of nests and false crawls (non-nesting crawls) in pre- (2011–2012) and post- (2013–2014) removal years in the three sections were compared. The number of nests increased 200% and the number of false crawls increased 55% in the experimental section, whereas a corresponding increase in number of nests and false crawls was not observed in the other two sections where debris removal was not conducted. The proportion of nest and false crawl abundance in all three beach sections was significantly different between pre- and post-removal years. The nesting success, the percent of successful nests in total nesting attempts (number of nests + false crawls), also increased from 24% to 38%; however the magnitude of the increase was comparably small because both the number of nests and false crawls increased, and thus the proportion of the nesting success in the experimental beach in pre- and post-removal years was not significantly different. The substantial increase in sea turtle nesting activities after the removal of large debris indicates that large debris may have an adverse impact on sea turtle nesting behavior. Removal of large debris could be an effective restoration strategy to improve sea turtle nesting.

Movements and Habitat-Use of Loggerhead Sea Turtles in the Northern Gulf of Mexico during the Reproductive Period

PubMed Central

Hart, Kristen M.; Lamont, Margaret M.; Sartain, Autumn R.; Fujisaki, Ikuko; Stephens, Brail S.

2013-01-01

Nesting strategies and use of important in-water habitats for far-ranging marine turtles can be determined using satellite telemetry. Because of a lack of information on habitat-use by marine turtles in the northern Gulf of Mexico, we used satellite transmitters in 2010 through 2012 to track movements of 39 adult female breeding loggerhead turtles (Caretta caretta) tagged on nesting beaches at three sites in Florida and Alabama. During the nesting season, recaptured turtles emerged to nest 1 to 5 times, with mean distance between emergences of 27.5 km; however, several turtles nested on beaches separated by ∼250 km within a single season. Mean total distances traveled throughout inter-nesting periods for all turtles was 1422.0±930.8 km. In-water inter-nesting sites, delineated using 50% kernel density estimation (KDE), were located a mean distance of 33.0 km from land, in water with mean depth of −31.6 m; other in-water inter-nesting sites, delineated using minimum convex polygon (MCP) approach, were located a mean 13.8 km from land and in water with a mean depth of −15.8 m. Mean size of in-water inter-nesting habitats were 61.9 km2 (50% KDEs, n = 10) and 741.4 km2 (MCPs, n = 30); these areas overlapped significantly with trawling and oil and gas extraction activities. Abundance estimates for this nesting subpopulation may be inaccurate in light of how much spread there is between nests of the same individual. Further, our results also have consequences for critical habitat designations for northern Gulf loggerheads, as protection of one nesting beach would not encompass the entire range used by turtles during breeding seasons. PMID:23843971

Movements and habitat-use of loggerhead sea turtles in the northern Gulf of Mexico during the reproductive period

USGS Publications Warehouse

Hart, Kristen M.; Lamont, Margaret M.; Sartain-Iverson, Autumn R.; Fujisaki, Ikuko; Stephens, Brail S.

2013-01-01

Nesting strategies and use of important in-water habitats for far-ranging marine turtles can be determined using satellite telemetry. Because of a lack of information on habitat-use by marine turtles in the northern Gulf of Mexico, we used satellite transmitters in 2010 through 2012 to track movements of 39 adult female breeding loggerhead turtles (Caretta caretta) tagged on nesting beaches at three sites in Florida and Alabama. During the nesting season, recaptured turtles emerged to nest 1 to 5 times, with mean distance between emergences of 27.5 km; however, several turtles nested on beaches separated by ~250 km within a single season. Mean total distances traveled throughout inter-nesting periods for all turtles was 1422.0±930.8 km. In-water inter-nesting sites, delineated using 50% kernel density estimation (KDE), were located a mean distance of 33.0 km from land, in water with mean depth of −31.6 m; other in-water inter-nesting sites, delineated using minimum convex polygon (MCP) approach, were located a mean 13.8 km from land and in water with a mean depth of −15.8 m. Mean size of in-water inter-nesting habitats were 61.9 km2 (50% KDEs, n = 10) and 741.4 km2 (MCPs, n = 30); these areas overlapped significantly with trawling and oil and gas extraction activities. Abundance estimates for this nesting subpopulation may be inaccurate in light of how much spread there is between nests of the same individual. Further, our results also have consequences for critical habitat designations for northern Gulf loggerheads, as protection of one nesting beach would not encompass the entire range used by turtles during breeding seasons.

Movements and habitat-use of loggerhead sea turtles in the northern Gulf of Mexico during the reproductive period.

PubMed

Hart, Kristen M; Lamont, Margaret M; Sartain, Autumn R; Fujisaki, Ikuko; Stephens, Brail S

2013-01-01

Nesting strategies and use of important in-water habitats for far-ranging marine turtles can be determined using satellite telemetry. Because of a lack of information on habitat-use by marine turtles in the northern Gulf of Mexico, we used satellite transmitters in 2010 through 2012 to track movements of 39 adult female breeding loggerhead turtles (Caretta caretta) tagged on nesting beaches at three sites in Florida and Alabama. During the nesting season, recaptured turtles emerged to nest 1 to 5 times, with mean distance between emergences of 27.5 km; however, several turtles nested on beaches separated by ~250 km within a single season. Mean total distances traveled throughout inter-nesting periods for all turtles was 1422.0 ± 930.8 km. In-water inter-nesting sites, delineated using 50% kernel density estimation (KDE), were located a mean distance of 33.0 km from land, in water with mean depth of -31.6 m; other in-water inter-nesting sites, delineated using minimum convex polygon (MCP) approach, were located a mean 13.8 km from land and in water with a mean depth of -15.8 m. Mean size of in-water inter-nesting habitats were 61.9 km(2) (50% KDEs, n = 10) and 741.4 km(2) (MCPs, n = 30); these areas overlapped significantly with trawling and oil and gas extraction activities. Abundance estimates for this nesting subpopulation may be inaccurate in light of how much spread there is between nests of the same individual. Further, our results also have consequences for critical habitat designations for northern Gulf loggerheads, as protection of one nesting beach would not encompass the entire range used by turtles during breeding seasons.

Effect of tidal overwash on the embryonic development of leatherback turtles in French Guiana.

PubMed

Caut, Stéphane; Guirlet, Elodie; Girondot, Marc

2010-05-01

In marine turtles, the physical conditions experienced by eggs during incubation affect embryonic development. In the leatherback, hatching success is known to be low in relation to other marine turtles as a result of high embryonic mortality. Moreover, the hatching success on Yalimapo in French Guiana, one major nesting beach for this species, is lower compared to other nesting sites. We assessed the rate of leatherback turtle embryonic mortality in order to investigate the tolerance of leatherback turtle clutches laid on Yalimapo beach to tidal overwash, and we highlight causes of poor hatching success. Of the 89 nests studied, 27 were overlapped by tide at least once during the incubation period (of which five nests were lost by erosion). The hatching success was on average significantly lower in overwashed nests than in non-overwashed, highlighting the existence of embryonic developmental arrest linked to tidal inundation. The stages of developmental arrest and their proportion are linked with time, frequency and level of overwash events. In the context of global warming and associated sea-level rise, understanding the detrimental effect of tidal inundation on the development of marine turtle nests is of interest in nesting sites where turtles are likely to be forced to nest closer to the tide line, thus exposing their nests to greater risk of nest overlap with sea and tidal inundation. Copyright 2009 Elsevier Ltd. All rights reserved.

Nest-site characteristics of Glyptemys muhlenbergii (Bog Turtle) in New Jersey and Pennsylvania

USGS Publications Warehouse

Zappalorti, Robert T.; Lovich, Jeffrey E.; Farrell, Ray F.; Torocco, Michael E.

2015-01-01

Nest-site selection can affect both the survival and fitness of female turtles and their offspring. In many turtle species, the nest environment determines the thermal regime during incubation, length of incubation period, sex ratio of the hatchlings, and exposure to predators and other forms of mortality for both mothers and their offspring. Between 1974 and 2012, we collected detailed data on habitat variables at 66 Glyptemys muhlenbergii (Bog Turtle) nests in 9 different bogs, fens, and wetland complexes in New Jersey and Pennsylvania. The nests had a mean elevation above the substrate of 8.2 cm, and many were shallow and located in raised tussocks of grass or sedges. Females covered most nests, but we also observed partially or completely uncovered eggs. Some females deposited eggs in communal nests; we found 4 nests with 2 separate clutches, and 2 nests with 3 clutches. Principal component analysis confirmed the importance of cover and vegetation to nest-site selection in this species. Availability of open, shade-free, wet nesting areas is an important habitat requirement for Bog Turtles.

Reproductive biology and genetic diversity of the green turtle (Chelonia mydas) in Vamizi island, Mozambique.

PubMed

Anastácio, Rita; Santos, Camila; Lopes, Cardoso; Moreira, Helena; Souto, Luis; Ferrão, Jorge; Garnier, Julie; Pereira, Mário J

2014-01-01

Vamizi, an Island located in the Western Indian Ocean, is visited by a small and not fully characterized green turtle (Chelonia mydas (L.)) population. This population is threatened by natural hazards and several human activities, which are used to identify conservation priorities for marine turtles. It was our aim to contribute to the knowledge of marine turtles that nest in Vamizi, with respect to its regional management, and to an area that may possibly be included on the UNESCO World Heritage List due to its potential Outstanding Universal Value. Here, we evaluate the nesting parameters (incubation period, clutch size, hatching and emergence successes rates) and patterns over an 8-year (2003 - 2010) conservation program. We also present the results of genetic diversity based on the analysis of approximately an 850 pb fragment of the mitochondrial DNA control region. We found that Vamizi beaches host a small number of nesting females, approximately 52 per year, but these have shown a reduction in their length. High hatching success (88.5 ± SD 17.2%, N = 649), emergence success rates (84.5 ± SD 20.4%, N = 649) were observed, and genetic diversity (N = 135), with 11 haplotypes found (7 new). It was also observed, in the later years of this study, a reduction in the incubation period, a dislocation of the nesting peak activity and an increase in the number of flooded nests and an increase of the number of nests in areas with lower human activity. Some resilience and behavioral plasticity seems to occur regarding human territory occupancy and climate changes. However, regardless of the results, aspects like what seems to be the reduction of some cohorts, the number of flooded nests and the diminishing of the incubation period (East and South facing beaches), show that conservation efforts have to be improved.

Distorting Gene Pools by Conservation: Assessing the Case of Doomed Turtle Eggs

NASA Astrophysics Data System (ADS)

Mrosovsky, N.

2006-10-01

Sea turtles have a high reproductive output and high mortality at early stages of the life cycle. In particular, many nests are laid below or close to high tide lines, and subsequently large numbers of eggs may be inundated and destroyed. A common conservation procedure is to relocate such doomed eggs to higher ground. This article examines this practice in the light of recent data revealing that some individual turtles tend to nest relatively near the water and others relatively higher up the beach. Discussion is focused on the question of why apparently poor placement of nests has not been selected against. Comparison between the ecology of leatherback and hawksbill turtle nesting beaches suggests that predictability of environmental conditions on the nesting beaches has an important influence on patterns of nest-site selection. Options are outlined for the management of nesting beaches where a high proportion of turtle eggs is subject to destruction by flooding.

Distorting gene pools by conservation: Assessing the case of doomed turtle eggs.

PubMed

Mrosovsky, N

2006-10-01

Sea turtles have a high reproductive output and high mortality at early stages of the life cycle. In particular, many nests are laid below or close to high tide lines, and subsequently large numbers of eggs may be inundated and destroyed. A common conservation procedure is to relocate such doomed eggs to higher ground. This article examines this practice in the light of recent data revealing that some individual turtles tend to nest relatively near the water and others relatively higher up the beach. Discussion is focused on the question of why apparently poor placement of nests has not been selected against. Comparison between the ecology of leatherback and hawksbill turtle nesting beaches suggests that predictability of environmental conditions on the nesting beaches has an important influence on patterns of nest-site selection. Options are outlined for the management of nesting beaches where a high proportion of turtle eggs is subject to destruction by flooding.

Changes of loggerhead turtle (Caretta caretta) dive behavior associated with tropical storm passage during the inter-nesting period.

PubMed

Wilson, Maria; Tucker, Anton D; Beedholm, Kristian; Mann, David A

2017-10-01

To improve conservation strategies for threatened sea turtles, more knowledge on their ecology, behavior, and how they cope with severe and changing weather conditions is needed. Satellite and animal motion datalogging tags were used to study the inter-nesting behavior of two female loggerhead turtles in the Gulf of Mexico, which regularly has hurricanes and tropical storms during nesting season. We contrast the behavioral patterns and swimming energetics of these two turtles, the first tracked in calm weather and the second tracked before, during and after a tropical storm. Turtle 1 was highly active and swam at the surface or submerged 95% of the time during the entire inter-nesting period, with a high estimated specific oxygen consumption rate (0.95 ml min -1  kg -0.83 ). Turtle 2 was inactive for most of the first 9 days of the inter-nesting period, during which she rested at the bottom (80% of the time) with low estimated oxygen consumption (0.62 ml min -1  kg -0.83 ). Midway through the inter-nesting period, turtle 2 encountered a tropical storm and became highly active (swimming 88% of the time during and 95% after the storm). Her oxygen consumption increased significantly to 0.97 ml min -1  kg -0.83 during and 0.98 ml min -1  kg -0.83 after the storm. However, despite the tropical storm, turtle 2 returned to the nesting beach, where she successfully re-nested 75 m from her previous nest. Thus, the tropical storm had a minor effect on this female's individual nesting success, even though the storm caused 90% loss nests at Casey Key. © 2017. Published by The Company of Biologists Ltd.

Western Pond Turtle Head-starting and Reintroduction; 2003-2004 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Leuven, Susan; Allen, Harriet; Slavin, Kate

This report covers the results of the western pond turtle head-starting and reintroduction project for the period of October 2003-September 2004. Wild hatchling western pond turtles from the Columbia River Gorge were reared at the Woodland Park and Oregon Zoos in 2003 and 2004 as part of the recovery effort for this Washington State endangered species. The objective of the program is to reduce losses to introduced predators like bullfrogs and largemouth bass by raising the hatchlings to a size where they are too large to be eaten by most of these predators. Sixty-nine turtles were over-wintered at the Woodlandmore » Park Zoo and 69 at the Oregon Zoo. Of these, 136 head-started juvenile turtles were released at three sites in the Columbia Gorge in 2004. Two were held back to attain more growth in captivity. Thirty-four were released at the Klickitat ponds, 19 at the Klickitat lake, 21 at the Skamania site, and 62 at Pierce National Wildlife Refuge (NWR). This brought the total number of head-start turtles released since 1991 to 246 for the Klickitat ponds, 114 for the Klickitat lake, 167 for the Skamania pond complex, and 250 at Pierce NWR. In 2004, 32 females from the two Columbia Gorge populations were equipped with transmitters and monitored for nesting activity. Twenty-one of the females nested and produced 85 hatchlings. The hatchlings were collected in September and October and transported to the Woodland Park and Oregon zoos for rearing in the head-start program. Data collection for a four-year telemetry study of survival and habitat use by juvenile western pond turtles at Pierce NWR concluded in 2004. Radio transmitters on study animals were replaced as needed until all replacements were in service; afterward, the turtles were monitored until their transmitters failed. The corps of study turtles ranged from 39 in August 2003 to 2 turtles at the end of August 2004. These turtles showed the same seasonal pattern of movements between summer water and upland winter habitats observed in previous years. During the 2004 field season trapping effort, 345 western pond turtles were captured in the Columbia Gorge, including 297 previously head-started turtles. These recaptures, together with confirmed nesting by head-start females and visual resightings, indicate the program is succeeding in boosting juvenile recruitment to increase the populations. Records were also collected on 224 individual painted turtles captured in 2004 during trapping efforts at Pierce NWR, to gather baseline information on this native population. Bonneville Power Administration (BPA) funded approximately 60% of program activities in the Columbia River Gorge from October 2003 through September 2004.« less

Raccoon removal reduces sea turtle nest depredation in the Ten Thousand Islands of Florida

USGS Publications Warehouse

Garmestani, A.S.; Percival, H.F.

2005-01-01

Predation by raccoons, Procyon lotor marinus (L.), is the primary cause of sea turtle nest loss in the Ten Thousand Islands archipelago. Four islands within Ten Thousand Islands National Wildlife Refuge were surveyed for sea turtle nesting activity from 1991-95. Raccoons depredated 76-100% of nests on Panther Key from 1991-94, until 14 raccoons were removed in 1995 resulting in 0% depredation and 2 more were removed in 1996 resulting in 0% depredation. Raccoon removal may be an effective management option for increasing sea turtle nest survival on barrier islands.

Temperature Effects on Development and Phenotype in a Free-Living Population of Western Pond Turtles (Emys marmorata).

PubMed

Christie, Nicole E; Geist, Nicholas R

Changes in temperature regimes are occurring globally due to climate change as well as habitat alterations. Temperatures are expected to continue to rise in the future, along with a greater degree of climatic instability. Such changes could have potentially serious consequences for oviparous ectotherms, especially those with temperature-dependent sex determination. To investigate the effects of temperature on a range of developmental phenomena in a population of western pond turtles (Emys marmorata), we placed temperature sensors on top of each layer of eggs within nests and recorded temperatures hourly through the first 2-3 mo of incubation. These methods allowed us to look at in situ nest temperatures with high resolution. We found that mean incubation temperatures were similar between different nests and at different levels within nests but that incubation temperature fluctuations and maximum incubation temperatures differed greatly in both cases. The hatchling turtles were more likely to be female if they spent 30% or more of their sex-determining period of incubation above 29°C. Hatching success was best predicted by the maximum incubation temperature. We also found that incubation duration tended to be shorter as the mean temperature increased. However, exposure to either extremely high or low temperatures extended incubation times.

Cost-effectiveness of alternative conservation strategies with application to the Pacific leatherback turtle.

PubMed

Gjertsen, Heidi; Squires, Dale; Dutton, Peter H; Eguchi, Tomoharu

2014-02-01

Although holistic conservation addressing all sources of mortality for endangered species or stocks is the preferred conservation strategy, limited budgets require a criterion to prioritize conservation investments. We compared the cost-effectiveness of nesting site and at-sea conservation strategies for Pacific leatherback turtles (Dermochelys coriacea). We sought to determine which conservation strategy or mix of strategies would produce the largest increase in population growth rate per dollar. Alternative strategies included protection of nesters and their eggs at nesting beaches in Indonesia, gear changes, effort restrictions, and caps on turtle takes in the Hawaiian (U.S.A.) longline swordfish fishery, and temporal and area closures in the California (U.S.A.) drift gill net fishery. We used a population model with a biological metric to measure the effects of conservation alternatives. We normalized all effects by cost to prioritize those strategies with the greatest biological effect relative to its economic cost. We used Monte Carlo simulation to address uncertainty in the main variables and to calculate probability distributions for cost-effectiveness measures. Nesting beach protection was the most cost-effective means of achieving increases in leatherback populations. This result creates the possibility of noncompensatory bycatch mitigation, where high-bycatch fisheries invest in protecting nesting beaches. An example of this practice is U.S. processors of longline tuna and California drift gill net fishers that tax themselves to finance low-cost nesting site protection. Under certain conditions, fisheries interventions, such as technologies that reduce leatherback bycatch without substantially decreasing target species catch, can be cost-effective. Reducing bycatch in coastal areas where bycatch is high, particularly adjacent to nesting beaches, may be cost-effective, particularly, if fisheries in the area are small and of little commercial value. © 2014 Society for Conservation Biology.

High and variable mortality of leatherback turtles reveal possible anthropogenic impacts.

PubMed

Santidrián Tomillo, P; Robinson, N J; Sanz-Aguilar, A; Spotila, J R; Paladino, F V; Tavecchia, G

2017-08-01

The number of nesting leatherback turtles (Dermochelys coriacea) in the eastern Pacific Ocean has declined dramatically since the late 1980s. This decline has been attributed to egg poaching and interactions with fisheries. However, it is not clear how much of the decline should also be ascribed to variability in the physical characteristics of the ocean. We used data on individually marked turtles that nest at Playa Grande, Costa Rica, to address whether climatic variability affects survival and inter-breeding interval. Because some turtles might nest undetected, we used capture-recapture models to model survival probability accounting for a detection failure. In addition, as the probability of reproduction is constrained by past nesting events, we formulated a new parameterization to estimate inter-breeding intervals and contrast hypotheses on the role of climatic covariates on reproductive frequency. Average annual survival for the period 1993-2011 was low (0.78) and varied over time ranging from 0.49 to 0.99 with a negative temporal trend mainly due to the high mortality values registered after 2004. Survival probability was not associated with the Multivariate ENSO Index of the South Pacific Ocean (MEI) but this index explained 24% of the temporal variability in the reproductive frequency. The probability of a turtle to permanently leave after the first encounter was 26%. This high proportion of transients might be associated with a high mortality cost of the first reproduction or with a long-distance nesting dispersal after the first nesting season. Although current data do not allow separating these two hypotheses, low encounter rate at other locations and high investment in reproduction, supports the first hypothesis. The low and variable annual survival probability has largely contributed to the decline of this leatherback population. The lack of correlation between survival probability and the most important climatic driver of oceanic processes in the Pacific discards a climate-related decline and point to anthropogenic sources of mortality as the main causes responsible for the observed population decline. © 2017 by the Ecological Society of America.

LOGGERHEAD SEA TURTLE LATE NESTING ECOLOGY IN VIRGINIA BEACH, VIRGINIA

EPA Science Inventory

T'he.loggerhead sea turtle (Caretta came is the only recurrent nesting species of sea turtle in southeastern Virginia (Lutcavage & Musick, 1985; Dodd, 1988). Inasmuch as the loggerhead is a federally threatened species, the opportunity to gather data on its nesting ecology is imp...

Detection of Salmonella enterica Serovar Montevideo and Newport in Free-ranging Sea Turtles and Beach Sand in the Caribbean and Persistence in Sand and Seawater Microcosms.

PubMed

Ives, A-K; Antaki, E; Stewart, K; Francis, S; Jay-Russell, M T; Sithole, F; Kearney, M T; Griffin, M J; Soto, E

2017-09-01

Salmonellae are Gram-negative zoonotic bacteria that are frequently part of the normal reptilian gastrointestinal flora. The main objective of this project was to estimate the prevalence of non-typhoidal Salmonella enterica in the nesting and foraging populations of sea turtles on St. Kitts and in sand from known nesting beaches. Results suggest a higher prevalence of Salmonella in nesting leatherback sea turtles compared with foraging green and hawksbill sea turtles. Salmonella was cultured from 2/9 and identified by molecular diagnostic methods in 3/9 leatherback sea turtle samples. Salmonella DNA was detected in one hawksbill turtle, but viable isolates were not recovered from any hawksbill sea turtles. No Salmonella was detected in green sea turtles. In samples collected from nesting beaches, Salmonella was only recovered from a single dry sand sample. All recovered isolates were positive for the wzx gene, consistent with the O:7 serogroup. Further serotyping characterized serovars Montevideo and Newport present in cloacal and sand samples. Repetitive-element palindromic PCR (rep-PCR) fingerprint analysis and pulsed-field gel electrophoresis of the 2014 isolates from turtles and sand as well as archived Salmonella isolates recovered from leatherback sea turtles in 2012 and 2013, identified two distinct genotypes and four different pulsotypes, respectively. The genotyping and serotyping were directly correlated. To determine the persistence of representative strains of each serotype/genotype in these environments, laboratory-controlled microcosm studies were performed in water and sand (dry and wet) incubated at 25 or 35°C. Isolates persisted for at least 32 days in most microcosms, although there were significant decreases in culturable bacteria in several microcosms, with the greatest reduction in dry sand incubated at 35°C. This information provides a better understanding of the epizootiology of Salmonella in free-ranging marine reptiles and the potential public health risks associated with human interactions with these animals in the Caribbean. © 2016 Blackwell Verlag GmbH.

Soil hydric characteristics and environmental ice nuclei influence supercooling capacity of hatchling painted turtles Chrysemys picta.

PubMed

Costanzo, J P; Litzgus, J D; Iverson, J B; Lee, R E

1998-11-01

Hatchling painted turtles (Chrysemys picta) hibernate in their shallow natal nests where temperatures occasionally fall below -10 C during cold winters. Because the thermal limit of freeze tolerance in this species is approximately -4 C, hatchlings rely on supercooling to survive exposure to extreme cold. We investigated the influence of environmental ice nuclei on susceptibility to inoculative freezing in hatchling C. picta indigenous to the Sandhills of west-central Nebraska. In the absence of external ice nuclei, hatchlings cooled to -14.6 1.9 C (mean s.e.m.; N=5) before spontaneously freezing. Supercooling capacity varied markedly among turtles cooled in physical contact with sandy soil collected from nesting locales or samples of the native soil to which water-binding agents (clay or peat) had been added, despite the fact that all substrata contained the same amount of moisture (7.5 % moisture, w/w). The temperature of crystallization (Tc) of turtles exposed to frozen native soil was -1.6 0.4 C (N=5), whereas turtles exposed to frozen soil/clay and soil/peat mixtures supercooled extensively (mean Tc values approximately -13 C). Hatchlings cooled in contact with drier (less than or equal to 4 % moisture) native soil also supercooled extensively. Thus, inoculative freezing is promoted by exposure to sandy soils containing abundant moisture and little clay or organic matter. Soil collected at turtle nesting locales in mid and late winter contained variable amounts of moisture (4-15 % w/w) and organic matter (1-3 % w/w). In addition to ice, the soil at turtle nesting locales may harbor inorganic and organic ice nuclei that may also seed the freezing of hatchlings. Bulk samples of native soil, which were autoclaved to destroy any organic nuclei, nucleated aqueous solutions at approximately -7 C (Tc range -6.1 to -8.2 C). Non-autoclaved samples contained water-extractable, presumably organic, ice nuclei (Tc range -4.4 to -5.3 C). Ice nuclei of both classes varied in potency among turtle nesting locales. Interaction with ice nuclei in the winter microenvironment determines whether hatchling C. picta remain supercooled or freeze and may ultimately account for differential mortality in nests at a given locale and for variation in winter survival rates among populations.

A comparison of the seasonal movements of tiger sharks and green turtles provides insight into their predator-prey relationship.

PubMed

Fitzpatrick, Richard; Thums, Michele; Bell, Ian; Meekan, Mark G; Stevens, John D; Barnett, Adam

2012-01-01

During the reproductive season, sea turtles use a restricted area in the vicinity of their nesting beaches, making them vulnerable to predation. At Raine Island (Australia), the highest density green turtle Chelonia mydas rookery in the world, tiger sharks Galeocerdo cuvier have been observed to feed on green turtles, and it has been suggested that they may specialise on such air-breathing prey. However there is little information with which to examine this hypothesis. We compared the spatial and temporal components of movement behaviour of these two potentially interacting species in order to provide insight into the predator-prey relationship. Specifically, we tested the hypothesis that tiger shark movements are more concentrated at Raine Island during the green turtle nesting season than outside the turtle nesting season when turtles are not concentrated at Raine Island. Turtles showed area-restricted search behaviour around Raine Island for ∼3-4 months during the nesting period (November-February). This was followed by direct movement (transit) to putative foraging grounds mostly in the Torres Straight where they switched to area-restricted search mode again, and remained resident for the remainder of the deployment (53-304 days). In contrast, tiger sharks displayed high spatial and temporal variation in movement behaviour which was not closely linked to the movement behaviour of green turtles or recognised turtle foraging grounds. On average, tiger sharks were concentrated around Raine Island throughout the year. While information on diet is required to determine whether tiger sharks are turtle specialists our results support the hypothesis that they target this predictable and plentiful prey during turtle nesting season, but they might not focus on this less predictable food source outside the nesting season.

A Comparison of the Seasonal Movements of Tiger Sharks and Green Turtles Provides Insight into Their Predator-Prey Relationship

PubMed Central

Fitzpatrick, Richard; Thums, Michele; Bell, Ian; Meekan, Mark G.; Stevens, John D.; Barnett, Adam

2012-01-01

During the reproductive season, sea turtles use a restricted area in the vicinity of their nesting beaches, making them vulnerable to predation. At Raine Island (Australia), the highest density green turtle Chelonia mydas rookery in the world, tiger sharks Galeocerdo cuvier have been observed to feed on green turtles, and it has been suggested that they may specialise on such air-breathing prey. However there is little information with which to examine this hypothesis. We compared the spatial and temporal components of movement behaviour of these two potentially interacting species in order to provide insight into the predator-prey relationship. Specifically, we tested the hypothesis that tiger shark movements are more concentrated at Raine Island during the green turtle nesting season than outside the turtle nesting season when turtles are not concentrated at Raine Island. Turtles showed area-restricted search behaviour around Raine Island for ∼3–4 months during the nesting period (November–February). This was followed by direct movement (transit) to putative foraging grounds mostly in the Torres Straight where they switched to area-restricted search mode again, and remained resident for the remainder of the deployment (53–304 days). In contrast, tiger sharks displayed high spatial and temporal variation in movement behaviour which was not closely linked to the movement behaviour of green turtles or recognised turtle foraging grounds. On average, tiger sharks were concentrated around Raine Island throughout the year. While information on diet is required to determine whether tiger sharks are turtle specialists our results support the hypothesis that they target this predictable and plentiful prey during turtle nesting season, but they might not focus on this less predictable food source outside the nesting season. PMID:23284819

Atlantic Leatherback Migratory Paths and Temporary Residence Areas

PubMed Central

López-Mendilaharsu, Milagros; Miller, Philip; Domingo, Andrés; Evans, Daniel; Kelle, Laurent; Plot, Virginie; Prosdocimi, Laura; Verhage, Sebastian; Gaspar, Philippe; Georges, Jean-Yves

2010-01-01

Background Sea turtles are long-distance migrants with considerable behavioural plasticity in terms of migratory patterns, habitat use and foraging sites within and among populations. However, for the most widely migrating turtle, the leatherback turtle Dermochelys coriacea, studies combining data from individuals of different populations are uncommon. Such studies are however critical to better understand intra- and inter-population variability and take it into account in the implementation of conservation strategies of this critically endangered species. Here, we investigated the movements and diving behaviour of 16 Atlantic leatherback turtles from three different nesting sites and one foraging site during their post-breeding migration to assess the potential determinants of intra- and inter-population variability in migratory patterns. Methodology/Principal Findings Using satellite-derived behavioural and oceanographic data, we show that turtles used Temporary Residence Areas (TRAs) distributed all around the Atlantic Ocean: 9 in the neritic domain and 13 in the oceanic domain. These TRAs did not share a common oceanographic determinant but on the contrary were associated with mesoscale surface oceanographic features of different types (i.e., altimetric features and/or surface chlorophyll a concentration). Conversely, turtles exhibited relatively similar horizontal and vertical behaviours when in TRAs (i.e., slow swimming velocity/sinuous path/shallow dives) suggesting foraging activity in these productive regions. Migratory paths and TRAs distribution showed interesting similarities with the trajectories of passive satellite-tracked drifters, suggesting that the general dispersion pattern of adults from the nesting sites may reflect the extent of passive dispersion initially experienced by hatchlings. Conclusions/Significance Intra- and inter-population behavioural variability may therefore be linked with initial hatchling drift scenarios and be highly influenced by environmental conditions. This high degree of behavioural plasticity in Atlantic leatherback turtles makes species-targeted conservation strategies challenging and stresses the need for a larger dataset (>100 individuals) for providing general recommendations in terms of conservation. PMID:21085472

The Biophysical Characteristics Of Hatching Habitat Of Lekang Turtle (Lepidhochelys olivacea) Eggs In Turtle Conservation And Education Center, Bali

NASA Astrophysics Data System (ADS)

Suryono; Ario, R.; Wibowo, E.; Handoyo, G.

2018-02-01

Lekang turtle (Lepidhochelys olivacea) is one of the fauna that is protected as an endangered population. This marine reptile was able to migrate in great distance along the Indian Ocean, the Pacific Ocean, and South East Asia. Its existence has long been threatened, either by nature or human activities that endangered the population directly or indirectly. The decreasing number of sea turtle population that nest in Bali area is one indication of the reducing number of Lekang turtle in Indonesia. If left unchecked, it will result in the loss of Lekang turtle. This study aims to determine the successful percentage of conservation techniques and Lekang turtle hatching eggs (olive ridley sea turtle) in TCEC, Bali. The method used in this research is the method of observation or direct observation done in the field. Data collection is done by direct observation in the field. The results showed that the turtle breeding site is located in an area that is less strategic because too far from the sea, so that the temperature and humidity cannot be stable. Water content is most an important factor in the growth of embryo and egg hatching. This will lead to the decrease of hatching percentage of turtle eggs.

Temporal changes in artificial light exposure of marine turtle nesting areas.

PubMed

Kamrowski, Ruth L; Limpus, Col; Jones, Rhondda; Anderson, Sharolyn; Hamann, Mark

2014-08-01

Artificial light at night poses a significant threat to multiple taxa across the globe. In coastal regions, artificial lighting close to marine turtle nesting beaches is disruptive to their breeding success. Prioritizing effective management of light pollution requires an understanding of how the light exposure of nesting areas changes over time in response to changing temporal and spatial distributions of coastal development. We analyzed multitemporal, satellite night-light data, in combination with linear mixed model analysis, to determine broadscale changes in artificial light exposure at Australian marine turtle nesting areas between 1993 and 2010. We found seven marine turtle management units (MU), from five species, have experienced significant increases in light exposure over time, with flatback turtles nesting in east Australia experiencing the fastest increases. The remaining 12 MUs showed no significant change in light exposure. Unchanging MUs included those previously identified as having high exposure to light pollution (located in western Australia and southern Queensland), indicating that turtles in these areas have been potentially exposed to high light levels since at least the early nineties. At a finer geographic scale (within-MU), nine MUs contained nesting areas with significant increases in light exposure. These nesting areas predominantly occurred close to heavily industrialized coastal areas, thus emphasizing the importance of rigorous light management in industry. Within all MUs, nesting areas existed where light levels were extremely low and/or had not significantly increased since 1993. With continued coastal development, nesting females may shift to these darker/unchanging 'buffer' areas in the future. This is valuable information that informs our understanding of the capacity and resilience of marine turtles faced with coastal development: an understanding that is essential for effective marine turtle conservation. © 2013 John Wiley & Sons Ltd.

Climate change and temperature-linked hatchling mortality at a globally important sea turtle nesting site.

PubMed

Laloë, Jacques-Olivier; Cozens, Jacquie; Renom, Berta; Taxonera, Albert; Hays, Graeme C

2017-11-01

The study of temperature-dependent sex determination (TSD) in vertebrates has attracted major scientific interest. Recently, concerns for species with TSD in a warming world have increased because imbalanced sex ratios could potentially threaten population viability. In contrast, relatively little attention has been given to the direct effects of increased temperatures on successful embryonic development. Using 6603 days of sand temperature data recorded across 6 years at a globally important loggerhead sea turtle rookery-the Cape Verde Islands-we show the effects of warming incubation temperatures on the survival of hatchlings in nests. Incorporating published data (n = 110 data points for three species across 12 sites globally), we show the generality of relationships between hatchling mortality and incubation temperature and hence the broad applicability of our findings to sea turtles in general. We use a mechanistic approach supplemented by empirical data to consider the linked effects of warming temperatures on hatchling output and on sex ratios for these species that exhibit TSD. Our results show that higher temperatures increase the natural growth rate of the population as more females are produced. As a result, we project that numbers of nests at this globally important site will increase by approximately 30% by the year 2100. However, as incubation temperatures near lethal levels, the natural growth rate of the population decreases and the long-term survival of this turtle population is threatened. Our results highlight concerns for species with TSD in a warming world and underline the need for research to extend from a focus on temperature-dependent sex determination to a focus on temperature-linked hatchling mortalities. © 2017 John Wiley & Sons Ltd.

Stress hormone levels in a freshwater turtle from sites differing in human activity.

PubMed

Polich, Rebecca L

2016-01-01

Glucocorticoids, such as corticosterone (CORT), commonly serve as a measure of stress levels in vertebrate populations. These hormones have been implicated in regulation of feeding behaviour, locomotor activity, body mass, lipid metabolism and other crucial behaviours and physiological processes. Thus, understanding how glucocorticoids fluctuate seasonally and in response to specific stressors can yield insight into organismal health and the overall health of populations. I compared circulating CORT concentrations between two similar populations of painted turtle, Chrysemys picta, which differed primarily in the level of exposure to human recreational activities. I measured basal CORT concentrations as well as the CORT stress response and did not find any substantive difference between the two populations. This similarity may indicate that painted turtles are not stressed by the presence of humans during the nesting season. The results of this study contribute to our understanding of CORT concentrations in freshwater reptiles, a group that is historically under-represented in studies of circulating hormone concentrations; specifically, studies that seek to use circulating concentrations of stress hormones, such as CORT, as a measure of the effect of human activities on wild populations. They also give insight into how these species as a whole may respond to human recreational activities during crucial life-history stages, such as the nesting season. Although there was no discernable difference between circulating CORT concentrations between the urban and rural populations studied, I did find a significant difference in circulating CORT concentrations between male and female C. picta. This important finding provides better understanding of the sex differences between male and female painted turtles and adds to our understanding of this species and other species of freshwater turtle.

A genetic test of the natal homing versus social facilitation models for green turtle migration.

PubMed

Meylan, A B; Bowen, B W; Avise, J C

1990-05-11

Female green turtles exhibit strong nest-site fidelity as adults, but whether the nesting beach is the natal site is not known. Under the natal homing hypothesis, females return to their natal beach to nest, whereas under the social facilitation model, virgin females follow experienced breeders to nesting beaches and after a "favorable" nesting experience, fix on that site for future nestings. Differences shown in mitochondrial DNA genotype frequency among green turtle colonies in the Caribbean Sea and Atlantic Ocean are consistent with natal homing expectations and indicate that social facilitation to nonnatal sites is rare.

Solomon Islands Largest Hawksbill Turtle Rookery Shows Signs of Recovery after 150 Years of Excessive Exploitation

PubMed Central

Hamilton, Richard J.; Bird, Tomas; Gereniu, Collin; Pita, John; Ramohia, Peter C.; Walter, Richard; Goerlich, Clara; Limpus, Colin

2015-01-01

The largest rookery for hawksbill turtles in the oceanic South Pacific is the Arnavon Islands, which are located in the Manning Strait between Isabel and Choiseul Province, Solomon Islands. The history of this rookery is one of overexploitation, conflict and violence. Throughout the 1800s Roviana headhunters from New Georgia repeatedly raided the Manning Strait to collect hawksbill shell which they traded with European whalers. By the 1970s the Arnavons hawksbill population was in severe decline and the national government intervened, declaring the Arnavons a sanctuary in 1976. But this government led initiative was short lived, with traditional owners burning down the government infrastructure and resuming intensive harvesting in 1982. In 1991 routine beach monitoring and turtle tagging commenced at the Arnavons along with extensive community consultations regarding the islands’ future, and in 1995 the Arnavon Community Marine Conservation Area (ACMCA) was established. Around the same time national legislation banning the sale of all turtle products was passed. This paper represents the first analysis of data from 4536 beach surveys and 845 individual turtle tagging histories obtained from the Arnavons between 1991-2012. Our results and the results of others, reveal that many of the hawksbill turtles that nest at the ACMCA forage in distant Australian waters, and that nesting on the Arnavons occurs throughout the year with peak nesting activity coinciding with the austral winter. Our results also provide the first known evidence of recovery for a western pacific hawksbill rookery, with the number of nests laid at the ACMCA and the remigration rates of turtles doubling since the establishment of the ACMCA in 1995. The Arnavons case study provides an example of how changes in policy, inclusive community-based management and long term commitment can turn the tide for one of the most charismatic and endangered species on our planet. PMID:25853880

Solomon Islands largest hawksbill turtle rookery shows signs of recovery after 150 years of excessive exploitation.

PubMed

Hamilton, Richard J; Bird, Tomas; Gereniu, Collin; Pita, John; Ramohia, Peter C; Walter, Richard; Goerlich, Clara; Limpus, Colin

2015-01-01

The largest rookery for hawksbill turtles in the oceanic South Pacific is the Arnavon Islands, which are located in the Manning Strait between Isabel and Choiseul Province, Solomon Islands. The history of this rookery is one of overexploitation, conflict and violence. Throughout the 1800s Roviana headhunters from New Georgia repeatedly raided the Manning Strait to collect hawksbill shell which they traded with European whalers. By the 1970s the Arnavons hawksbill population was in severe decline and the national government intervened, declaring the Arnavons a sanctuary in 1976. But this government led initiative was short lived, with traditional owners burning down the government infrastructure and resuming intensive harvesting in 1982. In 1991 routine beach monitoring and turtle tagging commenced at the Arnavons along with extensive community consultations regarding the islands' future, and in 1995 the Arnavon Community Marine Conservation Area (ACMCA) was established. Around the same time national legislation banning the sale of all turtle products was passed. This paper represents the first analysis of data from 4536 beach surveys and 845 individual turtle tagging histories obtained from the Arnavons between 1991-2012. Our results and the results of others, reveal that many of the hawksbill turtles that nest at the ACMCA forage in distant Australian waters, and that nesting on the Arnavons occurs throughout the year with peak nesting activity coinciding with the austral winter. Our results also provide the first known evidence of recovery for a western pacific hawksbill rookery, with the number of nests laid at the ACMCA and the remigration rates of turtles doubling since the establishment of the ACMCA in 1995. The Arnavons case study provides an example of how changes in policy, inclusive community-based management and long term commitment can turn the tide for one of the most charismatic and endangered species on our planet.

Habitat use of breeding green turtles Chelonia mydas tagged in Dry Tortugas National Park: Making use of local and regional MPAs

USGS Publications Warehouse

Hart, Kristen; Zawada, David G.; Fujisaki, Ikuko; Lidz, Barbara H.

2013-01-01

Use of existing marine protected areas (MPAs) by far-ranging marine turtles can be determined using satellite telemetry. Because of a lack of information on MPA use by marine turtles in the Gulf of Mexico, we used satellite transmitters in 2010 and 2011 to track movements of 11 adult female breeding green turtles (Chelonia mydas) tagged in Dry Tortugas National Park (DRTO), in the Gulf of Mexico, south Florida, USA. Throughout the study period, turtles emerged every 9–18 days to nest. During the intervals between nesting episodes (i.e., inter-nesting periods), the turtles consistently used a common core-area within the DRTO boundary, determined using individual 50% kernel-density estimates (KDEs). We mapped the area in DRTO where individual turtle 50% KDEs overlapped using the USGS Along-Track Reef-Imaging System, and determined the diversity and distribution of various benthic-cover types within the mapped area. We also tracked turtles post-nesting as they transited to foraging sites 5–282 km away from tagging beaches; these sites were located both within DRTO and in the surrounding area of the Florida Keys and Florida Keys National Marine Sanctuary (FKNMS), a regional MPA. Year-round residency of 9 out of 11 individuals (82%) both within DRTO and in the FKNMS represents novel non-migratory behavior, which offers an opportunity for conservation of this imperiled species at both local and regional scales. These data comprise the first satellite-tracking results on adult nesting green turtles at this remote study site. Additional tracking could reveal whether the distinct inter-nesting and foraging sites delineated here will be repeatedly used in the future by these and other breeding green turtles.

Mixed-stock analysis reveals the migrations of juvenile hawksbill turtles (Eretmochelys imbricata) in the Caribbean Sea.

PubMed

Bowen, B W; Grant, W S; Hillis-Starr, Z; Shaver, D J; Bjorndal, K A; Bolten, A B; Bass, A L

2007-01-01

Hawksbill turtles (Eretmochelys imbricata) migrate between nesting beaches and feeding habitats that are often associated with tropical reefs, but it is uncertain which nesting colonies supply which feeding habitats. To address this gap in hawksbill biology, we compile previously published and new mitochondrial DNA (mtDNA) haplotype data for 10 nesting colonies (N = 347) in the western Atlantic and compare these profiles to four feeding populations and four previously published feeding samples (N = 626). Nesting colonies differ significantly in mtDNA haplotype frequencies (Phi(ST) = 0.588, P < 0.001), corroborating earlier conclusions of nesting site fidelity and setting the stage for mixed-stock analysis. Feeding aggregations show lower but significant structure (Phi(ST) = 0.089, P < 0.001), indicating that foraging populations are not homogenous across the Caribbean Sea. Bayesian mixed-stock estimates of the origins of juveniles in foraging areas show a highly significant, but shallow, correlation with nesting population size (r = 0.378, P = 0.004), supporting the premise that larger rookeries contribute more juveniles to feeding areas. A significant correlation between the estimated contribution and geographical distance from nesting areas (r = -0.394, P = 0.003) demonstrates the influence of proximity on recruitment to feeding areas. The influence of oceanic currents is illustrated by pelagic stage juveniles stranded in Texas, which are assigned primarily (93%) to the upstream rookery in Yucatan. One juvenile had a haplotype previously identified only in the eastern Atlantic, invoking rare trans-oceanic migrations. The mixed-stock analysis demonstrates that harvests in feeding habitats will impact nesting colonies throughout the region, with the greatest detriment to nearby nesting populations.

Identification of distinct movement patterns in Pacific leatherback turtle populations influenced by ocean conditions.

PubMed

Bailey, Helen; Benson, Scott R; Shillinger, George L; Bograd, Steven J; Dutton, Peter H; Eckert, Scott A; Morreale, Stephen J; Paladino, Frank V; Eguchi, Tomoharu; Foley, David G; Block, Barbara A; Piedra, Rotney; Hitipeuw, Creusa; Tapilatu, Ricardo F; Spotila, James R

2012-04-01

Interactions with fisheries are believed to be a major cause of mortality for adult leatherback turtles (Dermochelys coriacea), which is of particular concern in the Pacific Ocean, where they have been rapidly declining. In order to identify where these interactions are occurring and how they may be reduced, it is essential first to understand the movements and behavior of leatherback turtles. There are two regional nesting populations in the East Pacific (EP) and West Pacific (WP), comprising multiple nesting sites. We synthesized tracking data from the two populations and compared their movement patterns. A switching state-space model was applied to 135 Argos satellite tracks to account for observation error, and to distinguish between migratory and area-restricted search behaviors. The tracking data, from the largest leatherback data set ever assembled, indicated that there was a high degree of spatial segregation between EP and WP leatherbacks. Area-restricted search behavior mainly occurred in the southeast Pacific for the EP leatherbacks, whereas the WP leatherbacks had several different search areas in the California Current, central North Pacific, South China Sea, off eastern Indonesia, and off southeastern Australia. We also extracted remotely sensed oceanographic data and applied a generalized linear mixed model to determine if leatherbacks exhibited different behavior in relation to environmental variables. For the WP population, the probability of area-restricted search behavior was positively correlated with chlorophyll-a concentration. This response was less strong in the EP population, but these turtles had a higher probability of search behavior where there was greater Ekman upwelling, which may increase the transport of nutrients and consequently prey availability. These divergent responses to oceanographic conditions have implications for leatherback vulnerability to fisheries interactions and to the effects of climate change. The occurrence of leatherback turtles within both coastal and pelagic areas means they have a high risk of exposure to many different fisheries, which may be very distant from their nesting sites. The EP leatherbacks have more limited foraging grounds than the WP leatherbacks, which could make them more susceptible to any temperature or prey changes that occur in response to climate change.

The role of geomagnetic cues in green turtle open sea navigation.

PubMed

Benhamou, Simon; Sudre, Joël; Bourjea, Jérome; Ciccione, Stéphane; De Santis, Angelo; Luschi, Paolo

2011-01-01

Laboratory and field experiments have provided evidence that sea turtles use geomagnetic cues to navigate in the open sea. For instance, green turtles (Chelonia mydas) displaced 100 km away from their nesting site were impaired in returning home when carrying a strong magnet glued on the head. However, the actual role of geomagnetic cues remains unclear, since magnetically treated green turtles can perform large scale (>2000 km) post-nesting migrations no differently from controls. In the present homing experiment, 24 green turtles were displaced 200 km away from their nesting site on an oceanic island, and tracked, for the first time in this type of experiment, with Global Positioning System (GPS), which is able to provide much more frequent and accurate locations than previously used tracking methods. Eight turtles were magnetically treated for 24-48 h on the nesting beach prior to displacement, and another eight turtles had a magnet glued on the head at the release site. The last eight turtles were used as controls. Detailed analyses of water masses-related (i.e., current-corrected) homing paths showed that magnetically treated turtles were able to navigate toward their nesting site as efficiently as controls, but those carrying magnets were significantly impaired once they arrived within 50 km of home. While green turtles do not seem to need geomagnetic cues to navigate far from the goal, these cues become necessary when turtles get closer to home. As the very last part of the homing trip (within a few kilometers of home) likely depends on non-magnetic cues, our results suggest that magnetic cues play a key role in sea turtle navigation at an intermediate scale by bridging the gap between large and small scale navigational processes, which both appear to depend on non-magnetic cues.

Endogenous and exogenous ice-nucleating agents constrain supercooling in the hatchling painted turtle.

PubMed

Costanzo, Jon P; Baker, Patrick J; Dinkelacker, Stephen A; Lee, Richard E

2003-02-01

Hatchlings of the painted turtle (Chrysemys picta) commonly hibernate in their shallow, natal nests. Survival at temperatures below the limit of freeze tolerance (approximately -4 degrees C) apparently depends on their ability to remain supercooled, and, whereas previous studies have reported that supercooling capacity improves markedly with cold acclimation, the mechanistic basis for this change is incompletely understood. We report that the crystallization temperature (T(c)) of recently hatched (summer) turtles acclimated to 22 degrees C and reared on a substratum of vermiculite or nesting soil was approximately 5 degrees C higher than the T(c) determined for turtles acclimated to 4 degrees C and tested in winter. This increase in supercooling capacity coincided with elimination of substratum (and, in fewer cases, eggshell) that the hatchlings had ingested; however, this association was not necessarily causal because turtles reared on a paper-covered substratum did not ingest exogenous matter but nevertheless showed a similar increase in supercooling capacity. Our results for turtles reared on paper revealed that seasonal development of supercooling capacity fundamentally requires elimination of ice-nucleating agents (INA) of endogenous origin: summer turtles, but not winter turtles, produced feces (perhaps derived from residual yolk) that expressed ice-nucleating activity. Ingestion of vermiculite or eggshell, which had modest ice-nucleating activity, had no effect on the T(c), whereas ingestion of nesting soil, which contained two classes of potent INA, markedly reduced the supercooling capacity of summer turtles. This effect persisted long after the turtles had purged their guts of soil particles, because the T(c) of winter turtles reared on nesting soil (mean +/- S.E.M.=-11.6+/-1.4 degrees C) was approximately 6 degrees C higher than the T(c) of winter turtles reared on vermiculite or paper. Experiments in which winter turtles were fed INA commonly found in nesting soil showed that water-soluble, organic agents can remain fully active for at least one month. Such INA may account for the limited supercooling capacity (T(c) approximately -7.5 degrees C) we found in turtles overwintering in natural nests and may therefore pose a formidable challenge to the winter survival of hatchling C. picta.

Engaging Students in Science: Turtle Nestwatch

ERIC Educational Resources Information Center

Lewis, Elaine; Baudains, Catherine; Mansfield, Caroline

2009-01-01

Involving students in authentic science work is one way to enhance their interest in science. This paper reports a project in which Year 4-7 students actively participated in a study that involved the provision of a suitable nesting site for local turtles. The students collected data on turtle nests at the site and evidence of turtle hatchlings at…

Forecasting range expansion into ecological traps: climate-mediated shifts in sea turtle nesting beaches and human development.

PubMed

Pike, David A

2013-10-01

Some species are adapting to changing environments by expanding their geographic ranges. Understanding whether range shifts will be accompanied by increased exposure to other threats is crucial to predicting when and where new populations could successfully establish. If species overlap to a greater extent with human development under climate change, this could form ecological traps which are attractive to dispersing individuals, but the use of which substantially reduces fitness. Until recently, the core nesting range for the Critically Endangered Kemp's ridley sea turtle (Lepidochelys kempii) was ca. 1000 km of sparsely populated coastline in Tamaulipas, Mexico. Over the past twenty-five years, this species has expanded its range into populated areas of coastal Florida (>1500 km outside the historical range), where nesting now occurs annually. Suitable Kemp's ridley nesting habitat has persisted for at least 140 000 years in the western Gulf of Mexico, and climate change models predict further nesting range expansion into the eastern Gulf of Mexico and northern Atlantic Ocean. Range expansion is 6-12% more likely to occur along uninhabited stretches of coastline than are current nesting beaches, suggesting that novel nesting areas will not be associated with high levels of anthropogenic disturbance. Although the high breeding-site fidelity of some migratory species could limit adaptation to climate change, rapid population recovery following effective conservation measures may enhance opportunities for range expansion. Anticipating the interactive effects of past or contemporary conservation measures, climate change, and future human activities will help focus long-term conservation strategies. © 2013 John Wiley & Sons Ltd.

Distribution and Feeding Behavior of Omorgus suberosus (Coleoptera: Trogidae) in Lepidochelys olivacea Turtle Nests

PubMed Central

Baena, Martha L.; Escobar, Federico; Halffter, Gonzalo; García–Chávez, Juan H.

2015-01-01

Omorgus suberosus (Fabricius, 1775) has been identified as a potential predator of the eggs of the turtle Lepidochelys olivacea (Eschscholtz, 1829) on one of the main turtle nesting beaches in the world, La Escobilla in Oaxaca, Mexico. This study presents an analysis of the spatio–temporal distribution of the beetle on this beach (in areas of high and low density of L. olivacea nests over two arrival seasons) and an evaluation, under laboratory conditions, of the probability of damage to the turtle eggs by this beetle. O. suberosus adults and larvae exhibited an aggregated pattern at both turtle nest densities; however, aggregation was greater in areas of low nest density, where we found the highest proportion of damaged eggs. Also, there were fluctuations in the temporal distribution of the adult beetles following the arrival of the turtles on the beach. Under laboratory conditions, the beetles quickly damaged both dead eggs and a mixture of live and dead eggs, but were found to consume live eggs more slowly. This suggests that O. suberosus may be recycling organic material; however, its consumption of live eggs may be sufficient in some cases to interrupt the incubation period of the turtle. We intend to apply these results when making decisions regarding the L. olivacea nests on La Escobilla Beach, one of the most important sites for the conservation of this species. PMID:26422148

Asynchronous emergence by loggerhead turtle (Caretta caretta) hatchlings

NASA Astrophysics Data System (ADS)

Houghton, J. D. R.; Hays, G. C.

2001-03-01

For many decades it has been accepted that marine turtle hatchlings from the same nest generally emerge from the sand together. However, for loggerhead turtles (Caretta caretta) nesting on the Greek Island of Kefalonia, a more asynchronous pattern of emergence has been documented. By placing temperature loggers at the top and bottom of nests laid on Kefalonia during 1998, we examined whether this asynchronous emergence was related to the thermal conditions within nests. Pronounced thermal variation existed not only between, but also within, individual nests. These within-nest temperature differences were related to the patterns of hatchling emergence, with hatchlings from nests displaying large thermal ranges emerging over a longer time-scale than those characterised by more uniform temperatures.

Head-started Kemp’s ridley turtle (Lepidochelys kempii) nest recorded in Florida: Possible implications

USGS Publications Warehouse

Shaver, Donna J.; Lamont, Margaret M.; Maxwell, Sharon; Walker, Jennifer Shelby; Dillingham, Ted

2016-01-01

A head-started Kemp’s ridley sea turtle (Lepidochelys kempii) was documented nesting on South Walton Beach, Florida on 25 May 2015. This record supports the possibility that exposure to Florida waters after being held in captivity through 1–3 yrs of age during the head-starting process may have influenced future nest site selection of this and perhaps other Kemp’s ridley turtles. Such findings could have important ramifications for marine water experimentation and release site selection for turtles that have been reared in captivity.

Sporadic nesting reveals long distance colonisation in the philopatric loggerhead sea turtle (Caretta caretta).

PubMed

Carreras, Carlos; Pascual, Marta; Tomás, Jesús; Marco, Adolfo; Hochscheid, Sandra; Castillo, Juan José; Gozalbes, Patricia; Parga, Mariluz; Piovano, Susanna; Cardona, Luis

2018-01-23

The colonisation of new suitable habitats is crucial for species survival at evolutionary scale under changing environmental conditions. However, colonisation potential may be limited by philopatry that facilitates exploiting successful habitats across generations. We examine the mechanisms of long distance dispersal of the philopatric loggerhead sea turtle (Caretta caretta) by analysing 40 sporadic nesting events in the western Mediterranean. The analysis of a fragment of the mitochondrial DNA and 7 microsatellites of 121 samples from 18 of these nesting events revealed that these nests were colonising events associated with juveniles from distant populations feeding in nearby foraging grounds. Considering the temperature-dependent sex determination of the species, we simulated the effect of the incubation temperature and propagule pressure on a potential colonisation scenario. Our results indicated that colonisation will succeed if warm temperature conditions, already existing in some of the beaches in the area, extend to the whole western Mediterranean. We hypothesize that the sporadic nesting events in developmental foraging grounds may be a mechanism to overcome philopatry limitations thus increasing the dispersal capabilities of the species and the adaptability to changing environments. Sporadic nesting in the western Mediterranean can be viewed as potential new populations in a scenario of rising temperatures.

Asynchronous emergence by loggerhead turtle (Caretta caretta) hatchlings.

PubMed

Houghton, J D; Hays, G C

2001-03-01

For many decades it has been accepted that marine turtle hatchlings from the same nest generally emerge from the sand together. However, for loggerhead turtles (Caretta caretta) nesting on the Greek Island of Kefalonia, a more asynchronous pattern of emergence has been documented. By placing temperature loggers at the top and bottom of nests laid on Kefalonia during 1998, we examined whether this asynchronous emergence was related to the thermal conditions within nests. Pronounced thermal variation existed not only between, but also within, individual nests. These within-nest temperature differences were related to the patterns of hatchling emergence, with hatchlings from nests displaying large thermal ranges emerging over a longer time-scale than those characterised by more uniform temperatures. In many egg-laying animals, parental care of the offspring may continue while the eggs are incubating and also after they have hatched. Consequently, the importance of the nest site for determining incubation conditions may be reduced since the parents themselves may alter the local environment. By contrast, in marine turtles, parental care ceases once the eggs have been laid and the nest site covered. The positioning of the nest site, in both space and time, may therefore have profound effects for marine turtles by affecting, for example, the survival of the eggs and hatchlings as well as their sex (Janzen and Paukstis 1991). During incubation, sea turtle embryos grow from a few cells at oviposition to a self-sufficient organism at hatching some 50-80 days later (Ackerman 1997). After hatching, the young turtles dig up through the sand and emerge typically en masse at the surface 1-7 nights later, with a number of stragglers following over the next few nights (Christens 1990). This contrasts with the frequently observed pattern of hatching asynchrony in birds. It has been suggested that the cause of mass emergence in turtles is that eggs within a clutch are fertilised within a short period of time and then, when thermal conditions within the nest are uniform, develop at very similar rates and hence hatch and emerge together (Porter 1972). As a corollary of this idea, it would be predicted that when there are pronounced within-nest thermal gradients, development rates of siblings will be different and hence asynchronous hatching and emergence might occur. While it may be energetically beneficial for hatchlings to emerge in a group (Carr and Hirth 1961), if the extent of hatching asynchrony is marked then there may be severe costs for individuals if they wait for all their siblings to hatch before attempting to dig out of the sand (Hays and Speakman 1992). Under such conditions, the protracted emergence of small groups of hatchlings over several nights may be favoured. Examination of the literature suggests that emergence asynchrony may be more widespread than generally considered. For example, Witherington et al. (1990) described loggerhead turtle hatchlings (Caretta caretta) emerging over 4 days in Florida; for green turtles (Chelonia mydas), Hendrickson (1958) documented that nests in Malaysia and Sarawak produced hatchlings for up to 8 days; whilst Diamond (1976) found that hawksbill (Eretmochelys imbricata) nests on Cousin Island, Seychelles, were active for up to 4 days. Similarly, on the Greek Island of Kefalonia, we have shown that emergence from individual loggerhead turtle nests may occur on up to 11 nights (Hays and Speakman 1992). It is logical to suppose that asynchronous emergence relates to thermal gradients within nests, since the incubation duration of sea turtle eggs is related to temperature, with eggs hatching quicker when the temperature is higher. Here we test this hypothesis by measuring thermal variations within loggerhead turtle nests and comparing these variations to the patterns of hatchling emergence.

Hawksbill turtle terra incognita: conservation genetics of eastern Pacific rookeries.

PubMed

Gaos, Alexander R; Lewison, Rebecca L; Liles, Michael J; Gadea, Velkiss; Altamirano, Eduardo; Henríquez, Ana V; Torres, Perla; Urteaga, José; Vallejo, Felipe; Baquero, Andres; LeMarie, Carolina; Muñoz, Juan Pablo; Chaves, Jaime A; Hart, Catherine E; Peña de Niz, Alejandro; Chácon, Didiher; Fonseca, Luis; Otterstrom, Sarah; Yañez, Ingrid L; LaCasella, Erin L; Frey, Amy; Jensen, Michael P; Dutton, Peter H

2016-02-01

Prior to 2008 and the discovery of several important hawksbill turtle (Eretmochelys imbricata) nesting colonies in the EP (Eastern Pacific), the species was considered virtually absent from the region. Research since that time has yielded new insights into EP hawksbills, salient among them being the use of mangrove estuaries for nesting. These recent revelations have raised interest in the genetic characterization of hawksbills in the EP, studies of which have remained lacking to date. Between 2008 and 2014, we collected tissue samples from 269 nesting hawksbills at nine rookeries across the EP and used mitochondrial DNA sequences (766 bp) to generate the first genetic characterization of rookeries in the region. Our results inform genetic diversity, population differentiation, and phylogeography of the species. Hawksbills in the EP demonstrate low genetic diversity: We identified a total of only seven haplotypes across the region, including five new and two previously identified nesting haplotypes (pooled frequencies of 58.4% and 41.6%, respectively), the former only evident in Central American rookeries. Despite low genetic diversity, we found strong stock structure between the four principal rookeries, suggesting the existence of multiple populations and warranting their recognition as distinct management units. Furthermore, haplotypes EiIP106 and EiIP108 are unique to hawksbills that nest in mangrove estuaries, a behavior found only in hawksbills along Pacific Central America. The detected genetic differentiation supports the existence of a novel mangrove estuary "reproductive ecotype" that may warrant additional conservation attention. From a phylogeographic perspective, our research indicates hawksbills colonized the EP via the Indo-Pacific, and do not represent relict populations isolated from the Atlantic by the rising of the Panama Isthmus. Low overall genetic diversity in the EP is likely the combined result of few rookeries, extremely small reproductive populations and evolutionarily recent colonization events. Additional research with larger sample sizes and variable markers will help further genetic understanding of hawksbill turtles in the EP.

Association between nighttime artificial light pollution and sea turtle nest density along Florida coast: A geospatial study using VIIRS remote sensing data.

PubMed

Hu, Zhiyong; Hu, Hongda; Huang, Yuxia

2018-08-01

Artificial lighting at night has becoming a new type of pollution posing an important anthropogenic environmental pressure on organisms. The objective of this research was to examine the potential association between nighttime artificial light pollution and nest densities of the three main sea turtle species along Florida beaches, including green turtles, loggerheads, and leatherbacks. Sea turtle survey data was obtained from the "Florida Statewide Nesting Beach Survey program". We used the new generation of satellite sensor "Visible Infrared Imaging Radiometer Suite (VIIRS)" (version 1 D/N Band) nighttime annual average radiance composite image data. We defined light pollution as artificial light brightness greater than 10% of the natural sky brightness above 45° of elevation (>1.14 × 10 -11 Wm -2 sr -1 ). We fitted a generalized linear model (GLM), a GLM with eigenvectors spatial filtering (GLM-ESF), and a generalized estimating equations (GEE) approach for each species to examine the potential correlation of nest density with light pollution. Our models are robust and reliable in terms of the ability to deal with data distribution and spatial autocorrelation (SA) issues violating model assumptions. All three models found that nest density is significantly negatively correlated with light pollution for each sea turtle species: the higher light pollution, the lower nest density. The two spatially extended models (GLM-ESF and GEE) show that light pollution influences nest density in a descending order from green turtles, to loggerheads, and then to leatherbacks. The research findings have an implication for sea turtle conservation policy and ordinance making. Near-coastal lights-out ordinances and other approaches to shield lights can protect sea turtles and their nests. The VIIRS DNB light data, having significant improvements over comparable data by its predecessor, the DMSP-OLS, shows promise for continued and improved research about ecological effects of artificial light pollution. Copyright © 2018 Elsevier Ltd. All rights reserved.

Baseline plasma corticosterone, haematological and biochemical results in nesting and rehabilitating loggerhead sea turtles (Caretta caretta).

PubMed

Flower, Jennifer E; Norton, Terry M; Andrews, Kimberly M; Nelson, Steven E; Parker, Clare E; Romero, L Michael; Mitchell, Mark A

2015-01-01

The evaluation of hormonal responses to stress in reptiles relies on acquisition of baseline corticosterone concentrations; however, the stress associated with the restraint needed to collect the blood samples can affect the results. The purpose of this study was to determine a time limit for the collection of blood samples to evaluate baseline corticosterone, haematological and biochemical results in nesting (n = 11) and rehabilitating (n = 16) loggerhead sea turtles (Caretta caretta). Blood samples were collected from the dorsal cervical sinus of each turtle immediately after touching the animal (t 0; 0-3 min) and 3 (t 3; 3-6 min), 6 (t 6; 6-9 min; nesting turtles only), 10 (t 10; 10-13 min) and 30 min (t 30; rehabilitating turtles only) after the initial hands-on time. Consistent between the rehabilitating and nesting turtles, there was a subtle yet significant increase in white blood cell counts over time. Despite the fact that white blood cell counts increased during the sampling period, there was no direct correlation between white blood cell count and corticosterone in the sampled turtles. In the nesting turtles, significant elevations in corticosterone were noted between t 0 and t 3 (P = 0.014) and between t 0 and t 6 (P = 0.022). Values at t 10 were not significantly different from those at t 0 (P = 0.102); however, there was a trend for the corticosterone values to continue to increase. These results suggest that sampling of nesting loggerhead sea turtles within 3 min of handling will provide baseline corticosterone concentrations in their natural environment. Significant elevations in corticosterone were also noted in the rehabilitating loggerhead sea turtles between t 0 and t 10 (P = 0.02) and between t 0 and t 30 of sampling (P = 0.0001). These results suggest that sampling of loggerhead sea turtles within 6 min of handling should provide baseline corticosterone concentrations in a rehabilitation setting. The delay in the corticosterone response noted in the rehabilitating turtles may be associated with the daily contact (visual or direct) they have with their human caretakers.

Warm water and cool nests are best. How global warming might influence hatchling green turtle swimming performance.

PubMed

Booth, David T; Evans, Andrew

2011-01-01

For sea turtles nesting on beaches surrounded by coral reefs, the most important element of hatchling recruitment is escaping predation by fish as they swim across the fringing reef, and as a consequence hatchlings that minimize their exposure to fish predation by minimizing the time spent crossing the fringing reef have a greater chance of surviving the reef crossing. One way to decrease the time required to cross the fringing reef is to maximize swimming speed. We found that both water temperature and nest temperature influence swimming performance of hatchling green turtles, but in opposite directions. Warm water increases swimming ability, with hatchling turtles swimming in warm water having a faster stroke rate, while an increase in nest temperature decreases swimming ability with hatchlings from warm nests producing less thrust per stroke.

Breeding loggerhead marine turtles Caretta caretta in Dry Tortugas National Park, USA, show high fidelity to diverse habitats near nesting beaches

USGS Publications Warehouse

Hart, Kristen M.; Zawada, David G.; Sartain-Iverson, Autumn R.; Fujisaki, Ikuko

2016-01-01

We used satellite telemetry to identify in-water habitat used by individuals in the smallest North-west Atlantic subpopulation of adult nesting loggerhead turtles Caretta caretta during the breeding season. During 2010, 2011 and 2012 breeding periods, a total of 20 adult females used habitats proximal to nesting beaches with various levels of protection within Dry Tortugas National Park. We then used a rapid, high-resolution, digital imaging system to map habitat adjacent to nesting beaches, revealing the diversity and distribution of available benthic cover. Turtle behaviour showing measurable site-fidelity to these diverse habitats has implications for managing protected areas and human activities within them. Protecting diverse benthic areas adjacent to loggerhead turtle nesting beaches here and elsewhere could provide benefits for overall biodiversity conservation.

Nesting ecology of Chelonia mydas (Testudines: Cheloniidae) on the Guanahacabibes Peninsula, Cuba.

PubMed

Azanza Ricardo, Julia; Ibarra Martín, Maria E; González Sansón, Gaspar; Abreu Grobois, F Alberto; Eckert, Karen L; Espinosa López, Georgina; Oyama, Ken

2013-12-01

The nesting colony of green sea turtles (Chelonia mydas) at Guanahacabibes Peninsula Biosphere Reserve and National Park is one of the largest in the Cuban archipelago; however, little information about its nesting ecology is available. Temporal and spatial variation in nesting and reproductive success as well as morphometric characteristics of gravid females were used to ecologically characterize this colony. Nine beaches of the Southernmost coast of Guanahacabibes Peninsula were monitored for 14 years (1998-2012) to determine green turtle nesting activity, from May to September (peak nesting season in this area). Beach dimensions were measured to determine nest density using the length and the area. Afterward the beaches were divided in two categories, index and secondary. Females were measured and tagged to compare new tagged females (823) with returning tagged females (140). Remigration interval was also determined. Temporal variation was identified as the annual number of nesting emergences and oviposits per female, with apparent peaks in reproductive activity on a biennial cycle in the first six years followed by periods of annual increase in nest number (2003-2008) and periods of decreasing number of nests (2010-2012). We also found intra-seasonal variation with the highest nesting activity in July, particularly in the second half of the month. The peak emergence time was 22:00-02:00 hr. In terms of spatial variation, smaller beaches had the highest nest density and nesting was more frequent 6-9m from the high tide line, where hatchling production was maximized although hatchling success was high on average, above 80%. Morphometric analysis of females was made and newly tagged turtles were smaller on average than remigrants. Our results are only a first attempt at characterizing Guanahacabibes' populations but have great value for establishing conservation priorities within the context of national management plans, and for efficient monitoring and protection of nesting beaches.

The Role of Geomagnetic Cues in Green Turtle Open Sea Navigation

PubMed Central

Benhamou, Simon; Sudre, Joël; Bourjea, Jérome; Ciccione, Stéphane; De Santis, Angelo; Luschi, Paolo

2011-01-01

Background Laboratory and field experiments have provided evidence that sea turtles use geomagnetic cues to navigate in the open sea. For instance, green turtles (Chelonia mydas) displaced 100 km away from their nesting site were impaired in returning home when carrying a strong magnet glued on the head. However, the actual role of geomagnetic cues remains unclear, since magnetically treated green turtles can perform large scale (>2000 km) post-nesting migrations no differently from controls. Methodology/Principal Findings In the present homing experiment, 24 green turtles were displaced 200 km away from their nesting site on an oceanic island, and tracked, for the first time in this type of experiment, with Global Positioning System (GPS), which is able to provide much more frequent and accurate locations than previously used tracking methods. Eight turtles were magnetically treated for 24–48 h on the nesting beach prior to displacement, and another eight turtles had a magnet glued on the head at the release site. The last eight turtles were used as controls. Detailed analyses of water masses-related (i.e., current-corrected) homing paths showed that magnetically treated turtles were able to navigate toward their nesting site as efficiently as controls, but those carrying magnets were significantly impaired once they arrived within 50 km of home. Conclusions/Significance While green turtles do not seem to need geomagnetic cues to navigate far from the goal, these cues become necessary when turtles get closer to home. As the very last part of the homing trip (within a few kilometers of home) likely depends on non-magnetic cues, our results suggest that magnetic cues play a key role in sea turtle navigation at an intermediate scale by bridging the gap between large and small scale navigational processes, which both appear to depend on non-magnetic cues. PMID:22046329

A survey of the epibiota of Eretmochelys imbricata (Testudines: Cheloniidae) of Mona Island, Puerto Rico.

PubMed

Schärer, Michelle T

2003-06-01

Epibiotic organisms inhabiting non-nesting hawksbill sea turtles, Eretmochelys imbricata (Linnaeus, 1766), are described from Mona and Monito Islands, Puerto Rico. Epibiont samples from 105 turtles of shallow (< 40 m) water foraging habitats were collected and identified to the lowest possible taxon. This epibiotic assemblage consisting of at least 4 algal functional groups and 12 animal phyla represents the greatest phylogenetic diversity for marine turtle epibiota. Six groups are considered new reports for marine turtles. Most epibiont colonization was found on posterior marginal scutes and under overlapping scutes. Ecological attributes of epibiota and their symbiosis with E. imbricata provide a tool to understand basi and epibiont populations.

First satellite tracks of South Atlantic sea turtle ‘lost years’: seasonal variation in trans-equatorial movement

PubMed Central

Mendilaharsu, Milagros L.; dei Marcovaldi, Maria A. G.; Sacco, Alexander E.; Lopez, Gustave; Pires, Thais; Swimmer, Yonat

2017-01-01

In the South Atlantic Ocean, few data exist regarding the dispersal of young oceanic sea turtles. We characterized the movements of laboratory-reared yearling loggerhead turtles from Brazilian rookeries using novel telemetry techniques, testing for differences in dispersal during different periods of the sea turtle hatching season that correspond to seasonal changes in ocean currents. Oceanographic drifters deployed alongside satellite-tagged turtles allowed us to explore the mechanisms of dispersal (passive drift or active swimming). Early in the hatching season turtles transited south with strong southward currents. Late in the hatching season, when currents flowed in the opposite direction, turtles uniformly moved northwards across the Equator. However, the movement of individuals differed from what was predicted by surface currents alone. Swimming velocity inferred from track data and an ocean circulation model strongly suggest that turtles' swimming plays a role in maintaining their position within frontal zones seaward of the continental shelf. The long nesting season of adults and behaviour of post-hatchlings exposes young turtles to seasonally varying ocean conditions that lead some individuals further into the South Atlantic and others into the Northern Hemisphere. Such migratory route diversity may ultimately buffer the population against environmental changes or anthropologic threats, fostering population resiliency. PMID:29212722

Nest placement of the giant Amazon river turtle, Podocnemis expansa, in the Araguaia River, Goiás State, Brazil.

PubMed

Ferreira, Paulo Dias Júnior; Castro, Paulo de Tarso Amorim

2005-05-01

The giant Amazon river turtle (Podocnemis expansa) nests on extensive sand bars on the margins and interior of the channel during the dry season. The high concentration of nests in specific points of certain beaches indicates that the selection of nest placement is not random but is related to some geological aspects, such as bar margin inclination and presence of a high, sandy platform. The presence of access channels to high platform points or ramp morphology are decisive factors in the choice of nesting areas. The eroded and escarped margins of the beaches hinder the Amazon river turtle arriving at the most suitable places for nesting. Through the years, changes in beach morphology can alter nest distribution.

Collecting a sample of loggerhead sea turtle hatchlings before a natural emergence does not reduce nest productivity

USGS Publications Warehouse

Salmon, Michael; Carthy, Raymond R.; Lohmann, Catherine M. F.; Lohmann, Kenneth J.; Wyneken, Jeanette

2012-01-01

 In numerous studies involving hatchling sea turtles, researchers have collected small numbers of hatchlings from nests a few hours before the turtles would otherwise have emerged naturally. This procedure makes it possible to do experiments in which the behavioral or physiological responses of numerous hatchlings must be tested in a limited period of time, and also allows hatchlings to be released back into the sea in time to migrate offshore before dawn. In principle, however, the procedure might inadvertently reduce nest productivity (the number of hatchlings that successfully leave the nest), if digging into a nest prior to emergence somehow reduces the ability of the remaining turtles to emerge. We compared nest productivity in 67 experimental loggerhead nests, from which we removed 10 hatchlings before a natural emergence, to 95 control nests left undisturbed before a natural emergence. The 2 groups showed no statistical differences in productivity. We conclude that taking a few hatchlings from a loggerhead nest shortly before a natural emergence has no negative impact on hatchling production if sampling is done with care at locations where there are few nest predators, and at sites where an emergence can be predicted because nest deposition dates are known.

An odyssey of the green sea turtle: Ascension Island revisited

PubMed Central

Bowen, Brian W.; Meylan, Anne B.; Avise, John C.

1989-01-01

Green turtles (Chelonia mydas) that nest on Ascension Island, in the south-central Atlantic, utilize feeding grounds along the coast of Brazil, more than 2000 km away. To account for the origins of this remarkable migratory behavior, Carr and Coleman [Carr, A. & Coleman, P. J. (1974) Nature (London) 249, 128-130] proposed a vicariant biogeographic scenario involving plate tectonics and natal homing. Under the Carr-Coleman hypothesis, the ancestors of Ascension Island green turtles nested on islands adjacent to South America in the late Cretaceous, soon after the opening of the equatorial Atlantic Ocean. Over the last 70 million years, these volcanic islands have been displaced from South America by sea-floor spreading, at a rate of about 2 cm/year. A population-specific instinct to migrate to Ascension Island is thus proposed to have evolved gradually over tens of millions of years of genetic isolation. Here we critically test the Carr-Coleman hypothesis by assaying genetic divergence among several widely separated green turtle rookeries. We have found fixed or nearly fixed mitochondrial DNA (mtDNA) restriction site differences between some Atlantic rookeries, suggesting a severe restriction on contemporary gene flow. Data are consistent with a natal homing hypothesis. However, an extremely close similarity in overall mtDNA sequences of surveyed Atlantic green turtles from three rookeries is incompatible with the Carr-Coleman scenario. The colonization of Ascension Island, or at least extensive gene flow into the population, has been evolutionarily recent. Images PMID:16594013

Effectiveness of nest site restoration for the endangered northern map turtle : report 2 : use of artificial nesting sites and wildlife exclusion fence to enhance nesting success.

DOT National Transportation Integrated Search

2016-10-01

The Northern Map Turtle, Graptemys geographica, is a Maryland state endangered species, found only in the lower Susquehanna River in Maryland. The only area where nests of this species are not heavily impacted by predators occurs in the town of Port ...

Estimates of vital rates for a declining loggerhead turtle (Caretta caretta) subpopulation: implications for management

USGS Publications Warehouse

Lamont, Margaret M.; Fujisaki, Ikuko; Carthy, Raymond R.

2014-01-01

Because subpopulations can differ geographically, genetically and/or phenotypically, using data from one subpopulation to derive vital rates for another, while often unavoidable, is not optimal. We used a two-state open robust design model to analyze a 14-year dataset (1998–2011) from the St. Joseph Peninsula, Florida (USA; 29.748°, −85.400°) which is the densest loggerhead (Caretta caretta) nesting beach in the Northern Gulf of Mexico subpopulation. For these analyses, 433 individuals were marked of which only 7.2 % were observed re-nesting in the study area in subsequent years during the study period. Survival was estimated at 0.86 and is among the highest estimates for all subpopulations in the Northwest Atlantic population. The robust model estimated a nesting assemblage size that ranged from 32 to 230 individuals each year with an annual average of 110. The model estimates indicated an overall population decline of 17 %. The results presented here for this nesting group represent the first estimates for this subpopulation. These data provide managers with information specific to this subpopulation that can be used to develop recovery plans and conduct subpopulation-specific modeling exercises explicit to the challenges faced by turtles nesting in this region.

Measuring the effects of morphological changes to sea turtle nesting beaches over time with LiDAR data

NASA Astrophysics Data System (ADS)

Yamamoto, Kristina H.; Anderson, Sharolyn J.; Sutton, Paul C.

2015-10-01

Sea turtle nesting beaches in southeastern Florida were evaluated for changes from 1999 to 2005 using LiDAR datasets. Changes to beach volume were correlated with changes in several elevation-derived characteristics, such as elevation and slope. In addition, these changes to beach geomorphology were correlated to changes in nest success, illustrating that beach alterations may affect sea turtle nesting behavior. The ability to use LiDAR datasets to quickly and efficiently conduct beach comparisons for habitat use represents another benefit to this high spatial resolution data.

Effects of rising temperature on the viability of an important sea turtle rookery

NASA Astrophysics Data System (ADS)

Laloë, Jacques-Olivier; Cozens, Jacquie; Renom, Berta; Taxonera, Albert; Hays, Graeme C.

2014-06-01

A warming world poses challenges for species with temperature-dependent sex determination, including sea turtles, for which warmer incubation temperatures produce female hatchlings. We combined in situ sand temperature measurements with air temperature records since 1850 and predicted warming scenarios from the Intergovernmental Panel on Climate Change to derive 250-year time series of incubation temperatures, hatchling sex ratios, and operational sex ratios for one of the largest sea turtles rookeries globally (Cape Verde Islands, Atlantic). We estimate that light-coloured beaches currently produce 70.10% females whereas dark-coloured beaches produce 93.46% females. Despite increasingly female skewed sex ratios, entire feminization of this population is not imminent. Rising temperatures increase the number of breeding females and hence the natural rate of population growth. Predicting climate warming impacts across hatchlings, male-female breeding ratios and nesting numbers provides a holistic approach to assessing the conservation concerns for sea turtles in a warming world.

Swimming against the tide: resilience of a riverine turtle to recurrent extreme environmental events.

PubMed

Jergenson, Abigail M; Miller, David A W; Neuman-Lee, Lorin A; Warner, Daniel A; Janzen, Fredric J

2014-03-01

Extreme environmental events (EEEs) are likely to exert deleterious effects on populations. From 1996 to 2012 we studied the nesting dynamics of a riverine population of painted turtles (Chrysemys picta) that experienced seven years with significantly definable spring floods. We used capture-mark-recapture methods to estimate the relationships between more than 5 m and more than 6 m flood events and population parameters. Contrary to expectations, flooding was not associated with annual differences in survival, recruitment or annual population growth rates of the adult female segment of the population. These findings suggest that female C. picta exhibit resiliency to key EEE, which are expected to increase in frequency under climate change.

Evidence for geomagnetic imprinting and magnetic navigation in the natal homing of sea turtles.

PubMed

Brothers, J Roger; Lohmann, Kenneth J

2015-02-02

Natal homing is a pattern of behavior in which animals migrate away from their geographic area of origin and then return to reproduce in the same location where they began life [1-3]. Although diverse long-distance migrants accomplish natal homing [1-8], little is known about how they do so. The enigma is epitomized by loggerhead sea turtles (Caretta caretta), which leave their home beaches as hatchlings and migrate across entire ocean basins before returning to nest in the same coastal area where they originated [9, 10]. One hypothesis is that turtles imprint on the unique geomagnetic signature of their natal area and use this information to return [1]. Because Earth's field changes over time, geomagnetic imprinting should cause turtles to change their nesting locations as magnetic signatures drift slightly along coastlines. To investigate, we analyzed a 19-year database of loggerhead nesting sites in the largest sea turtle rookery in North America. Here we report a strong association between the spatial distribution of turtle nests and subtle changes in Earth's magnetic field. Nesting density increased significantly in coastal areas where magnetic signatures of adjacent beach locations converged over time, whereas nesting density decreased in places where magnetic signatures diverged. These findings confirm central predictions of the geomagnetic imprinting hypothesis and provide strong evidence that such imprinting plays an important role in natal homing in sea turtles. The results give credence to initial reports of geomagnetic imprinting in salmon [11, 12] and suggest that similar mechanisms might underlie long-distance natal homing in diverse animals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Traditional Beach Template vs Cross Shore Swash Zone (CSSZ) Placement Methods at Egmont Key, FL: High Silt Content Beneficial Use Placement

DTIC Science & Technology

2015-10-15

Munsell Color • Light Attenuation and Turbidity • Sea turtle nesting • Conclusions • Traditional vs. Cross Shore Swash Zone Placement • Acknowledgments...Light Attenuation Long-term Monitoring Dredging 19 Nov. – 28 Dec. Dredging 21 Jan. – 6 Mar. BUILDING STRONG® Sea Turtle Nesting 2015 Traditional...Traditional Placement • Less linear feet of beach impacted for equivalent volume • Reduced environmental Impacts • Turtle nest relocations • Ponding

Effectiveness of nest site restoration for the endangered northern map turtle. Report no. 1 : nest site selection and nest success from 2013-2014 and establishment of environmental center : [research summary].

DOT National Transportation Integrated Search

2015-05-01

The Northern Map Turtle, Graptemys geographica, is a Maryland state : Endangered Species, found only in the lower Susquehanna River in Maryland. : The only area where nests of this species are not heavily impacted by predators : occurs in the town of...

Effectiveness of nest site restoration for the endangered northern map turtle. Report no. 1 : nest site selection and nest success from 2013-2014 and establishment of environmental center.

DOT National Transportation Integrated Search

2015-05-01

The Northern Map Turtle, Graptemys geographica, is a Maryland state Endangered Species, found only in the : lower Susquehanna River in Maryland. The only area where nests of this species are not heavily impacted by : predators occurs in the town of P...

Baseline plasma corticosterone, haematological and biochemical results in nesting and rehabilitating loggerhead sea turtles (Caretta caretta)

PubMed Central

Flower, Jennifer E.; Norton, Terry M.; Andrews, Kimberly M.; Nelson, Steven E.; Parker, Clare E.; Romero, L. Michael; Mitchell, Mark A.

2015-01-01

The evaluation of hormonal responses to stress in reptiles relies on acquisition of baseline corticosterone concentrations; however, the stress associated with the restraint needed to collect the blood samples can affect the results. The purpose of this study was to determine a time limit for the collection of blood samples to evaluate baseline corticosterone, haematological and biochemical results in nesting (n = 11) and rehabilitating (n = 16) loggerhead sea turtles (Caretta caretta). Blood samples were collected from the dorsal cervical sinus of each turtle immediately after touching the animal (t0; 0–3 min) and 3 (t3; 3–6 min), 6 (t6; 6–9 min; nesting turtles only), 10 (t10; 10–13 min) and 30 min (t30; rehabilitating turtles only) after the initial hands-on time. Consistent between the rehabilitating and nesting turtles, there was a subtle yet significant increase in white blood cell counts over time. Despite the fact that white blood cell counts increased during the sampling period, there was no direct correlation between white blood cell count and corticosterone in the sampled turtles. In the nesting turtles, significant elevations in corticosterone were noted between t0 and t3 (P = 0.014) and between t0 and t6 (P = 0.022). Values at t10 were not significantly different from those at t0 (P = 0.102); however, there was a trend for the corticosterone values to continue to increase. These results suggest that sampling of nesting loggerhead sea turtles within 3 min of handling will provide baseline corticosterone concentrations in their natural environment. Significant elevations in corticosterone were also noted in the rehabilitating loggerhead sea turtles between t0 and t10 (P = 0.02) and between t0 and t30 of sampling (P = 0.0001). These results suggest that sampling of loggerhead sea turtles within 6 min of handling should provide baseline corticosterone concentrations in a rehabilitation setting. The delay in the corticosterone response noted in the rehabilitating turtles may be associated with the daily contact (visual or direct) they have with their human caretakers. PMID:27293688

Reconstructing paternal genotypes to infer patterns of sperm storage and sexual selection in the hawksbill turtle.

PubMed

Phillips, Karl P; Jorgensen, Tove H; Jolliffe, Kevin G; Jolliffe, San-Marie; Henwood, Jock; Richardson, David S

2013-04-01

Postcopulatory sperm storage can serve a range of functions, including ensuring fertility, allowing delayed fertilization and facilitating sexual selection. Sperm storage is likely to be particularly important in wide-ranging animals with low population densities, but its prevalence and importance in such taxa, and its role in promoting sexual selection, are poorly known. Here, we use a powerful microsatellite array and paternal genotype reconstruction to assess the prevalence of sperm storage and test sexual selection hypotheses of genetic biases to paternity in one such species, the critically endangered hawksbill turtle, Eretmochelys imbricata. In the majority of females (90.7%, N = 43), all offspring were sired by a single male. In the few cases of multiple paternity (9.3%), two males fertilized each female. Importantly, the identity and proportional fertilization success of males were consistent across all sequential nests laid by individual females over the breeding season (up to five nests over 75 days). No males were identified as having fertilized more than one female, suggesting that a large number of males are available to females. No evidence for biases to paternity based on heterozygosity or relatedness was found. These results indicate that female hawksbill turtles are predominantly monogamous within a season, store sperm for the duration of the nesting season and do not re-mate between nests. Furthermore, females do not appear to be using sperm storage to facilitate sexual selection. Consequently, the primary value of storing sperm in marine turtles may be to uncouple mating and fertilization in time and avoid costly re-mating. © 2013 Blackwell Publishing Ltd.

Individual-level behavioral responses of immature green turtles to snorkeler disturbance.

PubMed

Griffin, Lucas P; Brownscombe, Jacob W; Gagné, Tyler O; Wilson, Alexander D M; Cooke, Steven J; Danylchuk, Andy J

2017-03-01

Despite many positive benefits of ecotourism, increased human encounters with wildlife may have detrimental effects on wild animals. As charismatic megafauna, nesting and foraging sea turtles are increasingly the focus of ecotourism activities. The purpose of our study was to quantify the behavioral responses of immature green turtles (Chelonia mydas) to disturbance by snorkelers, and to investigate whether turtles have individual-level responses to snorkeler disturbance. Using a standardized disturbance stimulus in the field, we recorded turtle behaviors pre- and post-disturbance by snorkelers. Ninety percent of turtles disturbed by snorkeler (n = 192) initiated their flights at distances of ≤3 m. Using principal component analysis, we identified two distinct turtle personality types, 'bold' and 'timid', based upon 145 encounters of 19 individually identified turtles and five disturbance response variables. There was significant intra-individual repeatability in behavioral responses to disturbance, but bolder turtles had more behavioral plasticity and less consistent responses than more timid individuals. Bolder individuals with reduced evasion responses might be at a higher risk of shark predation, while more timid turtles might have greater energetic consequences due to non-lethal predator effects and repeated snorkeler disturbance. Over the longer term, a turtle population with a mix of bold and timid individuals may promote more resilient populations. We recommend that snorkelers maintain >3 m distance from immature green turtles when snorkeling, and that ecotourism activities be temporally and spatially stratified. Further, turtle watching guidelines need to be communicated to both tour operators and independent snorkelers to reduce the disturbance of turtles.

Inheritance of nesting behaviour across natural environmental variation in a turtle with temperature-dependent sex determination.

PubMed

McGaugh, Suzanne E; Schwanz, Lisa E; Bowden, Rachel M; Gonzalez, Julie E; Janzen, Fredric J

2010-04-22

Nesting behaviour is critical for reproductive success in oviparous organisms with no parental care. In organisms where sex is determined by incubation temperature, nesting behaviour may be a prime target of selection in response to unbalanced sex ratios. To produce an evolutionary change in response to sex-ratio selection, components of nesting behaviour must be heritable. We estimated the field heritability of two key components of nesting behaviour in a population of painted turtles (Chrysemys picta) with temperature-dependent sex determination by applying the 'animal model' to a pedigree reconstructed from genotype data. We obtained estimates of low to non-detectable heritability using repeated records across all environments. We then determined environment-specific heritability by grouping records with similar temperatures for the winter preceding the nesting season, a variable known to be highly associated with our two traits of interest, nest vegetation cover and Julian date of nesting. The heritability estimates of nest vegetation cover and Julian date of nesting were qualitatively highest and significant, or nearly so, after hot winters. Additive genetic variance for these traits was not detectable after cold winters. Our analysis suggests that the potential for evolutionary change of nesting behaviour may be dependent on the thermal conditions of the preceding winter, a season that is predicted to be especially subject to climate change.

Reproductive synchrony in a recovering bottlenecked sea turtle population.

PubMed

Plot, Virginie; de Thoisy, Benoît; Blanc, Stéphane; Kelle, Laurent; Lavergne, Anne; Roger-Bérubet, Hélène; Tremblay, Yann; Fossette, Sabrina; Georges, Jean-Yves

2012-03-01

1. The assessment of species extinction risk has been well established for some time now. Assessing the potential for recovery in endangered species is however much more challenging, because complementary approaches are required to detect reliable signals of positive trends. 2. This study combines genetics, demography and behavioural data at three different time-scales to assess historical and recent population changes and evidence of reproductive synchrony in a small population of olive ridley sea turtle Lepidochelys olivacea. Lepidochelys is considered as the most extraordinary example of reproductive synchrony in reptiles, yet to date, it has only been reported in large populations. 3. Using Bayesian coalescent-based models on microsatellite nuclear DNA variability, we demonstrate that effective population size in olive ridleys nesting in French Guiana has dramatically declined by 99% over the last 20 centuries. This low current population size is further illustrated by the absence of genetic mitochondrial DNA diversity in the present nesting population. Yet, monitoring of nesting sites in French Guiana suggests a possible recovery of the population over the last decade. 4. Satellite telemetry shows that over the first 14 days of their 28-days inter-nesting interval, i.e. when eggs maturation is likely to occur, gravid females disperse over the continental shelf. They then gather together with a striking spatiotemporal consistency close to the nesting site, where they later emerge for their second nesting event. 5. Our results therefore suggest that reproductive synchrony also occurs in small populations. Olive ridleys may ensure this synchrony by adjusting the duration of the second half of their inter-nesting interval prior to landing, possibly through social mediation. 6. Such reproductive synchrony may be related to the maintenance of some species-specific strategy despite former collapse and may contribute to the present population recovery. The gregarious behaviour of reproductive individuals close to shore where human-induced perturbations occur is however a cause for conservation concern for this still poorly known species. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.

Development of a Kemp’s ridley sea turtle stock assessment model

USGS Publications Warehouse

Gallaway, Benny J.; Gazey, William; Caillouet, Charles W.; Plotkin, Pamela T.; Abreu Grobois, F. Alberto; Amos, Anthony F.; Burchfield, Patrick M.; Carthy, Raymond R.; Castro Martinez, Marco A.; Cole, John G.; Coleman, Andrew T.; Cook, Melissa; DiMarco, Steven F.; Epperly, Sheryan P.; Fujiwara, Masami; Gamez, Daniel Gomez; Graham, Gary L.; Griffin, Wade L.; Illescas Martinez, Francisco; Lamont, Margaret M.; Lewison, Rebecca L.; Lohmann, Kenneth J.; Nance, James M.; Pitchford, Jonathan; Putman, Nathan F.; Raborn, Scott W.; Rester, Jeffrey K.; Rudloe, Jack J.; Sarti Martinez, Laura; Schexnayder, Mark; Schmid, Jeffrey R.; Shaver, Donna J.; Slay, Christopher; Tucker, Anton D.; Tumlin, Mandy; Wibbels, Thane; Zapata Najera, Blanca M.

2016-01-01

We developed a Kemp’s ridley (Lepidochelys kempii) stock assessment model to evaluate the relative contributions of conservation efforts and other factors toward this critically endangered species’ recovery. The Kemp’s ridley demographic model developed by the Turtle Expert Working Group (TEWG) in 1998 and 2000 and updated for the binational recovery plan in 2011 was modified for use as our base model. The TEWG model uses indices of the annual reproductive population (number of nests) and hatchling recruitment to predict future annual numbers of nests on the basis of a series of assumptions regarding age and maturity, remigration interval, sex ratios, nests per female, juvenile mortality, and a putative ‘‘turtle excluder device effect’’ multiplier starting in 1990. This multiplier was necessary to fit the number of nests observed in 1990 and later. We added the effects of shrimping effort directly, modified by habitat weightings, as a proxy for all sources of anthropogenic mortality. Additional data included in our model were incremental growth of Kemp’s ridleys marked and recaptured in the Gulf of Mexico, and the length frequency of stranded Kemp’s ridleys. We also added a 2010 mortality factor that was necessary to fit the number of nests for 2010 and later (2011 and 2012). Last, we used an empirical basis for estimating natural mortality, on the basis of a Lorenzen mortality curve and growth estimates. Although our model generated reasonable estimates of annual total turtle deaths attributable to shrimp trawling, as well as additional deaths due to undetermined anthropogenic causes in 2010, we were unable to provide a clear explanation for the observed increase in the number of stranded Kemp’s ridleys in recent years, and subsequent disruption of the species’ exponential growth since the 2009 nesting season. Our consensus is that expanded data collection at the nesting beaches is needed and of high priority, and that 2015 be targeted for the next stock assessment to evaluate the 2010 event using more recent nesting and in-water data.

Profiles of environmental contaminants in hawksbill turtle egg yolks reflect local to distant pollution sources among nesting beaches in the Yucatán Peninsula, Mexico.

PubMed

Muñoz, Cynthia C; Vermeiren, Peter

2018-04-01

Knowledge of spatial variation in pollutant profiles among sea turtle nesting locations is limited. This poses challenges in identifying processes shaping this variability and sets constraints to the conservation management of sea turtles and their use as biomonitoring tools for environmental pollutants. We aimed to increase understanding of the spatial variation in polycyclic aromatic hydrocarbon (PAH), organochlorine pesticide (OCP) and polychlorinated biphenyl (PCB) compounds among nesting beaches. We link the spatial variation to turtle migration patterns and the persistence of these pollutants. Specifically, using gas chromatography, we confirmed maternal transfer of a large number of compounds (n = 68 out of 69) among 104 eggs collected from 21 nests across three nesting beaches within the Yucatán Peninsula, one of the world's most important rookeries for hawksbill turtles (Eretmochelys imbricata). High variation in PAH profiles was observed among beaches, using multivariate correspondence analysis and univariate Peto-Prentice tests, reflecting local acquisition during recent migration movements. Diagnostic PAH ratios reflected petrogenic origins in Celestún, the beach closest to petroleum industries in the Gulf of Mexico. By contrast, pollution profiles of OCPs and PCBs showed high similarity among beaches, reflecting the long-term accumulation of these pollutants at regional scales. Therefore, spatial planning of protected areas and the use of turtle eggs in biomonitoring needs to account for the spatial variation in pollution profiles among nesting beaches. Copyright © 2018 Elsevier Ltd. All rights reserved.

Inter-nesting habitat-use patterns of loggerhead sea turtles: Enhancing satellite tracking with benthic mapping

USGS Publications Warehouse

Hart, Kristen M.; Zawada, David G.; Fujisaki, Ikuko; Lidz, Barbara H.

2010-01-01

The loggerhead sea turtle Caretta caretta faces declining nest numbers and bycatches from commercial longline fishing in the southeastern USA. Understanding spatial and temporal habitat-use patterns of these turtles, especially reproductive females in the neritic zone, is critical for guiding management decisions. To assess marine turtle habitat use within the Dry Tortugas National Park (DRTO), we used satellite telemetry to identify core-use areas for 7 loggerhead females inter-nesting and tracked in 2008 and 2009. This effort represents the first tracking of DRTO loggerheads, a distinct subpopulation that is 1 of 7 recently proposed for upgrading from threatened to endangered under the US Endangered Species Act. We also used a rapid, high-resolution, digital imaging system to map benthic habitats in turtle core-use areas (i.e. 50% kernel density zones). Loggerhead females were seasonal residents of DRTO for 19 to 51 d, and individual inter-nesting habitats were located within 1.9 km (2008) and 2.3 km (2009) of the nesting beach and tagging site. The core area common to all tagged turtles was 4.2 km2 in size and spanned a depth range of 7.6 to 11.5 m. Mapping results revealed the diversity and distributions of benthic cover available in the core-use area, as well as a heavily used corridor to/from the nesting beach. This combined tagging-mapping approach shows potential for planning and improving the effectiveness of marine protected areas and for developing spatially explicit conservation plans.

Light pollution affects nesting behavior of loggerhead turtles and predation risk of nests and hatchlings.

PubMed

Silva, Elton; Marco, Adolfo; da Graça, Jesemine; Pérez, Héctor; Abella, Elena; Patino-Martinez, Juan; Martins, Samir; Almeida, Corrine

2017-08-01

The introduction of artificial light into wildlife habitats is a rapidly expanding aspect of global change, which has many negative impacts on a wide range of taxa. In this experimental study, which took place on a beach located on the island of Boa Vista (Cabo Verde), three types of artificial light were tested on nesting loggerhead sea turtles as well as on ghost crabs, which intensively predate on nests and hatchlings, to determine the effects they would produce on the behavior of both species. Over the course of 36days, female loggerheads and ghost crabs were studied under yellow, orange and red lights, with observations also being made on dark nights that served as a control treatment. During this period, the frequencies of nesting attempts, the time taken by turtles to complete each phase of the nesting process, and ghost crab abundance and behaviors were carefully recorded. 1146 loggerhead nesting attempts were observed and recorded during the experiments, and results showed a decrease in nesting attempts of at least 20% when artificial lighting was present. A significant decline in successful attempts was also observed within the central sections of the beach, which corresponded to those that received more light. This artificial lighting significantly increased the time that turtles spent on the nesting process and forced them to do more extensive beach crawls. Despite this, the presence of light had no apparent effect on the final selection of the nesting site. Yellow and orange lights significantly disrupted the sea finding behavior and turtles were often unable to orient themselves seaward under these color lights. Disoriented turtles were observed crawling in circuitous paths in front of the light source for several minutes. In addition, artificial lights had the potential to increase the number of ghost crabs present within the illuminated stretches of the beach. However, only yellow lighting produced a significant change on aggressive and prey searching behaviors. These changes in abundance and behavior could cause a greater predation on loggerhead turtle nests. Red light had no significant impact on the behavior of either species. It should be a priority to enforce preventive measures and light mitigation strategies to ensure the conservation of important loggerhead rookeries. Copyright © 2017 Elsevier B.V. All rights reserved.

Evidence that Magnetic Navigation and Geomagnetic Imprinting Shape Spatial Genetic Variation in Sea Turtles.

PubMed

Brothers, J Roger; Lohmann, Kenneth J

2018-04-23

The canonical drivers of population genetic structure, or spatial genetic variation, are isolation by distance and isolation by environment. Isolation by distance predicts that neighboring populations will be genetically similar and geographically distant populations will be genetically distinct [1]. Numerous examples also exist of isolation by environment, a phenomenon in which populations that inhabit similar environments (e.g., same elevation, temperature, or vegetation) are genetically similar even if they are distant, whereas populations that inhabit different environments are genetically distinct even when geographically close [2-4]. These dual models provide a widely accepted conceptual framework for understanding population structure [5-8]. Here, we present evidence for an additional, novel process that we call isolation by navigation, in which the navigational mechanism used by a long-distance migrant influences population structure independently of isolation by either distance or environment. Specifically, we investigated the population structure of loggerhead sea turtles (Caretta caretta) [9], which return to nest on their natal beaches by seeking out unique magnetic signatures along the coast-a behavior known as geomagnetic imprinting [10-12]. Results reveal that spatial variation in Earth's magnetic field strongly predicts genetic differentiation between nesting beaches, even when environmental similarities and geographic proximity are taken into account. The findings provide genetic corroboration of geomagnetic imprinting [10, 13]. Moreover, they provide strong evidence that geomagnetic imprinting and magnetic navigation help shape the population structure of sea turtles and perhaps numerous other long-distance migrants that return to their natal areas to reproduce [13-17]. Copyright © 2018 Elsevier Ltd. All rights reserved.

Temporal, spatial, and body size effects on growth rates of loggerhead sea turtles (Caretta caretta) in the Northwest Atlantic

USGS Publications Warehouse

Bjorndal, Karen A.; Schroeder, Barbara A.; Foley, Allen M.; Witherington, Blair E.; Bresette, Michael; Clark, David; Herren, Richard M.; Arendt, Michael D.; Schmid, Jeffrey R.; Meylan, Anne B.; Meylan, Peter A.; Provancha, Jane A.; Hart, Kristen M.; Lamont, Margaret M.; Carthy, Raymond R.; Bolten, Alan B.

2013-01-01

In response to a call from the US National Research Council for research programs to combine their data to improve sea turtle population assessments, we analyzed somatic growth data for Northwest Atlantic (NWA) loggerhead sea turtles (Caretta caretta) from 10 research programs. We assessed growth dynamics over wide ranges of geography (9–33°N latitude), time (1978–2012), and body size (35.4–103.3 cm carapace length). Generalized additive models revealed significant spatial and temporal variation in growth rates and a significant decline in growth rates with increasing body size. Growth was more rapid in waters south of the USA (<24°N) than in USA waters. Growth dynamics in southern waters in the NWA need more study because sample size was small. Within USA waters, the significant spatial effect in growth rates of immature loggerheads did not exhibit a consistent latitudinal trend. Growth rates declined significantly from 1997 through 2007 and then leveled off or increased. During this same interval, annual nest counts in Florida declined by 43 % (Witherington et al. in Ecol Appl 19:30–54, 2009) before rebounding. Whether these simultaneous declines reflect responses in productivity to a common environmental change should be explored to determine whether somatic growth rates can help interpret population trends based on annual counts of nests or nesting females. Because of the significant spatial and temporal variation in growth rates, population models of NWA loggerheads should avoid employing growth data from restricted spatial or temporal coverage to calculate demographic metrics such as age at sexual maturity.

Isolation by environment in the highly mobile olive ridley turtle (Lepidochelys olivacea) in the eastern Pacific.

PubMed

Rodríguez-Zárate, Clara J; Sandoval-Castillo, Jonathan; van Sebille, Erik; Keane, Robert G; Rocha-Olivares, Axayácatl; Urteaga, Jose; Beheregaray, Luciano B

2018-05-16

Spatial and temporal scales at which processes modulate genetic diversity over the landscape are usually overlooked, impacting the design of conservation management practices for widely distributed species. We examine processes shaping population divergence in highly mobile species by re-assessing the case of panmixia in the iconic olive ridley turtle from the eastern Pacific. We implemented a biophysical model of connectivity and a seascape genetic analysis based on nuclear DNA variation of 634 samples collected from 27 nesting areas. Two genetically distinct populations largely isolated during reproductive migrations and mating were detected, each composed of multiple nesting sites linked by high connectivity. This pattern was strongly associated with a steep environmental gradient and also influenced by ocean currents. These findings relate to meso-scale features of a dynamic oceanographic interface in the eastern tropical Pacific (ETP) region, a scenario that possibly provides different cost-benefit solutions and selective pressures for sea turtles during both the mating and migration periods. We reject panmixia and propose a new paradigm for olive ridley turtles where reproductive isolation due to assortative mating is linked to its environment. Our study demonstrates the relevance of integrative approaches for assessing the role of environmental gradients and oceanographic currents as drivers of genetic differentiation in widely distributed marine species. This is relevant for the conservation management of species of highly mobile behaviour, and assists the planning and development of large-scale conservation strategies for the threatened olive ridley turtles in the ETP. © 2018 The Author(s).

Swimming against the tide: resilience of a riverine turtle to recurrent extreme environmental events

PubMed Central

Jergenson, Abigail M.; Miller, David A. W.; Neuman-Lee, Lorin A.; Warner, Daniel A.; Janzen, Fredric J.

2014-01-01

Extreme environmental events (EEEs) are likely to exert deleterious effects on populations. From 1996 to 2012 we studied the nesting dynamics of a riverine population of painted turtles (Chrysemys picta) that experienced seven years with significantly definable spring floods. We used capture–mark–recapture methods to estimate the relationships between more than 5 m and more than 6 m flood events and population parameters. Contrary to expectations, flooding was not associated with annual differences in survival, recruitment or annual population growth rates of the adult female segment of the population. These findings suggest that female C. picta exhibit resiliency to key EEE, which are expected to increase in frequency under climate change. PMID:24621555

Studies of reproductive output of the desert tortoise at Joshua Tree National Park, the Mojave National Preserve, and comparative sites

USGS Publications Warehouse

Lovich, J.E.; Medica, P.; Avery, H.; Meyer, K.; Bowser, G.; Brown, A.

1999-01-01

The stability of any population is a function of how many young are produced and how many survive to reproduce. Populations with low reproductive output and high mortality will decline until such time as deaths and births are at least balanced. Monitoring populations of sensitive species is particularly important to ensure that conditions do not favor decline or extinction. Turtles, including tortoises, are characterized by life history traits that make them slow to adapt to rapid changes in mortality and habitat alteration. Long life spans (in excess of 50 years), late maturity, and widely variable nest success are traits that allowed turtles to outlive the dinosaurs, but they are poorly adapted for life in the rapidly changing modern world. Increased mortality of young and adults can seriously tip the delicate balance required for turtles to survive.

Marine turtles used to assist Austronesian sailors reaching new islands.

PubMed

Wilmé, Lucienne; Waeber, Patrick O; Ganzhorn, Joerg U

2016-02-01

Austronesians colonized the islands of Rapa Nui, Hawaii, the Marquesas and Madagascar. All of these islands have been found to harbor Austronesian artifacts and also, all of them are known nesting sites for marine turtles. Turtles are well known for their transoceanic migrations, sometimes totalling thousands of miles, between feeding and nesting grounds. All marine turtles require land for nesting. Ancient Austronesians are known to have had outstanding navigation skills, which they used to adjust course directions. But these skills will have been insufficient to locate tiny, remote islands in the vast Indo-Pacific oceans. We postulate that the Austronesians must have had an understanding of the marine turtles' migration patterns and used this knowledge to locate remote and unknown islands. The depth and speed at which marine turtles migrate makes following them by outrigger canoes feasible. Humans have long capitalized on knowledge of animal behavior. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Recent Demographic History and Present Fine-Scale Structure in the Northwest Atlantic Leatherback (Dermochelys coriacea) Turtle Population

PubMed Central

Molfetti, Érica; Torres Vilaça, Sibelle; Georges, Jean-Yves; Plot, Virginie; Delcroix, Eric; Le Scao, Rozen; Lavergne, Anne; Barrioz, Sébastien; dos Santos, Fabrício Rodrigues; de Thoisy, Benoît

2013-01-01

The leatherback turtle Dermochelys coriacea is the most widely distributed sea turtle species in the world. It exhibits complex life traits: female homing and migration, migrations of juveniles and males that remain poorly known, and a strong climatic influence on resources, breeding success and sex-ratio. It is consequently challenging to understand population dynamics. Leatherbacks are critically endangered, yet the group from the Northwest Atlantic is currently considered to be under lower risk than other populations while hosting some of the largest rookeries. Here, we investigated the genetic diversity and the demographic history of contrasted rookeries from this group, namely two large nesting populations in French Guiana, and a smaller one in the French West Indies. We used 10 microsatellite loci, of which four are newly isolated, and mitochondrial DNA sequences of the control region and cytochrome b. Both mitochondrial and nuclear markers revealed that the Northwest Atlantic stock of leatherbacks derives from a single ancestral origin, but show current genetic structuration at the scale of nesting sites, with the maintenance of migrants amongst rookeries. Low nuclear genetic diversities are related to founder effects that followed consequent bottlenecks during the late Pleistocene/Holocene. Most probably in response to climatic oscillations, with a possible influence of early human hunting, female effective population sizes collapsed from 2 million to 200. Evidence of founder effects and high numbers of migrants make it possible to reconsider the population dynamics of the species, formerly considered as a metapopulation model: we propose a more relaxed island model, which we expect to be a key element in the currently observed recovering of populations. Although these Northwest Atlantic rookeries should be considered as a single evolutionary unit, we stress that local conservation efforts remain necessary since each nesting site hosts part of the genetic diversity and species history. PMID:23516429

75 FR 47825 - Emergency Exemption; Issuance of Emergency Permit to Rehabilitate Sea Turtles Affected by the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-09

... tag live sea turtles; transport live and dead sea turtles to rehabilitation facilities, satellite transmitter attachment sites, and necropsy sites and necropsy dead sea turtles and collect samples; examine gut contents from dead sea turtles; attach satellite transmitters to nesting Kemp's ridley turtles...

Embryonic death is linked to maternal identity in the leatherback turtle (Dermochelys coriacea).

PubMed

Rafferty, Anthony R; Santidrián Tomillo, Pilar; Spotila, James R; Paladino, Frank V; Reina, Richard D

2011-01-01

Leatherback turtles have an average global hatching success rate of ~50%, lower than other marine turtle species. Embryonic death has been linked to environmental factors such as precipitation and temperature, although, there is still a lot of variability that remains to be explained. We examined how nesting season, the time of nesting each season, the relative position of each clutch laid by each female each season, maternal identity and associated factors such as reproductive experience of the female (new nester versus remigrant) and period of egg retention between clutches (interclutch interval) affected hatching success and stage of embryonic death in failed eggs of leatherback turtles nesting at Playa Grande, Costa Rica. Data were collected during five nesting seasons from 2004/05 to 2008/09. Mean hatching success was 50.4%. Nesting season significantly influenced hatching success in addition to early and late stage embryonic death. Neither clutch position nor nesting time during the season had a significant affect on hatching success or the stage of embryonic death. Some leatherback females consistently produced nests with higher hatching success rates than others. Remigrant females arrived earlier to nest, produced more clutches and had higher rates of hatching success than new nesters. Reproductive experience did not affect stage of death or the duration of the interclutch interval. The length of interclutch interval had a significant affect on the proportion of eggs that failed in each clutch and the developmental stage they died at. Intrinsic factors such as maternal identity are playing a role in affecting embryonic death in the leatherback turtle.

Core and body surface temperatures of nesting leatherback turtles (Dermochelys coriacea).

PubMed

Burns, Thomas J; McCafferty, Dominic J; Kennedy, Malcolm W

2015-07-01

Leatherback turtles (Dermochelys coriacea) are the largest species of marine turtle and the fourth most massive extant reptile. In temperate waters they maintain body temperatures higher than surrounding seawater through a combination of insulation, physiological, and behavioural adaptations. Nesting involves physical activity in addition to contact with warm sand and air, potentially presenting thermal challenges in the absence of the cooling effect of water, and data are lacking with which to understand their nesting thermal biology. Using non-contact methods (thermal imaging and infrared thermometry) to avoid any stress-related effects, we investigated core and surface temperature during nesting. The mean±SE core temperature was 31.4±0.05°C (newly emerged eggs) and was not correlated with environmental conditions on the nesting beach. Core temperature of leatherbacks was greater than that of hawksbill turtles (Eretmochelys imbricata) nesting at a nearby colony, 30.0±0.13°C. Body surface temperatures of leatherbacks showed regional variation, the lateral and dorsal regions of the head were warmest while the carapace was the coolest surface. Surface temperature increased during the early nesting phases, then levelled off or decreased during later phases with the rates of change varying between body regions. Body region, behavioural phase of nesting and air temperature were found to be the best predictors of surface temperature. Regional variation in surface temperature were likely due to alterations in blood supply, and temporal changes in local muscular activity of flippers during the different phases of nesting. Heat exchange from the upper surface of the turtle was dominated by radiative heat loss from all body regions and small convective heat gains to the carapace and front flippers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Inter-nesting movements and habitat-use of adult female Kemp’s ridley turtles in the Gulf of Mexico

USGS Publications Warehouse

Shaver, Donna J.; Hart, Kristen M.; Fujisaki, Ikuko; Bucklin, David N.; Iverson, Autumn; Rubio, Cynthia; Backof, Thomas F.; Burchfield, Patrick M.; Gonzales Diaz Miron, Raul de Jesus; Dutton, Peter H.; Frey, Amy; Peña, Jaime; Gamez, Daniel Gomez; Martinez, Hector J.; Ortiz, Jaime

2017-01-01

Species vulnerability is increased when individuals congregate in restricted areas for breeding; yet, breeding habitats are not well defined for many marine species. Identification and quantification of these breeding habitats are essential to effective conservation. Satellite telemetry and switching state-space modeling (SSM) were used to define inter-nesting habitat of endangered Kemp’s ridley turtles (Lepidochelys kempii) in the Gulf of Mexico. Turtles were outfitted with satellite transmitters after nesting at Padre Island National Seashore, Texas, USA, from 1998 through 2013 (n = 60); Rancho Nuevo, Tamaulipas, Mexico, during 2010 and 2011 (n = 11); and Tecolutla, Veracruz, Mexico, during 2012 and 2013 (n = 11). These sites span the range of nearly all nesting by this species. Inter-nesting habitat lies in a narrow band of nearshore western Gulf of Mexico waters in the USA and Mexico, with mean water depth of 14 to 19 m within a mean distance to shore of 6 to 11 km as estimated by 50% kernel density estimate, α-Hull, and minimum convex polygon methodologies. Turtles tracked during the inter-nesting period moved, on average, 17.5 km/day and a mean total distance of 398 km. Mean home ranges occupied were 725 to 2948 km2. Our results indicate that these nearshore western Gulf waters represent critical inter-nesting habitat for this species, where threats such as shrimp trawling and oil and gas platforms also occur. Up to half of all adult female Kemp’s ridleys occupy this habitat for weeks to months during each nesting season. Because inter-nesting habitat for this species is concentrated in nearshore waters of the western Gulf of Mexico in both Mexico and the USA, international collaboration is needed to protect this essential habitat and the turtles occurring within it.

Inter-nesting movements and habitat-use of adult female Kemp's ridley turtles in the Gulf of Mexico.

PubMed

Shaver, Donna J; Hart, Kristen M; Fujisaki, Ikuko; Bucklin, David; Iverson, Autumn R; Rubio, Cynthia; Backof, Thomas F; Burchfield, Patrick M; de Jesus Gonzales Diaz Miron, Raul; Dutton, Peter H; Frey, Amy; Peña, Jaime; Gomez Gamez, Daniel; Martinez, Hector J; Ortiz, Jaime

2017-01-01

Species vulnerability is increased when individuals congregate in restricted areas for breeding; yet, breeding habitats are not well defined for many marine species. Identification and quantification of these breeding habitats are essential to effective conservation. Satellite telemetry and switching state-space modeling (SSM) were used to define inter-nesting habitat of endangered Kemp's ridley turtles (Lepidochelys kempii) in the Gulf of Mexico. Turtles were outfitted with satellite transmitters after nesting at Padre Island National Seashore, Texas, USA, from 1998 through 2013 (n = 60); Rancho Nuevo, Tamaulipas, Mexico, during 2010 and 2011 (n = 11); and Tecolutla, Veracruz, Mexico, during 2012 and 2013 (n = 11). These sites span the range of nearly all nesting by this species. Inter-nesting habitat lies in a narrow band of nearshore western Gulf of Mexico waters in the USA and Mexico, with mean water depth of 14 to 19 m within a mean distance to shore of 6 to 11 km as estimated by 50% kernel density estimate, α-Hull, and minimum convex polygon methodologies. Turtles tracked during the inter-nesting period moved, on average, 17.5 km/day and a mean total distance of 398 km. Mean home ranges occupied were 725 to 2948 km2. Our results indicate that these nearshore western Gulf waters represent critical inter-nesting habitat for this species, where threats such as shrimp trawling and oil and gas platforms also occur. Up to half of all adult female Kemp's ridleys occupy this habitat for weeks to months during each nesting season. Because inter-nesting habitat for this species is concentrated in nearshore waters of the western Gulf of Mexico in both Mexico and the USA, international collaboration is needed to protect this essential habitat and the turtles occurring within it.

Diel foraging behavior of gravid leatherback sea turtles in deep waters of the Caribbean Sea.

PubMed

Casey, James; Garner, Jeanne; Garner, Steve; Williard, Amanda Southwood

2010-12-01

It is generally assumed that leatherback turtles (Dermochelys coriacea), like other species of sea turtle, do not feed while offshore from nesting beaches, and rely instead on fat reserves to fuel reproductive activities. Recent studies, however, provide evidence that leatherbacks may forage during the internesting interval while offshore in the Western Atlantic Ocean and Caribbean Sea. Bio-logging technology was used to investigate the foraging behavior of female leatherback turtles at St Croix, US Virgin Islands. Leatherback gastrointestinal tract temperatures (T(GT)) were analyzed for sudden fluctuations indicative of ingestions, and laboratory ingestion simulations were used to characterize temperature fluctuations associated with ingestion of prey versus seawater. Dive patterns associated with prey ingestion were characterized and the proportion of prey ingestion during the day (05:00-18:59 h) and night (19:00-04:59 h) were compared. A combined total of 111 prey ingestions for seven leatherback turtles were documented during the internesting interval. The number of prey ingestions ranged from six to 48 for individual turtles, and the majority (87.4%) of these events occurred during the daytime. Prey ingestions were most frequently associated with V-shaped dives, and the mean (±1 s.d.) maximum dive depth with prey ingestion ranged from 154±51 to 232±101 m for individual turtles. Although leatherbacks were found to opportunistically feed during the internesting interval, the low prey ingestion rates indicate that energy reserves acquired prior to the breeding season are critical for successful reproduction by leatherbacks from the St Croix, USVI nesting population.

Factors affecting hatch success of hawksbill sea turtles on Long Island, Antigua, West Indies.

PubMed

Ditmer, Mark Allan; Stapleton, Seth Patrick

2012-01-01

Current understanding of the factors influencing hawksbill sea turtle (Eretmochelys imbricata) hatch success is disparate and based on relatively short-term studies or limited sample sizes. Because global populations of hawksbills are heavily depleted, evaluating the parameters that impact hatch success is important to their conservation and recovery. Here, we use data collected by the Jumby Bay Hawksbill Project (JBHP) to investigate hatch success. The JBHP implements saturation tagging protocols to study a hawksbill rookery in Antigua, West Indies. Habitat data, which reflect the varied nesting beaches, are collected at egg deposition, and nest contents are exhumed and categorized post-emergence. We analyzed hatch success using mixed-model analyses with explanatory and predictive datasets. We incorporated a random effect for turtle identity and evaluated environmental, temporal and individual-based reproductive variables. Hatch success averaged 78.6% (SD: 21.2%) during the study period. Highly supported models included multiple covariates, including distance to vegetation, deposition date, individual intra-seasonal nest number, clutch size, organic content, and sand grain size. Nests located in open sand were predicted to produce 10.4 more viable hatchlings per clutch than nests located >1.5 m into vegetation. For an individual first nesting in early July, the fourth nest of the season yielded 13.2 more viable hatchlings than the initial clutch. Generalized beach section and inter-annual variation were also supported in our explanatory dataset, suggesting that gaps remain in our understanding of hatch success. Our findings illustrate that evaluating hatch success is a complex process, involving multiple environmental and individual variables. Although distance to vegetation and hatch success were inversely related, vegetation is an important component of hawksbill nesting habitat, and a more complete assessment of the impacts of specific vegetation types on hatch success and hatchling sex ratios is needed. Future research should explore the roles of sand structure, nest moisture, and local weather conditions.

Factors Affecting Hatch Success of Hawksbill Sea Turtles on Long Island, Antigua, West Indies

PubMed Central

Ditmer, Mark Allan; Stapleton, Seth Patrick

2012-01-01

Current understanding of the factors influencing hawksbill sea turtle (Eretmochelys imbricata) hatch success is disparate and based on relatively short-term studies or limited sample sizes. Because global populations of hawksbills are heavily depleted, evaluating the parameters that impact hatch success is important to their conservation and recovery. Here, we use data collected by the Jumby Bay Hawksbill Project (JBHP) to investigate hatch success. The JBHP implements saturation tagging protocols to study a hawksbill rookery in Antigua, West Indies. Habitat data, which reflect the varied nesting beaches, are collected at egg deposition, and nest contents are exhumed and categorized post-emergence. We analyzed hatch success using mixed-model analyses with explanatory and predictive datasets. We incorporated a random effect for turtle identity and evaluated environmental, temporal and individual-based reproductive variables. Hatch success averaged 78.6% (SD: 21.2%) during the study period. Highly supported models included multiple covariates, including distance to vegetation, deposition date, individual intra-seasonal nest number, clutch size, organic content, and sand grain size. Nests located in open sand were predicted to produce 10.4 more viable hatchlings per clutch than nests located >1.5 m into vegetation. For an individual first nesting in early July, the fourth nest of the season yielded 13.2 more viable hatchlings than the initial clutch. Generalized beach section and inter-annual variation were also supported in our explanatory dataset, suggesting that gaps remain in our understanding of hatch success. Our findings illustrate that evaluating hatch success is a complex process, involving multiple environmental and individual variables. Although distance to vegetation and hatch success were inversely related, vegetation is an important component of hawksbill nesting habitat, and a more complete assessment of the impacts of specific vegetation types on hatch success and hatchling sex ratios is needed. Future research should explore the roles of sand structure, nest moisture, and local weather conditions. PMID:22802928

Dispersal, recruitment and migratory behaviour in a hawksbill sea turtle aggregation.

PubMed

Velez-Zuazo, Ximena; Ramos, Willy D; van Dam, Robert P; Diez, Carlos E; Abreu-Grobois, Alberto; McMillan, W Owen

2008-02-01

We investigated the dispersal, recruitment and migratory behaviour of the hawksbill sea turtle (Eretmochelys imbricata), among different life-history stages and demographic segments of the large hawksbill turtle aggregation at Mona Island, Puerto Rico. There were significant differences in both mitochondrial DNA (mtDNA) haplotype diversity and haplotype frequencies among the adult males, females and juveniles examined, but little evidence for temporal heterogeneity within these same groups sampled across years. Consistent with previous studies and the hypothesis of strong natal homing, there were striking mtDNA haplotype differences between nesting females on Mona Island and nesting females in other major Caribbean rookeries. Breeding males also showed strong, albeit weaker, genetic evidence of natal homing. Overall, Bayesian mixed-stock analysis suggests that Mona Island was the natal rookery for 79% (65-94%) of males in the aggregation. In contrast, the Mona Island rookery accounted for only a small subset of the new juvenile recruits to the foraging grounds or in the population of older juvenile hawksbills turtles on Mona. Instead, both new recruits and the older juvenile hawksbill turtles on Mona more likely recruited from other Caribbean rookeries, suggesting that a mechanism besides natal homing must be influencing recruitment to feeding habitats. The difference in the apparent degree of natal homing behaviour among the different life-history stages of hawksbill turtles at Mona Island underscores the complexity of the species' life-history dynamics and highlights the need for both local and regional conservation efforts.

Monitoring persistent organic pollutants in leatherback turtles (Dermochelys coriacea) confirms maternal transfer.

PubMed

Stewart, Kelly R; Keller, Jennifer M; Templeton, Ryan; Kucklick, John R; Johnson, Chris

2011-07-01

To assess threats to endangered species, it is critical to establish baselines for contaminant concentrations that may have detrimental consequences to individuals or populations. We measured contaminants in blubber and fat from dead leatherback turtles and established baselines in blood and eggs in nesting turtles. In fat, blubber, blood and eggs, the predominant PCBs were 153+132, 187+182, 138+163, 118, and 180+193. Total PCBs, 4,4'-DDE, total PBDEs and total chlordanes were significantly and positively correlated between blood and eggs, suggesting maternal transfer. Significant positive relationships also existed between fat and blubber in stranded leatherbacks. Less lipophilic PCBs appeared to more readily transfer from females to their eggs. PBDE profiles in the four tissues were similar to other wildlife populations but different from some turtle studies. Concentrations were lower than those shown to have acute toxic effects in other aquatic reptiles, but may have sub-lethal effects on hatchling body condition and health. Copyright © 2011 Elsevier Ltd. All rights reserved.

Olive Ridley Sea Turtle Hatching Success as a Function of the Microbial Abundance in Nest Sand at Ostional, Costa Rica

PubMed Central

Bézy, Vanessa S.; Valverde, Roldán A.; Plante, Craig J.

2015-01-01

Several studies have suggested that significant embryo mortality is caused by microbes, while high microbial loads are generated by the decomposition of eggs broken by later nesting turtles. This occurs commonly when nesting density is high, especially during mass nesting events (arribadas). However, no previous research has directly quantified microbial abundance and the associated effects on sea turtle hatching success at a nesting beach. The aim of this study was to test the hypothesis that the microbial abundance in olive ridley sea turtle nest sand affects the hatching success at Ostional, Costa Rica. We applied experimental treatments to alter the microbial abundance within the sand into which nests were relocated. We monitored temperature, oxygen, and organic matter content throughout the incubation period and quantified the microbial abundance within the nest sand using a quantitative polymerase chain reaction (qPCR) molecular analysis. The most successful treatment in increasing hatching success was the removal and replacement of nest sand. We found a negative correlation between hatching success and fungal abundance (fungal 18S rRNA gene copies g-1 nest sand). Of secondary importance in determining hatching success was the abundance of bacteria (bacterial 16S rRNA gene copies g-1 g-1 nest sand). Our data are consistent with the hypothesis that high microbial activity is responsible for the lower hatching success observed at Ostional beach. Furthermore, the underlying mechanism appears to be the deprivation of oxygen and exposure to higher temperatures resulting from microbial decomposition in the nest. PMID:25714355

Natal foraging philopatry in eastern Pacific hawksbill turtles.

PubMed

Gaos, Alexander R; Lewison, Rebecca L; Jensen, Michael P; Liles, Michael J; Henriquez, Ana; Chavarria, Sofia; Pacheco, Carlos Mario; Valle, Melissa; Melero, David; Gadea, Velkiss; Altamirano, Eduardo; Torres, Perla; Vallejo, Felipe; Miranda, Cristina; LeMarie, Carolina; Lucero, Jesus; Oceguera, Karen; Chácon, Didiher; Fonseca, Luis; Abrego, Marino; Seminoff, Jeffrey A; Flores, Eric E; Llamas, Israel; Donadi, Rodrigo; Peña, Bernardo; Muñoz, Juan Pablo; Ruales, Daniela Alarcòn; Chaves, Jaime A; Otterstrom, Sarah; Zavala, Alan; Hart, Catherine E; Brittain, Rachel; Alfaro-Shigueto, Joanna; Mangel, Jeffrey; Yañez, Ingrid L; Dutton, Peter H

2017-08-01

The complex processes involved with animal migration have long been a subject of biological interest, and broad-scale movement patterns of many marine turtle populations still remain unresolved. While it is widely accepted that once marine turtles reach sexual maturity they home to natal areas for nesting or reproduction, the role of philopatry to natal areas during other life stages has received less scrutiny, despite widespread evidence across the taxa. Here we report on genetic research that indicates that juvenile hawksbill turtles ( Eretmochelys imbricata ) in the eastern Pacific Ocean use foraging grounds in the region of their natal beaches, a pattern we term natal foraging philopatry. Our findings confirm that traditional views of natal homing solely for reproduction are incomplete and that many marine turtle species exhibit philopatry to natal areas to forage. Our results have important implications for life-history research and conservation of marine turtles and may extend to other wide-ranging marine vertebrates that demonstrate natal philopatry.

Natal foraging philopatry in eastern Pacific hawksbill turtles

PubMed Central

Lewison, Rebecca L.; Jensen, Michael P.; Liles, Michael J.; Henriquez, Ana; Chavarria, Sofia; Pacheco, Carlos Mario; Valle, Melissa; Melero, David; Gadea, Velkiss; Altamirano, Eduardo; Torres, Perla; Vallejo, Felipe; Miranda, Cristina; LeMarie, Carolina; Lucero, Jesus; Oceguera, Karen; Chácon, Didiher; Fonseca, Luis; Abrego, Marino; Seminoff, Jeffrey A.; Flores, Eric E.; Llamas, Israel; Donadi, Rodrigo; Peña, Bernardo; Muñoz, Juan Pablo; Ruales, Daniela Alarcòn; Chaves, Jaime A.; Otterstrom, Sarah; Zavala, Alan; Hart, Catherine E.; Brittain, Rachel; Alfaro-Shigueto, Joanna; Mangel, Jeffrey; Yañez, Ingrid L.; Dutton, Peter H.

2017-01-01

The complex processes involved with animal migration have long been a subject of biological interest, and broad-scale movement patterns of many marine turtle populations still remain unresolved. While it is widely accepted that once marine turtles reach sexual maturity they home to natal areas for nesting or reproduction, the role of philopatry to natal areas during other life stages has received less scrutiny, despite widespread evidence across the taxa. Here we report on genetic research that indicates that juvenile hawksbill turtles (Eretmochelys imbricata) in the eastern Pacific Ocean use foraging grounds in the region of their natal beaches, a pattern we term natal foraging philopatry. Our findings confirm that traditional views of natal homing solely for reproduction are incomplete and that many marine turtle species exhibit philopatry to natal areas to forage. Our results have important implications for life-history research and conservation of marine turtles and may extend to other wide-ranging marine vertebrates that demonstrate natal philopatry. PMID:28878969

Population structure and the evolution of sexual size dimorphism and sex ratios in an insular population of Florida box turtles (Terrapene carolina bauri)

USGS Publications Warehouse

Dodd, C.K.

1997-01-01

Hypotheses in the chelonian literature suggest that in species with sexual size dimorphism, the smaller sex will mature at a smaller size and a younger age than the larger sex, sex ratios should be biased in favor of the earlier maturing sex, and deviations from a 1:1 sex ratio result from maturation of the smaller sex at a younger age. I tested these hypotheses using data collected from 1991 to 1995 on an insular (Egmont Key) population of Florida box turtles, Terrapene carolina bauri. Contrary to predictions, the earlier maturing sex (males) grew to larger sizes than the late maturing sex. Males were significantly larger than females in mean carapace length but not mean body mass. Sex ratios were not balanced, favoring the earlier maturing sex (1.6 males:1 female), but the sex-ratio imbalance did not result from faster maturation of the smaller sex. The imbalance in the sex ratio in Egmont Key's box turtles is not the result of sampling biases; it may result from nest placement. Size-class structure and sex ratios can provide valuable insights into the status and trends of populations of long-lived turtles.

Age and season impact resource allocation to eggs and nesting behavior in the painted turtle.

PubMed

Harms, Heidi K; Paitz, Ryan T; Bowden, Rachel M; Janzen, Fredric J

2005-01-01

Theory predicts that in long-lived organisms females should invest less energy in reproduction and more in growth and self-maintenance early in life, with this balance shifting as females age and the relative value of each reproductive event increases. We investigated this potential trade-off by characterizing within-population variation in resource allocation to eggs by female painted turtles (Chrysemys picta) and relating this variation to their nesting ecology and life history. We examined lipid and protein allocation to yolks, accounting for both relative female age and seasonal effects (first vs. second clutches within a female). Older females appear to increase their investment in reproduction by producing larger eggs, but these eggs are not disproportionately more lipid or protein rich than the smaller eggs from younger females. Within the nesting season, first clutches have more lipid and protein than second clutches. We also found that younger females nest closer to the water than older females. Our results indicate that trade-offs involving resource allocation and nesting behavior do occur both seasonally and with age, suggesting ontogenetic variation in life-history strategies in this long-lived organism.

Microplastic at nesting grounds used by the northern Gulf of Mexico loggerhead recovery unit.

PubMed

Beckwith, Valencia K; Fuentes, Mariana M P B

2018-06-01

Microplastics can impact key habitats used by endangered species, such as marine turtles. They impact the environment by transporting toxicants and altering sediment properties affecting temperature and sediment permeability. Our study determined the exposure of the ten most important nesting sites for the Northern Gulf of Mexico Loggerhead Recovery Unit to microplastic. Sand samples were obtained at each nesting site during the 2017 nesting season and analyzed for abundance and characteristics of microplastic. Microplastic was found at all sites, with an average abundance of 61.08 ± 34.61 pieces/m 2 , and 59.9% located at the dunes, where turtles primarily nest. A gradual decrease in microplastics abundance was observed from the most western nesting ground to the east. The results from this study indicate that microplastic accumulation on nesting sites for the Northern Gulf of Mexico may be of great concern, and could negatively affect the incubating environment for marine turtles. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stream and riparian management for freshwater turtles.

PubMed

Bodie, J R

2001-08-01

The regulation and management of stream ecosystems worldwide have led to irreversible loss of wildlife species. Due to recent scrutiny of water policy and dam feasibility, there is an urgent need for fundamental research on the biotic integrity of streams and riparian zones. Although riverine turtles rely on stream and riparian zones to complete their life cycle, are vital producers and consumers, and are declining worldwide, they have received relatively little attention. I review the literature on the impacts of contemporary stream management on freshwater turtles. Specifically, I summarize and discuss 10 distinct practices that produce five potential biological repercussions. I then focus on the often-overlooked use of riparian zones by freshwater turtles, calculate a biologically determined riparian width, and offer recommendations for ecosystem management. Migration data were summarized on 10 species from eight US states and four countries. A riparian zone encompassing the majority of freshwater turtle migrations would need to span 150 m from the stream edge. Freshwater turtles primarily chose high, open sandy habitats to nest. Nests in North America contained eggs and hatchlings during April through September and often through the winter. In addition, freshwater turtles utilized diverse riparian habitats for feeding, nesting, and overwintering. Additional documentation of stream and riparian habitat use by turtles is needed.

Seasonal changes in serum gonadal steroids associated with migration, mating, and nesting in the loggerhead sea turtle (Caretta caretta).

PubMed

Wibbels, T; Owens, D W; Limpus, C J; Reed, P C; Amoss, M S

1990-07-01

Adult male loggerhead sea turtles, Caretta caretta, exhibited a "prenuptial" spermatogenic cycle that was coincident with increased concentrations of serum testosterone (T). Serum T was high during the months when migration and mating have been recorded for males. In contrast to females, males appear to be annual breeders. Nine reproductively active female C. caretta (as verified through laparoscopy) were tagged with sonic transmitters and were repeatedly bled prior to migration. Four months prior to the nesting season, the ovaries of reproductively active females had hundreds of vitellogenic follicles of approximately 1.5 cm in diameter (i.e., half the size of ovulatory follicles). Approximately 4-6 weeks prior to migration from feeding grounds to mating and nesting areas, serum estradiol-17 beta (E2) concentrations increased significantly and remained high for approximately 4 weeks, suggesting a period of increased vitellogenesis. During a 1- to 2-week period prior to migration, serum E2 decreased significantly, while serum T concentrations increased (at least) until the time of migration. Serum T, E2, and progesterone (PRO) were elevated during nesting if a turtle was going to nest again during that nesting season. During the last nesting of a season, turtles had low serum concentrations of T, E2, and Pro. The prenuptial pattern of gonadal recrudescence and gonadal steroid production in both male and female C. caretta contrasts with those of many temperate freshwater turtles, and this type of reproductive pattern may have been facilitated by adaptation to a tropical marine environment.

Beach dynamics and nest distribution of the leatherback turtle (Dermochelys coriacea) at Grande Riviere Beach, Trinidad & Tobago.

PubMed

Lum, Lori Lee

2005-05-01

Grande Riviere Beach in Trinidad and Tobago is an important nesting site in the Caribbean for the Critically Endangered leatherback sea turtle, Dermochelys coriacea. Community members were concerned that beach erosion and seasonal river flooding were destroying many of the nests deposited annually and thought that a hatchery was a possible solution. Over the 2001 turtle nesting season, the Institute of Marine Affairs (IMA) assessed the spatial and temporal distribution of nests using the Global Positioning System recorded to reference points, and beach dynamics using permanent bench mark profile stations, to determine areas of high risk and more stable areas for nesting. A total of 1449 leatherback nests were positioned. It was evident that at the start of the season in March, the majority of leatherback nests were deposited at the eastern section of the beach. After May, there was a continuing westward shift in nest distribution as the season progressed until August and beach erosion in the eastern section became predominant. The backshore remained relatively stable along the entire beach throughout the nesting season, and erosion was predominant in the foreshore at the eastern section of the beach, from the middle to the end of the season. Similar trends in accretion and erosion were observed in 2000. River flooding did not occur during the study period or in the previous year. With both high risk and more stable regions for turtle nesting available at Grande Riviere Beach, there was no compelling evidence to justify the need for a hatchery.

The Maternal Legacy: Female Identity Predicts Offspring Sex Ratio in the Loggerhead Sea Turtle.

PubMed

Reneker, Jaymie L; Kamel, Stephanie J

2016-07-01

In organisms with temperature-dependent sex determination, the incubation environment plays a key role in determining offspring sex ratios. Given that global temperatures have warmed approximately 0.6 °C in the last century, it is necessary to consider how organisms will adjust to climate change. To better understand the degree to which mothers influence the sex ratios of their offspring, we use 24 years of nesting data for individual female loggerhead sea turtles (Caretta caretta) observed on Bald Head Island, North Carolina. We find that maternal identity is the best predictor of nest sex ratio in univariate and multivariate predictive models. We find significant variability in estimated nest sex ratios among mothers, but a high degree of consistency within mothers, despite substantial spatial and temporal thermal variation. Our results suggest that individual differences in nesting preferences are the main driver behind divergences in nest sex ratios. As such, a female's ability to plastically adjust her nest sex ratios in response to environmental conditions is constrained, potentially limiting how individuals behaviorally mitigate the effects of environmental change. Given that many loggerhead populations already show female-biased offspring sex ratios, understanding maternal behavioral responses is critical for predicting the future of long-lived species vulnerable to extinction.

The Maternal Legacy: Female Identity Predicts Offspring Sex Ratio in the Loggerhead Sea Turtle

PubMed Central

Reneker, Jaymie L.; Kamel, Stephanie J.

2016-01-01

In organisms with temperature-dependent sex determination, the incubation environment plays a key role in determining offspring sex ratios. Given that global temperatures have warmed approximately 0.6 °C in the last century, it is necessary to consider how organisms will adjust to climate change. To better understand the degree to which mothers influence the sex ratios of their offspring, we use 24 years of nesting data for individual female loggerhead sea turtles (Caretta caretta) observed on Bald Head Island, North Carolina. We find that maternal identity is the best predictor of nest sex ratio in univariate and multivariate predictive models. We find significant variability in estimated nest sex ratios among mothers, but a high degree of consistency within mothers, despite substantial spatial and temporal thermal variation. Our results suggest that individual differences in nesting preferences are the main driver behind divergences in nest sex ratios. As such, a female’s ability to plastically adjust her nest sex ratios in response to environmental conditions is constrained, potentially limiting how individuals behaviorally mitigate the effects of environmental change. Given that many loggerhead populations already show female-biased offspring sex ratios, understanding maternal behavioral responses is critical for predicting the future of long-lived species vulnerable to extinction. PMID:27363786

Determining origin in a migratory marine vertebrate: a novel method to integrate stable isotopes and satellite tracking

USGS Publications Warehouse

Vander Zanden, Hannah B.; Tucker, Anton D.; Hart, Kristen M.; Lamont, Margaret M.; Fujisaki, Ikuko; Addison, David S.; Mansfield, Katherine L.; Phillips, Katrina F.; Wunder, Michael B.; Bowen, Gabriel J.; Pajuelo, Mariela; Bolten, Alan B.; Bjorndal, Karen A.

2015-01-01

Stable isotope analysis is a useful tool to track animal movements in both terrestrial and marine environments. These intrinsic markers are assimilated through the diet and may exhibit spatial gradients as a result of biogeochemical processes at the base of the food web. In the marine environment, maps to predict the spatial distribution of stable isotopes are limited, and thus determining geographic origin has been reliant upon integrating satellite telemetry and stable isotope data. Migratory sea turtles regularly move between foraging and reproductive areas. Whereas most nesting populations can be easily accessed and regularly monitored, little is known about the demographic trends in foraging populations. The purpose of the present study was to examine migration patterns of loggerhead nesting aggregations in the Gulf of Mexico (GoM), where sea turtles have been historically understudied. Two methods of geographic assignment using stable isotope values in known-origin samples from satellite telemetry were compared: 1) a nominal approach through discriminant analysis and 2) a novel continuous-surface approach using bivariate carbon and nitrogen isoscapes (isotopic landscapes) developed for this study. Tissue samples for stable isotope analysis were obtained from 60 satellite-tracked individuals at five nesting beaches within the GoM. Both methodological approaches for assignment resulted in high accuracy of foraging area determination, though each has advantages and disadvantages. The nominal approach is more appropriate when defined boundaries are necessary, but up to 42% of the individuals could not be considered in this approach. All individuals can be included in the continuous-surface approach, and individual results can be aggregated to identify geographic hotspots of foraging area use, though the accuracy rate was lower than nominal assignment. The methodological validation provides a foundation for future sea turtle studies in the region to inexpensively determine geographic origin for large numbers of untracked individuals. Regular monitoring of sea turtle nesting aggregations with stable isotope sampling can be used to fill critical data gaps regarding habitat use and migration patterns. Probabilistic assignment to origin with isoscapes has not been previously used in the marine environment, but the methods presented here could also be applied to other migratory marine species.

Determining origin in a migratory marine vertebrate: a novel method to integrate stable isotopes and satellite tracking.

PubMed

Zanden, Hannah B Vander; Tucker, Anton D; Hart, Kristen M; Lamont, Margaret M; Fuisaki, Ikuko; Addison, David; Mansfield, Katherine L; Phillips, Katrina F; Wunder, Michael B; Bowen, Gabriel J; Pajuelo, Mariela; Bolten, Alan B; Bjorndal, Karen A

2015-03-01

Stable isotope analysis is a useful tool to track animal movements in both terrestrial and marine environments. These intrinsic markers are assimilated through the diet and may exhibit spatial gradients as a result of biogeochemical processes at the base of the food web. In the marine environment, maps to predict the spatial distribution of stable isotopes are limited, and thus determining geographic origin has been reliant upon integrating satellite telemetry and stable isotope data. Migratory sea turtles regularly move between foraging and reproductive areas. Whereas most nesting populations can be easily accessed and regularly monitored, little is known about the demographic trends in foraging populations. The purpose of the present study was to examine migration patterns of loggerhead nesting aggregations in the Gulf of Mexico (GoM), where sea turtles have been historically understudied. Two methods of geographic assignment using stable isotope values in known-origin samples from satellite telemetry were compared: (1) a nominal approach through discriminant analysis and (2) a novel continuous-surface approach using bivariate carbon and nitrogen isoscapes (isotopic landscapes) developed for this study. Tissue samples for stable isotope analysis were obtained from 60 satellite-tracked individuals at five nesting beaches within the GoM. Both methodological approaches for assignment resulted in high accuracy of foraging area determination, though each has advantages and disadvantages. The nominal approach is more appropriate when defined boundaries are necessary, but up to 42% of the individuals could not be considered in this approach. All individuals can be included in the continuous-surface approach, and individual results can be aggregated to identify geographic hotspots of foraging area use, though the accuracy rate was lower than nominal assignment. The methodological validation provides a foundation for future sea turtle studies in the region to inexpensively determine geographic origin for large numbers of untracked individuals. Regular monitoring of sea turtle nesting aggregations with stable isotope sampling can be used to fill critical data gaps regarding habitat use and migration patterns. Probabilistic assignment to origin with isoscapes has not been previously used in the marine environment, but the methods presented here could also be applied to other migratory marine species.

Spatio-temporal variation in the incubation duration and sex ratio of hawksbill hatchlings: implication for future management.

PubMed

dei Marcovaldi, Maria A G; Santos, Armando J B; Santos, Alexsandro S; Soares, Luciano S; Lopez, Gustave G; Godfrey, Matthew H; López-Mendilaharsu, Milagros; Fuentes, Mariana M P B

2014-08-01

Climate change poses a unique threat to species with temperature dependent sex determination (TSD), such as marine turtles, where increases in temperature can result in extreme sex ratio biases. Knowledge of the primary sex ratio of populations with TSD is key for providing a baseline to inform management strategies and to accurately predict how future climate changes may affect turtle populations. However, there is a lack of robust data on offspring sex ratio at appropriate temporal and spatial scales to inform management decisions. To address this, we estimate the primary sex ratio of hawksbill hatchlings, Eretmochelys imbricata, from incubation duration of 5514 in situ nests from 10 nesting beaches from two regions in Brazil over the last 27 years. A strong female bias was estimated in all beaches, with 96% and 89% average female sex ratios produced in Bahia (BA) and Rio Grande do Norte (RN). Both inter-annual (BA, 88 to 99%; RN, 75 to 96% female) and inter-beach (BA, 92% to 97%; RN, 81% to 92% female) variability in mean offspring sex ratio was observed. These findings will guide management decisions in Brazil and provide further evidence of highly female-skew sex ratios in hawksbill turtles. Copyright © 2014 Elsevier Ltd. All rights reserved.

First fossil gravid turtle provides insight into the evolution of reproductive traits in turtles.

PubMed

Zelenitsky, Darla K; Therrien, Franc Ois; Joyce, Walter G; Brinkman, Donald B

2008-12-23

Here we report on the first discovery of shelled eggs inside the body cavity of a fossil turtle and on an isolated egg clutch, both referable to the Cretaceous turtle Adocus. These discoveries provide a unique opportunity to gain insight into the reproductive traits of an extinct turtle and to understand the evolution of such traits among living turtles. The gravid adult and egg clutch indicate that Adocus laid large clutches of rigid-shelled spherical eggs and established their nests near rivers, traits that are shared by its closest living relatives, the soft-shelled turtles. Adocus eggshell, however, was probably more rigid than that of living turtles, based on its great thickness and structure, features that may represent unique adaptations to intense predation or to arid nest environments. In light of the reproductive traits observed in Adocus, the distribution of reproductive traits among turtles reveals that large clutches of rigid-shelled eggs are primitive for hidden-necked turtles (cryptodirans) and that spherical eggs may have evolved independently within this group.

Ghrelin and leptin modulate the feeding behaviour of the hawksbill turtle Eretmochelys imbricata during nesting season

PubMed Central

Goldberg, Daphne Wrobel; Leitão, Santiago Alonso Tobar; Godfrey, Matthew H.; Lopez, Gustave Gilles; Santos, Armando José Barsante; Neves, Fabiana Alves; de Souza, Érica Patrícia Garcia; Moura, Anibal Sanchez; Bastos, Jayme da Cunha; Bastos, Vera Lúcia Freire da Cunha

2013-01-01

Female sea turtles have rarely been observed foraging during the nesting season. This suggests that prior to their migration to nesting beaches the females must store sufficient energy and nutrients at their foraging grounds and must be physiologically capable of undergoing months without feeding. Leptin (an appetite-suppressing protein) and ghrelin (a hunger-stimulating peptide) affect body weight by influencing energy intake in all vertebrates. We investigated the levels of these hormones and other physiological and nutritional parameters in nesting hawksbill sea turtles in Rio Grande do Norte State, Brazil, by collecting consecutive blood samples from 41 turtles during the 2010–2011 and 2011–2012 reproductive seasons. We found that levels of serum leptin decreased over the nesting season, which potentially relaxed suppression of food intake and stimulated females to begin foraging either during or after the post-nesting migration. Concurrently, we recorded an increasing trend in ghrelin, which may have stimulated food intake towards the end of the nesting season. Both findings are consistent with the prediction that post-nesting females will begin to forage, either during or immediately after their post-nesting migration. We observed no seasonal trend for other physiological parameters (values of packed cell volume and serum levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, γ-glutamyl transferase, low-density lipoprotein, and high-density lipoprotein). The observed downward trends in general serum biochemistry levels were probably due to the physiological challenge of vitellogenesis and nesting in addition to limited energy resources and probable fasting. PMID:27293600

Extreme developmental temperatures result in morphological abnormalities in painted turtles (Chrysemys picta): a climate change perspective.

PubMed

Telemeco, Rory S; Warner, Daniel A; Reida, Molly K; Janzen, Fredric J

2013-06-01

Increases in extreme environmental events are predicted to be major results of ongoing global climate change and may impact the persistence of species. We examined the effects of heat and cold waves during embryonic development of painted turtles (Chrysemys picta) in natural nests on the occurrence of abnormal shell morphologies in hatchlings. We found that nests exposed to extreme hot temperatures for >60 h produced more hatchlings with abnormalities than nests exposed to extreme hot temperatures for shorter periods, regardless of whether or not nesting females displayed abnormal morphologies. We observed no effect of extreme cold nest temperatures on the occurrence of hatchlings with abnormalities. Moreover, the frequency of nesting females with abnormal shell morphologies was approximately 2-fold lower than that of their offspring, suggesting that such abnormalities are negatively correlated with survival and fitness. Female turtles could potentially buffer their offspring from extreme heat by altering aspects of nesting behavior, such as choosing shadier nesting sites. We addressed this hypothesis by examining the effects of shade cover on extreme nest temperatures and the occurrence of hatchling abnormalities. While shade cover was negatively correlated with the occurrence of extreme hot nest temperatures, it was not significantly correlated with abnormalities. Therefore, female choice of shade cover does not appear to be a viable target for selection to reduce hatchling abnormalities. Our results suggest that increases in the frequency and intensity of heat waves associated with climate change might perturb developmental programs and thereby reduce the fitness of entire cohorts of turtles. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

Ghrelin and leptin modulate the feeding behaviour of the hawksbill turtle Eretmochelys imbricata during nesting season.

PubMed

Goldberg, Daphne Wrobel; Leitão, Santiago Alonso Tobar; Godfrey, Matthew H; Lopez, Gustave Gilles; Santos, Armando José Barsante; Neves, Fabiana Alves; de Souza, Érica Patrícia Garcia; Moura, Anibal Sanchez; Bastos, Jayme da Cunha; Bastos, Vera Lúcia Freire da Cunha

2013-01-01

Female sea turtles have rarely been observed foraging during the nesting season. This suggests that prior to their migration to nesting beaches the females must store sufficient energy and nutrients at their foraging grounds and must be physiologically capable of undergoing months without feeding. Leptin (an appetite-suppressing protein) and ghrelin (a hunger-stimulating peptide) affect body weight by influencing energy intake in all vertebrates. We investigated the levels of these hormones and other physiological and nutritional parameters in nesting hawksbill sea turtles in Rio Grande do Norte State, Brazil, by collecting consecutive blood samples from 41 turtles during the 2010-2011 and 2011-2012 reproductive seasons. We found that levels of serum leptin decreased over the nesting season, which potentially relaxed suppression of food intake and stimulated females to begin foraging either during or after the post-nesting migration. Concurrently, we recorded an increasing trend in ghrelin, which may have stimulated food intake towards the end of the nesting season. Both findings are consistent with the prediction that post-nesting females will begin to forage, either during or immediately after their post-nesting migration. We observed no seasonal trend for other physiological parameters (values of packed cell volume and serum levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, γ-glutamyl transferase, low-density lipoprotein, and high-density lipoprotein). The observed downward trends in general serum biochemistry levels were probably due to the physiological challenge of vitellogenesis and nesting in addition to limited energy resources and probable fasting.

Deepwater Horizon oil spill impacts on sea turtles could span the Atlantic.

PubMed

Putman, Nathan F; Abreu-Grobois, F Alberto; Iturbe-Darkistade, Iñaky; Putman, Emily M; Richards, Paul M; Verley, Philippe

2015-12-01

We investigated the extent that the 2010 Deepwater Horizon oil spill potentially affected oceanic-stage sea turtles from populations across the Atlantic. Within an ocean-circulation model, particles were backtracked from the Gulf of Mexico spill site to determine the probability of young turtles arriving in this area from major nesting beaches. The abundance of turtles in the vicinity of the oil spill was derived by forward-tracking particles from focal beaches and integrating population size, oceanic-stage duration and stage-specific survival rates. Simulations indicated that 321 401 (66 199-397 864) green (Chelonia mydas), loggerhead (Caretta caretta) and Kemp's ridley (Lepidochelys kempii) turtles were likely within the spill site. These predictions compared favourably with estimates from in-water observations recently made available to the public (though our initial predictions for Kemp's ridley were substantially lower than in-water estimates, better agreement was obtained with modifications to mimic behaviour of young Kemp's ridley turtles in the northern Gulf). Simulations predicted 75.2% (71.9-76.3%) of turtles came from Mexico, 14.8% (11-18%) from Costa Rica, 5.9% (4.8-7.9%) from countries in northern South America, 3.4% (2.4-3.5%) from the United States and 1.6% (0.6-2.0%) from West African countries. Thus, the spill's impacts may extend far beyond the current focus on the northern Gulf of Mexico. © 2015 The Authors.

Marine tourism and the locations of protected turtles on Sukamade Beach, Meru Betiri National Park, East Java

NASA Astrophysics Data System (ADS)

Prihadi, D. J.; Shofiyullah, A.; Dhahiyat, Y.

2018-04-01

The research was conducted in Sukamade Beach, Meru Betiri National Park, East Java. The purpose of this research was to identify marine tourism activity and to determine the differences in the characteristics of turtle-nesting beaches towards the number and species of turtles that came to the beach. Data collection conducted in August-September 2014. The method used in this research was a survey method at 7 reseach stations to collect primary data (biophysical characteristics) and secondary data. The Primary data was collected by monitoring turtles, width and slope of the beach, temperature, pH, moisture, sand texture, and beach vegetation conditions at each station. The results of the research shows that marine tourisms always involve tourists who attend to see turtle nesting, when turtles arrive at the beach, and turtles return to the sea, how large the turtles and how they lay eggs on the beach, and the release of little turtles (tukik). The number of turtles that landed from station 1 to station 7 is as many as 311 individuals of three species. The most dominant species of turtles that arrived at the beach is green turtle (Chelonia mydas), followed by olive ridley turtles (Lepidochelys olivaceae) and leatherbacks turtles (Dermochelys coriacea).

Sources of Vibrio mimicus Contamination of Turtle Eggs

PubMed Central

Acuña, María T.; Díaz, Gerardo; Bolaños, Hilda; Barquero, Candy; Sánchez, Olga; Sánchez, Luz M.; Mora, Grettel; Chaves, Anny; Campos, Elena

1999-01-01

Vibrio mimicus contamination of sand increased significantly during the arrival of the olive ridley sea turtles (Lepidochelys olivacea) at Ostional anidation beach, Costa Rica. Statistical analysis supports that eggs are contaminated with V. mimicus by contact with the sand nest. V. mimicus was isolated from eggs of all nests tested, and ctxA+ strains were found in 31% of the nests, all of which were near the estuary. PMID:9872804

Inter-nesting movements and habitat-use of adult female Kemp’s ridley turtles in the Gulf of Mexico

PubMed Central

Hart, Kristen M.; Fujisaki, Ikuko; Bucklin, David; Iverson, Autumn R.; Rubio, Cynthia; Backof, Thomas F.; Burchfield, Patrick M.; de Jesus Gonzales Diaz Miron, Raul; Dutton, Peter H.; Frey, Amy; Peña, Jaime; Gomez Gamez, Daniel; Martinez, Hector J.; Ortiz, Jaime

2017-01-01

Species vulnerability is increased when individuals congregate in restricted areas for breeding; yet, breeding habitats are not well defined for many marine species. Identification and quantification of these breeding habitats are essential to effective conservation. Satellite telemetry and switching state-space modeling (SSM) were used to define inter-nesting habitat of endangered Kemp’s ridley turtles (Lepidochelys kempii) in the Gulf of Mexico. Turtles were outfitted with satellite transmitters after nesting at Padre Island National Seashore, Texas, USA, from 1998 through 2013 (n = 60); Rancho Nuevo, Tamaulipas, Mexico, during 2010 and 2011 (n = 11); and Tecolutla, Veracruz, Mexico, during 2012 and 2013 (n = 11). These sites span the range of nearly all nesting by this species. Inter-nesting habitat lies in a narrow band of nearshore western Gulf of Mexico waters in the USA and Mexico, with mean water depth of 14 to 19 m within a mean distance to shore of 6 to 11 km as estimated by 50% kernel density estimate, α-Hull, and minimum convex polygon methodologies. Turtles tracked during the inter-nesting period moved, on average, 17.5 km/day and a mean total distance of 398 km. Mean home ranges occupied were 725 to 2948 km2. Our results indicate that these nearshore western Gulf waters represent critical inter-nesting habitat for this species, where threats such as shrimp trawling and oil and gas platforms also occur. Up to half of all adult female Kemp’s ridleys occupy this habitat for weeks to months during each nesting season. Because inter-nesting habitat for this species is concentrated in nearshore waters of the western Gulf of Mexico in both Mexico and the USA, international collaboration is needed to protect this essential habitat and the turtles occurring within it. PMID:28319178

A risk assessment approach to manage inundation of Elseya albagula nests in impounded waters: a win-win situation?

PubMed

McDougall, A J; Espinoza, T; Hollier, C; Limpus, D J; Limpus, C J

2015-03-01

A risk assessment process was used to trial the impact of potential new operating rules on the frequency of nest inundation for the White-throated snapping turtle, Elseya albagula, in the impounded waters of the Burnett River, Queensland, Australia. The proposed operating rules would increase the barrage storage level during the turtle nesting season (May-July) and then would be allowed to reduce to a lower level for incubation for the rest of the year. These proposed operating rules reduce rates of nest inundation by altering water levels in the Ben Anderson Barrage impoundment of the Burnett River. The rules operate throughout the turtle reproductive period and concomitantly improve stability of littoral habitat and fishway operation. Additionally, the proposed rules are expected to have positive socio-economic benefits within the region. While regulated water resources will inherently have a number of negative environmental implications, these potential new operating rules have the capacity to benefit the environment while managing resources in a more sustainable manner. The operating rules have now been enacted in subordinate legislation and require the operator to maintain water levels to minimize turtle nest inundation.

A Risk Assessment Approach to Manage Inundation of Elseya albagula Nests in Impounded Waters: A Win-Win Situation?

NASA Astrophysics Data System (ADS)

McDougall, A. J.; Espinoza, T.; Hollier, C.; Limpus, D. J.; Limpus, C. J.

2015-03-01

A risk assessment process was used to trial the impact of potential new operating rules on the frequency of nest inundation for the White-throated snapping turtle, Elseya albagula, in the impounded waters of the Burnett River, Queensland, Australia. The proposed operating rules would increase the barrage storage level during the turtle nesting season (May-July) and then would be allowed to reduce to a lower level for incubation for the rest of the year. These proposed operating rules reduce rates of nest inundation by altering water levels in the Ben Anderson Barrage impoundment of the Burnett River. The rules operate throughout the turtle reproductive period and concomitantly improve stability of littoral habitat and fishway operation. Additionally, the proposed rules are expected to have positive socio-economic benefits within the region. While regulated water resources will inherently have a number of negative environmental implications, these potential new operating rules have the capacity to benefit the environment while managing resources in a more sustainable manner. The operating rules have now been enacted in subordinate legislation and require the operator to maintain water levels to minimize turtle nest inundation.

Predicting species interactions from edge responses: mongoose predation on hawksbill sea turtle nests in fragmented beach habitat.

PubMed

Leighton, Patrick A; Horrocks, Julia A; Krueger, Barry H; Beggs, Jennifer A; Kramer, Donald L

2008-11-07

Because species respond differently to habitat boundaries and spatial overlap affects encounter rates, edge responses should be strong determinants of spatial patterns of species interactions. In the Caribbean, mongooses (Herpestes javanicus) prey on hawksbill sea turtle (Eretmochelys imbricata) eggs. Turtles nest in both open sand and vegetation patches, with a peak in nest abundance near the boundary between the two microhabitats; mongooses rarely leave vegetation. Using both artificial nests and hawksbill nesting data, we examined how the edge responses of these species predict the spatial patterns of nest mortality. Predation risk was strongly related to mongoose abundance but was not affected by nest density or habitat type. The product of predator and prey edge response functions accurately described the observed pattern of total prey mortality. Hawksbill preference for vegetation edge becomes an ecological trap in the presence of mongooses. This is the first study to predict patterns of predation directly from continuous edge response functions of interacting species, establishing a link between models of edge response and species interactions.

Predicting species interactions from edge responses: mongoose predation on hawksbill sea turtle nests in fragmented beach habitat

PubMed Central

Leighton, Patrick A; Horrocks, Julia A; Krueger, Barry H; Beggs, Jennifer A; Kramer, Donald L

2008-01-01

Because species respond differently to habitat boundaries and spatial overlap affects encounter rates, edge responses should be strong determinants of spatial patterns of species interactions. In the Caribbean, mongooses (Herpestes javanicus) prey on hawksbill sea turtle (Eretmochelys imbricata) eggs. Turtles nest in both open sand and vegetation patches, with a peak in nest abundance near the boundary between the two microhabitats; mongooses rarely leave vegetation. Using both artificial nests and hawksbill nesting data, we examined how the edge responses of these species predict the spatial patterns of nest mortality. Predation risk was strongly related to mongoose abundance but was not affected by nest density or habitat type. The product of predator and prey edge response functions accurately described the observed pattern of total prey mortality. Hawksbill preference for vegetation edge becomes an ecological trap in the presence of mongooses. This is the first study to predict patterns of predation directly from continuous edge response functions of interacting species, establishing a link between models of edge response and species interactions. PMID:18647718

The ecology of overwintering among turtles: where turtles overwinter and its consequences.

PubMed

Ultsch, Gordon R

2006-08-01

Turtles are a small taxon that has nevertheless attracted much attention from biologists for centuries. However, a major portion of their life cycle has received relatively little attention until recently - namely what turtles are doing, and how they are doing it, during the winter. In the northern parts of their ranges in North America, turtles may spend more than half of their lives in an overwintering state. In this review, I emphasise the ecological aspects of overwintering among turtles, and consider how overwintering stresses affect the physiology, behaviour, distributions, and life histories of various species. Sea turtles are the only group of turtles that migrate extensively, and can therefore avoid northern winters. Nevertheless, each year a number of turtles, largely juveniles, are killed when trapped by cold fronts before they move to safer waters. Evidently this risk is an acceptable trade-off for the benefits to a population of inhabiting northern developmental habitats during the summer. Terrestrial turtles pass the winter underground, either in burrows that they excavate or that are preformed. These refugia must provide protection against desiccation and lethal freezing levels. Some burrows are extensive (tortoise genus Gopherus), while others are shallow, or the turtles may simply dig into the ground to a safe depth (turtle genus Terrapene). In the latter genus, freeze tolerance may play an adaptive role. Most non-marine aquatic turtles overwinter underwater, although Clemmys (Actinemys) marmorata routinely overwinters on land when it occurs in riverine habitats, Kinosternon subrubrum often overwinters on land, and several others may overwinter terrestrially on occasion, especially in more southern climates. For northern species that overwinter underwater, there are two physiological groupings, those that are anoxia-tolerant and those that are relatively anoxia-intolerant. All species fare well physiologically in water with a high partial pressure of oxygen (PO2). A lack of anoxia tolerance limits the types of habitats that a freshwater turtle may live in, since unlike sea turtles, they cannot travel long distances to hibernate. Hatchlings of some species of turtles spend their first winter in or below the nest cavity, while hatchlings of other species in the same area, including northern areas, emerge in the autumn and presumably hibernate underwater. All hatchlings are relatively anoxia-intolerant, and there are no studies to date of where hatchling turtles that do not overwinter in or below the nest cavity spend their first winter. Equally little is known of the ontogeny of anoxia tolerance, other than that adults of all species are more anoxia-tolerant than their hatchlings, probably because of their better ossified shells, which provide adults with more buffer reserves and a larger site in which to sequester lactate. The northern limits of turtles are most likely determined by reproductive limitations (time for egg-laying, incubation, and hatching) than by the rigors of hibernation. Mortality is typically lower in turtle populations during hibernation than it is during their active periods. However, episodic mortality events do occur during hibernation, due to freezing, prolonged anoxia, or predation.

Loggerhead sea turtle environmental sex determination: implications of moisture and temperature for climate change based predictions for species survival.

PubMed

Wyneken, Jeanette; Lolavar, Alexandra

2015-05-01

It has been proposed that because marine turtles have environmentally determined sex by incubation temperature, elevated temperatures might skew sex ratios to unsustainable levels, leading to extinction. Elevated temperatures may also reduce availability of suitable nesting sites via sea level rise. Increased tropical storm activity can directly affect nest site moisture, embryonic development, and the probability that nests will survive. Here, we question some of these assumptions and review the limits of sex ratio estimates. Sea turtles may be more resilient to climate change than previously thought, in part because of hitherto unappreciated mechanisms for coping with variable incubation conditions. © 2015 Wiley Periodicals, Inc.

Beach Geomorphology and Kemp's Ridley (Lepidochelys kempii) Nest Site Selection along Padre Island, Texas, USA

NASA Astrophysics Data System (ADS)

Culver, M.; Gibeaut, J. C.; Shaver, D. J.; Tissot, P.; Starek, M. J.

2017-12-01

The Kemp's ridley sea turtle (Lepidochelys kempii) is the most endangered sea turtle in the world, largely due to the limited geographic range of its nesting habitat. In the U.S., the majority of nesting occurs along Padre Island National Seashore (PAIS) in Texas. There has been limited research regarding the connection between beach geomorphology and Kemp's ridley nesting patterns, but studies concerning other sea turtle species suggest that certain beach geomorphology variables, such as beach slope and width, influence nest site selection. This research investigates terrestrial habitat variability of the Kemp's ridley sea turtle and quantifies the connection between beach geomorphology and Kemp's ridley nest site selection on PAIS and South Padre Island, Texas. Airborne topographic lidar data collected annually along the Texas coast from 2009 through 2012 was utilized to extract beach geomorphology characteristics, such as beach slope and width, dune height, and surface roughness, among others. The coordinates of observed Kemp's ridley nests from corresponding years were integrated with the aforementioned data in statistical models, which analyzed the influence of both general trends in geomorphology and individual morphologic variables on nest site selection. This research identified the terrestrial habitat variability of the Kemp's ridley and quantified the range of geomorphic characteristics of nesting beaches. Initial results indicate that dune width, beach width, and wind speed are significant variables in relation to nest presence, using an alpha of 0.1. Higher wind speeds and narrower beaches and foredunes favor nest presence. The average nest elevation is 1.13 m above mean sea level, which corresponds to the area directly below the potential vegetation line, and the majority of nesting occurs between the elevations of 0.68 m and 1.4 m above mean sea level. The results of this study include new information regarding Kemp's ridley beach habitat and its influence on nesting patterns that could be useful for the conservation and management of the species.

Encroachment of Human Activity on Sea Turtle Nesting Sites

NASA Astrophysics Data System (ADS)

Ziskin, D.; Aubrecht, C.; Elvidge, C.; Tuttle, B.; Baugh, K.; Ghosh, T.

2008-12-01

The encroachment of anthropogenic lighting on sea turtle nesting sites poses a serious threat to the survival of these animals [Nicholas, 2001]. This danger is quantified by combining two established data sets. The first is the Nighttime Lights data produced by the NOAA National Geophysical Data Center [Elvidge et al., 1997]. The second is the Marine Turtle Database produced by the World Conservation Monitoring Centre (WCMC). The technique used to quantify the threat of encroachment is an adaptation of the method described in Aubrecht et al. [2008], which analyzes the stress on coral reef systems by proximity to nighttime lights near the shore. Nighttime lights near beaches have both a direct impact on turtle reproductive success since they disorient hatchlings when they mistake land-based lights for the sky-lit surf [Lorne and Salmon, 2007] and the lights are also a proxy for other anthropogenic threats. The identification of turtle nesting sites with high rates of encroachment will hopefully steer conservation efforts to mitigate their effects [Witherington, 1999]. Aubrecht, C, CD Elvidge, T Longcore, C Rich, J Safran, A Strong, M Eakin, KE Baugh, BT Tuttle, AT Howard, EH Erwin, 2008, A global inventory of coral reef stressors based on satellite observed nighttime lights, Geocarto International, London, England: Taylor and Francis. In press. Elvidge, CD, KE Baugh, EA Kihn, HW Kroehl, ER Davis, 1997, Mapping City Lights with Nighttime Data from the DMSP Operational Linescan System, Photogrammatic Engineering and Remote Sensing, 63:6, pp. 727-734. Lorne, JK, M Salmon, 2007, Effects of exposure to artificial lighting on orientation of hatchling sea turtles on the beach and in the ocean, Endangered Species Research, Vol. 3: 23-30. Nicholas, M, 2001, Light Pollution and Marine Turtle Hatchlings: The Straw that Breaks the Camel's Back?, George Wright Forum, 18:4, p77-82. Witherington, BE, 1999, Reducing Threats To Nesting Habitat, Research and Management Techniques for the Conservation of Sea Turtles, KL Eckert, KA Bjorndal, FAA Grobois, M Donnelly, eds., IUCN/SSC Marine Turtle Specialist Group.

mtDNA variation of the critically endangered hawksbill turtle (Eretmochelys imbricata) nesting on Iranian islands of the Persian Gulf.

PubMed

Tabib, M; Zolgharnein, H; Mohammadi, M; Salari-Aliabadi, M A; Qasemi, A; Roshani, S; Rajabi-Maham, H; Frootan, F

2011-01-01

Genetic diversity of sea turtles (hawksbill turtle) was studied using sequencing of mitochondrial DNA (mtDNA, D-loop region). Thirty dead embryos were collected from the Kish and Qeshm Islands in the Persian Gulf. Analysis of sequence variation over 890 bp of the mtDNA control region revealed five haplotypes among 30 individuals. This is the first time that Iranian haplotypes have been recorded. Nucleotide and haplotype diversity was 0.77 and 0.001 for Qeshm Island and 0.64 and 0.002 for Kish Island, respectively. Total haplotype diversity was calculated as 0.69, which demonstrates low genetic diversity in this area. The data also indicated very high rates of migration between the populations of these two islands. A comparison of our data with data from previous studies downloaded from a gene bank showed that turtles of the Persian Gulf migrated from the Pacific and the Sea of Oman into this area. On the other hand, evidence of migration from populations to the West was not found.

Variability in age and size at maturation, reproductive longevity, and long-term growth dynamics for Kemp's ridley sea turtles in the Gulf of Mexico

PubMed Central

Goshe, Lisa R.; Coggins, Lewis; Shaver, Donna J.; Higgins, Ben; Landry, Andre M.; Bailey, Rhonda

2017-01-01

Effective management of protected sea turtle populations requires knowledge not only of mean values for demographic and life-history parameters, but also temporal and spatial trends, variability, and underlying causes. For endangered Kemp’s ridley sea turtles (Lepidochelys kempii), the need for baseline information of this type has been emphasized during attempts to understand causes underlying the recent truncation in the recovery trajectory for nesting females. To provide insight into variability in age and size at sexual maturation (ASM and SSM) and long-term growth patterns likely to influence population trends, we conducted skeletochronological analysis of humerus bones from 333 Kemp’s ridleys stranded throughout the Gulf of Mexico (GOM) from 1993 to 2010. Ranges of possible ASMs (6.8 to 21.8 yr) and SSMs (53.3 to 68.3 cm straightline carapace length (SCL)) estimated using the “rapprochement” skeletal growth mark associated with maturation were broad, supporting incorporation of a maturation schedule in Kemp’s ridley population models. Mean ASMs estimated from rapprochement and by fitting logistic, generalized additive mixed, and von Bertalanffy growth models to age and growth data ranged from 11 to 13 yr; confidence intervals for the logistic model predicted maturation of 95% of the population between 11.9 and 14.8 yr. Early juvenile somatic growth rates in the GOM were greater than those previously reported for the Atlantic, indicating potential for differences in maturation trajectories between regions. Finally, long-term, significant decreases in somatic growth response were found for both juveniles and adults, which could influence recruitment to the reproductive population and observed nesting population trends. PMID:28333937

Variability in age and size at maturation, reproductive longevity, and long-term growth dynamics for Kemp's ridley sea turtles in the Gulf of Mexico.

PubMed

Avens, Larisa; Goshe, Lisa R; Coggins, Lewis; Shaver, Donna J; Higgins, Ben; Landry, Andre M; Bailey, Rhonda

2017-01-01

Effective management of protected sea turtle populations requires knowledge not only of mean values for demographic and life-history parameters, but also temporal and spatial trends, variability, and underlying causes. For endangered Kemp's ridley sea turtles (Lepidochelys kempii), the need for baseline information of this type has been emphasized during attempts to understand causes underlying the recent truncation in the recovery trajectory for nesting females. To provide insight into variability in age and size at sexual maturation (ASM and SSM) and long-term growth patterns likely to influence population trends, we conducted skeletochronological analysis of humerus bones from 333 Kemp's ridleys stranded throughout the Gulf of Mexico (GOM) from 1993 to 2010. Ranges of possible ASMs (6.8 to 21.8 yr) and SSMs (53.3 to 68.3 cm straightline carapace length (SCL)) estimated using the "rapprochement" skeletal growth mark associated with maturation were broad, supporting incorporation of a maturation schedule in Kemp's ridley population models. Mean ASMs estimated from rapprochement and by fitting logistic, generalized additive mixed, and von Bertalanffy growth models to age and growth data ranged from 11 to 13 yr; confidence intervals for the logistic model predicted maturation of 95% of the population between 11.9 and 14.8 yr. Early juvenile somatic growth rates in the GOM were greater than those previously reported for the Atlantic, indicating potential for differences in maturation trajectories between regions. Finally, long-term, significant decreases in somatic growth response were found for both juveniles and adults, which could influence recruitment to the reproductive population and observed nesting population trends.

Nest-niche differentiation in two sympatric columbid species from a Mediterranean Tetraclinis woodland: Considerations for forest management

NASA Astrophysics Data System (ADS)

Hanane, Saâd; Yassin, Mohamed

2017-01-01

Studies of niche partitioning among Columbid species have mainly addressed food habits and foraging activities, while partitioning in relation to nest-niche differentiation has been little studied. Here we investigate whether two sympatric columbid species-Woodpigeon (Columba palumbus) and Turtle dove (Streptopelia turtur)-occupy similar niches. A total of 74 nests were monitored: 37 nests for each species. The study, conducted in June 2016, attempted to determine the factors that may play a role in nest-niche differentiation among the two sympatric columbid species in a Moroccan Thuya (Tetraclinis articulata) forest. We used Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) to test the relevance of nest placement, proximity of food resources, forest edge and human presence variables in the nest distribution of the two species. The results show substantial niche segregation in the T. articulata nest-trees selected by Woodpigeons and Turtle doves, with selection depending primarily on the tree size and nest height. Observed nest-niche partitioning may diminish the potential for competition between these species and enhance opportunities for their coexistence. Management policies and practices aimed at ensuring the presence of mixed-sized class of Thuya trees must be prioritized. We recommend additional studies designed to: (1) reproduce the same experimental approach on other Mediterranean Thuya forests to improve our understanding of the effects of different levels of anthropogenic disturbance on the breeding behaviour of these two game species; (2) better understand the spatio-temporal dynamics of Woodpigeon and Turtle dove coexistence in the region; and (3) better identify the spatio-temporal extent of the effect of forest management on Woodpigeon and Turtle dove site occupancy.

Male hatchling production in sea turtles from one of the world’s largest marine protected areas, the Chagos Archipelago

PubMed Central

Esteban, Nicole; Laloë, Jacques-Olivier; Mortimer, Jeanne A.; Guzman, Antenor N.; Hays, Graeme C.

2016-01-01

Sand temperatures at nest depths and implications for hatchling sex ratios of hawksbill turtles (Eretmochelys imbricata) and green turtles (Chelonia mydas) nesting in the Chagos Archipelago, Indian Ocean are reported and compared to similar measurements at rookeries in the Atlantic and Caribbean. During 2012–2014, temperature loggers were buried at depths and in beach zones representative of turtle nesting sites. Data collected for 12,546 days revealed seasonal and spatial patterns of sand temperature. Depth effects were minimal, perhaps modulated by shade from vegetation. Coolest and warmest temperatures were recorded in the sites heavily shaded in vegetation during the austral winter and in sites partially shaded in vegetation during summer respectively. Overall, sand temperatures were relatively cool during the nesting seasons of both species which would likely produce fairly balanced hatchling sex ratios of 53% and 63% male hatchlings, respectively, for hawksbill and green turtles. This result contrasts with the predominantly high female skew reported for offspring at most rookeries around the globe and highlights how local beach characteristics can drive incubation temperatures. Our evidence suggests that sites characterized by heavy shade associated with intact natural vegetation are likely to provide conditions suitable for male hatchling production in a warming world. PMID:26832230

Male hatchling production in sea turtles from one of the world’s largest marine protected areas, the Chagos Archipelago

NASA Astrophysics Data System (ADS)

Esteban, Nicole; Laloë, Jacques-Olivier; Mortimer, Jeanne A.; Guzman, Antenor N.; Hays, Graeme C.

2016-02-01

Sand temperatures at nest depths and implications for hatchling sex ratios of hawksbill turtles (Eretmochelys imbricata) and green turtles (Chelonia mydas) nesting in the Chagos Archipelago, Indian Ocean are reported and compared to similar measurements at rookeries in the Atlantic and Caribbean. During 2012-2014, temperature loggers were buried at depths and in beach zones representative of turtle nesting sites. Data collected for 12,546 days revealed seasonal and spatial patterns of sand temperature. Depth effects were minimal, perhaps modulated by shade from vegetation. Coolest and warmest temperatures were recorded in the sites heavily shaded in vegetation during the austral winter and in sites partially shaded in vegetation during summer respectively. Overall, sand temperatures were relatively cool during the nesting seasons of both species which would likely produce fairly balanced hatchling sex ratios of 53% and 63% male hatchlings, respectively, for hawksbill and green turtles. This result contrasts with the predominantly high female skew reported for offspring at most rookeries around the globe and highlights how local beach characteristics can drive incubation temperatures. Our evidence suggests that sites characterized by heavy shade associated with intact natural vegetation are likely to provide conditions suitable for male hatchling production in a warming world.

Male hatchling production in sea turtles from one of the world's largest marine protected areas, the Chagos Archipelago.

PubMed

Esteban, Nicole; Laloë, Jacques-Olivier; Mortimer, Jeanne A; Guzman, Antenor N; Hays, Graeme C

2016-02-02

Sand temperatures at nest depths and implications for hatchling sex ratios of hawksbill turtles (Eretmochelys imbricata) and green turtles (Chelonia mydas) nesting in the Chagos Archipelago, Indian Ocean are reported and compared to similar measurements at rookeries in the Atlantic and Caribbean. During 2012-2014, temperature loggers were buried at depths and in beach zones representative of turtle nesting sites. Data collected for 12,546 days revealed seasonal and spatial patterns of sand temperature. Depth effects were minimal, perhaps modulated by shade from vegetation. Coolest and warmest temperatures were recorded in the sites heavily shaded in vegetation during the austral winter and in sites partially shaded in vegetation during summer respectively. Overall, sand temperatures were relatively cool during the nesting seasons of both species which would likely produce fairly balanced hatchling sex ratios of 53% and 63% male hatchlings, respectively, for hawksbill and green turtles. This result contrasts with the predominantly high female skew reported for offspring at most rookeries around the globe and highlights how local beach characteristics can drive incubation temperatures. Our evidence suggests that sites characterized by heavy shade associated with intact natural vegetation are likely to provide conditions suitable for male hatchling production in a warming world.

Hatching behavior in turtles.

PubMed

Spencer, Ricky-John; Janzen, Fredric J

2011-07-01

Incubation temperature plays a prominent role in shaping the phenotypes and fitness of embryos, including affecting developmental rates. In many taxa, including turtles, eggs are deposited in layers such that thermal gradients alter developmental rates within a nest. Despite this thermal effect, a nascent body of experimental work on environmentally cued hatching in turtles has revealed unexpected synchronicity in hatching behavior. This review discusses environmental cues for hatching, physiological mechanisms behind synchronous hatching, proximate and ultimate causes for this behavior, and future directions for research. Four freshwater turtle species have been investigated experimentally, with hatching in each species elicited by different environmental cues and responding via various physiological mechanisms. Hatching of groups of eggs in turtles apparently involves some level of embryo-embryo communication and thus is not a purely passive activity. Although turtles are not icons of complex social behavior, life-history theory predicts that the group environment of the nest can drive the evolution of environmentally cued hatching.

The interplay of homing and dispersal in green turtles: a focus on the southwestern atlantic.

PubMed

Naro-Maciel, Eugenia; Bondioli, Ana Cristina Vigliar; Martin, Meredith; de Pádua Almeida, Antônio; Baptistotte, Cecília; Bellini, Claudio; Marcovaldi, Maria Ângela; Santos, Armando José Barsante; Amato, George

2012-01-01

Current understanding of spatial ecology is insufficient in many threatened marine species, failing to provide a solid basis for conservation and management. To address this issue for globally endangered green turtles, we investigated their population distribution by sequencing a mitochondrial control region segment from the Rocas Atoll courtship area (n = 30 males) and four feeding grounds (FGs) in Brazil (n = 397), and compared our findings to published data (n (nesting) = 1205; n (feeding) = 1587). At Rocas Atoll, the first Atlantic courtship area sequenced to date, we found males were differentiated from local juveniles but not from nesting females. In combination with tag data, this indicates possible male philopatry. The most common haplotypes detected at the study sites were CMA-08 and CMA-05, and significant temporal variation was not revealed. Although feeding grounds were differentiated overall, intra-regional structure was less pronounced. Ascension was the primary natal source of the study FGs, with Surinam and Trindade as secondary sources. The study clarified the primary connectivity between Trindade and Brazil. Possible linkages to African populations were considered, but there was insufficient resolution to conclusively determine this connection. The distribution of FG haplotype lineages was nonrandom and indicative of regional clustering. The study investigated impacts of population size, geographic distance, ocean currents, and juvenile natal homing on connectivity, addressed calls for increased genetic sampling in the southwestern Atlantic, and provided data important for conservation of globally endangered green turtles.

Maternal transfer and sublethal immune system effects of brevetoxin exposure in nesting loggerhead sea turtles (Caretta caretta) from western Florida.

PubMed

Perrault, Justin R; Bauman, Katherine D; Greenan, Taylor M; Blum, Patricia C; Henry, Michael S; Walsh, Catherine J

2016-11-01

Blooms of Karenia brevis (also called red tides) occur almost annually in the Gulf of Mexico. The health effects of the neurotoxins (i.e., brevetoxins) produced by this toxic dinoflagellate on marine turtles are poorly understood. Florida's Gulf Coast represents an important foraging and nesting area for a number of marine turtle species. Most studies investigating brevetoxin exposure in marine turtles thus far focus on dead and/or stranded individuals and rarely examine the effects in apparently "healthy" free-ranging individuals. From May-July 2014, one year after the last red tide bloom, we collected blood from nesting loggerhead sea turtles (Caretta caretta) on Casey Key, Florida USA. These organisms show both strong nesting and foraging site fidelity. The plasma was analyzed for brevetoxin concentrations in addition to a number of health and immune-related parameters in an effort to establish sublethal effects of this toxin. Lastly, from July-September 2014, we collected unhatched eggs and liver and yolk sacs from dead-in-nest hatchlings from nests laid by the sampled females and tested these samples for brevetoxin concentrations to determine maternal transfer and effects on reproductive success. Using a competitive enzyme-linked immunosorbent assay (ELISA), all plasma samples from nesting females tested positive for brevetoxin (reported as ng brevetoxin-3[PbTx-3] equivalents [eq]/mL) exposure (2.1-26.7ng PbTx-3eq/mL). Additionally, 100% of livers (1.4-13.3ng PbTx-3eq/mL) and yolk sacs (1.7-6.6ng PbTx-3eq/mL) from dead-in-nest hatchlings and 70% of eggs (<1.0-24.4ng PbTx-3eq/mL) tested positive for brevetoxin exposure with the ELISA. We found that plasma brevetoxin concentrations determined by an ELISA in nesting females positively correlated with gamma-globulins, indicating a potential for immunomodulation as a result of brevetoxin exposure. While the sample sizes were small, we also found that plasma brevetoxin concentrations determined by an ELISA in nesting females significantly correlated with liver brevetoxin concentrations of dead-in-nest hatchlings and that brevetoxins could be related to a decreased reproductive success in this species. This study suggests that brevetoxins can still elicit negative effects on marine life long after a bloom has dissipated. These results improve our understanding of maternal transfer and sublethal effects of brevetoxin exposure in marine turtles. Copyright © 2016 Elsevier B.V. All rights reserved.

Post-Wildfire Potential for Carbon and Nitrogen Sequestration in the Southwestern United States in Restored Ephemeral and Intermittent Stream Channels

NASA Astrophysics Data System (ADS)

Callegary, J. B.; Norman, L.; Eastoe, C. J.; Sankey, J. B.; Youberg, A.

2016-12-01

The Kemp's ridley sea turtle (Lepidochelys kempii) is the most endangered sea turtle in the world, largely due to the limited geographic range of its nesting habitat. In the U.S., the majority of nesting occurs along Padre Island National Seashore (PAIS) in Texas. There has been limited research regarding the connection between beach geomorphology and Kemp's ridley nesting patterns, but studies concerning other sea turtle species suggest that certain beach geomorphology variables, such as beach slope and width, influence nest site selection. This research investigates terrestrial habitat variability of the Kemp's ridley sea turtle and quantifies the connection between beach geomorphology and Kemp's ridley nest site selection on PAIS and South Padre Island, Texas. Airborne topographic lidar data collected annually along the Texas coast from 2009 through 2012 was utilized to extract beach geomorphology characteristics, such as beach slope and width, dune height, and surface roughness, among others. The coordinates of observed Kemp's ridley nests from corresponding years were integrated with the aforementioned data in statistical models, which analyzed the influence of both general trends in geomorphology and individual morphologic variables on nest site selection. This research identified the terrestrial habitat variability of the Kemp's ridley and quantified the range of geomorphic characteristics of nesting beaches. Initial results indicate that dune width, beach width, and wind speed are significant variables in relation to nest presence, using an alpha of 0.1. Higher wind speeds and narrower beaches and foredunes favor nest presence. The average nest elevation is 1.13 m above mean sea level, which corresponds to the area directly below the potential vegetation line, and the majority of nesting occurs between the elevations of 0.68 m and 1.4 m above mean sea level. The results of this study include new information regarding Kemp's ridley beach habitat and its influence on nesting patterns that could be useful for the conservation and management of the species.

Residency and movement patterns of an apex predatory shark (Galeocerdo cuvier) at the Galapagos Marine Reserve.

PubMed

Acuña-Marrero, David; Smith, Adam N H; Hammerschlag, Neil; Hearn, Alex; Anderson, Marti J; Calich, Hannah; Pawley, Matthew D M; Fischer, Chris; Salinas-de-León, Pelayo

2017-01-01

The potential effectiveness of marine protected areas (MPAs) as a conservation tool for large sharks has been questioned due to the limited spatial extent of most MPAs in contrast to the complex life history and high mobility of many sharks. Here we evaluated the movement dynamics of a highly migratory apex predatory shark (tiger shark Galeocerdo cuvier) at the Galapagos Marine Reserve (GMR). Using data from satellite tracking passive acoustic telemetry, and stereo baited remote underwater video, we estimated residency, activity spaces, site fidelity, distributional abundances and migration patterns from the GMR and in relation to nesting beaches of green sea turtles (Chelonia mydas), a seasonally abundant and predictable prey source for large tiger sharks. Tiger sharks exhibited a high degree of philopatry, with 93% of the total satellite-tracked time across all individuals occurring within the GMR. Large sharks (> 200 cm TL) concentrated their movements in front of the two most important green sea turtle-nesting beaches in the GMR, visiting them on a daily basis during nocturnal hours. In contrast, small sharks (< 200 cm TL) rarely visited turtle-nesting areas and displayed diurnal presence at a third location where only immature sharks were found. Small and some large individuals remained in the three study areas even outside of the turtle-nesting season. Only two sharks were satellite-tracked outside of the GMR, and following long-distance migrations, both individuals returned to turtle-nesting beaches at the subsequent turtle-nesting season. The spatial patterns of residency and site fidelity of tiger sharks suggest that the presence of a predictable source of prey and suitable habitats might reduce the spatial extent of this large shark that is highly migratory in other parts of its range. This highly philopatric behaviour enhances the potential effectiveness of the GMR for their protection.

Residency and movement patterns of an apex predatory shark (Galeocerdo cuvier) at the Galapagos Marine Reserve

PubMed Central

Smith, Adam N. H.; Hammerschlag, Neil; Hearn, Alex; Anderson, Marti J.; Calich, Hannah; Pawley, Matthew D. M.; Fischer, Chris; Salinas-de-León, Pelayo

2017-01-01

The potential effectiveness of marine protected areas (MPAs) as a conservation tool for large sharks has been questioned due to the limited spatial extent of most MPAs in contrast to the complex life history and high mobility of many sharks. Here we evaluated the movement dynamics of a highly migratory apex predatory shark (tiger shark Galeocerdo cuvier) at the Galapagos Marine Reserve (GMR). Using data from satellite tracking passive acoustic telemetry, and stereo baited remote underwater video, we estimated residency, activity spaces, site fidelity, distributional abundances and migration patterns from the GMR and in relation to nesting beaches of green sea turtles (Chelonia mydas), a seasonally abundant and predictable prey source for large tiger sharks. Tiger sharks exhibited a high degree of philopatry, with 93% of the total satellite-tracked time across all individuals occurring within the GMR. Large sharks (> 200 cm TL) concentrated their movements in front of the two most important green sea turtle-nesting beaches in the GMR, visiting them on a daily basis during nocturnal hours. In contrast, small sharks (< 200 cm TL) rarely visited turtle-nesting areas and displayed diurnal presence at a third location where only immature sharks were found. Small and some large individuals remained in the three study areas even outside of the turtle-nesting season. Only two sharks were satellite-tracked outside of the GMR, and following long-distance migrations, both individuals returned to turtle-nesting beaches at the subsequent turtle-nesting season. The spatial patterns of residency and site fidelity of tiger sharks suggest that the presence of a predictable source of prey and suitable habitats might reduce the spatial extent of this large shark that is highly migratory in other parts of its range. This highly philopatric behaviour enhances the potential effectiveness of the GMR for their protection. PMID:28829820

Flexible foraging movements of leatherback turtles across the North Atlantic Ocean.

PubMed

Hays, Graeme C; Hobson, Victoria J; Metcalfe, Julian D; Righton, David; Sims, David W

2006-10-01

Some marine species have been shown to target foraging at particular hotspots of high prey abundance. However, we show here that in the year after a nesting season, female leatherback turtles (Dermochelys coriacea) in the Atlantic generally spend relatively little time in fixed hotspots, especially those with a surface signature revealed in satellite imagery, but rather tend to have a pattern of near continuous traveling. Associated with this traveling, distinct changes in dive behavior indicate that turtles constantly fine tune their foraging behavior and diel activity patterns in association with local conditions. Switches between nocturnal vs. diurnal activity are rare in the animal kingdom but may be essential for survival on a diet of gelatinous zooplankton where patches of high prey availability are rare. These results indicate that in their first year after nesting, leatherback turtles do not fit the general model of migration where responses to resources are suppressed during transit. However, their behavior may be different in their sabbatical years away from nesting beaches. Our results highlight the importance of whole-ocean fishing gear regulations to minimize turtle bycatch.

Chemosensory orientation behavior in juvenile sea turtles.

PubMed

Grassman, M

1993-01-01

It has been widely believed for several decades that hatchling sea turtles imprint to chemical cues characteristic of their natal beach and use this information as part of a repertoire of mechanisms enabling their return to the same beach for mating and nesting. This has proven very difficult to test. Although the imprinting theory is conceptually simple, functionally it is quite complex. This involves not only chemical imprinting of nestlings but growth and migration to habitats where the adults are found, long-term memory of their earlier chemical exposure, reproductive maturation, and homing. A few studies have been conducted to examine these elements of the imprinting theory. Experiments involving the exposure of embryos and hatchlings to chemicals suggest that juvenile turtles 'imprint' to the chemical environment of their nest. This can be termed chemical imprinting. Loggerhead turtles, Caretta caretta, and ridley turtles, Lepidochelys kempi, appear to be attracted to chemicals (morpholine and natural seawater, respectively) to which they were exposed as embryos. The strongest support for chemical imprinting is that six-month-old green turtles, Chelonia mydas, exposed to either morpholine or 2-phenylethanol in the nest and for a period of time after hatching, respond similarly to the chemical to which they were exposed as nestlings. Although chemical imprinting does not 'prove' the imprinting theory of turtle homing, it is a necessary component of the theory not previously examined.

Deepwater Horizon oil spill impacts on sea turtles could span the Atlantic

PubMed Central

Putman, Nathan F.; Abreu-Grobois, F. Alberto; Iturbe-Darkistade, Iñaky; Putman, Emily M.; Richards, Paul M.; Verley, Philippe

2015-01-01

We investigated the extent that the 2010 Deepwater Horizon oil spill potentially affected oceanic-stage sea turtles from populations across the Atlantic. Within an ocean-circulation model, particles were backtracked from the Gulf of Mexico spill site to determine the probability of young turtles arriving in this area from major nesting beaches. The abundance of turtles in the vicinity of the oil spill was derived by forward-tracking particles from focal beaches and integrating population size, oceanic-stage duration and stage-specific survival rates. Simulations indicated that 321 401 (66 199–397 864) green (Chelonia mydas), loggerhead (Caretta caretta) and Kemp's ridley (Lepidochelys kempii) turtles were likely within the spill site. These predictions compared favourably with estimates from in-water observations recently made available to the public (though our initial predictions for Kemp's ridley were substantially lower than in-water estimates, better agreement was obtained with modifications to mimic behaviour of young Kemp's ridley turtles in the northern Gulf). Simulations predicted 75.2% (71.9–76.3%) of turtles came from Mexico, 14.8% (11–18%) from Costa Rica, 5.9% (4.8–7.9%) from countries in northern South America, 3.4% (2.4–3.5%) from the United States and 1.6% (0.6–2.0%) from West African countries. Thus, the spill's impacts may extend far beyond the current focus on the northern Gulf of Mexico. PMID:26701754

Metabolic heating and the prediction of sex ratios for green turtles (Chelonia mydas).

PubMed

Broderick, A C; Godley, B J; Hays, G C

2001-01-01

We compared incubation temperatures in nests (n=32) of the green turtle (Chelonia mydas) on Ascension Island in relation to sand temperatures of control sites at nest depth. Intrabeach thermal variation was low, whereas interbeach thermal variation was high in both control and nest sites. A marked rise in temperature was recorded in nests from 30% to 40% of the way through the incubation period and attributed to metabolic heating. Over the entire incubation period, metabolic heating accounted for a mean rise in temperature of between 0.07 degrees and 2.86 degrees C within nests. During the middle third of incubation, when sex is thought to be determined, this rise in temperature ranged between 0.07 degrees and 2.61 degrees C. Metabolic heating was related to both the number of eggs laid and the total number of hatchlings/embryos produced in a clutch. For 32 clutches in which temperature was recorded, we estimate that metabolic heating accounted for a rise of up to 30% in the proportion of females produced within different clutches. Previous studies have dismissed any effect of metabolic heating on the sex ratio of marine turtle hatchlings. Our results imply that metabolic heating needs to be considered when estimating green turtle hatchling sex ratios.

Increased levels of arginine vasotocin and neurophysin during nesting in sea turtles.

PubMed

Figler, R A; MacKenzie, D S; Owens, D W; Licht, P; Amoss, M S

1989-02-01

Arginine vasotocin (AVT) and neurophysin (NP) levels were measured by radioimmunoassay in two species of sea turtle, the olive ridley, Lepidochelys olivacea, and the loggerhead, Caretta caretta, during the brief period of nesting and oviposition. In both species, AVT was low in animals which were not reproductively active. AVT was also low at the time animals emerged from the surf to nest, but increased significantly during oviposition and then declined as the animals returned to the water. NP increased in concert with AVT, also reaching highest levels during oviposition. In both species, however, NP levels remained elevated over prenesting levels at the time of return to the water. These findings are consistent with the hypothesis that an AVT-neurophysin complex is released from the neurohypophysis during nesting, and that AVT is a physiological regulator of oviducal contractions in sea turtles.

Yolk embolism associated with trauma in vitellogenic sea turtles in Florida (USA): a review of 11 cases.

PubMed

Stacy, Brian A; Foley, Allen; Garner, Michael M; Mettee, Nancy

2013-12-01

Case information and postmortem examination findings are presented for 11 adult female sea turtles in reproductive form that died in Florida, USA. All had abundant, large vitellogenic follicles, and most were either gravid or had recently nested. Species included six loggerheads (Caretta caretta) and five green turtles (Chelonia mydas). Identified proximate causes of death included falls or entrapment by obstructions on nesting beaches, burial under collapsed dunes, and other traumatic injuries of different causes. Evidence of yolk embolization was found in 10 cases and suspected in an 11th turtle. Ten turtles also had various amounts of free intracoelomic yolk. Although the effects of yolk embolization are uncertain at this time, precedence of pathologic importance in other species suggests that embolism may complicate traumatic injuries, including seemingly minor events.

Environmental Impact Research Program. Life History and Environmental Requirements of Loggerhead Sea Turtles.

DTIC Science & Technology

1986-01-01

green turtles dig a deep body pit when nesting. LIFE HISTORY - 5. The greatest...were loggerheads, but greens and Kemp’s ridleys were also found . (Joyce 1982). Since the turtles were discovered during the winter, were covered...Preferences in the Loggerhead Sea Turtle , Caretta caretta," Copeia, Vol 1982, No. 4, pp 965-969. Hendrickson, J. R. 1958. " The Green Sea Turtle

Sea turtles, light pollution, and citizen science: A preliminary report

USGS Publications Warehouse

Afford, Heather; Teel, Susan; Nicholas, Mark; Stanley, Thomas; White, Jeremy

2017-01-01

such as entanglement in fishing gear and ingestion of marine debris, as well as possible changes in sex ratios due to increasing temperatures related to human-induced global warming. Locally, light pollution from residential, commercial, and industrial neighborhoods from nearby cities impacts the entirety of Gulf Islands, which spans 160 miles along the Gulf Coast, from Florida to Mississippi, and includes critical habitat for threatened and endangered sea turtles. Because light pollution has been hypothesized to negatively impact sea turtle nesting and hatchling survival, Gulf Islands undertook an effort to understand the relationship between light pollution and sea turtles and create unique educational and outreach opportunities by launching a citizen science program called Turtle Teens Helping in the Seashore (Turtle THIS). At the onset, the Turtle THIS program had two primary goals: quantify the association between light pollution and sea turtle nesting and hatching events using rigorous scientific methods; and initiate a citizen science volunteer program to provide youth with hands-on science and environmental stewardship roles, where they also gain employable skills and career opportunities. With multiple scientific hypotheses to consider, the development of a citizen science program became crucial. Such circumstances allowed Turtle THIS to grow a volunteer and intern program, quantify hypothesized light effects on sea turtles through developed methods, and begin to gather preliminary findings.

Constant Temperature Artificial Incubation of Spawned Eggs in Natural Nests from the Chinese Freshwater Soft-Shelled Turtle, Tryonyx sinensis Strauch(1862)

PubMed Central

Oh, Young Nam; Kim, Sung Han

2017-01-01

ABSTRACT On June 14, 2008 (the first experiment) and July 24, 2008 (the second experiment), the shores of the Boseong River and the sandy beaches, Seokgok-myun, Moksadong-myun, Gokseong-gun in Jeollanam Province were investigated and a total of 29 soft-shelled turtle (Tryonyx sinensis) eggs in the natural spawning nest eggs were collected (13 eggs were collected in the first experiment and 16 eggs in the second experiment). The temperatures in the natural spawning nests were 25.9-36.9±0.5℃, the depth of the eggs was 5.2-7.5±0.5 cm as the distance of the average 6.4±0.5 cm. 29 eggs were scattered at least 0.2 cm interval. Artificial incubation of 29 eggs was conducted in artificial nest boxes in thermo-plastic composition of the incubator, and then incubated at 26.5-35.5±0.5℃, and an average constant temperature was 31.2-32.1±1.0℃. The incubation days ranged from 53 to 55. In case of most turtles, incubation at 31℃ (higher temperatures) generally produces all or mostly females, while incubation at 25℃(cooler temperatures) produces all or mostly males. Exceptionally, in case of genus Trionyx, the sex ratio of female : male of T. sinensis of a freshwater soft-shelled turtle was approximately 1:1, which differs from other genera of turtles and makes T. sinensis Strauch only turtles presently known to lack temperature-dependent sex determination. PMID:28484749

[Clusters of Fusarium solani infection in juvenile captive born Caretta caretta sea turtles].

PubMed

Garcia-Hartmann, M; Hennequin, C; Catteau, S; Béatini, C; Blanc, V

2017-03-01

Various yeasts and filamentous fungi are described as the cause of infection in sea turtles. Among them, Fusarium solani is responsible both for superficial and invasive infection in weakened adults (capture, stranding), and wild nest contamination, causing massive losses during hatching. We illustrate the pathogenicity of this fungus in sea turtles, through our experience with the species Caretta caretta (loggerhead turtle) and its reproduction, which was obtained for the first time in 2010 at the marine park Marineland, Antibes and renewed in 2011 and 2013. The first generation (6 viable newborns e.g. 0.9% of the nest) was severely affected by an infectious agent causing skin and multifocal organ lesions. Microbiological samples allowed to establish F. solani as the etiological agent. Antifungal therapy with posaconazole cured 2 (33%) of the brood. Epidemiological investigations, infection control and hygiene measures as well as diagnosis criteria, preemptive and curative treatment procedures allowed better prevention and cure and finally higher survival rates in subsequent broods, in 2011 and 2013 (80 viable newborns e.g. 6.6% of the nest and 50% survival rate). F. solani appears as a major threat for the successful reproduction of sea turtles in the wild. As observed, this threat is also of concern during captive breeding. The conditions of transmission and pathogenicity of Fusarium spp. in these animals are discussed in light of the literature cases that occurred in adult sea turtles and in wild nests, and of our breeding experience. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Nesting ecology of Podocnemis expansa (Schweigger, 1812) and Podocnemis unifilis (Troschel, 1848) (Testudines, Podocnemididae) in the Javaés River, Brazil.

PubMed

Ferreira Júnior, P D; Castro, P T A

2010-02-01

Nest site has influence on incubation duration and hatching success of two Neotropical turtles, the giant Amazon River turtle (Podocnemis expansa) and yellow-spotted side-neck turtle (Podocnemis unifilis--'Tracajá'). The 2000 and 2001 nesting seasons have been monitored at the Javaés River in Bananal Island, Brazil. Although they nest on the same beaches, there is a separation of the nesting areas of P unifilis and P. expansa nests on the upper parts of the beach. The incubation duration for P. expansa is influenced by the nesting period, the height of the nest from the river, the clutch size, and the grain size in the site of the nest. Nests of Podocnemis expansa placed in coarse sediments have shorter incubation duration than those placed in finer sediments. The hatching success in P. expansa is influenced by grain size, incubation duration, and nesting period. The grain size is negatively correlated with hatching success, indicating that the nests situated in finer-grained sand have better chances of successful egg hatching than those in coarser-grained sand. Nests of the end of the reproductive season have lower hatching success and incubation duration than those at the start of the season. For P. unifilis, the nesting period and nest depth influence the incubation duration; moreover, the river dynamics significantly affect the hatching success. The oscillation of the river level and the moment of initial increase, the height of the nest from the river level, and the nesting period are all decisive components for hatching success. The results of this research show the importance of protecting areas with great geological diversity, wherein the features of the environment can affect the microenvironment of nests, with consequences on incubation duration and hatching success.

How Much Are Floridians Willing to Pay for Protecting Sea Turtles from Sea Level Rise?

NASA Astrophysics Data System (ADS)

Hamed, Ahmed; Madani, Kaveh; Von Holle, Betsy; Wright, James; Milon, J. Walter; Bossick, Matthew

2016-01-01

Sea level rise (SLR) is posing a great inundation risk to coastal areas. Some coastal nesting species, including sea turtle species, have experienced diminished habitat from SLR. Contingent valuation method (CVM) was used in an effort to assess the economic loss impacts of SLR on sea turtle nesting habitats for Florida coasts; and to elicit values of willingness to pay (WTP) of Central Florida residents to implement certain mitigation strategies, which would protect Florida's east coast sea turtle nesting areas. Using the open-ended and dichotomous choice CVM, we sampled residents of two Florida communities: Cocoa Beach and Oviedo. We estimated the WTP of households from these two cities to protect sea turtle habitat to be between 42 and 57 per year for 5 years. Additionally, we attempted to assess the impact of the both the respondents' demographics and their perception toward various situations on their WTP value. Findings include a negative correlation between the age of a respondent and the probability of an individual willing to pay the hypothetical WTP amount. We found that WTP of an individual was not dependent on prior knowledge of the effects of SLR on sea turtle habitat. The greatest indicators of whether or not an individual was willing to pay to protect sea turtle habitat were the respondents' perception regarding the trustworthiness and efficiency of the party which will implement the conservation measures and their confidence in the conservation methods used. Respondents who perceive sea turtles having an effect on their life were also more likely to pay.

How Much Are Floridians Willing to Pay for Protecting Sea Turtles from Sea Level Rise?

PubMed

Hamed, Ahmed; Madani, Kaveh; Von Holle, Betsy; Wright, James; Milon, J Walter; Bossick, Matthew

2016-01-01

Sea level rise (SLR) is posing a great inundation risk to coastal areas. Some coastal nesting species, including sea turtle species, have experienced diminished habitat from SLR. Contingent valuation method (CVM) was used in an effort to assess the economic loss impacts of SLR on sea turtle nesting habitats for Florida coasts; and to elicit values of willingness to pay (WTP) of Central Florida residents to implement certain mitigation strategies, which would protect Florida's east coast sea turtle nesting areas. Using the open-ended and dichotomous choice CVM, we sampled residents of two Florida communities: Cocoa Beach and Oviedo. We estimated the WTP of households from these two cities to protect sea turtle habitat to be between $42 and $57 per year for 5 years. Additionally, we attempted to assess the impact of the both the respondents' demographics and their perception toward various situations on their WTP value. Findings include a negative correlation between the age of a respondent and the probability of an individual willing to pay the hypothetical WTP amount. We found that WTP of an individual was not dependent on prior knowledge of the effects of SLR on sea turtle habitat. The greatest indicators of whether or not an individual was willing to pay to protect sea turtle habitat were the respondents' perception regarding the trustworthiness and efficiency of the party which will implement the conservation measures and their confidence in the conservation methods used. Respondents who perceive sea turtles having an effect on their life were also more likely to pay.

Decreasing annual nest counts in a globally important loggerhead sea turtle population.

PubMed

Witherington, Blair; Kubilis, Paul; Brost, Beth; Meylan, Anne

2009-01-01

The loggerhead sea turtle (Caretta caretta) nests on sand beaches, has both oceanic and neritic life stages, and migrates internationally. We analyzed an 18-year time series of Index Nesting Beach Survey (Index) nest-count data to describe spatial and temporal trends in loggerhead nesting on Florida (USA) beaches. The Index data were highly resolved: 368 fixed zones (mean length 0.88 km) were surveyed daily during annual 109-day survey seasons. Spatial and seasonal coverage averaged 69% of estimated total nesting by loggerheads in the state. We carried out trend analyses on both annual survey-region nest-count totals (N = 18) and annual zone-level nest densities (N = 18 x 368 = 6624). In both analyses, negative binomial regression models were used to fit restricted cubic spline curves to aggregated nest counts. Between 1989 and 2006, loggerhead nest counts on Florida Index beaches increased and then declined, with a net decrease over the 18-year period. This pattern was evident in both a trend model of annual survey-region nest-count totals and a mixed-effect, "single-region" trend model of annual zone-level nest densities that took into account both spatial and temporal correlation between counts. We also saw this pattern in a zone-level model that allowed trend line shapes to vary between six coastal subregions. Annual mean zone-level nest density declined significantly (-28%; 95% CI: -34% to -21%) between 1989 and 2006 and declined steeply (-43%; 95% CI: -48% to -39%) during 1998-2006. Rates of change in annual mean nest density varied more between coastal subregions during the "mostly increasing" period prior to 1998 than during the "steeply declining" period after 1998. The excellent fits (observed vs. expected count R2 > 0.91) of the mixed-effect zone-level models confirmed the presence of strong, positive, within-zone autocorrelation (R > 0.93) between annual counts, indicating a remarkable year-to-year consistency in the longshore spatial distribution of nests over the survey region. We argue that the decline in annual loggerhead nest counts in peninsular Florida can best be explained by a decline in the number of adult female loggerheads in the population. Causes of this decline are explored.

VALIDATION OF ULTRASOUND AS A NONINVASIVE TOOL TO MEASURE SUBCUTANEOUS FAT DEPTH IN LEATHERBACK SEA TURTLES (DERMOCHELYS CORIACEA).

PubMed

Harris, Heather S; Benson, Scott R; James, Michael C; Martin, Kelly J; Stacy, Brian A; Daoust, Pierre-Yves; Rist, Paul M; Work, Thierry M; Balazs, George H; Seminoff, Jeffrey A

2016-03-01

Leatherback turtles (Dermochelys coriacea) undergo substantial cyclical changes in body condition between foraging and nesting. Ultrasonography has been used to measure subcutaneous fat as an indicator of body condition in many species but has not been applied in sea turtles. To validate this technique in leatherback turtles, ultrasound images were obtained from 36 live-captured and dead-stranded immature and adult turtles from foraging and nesting areas in the Pacific and Atlantic oceans. Ultrasound measurements were compared with direct measurements from surgical biopsy or necropsy. Tissue architecture was confirmed histologically in a subset of turtles. The dorsal shoulder region provided the best site for differentiation of tissues. Maximum fat depth values with the front flipper in a neutral (45-90°) position demonstrated good correlation with direct measurements. Ultrasound-derived fat measurements may be used in the future for quantitative assessment of body condition as an index of health in this critically endangered species.

Validation of ultrasound as a noninvasive tool to measure subcutaneous fat depth in leatherback sea turtles (Dermochelys coriacea)

USGS Publications Warehouse

Harris, Heather S.; Benson, Scott R.; James, Michael C.; Martin, Kelly J.; Stacy, Brian A.; Daoust, Pierre-Yves; Rist, Paul M.; Work, Thierry M.; Balazs, George H.; Seminoff, Jeffrey A.

2016-01-01

Leatherback turtles (Dermochelys coriacea) undergo substantial cyclical changes in body condition between foraging and nesting. Ultrasonography has been used to measure subcutaneous fat as an indicator of body condition in many species but has not been applied in sea turtles. To validate this technique in leatherback turtles, ultrasound images were obtained from 36 live-captured and dead-stranded immature and adult turtles from foraging and nesting areas in the Pacific and Atlantic oceans. Ultrasound measurements were compared with direct measurements from surgical biopsy or necropsy. Tissue architecture was confirmed histologically in a subset of turtles. The dorsal shoulder region provided the best site for differentiation of tissues. Maximum fat depth values with the front flipper in a neutral (45–90°) position demonstrated good correlation with direct measurements. Ultrasound-derived fat measurements may be used in the future for quantitative assessment of body condition as an index of health in this critically endangered species.

Reproductive indices in natural nests of giant Amazon river turtles Podocnemis expansa (Schweigger, 1812) (Testudines, Podocnemididae) in the Environmental Protection Area Meanders of the Araguaia River.

PubMed

Alves-Júnior, J R F; Lustosa, A P G; Bosso, A C S; Balestra, R A M; Bastos, L F; Miranda, L B; Santos, A L Q

2012-02-01

A count was made of unhatched eggs and hatchling live and dead Podocnemis expansa turtles in 327 natural nests located on the beaches of the Environmental Protection Area (EPA) Meanders of the Araguaia River, to determine the percentage of hatching (94.63%), non-hatching (5.37%), survival (94.24%) and hatchling mortality (5.76%), and the average percentage of dead hatchlings during the 15 days in the nursery (0.97%). The mean number of hatchlings per nest was determined from the sum of the number of live and dead hatchlings divided by the total number of nests, while the mean number of eggs per nest was determined from the sum of live and dead hatchlings and unhatched eggs divided by the number of nests. These calculations yielded the following mean values: live hatchlings (88.98 ± 23.94), dead hatchlings (0.37 ± 0.93), unhatched eggs (5.07 ± 9.57), and total number of eggs (94.42 ± 21.30). The reproductive efficiency of the wild population of P. expansa can be affected by many environmental factors such as temperature, humidity and rainfall. In addition, man-made factors like the presence of chemicals in the water and the potential for infectious disease also have significant impact. The reproductive indices data obtained from this study are indispensable for future investigations of hatching anomalies.

Biotic and abiotic factors affect the nest environment of embryonic leatherback turtles, Dermochelys coriacea.

PubMed

Wallace, Bryan P; Sotherland, Paul R; Spotila, James R; Reina, Richard D; Franks, Bryan F; Paladino, Frank V

2004-01-01

Clutches of leatherback turtles, Dermochelys coriacea, have lower hatching success than those of other sea turtles, but causes of high embryonic mortality are unknown. We measured characteristics of clutches along with spatial and temporal changes in PO(2) and temperature during incubation to determine the extent to which they affected the developmental environment of leatherback embryos. Minimum PO(2) in nests decreased as both the total number and mass of metabolizing embryos increased. Increases in both the number and mass of metabolizing embryos caused an increase in maximum nest temperature. However, neither PO(2) nor temperature was correlated with hatching success. Our measurements of relatively high nest PO(2) (lowest 17.1 kPa or 16.9% O(2)) indicate that hypoxia apparently does not cause the low hatching success of leatherback clutches. Oxygen partial pressure increased and temperature decreased from the center toward the periphery of leatherback nests. We inferred from these measurements that positions of eggs within nests vary in quality and potentially affect overall developmental success of entire clutches. The large metabolic mass of leatherback clutches and limits to gas flux imposed by the sand create a situation in which leatherback embryos collectively affect their own environment.

Sex ratio estimations of loggerhead sea turtle hatchlings at Kuriat islands, Tunisia: can minor nesting sites contribute to compensate globally female-biased sex ratio?

PubMed

Jribi, Imed; Bradai, Mohamed Nejmeddine

2014-01-01

Hatchling sex ratios in the loggerhead turtle Caretta caretta were estimated by placing electronic temperature recorders in seven nests at Kuriat islands (Tunisia) during the 2013 nesting season. Based on the mean temperatures during the middle third of the incubation period, and on incubation duration, the sex ratio of hatchlings at Kuriat islands was highly male-biased. Presently, the majority of hatchling sex ratio studies are focused on major nesting areas, whereby the sex ratios are universally believed to be heavily female-biased. Here we present findings from a minor nesting site in the Mediterranean, where the hatchling sex ratio was found to be male-biased, suggesting a potential difference between major and minor nesting sites.

Using expert opinion to prioritize impacts of climate change on sea turtles' nesting grounds.

PubMed

Fuentes, M M P B; Cinner, J E

2010-12-01

Managers and conservationists often need to prioritize which impacts from climate change to deal with from a long list of threats. However, data which allows comparison of the relative impact from climatic threats for decision-making is often unavailable. This is the case for the management of sea turtles in the face of climate change. The terrestrial life stages of sea turtles can be negatively impacted by various climatic processes, such as sea level rise, altered cyclonic activity, and increased sand temperatures. However, no study has systematically investigated the relative impact of each of these climatic processes, making it challenging for managers to prioritize their decisions and resources. To address this we offer a systematic method for eliciting expert knowledge to estimate the relative impact of climatic processes on sea turtles' terrestrial reproductive phase. For this we used as an example the world's largest population of green sea turtles and asked 22 scientists and managers to answer a paper based survey with a series of pair-wise comparison matrices that compared the anticipated impacts from each climatic process. Both scientists and managers agreed that increased sand temperature will likely cause the most threat to the reproductive output of the nGBR green turtle population followed by sea level rise, then altered cyclonic activity. The methodology used proved useful to determine the relative impact of the selected climatic processes on sea turtles' reproductive output and provided valuable information for decision-making. Thus, the methodological approach can potentially be applied to other species and ecosystems of management concern. Copyright © 2009 Elsevier Ltd. All rights reserved.

Blood gases, biochemistry and haematology of Galápagos hawksbill turtles (Eretmochelys imbricata)

PubMed Central

Muñoz-Pérez, Juan Pablo; Hirschfeld, Maximilian; Alarcón-Ruales, Daniela; Denkinger, Judith; Castañeda, Jason Guillermo; García, Juan; Lohmann, Kenneth J.

2017-01-01

Abstract The hawksbill turtle, Eretmochelys imbricata, is a marine chelonian with a circum-global distribution, but the species is critically endangered and has nearly vanished from the eastern Pacific. Although reference blood parameter intervals have been published for many chelonian species and populations, including nesting Atlantic hawksbills, no such baseline biochemical and blood gas values have been reported for wild Pacific hawksbill turtles. Blood samples were drawn from eight hawksbill turtles captured in near shore foraging locations within the Galápagos archipelago over a period of four sequential years; three of these turtles were recaptured and sampled on multiple occasions. Of the eight sea turtles sampled, five were immature and of unknown sex, and the other three were females. A portable blood analyzer was used to obtain near immediate field results for a suite of blood gas and chemistry parameters. Values affected by temperature were corrected in two ways: (i) with standard formulas and (ii) with auto-corrections made by the portable analyzer. A bench top blood chemistry analyzer was used to measure a series of biochemistry parameters from plasma. Standard laboratory haematology techniques were employed for red and white blood cell counts and to determine haematocrit manually, which was compared to the haematocrit values generated by the portable analyzer. The values reported in this study provide reference data that may be useful in comparisons among populations and in detecting changes in health status among Galápagos sea turtles. The findings might also be helpful in future efforts to demonstrate associations between specific biochemical parameters and disease or environmental disasters. PMID:28496982

Blood gases, biochemistry and haematology of Galápagos hawksbill turtles (Eretmochelys imbricata).

PubMed

Muñoz-Pérez, Juan Pablo; Lewbart, Gregory A; Hirschfeld, Maximilian; Alarcón-Ruales, Daniela; Denkinger, Judith; Castañeda, Jason Guillermo; García, Juan; Lohmann, Kenneth J

2017-01-01

The hawksbill turtle, Eretmochelys imbricata , is a marine chelonian with a circum-global distribution, but the species is critically endangered and has nearly vanished from the eastern Pacific. Although reference blood parameter intervals have been published for many chelonian species and populations, including nesting Atlantic hawksbills, no such baseline biochemical and blood gas values have been reported for wild Pacific hawksbill turtles. Blood samples were drawn from eight hawksbill turtles captured in near shore foraging locations within the Galápagos archipelago over a period of four sequential years; three of these turtles were recaptured and sampled on multiple occasions. Of the eight sea turtles sampled, five were immature and of unknown sex, and the other three were females. A portable blood analyzer was used to obtain near immediate field results for a suite of blood gas and chemistry parameters. Values affected by temperature were corrected in two ways: (i) with standard formulas and (ii) with auto-corrections made by the portable analyzer. A bench top blood chemistry analyzer was used to measure a series of biochemistry parameters from plasma. Standard laboratory haematology techniques were employed for red and white blood cell counts and to determine haematocrit manually, which was compared to the haematocrit values generated by the portable analyzer. The values reported in this study provide reference data that may be useful in comparisons among populations and in detecting changes in health status among Galápagos sea turtles. The findings might also be helpful in future efforts to demonstrate associations between specific biochemical parameters and disease or environmental disasters.

Inferring Foraging Areas of Nesting Loggerhead Turtles Using Satellite Telemetry and Stable Isotopes

PubMed Central

Ceriani, Simona A.; Roth, James D.; Evans, Daniel R.; Weishampel, John F.; Ehrhart, Llewellyn M.

2012-01-01

In recent years, the use of intrinsic markers such as stable isotopes to link breeding and foraging grounds of migratory species has increased. Nevertheless, several assumptions still must be tested to interpret isotopic patterns found in the marine realm. We used a combination of satellite telemetry and stable isotope analysis to (i) identify key foraging grounds used by female loggerheads nesting in Florida and (ii) examine the relationship between stable isotope ratios and post-nesting migration destinations. We collected tissue samples for stable isotope analysis from 14 females equipped with satellite tags and an additional 57 untracked nesting females. Telemetry identified three post-nesting migratory pathways and associated non-breeding foraging grounds: (1) a seasonal continental shelf–constrained migratory pattern along the northeast U.S. coastline, (2) a non-breeding residency in southern foraging areas and (3) a residency in the waters adjacent to the breeding area. Isotopic variability in both δ13C and δ15N among individuals allowed identification of three distinct foraging aggregations. We used discriminant function analysis to examine how well δ13C and δ15N predict female post-nesting migration destination. The discriminant analysis classified correctly the foraging ground used for all but one individual and was used to predict putative feeding areas of untracked turtles. We provide the first documentation that the continental shelf of the Mid- and South Atlantic Bights are prime foraging areas for a large number (61%) of adult female loggerheads from the largest loggerhead nesting population in the western hemisphere and the second largest in the world. Our findings offer insights for future management efforts and suggest that this technique can be used to infer foraging strategies and residence areas in lieu of more expensive satellite telemetry, enabling sample sizes that are more representative at the population level. PMID:23028943

Spatial distribution of loggerhead turtle (Caretta caretta) emergences along a highly dynamic beach in the northern Gulf of Mexico

USGS Publications Warehouse

Lamont, Margaret M.; Houser, Chris

2014-01-01

As coastlines change due to sea level rise and an increasing human presence, understanding how species, such as marine turtles, respond to alterations in habitat is necessary for proper management and conservation. Survey data from a major nesting beach in the northern Gulf of Mexico, where a revetment was installed, was used to assess spatial distribution of loggerhead emergences. Through use of Quadrat analysis and piecewise linear regression with breakpoint, we present evidence to suggest that nest site selection in loggerheads is determined in the nearshore environment, and by characteristics such as wave height, alongshore currents, depth and patterns of erosion and accretion. Areas of relatively dense nesting were found in areas with relatively strong alongshore currents, relatively small waves, a steep offshore slope and the largest historical rates of erosion. Areas of relatively dense nesting also corresponded to areas of low nesting success. Both nesting and non-nesting emergences were clustered immediately adjacent to the revetment and at other eroding sites along the beach. These results suggest that alterations to the nearshore environment from activities such as construction of a jetty, dredging or installation of pilings, may impact sea turtle nest distribution alongshore. We also show that piecewise linear regression with breakpoint is a technique that can be used with geomorphological and oceanographic data to predict locations of nest clumping and may be useful for managers at other nesting beaches.

Data of first de-novo transcriptome assembly of a non-model species, hawksbill sea turtle, Eretmochelys imbricate, nesting of the Colombian Caribean.

PubMed

Hernández-Fernández, Javier

2017-12-01

The hawksbill sea turtle, Eretmochelys imbricata, is an endangered species of the Caribbean Colombian coast due to anthropic and natural factors that have decreased their population levels. Little is known about the genes that are involved in their immune system, sex determination, aging and others important functions. The data generated represents RNA sequencing and the first de-novo assembly of transcripts expressed in the blood of the hawksbill sea turtle. The raw FASTQ files were deposited in the NCBI SRA database with accession number SRX2653641. A total of 5.7 Gb raw sequence data were obtained, corresponding to 47,555,108 raw reads. Trinity was used to perform a first de-novo assembly, and we were able to identify 47,586 transcripts of the female hawksbill turtle transcriptome with an N50 of 1100 bp. The obtained transcriptome data will be useful for further studies of the physiology, biochemistry and evolution in this species.

Nesting phenology of marine turtles: insights from a regional comparative analysis on green turtle (Chelonia mydas).

PubMed

Dalleau, Mayeul; Ciccione, Stéphane; Mortimer, Jeanne A; Garnier, Julie; Benhamou, Simon; Bourjea, Jérôme

2012-01-01

Changes in phenology, the timing of seasonal activities, are among the most frequently observed responses to environmental disturbances and in marine species are known to occur in response to climate changes that directly affects ocean temperature, biogeochemical composition and sea level. We examined nesting seasonality data from long-term studies at 8 green turtle (Chelonia mydas) rookeries that include 21 specific nesting sites in the South-West Indian Ocean (SWIO). We demonstrated that temperature drives patterns of nesting seasonality at the regional scale. We found a significant correlation between mean annual Sea Surface Temperature (SST) and dates of peak nesting with rookeries exposed to higher SST having a delayed nesting peak. This supports the hypothesis that temperature is the main factor determining peak nesting dates. We also demonstrated a spatial synchrony in nesting activity amongst multiple rookeries in the northern part of the SWIO (Aldabra, Glorieuses, Mohéli, Mayotte) but not with the eastern and southern rookeries (Europa, Tromelin), differences which could be attributed to females with sharply different adult foraging conditions. However, we did not detect a temporal trend in the nesting peak date over the study period or an inter-annual relation between nesting peak date and SST. The findings of our study provide a better understanding of the processes that drive marine species phenology. The findings will also help to predict their ability to cope with climate change and other environmental perturbations. Despite demonstrating this spatial shift in nesting phenology, no trend in the alteration of nesting dates over more than 20 years was found.

Nesting Phenology of Marine Turtles: Insights from a Regional Comparative Analysis on Green Turtle (Chelonia mydas)

PubMed Central

Dalleau, Mayeul; Ciccione, Stéphane; Mortimer, Jeanne A.; Garnier, Julie; Benhamou, Simon; Bourjea, Jérôme

2012-01-01

Changes in phenology, the timing of seasonal activities, are among the most frequently observed responses to environmental disturbances and in marine species are known to occur in response to climate changes that directly affects ocean temperature, biogeochemical composition and sea level. We examined nesting seasonality data from long-term studies at 8 green turtle (Chelonia mydas) rookeries that include 21 specific nesting sites in the South-West Indian Ocean (SWIO). We demonstrated that temperature drives patterns of nesting seasonality at the regional scale. We found a significant correlation between mean annual Sea Surface Temperature (SST) and dates of peak nesting with rookeries exposed to higher SST having a delayed nesting peak. This supports the hypothesis that temperature is the main factor determining peak nesting dates. We also demonstrated a spatial synchrony in nesting activity amongst multiple rookeries in the northern part of the SWIO (Aldabra, Glorieuses, Mohéli, Mayotte) but not with the eastern and southern rookeries (Europa, Tromelin), differences which could be attributed to females with sharply different adult foraging conditions. However, we did not detect a temporal trend in the nesting peak date over the study period or an inter-annual relation between nesting peak date and SST. The findings of our study provide a better understanding of the processes that drive marine species phenology. The findings will also help to predict their ability to cope with climate change and other environmental perturbations. Despite demonstrating this spatial shift in nesting phenology, no trend in the alteration of nesting dates over more than 20 years was found. PMID:23056527

Using Satellite Tracking to Optimize Protection of Long-Lived Marine Species: Olive Ridley Sea Turtle Conservation in Central Africa

PubMed Central

Maxwell, Sara M.; Breed, Greg A.; Nickel, Barry A.; Makanga-Bahouna, Junior; Pemo-Makaya, Edgard; Parnell, Richard J.; Formia, Angela; Ngouessono, Solange; Godley, Brendan J.; Costa, Daniel P.; Witt, Matthew J.; Coyne, Michael S.

2011-01-01

Tractable conservation measures for long-lived species require the intersection between protection of biologically relevant life history stages and a socioeconomically feasible setting. To protect breeding adults, we require knowledge of animal movements, how movement relates to political boundaries, and our confidence in spatial analyses of movement. We used satellite tracking and a switching state-space model to determine the internesting movements of olive ridley sea turtles (Lepidochelys olivacea) (n = 18) in Central Africa during two breeding seasons (2007-08, 2008-09). These movements were analyzed in relation to current park boundaries and a proposed transboundary park between Gabon and the Republic of Congo, both created to reduce unintentional bycatch of sea turtles in marine fisheries. We additionally determined confidence intervals surrounding home range calculations. Turtles remained largely within a 30 km radius from the original nesting site before departing for distant foraging grounds. Only 44.6 percent of high-density areas were found within the current park but the proposed transboundary park would incorporate 97.6 percent of high-density areas. Though tagged individuals originated in Gabon, turtles were found in Congolese waters during greater than half of the internesting period (53.7 percent), highlighting the need for international cooperation and offering scientific support for a proposed transboundary park. This is the first comprehensive study on the internesting movements of solitary nesting olive ridley sea turtles, and it suggests the opportunity for tractable conservation measures for female nesting olive ridleys at this and other solitary nesting sites around the world. We draw from our results a framework for cost-effective protection of long-lived species using satellite telemetry as a primary tool. PMID:21589942

Migrations of Green Turtles (Chelonia mydas) between Nesting and Foraging Grounds across the Coral Sea

PubMed Central

Read, Tyffen C.; Wantiez, Laurent; Werry, Jonathan M.; Farman, Richard; Petro, George; Limpus, Colin J.

2014-01-01

Marine megafauna tend to migrate vast distances, often crossing national borders and pose a significant challenge to managers. This challenge is particularly acute in the Pacific, which contains numerous small island nations and thousands of kilometers of continental margins. The green sea turtle, Chelonia mydas, is one such megafauna that is endangered in Pacific waters due to the overexploitation of eggs and adults for human consumption. Data from long-term tagging programs in Queensland (Australia) and New Caledonia were analysed to investigate the migrations by C. mydas across the Coral Sea between their nesting site and their feeding grounds. A review of data collected over the last 50 years by different projects identified multiple migrations of C. mydas to and from New Caledonia (n = 97) and indicate that turtles foraging in New Caledonia nest in the Great Barrier Reef (Australia) and vice versa. Several explanations exist for turtles exhibiting this energetically costly movement pattern from breeding to distant foraging grounds (1200–2680 km away) despite viable foraging habitat being available in the local vicinity. These include hatchling drift, oceanic movements and food abundance predictability. Most of the tag recoveries in New Caledonia belonged to females from the south Great Barrier Reef genetic stock. Some females (n = 2) even showed fidelity to foraging sites located 1200 km away from the nesting site located in New Caledonia. This study also reveals previously unknown migrations pathways of turtles within the Coral Sea. PMID:24940598

Migrations of green turtles (Chelonia mydas) between nesting and foraging grounds across the Coral Sea.

PubMed

Read, Tyffen C; Wantiez, Laurent; Werry, Jonathan M; Farman, Richard; Petro, George; Limpus, Colin J

2014-01-01

Marine megafauna tend to migrate vast distances, often crossing national borders and pose a significant challenge to managers. This challenge is particularly acute in the Pacific, which contains numerous small island nations and thousands of kilometers of continental margins. The green sea turtle, Chelonia mydas, is one such megafauna that is endangered in Pacific waters due to the overexploitation of eggs and adults for human consumption. Data from long-term tagging programs in Queensland (Australia) and New Caledonia were analysed to investigate the migrations by C. mydas across the Coral Sea between their nesting site and their feeding grounds. A review of data collected over the last 50 years by different projects identified multiple migrations of C. mydas to and from New Caledonia (n = 97) and indicate that turtles foraging in New Caledonia nest in the Great Barrier Reef (Australia) and vice versa. Several explanations exist for turtles exhibiting this energetically costly movement pattern from breeding to distant foraging grounds (1200-2680 km away) despite viable foraging habitat being available in the local vicinity. These include hatchling drift, oceanic movements and food abundance predictability. Most of the tag recoveries in New Caledonia belonged to females from the south Great Barrier Reef genetic stock. Some females (n = 2) even showed fidelity to foraging sites located 1200 km away from the nesting site located in New Caledonia. This study also reveals previously unknown migrations pathways of turtles within the Coral Sea.

Using expert opinion surveys to rank threats to endangered species: a case study with sea turtles.

PubMed

Donlan, C Josh; Wingfield, Dana K; Crowder, Larry B; Wilcox, Chris

2010-12-01

Little is known about how specific anthropogenic hazards affect the biology of organisms. Quantifying the effect of regional hazards is particularly challenging for species such as sea turtles because they are migratory, difficult to study, long lived, and face multiple anthropogenic threats. Expert elicitation, a technique used to synthesize opinions of experts while assessing uncertainty around those views, has been in use for several decades in the social science and risk assessment sectors. We conducted an internet-based survey to quantify expert opinion on the relative magnitude of anthropogenic hazards to sea turtle populations at the regional level. Fisheries bycatch and coastal development were most often ranked as the top hazards to sea turtle species in a geographic region. Nest predation and direct take followed as the second and third greatest threats, respectively. Survey results suggest most experts believe sea turtles are threatened by multiple factors, including substantial at-sea threats such as fisheries bycatch. Resources invested by the sea turtle community, however, appear biased toward terrestrial-based impacts. Results from the survey are useful for conservation planning because they provide estimates of relative impacts of hazards on sea turtles and a measure of consensus on the magnitude of those impacts among researchers and practitioners. Our survey results also revealed patterns of expert bias, which we controlled for in our analysis. Respondents with no experience with respect to a sea turtle species tended to rank hazards affecting that sea turtle species higher than respondents with experience. A more-striking pattern was with hazard-based expertise: the more experience a respondent had with a specific hazard, the higher the respondent scored the impact of that hazard on sea turtle populations. Bias-controlled expert opinion surveys focused on threatened species and their hazards can help guide and expedite species recovery plans. © 2010 Society for Conservation Biology.

Life history and environmental requirements of loggerhead turtles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, D.A.

1988-08-01

In the United States scattered nestings of loggerhead sea turtles (Caretta caretta) may occur in most of its range from Texas to Florida and Florida to New Jersey; however, nesting concentrations occur on coastal islands of North Carolina, South Carolina, and Georgia and on the coasts of Florida. The greatest portion of a loggerhead's life is spent in ocean and estuarine waters where it breeds in shallow waters adjacent to nesting beaches, feeds on a variety of fish and shellfish, and migrates generally north in the spring and summer and south in the fall and winter. The other part ofmore » its life is spent on coastal beaches where the female digs a nest, lays her eggs (average 120 eggs), the eggs hatch (in 46 to 65 days), and the hatchlings emerge from the nest as a group and orient seaward to become part of the aquatic system again. Nesting activity begins in the spring, peaks in midsummer, and declines until completion in late summer. A loggerhead female generally nests every other or every third year. Beach sand temperatures may affect nest site selection by females, the incubation time and hatching success of eggs, and the sex and emergence timing of hatchlings. Most management of sea turtles has been directed toward increasing hatching and hatchling success through predator control, egg relocation, and raising captive hatchlings. 183 refs.; 10 figs.; 3 tabs.« less

Metals in Blood and Eggs of Green Sea Turtles (Chelonia mydas) from Nesting Colonies of the Northern Coast of the Sea of Oman.

PubMed

Sinaei, Mahmood; Bolouki, Mehdi

2017-11-01

The green sea turtle (Chelonia mydas) has been a species of global concern for decades. In this study, heavy metals (mercury: Hg; Cadmium: Cd; Lead: Pb; Copper: Cu; and Zinc: Zn) were measured in blood and three egg fraction of green sea turtles nesting on the northern coast of Sea of Oman. Heavy metals concentrations in blood, yolk, albumen, and egg shell ranged between 0.16-36.78, 0.006-33.88, 0.003-4.02, and 0.002-6.85 μg/g (ww), respectively. According to the results, all heavy metals found in blood samples (n = 12) also were detected in the various parts of the eggs (n = 48). Moreover, there were no significant differences between concentrations of heavy metals in different clutches laid in a nesting season. However, Pb concentrations in blood samples significantly increased in later clutches (p < 0.05), whereas Cu concentrations in blood samples exhibit a declining trend (p < 0.05). These results reveal the existence of maternal transfer phenomenon in green sea turtles on the northern coast of Sea of Oman. Results of this study suggest that heavy metals could be one of the factors influencing reductions in fertilization and hatching success. Results also indicate that green sea turtle on the northern coast of Sea of Oman have high capacity in rapid response and detoxification of heavy metals and/or from the low exposure levels of these turtles to the heavy metals. Further research is required concerning the effects of heavy metals on green sea turtles, especially on their possible influence of fetal development of turtles.

Toxic elements and associations with hematology, plasma biochemistry, and protein electrophoresis in nesting loggerhead sea turtles (Caretta caretta) from Casey Key, Florida.

PubMed

Perrault, Justin R; Stacy, Nicole I; Lehner, Andreas F; Poor, Savannah K; Buchweitz, John P; Walsh, Catherine J

2017-12-01

Toxic elements (arsenic, cadmium, lead, mercury, selenium, thallium) are a group of contaminants that are known to elicit developmental, reproductive, general health, and immune system effects in reptiles, even at low concentrations. Reptiles, including marine turtles, are susceptible to accumulation of toxic elements due to their long life span, low metabolic rate, and highly efficient conversion of prey into biomass. The objectives of this study were to (1) document concentrations of arsenic, cadmium, lead, mercury, selenium, and thallium in whole blood and keratin from nesting loggerhead sea turtles (Caretta caretta) from Casey Key, Florida and document correlations thereof and (2) correlate whole blood toxic element concentrations to various hematological and plasma biochemistry analytes. Baselines for various hematological and plasma analytes and toxic elements in whole blood and keratin (i.e., scute) in nesting loggerheads are documented. Various correlations between the toxic elements and hematological and plasma biochemistry analytes were identified; however, the most intriguing were negative correlations between arsenic, cadmium, lead, and selenium with and α- and γ-globulins. Although various extrinsic and intrinsic variables such as dietary and feeding changes in nesting loggerheads need to be considered, this finding may suggest a link to altered humoral immunity. This study documents a suite of health variables of nesting loggerheads in correlation to contaminants and identifies the potential of toxic elements to impact the overall health of nesting turtles, thus presenting important implications for the conservation and management of this species. Copyright © 2017 Elsevier Ltd. All rights reserved.

Critically evaluating best management practices for preventing freshwater turtle extinctions.

PubMed

Spencer, R-J; Van Dyke, J U; Thompson, Michael B

2017-12-01

Ex situ conservation tools, such as captive breeding for reintroduction, are considered a last resort to recover threatened or endangered species, but they may also help reduce anthropogenic threats where it is difficult or impossible to address them directly. Headstarting, or captive rearing of eggs or neonate animals for subsequent release into the wild, is controversial because it treats only a symptom of a larger conservation problem; however, it may provide a mechanism to address multiple threats, particularly near population centers. We conducted a population viability analysis of Australia's most widespread freshwater turtle, Chelodina longicollis, to determine the effect of adult roadkill (death by collision with motor vehicles), which is increasing, and reduced recruitment through nest predation from introduced European red foxes (Vulpes vulpes). We also modeled management scenarios to test the effectiveness of headstarting, fox management, and measures to reduce mortality on roads. Only scenarios with headstarting from source populations eliminated all risks of extinction and allowed population growth. Small increases in adult mortality (2%) had the greatest effect on population growth and extinction risk. Where threats simultaneously affected other life-history stages (e.g., recruitment), eliminating harvest pressures on adult females alone did not eliminate the risk of population extinction. In our models, one source population could supply enough hatchlings annually to supplement 25 other similar-sized populations such that extinction was avoided. Based on our results, we believe headstarting should be a primary tool for managing freshwater turtles for which threats affect multiple life-history stages. We advocate the creation of source populations for managing freshwater turtles that are greatly threatened at multiple life-history stages, such as depredation of eggs by invasive species and adult mortality via roadkill. © 2017 Society for Conservation Biology.

A comparison of diel nest temperature and nest site selection for two sympatric species of freshwater turtles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bodie, J.R.; Burke, V.J.; Smith, K.R.

1996-07-01

Diel nest temperature profiles were recorded form natural nests of eastern mud turtles (Kinosternon subrubrum) and Florida cooters (Pseudemys floridana) to determine whether nest microhabitat selection compensates for the effect of interspecific differences in nest depth on nest temperature. Kinosternon subrubrum nest depths were significantly shallower than those of P. floridana (t = 2.93, P < 0.01). We predicted that differences in nest depth would result in K. subrubrum nests being cooler at night and warmer during daylight than the deeper P. floridana nests. Diel temperature patterns agreed with out predictions at night, but P. floridana nest temperatures were notmore » lower than K. subrubrum nest temperatures during the day. Soil composition, slope and soil moisture were similar for the nest of both species. However, the amount of sunlight reaching the soil above K. subrubrum nest sites was substantially less than the amount above P. floridana nest sites. We suggest that these species select habitats for oviposition that differ in the amount and types of vegetative cover, which in turn affect exposure to sunlight and ultimately nest temperature. 27 refs., 2 figs.« less

Increased expression of Hsp70 and Hsp90 mRNA as biomarkers of thermal stress in loggerhead turtle embryos (Caretta Caretta).

PubMed

Tedeschi, J N; Kennington, W J; Berry, O; Whiting, S; Meekan, M; Mitchell, N J

2015-01-01

The survival and viability of sea turtle embryos is dependent upon favourable nest temperatures throughout the incubation period. Consequently, future generations of sea turtles may be at risk from increasing nest temperatures due to climate change, but little is known about how embryos respond to heat stress. Heat shock genes are likely to be important in this process because they code for proteins that prevent cellular damage in response to environmental stressors. This study provides the first evidence of an expression response in the heat shock genes of embryos of loggerhead sea turtles (Caretta caretta) exposed to realistic and near-lethal temperatures (34°C and 36°C) for 1 or 3 hours. We investigated changes in Heat shock protein 60 (Hsp60), Hsp70, and Hsp90 mRNA in heart (n=24) and brain tissue (n=29) in response to heat stress. Under the most extreme treatment (36°C, 3h), Hsp70 increased mRNA expression by a factor of 38.8 in heart tissue and 15.7 in brain tissue, while Hsp90 mRNA expression increased by a factor of 98.3 in heart tissue and 14.7 in brain tissue. Hence, both Hsp70 and Hsp90 are useful biomarkers for assessing heat stress in the late-stage embryos of sea turtles. The method we developed can be used as a platform for future studies on variation in the thermotolerance response from the clutch to population scale, and can help us anticipate the resilience of reptile embryos to extreme heating events. Copyright © 2014 Elsevier Ltd. All rights reserved.

Identification of wood turtle nesting areas for protection and management

Treesearch

Richard R. Buech; Lynelle G. Hanson; Mark D. Nelson

1997-01-01

The wood turtle, Clemmys insculpta, is a long-lived, semi-aquatic, riverine species that inhabits forested regions of the northcentral and northeastern United States and adjacent regions of Canada. Many states list the wood turtle as "Endangered" or "Threatened" and it is now listed on Appendix II of the Convention on...

Learning from Experience: A Report from Mexico's Turtle Trip 2000.

ERIC Educational Resources Information Center

Jankowska, Marta Maja

2000-01-01

Fifteen high school students and adults from Idaho traveled to Mexico to assist the One World Workforce with monitoring the nests of olive ridley sea turtles. Only 1 percent of these endangered turtles mature to adulthood. The volunteers protected the eggs from poachers and helped the hatchlings get safely to the water. (TD)

Coastal leatherback turtles reveal conservation hotspot

PubMed Central

Robinson, Nathan J.; Morreale, Stephen J.; Nel, Ronel; Paladino, Frank V.

2016-01-01

Previous studies have shown that the world’s largest reptile – the leatherback turtle Dermochelys coriacea – conducts flexible foraging migrations that can cover thousands of kilometres between nesting sites and distant foraging areas. The vast distances that may be travelled by migrating leatherback turtles have greatly complicated conservation efforts for this species worldwide. However, we demonstrate, using a combination of satellite telemetry and stable isotope analysis, that approximately half of the nesting leatherbacks from an important rookery in South Africa do not migrate to distant foraging areas, but rather, forage in the coastal waters of the nearby Mozambique Channel. Moreover, this coastal cohort appears to remain resident year-round in shallow waters (<50 m depth) in a relatively fixed area. Stable isotope analyses further indicate that the Mozambique Channel also hosts large numbers of loggerhead turtles Caretta caretta. The rare presence of a resident coastal aggregation of leatherback turtles not only presents a unique opportunity for conservation, but alongside the presence of loggerhead turtles and other endangered marine megafauna in the Mozambique Channel, highlights the importance of this area as a marine biodiversity hotspot. PMID:27886262

Plasma Cholinesterase Activity in Female Green Turtles Chelonia mydas Nesting in Laguna de Terminos, Mexico Related to Organochlorine Pesticides in Their Eggs.

PubMed

Rivas-Hernández, Gerardo; May-Uc, Yaneli; Noreña-Barroso, Elsa; Cobos-Gasca, Víctor; Rodríguez-Fuentes, Gabriela

2018-01-01

The inhibition of cholinesterase (ChE) activity has been used as a biomarker of exposure to organophosphate and carbamate insecticides. ChE of nesting female green turtles (Chelonia mydas) were biochemically characterized using two substrates, acetylthiocholine iodide and butyrylthiocholine iodide, and three ChE inhibitors (eserine sulfate, BW284C51 and iso-OMPA). The results indicated that BChE is the predominant plasma ChE in female C. mydas, but with atypical properties that differ from those found in human BChE. Eggs from green turtles nesting at two sites in Laguna de Terminos contained µg g -1 (wet weight) quantities of organochlorine (OC) pesticides. Drins (aldrin, dieldrin, endrin, endrin ketone, endrin aldehyde) were found at the highest concentrations with no significant differences in the concentrations in eggs collected at the two sampling sites. A negative relationship was found between levels of OC pesticides in eggs and BChE activity in the plasma of female turtles laying the eggs. Since OC pesticides are not cholinesterase inhibitors, we hypothesized that this inverse relationship may be related to an antagonistic effect between OCs and organophosphate pesticides and mobilization of OCs from the fatty tissues of the female turtles into their eggs. However, further study is required to verify the hypothesis. It is also possible that other contaminants, such as petroleum hydrocarbons are responsible for the modulation of cholinesterase activity in female turtles.

Beyond harm’s reach? Submersion of river turtle nesting areas and implications for restoration actions after Amazon hydropower development

PubMed Central

Michalski, Fernanda; Gibbs, James P.

2018-01-01

The global expansion of energy demands combined with abundant rainfall, large water volumes and high flow in tropical rivers have led to an unprecedented expansion of dam constructions in the Amazon. This expansion generates an urgent need for refined approaches to river management; specifically a move away from decision-making governed by overly generalized guidelines. For the first time we quantify direct impacts of hydropower reservoir establishment on an Amazon fresh water turtle. We conducted surveys along 150 km of rivers upstream of a new dam construction during the low water months that correspond to the nesting season of Podocnemis unifilis in the study area. Comparison of nest-areas before (2011, 2015) and after (2016) reservoir filling show that reservoir impacts extend 13% beyond legally defined limits. The submerged nesting areas accounted for a total of 3.8 ha of nesting habitat that was inundated as a direct result of the reservoir filling in 2016. Our findings highlight limitations in the development and implementation of existing Brazilian environmental impact assessment process. We also propose potential ways to mitigate the negative impacts of dams on freshwater turtles and the Amazonian freshwater ecosystems they inhabit. PMID:29333347

Beyond harm's reach? Submersion of river turtle nesting areas and implications for restoration actions after Amazon hydropower development.

PubMed

Norris, Darren; Michalski, Fernanda; Gibbs, James P

2018-01-01

The global expansion of energy demands combined with abundant rainfall, large water volumes and high flow in tropical rivers have led to an unprecedented expansion of dam constructions in the Amazon. This expansion generates an urgent need for refined approaches to river management; specifically a move away from decision-making governed by overly generalized guidelines. For the first time we quantify direct impacts of hydropower reservoir establishment on an Amazon fresh water turtle. We conducted surveys along 150 km of rivers upstream of a new dam construction during the low water months that correspond to the nesting season of Podocnemis unifilis in the study area. Comparison of nest-areas before (2011, 2015) and after (2016) reservoir filling show that reservoir impacts extend 13% beyond legally defined limits. The submerged nesting areas accounted for a total of 3.8 ha of nesting habitat that was inundated as a direct result of the reservoir filling in 2016. Our findings highlight limitations in the development and implementation of existing Brazilian environmental impact assessment process. We also propose potential ways to mitigate the negative impacts of dams on freshwater turtles and the Amazonian freshwater ecosystems they inhabit.

Ontogenetic development of migration: Lagrangian drift trajectories suggest a new paradigm for sea turtles.

PubMed

Hays, Graeme C; Fossette, Sabrina; Katselidis, Kostas A; Mariani, Patrizio; Schofield, Gail

2010-09-06

Long distance migration occurs in a wide variety of taxa including birds, insects, fishes, mammals and reptiles. Here, we provide evidence for a new paradigm for the determinants of migration destination. As adults, sea turtles show fidelity to their natal nesting areas and then at the end of the breeding season may migrate to distant foraging sites. For a major rookery in the Mediterranean, we simulated hatchling drift by releasing 288 000 numerical particles in an area close to the nesting beaches. We show that the pattern of adult dispersion from the breeding area reflects the extent of passive dispersion that would be experienced by hatchlings. Hence, the prevailing oceanography around nesting areas may be crucial to the selection of foraging sites used by adult sea turtles. This environmental forcing may allow the rapid evolution of new migration destinations if ocean currents alter with climate change.

Ontogenetic development of migration: Lagrangian drift trajectories suggest a new paradigm for sea turtles

PubMed Central

Hays, Graeme C.; Fossette, Sabrina; Katselidis, Kostas A.; Mariani, Patrizio; Schofield, Gail

2010-01-01

Long distance migration occurs in a wide variety of taxa including birds, insects, fishes, mammals and reptiles. Here, we provide evidence for a new paradigm for the determinants of migration destination. As adults, sea turtles show fidelity to their natal nesting areas and then at the end of the breeding season may migrate to distant foraging sites. For a major rookery in the Mediterranean, we simulated hatchling drift by releasing 288 000 numerical particles in an area close to the nesting beaches. We show that the pattern of adult dispersion from the breeding area reflects the extent of passive dispersion that would be experienced by hatchlings. Hence, the prevailing oceanography around nesting areas may be crucial to the selection of foraging sites used by adult sea turtles. This environmental forcing may allow the rapid evolution of new migration destinations if ocean currents alter with climate change. PMID:20236958

Does behaviour affect the dispersal of flatback post-hatchlings in the Great Barrier Reef?

PubMed Central

Critchell, Kay; Fuentes, Mariana M. P. B.; Limpus, Colin J.; Wolanski, Eric; Hamann, Mark

2017-01-01

The ability of individuals to actively control their movements, especially during the early life stages, can significantly influence the distribution of their population. Most marine turtle species develop oceanic foraging habitats during different life stages. However, flatback turtles (Natator depressus) are endemic to Australia and are the only marine turtle species with an exclusive neritic development. To explain the lack of oceanic dispersal of this species, we predicted the dispersal of post-hatchlings in the Great Barrier Reef (GBR), Australia, using oceanographic advection-dispersal models. We included directional swimming in our models and calibrated them against the observed distribution of post-hatchling and adult turtles. We simulated the dispersal of green and loggerhead turtles since they also breed in the same region. Our study suggests that the neritic distribution of flatback post-hatchlings is favoured by the inshore distribution of nesting beaches, the local water circulation and directional swimming during their early dispersal. This combination of factors is important because, under the conditions tested, if flatback post-hatchlings were entirely passively transported, they would be advected into oceanic habitats after 40 days. Our results reinforce the importance of oceanography and directional swimming in the early life stages and their influence on the distribution of a marine turtle species. PMID:28573024

First approximation to congenital malformation rates in embryos and hatchlings of sea turtles.

PubMed

Bárcenas-Ibarra, Annelisse; de la Cueva, Horacio; Rojas-Lleonart, Isaias; Abreu-Grobois, F Alberto; Lozano-Guzmán, Rogelio Iván; Cuevas, Eduardo; García-Gasca, Alejandra

2015-03-01

Congenital malformations in sea turtles have been considered sporadical. Research carried out in the Mexican Pacific revealed high levels of congenital malformations in the olive ridley, but little or no information is available for other species. We present results from analyses of external congenital malformations in olive ridley, green, and hawskbill sea turtles from Mexican rookeries on the Pacific coast and Gulf of Mexico. We examined 150 green and hawksbill nests and 209 olive ridley nests during the 2010 and 2012 nesting seasons, respectively. Olive ridley eggs were transferred to a hatchery and incubated in styrofoam boxes. Nests from the other two species were left in situ. Number of eggs, live and dead hatchlings, and eggs with or without embryonic development were registered. Malformation frequency was evaluated with indices of prevalence and severity. Mortality levels, prevalence and severity were higher in olive ridley than in hawksbill and green sea turtles. Sixty-three types of congenital malformations were observed in embryos, and dead or live hatchlings. Of these, 38 are new reports; 35 for wild sea turtles, three for vertebrates. Thirty-one types were found in hawksbill, 23 in green, and 59 in olive ridley. The head region showed a higher number of malformation types. Malformation levels in the olive ridley were higher than previously reported. Olive ridleys seem more prone to the occurrence of congenital malformations than the other two species. Whether the observed malformation levels are normal or represent a health problem cannot be currently ascertained without long-term assessments. © 2015 Wiley Periodicals, Inc.

A mechanism that maintains alternative life histories in a loggerhead sea turtle population.

PubMed

Hatase, Hideo; Omuta, Kazuyoshi; Tsukamoto, Katsumi

2013-11-01

Intrapopulation variation in habitat use is commonly seen among mobile animals, yet the mechanisms maintaining it have rarely been researched among untrackable species. To investigate how alternative life histories are maintained in a population of the loggerhead sea turtle (Caretta caretta), cumulative reproductive output was evaluated and compared between small planktivores inhabiting oceanic areas (with water depths > 200 m) and large benthivores inhabiting neritic areas (depths < 200 m) that sympatrically nested at Yakushima Island, Japan, from 1986 to 2011. In total, 362 nesting females sampled in three different years were classified into the two foraging groups based on stable isotope ratios in egg yolks. There were significant differences between the two foraging groups in most recorded life history parameters (clutch size, clutch frequency, breeding frequency, and remigration intervals), with the exception of emergence success. We did not find evidence of life history trade-offs, nor age-related changes in fecundity. Over the 26-year study period, we calculated a 2.4-fold greater reproductive output for neritic foragers than for oceanic ones, accounting for breeding and clutch frequency. Temporal consistencies in stable isotope ratios and remigration intervals within females suggested that female Japanese loggerheads show fidelity to respective foraging habitats throughout the adult stage. The large difference in productivity between the two groups was unlikely to be offset by the difference in survival during the period from aboveground emergence to first reproduction, suggesting that oceanic foragers have a lower level of fitness than neritic ones. Together with an absence of genetic structure between foraging groups, we infer that alternative life histories in a loggerhead turtle population are maintained by a conditional strategy.

Seasonal change in the capacity for supercooling by neonatal painted turtles.

PubMed

Packard, G C; Packard, M J; McDaniel, L L

2001-05-01

Hatchlings of the North American painted turtle (Chrysemys picta) typically spend their first winter of life inside the shallow, subterranean nest where they completed incubation the preceding summer. This facet of their natural history commonly causes neonates in northerly populations to be exposed in mid-winter to ice and cold, which many animals survive by remaining unfrozen and supercooled. We measured the limit of supercooling in samples of turtles taken shortly after hatching and in other samples after 2 months of acclimation (or acclimatization) to a reduced temperature in the laboratory or field. Animals initially had only a limited capacity for supercooling, but they acquired an ability to undergo deeper supercooling during the course of acclimation. The gut of most turtles was packed with particles of soil and eggshell shortly after hatching, but not after acclimation. Thus, the relatively high limit of supercooling for turtles in the days immediately after hatching may have resulted from the ingestion of soil (and associated nucleating agents) by the animals as they were freeing themselves from their eggshell, whereas the relatively low limit of supercooling attained by acclimated turtles may have resulted from their purging their gut of its contents. Parallels may, therefore, exist between the natural-history strategy expressed by hatchling painted turtles and that expressed by numerous terrestrial arthropods that withstand the cold of winter by sustaining a state of supercooling.

The case for long range chemoreceptive piloting in Chelonia

NASA Technical Reports Server (NTRS)

Carr, A. F., Jr.

1972-01-01

The reproductive ecology and migration habits of Chelonia are investigated. Efforts were made to determine if the turtle navigates by chemoreception and if sensory responses of the migrating animals could be electronically tracked through telemetry. Efforts were also made to: (1) explain why certain small islands or restricted areas of mainland shore are chosen by Chelonia as nesting grounds, even when located a thousand miles or more from the year round feeding grounds of the population; (2) identify guidance mechanisms used by migrants in their periodic open ocean travels; and (3) account for the so called lost year - the virtually complete disappearance of young sea turtles during their first year of life. It was suggested that turtle migration is aided by an olfactory mechanism, sun compass, and ocean currents. The tracking experiment was unsuccessful; the equipment was lost or damaged and stopped functioning after about two hours.

Physiological ecology of overwintering in the hatchling painted turtle: multiple-scale variation in response to environmental stress.

PubMed

Costanzo, Jon P; Dinkelacker, Stephen A; Iverson, John B; Lee, Richard E

2004-01-01

We integrated field and laboratory studies in an investigation of water balance, energy use, and mechanisms of cold-hardiness in hatchling painted turtles (Chrysemys picta) indigenous to west-central Nebraska (Chrysemys picta bellii) and northern Indiana (Chrysemys picta marginata) during the winters of 1999-2000 and 2000-2001. We examined 184 nests, 80 of which provided the hatchlings (n=580) and/or samples of soil used in laboratory analyses. Whereas winter 1999-2000 was relatively dry and mild, the following winter was wet and cold; serendipitously, the contrast illuminated a marked plasticity in physiological response to environmental stress. Physiological and cold-hardiness responses of turtles also varied between study locales, largely owing to differences in precipitation and edaphics and the lower prevailing and minimum nest temperatures (to -13.2 degrees C) encountered by Nebraska turtles. In Nebraska, winter mortality occurred within 12.5% (1999-2000) and 42.3% (2000-2001) of the sampled nests; no turtles died in the Indiana nests. Laboratory studies of the mechanisms of cold-hardiness used by hatchling C. picta showed that resistance to inoculative freezing and capacity for freeze tolerance increased as winter approached. However, the level of inoculation resistance strongly depended on the physical characteristics of nest soil, as well as its moisture content, which varied seasonally. Risk of inoculative freezing (and mortality) was greatest in midwinter when nest temperatures were lowest and soil moisture and activity of constituent organic ice nuclei were highest. Water balance in overwintering hatchlings was closely linked to dynamics of precipitation and soil moisture, whereas energy use and the size of the energy reserve available to hatchlings in spring depended on the winter thermal regime. Acute chilling resulted in hyperglycemia and hyperlactemia, which persisted throughout winter; this response may be cryoprotective. Some physiological characteristics and cold-hardiness attributes varied between years, between study sites, among nests at the same site, and among siblings sharing nests. Such variation may reflect adaptive phenotypic plasticity, maternal or paternal influence on an individual's response to environmental challenge, or a combination of these factors. Some evidence suggests that life-history traits, such as clutch size and body size, have been shaped by constraints imposed by the harsh winter environment.

Migratory corridors of adult female Kemp’s ridley turtles in the Gulf of Mexico

USGS Publications Warehouse

Shaver, Donna J.; Hart, Kristen M.; Fujisaki, Ikuko; Rubio, Cynthia; Sartain-Iverson, Autumn R.; Pena, Jaime; Gamez, Daniel Gomez; Gonzales Diaz Miron, Raul de Jesus; Burchfield, Patrick M.; Martinez, Hector J.; Ortiz, Jaime

2016-01-01

For many marine species, locations of migratory pathways are not well defined. We used satellite telemetry and switching state-space modeling (SSM) to define the migratory corridor used by Kemp's ridley turtles (Lepidochelys kempii) in the Gulf of Mexico. The turtles were tagged after nesting at Padre Island National Seashore, Texas, USA from 1997 to 2014 (PAIS; n = 80); Rancho Nuevo, Tamaulipas, Mexico from 2010 to 2011 (RN; n = 14); Tecolutla, Veracruz, Mexico from 2012 to 2013 (VC; n = 13); and Gulf Shores, Alabama, USA during 2012 (GS; n = 1). The migratory corridor lies in nearshore Gulf of Mexico waters in the USA and Mexico with mean water depth of 26 m and a mean distance of 20 km from the nearest mainland coast. Migration from the nesting beach is a short phenomenon that occurs from late-May through August, with a peak in June. There was spatial similarity of post-nesting migratory pathways for different turtles over a 16 year period. Thus, our results indicate that these nearshore Gulf waters represent a critical migratory habitat for this species. However, there is a gap in our understanding of the migratory pathways used by this and other species to return from foraging grounds to nesting beaches. Therefore, our results highlight the need for tracking reproductive individuals from foraging grounds to nesting beaches. Continued tracking of adult females from PAIS, RN, and VC nesting beaches will allow further study of environmental and bathymetric components of migratory habitat and threats occurring within our defined corridor. Furthermore, the existence of this migratory corridor in nearshore waters of both the USA and Mexico demonstrates that international cooperation is necessary to protect essential migratory habitat for this imperiled species.

Philopatry of male marine turtles inferred from mitochondrial DNA markers

PubMed Central

FitzSimmons, Nancy N.; Limpus, Colin J.; Norman, Janette A.; Goldizen, Alan R.; Miller, Jeffrey D.; Moritz, Craig

1997-01-01

Recent studies of mitochondrial DNA (mtDNA) variation among marine turtle populations are consistent with the hypothesis that females return to beaches in their natal region to nest as adults. In contrast, less is known about breeding migrations of male marine turtles and whether they too are philopatric to natal regions. Studies of geographic structuring of restriction fragment and microsatellite polymorphisms at anonymous nuclear loci in green turtle (Chelonia mydas) populations indicate that nuclear gene flow is higher than estimates from mtDNA analyses. Regional populations from the northern and southern Great Barrier Reef were distinct for mtDNA but indistinguishable at nuclear loci, whereas the Gulf of Carpentaria (northern Australia) population was distinct for both types of marker. To assess whether this result was due to reduced philopatry of males across the Great Barrier Reef, we determined the mtDNA haplotypes of breeding males at courtship areas for comparison with breeding females from the same three locations. We used a PCR-restriction fragment length polymorphism approach to determine control region haplotypes and designed mismatch primers for the identification of specific haplotypes. The mtDNA haplotype frequencies were not significantly different between males and females at any of the three areas and estimates of Fst among the regions were similar for males and females (Fst = 0.78 and 0.73, respectively). We conclude that breeding males, like females, are philopatric to courtship areas within their natal region. Nuclear gene flow between populations is most likely occurring through matings during migrations of both males and females through nonnatal courtship areas. PMID:9238077

Phylogeography of colonially nesting seabirds, with special reference to global matrilineal patterns in the sooty tern (Sterna fuscata).

PubMed

Avise, J C; Nelson, W S; Bowen, B W; Walker, D

2000-11-01

Sooty tern (Sterna fuscata) rookeries are scattered throughout the tropical oceans. When not nesting, individuals wander great distances across open seas, but, like many other seabirds, they tend to be site-faithful to nesting locales in successive years. Here we examine the matrilineal history of sooty terns on a global scale. Assayed colonies within an ocean are poorly differentiated in mitochondrial DNA sequence, a result indicating tight historical ties. However, a shallow genealogical partition distinguishes Atlantic from Indo-Pacific rookeries. Phylogeographic patterns in the sooty tern are compared to those in other colonially nesting seabirds, as well as in the green turtle (Chelonia mydas), an analogue of tropical seabirds in some salient aspects of natural history. Phylogeographic structure within an ocean is normally weak in seabirds, unlike the pronounced matrilineal structure in green turtles. However, the phylogeographic partition between Atlantic and Indo-Pacific rookeries in sooty terns mirrors, albeit in shallower evolutionary time, the major matrilineal subdivision in green turtles. Thus, global geology has apparently influenced historical gene movements in these two circumtropical species.

Beach erosion and nest site selection by the leatherback sea turtle Dermochelys coriacea (Testudines: Dermochelyidae) and implications for management practices at Playa Gandoca, Costa Rica.

PubMed

Spanier, Matthew J

2010-12-01

Leatherback sea turtles (Dermochelys coriacea) nest on dynamic, erosion-prone beaches. Erosive processes and resulting nest loss have long been presumed to be a hindrance to clutch survival. In order to better understand how leatherbacks cope with unstable nesting beaches, I investigated the role of beach erosion in leatherback nest site selection at Playa Gandoca, Costa Rica. I also examined the potential effect of nest relocation, a conservation strategy in place at Playa Gandoca to prevent nest loss to erosion, on the temperature of incubating clutches. I monitored changes in beach structure as a result of erosion at natural nest sites during the time the nest was laid, as well as in subsequent weeks. To investigate slope as a cue for nest site selection, I measured the slope of the beach where turtles ascended from the sea to nest, as well as the slopes at other random locations on the beach for comparison. I examined temperature differences between natural and relocated nest sites with thermocouples placed in the sand at depths typical of leatherback nests. Nests were distributed non-randomly in a clumped distribution along the length of the beach and laid at locations that were not undergoing erosion. The slope at nest sites was significantly different than at randomly chosen locations on the beach. The sand temperature at nest depths was significantly warmer at natural nest sites than at locations of relocated nests. The findings of this study suggest leatherbacks actively select nest sites that are not undergoing erosive processes, with slope potentially being used as a cue for site selection. The relocation of nests appears to be inadvertently cooling the nest environment. Due to the fact that leatherback clutches undergo temperature-dependent sex determination, the relocation of nests may be producing an unnatural male biasing of hatchlings. The results of this study suggest that the necessity of relocation practices, largely in place to protect nests from erosion, should be reevaluated to ensure the proper conservation of this critically endangered species.

Clam Shell Dredging in Lakes Pontchartrain and Maurepas, Louisiana. Volume 1. Final Environmental Impact Statement and Appendixes

DTIC Science & Technology

1987-11-01

favorable nesting habitats. Viosca (1961) felt ridleys preferred to nest in the loose sand of the Chandeleur Islands rather than the compacted...Ceorgia. Southeastern Wildlife Services, Inc. Athens, Ca. 24 p. In Rabalais and Rabalais 1980. Hughes, G.R. 1972. The olive ridley sea-turtle...that may be potentially impacted by the proposed activity are the Kemp’s (Atlantic) ridley sea turtle, Lepidochelys kempi, which is endangered, and

Multi-Modal Homing in Sea Turtles: Modeling Dual Use of Geomagnetic and Chemical Cues in Island-Finding.

PubMed

Endres, Courtney S; Putman, Nathan F; Ernst, David A; Kurth, Jessica A; Lohmann, Catherine M F; Lohmann, Kenneth J

2016-01-01

Sea turtles are capable of navigating across large expanses of ocean to arrive at remote islands for nesting, but how they do so has remained enigmatic. An interesting example involves green turtles (Chelonia mydas) that nest on Ascension Island, a tiny land mass located approximately 2000 km from the turtles' foraging grounds along the coast of Brazil. Sensory cues that turtles are known to detect, and which might hypothetically be used to help locate Ascension Island, include the geomagnetic field, airborne odorants, and waterborne odorants. One possibility is that turtles use magnetic cues to arrive in the vicinity of the island, then use chemical cues to pinpoint its location. As a first step toward investigating this hypothesis, we used oceanic, atmospheric, and geomagnetic models to assess whether magnetic and chemical cues might plausibly be used by turtles to locate Ascension Island. Results suggest that waterborne and airborne odorants alone are insufficient to guide turtles from Brazil to Ascension, but might permit localization of the island once turtles arrive in its vicinity. By contrast, magnetic cues might lead turtles into the vicinity of the island, but would not typically permit its localization because the field shifts gradually over time. Simulations reveal, however, that the sequential use of magnetic and chemical cues can potentially provide a robust navigational strategy for locating Ascension Island. Specifically, one strategy that appears viable is following a magnetic isoline into the vicinity of Ascension Island until an odor plume emanating from the island is encountered, after which turtles might either: (1) initiate a search strategy; or (2) follow the plume to its island source. These findings are consistent with the hypothesis that sea turtles, and perhaps other marine animals, use a multi-modal navigational strategy for locating remote islands.

Organochlorine pesticides, PCBs, trace elements and metals in western pond turtle eggs from Oregon

USGS Publications Warehouse

Henny, Charles J.; Beal, K.F.; Bury, R. Bruce; Goggans, R.

2003-01-01

With increased concern over the status of reptile populations globally, contaminant studies should be part of species evaluations. We analyzed eggs of western pond turtles from Fern Ridge Reservoir in western Oregon for 20 organochlorine (OC) pesticides or metabolites, 42 congener-specific polychlorinated biphenyls (PCBs), and 16 trace elements or metals. These eggs represent the first of this species analyzed. The OC pesticides and PCB residue concentrations in the western pond turtle eggs were generally low and similar to those found in eggs of snapping turtles from a remote site in Ontario, Canada. Western pond turtle eggs also contained mercury and chromium, which are metals of special concern. Although few reptilian eggs have been analyzed for metals, the 44.9 mug/g dry weight chromium in a western pond turtle egg in this study may be the highest reported in a reptilian egg. We found no significant difference in contaminant concentrations in eggs from nests in Oregon, where all turtle eggs failed to hatch compared to those where some eggs hatched. During this initial project, however, we were unable to assess fully the role of OCs, PCBs and other contaminants in the western pond turtle decline. Factors other than contaminants may be involved. In another study, snapping turtle eggs near the Great Lakes-St. Lawrence River basin were much more contaminated with evidence reported of effects on sex differentiation and reproductive endocrine function. Egg hatchability, the only reproductive parameter monitored, may not be the most sensitive endpoint. Other endpoints, including endocrine function, deformity rates, growth rates, and sex determination need study.

Sex ratio estimations of loggerhead sea turtle hatchlings by histological examination and nest temperatures at Fethiye beach, Turkey

NASA Astrophysics Data System (ADS)

Kaska, Yakup; Ilgaz, Çetin; Özdemir, Adem; Başkale, Eyüp; Türkozan, Oğuz; Baran, Ibrahim; Stachowitsch, Michael

2006-07-01

Hatchling sex ratios in the loggerhead turtle ( Caretta caretta) were estimated by placing electronic temperature recorders in 21 nests at Fethiye beach during 2000 2002. Over the seasons, the mean temperature in the middle third of the incubation period ranged from 26.7 to 32.1°C, and incubation periods ranged from 49 to 67 days. Based on the mean temperatures during the middle third of the incubation period, and on histologically sexed dead hatchlings, the sex ratios of hatchlings at Fethiye beach were roughly equal, i.e. 60 65% of the hatchlings were females. This contrasts with the highly female-skewed sex ratios in loggerhead turtles elsewhere; Fethiye has a relatively high proportion of male hatchlings. For endangered sea turtles, the knowledge of hatchling sex ratios at different beaches, coupled with appropriate conservation measures, can make an important contribution to their survival.

Seasonal variation in plasma catecholamines and adipose tissue lipolysis in adult female green sea turtles (Chelonia mydas).

PubMed

Hamann, Mark; Limpus, Colin J; Whittier, Joan M

2003-02-15

We investigated three aspects of potential interrenal regulation of reproduction in female green sea turtles, Chelonia mydas. First, seasonal trends in plasma catecholamines were examined from female C. mydas at different stages of their reproductive cycles. Second, variation in catecholamine levels during a nesting season were analysed in relation to restraint time, and ecological variables such as nesting habitat, body size, and reproductive investment. Third, catecholamine and corticosterone (CORT) induced lipolysis was investigated with adipose tissue collected from gravid green turtles, using in vitro incubations. Plasma epinephrine (EPI) was lowest in non-vitellogenic (1.55 +/- 0.26 ng/ml) and post-breeding (1.57 +/- 0.22 ng/ml) females, and highest in courting females (2.87 +/- 0.28). Concentrations of norepinephrine (NE) and EPI were relatively constant throughout a nesting season, and not significantly related to restraint time, reproductive investment or nesting habitat. In vitro concentrations of CORT (>3 ng/ml) and NE (2 ng/ml) induced significant release of glycerol after 6h of incubation. Epinephrine tended to induce an antilipolytic affect at low concentrations (0.25 ng/ml) and a net lipolytic response at higher concentrations (>1 ng/ml). Our data suggest that EPI may play a role in regulating body condition during vitellogenesis, and maintaining energy stores during prolonged aphagia during courtship and nesting in female green sea turtles. Furthermore, we provide preliminary evidence that suggests that catecholamine production may be either down regulated or de-sensitised in gravid female C. mydas. Copyright 2003 Elsevier Science (USA)

Sand and nest temperatures and an estimate of hatchling sex ratio from the Heron Island green turtle ( Chelonia mydas) rookery, Southern Great Barrier Reef

NASA Astrophysics Data System (ADS)

Booth, David T.; Freeman, Candida

2006-11-01

Sand and nest temperatures were monitored during the 2002-2003 nesting season of the green turtle, Chelonia mydas, at Heron Island, Great Barrier Reef, Australia. Sand temperatures increased from ˜ 24°C early in the season to 27-29°C in the middle, before decreasing again. Beach orientation affected sand temperature at nest depth throughout the season; the north facing beach remained 0.7°C warmer than the east, which was 0.9°C warmer than the south, but monitored nest temperatures were similar across all beaches. Sand temperature at 100 cm depth was cooler than at 40 cm early in the season, but this reversed at the end. Nest temperatures increased 2-4°C above sand temperatures during the later half of incubation due to metabolic heating. Hatchling sex ratio inferred from nest temperature profiles indicated a strong female bias.

Genetic variation, multiple paternity, and measures of reproductive success in the critically endangered hawksbill turtle (Eretmochelys imbricata).

PubMed

González-Garza, Blanca Idalia; Stow, Adam; Sánchez-Teyer, Lorenzo Felipe; Zapata-Pérez, Omar

2015-12-01

The Yucatán Peninsula in Mexico contains some of the largest breeding groups of the globally distributed and critically endangered hawksbill turtle (Eretmochelys imbricata). An improved understanding of the breeding system of this species and how its genetic variation is structured among nesting areas is required before the threats to its survival can be properly evaluated. Here, we genotype 1195 hatchlings and 41 nesting females at 12 microsatellite loci to assess levels of multiple paternity, genetic variation and whether individual levels of homozygosity are associated with reproductive success. Of the 50 clutches analyzed, only 6% have multiple paternity. The distribution of pairwise relatedness among nesting localities (rookeries) was not random with elevated within-rookery relatedness, and declining relatedness with geographic distance indicating some natal philopatry. Although there was no strong evidence that particular rookeries had lost allelic variation via drift, younger turtles had significantly lower levels of genetic variation than older turtles, suggesting some loss of genetic variation. At present there is no indication that levels of genetic variation are associated with measures of reproductive success such as clutch size, hatching success, and frequency of infertile eggs.

A model for simulating the active dispersal of juvenile sea turtles with a case study on western Pacific leatherback turtles.

PubMed

Gaspar, Philippe; Lalire, Maxime

2017-01-01

Oceanic currents are known to broadly shape the dispersal of juvenile sea turtles during their pelagic stage. Accordingly, simple passive drift models are widely used to investigate the distribution at sea of various juvenile sea turtle populations. However, evidence is growing that juveniles do not drift purely passively but also display some swimming activity likely directed towards favorable habitats. We therefore present here a novel Sea Turtle Active Movement Model (STAMM) in which juvenile sea turtles actively disperse under the combined effects of oceanic currents and habitat-driven movements. This model applies to all sea turtle species but is calibrated here for leatherback turtles (Dermochelys coriacea). It is first tested in a simulation of the active dispersal of juveniles originating from Jamursba-Medi, a main nesting beach of the western Pacific leatherback population. Dispersal into the North Pacific Ocean is specifically investigated. Simulation results demonstrate that, while oceanic currents broadly shape the dispersal area, modeled habitat-driven movements strongly structure the spatial and temporal distribution of juveniles within this area. In particular, these movements lead juveniles to gather in the North Pacific Transition Zone (NPTZ) and to undertake seasonal north-south migrations. More surprisingly, juveniles in the NPTZ are simulated to swim mostly towards west which considerably slows down their progression towards the American west coast. This increases their residence time, and hence the risk of interactions with fisheries, in the central and eastern part of the North Pacific basin. Simulated habitat-driven movements also strongly reduce the risk of cold-induced mortality. This risk appears to be larger among the juveniles that rapidly circulate into the Kuroshio than among those that first drift into the North Equatorial Counter Current (NECC). This mechanism might induce marked interannual variability in juvenile survival as the strength and position of the NECC are directly linked to El Niño activity.

A model for simulating the active dispersal of juvenile sea turtles with a case study on western Pacific leatherback turtles

PubMed Central

Lalire, Maxime

2017-01-01

Oceanic currents are known to broadly shape the dispersal of juvenile sea turtles during their pelagic stage. Accordingly, simple passive drift models are widely used to investigate the distribution at sea of various juvenile sea turtle populations. However, evidence is growing that juveniles do not drift purely passively but also display some swimming activity likely directed towards favorable habitats. We therefore present here a novel Sea Turtle Active Movement Model (STAMM) in which juvenile sea turtles actively disperse under the combined effects of oceanic currents and habitat-driven movements. This model applies to all sea turtle species but is calibrated here for leatherback turtles (Dermochelys coriacea). It is first tested in a simulation of the active dispersal of juveniles originating from Jamursba-Medi, a main nesting beach of the western Pacific leatherback population. Dispersal into the North Pacific Ocean is specifically investigated. Simulation results demonstrate that, while oceanic currents broadly shape the dispersal area, modeled habitat-driven movements strongly structure the spatial and temporal distribution of juveniles within this area. In particular, these movements lead juveniles to gather in the North Pacific Transition Zone (NPTZ) and to undertake seasonal north-south migrations. More surprisingly, juveniles in the NPTZ are simulated to swim mostly towards west which considerably slows down their progression towards the American west coast. This increases their residence time, and hence the risk of interactions with fisheries, in the central and eastern part of the North Pacific basin. Simulated habitat-driven movements also strongly reduce the risk of cold-induced mortality. This risk appears to be larger among the juveniles that rapidly circulate into the Kuroshio than among those that first drift into the North Equatorial Counter Current (NECC). This mechanism might induce marked interannual variability in juvenile survival as the strength and position of the NECC are directly linked to El Niño activity. PMID:28746389

Artisanal Green Turtle, Chelonia mydas, fishery of Caribbean Nicaragua: I. Catch rates and trends, 1991-2011.

PubMed

Lagueux, Cynthia J; Campbell, Cathi L; Strindberg, Samantha

2014-01-01

This is the first assessment of catch rates for the legal, artisanal green turtle, Chelonia mydas, fishery in Caribbean Nicaragua. Data were collected by community members, monitoring up to 14 landing sites from 1991 to 2011. We examined take levels, and temporal and spatial variability in catch rates for the overall fishery, by region, and community using General Additive Mixed Models (GAMMs). More than 171,556 green turtles were killed during the period, with a mean estimated minimum 8,169±2,182 annually. There was a statistically significant decline in catch rates overall. Catch rates peaked in 1997 and 2002, followed by a downward trend, particularly from mid-2008 to the end of the study period. Similar downward trends were evident in both study regions. Community specific catch rate trends also indicated declines with decreases ranging from 21% to 90%. Decrease in catch rates in Nicaragua is cause for concern even though the principal source rookery at Tortuguero, Costa Rica, shows an increase in nesting activity. Explanations for the apparent discrepancy between the increasing trend at Tortuguero and decreasing catch rate trends in Nicaragua include: i) an increase in reproductive output, ii) insufficient time has passed to observe the impact of the fishery on the rookery due to a time lag, iii) changes in other segments of the population have not been detected since only nesting activity is monitored, iv) the expansive northern Nicaragua foraging ground may provide a refuge for a sufficient portion of the Tortuguero rookery, and/or v) a larger than expected contribution of non-Tortuguero rookeries occurring in Nicaragua turtle fishing areas. Our results highlight the need for close monitoring of rookeries and in-water aggregations in the Caribbean. Where consumptive use still occurs, nations sharing this resource should implement scientifically based limits on exploitation to ensure sustainability and mitigate impacts to regional population diversity.

Artisanal Green Turtle, Chelonia mydas, Fishery of Caribbean Nicaragua: I. Catch Rates and Trends, 1991–2011

PubMed Central

Lagueux, Cynthia J.; Campbell, Cathi L.; Strindberg, Samantha

2014-01-01

This is the first assessment of catch rates for the legal, artisanal green turtle, Chelonia mydas, fishery in Caribbean Nicaragua. Data were collected by community members, monitoring up to 14 landing sites from 1991 to 2011. We examined take levels, and temporal and spatial variability in catch rates for the overall fishery, by region, and community using General Additive Mixed Models (GAMMs). More than 171,556 green turtles were killed during the period, with a mean estimated minimum 8,169±2,182 annually. There was a statistically significant decline in catch rates overall. Catch rates peaked in 1997 and 2002, followed by a downward trend, particularly from mid-2008 to the end of the study period. Similar downward trends were evident in both study regions. Community specific catch rate trends also indicated declines with decreases ranging from 21% to 90%. Decrease in catch rates in Nicaragua is cause for concern even though the principal source rookery at Tortuguero, Costa Rica, shows an increase in nesting activity. Explanations for the apparent discrepancy between the increasing trend at Tortuguero and decreasing catch rate trends in Nicaragua include: i) an increase in reproductive output, ii) insufficient time has passed to observe the impact of the fishery on the rookery due to a time lag, iii) changes in other segments of the population have not been detected since only nesting activity is monitored, iv) the expansive northern Nicaragua foraging ground may provide a refuge for a sufficient portion of the Tortuguero rookery, and/or v) a larger than expected contribution of non-Tortuguero rookeries occurring in Nicaragua turtle fishing areas. Our results highlight the need for close monitoring of rookeries and in-water aggregations in the Caribbean. Where consumptive use still occurs, nations sharing this resource should implement scientifically based limits on exploitation to ensure sustainability and mitigate impacts to regional population diversity. PMID:24740258

Reproductive Disorders and Perinatology of Sea Turtles.

PubMed

Spadola, Filippo; Morici, Manuel; Santoro, Mario; Oliveri, Matteo; Insacco, Gianni

2017-05-01

Sea turtles' reproductive disorders are underdiagnosed, but potentially, there are several diseases that may affect gonads, genitalia, and annexes. Viruses, bacteria, and parasites may cause countless disorders, but more frequently the cause is traumatic or linked to human activities. Furthermore, veterinary management of the nest is of paramount importance as well as the care of newborns (also in captivity). This article gives an overview on the methods used to manage nests and reproductive activities of these endangered chelonians species. Copyright © 2016 Elsevier Inc. All rights reserved.

Multi-Modal Homing in Sea Turtles: Modeling Dual Use of Geomagnetic and Chemical Cues in Island-Finding

PubMed Central

Endres, Courtney S.; Putman, Nathan F.; Ernst, David A.; Kurth, Jessica A.; Lohmann, Catherine M. F.; Lohmann, Kenneth J.

2016-01-01

Sea turtles are capable of navigating across large expanses of ocean to arrive at remote islands for nesting, but how they do so has remained enigmatic. An interesting example involves green turtles (Chelonia mydas) that nest on Ascension Island, a tiny land mass located approximately 2000 km from the turtles’ foraging grounds along the coast of Brazil. Sensory cues that turtles are known to detect, and which might hypothetically be used to help locate Ascension Island, include the geomagnetic field, airborne odorants, and waterborne odorants. One possibility is that turtles use magnetic cues to arrive in the vicinity of the island, then use chemical cues to pinpoint its location. As a first step toward investigating this hypothesis, we used oceanic, atmospheric, and geomagnetic models to assess whether magnetic and chemical cues might plausibly be used by turtles to locate Ascension Island. Results suggest that waterborne and airborne odorants alone are insufficient to guide turtles from Brazil to Ascension, but might permit localization of the island once turtles arrive in its vicinity. By contrast, magnetic cues might lead turtles into the vicinity of the island, but would not typically permit its localization because the field shifts gradually over time. Simulations reveal, however, that the sequential use of magnetic and chemical cues can potentially provide a robust navigational strategy for locating Ascension Island. Specifically, one strategy that appears viable is following a magnetic isoline into the vicinity of Ascension Island until an odor plume emanating from the island is encountered, after which turtles might either: (1) initiate a search strategy; or (2) follow the plume to its island source. These findings are consistent with the hypothesis that sea turtles, and perhaps other marine animals, use a multi-modal navigational strategy for locating remote islands. PMID:26941625

The anti-predator role of within-nest emergence synchrony in sea turtle hatchlings.

PubMed

Santos, Robson G; Pinheiro, Hudson Tercio; Martins, Agnaldo Silva; Riul, Pablo; Bruno, Soraya Christina; Janzen, Fredric J; Ioannou, Christos C

2016-07-13

Group formation is a common behaviour among prey species. In egg-laying animals, despite the various factors that promote intra-clutch variation leading to asynchronous hatching and emergence from nests, synchronous hatching and emergence occurs in many taxa. This synchrony may be adaptive by reducing predation risk, but few data are available in any natural system, even for iconic examples of the anti-predator function of group formation. Here, we show for the first time that increased group size (number of hatchlings emerging together from a nest) reduces green turtle (Chelonia mydas) hatchling predation. This effect was only observed earlier in the night when predation pressure was greatest, indicated by the greatest predator abundance and a small proportion of predators preoccupied with consuming captured prey. Further analysis revealed that the effect of time of day was due to the number of hatchlings already killed in an evening; this, along with the apparent lack of other anti-predatory mechanisms for grouping, suggests that synchronous emergence from a nest appears to swamp predators, resulting in an attack abatement effect. Using a system with relatively pristine conditions for turtle hatchlings and their predators provides a more realistic environmental context within which intra-nest synchronous emergence has evolved. © 2016 The Author(s).

NASA Kennedy Space Center: Contributions to Sea Turtle Science and Conservation

NASA Technical Reports Server (NTRS)

Provancha, Jane A.; Phillips, Lynne V.; Mako, Cheryle L.

2018-01-01

The National Aeronautics and Space Administration (NASA) is a United States (US) federal agency that oversees US space exploration and aeronautical research. NASA's primary launch site, Kennedy Space Center (KSC) is located along the east coast of Florida, on Cape Canaveral and the western Atlantic Ocean. The natural environment within KSC's large land boundaries, not only functions as an extensive safety buffer-area, it performs simultaneously as a wildlife refuge and a national seashore. In the early 1960s, NASA was developing KSC for rocket launches and the US was establishing an awareness of, and commitment to protecting the environment. The US began creating regulations that required the consideration of the environment when taking action on federal land or with federal funds. The timing of the US Endangered Species Act (1973), the US National Environmental Policy Act (1972), coincided with the planning and implementation of the US Space Shuttle Program. This resulted in the first efforts to evaluate the impacts of space launch operation operations on waterways, air quality, habitats, and wildlife. The first KSC fauna and flora baseline studies were predominantly performed by University of Central Florida (then Florida Technological University). Numerous species of relative importance were observed and sea turtles were receiving regulatory review and protection as surveys by Dr. L Ehrhart (UCF) from 1973-1978 described turtles nesting along the KSC beaches and foraging in the KSC lagoon systems. These data were used in the first NASA Environmental Impact Statement for the Space Transportation System (shuttle program) in 1980. In 1982, NASA began a long term ecological monitoring program with contracted scientists on site. This included efforts to track sea turtle status and trends at KSC and maintain protective measures for these species. Many studies and collaborations have occurred on KSC over these last 45 years with agencies (USFWS, NOAA, NAVY), students, and universities (UCF, University of Toronto, Texas A&M, UF). This presentation will review the various studies and collaborations on sea turtles at KSC that include: nest distributions and success, stranding network development, aerial survey testing for nest counts, predator control assessments, the earliest baseline blood chemistry health determinations on nesting females, stress hormones in nesting females, multi-year study of hatchling sex ratios, genetics, species composition, abundance and distribution of in-water juveniles, turtle cold stun response, exterior lighting impacts and control, and satellite tag tracking of post-nesting turtles in the vicinity of near shore shoals and sand mining sites. Through these studies, monitoring, and recommendations, KSC has provided excellent stewardship and protection of the local environment. While conducting its space program mission, KSC has also made significant contributions of information for agencies charged with the conservation and management of these species

Seasonal trends in nesting leatherback turtle (Dermochelys coriacea) serum proteins further verify capital breeding hypothesis

PubMed Central

Perrault, Justin R.; Wyneken, Jeanette; Page-Karjian, Annie; Merrill, Anita; Miller, Debra L.

2014-01-01

Serum protein concentrations provide insight into the nutritional and immune status of organisms. It has been suggested that some marine turtles are capital breeders that fast during the nesting season. In this study, we documented serum proteins in neophyte and remigrant nesting leatherback sea turtles (Dermochelys coriacea). This allowed us to establish trends across the nesting season to determine whether these physiological parameters indicate if leatherbacks forage or fast while on nesting grounds. Using the biuret method and agarose gel electrophoresis, total serum protein (median = 5.0 g/dl) and protein fractions were quantified and include pre-albumin (median = 0.0 g/dl), albumin (median = 1.81 g/dl), α1-globulin (median = 0.90 g/dl), α2-globulin (median = 0.74 g/dl), total α-globulin (median = 1.64 g/dl), β-globulin (median = 0.56 g/dl), γ-globulin (median = 0.81 g/dl) and total globulin (median = 3.12 g/dl). The albumin:globulin ratio (median = 0.59) was also calculated. Confidence intervals (90%) were used to establish reference intervals. Total protein, albumin and total globulin concentrations declined in successive nesting events. Protein fractions declined at less significant rates or remained relatively constant during the nesting season. Here, we show that leatherbacks are most likely fasting during the nesting season. A minimal threshold of total serum protein concentrations of around 3.5–4.5 g/dl may physiologically signal the end of the season's nesting for individual leatherbacks. The results presented here lend further insight into the interaction between reproduction, fasting and energy reserves and will potentially improve the conservation and management of this imperiled species. PMID:27293623

Molecular identification and first report of mitochondrial COI gene haplotypes in the hawksbill turtle Eretmochelys imbricata (Testudines: Cheloniidae) in the Colombian Caribbean nesting colonies.

PubMed

Daza-Criado, L; Hernández-Fernández, J

2014-02-21

Hawksbill sea turtles Eretmochelys imbricata are found extensively around the world, including the Atlantic, Pacific, and Indian Oceans; the Persian Gulf, and the Red and Mediterranean Seas. Populations of this species are affected by international trafficking of their shields, meat, and eggs, making it a critically endangered animal. We determined the haplotypes of 17 hawksbill foraging turtles of Islas del Rosario (Bolivar) and of the nesting beach Don Diego (Magdalena) in the Colombian Caribbean based on amplification and sequencing of the mitochondrial gene cytochrome oxidase c subunit I (COI). We identified 5 haplotypes, including EI-A1 previously reported in Puerto Rico, which was similar to 10 of the study samples. To our knowledge, the remaining 4 haplotypes have not been described. Samples EICOI11 and EICOI3 showed 0.2% divergence from EI-A1, by a single nucleotide change, and were classified as the EI-A2 haplotype. EICOI6, EICOI14, and EICOI12 samples showed 0.2% divergence from EI-A1 and 0.3% divergence from EI-A2 and were classified as EI-A3 haplotype. Samples EICOI16 and EICOI15 presented 5 nucleotide changes each and were classified as 2 different haplotypes, EI-A4 and EI-A5, respectively. The last 2 haplotypes had higher nucleotide diversity (K2P=1.7%) than that by the first 3 haplotypes. EI-A1 and EI-A2 occurred in nesting individuals, and EI-A2, EI-A3, EI-A4, and EI-A5 occurred in foraging individuals. The description of the haplotypes may be associated with reproductive migrations or foraging and could support the hypothesis of natal homing. Furthermore, they can be used in phylogeographic studies.

Demographics, diet, movements, and survival of an isolated, unmanaged raccoon Procyon lotor (Procyonidae, Carnivora) population on the Outer Banks of North Carolina

USGS Publications Warehouse

Parsons, Arielle Waldstein; Simons, Theodore R.; O'Connell, Allan F.; Stoskopf, Michael K.

2012-01-01

Raccoons (Procyon lotor) are highly adaptable meso-carnivores that inhabit many environments, including the Atlantic barrier islands, where their role as predators of declining, beach-nesting bird and turtle species is of particular interest. Population models that improve our understanding of predator-prey dynamics are receiving increasing attention in the literature; however, their effective application requires site-specific information on population parameters. We studied an unharvested raccoon population on the Outer Banks of North Carolina and evaluated spatial and seasonal differences in a number of population/demographic factors of raccoons inhabiting areas of high and low human activity. Raccoons denned and foraged primarily in salt marsh habitats but shifted their movements in response to changes in seasonal resource conditions. The population was skewed toward older animals and exhibited delayed breeding, typical of populations at high density with few sources of mortality. Diet and movement analysis indicated shorebird and turtle predation was attributed to a small number of individual raccoons. Although seasonal resources appeared adequate to sustain a high population density of raccoons, poor body condition and low recruitment suggested a population near carrying capacity.

Migration, foraging, and residency patterns for Northern Gulf loggerheads: implications of local threats and international movements

USGS Publications Warehouse

Hart, Kristen M.; Lamont, Margaret M.; Sartain-Iverson, Autumn R.; Fujisaki, Ikuko

2014-01-01

Northern Gulf of Mexico (NGoM) loggerheads (Caretta caretta) make up one of the smallest subpopulations of this threatened species and have declining nest numbers. We used satellite telemetry and a switching state-space model to identify distinct foraging areas used by 59 NGoM loggerheads tagged during 2010–2013. We tagged turtles after nesting at three sites, 1 in Alabama (Gulf Shores; n = 37) and 2 in Florida (St. Joseph Peninsula; n = 20 and Eglin Air Force Base; n = 2). Peak migration time was 22 July to 9 August during which >40% of turtles were in migration mode; the mean post-nesting migration period was 23.0 d (±13.8 d SD). After displacement from nesting beaches, 44 turtles traveled to foraging sites where they remained resident throughout tracking durations. Selected foraging locations were variable distances from tagging sites, and in 5 geographic regions; no turtles selected foraging sites outside the Gulf of Mexico (GoM). Foraging sites delineated using 50% kernel density estimation were located a mean distance of 47.6 km from land and in water with mean depth of −32.5 m; other foraging sites, delineated using minimum convex polygons, were located a mean distance of 43.0 km from land and in water with a mean depth of −24.9 m. Foraging sites overlapped with known trawling activities, oil and gas extraction activities, and the footprint of surface oiling during the 2010 Deepwater Horizon oil spill (n = 10). Our results highlight the year-round use of habitats in the GoM by loggerheads that nest in the NGoM. Our findings indicate that protection of females in this subpopulation requires both international collaborations and management of threats that spatially overlap with distinct foraging habitats.

Migration, foraging, and residency patterns for Northern Gulf loggerheads: implications of local threats and international movements.

PubMed

Hart, Kristen M; Lamont, Margaret M; Sartain, Autumn R; Fujisaki, Ikuko

2014-01-01

Northern Gulf of Mexico (NGoM) loggerheads (Caretta caretta) make up one of the smallest subpopulations of this threatened species and have declining nest numbers. We used satellite telemetry and a switching state-space model to identify distinct foraging areas used by 59 NGoM loggerheads tagged during 2010-2013. We tagged turtles after nesting at three sites, 1 in Alabama (Gulf Shores; n = 37) and 2 in Florida (St. Joseph Peninsula; n = 20 and Eglin Air Force Base; n = 2). Peak migration time was 22 July to 9 August during which >40% of turtles were in migration mode; the mean post-nesting migration period was 23.0 d (±13.8 d SD). After displacement from nesting beaches, 44 turtles traveled to foraging sites where they remained resident throughout tracking durations. Selected foraging locations were variable distances from tagging sites, and in 5 geographic regions; no turtles selected foraging sites outside the Gulf of Mexico (GoM). Foraging sites delineated using 50% kernel density estimation were located a mean distance of 47.6 km from land and in water with mean depth of -32.5 m; other foraging sites, delineated using minimum convex polygons, were located a mean distance of 43.0 km from land and in water with a mean depth of -24.9 m. Foraging sites overlapped with known trawling activities, oil and gas extraction activities, and the footprint of surface oiling during the 2010 Deepwater Horizon oil spill (n = 10). Our results highlight the year-round use of habitats in the GoM by loggerheads that nest in the NGoM. Our findings indicate that protection of females in this subpopulation requires both international collaborations and management of threats that spatially overlap with distinct foraging habitats.

Tracking leatherback turtles from the world's largest rookery: assessing threats across the South Atlantic

PubMed Central

Witt, Matthew J.; Augowet Bonguno, Eric; Broderick, Annette C.; Coyne, Michael S.; Formia, Angela; Gibudi, Alain; Mounguengui Mounguengui, Gil Avery; Moussounda, Carine; NSafou, Monique; Nougessono, Solange; Parnell, Richard J.; Sounguet, Guy-Philippe; Verhage, Sebastian; Godley, Brendan J.

2011-01-01

Despite extensive work carried out on leatherback turtles (Dermochelys coriacea) in the North Atlantic and Indo-Pacific, very little is known of the at-sea distribution of this species in the South Atlantic, where the world's largest population nests in Gabon (central Africa). This paucity of data is of marked concern given the pace of industrialization in fisheries with demonstrable marine turtle bycatch in African/Latin American waters. We tracked the movements of 25 adult female leatherback turtles obtaining a range of fundamental and applied insights, including indications for methodological advancement. Individuals could be assigned to one of three dispersal strategies, moving to (i) habitats of the equatorial Atlantic, (ii) temperate habitats off South America or (iii) temperate habitats off southern Africa. While occupying regions with high surface chlorophyll concentrations, these strategies exposed turtles to some of the world's highest levels of longline fishing effort, in addition to areas with coastal gillnet fisheries. Satellite tracking highlighted that at least 11 nations should be involved in the conservation of this species in addition to those with distant fishing fleets. The majority of tracking days were, however, spent in the high seas, where effective implementation of conservation efforts is complex to achieve. PMID:21208949

Heritable variation in heat shock gene expression: a potential mechanism for adaptation to thermal stress in embryos of sea turtles.

PubMed

Tedeschi, J N; Kennington, W J; Tomkins, J L; Berry, O; Whiting, S; Meekan, M G; Mitchell, N J

2016-01-13

The capacity of species to respond adaptively to warming temperatures will be key to their survival in the Anthropocene. The embryos of egg-laying species such as sea turtles have limited behavioural means for avoiding high nest temperatures, and responses at the physiological level may be critical to coping with predicted global temperature increases. Using the loggerhead sea turtle (Caretta caretta) as a model, we used quantitative PCR to characterise variation in the expression response of heat-shock genes (hsp60, hsp70 and hsp90; molecular chaperones involved in cellular stress response) to an acute non-lethal heat shock. We show significant variation in gene expression at the clutch and population levels for some, but not all hsp genes. Using pedigree information, we estimated heritabilities of the expression response of hsp genes to heat shock and demonstrated both maternal and additive genetic effects. This is the first evidence that the heat-shock response is heritable in sea turtles and operates at the embryonic stage in any reptile. The presence of heritable variation in the expression of key thermotolerance genes is necessary for sea turtles to adapt at a molecular level to warming incubation environments. © 2016 The Author(s).

Heritable variation in heat shock gene expression: a potential mechanism for adaptation to thermal stress in embryos of sea turtles

PubMed Central

Kennington, W. J.; Tomkins, J. L.; Berry, O.; Whiting, S.; Meekan, M. G.; Mitchell, N. J.

2016-01-01

The capacity of species to respond adaptively to warming temperatures will be key to their survival in the Anthropocene. The embryos of egg-laying species such as sea turtles have limited behavioural means for avoiding high nest temperatures, and responses at the physiological level may be critical to coping with predicted global temperature increases. Using the loggerhead sea turtle (Caretta caretta) as a model, we used quantitative PCR to characterise variation in the expression response of heat-shock genes (hsp60, hsp70 and hsp90; molecular chaperones involved in cellular stress response) to an acute non-lethal heat shock. We show significant variation in gene expression at the clutch and population levels for some, but not all hsp genes. Using pedigree information, we estimated heritabilities of the expression response of hsp genes to heat shock and demonstrated both maternal and additive genetic effects. This is the first evidence that the heat-shock response is heritable in sea turtles and operates at the embryonic stage in any reptile. The presence of heritable variation in the expression of key thermotolerance genes is necessary for sea turtles to adapt at a molecular level to warming incubation environments. PMID:26763709

An Immunohistochemical Approach to Identify the Sex of Young Marine Turtles.

PubMed

Tezak, Boris M; Guthrie, Kathleen; Wyneken, Jeanette

2017-08-01

Marine turtles exhibit temperature-dependent sex determination (TSD). During critical periods of embryonic development, the nest's thermal environment directs whether an embryo will develop as a male or female. At warmer sand temperatures, nests tend to produce female-biased sex ratios. The rapid increase of global temperature highlights the need for a clear assessment of its effects on sea turtle sex ratios. However, estimating hatchling sex ratios at rookeries remains imprecise due to the lack of sexual dimorphism in young marine turtles. We rely mainly upon laparoscopic procedures to verify hatchling sex; however, in some species, morphological sex can be ambiguous even at the histological level. Recent studies using immunohistochemical (IHC) techniques identified that embryonic snapping turtle (Chelydra serpentina) ovaries overexpressed a particular cold-induced RNA-binding protein in comparison to testes. This feature allows the identification of females vs. males. We modified this technique to successfully identify the sexes of loggerhead sea turtle (Caretta caretta) hatchlings, and independently confirmed the results by standard histological and laparoscopic methods that reliably identify sex in this species. We next tested the CIRBP IHC method on gonad samples from leatherback turtles (Dermochelys coriacea). Leatherbacks display delayed gonad differentiation, when compared to other sea turtles, making hatchling gonads difficult to sex using standard H&E stain histology. The IHC approach was successful in both C. caretta and D. coriacea samples, offering a much-needed tool to establish baseline hatchling sex ratios, particularly for assessing impacts of climate change effects on leatherback turtle hatchlings and sea turtle demographics. Anat Rec, 300:1512-1518, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Hatching behavior of eastern long-necked turtles (Chelodina longicollis): The influence of asynchronous environments on embryonic heart rate and phenotype.

PubMed

McGlashan, Jessica K; Loudon, Fiona K; Thompson, Michael B; Spencer, Ricky-John

2015-10-01

Variable temperatures within a nest cause asynchronous development within clutches of freshwater turtle embryos, yet synchronous hatching occurs and is thought to be an important survival strategy for hatchlings. Metabolic compensation and circadian rhythms in heart rates of embryonic turtles indicate the potential of communication between embryos in a nest. Heart rates were used to identify metabolic circadian rhythms in clutches of an Australian freshwater turtle (Chelodina longicollis) and determine whether embryos metabolically compensate and hatch synchronously when incubated in asynchronous environments. The effects of a group environment during incubation on egg development and incubation period were also investigated during the final 3 weeks of development. Chelodina longicollis hatch synchronously and metabolically compensate so that less advanced embryos catch up to more advanced clutch-mates. Heart rates of embryos remained stable from week 4-7 in asynchronous (M=89 bpm) and synchronous (M=92 bpm) groups and declined in the final 2 weeks of incubation (M=72 and 77 bpm). Circadian rhythms were present throughout development and diel heart rates of embryos in asynchronous groups showed less deviation from the mean (M=-0.5 bpm) than synchronous groups (M=-4 bpm). Eggs incubated in groups had a significantly shorter incubation period than eggs incubated individually. Phenotypic traits including size, performance, and growth of all hatchlings were not affected. Egg position within a turtle nest is important for coordinating development throughout incubation and facilitating synchronous hatching. Copyright © 2015 Elsevier Inc. All rights reserved.

Sedimentology, geochemistry and rock magnetic properties of beach sands in Galapagos Islands - implications for nesting marine turtles

NASA Astrophysics Data System (ADS)

Perez-Cruz, L.; Urrutia-Fucugauchi, J.; Vazquez-Gutierrez, F.; Carranza-Edwards, A.

2007-12-01

Marine turtles are well known for their navigation ability in the open ocean and fidelity to nesting beaches. Green turtle adult females migrate from foraging areas to island nesting beaches, traveling hundreds or thousands of kilometers each way. The marine turtle breeding in the Galapagos Islands is the Green Sea Turtle (Chelonia mydas agassisi); fairly common throughout the islands but with nesting sites located at Las Bachas (Santa Cruz), Barahona and Quinta Playa (Isabela), Salinas (Baltra), Gardner Bay (Española) and Bartolomé Islet. In order to characterize and to identify the geochemical signature of nesting marine turtle beaches in Galapagos Islands, sedimentological, geochemical and rock magnetic parameters are used. A total of one hundred and twenty sand samples were collected in four beaches to relate compositional characteristics between equivalent areas, these are: Las Bachas, Salinas, Barahona and Quinta Playa. Grain size is evaluated using laser particle analysis (Model Coulter LS 230). Bulk ICP-MS geochemical analysis is performed, following trace elements are analyzed: Al, V, Cr, Co, Ni, Cu, Zn, Cd, Ba, Pb, Fe, Mn, K, Na, Mg, Sr, Ca and Hg; and low-field magnetic susceptibility is measured in all samples at low and high frequencies. Granulometric analysis showed that Barahona and Quinta Playa are characterized for fine grained sands. In contrast, Salinas and Las Bachas exhibit medium to coarse sands. Trace metals concentrations and magnetic susceptibility show different distribution patterns in the beach sands. Calcium is the most abundant element in the samples. In particular, Co, K, and Na show similar concentrations in the four beaches. Las Bachas beach shows highest concentrations of Pb and Hg (maximum values 101.1 and 118.5 mg/kg, respectively), we suggest that the enrichment corresponds to an anthropogenic signal. Salinas beach samples show high concentrations of Fe, V, Cr, Zn, Mn and the highest values of magnetic susceptibility (maximum 932 10-6 SI), we propose, a human activity influence less evident than in Bachas beach that could overlap the contribution of continent source. Quinta Playa sands show the maximum concentration of calcium and also high concentration of Fe and Mg, and relatively high values of magnetic susceptibility. Ca results from marine biogenic carbonates (mainly coral reefs). Barahona also show high concentrations in calcium that could be correlated with the presence of biogenous source around the beach.

Relationship between organochlorine pesticides and stress indicators in hawksbill sea turtle (Eretmochelys imbricata) nesting at Punta Xen (Campeche), Southern Gulf of Mexico.

PubMed

Tremblay, Nelly; Ortíz Arana, Alejandro; González Jáuregui, Mauricio; Rendón-von Osten, Jaime

2017-03-01

Data on the impact of environmental pollution on the homeostasis of sea turtles remains scarce, particularly in the Southern Gulf of Mexico. As many municipalities along the coastline of the Yucatan Peninsula do not rely on a waste treatment plant, these organisms could be particularly vulnerable. We searched for relationships between the presence of organochlorine pesticides (OCP) and the level of several oxidative and pollutant stress indicators of the hawksbill sea turtle (Eretmochelys imbricata) during the 2010 nesting season at Punta Xen (Campeche, Mexico). Of the 30 sampled sea turtles, endosulfans, aldrin related (aldrin, endrin, dieldrin, endrin ketone, endrin aldehyde) and dichlorodiphenyldichloroethylene (DDT) families were detected in 17, 21 and 26, respectively. Significant correlation existed between the size of sea turtles with the concentration of methoxychlor, cholinesterase activity in plasma and heptachlors family, and catalase activity and hexachlorohexane family. Cholinesterase activity in washed erythrocytes and lipid peroxidation were positively correlated with glutathione reductase activity. Antioxidant enzyme actions seem adequate as no lipids damages were correlated with any OCPs. Future studies are necessary to evaluate the effect of OCPs on males of the area due to the significant detection of methoxychlor, which target endocrine functioning and increases its concentration with sea turtles size.

Synchronous activity lowers the energetic cost of nest escape for sea turtle hatchlings.

PubMed

Rusli, Mohd Uzair; Booth, David T; Joseph, Juanita

2016-05-15

A potential advantage of group movement in animals is increased locomotion efficiency. This implies a reduced energetic cost for individuals that occur in larger groups such as herds, flocks and schools. When chelonian hatchlings hatch in the underground nest with finite energy for their post-hatching dispersal phase, they face the challenge of minimizing energetic expenditure while escaping the nest. The term 'social facilitation' has been used to describe the combined digging effort of sea turtle hatchlings during nest escape. Given that in a normal clutch, a substantial part of the energy reserve within the residual yolk is used by hatchlings in the digging out process, a decreased cohort size may reduce the energy reserve available to cross the beach and sustain the initial swimming frenzy. This hypothesis was experimentally tested by varying cohort size in hatchling green turtles (Chelonia mydas) and measuring energy expenditure during the nest escape process using open-flow respirometry. The energetic cost of escaping through 40 cm of sand was calculated to vary between 4.4 and 28.3 kJ per individual, the cost decreasing as the number of individuals in the cohort increased. This represents 11-68% of the energy contained in a hatchling's residual yolk at hatching. The reduced energetic cost associated with large cohorts resulted from both a lower metabolic rate per individual and a shortened nest escape time. We conclude that synchronous digging activity of many hatchlings during nest escape evolved not only to facilitate rapid nest emergence but also to reduce the energetic cost to individuals. © 2016. Published by The Company of Biologists Ltd.

Beach Clean-Up near Historic Beach House

NASA Image and Video Library

2017-04-12

About 50 participants led by NASA Kennedy Space Center's Employee Resource Groups picked up about 20 bags of trash and other large debris along the center's shoreline before turtle-nesting season as a community service. Sea turtle-nesting season begins in about one month. Unlike what might be found along a public beach, all of the debris that litters Kennedy’s restricted beaches washes ashore after being discarded at sea. Of the 72 miles of beach that form the eastern boundary of Brevard County, Florida, about six of those miles line Kennedy.

Climate Change-Induced Shifts in the Hydrological Regime of the Upper Amazon Basin and Its Impacts on Local Eco-Hydrology

NASA Astrophysics Data System (ADS)

Zulkafli, Z. D.; Buytaert, W.; Veliz, C.

2014-12-01

The potential impact of a changing climate on Andean-Amazonian hydrology is an important question for scientists and policymakers alike, because of its implications for local ecosystem services such as water resources availability, river flow regulation, and eco-hydrology. This study presents new projections of climate change impacts on the hydrological regime of the upper Amazon river in Peru, and the consequent effect on two vulnerable species of freshwater turtle populations Podocnemis expansa (Amazon turtle) and Podocnemis unilis (yellow-spotted side neck turtle), which nest on its banks. To do this, the global climate model outputs of radiation, temperature, precipitation, wind, and humidity data from the Coupled Model Inter-comparison Project Phase 5 (CMIP5) are propagated through a hydrological model to simulate changes in river flow. The model consists of a land surface scheme called the Joint-UK Land Environment Simulator (JULES) that is coupled to a distributed river flow routing routine, which also accounts for floodplain attenuation of flood peaks. It is parameterized using a combination of remote sensing (TRMM, MODIS, an Landsat) and ground observational data to reproduce reliably the historical floodplain regime. The climate-induced shifts are inferred from a comparison between the RCP 4.5 and 8.5 projections against the historical scenario. Changes in the 10th and 95th percentile of flows, as well as the distributions in the length of the dry and wet seasons are analysed. These parameters are then used to construct probability models of biologically significant events (BSEs - extreme dry year, extreme wet year and repiquete), which are negative drivers of the turtle-egg ovipositioning, nesting and hatching. The results indicate that the projected increase in wet-season precipitation overcome the increase in evapotranspirative demand from an increase in temperature, resulting in more frequent and longer term flooding that causes a net loss of total turtle-egg counts. Additionally, changes in air and water temperature may alter the male / female ratio of the turtles.

The effect of thermal variance on the phenotype of marine turtle offspring.

PubMed

Horne, C R; Fuller, W J; Godley, B J; Rhodes, K A; Snape, R; Stokes, K L; Broderick, A C

2014-01-01

Temperature can have a profound effect on the phenotype of reptilian offspring, yet the bulk of current research considers the effects of constant incubation temperatures on offspring morphology, with few studies examining the natural thermal variance that occurs in the wild. Over two consecutive nesting seasons, we placed temperature data loggers in 57 naturally incubating clutches of loggerhead sea turtles Caretta caretta and found that greater diel thermal variance during incubation significantly reduced offspring mass, potentially reducing survival of hatchlings during their journey from the nest to offshore waters and beyond. With predicted scenarios of climate change, behavioral plasticity in nest site selection may be key for the survival of ectothermic species, particularly those with temperature-dependent sex determination.

Habitat use and diving behaviour of gravid olive ridley sea turtles under riverine conditions in French Guiana

NASA Astrophysics Data System (ADS)

Chambault, Philippine; Giraudou, Lucie; de Thoisy, Benoît; Bonola, Marc; Kelle, Laurent; Reis, Virginie Dos; Blanchard, Fabian; Le Maho, Yvon; Chevallier, Damien

2017-01-01

The identification of the inter-nesting habitat used by gravid sea turtles has become a crucial factor in their protection. Their aggregation in large groups of individuals during the inter-nesting period exposes them to increased threats to their survival - particularly along the French Guiana shield, where intense legal and illegal fisheries occur. Among the three sea turtle species nesting in French Guiana, the olive ridley appears to have the most generalist diet, showing strong behavioural plasticity according to the environment encountered. The large amounts of sediments that are continuously discharged by the Amazon River create a very unusual habitat for olive ridleys, i.e. turbid waters with low salinity. This study assesses the behavioural adjustments of 20 adult female olive ridleys under such riverine conditions. Individuals were tracked by satellite from Remire-Montjoly rookery in French Guiana using tags that recorded the location and diving parameters of individuals, as well as the immediate environment of the turtles including the in situ temperature and salinity. Data concerning potential preys was provided via collection of epifauna by a trawler. Multiple behavioural shifts were observed in both horizontal and vertical dimensions. During the first half of the inter-nesting season, the turtles moved away from the nesting beach (21.9 ± 24.7 km), performing deeper (12.6 ± 7.4 m) and longer (29.7 ± 21.0 min) dives than during the second half of the period (7.4 ± 7.8 km, 10.4 ± 4.9 m and 25.9 ± 19.3 min). Olive ridleys remained in waters that were warm (range: 26-33 °C) and which fluctuated in terms of salinity (range: 19.5-36.4 psu), in a relatively small estuarine habitat covering 423 km2. If olive ridleys were foraging during this period, the potential preys that might be available were mostly crustaceans (43%) and fish (39%), as expected for the diet of this generalist species during this period. This study highlights the numerous behavioural adaptations of this species in response to the unusual riverine conditions of the French Guiana continental shelf.

Measuring the level of agreement in hematologic and biochemical values between blood sampling sites in leatherback sea turtles (Dermochelys coriacea).

PubMed

Stewart, Kimberly; Mitchell, Mark A; Norton, Terry; Krecek, Rosina C

2012-12-01

Conservation programs to protect endangered sea turtles are being instituted worldwide. A common practice in these programs is to collect blood to evaluate the health of the turtles. Several different venipuncture sites are used to collect blood from sea turtles for hematologic and biochemistry tests, depending on the species. To date, it is unknown what affect venipuncture site may have on sample results. The purpose of this study was to measure the level of agreement between hematologic and biochemistry values collected from the dorsal cervical sinus and the interdigital vein of leatherback (Dermochelys coriacea) sea turtles. Paired heparinized blood samples were obtained from the dorsal cervical sinus and the interdigital vein of 12 adult female nesting leatherback sea turtles on Keys Beach, St. Kitts, West Indies. Even though the sample population was small, the data for each chemistry were normally distributed, except for creatine kinase (CK). There was no significant difference when comparing biochemistry or hematologic values by venipuncture site, except for CK (P = 0.02). The level of agreement between sampling sites was considered good for albumin, calcium, globulin, glucose, packed cell volume, phosphorus, potassium, sodium, total protein, total solids, uric acid, white blood cell count, and all of the individual white cell types, while the level of agreement for aspartate aminotransferase and CK were considered poor. This information, coupled with the fact that the interdigital vein affords a less-invasive procedure, demonstrates that the interdigital vein is an appropriate location to use when establishing a hematologic and biochemical profile for leatherback sea turtles.

Estimating Limit Reference Points for Western Pacific Leatherback Turtles (Dermochelys coriacea) in the U.S. West Coast EEZ

PubMed Central

Curtis, K. Alexandra; Moore, Jeffrey E.; Benson, Scott R.

2015-01-01

Biological limit reference points (LRPs) for fisheries catch represent upper bounds that avoid undesirable population states. LRPs can support consistent management evaluation among species and regions, and can advance ecosystem-based fisheries management. For transboundary species, LRPs prorated by local abundance can inform local management decisions when international coordination is lacking. We estimated LRPs for western Pacific leatherbacks in the U.S. West Coast Exclusive Economic Zone (WCEEZ) using three approaches with different types of information on local abundance. For the current application, the best-informed LRP used a local abundance estimate derived from nest counts, vital rate information, satellite tag data, and fishery observer data, and was calculated with a Potential Biological Removal estimator. Management strategy evaluation was used to set tuning parameters of the LRP estimators to satisfy risk tolerances for falling below population thresholds, and to evaluate sensitivity of population outcomes to bias in key inputs. We estimated local LRPs consistent with three hypothetical management objectives: allowing the population to rebuild to its maximum net productivity level (4.7 turtles per five years), limiting delay of population rebuilding (0.8 turtles per five years), or only preventing further decline (7.7 turtles per five years). These LRPs pertain to all human-caused removals and represent the WCEEZ contribution to meeting population management objectives within a broader international cooperative framework. We present multi-year estimates, because at low LRP values, annual assessments are prone to substantial error that can lead to volatile and costly management without providing further conservation benefit. The novel approach and the performance criteria used here are not a direct expression of the “jeopardy” standard of the U.S. Endangered Species Act, but they provide useful assessment information and could help guide international management frameworks. Given the range of abundance data scenarios addressed, LRPs should be estimable for many other areas, populations, and taxa. PMID:26368557

Estimating Limit Reference Points for Western Pacific Leatherback Turtles (Dermochelys coriacea) in the U.S. West Coast EEZ.

PubMed

Curtis, K Alexandra; Moore, Jeffrey E; Benson, Scott R

2015-01-01

Biological limit reference points (LRPs) for fisheries catch represent upper bounds that avoid undesirable population states. LRPs can support consistent management evaluation among species and regions, and can advance ecosystem-based fisheries management. For transboundary species, LRPs prorated by local abundance can inform local management decisions when international coordination is lacking. We estimated LRPs for western Pacific leatherbacks in the U.S. West Coast Exclusive Economic Zone (WCEEZ) using three approaches with different types of information on local abundance. For the current application, the best-informed LRP used a local abundance estimate derived from nest counts, vital rate information, satellite tag data, and fishery observer data, and was calculated with a Potential Biological Removal estimator. Management strategy evaluation was used to set tuning parameters of the LRP estimators to satisfy risk tolerances for falling below population thresholds, and to evaluate sensitivity of population outcomes to bias in key inputs. We estimated local LRPs consistent with three hypothetical management objectives: allowing the population to rebuild to its maximum net productivity level (4.7 turtles per five years), limiting delay of population rebuilding (0.8 turtles per five years), or only preventing further decline (7.7 turtles per five years). These LRPs pertain to all human-caused removals and represent the WCEEZ contribution to meeting population management objectives within a broader international cooperative framework. We present multi-year estimates, because at low LRP values, annual assessments are prone to substantial error that can lead to volatile and costly management without providing further conservation benefit. The novel approach and the performance criteria used here are not a direct expression of the "jeopardy" standard of the U.S. Endangered Species Act, but they provide useful assessment information and could help guide international management frameworks. Given the range of abundance data scenarios addressed, LRPs should be estimable for many other areas, populations, and taxa.

Genetic structure and natal origins of immature hawksbill turtles (Eretmochelys imbricata) in Brazilian waters.

PubMed

Proietti, Maira C; Reisser, Julia; Marins, Luis Fernando; Rodriguez-Zarate, Clara; Marcovaldi, Maria A; Monteiro, Danielle S; Pattiaratchi, Charitha; Secchi, Eduardo R

2014-01-01

Understanding the connections between sea turtle populations is fundamental for their effective conservation. Brazil hosts important hawksbill feeding areas, but few studies have focused on how they connect with nesting populations in the Atlantic. Here, we (1) characterized mitochondrial DNA control region haplotypes of immature hawksbills feeding along the coast of Brazil (five areas ranging from equatorial to temperate latitudes, 157 skin samples), (2) analyzed genetic structure among Atlantic hawksbill feeding populations, and (3) inferred natal origins of hawksbills in Brazilian waters using genetic, oceanographic, and population size information. We report ten haplotypes for the sampled Brazilian sites, most of which were previously observed at other Atlantic feeding grounds and rookeries. Genetic profiles of Brazilian feeding areas were significantly different from those in other regions (Caribbean and Africa), and a significant structure was observed between Brazilian feeding grounds grouped into areas influenced by the South Equatorial/North Brazil Current and those influenced by the Brazil Current. Our genetic analysis estimates that the studied Brazilian feeding aggregations are mostly composed of animals originating from the domestic rookeries Bahia and Pipa, but some contributions from African and Caribbean rookeries were also observed. Oceanographic data corroborated the local origins, but showed higher connection with West Africa and none with the Caribbean. High correlation was observed between origins estimated through genetics/rookery size and oceanographic/rookery size data, demonstrating that ocean currents and population sizes influence haplotype distribution of Brazil's hawksbill populations. The information presented here highlights the importance of national conservation strategies and international cooperation for the recovery of endangered hawksbill turtle populations.

Genetic Structure and Natal Origins of Immature Hawksbill Turtles (Eretmochelys imbricata) in Brazilian Waters

PubMed Central

Proietti, Maira C.; Reisser, Julia; Marins, Luis Fernando; Rodriguez-Zarate, Clara; Marcovaldi, Maria A.; Monteiro, Danielle S.; Pattiaratchi, Charitha; Secchi, Eduardo R.

2014-01-01

Understanding the connections between sea turtle populations is fundamental for their effective conservation. Brazil hosts important hawksbill feeding areas, but few studies have focused on how they connect with nesting populations in the Atlantic. Here, we (1) characterized mitochondrial DNA control region haplotypes of immature hawksbills feeding along the coast of Brazil (five areas ranging from equatorial to temperate latitudes, 157 skin samples), (2) analyzed genetic structure among Atlantic hawksbill feeding populations, and (3) inferred natal origins of hawksbills in Brazilian waters using genetic, oceanographic, and population size information. We report ten haplotypes for the sampled Brazilian sites, most of which were previously observed at other Atlantic feeding grounds and rookeries. Genetic profiles of Brazilian feeding areas were significantly different from those in other regions (Caribbean and Africa), and a significant structure was observed between Brazilian feeding grounds grouped into areas influenced by the South Equatorial/North Brazil Current and those influenced by the Brazil Current. Our genetic analysis estimates that the studied Brazilian feeding aggregations are mostly composed of animals originating from the domestic rookeries Bahia and Pipa, but some contributions from African and Caribbean rookeries were also observed. Oceanographic data corroborated the local origins, but showed higher connection with West Africa and none with the Caribbean. High correlation was observed between origins estimated through genetics/rookery size and oceanographic/rookery size data, demonstrating that ocean currents and population sizes influence haplotype distribution of Brazil's hawksbill populations. The information presented here highlights the importance of national conservation strategies and international cooperation for the recovery of endangered hawksbill turtle populations. PMID:24558419

Geomagnetic imprinting: A unifying hypothesis of long-distance natal homing in salmon and sea turtles.

PubMed

Lohmann, Kenneth J; Putman, Nathan F; Lohmann, Catherine M F

2008-12-09

Several marine animals, including salmon and sea turtles, disperse across vast expanses of ocean before returning as adults to their natal areas to reproduce. How animals accomplish such feats of natal homing has remained an enduring mystery. Salmon are known to use chemical cues to identify their home rivers at the end of spawning migrations. Such cues, however, do not extend far enough into the ocean to guide migratory movements that begin in open-sea locations hundreds or thousands of kilometers away. Similarly, how sea turtles reach their nesting areas from distant sites is unknown. However, both salmon and sea turtles detect the magnetic field of the Earth and use it as a directional cue. In addition, sea turtles derive positional information from two magnetic elements (inclination angle and intensity) that vary predictably across the globe and endow different geographic areas with unique magnetic signatures. Here we propose that salmon and sea turtles imprint on the magnetic field of their natal areas and later use this information to direct natal homing. This novel hypothesis provides the first plausible explanation for how marine animals can navigate to natal areas from distant oceanic locations. The hypothesis appears to be compatible with present and recent rates of field change (secular variation); one implication, however, is that unusually rapid changes in the Earth's field, as occasionally occur during geomagnetic polarity reversals, may affect ecological processes by disrupting natal homing, resulting in widespread colonization events and changes in population structure.

Geomagnetic imprinting: A unifying hypothesis of long-distance natal homing in salmon and sea turtles

PubMed Central

Lohmann, Kenneth J.; Putman, Nathan F.; Lohmann, Catherine M. F.

2008-01-01

Several marine animals, including salmon and sea turtles, disperse across vast expanses of ocean before returning as adults to their natal areas to reproduce. How animals accomplish such feats of natal homing has remained an enduring mystery. Salmon are known to use chemical cues to identify their home rivers at the end of spawning migrations. Such cues, however, do not extend far enough into the ocean to guide migratory movements that begin in open-sea locations hundreds or thousands of kilometers away. Similarly, how sea turtles reach their nesting areas from distant sites is unknown. However, both salmon and sea turtles detect the magnetic field of the Earth and use it as a directional cue. In addition, sea turtles derive positional information from two magnetic elements (inclination angle and intensity) that vary predictably across the globe and endow different geographic areas with unique magnetic signatures. Here we propose that salmon and sea turtles imprint on the magnetic field of their natal areas and later use this information to direct natal homing. This novel hypothesis provides the first plausible explanation for how marine animals can navigate to natal areas from distant oceanic locations. The hypothesis appears to be compatible with present and recent rates of field change (secular variation); one implication, however, is that unusually rapid changes in the Earth's field, as occasionally occur during geomagnetic polarity reversals, may affect ecological processes by disrupting natal homing, resulting in widespread colonization events and changes in population structure. PMID:19060188

Bahamas connection: residence areas selected by breeding female loggerheads tagged in Dry Tortugas National Park, USA

USGS Publications Warehouse

Hart, Kristen M.; Sartain-Iverson, Autumn R.; Fujisaki, Ikuko

2015-01-01

We demonstrate a previously unknown link between Dry Tortugas nesting beaches and Bahamas residence areas; 17/39 (43.6%) of nesting loggerheads tagged in and tracked from the Dry Tortugas take up residence at sites in the Bahamas. Residence area estimates for these turtles were similar in size to previous foraging area estimates for two turtles tracked to the Bahamas in other studies. We show inter-annual residence area repeatability, and that residence areas of different individuals generally did not overlap. We suggest that these loggerheads possibly establish territories.

Changes in gonadal and adrenal steroid levels in the leatherback sea turtle (Dermochelys coriacea) during the nesting cycle.

PubMed

Rostal, D C; Grumbles, J S; Palmer, K S; Lance, V A; Spotila, J R; Paladino, F V

2001-05-01

The reproductive endocrinology of nesting leatherback turtles (Dermochelys coriacea) was studied during the 1996-1997 and 1997-1998 nesting seasons at Los Baulas National Park, Playa Grande, Costa Rica. Blood samples were collected from nesting females throughout the season. Females were observed to nest up to 10 times during the nesting season. Plasma steroids were measured by radioimmunoassay and total plasma calcium was measured by flame atomic absorption spectrophotometry. Plasma testosterone and plasma estradiol levels declined throughout the nesting cycle of the female. Testosterone declined from a mean of 10.18 +/- 0.77 ng/ml at the beginning of the nesting cycle to 1.73 +/- 0.34 ng/ml at the end of the nesting cycle. Estradiol declined in a similar manner, ranging from a mean of 190.95 +/- 16.80 pg/ml at the beginning of the nesting cycle to 76.52 +/- 12.66 pg/ml at the end of the nesting cycle. Plasma progesterone and total calcium levels were relatively constant throughout the nesting cycle. Lack of fluctuation of total calcium levels, ranging from a mean high of 97.46 +/- 11.37 microg/ml to a mean low of 64.85 +/- 11.20 microg/ml, further suggests that vitellogenesis is complete prior to the arrival of the female at the nesting beach. Clutch size (both yolked and yolkless eggs) did not vary over the course of the nesting cycle. Copyright 2001 Academic Press.

Female turtles from hot nests: is it duration of incubation or proportion of development at high temperatures that matters?

PubMed

Georges, Arthur

1989-11-01

Mean daily temperature in natural nests of freshwater turtles with temperature-dependent sex determination is known to be a poor predictor of hatchling sex ratios when nest temperatures fluctuate. To account for this, a model was developed on the assumption that females will emerge from eggs when more than half of embryonic development occurs above the threshold temperature for sex determination rather than from eggs that spend more than half their time above the threshold. The model is consistent with previously published data and in particular explains the phenomenon whereby the mean temperature that best distinguishes between male and female nests decreases with increasing variability in nest temperature. The model, if verified by controlled experiments, has important implications for our understanding of temperature-dependent sex determination in natural nests. Both mean nest temperature and "hours spent above the threshold" will be poor predictors of hatchling sex ratios. Studies designed to investigate latitudinal trends and inter-specific differences in the threshold temperature will need to consider latitudinal and inter-specific variation in the magnitude of diel fluctuations in nest temperature, and variation in factors influencing the magnitude of those fluctuations, such as nest depth. Furthermore, any factor that modifies the relationship between developmental rate and temperature can be expected to influence hatchling sex ratios in natural nests, especially when nest temperatures are close to the threshold.

δ13C and d15N in the endangered Kemp’s ridley sea turtle Lepidochelys kempii after the Deepwater Horizon oil spill

USGS Publications Warehouse

Reich, Kimberly J.; López-Castro, Melania C.; Shaver, Donna J.; Iseton, Claire; Hart, Kristen M.; Hooper, Michael J.; Schmitt, Christopher J.

2017-01-01

The Deepwater Horizon explosion in April 2010 and subsequent oil spill released 3.19 × 106 barrels (5.07 × 108 L) of MC252 crude oil into important foraging areas of the endangered Kemp’s ridley sea turtle Lepidochelys kempii (Lk) in the northern Gulf of Mexico (GoM). We measured δ13C and δ15N in scute biopsy samples from 33 Lk nesting in Texas during 2010–-12. Of these, 27 were equipped with satellite transmitters and were tracked to traditional foraging areas in the northern GoM after the spill. Differences in δ13C between the oldest and newest scute layers from 2010 nesters were not significantly different, but δ13C in the newest layers from 2011 and 2012 nesters was significantly lower compared to 2010. δ15N differences were not statistically significant. Collectively, the stable isotope and tracking data indicate that the lower δ13C values reflect the incorporation of oil rather than changes in diet or foraging area. Discriminant analysis indicated that 51.5% of the turtles sampled had isotope signatures indicating oil exposure. Growth of the Lk population slowed in the years following the spill. The involvement of oil exposure in recent population trends is unknown, but long-term effects may not be evident for many years. Our results indicate that C isotope signatures in scutes may be useful biomarkers of sea turtle exposure to oil.

Maternal transfer of chlorinated contaminants in the leatherback turtles, Dermochelys coriacea, nesting in French Guiana.

PubMed

Guirlet, Elodie; Das, Krishna; Thomé, Jean-Pierre; Girondot, Marc

2010-04-01

We examined the maternal transfer of organochlorine contaminants (OCs), pesticides (DDTS and HCHs) and polychlorinated biphenyls (PCBs), and the temporal variation of blood and eggs concentrations from 38 leatherback turtles (Dermochelys coriacea) nesting in French Guiana. PCBs were found to be the dominant OCs with respective mean concentrations of 55.14 ng g(-1) lipid-mass for egg and 1.26 ng mL(-1) wet-mass for blood. OC concentrations were lower than concentrations measured in other marine turtles which might be due to the lower trophic position (diet based on gelatinous zooplankton) and to the location of their foraging and nesting grounds. All OCs detected in leatherback blood were detected in eggs, suggesting a maternal transfer of OCs. This transfer was shown to depend on female blood concentration for SigmaDDTs and for the most prevalent PCB congeners, since significant relationships were found between paired blood-egg concentrations. During the nesting season, OC concentrations in eggs and the percentage of lipid in eggs were found to decline in successive clutches, highlighting a process of offloading from females to their eggs and a decreasing investment of lipid from females into their clutches. OCs in eggs tended to be higher in females spending 3 years in the foraging grounds between two nesting seasons than in those spending 2 years, suggesting an impact of time spacing two breeding seasons, called remigration interval, and of location of the foraging grounds. 2010 Elsevier Ltd. All rights reserved.

The western pond turtle (Clemmys marmorata) in the Mojave River, California, USA: Highly adapted survivor or tenuous relict?

USGS Publications Warehouse

Lovich, J.; Meyer, K.

2002-01-01

Aspects of the ecology of populations of the western pond turtle Clemmys marmorata were investigated in the Mojave River of the central Mojave Desert, California, U.S.A. One population occupied man-made ponds and the other occurred in natural ponds in the flood plain of the Mojave River. Both habitats are severely degraded as a result of ground water depletion from human activities along the river and one is infested with the exotic shrub saltcedar Tamarix ramosissima. Mean female carapace length (CL) was significantly greater (14.4 cm) than that of males (13.7 cm). Live juveniles were not detected during the period of study. Shelled eggs were visible in X-radiographs from 26 May to 14 July. Mean clutch size was 4.46 and ranged from 3 to 6 eggs. Clutch size did not vary between 1998 and 1999 but was significantly correlated with CL for both years combined, increasing at the rate of 0.548 eggs/cm CL. Gravid female CL ranged from 13.3-16.0 cm. Some females nested in both years. Mean X-ray egg width (21.8 mm) was not significantly correlated with CL or clutch size. X-ray egg width differed more among clutches than within, whether including CL as a co-variate or not. Nesting migrations occurred from 6 June to 8 July with minimum round trip distances ranging from 17.5-585 m with a mean of 195 m. Mean estimated time of departure as measured at the drift fence was 18:13. Most females returned to the ponds in the early morning. Nesting migrations required females to be out of the water for estimated periods of 0.83 to 86 h. The destination of nesting females was typically fluvial sand bars in the channel of the dry riverbed. Overall, the ecology of C. marmorata in the Mojave River is very similar to that reported for populations in less severe habitats along the west coast of the United States. Notable exceptions include long nesting migrations to sandbars in the dry river channel, a possible result of human modifications to the environment, and an apparent lack of terrestrial overwintering behaviour in Mojave River populations. The general similarity of desert and coastal populations is possibly a reflection of their recent geographic separation. Overall, populations in the Mojave River exhibit few obvious adaptations to living in the desert and are considered to be tenuous relicts of the Pleistocene. The small size and tenuous status of these populations suggests that immediate conservation action is needed, including establishment of satellite populations as a hedge against extirpation.

Multinational tagging efforts illustrate regional scale of distribution and threats for east pacific green turtles (Chelonia mydas agassizii).

PubMed

Hart, Catherine E; Blanco, Gabriela S; Coyne, Michael S; Delgado-Trejo, Carlos; Godley, Brendan J; Jones, T Todd; Resendiz, Antonio; Seminoff, Jeffrey A; Witt, Matthew J; Nichols, Wallace J

2015-01-01

To further describe movement patterns and distribution of East Pacific green turtles (Chelonia mydas agassizii) and to determine threat levels for this species within the Eastern Pacific. In order to do this we combined published data from existing flipper tagging and early satellite tracking studies with data from an additional 12 satellite tracked green turtles (1996-2006). Three of these were tracked from their foraging grounds in the Gulf of California along the east coast of the Baja California peninsula to their breeding grounds in Michoacán (1337-2928 km). In addition, three post-nesting females were satellite tracked from Colola beach, Michoacán to their foraging grounds in southern Mexico and Central America (941.3-3020 km). A further six turtles were tracked in the Gulf of California within their foraging grounds giving insights into the scale of ranging behaviour. Turtles undertaking long-distance migrations showed a tendency to follow the coastline. Turtles tracked within foraging grounds showed that foraging individuals typically ranged up to 691.6 km (maximum) from release site location. Additionally, we carried out threat analysis (using the cumulative global human impact in the Eastern Pacific) clustering pre-existing satellite tracking studies from Galapagos, Costa Rica, and data obtained from this study; this indicated that turtles foraging and nesting in Central American waters are subject to the highest anthropogenic impact. Considering that turtles from all three rookeries were found to migrate towards Central America, it is highly important to implement conservation plans in Central American coastal areas to ensure the survival of the remaining green turtles in the Eastern Pacific. Finally, by combining satellite tracking data from this and previous studies, and data of tag returns we created the best available distributional patterns for this particular sea turtle species, which emphasized that conservation measures in key areas may have positive consequences on a regional scale.

Multinational Tagging Efforts Illustrate Regional Scale of Distribution and Threats for East Pacific Green Turtles (Chelonia mydas agassizii)

PubMed Central

Hart, Catherine E.; Blanco, Gabriela S.; Coyne, Michael S.; Delgado-Trejo, Carlos; Godley, Brendan J.; Jones, T. Todd; Resendiz, Antonio; Seminoff, Jeffrey A.; Witt, Matthew J.; Nichols, Wallace J.

2015-01-01

To further describe movement patterns and distribution of East Pacific green turtles (Chelonia mydas agassizii) and to determine threat levels for this species within the Eastern Pacific. In order to do this we combined published data from existing flipper tagging and early satellite tracking studies with data from an additional 12 satellite tracked green turtles (1996-2006). Three of these were tracked from their foraging grounds in the Gulf of California along the east coast of the Baja California peninsula to their breeding grounds in Michoacán (1337-2928 km). In addition, three post-nesting females were satellite tracked from Colola beach, Michoacán to their foraging grounds in southern Mexico and Central America (941.3-3020 km). A further six turtles were tracked in the Gulf of California within their foraging grounds giving insights into the scale of ranging behaviour. Turtles undertaking long-distance migrations showed a tendency to follow the coastline. Turtles tracked within foraging grounds showed that foraging individuals typically ranged up to 691.6 km (maximum) from release site location. Additionally, we carried out threat analysis (using the cumulative global human impact in the Eastern Pacific) clustering pre-existing satellite tracking studies from Galapagos, Costa Rica, and data obtained from this study; this indicated that turtles foraging and nesting in Central American waters are subject to the highest anthropogenic impact. Considering that turtles from all three rookeries were found to migrate towards Central America, it is highly important to implement conservation plans in Central American coastal areas to ensure the survival of the remaining green turtles in the Eastern Pacific. Finally, by combining satellite tracking data from this and previous studies, and data of tag returns we created the best available distributional patterns for this particular sea turtle species, which emphasized that conservation measures in key areas may have positive consequences on a regional scale. PMID:25646803

Fidelity and over-wintering of sea turtles.

PubMed

Broderick, Annette C; Coyne, Michael S; Fuller, Wayne J; Glen, Fiona; Godley, Brendan J

2007-06-22

While fidelity to breeding sites is well demonstrated in marine turtles, emerging knowledge of migratory routes and key foraging sites is of limited conservation value unless levels of fidelity can be established. We tracked green (Chelonia mydas, n=10) and loggerhead (Caretta caretta, n=10) turtles during their post-nesting migration from the island of Cyprus to their foraging grounds. After intervals of 2-5 years, five of these females were recaptured at the nesting beach and tracked for a second migration. All five used highly similar migratory routes to return to the same foraging and over-wintering areas. None of the females visited other foraging habitats over the study period (units lasted on average 305 days; maximum, 1356 days), moving only to deeper waters during the winter months where they demonstrated extremely long resting dives of up to 10.2h (the longest breath-holding dive recorded for a marine vertebrate). High levels of fidelity and the relatively discrete nature of the home ranges demonstrate that protection of key migratory pathways, foraging and over-wintering sites can serve as an important tool for the future conservation of marine turtles.

Measuring behavioral responses of sea turtles, saltwater crocodiles, and crested terns to drone disturbance to define ethical operating thresholds.

PubMed

Bevan, Elizabeth; Whiting, Scott; Tucker, Tony; Guinea, Michael; Raith, Andrew; Douglas, Ryan

2018-01-01

Drones are being increasingly used in innovative ways to enhance environmental research and conservation. Despite their widespread use for wildlife studies, there are few scientifically justified guidelines that provide minimum distances at which wildlife can be approached to minimize visual and auditory disturbance. These distances are essential to ensure that behavioral and survey data have no observer bias and form the basis of requirements for animal ethics and scientific permit approvals. In the present study, we documented the behaviors of three species of sea turtle (green turtles, Chelonia mydas, flatback turtles, Natator depressus, hawksbill turtles, Eretmochelys imbricata), saltwater crocodiles (Crocodylus porosus), and crested terns (Thalasseus bergii) in response to a small commercially available (1.4 kg) multirotor drone flown in Northern Territory and Western Australia. Sea turtles in nearshore waters off nesting beaches or in foraging habitats exhibited no evasive behaviors (e.g. rapid diving) in response to the drone at or above 20-30 m altitude, and at or above 10 m altitude for juvenile green and hawksbill turtles foraging on shallow, algae-covered reefs. Adult female flatback sea turtles were not deterred by drones flying forward or stationary at 10 m altitude when crawling up the beach to nest or digging a body pit or egg chamber. In contrast, flyovers elicited a range of behaviors from crocodiles, including minor, lateral head movements, fleeing, or complete submergence when a drone was present below 50 m altitude. Similarly, a colony of crested terns resting on a sand-bank displayed disturbance behaviors (e.g. flight response) when a drone was flown below 60 m altitude. The current study demonstrates a variety of behavioral disturbance thresholds for diverse species and should be considered when establishing operating conditions for drones in behavioral and conservation studies.

Migration, Foraging, and Residency Patterns for Northern Gulf Loggerheads: Implications of Local Threats and International Movements

PubMed Central

Hart, Kristen M.; Lamont, Margaret M.; Sartain, Autumn R.; Fujisaki, Ikuko

2014-01-01

Northern Gulf of Mexico (NGoM) loggerheads (Caretta caretta) make up one of the smallest subpopulations of this threatened species and have declining nest numbers. We used satellite telemetry and a switching state-space model to identify distinct foraging areas used by 59 NGoM loggerheads tagged during 2010–2013. We tagged turtles after nesting at three sites, 1 in Alabama (Gulf Shores; n = 37) and 2 in Florida (St. Joseph Peninsula; n = 20 and Eglin Air Force Base; n = 2). Peak migration time was 22 July to 9 August during which >40% of turtles were in migration mode; the mean post-nesting migration period was 23.0 d (±13.8 d SD). After displacement from nesting beaches, 44 turtles traveled to foraging sites where they remained resident throughout tracking durations. Selected foraging locations were variable distances from tagging sites, and in 5 geographic regions; no turtles selected foraging sites outside the Gulf of Mexico (GoM). Foraging sites delineated using 50% kernel density estimation were located a mean distance of 47.6 km from land and in water with mean depth of −32.5 m; other foraging sites, delineated using minimum convex polygons, were located a mean distance of 43.0 km from land and in water with a mean depth of −24.9 m. Foraging sites overlapped with known trawling activities, oil and gas extraction activities, and the footprint of surface oiling during the 2010 Deepwater Horizon oil spill (n = 10). Our results highlight the year-round use of habitats in the GoM by loggerheads that nest in the NGoM. Our findings indicate that protection of females in this subpopulation requires both international collaborations and management of threats that spatially overlap with distinct foraging habitats. PMID:25076053

Canaveral Harbor, Florida, Integrated Section 203 Navigation Study Report and Final Environmental Assessment. Volume 1

DTIC Science & Technology

2012-10-01

source of nutrition for juvenile green sea turtles. The beaches and spoil areas may also be utilized by nesting and foraging shorebirds including the...include the upper west coast of Florida, the northwestern coast of the Yucatan Peninsula, the south coast of Cuba, the Mosquito Coast of Nicaragua...1997. Foraging ecology and nutrition of sea turtles. Pages 199-233 In: Lutz, P.L. and J.A. Musick, eds., The Biology of Sea Turtles. CRC Press, New

Effects of biotic and abiotic factors on the oxygen content of green sea turtle nests during embryogenesis.

PubMed

Chen, Chiu-Lin; Wang, Chun-Chun; Cheng, I-Jiunn

2010-10-01

Several biotic and abiotic factors can influence nest oxygen content during embryogenesis. Several of these factors were determined during each developmental stage of green sea turtle embryos on Wan-an Island, Penghu Archipelago, Taiwan. We examined oxygen content in 7 nests in 2007 and 11 in 2008. Oxygen in the adjacent sand, total and viable clutch sizes, air, sand and nest temperatures, and sand characters of each nest were also determined. Oxygen content was lower in late stages than in the early and middle stages. It was also lower in the middle layer than in the upper and bottom layers. Nest temperature showed opposite trends, reaching its maximum value in late stages of development. Nest oxygen content was influenced by fraction of viable eggs, total clutch sizes, sand temperatures, maximum nest temperature and maximum change in the nest temperature during incubation. Clutch size during embryogenesis was the most influential factor overall. However, the major influential factors were different for different developmental stages. In the first half of the incubation, the development rate was low, and the change in the nest oxygen content was influenced mainly by the clutch size. During the second half, the rapid embryonic development rate became the dominant factor, and hatchling activities caused even greater oxygen consumption during the last stage of development.

Stable Isotope Tracking of Endangered Sea Turtles: Validation with Satellite Telemetry and δ15N Analysis of Amino Acids

PubMed Central

Seminoff, Jeffrey A.; Benson, Scott R.; Arthur, Karen E.; Eguchi, Tomoharu; Dutton, Peter H.; Tapilatu, Ricardo F.; Popp, Brian N.

2012-01-01

Effective conservation strategies for highly migratory species must incorporate information about long-distance movements and locations of high-use foraging areas. However, the inherent challenges of directly monitoring these factors call for creative research approaches and innovative application of existing tools. Highly migratory marine species, such as marine turtles, regularly travel hundreds or thousands of kilometers between breeding and feeding areas, but identification of migratory routes and habitat use patterns remains elusive. Here we use satellite telemetry in combination with compound-specific isotope analysis of amino acids to confirm that insights from bulk tissue stable isotope analysis can reveal divergent migratory strategies and within-population segregation of foraging groups of critically endangered leatherback sea turtles (Dermochelys coriacea) across the Pacific Ocean. Among the 78 turtles studied, we found a distinct dichotomy in δ15N values of bulk skin, with distinct “low δ15N” and “high δ15N” groups. δ15N analysis of amino acids confirmed that this disparity resulted from isotopic differences at the base of the food chain and not from differences in trophic position between the two groups. Satellite tracking of 13 individuals indicated that their bulk skin δ15N value was linked to the particular foraging region of each turtle. These findings confirm that prevailing marine isoscapes of foraging areas can be reflected in the isotopic compositions of marine turtle body tissues sampled at nesting beaches. We use a Bayesian mixture model to show that between 82 and 100% of the 78 skin-sampled turtles could be assigned with confidence to either the eastern Pacific or western Pacific, with 33 to 66% of all turtles foraging in the eastern Pacific. Our forensic approach validates the use of stable isotopes to depict leatherback turtle movements over broad spatial ranges and is timely for establishing wise conservation efforts in light of this species’ imminent risk of extinction in the Pacific. PMID:22666354

Stable isotope tracking of endangered sea turtles: validation with satellite telemetry and δ15N analysis of amino acids.

PubMed

Seminoff, Jeffrey A; Benson, Scott R; Arthur, Karen E; Eguchi, Tomoharu; Dutton, Peter H; Tapilatu, Ricardo F; Popp, Brian N

2012-01-01

Effective conservation strategies for highly migratory species must incorporate information about long-distance movements and locations of high-use foraging areas. However, the inherent challenges of directly monitoring these factors call for creative research approaches and innovative application of existing tools. Highly migratory marine species, such as marine turtles, regularly travel hundreds or thousands of kilometers between breeding and feeding areas, but identification of migratory routes and habitat use patterns remains elusive. Here we use satellite telemetry in combination with compound-specific isotope analysis of amino acids to confirm that insights from bulk tissue stable isotope analysis can reveal divergent migratory strategies and within-population segregation of foraging groups of critically endangered leatherback sea turtles (Dermochelys coriacea) across the Pacific Ocean. Among the 78 turtles studied, we found a distinct dichotomy in δ(15)N values of bulk skin, with distinct "low δ(15)N" and "high δ(15)N" groups. δ(15)N analysis of amino acids confirmed that this disparity resulted from isotopic differences at the base of the food chain and not from differences in trophic position between the two groups. Satellite tracking of 13 individuals indicated that their bulk skin δ(15)N value was linked to the particular foraging region of each turtle. These findings confirm that prevailing marine isoscapes of foraging areas can be reflected in the isotopic compositions of marine turtle body tissues sampled at nesting beaches. We use a Bayesian mixture model to show that between 82 and 100% of the 78 skin-sampled turtles could be assigned with confidence to either the eastern Pacific or western Pacific, with 33 to 66% of all turtles foraging in the eastern Pacific. Our forensic approach validates the use of stable isotopes to depict leatherback turtle movements over broad spatial ranges and is timely for establishing wise conservation efforts in light of this species' imminent risk of extinction in the Pacific.

[Reproductive activity of Chelonia mydas (Testudines: Cheloniidae) in Isla de Aves, Venezuela (2001-2008)].

PubMed

Vera, Vicente; Buitrago, Joaquín

2012-06-01

The second major nesting-site for green turtles in the Caribbean is Isla de Aves, an island protected as a wildlife refuge since 1972, located at 650km Northeast from La Guaira, Venezuela. In this island, the nesting population monitoring started in 1972 and in a more continuous way after 1978, when a Scientific-Naval Station was established and scientific observations started. Since historical data show that female captures had severely affected population levels in this island before 1978, this study aim to describe recent reproductive activities. For this, during the nesting seasons of 2001-2002 and 2005-2008, nesting females were measured and tagged using metal flipper tags. A total of 458 nights were sampled observing 5 154 female emergences, with a maximum of 53 in a single night. Non-observed emergences were calculated fitting the temporal distribution of observed emergences to a normal curve. Total emergences estimated varied from X=637.1+/-106.6 in 2001 to X =2 853+/-42.5 in 2008 (ANOVA F(6.5df)=60.37, p<0.0001). Internesting interval in the same season was estimated in X=10.71+/-1.32 days. Clutch frequency in a nesting season was calculated as X=1.71+/-1.6 times per female and season. Estimated number of nesting females per year varied from X=373+/-12.5 females in 2001 to X=l 669+/-56.1 females in 2008 (ANOVA F 55.6df)=89.42, p<0.0001); with a positive and significant trend (r=0.842, p=0.036). Results show that nesting females numbers are increasing. We suggest that the protection of the nesting area for more than 30 years, has contributed with this population increase.

[False eggs (SAGs) facilitate social post-hatching emergence behaviour in Leatherback turtles Dermochelys coriacea (Testudines: Dermochelyidae) nests].

PubMed

Patiño-Martinez, Juan; Marco, Adolfo; Quiñones, Liliana; Calabuig, Cecilia P

2010-09-01

Hatchling emergence to the beach surface from deep sand nests occurs without parental care. Social behaviour among siblings is crucial to overcome this first challenge in sea turtles life. This study, carried out at the Caribbean coast of Colombia, describes the emergence social behaviour of hatchlings from eight nests, and assess the nests translocation effects on temporal patterns of emergence. For the first time, we propose that space released by dehydration of shelled albumen globes (SAGs) at the top of the clutch, might be a reproductive advantage, while facilitating neonates to group together in a very limited space, and favouring the synchrony of emergence. The mean time of groups emergence was of 3.3 days, varying between 1 and 6 days. We found that relocation of the nests did not significantly affect the temporal pattern of emergence, which was mainly nocturnal (77.7% of natural nests and 81.7% of translocated ones). The maximum number of emergences to the surface occurred at the lowest air temperatures (22:00h-06:00h). The selective advantage of this pattern is probably related to the greater rate of predation and mortality by hyperthermia observed during the day.

Prediction of supratidal Zones as turtle nesting sites using remote sensing and geographic information system, a case study in Pacitan, Southern Java Sea

NASA Astrophysics Data System (ADS)

Darmawan, A.; Saputra, D. K.; Wiadnya, D. G. R.; Gusmida, A. M.

2018-04-01

Turtles, the most threatened coastal-marine fauna, are protected through both national and global regulations. However, many of their nesting sites have been degraded in the past years. Completing natal homing, adult females emerged at night to lay-down eggs in the upper intertidal and supra-tidal zone of sandy beach from where they hatched. This study explained coastal topology of beaches usually used for nesting sites, covering 117 km coastline at Pacitan Regency, Southern Java Sea. The shift in beach morphology through times was figured out based on Landsat 8 and Sentinel 2a satellite imagery and remote sensing (GIS methods). This was combined with in-situ data on current coastline features, slope, and tide variations. Results showed a typical sandy beach, called Taman Ria Beach, a long time identified as nesting site for Lepidochelys olivacea, locally named as Penyu Lekang. Also, there was approximatelly 3.49 ha of supratidal area predicted in Taman Ria Beach according this study

Mapping risk for nest predation on a barrier island

USGS Publications Warehouse

Hackney, Amanda D.; Baldwin, Robert F.; Jodice, Patrick G.R.

2013-01-01

Barrier islands and coastal beach systems provide nesting habitat for marine and estuarine turtles. Densely settled coastal areas may subsidize nest predators. Our purpose was to inform conservation by providing a greater understanding of habitat-based risk factors for nest predation, for an estuarine turtle. We expected that habitat conditions at predated nests would differ from random locations at two spatial extents. We developed and validated an island-wide model for the distribution of predated Diamondback terrapin nests using locations of 198 predated nests collected during exhaustive searches at Fisherman Island National Wildlife Refuge, USA. We used aerial photographs to identify all areas of possible nesting habitat and searched each and surrounding environments for nests, collecting location and random-point microhabitat data. We built models for the probability of finding a predated nest using an equal number of random points and validated them with a reserve set (N = 67). Five variables in 9 a priori models were used and the best selected model (AIC weight 0.98) reflected positive associations with sand patches near marshes and roadways. Model validation had an average capture rate of predated nests of 84.14 % (26.17–97.38 %, Q1 77.53 %, median 88.07 %, Q3 95.08 %). Microhabitat selection results suggest that nests placed at the edges of sand patches adjacent to upland shrub/forest and marsh systems are vulnerable to predation. Forests and marshes provide cover and alternative resources for predators and roadways provide access; a suggestion is to focus nest protection efforts on the edges of dunes, near dense vegetation and roads.

Survey of Florida green turtles for exposure to a disease-associated herpesvirus.

PubMed

Coberley, S S; Herbst, L H; Ehrhart, L M; Bagley, D A; Hirama, S; Jacobson, E R; Klein, P A

2001-12-05

A recently developed enzyme-linked immunosorbent assay (ELISA) was used to assess exposure of Florida wild green turtles Chelonia mydas to LETV, the herpesvirus associated with lung-eye-trachea disease (LETD). Plasma samples from 329 wild juvenile green turtles netted in the Indian River lagoon, along the Sebastian reef, or in the Trident basin (Indian River and Brevard Counties, Florida) were tested by ELISA for the presence of antibodies to LETV. Plasma samples from 180 wild juvenile green turtles were tested from these study sites to compare the prevalence of anti-LETV antibodies. While some plasma samples from each site contained anti-LETV antibodies (confirmed by Western blot analysis), plasma samples collected from the Indian River lagoon had statistically higher optical density values measured in the ELISA. No statistical differences were observed when these same plasma samples were analyzed for changes in the level of anti-LETV antibodies over 3 years (1997, 1998, and 1999). To explore the relationship between anti-LETV antibodies and fibropapillomatosis (FP), plasma from 133 green turtles scored for fibropapilloma tumor severity were tested by ELISA. There was no correlation between tumor severity and the presence of antibodies against LETV. Additional plasma samples collected from 16 tagged green turtles captured and sampled more than once (recaptures) were also tested to monitor antibody levels to LETV relative to the FP status of individual turtles over time. Again there was no clear relationship between FP tumor status and the presence of antibodies to LETV. Finally, ELISA tests on plasma from 13 nesting female turtles (9 green and 4 loggerhead) revealed high levels of anti-LETV antibodies in 11 individuals, including 2 loggerhead turtles. These results provide strong evidence that wild Florida green turtle populations at these 3 study sites are exposed to LETV or a closely related virus and that loggerhead turtles may be exposed as well. Based on a cutoff optical density value of 0.310, 71 out of the 329 wild Florida green turtles tested were seropositive for LETV antibodies (seroprevalence = 21.6%). In addition, no relationship between FP tumor severity or status and the presence of anti-LETV antibodies was found, further supporting the hypothesis that LETV and the FP-associated herpesvirus (FPHV) are separate infections of marine turtles.

Nuclear markers reveal a complex introgression pattern among marine turtle species on the Brazilian coast.

PubMed

Vilaça, Sibelle T; Vargas, Sarah M; Lara-Ruiz, Paula; Molfetti, Érica; Reis, Estéfane C; Lôbo-Hajdu, Gisele; Soares, Luciano S; Santos, Fabrício R

2012-09-01

Surprisingly, a high frequency of interspecific sea turtle hybrids has been previously recorded in a nesting site along a short stretch of the Brazilian coast. Mitochondrial DNA data indicated that as much as 43% of the females identified as Eretmochelys imbricata are hybrids in this area (Bahia State of Brazil). It is a remarkable find, because most of the nesting sites surveyed worldwide, including some in northern Brazil, presents no hybrids, and rare Caribbean sites present no more than 2% of hybrids. Thus, a detailed understanding of the hybridization process is needed to evaluate natural or anthropogenic causes of this regional phenomenon in Brazil, which could be an important factor affecting the conservation of this population. We analysed a set of 12 nuclear markers to investigate the pattern of hybridization involving three species of sea turtles: hawksbill (E. imbricata), loggerhead (Caretta caretta) and olive ridley (Lepidochelys olivacea). Our data indicate that most of the individuals in the crossings L. olivacea × E. imbricata and L. olivacea × C. caretta are F1 hybrids, whereas C. caretta × E. imbricata crossings present F1 and backcrosses with both parental species. In addition, the C. caretta × E. imbricata hybridization seems to be gender and species biased, and we also found one individual with evidence of multispecies hybridization among C. caretta × E. imbricata × Chelonia mydas. The overall results also indicate that hybridization in this area is a recent phenomenon, spanning at least two generations or ~40 years. © 2012 Blackwell Publishing Ltd.

Respiration in neonate sea turtles.

PubMed

Price, Edwin R; Paladino, Frank V; Strohl, Kingman P; Santidrián T, Pilar; Klann, Kenneth; Spotila, James R

2007-03-01

The pattern and control of respiration is virtually unknown in hatchling sea turtles. Using incubator-raised turtles, we measured oxygen consumption, frequency, tidal volume, and minute volume for leatherback (Dermochelys coriacea) and olive ridley (Lepidochelys olivacea) turtle hatchlings for the first six days after pipping. In addition, we tested the hatchlings' response to hypercapnic, hyperoxic, and hypoxic challenges over this time period. Hatchling sea turtles generally showed resting ventilation characteristics that are similar to those of adults: a single breath followed by a long respiratory pause, slow frequency, and high metabolic rate. With hypercapnic challenge, both species responded primarily by elevating respiratory frequency via a decrease in the non-ventilatory period. Leatherback resting tidal volume increased with age but otherwise, neither species' resting respiratory pattern nor response to gas challenge changed significantly over the first few days after hatching. At the time of nest emergence, sea turtles have achieved a respiratory pattern that is similar to that of actively diving adults.

Fidelity and over-wintering of sea turtles

PubMed Central

Broderick, Annette C; Coyne, Michael S; Fuller, Wayne J; Glen, Fiona; Godley, Brendan J

2007-01-01

While fidelity to breeding sites is well demonstrated in marine turtles, emerging knowledge of migratory routes and key foraging sites is of limited conservation value unless levels of fidelity can be established. We tracked green (Chelonia mydas, n=10) and loggerhead (Caretta caretta, n=10) turtles during their post-nesting migration from the island of Cyprus to their foraging grounds. After intervals of 2–5 years, five of these females were recaptured at the nesting beach and tracked for a second migration. All five used highly similar migratory routes to return to the same foraging and over-wintering areas. None of the females visited other foraging habitats over the study period (units lasted on average 305 days; maximum, 1356 days), moving only to deeper waters during the winter months where they demonstrated extremely long resting dives of up to 10.2 h (the longest breath-holding dive recorded for a marine vertebrate). High levels of fidelity and the relatively discrete nature of the home ranges demonstrate that protection of key migratory pathways, foraging and over-wintering sites can serve as an important tool for the future conservation of marine turtles. PMID:17456456

Comparison of organochlorine pesticides and PCB residues among hawksbill (Eretmochelys imbricata) and green (Chelonia mydas) turtles in the Yucatan Peninsula and their maternal transfer.

PubMed

García-Besné, Gabriela; Valdespino, Carolina; Rendón-von Osten, Jaime

2015-02-15

Organochlorine pesticides and PCB (POPs) concentrations were determined in the blood and eggs of green and hawksbill turtles. We compared concentrations between species, analyzed the relationship between turtle size and the POPs concentrations and the relationship between the concentrations in the blood of the nesting turtles and their eggs. We expected higher concentrations in the hawksbill turtle because of its higher trophic level, but concentrations were not higher in all the cases. Significant differences were found in δ-HCH blood concentrations. Lindane, heptachlor epoxide and PCB 101 concentrations were significantly higher in the hawksbill eggs. The relationship between the size of the turtles and the POP concentrations in the eggs of the hawksbills showed a negative correlation. No correlation was found between the size of the female and concentrations in the blood. In eggs, only the hawksbill turtles exhibited negative correlation in the concentration of mirex and PCB 44 and size. Copyright © 2014 Elsevier Ltd. All rights reserved.

Spatial Ecology of Blanding’s Turtles (Emydoidea blandingii) in Southcentral New Hampshire with Implications to Road Mortality

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walston, Leroy J.; Najjar, Stephen J.; LaGory, Kirk E.

Understanding the spatial ecology and habitat requirements of rare turtle species and the factors that threaten their populations is important for the success of long-term conservation programs. We present results on an eight-year field study in which we used radiotelemetry to monitor the activity and habitat use of 23 adult (male, n = 7; female, n = 16) Blanding’s turtles in southcentral New Hampshire. We found that females occupied home ranges (as defined by minimum convex polygons) that were approximately two times larger than the home ranges of males. Despite the sex difference in home range size, we found nomore » sex difference in core area size (defined as the 50% kernel density estimate). We found that activity patterns varied by season, with increased activity each month after hibernation, and peak activity coinciding with the late spring-early summer nesting season. We observed sex-based and seasonal differences in wetland use. Males appeared to prefer emergent and scrub-shrub wetlands in each season, whereas females preferred scrub-shrub wetlands in spring and ponds in summer and fall. We identified road mortality risk as a potentially important threat for this population because females crossed roads ten times more frequently than males (based on proportion of observations). The preservation of wetland networks, as well as the implementation of measures to minimize road mortality, are important considerations for the long-term persistence of this population.« less

Geographic Patterns of Genetic Variation in a Broadly Distributed Marine Vertebrate: New Insights into Loggerhead Turtle Stock Structure from Expanded Mitochondrial DNA Sequences

PubMed Central

Shamblin, Brian M.; Bolten, Alan B.; Abreu-Grobois, F. Alberto; Bjorndal, Karen A.; Cardona, Luis; Carreras, Carlos; Clusa, Marcel; Monzón-Argüello, Catalina; Nairn, Campbell J.; Nielsen, Janne T.; Nel, Ronel; Soares, Luciano S.; Stewart, Kelly R.; Vilaça, Sibelle T.; Türkozan, Oguz; Yilmaz, Can; Dutton, Peter H.

2014-01-01

Previous genetic studies have demonstrated that natal homing shapes the stock structure of marine turtle nesting populations. However, widespread sharing of common haplotypes based on short segments of the mitochondrial control region often limits resolution of the demographic connectivity of populations. Recent studies employing longer control region sequences to resolve haplotype sharing have focused on regional assessments of genetic structure and phylogeography. Here we synthesize available control region sequences for loggerhead turtles from the Mediterranean Sea, Atlantic, and western Indian Ocean basins. These data represent six of the nine globally significant regional management units (RMUs) for the species and include novel sequence data from Brazil, Cape Verde, South Africa and Oman. Genetic tests of differentiation among 42 rookeries represented by short sequences (380 bp haplotypes from 3,486 samples) and 40 rookeries represented by long sequences (∼800 bp haplotypes from 3,434 samples) supported the distinction of the six RMUs analyzed as well as recognition of at least 18 demographically independent management units (MUs) with respect to female natal homing. A total of 59 haplotypes were resolved. These haplotypes belonged to two highly divergent global lineages, with haplogroup I represented primarily by CC-A1, CC-A4, and CC-A11 variants and haplogroup II represented by CC-A2 and derived variants. Geographic distribution patterns of haplogroup II haplotypes and the nested position of CC-A11.6 from Oman among the Atlantic haplotypes invoke recent colonization of the Indian Ocean from the Atlantic for both global lineages. The haplotypes we confirmed for western Indian Ocean RMUs allow reinterpretation of previous mixed stock analysis and further suggest that contemporary migratory connectivity between the Indian and Atlantic Oceans occurs on a broader scale than previously hypothesized. This study represents a valuable model for conducting comprehensive international cooperative data management and research in marine ecology. PMID:24465810

An assessment of initial body size in loggerhead sea turtle (Caretta caretta) hatchlings in Turkey.

PubMed

Ozdemir, Adem; Ilgaz, Cetin; Kumlutaş, Yusuf; Durmuş, Salih Hakan; Kaska, Yakup; Türkozan, Oğuz

2007-04-01

Eggs, hatchlings, and adult loggerhead turtles, and incubation durations of clutches, were measured on three Turkish beaches (Dalyan, Fethiye and Göksu Delta), and some physical features of nests were compared. These features were not statistically different among the beaches, except for nest depth and distance to the high water mark. There was a positive relationship between hatchling mass and egg size. The carapace length of hatchlings was correlated with both egg diameter and incubation duration. The duration of asynchronous emergence of hatchlings on Fethiye beach was slightly longer than on the other two beaches, and the size of hatchlings decreased as asynchronous emergence proceeded. Of the hatchlings that emerged first, those that died were significantly smaller in SCL and mass than those that lived. These results suggest that smaller hatchlings may not be vigorous enough to emerge earlier from nests, and that they may be less fit.

Measuring behavioral responses of sea turtles, saltwater crocodiles, and crested terns to drone disturbance to define ethical operating thresholds

PubMed Central

Whiting, Scott; Tucker, Tony; Guinea, Michael; Raith, Andrew; Douglas, Ryan

2018-01-01

Drones are being increasingly used in innovative ways to enhance environmental research and conservation. Despite their widespread use for wildlife studies, there are few scientifically justified guidelines that provide minimum distances at which wildlife can be approached to minimize visual and auditory disturbance. These distances are essential to ensure that behavioral and survey data have no observer bias and form the basis of requirements for animal ethics and scientific permit approvals. In the present study, we documented the behaviors of three species of sea turtle (green turtles, Chelonia mydas, flatback turtles, Natator depressus, hawksbill turtles, Eretmochelys imbricata), saltwater crocodiles (Crocodylus porosus), and crested terns (Thalasseus bergii) in response to a small commercially available (1.4 kg) multirotor drone flown in Northern Territory and Western Australia. Sea turtles in nearshore waters off nesting beaches or in foraging habitats exhibited no evasive behaviors (e.g. rapid diving) in response to the drone at or above 20–30 m altitude, and at or above 10 m altitude for juvenile green and hawksbill turtles foraging on shallow, algae-covered reefs. Adult female flatback sea turtles were not deterred by drones flying forward or stationary at 10 m altitude when crawling up the beach to nest or digging a body pit or egg chamber. In contrast, flyovers elicited a range of behaviors from crocodiles, including minor, lateral head movements, fleeing, or complete submergence when a drone was present below 50 m altitude. Similarly, a colony of crested terns resting on a sand-bank displayed disturbance behaviors (e.g. flight response) when a drone was flown below 60 m altitude. The current study demonstrates a variety of behavioral disturbance thresholds for diverse species and should be considered when establishing operating conditions for drones in behavioral and conservation studies. PMID:29561901

Current transport of leatherback sea turtles (Dermochelys coriacea) in the ocean.

PubMed

Luschi, P; Sale, A; Mencacci, R; Hughes, G R; Lutjeharms, J R E; Papi, F

2003-11-07

While the long-distance movements of pelagic vertebrates are becoming known thanks to satellite telemetry, the factors determining their courses have hardly been investigated. We have analysed the effects of oceanographic factors on the post-nesting movements of three satellite-tracked leatherback turtles (Dermochelys coriacea) moving in the southwest Indian Ocean. By superimposing the turtle tracks on contemporaneous images of sea-surface temperatures and sea height anomalies, we show that currentrelated features dominate the shape of the reconstructed routes. After an initial offshore movement, turtles moved along straight routes when in the core of the current, or executed loops within eddies. Large parts of the routes were strikingly similar to those of surface drifters tracked in the same region. These findings document that long-lasting oceanic movements of marine turtles may be shaped by oceanic currents.

Current transport of leatherback sea turtles (Dermochelys coriacea) in the ocean.

PubMed Central

Luschi, P; Sale, A; Mencacci, R; Hughes, G R; Lutjeharms, J R E; Papi, F

2003-01-01

While the long-distance movements of pelagic vertebrates are becoming known thanks to satellite telemetry, the factors determining their courses have hardly been investigated. We have analysed the effects of oceanographic factors on the post-nesting movements of three satellite-tracked leatherback turtles (Dermochelys coriacea) moving in the southwest Indian Ocean. By superimposing the turtle tracks on contemporaneous images of sea-surface temperatures and sea height anomalies, we show that currentrelated features dominate the shape of the reconstructed routes. After an initial offshore movement, turtles moved along straight routes when in the core of the current, or executed loops within eddies. Large parts of the routes were strikingly similar to those of surface drifters tracked in the same region. These findings document that long-lasting oceanic movements of marine turtles may be shaped by oceanic currents. PMID:14667360

Study of the effects of oil on marine turtles. Volume 2. Technical report. Final report, 30 September 1983-1 October 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vargo, S.; Lutz, P.; Odell, D.

1986-09-15

The objective of the study was to determine the effects of oil on marine turtles. An experimental program was carried out on 3-20 month old loggerhead and 3-16 month old green turtles to determine behavioral and physiological effects of oil using South Louisiana Crude Oil (SLCO) preweathered for 48 hrs. The behavioral experiments indicated that both species of marine turtles had a limited ability to avoid oil slicks, but experiments to determine avoidance/attraction to floating tar balls were inconclusive. The physiological experiments showed that the respiration, skin, some aspects of blood chemistry and composition, and salt gland function of 15-18more » month old loggerhead sea turtles were significantly affected. Spills in the vicinity of nesting beaches are of special concern.« less

Climate change increases the production of female hatchlings at a northern sea turtle rookery.

PubMed

Reneker, J L; Kamel, S J

2016-12-01

The most recent climate change projections show a global increase in temperatures, along with major adjustments to precipitation, throughout the 21st century. Species exhibiting temperature-dependent sex determination are highly susceptible to such changes since the incubation environment influences critical offspring characteristics such as survival and sex ratio. Here we show that the mean incubation duration of loggerhead sea turtle (Caretta caretta) nests from a high-density nesting beach on Bald Head Island, North Carolina, USA has decreased significantly over the past 25 yr. This decrease in incubation duration is significantly positively correlated with mean air temperature and negatively correlated with mean precipitation during the nesting season. Additionally, although no change in hatching success was detected during this same period, a potentially detrimental consequence of shorter incubation durations is that they lead to the production of primarily female offspring. Given that global temperatures are predicted to increase by as much as 4°C over the next century, the mass feminization of sea turtle hatchlings is a high-priority concern. While presently limited in number, studies using long-term data sets to examine the temporal correlation between offspring characteristics and climatic trends are essential for understanding the scope and direction of climate change effects on species persistence. © 2016 by the Ecological Society of America.

Artificial nesting habitats as a conservation strategy for turtle populations experiencing global change.

PubMed

Wnek, John P; Bien, Walter F; Avery, Harold W

2013-06-01

Diamondback terrapins (Malaclemys terrapin) inhabit estuaries in eastern USA and may tolerate salinity of sea-water for short durations. Many North American estuaries are adversely affected by anthropogenic impacts, such as pollution, dredging and invasion by non-native plants. Many nesting areas have been altered or destroyed, causing terrapins to nest on roadsides and artificial islands made of dredged substrate from bottom sediments. Shading by non-native plants may suppress development and reduce survival of embryos. In Barnegat Bay, New Jersey, USA, there is a mosaic of natural and degraded terrapin nesting habitats. We investigated the effects of dredge soil and shade on the hatching success of diamondback terrapins to determine whether nesting habitat could be increased by using dredged bottom sediments. In year 1, unshaded nests in natural loamy-sand had the highest hatching success (55.2%), while nests in dredge soil produced no hatchlings. In year 2, nests in unshaded loamy-sand had a hatching success of 85.3%, whereas those in dredge soil, aged 1 year, had a hatching success of 59.4%. Dredge soil improved as an incubation substrate after aging 1 year by the washout of salt. Nest temperatures were generally cool and produced mostly male hatchlings. Uncontaminated dredge soil may provide suitable nesting substrates for diamondback terrapins if used after one year, and may be particularly beneficial if used for constructing islands that provide new nesting sites with reduced access of mammalian predators. © 2013 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

Spatial and temporal use of floodplain habitats by lentic and lotic species of aquatic turtles.

PubMed

Bodie, J R; Semlitsch, R D

2000-01-01

We investigated the use of aquatic and terrestrial floodplain habitats by lentic and lotic turtles inhabiting the Missouri River, a contemporary, regulated large river. Specifically, we tested whether habitats were used differentially by turtle species, sexes, and life stages over biologically determined spatial and temporal scales. We monitored female and male false map turtles (Graptemys pseudogeographica) and slider turtles (Trachemys scripta) for 14 months, using radiotelemetry. In addition, over a 3-year period we trapped G. pseudogeographica (n=591) and T. scripta (n=129) to supplement data on habitat use. Movements based on radiotelemetry and recaptures were summarized for each individual. Both species of turtles displayed dynamic annual activity patterns and used diverse habitats including those typically considered terrestrial. Although G. pseudogeographica and T. scripta spent a substantial portion of the year in the Missouri River (primarily in the cool months), newly created scour habitats also appeared to attract turtles during the cool season. However, in the warm months, habitat use became much more diverse, with turtles occupying all identified habitats including flooded agriculture and forest. Relative to their proportions, slough and scour habitats appeared to be highly favored while forests older than 4 years and agricultural habitats were proportionally less favored. We found few differences between species. However, males of both species were consistently more sedentary, used half as many habitats, and moved half as far from the river as did females, especially during May through July. Juveniles of both species were captured on average farther from the river than were adults, perhaps reflecting the close proximity of both nesting areas and shallow, productive habitats free of aquatic predators. We estimate a riparian zone of 449 m that encompasses 95% of the population movements away from the river and discuss the quality of habitats important to reproduction and survival of lentic and lotic floodplain turtles. These spatial and temporal movement patterns, in light of their potential adaptive costs and benefits to G. pseudogeographica and T. scripta, are critical to understanding the ecology of long-lived vertebrates that depend on contemporary large rivers.

Breeding periodicity for male sea turtles, operational sex ratios, and implications in the face of climate change.

PubMed

Hays, Graeme C; Fossette, Sabrina; Katselidis, Kostas A; Schofield, Gail; Gravenor, Mike B

2010-12-01

Species that have temperature-dependent sex determination (TSD) often produce highly skewed offspring sex ratios contrary to long-standing theoretical predictions. This ecological enigma has provoked concern that climate change may induce the production of single-sex generations and hence lead to population extirpation. All species of sea turtles exhibit TSD, many are already endangered, and most already produce sex ratios skewed to the sex produced at warmer temperatures (females). We tracked male loggerhead turtles (Caretta caretta) from Zakynthos, Greece, throughout the entire interval between successive breeding seasons and identified individuals on their breeding grounds, using photoidentification, to determine breeding periodicity and operational sex ratios. Males returned to breed at least twice as frequently as females. We estimated that the hatchling sex ratio of 70:30 female to male for this rookery will translate into an overall operational sex ratio (OSR) (i.e., ratio of total number of males vs females breeding each year) of close to 50:50 female to male. We followed three male turtles for between 10 and 12 months during which time they all traveled back to the breeding grounds. Flipper tagging revealed the proportion of females returning to nest after intervals of 1, 2, 3, and 4 years were 0.21, 0.38, 0.29, and 0.12, respectively (mean interval 2.3 years). A further nine male turtles were tracked for short periods to determine their departure date from the breeding grounds. These departure dates were combined with a photoidentification data set of 165 individuals identified on in-water transect surveys at the start of the breeding season to develop a statistical model of the population dynamics. This model produced a maximum likelihood estimate that males visit the breeding site 2.6 times more often than females (95%CI 2.1, 3.1), which was consistent with the data from satellite tracking and flipper tagging. Increased frequency of male breeding will help ameliorate female-biased hatchling sex ratios. Combined with the ability of males to fertilize the eggs of many females and for females to store sperm to fertilize many clutches, our results imply that effects of climate change on the viability of sea turtle populations are likely to be less acute than previously suspected. © 2010 Society for Conservation Biology.

Proceedings of the 2015 international summit on fibropapillomatosis: Global status, trends, and population impacts

USGS Publications Warehouse

Hargrove, Stacy A.; Work, Thierry M.; Brunson, Shandell; Foley, Allen M.; Balazs, George H.

2016-01-01

The 2015 International Summit on Fibropapillomatosis (FP) was convened in Honolulu, Hawaii June 11-14, 2015. Scientists from around the world were invited to present results from sea turtle monitoring and research programs as they relate to the global status, trends, and population impacts of FP on green turtles. The participants engaged in discussions that resulted in the following conclusions: 1.Globally, FP has long been present in wild sea turtle populations the earliest mention was in the late 1800s in the Florida Keys. 2.FP primarily affects medium-sized immature turtles in coastal foraging pastures. 3.Expression of FP differs across ocean basins and to some degree within basins. Turtles in the Southeast US, Caribbean, Brazil, and Australia rarely have oral tumors (inside the mouth cavity), whereas they are common and often severe in Hawaii. Internal tumors (on vital organs) occur in the Atlantic and Hawaii, but only rarely in Australia. Liver tumors are common in Florida but not in Hawaii. 4.Recovery from FP through natural processes, when the affliction is not severe, has been documented in wild populations globally. 5.FP causes reduced survivorship, but documented mortality rates in Australia and Hawaii are low. The mortality impact of FP is not currently exceeding population growth rates in some intensively monitored populations (e.g., Florida, Hawaii) as evidenced by increasing nesting trends despite the incidence of FP in immature foraging populations. 6.Pathogens, hosts, and potential disease and environmental cofactors have the capacity to change; while we are having success now, there needs to be continued monitoring to detect changes in the distribution, occurrence, and severity of the disease. 7.While we do not have clear evidence to provide the direct link, globally, the preponderance of sites with a high frequency of FP tumors are areas with some degree of degradation resulting from altered watersheds. Watershed management and responsible coastal development may be the best approach for reducing the spread and prevalence of the disease. 8.Future research efforts should employ a multi-factorial ecological approach (e.g., virology, parasitology, genetics, health, diet, habitat use, water quality, etc.) since there are likely several environmental cofactors involved in the expression of the disease, which is still thought to be caused by a herpesvirus. 9.Minimum FP data collection in new areas should include: individual identification (photo ID, PIT tags, etc.), standard measurements (length and weight), presence/absence of tumors, tumor severity, body condition, oral examination, method of capture, and effort

The rate of predation by fishes on hatchlings of the green turtle ( Chelonia mydas)

NASA Astrophysics Data System (ADS)

Gyuris, E.

1994-07-01

This study addresses the need for empirical data on the survival of sea turtle hatchlings after entry into the sea by (1) developing a method for measuring marine predation; (2) estimating predation rates while crossing the reef; and (3) investigating the effect of environmental variables on predation rates. Predation rates were quantified by following individual hatchlings, tethered by a 10m monofilament nylon line, as they swam from the water's edge towards the reef crest. Predation rates under particular combinations of environmental variables (tide, time of day, and moon phase) were measured in separate trials. Predation rates varied among trials from 0 to 85% with a mean of 31% (SE=2.5%). The simplest logistic regression model that explained variation in predation contained tide and moon phase as predictor variables. The results suggest that noctural emergence from the nest is a behavioral adaptation to minimize exposure to the heat of the day rather than a predator-escape mechanism. For the green turtle populations breeding in eastern Australia, most first year mortality is caused by predation while crossing the reef within the first hour of entering the sea.

Past primary sex-ratio estimates of 4 populations of Loggerhead sea turtle based on TSP durations.

NASA Astrophysics Data System (ADS)

Monsinjon, Jonathan; Kaska, Yakup; Tucker, Tony; LeBlanc, Anne Marie; Williams, Kristina; Rostal, David; Girondot, Marc

2016-04-01

Ectothermic species are supposed to be strongly affected by climate change and particularly those that exhibit temperature-dependent sex-determination (TSD). Actually, predicting the embryonic response of such organism to incubation-temperature variations in natural conditions remains challenging. In order to assess the vulnerability of sea turtles, primary sex-ratio estimates should be produced at pertinent ecological time and spatial scales. Although information on this important demographic parameter is one of the priorities for conservation purpose, accurate methodology to produce such an estimate is still lacking. The most commonly used method invocates incubation duration as a proxy for sex-ratio. This method is inappropriate because temperature influences incubation duration during all development whereas sex is influenced by temperature during only part of development. The thermosensitive period of development for sex determination (TSP) lies in the middle third of development. A model of embryonic growth must be used to define precisely the position of the TSP at non-constant incubation temperatures. The thermal reaction norm for embryonic growth rate have been estimated for 4 distinct populations of the globally distributed and threatened marine turtle Caretta caretta. A thermal reaction norm describes the pattern of phenotypic expression of a single genotype across a range of temperatures. Moreover, incubation temperatures have been reconstructed for the last 35 years using a multi-correlative model with climate temperature. After development of embryos have been modelled, we estimated the primary sex-ratio based on the duration of the TSP. Our results suggests that Loggerhead sea turtles nesting phenology is linked with the period within which both sexes can be produced in variable proportions. Several hypotheses will be discussed to explain why Caretta caretta could be more resilient to climate change than generally thought for sex determination.

Juvenile recruitment in loggerhead sea turtles linked to decadal changes in ocean circulation.

PubMed

Ascani, François; Van Houtan, Kyle S; Di Lorenzo, Emanuele; Polovina, Jeffrey J; Jones, T Todd

2016-11-01

Given the threats of climate change, understanding the relationship of climate with long-term population dynamics is critical for wildlife conservation. Previous studies have linked decadal climate oscillations to indices of juvenile recruitment in loggerhead sea turtles (Caretta caretta), but without a clear understanding of mechanisms. Here, we explore the underlying processes that may explain these relationships. Using the eddy-resolving Ocean General Circulation Model for the Earth Simulator, we generate hatch-year trajectories for loggerhead turtles emanating from Japan over six decades (1950-2010). We find that the proximity of the high-velocity Kuroshio Current to the primary nesting areas in southern Japan is remarkably stable and that hatchling dispersal to oceanic habitats itself does not vary on decadal timescales. However, we observe a shift in latitudes of trajectories, consistent with the Pacific Decadal Oscillation (PDO). In a negative PDO phase, the Kuroshio Extension Current (KEC) is strong and acts as a physical barrier to the northward transport of neonates. As a result, hatch-year trajectories remain mostly below 35°N in the warm, unproductive region south of the Transition Zone Chlorophyll Front (TZCF). During a positive PDO phase, however, the KEC weakens facilitating the neonates to swim north of the TZCF into cooler and more productive waters. As a result, annual cohorts from negative PDO years may face a lack of resources, whereas cohorts from positive PDO years may find sufficient resources during their pivotal first year. These model outputs indicate that the ocean circulation dynamics, combined with navigational swimming behavior, may be a key factor in the observed decadal variability of sea turtle populations. © 2016 John Wiley & Sons Ltd.

Marine turtles use geomagnetic cues during open-sea homing.

PubMed

Luschi, Paolo; Benhamou, Simon; Girard, Charlotte; Ciccione, Stephane; Roos, David; Sudre, Joël; Benvenuti, Silvano

2007-01-23

Marine turtles are renowned long-distance navigators, able to reach remote targets in the oceanic environment; yet the sensory cues and navigational mechanisms they employ remain unclear [1, 3]. Recent arena experiments indicated an involvement of magnetic cues in juvenile turtles' homing ability after simulated displacements [4, 5], but the actual role of geomagnetic information in guiding turtles navigating in their natural environment has remained beyond the reach of experimental investigations. In the present experiment, twenty satellite-tracked green turtles (Chelonia mydas) were transported to four open-sea release sites 100-120 km from their nesting beach on Mayotte island in the Mozambique Channel; 13 of them had magnets attached to their head either during the outward journey or during the homing trip. All but one turtle safely returned to Mayotte to complete their egg-laying cycle, albeit with indirect routes, and showed a general inability to take into account the deflecting action of ocean currents as estimated through remote-sensing oceanographic measurements [7]. Magnetically treated turtles displayed a significant lengthening of their homing paths with respect to controls, either when treated during transportation or when treated during homing. These findings represent the first field evidence for the involvement of geomagnetic cues in sea-turtle navigation.

Estimating freshwater turtle mortality rates and population declines following hook ingestion.

PubMed

Steen, David A; Robinson, Orin J

2017-12-01

Freshwater turtle populations are susceptible to declines following small increases in the mortality of adults, making it essential to identify and understand potential threats. Freshwater turtles ingest fish hooks associated with recreational angling, and this is likely a problem because hook ingestion is a source of additive mortality for sea turtles. We used a Bayesian-modeling framework, observed rates of hook ingestion by freshwater turtles, and mortality of sea turtles from hook ingestion to examine the probability that a freshwater turtle in a given population ingests a hook and subsequently dies from it. We used the results of these analyses and previously published life-history data to simulate the effects of hook ingestion on population growth for 3 species of freshwater turtle. In our simulation, the probability that an individual turtle ingests a hook and dies as a result was 1.2-11%. Our simulation results suggest that this rate of mortality from hook ingestion is sufficient to cause population declines. We believe we have identified fish-hook ingestion as a serious yet generally overlooked threat to the viability of freshwater turtle populations. © 2017 Society for Conservation Biology.

Metabolic circadian rhythms in embryonic turtles.

PubMed

Loudon, Fiona Kay; Spencer, Ricky-John; Strassmeyer, Alana; Harland, Karen

2013-07-01

Oviparous species are model organisms for investigating embryonic development of endogenous physiological circadian rhythms without the influence of maternal biorhythms. Recent studies have demonstrated that heart rates and metabolic rates of embryonic turtles are not constant or always maximal and can be altered in response to the presence of embryos at a more advanced stage of development within the nest. A first step in understanding the physiological mechanisms underpinning these responses in embryonic ectothermic organisms is to develop metabolic profiles (e.g., heart rate) at different temperatures throughout incubation. Heart beat and rhythmic patterns or changes in development may represent important signals or cues within a nest and may be vital to coordinate synchronous hatching well in advance of the final stages of incubation. We developed baseline embryonic heart-rate profiles of embryos of the short-necked Murray River turtle (Emydura macquarii) to determine the stage of embryogenesis that metabolic circadian rhythms become established, if at all. Eggs were incubated at constant temperatures (26°C and 30°C) and heart rates were monitored at 6-h intervals over 24 h every 7-11 days until hatching. Circadian heart rate rhythms were detected at the mid-gestation period and were maintained until hatching. Heart rates throughout the day varied by up to 20% over 24 h and were not related to time of day. This study demonstrated that endogenous metabolic circadian rhythms in developing embryos in turtle eggs establish earlier in embryogenesis than those documented in other vertebrate taxa during embryogenesis. Early establishment of circadian rhythms in heart rates may be critical for communication among embryos and synchrony in hatching and emergence from the nest.

Waste characterization study for the Kemp's Ridley sea turtle. Technical memo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malone, R.F.; Guarisco, M.

1988-02-01

The Kemp's Ridley sea turtle, Lepidochelys kempi, is an endangered species. The National Marine Fisheries Service's Head Start program is part of an international operation to save the turtles from extinction. Under the Head Start program, eggs from the Ridley's only known wild nesting beach at Rancho Nuevo in Mexico are transported to Padre Island on the Texas coast to be hatched. The head start enables the turtles to develop a survival advantage. The principal objective was to develop baseline waste-characterization data required to design a waste-water treatment scheme for the Galveston Head Start facility. As a secondary objective, preliminarymore » testing of some filtration components was undertaken to determine which units were most appropriate for inclusion in a wastewater treatment scheme.« less

Demographic and genetic status of an isolated population of bog turtles (Glyptemys muhlenbergii): Implications for managing small populations of long-lived animals

USGS Publications Warehouse

Pittman, Shannon E.; King, T.L.; Faurby, S.; Dorcas, M.E.

2011-01-01

In this study, we sought to determine the population stability and genetic diversity of one isolated population of the federally-threatened bog turtle (Glyptemys muhlenbergii) in North Carolina. Using capture-recapture data, we estimated adult survival and population growth rate from 1992 to 2007. We found that the population decreased from an estimated 36 adult turtles in 1994 to approximately 11 adult turtles in 2007. We found a constant adult survival of 0. 893 (SE = 0. 018, 95% confidence interval, 0. 853-0. 924) between 1992 and 2007. Using 18 microsatellite markers, we compared the genetic status of this population with five other bog turtle populations. The target population displayed allelic richness (4. 8 ?? 0. 5) and observed heterozygosity (0. 619 ?? 0. 064) within the range of the other bog turtle populations. Coalescent analysis of population growth rate, effective population size, and timing of population structuring event also indicated the genetics of the target population were comparable to the other populations studied. Estimates of effective population size were a proportion of the census size in all populations except the target population, in which the effective population size was larger than the census size (30 turtles vs. 11 turtles). We attribute the high genetic diversity in the target population to the presence of multiple generations of old turtles. This study illustrates that the demographic status of populations of long-lived species may not be reflected genetically if a decline occurred recently. Consequently, the genetic integrity of populations of long-lived animals experiencing rapid demographic bottlenecks may be preserved through conservation efforts effective in addressing demographic problems. ?? 2011 Springer Science+Business Media B.V.

Conceptual Model Development for Sea Turtle Nesting Habitat: Support for USACE Navigation Projects

DTIC Science & Technology

2015-08-01

regional values. • Beach Width: The width of the beach (m) defines the region from the shoreline to the dune toe . Loggerhead turtles tend to prefer...primary drivers of the model parameters. • Beach Elevation: Beach elevation (m) is measured from the shoreline to the dune toe . Elevation influences...mapping, and morphological features in combination with imagery-derived environmental parameters (i.e., dune vegetation) have not been attempted

Fusarium solani is responsible for mass mortalities in nests of loggerhead sea turtle, Caretta caretta, in Boavista, Cape Verde.

PubMed

Sarmiento-Ramírez, Jullie M; Abella, Elena; Martín, María P; Tellería, María T; López-Jurado, Luis F; Marco, Adolfo; Diéguez-Uribeondo, Javier

2010-11-01

The fungus Fusarium solani (Mart.) Saccardo (1881) was found to be the cause of infections in the eggs of the sea turtle species Caretta caretta in Boavista Island, Cape Verde. Egg shells with early and severe symptoms of infection, as well as diseased embryos were sampled from infected nests. Twenty-five isolates with similar morphological characteristics were obtained. Their ITS rRNA gene sequences were similar to the GenBank sequences corresponding to F. solani and their maximum identity ranged from 95% to 100%. Phylogenetic parsimony and Bayesian analyses of these isolates showed that they belong to a single F. solani clade and that they are distributed in two subclades named A and C (the latter containing 23 out of 25). A representative isolate of subclade C was used in challenge inoculation experiments to test Koch postulates. Mortality rates were c. 83.3% in challenged eggs and 8.3% in the control. Inoculated challenged eggs exhibited the same symptoms as infected eggs found in the field. Thus, this work demonstrates that a group of strains of F. solani are responsible for the symptoms observed on turtle-nesting beaches, and that they represent a risk for the survival of this endangered species. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Determination and maternal transfer of heavy metals (Cd, Cu, Zn, Pb and Hg) in the Hawksbill sea turtle (Eretmochelys imbricata) from a nesting colony of Qeshm Island, Iran.

PubMed

Ehsanpour, Maryam; Afkhami, Majid; Khoshnood, Reza; Reich, Kimberly J

2014-06-01

This study was conducted to determine trace metal concentrations (Cd, Cu, Zn, Pb and Hg) in blood and three egg fractions from Eretmochelys imbricata nesting on Qeshm Island in Iran. The results showed detectable levels of all analytes in all fractions. Pb and Hg were detectable in the blood and eggs, reflecting a maternal transfer. With the exception of Cu and Pb, analyzed elements in eggs were concentrated in yolk. Only Zn in blood had a significant correlation with the body size and weight (p < 0.01). It appears that Hawksbill sea turtles can regulate Zn concentrations through homeostatic processes to balance metabolic requirements. The relatively low concentrations of metals in blood support the knowledge that E. imbricata feed mainly on the low trophic levels. All essential and non-essential elements were detectable in blood and in eggs of the hawksbill, reflecting a maternal transfer. Consequently, movement patterns, home ranges of foraging grounds, and availability of food could explain variations in trace element concentrations among female turtles.

The relationship between gut contents and supercooling capacity in hatchling painted turtles (Chrysemys picta).

PubMed

Packard, Gary C; Packard, Mary J

2006-05-01

Painted turtles (Chrysemys picta) typically spend their first winter of life in a shallow, subterranean hibernaculum (the natal nest) where they seemingly withstand exposure to ice and cold by resisting freezing and becoming supercooled. However, turtles ingest soil and fragments of eggshell as they are hatching from their eggs, and the ingestate usually contains efficient nucleating agents that cause water to freeze at high subzero temperatures. Consequently, neonatal painted turtles have only a modest ability to undergo supercooling in the period immediately after hatching. We studied the limit for supercooling (SCP) in hatchlings that were acclimating to different thermal regimes and then related SCPs of the turtles to the amount of particulate matter in their gastrointestinal (GI) tract. Turtles that were transferred directly from 26 degrees C (the incubation temperature) to 2 degrees C did not purge soil from their gut, and SCPs for these animals remained near -4 degrees C for the 60 days of the study. Animals that were held at 26 degrees C for the duration of the experiment usually cleared soil from their GI tract within 24 days, but SCPs for these turtles were only slightly lower after 60 days than they were at the outset of the experiment. Hatchlings that were acclimating slowly to 2 degrees C cleared soil from their gut within 24 days and realized a modest reduction in their SCP. However, the limit of supercooling in the slowly acclimating animals continued to decline even after all particulate material had been removed from their GI tract, thereby indicating that factors intrinsic to the nucleating agents themselves also may have been involved in the acclimation of hatchlings to low temperature. The lowest SCPs for turtles that were acclimating slowly to 2 degrees C were similar to SCPs recorded in an earlier study of animals taken from natural nests in late autumn, so the current findings affirm the importance of seasonally declining temperatures in preparing animals in the field to withstand conditions that they will encounter during winter.

Do open-cycle hatcheries relying on tourism conserve sea turtles? Sri Lankan developments and economic-ecological considerations.

PubMed

Tisdell, Clem; Wilson, Clevo

2005-04-01

By combining economic analysis of markets with ecological parameters, this article considers the role that tourism-based sea turtle hatcheries (of an open-cycle type) can play in conserving populations of sea turtles. Background is provided on the nature and development of such hatcheries in Sri Lanka. The modeling facilitates the assessment of the impacts of turtle hatcheries on the conservation of sea turtles and enables the economic and ecological consequences of tourism, based on such hatcheries, to be better appreciated. The results demonstrate that sea turtle hatcheries serving tourists can make a positive contribution to sea turtle conservation, but that their conservation effectiveness depends on the way they are managed. Possible negative effects are also identified. Economic market models are combined with turtle population survival relationships to predict the conservation impact of turtle hatcheries and their consequence for the total economic value obtained from sea turtle populations.

Water-vapor conductance of testudinian and crocodilian eggs (class reptilia).

PubMed

Packard, G C; Taigen, T L; Packard, M J; Shuman, R D

1979-09-01

Flexible-shelled eggs of snapping turtles (Chelydra serpentina) have conductances to water vapor that are 55 times higher than predicted for avian eggs of similar size, whereas rigid-shelled eggs of softshell turtles (Trionyx spiniferus) and American alligators (Alligator mississippiensis) have conductances that are only five times higher than expected for comparable eggs of birds. The differences between empirical and predicted values result from the much higher effective pore areas in reptilian eggshells than in those of birds. The relatively high porosities of these reptilian eggs presumably facilitate the transport of oxygen and carbon dioxide eggshells in later stages of incubation when air trapped inside nest chambers may become hypoxic and hypercapnic, yet seem not to lead to excessive transpiration of water vapor owing to the high humidities in nests where incubation occurs.

The navigational feats of green sea turtles migrating from Ascension Island investigated by satellite telemetry.

PubMed Central

Luschi, P; Hays, G C; Del Seppia, C; Marsh, R; Papi, F

1998-01-01

Previous tagging studies of the movements of green turtles (Chelonia mydas) nesting at Ascension Island have shown that they shuttle between this remote target in the Atlantic Ocean and their feeding grounds on the Brazilian coast, a distance of 2300 km or more. Since a knowledge of sea turtle migration routes might allow inferences on the still unknown navigational mechanisms of marine animals, we tracked the postnesting migration of six green turtle females from Ascension Island to Brazil. Five of them reached the proximity of the easternmost stretch of the Brazilian coast, covering 1777-2342 km in 33-47 days. Their courses were impressively similar for the first 1000 km, with three turtles tracked over different dates following indistinguishable paths for the first 300 km. Only the sixth turtle made some relatively short trips in different directions around Ascension. The tracks show that turtles (i) are able to maintain straight courses over long distances in the open sea; (ii) may perform exploratory movements in different directions; (iii) appropriately correct their course during the journey according to external information; and (iv) initially keep the same direction as the west-south-westerly flowing current, possibly guided by chemical cues. PMID:9881473

Habitat collapse due to overgrazing threatens turtle conservation in marine protected areas.

PubMed

Christianen, Marjolijn J A; Herman, Peter M J; Bouma, Tjeerd J; Lamers, Leon P M; van Katwijk, Marieke M; van der Heide, Tjisse; Mumby, Peter J; Silliman, Brian R; Engelhard, Sarah L; van de Kerk, Madelon; Kiswara, Wawan; van de Koppel, Johan

2014-02-22

Marine protected areas (MPAs) are key tools for combatting the global overexploitation of endangered species. The prevailing paradigm is that MPAs are beneficial in helping to restore ecosystems to more 'natural' conditions. However, MPAs may have unintended negative effects when increasing densities of protected species exert destructive effects on their habitat. Here, we report on severe seagrass degradation in a decade-old MPA where hyper-abundant green turtles adopted a previously undescribed below-ground foraging strategy. By digging for and consuming rhizomes and roots, turtles create abundant bare gaps, thereby enhancing erosion and reducing seagrass regrowth. A fully parametrized model reveals that the ecosystem is approaching a tipping point, where consumption overwhelms regrowth, which could potentially lead to complete collapse of the seagrass habitat. Seagrass recovery will not ensue unless turtle density is reduced to nearly zero, eliminating the MPA's value as a turtle reserve. Our results reveal an unrecognized, yet imminent threat to MPAs, as sea turtle densities are increasing at major nesting sites and the decline of seagrass habitat forces turtles to concentrate on the remaining meadows inside reserves. This emphasizes the need for policy and management approaches that consider the interactions of protected species with their habitat.

Habitat collapse due to overgrazing threatens turtle conservation in marine protected areas

PubMed Central

Christianen, Marjolijn J. A.; Herman, Peter M. J.; Bouma, Tjeerd J.; Lamers, Leon P. M.; van Katwijk, Marieke M.; van der Heide, Tjisse; Mumby, Peter J.; Silliman, Brian R.; Engelhard, Sarah L.; van de Kerk, Madelon; Kiswara, Wawan; van de Koppel, Johan

2014-01-01

Marine protected areas (MPAs) are key tools for combatting the global overexploitation of endangered species. The prevailing paradigm is that MPAs are beneficial in helping to restore ecosystems to more ‘natural’ conditions. However, MPAs may have unintended negative effects when increasing densities of protected species exert destructive effects on their habitat. Here, we report on severe seagrass degradation in a decade-old MPA where hyper-abundant green turtles adopted a previously undescribed below-ground foraging strategy. By digging for and consuming rhizomes and roots, turtles create abundant bare gaps, thereby enhancing erosion and reducing seagrass regrowth. A fully parametrized model reveals that the ecosystem is approaching a tipping point, where consumption overwhelms regrowth, which could potentially lead to complete collapse of the seagrass habitat. Seagrass recovery will not ensue unless turtle density is reduced to nearly zero, eliminating the MPA's value as a turtle reserve. Our results reveal an unrecognized, yet imminent threat to MPAs, as sea turtle densities are increasing at major nesting sites and the decline of seagrass habitat forces turtles to concentrate on the remaining meadows inside reserves. This emphasizes the need for policy and management approaches that consider the interactions of protected species with their habitat. PMID:24403341

Hearing in the Juvenile Green Sea Turtle (Chelonia mydas): A Comparison of Underwater and Aerial Hearing Using Auditory Evoked Potentials

PubMed Central

Piniak, Wendy E. D.; Mann, David A.; Harms, Craig A.; Jones, T. Todd; Eckert, Scott A.

2016-01-01

Sea turtles spend much of their life in aquatic environments, but critical portions of their life cycle, such as nesting and hatching, occur in terrestrial environments, suggesting that it may be important for them to detect sounds in both air and water. In this study we compared underwater and aerial hearing sensitivities in five juvenile green sea turtles (Chelonia mydas) by measuring auditory evoked potential responses to tone pip stimuli. Green sea turtles detected acoustic stimuli in both media, responding to underwater stimuli between 50 and 1600 Hz and aerial stimuli between 50 and 800 Hz, with maximum sensitivity between 200 and 400 Hz underwater and 300 and 400 Hz in air. When underwater and aerial hearing sensitivities were compared in terms of pressure, green sea turtle aerial sound pressure thresholds were lower than underwater thresholds, however they detected a wider range of frequencies underwater. When thresholds were compared in terms of sound intensity, green sea turtle sound intensity level thresholds were 2–39 dB lower underwater particularly at frequencies below 400 Hz. Acoustic stimuli may provide important environmental cues for sea turtles. Further research is needed to determine how sea turtles behaviorally and physiologically respond to sounds in their environment. PMID:27741231

Hearing in the Juvenile Green Sea Turtle (Chelonia mydas): A Comparison of Underwater and Aerial Hearing Using Auditory Evoked Potentials.

PubMed

Piniak, Wendy E D; Mann, David A; Harms, Craig A; Jones, T Todd; Eckert, Scott A

2016-01-01

Sea turtles spend much of their life in aquatic environments, but critical portions of their life cycle, such as nesting and hatching, occur in terrestrial environments, suggesting that it may be important for them to detect sounds in both air and water. In this study we compared underwater and aerial hearing sensitivities in five juvenile green sea turtles (Chelonia mydas) by measuring auditory evoked potential responses to tone pip stimuli. Green sea turtles detected acoustic stimuli in both media, responding to underwater stimuli between 50 and 1600 Hz and aerial stimuli between 50 and 800 Hz, with maximum sensitivity between 200 and 400 Hz underwater and 300 and 400 Hz in air. When underwater and aerial hearing sensitivities were compared in terms of pressure, green sea turtle aerial sound pressure thresholds were lower than underwater thresholds, however they detected a wider range of frequencies underwater. When thresholds were compared in terms of sound intensity, green sea turtle sound intensity level thresholds were 2-39 dB lower underwater particularly at frequencies below 400 Hz. Acoustic stimuli may provide important environmental cues for sea turtles. Further research is needed to determine how sea turtles behaviorally and physiologically respond to sounds in their environment.

Demographic evidence of illegal harvesting of an endangered asian turtle.

PubMed

Sung, Yik-Hei; Karraker, Nancy E; Hau, Billy C H

2013-12-01

Harvesting pressure on Asian freshwater turtles is severe, and dramatic population declines of these turtles are being driven by unsustainable collection for food markets, pet trade, and traditional Chinese medicine. Populations of big-headed turtle (Platysternon megacephalum) have declined substantially across its distribution, particularly in China, because of overcollection. To understand the effects of chronic harvesting pressure on big-headed turtle populations, we examined the effects of illegal harvesting on the demography of populations in Hong Kong, where some populations still exist. We used mark-recapture methods to compare demographic characteristics between sites with harvesting histories and one site in a fully protected area. Sites with a history of illegal turtle harvesting were characterized by the absence of large adults and skewed ratios of juveniles to adults, which may have negative implications for the long-term viability of populations. These sites also had lower densities of adults and smaller adult body sizes than the protected site. Given that populations throughout most of the species' range are heavily harvested and individuals are increasingly difficult to find in mainland China, the illegal collection of turtles from populations in Hong Kong may increase over time. Long-term monitoring of populations is essential to track effects of illegal collection, and increased patrolling is needed to help control illegal harvesting of populations, particularly in national parks. Because few, if any, other completely protected populations remain in the region, our data on an unharvested population of big-headed turtles serve as an important reference for assessing the negative consequences of harvesting on populations of stream turtles. Evidencia Demográfica de la Captura Ilegal de una Tortuga Asiática en Peligro. © 2013 Society for Conservation Biology.

Orientation behaviour of leatherback sea turtles within the North Atlantic subtropical gyre

PubMed Central

Dodge, Kara L.; Galuardi, Benjamin; Lutcavage, Molly E.

2015-01-01

Leatherback sea turtles (Dermochelys coriacea) travel thousands of kilometres between temperate feeding and tropical breeding/over-wintering grounds, with adult turtles able to pinpoint specific nesting beaches after multi-year absences. Their extensive migrations often occur in oceanic habitat where limited known sensory information is available to aid in orientation. Here, we examined the migratory orientation of adult male, adult female and subadult leatherbacks during their open-ocean movements within the North Atlantic subtropical gyre by analysing satellite-derived tracks from fifteen individuals over a 2-year period. To determine the turtles' true headings, we corrected the reconstructed tracks for current drift and found negligible differences between current-corrected and observed tracks within the gyre. Individual leatherback headings were remarkably consistent throughout the subtropical gyre, with turtles significantly oriented to the south-southeast. Adult leatherbacks of both sexes maintained similar mean headings and showed greater orientation precision overall. The consistent headings maintained by adult and subadult leatherbacks within the gyre suggest use of a common compass sense. PMID:25761714

The influence of oceanographic features on the foraging behavior of the olive ridley sea turtle Lepidochelys olivacea along the Guiana coast

NASA Astrophysics Data System (ADS)

Chambault, Philippine; de Thoisy, Benoît; Heerah, Karine; Conchon, Anna; Barrioz, Sébastien; Dos Reis, Virginie; Berzins, Rachel; Kelle, Laurent; Picard, Baptiste; Roquet, Fabien; Le Maho, Yvon; Chevallier, Damien

2016-03-01

The circulation in the Western Equatorial Atlantic is characterized by a highly dynamic mesoscale activity that shapes the Guiana continental shelf. Olive ridley sea turtles (Lepidochelys olivacea) nesting in French Guiana cross this turbulent environment during their post-nesting migration. We studied how oceanographic and biological conditions drove the foraging behavior of 18 adult females, using satellite telemetry, remote sensing data (sea surface temperature, sea surface height, current velocity and euphotic depth), simulations of micronekton biomass (pelagic organisms) and in situ records (water temperature and salinity). The occurrence of foraging events throughout migration was located using Residence Time analysis, while an innovative proxy of the hunting time within a dive was used to identify and quantify foraging events during dives. Olive ridleys migrated northwestwards using the Guiana current and remained on the continental shelf at the edge of eddies formed by the North Brazil retroflection, an area characterized by low turbulence and high micronekton biomass. They performed mainly pelagic dives, hunting for an average 77% of their time. Hunting time within a dive increased with shallower euphotic depth and with lower water temperatures, and mean hunting depth increased with deeper thermocline. This is the first study to quantify foraging activity within dives in olive ridleys, and reveals the crucial role played by the thermocline on the foraging behavior of this carnivorous species. This study also provides novel and detailed data describing how turtles actively use oceanographic structures during post-nesting migration.

Temperature-Dependent Sex Determination under Rapid Anthropogenic Environmental Change: Evolution at a Turtle's Pace?

PubMed

Refsnider, Jeanine M; Janzen, Fredric J

2016-01-01

Organisms become adapted to their environment by evolving through natural selection, a process that generally transpires over many generations. Currently, anthropogenically driven environmental changes are occurring orders of magnitude faster than they did prior to human influence, which could potentially outpace the ability of some organisms to adapt. Here, we focus on traits associated with temperature-dependent sex determination (TSD), a classic polyphenism, in a model turtle species to address the evolutionary potential of species with TSD to respond to rapid climate change. We show, first, that sex-ratio outcomes in species with TSD are sensitive to climatic variation. We then identify the evolutionary potential, in terms of heritability, of TSD and quantify the evolutionary potential of 3 key traits involved in TSD: pivotal temperature, maternal nest-site choice, and nesting phenology. We find that these traits display different patterns of adaptive potential: pivotal temperature exhibits moderate heritable variation, whereas nest-site choice and nesting phenology, with considerable phenotypic plasticity, have only modest evolutionary potential to alter sex ratios. Therefore, the most likely response of species with TSD to anthropogenically induced climate change may be a combination of microevolution in thermal sensitivity of the sex-determining pathway and of plasticity in maternal nesting behavior. © The American Genetic Association. 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Successive changes of hematologic characteristics and plasma chemistry values of juvenile loggerhead turtles (Caretta caretta).

PubMed

Kakizoe, Yuka; Sakaoka, Ken; Kakizoe, Futoshi; Yoshii, Makoto; Nakamura, Hitoshi; Kanou, Yoshihiko; Uchida, Itaru

2007-03-01

Hematologic characteristics and plasma chemistry values of juvenile loggerhead turtles (Caretta caretta) from the ages of 1 mo to 3 yr were obtained to establish baseline values. Five clinically normal loggerhead turtles were selected from the same clutch and raised in an indoor artificial nesting beach. Blood samples were successively collected and examined for various blood characteristics for a maximum total of 15 times. Hematologic characteristics, including packed cell volume, white blood cell counts, and white blood cell differentials; and plasma chemistry values, including total bilirubin, total protein, albumin, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, gamma-glutamic transpeptidase, creatinine, blood urea nitrogen, uric acid, alkaline phosphatase, amylase, triglyceride, total cholesterol, ionized sodium, ionized potassium and ionized chlorine, were measured. These results were used to establish a hematology and blood chemistry baseline for captive juvenile loggerhead turtles and will aid in their medical management.

Modeling the effects of climate change-induced shifts in reproductive phenology on temperature-dependent traits.

PubMed

Telemeco, Rory S; Abbott, Karen C; Janzen, Fredric J

2013-05-01

By altering phenology, organisms have the potential to match life-history events with suitable environmental conditions. Because of this, phenological plasticity has been proposed as a mechanism whereby populations might buffer themselves from climate change. We examine the potential buffering power of advancing one aspect of phenology, nesting date, on sex ratio in painted turtles (Chrysemys picta), a species with temperature-dependent sex determination. We developed a modified constant temperature equivalent model that accounts for the effect of the interaction among climate change, oviposition date, and seasonal thermal pattern on temperature during sexual differentiation and thus on offspring sex ratio. Our results suggest that females will not be able to buffer their progeny from the negative consequences of climate change by adjusting nesting date alone. Not only are offspring sex ratios predicted to become 100% female, but our model suggests that many nests will fail. Because the seasonal thermal trends that we consider are experienced by most temperate species, our result that adjusting spring phenology alone will be insufficient to counter the effects of directional climate change may be broadly applicable.

An Overview of My Internship with the Ecological Program at John F. Kennedy Space Center

NASA Technical Reports Server (NTRS)

Owen, Samantha

2010-01-01

During my internship with Innovative Health Applications, I participated in numerous longterm research projects involving the study of various plant and animal life at the Kennedy Space Center (KSC). I observed the monitoring of nesting sea turtles. I learned about the transfer of egg clutches from the northern Gulf Coast in an effort to help the hatchlings avoid the oil spill in the Gulf of Mexico. I gained knowledge of tracking the movements of important sport fish and sharks in this area using a hydro-acoustic tag and receiver system. This effort included routinely taking water quality data at multiple sites around KSC. Alligator population and nesting assessments was another part of my internship. I observed the biologists take morphometric measurements, blood, urine and tissue samples from alligators found in KSC waterways. I assisted in taking photosynthesis and reflectance measurements on various scrub oaks and palmettos. I participated in Florida Scrub-Jay surveys in an effort to monitor their population trends and was involved in Southeastern beach mouse trapping and identification. I also assisted in seagrass surveys monitoring the health of the seagrass beds.

Global research priorities for sea turtles: Informing management and conservation in the 21st century

USGS Publications Warehouse

Hamann, M.; Godfrey, M.H.; Seminoff, J.A.; Barata, P.C.R.; Bjorndal, K.A.; Bolten, A.B.; Broderick, A.C.; Campbell, L.M.; Carreras, C.; Casale, P.; Chaloupka, M.; Chan, S.-K.; Coyne, M.; Crowder, L.B.; Diez, C.E.; Dutton, P.H.; Epperly, S.P.; FitzSimmons, N.N.; Formia, A.; Girondot, M.; Hays, G.C.; Cheng, I.J.; Kaska, Y.; Lewison, R.; Mortimer, J.A.; Nichols, W.J.; Reina, R.D.; Shanker, K.; Spotila, J.R.; Tomás, J.; Wallace, B.P.; Work, Thierry M.; Zbinden, N.; Godley, B.J.

2010-01-01

Over the past 3 decades, the status of sea turtles and the need for their protection to aid population recovery have increasingly captured the interest of government agencies, non-governmental organisations (NGOs) and the general public worldwide. This interest has been matched by increased research attention, focusing on a wide variety of topics relating to sea turtle biology and ecology, together with the interrelations of sea turtles with the physical and natural environments. Although sea turtles have been better studied than most other marine fauna, management actions and their evaluation are often hindered by the lack of data on turtle biology, human–turtle interactions, turtle population status and threats. In an effort to inform effective sea turtle conservation a list of priority research questions was assembled based on the opinions of 35 sea turtle researchers from 13 nations working in fields related to turtle biology and/or conservation. The combined experience of the contributing researchers spanned the globe as well as many relevant disciplines involved in conservation research. An initial list of more than 200 questions gathered from respondents was condensed into 20 metaquestions and classified under 5 categories: reproductive biology, biogeography, population ecology, threats and conservation strategies.

Environmental Assessment for Beach Shoreline Protection at Patrick Air Force Base, Florida

DTIC Science & Technology

2012-02-27

3) a Florida Panhandle nesting subpopulation, occurring at Eglin Air Force Base and the beaches near Panama City, Florida; (4) a Yucatan nesting...subpopulation, occurring on the Eastern Yucatan Peninsula, Mexico (Marquez 1990 and Turtle Expert Working Group or TEWG 2000); and (5) a Dry Tortugas...the Yucatan Peninsula. Additional important foraging areas in the western Atlantic include the Mosquito Lagoon and Indian River Lagoon systems and

A novel hypothesis for the adaptive maintenance of environmental sex determination in a turtle.

PubMed

Spencer, R-J; Janzen, F J

2014-08-22

Temperature-dependent sex determination (TSD) is widespread in reptiles, yet its adaptive significance and mechanisms for its maintenance remain obscure and controversial. Comparative analyses identify an ancient origin of TSD in turtles, crocodiles and tuatara, suggesting that this trait should be advantageous in order to persist. Based on this assumption, researchers primarily, and with minimal success, have employed a model to examine sex-specific variation in hatchling phenotypes and fitness generated by different incubation conditions. The unwavering focus on different incubation conditions may be misplaced at least in the many turtle species in which hatchlings overwinter in the natal nest. If overwintering temperatures differentially affect fitness of male and female hatchlings, TSD might be maintained adaptively by enabling embryos to develop as the sex best suited to those overwintering conditions. We test this novel hypothesis using the painted turtle (Chrysemys picta), a species with TSD in which eggs hatch in late summer and hatchlings remain within nests until the following spring. We used a split-clutch design to expose field-incubated hatchlings to warm and cool overwintering (autumn-winter-spring) regimes in the laboratory and measured metabolic rates, energy use, body size and mortality of male and female hatchlings. While overall mortality rates were low, males exposed to warmer overwintering regimes had significantly higher metabolic rates and used more residual yolk than females, whereas the reverse occurred in the cool temperature regime. Hatchlings from mixed-sex nests exhibited similar sex-specific trends and, crucially, they were less energy efficient and grew less than same-sex hatchlings that originated from single-sex clutches. Such sex- and incubation-specific physiological adaptation to winter temperatures may enhance fitness and even extend the northern range of many species that overwinter terrestrially. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Decline of the Sea Turtles: Causes and Prevention.

ERIC Educational Resources Information Center

National Academy of Sciences - National Research Council, Washington, DC. Commission on Life Sciences.

A report submitted by the Committee on Sea Turtle Conservation, addresses threats to the world's sea turtle populations to fulfill a mandate of the Endangered Species Act Amendments of 1988. It presents information on the populations, biology, ecology, and behavior of five endangered or threatened turtle species: the Kemp's ridley, loggerhead,…

Unusual population attributes of invasive red-eared slider turtles (Trachemys scripta elegans) in Japan: do they have a performance advantage?

USGS Publications Warehouse

Taniguchi, Mari; Lovich, Jeffrey E.; Mine, Kanako; Ueno, Shintaro; Kamezaki, Naoki

2017-01-01

The slider turtle (Trachemys scripta Thunberg in Schoepff, 1792) is native to the USA and Mexico. Due to the popularity of their colorful hatchlings as pets, they have been exported worldwide and are now present on all continents, except Antarctica. Slider turtles are well-established in Japan and occupy aquatic habitats in urban and agricultural areas, to the detriment of native turtles with which they compete. We asked the overall question, do slider turtles in Japan have a performance advantage because they are liberated from the numerous competing turtle species in their native range and released from many of their natural predators? Traits compared included various measures of adult body size (mean, maximum), female size at maturity as measured by size of gravid females, clutch size, population density and biomass, sex ratio, and sexual size dimorphism, the latter two a partial reflection of growth and maturity differences between the sexes. We sampled slider turtle populations in three habitats in Japan and compared population attributes with published data for the species from throughout its native range in the USA. Mean male body sizes were at the lower end of values from the USA suggesting that males in Japan may mature at smaller body sizes. The smallest gravid females in Japan mature at smaller body sizes but have mean clutch sizes larger than some populations in the USA. Compared to most populations in the USA, slider turtles achieve higher densities and biomasses in Japanese wetlands, especially the lotic system we sampled. Sex ratios were female-biased, the opposite of what is reported for many populations in protected areas of the USA. Sexual size dimorphism was enhanced relative to native populations with females as the larger sex. The enhanced dimorphism is likely a result of earlier size of maturity in Japanese males and the large size of mature (gravid) Japanese females. Slider turtles appear to have a performance advantage over native turtles in Japan, possibly as a result of being released from competition with numerous sympatric turtle species in their native range, and the absence of many co-evolved predators and parasites in Japan. This slight competitive edge, coupled with the catholic diet and broad tolerance of varying aquatic habitats of slider turtles, is reflected in their dominance over native and naturalized Japanese turtles in altered aquatic habitats.

Perceptions of fishers to sea turtle bycatch, illegal capture and consumption in the San Ignacio-Navachiste-Macapule lagoon complex, Gulf of California, Mexico.

PubMed

Aguilar-González, Myrna E; Luna-González, Antonio; Aguirre, Alonso; Zavala-Norzagaray, Alan A; Mundo-Ocampo, Manuel; González-Ocampo, Héctor A

2014-01-01

In this study, 10% of all registered fishermen in the coastal towns of Navachiste in Sinaloa, in northwestern Mexico, answered a survey designed to collect data on their perceptions of the following topics: the impact of turtle meat consumption; human health; bycatch; illegal turtle fishing; the illegal sea turtle market; the local economy; pollution; environmental education; the success of protective legislation; and sea turtle-based ecotourism. Perceptions were analyzed using the fuzzy logic method through classification into 5 fuzzy membership sets: VL, very low; L, low; M, moderate; H, high; VH, very high. The 9 topics generated decision areas upon applying fuzzy inference that revealed the membership level of the answers in each fuzzy set. The economic potential of sea turtle-based ecotourism and the economic profitability of the illegal turtle meat market were perceived as VL. Conservation legislation was perceived as H, although inefficiently applied due to corruption. Ecotourism and impacts on sea turtles were perceived as VL, because they were deemed unprofitable activities at the individual and community levels. Environmental education was perceived as L, because it centers on nesting, hatching and releasing turtles and is directed at elementary and middle-school students. While fishers perceive a serious negative impact of fishing activities on sea turtles in the San Ignacio-Navachiste-Macapule area, they do not see themselves individually as part of the problem. Achieving sea turtle conservation in this region requires: suitable ecotourism infrastructure, government investments in promotion, and studies to estimate the minimum number of tourists needed to assure profitability. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

77 FR 61426 - Rose Atoll National Wildlife Refuge, American Samoa; Draft Comprehensive Conservation Plan and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-09

... remote sensing system would be set up to monitor nesting seabirds, turtles, and other wildlife... for improved law enforcement oversight and compliance, and remote sensing would also provide better...

77 FR 45571 - Endangered and Threatened Wildlife; 90-Day Finding on a Petition To Delist the Green Turtle in...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-01

... relation to the remainder of the species; and, if discrete, the significance of the population segment to... support their assertion that the Hawaiian population of green turtles is discrete from other green turtle populations, they posit that the Hawaiian population is discrete due to genetic distinction, spatial...

Finding the ‘lost years’ in green turtles: insights from ocean circulation models and genetic analysis

PubMed Central

Putman, Nathan F.; Naro-Maciel, Eugenia

2013-01-01

Organismal movement is an essential component of ecological processes and connectivity among ecosystems. However, estimating connectivity and identifying corridors of movement are challenging in oceanic organisms such as young turtles that disperse into the open sea and remain largely unobserved during a period known as ‘the lost years’. Using predictions of transport within an ocean circulation model and data from published genetic analysis, we present to our knowledge, the first basin-scale hypothesis of distribution and connectivity among major rookeries and foraging grounds (FGs) of green turtles (Chelonia mydas) during their ‘lost years’. Simulations indicate that transatlantic dispersal is likely to be common and that recurrent connectivity between the southwestern Indian Ocean and the South Atlantic is possible. The predicted distribution of pelagic juvenile turtles suggests that many ‘lost years hotspots’ are presently unstudied and located outside protected areas. These models, therefore, provide new information on possible dispersal pathways that link nesting beaches with FGs. These pathways may be of exceptional conservation concern owing to their importance for sea turtles during a critical developmental period. PMID:23945687

Orientation behaviour of leatherback sea turtles within the North Atlantic subtropical gyre.

PubMed

Dodge, Kara L; Galuardi, Benjamin; Lutcavage, Molly E

2015-04-07

Leatherback sea turtles (Dermochelys coriacea) travel thousands of kilometres between temperate feeding and tropical breeding/over-wintering grounds, with adult turtles able to pinpoint specific nesting beaches after multi-year absences. Their extensive migrations often occur in oceanic habitat where limited known sensory information is available to aid in orientation. Here, we examined the migratory orientation of adult male, adult female and subadult leatherbacks during their open-ocean movements within the North Atlantic subtropical gyre by analysing satellite-derived tracks from fifteen individuals over a 2-year period. To determine the turtles' true headings, we corrected the reconstructed tracks for current drift and found negligible differences between current-corrected and observed tracks within the gyre. Individual leatherback headings were remarkably consistent throughout the subtropical gyre, with turtles significantly oriented to the south-southeast. Adult leatherbacks of both sexes maintained similar mean headings and showed greater orientation precision overall. The consistent headings maintained by adult and subadult leatherbacks within the gyre suggest use of a common compass sense. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Antibiotic resistant bacteria as bio-indicator of polluted effluent in the green turtles, Chelonia mydas in Oman.

PubMed

Al-Bahry, Saif N; Mahmoud, Ibrahim Y; Al-Zadjali, Maheera; Elshafie, Abdulkader; Al-Harthy, Asila; Al-Alawi, Wafaa

2011-03-01

Antibiotic resistant bacteria were studied as bio-indicators of marine polluted effluents during egg-laying in green turtles. A non-invasive procedure for sampling oviductal fluid was used to test for exposure of turtles to pollution in Ras Al-Hadd, Oman, which is one of the most important nesting beaches in the world. Each sample was obtained by inserting a 15 cm sterile swab gently into the cloacal vent as the sphincter muscle is relaxed and the cloacal lining is unfolded to the outside. Forty turtles were sampled. A hundred and thirty-two species of bacteria from 7 genera were isolated. The dominant isolate was Citrobacter. Among the isolates 60.6% were multiple resistant to 15 tested antibiotics. The dominant resistance to antibiotics was ampicillin followed by streptomycin and sulphamethoxazole. Sampling oviductal fluid for resistant bacteria to antibiotics is valuable way to assess exposure to polluted effluents during feeding and migratory in turtles. Polluted effluents using bacteria as bio-indicator may influence reproductive potential in this endangered species. Copyright © 2010 Elsevier Ltd. All rights reserved.

The aquatic turtle assemblage inhabiting a highly altered landscape in southeast Missouri

USGS Publications Warehouse

Glorioso, Brad M.; Vaughn, Allison J.; Waddle, J. Hardin

2010-01-01

Turtles are linked to energetic food webs as both consumers of plants and animals and prey for many species. Turtle biomass in freshwater systems can be an order of magnitude greater than that of endotherms. Therefore, declines in freshwater turtle populations can change energy transfer in freshwater systems. Here we report on a mark–recapture study at a lake and adjacent borrow pit in a relict tract of bottomland hardwood forest in the Mississippi River floodplain in southeast Missouri, which was designed to gather baseline data, including sex ratio, size structure, and population size, density, and biomass, for the freshwater turtle population. Using a variety of capture methods, we captured seven species of freshwater turtles (snapping turtle Chelydra serpentina; red-eared slider Trachemys scripta; southern painted turtle Chrysemys dorsalis; river cooter Pseudemys concinna; false map turtle Graptemys pseudogeographica; eastern musk turtle Sternotherus odoratus; spiny softshell Apalone spinifera) comprising four families (Chelydridae, Emydidae, Kinosternidae, Trinoychidae). With the exception of red-eared sliders, nearly all individuals captured were adults. Most turtles were captured by baited hoop-nets, and this was the only capture method that caught all seven species. The unbaited fyke net was very successful in the borrow pit, but only captured four of the seven species. Basking traps and deep-water crawfish nets had minimal success. Red-eared sliders had the greatest population estimate (2,675), density (205/ha), and biomass (178 kg/ha). Two species exhibited a sex-ratio bias: snapping turtles C. serpentina in favor of males, and spiny softshells A. spinifera in favor of females.

Tracking the movements of a post-nesting Southern River Terrapin (Batagur affinis edwardmolli)

NASA Astrophysics Data System (ADS)

Chen, Pelf-Nyok; Wong, Adrian

2015-09-01

A Southern River Terrapin (Batagur affinis edwardmolli) Conservation Project was initiated on one terrapin nesting bank in 2011, following the discovery of a River Terrapin population in the Kemaman River, Terengganu in 2010. Since this project was initiated, Turtle Conservation Society of Malaysia (TCS) was instrumental in the gazettement of three nesting banks along the Kemaman River, from which all River Terrapin eggs are collected for incubation. However, there are at least a dozen other "unprotected" nesting banks along the river, where all eggs were collected for human consumption. This project attempted to determine the movements of a post-nesting River Terrapin, with hopes that it would provide the preliminary baseline information on the utilization of adjacent nesting banks. The solution was a GPS tracking device that transmitted coordinates every hour over cellular networks. Location-based data was sent via Short Message Service (SMS) to our own SMS gateway running on a Raspberry Pi credit-card size computer, which was then logged in a database and presented graphically via Google Maps. It was a complete tracking and monitoring system. This solution enabled researchers to remotely track the movements of a River Terrapin, hence reducing the costs of research. The movements of a post-nesting River Terrapin were tracked for eight days before the battery was drained. On the third day, this River Terrapin ascended an adjacent riverbank and spent less than an hour on the bank, presumably to deposit her remaining eggs. This study confirmed that River Terrapins do utilize other suitable nesting banks if/whenever available. Results from such tracking studies will be used to leverage on the protection of adjacent nesting banks, thus providing greater protection for the critically endangered River Terrapins.

Physiological ecology of overwintering in hatchling turtles.

PubMed

Costanzo, Jon P; Lee, Richard E; Ultsch, Gordon R

2008-07-01

Temperate species of turtles hatch from eggs in late summer. The hatchlings of some species leave their natal nest to hibernate elsewhere on land or under water, whereas others usually remain inside the nest until spring; thus, post-hatching behavior strongly influences the hibernation ecology and physiology of this age class. Little is known about the habitats of and environmental conditions affecting aquatic hibernators, although laboratory studies suggest that chronically hypoxic sites are inhospitable to hatchlings. Field biologists have long been intrigued by the environmental conditions survived by hatchlings using terrestrial hibernacula, especially nests that ultimately serve as winter refugia. Hatchlings are unable to feed, although as metabolism is greatly reduced in hibernation, they are not at risk of starvation. Dehydration and injury from cold are more formidable challenges. Differential tolerances to these stressors may explain variation in hatchling overwintering habits among turtle taxa. Much study has been devoted to the cold-hardiness adaptations exhibited by terrestrial hibernators. All tolerate a degree of chilling, but survival of frost exposure depends on either freeze avoidance through supercooling or freeze tolerance. Freeze avoidance is promoted by behavioral, anatomical, and physiological features that minimize risk of inoculation by ice and ice-nucleating agents. Freeze tolerance is promoted by a complex suite of molecular, biochemical, and physiological responses enabling certain organisms to survive the freezing and thawing of extracellular fluids. Some species apparently can switch between freeze avoidance or freeze tolerance, the mode utilized in a particular instance of chilling depending on prevailing physiological and environmental conditions. (c) 2008 Wiley-Liss, Inc.

Territorial behavior in Taiwanese kukrisnakes (Oligodon formosanus)

PubMed Central

Huang, Wen-San; Greene, Harry W.; Chang, Tien-Jye; Shine, Richard

2011-01-01

The independent evolutionary origin of a complex trait, within a lineage otherwise lacking it, provides a powerful opportunity to test hypotheses on selective forces. Territorial defense of an area containing resources (such as food or shelter) is widespread in lizards but not snakes. Our studies on an insular population of Taiwanese kukrisnakes (Oligodon formosanus) show that females of this species actively defend sea turtle nests by repelling conspecifics for long periods (weeks) until the turtle eggs hatch or are consumed. A clutch of turtle eggs comprises a large, long-lasting food resource, unlike the prey types exploited by other types of snakes. Snakes of this species have formidable weaponry (massively enlarged teeth that are used for slitting eggshells), and when threatened, these snakes wave their tails toward the aggressor (an apparent case of head-tail mimicry). Bites to the tail during intraspecific combat bouts thus can have high fitness costs for males (because the hemipenes are housed in the tail). In combination, unusual features of the species (ability to inflict severe damage to male conspecifics) and the local environment (a persistent prey resource, large relative to the snakes consuming it) render resource defense both feasible and advantageous for female kukrisnakes. The (apparently unique) evolution of territorial behavior in this snake species thus provides strong support for the hypothesis that resource defensibility is critical to the evolution of territoriality. PMID:21502515

Measuring the impact of invasive species on popular culture: a case study based on toy turtles from Japan

USGS Publications Warehouse

Lovich, Jeffrey E.; Yamamoto, Katsuya

2016-01-01

The red-eared slider turtle (Trachemys scripta elegans) is native to portions of the United States of America (USA) and adjacent northeastern Mexico. The bright and colorful hatchlings have long been popular as pets globally but numerous individuals have been released into the wild establishing populations in areas well outside their native range. As a result, slider turtles are now introduced worldwide on all continents, with the exception of Antarctica, and many temperate and tropical islands, including Japan. They are very successful at establishing breeding populations in a variety of habitats, even those in proximity to human development. Once established in large populations, they compete with native turtle species sometimes to the detriment of the latter. Tin toy turtles were popular in Japan for decades, and they were an important export item after World War II. From the 1920s to the 1950s, prior to the widespread establishment of slider populations in Japan, the toys were characterized by muted earth-tone colors representative of native species of Japanese turtles. After the 1950s, toy turtles exhibited brighter combinations of yellow, red and green more typical of slider turtles. This transition may reflect demand for more colorful toys by importing countries like the USA. Alternatively, the change was coincident with the importation of large numbers of colorful slider turtles to Japan via the pet trade and their subsequent establishment and numerical dominance in Japanese wetlands. This switch in toy turtle colors may reflect a cultural transition in awareness of what constitutes the appearance of a typical turtle in Japan. Sliders appear to have been accepted by Japanese consumers as a new cultural norm in the appearance of turtles, a case of art imitating life.

Shading and watering as a tool to mitigate the impacts of climate change in sea turtle nests.

PubMed

Hill, Jacob E; Paladino, Frank V; Spotila, James R; Tomillo, Pilar Santidrián

2015-01-01

Increasing sand temperatures resulting from climate change may negatively impact sea turtle nests by altering sex ratios and decreasing reproductive output. We analyzed the effect of nest shading and watering on sand temperatures as climate mitigation strategies in a beach hatchery at Playa Grande, Costa Rica. We set up plots and placed thermocouples at depths of 45 cm and 75 cm. Half of the plots were shaded and half were exposed to the sun. Within these exposure treatments, we applied three watering treatments over one month, replicating local climatic conditions experienced in this area. We also examined gravimetric water content of sand by collecting sand samples the day before watering began, the day after watering was complete, and one month after completion. Shading had the largest impact on sand temperature, followed by watering and depth. All watering treatments lowered sand temperature, but the effect varied with depth. Temperatures in plots that received water returned to control levels within 10 days after watering stopped. Water content increased at both depths in the two highest water treatments, and 30 days after the end of water application remained higher than plots with low water. While the impacts of watering on sand temperature dissipate rapidly after the end of application, the impacts on water content are much more lasting. Although less effective at lowering sand temperatures than shading, watering may benefit sea turtle clutches by offsetting negative impacts of low levels of rain in particularly dry areas. Prior to implementing such strategies, the natural conditions at the location of interest (e.g. clutch depth, environmental conditions, and beach characteristics) and natural hatchling sex ratios should be taken into consideration. These results provide insight into the effectiveness of nest shading and watering as climate mitigation techniques and illustrate important points of consideration in the crafting of such strategies.

Software for improved field surveys of nesting marine turtles.

PubMed

Anastácio, R; Gonzalez, J M; Slater, K; Pereira, M J

2017-09-07

Field data are still recorded on paper in many worldwide beach surveys of nesting marine turtles. The data must be subsequently transferred into an electronic database, and this can introduce errors in the dataset. To minimize such errors, the "Turtles" software was developed and piloted to record field data by one software user accompanying one Tortuguero in Akumal beaches, Quintana Roo, Mexico, from June 1 st to July 31 st during the night patrols. Comparisons were made between exported data from the software with the paper forms entered into a database (henceforth traditional). Preliminary assessment indicated that the software user tended to record a greater amount of metrics (i.e., an average of 18.3 fields ± 5.4 sd vs. 8.6 fields ± 2.1 sd recorded by the traditional method). The traditional method introduce three types of "errors" into a dataset: missing values in relevant fields (40.1%), different answers for the same value (9.8%), and inconsistent data (0.9%). Only 5.8% of these (missing values) were found with the software methodology. Although only tested by a single user, the software may suggest increased efficacy and warrants further examination to accurately assess the merit of replacing traditional methods of data recording for beach monitoring programmes.

Unravelling the microbiome of eggs of the endangered sea turtle Eretmochelys imbricata identifies bacteria with activity against the emerging pathogen Fusarium falciforme.

PubMed

Sarmiento-Ramírez, Jullie M; van der Voort, Menno; Raaijmakers, Jos M; Diéguez-Uribeondo, Javier

2014-01-01

Habitat bioaugmentation and introduction of protective microbiota have been proposed as potential conservation strategies to rescue endangered mammals and amphibians from emerging diseases. For both strategies, insight into the microbiomes of the endangered species and their habitats is essential. Here, we sampled nests of the endangered sea turtle species Eretmochelys imbricata that were infected with the fungal pathogen Fusarium falciforme. Metagenomic analysis of the bacterial communities associated with the shells of the sea turtle eggs revealed approximately 16,664 operational taxonomic units, with Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes as the most dominant phyla. Subsequent isolation of Actinobacteria from the eggshells led to the identification of several genera (Streptomyces, Amycolaptosis, Micromomospora Plantactinospora and Solwaraspora) that inhibit hyphal growth of the pathogen F. falciforme. These bacterial genera constitute a first set of microbial indicators to evaluate the potential role of microbiota in conservation of endangered sea turtle species.

Potential Applicability of Persuasive Communication to Light-Glow Reduction Efforts: A Case Study of Marine Turtle Conservation

NASA Astrophysics Data System (ADS)

Kamrowski, Ruth L.; Sutton, Stephen G.; Tobin, Renae C.; Hamann, Mark

2014-09-01

Artificial lighting along coastlines poses a significant threat to marine turtles due to the importance of light for their natural orientation at the nesting beach. Effective lighting management requires widespread support and participation, yet engaging the public with light reduction initiatives is difficult because benefits associated with artificial lighting are deeply entrenched within modern society. We present a case study from Queensland, Australia, where an active light-glow reduction campaign has been in place since 2008 to protect nesting turtles. Semi-structured questionnaires explored community beliefs about reducing light and evaluated the potential for using persuasive communication techniques based on the theory of planned behavior (TPB) to increase engagement with light reduction. Respondents ( n = 352) had moderate to strong intentions to reduce light. TPB variables explained a significant proportion of variance in intention (multiple regression: R 2 = 0.54-0.69, P < 0.001), but adding a personal norm variable improved the model ( R 2 = 0.73-0.79, P < 0.001). Significant differences in belief strength between campaign compliers and non-compliers suggest that targeting the beliefs reducing light leads to "increased protection of local turtles" ( P < 0.01) and/or "benefits to the local economy" ( P < 0.05), in combination with an appeal to personal norms, would produce the strongest persuasion potential for future communications. Selective legislation and commitment strategies may be further useful strategies to increase community light reduction. As artificial light continues to gain attention as a pollutant, our methods and findings will be of interest to anyone needing to manage public artificial lighting.

Potential applicability of persuasive communication to light-glow reduction efforts: a case study of marine turtle conservation.

PubMed

Kamrowski, Ruth L; Sutton, Stephen G; Tobin, Renae C; Hamann, Mark

2014-09-01

Artificial lighting along coastlines poses a significant threat to marine turtles due to the importance of light for their natural orientation at the nesting beach. Effective lighting management requires widespread support and participation, yet engaging the public with light reduction initiatives is difficult because benefits associated with artificial lighting are deeply entrenched within modern society. We present a case study from Queensland, Australia, where an active light-glow reduction campaign has been in place since 2008 to protect nesting turtles. Semi-structured questionnaires explored community beliefs about reducing light and evaluated the potential for using persuasive communication techniques based on the theory of planned behavior (TPB) to increase engagement with light reduction. Respondents (n = 352) had moderate to strong intentions to reduce light. TPB variables explained a significant proportion of variance in intention (multiple regression: R (2) = 0.54-0.69, P < 0.001), but adding a personal norm variable improved the model (R (2) = 0.73-0.79, P < 0.001). Significant differences in belief strength between campaign compliers and non-compliers suggest that targeting the beliefs reducing light leads to "increased protection of local turtles" (P < 0.01) and/or "benefits to the local economy" (P < 0.05), in combination with an appeal to personal norms, would produce the strongest persuasion potential for future communications. Selective legislation and commitment strategies may be further useful strategies to increase community light reduction. As artificial light continues to gain attention as a pollutant, our methods and findings will be of interest to anyone needing to manage public artificial lighting.

Thyroid Hormones Reduce Incubation Period without Developmental or Metabolic Costs in Murray River Short-Necked Turtles (Emydura macquarii).

PubMed

McGlashan, Jessica K; Thompson, Michael B; Van Dyke, James U; Spencer, Ricky-John

Metabolic processes are affected by both temperature and thyroid hormones in ectothermic vertebrates. Temperature is the major determinant of incubation length in oviparous vertebrates, but turtles can also alter developmental rate independent of temperature. Temperature gradients within natural nests cause different developmental rates of turtle embryos within nests. Despite temperature-induced reductions in developmental rate, cooler-incubated neonates often hatch synchronously with warmer siblings via metabolic compensation. The physiological mechanisms underlying metabolic compensation are unknown, but thyroid hormones may play a critical role. We applied excess triiodothyronine (T 3 ) to developing eggs of Murray River short-necked turtle (Emydura macquarii)-a species that exhibits metabolic compensation and synchronous hatching-to determine whether T 3 influences developmental rate and whether changes to incubation period incur metabolic costs. We measured heart rate, oxygen consumption and incubation period of eggs, and morphology and performance of hatchlings. Embryos that were exposed to T 3 pipped up to 3.5 d earlier than untreated controls, despite no change in total metabolic expenditure, and there were no treatment differences in hatchling morphology. Hatchlings treated with T 3 demonstrated similar righting ability to hatchlings from the control groups. Exposure to T 3 shortens incubation length by accelerating embryonic development but without statistically increasing embryonic metabolism. Thus, T 3 is a mechanism that cooler-incubated reptiles could use to accelerate their development to allow synchronous hatching with their warmer clutch mates but at little or no metabolic cost. Thus, metabolic compensation for synchronous hatching may not be metabolically expensive if T 3 is the underlying mechanism.

Comparative phylogeny and historical perspectives on population genetics of the Pacific hawksbill (Eretmochelys imbricata) and green turtles (Chelonia mydas), inferred from feeding populations in the Yaeyama Islands, Japan.

PubMed

Nishizawa, Hideaki; Okuyama, Junichi; Kobayashi, Masato; Abe, Osamu; Arai, Nobuaki

2010-01-01

Mitochondrial DNA sequence polymorphisms and patterns of genetic diversity represent the genealogy and relative impacts of historical, geographic, and demographic events on populations. In this study, historical patterns of population dynamics and differentiation in hawksbill (Eretmochelys imbricata) and green turtles (Chelonia mydas) in the Pacific were estimated from feeding populations in the Yaeyama Islands, Japan. Phylogenetic relationships of the haplotypes indicated that hawksbill and green turtles in the Pacific probably underwent very similar patterns and processes of population dynamics over the last million years, with population subdivision during the early Pleistocene and population expansion after the last glacial maximum. These significant contemporary historical events were suggested to have been caused by climatic and sea-level fluctuations. On the other hand, comparing our results to long-term population dynamics in the Atlantic, population subdivisions during the early Pleistocene were specific to Pacific hawksbill and green turtles. Therefore, regional differences in historical population dynamics are suggested. Despite limited sampling locations, these results are the first step in estimating the historical trends in Pacific sea turtles by using phylogenetics and population genetics.

Demographics and density estimates of two three-toed box turtle (Terrapene carolina triunguis) populations within forest and restored prairie sites in central Missouri.

PubMed

O'Connor, Kelly M; Rittenhouse, Chadwick D; Millspaugh, Joshua J; Rittenhouse, Tracy A G

2015-01-01

Box turtles (Terrapene carolina) are widely distributed but vulnerable to population decline across their range. Using distance sampling, morphometric data, and an index of carapace damage, we surveyed three-toed box turtles (Terrapene carolina triunguis) at 2 sites in central Missouri, and compared differences in detection probabilities when transects were walked by one or two observers. Our estimated turtle densities within forested cover was less at the Thomas S. Baskett Wildlife Research and Education Center, a site dominated by eastern hardwood forest (d = 1.85 turtles/ha, 95% CI [1.13, 3.03]) than at the Prairie Fork Conservation Area, a site containing a mix of open field and hardwood forest (d = 4.14 turtles/ha, 95% CI [1.99, 8.62]). Turtles at Baskett were significantly older and larger than turtles at Prairie Fork. Damage to the carapace did not differ significantly between the 2 populations despite the more prevalent habitat management including mowing and prescribed fire at Prairie Fork. We achieved improved estimates of density using two rather than one observer at Prairie Fork, but negligible differences in density estimates between the two methods at Baskett. Error associated with probability of detection decreased at both sites with the addition of a second observer. We provide demographic data on three-toed box turtles that suggest the use of a range of habitat conditions by three-toed box turtles. This case study suggests that habitat management practices and their impacts on habitat composition may be a cause of the differences observed in our focal populations of turtles.

Seasonal heterogeneity of ocean warming: a mortality sink for ectotherm colonizers.

PubMed

Maffucci, Fulvio; Corrado, Raffaele; Palatella, Luigi; Borra, Marco; Marullo, Salvatore; Hochscheid, Sandra; Lacorata, Guglielmo; Iudicone, Daniele

2016-04-05

Distribution shifts are a common adaptive response of marine ectotherms to climate change but the pace of redistribution depends on species-specific traits that may promote or hamper expansion to northern habitats. Here we show that recently, the loggerhead turtle (Caretta caretta) has begun to nest steadily beyond the northern edge of the species' range in the Mediterranean basin. This range expansion is associated with a significant warming of spring and summer sea surface temperature (SST) that offers a wider thermal window suitable for nesting. However, we found that post-hatchlings departing from this location experience low winter SST that may affect their survival and thus hamper the stabilization of the site by self-recruitment. The inspection of the Intergovernmental Panel on Climate Change model projections and observational data on SST trends shows that, despite the annual warming for this century, winter SST show little or no trends. Therefore, thermal constraints during the early developmental phase may limit the chance of population growth at this location also in the near future, despite increasingly favourable conditions at the nesting sites. Quantifying and understanding the interplay between dispersal and environmental changes at all life stages is critical for predicting ectotherm range expansion with climate warming.

Seasonal heterogeneity of ocean warming: a mortality sink for ectotherm colonizers

NASA Astrophysics Data System (ADS)

Maffucci, Fulvio; Corrado, Raffaele; Palatella, Luigi; Borra, Marco; Marullo, Salvatore; Hochscheid, Sandra; Lacorata, Guglielmo; Iudicone, Daniele

2016-04-01

Distribution shifts are a common adaptive response of marine ectotherms to climate change but the pace of redistribution depends on species-specific traits that may promote or hamper expansion to northern habitats. Here we show that recently, the loggerhead turtle (Caretta caretta) has begun to nest steadily beyond the northern edge of the species’ range in the Mediterranean basin. This range expansion is associated with a significant warming of spring and summer sea surface temperature (SST) that offers a wider thermal window suitable for nesting. However, we found that post-hatchlings departing from this location experience low winter SST that may affect their survival and thus hamper the stabilization of the site by self-recruitment. The inspection of the Intergovernmental Panel on Climate Change model projections and observational data on SST trends shows that, despite the annual warming for this century, winter SST show little or no trends. Therefore, thermal constraints during the early developmental phase may limit the chance of population growth at this location also in the near future, despite increasingly favourable conditions at the nesting sites. Quantifying and understanding the interplay between dispersal and environmental changes at all life stages is critical for predicting ectotherm range expansion with climate warming.

Hematology of the Pascagoula map turtle (Graptemys gibbonsi) and the southeast Asian box turtle (Cuora amboinensis).

PubMed

Perpiñán, David; Hernandez-Divers, Sonia M; Latimer, Kenneth S; Akre, Thomas; Hagen, Chris; Buhlmann, Kurt A; Hernandez-Divers, Stephen J

2008-09-01

Turtle populations are decreasing dramatically due to habitat loss and collection for the food and pet market. This study sought to determine hematologic values in two species of turtles to help assess health status of captive and wild populations. Blood samples were collected from 12 individuals of the Pascagoula map turtle (Graptemys gibbonsi) and seven individuals of the southeast Asian box turtle (Cuora amboinensis) from the Savannah River Ecology Laboratory (South Carolina, USA). The hematologic data included hematocrit, total solids, erythrocyte count, leukocyte count, and differential and percentage leukocyte counts. Low hematocrit values and high basophil counts were found in both species. The basophil was the most abundant leukocyte in the Pascagoula map turtle (median = 0.80 x 10(9)/L), whereas in the Southeast Asian box turtle the most abundant leukocyte was the heterophil (median = 2.06 x 10(9)/L).

Embryonic common snapping turtles (Chelydra serpentina) preferentially regulate intracellular tissue pH during acid-base challenges.

PubMed

Shartau, Ryan B; Crossley, Dane A; Kohl, Zachary F; Brauner, Colin J

2016-07-01

The nests of embryonic turtles naturally experience elevated CO2 (hypercarbia), which leads to increased blood PCO2  and a respiratory acidosis, resulting in reduced blood pH [extracellular pH (pHe)]. Some fishes preferentially regulate tissue pH [intracellular pH (pHi)] against changes in pHe; this has been proposed to be associated with exceptional CO2 tolerance and has never been identified in amniotes. As embryonic turtles may be CO2 tolerant based on nesting strategy, we hypothesized that they preferentially regulate pHi, conferring tolerance to severe acute acid-base challenges. This hypothesis was tested by investigating pH regulation in common snapping turtles (Chelydra serpentina) reared in normoxia then exposed to hypercarbia (13 kPa PCO2 ) for 1 h at three developmental ages: 70% and 90% of incubation, and yearlings. Hypercarbia reduced pHe but not pHi, at all developmental ages. At 70% of incubation, pHe was depressed by 0.324 pH units while pHi of brain, white muscle and lung increased; heart, liver and kidney pHi remained unchanged. At 90% of incubation, pHe was depressed by 0.352 pH units but heart pHi increased with no change in pHi of other tissues. Yearlings exhibited a pHe reduction of 0.235 pH units but had no changes in pHi of any tissues. The results indicate common snapping turtles preferentially regulate pHi during development, but the degree of response is reduced throughout development. This is the first time preferential pHi regulation has been identified in an amniote. These findings may provide insight into the evolution of acid-base homeostasis during development of amniotes, and vertebrates in general. © 2016. Published by The Company of Biologists Ltd.

Metals and metalloids in whole blood and tissues of Olive Ridley turtles (Lepidochelys olivacea) from La Escobilla Beach (Oaxaca, Mexico).

PubMed

Cortés-Gómez, Adriana A; Fuentes-Mascorro, Gisela; Romero, Diego

2014-12-15

Concentrations of eight metals and metalloids (Pb, Cd, Cu, Zn, Mn, Se, Ni and As) were evaluated from 41 nesting females (blood) and 13 dead (tissues) Olive Ridley turtles (Lepidochelys olivacea), a species classified as vulnerable and also listed in Appendix I of the Convention of International Trade in Endangered Species (CITES). The mean blood, liver and kidney lead concentration were 0.02 ± 0.01, 0.11 ± 0.08 and 0.06 ± 0.03 μ gg(-1) ww respectively, values lower than other turtle species and locations, which it could be due to the gradual disuse of leaded gasoline in Mexico and Central America since the 1990s. Mean concentration of cadmium was 0.17 ± 0.08 (blood), 82.88 ± 36.65 (liver) and 150.88 ± 110.9 9μg g(-1) (kidney). To our knowledge, the mean renal cadmium levels found is the highest ever reported worldwide for any sea turtle species, while other six elements showed a concentration similar to other studies in sea turtles. Copyright © 2014 Elsevier Ltd. All rights reserved.

Demographics of an ornate box turtle population experiencing minimal human-induced disturbances

USGS Publications Warehouse

Converse, S.J.; Iverson, J.B.; Savidge, J.A.

2005-01-01

Human-induced disturbances may threaten the viability of many turtle populations, including populations of North American box turtles. Evaluation of the potential impacts of these disturbances can be aided by long-term studies of populations subject to minimal human activity. In such a population of ornate box turtles (Terrapene ornata ornata) in western Nebraska, we examined survival rates and population growth rates from 1981-2000 based on mark-recapture data. The average annual apparent survival rate of adult males was 0.883 (SE = 0.021) and of adult females was 0.932 (SE = 0.014). Minimum winter temperature was the best of five climate variables as a predictor of adult survival. Survival rates were highest in years with low minimum winter temperatures, suggesting that global warming may result in declining survival. We estimated an average adult population growth rate (????) of 1.006 (SE = 0.065), with an estimated temporal process variance (????2) of 0.029 (95% CI = 0.005-0.176). Stochastic simulations suggest that this mean and temporal process variance would result in a 58% probability of a population decrease over a 20-year period. This research provides evidence that, unless unknown density-dependent mechanisms are operating in the adult age class, significant human disturbances, such as commercial harvest or turtle mortality on roads, represent a potential risk to box turtle populations. ?? 2005 by the Ecological Society of America.

Three millennia of human and sea turtle interactions in Remote Oceania

NASA Astrophysics Data System (ADS)

Allen, M. S.

2007-12-01

Sea turtles are one of the largest vertebrates in the shallow water ecosystems of Remote Oceania, occurring in both sea grass pastures and on coral reefs. Their functional roles, however, over ecological and evolutionary times scales are not well known, in part because their numbers have been so drastically reduced. Ethnographic and archaeological data is analysed to assess long-term patterns of human sea turtle interactions (mainly green and hawksbill) prior to western contact and the magnitude of turtle losses in this region. From the ethnographic data two large-scale patterns emerge, societies where turtle capture and consumption was controlled by chiefs and priests versus those where control over turtle was more flexible and consumption more egalitarian. Broadly the distinction is between societies on high (volcanic and raised coral) islands versus atolls, but the critical variables are the ratio of land to shallow marine environments, combined with the availability of refugia. Archaeological evidence further highlights differences in the rate and magnitude of turtle losses across these two island types, with high islands suffering both large and rapid declines while those on atolls are less marked. These long-term historical patterns help explain the ethnographic endpoints, with areas that experienced greater losses apparently developing more restrictive social controls over time. Finally, if current turtle migration patterns held in the past, with annual movements between western foraging grounds and eastern nesting beaches, then intensive harvesting from 2,800 Before Present in West Polynesia probably affected turtle abundance and coral reef ecology in East Polynesia well before the actual arrival of human settlers, the latter a process that most likely began 1,400 years later.

Pleated turtle escapes the box--shape changes in Dermochelys coriacea.

PubMed

Davenport, John; Plot, Virginie; Georges, Jean-Yves; Doyle, Thomas K; James, Michael C

2011-10-15

Typical chelonians have a rigid carapace and plastron that form a box-like structure that constrains several aspects of their physiology and ecology. The leatherback sea turtle, Dermochelys coriacea, has a flexible bony carapace strengthened by seven longitudinal ridges, whereas the plastron is reduced to an elliptical outer bony structure, so that the ventrum has no bony support. Measurements of the shell were made on adult female leatherbacks studied on the feeding grounds of waters off Nova Scotia (NS) and on breeding beaches of French Guiana (FG) to examine whether foraging and/or breeding turtles alter carapace size and/or shape. NS turtles exhibited greater mass and girth for a given curved carapace length (CCL) than FG turtles. Girth:CCL ratios rose during the feeding season, indicating increased girth. Measurements were made of the direct (straight) and surface (curved) distances between the medial longitudinal ridge and first right-hand longitudinal ridge (at 50% CCL). In NS turtles, the ratio of straight to curved inter-ridge distances was significantly higher than in FG turtles, indicating distension of the upper surfaces of the NS turtles between the ridges. FG females laid 11 clutches in the breeding season; although CCL and curved carapace width remained stable, girth declined between each nesting episode, indicating loss of mass. Straight to curved inter-ridge distance ratios did not change significantly during the breeding season, indicating loss of dorsal blubber before the onset of breeding. The results demonstrate substantial alterations in size and shape of female D. coriacea over periods of weeks to months in response to alterations in nutritional and reproductive status.

The St. Catherine`s sea turtle conservation program: Modeling effective science education through conservation and research partnerships

DOE Office of Scientific and Technical Information (OSTI.GOV)

March, N.B.; Bishop, G.

1994-12-31

Georgia school teachers served eight to ten day internships as research colleagues on St. Catherine`s island, Georgia. Interns monitored daily nesting activity, evaluated possible nests, validated egg chambers, screened the nests, and monitored each nest daily and assessed hatching success by excavation upon emergence of hatchlings. The real-world, hands-on holistic field experience immersed school teachers in the problems of executing a natural history conservation project integrating scientific content and methodology, mathematical analysis, and computer documentation. Outcomes included increased scientific inquiry, reduced science anxiety, heightened self-confidence, and enhanced credibility with students and colleagues. This educational model is applicable to many areasmore » and problems.« less

Population structure and phylogeography reveal pathways of colonization by a migratory marine reptile (Chelonia mydas) in the central and eastern Pacific.

PubMed

Dutton, Peter H; Jensen, Michael P; Frey, Amy; LaCasella, Erin; Balazs, George H; Zárate, Patricia; Chassin-Noria, Omar; Sarti-Martinez, Adriana Laura; Velez, Elizabeth

2014-11-01

Climate, behavior, ecology, and oceanography shape patterns of biodiversity in marine faunas in the absence of obvious geographic barriers. Marine turtles are an example of highly migratory creatures with deep evolutionary lineages and complex life histories that span both terrestrial and marine environments. Previous studies have focused on the deep isolation of evolutionary lineages (>3 mya) through vicariance; however, little attention has been given to the pathways of colonization of the eastern Pacific and the processes that have shaped diversity within the most recent evolutionary time. We sequenced 770 bp of the mtDNA control region to examine the stock structure and phylogeography of 545 green turtles from eight different rookeries in the central and eastern Pacific. We found significant differentiation between the geographically separated nesting populations and identified five distinct stocks (F ST = 0.08-0.44, P < 0.005). Central and eastern Pacific Chelonia mydas form a monophyletic group containing 3 subclades, with Hawaii more closely related to the eastern Pacific than western Pacific populations. The split between sampled central/eastern and western Pacific haplotypes was estimated at around 0.34 mya, suggesting that the Pacific region west of Hawaii has been a more formidable barrier to gene flow in C. mydas than the East Pacific Barrier. Our results suggest that the eastern Pacific was colonized from the western Pacific via the Central North Pacific and that the Revillagigedos Islands provided a stepping-stone for radiation of green turtles from the Hawaiian Archipelago to the eastern Pacific. Our results fit with a broader paradigm that has been described for marine biodiversity, where oceanic islands, such as Hawaii and Revillagigedo, rather than being peripheral evolutionary "graveyards", serve as sources and recipients of diversity and provide a mechanism for further radiation.

Population structure and phylogeography reveal pathways of colonization by a migratory marine reptile (Chelonia mydas) in the central and eastern Pacific

PubMed Central

Dutton, Peter H; Jensen, Michael P; Frey, Amy; LaCasella, Erin; Balazs, George H; Zárate, Patricia; Chassin-Noria, Omar; Sarti-Martinez, Adriana Laura; Velez, Elizabeth

2014-01-01

Climate, behavior, ecology, and oceanography shape patterns of biodiversity in marine faunas in the absence of obvious geographic barriers. Marine turtles are an example of highly migratory creatures with deep evolutionary lineages and complex life histories that span both terrestrial and marine environments. Previous studies have focused on the deep isolation of evolutionary lineages (>3 mya) through vicariance; however, little attention has been given to the pathways of colonization of the eastern Pacific and the processes that have shaped diversity within the most recent evolutionary time. We sequenced 770 bp of the mtDNA control region to examine the stock structure and phylogeography of 545 green turtles from eight different rookeries in the central and eastern Pacific. We found significant differentiation between the geographically separated nesting populations and identified five distinct stocks (FST = 0.08–0.44, P < 0.005). Central and eastern Pacific Chelonia mydas form a monophyletic group containing 3 subclades, with Hawaii more closely related to the eastern Pacific than western Pacific populations. The split between sampled central/eastern and western Pacific haplotypes was estimated at around 0.34 mya, suggesting that the Pacific region west of Hawaii has been a more formidable barrier to gene flow in C. mydas than the East Pacific Barrier. Our results suggest that the eastern Pacific was colonized from the western Pacific via the Central North Pacific and that the Revillagigedos Islands provided a stepping-stone for radiation of green turtles from the Hawaiian Archipelago to the eastern Pacific. Our results fit with a broader paradigm that has been described for marine biodiversity, where oceanic islands, such as Hawaii and Revillagigedo, rather than being peripheral evolutionary “graveyards”, serve as sources and recipients of diversity and provide a mechanism for further radiation. PMID:25540693

Magnetite in Black Sea Turtles (Chelonia agassizi)

NASA Astrophysics Data System (ADS)

Fuentes, A.; Urrutia-Fucugauchi, J.; Garduño, V.; Sanchez, J.; Rizzi, A.

2004-12-01

Previous studies have reported experimental evidence for magnetoreception in marine turtles. In order to increase our knowledge about magnetoreception and biogenic mineralization, we have isolated magnetite particles from the brain of specimens of black sea turtles Chelonia agassizi. Our samples come from natural deceased organisms collected the reserve area of Colola Maruata in southern Mexico. The occurrence of magnetite particles in brain tissue of black sea turtles offers the opportunity for further studies to investigate possible function of ferrimagnetic material, its mineralogical composition, grain size, texture and its location and structural arrangement within the host tissue. After sample preparation and microscopic examination, we localized and identified the ultrafine unidimensional particles of magnetite by scanning electron microscope (SEM). Particles present grain sizes between 10.0 to 40.0Mm. Our study provides, for the first time, evidence for biogenic formation of this material in the black sea turtles. The ultrafine particles are apparently superparamagnetic. Preliminary results from rock magnetic measurements are also reported and correlated to the SEM observations. The black turtle story on the Michoacan coast is an example of formerly abundant resource which was utilized as a subsistence level by Nahuatl indigenous group for centuries, but which is collapsing because of intensive illegal commercial exploitation. The most important nesting and breeding grounds for the black sea turtle on any mainland shore are the eastern Pacific coastal areas of Maruata and Colola, in Michoacan. These beaches are characterized by important amounts of magnetic mineral (magnetites and titanomagnetites) mixed in their sediments.

78 FR 42921 - Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Northwest...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-18

... Habitat for the Northwest Atlantic Ocean Distinct Population Segment of the Loggerhead Sea Turtle (Caretta... Northwest Atlantic Ocean Distinct Population Segment (DPS) of the Loggerhead Sea Turtle (Caretta caretta... Ocean DPS of the loggerhead sea turtle, its habitat, or previous Federal actions, refer to the proposed...

A comparison of turtle sampling methods in a small lake in Standing Stone State Park, Overton County, Tennessee

USGS Publications Warehouse

Weber, A.; Layzer, James B.

2011-01-01

We used basking traps and hoop nets to sample turtles in Standing Stone Lake at 2-week intervals from May to November 2006. In alternate weeks, we conducted visual basking surveys. We collected and observed four species of turtles: spiny softshell (Apalone spinifera), northern map turtle (Graptemys geographica), pond slider (Trachernys scripta), and snapping turtle (Chelydra serpentina). Relative abundances varied greatly among sampling methods. To varying degrees, all methods were species selective. Population estimates from mark and recaptures of three species, basking counts, and hoop net catches indicated that pond sliders were the most abundant species, but northern map turtles were 8× more abundant than pond sliders in basking trap catches. We saw relatively few snapping turtles basking even though population estimates indicated they were the second most abundant species. Populations of all species were dominated by adult individuals. Sex ratios of three species differed significantly from 1:1. Visual surveys were the most efficient method for determining the presence of species, but capture methods were necessary to obtain size and sex data.

Stable isotopic comparison between loggerhead sea turtle tissues.

PubMed

Vander Zanden, Hannah B; Tucker, Anton D; Bolten, Alan B; Reich, Kimberly J; Bjorndal, Karen A

2014-10-15

Stable isotope analysis has been used extensively to provide ecological information about diet and foraging location of many species. The difference in isotopic composition between animal tissue and its diet, or the diet-tissue discrimination factor, varies with tissue type. Therefore, direct comparisons between isotopic values of tissues are inaccurate without an appropriate conversion factor. We focus on the loggerhead sea turtle (Caretta caretta), for which a variety of tissues have been used to examine diet, habitat use, and migratory origin through stable isotope analysis. We calculated tissue-to-tissue conversions between two commonly sampled tissues. Epidermis and scute (the keratin covering on the carapace) were sampled from 33 adult loggerheads nesting at two beaches in Florida (Casey Key and Canaveral National Seashore). Carbon and nitrogen stable isotope ratios were measured in the epidermis and the youngest portion of the scute tissue, which reflect the isotopic composition of the diet and habitat over similar time periods of the order of several months. Significant linear relationships were observed between the δ(13)C and δ(15)N values of these two tissues, indicating they can be converted reliably. Whereas both epidermis and scute samples are commonly sampled from nesting sea turtles to study trophic ecology and habitat use, the data from these studies have not been comparable without reliable tissue-to-tissue conversions. The equations provided here allow isotopic datasets using the two tissues to be combined in previously published and subsequent studies of sea turtle foraging ecology and migratory movement. In addition, we recommend that future isotopic comparisons between tissues of any organism utilize linear regressions to calculate tissue-to-tissue conversions. Copyright © 2014 John Wiley & Sons, Ltd.

Ecological and evolutionary significance of a lack of capacity for extended developmental arrest in crocodilian eggs

PubMed Central

Evans, Roger G.; Manolis, S. Charlie; Webb, Grahame J.; Reina, Richard D.

2017-01-01

Hypoxia within the oviducts maintains embryonic arrest in turtles at the pre-ovipositional stage, which expands the timeframe over which nesting can occur without compromising embryo survival. The arrest can be extended post-oviposition through incubation of eggs in hypoxia. We determined whether crocodilian embryos have this same capacity. We also tested whether increased oxygen availability during incubation alters hatching success. We incubated freshly laid saltwater crocodile (Crocodylus porosus) eggs (N = 83) at 32°C in one of five treatments; control (normoxia; 21% O2), 3-day and 6-day hypoxia (1% O2), or 3-day and 6-day hyperoxia (42% O2). Incubation (approx. 82 days) was then completed in normoxia. There was a significant effect of treatment on survival of embryos through to hatching (p < 0.001). The hypoxic treatments resulted in almost no hatching (6.7% and 0% survival for the 3- and 6-day treatments, respectively), while the hyperoxic and control treatments resulted in normal to high hatching success (86.6%, 100% and 64.2% for the control, 3- and 6-day hyperoxic treatments, respectively). Unlike turtles, hypoxic incubation of crocodile eggs failed to delay development. Our results provide the first experimental evidence that, unlike turtles, crocodiles do not exhibit embryonic arrest when incubated under hypoxic conditions immediately following oviposition. An absence of embryonic arrest is of ecological and evolutionary significance, as it implies that crocodilians lack an ability to avoid adverse environmental conditions through delayed nesting and that, unlike turtles, embryonic arrest may not be a potential explanation for the lack of viviparity in the order Crocodylia. PMID:29308266

Effects of habitat fragmentation on a stream-dwelling species, the flattened musk turtle Sternotherus depressus

USGS Publications Warehouse

Dodd, C.K.

1990-01-01

The flattened musk turtle Sternotherus depressus has disappeared from more than half of its former range because of habitat modifications to stream and river channels in the Warrior River Basin, Alabama. Only 6·9% of its probable historic range contains relatively healthy populations, and most populations are fragmented by extensive areas of unsuitable habitat. Turtles in the best remaining habitats continue to be vulnerable to disease and human-related disturbance, collecting and habitat modification. These factors lead to population declines and abnormal population structure. Habitat fragmentation, especially in small populations, increases vulnerability to human-caused catastrophes and demographic accidents, and could lead to eventual extinction. The threats facing fragmented populations of this turtle probably parallel those affecting many other stream-dwelling species throughout the southeastern United States.

Adaptations to terrestrial overwintering of hatchling northern map turtles, Graptemys geographica.

PubMed

Baker, P J; Costanzo, J P; Iverson, J B; Lee, R E

2003-11-01

We conducted a 3-year field and laboratory study of winter biology in hatchlings of the northern map turtle ( Graptemys geographica). At our study area in northern Indiana, hatchlings routinely overwintered in their natal nests, emerging after the weather warmed in spring. Winter survival was excellent despite the fact that hatchlings were exposed frequently to subfreezing temperatures (to -5.4 degrees C). In the laboratory, cold-acclimated hatchlings exhibited low rates of evaporative water loss (mean=2.0 mg g(-1) day(-1)), which would enable them to conserve body water during winter. Laboratory-reared hatchlings were intolerant of freezing at -2.5 degrees C for 24 h, conditions that are readily survived by freeze-tolerant species of turtles. Winter survival of hatchling G. geographica probably depended on their extensive capacity for supercooling (to -14.8 degrees C) and their well-developed resistance to inoculative freezing, which may occur when hatchlings contact ice and ice-nucleating agents present in nesting soil. Supercooled hatchlings survived a brief exposure to -8 degrees C. Others, held at -6 degrees C for 5 days, maintained ATP concentrations at control levels, although they did accumulate lactate and glucose, probably in response to tissue hypoxia. Therefore, anoxia tolerance, as evidenced by the viability of hatchlings exposed to N(2) gas for 8 days, may promote survival during exposure to subfreezing temperatures.

Dietary shift of an invasive predator: rats, seabirds and sea turtles

PubMed Central

Caut, Stéphane; Angulo, Elena; Courchamp, Franck

2008-01-01

Rats have reached about 80% of the world's islands and are among the most successful invasive mammals. Rats are opportunistic predators that are notorious for their impact on a variety of animal and plant species. However, little documented evidence on the complexities of these interactions is available.In our study, we assessed the impact of black rats Rattus rattus introduced on a small uninhabited island with a relatively simple ecosystem, Surprise Island, New Caledonia. We also compared the diet of R. rattus in the presence and absence of breeding seabirds, assessing the dietary compensation for this potentially important food source. From 2002 to 2005, we used live trapping studies combined with stable isotope analysis and conventional diet analyses (direct observations, gut and faecal contents) to characterize the diet of rats.Our results suggest a heavy predatory impact on seabirds, which could constitute as much as 24% of the rat diet. Moreover, in the absence of birds, rats compensated marginally by preying more heavily on other components of their diet but mostly acquired a new resource. They shifted their diet by preying heavily upon another endangered species, the hatchlings of sea turtles Chelonia mydas, which could constitute the main resource in the diet of R. rattus in those periods. Abundance, body condition and distribution of the rats were consistent with heavy predation upon this additional resource.Synthesis and applications. In island ecosystems invasive rats prey mainly upon seabird eggs and chicks, thereby threatening their populations. Although rats are certainly capable of surviving on terrestrial foods outside the seabird nesting season, their ability to prey upon ephemeral but abundant resources, such as hatchling sea turtles, may contribute to maintaining their populations. This may explain their success on Surprise Island, an ecosystem of extreme conditions, and suggests that biologists and managers working with threatened species should be aware of the possibility of temporary diet shifts by introduced rodents that may cause unexpected heavy predation on these species. This dietary shift from one endangered taxa to another has major implications for the conservation of seabirds and sea turtles world-wide and more generally for the biodiversity of invaded insular communities. PMID:18784794

Accidental bait: do deceased fish increase freshwater turtle bycatch in commercial fyke nets?

PubMed

Larocque, Sarah M; Watson, Paige; Blouin-Demers, Gabriel; Cooke, Steven J

2012-07-01

Bycatch of turtles in passive inland fyke net fisheries has been poorly studied, yet bycatch is an important conservation issue given the decline in many freshwater turtle populations. Delayed maturity and low natural adult mortality make turtles particularly susceptible to population declines when faced with additional anthropogenic adult mortality such as bycatch. When turtles are captured in fyke nets, the prolonged submergence can lead to stress and subsequent drowning. Fish die within infrequently checked passive fishing nets and dead fish are a potential food source for many freshwater turtles. Dead fish could thus act as attractants and increase turtle captures in fishing nets. We investigated the attraction of turtles to decomposing fish within fyke nets in eastern Ontario. We set fyke nets with either 1 kg of one-day or five-day decomposed fish, or no decomposed fish in the cod-end of the net. Decomposing fish did not alter the capture rate of turtles or fish, nor did it alter the species composition of the catch. Thus, reducing fish mortality in nets using shorter soak times is unlikely to alter turtle bycatch rates since turtles were not attracted by the dead fish. Interestingly, turtle bycatch rates increased as water temperatures did. Water temperature also influences turtle mortality by affecting the duration turtles can remain submerged. We thus suggest that submerged nets to either not be set or have reduced soak times in warm water conditions (e.g., >20 °C) as turtles tend to be captured more frequently and cannot withstand prolonged submergence.

Foraging area fidelity for Kemp's ridleys in the Gulf of Mexico.

PubMed

Shaver, Donna J; Hart, Kristen M; Fujisaki, Ikuko; Rubio, Cynthia; Sartain, Autumn R; Peña, Jaime; Burchfield, Patrick M; Gamez, Daniel Gomez; Ortiz, Jaime

2013-07-01

For many marine species, locations of key foraging areas are not well defined. We used satellite telemetry and switching state-space modeling (SSM) to identify distinct foraging areas used by Kemp's ridley turtles (Lepidochelys kempii) tagged after nesting during 1998-2011 at Padre Island National Seashore, Texas, USA (PAIS; N = 22), and Rancho Nuevo, Tamaulipas, Mexico (RN; N = 9). Overall, turtles traveled a mean distance of 793.1 km (±347.8 SD) to foraging sites, where 24 of 31 turtles showed foraging area fidelity (FAF) over time (N = 22 in USA, N = 2 in Mexico). Multiple turtles foraged along their migratory route, prior to arrival at their "final" foraging sites. We identified new foraging "hotspots" where adult female Kemp's ridley turtles spent 44% of their time during tracking (i.e., 2641/6009 tracking days in foraging mode). Nearshore Gulf of Mexico waters served as foraging habitat for all turtles tracked in this study; final foraging sites were located in water <68 m deep and a mean distance of 33.2 km (±25.3 SD) from the nearest mainland coast. Distance to release site, distance to mainland shore, annual mean sea surface temperature, bathymetry, and net primary production were significant predictors of sites where turtles spent large numbers of days in foraging mode. Spatial similarity of particular foraging sites selected by different turtles over the 13-year tracking period indicates that these areas represent critical foraging habitat, particularly in waters off Louisiana. Furthermore, the wide distribution of foraging sites indicates that a foraging corridor exists for Kemp's ridleys in the Gulf. Our results highlight the need for further study of environmental and bathymetric components of foraging sites and prey resources contained therein, as well as international cooperation to protect essential at-sea foraging habitats for this imperiled species.

Foraging area fidelity for Kemp's ridleys in the Gulf of Mexico

USGS Publications Warehouse

Shaver, Donna J.; Hart, Kristen M.; Fujisaki, Ikuko; Rubio, Cynthia; Sartain-Iverson, Autumn R.; Peña, Jaime; Burchfield, Patrick M.; Gamez, Daniel Gomez; Ortiz, Jaime

2013-01-01

For many marine species, locations of key foraging areas are not well defined. We used satellite telemetry and switching state-space modeling (SSM) to identify distinct foraging areas used by Kemp's ridley turtles (Lepidochelys kempii) tagged after nesting during 1998–2011 at Padre Island National Seashore, Texas, USA (PAIS; N = 22), and Rancho Nuevo, Tamaulipas, Mexico (RN; N = 9). Overall, turtles traveled a mean distance of 793.1 km (±347.8 SD) to foraging sites, where 24 of 31 turtles showed foraging area fidelity (FAF) over time (N = 22 in USA, N = 2 in Mexico). Multiple turtles foraged along their migratory route, prior to arrival at their "final" foraging sites. We identified new foraging "hotspots" where adult female Kemp's ridley turtles spent 44% of their time during tracking (i.e., 2641/6009 tracking days in foraging mode). Nearshore Gulf of Mexico waters served as foraging habitat for all turtles tracked in this study; final foraging sites were located in water <68 m deep and a mean distance of 33.2 km (±25.3 SD) from the nearest mainland coast. Distance to release site, distance to mainland shore, annual mean sea surface temperature, bathymetry, and net primary production were significant predictors of sites where turtles spent large numbers of days in foraging mode. Spatial similarity of particular foraging sites selected by different turtles over the 13-year tracking period indicates that these areas represent critical foraging habitat, particularly in waters off Louisiana. Furthermore, the wide distribution of foraging sites indicates that a foraging corridor exists for Kemp's ridleys in the Gulf. Our results highlight the need for further study of environmental and bathymetric components of foraging sites and prey resources contained therein, as well as international cooperation to protect essential at-sea foraging habitats for this imperiled species.

Reproduction in shark-attacked sea turtles is supported by stress-reduction mechanisms.

PubMed Central

Jessop, Tim; Sumner, Joanna; Lance, Val; Limpus, Col

2004-01-01

Vertebrates exhibit varied behavioural and physiological tactics to promote reproductive success. We examined mechanisms that could enable female loggerhead turtles to undertake nesting activities and maintain seasonal reproduction despite recent shark injuries of varying severity. We proposed that endocrinal mechanisms that regulate both a turtle's stress response and reproductive ability are modified to promote successful and continued reproduction. Irrespective of the degree of injury, females did not exhibit increased levels of the stress hormone corticosterone, nor decreased levels of the reproductive steroid testosterone; hormone responses consistent with stress. When exposed to a capture stressor, females with shark injury did not exhibit any greater corticosterone response than controls. In addition, breeding females showed a reduced corticosterone stress response compared to non-breeding females. Reduced endocrinal responses following shark injury, and during breeding in general may, in part, enable females to maintain behavioural and physiological commitment to reproduction. PMID:15101429

77 FR 27411 - Sea Turtle Conservation; Shrimp Trawling Requirements

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-10

.... 120328230-1019-01] RIN 0648-BC10 Sea Turtle Conservation; Shrimp Trawling Requirements AGENCY: National... proposed rule is to reduce incidental bycatch and mortality of sea turtles in the southeastern U.S. shrimp fisheries, and to aid in the protection and recovery of listed sea turtle populations. DATES: Written...

75 FR 70900 - Proposed Information Collection; Comment Request; Reporting of Sea Turtle Entanglement in Fishing...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

... Collection; Comment Request; Reporting of Sea Turtle Entanglement in Fishing Gear or Marine Debris AGENCY... sea turtles becoming accidentally entangled in active or discarded fixed fishing gear or marine debris. These entanglements may prevent the recovery of endangered and threatened sea turtle populations. The...

Managing conflicts between economic activities and threatened migratory marine species toward creating a multiobjective blue economy.

PubMed

Harris, Linda R; Nel, Ronel; Oosthuizen, Herman; Meÿer, Mike; Kotze, Deon; Anders, Darrell; McCue, Steven; Bachoo, Santosh

2018-04-01

Harnessing the economic potential of the oceans is key to combating poverty, enhancing food security, and strengthening economies. But the concomitant risk of intensified resource extraction to migratory species is worrying given these species contribute to important ecological processes, often underpin alternative livelihoods, and are mostly already threatened. We thus sought to quantify the potential conflict between key economic activities (5 fisheries and hydrocarbon exploitation) and sea turtle migration corridors in a region with rapid economic development: southern and eastern Africa. We satellite tracked the movement of 20 loggerhead (Caretta caretta) and 14 leatherback (Dermochelys coriacea) turtles during their postnesting migrations. We used movement-based kernel density estimation to identify migration corridors for each species. We overlaid these corridors on maps of the distribution and intensity of economic activities, quantified the extent of overlap and threat posed by each activity on each species, and compared the effects of activities. These results were compared with annual bycatch rates in the respective fisheries. Both species' 3 corridors overlapped most with longline fishing, but the effect was worse for leatherbacks: their bycatch rates of approximately 1500/year were substantial relative to the regional population size of <100 nesting females/annum. This bycatch rate is likely slowing population growth. Artisanal fisheries may be of greater concern for loggerheads than for leatherbacks, but the population appears to be withstanding the high bycatch rates because it is increasing exponentially. The hydrocarbon industry currently has a moderately low impact on both species, but mining in key areas (e.g., Southern Mozambique) may undermine >50 years of conservation, potentially affecting >80% of loggerheads, 33% of the (critically endangered) leatherbacks, and their nesting beaches. We support establishing blue economies (i.e., generating wealth from the ocean), but oceans need to be carefully zoned and responsibly managed in both space and time to achieve economic (resource extraction), ecological (conservation, maintenance of processes), and social (maintenance of alternative livelihood opportunities, alleviate poverty) objectives. © 2017 Society for Conservation Biology.

Large Aquatic Ecosystem Restoration Monitoring for Decision Makers: Monitoring to Target and Evaluate Success of Ecosystem Restoration

EPA Science Inventory

Monitoring ecosystem restoration at various scales in LAEs can be challenging, frustrating and rewarding. Some of the major ecosystem restoration monitoring occurring in LAEs include: seagrass expansion/contraction; dead zone sizes; oyster reefs; sea turtle nesting; toxic and nu...

Animals and How They Live.

ERIC Educational Resources Information Center

National Audubon Society, New York, NY.

This set of teaching aids consists of 14 Audubon Nature Bulletins, providing teachers and students with informational reading on animals. The bulletin titles are as follows: Birds: Their Adaptations to Ways of Life; Our Friends the Hawks; Mysteries of Bird Migration; Bird Nests; Camouflage in the Animal World; Snakes; Turtles; Frogs and Toads;…

The Voice of the Turtle Dove.

ERIC Educational Resources Information Center

Terkel, Amelia S.

1985-01-01

Suggests using ring doves in the classroom for observing behavior patterns and the entire reproductive cycle. Requirements for space, food, and care are minimal and easily obtained. Students can observe: male participation in nest-building; care of young; and (using candlelight) embryos and heartbeats because of the thin egg shells these birds…

Three Novel Herpesviruses of Endangered Clemmys and Glyptemys Turtles

PubMed Central

Ossiboff, Robert J.; Raphael, Bonnie L.; Ammazzalorso, Alyssa D.; Seimon, Tracie A.; Newton, Alisa L.; Chang, Tylis Y.; Zarate, Brian; Whitlock, Alison L.; McAloose, Denise

2015-01-01

The rich diversity of the world’s reptiles is at risk due to significant population declines of broad taxonomic and geographic scope. Significant factors attributed to these declines include habitat loss, pollution, unsustainable collection and infectious disease. To investigate the presence and significance of a potential pathogen on populations of critically endangered bog turtles (Glyptemys muhlenbergii) as well sympatric endangered wood (G. insculpta) and endangered spotted (Clemmys guttata) turtles in the northeastern United States, choanal and cloacal swabs collected from 230 turtles from 19 sites in 5 states were screened for herpesvirus by polymerase chain reaction. We found a high incidence of herpesvirus infection in bog turtles (51.5%; 105/204) and smaller numbers of positive wood (5) and spotted (1) turtles. Sequence and phylogenetic analysis revealed three previously uncharacterized alphaherpesviruses. Glyptemys herpesvirus 1 was the predominant herpesvirus detected and was found exclusively in bog turtles in all states sampled. Glyptemys herpesvirus 2 was found only in wood turtles. Emydid herpesvirus 2 was found in a small number of bog turtles and a single spotted turtle from one state. Based on these findings, Glyptemys herpesvirus 1 appears to be a common infection in the study population, whereas Glyptemys herpesvirus 2 and Emydid herpesvirus 2 were not as frequently detected. Emydid herpesvirus 2 was the only virus detected in more than one species. Herpesviruses are most often associated with subclinical or mild infections in their natural hosts, and no sampled turtles showed overt signs of disease at sampling. However, infection of host-adapted viruses in closely related species can result in significant disease. The pathogenic potential of these viruses, particularly Emydid herpesvirus 2, in sympatric chelonians warrants additional study in order to better understand the relationship of these viruses with their endangered hosts. PMID:25875510

Three novel herpesviruses of endangered Clemmys and Glyptemys turtles.

PubMed

Ossiboff, Robert J; Raphael, Bonnie L; Ammazzalorso, Alyssa D; Seimon, Tracie A; Newton, Alisa L; Chang, Tylis Y; Zarate, Brian; Whitlock, Alison L; McAloose, Denise

2015-01-01

The rich diversity of the world's reptiles is at risk due to significant population declines of broad taxonomic and geographic scope. Significant factors attributed to these declines include habitat loss, pollution, unsustainable collection and infectious disease. To investigate the presence and significance of a potential pathogen on populations of critically endangered bog turtles (Glyptemys muhlenbergii) as well sympatric endangered wood (G. insculpta) and endangered spotted (Clemmys guttata) turtles in the northeastern United States, choanal and cloacal swabs collected from 230 turtles from 19 sites in 5 states were screened for herpesvirus by polymerase chain reaction. We found a high incidence of herpesvirus infection in bog turtles (51.5%; 105/204) and smaller numbers of positive wood (5) and spotted (1) turtles. Sequence and phylogenetic analysis revealed three previously uncharacterized alphaherpesviruses. Glyptemys herpesvirus 1 was the predominant herpesvirus detected and was found exclusively in bog turtles in all states sampled. Glyptemys herpesvirus 2 was found only in wood turtles. Emydid herpesvirus 2 was found in a small number of bog turtles and a single spotted turtle from one state. Based on these findings, Glyptemys herpesvirus 1 appears to be a common infection in the study population, whereas Glyptemys herpesvirus 2 and Emydid herpesvirus 2 were not as frequently detected. Emydid herpesvirus 2 was the only virus detected in more than one species. Herpesviruses are most often associated with subclinical or mild infections in their natural hosts, and no sampled turtles showed overt signs of disease at sampling. However, infection of host-adapted viruses in closely related species can result in significant disease. The pathogenic potential of these viruses, particularly Emydid herpesvirus 2, in sympatric chelonians warrants additional study in order to better understand the relationship of these viruses with their endangered hosts.

Body temperature stability achieved by the large body mass of sea turtles.

PubMed

Sato, Katsufumi

2014-10-15

To investigate the thermal characteristics of large reptiles living in water, temperature data were continuously recorded from 16 free-ranging loggerhead turtles, Caretta caretta, during internesting periods using data loggers. Core body temperatures were 0.7-1.7°C higher than ambient water temperatures and were kept relatively constant. Unsteady numerical simulations using a spherical thermodynamic model provided mechanistic explanations for these phenomena, and the body temperature responses to fluctuating water temperature can be simply explained by a large body mass with a constant thermal diffusivity and a heat production rate rather than physiological thermoregulation. By contrast, body temperatures increased 2.6-5.1°C in 107-152 min during their emergences to nest on land. The estimated heat production rates on land were 7.4-10.5 times the calculated values in the sea. The theoretical prediction that temperature difference between body and water temperatures would increase according to the body size was confirmed by empirical data recorded from several species of sea turtles. Comparing previously reported data, the internesting intervals of leatherback, green and loggerhead turtles were shorter when the body temperatures were higher. Sea turtles seem to benefit from a passive thermoregulatory strategy, which depends primarily on the physical attributes of their large body masses. © 2014. Published by The Company of Biologists Ltd.

The influence of disturbance events on survival and dispersal rates of Florida box turtles

USGS Publications Warehouse

Dodd, C.K.; Ozgul, A.; Oli, M.K.

2006-01-01

Disturbances have the potential to cause long-term effects to ecosystem structure and function, and they may affect individual species in different ways. Long-lived vertebrates such as turtles may be at risk from such events, inasmuch as their life histories preclude rapid recovery should extensive mortality occur. We applied capture–mark–recapture models to assess disturbance effects on a population of Florida box turtles (Terrapene carolina bauri) on Egmont Key, Florida, USA. Near the midpoint of the study, a series of physical disturbances affected the island, from salt water overwash associated with several tropical storms to extensive removal of nonindigenous vegetation. These disturbances allowed us to examine demographic responses of the turtle population and to determine if they affected dispersal throughout the island. Adult survival rates did not vary significantly either between sexes or among years of the study. Survival rates did not vary significantly between juvenile and adult turtles, or among years of the study. Furthermore, neither adult nor juvenile survival rates differed significantly between pre- and post-disturbance. However, dispersal rates varied significantly among the four major study sites, and dispersal rates were higher during the pre-disturbance sampling periods compared to post-disturbance. Our results suggest few long-term effects on the demography of the turtle population. Florida box turtles responded to tropical storms and vegetation control by moving to favorable habitats minimally affected by the disturbances and remaining there. As long as turtles and perhaps other long-lived vertebrates can disperse to non-disturbed habitat, and high levels of mortality do not occur in a population, a long life span may allow them to wait out the impact of disturbance with potentially little effect on long-term population processes.

Conservation genomics of the endangered Burmese roofed turtle.

PubMed

Çilingir, F Gözde; Rheindt, Frank E; Garg, Kritika M; Platt, Kalyar; Platt, Steven G; Bickford, David P

2017-12-01

The Burmese roofed turtle (Batagur trivittata) is one of the world's most endangered turtles. Only one wild population remains in Myanmar. There are thought to be 12 breeding turtles in the wild. Conservation efforts for the species have raised >700 captive turtles since 2002, predominantly from eggs collected in the wild. We collected tissue samples from 445 individuals (approximately 40% of the turtles' remaining global population), applied double-digest restriction-site associated DNA sequencing (ddRAD-Seq), and obtained approximately 1500 unlinked genome-wide single nucleotide polymorphisms. Individuals fell into 5 distinct genetic clusters, 4 of which represented full-sib families. We inferred a low effective population size (≤10 individuals) but did not detect signs of severe inbreeding, possibly because the population bottleneck occurred recently. Two groups of 30 individuals from the captive pool that were the most genetically diverse were reintroduced to the wild, leading to an increase in the number of fertile eggs (n = 27) in the wild. Another 25 individuals, selected based on the same criteria, were transferred to the Singapore Zoo as an assurance colony. Our study demonstrates that the research-to-application gap in conservation can be bridged through application of cutting-edge genomic methods. © 2017 Society for Conservation Biology.

Populations and home range relationships of the box turtle, Terrapene carolina (Linnaeus)

USGS Publications Warehouse

Stickel, L.F.

1949-01-01

A population study of Terrapene carolina (Linnaeus) was made at the Patuxent Research Refuge, Maryland, from 1944 to 1947. A thirty acre area in bottomland forest was selected for intensive study. Turtles were marked by filing notches in marginal scutes according to a code. Turtles make extensive use of brushy shelter during the day as well.as at night. Gully banks and woods openings are used for sunning. Nights are usually spent in a 'form,' constructed by the turtle in leaves, debris, or earth. A form may be used once or it may be used repeatedly by the same or different turtles. Weather conditions most favorable to turtle activity are high humidity, warm sunny days, and frequent rains. Periods of activity are alternated with periods of quiet, even in favorable weather. There is no evidence for territorialism. Ranges of turtles of all ages and both sexes overlap grossly. Turtles are frequently found near each other but no antagonistic behavior has been observed. Adult turtles occupy specific home ranges which they maintain from year to year. Turtles retained their ranges even though a flood that completely covered the study area. Maximum home range diameters were determined by measurements of the mapped ranges of individual turtles. There was no significant difference between sizes of male and female ranges: males 33O+ 26 feet, females 37O+29 feet. A trail-laying device was used in following travel routes for 456 turtle days. Normal movements within the home range are characterized by (1) turns, doublings, detours, and criss-crossing paths, (2) interspersion of fairly direct traverses of the home range, (3) frequently repeated travels over certain routes. Maximum limits of the home range are ordinarily reached within a few days or weeks, although some turtles cover only one portion of the range at a time. Some turtles have two home ranges. One of these turtles was followed with a trailer for 161 days in 1946 and 1947. Trips outside the home range are made by females for egg laying. Trips of unexplained nature are made by both males and females. Turtles from other areas are occasional transients through the study plot. Standardized census trips provided data for estimating the size of the population. Census data were taken after females had returned from egg laying. The samples were spaced at intervals of a week or more to allow free movement of turtles over their ranges and assure more nearly equal availability of all turtles. These standard samples were compared by a collection ratio. Assumptions involved in the use of this ratio are discussed. Correction factors were applied to make allowance for turtles whose ranges.were partly inside and partly outside the study area, and for transient turtles. A second estimate, on the basis of the entire season's collecting, gave closely comparable results. The population of the study area is estimated to be between four and five turtles per acre, with juveniles constituting less than ten per cent of the total.

Clinical Pathology Reference Intervals for an In-Water Population of Juvenile Loggerhead Sea Turtles (Caretta caretta) in Core Sound, North Carolina, USA

PubMed Central

Kelly, Terra R.; McNeill, Joanne Braun; Avens, Larisa; Hall, April Goodman; Goshe, Lisa R.; Hohn, Aleta A.; Godfrey, Matthew H.; Mihnovets, A. Nicole; Cluse, Wendy M.; Harms, Craig A.

2015-01-01

The loggerhead sea turtle (Caretta caretta) is found throughout the waters of the Atlantic, Pacific, and Indian Oceans. It is a protected species throughout much of its range due to threats such as habitat loss, fisheries interactions, hatchling predation, and marine debris. Loggerheads that occur in the southeastern U.S. are listed as “threatened” on the U.S. Endangered Species List, and receive state and federal protection. As part of an on-going population assessment conducted by the National Marine Fisheries Service, samples were collected from juvenile loggerhead sea turtles in Core Sound, North Carolina, between 2004 and 2007 to gain insight on the baseline health of the threatened Northwest Atlantic Ocean population. The aims of the current study were to establish hematologic and biochemical reference intervals for this population, and to assess variation of the hematologic and plasma biochemical analytes by season, water temperature, and sex and size of the turtles. Reference intervals for the clinical pathology parameters were estimated following Clinical Laboratory Standards Institute guidelines. Season, water temperature, sex, and size of the turtles were found to be significant factors of variation for parameter values. Seasonal variation could be attributed to physiological effects of decreasing photoperiod, cooler water temperature, and migration during the fall months. Packed cell volume, total protein, and albumin increased with increasing size of the turtles. The size-related differences in analytes documented in the present study are consistent with other reports of variation in clinical pathology parameters by size and age in sea turtles. As a component of a health assessment of juvenile loggerhead sea turtles in North Carolina, this study will serve as a baseline aiding in evaluation of trends for this population and as a diagnostic tool for assessing the health and prognosis for loggerhead sea turtles undergoing rehabilitation. PMID:25738772

Clinical pathology reference intervals for an in-water population of juvenile loggerhead sea turtles (Caretta caretta) in Core Sound, North Carolina, USA.

PubMed

Kelly, Terra R; McNeill, Joanne Braun; Avens, Larisa; Hall, April Goodman; Goshe, Lisa R; Hohn, Aleta A; Godfrey, Matthew H; Mihnovets, A Nicole; Cluse, Wendy M; Harms, Craig A

2015-01-01

The loggerhead sea turtle (Caretta caretta) is found throughout the waters of the Atlantic, Pacific, and Indian Oceans. It is a protected species throughout much of its range due to threats such as habitat loss, fisheries interactions, hatchling predation, and marine debris. Loggerheads that occur in the southeastern U.S. are listed as "threatened" on the U.S. Endangered Species List, and receive state and federal protection. As part of an on-going population assessment conducted by the National Marine Fisheries Service, samples were collected from juvenile loggerhead sea turtles in Core Sound, North Carolina, between 2004 and 2007 to gain insight on the baseline health of the threatened Northwest Atlantic Ocean population. The aims of the current study were to establish hematologic and biochemical reference intervals for this population, and to assess variation of the hematologic and plasma biochemical analytes by season, water temperature, and sex and size of the turtles. Reference intervals for the clinical pathology parameters were estimated following Clinical Laboratory Standards Institute guidelines. Season, water temperature, sex, and size of the turtles were found to be significant factors of variation for parameter values. Seasonal variation could be attributed to physiological effects of decreasing photoperiod, cooler water temperature, and migration during the fall months. Packed cell volume, total protein, and albumin increased with increasing size of the turtles. The size-related differences in analytes documented in the present study are consistent with other reports of variation in clinical pathology parameters by size and age in sea turtles. As a component of a health assessment of juvenile loggerhead sea turtles in North Carolina, this study will serve as a baseline aiding in evaluation of trends for this population and as a diagnostic tool for assessing the health and prognosis for loggerhead sea turtles undergoing rehabilitation.

Hierarchical, quantitative biogeographic provinces for all North American turtles and their contribution to the biogeography of turtles and the continent

USGS Publications Warehouse

Ennen, Joshua R.; Matamoros, Wilfredo A.; Agha, Mickey; Lovich, Jeffrey E.; Sweat, Sarah C.; Hoagstrom, Christopher W.

2017-01-01

Our study represents the first attempt to describe biogeographic provinces for North American (México, United States, and Canada) turtles. We analyzed three nested data sets separately: (1) all turtles, (2) freshwater turtles, and (3) aquatic turtles. We georeferenced North American turtle distributions, then we created presence–absence matrices for each of the three data sets. We used watershed unit as biogeographic units. We conducted an unweighted pair-group method with arithmetic mean clustering analysis on each Jaccard index distance matrix from our watershed species matrices to delineate biogeographic provinces. Provinces were then tested for significant differences in species compositions in a global model with the use of a one-way analysis of similarity. We conducted a best subset of environmental variables with maximum (rank) correlation with community dissimilarities that determined the best model of abiotic variables explaining province delineation (i.e., climate, topography, and stream channel). To identify which species contributed the most to province delineations, we conducted an indicator species analysis and a similarity-percentage analysis. There were 16 all-turtle provinces, 15 freshwater provinces, and 13 aquatic provinces. Species compositions delineating the provinces were explained by abiotic variables, including mean annual precipitation, mean precipitation seasonality, and diversity of streams. Province delineations correspond closely with geographical boundaries, many of which have Pleistocene origins. For example, rivers with a history of carrying glacial runoff (e.g., Arkansas, Mississippi) sometimes dissect upland provinces, especially for aquatic and semiaquatic turtles. Compared with freshwater fishes, turtles show greater sensitivity to decreased temperature with restriction of most taxa south of the last permafrost maximum. Turtles also exhibit higher sensitivity to climatic, geomorphic, and tectonic instability, with richness and endemism concentrated along the more stable Gulf of México and Atlantic (south of the last permafrost maximum) coasts. Although distribution data indicate two aquatic turtles are most cold tolerant (i.e., Chrysemys picta, Chelydra serpentina), aquatic turtles overall show the most restriction to warmer, wetter climates. Sequential addition of semiaquatic and terrestrial turtles into analyses shows, as expected, that these taxa flesh out turtle faunas in climatically harsh (e.g., grasslands) or remote (e.g., California, Sonoran Desert) regions. The turtle assemblages of southwestern versus southeastern North America are distinct. But there is a transition zone across the semiarid plains of the Texas Gulf Coast, High Plains, and Chihuahuan Desert, including a strong boundary congruent with the Cochise Filter-Barrier. This is not a simple subdivision of Neotropical versus Nearctic taxa, as some lineages from both realms span the transition zone.

77 FR 39220 - Endangered Species; File No. 17183

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-02

... the research are to (1) obtain information on sea turtle ecology and health status; (2) determine the genetic origin of sea turtle populations in the region; (3) monitor turtle foraging habits; and (4...

The Box Turtle: Room with a View on Species Decline.

ERIC Educational Resources Information Center

Belzer, Bill; Steisslinger, Mary Beth

1999-01-01

Surveys salient aspects of eastern box-turtle natural history. Explores the societal and ecological factors that have contributed to the decline of the box-turtle population. Contains 18 references. (WRM)

Stable Isotopes of C and N Reveal Habitat Dependent Dietary Overlap between Native and Introduced Turtles Pseudemys rubriventris and Trachemys scripta

PubMed Central

Pearson, Steven H.; Avery, Harold W.; Kilham, Susan S.; Velinsky, David J.; Spotila, James R.

2013-01-01

Habitat degradation and species introductions are two of the leading causes of species declines on a global scale. Invasive species negatively impact native species through predation and competition for limited resources. The impacts of invasive species may be increased in habitats where habitat degradation is higher due to reductions of prey abundance and distribution. Using stable isotope analyses and extensive measurements of resource availability we determined how resource availability impacts the long term carbon and nitrogen assimilation of the invasive red-eared slider turtle (Trachemys scripta elegans) and a native, threatened species, the red-bellied turtle (Pseudemys rubriventris) at two different freshwater wetland complexes in Pennsylvania, USA. At a larger wetland complex with greater vegetative species richness and diversity, our stable isotope analyses showed dietary niche partitioning between species, whereas analyses from a smaller wetland complex with lower vegetative species richness and diversity showed significant dietary niche overlap. Determining the potential for competition between these two turtle species is important to understanding the ecological impacts of red-eared slider turtles in wetland habitats. In smaller wetlands with increased potential for competition between native turtles and invasive red-eared slider turtles we expect that when shared resources become limited, red-eared slider turtles will negatively impact native turtle species leading to long term population declines. Protection of intact wetland complexes and the reduction of introduced species populations are paramount to preserving populations of native species. PMID:23675437

Stable isotopes of C and N reveal habitat dependent dietary overlap between native and introduced turtles Pseudemys rubriventris and Trachemys scripta.

PubMed

Pearson, Steven H; Avery, Harold W; Kilham, Susan S; Velinsky, David J; Spotila, James R

2013-01-01

Habitat degradation and species introductions are two of the leading causes of species declines on a global scale. Invasive species negatively impact native species through predation and competition for limited resources. The impacts of invasive species may be increased in habitats where habitat degradation is higher due to reductions of prey abundance and distribution. Using stable isotope analyses and extensive measurements of resource availability we determined how resource availability impacts the long term carbon and nitrogen assimilation of the invasive red-eared slider turtle (Trachemys scripta elegans) and a native, threatened species, the red-bellied turtle (Pseudemys rubriventris) at two different freshwater wetland complexes in Pennsylvania, USA. At a larger wetland complex with greater vegetative species richness and diversity, our stable isotope analyses showed dietary niche partitioning between species, whereas analyses from a smaller wetland complex with lower vegetative species richness and diversity showed significant dietary niche overlap. Determining the potential for competition between these two turtle species is important to understanding the ecological impacts of red-eared slider turtles in wetland habitats. In smaller wetlands with increased potential for competition between native turtles and invasive red-eared slider turtles we expect that when shared resources become limited, red-eared slider turtles will negatively impact native turtle species leading to long term population declines. Protection of intact wetland complexes and the reduction of introduced species populations are paramount to preserving populations of native species.

Global distribution of Chelonid fibropapilloma-associated herpesvirus among clinically healthy sea turtles.

PubMed

Alfaro-Núñez, Alonzo; Frost Bertelsen, Mads; Bojesen, Anders Miki; Rasmussen, Isabel; Zepeda-Mendoza, Lisandra; Tange Olsen, Morten; Gilbert, Marcus Thomas Pius

2014-10-25

Fibropapillomatosis (FP) is a neoplastic disease characterized by cutaneous tumours that has been documented to infect all sea turtle species. Chelonid fibropapilloma-associated herpesvirus (CFPHV) is believed to be the aetiological agent of FP, based principally on consistent PCR-based detection of herpesvirus DNA sequences from FP tumours. We used a recently described PCR-based assay that targets 3 conserved CFPHV genes, to survey 208 green turtles (Chelonia mydas). This included both FP tumour exhibiting and clinically healthy individuals. An additional 129 globally distributed clinically healthy individual sea turtles; representing four other species were also screened. CFPHV DNA sequences were obtained from 37/37 (100%) FP exhibiting green turtles, and 45/300 (15%) clinically healthy animals spanning all five species. Although the frequency of infected individuals per turtle population varied considerably, most global populations contained at least one CFPHV positive individual, with the exception of various turtle species from the Arabian Gulf, Northern Indian Ocean and Puerto Rico. Haplotype analysis of the different gene markers clustered the CFPHV DNA sequences for two of the markers (UL18 and UL22) in turtles from Turks and Caicos separate to all others, regardless of host species or geographic origin. Presence of CFPHV DNA within globally distributed samples for all five species of sea turtle was confirmed. While 100% of the FP exhibiting green turtles yielded CFPHV sequences, surprisingly, so did 15% of the clinically healthy turtles. We hypothesize that turtle populations with zero (0%) CFPHV frequency may be attributed to possible environmental differences, diet and/or genetic resistance in these individuals. Our results provide first data on the prevalence of CFPHV among seemingly healthy turtles; a factor that may not be directly correlated to the disease incidence, but may suggest of a long-term co-evolutionary latent infection interaction between CFPHV and its turtle-host across species. Finally, computational analysis of amino acid variants within the Turks and Caicos samples suggest potential functional importance in a substitution for marker UL18 that encodes the major capsid protein gene, which potentially could explain differences in pathogenicity. Nevertheless, such a theory remains to be validated by further research.

Seasonal heterogeneity of ocean warming: a mortality sink for ectotherm colonizers

PubMed Central

Maffucci, Fulvio; Corrado, Raffaele; Palatella, Luigi; Borra, Marco; Marullo, Salvatore; Hochscheid, Sandra; Lacorata, Guglielmo; Iudicone, Daniele

2016-01-01

Distribution shifts are a common adaptive response of marine ectotherms to climate change but the pace of redistribution depends on species-specific traits that may promote or hamper expansion to northern habitats. Here we show that recently, the loggerhead turtle (Caretta caretta) has begun to nest steadily beyond the northern edge of the species’ range in the Mediterranean basin. This range expansion is associated with a significant warming of spring and summer sea surface temperature (SST) that offers a wider thermal window suitable for nesting. However, we found that post-hatchlings departing from this location experience low winter SST that may affect their survival and thus hamper the stabilization of the site by self-recruitment. The inspection of the Intergovernmental Panel on Climate Change model projections and observational data on SST trends shows that, despite the annual warming for this century, winter SST show little or no trends. Therefore, thermal constraints during the early developmental phase may limit the chance of population growth at this location also in the near future, despite increasingly favourable conditions at the nesting sites. Quantifying and understanding the interplay between dispersal and environmental changes at all life stages is critical for predicting ectotherm range expansion with climate warming. PMID:27044321

Status of a wood turtle (Glyptemys Insculpta) population in northeastern Minnesota

Treesearch

Madaline M. Cochrane; Donald J. Brown; Mark D. Nelson; Richard R. Buech; Mike Schrage; Dan Ryan; Ron A. Moen

2018-01-01

Wood Turtles (Glyptemys insculpta) have experienced population declines across their North American range and are state-listed as threatened in Minnesota, USA. To improve our understanding of the current conservation status of one population in northeastern Minnesota, we: (1) performed a snapshot comparison of population structure and relative...

Maternal investment in reproduction and its consequences in leatherback turtles.

PubMed

Wallace, Bryan P; Sotherland, Paul R; Tomillo, Pilar Santidrian; Reina, Richard D; Spotila, James R; Paladino, Frank V

2007-05-01

Maternal investment in reproduction by oviparous non-avian reptiles is usually limited to pre-ovipositional allocations to the number and size of eggs and clutches, thus making these species good subjects for testing hypotheses of reproductive optimality models. Because leatherback turtles (Dermochelys coriacea) stand out among oviparous amniotes by having the highest clutch frequency and producing the largest mass of eggs per reproductive season, we quantified maternal investment of 146 female leatherbacks over four nesting seasons (2001-2004) and found high inter- and intra-female variation in several reproductive characteristics. Estimated clutch frequency [coefficient of variation (CV) = 31%] and clutch size (CV = 26%) varied more among females than did egg mass (CV = 9%) and hatchling mass (CV = 7%). Moreover, clutch size had an approximately threefold higher effect on clutch mass than did egg mass. These results generally support predictions of reproductive optimality models in which species that lay several, large clutches per reproductive season should exhibit low variation in egg size and instead maximize egg number (clutch frequency and/or size). The number of hatchlings emerging per nest was positively correlated with clutch size, but fraction of eggs in a clutch yielding hatchlings (emergence success) was not correlated with clutch size and varied highly among females. In addition, seasonal fecundity and seasonal hatchling production increased with the frequency and the size of clutches (in order of effect size). Our results demonstrate that female leatherbacks exhibit high phenotypic variation in reproductive traits, possibly in response to environmental variability and/or resulting from genotypic variability within the population. Furthermore, high seasonal and lifetime fecundity of leatherbacks probably reflect compensation for high and unpredictable mortality during early life history stages in this species.

Observations of fibropapillomatosis in green turtles (Chelonia mydas) in Indonesia.

PubMed

Adnyana, W; Ladds, P W; Blair, D

1997-10-01

To determine the prevalence and manifestations of fibropapillomatosis in green turtles in Indonesia, to identify any relationship between fibropapillomatosis and concurrent parasitic infection, to ascertain the effect of fibropapillomatosis on health, and to examine whether environment might have an effect on the prevalence of fibropapillomatosis. 4407 green turtles (Chelonia mydas) and 401 hawksbill turtles (Eretmochelys imbricata) were examined. The occurrence of fibropapillomatosis was correlated with sex, maturity, curved carapace length, body weight/curved carapace length ratio, the number and distribution of tumours on the skin, parasite burdens, some haematological variables and the region of capture. Fibropapillomatosis was seen only in green turtles, and the overall prevalence in these was 21.5%. This prevalence increased with the curved carapace length up to 85 cm. The average number of tumours per affected turtle was 5 +/- SD 4.1 (range, 1 to 29), and was negatively correlated with the body weight/curved carapace length ratio (rs = -0.8; P = 0.001). The red blood cell count in turtles with fibropapilloma was lower than in non-fibropapilloma turtles captured and examined at the same time (P = 0.001). The prevalence of fibropapilloma in turtles captured near densely populated, industrial regions (26.3%) was greater than in turtles from sparsely populated areas (17.7%). Fibropapillomatosis in green sea turtles in Indonesia is of moderate occurrence: young mature turtles (curved carapace length = 85 cm) are most frequently affected. Fibropapilloma adversely affects health of turtles. Fluke infestation seems not to be a causal factor, but viral infection, perhaps with concurrent stress of environmental origin, seems likely.

77 FR 40895 - Culebra National Wildlife Refuge, PR; Draft Comprehensive Conservation Plan and Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-11

... Post at Punta Flamenco; (7) developing hiking trails; (8) completing boundary verification; and (9... of sea turtles and their nests/eggs. To benefit resident and migratory birds, annual surveys would be... management strategies to benefit target species of birds and cooperate with Puerto Rico DNER to conduct...

Monitoring functionality and durability of the New York State Highway 30 turtle barrier and adjacent nesting substrate.

DOT National Transportation Integrated Search

2012-08-01

In 2008, the NYS Department of Transportation installed a wildlife barrier along NYS Route 30 in Tupper Lake, Franklin County, NY. The major objectives of the study that is the subject of this report were to: evaluate the effectiveness of the Route 3...

Growth, population structure, and reproduction of western pond turtles (Actinemys marmorata) on the central coast of California

USGS Publications Warehouse

Germano, D.J.; Rathbun, G.B.

2008-01-01

We studied the population structure and growth of western pond turtles (Actinemys marmorata) at Vandenberg Air Force Base along the coast of central California in April 1995 and June 1996. We captured 179 individuals (115 males, 27 females) from 7 ponds during 26 days of trapping. Many turtles were adult-sized, but based on scute annuli, 74% were < 10 years of age, including many 2- to 3-year-olds. This population structure likely was due to a relatively fast growth rate, especially compared with closely related aquatic turtles in eastern North America. Mean clutch size was 5.2, but 66.7% of females were gravid, and 1 female produced 2 clutches. These reproductive data are similar to those reported for other populations in the southern portion of the species' range. Females reached reproductive maturity as early as 4 years of age. The relatively mild temperatures of California's Mediterranean climate, especially when compared to the seasonal extremes in more continental and northern regions of North America, may explain the different growth rates and population characteristics of freshwater turtles from these 2 regions of North America. ?? 2008 Chelonian Research Foundation.

Identifying Critical Habitat for Australian Freshwater Turtles in a Large Regulated Floodplain: Implications for Environmental Water Management

NASA Astrophysics Data System (ADS)

Ocock, J. F.; Bino, G.; Wassens, S.; Spencer, J.; Thomas, R. F.; Kingsford, R. T.

2018-03-01

Freshwater turtles face many threats, including habitat loss and river regulation reducing occupancy and contributing to population decline. Limited knowledge of hydrological conditions required to maintain viable turtle populations in large floodplain wetlands hinders effective adaptive management of environmental water in regulated rivers. We surveyed three turtle species over 4 years across the Lower Murrumbidgee River floodplain, a large wetland complex with a long history of water resource development. Using site and floodplain metrics and generalized linear models, within a Bayesian Model Averaging framework, we quantified the main drivers affecting turtle abundance. We also used a hierarchical modeling approach, requiring large sample sizes, quantifying possible environmental effects while accounting for detection probabilities of the eastern long-necked turtle ( Chelodina longicollis). The three species varied in their responses to hydrological conditions and connectivity to the main river channel. Broad-shelled turtles ( Chelodina expansa) and Macquarie River turtles ( Emydura macquarii macquarii) had restricted distributions, centered on frequently inundated wetlands close to the river, whereas the eastern long-necked turtles were more widely distributed, indicating an ability to exploit variable habitats. We conclude that turtle communities would benefit from long-term management strategies that maintain a spatiotemporal mosaic of hydrological conditions. More specifically, we identified characteristics of refuge habitats and stress the importance of maintaining their integrity during dry periods. Neighboring habitats can be targeted during increased water availability years to enhance feeding and dispersal opportunities for freshwater turtles.

The role of the integument as a barrier to penetration of ice into overwintering hatchlings of the painted turtle (Chrysemys picta).

PubMed

Willard, R; Packard, G C; Packard, M J; Tucker, J K

2000-11-01

Hatchlings of the North American painted turtle (Chrysemys picta) spend their first winter of life inside a shallow, subterranean hibernaculum (the natal nest) where they may be exposed for extended periods to ice and cold. Hatchlings seemingly survive exposure to such conditions by becoming supercooled (i.e., by remaining unfrozen at temperatures below the equilibrium freezing point for body fluids), so we investigated the role of their integument in preventing ice from penetrating into body compartments from surrounding soil. We first showed that hatchlings whose epidermis has been damaged are more likely to be penetrated by growing crystals of ice than are turtles whose cutaneous barrier is intact. We next studied integument from a forelimb by light microscopy and discovered that the basal part of the alpha-keratin layer of the epidermis contains a dense layer of lipid. Skin from the forelimb of other neonatal turtles lacks such a layer of lipid in the epidermis, and these other turtles also are highly susceptible to inoculative freezing. Moreover, epidermis from the neck of hatchling painted turtles lacks the lipid layer, and this region of the skin is readily penetrated by growing crystals of ice. We therefore conclude that the resistance to inoculation imposed by skin on the limbs of hatchling painted turtles results from the presence of lipids in the alpha-keratin layer of the epidermis. Neonates apparently are able to avoid freezing during winter by drawing much of the body inside the shell, leaving only the ice-resistant integument of the limbs exposed to ice in the environment. The combination of behavior and skin morphology enables overwintering hatchlings to exploit an adaptive strategy based on supercooling. Copyright 2000 Wiley-Liss, Inc.

The potential of unmanned aerial systems for sea turtle research and conservation: a review and future directions

USGS Publications Warehouse

Rees, Alan F.; Avens, Larisa; Ballorain, Katia; Bevan, Elizabeth; Broderick, Annette C.; Carthy, Raymond R.; Christianen, Marjolijn J. A.; Duclos, Gwénaël; Heithaus, Michael R.; Johnston, David W.; Mangel, Jeffrey C.; Paladino, Frank V.; Pendoley, Kellie; Reina, Richard D.; Robinson, Nathan J.; Ryan, Robert; Sykora-Bodie, Seth T.; Tilley, Dominic; Varela, Miguel R.; Whitman, Elizabeth R.; Whittock, Paul A.; Wibbels, Thane; Godley, Brendan J.

2018-01-01

The use of satellite systems and manned aircraft surveys for remote data collection has been shown to be transformative for sea turtle conservation and research by enabling the collection of data on turtles and their habitats over larger areas than can be achieved by surveys on foot or by boat. Unmanned aerial vehicles (UAVs) or drones are increasingly being adopted to gather data, at previously unprecedented spatial and temporal resolutions in diverse geographic locations. This easily accessible, low-cost tool is improving existing research methods and enabling novel approaches in marine turtle ecology and conservation. Here we review the diverse ways in which incorporating inexpensive UAVs may reduce costs and field time while improving safety and data quality and quantity over existing methods for studies on turtle nesting, at-sea distribution and behaviour surveys, as well as expanding into new avenues such as surveillance against illegal take. Furthermore, we highlight the impact that high-quality aerial imagery captured by UAVs can have for public outreach and engagement. This technology does not come without challenges. We discuss the potential constraints of these systems within the ethical and legal frameworks which researchers must operate and the difficulties that can result with regard to storage and analysis of large amounts of imagery. We then suggest areas where technological development could further expand the utility of UAVs as data-gathering tools; for example, functioning as downloading nodes for data collected by sensors placed on turtles. Development of methods for the use of UAVs in sea turtle research will serve as case studies for use with other marine and terrestrial taxa.

Telomeres, Age and Reproduction in a Long-Lived Reptile

PubMed Central

Plot, Virginie; Criscuolo, François; Zahn, Sandrine; Georges, Jean-Yves

2012-01-01

A major interest has recently emerged in understanding how telomere shortening, mechanism triggering cell senescence, is linked to organism ageing and life history traits in wild species. However, the links between telomere length and key history traits such as reproductive performances have received little attention and remain unclear to date. The leatherback turtle Dermochelys coriacea is a long-lived species showing rapid growth at early stages of life, one of the highest reproductive outputs observed in vertebrates and a dichotomised reproductive pattern related to migrations lasting 2 or 3 years, supposedly associated with different environmental conditions. Here we tested the prediction of blood telomere shortening with age in this species and investigated the relationship between blood telomere length and reproductive performances in leatherback turtles nesting in French Guiana. We found that blood telomere length did not differ between hatchlings and adults. The absence of blood telomere shortening with age may be related to an early high telomerase activity. This telomere-restoring enzyme was formerly suggested to be involved in preventing early telomere attrition in early fast-growing and long-lived species, including squamate reptiles. We found that within one nesting cycle, adult females having performed shorter migrations prior to the considered nesting season had shorter blood telomeres and lower reproductive output. We propose that shorter blood telomeres may result from higher oxidative stress in individuals breeding more frequently (i.e., higher costs of reproduction) and/or restoring more quickly their body reserves in cooler feeding areas during preceding migration (i.e., higher foraging costs). This first study on telomeres in the giant leatherback turtle suggests that blood telomere length predicts not only survival chances, but also reproductive performances. Telomeres may therefore be a promising new tool to evaluate individual reproductive quality which could be useful in such species of conservation concern. PMID:22808278

Understanding the biological invasion risk posed by the global wildlife trade: propagule pressure drives the introduction and establishment of Nearctic turtles.

PubMed

García-Díaz, Pablo; Ross, Joshua V; Ayres, César; Cassey, Phillip

2015-03-01

Biological invasions are a key component of human-induced global change. The continuing increase in global wildlife trade has raised concerns about the parallel increase in the number of new invasive species. However, the factors that link the wildlife trade to the biological invasion process are still poorly understood. Moreover, there are analytical challenges in researching the role of global wildlife trade in biological invasions, particularly issues related to the under-reporting of introduced and established populations in areas with reduced sampling effort. In this work, we use high-quality data on the international trade in Nearctic turtles (1999-2009) coupled with a statistical modelling framework, which explicitly accounts for detection, to investigate the factors that influence the introduction (release, or escape into the wild) of globally traded Nearctic turtles and the establishment success (self-sustaining exotic populations) of slider turtles (Trachemys scripta), the most frequently traded turtle species. We found that the introduction of a species was influenced by the total number of turtles exported to a jurisdiction and the age at maturity of the species, while the establishment success of slider turtles was best associated with the propagule number (number of release events), and the number of native turtles in the jurisdiction of introduction. These results indicate both a direct and indirect association between the wildlife trade and the introduction of turtles and establishment success of slider turtles, respectively. Our results highlight the existence of gaps in the number of globally recorded introduction events and established populations of slider turtles, although the expected bias is low. We emphasize the importance of researching independently the factors that affect the different stages of the invasion pathway. Critically, we observe that the number of traded individuals might not always be an adequate proxy for propagule pressure and establishment success. © 2014 John Wiley & Sons Ltd.

The diving behaviour of green turtles undertaking oceanic migration to and from Ascension Island: dive durations, dive profiles and depth distribution.

PubMed

Hays, G C; Akesson, S; Broderick, A C; Glen, F; Godley, B J; Luschi, P; Martin, C; Metcalfe, J D; Papi, F

2001-12-01

Satellite telemetry was used to record the submergence duration of green turtles (Chelonia mydas) as they migrated from Ascension Island to Brazil (N=12 individuals) while time/depth recorders (TDRs) were used to examine the depth distribution and dive profiles of individuals returning to Ascension Island to nest after experimental displacement (N=5 individuals). Satellite telemetry revealed that most submergences were short (<5 min) but that some submergences were longer (>20 min), particularly at night. TDRs revealed that much of the time was spent conducting short (2-4 min), shallow (approximately 0.9-1.5 m) dives, consistent with predictions for optimisation of near-surface travelling, while long (typically 20-30 min), deep (typically 10-20 m) dives had a distinctive profile found in other marine reptiles. These results suggest that green turtles crossing the Atlantic do not behave invariantly, but instead alternate between periods of travelling just beneath the surface and diving deeper. These deep dives may have evolved to reduce silhouetting against the surface, which would make turtles more susceptible to visual predators such as large sharks.

Digenetic trematode community in nesting green sea turtles (Chelonia mydas) from Tortuguero National Park, Costa Rica.

PubMed

Santoro, Mario; Greiner, Ellis C; Morales, Juan Alberto; Rodríguez-Ortíz, Beatriz

2006-12-01

The digenetic community of 40 green sea turtles (Chelonia mydas) was investigated at Tortuguero National Park, Costa Rica. In total, 24,270 trematodes belonging to 29 species and 6 families including Clinostomidae 1, Microscaphidiidae 5, Paramphistomidae 2, Pronocephalidae 15, Rhytidodidae 2, and Spirorchiidae 4 were recorded from chelonians examined. Turtles harbored a mean of 7.63 +/- 3.5 SD species. Only 3 species, i.e., Learedius learedi, Microscaphidium reticulare, and Pyelosomum cochlear, infected more than 50% of the hosts sampled. Learedius learedi was the most prevalent (97.5%) and the second most abundant species with a mean of 25.6 +/- 21.6 SD. Only 1 core species, M. reticulare, was recovered from the gastrointestinal tract; it was the most abundant parasite, with a mean intensity of 477 +/- 1,180 SD, and the second most prevalent (77.5%). Diversity values ranged from 0.10 to 2.10, with a mean of 1.00 +/- 0.43 SD for the total component community and from 0.10 to 1.84, with a mean of 0.79 +/- 0.41 SD, for the gastrointestinal component community. Species richness was the highest recorded from a sea turtle species. All digenetic species were recorded from Costa Rica for the first time. This represents the first report on the helminth community of the green turtle.

Chemical contamination of green turtle (Chelonia mydas) eggs in peninsular Malaysia: implications for conservation and public health.

PubMed

van de Merwe, Jason P; Hodge, Mary; Olszowy, Henry A; Whittier, Joan M; Ibrahim, Kamarruddin; Lee, Shing Y

2009-09-01

Persistent organic pollutants (POPs)-such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs)-and heavy metals have been reported in sea turtles at various stages of their life cycle. These chemicals can disrupt development and function of wildlife. Furthermore, in areas such as Peninsular Malaysia, where the human consumption of sea turtle eggs is prevalent, egg contamination may also have public health implications. In the present study we investigated conservation and human health risks associated with the chemical contamination of green turtle (Chelonia mydas) eggs in Peninsular Malaysia. Fifty-five C. mydas eggs were collected from markets in Peninsular Malaysia and analyzed for POPs and heavy metals. We conducted screening risk assessments (SRAs) and calculated the percent of acceptable daily intake (ADI) for POPs and metals to assess conservation and human health risks associated with egg contamination. C. mydas eggs were available in 9 of the 33 markets visited. These eggs came from seven nesting areas from as far away as Borneo Malaysia. SRAs indicated a significant risk to embryonic development associated with the observed arsenic concentrations. Furthermore, the concentrations of coplanar PCBs represented 3 300 times the ADI values set by the World Health Organization. The concentrations of POPs and heavy metals reported in C. mydas eggs from markets in Peninsular Malaysia pose considerable risks to sea turtle conservation and human health.

Assessment of exposure to lead in humans and turtles living in an industrial site in Coatzacoalcos Veracruz, Mexico.

PubMed

Pelallo-Martínez, N A; Ilizaliturri-Hernández, C A; Espinosa-Reyes, G; Carrizales-Yáñez, L; González-Mille, D J

2011-06-01

The intake of lead from the environment may occur thru various receptors. In order to measure lead levels absorbed, samples were taken from Children who live in three localities surrounding an industrial complex in Coatzacoalcos, Veracruz. Samples were also taken from turtles. Samples were analyzed and results were compared against the general population. In children tested, over 75% of all values were determined to be above CDC's safety levels of (10 μg/dL). The geometric mean lead concentration was 11.4 μg/dL, which is clearly higher around the industrial complex than in the general population. In turtles, lead blood levels in the exposed population were 2-fold above (24.2 μg/dL) those of turtles in the reference population (10.1 μg/dL). Lead levels observed represent a risk for both human and fauna health.

Survey and analysis design for wood turtle population monitoring

Treesearch

Donald J. Brown; Madaline M. Cochrane; Ron A. Moen

2017-01-01

Population monitoring is a fundamental component of wildlife management, and is necessary to track site- and regional-level status and recovery of species of conservation concern. The wood turtle (Glyptemys insculpta) is a species of conservation concern for federal and state agencies because of population declines across the species' range....

Diagnosis and management of oviductal disease in three red-eared slider turtles (Trachemys scripta elegans).

PubMed

Mans, C; Sladky, K K

2012-04-01

Three mature, female, red-eared slider turtles (Trachemys scripta elegans) were individually, and separately, diagnosed with different forms of oviductal disease. Case 1 presented with acute cloacal bleeding and was diagnosed with acute oviductal rupture and ectopic eggs in the coelom. Case 2 presented for repeated scratching in the direction of the cloaca and was diagnosed with chronic oviductal impaction and coelomitis. Both cases were treated successfully by endoscopy-assisted complete ovariosalpingectomy via a bilateral prefemoral approach. Case 3 presented with a reduced appetite and signs of nesting behaviour and was diagnosed with obstructive dystocia associated with bacterial salpingitis. Successful treatment consisted of transcloacal egg removal and systemic antibiotics. Complete recovery was achieved in all three turtles, which remained disease-free 23 to 33 months later. Oviductal disease can present with a variety of clinical signs, and an accurate diagnosis can be made based on a thorough history, physical examination and appropriate diagnostic techniques. © 2012 British Small Animal Veterinary Association.

Chlorinated hydrocarbons in early life stages of the common snapping turtle (Chelydra serpentina serpentina) from a coastal wetland on Lake Ontario, Canada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bishop, C.A.; Lean, D.R.S.; Carey, J.H.

1995-03-01

To assess intra-clutch variation in contaminant concentrations in eggs, and to investigate the dynamics of chlorinated hydrocarbon accumulation in embryos of the common snapping turtle (Chelydra serpentina), concentrations of p,p{prime}-DDE, hexachlorobenzene, trans-nonachlor, cis-chlordane, and six PCB congeners were measured in eggs, embryos, and hatchlings. Samples were collected from Cootes Paradise, a wetland at the western end of Lake Ontario, Ontario, Canada. The intra-clutch variation in chlorinated hydrocarbon concentrations within four snapping turtle clutches was determined by analyzing the first, last, and middle five eggs oviposited in the nest. The first five eggs had the highest mean concentrations of all chlorinatedmore » hydrocarbons, wet weight, and egg diameter. On a lipid weight basis, the first five eggs contained the highest concentration of all compounds except total PCBs and cis-chlordane. The concentration of cis-chlordane was the only parameter measured that was significantly different among the three sets of eggs. At hatching, snapping turtles without yolk sacs contained from 55.2 to 90.5% of the absolute amount of organochlorine compounds measured in the egg at oviposition. Eighteen days after hatching, the body burden of PCBs and pesticides decreased to 45.3 to 62.2% of that in the fresh egg. The accumulation of organochlorine chemicals in embryonic turtles peaked at or just before hatching and then declined thereafter, which is consistent with trends reported in developing sea turtles, fish, and birds.« less

Hatchling turtles survive freezing during winter hibernation.

PubMed Central

Storey, K B; Storey, J M; Brooks, S P; Churchill, T A; Brooks, R J

1988-01-01

Hatchlings of the painted turtle (Chrysemys picta marginata) are unique as the only reptile and highest vertebrate life form known to tolerate the natural freezing of extracellular body fluids during winter hibernation. Turtles survived frequent exposures to temperatures as low as -6 degrees C to -8 degrees C in their shallow terrestrial nests over the 1987-1988 winter. Hatchlings collected in April 1988 had a mean supercooling point of -3.28 +/- 0.24 degrees C and survived 24 hr of freezing at -4 degrees C with 53.4% +/- 1.98% of total body water as ice. Recovery appeared complete after 20 hr of thawing at 3 degrees C. However, freezing at -10.9 degrees C, resulting in 67% ice, was lethal. A survey of possible cryoprotectants revealed a 2- to 3-fold increase in glucose content of liver and blood and a 3-fold increase in blood glycerol in response to freezing. Although quantitatively low, these responses by spring turtles strongly indicate that these may be the winter-active cryoprotectants. The total amino acid pool of blood also increased 2.25-fold in freezing-exposed turtles, and taurine accounted for 52% of the increase. Most organs accumulated high concentrations of lactate during freezing, a response to the ischemic state imposed by extracellular freezing. Changes in glycogen phosphorylase activity and levels of glucose 6-phosphate and fructose 2,6-bisphosphate were also consistent with a dependence on anaerobic glycolysis during freezing. Studies of the molecular mechanisms of natural freeze tolerance in these turtles may identify protective strategies that can be used in mammalian organ cryopreservation technology. PMID:3186730

Behaviour and buoyancy regulation in the deepest-diving reptile: the leatherback turtle.

PubMed

Fossette, Sabrina; Gleiss, Adrian C; Myers, Andy E; Garner, Steve; Liebsch, Nikolai; Whitney, Nicholas M; Hays, Graeme C; Wilson, Rory P; Lutcavage, Molly E

2010-12-01

In the face of the physical and physiological challenges of performing breath-hold deep dives, marine vertebrates have evolved different strategies. Although behavioural strategies in marine mammals and seabirds have been investigated in detail, little is known about the deepest-diving reptile - the leatherback turtle (Dermochelys coriacea). Here, we deployed tri-axial accelerometers on female leatherbacks nesting on St Croix, US Virgin Islands, to explore their diving strategy. Our results show a consistent behavioural pattern within dives among individuals, with an initial period of active swimming at relatively steep descent angles (∼-40 deg), with a stroke frequency of 0.32 Hz, followed by a gliding phase. The depth at which the gliding phase began increased with the maximum depth of the dives. In addition, descent body angles and vertical velocities were higher during deeper dives. Leatherbacks might thus regulate their inspired air-volume according to the intended dive depth, similar to hard-shelled turtles and penguins. During the ascent, turtles actively swam with a stroke frequency of 0.30 Hz but with a low vertical velocity (∼0.40 ms(-1)) and a low pitch angle (∼+26 deg). Turtles might avoid succumbing to decompression sickness ('the bends') by ascending slowly to the surface. In addition, we suggest that the low body temperature of this marine ectotherm compared with that of endotherms might help reduce the risk of bubble formation by increasing the solubility of nitrogen in the blood. This physiological advantage, coupled with several behavioural and physical adaptations, might explain the particular ecological niche the leatherback turtle occupies among marine reptiles.

First record of hybridization between green Chelonia mydas and hawksbill Eretmochelys imbricata sea turtles in the Southeast Pacific.

PubMed

Kelez, Shaleyla; Velez-Zuazo, Ximena; Pacheco, Aldo S

2016-01-01

Hybridization among sea turtle species has been widely reported in the Atlantic Ocean, but their detection in the Pacific Ocean is limited to just two individual hybrid turtles, in the northern hemisphere. Herein, we report, for the first time in the southeast Pacific, the presence of a sea turtle hybrid between the green turtle Chelonia mydas and the hawksbill turtle Eretmochelys imbricata. This juvenile sea turtle was captured in northern Peru (4°13'S; 81°10'W) on the 5(th) of January, 2014. The individual exhibited morphological characteristics of C. mydas such as dark green coloration, single pair of pre-frontal scales, four post-orbital scales, and mandibular median ridge, while the presence of two claws in each frontal flipper, and elongated snout resembled the features of E. imbricata. In addition to morphological evidence, we confirmed the hybrid status of this animal using genetic analysis of the mitochondrial gene cytochrome oxidase I, which revealed that the hybrid individual resulted from the cross between a female E. imbricata and a male C. mydas. Our report extends the geographical range of occurrence of hybrid sea turtles in the Pacific Ocean, and is a significant observation of interspecific breeding between one of the world's most critically endangered populations of sea turtles, the east Pacific E. imbricata, and a relatively healthy population, the east Pacific C. mydas.

Phenological response of sea turtles to environmental variation across a species' northern range.

PubMed

Mazaris, Antonios D; Kallimanis, Athanasios S; Pantis, John D; Hays, Graeme C

2013-01-22

Variations in environmental parameters (e.g. temperature) that form part of global climate change have been associated with shifts in the timing of seasonal events for a broad range of organisms. Most studies evaluating such phenological shifts of individual taxa have focused on a limited number of locations, making it difficult to assess how such shifts vary regionally across a species range. Here, by using 1445 records of the date of first nesting for loggerhead sea turtles (Caretta caretta) at different breeding sites, on different continents and in different years across a broad latitudinal range (25-39° 'N), we demonstrate that the gradient of the relationship between temperature and the date of first breeding is steeper at higher latitudes, i.e. the phenological responses to temperature appear strongest at the poleward range limit. These findings support the hypothesis that biological changes in response to climate change will be most acute at the poleward range limits and are in accordance with the predictions of MacArthur's hypothesis that poleward range limit for species range is environmentally limited. Our findings imply that the poleward populations of loggerheads are more sensitive to climate variations and thus they might display the impacts of climate change sooner and more prominently.

Phenological response of sea turtles to environmental variation across a species' northern range

PubMed Central

Mazaris, Antonios D.; Kallimanis, Athanasios S.; Pantis, John D.; Hays, Graeme C.

2013-01-01

Variations in environmental parameters (e.g. temperature) that form part of global climate change have been associated with shifts in the timing of seasonal events for a broad range of organisms. Most studies evaluating such phenological shifts of individual taxa have focused on a limited number of locations, making it difficult to assess how such shifts vary regionally across a species range. Here, by using 1445 records of the date of first nesting for loggerhead sea turtles (Caretta caretta) at different breeding sites, on different continents and in different years across a broad latitudinal range (25–39° ′N), we demonstrate that the gradient of the relationship between temperature and the date of first breeding is steeper at higher latitudes, i.e. the phenological responses to temperature appear strongest at the poleward range limit. These findings support the hypothesis that biological changes in response to climate change will be most acute at the poleward range limits and are in accordance with the predictions of MacArthur's hypothesis that poleward range limit for species range is environmentally limited. Our findings imply that the poleward populations of loggerheads are more sensitive to climate variations and thus they might display the impacts of climate change sooner and more prominently. PMID:23193130

Removal of nonnative slider turtles (Trachemys scripta) and effects on native Sonora mud turtles (Kinosternon sonoriense) at Montezuma Well, Yavapai County, Arizona

USGS Publications Warehouse

Drost, Charles A.; Lovich, Jeffrey E.; Madrak, Sheila V.; Monatesti, A.J.

2011-01-01

The National Park Service (NPS) estimates that 234 national parks contain nonnative, invasive animal species that are of management concern (National Park Service, 2004). Understanding and controlling invasive species is thus an important priority within the NPS (National Park Service, 1996). The slider turtle (Trachemys scripta) is one such invasive species. Native to the Southeastern United States (Ernst and Lovich, 2009), as well as Mexico, Central America, and portions of South America (Ernst and Barbour, 1989), the slider turtle has become established throughout the continental United States and in other locations around the world (Burke and others, 2000). Slider turtle introductions have been suspected to be a threat to native turtles (Holland 1994; da Silva and Blasco, 1995), however, there has not been serious study of their effects until recently. Cadi and Joly (2003) found that slider turtles outcompeted European pond turtles (Emys orbicularis) for preferred basking sites under controlled experimental conditions, demonstrating for the first time direct competition for resources between a native and an exotic turtle species. Similarly, Spinks and others (2003) suggested that competition for basking sites between slider turtles and Pacific pond turtles (Actinemys marmorata) was partly responsible for the decline of Pacific pond turtles observed at their study site in California. They concluded that the impact of introduced slider turtles was 'almost certainly negative' for the western pond turtle. In the most recent critical study to assess the effects of introduced slider turtles on native turtles, Cadi and Joly (2004) demonstrated that European pond turtles that were kept under experimentally controlled conditions with slider turtles lost body weight and exhibited higher rates of mortality than in control groups of turtles comprised of the same species, demonstrating potential population-level effects on native species. Slider turtles are not native to Arizona but have been introduced in several areas in the southern and central part of the State, including Montezuma Well (the Well). The only native turtle at the Well is the Sonora mud turtle (Kinosternon sonoriense). Interactions between sliders and mud turtles have not been investigated at the Well or elsewhere. However, basking sites preferred by aquatic turtles are rare at the Well, suggesting one potential avenue for resource competition between sliders and Sonora mud turtles. In this study, we collected data on both species to evaluate the possible effects of slider turtles on Sonora mud turtles at Montezuma Well. During live trapping in the spring, summer, and early fall of 2007 and 2008, we removed slider turtles that we captured in the Well. We also collected ecological data on the mud turtles captured in the trapping effort. Separate behavioral observations of the turtles in the Well provided additional information on the ecology of the two species in the unusual environment of the Well, and also of interactions between the sliders and mud turtles. In this report, we describe the results of 2 yr of study of the turtles of Montezuma Well. We incorporate older data on the mud turtles in the Well to assess long-term population trends and potential response to the introduced slider turtles. We also report on aspects of basic ecology for the poorly understood Sonora mud turtle. The National Park Service requested that we incorporate public outreach as part of this research effort, so we also describe the outreach efforts associated with the turtle study.

Evidence of counter-gradient growth in western pond turtles (Actinemys marmorata) across thermal gradients

USGS Publications Warehouse

Snover, Melissa; Adams, Michael J.; Ashton, Donald T.; Bettaso, Jamie B.; Welsh, Hartwell H.

2015-01-01

Given the importance of size and age at reproductive maturity to population dynamics, this information on counter-gradient growth will improve our ability to understand and predict the consequences of dam operations for downstream turtle populations.

Common coastal foraging areas for loggerheads in the Gulf of Mexico: Opportunities for marine conservation

USGS Publications Warehouse

Hart, Kristen M.; Lamont, Margaret M.; Fujisaki, Ikuko; Tucker, Anton D.; Carthy, Raymond R.

2012-01-01

Designing conservation strategies that protect wide-ranging marine species is a significant challenge, but integrating regional telemetry datasets and synthesizing modeled movements and behavior offer promise for uncovering distinct at-sea areas that are important habitats for imperiled marine species. Movement paths of 10 satellite-tracked female loggerheads (Caretta caretta) from three separate subpopulations in the Gulf of Mexico, USA, revealed migration to discrete foraging sites in two common areas at-sea in 2008, 2009, and 2010. Foraging sites were 102–904 km away from nesting and tagging sites, and located off southwest Florida and the northern Yucatan Peninsula, Mexico. Within 3–35 days, turtles migrated to foraging sites where they all displayed high site fidelity over time. Core-use foraging areas were 13.0–335.2 km2 in size, in water <50 m deep, within a mean distance to nearest coastline of 58.5 km, and in areas of relatively high net primary productivity. The existence of shared regional foraging sites highlights an opportunity for marine conservation strategies to protect important at-sea habitats for these imperiled marine turtles, in both USA and international waters. Until now, knowledge of important at-sea foraging areas for adult loggerheads in the Gulf of Mexico has been limited. To better understand the spatial distribution of marine turtles that have complex life-histories, we propose further integration of disparate tracking data-sets at the oceanic scale along with modeling of movements to identify critical at-sea foraging habitats where individuals may be resident during non-nesting periods.

Sensory signals and neuronal groups involved in guiding the sea-ward motor behavior in turtle hatchlings of Chelonia agassizi

NASA Astrophysics Data System (ADS)

Fuentes, A. L.; Camarena, V.; Ochoa, G.; Urrutia, J.; Gutierrez, G.

2007-05-01

Turtle hatchlings orient display sea-ward oriented movements as soon as they emerge from the nest. Although most studies have emphasized the role of the visual information in this process, less attention has been paid to other sensory modalities. Here, we evaluated the nature of sensory cues used by turtle hatchlings of Chelonia agassizi to orient their movements towards the ocean. We recorded the time they took to crawl from the nest to the beach front (120m long) in control conditions and in visually, olfactory and magnetically deprived circumstances. Visually-deprived hatchlings displayed a high degree of disorientation. Olfactory deprivation and magnetic field distortion impaired, but not abolished, sea-ward oriented movements. With regard to the neuronal mapping experiments, visual deprivation reduced dramatically c-fos expression in the whole brain. Hatchlings with their nares blocked revealed neurons with c-fos expression above control levels principally in the c and d areas, while those subjected to magnetic field distortion had a wide spread activation of neurons throughout the brain predominantly in the dorsal ventricular ridge The present results support that Chelonia agassizi hatchlings use predominantly visual cues to orient their movements towards the sea. Olfactory and magnetic cues may also be use but their influence on hatchlings oriented motor behavior is not as clear as it is for vision. This conclusion is supported by the fact that in the absence of olfactory and magnetic cues, the brain turns on the expression of c- fos in neuronal groups that, in the intact hatchling, are not normally involved in accomplishing the task.