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Sample records for adult fish populations

  1. Geographic coupling of juvenile and adult habitat shapes spatial population dynamics of a coral reef fish.

    PubMed

    Huijbers, Chantal M; Nagelkerken, Ivan; Debrot, Adolphe O; Jongejans, Eelke

    2013-08-01

    Marine spatial population dynamics are often addressed with a focus on larval dispersal, without taking into account movement behavior of individuals in later life stages. Processes occurring during demersal life stages may also drive spatial population dynamics if habitat quality is perceived differently by animals belonging to different life stages. In this study, we used a dual approach to understand how stage-structured habitat use and dispersal ability of adults shape the population of a marine fish species. Our study area and focal species provided us with the unique opportunity to study a closed island population. A spatial simulation model was used to estimate dispersal distances along a coral reef that surrounds the island, while contributions of different nursery bays were determined based on otolith stable isotope signatures of adult reef fish. The model showed that adult dispersal away from reef areas near nursery bays is limited. The results further show that different bays contributed unequally to the adult population on the coral reef, with productivity of juveniles in bay nursery habitat determining the degree of mixing among local populations on the reef and with one highly productive area contributing most to the island's reef fish population. The contribution of the coral reef as a nursery habitat was minimal, even though it had a much larger surface area. These findings indicate that the geographic distribution of nursery areas and their productivity are important drivers for the spatial distribution patterns of adults on coral reefs. We suggest that limited dispersal of adults on reefs can lead to a source-sink structure in the adult stage, where reefs close to nurseries replenish more isolated reef areas. Understanding these spatial population dynamics of the demersal phase of marine animals is of major importance for the design and placement of marine reserves, as nursery areas contribute differently to maintain adult populations.

  2. Fishing amplifies forage fish population collapses.

    PubMed

    Essington, Timothy E; Moriarty, Pamela E; Froehlich, Halley E; Hodgson, Emma E; Koehn, Laura E; Oken, Kiva L; Siple, Margaret C; Stawitz, Christine C

    2015-05-26

    Forage fish support the largest fisheries in the world but also play key roles in marine food webs by transferring energy from plankton to upper trophic-level predators, such as large fish, seabirds, and marine mammals. Fishing can, thereby, have far reaching consequences on marine food webs unless safeguards are in place to avoid depleting forage fish to dangerously low levels, where dependent predators are most vulnerable. However, disentangling the contributions of fishing vs. natural processes on population dynamics has been difficult because of the sensitivity of these stocks to environmental conditions. Here, we overcome this difficulty by collating population time series for forage fish populations that account for nearly two-thirds of global catch of forage fish to identify the fingerprint of fisheries on their population dynamics. Forage fish population collapses shared a set of common and unique characteristics: high fishing pressure for several years before collapse, a sharp drop in natural population productivity, and a lagged response to reduce fishing pressure. Lagged response to natural productivity declines can sharply amplify the magnitude of naturally occurring population fluctuations. Finally, we show that the magnitude and frequency of collapses are greater than expected from natural productivity characteristics and therefore, likely attributed to fishing. The durations of collapses, however, were not different from those expected based on natural productivity shifts. A risk-based management scheme that reduces fishing when populations become scarce would protect forage fish and their predators from collapse with little effect on long-term average catches.

  3. Fluctuations of fish populations and the magnifying effects of fishing.

    PubMed

    Shelton, Andrew O; Mangel, Marc

    2011-04-26

    A central and classic question in ecology is what causes populations to fluctuate in abundance. Understanding the interaction between natural drivers of fluctuating populations and human exploitation is an issue of paramount importance for conservation and natural resource management. Three main hypotheses have been proposed to explain fluctuations: (i) species interactions, such as predator-prey interactions, cause fluctuations, (ii) strongly nonlinear single-species dynamics cause fluctuations, and (iii) environmental variation cause fluctuations. We combine a general fisheries model with data from a global sample of fish species to assess how two of these hypothesis, nonlinear single-species dynamics and environmental variation, interact with human exploitation to affect the variability of fish populations. In contrast with recent analyses that suggest fishing drives increased fluctuations by changing intrinsic nonlinear dynamics, we show that single-species nonlinear dynamics alone, both in the presence and absence of fisheries, are unlikely to drive deterministic fluctuations in fish; nearly all fish populations fall into regions of stable dynamics. However, adding environmental variation dramatically alters the consequences of exploitation on the temporal variability of populations. In a variable environment, (i) the addition of mortality from fishing leads to increased temporal variability for all species examined, (ii) variability in recruitment rates of juveniles contributes substantially more to fluctuations than variation in adult mortality, and (iii) the correlation structure of juvenile and adult vital rates plays an important and underappreciated role in determining population fluctuations. Our results are robust to alternative model formulations and to a range of environmental autocorrelation.

  4. Stage-specific biomass overcompensation by juveniles in response to increased adult mortality in a wild fish population.

    PubMed

    Ohlberger, Jan; Langangen, Øystein; Edeline, Eric; Claessen, David; Winfield, Ian J; Stenseth, Nils Chr; Vøllestad, L Asbjørn

    2011-12-01

    Recently developed theoretical models of stage-structured consumer-resource systems have shown that stage-specific biomass overcompensation can arise in response to increased mortality rates. We parameterized a stage-structured population model to simulate the effects of increased adult mortality caused by a pathogen outbreak in the perch (Perca fluviatilis) population of Windermere (UK) in 1976. The model predicts biomass overcompensation by juveniles in response to increased adult mortality due to a shift in food-dependent growth and reproduction rates. Considering cannibalism between life stages in the model reinforces this compensatory response due to the release from predation on juveniles at high mortality rates. These model predictions are matched by our analysis of a 60-year time series of scientific monitoring of Windermere perch, which shows that the pathogen outbreak induced a strong decrease in adult biomass and a corresponding increase in juvenile biomass. Age-specific adult fecundity and size at age were higher after than before the disease outbreak, suggesting that the pathogen-induced mortality released adult perch from competition, thereby increasing somatic and reproductive growth. Higher juvenile survival after the pathogen outbreak due to a release from cannibalism likely contributed to the observed biomass overcompensation. Our findings have general implications for predicting population- and community-level responses to increased size-selective mortality caused by exploitation or disease outbreaks.

  5. Dietary exposure to perfluoroalkyl acids of specific French adult sub-populations: high seafood consumers, high freshwater fish consumers and pregnant women.

    PubMed

    Yamada, A; Bemrah, N; Veyrand, B; Pollono, C; Merlo, M; Desvignes, V; Sirot, V; Marchand, P; Berrebi, A; Cariou, R; Antignac, J P; Le Bizec, B; Leblanc, J C

    2014-09-01

    Perfluoroalkyl acids (PFAAs) are globally found in various media, including food and especially fishery products. In the present study, the dietary exposure to 15 perfluoroalkyl acids was assessed for 3 French adult populations, namely high seafood consumers, high freshwater fish consumers, and pregnant women. Purified food extracts were analysed by LC-MS/MS and PFBA, PFPA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnA, PFTrDA, PFTeDA, PFBS, PFHxS, PFHpS, PFOS and PFDS were monitored and quantified according to the isotope dilution principle. Under lower bound (LB) hypothesis (i.e. contamination valuesfish consumers appear as the most exposed to PFOS (7.5 ng.kg(-1) bw.d(-1)), PFUnA (1.3 ng.kg(-1) bw.d(-1)), PFDA (0.4 ng.kg(-1) bw.d(-1)) and PFHpS (0.03 ng.kg(-1) bw.d(-1)) while high seafood consumers appear as the most exposed to PFOA (1.2 ng.kg(-1) bw.d(-1)), PFNA (0.2 ng.kg(-1) bw.d(-1)) and PFHxS (0.06 ng.kg(-1) bw.d(-1)). For all considered populations, the major exposure contributors are fish, seafood and water under LB hypothesis, while dairy products, bread and crispbread are the main contributors under upper bound (UB) hypothesis. Besides this food exposure assessment, further studies are needed to assess the more global PFAA exposure, taking into account indoor and outdoor air, dust and cutaneous contact, which could be other important contributors for this particular class of chemicals.

  6. Fish populations surviving estrogen pollution.

    PubMed

    Wedekind, Claus

    2014-02-10

    Among the most common pollutants that enter the environment after passing municipal wastewater treatment are estrogens, especially the synthetic 17α-ethinylestradiol that is used in oral contraceptives. Estrogens are potent endocrine disruptors at concentrations frequently observed in surface waters. However, new genetic analyses suggest that some fish populations can be self-sustaining even in heavily polluted waters. We now need to understand the basis of this tolerance.

  7. Fish populations surviving estrogen pollution

    PubMed Central

    2014-01-01

    Among the most common pollutants that enter the environment after passing municipal wastewater treatment are estrogens, especially the synthetic 17α-ethinylestradiol that is used in oral contraceptives. Estrogens are potent endocrine disruptors at concentrations frequently observed in surface waters. However, new genetic analyses suggest that some fish populations can be self-sustaining even in heavily polluted waters. We now need to understand the basis of this tolerance. See research article: http://www.biomedcentral.com/1741-7007/12/1 PMID:24512617

  8. Diagnosis of adults Xp11.2 translocation renal cell carcinoma by immunohistochemistry and FISH assays: clinicopathological data from ethnic Chinese population

    PubMed Central

    Qu, Yuanyuan; Gu, Chengyuan; Wang, Hongkai; Chang, Kun; Yang, Xiaoqun; Zhou, Xiaoyan; Dai, Bo; Zhu, Yao; Shi, Guohai; Zhang, Hailiang; Ye, Dingwei

    2016-01-01

    This study aimed to assess the utility of transcription factor E3 (TFE3) break-apart fluorescence in situ hybridization (FISH) assay in diagnosis of Xp11.2 translocation renal cell carcinoma (Xp11.2 RCC) and to compare the clinicopathological features between adult Xp11.2 RCC and non-Xp11.2 RCC. 76 pathologically suspected Xp11.2 RCCs were recruited from our institution. Both TFE3 immunohistochemistry (IHC) and TFE3 FISH assay were performed for the entire cohort. The progression-free survival (PFS) and overall survival (OS) curves were estimated using the Kaplan-Meier method. FISH analysis confirmed 30 Xp11.2 RCCs, including 28 cases with positive TFE3 immunostaining and 2 cases with negative immunostaining. The false-positive and false-negative rates were 6.7% (2/30) and 4.3% (2/46), respectively, for TFE3 IHC compared with FISH assay. Xp11.2 RCC was significantly associated with higher pathological stage and Fuhrman nuclear grade compared with non-Xp11.2 RCC (P < 0.05). The median PFS and OS for TFE3 FISH-positive group were 13.0 months (95% CI, 8.4–17.6 months) and 50.0 months (95% CI, 27.6–72.4 months), respectively, while the median PFS and OS had not been reached for TFE3 FISH-negative group. In conclusion, TFE3 break-apart FISH assay is a highly useful and standard diagnostic method for Xp11.2 RCC. Adult Xp11.2 RCC is clinically aggressive and often presents at advanced stage with poor prognosis. PMID:26880493

  9. Genomic Approaches with Natural Fish Populations

    PubMed Central

    Oleksiak, M. F.

    2011-01-01

    Natural populations versus inbred stocks provide a much richer resource for identifying the effects of nucleotide substitutions because natural populations have greater polymorphism. Additionally, natural populations offer an advantage over most common research organisms because they are subject to natural selection, and analyses of these adaptations can be used to identify biologically important changes. Among fishes, these analyses are enhanced by having a wide diversity of species (> 28,000 species, more than any other group of vertebrates) living in a huge range of environments (from below freezing to > 46° C, in fresh water to salinities > 40 ppt.). Moreover, fishes exhibit many different life history and reproductive strategies and have many different phenotypes and social structures. While fishes provide numerous advantages over other vertebrate models, there is still a dearth of available genomic tools for fishes. Fish make up approximately half of all known vertebrate species, yet less than 0.2% of fish species have significant genomic resources. Nonetheless, genomic approaches with fishes have provided some of the first measures of individual variation in gene expression and insights in to environmental and ecological adaptations. Thus, genomic approaches with natural fish populations have the potential to revolutionize fundamental studies of diverse fish species that offer myriad ecological and evolutionary questions. PMID:20409163

  10. Vibrio diseases of marine fish populations

    NASA Astrophysics Data System (ADS)

    Colwell, R. R.; Grimes, D. J.

    1984-03-01

    Several Vibrio spp. cause disease in marine fish populations, both wild and cultured. The most common disease, vibriosis, is caused by V. anguillarum. However, increase in the intensity of mariculture, combined with continuing improvements in bacterial systematics, expands the list of Vibrio spp. that cause fish disease. The bacterial pathogens, species of fish affected, virulence mechanisms, and disease treatment and prevention are included as topics of emphasis in this review.

  11. POPULATION DECLINE IN STREAM FISH

    EPA Science Inventory

    Over half of the streams in the Mid-Atlantic Highlands have fish communities that are in fair or poor condition, and the EPA concluded that physical habitat alteration represents the greatest potential stressor across this region. A quantitative method for relating habitat quali...

  12. Social recognition in wild fish populations

    PubMed Central

    Ward, Ashley J.W; Webster, Michael M; Hart, Paul J.B

    2007-01-01

    The ability of animals to gather information about their social and physical environment is essential for their ecological function. Odour cues are an important component of this information gathering across taxa. Recent laboratory studies have revealed the importance of flexible chemical cues in facilitating social recognition of fishes. These cues are known to be mediated by recent habitat experience and fishes are attracted to individuals that smell like themselves. However, to be relevant to wild populations, where animals may move and forage freely, these cues would have to be temporally flexible and allow spatial resolution. Here, we present data from a study of social recognition in wild populations of three-spined sticklebacks (Gasterosteus aculeatus). Focal fish preferentially associated with conspecifics from the same habitat as themselves. These preferences were changed and updated following translocation of the focal fish to a different site. Further investigation revealed that association preferences changed after 3 h of exposure to different habitat cues. In addition to temporal flexibility, the cues also allowed a high degree of spatial resolution: fish taken from sites 200 m apart produced cues that were sufficiently different to enable the focal fish to discriminate and associate with fish captured near their own home site. The adaptive benefits of this social recognition mechanism remain unclear, though they may allow fish to orient within their social environment and gain current local information. PMID:17284411

  13. Coral reef fish populations can persist without immigration

    PubMed Central

    Salles, Océane C.; Maynard, Jeffrey A.; Joannides, Marc; Barbu, Corentin M.; Saenz-Agudelo, Pablo; Almany, Glenn R.; Berumen, Michael L.; Thorrold, Simon R.; Jones, Geoffrey P.; Planes, Serge

    2015-01-01

    Determining the conditions under which populations may persist requires accurate estimates of demographic parameters, including immigration, local reproductive success, and mortality rates. In marine populations, empirical estimates of these parameters are rare, due at least in part to the pelagic dispersal stage common to most marine organisms. Here, we evaluate population persistence and turnover for a population of orange clownfish, Amphiprion percula, at Kimbe Island in Papua New Guinea. All fish in the population were sampled and genotyped on five occasions at 2-year intervals spanning eight years. The genetic data enabled estimates of reproductive success retained in the same population (reproductive success to self-recruitment), reproductive success exported to other subpopulations (reproductive success to local connectivity), and immigration and mortality rates of sub-adults and adults. Approximately 50% of the recruits were assigned to parents from the Kimbe Island population and this was stable through the sampling period. Stability in the proportion of local and immigrant settlers is likely due to: low annual mortality rates and stable egg production rates, and the short larval stages and sensory capacities of reef fish larvae. Biannual mortality rates ranged from 0.09 to 0.55 and varied significantly spatially. We used these data to parametrize a model that estimated the probability of the Kimbe Island population persisting in the absence of immigration. The Kimbe Island population was found to persist without significant immigration. Model results suggest the island population persists because the largest of the subpopulations are maintained due to having low mortality and high self-recruitment rates. Our results enable managers to appropriately target and scale actions to maximize persistence likelihood as disturbance frequencies increase. PMID:26582017

  14. Coral reef fish populations can persist without immigration.

    PubMed

    Salles, Océane C; Maynard, Jeffrey A; Joannides, Marc; Barbu, Corentin M; Saenz-Agudelo, Pablo; Almany, Glenn R; Berumen, Michael L; Thorrold, Simon R; Jones, Geoffrey P; Planes, Serge

    2015-11-22

    Determining the conditions under which populations may persist requires accurate estimates of demographic parameters, including immigration, local reproductive success, and mortality rates. In marine populations, empirical estimates of these parameters are rare, due at least in part to the pelagic dispersal stage common to most marine organisms. Here, we evaluate population persistence and turnover for a population of orange clownfish, Amphiprion percula, at Kimbe Island in Papua New Guinea. All fish in the population were sampled and genotyped on five occasions at 2-year intervals spanning eight years. The genetic data enabled estimates of reproductive success retained in the same population (reproductive success to self-recruitment), reproductive success exported to other subpopulations (reproductive success to local connectivity), and immigration and mortality rates of sub-adults and adults. Approximately 50% of the recruits were assigned to parents from the Kimbe Island population and this was stable through the sampling period. Stability in the proportion of local and immigrant settlers is likely due to: low annual mortality rates and stable egg production rates, and the short larval stages and sensory capacities of reef fish larvae. Biannual mortality rates ranged from 0.09 to 0.55 and varied significantly spatially. We used these data to parametrize a model that estimated the probability of the Kimbe Island population persisting in the absence of immigration. The Kimbe Island population was found to persist without significant immigration. Model results suggest the island population persists because the largest of the subpopulations are maintained due to having low mortality and high self-recruitment rates. Our results enable managers to appropriately target and scale actions to maximize persistence likelihood as disturbance frequencies increase.

  15. Population Viability Analysis of Riverine Fishes

    SciTech Connect

    Bates, P.; Chandler, J.; Jager, H.I.; Lepla, K.; Van Winkle, W.

    1999-04-12

    Many utilities face conflkts between two goals: cost-efficient hydropower generation and protecting riverine fishes. Research to develop ecological simulation tools that can evaluate alternative mitigation strategies in terms of their benefits to fish populations is vital to informed decision-making. In this paper, we describe our approach to population viability analysis of riverine fishes in general and Snake River white sturgeon in particular. We are finding that the individual-based modeling approach used in previous in-stream flow applications is well suited to addressing questions about the viability of species of concern for several reasons. Chief among these are: (1) the abiIity to represent the effects of individual variation in life history characteristics on predicted population viabili~, (2) the flexibili~ needed to quanti~ the ecological benefits of alternative flow management options by representing spatial and temporal variation in flow and temperaturty and (3) the flexibility needed to quantifi the ecological benefits of non-flow related manipulations (i.e., passage, screening and hatchery supplementation).

  16. Teratogenic effects of selenium in natural populations of freshwater fish.

    PubMed

    Lemly, A D

    1993-10-01

    The prevalence of abnormalities and associated tissue selenium residues were assessed for the fish population of Belews Lake, North Carolina, and two reference lakes in 1975, 1978, 1982, and 1992. Teratogenic defects identified included lordosis, kyphosis, scoliosis, and head, mouth, and fin deformities. Many fish exhibited multiple malformations and some were grossly deformed and distorted in appearance. Other abnormalities observed were edema, exophthalmus, and cataracts. Whole-body tissue residues of selenium in the fishes of Belews Lake were up to 130 times those in the reference lakes and the incidence of abnormalities was some 7 to 70 times greater. Teratogenic defects increased as selenium levels rose between 1975 and 1982 and fell with declining selenium levels between 1982 and 1992 as selenium inputs into Belews Lake were curtailed. The relationship between selenium residues and prevalence of malformations approximated an exponential function (R2 = 0.881, P < 0.01; cubic model) for centrarchids over the range of 1-80 micrograms/g dry wt selenium and 0-70% deformities. This relationship could be useful in evaluating the role of teratogenic effects in warm-water fish populations suspected of having selenium-related reproductive failure. Unique conditions may have existed in Belews Lake which led to the high frequency and persistence of deformities in juvenile and adult fish. In other, less-contaminated locations competition and predation may eliminate malformed individuals in all but the larval life stage. Teratogenesis could be an important, but easily overlooked phenomenon contributing to fishery reproductive failure in selenium-contaminated aquatic habitats.

  17. Short winters threaten temperate fish populations

    PubMed Central

    Farmer, Troy M.; Marschall, Elizabeth A.; Dabrowski, Konrad; Ludsin, Stuart A.

    2015-01-01

    Although climate warming is expected to benefit temperate ectotherms by lengthening the summer growing season, declines in reproductive success following short, warm winters may counter such positive effects. Here we present long-term (1973–2010) field patterns for Lake Erie yellow perch, Perca flavescens, which show that failed annual recruitment events followed short, warm winters. Subsequent laboratory experimentation and field investigations revealed how reduced reproductive success following short, warm winters underlie these observed field patterns. Following short winters, females spawn at warmer temperatures and produce smaller eggs that both hatch at lower rates and produce smaller larvae than females exposed to long winters. Our research suggests that continued climate warming can lead to unanticipated, negative effects on temperate fish populations. PMID:26173734

  18. Short winters threaten temperate fish populations.

    PubMed

    Farmer, Troy M; Marschall, Elizabeth A; Dabrowski, Konrad; Ludsin, Stuart A

    2015-07-15

    Although climate warming is expected to benefit temperate ectotherms by lengthening the summer growing season, declines in reproductive success following short, warm winters may counter such positive effects. Here we present long-term (1973-2010) field patterns for Lake Erie yellow perch, Perca flavescens, which show that failed annual recruitment events followed short, warm winters. Subsequent laboratory experimentation and field investigations revealed how reduced reproductive success following short, warm winters underlie these observed field patterns. Following short winters, females spawn at warmer temperatures and produce smaller eggs that both hatch at lower rates and produce smaller larvae than females exposed to long winters. Our research suggests that continued climate warming can lead to unanticipated, negative effects on temperate fish populations.

  19. Short winters threaten temperate fish populations

    NASA Astrophysics Data System (ADS)

    Farmer, Troy M.; Marschall, Elizabeth A.; Dabrowski, Konrad; Ludsin, Stuart A.

    2015-07-01

    Although climate warming is expected to benefit temperate ectotherms by lengthening the summer growing season, declines in reproductive success following short, warm winters may counter such positive effects. Here we present long-term (1973-2010) field patterns for Lake Erie yellow perch, Perca flavescens, which show that failed annual recruitment events followed short, warm winters. Subsequent laboratory experimentation and field investigations revealed how reduced reproductive success following short, warm winters underlie these observed field patterns. Following short winters, females spawn at warmer temperatures and produce smaller eggs that both hatch at lower rates and produce smaller larvae than females exposed to long winters. Our research suggests that continued climate warming can lead to unanticipated, negative effects on temperate fish populations.

  20. Linking adults and immatures of South African marine fishes.

    PubMed

    Steinke, Dirk; Connell, Allan D; Hebert, Paul D N

    2016-11-01

    The early life-history stages of fishes are poorly known, impeding acquisition of the identifications needed to monitor larval recruitment and year-class strength. A comprehensive database of COI sequences, linked to authoritatively identified voucher specimens, promises to change this situation, representing a significant advance for fisheries science. Barcode records were obtained from 2526 early larvae and pelagic eggs of fishes collected on the inshore shelf within 5 km of the KwaZulu-Natal coast, about 50 km south of Durban, South Africa. Barcodes were also obtained from 3215 adults, representing 946 South African fish species. Using the COI reference library on BOLD based on adults, 89% of the immature fishes could be identified to a species level; they represented 450 species. Most of the uncertain sequences could be assigned to a genus, family, or order; only 92 specimens (4%) were unassigned. Accumulation curves based on inference of phylogenetic diversity indicate near-completeness of the collecting effort. The entire set of adult and larval fishes included 1006 species, representing 43% of all fish species known from South African waters. However, this total included 189 species not previously recorded from this region. The fact that almost 90% of the immatures gained a species identification demonstrates the power and completeness of the DNA barcode reference library for fishes generated during the 10 years of FishBOL.

  1. Reconstructing fish populations using Chaoborus (Diptera: Chaoboridae) remains a review

    NASA Astrophysics Data System (ADS)

    Sweetman, Jon N.; Smol, John P.

    2006-08-01

    Fish are an important component of many lakes, and a valuable resource in many countries, yet knowledge of how fish populations have fluctuated in the past is very limited. One potential source of information on fisheries dynamics is paleolimnology. This paper reviews the use of the sedimentary remains of the dipteran insect Chaoborus (commonly referred to as the phantom midge) in reconstructing past presence or absence of fish populations. We provide a brief overview of the ecology of Chaoborus larvae, and review the factors believed to be important in determining their distribution and abundance. In particular, we outline the important role fish have in structuring chaoborid assemblages. We highlight several recent studies utilizing Chaoborus remains in reconstructing past fish dynamics, including their use in determining the effects of acidification and piscicide additions on fish populations, and to tracing fish introductions into previously fishless lakes. We conclude by discussing the potential applications of other aquatic invertebrates, such as the Cladocera and Chironomidae, to infer changes in fish populations, and suggest that by integrating the information provided by these different proxies, we may further improve our ability to infer changes in past fish populations.

  2. Testing the acceptability of liquid fish oil in older adults.

    PubMed

    Yaxley, Alison; Miller, Michelle D; Fraser, Robert J; Cobiac, Lynne; Crotty, Maria

    2011-01-01

    Inflammatory conditions likely to benefit from fish oil therapy are prevalent in older adults however acceptability in this group is uncertain. This study aimed to assess the palatability of a range of liquid fish oil concentrations, the frequency and extent of side effects, and to summarise any effects on adherence to fish oil therapy in older adults. One hundred patients (>=60 years) completed a randomised, single-blind palatability study, conducted in two parts. In part one, 50 subjects, blinded to random sample order, consumed multiple liquid fish oil samples (2x10%, 40% and 100%). In part two, 50 subjects tasted one concentration, or 100% extra light olive oil (control). Pleasantness of taste was scored on a 5-point Likert scale. Side effects were recorded 24-hr post-tasting. Results of part one showed that 9/50 participants reported increasingly unpleasant taste with increasing fish oil concentration. 14/50 reported unpleasant taste for 100% fish oil vs 7/50 for 10%. 14/50 reported side effects which would not affect compliance with therapy. For part two, 1/12 reported unpleasant taste for 100% vs 0/13 for 10% fish oil or control. 4/50 reported side effects and 2/4 indicated these would prevent ongoing fish oil therapy. The authors conclude that taste itself is not a deterrent to fish oil therapy. Furthermore, reported adverse effects may not be a true reaction to fish oil, or dissuade patients from compliance. Liquid fish oil supplements are acceptable to older adults, therefore should be investigated as a therapy for geriatric conditions.

  3. A quantitative risk-benefit analysis of changes in population fish consumption.

    PubMed

    Cohen, Joshua T; Bellinger, David C; Connor, William E; Kris-Etherton, Penny M; Lawrence, Robert S; Savitz, David A; Shaywitz, Bennett A; Teutsch, Steven M; Gray, George M

    2005-11-01

    Although a rich source of n-3 polyunsaturated fatty acids (PUFAs) that may confer multiple health benefits, some fish contain methyl mercury (MeHg), which may harm the developing fetus. U.S. government recommendations for women of childbearing age are to modify consumption of high-MeHg fish, while recommendations encourage fish consumption among the general population because of nutritional benefits. To investigate the aggregate impacts of hypothetical shifts in fish consumption, the Harvard Center for Risk Analysis convened an expert panel (see acknowledgements). Effects investigated include prenatal cognitive development, coronary heart disease mortality, and stroke. Substitution of fish with high MeHg concentrations with fish containing less MeHg among women of childbearing age yields substantial developmental benefits and few negative impacts. However, if women instead decrease fish consumption, countervailing risks substantially reduce net benefits. If other adults (mistakenly and inappropriately) also reduce their fish consumption, the net public health impact is negative. Although high compliance with recommended fish consumption patterns can improve public health, unintended shifts in consumption can lead to public health losses. Risk managers should investigate and carefully consider how populations will respond to interventions, how those responses will influence nutrient intake and contaminant exposure, and how these changes will affect aggregate public health.

  4. Spatial structuring within a reservoir fish population: implications for management

    USGS Publications Warehouse

    Stewart, David R.; Long, James M.; Shoup, Daniel E.

    2014-01-01

    Spatial structuring in reservoir fish populations can exist because of environmental gradients, species-specific behaviour, or even localised fishing effort. The present study investigated whether white crappie exhibited evidence of improved population structure where the northern more productive half of a lake is closed to fishing to provide waterfowl hunting opportunities. Population response to angling was modelled for each substock of white crappie (north (protected) and south (unprotected) areas), the entire lake (single-stock model) and by combining simulations of the two independent substock models (additive model). White crappie in the protected area were more abundant, consisting of larger, older individuals, and exhibited a lower total annual mortality rate than in the unprotected area. Population modelling found that fishing mortality rates between 0.1 and 0.3 resulted in sustainable populations (spawning potential ratios (SPR) >0.30). The population in the unprotected area appeared to be more resilient (SPR > 0.30) at the higher fishing intensities (0.35–0.55). Considered additively, the whole-lake fishery appeared more resilient than when modelled as a single-panmictic stock. These results provided evidence of spatial structuring in reservoir fish populations, and we recommend model assessments used to guide management decisions should consider those spatial differences in other populations where they exist.

  5. Recovery of a wild fish population from whole-lake additions of a synthetic estrogen.

    PubMed

    Blanchfield, Paul J; Kidd, Karen A; Docker, Margaret F; Palace, Vince P; Park, Brad J; Postma, Lianne D

    2015-03-03

    Despite widespread recognition that municipal wastewaters contain natural and synthetic estrogens, which interfere with development and reproduction of fishes in freshwaters worldwide, there are limited data on the extent to which natural populations of fish can recover from exposure to these compounds. We conducted whole-lake additions of an active component of the birth control pill (17α-ethynylestradiol; EE2) that resulted in the collapse of the fathead minnow (Pimephales promelas) population. Here we quantify physiological, population, and genetic characteristics of this population over the 7 years after EE2 additions stopped to determine if complete recovery was possible. By 3 years post-treatment, whole-body vitellogenin concentrations in male fathead minnow had returned to baseline, and testicular abnormalities were absent. In the spring of the fourth year, adult size-frequency distribution and abundance had returned to pretreatment levels. Microsatellite analyses clearly showed that postrecovery fish were descendants of the original EE2-treated population. Results from this whole-lake experiment demonstrate that fish can recover from EE2 exposure at the biochemical through population levels, although the timelines to do so are long for multigenerational exposures. These results suggest that wastewater treatment facilities that reduce discharges of estrogens and their mimics can improve the health of resident fish populations in their receiving environments.

  6. Fish intake is associated with slower cognitive decline in Chinese older adults.

    PubMed

    Qin, Bo; Plassman, Brenda L; Edwards, Lloyd J; Popkin, Barry M; Adair, Linda S; Mendez, Michelle A

    2014-10-01

    Modifiable lifestyle changes, including dietary changes, could translate into a great reduction in the global burden of cognitive impairment and dementia. Few studies evaluated the benefits of fish intake for delaying cognitive decline, and no studies were conducted in a Chinese population, which may differ with respect to types, amounts, and correlates of fish consumption compared with Western populations. We hypothesized that higher consumption of fish would predict slower decline in cognitive function, independent of a wide range of potential confounders. This prospective cohort study comprised 1566 community-dwelling adults aged ≥ 55 y who completed a cognitive screening test at ≥2 waves of the China Health and Nutrition Survey in 1997, 2000, or 2004, with a mean follow-up of 5.3 y [age at entry (mean ± SD): 63 ± 6 y]. Diet was measured by 3-d 24-h recalls at baseline. Outcomes included repeated measures of global cognitive scores (baseline mean ± SD: 19 ± 6 points), composite cognitive Z-scores (standardized units), and standardized verbal memory scores (standardized units). Multivariable-adjusted linear mixed-effects models were used to evaluate the relation of fish intake with changes in cognitive scores. Age was found to significantly modify the association between fish consumption and cognitive change (P = 0.007). Among adults aged ≥ 65 y, compared with individuals who consumed <1 serving/wk (i.e., 100 g) fish, the mean annual rate of global cognitive decline was reduced by 0.35 point (95% CI: 0.13, 0.58) among those consuming ≥ 1 serving/wk, equivalent to the disparity associated with 1.6 y of age. Fish consumption was also associated with a slower decline in composite and verbal memory scores. No associations were observed among adults aged 55-64 y. Our findings suggest a potential role of fish consumption as a modifiable dietary factor to reduce the rate of cognitive decline in later life.

  7. May organic pollutants affect fish populations in the North Sea?

    PubMed

    Hylland, Ketil; Beyer, Jonny; Berntssen, Marc; Klungsøyr, Jarle; Lang, Thomas; Balk, Lennart

    2006-01-08

    The North Sea is a highly productive area with large fish populations that have been extensively harvested over the past century. North Sea fisheries remain important to the surrounding countries despite declining fish stocks over the past decades. The main reason for declining fish stocks is nearly certainly overfishing, but other environmental pressures also affect fish populations, such as eutrophication, climate change, and exposure to metals and organic pollutants, including polyaromatic hydrocarbons (PAHs), alkylphenols, and organochlorine compounds. There are three main sources of organic pollutants in the North Sea: atmospheric, land-based sources, and inputs from offshore gas and oil installations. All three sources contribute to elevated concentrations of organic pollutants in the North Sea compared to the Norwegian Sea. There is evidence that chlorinated organic contaminants were present in sufficiently high concentrations in the southern North Sea two decades ago, to alter embryonal development in fish. The results from extensive, long-term monitoring programs show that some diseases decreased whereas other increased in the southern North Sea and that, among other factors, contaminants may play a role in the temporal changes recorded in disease prevalence. Recent studies demonstrated that components in offshore effluents may affect fish reproduction and that tissues of fish near oil rigs are structurally different to tissues of fish from reference areas. Data on effluents from offshore activities have recently become available through an international workshop (BECPELAG) and follow-up studies.

  8. Adult height, nutrition, and population health

    PubMed Central

    Perkins, Jessica M.; Subramanian, S.V.; Davey Smith, George

    2016-01-01

    In this review, the potential causes and consequences of adult height, a measure of cumulative net nutrition, in modern populations are summarized. The mechanisms linking adult height and health are examined, with a focus on the role of potential confounders. Evidence across studies indicates that short adult height (reflecting growth retardation) in low- and middle-income countries is driven by environmental conditions, especially net nutrition during early years. Some of the associations of height with health and social outcomes potentially reflect the association between these environmental factors and such outcomes. These conditions are manifested in the substantial differences in adult height that exist between and within countries and over time. This review suggests that adult height is a useful marker of variation in cumulative net nutrition, biological deprivation, and standard of living between and within populations and should be routinely measured. Linkages between adult height and health, within and across generations, suggest that adult height may be a potential tool for monitoring health conditions and that programs focused on offspring outcomes may consider maternal height as a potentially important influence. PMID:26928678

  9. Adult height, nutrition, and population health.

    PubMed

    Perkins, Jessica M; Subramanian, S V; Davey Smith, George; Özaltin, Emre

    2016-03-01

    In this review, the potential causes and consequences of adult height, a measure of cumulative net nutrition, in modern populations are summarized. The mechanisms linking adult height and health are examined, with a focus on the role of potential confounders. Evidence across studies indicates that short adult height (reflecting growth retardation) in low- and middle-income countries is driven by environmental conditions, especially net nutrition during early years. Some of the associations of height with health and social outcomes potentially reflect the association between these environmental factors and such outcomes. These conditions are manifested in the substantial differences in adult height that exist between and within countries and over time. This review suggests that adult height is a useful marker of variation in cumulative net nutrition, biological deprivation, and standard of living between and within populations and should be routinely measured. Linkages between adult height and health, within and across generations, suggest that adult height may be a potential tool for monitoring health conditions and that programs focused on offspring outcomes may consider maternal height as a potentially important influence.

  10. Modelling production per unit of food consumed in fish populations.

    PubMed

    Wiff, Rodrigo; Barrientos, Mauricio A; Milessi, Andrés C; Quiroz, J C; Harwood, John

    2015-01-21

    The ratio of production-to-consumption (ρ) reflects how efficiently a population can transform ingested food into biomass. Usually this ratio is estimated by separately integrating cohort per-recruit production and consumption per unit of biomass. Estimates of ρ from cohort analysis differ from those that consider the whole population, because fish populations are usually composed of cohorts that differ in their relative abundance. Cohort models for ρ also assume a stable age-structure and a constant population size (stationary condition). This may preclude their application to harvested populations, in which variations in fishing mortality and recruitment will affect age-structure. In this paper, we propose a different framework for estimating (ρ) in which production and consumption are modelled simultaneously to produce a population estimator of ρ. Food consumption is inferred from the physiological concepts underpinning the generalised von Bertalanffy growth function (VBGF). This general framework allows the effects of different age-structures to be explored, with a stationary population as a special case. Three models with different complexities, depending mostly on what assumptions are made about age-structure, are explored. The full data model requires knowledge about food assimilation efficiency, parameters of the VBGF and the relative proportion of individuals at age a at time y (Py(a)). A simpler model, which requires less data, is based on the stationary assumption. Model results are compared with estimates from cohort models for ρ using simulated fish populations of different lifespans. The models proposed here were also applied to three fish populations that are targets of commercial fisheries in the south-east Pacific. Uncertainty in the estimation of ρ was evaluated using a resampling approach. Simulation showed that cohort and population models produce different estimates for ρ and those differences depend on lifespan, fishing mortality and

  11. Population-regulating processes during the adult phase in flatfish

    NASA Astrophysics Data System (ADS)

    Rijnsdorp, A. D.

    Flatfish support major fisheries and the study of regulatory processes are of paramount importance for evaluating the resilience of the resource to exploitation. This paper reviews the evidence for processes operating during the adult phase that may 1. generate interannual variability in recruitment; 2. contribute to population regulation through density-dependent growth, density-dependent ripening of adults and density-dependent egg production. With regard to (1), there is evidence that in the adult phase processes do occur that may generate recruitment variability through variation in size-specific fecundity, contraction of spawning season, reduction in egg quality, change in sex ratio and size composition of the adult population. However, time series of recruitment do not provide support for this hypothesis. With regard to (2), there is ample evidence that exploitation of flatfish coincides with an increase in growth, although the mechanisms involved are not always clear. The presence of density-dependent growth in the adult phase of unexploited populations appears to be the most likely explanation in some cases. From the early years of exploitation of flatfish stocks inhabiting cold waters, evidence exists that adult fish do not spawn each year. Fecundity schedules show annual variations, but the available information suggests that size-specific fecundity is stable over a broad range of population abundance and may only decrease at high population abundance. The analysis is complicated by the possibility of a trade-off between egg numbers and egg size. Nevertheless, a density-dependent decrease in growth will automatically result in a decrease in absolute fecundity because of the reduced body size. The potential contribution of these regulatory effects on population regulation is explored. Results indicate that density-dependent ripening and absolute fecundity, mediated through density-dependent growth, may control recruitment at high levels of population

  12. Effects of a Novel Fish Transport System on the Health of Adult Fall Chinook Salmon

    SciTech Connect

    Geist, David R.; Colotelo, Alison H.; Linley, Timothy J.; Wagner, Katie A.; Miracle, Ann L.

    2016-12-01

    Movement past hydroelectric dams and related in-river structures has important implications for habitat connectivity and population persistence in migratory fish. A major problem is that many of these structures lack effective fish passage facilities, which can fragment spawning and rearing areas and negatively impact recruitment. While traditional fish passage facilities (e.g., ladders, trap and haul) can effectively enable fish to pass over barriers, their capital or operational costs can be significant. We evaluated the utility of a novel transport device that utilizes a flexible tube with differential internal air pressure to pass fish around in-river barriers. Three treatments and a control group were tested. In two of the treatments, adult fall Chinook Salmon nearing maturation were transported through the device via two lengths of tube (12 or 77 m) and their injury, stress, and immune system responses and reproductive function were compared to a third treatment where fish were moved by a standard trap and haul method and also to a control group. We observed no significant differences among the treatment or control groups in post-treatment adult survival, injury or stress. Indicators of immune system response and reproductive readiness were also not significantly different among the four groups. Egg survival was significantly different among the groups, but the differences were highly variable within groups and not consistent with the duration of treatment or degree of handling. Taken together, the results suggest the device did not injure or alter normal physiological functioning of adult fall Chinook Salmon nearing maturation and may provide an effective method for transporting such fish around in-river barriers during their spawning migration. Keywords: Whooshh, transport, in-stream barriers, hydropower

  13. Frequency of Fish Intake and Diabetes among Adult Indians

    PubMed Central

    Agrawal, Sutapa; Millett, Christopher; Subramanian, S. V.; Ebrahim, Shah

    2014-01-01

    Objectives: Recent studies have shown that the choice of foods plays a role in diabetes prevention. However, little empirical evidence on this association exists in developing countries. We aimed to examine the association between frequency of fish intake and self-reported diabetes status among adult men and women in India. Methods: Analysis of cross-sectional data from participants in India's third National Family Health Survey conducted during 2005–2006 was performed. Associations between fish intake, determined by frequency of consumption (daily, weekly, occasionally, and never), and self-reported diabetes were estimated using multivariable-adjusted models in 99,574 women, 56,742 men, and 39,257 couples aged 20–49 years after adjusting for frequency of consumption of other food items, body mass index (BMI) status, tobacco smoking, alcohol drinking, watching television, age, education, living standard of the household, and place of residence. Results: After adjustment for other dietary, lifestyle, and socioeconomic and demographic characteristics, odds of diabetes were 2 times higher (odds ratio [OR]: 2.02; 95% confidence interval [CI], 1.59–2.57; p < 0.0001) among those who reported consuming fish daily compared to those who never consumed fish. Weekly fish intake was also associated with a higher odds of having diabetes (OR: 1.55; 95% CI, 1.25–1.93; p < 0.0001). The adjusted effect of daily fish intake on diabetes was greater among men (OR: 2.46; 95% CI, 1.66–3.65) than among women (OR: 1.72; 95% CI, 1.26–2.33). In cross-spousal sensitivity analysis, the odds of a husband having diabetes was also associated with wife's daily/weekly consumption of fish (OR: 1.36; 95% CI, 0.92–2.01) and the odds of a wife having diabetes was also associated with husband's daily/weekly consumption of fish (OR: 1.21; 95% CI, 0.87–1.68). Conclusions: In a large nationally representative sample of adult men and women in India, daily or weekly fish intake was

  14. Evaluation of general response patterns as a diagnostic tool to determining contaminant impacts on fish populations

    SciTech Connect

    Jaworska, J.S.; Barnthouse, L.W.; Rose, K.A.

    1995-12-31

    Five General Response Patterns by fish populations exposed to stress were hypothesized by P. Colby and K. Munkittrick and D. Dixon. The authors used an individual based model of walleye and yellow perch configured for Oneida Lake, NY to test the generality of these patterns. They compared the yellow perch population responses in mean age, size at age, fraction mature at age, individual fecundity and density under 5 stress conditions. The stresses imposed were: (1) adults mortality; (2) eggs mortality (3) metabolic impacts on juveniles; (4) indirect effects from predator level -- increased predator mortality; (5) indirect effects form prey level -- reduced carrying capacity. Modeled yellow perch responses different from the responses hypothesized by Colby/Munkittrick and Dixon. Their analysis shows that the strength of predator-prey coupling must be considered when using patterns of growth, mortality and reproduction to infer the identity of stressors influencing fish populations.

  15. Effects of fire on fish populations: Landscape perspectives on persistance of native fishes and nonnative fish invasions

    USGS Publications Warehouse

    Dunham, J.B.; Young, M.; Gresswell, Robert E.; Rieman, B.

    2003-01-01

    Our limited understanding of the short and long-term effects of fire on fish contributes to considerable uncertainty in assessments of the risks and benefits of fire management alternatives. A primary concern among the many potential effects of fire is the effects of fire and fire management on persistence of native fish populations. Limited evidence suggests vulnerability of fish to fire is contingent upon the quality of affected habitats, the amount and distribution of habitat (habitat fragmentation), and habitat specificity of the species in question. Species with narrow habitat requirements in highly degraded and fragmented systems are likely to be most vulnerable to fire and fire-related disturbance. In addition to effects of fire on native fish, there are growing concerns about the effects of fire on nonnative fish invasions. The role of fire in facilitating invasions by nonnative fishes is unknown, but experience with other species suggests some forms of disturbance associated with fire may facilitate invasion. Management efforts to promote persistence of fishes in fire-prone landscapes can take the form of four basic alternatives: (1) pre-fire management; (2) post-fire management; (3) managing fire itself (e.g. fire fighting); and (4) monitoring and adaptive management. Among these alternatives, pre-fire management is likely to be most effective. Effective pre-fire management activities will address factors that may render fish populations more vulnerable to the effects of fire (e.g. habitat degradation, fragmentation, and nonnative species). Post-fire management is also potentially important, but suffers from being a reactive approach that may not address threats in time to avert them. Managing fire itself can be important in some contexts, but negative consequences for fish populations are possible (e.g. toxicity of fire fighting chemicals to fish). Monitoring and adaptive management can provide important new information for evaluating alternatives, but

  16. Population pharmacokinetics of micafungin in adult patients.

    PubMed

    Gumbo, Tawanda; Hiemenz, John; Ma, Lei; Keirns, James J; Buell, Donald N; Drusano, George L

    2008-03-01

    We performed population pharmacokinetic analysis of micafungin in adult patients treated with doses between 12.5 and 200 mg/day. Our analysis identified a breakpoint patient weight of 66.3 kg above which serum clearance increased by approximately 50%. Patients with weight >66.3 kg may need larger doses to achieve similar exposures to those <66.3 kg. However, the clinical implications are still unknown.

  17. Effects of human population density and proximity to markets on coral reef fishes vulnerable to extinction by fishing.

    PubMed

    Brewer, T D; Cinner, J E; Green, A; Pressey, R L

    2013-06-01

    Coral reef fisheries are crucial to the livelihoods of tens of millions of people; yet, widespread habitat degradation and unsustainable fishing are causing severe depletion of stocks of reef fish. Understanding how social and economic factors, such as human population density, access to external markets, and modernization interact with fishing and habitat degradation to affect fish stocks is vital to sustainable management of coral reef fisheries. We used fish survey data, national social and economic data, and path analyses to assess whether these factors explain variation in biomass of coral reef fishes among 25 sites in Solomon Islands. We categorized fishes into 3 groups on the basis of life-history characteristics associated with vulnerability to extinction by fishing (high, medium, and low vulnerability). The biomass of fish with low vulnerability was positively related to habitat condition. The biomass of fishes with high vulnerability was negatively related to fishing conducted with efficient gear. Use of efficient gear, in turn, was strongly and positively related to both population density and market proximity. This result suggests local population pressure and external markets have additive negative effects on vulnerable reef fish. Biomass of the fish of medium vulnerability was not explained by fishing intensity or habitat condition, which suggests these species may be relatively resilient to both habitat degradation and fishing.

  18. Empowerment of Fisher Women of Siluvaipatti Fishing Village of Tuticorin, Southeast Coast of India through Adult Education and ICT Training

    ERIC Educational Resources Information Center

    Patterson, Jamila; Linden, Eva; Bierbrier, Christin; Lofgren, Inger; Wilhelmsson, Dan; Edward, J. K. Patterson

    2008-01-01

    This paper focuses on adult education and information and communication technologies (ICT) training to fisherwomen of Siluvaipatti fishing village in Tuticorin district of Tamil Nadu State, southeastern India. The total families in this village are 209 with population 899 (Male: 442; Female: 457). The education level is generally good in…

  19. Evaluation of Midwater Trawl Selectivity and its Influence on Acoustic-Based Fish Population Surveys

    NASA Astrophysics Data System (ADS)

    Williams, Kresimir

    Trawls are used extensively during fisheries abundance surveys to derive estimates of fish density and, in the case of acoustic-based surveys, to identify acoustically sampled fish populations. However, trawls are selective in what fish they retain, resulting in biased estimates of density, species, and size compositions. Selectivity of the midwater trawl used in acoustic-based surveys of walleye pollock (Theragra chalcogramma) was evaluated using multiple methods. The effects of trawl selectivity on the acoustic-based survey abundance estimates and the stock assessment were evaluated for the Gulf of Alaska walleye pollock population. Selectivity was quantified using recapture, or pocket, nets attached to the outside of the trawl. Pocket net catches were modeled using a hierarchical Bayesian model to provide uncertainty in selectivity parameter estimates. Significant under-sampling of juvenile pollock by the midwater trawl was found, with lengths at 50% retention ranging from 14--26 cm over three experiments. Escapement was found to be light dependent, with more fish escaping in dark conditions. Highest escapement rates were observed in the aft of the trawl near to the codend though the bottom panel of the trawl. The behavioral mechanisms involved in the process of herding and escapement were evaluated using stereo-cameras, a DIDSON high frequency imaging sonar, and pocket nets. Fish maintained greater distances from the trawl panel during daylight, suggesting trawl modifications such as increased visibility of netting materials may evoke stronger herding responses and increased retention of fish. Selectivity and catchability of pollock by the midwater trawl was also investigated using acoustic density as an independent estimate of fish abundance to compare with trawl catches. A modeling framework was developed to evaluate potential explanatory factors for selectivity and catchability. Selectivity estimates were dependent on which vessel was used for the survey

  20. Evidence for harvest-induced maternal influences on the reproductive rates of fish populations.

    PubMed

    Venturelli, Paul A; Shuter, Brian J; Murphy, Cheryl A

    2009-03-07

    Knowledge of the relationship between the number of offspring produced (recruitment) and adult abundance is fundamental to forecasting the dynamics of an exploited population. Although small-scale experiments have documented the importance of maternal quality to offspring survival in plants and animals, the effects of this association on the recruitment dynamics of exploited populations are largely unknown. Here, we present results from both a simple population model and a meta-analysis of time-series data from 25 species of exploited marine fishes that suggest that a population of older, larger individuals has a higher maximum reproductive rate than an equivalent population of younger, smaller individuals, and that this difference increases with the reproductive lifespan of the population. These findings (i) establish an empirical link between population age structure and reproductive rate that is consistent with strong effects of maternal quality on population dynamics and (ii) provide further evidence that extended age structure is essential to the sustainability of many exploited fish stocks.

  1. Evidence for harvest-induced maternal influences on the reproductive rates of fish populations

    PubMed Central

    Venturelli, Paul A.; Shuter, Brian J.; Murphy, Cheryl A.

    2008-01-01

    Knowledge of the relationship between the number of offspring produced (recruitment) and adult abundance is fundamental to forecasting the dynamics of an exploited population. Although small-scale experiments have documented the importance of maternal quality to offspring survival in plants and animals, the effects of this association on the recruitment dynamics of exploited populations are largely unknown. Here, we present results from both a simple population model and a meta-analysis of time-series data from 25 species of exploited marine fishes that suggest that a population of older, larger individuals has a higher maximum reproductive rate than an equivalent population of younger, smaller individuals, and that this difference increases with the reproductive lifespan of the population. These findings (i) establish an empirical link between population age structure and reproductive rate that is consistent with strong effects of maternal quality on population dynamics and (ii) provide further evidence that extended age structure is essential to the sustainability of many exploited fish stocks. PMID:19033140

  2. Improving the assessment of instream flow needs for fish populations

    SciTech Connect

    Sale, M.J. ); Otto, R.G. and Associates, Arlington, VA )

    1991-01-01

    Instream flow requirements are one of the most frequent and most costly environmental issues that must be addressed in developing hydroelectric projects. Existing assessment methods for determining instream flow requirements have been criticized for not including all the biological response mechanisms that regulate fishery resources. A new project has been initiated to study the biological responses of fish populations to altered stream flows and to develop improved ways of managing instream flows. 21 refs., 3 figs.

  3. Evaluating and understanding fish health risks and their consequences in propagated and free-ranging fish populations

    USGS Publications Warehouse

    Moffitt, C.M.; Haukenes, A.H.; Williams, C.J.

    2005-01-01

    Fishery managers and resource conservationists are increasingly interested in understanding the fish health and disease risks of free-ranging fishes and whether propagated fishes or features and practices used at fish culture facilities pose a health risk to free-ranging populations. Disease agents are present in most both captive and all free-ranging fish populations, but the consequences and extent of infections in free-ranging populations are often difficult to measure, control, and understand. Sampling methods, protocols, and assay techniques developed to assess the health of captive populations are not as applicable for assessments of free-ranging fishes. The use of chemicals and therapeutics to control diseases and parasites in propagated fishes likely reduces the risk of introducing specific pathogens into the environment, but control measures may have localized effects on the environment surrounding fish culture facilities. To understand health risks of propagated and free ranging fishes, we must consider fish populations, culture facilities, fish releases, and their interactions within the greater geospatial features of the aquatic environment. ?? 2004 by the American Fisheries Society.

  4. Compensatory mechanisms in fish populations: Literature reviews: Volume 2, Compensation in fish populations subject to catastrophic impact: Final report

    SciTech Connect

    Jude, D.J.; Mansfield, P.J.; Schneeberger, P.J.; Wojcik, J.A.

    1987-05-01

    This study comprises an extensive literature review, critical evaluations of case histories, and considered recommendations for future research on the mechanisms and extent of compensation by various fish species subject to catastrophic impacts. ''Catastrophic impact'' was defined as an event which removes some limitation (such as food or space) on a fish population. Those events studied included new species introduction, toxic spills, exploitation of specific fish populations, and drawdown. The fish studied each had more than one compensatory mechanism available, and thus were able to respond to a catastrophic event even if an option was removed. Predation, overfishing, competition, disease, and parasitism are all potential catastrophies, but were found not to cause a catastrophic impact (except in special cases). In general, compensatory responses were determined to vary widely, even for species which perform fairly similar functions in an ecosystem. The extensive nature of this study, however, pointed up the many data gaps in the existing literature; recommendations are therefore made for followup research and expansion of ongoing monitoring programs, based on an evaluation of their relative importance.

  5. Evaluation of fish population effects due to creosote exposure in aquatic mesocosms

    SciTech Connect

    Munro, K.A.; Bestari, K.T.; Robinson, R.D.; Gensemer, R.W.; Solomon, K.R.

    1995-12-31

    Creosote is a coal tar distillate, consisting primarily of a mixture of polycyclic aromatic hydrocarbons (PAHs). Its widespread use as a wood preservative presents a potential risk to aquatic ecosystems. Studying fish responses in mesocosms enabled evaluation of the total impact of creosote exposure, resulting from both direct toxic effects and indirect community-level interactions. Two methods of creosote application were used: liquid creosote treatment and creosote-impregnated pilings treatment. Survival and egg production of adult Fathead minnows (Pimephales promelas) were monitored for two successive 30-day periods (0--30 and 35--65 days posttreatment). In addition, juvenile Fatheads produced during these periods were harvested 90 days posttreatment, to determine impacts to population weight/frequency distributions. Results for both field seasons showed that higher creosote concentrations caused strong decreases in both adult and juvenile survival, as well as egg production. Bile fluorescence levels measured at intervals during the exposure period reflected changes in total aqueous PAH concentrations in the mesocosms. Effects of creosote exposure on survival of adult fish were markedly reduced for fish introduced to ponds 35 days posttreatment compared to those exposed in the initial 0--30 day period.

  6. Adult and larval traits as determinants of geographic range size among tropical reef fishes

    PubMed Central

    Luiz, Osmar J.; Allen, Andrew P.; Robertson, D. Ross; Floeter, Sergio R.; Kulbicki, Michel; Vigliola, Laurent; Becheler, Ronan; Madin, Joshua S.

    2013-01-01

    Most marine organisms disperse via ocean currents as larvae, so it is often assumed that larval-stage duration is the primary determinant of geographic range size. However, empirical tests of this relationship have yielded mixed results, and alternative hypotheses have rarely been considered. Here we assess the relative influence of adult and larval-traits on geographic range size using a global dataset encompassing 590 species of tropical reef fishes in 47 families, the largest compilation of such data to date for any marine group. We analyze this database using linear mixed-effect models to control for phylogeny and geographical limits on range size. Our analysis indicates that three adult traits likely to affect the capacity of new colonizers to survive and establish reproductive populations (body size, schooling behavior, and nocturnal activity) are equal or better predictors of geographic range size than pelagic larval duration. We conclude that adult life-history traits that affect the postdispersal persistence of new populations are primary determinants of successful range extension and, consequently, of geographic range size among tropical reef fishes. PMID:24065830

  7. Evaluation of Juvenile Fish Bypass and Adult Fish Facilities at Water Diversions in the Umatilla River; 1992 Annual Report.

    SciTech Connect

    Knapp, Suzanne M.

    1993-03-01

    We report on our progress from October 1991 through September 1992 in evaluating juvenile fish bypass facilities at Three Mile Falls and Westland dams on the Umatilla River. We also report on our progress from October 1991 through June 1992 in evaluating adult fish passage in the lower Umatilla River and adult fish passage facilities at Three Mile Falls Dam. The study is a cooperative effort by the Oregon Department of Fish and Wildlife (ODFW) and the Confederated Tribes of the Umatilla Indian Reservation (CTUIR). These are the study objectives addressed by ODFW and CTUIR: (1) Report A (ODFW): To evaluate the juvenile fish bypass facility in the West Extension Irrigation District Canal at Three Mile Falls Dam and document juvenile salmonid passage through the juvenile fish bypass facility and east-bank adult fish ladder. To measure velocity and develop trap designs at Westland Dam. (2) Report B (CTUIR): To examine the passage of adult salmonids at Three Mile Falls Dam. The study is part of a program to rehabilitate anadromous fish stocks in the Umatilla River Basin, including restoration of coho salmon (Oncorhynchus kisutch) and chinook salmon (Oncorhynchus tshawytscha), as well as enhancement of summer steelhead (Oncorhynchus mykiss).

  8. Major pathways by which climate may force marine fish populations

    NASA Astrophysics Data System (ADS)

    Ottersen, Geir; Kim, Suam; Huse, Geir; Polovina, Jeffrey J.; Stenseth, Nils Chr.

    2010-02-01

    Climate may affect marine fish populations through many different pathways, operating at a variety of temporal and spatial scales. Climate impacts may work their way bottom up through the food web or affect higher trophic levels more directly. In this review we try to disentangle and summarize some of the current knowledge made available through the rapidly increasing literature on the topic, with particular emphasis on the work within the Global Ocean Ecosystems Dynamics (GLOBEC) programme. We first consider different classification schemes and hypotheses relating climate through physical features of the ocean to population patterns. The response of a population or community to climate may be linear or non-linear, direct or indirect. The hypotheses may be classified according to the form of physical features in operation as being related to mixing, advection or temperature. The bulk of the paper is devoted to a region-by-region presentation and discussion of examples relating climate variability to marine fish populations. It is slanted towards the North Atlantic and North Pacific, but the tropical Pacific is also covered. By means of different categorization methods we compare climate responses between ecosystems. We conclude that the use of such classification schemes allows for a more precise description of the various ecosystems particular properties and facilitates inter-regional comparison.

  9. Native fish population and habitat study, Santa Ana River, California

    USGS Publications Warehouse

    Wulff, Marissa L.; Brown, Larry R.; May, Jason

    2017-01-01

    Collection of additional data on the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) has been identified as a needed task to support development of the upper Santa Ana River Habitat Conservation Plan (HCP; http://www.uppersarhcp.com/). The ability to monitor population abundance and understanding the habitats used by species are important when developing such plans. The Santa Ana Sucker (Catostomus santaanae) is listed as a threatened species under federal legislation and is considered a species of special concern in California by the California Department of Fish and Wildlife (Moyle 2002). The Arroyo Chub (Gila orcutti) is considered a species of special concern in California by the California Department of Fish and Wildlife (Moyle 2002). Both species are present in the Santa Ana River watershed in the area being evaluated for establishment of the upper Santa Ana River Habitat Conservation Plan (HCP; http://www.uppersarhcp.com/). The HCP is a collaborative effort involving the water resource agencies of the Santa Ana River Watershed, the US Fish and Wildlife Service, California Department of Fish and Wildlife, and other government agencies and stakeholder organizations. The goals of the HCP are to: 1) enable the water resource agencies to provide a reliable water supply for human uses; 2) conserve and maintain natural rivers and streams that provide habitat for a diversity of unique and rare species; and 3) maintain recreational opportunities for activities such as hiking, fishing, and wildlife viewing, provided by the protection of these habitats and the river systems they depend on. The HCP will specify how species and their habitats will be protected and managed in the future and will provide the incidental take permits needed by the water resource agencies under the federal and State endangered species acts to maintain, operate, and improve their water resource infrastructure. Although the Santa Ana Sucker has been the subject of

  10. Energetic and ecological constraints on population density of reef fishes

    PubMed Central

    Barneche, D. R.; Kulbicki, M.; Floeter, S. R.; Friedlander, A. M.; Allen, A. P.

    2016-01-01

    Population ecology has classically focused on pairwise species interactions, hindering the description of general patterns and processes of population abundance at large spatial scales. Here we use the metabolic theory of ecology as a framework to formulate and test a model that yields predictions linking population density to the physiological constraints of body size and temperature on individual metabolism, and the ecological constraints of trophic structure and species richness on energy partitioning among species. Our model was tested by applying Bayesian quantile regression to a comprehensive reef-fish community database, from which we extracted density data for 5609 populations spread across 49 sites around the world. Our results indicate that population density declines markedly with increases in community species richness and that, after accounting for richness, energetic constraints are manifested most strongly for the most abundant species, which generally are of small body size and occupy lower trophic groups. Overall, our findings suggest that, at the global scale, factors associated with community species richness are the major drivers of variation in population density. Given that populations of species-rich tropical systems exhibit markedly lower maximum densities, they may be particularly susceptible to stochastic extinction. PMID:26791611

  11. Energetic and ecological constraints on population density of reef fishes.

    PubMed

    Barneche, D R; Kulbicki, M; Floeter, S R; Friedlander, A M; Allen, A P

    2016-01-27

    Population ecology has classically focused on pairwise species interactions, hindering the description of general patterns and processes of population abundance at large spatial scales. Here we use the metabolic theory of ecology as a framework to formulate and test a model that yields predictions linking population density to the physiological constraints of body size and temperature on individual metabolism, and the ecological constraints of trophic structure and species richness on energy partitioning among species. Our model was tested by applying Bayesian quantile regression to a comprehensive reef-fish community database, from which we extracted density data for 5609 populations spread across 49 sites around the world. Our results indicate that population density declines markedly with increases in community species richness and that, after accounting for richness, energetic constraints are manifested most strongly for the most abundant species, which generally are of small body size and occupy lower trophic groups. Overall, our findings suggest that, at the global scale, factors associated with community species richness are the major drivers of variation in population density. Given that populations of species-rich tropical systems exhibit markedly lower maximum densities, they may be particularly susceptible to stochastic extinction.

  12. Long-Term Changes in the Distributions of Larval and Adult Fish in the Northeast U.S. Shelf Ecosystem

    PubMed Central

    2015-01-01

    Many studies have documented long-term changes in adult marine fish distributions and linked these changes to climate change and multi-decadal climate variability. Most marine fish, however, have complex life histories with morphologically distinct stages, which use different habitats. Shifts in distribution of one stage may affect the connectivity between life stages and thereby impact population processes including spawning and recruitment. Specifically, many marine fish species have a planktonic larval stage, which lasts from weeks to months. We compared the spatial distribution and seasonal occurrence of larval fish in the Northeast U.S. Shelf Ecosystem to test whether spatial and temporal distributions changed between two decades. Two large-scale ichthyoplankton programs sampled using similar methods and spatial domain each decade. Adult distributions from a long-term bottom trawl survey over the same time period and spatial area were also analyzed using the same analytical framework to compare changes in larval and adult distributions between the two decades. Changes in spatial distribution of larvae occurred for 43% of taxa, with shifts predominately northward (i.e., along-shelf). Timing of larval occurrence shifted for 49% of the larval taxa, with shifts evenly split between occurring earlier and later in the season. Where both larvae and adults of the same species were analyzed, 48% exhibited different shifts between larval and adult stages. Overall, these results demonstrate that larval fish distributions are changing in the ecosystem. The spatial changes are largely consistent with expectations from a changing climate. The temporal changes are more complex, indicating we need a better understanding of reproductive timing of fishes in the ecosystem. These changes may impact population productivity through changes in life history connectivity and recruitment, and add to the accumulating evidence for changes in the Northeast U.S. Shelf Ecosystem with

  13. Long-Term Changes in the Distributions of Larval and Adult Fish in the Northeast U.S. Shelf Ecosystem.

    PubMed

    Walsh, Harvey J; Richardson, David E; Marancik, Katrin E; Hare, Jonathan A

    2015-01-01

    Many studies have documented long-term changes in adult marine fish distributions and linked these changes to climate change and multi-decadal climate variability. Most marine fish, however, have complex life histories with morphologically distinct stages, which use different habitats. Shifts in distribution of one stage may affect the connectivity between life stages and thereby impact population processes including spawning and recruitment. Specifically, many marine fish species have a planktonic larval stage, which lasts from weeks to months. We compared the spatial distribution and seasonal occurrence of larval fish in the Northeast U.S. Shelf Ecosystem to test whether spatial and temporal distributions changed between two decades. Two large-scale ichthyoplankton programs sampled using similar methods and spatial domain each decade. Adult distributions from a long-term bottom trawl survey over the same time period and spatial area were also analyzed using the same analytical framework to compare changes in larval and adult distributions between the two decades. Changes in spatial distribution of larvae occurred for 43% of taxa, with shifts predominately northward (i.e., along-shelf). Timing of larval occurrence shifted for 49% of the larval taxa, with shifts evenly split between occurring earlier and later in the season. Where both larvae and adults of the same species were analyzed, 48% exhibited different shifts between larval and adult stages. Overall, these results demonstrate that larval fish distributions are changing in the ecosystem. The spatial changes are largely consistent with expectations from a changing climate. The temporal changes are more complex, indicating we need a better understanding of reproductive timing of fishes in the ecosystem. These changes may impact population productivity through changes in life history connectivity and recruitment, and add to the accumulating evidence for changes in the Northeast U.S. Shelf Ecosystem with

  14. The Release Rate of Environmental DNA from Juvenile and Adult Fish

    PubMed Central

    Maruyama, Atsushi; Nakamura, Keisuke; Yamanaka, Hiroki; Kondoh, Michio; Minamoto, Toshifumi

    2014-01-01

    The environmental DNA (eDNA) technique is expected to become a powerful, non-invasive tool for estimating the distribution and biomass of organisms. This technique was recently shown to be applicable to aquatic vertebrates by collecting extraorganismal DNA floating in the water or absorbed onto suspended particles. However, basic information on eDNA release rate is lacking, despite it being essential for practical applications. In this series of experiments with bluegill sunfish (Lepomis macrochirus), we examined the effect of fish developmental stage on eDNA release rate. eDNA concentration reached equilibrium 3 days after the individual fish were introduced into the separate containers, enabling calculation of the eDNA release rate (copies h−1) from individual fish on the assumption that the number of eDNA released from the fish per unit time equals total degradation in the container (copies h−1). The eDNA release rate was 3–4 times higher in the adult (body weight: 30–75 g) than in the juvenile group (0.5–2.0 g). Such positive relationship between fish size and eDNA release rate support the possibility of biomass rather than density estimation using eDNA techniques. However, the eDNA release rate per fish body weight (copies h−1 g−1) was slightly higher in the juvenile than the adult group, which is likely because of the ontogenetic reduction in metabolic activity. Therefore, quantitative eDNA data should be carefully interpreted to avoid overestimating biomass when the population is dominated by juveniles, because the age structure of the focal population is often variable and unseen in the field. eDNA degradation rates (copies l−1 h−1), calculated by curve fitting of time-dependent changes in eDNA concentrations after fish removal, were 5.1–15.9% per hour (half-life: 6.3 h). This suggests that quantitative eDNA data should be corrected using a degradation curve attained in the target field. PMID:25479160

  15. Genetic concepts and uncertainties in restoring fish populations and species

    USGS Publications Warehouse

    Reisenbichler, R.R.; Utter, F.M.; Krueger, C.C.

    2003-01-01

    Genetic considerations can be crucially important to the success of reintroductions of lotic species. Current paradigms for conservation and population genetics provide guidance for reducing uncertainties in genetic issues and for increasing the likelihood of achieving restoration. Effective restoration is facilitated through specific goals and objectives developed from the definition that a restored or healthy population is (i) genetically adapted to the local environment, (ii) self-sustaining at abundances consistent with the carrying capacity of the river system, (iii) genetically compatible with neighboring populations so that substantial outbreeding depression does not result from straying and interbreeding between populations, and (iv) sufficiently diverse genetically to accommodate environmental variability over many decades. Genetic principles reveal the importance of describing and adhering to the ancestral lineages for the species to be restored and enabling genetic processes to maintain diversity and fitness in the populations under restoration. Newly established populations should be protected from unnecessary human sources of mortality, gene flow from maladapted (e.g., hatchery) or exotic populations, and inadvertent selection by fisheries or other human activities. Such protection facilitates initial, rapid adaptation of the population to its environment and should enhance the chances for persistence. Various uncertainties about specific restoration actions must be addressed on a case-by-case basis. Such uncertainties include whether to allow natural colonization or to introduce fish, which populations are suitable as sources for reintroduction, appropriate levels of gene flow from other populations, appropriate levels of artificial production, appropriate minimum numbers of individuals released or maintained in the population, and the best developmental stages for releasing fish into the restored stream. Rigorous evaluation or

  16. Evidence of population resistance to extreme low flows in a fluvial-dependent fish species

    USGS Publications Warehouse

    Katz, Rachel A.; Freeman, Mary C.

    2015-01-01

    Extreme low streamflows are natural disturbances to aquatic populations. Species in naturally intermittent streams display adaptations that enhance persistence during extreme events; however, the fate of populations in perennial streams during unprecedented low-flow periods is not well-understood. Biota requiring swift-flowing habitats may be especially vulnerable to flow reductions. We estimated the abundance and local survival of a native fluvial-dependent fish species (Etheostoma inscriptum) across 5 years encompassing historic low flows in a sixth-order southeastern USA perennial river. Based on capturemark-recapture data, the study shoal may have acted as a refuge during severe drought, with increased young-of-the-year (YOY) recruitment and occasionally high adult immigration. Contrary to expectations, summer and autumn survival rates (30 days) were not strongly depressed during low-flow periods, despite 25%-80% reductions in monthly discharge. Instead, YOY survival increased with lower minimum discharge and in response to small rain events that increased low-flow variability. Age-1+ fish showed the opposite pattern, with survival decreasing in response to increasing low-flow variability. Results from this population dynamics study of a small fish in a perennial river suggest that fluvial-dependent species can be resistant to extreme flow reductions through enhanced YOY recruitment and high survival

  17. Resistance to contaminants in North American fish populations.

    PubMed

    Wirgin, Isaac; Waldman, John R

    2004-08-18

    Fish from urban and industrialized estuaries are exposed among the highest levels of contaminants of any vertebrate populations. As a result, they serve as especially relevant models for determining the toxic effects and mechanisms through which environmental toxicants work. In controlled laboratory experiments, fish from highly contaminated locales sometimes exhibit resistance to contaminant-induced toxicity. Resistance may be due to genetic adaptation or physiological acclimations. Distinguishing between these possibilities is important in predicting the persistence of resistance and its potential costs to affected populations and communities. Along the Atlantic coast of North America, populations of two estuarine species, Atlantic killifish (mummichog) Fundulus heteroclitus and Atlantic tomcod Microgadus tomcod, exhibit phenotypes that are resistant to aromatic hydrocarbon (AH) contaminants, including polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polycyclic aromatic hydrocarbons (PAHs). Populations of these species exhibit resistance to AH-induced lethality, early life-stage toxicities, and expression of cytochrome P4501A (CYP1A). However, some differences among populations in the occurrence and type (genetic or physiological) of AH-resistant phenotypes have been observed. In some instances, resistance was obviously genetic and resulted in its transmission to at least the F2 generation, in others, resistance had a physiological or yet to be identified epigenetic basis. In some cases, resistance was observed for all AH compounds tested, in others, it was seen only for halogenated AHs. As toxic responses to AHs are believed to be mediated by the aryl hydrocarbon receptor pathway (AHR), several studies compared the structure and expression of AHR pathway molecules between resistant and sensitive fish populations. However, no obvious differences in these molecular parameters were observed between resistant and sensitive populations

  18. Life-history correlates of maximum population growth rates in marine fishes.

    PubMed Central

    Denney, Nicola H; Jennings, Simon; Reynolds, John D

    2002-01-01

    Theory predicts that populations of animals with late maturity, low fecundity, large body size and low body growth rates will have low potential rates of population increase at low abundance. If this is true, then these traits may be used to predict the intrinsic rate of increase for species or populations, as well as extinction risks. We used life-history and population data for 63 stocks of commercially exploited fish species from the northeast Atlantic to test relationships between life-history parameters and the rate of population increase at low abundance. We used cross-taxonomic analyses among stocks and among species, and analyses that accounted for phylogenetic relationships. These analyses confirmed that large-bodied, slow-growing stocks and species had significantly lower rates of recruitment and adult production per spawning adult at low abundance. Furthermore, high ages at maturity were significantly correlated with low maximum recruit production. Contrary to expectation, fecundity was significantly negatively related to recruit production, due to its positive relationship with maximum body size. Our results support theoretical predictions, and suggest that a simply measured life-history parameter can provide a useful tool for predicting rates of recovery from low population abundance. PMID:12427316

  19. Ocean acidification alters fish populations indirectly through habitat modification

    NASA Astrophysics Data System (ADS)

    Nagelkerken, Ivan; Russell, Bayden D.; Gillanders, Bronwyn M.; Connell, Sean D.

    2016-01-01

    Ocean ecosystems are predicted to lose biodiversity and productivity from increasing ocean acidification. Although laboratory experiments reveal negative effects of acidification on the behaviour and performance of species, more comprehensive predictions have been hampered by a lack of in situ studies that incorporate the complexity of interactions between species and their environment. We studied CO2 vents from both Northern and Southern hemispheres, using such natural laboratories to investigate the effect of ocean acidification on plant-animal associations embedded within all their natural complexity. Although we substantiate simple direct effects of reduced predator-avoidance behaviour by fishes, as observed in laboratory experiments, we here show that this negative effect is naturally dampened when fish reside in shelter-rich habitats. Importantly, elevated CO2 drove strong increases in the abundance of some fish species through major habitat shifts, associated increases in resources such as habitat and prey availability, and reduced predator abundances. The indirect effects of acidification via resource and predator alterations may have far-reaching consequences for population abundances, and its study provides a framework for a more comprehensive understanding of increasing CO2 emissions as a driver of ecological change.

  20. Evidence of Melanoma in Wild Marine Fish Populations

    PubMed Central

    Sweet, Michael; Kirkham, Nigel; Bendall, Mark; Currey, Leanne; Bythell, John; Heupel, Michelle

    2012-01-01

    The increase in reports of novel diseases in a wide range of ecosystems, both terrestrial and marine, has been linked to many factors including exposure to novel pathogens and changes in the global climate. Prevalence of skin cancer in particular has been found to be increasing in humans, but has not been reported in wild fish before. Here we report extensive melanosis and melanoma (skin cancer) in wild populations of an iconic, commercially-important marine fish, the coral trout Plectropomus leopardus. The syndrome reported here has strong similarities to previous studies associated with UV induced melanomas in the well-established laboratory fish model Xiphophorus. Relatively high prevalence rates of this syndrome (15%) were recorded at two offshore sites in the Great Barrier Reef Marine Park (GBRMP). In the absence of microbial pathogens and given the strong similarities to the UV-induced melanomas, we conclude that the likely cause was environmental exposure to UV radiation. Further studies are needed to establish the large scale distribution of the syndrome and confirm that the lesions reported here are the same as the melanoma in Xiphophorus, by assessing mutation of the EGFR gene, Xmrk. Furthermore, research on the potential links of this syndrome to increases in UV radiation from stratospheric ozone depletion needs to be completed. PMID:22870273

  1. Using Fish Population Metrics to Compare the Effects of Artificial Reef Density

    PubMed Central

    2015-01-01

    Artificial reefs continue to be added as habitat throughout the world, yet questions remain about how reef design affects fish diversity and abundance. In the present study, the effects of reef density were assessed for fish communities and sizes of economically valuable Lutjanus campechanus 13 km off Port Mansfield, Texas, at a reef composed of more than 4000 concrete culverts. The study spanned from May to June in 2013 and 2014, and sites sampled included natural reefs, bare areas, and varying culvert patch density categories, ranging from 1–190 culverts. Abundances of adults and species evenness of juvenile populations differed between the years. Fish communities did not significantly differ among density categories; however, highest species richness and total abundances were observed at intermediate culvert densities and at natural reefs. Whereas the abundance of L. campechanus did not differ among density categories, mean total lengths of L. campechanus were greatest at the lower density. Our findings suggest that reefs should be deployed with intermediate patch density of 71–120 culverts in a 30-m radius to yield the highest fish abundances. PMID:26422472

  2. Large scale, synchronous variability of marine fish populations driven by commercial exploitation

    PubMed Central

    Frank, Kenneth T.; Petrie, Brian; Leggett, William C.; Boyce, Daniel G.

    2016-01-01

    Synchronous variations in the abundance of geographically distinct marine fish populations are known to occur across spatial scales on the order of 1,000 km and greater. The prevailing assumption is that this large-scale coherent variability is a response to coupled atmosphere–ocean dynamics, commonly represented by climate indexes, such as the Atlantic Multidecadal Oscillation and North Atlantic Oscillation. On the other hand, it has been suggested that exploitation might contribute to this coherent variability. This possibility has been generally ignored or dismissed on the grounds that exploitation is unlikely to operate synchronously at such large spatial scales. Our analysis of adult fishing mortality and spawning stock biomass of 22 North Atlantic cod (Gadus morhua) stocks revealed that both the temporal and spatial scales in fishing mortality and spawning stock biomass were equivalent to those of the climate drivers. From these results, we conclude that greater consideration must be given to the potential of exploitation as a driving force behind broad, coherent variability of heavily exploited fish species. PMID:27382163

  3. Challenges in current adult fish laboratory reproductive tests: suggestions for refinement using a mummichog (Fundulus heteroclitus) case study.

    PubMed

    Bosker, Thijs; Munkittrick, Kelly R; MacLatchy, Deborah L

    2009-11-01

    Concerns about screening endocrine-active contaminants have led to the development of a number of short-term fish reproductive tests. A review conducted of 62 published adult fish reproductive papers using various fish species found low samples sizes (mean of 5.7 replicates with a median of 5 replicates) and high variance (an average coefficient of variance of 43.8%). The high variances and low sample sizes allow only relatively large differences to be detected with the current protocols; the average significant difference detected was a 68.7% reduction in egg production, while only differences above 50% were detected with confidence. This result indicates low power to detect more subtle differences and a high probability of type II errors in interpretation. The present study identifies several ways to increase the power of the adult fish reproductive test in the mummichog (Fundulus heteroclitus). By identifying the peak timing of egg production (before and after the new moon), extending the duration of the experiment (increased from 7 to 14 d), and determining that a sample size of eight replicate tanks per treatment accurately predicts variance in the sample population (based on pre-exposure variation calculations of replicate tanks), the power of the test has been significantly increased. The present study demonstrates that weaknesses in the current adult fish reproductive tests can easily be addressed by focusing on improved understanding of the reproductive behavior of the test species and developing study designs that include calculating desired variability levels and increasing replicates.

  4. Evaluation of Juvenile Fish Bypass and Adult Fish Passage Facilities at Water Diversions in the Umatilla River; 1993 Annual Report.

    SciTech Connect

    Knapp, Suzanne M.

    1994-03-01

    This report presents progress from October 1992 through September 1993 in evaluating juvenile fish bypass facilities at Three Mile Falls, Maxwell, Westland, and Feed Canal dams on the Umatilla River, and in evaluating adult fish passage in the lower Umatilla River. Also reported is an effort to evaluate delayed mortality and stress responses of juvenile salmonids resulting from trapping and transport at high temperatures. These studies are part of a program to rehabilitate anadromous fish stocks in the matilla River Basin, including restoration of coho salmon and chinook salmon, as well as enhancement of summer steelhead.

  5. Assessing population effects from entrainment of fish at a large volume water intake

    SciTech Connect

    Gray, R.H.; Page, T.L.; Neitzel, D.A.; Dauble, D.D.

    1986-01-01

    A method is described for estimating population effects from entrainment of juvenile chinook salmon (Oncorhynchus tshawytscha) at a steam electric generating station on the Columbia River that required cooperation between power plant operators and fishery biologists. The method involved sampling fish in the river and entrained fish (both marked recaptures and naturally occurring downstream migrants) within the intake, and estimating the 1) total number of fish entrained, 2) size of the natural population, and 3) percent of the natural population affected.

  6. Consumption dynamics of the adult piscivorous fish community in Spirit Lake, Iowa

    USGS Publications Warehouse

    Liao, H.; Pierce, C.L.; Larscheid, J.G.

    2004-01-01

    At Spirit Lake, one of Iowa's most important fisheries, walleye Sander vitreus (formerly Stizostedion vitreum) is one of the most popular species with anglers. Despite a century of walleye stocking and management in Spirit Lake, walleye growth rate, size structure, and angler harvest continue to decline. Our purpose was to determine the magnitude and dynamics of walleye population consumption relative to those of other piscivorous species in Spirit Lake, which would allow managers to judge the feasibility of increasing the abundance, growth rate, and size structure of the walleye population. We quantified food consumption by the adult piscivorous fish community in Spirit Lake over a 3-year period. Data on population dynamics, diet, energy density, and water temperature from 1995 to 1997 were used in bioenergetics models to estimate total consumption by walleye, yellow perch Perca flavescens, smallmouth bass Micropterus dolomieu, largemouth bass Micropterus salmoides, black crappie Pomoxis nigromaculatus, and northern pike Esox lucius. Estimated annual consumption by the piscivorous community varied roughly fourfold, ranging from 154,752 kg in 1995 to 662,776 kg in 1997. Walleyes dominated total consumption, accounting for 68, 73, and 90% (1995-1997, respectively) of total food consumption. Walleyes were also the dominant consumers of fish, accounting for 76, 86, and 97% of piscivorous consumption; yellow perch followed, accounting for 16% of piscivorous consumption in 1995 and 12% in 1996. Yellow perch were the predominant fish prey species in all 3 years, accounting for 68, 52, and 36% of the total prey consumed. Natural reproduction is weak, so high walleye densities are maintained by intensive stocking. Walleye stocking drives piscivorous consumption in Spirit Lake, and yearly variation in the cannibalism of stocked walleye fry may be an important determinant of walleye year-class strength and angler success. Reducing walleye stocking intensity, varying stocking

  7. Archaeological evidence of validity of fish populations on unexploited reefs as proxy targets for modern populations.

    PubMed

    Longenecker, Ken; Chan, Yvonne L; Toonen, Robert J; Carlon, David B; Hunt, Terry L; Friedlander, Alan M; Demartini, Edward E

    2014-10-01

    Reef-fish management and conservation is hindered by a lack of information on fish populations prior to large-scale contemporary human impacts. As a result, relatively pristine sites are often used as conservation baselines for populations near sites affected by humans. This space-for-time approach can only be validated by sampling assemblages through time. We used archaeological remains to evaluate whether the remote, uninhabited Northwestern Hawaiian Islands (NWHI) might provide a reasonable proxy for a lightly exploited baseline in the Main Hawaiian Islands (MHI). We used molecular and morphological techniques to describe the taxonomic and size composition of the scarine parrotfish catches present in 2 archaeological assemblages from the MHI, compared metrics of these catches with modern estimates of reproductive parameters to evaluate whether catches represented by the archaeological material were consistent with sustainable fishing, and evaluated overlap between size structures represented by the archaeological material and modern survey data from the MHI and the NWHI to assess whether a space-for-time substitution is reasonable. The parrotfish catches represented by archaeological remains were consistent with sustainable fishing because they were dominated by large, mature individuals whose average size remained stable from prehistoric (AD approximately 1400-1700) through historic (AD 1700-1960) periods. The ancient catches were unlike populations in the MHI today. Overlap between the size structure of ancient MHI catches and modern survey data from the NWHI or the MHI was an order of magnitude greater for the NWHI comparison, a result that supports the validity of using the NWHI parrotfish data as a proxy for the MHI before accelerated, heavy human impacts in modern times.

  8. Modeling future acidification and fish populations in Norwegian surface waters.

    PubMed

    Larssen, Thorjørn; Cosby, Bernard J; Lund, Espen; Wright, Richard F

    2010-07-15

    Despite great progress made in the past 25 years, acid deposition continues to cause widespread damage to the environment in Europe and eastern North America. Legislation to limit emissions of sulfur and nitrogen compounds in Europe is now under revision. The most recent protocol was based in part on the critical loads concept. The new protocol may also take into consideration the time delays between dose and response inherent in natural ecosystems. Policy decisions to reduce adverse effects on ecosystems entail a trade-off: quick response will require deeper cuts in emissions and thus higher costs, whereas lower costs with lesser cuts in emissions will give slower response. Acidification of lakes and damage to fish populations in Norway is used as an example. Under current legislation for emission reductions, surface waters will continue to slowly recover, but for many decades lakes in about 18% of Norway will continue to have water quality insufficient to support healthy populations of brown trout and other indicator organisms. Additional emission reductions can speed up the rate and degree of recovery.

  9. Subtle genetic structure reveals restricted connectivity among populations of a coral reef fish inhabiting remote atolls

    PubMed Central

    Underwood, Jim N; Travers, Michael J; Gilmour, James P

    2012-01-01

    We utilized a spatial and temporal analyses of genetic structure, supplemented with ecological and oceanographic analysis, to assess patterns of population connectivity in a coral reef fish Chromis margaritifer among the unique and remote atolls in the eastern Indian Ocean. A subtle, but significant genetic discontinuity at 10 microsatellite DNA loci was detected between atoll systems corresponding with a low (≤ 1%) probability of advection across the hundreds of kilometers of open ocean that separates them. Thus, although genetic connections between systems are likely maintained by occasional long-distance dispersal of C. margaritifer larvae, ecological population connectivity at this spatial scale appears to be restricted. Further, within one of these atoll systems, significant spatial differentiation among samples was accompanied by a lack of temporal pairwise differentiation between recruit and adult samples, indicating that restrictions to connectivity also occur at a local scale (tens of kilometers). In contrast, a signal of panmixia was detected at the other atoll system studied. Lastly, greater relatedness and reduced genetic diversity within recruit samples was associated with relatively large differences among them, indicating the presence of sweepstakes reproduction whereby a small proportion of adults contributes to recruitment in the next generation. These results are congruent with earlier work on hard corals, suggesting that local production of larvae drives population replenishment in these atoll systems for a range of coral reef species. PMID:22822442

  10. Subtle genetic structure reveals restricted connectivity among populations of a coral reef fish inhabiting remote atolls.

    PubMed

    Underwood, Jim N; Travers, Michael J; Gilmour, James P

    2012-03-01

    We utilized a spatial and temporal analyses of genetic structure, supplemented with ecological and oceanographic analysis, to assess patterns of population connectivity in a coral reef fish Chromis margaritifer among the unique and remote atolls in the eastern Indian Ocean. A subtle, but significant genetic discontinuity at 10 microsatellite DNA loci was detected between atoll systems corresponding with a low (≤ 1%) probability of advection across the hundreds of kilometers of open ocean that separates them. Thus, although genetic connections between systems are likely maintained by occasional long-distance dispersal of C. margaritifer larvae, ecological population connectivity at this spatial scale appears to be restricted. Further, within one of these atoll systems, significant spatial differentiation among samples was accompanied by a lack of temporal pairwise differentiation between recruit and adult samples, indicating that restrictions to connectivity also occur at a local scale (tens of kilometers). In contrast, a signal of panmixia was detected at the other atoll system studied. Lastly, greater relatedness and reduced genetic diversity within recruit samples was associated with relatively large differences among them, indicating the presence of sweepstakes reproduction whereby a small proportion of adults contributes to recruitment in the next generation. These results are congruent with earlier work on hard corals, suggesting that local production of larvae drives population replenishment in these atoll systems for a range of coral reef species.

  11. CHARACTERIZING POPULATIONS OF THE ESTUARINE FISH FUNDULUS HETEROCLITUS INDIGENOUS TO SITES WITH DIFFERING ENVIRONMENTAL QUALITY

    EPA Science Inventory

    Populations of the non-migratory estuarine fish Fundulus heteroclitus were collected from New Bedford Harbor and distant clean sites to investigate whether indigenous populations have adapted genetically to the harbor's contamination. New Bedford Harbor, a major port in southe...

  12. Fish consumption pattern among adults of different ethnics in Peninsular Malaysia

    PubMed Central

    Ahmad, Nurul Izzah; Wan Mahiyuddin, Wan Rozita; Tengku Mohamad, Tengku Rozaina; Ling, Cheong Yoon; Daud, Siti Fatimah; Hussein, Nasriyah Che; Abdullah, Nor Aini; Shaharudin, Rafiza; Sulaiman, Lokman Hakim

    2016-01-01

    Background Understanding different patterns of fish consumption is an important component for risk assessment of contaminants in fish. A few studies on food consumption had been conducted in Malaysia, but none of them focused specifically on fish consumption. The objectives of this study were to document the meal pattern among three major ethnics in Malaysia with respect to fish/seafood consumption, identify most frequently consumed fish and cooking method, and examine the influence of demographic factors on pattern of fish consumption among study subjects. Methods A cross-sectional survey was conducted between February 2008 and May 2009 to investigate patterns of fish consumption among Malaysian adults in Peninsular Malaysia. Adults aged 18 years and above were randomly selected and fish consumption data were collected using a 3-day prospective food diary. Results A total of 2,675 subjects, comprising male (44.2%) and female (55.7%) participants from major ethnics (Malays, 76.9%; Chinese, 14.7%; Indians, 8.3%) with a mean age of 43.4±16.2 years, were involved in this study. The results revealed 10 most frequently consumed marine fish in descending order: Indian mackerel, anchovy, yellowtail and yellow-stripe scads, tuna, sardines, torpedo scad, Indian and short-fin scads, pomfret, red snapper, and king mackerel. Prawn and squid were also among the most preferred seafood by study subjects. The most frequently consumed freshwater fish were freshwater catfish and snakehead. The most preferred cooking style by Malaysians was deep-fried fish, followed by fish cooked in thick and/or thin chili gravy, fish curry, and fish cooked with coconut milk mixed with other spices and flavorings. Overall, Malaysians consumed 168 g/day fish, with Malay ethnics’ (175±143 g/day) consumption of fish significantly (p<0.001) higher compared with the other two ethnic groups (Chinese=152±133 g/day, Indians=136±141 g/day). Conclusion Fish consumption was significantly associated with

  13. Savannah River Aquatic Ecology Program. Volume I. Adult fish. Annual report, November 1983-August 1984

    SciTech Connect

    Paller, M.; Osteen, D.V.

    1985-05-01

    A multipurpose study on the fish community of the Savannah River near the Savannah River Plant was conducted between September 1983 and August 1984. The major portion of this study examined the abundance and distribution of fishes near the Savannah River Plant in relation to the thermal discharges into the river, creeks and the floodplain swamp. Another portion of the study examined the rates of impingement of juvenile and adult fishes onto the river water intake screens in order to assess the potential influence of this plant operation on the fish community. 24 refs., 13 figs., 23 tabs.

  14. The invariance of production per unit of food consumed in fish populations.

    PubMed

    Wiff, R; Barrientos, M A; Segura, A M; Milessi, A C

    2017-02-03

    The amount of biomass production per unit of food consumed (P/Q) represents an important quantity in ecosystem functioning, because it indicates how efficient a population transforms ingested food into biomass. Several investigations have noticed that P/Q remains relatively constant (or invariant) across fish population that feed at the same food-type level (carnivorous/herbivorous). Nevertheless, theoretical explanation for this invariant is still lacking. In this paper, we demonstrate that P/Q remains invariant across fish populations with stable-age distribution. Three key assumptions underpin the P/Q invariant: (1) the ratio between natural mortality M and von Bertalanffy growth parameter k (M/k ratio) should remain invariant across fish populations; (2) a parameter defining the fraction of ingested food available for growth needs to remain constant across fish that feed at the same trophic level; (3) third, the ratio between length at age 0 ([Formula: see text]) and asymptotic length ([Formula: see text]) should be constant across fish populations. The influence of these assumptions on the P/Q estimates were numerically assessed considering fish populations of different lifespan. Numerical evaluations show that the most critical condition highly relates to the first assumption, M/k. Results are discussed in the context of the reliability of the required assumption to consider the P/Q invariant in stable-age distributed fish populations.

  15. Restoring depleted coral-reef fish populations through recruitment enhancement: a proof of concept.

    PubMed

    Heenan, A; Simpson, S D; Meekan, M G; Healy, S D; Braithwaite, V A

    2009-11-01

    To determine whether enhancing the survival of new recruits is a sensible target for the restorative management of depleted coral-reef fish populations, settlement-stage ambon damsel fish Pomacentrus amboinensis were captured, tagged and then either released immediately onto small artificial reefs or held in aquaria for 1 week prior to release. Holding conditions were varied to determine whether they affected survival of fish: half the fish were held in bare tanks (non-enriched) and the other half in tanks containing coral and sand (enriched). Holding fish for this short period had a significantly positive effect on survivorship relative to the settlement-stage treatment group that were released immediately. The enrichment of holding conditions made no appreciable difference on the survival of fish once released onto the reef. It did, however, have a positive effect on the survival of fish while in captivity, thus supporting the case for the provision of simple environmental enrichment in fish husbandry. Collecting and holding settlement-stage fish for at least a week before release appear to increase the short-term survival of released fish; whether it is an effective method for longer-term enhancement of locally depleted coral-reef fish populations will require further study.

  16. High site fidelity and low site connectivity in temperate salt marsh fish populations: a stable isotope approach.

    PubMed

    Green, Benjamin C; Smith, David J; Grey, Jonathan; Underwood, Graham J C

    2012-01-01

    Adult and juvenile fish utilise salt marshes for food and shelter at high tide, moving into adjacent sublittoral regions during low tide. Understanding whether there are high levels of site fidelity for different species of coastal fish has important implications for habitat conservation and the design of marine protected areas. We hypothesised that common salt marsh fish species would demonstrate a high site fidelity, resulting in minimal inter-marsh connectivity. Carbon ((13)C) and nitrogen ((15)N) stable isotope ratios of larvae and juveniles of five common salt marsh fish (Atherina presbyter, Chelon labrosus, Clupea harengus, Dicentrarchus labrax, Pomatoschistus microps), seven types of primary producer and seven secondary consumer food sources were sampled in five salt marshes within two estuary complexes along the coast of south-east England. Significant differences in (13)C and (15)N signatures between salt marshes indicated distinct sub-populations utilising the area of estuary around each salt marsh, and limited connectivity, even within the same estuary complex. (15)N ratios were responsible for the majority of inter-marsh differences for each species and showed similar site-specific patterns in ratios in primary producers, secondary consumers and fish. Fish diets (derived from isotope mixing models) varied between species but were mostly consistent between marsh sites, indicating that dietary shifts were not the source of variability of the inter-marsh isotopic signatures within species. These results demonstrate that for some common coastal fish species, high levels of site fidelity result in individual salt marshes operating as discrete habitats for fish assemblages.

  17. Management of fish populations in large rivers: a review of tools and approaches

    USGS Publications Warehouse

    Petts, Geoffrey E.; Imhoff, Jack G.; Manny, Bruce A.; Maher, John F. B.; Weisberg, Stephen B.

    1989-01-01

    In common with most branches of science, the management of riverine fish populations is characterised by reductionist and isolationist philosophies. Traditional fish management focuses on stocking and controls on fishing. This paper presents a concensus of scientists involved in the LARS workshop on the management of fish populations in large rivers. A move towards a more holistic philosophy is advocated, with fish management forming an integral part of sustainable river development. Based upon a questionnaire survey of LARS members, with wide-ranging expertise and experience from all parts of the world, lists of management tools currently in use are presented. Four categories of tools are described: flow, water-quality, habitat, and biological. The potential applications of tools for fish management in large rivers is discussed and research needs are identified. The lack of scientific evaluations of the different tools remains the major constraint to their wider application.

  18. MODELING THE RESPONSE OF FISH POPULATIONS TO EUTROPHICATION

    EPA Science Inventory

    Eutrophication resulting from nonpoint source pollution is one of the largest environmental problems in lakes and reservoirs around the world. Two characteristics of eutrophication, decreased dissolved oxygen and increased concentration of ammonia, are known to affect fishes, yet...

  19. Climate change effects on North American inland fish populations and assemblages

    USGS Publications Warehouse

    Lynch, Abigail J.; Myers, Bonnie; Chu, Cindy; Eby, Lisa A.; Falke, Jeffrey A.; Kovach, Ryan P.; Krabbenhoft, Trevor J.; Kwak, Thomas J.; Lyons, John; Paukert, Craig P.; Whitney, James E.

    2016-01-01

    Climate is a critical driver of many fish populations, assemblages, and aquatic communities. However, direct observational studies of climate change impacts on North American inland fishes are rare. In this synthesis, we (1) summarize climate trends that may influence North American inland fish populations and assemblages, (2) compile 31 peer-reviewed studies of documented climate change effects on North American inland fish populations and assemblages, and (3) highlight four case studies representing a variety of observed responses ranging from warmwater systems in the southwestern and southeastern United States to coldwater systems along the Pacific Coast and Canadian Shield. We conclude by identifying key data gaps and research needs to inform adaptive, ecosystem-based approaches to managing North American inland fishes and fisheries in a changing climate.

  20. First genealogy for a wild marine fish population reveals multigenerational philopatry

    PubMed Central

    Salles, Océane C.; Pujol, Benoit; Maynard, Jeffrey A.; Almany, Glenn R.; Berumen, Michael L.; Jones, Geoffrey P.; Saenz-Agudelo, Pablo; Srinivasan, Maya; Thorrold, Simon R.; Planes, Serge

    2016-01-01

    Natal philopatry, the return of individuals to their natal area for reproduction, has advantages and disadvantages for animal populations. Natal philopatry may generate local genetic adaptation, but it may also increase the probability of inbreeding that can compromise persistence. Although natal philopatry is well documented in anadromous fishes, marine fish may also return to their birth site to spawn. How philopatry shapes wild fish populations is, however, unclear because it requires constructing multigenerational pedigrees that are currently lacking for marine fishes. Here we present the first multigenerational pedigree for a marine fish population by repeatedly genotyping all individuals in a population of the orange clownfish (Amphiprion percula) at Kimbe Island (Papua New Guinea) during a 10-y period. Based on 2927 individuals, our pedigree analysis revealed that longitudinal philopatry was recurrent over five generations. Progeny tended to settle close to their parents, with related individuals often sharing the same colony. However, successful inbreeding was rare, and genetic diversity remained high, suggesting occasional inbreeding does not impair local population persistence. Local reproductive success was dependent on the habitat larvae settled into, rather than the habitat they came from. Our study suggests that longitudinal philopatry can influence both population replenishment and local adaptation of marine fishes. Resolving multigenerational pedigrees during a relatively short period, as we present here, provides a framework for assessing the ability of marine populations to persist and adapt to accelerating climate change. PMID:27799530

  1. Estimating Consumption to Biomass Ratio in Non-Stationary Harvested Fish Populations

    PubMed Central

    Wiff, Rodrigo; Roa-Ureta, Ruben H.; Borchers, David L.; Milessi, Andrés C.; Barrientos, Mauricio A.

    2015-01-01

    The food consumption to biomass ratio (C) is one of the most important population parameters in ecosystem modelling because its quantifies the interactions between predator and prey. Existing models for estimating C in fish populations are per-recruit cohort models or empirical models, valid only for stationary populations. Moreover, empirical models lack theoretical support. Here we develop a theory and derive a general modelling framework to estimate C in fish populations, based on length frequency data and the generalised von Bertalanffy growth function, in which models for stationary populations with a stable-age distributions are special cases. Estimates using our method are compared with estimates from per-recruit cohort models for C using simulated harvested fish populations of different lifespans. The models proposed here are also applied to three fish populations that are targets of commercial fisheries in southern Chile. Uncertainty in the estimation of C was evaluated using a resampling approach. Simulations showed that stationary and non-stationary population models produce different estimates for C and those differences depend on the lifespan, fishing mortality and recruitment variations. Estimates of C using the new model exhibited smoother inter-annual variation in comparison with a per-recruit model estimates and they were also smaller than C predicted by the empirical equations in all population assessed. PMID:26528721

  2. Electric fish: new insights into conserved processes of adult tissue regeneration.

    PubMed

    Unguez, Graciela A

    2013-07-01

    Biology is replete with examples of regeneration, the process that allows animals to replace or repair cells, tissues and organs. As on land, vertebrates in aquatic environments experience the occurrence of injury with varying frequency and to different degrees. Studies demonstrate that ray-finned fishes possess a very high capacity to regenerate different tissues and organs when they are adults. Among fishes that exhibit robust regenerative capacities are the neotropical electric fishes of South America (Teleostei: Gymnotiformes). Specifically, adult gymnotiform electric fishes can regenerate injured brain and spinal cord tissues and restore amputated body parts repeatedly. We have begun to identify some aspects of the cellular and molecular mechanisms of tail regeneration in the weakly electric fish Sternopygus macrurus (long-tailed knifefish) with a focus on regeneration of skeletal muscle and the muscle-derived electric organ. Application of in vivo microinjection techniques and generation of myogenic stem cell markers are beginning to overcome some of the challenges owing to the limitations of working with non-genetic animal models with extensive regenerative capacity. This review highlights some aspects of tail regeneration in S. macrurus and discusses the advantages of using gymnotiform electric fishes to investigate the cellular and molecular mechanisms that produce new cells during regeneration in adult vertebrates.

  3. Electric fish: new insights into conserved processes of adult tissue regeneration

    PubMed Central

    Unguez, Graciela A.

    2013-01-01

    Summary Biology is replete with examples of regeneration, the process that allows animals to replace or repair cells, tissues and organs. As on land, vertebrates in aquatic environments experience the occurrence of injury with varying frequency and to different degrees. Studies demonstrate that ray-finned fishes possess a very high capacity to regenerate different tissues and organs when they are adults. Among fishes that exhibit robust regenerative capacities are the neotropical electric fishes of South America (Teleostei: Gymnotiformes). Specifically, adult gymnotiform electric fishes can regenerate injured brain and spinal cord tissues and restore amputated body parts repeatedly. We have begun to identify some aspects of the cellular and molecular mechanisms of tail regeneration in the weakly electric fish Sternopygus macrurus (long-tailed knifefish) with a focus on regeneration of skeletal muscle and the muscle-derived electric organ. Application of in vivo microinjection techniques and generation of myogenic stem cell markers are beginning to overcome some of the challenges owing to the limitations of working with non-genetic animal models with extensive regenerative capacity. This review highlights some aspects of tail regeneration in S. macrurus and discusses the advantages of using gymnotiform electric fishes to investigate the cellular and molecular mechanisms that produce new cells during regeneration in adult vertebrates. PMID:23761473

  4. Using passive acoustic telemetry to infer mortality events in adult herbivorous coral reef fishes

    NASA Astrophysics Data System (ADS)

    Khan, J. A.; Welsh, J. Q.; Bellwood, D. R.

    2016-06-01

    Mortality is considered to be an important factor shaping the structure of coral reef fish communities, but data on the rate and nature of mortality of adult coral reef fishes are sparse. Mortality on coral reefs is intrinsically linked with predation, with most evidence suggesting that predation is highest during crepuscular periods. We tested this hypothesis using passive acoustic telemetry data to determine the time of day of potential mortality events (PMEs) of adult herbivorous reef fishes. A total of 94 fishes were tagged with acoustic transmitters, of which 43 exhibited a PME. Furthermore, we identified five categories of PMEs based on the nature of change in acoustic signal detections from tagged fishes. The majority of PMEs were characterised by an abrupt stop in detections, possibly as a result of a large, mobile predator. Overall, mortality rates were estimated to be approximately 59 % per year using passive acoustic telemetry. The time of day of PMEs suggests that predation was highest during the day and crepuscular periods and lowest at night, offering only partial support for the crepuscular predation hypothesis. Visually oriented, diurnal and crepuscular predators appear to be more important than their nocturnal counterparts in terms of predation on adult reef fishes. By timing PMEs, passive acoustic telemetry may offer an important new tool for investigating the nature of predation on coral reefs.

  5. Population-specific consequences of fisheries-related stressors on adult sockeye salmon.

    PubMed

    Donaldson, M R; Hinch, S G; Raby, G D; Patterson, D A; Farrell, A P; Cooke, S J

    2012-01-01

    The objective of this study was to determine whether fisheries-related stressors differently influence two populations of adult sockeye salmon (Oncorhynchus nerka) with shared migration timing and location but where one population (i.e., Harrison) spawns 1 mo after the other (i.e., Weaver). Four stressor treatments were used following beach seine capture: (1) immediate release, (2) release after 10-15 min in the beach seine, (3) an additional 3-min gill net entanglement and 1-min air exposure, and (4) an additional 3-min tangle net simulation and 1-min air exposure. A comprehensive acoustic telemetry array and manual tracking revealed that survival was low overall, with more Weaver fish (34.2% of 38 tagged) reaching spawning areas compared to Harrison fish (17.8% of 78 tagged). For the Harrison population but not the Weaver, the gill net treatment influenced immediate (i.e., survived treatment) and short-term (i.e., 5-d postrelease) survival as well as survival to reach spawning areas. Harrison fish were more likely to be injured by the treatment, and reflex impairment predicted their short-term and long-term survival. Physiological condition did not differ between populations at the time of release, although both populations showed signs of severe physiological disturbances from the gill and tangle net simulations. These results suggest that even short durations of gill or tangle net entanglement can result in profound population-specific physiological disturbances and mortality. The notion that there can be population-specific variation in response to fisheries encounters adds complexity to management and provides further evidence for intraspecific differences in migration success.

  6. Population Variation in the Life History of a Land Fish, Alticus arnoldorum, and the Effects of Predation and Density

    PubMed Central

    Platt, Edward R. M.; Ord, Terry J.

    2015-01-01

    Life history variation can often reflect differences in age-specific mortality within populations, with the general expectation that reproduction should be shifted away from ages experiencing increased mortality. Investigators of life history in vertebrates frequently focus on the impact of predation, but there is increasing evidence that predation may have unexpected impacts on population density that in turn prompt unexpected changes in life history. There are also other reasons why density might impact life history independently of predation or mortality more generally. We investigated the consequences of predation and density on life history variation among populations of the Pacific leaping blenny, Alticus arnoldorum. This fish from the island of Guam spends its adult life out of the water on rocks in the splash zone, where it is vulnerable to predation and can be expected to be sensitive to changes in population density that impact resource availability. We found populations invested more in reproduction as predation decreased, while growth rate varied primarily in response to population density. These differences in life history among populations are likely plastic given the extensive gene flow among populations revealed by a previous study. The influence of predation and density on life history was unlikely to have operated independently of each other, with predation rate tending to be associated with reduced population densities. Taken together, our results suggest predation and density can have complex influences on life history, and that plastic life history traits could allow populations to persist in new or rapidly changing environments. PMID:26398191

  7. Population Variation in the Life History of a Land Fish, Alticus arnoldorum, and the Effects of Predation and Density.

    PubMed

    Platt, Edward R M; Ord, Terry J

    2015-01-01

    Life history variation can often reflect differences in age-specific mortality within populations, with the general expectation that reproduction should be shifted away from ages experiencing increased mortality. Investigators of life history in vertebrates frequently focus on the impact of predation, but there is increasing evidence that predation may have unexpected impacts on population density that in turn prompt unexpected changes in life history. There are also other reasons why density might impact life history independently of predation or mortality more generally. We investigated the consequences of predation and density on life history variation among populations of the Pacific leaping blenny, Alticus arnoldorum. This fish from the island of Guam spends its adult life out of the water on rocks in the splash zone, where it is vulnerable to predation and can be expected to be sensitive to changes in population density that impact resource availability. We found populations invested more in reproduction as predation decreased, while growth rate varied primarily in response to population density. These differences in life history among populations are likely plastic given the extensive gene flow among populations revealed by a previous study. The influence of predation and density on life history was unlikely to have operated independently of each other, with predation rate tending to be associated with reduced population densities. Taken together, our results suggest predation and density can have complex influences on life history, and that plastic life history traits could allow populations to persist in new or rapidly changing environments.

  8. Sublethal exposure to crude oil during embryonic development alters cardiac morphology and reduces aerobic capacity in adult fish

    PubMed Central

    Hicken, Corinne E.; Linbo, Tiffany L.; Baldwin, David H.; Willis, Maryjean L.; Myers, Mark S.; Holland, Larry; Larsen, Marie; Stekoll, Michael S.; Rice, Stanley D.; Collier, Tracy K.; Scholz, Nathaniel L.; Incardona, John P.

    2011-01-01

    Exposure to high concentrations of crude oil produces a lethal syndrome of heart failure in fish embryos. Mortality is caused by cardiotoxic polycyclic aromatic hydrocarbons (PAHs), ubiquitous components of petroleum. Here, we show that transient embryonic exposure to very low concentrations of oil causes toxicity that is sublethal, delayed, and not counteracted by the protective effects of cytochrome P450 induction. Nearly a year after embryonic oil exposure, adult zebrafish showed subtle changes in heart shape and a significant reduction in swimming performance, indicative of reduced cardiac output. These delayed physiological impacts on cardiovascular performance at later life stages provide a potential mechanism linking reduced individual survival to population-level ecosystem responses of fish species to chronic, low-level oil pollution. PMID:21482755

  9. Nocturnal relocation of adult and juvenile coral reef fishes in response to reef noise

    NASA Astrophysics Data System (ADS)

    Simpson, S. D.; Jeffs, A.; Montgomery, J. C.; McCauley, R. D.; Meekan, M. G.

    2008-03-01

    Juvenile and adult reef fishes often undergo migration, ontogenic habitat shifts, and nocturnal foraging movements. The orientation cues used for these behaviours are largely unknown. In this study, the use of sound as an orientation cue guiding the nocturnal movements of adult and juvenile reef fishes at Lizard Island, Great Barrier Reef was examined. The first experiment compared the movements of fishes to small patch reefs where reef noise was broadcast, with those to silent reefs. No significant responses were found in the 79 adults that were collected, but the 166 juveniles collected showed an increased diversity each morning on the reefs with broadcast noise, and significantly greater numbers of juveniles from three taxa (Apogonidae, Gobiidae and Pinguipedidae) were collected from reefs with broadcast noise. The second experiment compared the movement of adult and juvenile fishes to reefs broadcasting high (>570 Hz), or low (<570 Hz) frequency reef noise, or to silent reefs. Of the 122 adults collected, the highest diversity was seen at the low frequency reefs; and adults from two families (Gobiidae and Blenniidae) preferred these reefs. A similar trend was observed in the 372 juveniles collected, with higher diversity at the reefs with low frequency noises. This preference was seen in the juvenile apogonids; however, juvenile gobiids were attracted to both high and low sound treatments equally, and juvenile stage Acanthuridae preferred the high frequency noises. This evidence that juvenile and adult reef fishes orientate with respect to the soundscape raises important issues for management, conservation and the protection of sound cues used in natural behaviour.

  10. Effects of stream acidification and habitat on fish populations of a North American river

    USGS Publications Warehouse

    Baldigo, Barry P.; Lawrence, G.B.

    2001-01-01

    Water quality, physical habitat, and fisheries at sixteen reaches in the Neversink River Basin were studied during 1991-95 to identify the effects of acidic precipitation on stream-water chemistry and on selected fish-species populations, and to test the hypothesis that the degree of stream acidification affected the spatial distribution of each fish-species population. Most sites on the East Branch Neversink were strongly to severely acidified, whereas most sites on the West Branch were minimally to moderately acidified. Mean density of fish populations ranged from 0 to 2.15 fish/m2; biomass ranged from 0 to 17.5 g/m2. Where brook trout were present, their population density ranged from 0.04 to 1.09 fish/m2, biomass ranged from 0.76 to 12.2 g/m2, and condition (K) ranged from 0.94 to 1.07. Regression analyses revealed strong relations (r2 ?? 0.41 to 0.99; p ??? 0.05) between characteristics of the two most common species (brook trout and slimy sculpin) populations and mean concentrations of inorganic monomeric aluminum (Alim), pH, Si, K+, NO3/-, NH4/+, DOC, Ca2+, and Na+; acid neutralizing capacity (ANC); and water temperature. Stream acidification may have adversely affected fish populations at most East Branch sites, but in other parts of the Neversink River Basin these effects were masked or mitigated by other physical habitat, geochemical, and biological factors.

  11. Vulnerability and diet breadth predict larval and adult parasite diversity in fish of the Bothnian Bay.

    PubMed

    Locke, Sean A; Marcogliese, David J; Valtonen, E Tellervo

    2014-01-01

    Recent studies of aquatic food webs show that parasite diversity is concentrated in nodes that likely favour transmission. Various aspects of parasite diversity have been observed to be correlated with the trophic level, size, diet breadth, and vulnerability to predation of hosts. However, no study has attempted to distinguish among all four correlates, which may have differential importance for trophically transmitted parasites occurring as larvae or adults. We searched for factors that best predict the diversity of larval and adult endoparasites in 4105 fish in 25 species studied over a three-year period in the Bothnian Bay, Finland. Local predator-prey relationships were determined from stomach contents, parasites, and published data in 8,229 fish in 31 species and in seals and piscivorous birds. Fish that consumed more species of prey had more diverse trophically transmitted adult parasites. Larval parasite diversity increased with the diversity of both prey and predators, but increases in predator diversity had a greater effect. Prey diversity was more strongly associated with the diversity of adult parasites than with that of larvae. The proportion of parasite species present as larvae in a host species was correlated with the diversity of its predators. There was a notable lack of association with the diversity of any parasite guild and fish length, trophic level, or trophic category. Thus, diversity is associated with different nodal properties in larval and adult parasites, and association strengths also differ, strongly reflecting the life cycles of parasites and the food chains they follow to complete transmission.

  12. Evaluation of Juvenile Fish Bypass and Adult Fish Passage Facilities at Water Diversions on the Umatilla River; 1994 Annual Report.

    SciTech Connect

    Knapp, Suzanne M.

    1995-01-01

    We report on our progress from October 1993 through September 1994 in evaluating juvenile salmonid bypass facilities and juvenile salmonid passage through ladder facilities, and investigating passage conditions for juvenile fish at diversion dam facilities on the lower Umatilla River in northeastern Oregon. We also report on our progress in evaluating adult salmonid passage at and between dams on the lower Umatilla River and upriver migration using radio telemetry. Two principal studies are also included. Report A (ODFW): To evaluate the juvenile salmonid bypass facilities a Feed and Furnish canals, juvenile salmonid passage through fish ladders at Stanfield, Feed Canal, Westland, and Three Mile Falls dams, and the juvenile salmonid trap and haul procedures at Westland Canal. To investigate passage conditions at all passage facilities. Report B (CTUIR): To examine the passage of adult salmonids past diversions in the lower Umatilla River and their movement in the upper river after transport, using radio telemetry, and to assess factors for successful homing. These studies are part of a program to rehabilitate anadromous fish stocks in the Umatilla River Basin, including restoration of coho salmon (Oncorhynchus kisutch) and chinook salmon (Oncorhynchus tshawytscha), as well as enhancement of summer steelhead (Oncorhynchus mykiss).

  13. Population maintenance among tropical reef fishes: Inferences from small-island endemics

    PubMed Central

    Robertson, D. Ross

    2001-01-01

    To what extent do local populations of tropical reef fishes persist through the recruitment of pelagic larvae to their natal reef? Endemics from small, isolated islands can help answer that question by indicating whether special biological attributes are needed for long-term survival under enforced localization in high-risk situations. Taxonomically and biologically, the endemics from seven such islands are broadly representative of their regional faunas. As natal-site recruitment occurs among reef fishes in much less isolated situations, these characteristics of island endemics indicate that a wide range of reef fishes could have persistent self-sustaining local populations. Because small islands regularly support substantial reef fish faunas, regional systems of small reserves could preserve much of the diversity of these fishes. PMID:11331752

  14. STREAM FISH HABITAT SUITABILITY AND THE RISK OF POPULATION DECLINE

    EPA Science Inventory

    Over half of the streams in the Mid-Atlantic Highlands have fish communities that are in fair or poor condition, and the EPA concluded that physical habitat alteration represents the greatest potential stressor across this region. A quantitative method for relating habitat quali...

  15. Sampling characteristics and calibration of snorkel counts to estimate stream fish populations

    USGS Publications Warehouse

    Weaver, D.; Kwak, Thomas J.; Pollock, Kenneth

    2014-01-01

    Snorkeling is a versatile technique for estimating lotic fish population characteristics; however, few investigators have evaluated its accuracy at population or assemblage levels. We evaluated the accuracy of snorkeling using prepositioned areal electrofishing (PAE) for estimating fish populations in a medium-sized Appalachian Mountain river during fall 2008 and summer 2009. Strip-transect snorkel counts were calibrated with PAE counts in identical locations among macrohabitats, fish species or taxa, and seasons. Mean snorkeling efficiency (i.e., the proportion of individuals counted from the true population) among all taxa and seasons was 14.7% (SE, 2.5%), and the highest efficiencies were for River Chub Nocomis micropogon at 21.1% (SE, 5.9%), Central Stoneroller Campostoma anomalum at 20.3% (SE, 9.6%), and darters (Percidae) at 17.1% (SE, 3.7%), whereas efficiencies were lower for shiners (Notropis spp., Cyprinella spp., Luxilus spp.) at 8.2% (SE, 2.2%) and suckers (Catostomidae) at 6.6% (SE, 3.2%). Macrohabitat type, fish taxon, or sampling season did not significantly explain variance in snorkeling efficiency. Mean snorkeling detection probability (i.e., probability of detecting at least one individual of a taxon) among fish taxa and seasons was 58.4% (SE, 6.1%). We applied the efficiencies from our calibration study to adjust snorkel counts from an intensive snorkeling survey conducted in a nearby reach. Total fish density estimates from strip-transect counts adjusted for snorkeling efficiency were 7,288 fish/ha (SE, 1,564) during summer and 15,805 fish/ha (SE, 4,947) during fall. Precision of fish density estimates is influenced by variation in snorkeling efficiency and sample size and may be increased with additional sampling effort. These results demonstrate the sampling properties and utility of snorkeling to characterize lotic fish assemblages with acceptable efficiency and detection probability, less effort, and no mortality, compared with traditional

  16. Successful treatment of parenteral nutrition-associated liver disease in an adult by use of a fish oil-based lipid source.

    PubMed

    Venecourt-Jackson, Esra; Hill, Simon J; Walmsley, Russell S

    2013-01-01

    Liver disease occurs in 15% to 40% of adults on long-term parenteral nutrition, with steatosis being more common than cholestasis in the adult population. This problem has been well reported in the pediatric population, but we describe the case of a man who became profoundly jaundiced after being on parenteral nutrition for 3 y and responded rapidly to a change in lipid source from soybean and olive oil-based emulsion (ClinOleic) to a fish oil-based lipid emulsion (Omegaven).

  17. Importance of floodplain connectivity to fish populations in the Apalachicola River, Florida

    USGS Publications Warehouse

    Burgess, O.T.; Pine, William E.; Walsh, S.J.

    2013-01-01

    Floodplain habitats provide critical spawning and rearing habitats for many large-river fishes. The paradigm that floodplains are essential habitats is often a key reason for restoring altered rivers to natural flow regimes. However, few studies have documented spatial and temporal utilization of floodplain habitats by adult fish of sport or commercial management interest or assessed obligatory access to floodplain habitats for species' persistence. In this study, we applied telemetry techniques to examine adult fish movements between floodplain and mainstem habitats, paired with intensive light trap sampling of larval fish in these same habitats, to assess the relationships between riverine flows and fish movement and spawning patterns in restored and unmodified floodplain distributaries of the Apalachicola River, Florida. Our intent is to inform resource managers on the relationships between the timing, magnitude and duration of flow events and fish spawning as part of river management actions. Our results demonstrate spawning by all study species in floodplain and mainstem river habitat types, apparent migratory movements of some species between these habitats, and distinct spawning events for each study species on the basis of fish movement patterns and light trap catches. Additionally, Micropterus spp., Lepomis spp. and, to a lesser degree, Minytrema melanops used floodplain channel habitat that was experimentally reconnected to the mainstem within a few weeks of completing the restoration. This result is of interest to managers assessing restoration activities to reconnect these habitats as part of riverine restoration programmes globally.

  18. Increasing the Success of Adults from Diverse Populations.

    ERIC Educational Resources Information Center

    Sheckley, Barry G.; Keeton, Morris T.

    1995-01-01

    The following methods can increase the academic success of adults from diverse populations: focus on how educational circumstances are experienced by individuals, not broad groups; maximize time spent on tasks related to course/degree requirements; and reduce student costs in terms of time, money, frustration, and stress. (SK)

  19. Estimated Full Scale IQ in an Adult Heroin Addict Population.

    ERIC Educational Resources Information Center

    Chastain, Robert L.; And Others

    The research concerning intellectual functioning in addict populations has not addressed basic questions concerning why and how intelligence quotients (IQ) might be related to drug addiction. A study was undertaken to estimate intellectual functioning based upon a demographic profile for Wechsler Adult Intelligence Scale-Revised (WAIS-R) Full…

  20. An integrative approach to assess ecological risks of surface water contamination for fish populations.

    PubMed

    Santos, Raphael; Joyeux, Aude; Besnard, Aurélien; Blanchard, Christophe; Halkett, Cédric; Bony, Sylvie; Sanchez, Wilfried; Devaux, Alain

    2017-01-01

    Contamination of aquatic ecosystems is considered as one of the main threats to global freshwater biodiversity. Within the European Water Framework Directive (EU-WFD) a particular attention is dedicated to assess ecological risks of surface water contamination and mitigation of chemical pressures on aquatic ecosystems. In this work, we evaluated ecological risks of surface water contamination for fish populations in four EU-WFD rivers through an integrative approach investigating three Lines of Evidence (chemical contamination, biomarker responses as early warning signals of contamination impacting individuals and ecological analyses as an indicator of fish community disturbances). This work illustrates through 4 case studies the complementary role of biomarkers, chemical and ecological analyses which, used in combination, provide fundamental information to understand impacts of chemical pressures that can affect fish population dynamics. We discuss the limitations of this approach and future improvements needed within the EU-WFD to assess ecological risk of river contamination for fish populations.

  1. Genotypic structure of a Drosophila population for adult locomotor activity

    SciTech Connect

    Grechanyi, G.V.; Korzun, V.M.

    1995-01-01

    Analysis of the variation of adult locomotor activity in four samples taken at different times from a natural population of Drosophila melanogaster showed that the total variation of this trait is relatively stable in time and has a substantial genetic component. Genotypic structure of the population for locomotor activity is characterized by the presence of large groups of genotypes with high and low values of this trait. A possible explanation for the presence of such groups in a population is cyclic density-dependent selection.

  2. Estimating mortality rates of adult fish from entrainment through the propellers of river towboats

    USGS Publications Warehouse

    Gutreuter, S.; Dettmers, J.M.; Wahl, David H.

    2003-01-01

    We developed a method to estimate mortality rates of adult fish caused by entrainment through the propellers of commercial towboats operating in river channels. The method combines trawling while following towboats (to recover a fraction of the kills) and application of a hydrodynamic model of diffusion (to estimate the fraction of the total kills collected in the trawls). The sampling problem is unusual and required quantifying relatively rare events. We first examined key statistical properties of the entrainment mortality rate estimators using Monte Carlo simulation, which demonstrated that a design-based estimator and a new ad hoc estimator are both unbiased and converge to the true value as the sample size becomes large. Next, we estimated the entrainment mortality rates of adult fishes in Pool 26 of the Mississippi River and the Alton Pool of the Illinois River, where we observed kills that we attributed to entrainment. Our estimates of entrainment mortality rates were 2.52 fish/km of towboat travel (80% confidence interval, 1.00-6.09 fish/km) for gizzard shad Dorosoma cepedianum, 0.13 fish/km (0.00-0.41) for skipjack herring Alosa chrysochloris, and 0.53 fish/km (0.00-1.33) for both shovelnose sturgeon Scaphirhynchus platorynchus and smallmouth buffalo Ictiobus bubalus. Our approach applies more broadly to commercial vessels operating in confined channels, including other large rivers and intracoastal waterways.

  3. Fishery-Independent Data Reveal Negative Effect of Human Population Density on Caribbean Predatory Fish Communities

    PubMed Central

    Stallings, Christopher D.

    2009-01-01

    Background Understanding the current status of predatory fish communities, and the effects fishing has on them, is vitally important information for management. However, data are often insufficient at region-wide scales to assess the effects of extraction in coral reef ecosystems of developing nations. Methodology/Principal Findings Here, I overcome this difficulty by using a publicly accessible, fisheries-independent database to provide a broad scale, comprehensive analysis of human impacts on predatory reef fish communities across the greater Caribbean region. Specifically, this study analyzed presence and diversity of predatory reef fishes over a gradient of human population density. Across the region, as human population density increases, presence of large-bodied fishes declines, and fish communities become dominated by a few smaller-bodied species. Conclusions/Significance Complete disappearance of several large-bodied fishes indicates ecological and local extinctions have occurred in some densely populated areas. These findings fill a fundamentally important gap in our knowledge of the ecosystem effects of artisanal fisheries in developing nations, and provide support for multiple approaches to data collection where they are commonly unavailable. PMID:19421312

  4. Length-based assessment of coral reef fish populations in the main and northwestern Hawaiian islands.

    PubMed

    Nadon, Marc O; Ault, Jerald S; Williams, Ivor D; Smith, Steven G; DiNardo, Gerard T

    2015-01-01

    The coral reef fish community of Hawaii is composed of hundreds of species, supports a multimillion dollar fishing and tourism industry, and is of great cultural importance to the local population. However, a major stock assessment of Hawaiian coral reef fish populations has not yet been conducted. Here we used the robust indicator variable "average length in the exploited phase of the population ([Formula: see text])", estimated from size composition data from commercial fisheries trip reports and fishery-independent diver surveys, to evaluate exploitation rates for 19 Hawaiian reef fishes. By and large, the average lengths obtained from diver surveys agreed well with those from commercial data. We used the estimated exploitation rates coupled with life history parameters synthesized from the literature to parameterize a numerical population model and generate stock sustainability metrics such as spawning potential ratios (SPR). We found good agreement between predicted average lengths in an unfished population (from our population model) and those observed from diver surveys in the largely unexploited Northwestern Hawaiian Islands. Of 19 exploited reef fish species assessed in the main Hawaiian Islands, 9 had SPRs close to or below the 30% overfishing threshold. In general, longer-lived species such as surgeonfishes, the redlip parrotfish (Scarus rubroviolaceus), and the gray snapper (Aprion virescens) had the lowest SPRs, while short-lived species such as goatfishes and jacks, as well as two invasive species (Lutjanus kasmira and Cephalopholis argus), had SPRs above the 30% threshold.

  5. Length-Based Assessment of Coral Reef Fish Populations in the Main and Northwestern Hawaiian Islands

    PubMed Central

    Nadon, Marc O.; Ault, Jerald S.; Williams, Ivor D.; Smith, Steven G.; DiNardo, Gerard T.

    2015-01-01

    The coral reef fish community of Hawaii is composed of hundreds of species, supports a multimillion dollar fishing and tourism industry, and is of great cultural importance to the local population. However, a major stock assessment of Hawaiian coral reef fish populations has not yet been conducted. Here we used the robust indicator variable “average length in the exploited phase of the population (L¯)”, estimated from size composition data from commercial fisheries trip reports and fishery-independent diver surveys, to evaluate exploitation rates for 19 Hawaiian reef fishes. By and large, the average lengths obtained from diver surveys agreed well with those from commercial data. We used the estimated exploitation rates coupled with life history parameters synthesized from the literature to parameterize a numerical population model and generate stock sustainability metrics such as spawning potential ratios (SPR). We found good agreement between predicted average lengths in an unfished population (from our population model) and those observed from diver surveys in the largely unexploited Northwestern Hawaiian Islands. Of 19 exploited reef fish species assessed in the main Hawaiian Islands, 9 had SPRs close to or below the 30% overfishing threshold. In general, longer-lived species such as surgeonfishes, the redlip parrotfish (Scarus rubroviolaceus), and the gray snapper (Aprion virescens) had the lowest SPRs, while short-lived species such as goatfishes and jacks, as well as two invasive species (Lutjanus kasmira and Cephalopholis argus), had SPRs above the 30% threshold. PMID:26267473

  6. Ocean Acidification Effects on Atlantic Cod Larval Survival and Recruitment to the Fished Population.

    PubMed

    Stiasny, Martina H; Mittermayer, Felix H; Sswat, Michael; Voss, Rüdiger; Jutfelt, Fredrik; Chierici, Melissa; Puvanendran, Velmurugu; Mortensen, Atle; Reusch, Thorsten B H; Clemmesen, Catriona

    2016-01-01

    How fisheries will be impacted by climate change is far from understood. While some fish populations may be able to escape global warming via range shifts, they cannot escape ocean acidification (OA), an inevitable consequence of the dissolution of anthropogenic carbon dioxide (CO2) emissions in marine waters. How ocean acidification affects population dynamics of commercially important fish species is critical for adapting management practices of exploited fish populations. Ocean acidification has been shown to impair fish larvae's sensory abilities, affect the morphology of otoliths, cause tissue damage and cause behavioural changes. Here, we obtain first experimental mortality estimates for Atlantic cod larvae under OA and incorporate these effects into recruitment models. End-of-century levels of ocean acidification (~1100 μatm according to the IPCC RCP 8.5) resulted in a doubling of daily mortality rates compared to present-day CO2 concentrations during the first 25 days post hatching (dph), a critical phase for population recruitment. These results were consistent under different feeding regimes, stocking densities and in two cod populations (Western Baltic and Barents Sea stock). When mortality data were included into Ricker-type stock-recruitment models, recruitment was reduced to an average of 8 and 24% of current recruitment for the two populations, respectively. Our results highlight the importance of including vulnerable early life stages when addressing effects of climate change on fish stocks.

  7. Ocean Acidification Effects on Atlantic Cod Larval Survival and Recruitment to the Fished Population

    PubMed Central

    Stiasny, Martina H.; Mittermayer, Felix H.; Sswat, Michael; Voss, Rüdiger; Jutfelt, Fredrik; Chierici, Melissa; Puvanendran, Velmurugu; Mortensen, Atle; Reusch, Thorsten B. H.; Clemmesen, Catriona

    2016-01-01

    How fisheries will be impacted by climate change is far from understood. While some fish populations may be able to escape global warming via range shifts, they cannot escape ocean acidification (OA), an inevitable consequence of the dissolution of anthropogenic carbon dioxide (CO2) emissions in marine waters. How ocean acidification affects population dynamics of commercially important fish species is critical for adapting management practices of exploited fish populations. Ocean acidification has been shown to impair fish larvae’s sensory abilities, affect the morphology of otoliths, cause tissue damage and cause behavioural changes. Here, we obtain first experimental mortality estimates for Atlantic cod larvae under OA and incorporate these effects into recruitment models. End-of-century levels of ocean acidification (~1100 μatm according to the IPCC RCP 8.5) resulted in a doubling of daily mortality rates compared to present-day CO2 concentrations during the first 25 days post hatching (dph), a critical phase for population recruitment. These results were consistent under different feeding regimes, stocking densities and in two cod populations (Western Baltic and Barents Sea stock). When mortality data were included into Ricker-type stock-recruitment models, recruitment was reduced to an average of 8 and 24% of current recruitment for the two populations, respectively. Our results highlight the importance of including vulnerable early life stages when addressing effects of climate change on fish stocks. PMID:27551924

  8. Linking temporal changes in the demographic structure and individual growth to the decline in the population of a tropical fish

    NASA Astrophysics Data System (ADS)

    Sirot, Charlotte; Darnaude, Audrey M.; Guilhaumon, François; Ramos-Miranda, Julia; Flores-Hernandez, Domingo; Panfili, Jacques

    2015-11-01

    The exceptional biodiversity and productivity of tropical coastal lagoons can only be preserved by identifying the causes for the decline in the populations living in these vulnerable ecosystems. The Terminos lagoon in Mexico provided an opportunity for studying this issue as some of its fish populations, in particular the Silver Perch (Bairdiella chrysoura), have declined significantly since the 1980s. Fish sampling campaigns carried out over the whole lagoon area in 1979-81 and again in 2006-2011 revealed the mechanisms which may have been responsible for this decline. Based on biometrical data for 295 juveniles and adults from the two periods and on somatic growth derived from 173 otoliths, a study of the temporal changes in the demographic structure and life history traits (individual growth and body condition) made it possible to distinguish the causes of the decline in the B. chrysoura population. Growth models for the lagoon in 1980-1981 and 2006-2011 showed no significant change in the growth parameters of the population over the last 30 years with a logistic model giving an accurate estimate (R2 = 0.66) of the size-at-age for both periods. The decline in the B. chrysoura population could not be explained by an overall decrease in individual size and condition in the lagoon, the average standard length (SL) and Fulton index (FI) having increased slightly since 1980-1981 (4.6 mm and 0.02 for juveniles and 5.42 mm and 0.07 for adults). However, the size structure of the population in the lagoon has changed, with a significant shift in the size distribution of juveniles with a marked reduction in the proportion of juveniles ≤ 60 mm in the captures (90.9% fewer than in 1980-1981). As the otolith growth rate of fish during the first 4 months also decreased significantly between the two sampling periods (-15%), it is suggested that the main reason for the decline in the abundance and biomass of B. chrysoura within this system may be that its habitats are less

  9. Remarkable vertical shift in residence depth links pelagic larval and demersal adult jellynose fish

    NASA Astrophysics Data System (ADS)

    Shiao, Jen-Chieh; Sui, Tsung-Da; Chang, Ni-Na; Chang, Chih-Wei

    2017-03-01

    Deep-sea fish show diverse migratory behaviors across depths at different life stages. The historical residence depths of jellynose fish Ateleopus japonicus and Ijimaia dofleini (Ateleopodidae) were reconstructed from otolith microstructures and isotopic compositions. δ18O values in the otolith core areas ranged from -0.5 to -1.3‰ among individuals, suggesting that larval and post-larval stages lived in the mixed layer (50-200 m). Otolith growth increment widths surged for 10-30 rings around 300-600 μm from the core, indicating a fast-growth phase during the early post-larval stage. Fish then migrated downward to 350-800 m depth at about 2 months of age, possibly during the post-larval metamorphosis to the juvenile. Otolith growth increments became narrower and otolith δ13C values increased from -5 to -1‰, suggesting a lower growth and metabolic rate when the fish experienced colder water during the downward migration. After arrival at the deepest waters, the fish then migrated upward to the continental margin or upper slopes where the adults persistently resided. A translucent otolith zone was formed after the residence depth shift from the deepest waters to shallower depths, indicating a transition from pelagic to bathydemersal life on the continental shelf or break. The down-and-up shift in residence depth of jellynose fish represents an indirect settlement process to the adult residence depth, which might be associated with a unique post-larval stage moving offshore before the downward migration. The results filled the gap of vertical distributions of jellynose fish from pelagic larvae near the sea surface to the bathydemersal adult dwelling on the continental shelf break.

  10. Assessing risks to fish populations near a proposed disposal facility for used nuclear fuel

    SciTech Connect

    Hart, D.; Miesenheimer, P.; Hull, R.

    1995-12-31

    The concept of used nuclear fuel disposal in the Canadian Shield is currently undergoing a federal environmental assessment review process. As part of this review, potential risks to brook trout populations in the vicinity of such an underground repository were considered. Chemical fate, transport and exposure models have been utilized to estimate the dose rates from released radionuclides and other fuel constituents, and these likely will not be sufficient to harm fish in nearby streams. However, other stressors such as habitat alteration (e.g., loss of upwelling) and/or fishing pressure associated with increased public access could have significant population impacts if the site is located in a pristine northern region. Population models are utilized to explore the risks of local population reduction for different combinations of fishing pressure and habitat degradation.

  11. Biomarker measurements in a coastal fish-eating population environmentally exposed to organochlorines.

    PubMed

    Ayotte, Pierre; Dewailly, Eric; Lambert, George H; Perkins, Sherry L; Poon, Raymond; Feeley, Mark; Larochelle, Christian; Pereg, Daria

    2005-10-01

    The Lower North Shore region of the St. Lawrence River is home to a fish-eating population that displays an unusually high body burden of several organochlorines, including polychlorinated biphenyls (PCBs) and dioxin-like compounds (DLCs). We measured biomarkers indicative of liver enzyme induction and investigated the relationship with organochlorine body burden in adult volunteers from this population. We determined plasma concentrations of PCBs and chlorinated pesticides by high-resolution gas chromatography (HRGC) with electron capture detection. DLC concentrations were measured by the dioxin-receptor chemically activated luciferase expression (DR-CALUX) assay and in a subset of participants, by HRGC/high-resolution mass spectrometry. We measured cotinine, d-glucaric acid, and porphyrins in morning urine samples and determined liver CYP1A2 activity in vivo using the caffeine breath test. Neither DLC concentrations as measured by the DR-CALUX nor PCB-153 concentrations, the latter representing total PCB exposure, were correlated with biomarkers of effects. Smoking (morning urinary cotinine concentration) was positively related to CYP1A2 activity as measured by the caffeine breath test (p < 0.01). Liver CYP1A2 activity was in turn negatively correlated with PCB-105:PCB-153 and PCB-118:PCB-153 congener ratios (p < 0.05). Hence, despite the relatively high body burden of PCBs and DLCs in this population, only smoking had a significant correlation with biomarkers of hepatic enzyme induction. Our data are consistent with smoking-induced liver CYP1A2 activity altering heme metabolism and increasing the biotransformation of mono-ortho PCB congeners.

  12. Physiological responses of adult rainbow trout experimentally released through a unique fish conveyance device

    USGS Publications Warehouse

    Mesa, Matthew G.; Gee, Lisa P.; Weiland, Lisa K.; Christiansen, Helena E.

    2013-01-01

    We assessed the physiological stress responses (i.e., plasma levels of cortisol, glucose, and lactate) of adult Rainbow Trout Oncorhynchus mykiss at selected time intervals after they had passed a distance of 15 m through a unique fish conveyance device (treatment fish) or not (controls). This device differs from traditional fish pumps in two important ways: (1) it transports objects in air, rather than pumping them from and with water; and (2) it uses a unique tube for transport that has a series of soft, deformable baffles spaced evenly apart and situated perpendicular within a rigid, but flexible outer shell. Mean concentrations of the plasma constituents never differed (P > 0.05) between control and treatment fish at 0, 1, 4, 8, or 24 h after passage, and only minor differences were apparent between the different time intervals within a group. We observed no obvious injuries on any of our fish. Our results indicate that passage through this device did not severely stress or injure fish and it may allow for the rapid and safe movement of fish at hatcheries, sorting or handling facilities, or passage obstacles.

  13. Inter-class competition in stage-structured populations: effects of adult density on life-history traits of adult and juvenile common lizards.

    PubMed

    San-Jose, Luis M; Peñalver-Alcázar, Miguel; Huyghe, Katleen; Breedveld, Merel C; Fitze, Patrick S

    2016-12-01

    Ecological and evolutionary processes in natural populations are largely influenced by the population's stage-structure. Commonly, different classes have different competitive abilities, e.g., due to differences in body size, suggesting that inter-class competition may be important and largely asymmetric. However, experimental evidence states that inter-class competition, which is important, is rare and restricted to marine fish. Here, we manipulated the adult density in six semi-natural populations of the European common lizard, Zootoca vivipara, while holding juvenile density constant. Adult density affected juveniles, but not adults, in line with inter-class competition. High adult density led to lower juvenile survival and growth before hibernation. In contrast, juvenile survival after hibernation was higher in populations with high adult density, pointing to relaxed inter-class competition. As a result, annual survival was not affected by adult density, showing that differences in pre- and post-hibernation survival balanced each other out. The intensity of inter-class competition affected reproduction, performance, and body size in juveniles. Path analyses unravelled direct treatment effects on early growth (pre-hibernation) and no direct treatment effects on the parameters measured after hibernation. This points to allometry of treatment-induced differences in early growth, and it suggests that inter-class competition mainly affects the early growth of the competitively inferior class and thereby their future performance and reproduction. These results are in contrast with previous findings and, together with results in marine fish, suggest that the strength and direction of density dependence may depend on the degree of inter-class competition, and thus on the availability of resources used by the competing classes.

  14. Spatially explicit modeling of habitat dynamics and fish population persistence in an intermittent lowland stream.

    PubMed

    Perry, George L W; Bond, Nicholas R

    2009-04-01

    In temperate and arid climate zones many streams and rivers flow intermittently, seasonally contracting to a sequence of isolated pools or waterholes over the dry period, before reconnecting in the wetter parts of the year. This seasonal drying process is central to our understanding of the population dynamics of aquatic organisms such as fish and invertebrates in these systems. However, there is a dearth of empirical data on the temporal dynamics of such populations. We describe a spatially explicit individual-based model (SEIBM) of fish population dynamics in such systems, which we use to explore the long-term population viability of the carp gudgeon Hypseleotris spp. in a lowland stream in southeastern Australia. We explicitly consider the impacts of interannual variability in stream flow, for example, due to drought, on habitat availability and hence population persistence. Our results support observations that these populations are naturally highly variable, with simulated fish population sizes typically varying over four orders of magnitude within a 50-year simulation run. The most sensitive parameters in the model relate to the amount of water (habitat) in the system: annual rainfall, seepage loss from the pools, and the carrying capacity (number of individuals per cubic meter) of the pools as they dry down. It seems likely that temporal source sink dynamics allow the fish populations to persist in these systems, with good years (high rainfall and brief cease-to-flow [CTF] periods) buffering against periods of drought. In dry years during which the stream may contract to very low numbers of pools, each of these persistent pools becomes crucial for the persistence of the population in the system. Climate change projections for this area suggest decreases in rainfall and increased incidence of drought; under these environmental conditions the long-term persistence of these fish populations is uncertain.

  15. Predation risk influences adaptive morphological variation in fish populations.

    PubMed

    Eklöv, Peter; Svanbäck, Richard

    2006-03-01

    Predators can cause a shift in both density and frequency of a prey phenotype that may lead to phenotypic divergence through natural selection. What is less investigated is that predators have a variety of indirect effects on prey that could potentially have large evolutionary responses. We conducted a pond experiment to test whether differences in predation risk in different habitats caused shifts in behavior of prey that, in turn, would affect their morphology. We also tested whether the experimental data could explain the morphological variation of perch in the natural environment. In the experiment, predators caused the prey fish to shift to the habitat with the lower predation risk. The prey specialized on habitat-specific resources, and there was a strong correlation between diet of the prey fish and morphological variation, suggesting that resource specialization ultimately affected the morphology. The lack of differences in competition and mortality suggest that the morphological variation among prey was induced by differences in predation risk among habitats. The field study demonstrated that there are differences in growth related to morphology of perch in two different habitats. Thus, a trade-off between foraging and predator avoidance could be responsible for adaptive morphological variation of young perch.

  16. Tidal management sffects sub-adult fish assemblages in impounded South Carolina Marshes

    USGS Publications Warehouse

    Carswell, Ben L.; Peterson, James T.; Jennings, Cecil A.

    2015-01-01

    In coastal South Carolina, most impounded marshes are managed for waterfowl; fewer are managed for fishes. Tidal control is central to each strategy but raises concerns that nursery function could be impaired. This research examined the assemblage composition of fishes during early-life stages. We sampled two impoundments of each management type monthly in 2008 and 2009. We used light traps to collect 61,527 sub-adult fish representing 21 species and 16 families and push nets to collect 12,670 sub-adult fish representing 13 species and 11 families. The effective number of species detected at larval stage in “fish” impoundments (summer mean = 2.52 ± 0.20, winter mean = 2.02 ± 0.66) was greater than in “waterfowl” impoundments (summer mean = 1.27 ± 0.14, winter mean = 1.06 ± 0.09); CI = 90 %. Species richness did not differ between management types, but hierarchical linear models predicted differences in assemblage composition. These findings underscore the importance of frequent water exchange for maintaining diverse assemblages of early-life-stage fishes in marsh impoundments.

  17. Contaminant effects on Great Lakes' fish-eating birds: a population perspective

    USGS Publications Warehouse

    Heinz, G.H.; Kendall, Ronald J.; Dickerson, Richard L.; Giesy, John P.; Suk, William P.

    1998-01-01

    Preventing environmental contaminants from reducing wildlife populations is the greatest concern in wildlife toxicology. In the Great Lakes, environmental contaminants have a history of reducing populations of many species of fish-eating birds. Endocrine effects may have contributed to declines in fish-eating bird populations, but the overriding harm was caused by DDE-induced eggshell thinning. Toxic effects may still be occurring today, but apparently they are not of a sufficient magnitude to depress populations of most fish-eating birds. Once DDE levels in the Great Lakes declined, eggshells of birds began to get thicker and reproductive success improved. Populations of double-crested cormorants (Phalacrocorax auritus) and ring-billed gulls (Larus delawarensis) have increased dramatically since the bans on DDT and other organochlorine pesticides. Bald eagles (Haliaeetus leucocephalus) are still not reproducing at a normal rate along the shores of the Great Lakes, but success is much improved compared to earlier records when eggshell thinning was worse. Other species, such as herring gulls (Larus argentatus) and black-crowned night-herons (Nycticorax nycticorax), seem to be having improved reproductive success, but data on Great Lakes'-wide population changes are incomplete. Reproductive success of common terns (Sterna hirundo), Caspian terns (Sterna caspia), and Forster's terns (Sterna forsteri) seems to have improved in recent years, but, again, data on population changes are not very complete, and these birds face many habitat related problems as well as contaminant problems. Although contaminants are still producing toxic effects, and these effects may include endocrine disfunction, fish-eating birds in the Great Lakes seem to be largely weathering these effects, at least as far as populations are concerned. A lack of obvious contaminant effects on populations of fish-eating birds in the Great Lakes, however, should not be equated with a lack of any harm to

  18. Evaluation of Juvenile Fish Bypass and Adult Fish Passage Facilities at Three-Mile Falls Dam; Umatilla River, Oregon, 1989 Annual Report.

    SciTech Connect

    Nigro, Anthony A.

    1990-09-01

    We report on our progress from October 1989 through September 1990 on evaluating juvenile fish bypass and adult fish passage facilities at Three Mile Falls Dam on the Umatilla River. The study is a cooperative effort by the Oregon Department of Fish and Wildlife (ODFW) and the Confederated Tribes of the Umatilla Indian Reservation (CTUIR). Study objectives addressed by ODFW and CTUIR are: (1) ODFW (Report A): Operate and evaluate the juvenile fish bypass system in the West Extension Irrigation District canal at Three Mile Falls Dam; and (2) CTUIR (Report 8): Examine the passage of adult salmonids at Three Mile Falls Dam. The study is part of a program to rehabilitate anadromous fish stocks in the Umatilla River Basin that includes restorations of coho salmon Oncorhynchus Wsutch and chinook salmon 0. tshawytscha and enhancement of summer steelhead 0. mytiss.

  19. The Consumption of Breakfast, Fish and/or Caffeine does not Predict Study Progress in Adult Distance Education.

    PubMed

    Gijselaers, Hieronymus J M; Kirschner, Paul A; de Groot, Renate H M

    2016-10-06

    Consumption of breakfast, fish, or caffeine are each separately often investigated in relation to learning performance in traditional education, but not in distance education (DE). The objective of this study was to investigate whether the relations between the consumption of breakfast, fish, and/or caffeine on the one hand and learning performance on the other are also found in DE students. This population is different from traditional students and characterized by a different profile in terms of age, personal and work responsibilities as well as other demographics. In an observational longitudinal study, the consumption of breakfast, fish, and caffeine of 1157 DE students (18-76 years old, mean 35.8±11.1 years) was used to predict learning performance using multiple regression analysis. In an online digital survey, university students provided information about their consumption of these nutritional measures and on important covariates. Learning performance, measured as study progress (i.e., the number of successfully completed modules), was evaluated objectively after 14 months. Results showed that adding the consumption of breakfast, fish, and caffeine to the covariate model did not fit the data better, χ(2) (3, N = 1155) = 3.287, p = 0.35. This means that neither the consumption of breakfast nor fish nor caffeine predicted study progress in adults participating in DE. This study is important as it is the first to report on these relations in this specific age group and educational setting, which is increasingly important due to the increased preference for this type of education.

  20. Low genetic differentiation between two geographically separated populations of demersal gadiform fishes in the Southern Hemisphere.

    PubMed

    Takeshima, Hirohiko; Hatanaka, Akimasa; Yamada, Syo-ichi; Yamazaki, Yuji; Kimura, Ikuo; Nishida, Mutsumi

    2011-01-01

    The distribution patterns of many fishes between the three continents (Africa, Australia, and South America) in the Southern Hemisphere have been uncovered to be influenced by mostly vicariance or historical dispersal. Although some demersal fishes with intercontinental distribution are suggested to be more influenced by current/recent dispersal, few genetic studies have been made for demersal fishes so far. To provide more information for such fishes, genetic divergence was analyzed for two pairs of gadiform species and subspecies distributed around Australasia and South America: the blue grenadier, Macruronus novaezelandiae (from New Zealand) and the Patagonian grenadier, M. magellanicus (from South America) as well as two subspecies of the southern blue whiting, Micromesistius australis pallidus (from New Zealand) and M. a. australis (from South America). The sequence analyses of two mitochondrial DNA regions showed no divergence between Australasian and South American populations of the grenadiers and the southern blue whiting. The microsatellite DNA analysis also indicated significant but very minimal genetic differentiation between the two geographic populations of each pair. These results imply rather recent separation of the two geographic populations. Current/recent dispersal may be an important common factor for determining the distribution of demersal fishes in the Southern Hemisphere. Nonetheless, low but significant genetic differentiation observed requires treating the two populations of the economically important grenadiers and southern blue whiting, respectively, as different stocks for proper resource management.

  1. Fish abundance and population stability in a reservoir tailwater and an unregulated headwater stream

    USGS Publications Warehouse

    Jacobs, K.E.; Swink, W.D.

    1983-01-01

    Fish abundance and population stability were compared in the tailwater and in an unregulated tributary of Barren River Lake, a flood control reservoir in south central Kentucky. Fish abundance was greater in the tailwater near the dam and was dominated by three species common in the reservoir: gizzard shad (Dorosoma cepedianum), bluegills (Lepomis macrochirus), and white crappies (Pomoxis annularis). Three riverine suckers were less abundant in the tailwater than in the unregulated stream: northern hog suckers (Hypentelium nigricans), black redhorse (Moxostoma duquesnei), and golden redhorse (Moxostoma erythrurum). The fish populations in the tailwater, particularly common carp (Cyprinus carpio), northern hog suckers, black redhorse, and golden redhorse, were less stable than those in the unregulated stream. Population stability is defined as the extent to which fish remain in a stream section. This study suggests that the occurrence of reservoir species in the tailwater was the result of fish passage from the reservoir during high discharges in fall and winter. Reservoir operations (altered flow, low summer water temperature, and poor summer water quality) probably were responsible for the unstable populations of common carp and riverine suckers in the tailwater.

  2. High intake of fatty fish, but not of lean fish, affects serum concentrations of TAG and HDL-cholesterol in healthy, normal-weight adults: a randomised trial.

    PubMed

    Hagen, Ingrid V; Helland, Anita; Bratlie, Marianne; Brokstad, Karl A; Rosenlund, Grethe; Sveier, Harald; Mellgren, Gunnar; Gudbrandsen, Oddrun A

    2016-08-01

    The aim of the present study was to examine whether high intake of lean or fatty fish (cod and farmed salmon, respectively) by healthy, normal-weight adults would affect risk factors of type 2 diabetes and CVD when compared with lean meat (chicken). More knowledge is needed concerning the potential health effects of high fish intake (>300 g/week) in normal-weight adults. In this randomised clinical trial, thirty-eight young, healthy, normal-weight participants consumed 750 g/week of lean or fatty fish or lean meat (as control) for 4 weeks at dinner according to provided recipes to ensure similar ways of preparations and choices of side dishes between the groups. Energy and macronutrient intakes at baseline and end point were similar in all groups, and there were no changes in energy and macronutrient intakes within any of the groups during the course of the study. High intake of fatty fish, but not lean fish, significantly reduced TAG and increased HDL-cholesterol concentrations in fasting serum when compared with lean meat intake. When compared with lean fish intake, fatty fish intake increased serum HDL-cholesterol. No differences were observed between lean fish, fatty fish and lean meat groups regarding fasting and postprandial glucose regulation. These findings suggest that high intake of fatty fish, but not of lean fish, could beneficially affect serum concentrations of TAG and HDL-cholesterol, which are CVD risk factors, in healthy, normal-weight adults, when compared with high intake of lean meat.

  3. A computer program for estimating fish population sizes and annual production rates

    SciTech Connect

    Railsback, S.F.; Holcomb, B.D.; Ryon, M.G.

    1989-10-01

    This report documents a program that estimates fish population sizes and annual production rates in small streams from multiple-pass sampling data. A maximum weighted likelihood method is used to estimate population sizes (Carle and Strub, 1978), and a size-frequency method is used to estimate production (Garman and Waters, 1983). The program performs the following steps: (1) reads in the data and performs error checking; (2) where required, uses length-weight regression to fill in missing weights; (3) assigns length classes to the fish; (4) for each date, species, and length class, estimates the population size and its variance; (5) for each date and species, estimates the total population size and its variance; and (6) for each species, estimates the annual production rate and its variance between sampling dates selected by the user. If data from only date are used, only populations are estimated. 9 refs.

  4. It is the economy, stupid! Projecting the fate of fish populations using ecological-economic modeling.

    PubMed

    Quaas, Martin F; Reusch, Thorsten B H; Schmidt, Jörn O; Tahvonen, Olli; Voss, Rudi

    2016-01-01

    Four marine fish species are among the most important on the world market: cod, salmon, tuna, and sea bass. While the supply of North American and European markets for two of these species - Atlantic salmon and European sea bass - mainly comes from fish farming, Atlantic cod and tunas are mainly caught from wild stocks. We address the question what will be the status of these wild stocks in the midterm future, in the year 2048, to be specific. Whereas the effects of climate change and ecological driving forces on fish stocks have already gained much attention, our prime interest is in studying the effects of changing economic drivers, as well as the impact of variable management effectiveness. Using a process-based ecological-economic multispecies optimization model, we assess the future stock status under different scenarios of change. We simulate (i) technological progress in fishing, (ii) increasing demand for fish, and (iii) increasing supply of farmed fish, as well as the interplay of these driving forces under different scenarios of (limited) fishery management effectiveness. We find that economic change has a substantial effect on fish populations. Increasing aquaculture production can dampen the fishing pressure on wild stocks, but this effect is likely to be overwhelmed by increasing demand and technological progress, both increasing fishing pressure. The only solution to avoid collapse of the majority of stocks is institutional change to improve management effectiveness significantly above the current state. We conclude that full recognition of economic drivers of change will be needed to successfully develop an integrated ecosystem management and to sustain the wild fish stocks until 2048 and beyond.

  5. An empirical model for estimating annual consumption by freshwater fish populations

    USGS Publications Warehouse

    Liao, H.; Pierce, C.L.; Larscheid, J.G.

    2005-01-01

    Population consumption is an important process linking predator populations to their prey resources. Simple tools are needed to enable fisheries managers to estimate population consumption. We assembled 74 individual estimates of annual consumption by freshwater fish populations and their mean annual population size, 41 of which also included estimates of mean annual biomass. The data set included 14 freshwater fish species from 10 different bodies of water. From this data set we developed two simple linear regression models predicting annual population consumption. Log-transformed population size explained 94% of the variation in log-transformed annual population consumption. Log-transformed biomass explained 98% of the variation in log-transformed annual population consumption. We quantified the accuracy of our regressions and three alternative consumption models as the mean percent difference from observed (bioenergetics-derived) estimates in a test data set. Predictions from our population-size regression matched observed consumption estimates poorly (mean percent difference = 222%). Predictions from our biomass regression matched observed consumption reasonably well (mean percent difference = 24%). The biomass regression was superior to an alternative model, similar in complexity, and comparable to two alternative models that were more complex and difficult to apply. Our biomass regression model, log10(consumption) = 0.5442 + 0.9962??log10(biomass), will be a useful tool for fishery managers, enabling them to make reasonably accurate annual population consumption predictions from mean annual biomass estimates. ?? Copyright by the American Fisheries Society 2005.

  6. Dispersal capacity predicts both population genetic structure and species richness in reef fishes.

    PubMed

    Riginos, Cynthia; Buckley, Yvonne M; Blomberg, Simon P; Treml, Eric A

    2014-07-01

    Dispersal is a fundamental species characteristic that should directly affect both rates of gene flow among spatially distributed populations and opportunities for speciation. Yet no single trait associated with dispersal has been demonstrated to affect both micro- and macroevolutionary patterns of diversity across a diverse biological assemblage. Here, we examine patterns of genetic differentiation and species richness in reef fishes, an assemblage of over 7,000 species comprising approximately one-third of the extant bony fishes and over one-tenth of living vertebrates. In reef fishes, dispersal occurs primarily during a planktonic larval stage. There are two major reproductive and parental investment syndromes among reef fishes, and the differences between them have implications for dispersal: (1) benthic guarding fishes lay negatively buoyant eggs, typically guarded by the male parent, and from these eggs hatch large, strongly swimming larvae; in contrast, (2) pelagic spawning fishes release small floating eggs directly into the water column, which drift unprotected before small weakly swimming larvae hatch. Using phylogenetic comparative methods, we show that benthic guarders have significantly greater population structure than pelagic spawners and additionally that taxonomic families of benthic guarders are more species rich than families of pelagic spawners. Our findings provide a compelling case for the continuity between micro- and macroevolutionary processes of biological diversification and underscore the importance of dispersal-related traits in influencing the mode and tempo of evolution.

  7. Discrimination of fish populations using parasites: Random Forests on a 'predictable' host-parasite system.

    PubMed

    Pérez-Del-Olmo, A; Montero, F E; Fernández, M; Barrett, J; Raga, J A; Kostadinova, A

    2010-10-01

    We address the effect of spatial scale and temporal variation on model generality when forming predictive models for fish assignment using a new data mining approach, Random Forests (RF), to variable biological markers (parasite community data). Models were implemented for a fish host-parasite system sampled along the Mediterranean and Atlantic coasts of Spain and were validated using independent datasets. We considered 2 basic classification problems in evaluating the importance of variations in parasite infracommunities for assignment of individual fish to their populations of origin: multiclass (2-5 population models, using 2 seasonal replicates from each of the populations) and 2-class task (using 4 seasonal replicates from 1 Atlantic and 1 Mediterranean population each). The main results are that (i) RF are well suited for multiclass population assignment using parasite communities in non-migratory fish; (ii) RF provide an efficient means for model cross-validation on the baseline data and this allows sample size limitations in parasite tag studies to be tackled effectively; (iii) the performance of RF is dependent on the complexity and spatial extent/configuration of the problem; and (iv) the development of predictive models is strongly influenced by seasonal change and this stresses the importance of both temporal replication and model validation in parasite tagging studies.

  8. Compensatory mechanisms in fish populations: Literature reviews: Volume 1, Critical evaluation of case histories of fish populations experiencing chronic exploitation or impact: Final report

    SciTech Connect

    Saila, S.B.; Chen, X.; Erzini, K.; Martin, B.

    1987-05-01

    This study includes case histories of certain fish species which are experiencing chronic perturbations and related literature pertaining to compensation processes. ''Compensation'' has been defined as the ability of fish to offset the population reduction caused by natural or man-induced stresses. Certain compensation methods are widely accepted, and include cannibalism, competition, disease, growth and predation, among others. These compensation methods are examined in relation to each fish species included in the study. Stock-recruit relationships and empirical observations of changes in growth and mortality have been the focus of much of the background on compensation. One of the conclusions drawn from this study is that a significant amount of recruitment variability exists and can be attributed to environmental (rather than compensatory) factors. The stock-recruitment problem appears to be the most significant scientific problem related to compensation in the types of fish included in this study. Results of the most recent studies of the American shad support this theory. Life histories, breeding biology and other pertinent data relating to each species included in the study will be found in the appendices.

  9. Patterns of connectivity among populations of a coral reef fish

    NASA Astrophysics Data System (ADS)

    Chittaro, P. M.; Hogan, J. D.

    2013-06-01

    Knowledge of the patterns and scale of connectivity among populations is essential for the effective management of species, but our understanding is still poor for marine species. We used otolith microchemistry of newly settled bicolor damselfish ( Stegastes partitus) in the Mesoamerican Reef System (MRS), Western Caribbean, to investigate patterns of connectivity among populations over 2 years. First, we assessed spatial and temporal variability in trace elemental concentrations from the otolith edge to make a `chemical map' of potential source reef(s) in the region. Significant otolith chemical differences were detected at three spatial scales (within-atoll, between-atolls, and region-wide), such that individuals were classified to locations with moderate (52 % jackknife classification) to high (99 %) accuracy. Most sites at Turneffe Atoll, Belize showed significant temporal variability in otolith concentrations on the scale of 1-2 months. Using a maximum likelihood approach, we estimated the natal source of larvae recruiting to reefs across the MRS by comparing `natal' chemical signatures from the otolith of recruits to the `chemical map' of potential source reef(s). Our results indicated that populations at both Turneffe Atoll and Banco Chinchorro supply a substantial amount of individuals to their own reefs (i.e., self-recruitment) and thus emphasize that marine conservation and management in the MRS region would benefit from localized management efforts as well as international cooperation.

  10. The Prevalence of Tooth Wear in the Dutch Adult Population

    PubMed Central

    Wetselaar, Peter; Vermaire, Jan H.; Visscher, Corine M.; Lobbezoo, Frank; Schuller, Annemarie A.

    2016-01-01

    This study aimed to assess the prevalence of tooth wear in different age groups of the Dutch adult population and to determine this tooth wear distribution by gender, socioeconomic class, and type of teeth. Results were compared with the outcomes of a previous study in a comparable population. As part of a comprehensive investigation of the oral health of the general Dutch adult population in 2013, tooth wear was assessed among 1,125 subjects in the city of ‘s-Hertogenbosch. The data collected were subjected to stratified analysis by 5 age groups (25-34, 35-44, 45-54, 55-64, and 65-74 years), gender, socioeconomic class, and type of teeth. Tooth wear was assessed using a 5-point ordinal occlusal/incisal grading scale. The number of teeth affected was higher in older age groups. Men showed more tooth wear than women, and subjects with low socioeconomic status (low SES) showed on average higher scores than those with high SES. Tooth wear prevalence found in this study was higher in all age groups than in the previous study. The present study found prevalences of 13% for mild tooth wear and 80% for moderate tooth wear, leading to the conclusion that these are common conditions in the Dutch adult population. Severe tooth wear (prevalence 6%) may however be characterized as rare. A tendency was found for there to be more tooth wear in older age groups, in men as compared with women, in persons with lower SES, and in the present survey as compared with the previous one. PMID:27694757

  11. Tuning stochastic matrix models with hydrologic data to predict the population dynamics of a riverine fish

    USGS Publications Warehouse

    Sakaris, P.C.; Irwin, E.R.

    2010-01-01

    We developed stochastic matrix models to evaluate the effects of hydrologic alteration and variable mortality on the population dynamics of a lotie fish in a regulated river system. Models were applied to a representative lotic fish species, the flathead catfish (Pylodictis olivaris), for which two populations were examined: a native population from a regulated reach of the Coosa River (Alabama, USA) and an introduced population from an unregulated section of the Ocmulgee River (Georgia, USA). Size-classified matrix models were constructed for both populations, and residuals from catch-curve regressions were used as indices of year class strength (i.e., recruitment). A multiple regression model indicated that recruitment of flathead catfish in the Coosa River was positively related to the frequency of spring pulses between 283 and 566 m3/s. For the Ocmulgee River population, multiple regression models indicated that year class strength was negatively related to mean March discharge and positively related to June low flow. When the Coosa population was modeled to experience five consecutive years of favorable hydrologic conditions during a 50-year projection period, it exhibited a substantial spike in size and increased at an overall 0.2% annual rate. When modeled to experience five years of unfavorable hydrologic conditions, the Coosa population initially exhibited a decrease in size but later stabilized and increased at a 0.4% annual rate following the decline. When the Ocmulgee River population was modeled to experience five years of favorable conditions, it exhibited a substantial spike in size and increased at an overall 0.4% annual rate. After the Ocmulgee population experienced five years of unfavorable conditions, a sharp decline in population size was predicted. However, the population quickly recovered, with population size increasing at a 0.3% annual rate following the decline. In general, stochastic population growth in the Ocmulgee River was more

  12. Morphometric Evaluation of Adult Acromion Process in North Indian Population

    PubMed Central

    Vasudeva, Neelam

    2017-01-01

    Introduction Dimensions of acromion process are important to show linkage to the shoulder girdle pathologies. Also morphometric analysis of acromion process would be helpful for surgeons while performing surgical procedures on the shoulder joint. Aim The purpose of this present study was to observe the detailed morphometric evaluation of adult acromion processes in North Indian population because different morphometric dimensions play an important role in various disorders of the shoulder, particularly sub acromial impingement syndrome. Materials and Methods Two hundred adult dry scapulae from the osteology museum of MAMC, New Delhi, were obtained for evaluation of various measurement of acromion process. The length, width, thickness of acromion, coraco-acromial (C-A) distance and acromio-glenoid (Ac-g) distance were measured. The measurements were compared with other osteological studies performed on different population group. Data was analysed using SPSS version 12.0 and mean values with standard deviation for each dimension were presented. Results The mean values of each measurement were: length: 41.007 mm; width: 21.82 mm; thickness: 6.58 mm; C-A distance: 28.34 mm and Ac-g distance: 26.21 mm. Conclusion It is expected that various dimensions of adult acromion process will serve as a reference base and will assist the surgeon in the approach to be used and precision of the operative technique. So, the study will provide a vital support for planning and executing acromioplasty in the treatment of impingement syndrome. PMID:28273959

  13. The influence of density on adults and juveniles of the estuarine fish, the sheepshead minnow (cyprinodon variegatus)

    EPA Science Inventory

    The relationship between population density and demographic rates (e.g. survival, reproduction, growth) is critical to understand population dynamics and has been widely studied in fishes. Estuarine species are regularly exposed to dramatic changes in density with daily, monthly,...

  14. Prevalence and Population Structure of Vibrio vulnificus on Fishes from the Northern Gulf of Mexico

    PubMed Central

    Tao, Zhen; Larsen, Andrea M.; Bullard, Stephen A.; Wright, Anita C.

    2012-01-01

    The prevalence of Vibrio vulnificus on the external surfaces of fish from the northern Gulf of Mexico was determined in this study. A collection of 242 fish comprising 28 species was analyzed during the course of 12 sampling trips over a 16-month period. The prevalence of V. vulnificus was 37% but increased up to 69% in summer. A positive correlation was found between the percentages of V. vulnificus-positive fish and water temperatures, while salinity and V. vulnificus-positive fish prevalence were inversely correlated. A general lineal model (percent V. vulnificus-positive fish = 0.5930 − 0.02818 × salinity + 0.01406 × water temperature) was applied to best fit the data. Analysis of the population structure was carried out using 244 isolates recovered from fish. Ascription to 16S rRNA gene types indicated that 157 isolates were type A (62%), 72 (29%) were type B, and 22 (9%) were type AB. The percentage of type B isolates, considered to have greater virulence potential, was higher than that previously reported in oyster samples from the northern Gulf of Mexico. Amplified fragment length polymorphism (AFLP) was used to resolve the genetic diversity within the species. One hundred twenty-one unique AFLP profiles were found among all analyzed isolates, resulting in a calculated Simpson's index of diversity of 0.991. AFLP profiles were not grouped on the basis of collection date, fish species, temperature, or salinity, but isolates were clustered into two main groups that correlated precisely with 16S rRNA gene type. The population of V. vulnificus associated with fishes from the northern Gulf of Mexico is heterogeneous and includes strains of great virulence potential. PMID:22923394

  15. Prevalence and population structure of Vibrio vulnificus on fishes from the northern Gulf of Mexico.

    PubMed

    Tao, Zhen; Larsen, Andrea M; Bullard, Stephen A; Wright, Anita C; Arias, Covadonga R

    2012-11-01

    The prevalence of Vibrio vulnificus on the external surfaces of fish from the northern Gulf of Mexico was determined in this study. A collection of 242 fish comprising 28 species was analyzed during the course of 12 sampling trips over a 16-month period. The prevalence of V. vulnificus was 37% but increased up to 69% in summer. A positive correlation was found between the percentages of V. vulnificus-positive fish and water temperatures, while salinity and V. vulnificus-positive fish prevalence were inversely correlated. A general lineal model (percent V. vulnificus-positive fish = 0.5930 - 0.02818 × salinity + 0.01406 × water temperature) was applied to best fit the data. Analysis of the population structure was carried out using 244 isolates recovered from fish. Ascription to 16S rRNA gene types indicated that 157 isolates were type A (62%), 72 (29%) were type B, and 22 (9%) were type AB. The percentage of type B isolates, considered to have greater virulence potential, was higher than that previously reported in oyster samples from the northern Gulf of Mexico. Amplified fragment length polymorphism (AFLP) was used to resolve the genetic diversity within the species. One hundred twenty-one unique AFLP profiles were found among all analyzed isolates, resulting in a calculated Simpson's index of diversity of 0.991. AFLP profiles were not grouped on the basis of collection date, fish species, temperature, or salinity, but isolates were clustered into two main groups that correlated precisely with 16S rRNA gene type. The population of V. vulnificus associated with fishes from the northern Gulf of Mexico is heterogeneous and includes strains of great virulence potential.

  16. Nightmares: Risk Factors Among the Finnish General Adult Population

    PubMed Central

    Sandman, Nils; Valli, Katja; Kronholm, Erkki; Revonsuo, Antti; Laatikainen, Tiina; Paunio, Tiina

    2015-01-01

    Study Objectives: To identify risk factors for experiencing nightmares among the Finnish general adult population. The study aimed to both test whether previously reported correlates of frequent nightmares could be reproduced in a large population sample and to explore previously unreported associations. Design: Two independent cross-sectional population surveys of the National FINRISK Study. Setting: Age- and sex-stratified random samples of the Finnish population in 2007 and 2012. Participants: A total of 13,922 participants (6,515 men and 7,407 women) aged 25–74 y. Interventions: N/A. Measurements and results: Nightmare frequency as well as several items related to socioeconomic status, sleep, mental well-being, life satisfaction, alcohol use, medication, and physical well-being were recorded with a questionnaire. In multinomial logistic regression analysis, a depression-related negative attitude toward the self (odds ratio [OR] 1.32 per 1-point increase), insomnia (OR 6.90), and exhaustion and fatigue (OR 6.86) were the strongest risk factors for experiencing frequent nightmares (P < 0.001 for all). Sex, age, a self-reported impaired ability to work, low life satisfaction, the use of antidepressants or hypnotics, and frequent heavy use of alcohol were also strongly associated with frequent nightmares (P < 0.001 for all). Conclusions: Symptoms of depression and insomnia were the strongest predictors of frequent nightmares in this dataset. Additionally, a wide variety of factors related to psychological and physical well-being were associated with nightmare frequency with modest effect sizes. Hence, nightmare frequency appears to have a strong connection with sleep and mood problems, but is also associated with a variety of measures of psychological and physical well-being. Citation: Sandman N, Valli K, Kronholm E, Revonsuo A, Laatikainen T, Paunio T. Nightmares: risk factors among the finnish general adult population. SLEEP 2015;38(4):507–514. PMID:25325474

  17. Environmental Assessment: Lake Yankton Fish Population Renovation Project Yankton County, South Dakota and Cedar County, Nebraska

    DTIC Science & Technology

    2014-08-01

    mussels are known to exist in Lake Yankton. Western Prairie Fringed Orchid (Platanthera praeclara) No Affect. The western prairie fringed orchid is...a species of the North American tallgrass prairie community. Western prairie fringed orchid populations have declined significantly throughout... orchid habitat is known to occur near Lake Yankton. Lake Yankton Fish Population Renovation Project U.S. Army Corps of Engineers August 2014 3-11 Omaha

  18. ECOLOGICAL ENDPOINT MODELING FOR TMDLS: EFFECTS OF SEDIMENT ON FISH POPULATIONS

    EPA Science Inventory

    Sediment is one of the primary stressors of concern for Total Maximum Daily Loads (TMDLs) for streams, and often it is a concern because of its impact on ecological endpoints. A modeling approach relating sediment to stream fish population dynamics is presented. Equations are d...

  19. VARIATION IN RESPONSIVENESS TO CONTAMINANTS IN WILD POPULATIONS OF ESTUARINE FISH, FUNDULUS HETERCLITUS

    EPA Science Inventory

    Populations of the non-migratory estuarine fish species Fundulus heteroclitus indigenous to a PCB-contaminated Superfund site (New Bedford Harbor, MA, USA) are markedly less sensitive to the toxic effects of local contaminants than those from a reference site. We characterized th...

  20. Flow management and fish density regulate salmonid recruitment and adult size in tailwaters across western North America.

    PubMed

    Dibble, Kimberly L; Yackulic, Charles B; Kennedy, Theodore A; Budy, Phaedra

    2015-12-01

    Rainbow and brown trout have been intentionally introduced into tailwaters downriver of dams globally and provide billions of dollars in economic benefits. At the same time, recruitment and maximum length of trout populations in tailwaters often fluctuate erratically, which negatively affects the value of fisheries. Large recruitment events may increase dispersal downriver where other fish species may be a priority (e.g., endangered species). There is an urgent need to understand the drivers of trout population dynamics in tailwaters, in particular the role of flow management. Here, we evaluate how flow, fish density, and other physical factors of the river influence recruitment and mean adult length in tailwaters across western North America, using data from 29 dams spanning 1-19 years. Rainbow trout recruitment was negatively correlated with high annual, summer, and spring flow and dam latitude, and positively correlated with high winter flow, subadult brown trout catch, and reservoir storage capacity. Brown trout recruitment was negatively correlated with high water velocity and daily fluctuations in flow (i.e., hydropeaking) and positively correlated with adult rainbow trout catch. Among these many drivers, rainbow trout recruitment was primarily correlated with high winter flow combined with low spring flow, whereas brown trout recruitment was most related to high water velocity. The mean lengths of adult rainbow and brown trout were influenced by similar flow and catch metrics. Length in both species was positively correlated with high annual flow but declined in tailwaters with high daily fluctuations in flow, high catch rates of conspecifics, and when large cohorts recruited to adult size. Whereas brown trout did not respond to the proportion of water allocated between seasons, rainbow trout length increased in rivers that released more water during winter than in spring. Rainbow trout length was primarily related to high catch rates of conspecifics

  1. Stabilization of population fluctuations due to cannibalism promotes resource polymorphism in fish.

    PubMed

    Andersson, Jens; Bystrom, Par; Claessen, David; Persson, Lennart; De Roos, Andre M

    2007-06-01

    Resource polymorphism is a well-known phenomenon in many taxa, assumed to be a consequence of strong competition for resources and to be facilitated by stable environments and the presence of several profitable resources on which to specialize. In fish, resource polymorphism, in the form of planktivore-benthivore pairs, is found in a number of species. We gathered literature data on life-history characteristics and population dynamics for 15 fish species and investigated factors related to the presence of such resource polymorphism. This investigation indicated that early cannibalism and low overall population variability are typically associated with the presence of resource polymorphism. These findings match previously reported patterns of population dynamics for size-structured fish populations, whereby early cannibalism has been shown to decrease temporal variation in population dynamics and to equalize the profitability of the zooplankton and macroinvertebrate resources. Our study suggests that competition alone is not a sufficient condition for the development of resource polymorphism because overly strong competition is typically associated with increased temporal variation (environmental instability). We conclude that although resource competition is an important factor regulating the development of resource polymorphism, cannibalism may also play a fundamental role by dampening population oscillations and possibly by equalizing the profitability of different resources.

  2. Educating and Training out of Poverty? Adult Provision and the Informal Sector in Fishing Communities, South Africa

    ERIC Educational Resources Information Center

    Petersen, Carolyn

    2007-01-01

    This paper looks at access to adult education and vocational education and training (VET) provision in fishing communities in the Western Cape, South Africa. Fishing communities are being disadvantaged due to geographical and socio-political marginalisation, and the predominance of informal sector employment in the context of worldwide marine…

  3. Population persistence of stream fish in response to environmental change: integrating data and models across space

    NASA Astrophysics Data System (ADS)

    Letcher, B. H.; Schueller, P.; Bassar, R.; Coombs, J.; Rosner, A.; Sakrejda, K.; Kanno, Y.; Whiteley, A.; Nislow, K. H.

    2013-12-01

    For stream fishes, environmental variation is a key driver of individual body growth/movement/survival and, by extension, population dynamics. Identifying how stream fish respond to environmental variation can help clarify mechanisms responsible for population dynamics and can help provide tools to forecast relative resilience of populations across space. Forecasting dynamics across space is challenging, however, because it can be difficult to conduct enough studies with enough intensity to fully characterize broad-scale population response to environmental change. We have adopted a multi-scale approach, using detailed individual-based studies and analyses (integral projection matrix) to determine sensitivities of population growth to environmental variation combined with broad spatial data and analyses (occupancy and abundance models) to estimate patterns of population response across space. Population growth of brook trout was most sensitive to stream flow in the spring and winter, most sensitive to stream temperature in the fall and sensitive to both flow and temperature in the summer. High flow in the spring and winter had negative effects on population growth while high temperature had a negative effect in the fall. Flow had no effect when it was cold, but a positive effect when it was warm in the summer. Combined with occupancy and abundance models, these data give insight into the spatial structure of resilient populations and can help guide prioritization of management actions.

  4. Some aspects of the taxonomy and biology of adult spirurine nematodes parasitic in fishes: a review.

    PubMed

    Moravec, Frantisek

    2007-11-01

    About 300 species belonging to four superfamilies (Gnathostomatoidea, Habronematoidea, Physalopteroidea and Thelazioidea) of the nematode suborder Spirurina are known as the adult parasites of freshwater, brackish-water and marine fishes. They are placed in four families, of which the Gnathostomatidae, including Echinocephalus with a few species and the monotypic Metaleptus, are parasites of elasmobranchs, whereas Ancyracanthus contains one species in teleosts; the Physalopteridae is represented in fish by four genera, Bulbocephalus, Heliconema, Paraleptus and Proleptus, each with several species in both elasmobranchs and teleosts. The majority of fish spirurines belongs to the Rhabdochonidae, which includes 10 genera (Beaninema, Fellicola, Hepatinema, Heptochona, Johnstonmawsonia, Megachona, Pancreatonema, Prosungulonema, Rhabdochona and Vasorhabdochona) of species parasitizing mainly teleosts, rarely elasmobranchs, and the Cystidicolidae with about 23 genera (Ascarophis, Caballeronema, Capillospirura, Comephoronema, Crenatobronema, Cristitectus, Ctenascarophis, Cyclozone, Cystidicola, Cystidicoloides, Johnstonmawsonoides, Metabronema, Moravecnema, Neoascarophis, Parascarophis, Prospinitectus, Pseudascarophis, Pseudoproleptus, Salvelinema, Similascarophis, Spinitectoides, Spinitectus, Sterliadochona), with many species parasitic in teleosts only. Because of difficulties in studying fish spirurines, associated with their morphological and biological peculiarities, most species of these parasites are poorly known. It is apparent that their present classification system does not reflect phylogenetic relationships and a taxonomic revision of this nematode group, based on detailed morphological (including SEM and TEM), life history and molecular studies of individual species, is quite necessary. In Cystidicolidae, several genera have been based on details in the cephalic structures visible only with the aid of SEM, but it will be evident whether or not these tiny

  5. Observations of migrant exchange and mixing in a coral reef fish metapopulation link scales of marine population connectivity.

    PubMed

    Horne, John B; van Herwerden, Lynne; Abellana, Sheena; McIlwain, Jennifer L

    2013-01-01

    Much progress has been made toward understanding marine metapopulation dynamics, largely because of multilocus microsatellite surveys able to connect related individuals within the metapopulation. However, most studies are focused on small spatial scales, tens of kilometers, while demographic exchange at larger spatial scales remains poorly documented. Additionally, many small-scale demographic studies conflict with broad-scale phylogeographic patterns concerning levels of marine population connectivity, highlighting a need for data on more intermediate scales. Here, we investigated demographic recruitment processes of a commercially important coral reef fish, the bluespine unicornfish (Naso unicornis) using a suite of mitochondrial DNA (mtDNA) and microsatellite markers. Sampling for this study ranged across the southern Marianas Islands, a linear distance of 250 km and included 386 newly settled postlarval recruits. In contrast with other studies, we report that cohorts of recruits were genetically homogeneous in space and time, with no evidence of temporally stochastic sweepstakes reproduction. The genetic diversity of recruits was high and commensurate with that of the adult population. In addition, there is substantial evidence that 2 recruits, separated by 250 km, were full siblings. This is the largest direct observation of dispersal to date for a coral reef fish. All indications suggest that subpopulations of N. unicornis experience high levels of demographic migrant exchange and metapopulation mixing on a spatial scale of hundreds of kilometers, consistent with high levels of broad-scale genetic connectivity previously reported in this species.

  6. Functional significance of mononuclear phagocyte populations generated through adult hematopoiesis

    PubMed Central

    Gutknecht, Michael F.; Bouton, Amy H.

    2014-01-01

    Tissue homeostasis requires a complete repertoire of functional macrophages in peripheral tissues. Recent evidence indicates that many resident tissue macrophages are seeded during embryonic development and persist through adulthood as a consequence of localized proliferation. Mononuclear phagocytes are also produced during adult hematopoiesis; these cells are then recruited to sites throughout the body, where they function in tissue repair and remodeling, resolution of inflammation, maintenance of homeostasis, and disease progression. The focus of this review is on mononuclear phagocytes that comprise the nonresident monocyte/macrophage populations in the body. Key features of monocyte differentiation are presented, focusing primarily on the developmental hierarchy that is established through this process, the markers used to identify discrete cell populations, and novel, functional attributes of these cells. These features are then explored in the context of the tumor microenvironment, where mononuclear phagocytes exhibit extensive plasticity in phenotype and function. PMID:25225678

  7. Trophic status and helminth infracommunities of fish populations in Kashmir Himalayan lakes.

    PubMed

    Shah, H B; Yousuf, A R; Chishti, M Z; Shahnaz, S; Ahmad, F

    2014-09-01

    The present study considers the influence of the trophic status of three Kashmir Himalayan lakes on the patterns of helminth infracommunities in populations of three species of fish during 2006 to 2008. Data were collected from three lakes of differing trophic status in the Kashmir Himalayas, namely Anchar, a hyper(eu)trophic lake; Dal, a eutrophic lake; and Manasbal, a meso(eu)trophic lake. Three species of fish examined included the native fish Schizothorax niger Heckel and two exotic species--Carassius carassius (Linnaeus) and Cyprinus carpio Linnaeus. The analysis of data showed a clear habitat effect on the abundance pattern of helminth species, thus revealing lake-specific differences in parasite infracommunities of both S. niger and C. carassius. Helminth infracommunity richness was the highest in host populations from the Anchar lake compared to other two lakes. Low values in the Manasbal lake emphasize the low diversity of their helminth infracommunities. On the other hand, there was no observed pattern of community structure in the case of C. carpio in the three lake sites. However due to bias in sampling there was no distinct effect of fish body size on parasite infracommunity structure, although the present results do show that fish parasite data can be meaningful in diagnosing changes in the trophic condition of eutrophic lakes.

  8. Fish populations associated with habitat-modified piers and natural woody debris in Piedmont Carolina reservoirs

    USGS Publications Warehouse

    Barwick, R.D.; Kwak, T.J.; Noble, R.L.; Barwick, D.H.

    2004-01-01

    A primary concern associated with reservoir shoreline residential development is reduction of littoral habitat complexity and diversity. One potential approach to compensate for this is the deployment of artificial-habitat modules under existing piers, but the benefit of this practice has not been demonstrated. To evaluate the effect of pier habitat modifications on fish populations in two Piedmont Carolina reservoirs, we studied 77 piers located on forty-seven, 100-m transects that were modified using plastic "fish hab" modules augmented with brush (brushed habs), hab modules alone (habs), or left unaltered for reference purposes. We sampled fish from all piers and transects during April, July, and October 2001 using a boat-mounted electrofisher. With few exceptions, catch rates were higher at brushed-hab piers and piers with habs than at reference piers during all seasons. Similarly, during spring and summer, fish abundance was generally higher on transects containing natural woody debris, brushed habs, and habs than on reference-developed transects; however, during fall, there were exceptions. Therefore, fish abundance associated with shorelines in these reservoirs appears to be related to the structural complexity of available habitat rather than structure composition. One year after installation, 92% of pier owners responding to a mail survey expressed satisfaction with pier modifications. Supplementing piers with habitat structures is recommended to enhance littoral habitat complexity for fishes in residentially developed reservoirs.

  9. Contrasting environmental drivers of adult and juvenile growth in a marine fish: implications for the effects of climate change

    PubMed Central

    Ong, Joyce Jia Lin; Nicholas Rountrey, Adam; Jane Meeuwig, Jessica; John Newman, Stephen; Zinke, Jens; Gregory Meekan, Mark

    2015-01-01

    Many marine fishes have life history strategies that involve ontogenetic changes in the use of coastal habitats. Such ontogenetic shifts may place these species at particular risk from climate change, because the successive environments they inhabit can differ in the type, frequency and severity of changes related to global warming. We used a dendrochronology approach to examine the physical and biological drivers of growth of adult and juvenile mangrove jack (Lutjanus argentimaculatus) from tropical north-western Australia. Juveniles of this species inhabit estuarine environments and adults reside on coastal reefs. The Niño-4 index, a measure of the status of the El Niño-Southern Oscillation (ENSO) had the highest correlation with adult growth chronologies, with La Niña years (characterised by warmer temperatures and lower salinities) having positive impacts on growth. Atmospheric and oceanographic phenomena operating at ocean-basin scales seem to be important correlates of the processes driving growth in local coastal habitats. Conversely, terrestrial factors influencing precipitation and river runoff were positively correlated with the growth of juveniles in estuaries. Our results show that the impacts of climate change on these two life history stages are likely to be different, with implications for resilience and management of populations. PMID:26052896

  10. Contrasting environmental drivers of adult and juvenile growth in a marine fish: implications for the effects of climate change.

    PubMed

    Ong, Joyce Jia Lin; Rountrey, Adam Nicholas; Meeuwig, Jessica Jane; Newman, Stephen John; Zinke, Jens; Meekan, Mark Gregory

    2015-06-08

    Many marine fishes have life history strategies that involve ontogenetic changes in the use of coastal habitats. Such ontogenetic shifts may place these species at particular risk from climate change, because the successive environments they inhabit can differ in the type, frequency and severity of changes related to global warming. We used a dendrochronology approach to examine the physical and biological drivers of growth of adult and juvenile mangrove jack (Lutjanus argentimaculatus) from tropical north-western Australia. Juveniles of this species inhabit estuarine environments and adults reside on coastal reefs. The Niño-4 index, a measure of the status of the El Niño-Southern Oscillation (ENSO) had the highest correlation with adult growth chronologies, with La Niña years (characterised by warmer temperatures and lower salinities) having positive impacts on growth. Atmospheric and oceanographic phenomena operating at ocean-basin scales seem to be important correlates of the processes driving growth in local coastal habitats. Conversely, terrestrial factors influencing precipitation and river runoff were positively correlated with the growth of juveniles in estuaries. Our results show that the impacts of climate change on these two life history stages are likely to be different, with implications for resilience and management of populations.

  11. Fish population studies using parasites from the Southeastern Pacific Ocean: considering host population changes and species body size as sources of variability of parasite communities.

    PubMed

    George-Nascimento, Mario; Oliva, Marcelo

    2015-01-01

    Research using parasites in fish population studies in the South Eastern Pacific (SEP) is summarized. There are 27 such studies (snapshots mainly) in single host species sampled at different geographic localities and at somewhat similar times. They have been devoted mainly to economically important species, though others on coastal and intertidal fish or on less- or non-commercial species provide insights on scales of temporal and spatial variation of parasite infracommunities. Later, we assess whether the probability of harbouring parasites depends on the host species body size. Our results indicate that a stronger tool for fish population studies may be developed under regular (long term) scrutiny of parasite communities, especially of small fish host species, due to their larger variability in richness, abundance and total biomass, than in large fish species. Finally, it might also be necessary to consider the effects of fishing on parasite communities as well as the natural oscillations (coupled or not) of host and parasite populations.

  12. Serum concentrations of perfluorinated compounds (PFC) among selected populations of children and Adults in California

    PubMed Central

    Wu, Xiangmei (May); Bennett, Deborah H.; Calafat, Antonia M.; Kato, Kayoko; Strynar, Mark; Andersen, Erik; Moran, Rebecca E.; Tancredi, Daniel J.; Tulve, Nicolle S.; Hertz-Picciotto, Irva

    2016-01-01

    Perfluorinated compounds (PFCs) have been widely used in industrial applications and consumer products. Their persistent nature and potential health impacts are of concern. Given the high cost of collecting serum samples, this study is to understand whether we can quantify PFC serum concentrations using factors extracted from questionnaire responses and indirect measurements, and whether a single serum measurement can be used to classify an individual’s exposure over a one-year period. The study population included three demographic groups: young children (2–8 years old) (N=67), parents of young children (<55 years old) (N=90), and older adults (>55 years old) (N=59). PFC serum concentrations, house dust concentrations, and questionnaires were collected. The geometric mean of perfluorooctane sulfonic acid (PFOS) was highest for the older adults. In contrast, the geometric mean of perfluorooctanoic acid (PFOA) was highest for children. Serum concentrations of the parent and the child from the same family were moderately correlated (Spearman correlation (r)=0.26–0.79, p<0.05), indicating common sources within a family. For adults, age, having occupational exposure or having used fire extinguisher, frequencies of consuming butter/margarine, pork, canned meat entrées, tuna and white fish, freshwater fish, and whether they ate microwave popcorn were significantly positively associated with serum concentrations of individual PFCs. For children, residential dust concentrations, frequency of wearing waterproof clothes, frequency of having canned fish, hotdogs, chicken nuggets, French fries, and chips, and whether they ate microwave popcorn were significant positive predictors of individual PFC serum concentrations. In addition, the serum concentrations collected in a subset of young children (N=20) and the parents (N=42) one year later were strongly correlated (r=0.68–0.98, p<0.001) with the levels measured at the first visits, but showed a decreasing trend

  13. Importance of the habitat choice behavior assumed when modeling the effects of food and temperature on fish populations

    USGS Publications Warehouse

    Wildhaber, Mark L.; Lamberson, Peter J.

    2004-01-01

    Various mechanisms of habitat choice in fishes based on food and/or temperature have been proposed: optimal foraging for food alone; behavioral thermoregulation for temperature alone; and behavioral energetics and discounted matching for food and temperature combined. Along with development of habitat choice mechanisms, there has been a major push to develop and apply to fish populations individual-based models that incorporate various forms of these mechanisms. However, it is not known how the wide variation in observed and hypothesized mechanisms of fish habitat choice could alter fish population predictions (e.g. growth, size distributions, etc.). We used spatially explicit, individual-based modeling to compare predicted fish populations using different submodels of patch choice behavior under various food and temperature distributions. We compared predicted growth, temperature experience, food consumption, and final spatial distribution using the different models. Our results demonstrated that the habitat choice mechanism assumed in fish population modeling simulations was critical to predictions of fish distribution and growth rates. Hence, resource managers who use modeling results to predict fish population trends should be very aware of and understand the underlying patch choice mechanisms used in their models to assure that those mechanisms correctly represent the fish populations being modeled.

  14. Trematode infection causes malformations and population effects in a declining New Zealand fish.

    PubMed

    Kelly, David W; Thomas, Harriet; Thieltges, David W; Poulin, Robert; Tompkins, Daniel M

    2010-03-01

    1. Animal malformations engender wide public and scientific concern because of associated environmental health risks. This is highlighted by increased incidence of limb malformations in amphibians associated with trematode infections and disturbance. Malformations may signal new emerging disease threats, but whether the phenomenon is broadly applicable across taxa, or has population-scale impacts, is unknown. 2. Malformations are widely reported in fish and, until now, have been attributed mainly to contaminants. We tested whether the trematode Telogaster opisthorchis caused severe malformations, leading to population effects, in Galaxias anomalus, a threatened New Zealand freshwater fish. 3. Experimental infection of larval fish caused increasing spinal malformation and mortality with infection intensity that closely matched field patterns. Field malformation frequency peaked in January (65%), before declining sharply in February (25%) and remaining low thereafter. 4. The peak occurred during a 'critical window' of larval development, with the decline coincident with a population crash, indicating that malformation was causing mortality in the field. 5. The occurrence of such critical developmental windows may explain why this mechanism of population impact has been overlooked. With global environmental stressors predicted to enhance trematode infections, our results show that parasite-induced malformation, and its population-scale impacts, could be more widespread than previously considered.

  15. Impact of climate change on fish population dynamics in the Baltic sea: a dynamical downscaling investigation.

    PubMed

    Mackenzie, Brian R; Meier, H E Markus; Lindegren, Martin; Neuenfeldt, Stefan; Eero, Margit; Blenckner, Thorsten; Tomczak, Maciej T; Niiranen, Susa

    2012-09-01

    Understanding how climate change, exploitation and eutrophication will affect populations and ecosystems of the Baltic Sea can be facilitated with models which realistically combine these forcings into common frameworks. Here, we evaluate sensitivity of fish recruitment and population dynamics to past and future environmental forcings provided by three ocean-biogeochemical models of the Baltic Sea. Modeled temperature explained nearly as much variability in reproductive success of sprat (Sprattus sprattus; Clupeidae) as measured temperatures during 1973-2005, and both the spawner biomass and the temperature have influenced recruitment for at least 50 years. The three Baltic Sea models estimate relatively similar developments (increases) in biomass and fishery yield during twenty-first century climate change (ca. 28 % range among models). However, this uncertainty is exceeded by the one associated with the fish population model, and by the source of global climate data used by regional models. Knowledge of processes and biases could reduce these uncertainties.

  16. Applying population genetics for authentication of marine fish: the case of saithe (Pollachius virens).

    PubMed

    Behrmann, Konstanze; Rehbein, Hartmut; von Appen, Annika; Fischer, Markus

    2015-01-28

    The number of fishery products with a quite detailed description of the origin is increasing. This trend is driven by the interest of consumers and the fight against illegal unregulated and unreported fisheries. Unfortunately, there is a lack of methods to prove this information experimentally besides the document-based traceability assessments. For marine fish population genetics is a promising strategy, but research is concentrated only on a few species. Saithe is a commercially important fish species, despite the fact that genetic knowledge is scarce regarding the specification of populations. For a comparative study cost- and time-effective strategies were tested: We found RAPD-PCR to be a useful method for low-budget research or prestudies. Adoption of microsatellites from closely related species turned out to be possible with limited success quota. Our results suggest a clustered structure of populations within the Northeast Atlantic, probably overlapping in the northern North Sea.

  17. [Alimentation dependent health disorders among adult population of Bashkortostan Republic and their relation with nutritional traits].

    PubMed

    Takaev, R M; Kondrova, N S; Baĭkina, I M; Larionova, T K

    2008-01-01

    The authors demonstrated relationship between alimentation dependent diseases among adult population of the Republic and nutritional traits of the population, defined major directions of program to optimize nutrition of the population.

  18. Biodiversity, population regulation, and the stability of coral-reef fish communities

    PubMed Central

    Carr, Mark H.; Anderson, Todd W.; Hixon, Mark A.

    2002-01-01

    Unprecedented population declines and extinctions because of human activities, combined with a growing recognition that such losses affect the stability of ecosystems, underscore the need to better understand how populations persist naturally. We provide field experimental evidence that high biodiversity—in particular, the combined effects of predators and competitors—acts in a way that regulates the size of local fish populations within their coral-reef community. These results indicate that complex interactions among multiple species are necessary for the stability of a highly diverse community, and so forewarn that overexploiting such species may have cascading negative consequences for the entire system. PMID:12177430

  19. Predictors of Septic Arthritis in the Adult Population.

    PubMed

    Borzio, Robert; Mulchandani, Neil; Pivec, Robert; Kapadia, Bhaveen H; Leven, Dante; Harwin, Steven F; Urban, William P

    2016-07-01

    Septic arthritis is a devastating condition; well-established criteria for diagnosis exist in the pediatric population, but not for adults. This study evaluated patient factors and laboratory parameters that may be associated with the diagnosis of septic arthritis in adults. A total of 458 knee aspirates for suspected septic arthritis were evaluated with serum and synovial leukocyte counts and differentials as well as Kocher criteria for pediatric septic arthritis. Twenty-two patients (4.8%) had septic arthritis confirmed by a positive synovial fluid culture. Erythrocyte sedimentation rate (ESR) and serum white blood cell (WBC) counts were not statistically different between the 2 groups, with 64% of septic arthritis patients having a normal serum WBC count and 77% being afebrile. Mean synovial fluid WBC count was 26,758 cells/µL and 70,581 cells/µL in the nonseptic and septic groups, respectively. The likelihood ratio for a synovial fluid WBC count greater than 65,000 cells/µL was 2.8 (95% confidence interval, 1.2-6.7). Evaluation receiver operating characteristic curves using synovial WBC counts resulted in a significant area under the curve of 0.66 (P=.02). To achieve 90% specificity, a WBC cutoff of 64,000 cells/µL was required with a corresponding sensitivity of 40%. There was no significant difference in the synovial cell differential of 80% vs 90% in diagnosing infection. Synovial fluid WBC count greater than 64,000 cells/µL yielded the optimal combination of sensitivity and specificity. Polymorphonuclear leukocytes, ESR, serum WBC count, fever, and weight-bearing status were not significant predictors of septic arthritis. This study demonstrates the limited utility of Kocher criteria in the adult population and the importance of synovial leukocyte counts. [Orthopedics. 2016; 39(4):e657-e663.].

  20. Fish (Fundulus heteroclitus) populations with different exposure histories differ in tolerance of creosote-contaminated sediments.

    PubMed

    Ownby, David R; Newman, Michael C; Mulvey, Margaret; Vogelbein, Wolfgang K; Unger, Michael A; Arzayus, L Felipe

    2002-09-01

    Prior studies suggest that field-collected fish (Fundulus heteroclitus) from a creosote-contaminated Superfund site (Atlantic Wood Industries site, Elizabeth River, VA, USA) have enhanced tolerance to local, contaminated sediments. This study was designed to test whether other populations in the Elizabeth River at less contaminated sites also show similar tolerance and whether this tolerance is heritable. To test this, F. heteroclitus populations were sampled from four sites within the Elizabeth River with varying sediment polycyclic aromatic hydrocarbon (PAH) concentrations (3.9-264 ng PAH/g dry wt 10(3)) and one reference site in a nearby, uncontaminated estuary (York River, VA, USA; 0.27 ng PAH/g dry wt x 10(3)). Embryo assays were performed to quantify population differences in teratogenic effects during contaminated sediment exposure. Atlantic Wood sediment was mixed with reference sediment to achieve a range of sediment concentrations. Minimal differences were observed in teratogenic effects among fish taken from sites within the Elizabeth River; however, embryos of fish collected from a nearby, uncontaminated York River site and exposed to contaminated sediments had a significantly higher proportion of embryos with cardiac abnormalities than those from the Elizabeth River sites. Embryos from wild-caught and laboratory-reared Elizabeth River F. heteroclitus were simultaneously exposed to contaminated sediments, and no significant tolerance differences were found between embryos from fish taken directly from the field and those reared for a generation in the lab. Differences between fish populations from the two estuaries were larger than differences within the Elizabeth River, and these differences in tolerance were heritable.

  1. Populations of a cyprinid fish are self-sustaining despite widespread feminization of males

    PubMed Central

    2014-01-01

    Background Treated effluents from wastewater treatment works can comprise a large proportion of the flow of rivers in the developed world. Exposure to these effluents, or the steroidal estrogens they contain, feminizes wild male fish and can reduce their reproductive fitness. Long-term experimental exposures have resulted in skewed sex ratios, reproductive failures in breeding colonies, and population collapse. This suggests that environmental estrogens could threaten the sustainability of wild fish populations. Results Here we tested this hypothesis by examining population genetic structures and effective population sizes (Ne) of wild roach (Rutilus rutilus L.) living in English rivers contaminated with estrogenic effluents. Ne was estimated from DNA microsatellite genotypes using approximate Bayesian computation and sibling assignment methods. We found no significant negative correlation between Ne and the predicted estrogen exposure at 28 sample sites. Furthermore, examination of the population genetic structure of roach in the region showed that some populations have been confined to stretches of river with a high proportion of estrogenic effluent for multiple generations and have survived, apparently without reliance on immigration of fish from less polluted sites. Conclusions These results demonstrate that roach populations living in some effluent-contaminated river stretches, where feminization is widespread, are self-sustaining. Although we found no evidence to suggest that exposure to estrogenic effluents is a significant driving factor in determining the size of roach breeding populations, a reduction in Ne of up to 65% is still possible for the most contaminated sites because of the wide confidence intervals associated with the statistical model. PMID:24417977

  2. Young adults' trajectories of Ecstasy use: a population based study.

    PubMed

    Smirnov, Andrew; Najman, Jake M; Hayatbakhsh, Reza; Plotnikova, Maria; Wells, Helene; Legosz, Margot; Kemp, Robert

    2013-11-01

    Young adults' Ecstasy use trajectories have important implications for individual and population-level consequences of Ecstasy use, but little relevant research has been conducted. This study prospectively examines Ecstasy trajectories in a population-based sample. Data are from the Natural History Study of Drug Use, a retrospective/prospective cohort study conducted in Australia. Population screening identified a probability sample of Ecstasy users aged 19-23 years. Complete data for 30 months of follow-up, comprising 4 time intervals, were available for 297 participants (88.4% of sample). Trajectories were derived using cluster analysis based on recent Ecstasy use at each interval. Trajectory predictors were examined using a generalized ordered logit model and included Ecstasy dependence (World Mental Health Composite International Diagnostic Instrument), psychological distress (Hospital Anxiety Depression Scale), aggression (Young Adult Self Report) and contextual factors (e.g. attendance at electronic/dance music events). Three Ecstasy trajectories were identified (low, intermediate and high use). At its peak, the high-use trajectory involved 1-2 days Ecstasy use per week. Decreasing frequency of use was observed for intermediate and high-use trajectories from 12 months, independently of market factors. Intermediate and high-use trajectory membership was predicted by past Ecstasy consumption (>70 pills) and attendance at electronic/dance music events. High-use trajectory members were unlikely to have used Ecstasy for more than 3 years and tended to report consistently positive subjective effects at baseline. Given the social context and temporal course of Ecstasy use, Ecstasy trajectories might be better understood in terms of instrumental rather than addictive drug use patterns.

  3. High population density enhances recruitment and survival of a harvested coral reef fish.

    PubMed

    Wormald, Clare L; Steele, Mark A; Forrester, Graham E

    2013-03-01

    A negative relationship between population growth and population density (direct density dependence) is necessary for population regulation and is assumed in most models of harvested populations. Experimental tests for density dependence are lacking for large-bodied, harvested fish because of the difficulty of manipulating population density over large areas. We studied a harvested coral reef fish, Lutjanus apodus (schoolmaster snapper), using eight large, isolated natural reefs (0.4-1.6 ha) in the Bahamas as replicates. An initial observational test for density dependence was followed by a manipulation of population density. The manipulation weakened an association between density and shelter-providing habitat features and revealed a positive effect of population density on recruitment and survival (inverse density dependence), but no effect of density on somatic growth. The snappers on an individual reef were organized into a few shoals, and we hypothesize that large shoals on high-density reefs were less vulnerable to large piscivores (groupers and barracudas) than the small shoals on low-density reefs. Reductions in predation risk for individuals in large social groups are well documented, but because snapper shoals occupied reefs the size of small marine reserves, these ecological interactions may influence the outcome of management actions.

  4. Connectivity, passability and heterogeneity interact to determine fish population persistence in river networks

    PubMed Central

    Samia, Yasmine; Lutscher, Frithjof; Hastings, Alan

    2015-01-01

    The movement of fish in watersheds is frequently inhibited by human-made migration barriers such as dams or culverts. The resulting lack of connectivity of spatial subpopulations is often cited as a cause for observed population decline. We formulate a matrix model for a spatially distributed fish population in a watershed, and we investigate how location and other characteristics of a single movement barrier impact the asymptotic growth rate of the population. We find that while population growth rate often decreases with the introduction of a movement obstacle, it may also increase due to a ‘retention effect’. Furthermore, obstacle mortality greatly affects population growth rate. In practice, different connectivity indices are used to predict population effects of migration barriers, but the relation of these indices to population growth rates in demographic models is often unclear. When comparing our results with the dentritic connectivity index, we see that the index captures neither the retention effect nor the influences of obstacle mortality. We argue that structural indices cannot entirely replace more detailed demographic models to understand questions of persistence and extinction. We advocate the development of novel functional indices and characteristics. PMID:26311313

  5. An observer for a nonlinear age-structured model of a harvested fish population.

    PubMed

    Ngom, Diène; Iggidr, Abderrahman; Guiro, Aboudramane; Ouahbi, Abderrahim

    2008-04-01

    We consider an age-structured model of a harvested population. This model is a discrete-time system that includes a nonlinear stock-recruitment relationship. Our purpose is to estimate the stock state. To achieve this goal, we built an observer, which is an auxiliary system that uses the total number of fish caught over each season and gives a dynamical estimation of the number of fish by age class. We analyse the convergence of the observer and we show that the error estimation tends to zero with exponential speed if a condition on the fishing effort is satisfied. Moreover the constructed observer (dynamical estimator) does not depend on the poorly understood stock-recruitment relationship. This study shows how some tools from nonlinear control theory can help to deal with the state estimation problem in the field of renewable resource management.

  6. Age and Time Population Differences: Young Adults, Gen Xers, and Millennials

    ERIC Educational Resources Information Center

    Menard, Lauren A.

    2013-01-01

    Age and Time disparities in young adult research populations are common because young adults are defined by varying age spans; members of Generation X and Millennial generations may both be considered young adults; study years vary, affecting populations; and qualitative methods with limited age/year samples are frequently utilized. The current…

  7. Adaptive divergence between lake and stream populations of an East African cichlid fish.

    PubMed

    Theis, Anya; Ronco, Fabrizia; Indermaur, Adrian; Salzburger, Walter; Egger, Bernd

    2014-11-01

    Divergent natural selection acting in different habitats may build up barriers to gene flow and initiate speciation. This speciation continuum can range from weak or no divergence to strong genetic differentiation between populations. Here, we focus on the early phases of adaptive divergence in the East African cichlid fish Astatotilapia burtoni, which occurs in both Lake Tanganyika (LT) and inflowing rivers. We first assessed the population structure and morphological differences in A. burtoni from southern LT. We then focused on four lake-stream systems and quantified body shape, ecologically relevant traits (gill raker and lower pharyngeal jaw) as well as stomach contents. Our study revealed the presence of several divergent lake-stream populations that rest at different stages of the speciation continuum, but show the same morphological and ecological trajectories along the lake-stream gradient. Lake fish have higher bodies, a more superior mouth position, longer gill rakers and more slender pharyngeal jaws, and they show a plant/algae and zooplankton-biased diet, whereas stream fish feed more on snails, insects and plant seeds. A test for reproductive isolation between closely related lake and stream populations did not detect population-assortative mating. Analyses of F1 offspring reared under common garden conditions indicate that the detected differences in body shape and gill raker length do not constitute pure plastic responses to different environmental conditions, but also have a genetic basis. Taken together, the A. burtoni lake-stream system constitutes a new model to study the factors that enhance and constrain progress towards speciation in cichlid fishes.

  8. Removal of nonnative fish results in population expansion of a declining amphibian (mountain yellow-legged frog, Rana muscosa)

    PubMed Central

    KNAPP, Roland A.; BOIANO, Daniel M.; VREDENBURG, Vance T.

    2007-01-01

    The mountain yellow-legged frog (Rana muscosa) was once a common inhabitant of the Sierra Nevada (California, USA), but has declined precipitously during the past century due in part to the introduction of nonnative fish into naturally fishless habitats. The objectives of the current study were to describe (1) the effect of fish removal from three lakes (located in two watersheds) on the small, remnant R. muscosa populations inhabiting those lakes, and (2) the initial development of metapopulation structure in each watershed as R. muscosa from expanding populations in fish-removal lakes dispersed to adjacent habitats. At all three fish-removal lakes, R. muscosa population densities increased significantly following the removal of predatory fish. The magnitude of these increases was significantly greater than that observed over the same time period in R. muscosa populations inhabiting control lakes that remained in their natural fishless condition. Following these population increases, R. muscosa dispersed to adjacent suitable (but unoccupied) sites, moving between 200 and 900 m along streams or across dry land. Together, these results suggest that large-scale removal of introduced fish could result in at least partial reversal of the decline of R. muscosa. Continued monitoring of R. muscosa at the fish-removal sites will be necessary to determine whether the positive effects of fish eradication are sustained over the long-term, especially in light of the increasingly important role played by an emerging infectious disease (chytridiomycosis, caused by Batrachochytrium dendrobatidis) in influencing R. muscosa populations. PMID:17396156

  9. Global warming may disproportionately affect larger adults in a predatory coral reef fish.

    PubMed

    Messmer, Vanessa; Pratchett, Morgan S; Hoey, Andrew S; Tobin, Andrew J; Coker, Darren J; Cooke, Steven J; Clark, Timothy D

    2016-11-03

    Global warming is expected to reduce body sizes of ectothermic animals. Although the underlying mechanisms of size reductions remain poorly understood, effects appear stronger at latitudinal extremes (poles and tropics) and in aquatic rather than terrestrial systems. To shed light on this phenomenon, we examined the size dependence of critical thermal maxima (CTmax) and aerobic metabolism in a commercially important tropical reef fish, the leopard coral grouper (Plectropomus leopardus) following acclimation to current-day (28.5 °C) vs. projected end-of-century (33 °C) summer temperatures for the northern Great Barrier Reef (GBR). CTmax declined from 38.3 to 37.5 °C with increasing body mass in adult fish (0.45-2.82 kg), indicating that larger individuals are more thermally sensitive than smaller conspecifics. This may be explained by a restricted capacity for large fish to increase mass-specific maximum metabolic rate (MMR) at 33 °C compared with 28.5 °C. Indeed, temperature influenced the relationship between metabolism and body mass (0.02-2.38 kg), whereby the scaling exponent for MMR increased from 0.74 ± 0.02 at 28.5 °C to 0.79 ± 0.01 at 33 °C, and the corresponding exponents for standard metabolic rate (SMR) were 0.75 ± 0.04 and 0.80 ± 0.03. The increase in metabolic scaling exponents at higher temperatures suggests that energy budgets may be disproportionately impacted in larger fish and contribute to reduced maximum adult size. Such climate-induced reductions in body size would have important ramifications for fisheries productivity, but are also likely to have knock-on effects for trophodynamics and functioning of ecosystems.

  10. Scale of Severe Channel Disturbances Relative to the Structure of Fish Populations

    NASA Astrophysics Data System (ADS)

    Luce, C. H.; Rieman, B. E.; King, J. G.; Dunham, J. B.

    2002-12-01

    Stream temperature and channel disturbance are two potentially important controls on the distribution and persistence of fish populations. Temperature regulates primary physiological processes that constrain the demographic response of populations to their environments. Ultimately temperature may be a first order determinant of the patterns of potential habitat and occurrence for many species. Stream temperature can be estimated from locally derived empirical relationships with elevation or based on detailed energy balances and thus used to model the distribution of potential habitats for fishes across whole landscapes. The role of disturbance is more hypothetical. Metapopulation theory proposes that environmental variation may have an important influence on the dynamics of populations. Disturbances may depress or even eliminate local populations, but a regional population may persist because other populations are not affected. Demographic support or recolonization may occur through dispersal among populations. Clearly the scale of disturbance and population structure can be important. If the characteristic size of disturbances is larger than the extent of a local population, then adjacent populations may decline simultaneously and metapopulation structure will offer little benefit. Conversely, if the characteristic size is smaller the benefit of structure could be important. In this paper we examine the spatial scale of large disturbances in the Boise River catchment over the last 50 years. We compare that to the scale of habitat patches for bull trout defined by stream temperature and the patterns of genetic variation detected by molecular techniques. Implications for species conservation are discussed in the context of climate change (influencing habitat patch size) and fire and fuels management (influencing the scale of disturbance).

  11. EFFECTS OF BENZO[A]PYRENE EXPOSURE ON A FISH POPULATION RESISTANT TO THE TOXIC EFFECTS OF DIOXIN-LIKE COMPOUNDS

    EPA Science Inventory

    Effects of a model polycyclic aromatic hydrocarbon (PAH) were compared in populations of the estuarine fish Fundulus heteroclitus indigenous to a reference site and one highly contaminated with polychlorinated biphenyls (PCBs) and other compounds. The fish population resident to ...

  12. A moving target--incorporating knowledge of the spatial ecology of fish into the assessment and management of freshwater fish populations.

    PubMed

    Cooke, Steven J; Martins, Eduardo G; Struthers, Daniel P; Gutowsky, Lee F G; Power, Michael; Doka, Susan E; Dettmers, John M; Crook, David A; Lucas, Martyn C; Holbrook, Christopher M; Krueger, Charles C

    2016-04-01

    Freshwater fish move vertically and horizontally through the aquatic landscape for a variety of reasons, such as to find and exploit patchy resources or to locate essential habitats (e.g., for spawning). Inherent challenges exist with the assessment of fish populations because they are moving targets. We submit that quantifying and describing the spatial ecology of fish and their habitat is an important component of freshwater fishery assessment and management. With a growing number of tools available for studying the spatial ecology of fishes (e.g., telemetry, population genetics, hydroacoustics, otolith microchemistry, stable isotope analysis), new knowledge can now be generated and incorporated into biological assessment and fishery management. For example, knowing when, where, and how to deploy assessment gears is essential to inform, refine, or calibrate assessment protocols. Such information is also useful for quantifying or avoiding bycatch of imperiled species. Knowledge of habitat connectivity and usage can identify critically important migration corridors and habitats and can be used to improve our understanding of variables that influence spatial structuring of fish populations. Similarly, demographic processes are partly driven by the behavior of fish and mediated by environmental drivers. Information on these processes is critical to the development and application of realistic population dynamics models. Collectively, biological assessment, when informed by knowledge of spatial ecology, can provide managers with the ability to understand how and when fish and their habitats may be exposed to different threats. Naturally, this knowledge helps to better evaluate or develop strategies to protect the long-term viability of fishery production. Failure to understand the spatial ecology of fishes and to incorporate spatiotemporal data can bias population assessments and forecasts and potentially lead to ineffective or counterproductive management actions.

  13. A moving target—incorporating knowledge of the spatial ecology of fish into the assessment and management of freshwater fish populations

    USGS Publications Warehouse

    Cooke, Steven J.; Martins, Eduardo G; Struthers, Daniel P; Gutowsky, Lee F G; Powers, Michael H.; Doka, Susan E; Dettmers, John M.; Crook, David A; Lucas, Martyn C.; Holbrook, Christopher; Krueger, Charles C.

    2016-01-01

    Freshwater fish move vertically and horizontally through the aquatic landscape for a variety of reasons, such as to find and exploit patchy resources or to locate essential habitats (e.g., for spawning). Inherent challenges exist with the assessment of fish populations because they are moving targets. We submit that quantifying and describing the spatial ecology of fish and their habitat is an important component of freshwater fishery assessment and management. With a growing number of tools available for studying the spatial ecology of fishes (e.g., telemetry, population genetics, hydroacoustics, otolith microchemistry, stable isotope analysis), new knowledge can now be generated and incorporated into biological assessment and fishery management. For example, knowing when, where, and how to deploy assessment gears is essential to inform, refine, or calibrate assessment protocols. Such information is also useful for quantifying or avoiding bycatch of imperiled species. Knowledge of habitat connectivity and usage can identify critically important migration corridors and habitats and can be used to improve our understanding of variables that influence spatial structuring of fish populations. Similarly, demographic processes are partly driven by the behavior of fish and mediated by environmental drivers. Information on these processes is critical to the development and application of realistic population dynamics models. Collectively, biological assessment, when informed by knowledge of spatial ecology, can provide managers with the ability to understand how and when fish and their habitats may be exposed to different threats. Naturally, this knowledge helps to better evaluate or develop strategies to protect the long-term viability of fishery production. Failure to understand the spatial ecology of fishes and to incorporate spatiotemporal data can bias population assessments and forecasts and potentially lead to ineffective or counterproductive management actions.

  14. Life and health satisfaction in the adult population of Iran

    PubMed Central

    2016-01-01

    OBJECTIVES Increasing interest has emerged in the use of subjective well-being as a development indicator and for the evaluation of public policies. The aim of this study was to assess life and health satisfaction and their determinants in the adult population of Iran. METHODS We conducted a survey of a sample of 3,150 adults at least 18 years of age in Tehran, the capital of Iran. The subjects were selected using a stratified random sampling method, and they were interviewed face-to-face at their usual residence by trained interviewers. Life satisfaction was used as a measure of subjective well-being. We used ordinary least square regression models to assess the associations of life and health satisfaction with socio-demographic variables. RESULTS On a 0-10 scale, the mean (standard deviation) scores for life and health satisfaction were 6.93 (2.54) and 7.18 (1.97), respectively. The average score for life satisfaction in females was 0.52 points higher than in males. A U-shaped relationship was found between age and life satisfaction, with respondents 35 to 44 years of age having the lowest average level of life satisfaction. Satisfaction with life and health among divorced respondents was significantly lower than among never-married and married participants. The scores for life satisfaction in respondents who rated their health status as poor were 3.83 points lower than in those who rated their health status as excellent. CONCLUSIONS The majority of the population of Tehran was satisfied with their life and health. Self-rated health status had the greatest impact on life satisfaction. PMID:27809456

  15. Communicating methylmercury risks and fish consumption benefits to vulnerable childbearing populations.

    PubMed

    Kuntz, Sandra W; Ricco, Jason A; Hill, Wade G; Anderko, Laura

    2010-01-01

    Methylmercury is a known neurotoxin especially harmful to the fetus, infant, and child. Preventing exposure to this environmental toxin is best accomplished through consumer messages specifically adapted for local populations. Health care providers play an important role in the dissemination of information. The purpose of this article is to review the benefits and risks of fish consumption and identify strategies for presenting effective risk communication messages to vulnerable groups, particularly women of childbearing age.

  16. Electrocommunication signals alone are sufficient to increase neurogenesis in the brain of adult electric fish, Apteronotus leptorhynchus.

    PubMed

    Dunlap, Kent D; McCarthy, Elizabeth A; Jashari, Denisa

    2008-10-01

    Social interaction can have profound influences on the structure of the adult brain, but little is known about the precise stimulus feature found within social interaction that induces such brain plasticity. We examined the effects of social stimuli on cell addition and radial glial fiber formation in the brains of adult electric fish. These fish communicate primarily through weak, quasi-sinusoidal electric signals. Fish were housed in isolation, paired with another fish or exposed to only the electrocommunication signals of another fish for 7 days. After 3 days of exposure to these stimulus conditions, fish were injected with bromodeoxyuridine (BrdU) to mark newborn cells. We sacrificed the fish 4 days after BrdU injection and used immunohistochemistry to measure cell addition (BrdU+), the fraction of added cells that differentiated into neurons (BrdU+/NeuroTrace+) and the density of radial glia fibers (vimentin+) in the periventricular zone of the diencephalon. Fish that were exposed only to the electrocommunication signals of another fish and no other social stimuli had equivalent levels of cell addition and radial glial fiber density to fish that were housed with full social interaction and higher levels than fish housed in isolation. About 60% of the added cells differentiated into neurons; this fraction did not differ among treatment groups. Artificial sine wave electrical stimuli that mimicked electrocommunication signals were ineffective in increasing cell addition and glia fiber formation above those found in isolated fish. Thus, stimuli through a single modality are sufficient for inducing this brain plasticity, but the waveform or dynamic features of communication signals are crucial for the effect.

  17. Does exposure to domestic wastewater effluent (including steroid estrogens) harm fish populations in the UK?

    PubMed

    Johnson, Andrew C; Chen, Yihong

    2017-07-01

    Historic fisheries data collected from locations across the UK over several years were compared with predicted estrogen exposure derived from the resident human population. This estrogen exposure could be viewed as a proxy for general sewage (wastewater) exposure. With the assistance of the Environment Agency in the UK, fisheries abundance data for Rutilis rutilis (roach), Alburnus alburnus (bleak), Leuciscus leuciscus (dace) and Perca fluviatilis (perch) from 38 separate sites collected over 7 to 17year periods were retrieved. From these data the average density (fish/m(2)/year) were compared against average and peak predicted estrogen (wastewater) exposure for these sites. Estrogen concentrations were predicted using the LF2000-WQX model. No correlation between estrogen/wastewater exposure and fish density could be found for any of the species. Year on year temporal changes in roach population abundance at 3 sites on the middle River Thames and 4 sites on the Great Ouse were compared against estrogen exposure over the preceding year. In this case the estrogen prediction was calculated based on the upstream human population providing the estrogen load and the daily flow value allowing concentration to be estimated over time. At none of the sites on these rivers were temporal declines in abundance associated with preceding estrogen (effluent) exposure. The results indicate that, over the past decade, wastewater and estrogen exposure has not led to a catastrophic decline in these four species of cyprinid fish.

  18. Population expansions dominate demographic histories of endemic and widespread Pacific reef fishes

    PubMed Central

    Delrieu-Trottin, Erwan; Mona, Stefano; Maynard, Jeffrey; Neglia, Valentina; Veuille, Michel; Planes, Serge

    2017-01-01

    Despite the unique nature of endemic species, their origin and population history remain poorly studied. We investigated the population history of 28 coral reef fish species, close related, from the Gambier and Marquesas Islands, from five families, with range size varying from widespread to small-range endemic. We analyzed both mitochondrial and nuclear sequence data using neutrality test and Bayesian analysis (EBSP and ABC). We found evidence for demographic expansions for most species (24 of 28), irrespective of range size, reproduction strategy or archipelago. The timing of the expansions varied greatly among species, from 8,000 to 2,000,000 years ago. The typical hypothesis for reef fish that links population expansions to the Last Glacial Maximum fit for 14 of the 24 demographic expansions. We propose two evolutionary processes that could lead to expansions older than the LGM: (a) we are retrieving the signature of an old colonization process for widespread, large-range endemic and paleoendemic species or (b) speciation; the expansion reflects the birth of the species for neoendemic species. We show for the first time that the demographic histories of endemic and widespread reef fish are not distinctly different and suggest that a number of processes drive endemism. PMID:28091580

  19. Population expansions dominate demographic histories of endemic and widespread Pacific reef fishes.

    PubMed

    Delrieu-Trottin, Erwan; Mona, Stefano; Maynard, Jeffrey; Neglia, Valentina; Veuille, Michel; Planes, Serge

    2017-01-16

    Despite the unique nature of endemic species, their origin and population history remain poorly studied. We investigated the population history of 28 coral reef fish species, close related, from the Gambier and Marquesas Islands, from five families, with range size varying from widespread to small-range endemic. We analyzed both mitochondrial and nuclear sequence data using neutrality test and Bayesian analysis (EBSP and ABC). We found evidence for demographic expansions for most species (24 of 28), irrespective of range size, reproduction strategy or archipelago. The timing of the expansions varied greatly among species, from 8,000 to 2,000,000 years ago. The typical hypothesis for reef fish that links population expansions to the Last Glacial Maximum fit for 14 of the 24 demographic expansions. We propose two evolutionary processes that could lead to expansions older than the LGM: (a) we are retrieving the signature of an old colonization process for widespread, large-range endemic and paleoendemic species or (b) speciation; the expansion reflects the birth of the species for neoendemic species. We show for the first time that the demographic histories of endemic and widespread reef fish are not distinctly different and suggest that a number of processes drive endemism.

  20. Population expansions dominate demographic histories of endemic and widespread Pacific reef fishes

    NASA Astrophysics Data System (ADS)

    Delrieu-Trottin, Erwan; Mona, Stefano; Maynard, Jeffrey; Neglia, Valentina; Veuille, Michel; Planes, Serge

    2017-01-01

    Despite the unique nature of endemic species, their origin and population history remain poorly studied. We investigated the population history of 28 coral reef fish species, close related, from the Gambier and Marquesas Islands, from five families, with range size varying from widespread to small-range endemic. We analyzed both mitochondrial and nuclear sequence data using neutrality test and Bayesian analysis (EBSP and ABC). We found evidence for demographic expansions for most species (24 of 28), irrespective of range size, reproduction strategy or archipelago. The timing of the expansions varied greatly among species, from 8,000 to 2,000,000 years ago. The typical hypothesis for reef fish that links population expansions to the Last Glacial Maximum fit for 14 of the 24 demographic expansions. We propose two evolutionary processes that could lead to expansions older than the LGM: (a) we are retrieving the signature of an old colonization process for widespread, large-range endemic and paleoendemic species or (b) speciation; the expansion reflects the birth of the species for neoendemic species. We show for the first time that the demographic histories of endemic and widespread reef fish are not distinctly different and suggest that a number of processes drive endemism.

  1. Plate-like permanent dental laminae of upper jaw dentition in adult gobiid fish, Sicyopterus japonicus.

    PubMed

    Moriyama, Keita; Watanabe, Shun; Iida, Midori; Sahara, Noriyuki

    2010-04-01

    Sicyopterus japonicus (Teleostei, Gobiidae) possesses a unique upper jaw dentition different from that known for any other teleosts. In the adults, many (up to 30) replacement teeth, from initiation to attachment, are arranged orderly in a semicircular-like strand within a capsule of connective tissue on the labial side of each premaxillary bone. We have applied histological, ultrastructural, and three-dimensional imaging from serial sections to obtain insights into the distribution and morphological features of the dental lamina in the upper jaw dentition of adult S. japonicus. The adult fish has numerous permanent dental laminae, each of which is an infolding of the oral epithelium at the labial side of the functional tooth and forms a thin plate-like structure with a wavy contour. All replacement teeth of a semicircular-like strand are connected to the plate-like dental lamina by the outer dental epithelium and form a tooth family; neighboring tooth families are completely separated from each other. The new tooth germ directly buds off from the ventro-labial margin of the dental lamina, whereas no distinct free end of the dental lamina is present, even adjacent to this region. Cell proliferation concentrated at the ventro-labial margin of the dental lamina suggests that this region is the site for repeated tooth initiation. During tooth development, the replacement tooth migrates along a semicircular-like strand and eventually erupts through the dental lamina into the oral epithelium at the labial side of the functional tooth. This unique thin plate-like permanent dental lamina and the semicircular-like strand of replacement teeth in the upper jaw dentition of adult S. japonicus probably evolved as a dental adaptation related to the rapid replacement of teeth dictated by the specialized feeding habit of this algae-scraping fish.

  2. Population dynamics of wetland fishes: Spatio-temporal patterns synchronized by hydrological disturbance?

    USGS Publications Warehouse

    Ruetz, C. R.; Trexler, J.C.; Jordan, F.; Loftus, W.F.; Perry, S.A.

    2005-01-01

    1. Drought is a natural disturbance that can cause widespread mortality of aquatic organisms in wetlands. We hypothesized that seasonal drying of marsh surfaces (i.e. hydrological disturbance) shapes spatio-temporal patterns of fish populations. 2. We tested whether population dynamics of fishes were synchronized by hydrological disturbance (Moran effect) or distance separating study sites (dispersal). Spatio-temporal patterns were examined in local populations of five abundant species at 17 sites (sampled five times per year from 1996 to 2001) in a large oligotrophic wetland. 3. Fish densities differed significantly across spatio-temporal scales for all species. For all species except eastern mosquitofish (Gambusia holbrooki), a significant portion of spatio-temporal variation in density was attributed to drying events (used as a covariate). 4. We observed three patterns of response to hydrological disturbance. Densities of bluefin killifish (Lucania goodei), least killifish (Heterandria formosa), and golden top-minnow (Fundulus chrysotus) were usually lowest after a dry down and recovered slowly. Eastern mosquitofish showed no distinct response to marsh drying (i.e. they recovered quickly). Flagfish (Jordanella floridae) density was often highest after a dry down and then declined. Population growth after a dry down was often asymptotic for bluefin killifish and golden topminnow, with greatest asymptotic density and longest time to recovery at sites that dried infrequently. 5. Fish population dynamics were synchronized by hydrological disturbance (independent of distance) and distance separating study sites (independent of hydrological disturbance). Our ability to separate the relative importance of the Moran effect from dispersal was strengthened by a weak association between hydrological synchrony and distance among study sites. Dispersal was the primary mechanism for synchronous population dynamics of flagfish, whereas hydrological disturbance was the primary

  3. A randomised study on the effects of fish protein supplement on glucose tolerance, lipids and body composition in overweight adults.

    PubMed

    Vikøren, Linn A; Nygård, Ottar K; Lied, Einar; Rostrup, Espen; Gudbrandsen, Oddrun A

    2013-02-28

    The popularity of high-protein diets for weight reduction is immense. However, the potential benefits from altering the source of dietary protein rather than the amount is scarcely investigated. In the present study, we examined the effects of fish protein supplement on glucose and lipid metabolism in overweight adults. A total of thirty-four overweight adults were randomised to 8 weeks' supplementation with fish protein or placebo tablets (controls). The intake of fish protein supplement was 3 g/d for the first 4 weeks and 6 g/d for the last 4 weeks. In this study, 8 weeks of fish protein supplementation resulted in lower values of fasting glucose (P< 0·05), 2 h postprandial glucose (P< 0·05) and glucose-area under the curve (AUC) (five measurements over 2 h, P< 0·05) after fish protein supplementation compared to controls. Glucose-AUC was decreased after 8 weeks with fish protein supplement compared to baseline (P< 0·05), concomitant with increased 30 min and decreased 90 min and 2 h insulin C-peptide level (P< 0·05), and reduced LDL-cholesterol (P< 0·05). Body muscle % was increased (P< 0·05) and body fat % was reduced (P< 0·05) after 4 weeks' supplementation. Physical activity and energy and macronutrients intake did not change during the course of the study. In conclusion, short-term daily supplementation with a low dose of fish protein may have beneficial effects on blood levels of glucose and LDL-cholesterol as well as glucose tolerance and body composition in overweight adults. The long-term effects of fish protein supplementation is of interest in the context of using more fish as a protein source in the diet, and the effects of inclusion of fish in the diet of individuals with low glucose tolerance should be evaluated.

  4. Successional change in the Lake Superior fish community: population trends in ciscoes, rainbow smelt, and lake trout, 1958-2008

    USGS Publications Warehouse

    Gorman, Owen T.

    2012-01-01

    The Lake Superior fish community underwent massive changes in the second half of the 20th century. Those changes are largely reflected in changes in abundance of the adults of principal prey species, the ciscoes (Coregonus spp.), the invasive rainbow smelt (Osmerus mordax), and the principal predator, lake trout (Salvelinus namaycush). To better understand changes in species abundances, a comprehensive series of gillnet and bottom trawl data collected from 1958 to 2008 were examined. In the late 1950s/early 1960s, smelt abundance was at its maximum, wild lake trout was at its minimum, and an abundance of hatchery lake trout was increasing rapidly. The bloater (Coregonus hoyi) was the prevalent cisco in the lake; abundance was more than 300% greater than the next most abundant cisco, shortjaw cisco (C. zenithicus), followed by kiyi (C. kiyi) and lake cisco (C. artedi). By the mid-1960s, abundance of hatchery lake trout was nearing maximum, smelt abundance was beginning to decline, and abundances of all ciscoes declined, but especially that of shortjaw cisco and kiyi. By the late 1970s, recovery of wild lake trout stocks was well underway and abundances of hatchery lake trout and smelt were declining and the ciscoes were reaching their nadir. During 1980–1990, the fish community underwent a dramatic shift in organization and structure. The rapid increase in abundance of wild lake trout, concurrent with a rapid decline in hatchery lake trout, signaled the impending recovery. Rainbow smelt abundance dropped precipitously and within four years, lake cisco and bloater populations rebounded on the heels of a series of strong recruitment events. Kiyi populations showed signs of recovery by 1989, and shortjaw by 2000, though well below historic maximum abundances. High abundance of adult smelt prior to 1980 appears to be the only factor linked to recruitment failure in the ciscoes. Life history traits of the cisco species were examined to better understand their different

  5. Prevalence of Dental Caries in Kosovar Adult Population

    PubMed Central

    Begzati, Agim; Kelmendi, Jeta; Ilijazi, Donika; Kqiku, Lumnije

    2016-01-01

    Objectives. The aim of this study was to assess the prevalence of dental caries in the Kosovar adult population. Materials and Methods. A cross-sectional study in Kosovo was conducted examining 9387 patients, aged 18 upwards, between January 2010 and December 2011. Clinical evaluation was done using WHO criteria for evaluation of dental health status and data collection. Results. The prevalence of caries for the whole study was 72.80%. The mean DMFT index was 9.61 (±5.12) in the 18–34-year age group, 11.6 (±6.42) in the 35–44-year age group, 13.68 (±8.12) among the 45–64-year age group, 17.98 (±9.81) in the 65–74-year age group, and 23.19 (±9.41) in the age group of 75+ years, respectively. A significant difference of mean DMFT and its each component was observed between the ages (P < 0.001). Conclusion. This study comes out with the significant levels of dental caries among young Kosovar population (18–34 years old). PMID:27516774

  6. Airway responsiveness to sulfur dioxide in an adult population sample.

    PubMed

    Nowak, D; Jörres, R; Berger, J; Claussen, M; Magnussen, H

    1997-10-01

    We determined the prevalence of airway hyperresponsiveness to sulfur dioxide (SO2) in an adult population sample of 790 subjects 20 to 44 yr of age. Subjects were drawn randomly from the population of Hamburg, Northern Germany, within the framework of the European Community Respiratory Health Survey. In addition, we analyzed the relationship between SO2 responsiveness and a number of risk factors, such as a history of respiratory symptoms, methacholine responsiveness, and atopy derived from skin-prick test results. SO2 inhalation challenges were performed during isocapnic hyperventilation at constant rate (40 L x min(-1), for 3 min) with doubling concentrations of SO2 up to a maximum concentration of 2.0 ppm. If subjects achieved a 20% decrease in FEV1 from baseline during the challenge, they were considered to be hyperresponsive to SO2. The raw prevalence of SO2 hyperresponsiveness within the population sample studied was 3.4% (95% confidence interval [CI]: 2.3 to 5.0%). Adjustment for nonparticipation led to an estimated prevalence of SO2 hyperresponsiveness of 5.4%. Among subjects with hyperresponsiveness to methacholine, 22.4% (95% CI: 20.1 to 25.3) demonstrated hyperresponsiveness to SO2. There was no significant correlation between the degrees of hyperresponsiveness to methacholine and SO2. Predictors of a positive SO2 response were hyperresponsiveness to methacholine (p < 0.0001), a positive history of respiratory symptoms (p < 0.05), and a positive skin-prick test to at least one common allergen (p < 0.05). We conclude from these data that airway hyperresponsiveness to SO2 can be found in about 20 to 25% of subjects within the 20- to 44-yr age range who are hyperresponsive to methacholine.

  7. Morphometric analysis of Mauthner axon cytoskeletal components in adult and subadult fish.

    PubMed

    Alfei, L; Medolago-Albani, L; Zezze, G M; Stefanelli, A

    1992-01-01

    A previous cytoskeletal analysis on trout MA during developmental stages demonstrated, during the subadult stages, neurofilaments (NF) as main components as expressed by the high values of neurofilament to microtubules (MT) ratio which was found to be of the order of 300:1. Since the MA cytoskeletal composition is not known in the adult fish, the MA cytoskeletal composition has been compared to other axons of much smaller diameter of the fasciculus longitudinalis medialis (flm) among which the MA run in the ventral spinal cord. The following parameters were measured on conventional electron microscopy in MA and flm axons cross sections micrographs by means of a computer linked graphic tablet (Apple II): axonal caliber, number of microtubules (MT), microtubular (MT/microns2) and neurofilament (NF/microns2) densities. The analysis of these parameters demonstrated that neurofilaments are the main architectural components in the adult and subadult fish MA and flm axons. However, MA cytoskeletal composition differs from the other flm axons because of its particular very high ratio of neurofilaments to microtubules. The inverse relationship of axonal caliber to microtubular density, previously found in the trout during developmental stages and suggested also for many other vertebrate species, was further confirmed for flm axons which, with calibers 10 times smaller than MA, exhibit a microtubular density 10 times larger.

  8. Contrasting Genetic Structure among Populations of Two Amphidromous Fish Species (Sicydiinae) in the Central West Pacific

    PubMed Central

    Taillebois, Laura; Castelin, Magalie; Ovenden, Jennifer R.; Bonillo, Céline; Keith, Philippe

    2013-01-01

    Both present-day and past processes can shape connectivity of populations. Pleistocene vicariant events and dispersal have shaped the present distribution and connectivity patterns of aquatic species in the Indo-Pacific region. In particular, the processes that have shaped distribution of amphidromous goby species still remain unknown. Previous studies show that phylogeographic breaks are observed between populations in the Indian and Pacific Oceans where the shallow Sunda shelf constituted a geographical barrier to dispersal, or that the large spans of open ocean that isolate the Hawaiian or Polynesian Islands are also barriers for amphidromous species even though they have great dispersal capacity. Here we assess past and present genetic structure of populations of two amphidromous fish (gobies of the Sicydiinae) that are widely distributed in the Central West Pacific and which have similar pelagic larval durations. We analysed sections of mitochondrial COI, Cytb and nuclear Rhodospine genes in individuals sampled from different locations across their entire known range. Similar to other Sicydiinae fish, intraspecific mtDNA genetic diversity was high for all species (haplotype diversity between 0.9–0.96). Spatial analyses of genetic variation in Sicyopus zosterophorum demonstrated strong isolation across the Torres Strait, which was a geologically intermittent land barrier linking Australia to Papua New Guinea. There was a clear genetic break between the northwestern and the southwestern clusters in Si. zosterophorum (φST = 0.67502 for COI) and coalescent analyses revealed that the two populations split at 306 Kyr BP (95% HPD 79–625 Kyr BP), which is consistent with a Pleistocene separation caused by the Torres Strait barrier. However, this geographical barrier did not seem to affect Sm. fehlmanni. Historical and demographic hypotheses are raised to explain the different patterns of population structure and distribution between these species. Strategies

  9. Genetic diversity affects the strength of population regulation in a marine fish.

    PubMed

    Johnson, D W; Freiwald, J; Bernardi, G

    2016-03-01

    Variation is an essential feature of biological populations, yet much of ecological theory treats individuals as though they are identical. This simplifying assumption is often justified by the perception that variation among individuals does not have significant effects on the dynamics of whole populations. However, this perception may be skewed by a historic focus on studying single populations. A true evaluation of the extent to which among-individual variation affects the dynamics of populations requires the study of multiple populations. In this study, we examined variation in the dynamics of populations of a live-bearing, marine fish (black surfperch; Embiotoca jacksoni). In collaboration with an organization of citizen scientists (Reef Check California), we were able to examine the dynamics of eight populations that were distributed throughout approximately 700 km of coastline, a distance that encompasses much of this species' range. We hypothesized that genetic variation within a local population would be related to the intensity of competition and to the strength of population regulation. To test this hypothesis, we examined whether genetic diversity (measured by the diversity of mitochondrial DNA haplotypes) was related to the strength of population regulation. Low-diversity populations experienced strong density dependence in population growth rates and population sizes were regulated much more tightly than they were in high-diversity populations. Mechanisms that contributed to this pattern include links between genetic diversity, habitat use, and spatial crowding. On average, low-diversity populations used less of the available habitat and exhibited greater spatial clustering (and more intense competition) for a given level of density (measured at the scale of the reef). Although the populations we studied also varied with respect to exogenous characteristics (habitat complexity, densities of predators, and interspecific competitors), none of these

  10. p53 Mutation suppresses adult neurogenesis in medaka fish (Oryzias latipes)

    SciTech Connect

    Isoe, Yasuko; Okuyama, Teruhiro; Taniguchi, Yoshihito; Kubo, Takeo; Takeuchi, Hideaki

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer Progenitor migration is accompanied by an increase in their numbers in the adult brain. Black-Right-Pointing-Pointer p53 Mutation suppressed an increase in the number of the migrated progenitors. Black-Right-Pointing-Pointer The decreased progenitor number is not due to enhanced cell death. Black-Right-Pointing-Pointer p53 Mutation did not affect proliferation of stem cells. -- Abstract: Tumor suppressor p53 negatively regulates self-renewal of neural stem cells in the adult murine brain. Here, we report that the p53 null mutation in medaka fish (Oryzias latipes) suppressed neurogenesis in the telencephalon, independent of cell death. By using 5-bromo-29-deoxyuridine (BrdU) immunohistochemistry, we identified 18 proliferation zones in the brains of young medaka fish; in situ hybridization showed that p53 was expressed selectively in at least 12 proliferation zones. We also compared the number of BrdU-positive cells present in the whole telencephalon of wild-type (WT) and p53 mutant fish. Immediately after BrdU exposure, the number of BrdU-positive cells did not differ significantly between them. One week after BrdU-exposure, the BrdU-positive cells migrated from the proliferation zone, which was accompanied by an increased number in the WT brain. In contrast, no significant increase was observed in the p53 mutant brain. Terminal deoxynucleotidyl transferase (dUTP) nick end-labeling revealed that there was no significant difference in the number of apoptotic cells in the telencephalon of p53 mutant and WT medaka, suggesting that the decreased number of BrdU-positive cells in the mutant may be due to the suppression of proliferation rather than the enhancement of neural cell death. These results suggest that p53 positively regulates neurogenesis via cell proliferation.

  11. Framework for Evaluating Habitat Restoration Success with Respect to Fish Habitat- and Population-related Beneficial Use Impairments

    EPA Science Inventory

    A major challenge of evaluating restoration progress is establishing a cause-effect relationship between observed changes in fish abundance and ongoing aquatic habitat restoration. Since 1979, fish populations within the St. Louis River Area of Concern, which were severely degrad...

  12. The use of tumors in wild populations of fish to assess ecosystem health

    USGS Publications Warehouse

    Baumann, Paul C.

    1992-01-01

    Evidence has linked toxicants in aquatic systems with cancer in fish and population level effects on species. Thus some types of tumors may be useful monitors of ecosystem health, at least as affected by genotoxins and promoters. However, tumors caused by purely genetic mechanisms or by virus would not be good indicators. Only neoplasms which have chemicals as a portion of their etiology (either as initiators or promoters) would be useful in assessing ecosystem health. Lesions which may fit these criteria include liver neoplasms (both biliary and hepatic) and skin lesions in a variety of primarily benthic fishes, and neural lesions in various drum species and in butterfly fish species. Two studies purporting to demonstrate a lack of tumors in fish from polluted areas have been reexamined and found either to have insufficient data on vulnerable species or to actually support a tumor-pollution linkage. Thus certain lesions in vulnerable species or species groups may serve as a mechanism to assess one facet of ecosystem health.

  13. Expansion of Dreissena into offshore waters of Lake Michigan and potential impacts on fish populations

    USGS Publications Warehouse

    Bunnell, D.B.; Madenjian, C.P.; Holuszko, J.D.; Adams, J.V.; French, J. R. P.

    2009-01-01

    Lake Michigan was invaded by zebra mussels (Dreissena polymorpha) in the late 1980s and then followed by quagga mussels (D. bugensis) around 1997. Through 2000, both species (herein Dreissena) were largely restricted to depths less than 50??m. Herein, we provide results of an annual lake-wide bottom trawl survey in Lake Michigan that reveal the relative biomass and depth distribution of Dreissena between 1999 and 2007 (although biomass estimates from a bottom trawl are biased low). Lake-wide mean biomass density (g/m2) and mean depth of collection revealed no trend between 1999 and 2003 (mean = 0.7??g/m2 and 37??m, respectively). Between 2004 and 2007, however, mean lake-wide biomass density increased from 0.8??g/m2 to 7.0??g/m2, because of increased density at depths between 30 and 110??m, and mean depth of collection increased from 42 to 77??m. This pattern was confirmed by a generalized additive model. Coincident with the Dreissena expansion that occurred beginning in 2004, fish biomass density (generally planktivores) declined 71% between 2003 and 2007. Current understanding of fish population dynamics, however, indicates that Dreissena expansion is not the primary explanation for the decline of fish, and we provide a species-specific account for more likely underlying factors. Nonetheless, future sampling and research may reveal a better understanding of the potential negative interactions between Dreissena and fish in Lake Michigan and elsewhere.

  14. The power to detect trends in Missouri River fish populations within the Pallid Sturgeon Population Assessment Program

    USGS Publications Warehouse

    Bryan, Janice L.; Wildhaber, Mark L.; Gladish, Dan; Holan, Scott; Ellerseick, Mark

    2010-01-01

    As with all large rivers in the United States, the Missouri River has been altered, with approximately 32.5 percent of the main stem length impounded and 32.5 percent channelized. These physical alterations to the environment have had effects on the fisheries, but studies examining the effects of alterations have been localized and for short periods of time. In response to the U.S. Fish and Wildlife Service biological opinion, the U.S. Army Corps of Engineers initiated monitoring of the fish community of the Missouri River in 2003. The goal of the Pallid Sturgeon Population Assessment Program is to provide information to detect changes in populations and habitat preferences with time for pallid sturgeon (Scaphirhynchus albus) and native target species in the Missouri River Basin. To determine statistical power of the Pallid Sturgeon Population Assessment Program, a power analysis was conducted using a normal linear mixed model with variance component estimates based on the first 3 years of data (2003 to 2005). In cases where 3 years of data were unavailable, estimates were obtained using those data. It was determined that at least 20 years of data, sampling 12 bends with 8 subsamples per bend, would be required to detect a 5 percent annual decline in most of the target fish populations. Power varied between Zones. Zone 1 (upstream from Lake Sakakawea) did not have any species/gear type combinations with adequate power, whereas Zone 3 (downstream from Gavins Point Dam) had 19 species/gear type combinations with adequate power. With a slight increase in the sampling effort to 12 subsamples per bend, the Pallid Sturgeon Population Assessment Program has adequate power to detect declines in shovelnose sturgeon (S. platorynchus) throughout the entire Missouri River because of large catch rates. The lowest level of non-occurrence (in other words, zero catches) at the bend level for pallid sturgeon was 0.58 using otter trawls in Zone 1. Consequently, the power of the

  15. Comparing Climate Change and Species Invasions as Drivers of Coldwater Fish Population Extirpations

    PubMed Central

    Sharma, Sapna; Vander Zanden, M. Jake; Magnuson, John J.; Lyons, John

    2011-01-01

    Species are influenced by multiple environmental stressors acting simultaneously. Our objective was to compare the expected effects of climate change and invasion of non-indigenous rainbow smelt (Osmerus mordax) on cisco (Coregonus artedii) population extirpations at a regional level. We assembled a database of over 13,000 lakes in Wisconsin, USA, summarising fish occurrence, lake morphology, water chemistry, and climate. We used A1, A2, and B1 scenarios from the Intergovernmental Panel on Climate Change (IPCC) of future temperature conditions for 15 general circulation models in 2046–2065 and 2081–2100 totalling 78 projections. Logistic regression indicated that cisco tended to occur in cooler, larger, and deeper lakes. Depending upon the amount of warming, 25–70% of cisco populations are predicted to be extirpated by 2100. In addition, cisco are influenced by the invasion of rainbow smelt, which prey on young cisco. Projecting current estimates of rainbow smelt spread and impact into the future will result in the extirpation of about 1% of cisco populations by 2100 in Wisconsin. Overall, the effect of climate change is expected to overshadow that of species invasion as a driver of coldwater fish population extirpations. Our results highlight the potentially dominant role of climate change as a driver of biotic change. PMID:21860661

  16. Comparing climate change and species invasions as drivers of coldwater fish population extirpations.

    PubMed

    Sharma, Sapna; Vander Zanden, M Jake; Magnuson, John J; Lyons, John

    2011-01-01

    Species are influenced by multiple environmental stressors acting simultaneously. Our objective was to compare the expected effects of climate change and invasion of non-indigenous rainbow smelt (Osmerus mordax) on cisco (Coregonus artedii) population extirpations at a regional level. We assembled a database of over 13,000 lakes in Wisconsin, USA, summarising fish occurrence, lake morphology, water chemistry, and climate. We used A1, A2, and B1 scenarios from the Intergovernmental Panel on Climate Change (IPCC) of future temperature conditions for 15 general circulation models in 2046-2065 and 2081-2100 totalling 78 projections. Logistic regression indicated that cisco tended to occur in cooler, larger, and deeper lakes. Depending upon the amount of warming, 25-70% of cisco populations are predicted to be extirpated by 2100. In addition, cisco are influenced by the invasion of rainbow smelt, which prey on young cisco. Projecting current estimates of rainbow smelt spread and impact into the future will result in the extirpation of about 1% of cisco populations by 2100 in Wisconsin. Overall, the effect of climate change is expected to overshadow that of species invasion as a driver of coldwater fish population extirpations. Our results highlight the potentially dominant role of climate change as a driver of biotic change.

  17. Microgeographic population structure of green swordail fish: genetic differentiation despite abundant migration.

    PubMed

    Tatarenkov, A; Healey, C I M; Avise, J C

    2010-01-01

    Swordtails (Xiphophorus; Poeciliidae) have figured prominently in research on fish mating behaviours, sexual selection, and carcinogenesis, but their population structures and dispersal patterns have been relatively neglected. Using nine microsatellite loci, we estimated genetic differentiation in Xiphophorus helleri within and between adjacent streams in Belize. The genetic data were complemented by a tagging study of movement within one stream. In the absence of physical dispersal barriers (waterfalls), population structure followed an isolation by distance (IBD) pattern. Genetic differentiation (F(ST) up to 0.07) was significant between and within creeks, despite high dispersal in the latter as judged by the tagging data. Such heterogeneity apparently was a result of genetic drift in local demes, due to small population sizes and highly skewed paternity. The IBD pattern was interrupted by waterfalls, boosting F(ST) above 0.30 between adjacent samples across these barriers. Overall, our results are helpful in understanding the interplay of evolutionary forces and population dynamics in a small fish living in a changeable habitat.

  18. POPULATION GENETIC STRUCTURE OF A NON-MIGRATORY MARINE FISH FUNDULUS HETERCLITUS ACROSS A STRONG GRADIENT OF PCB CONTAMINATION

    EPA Science Inventory

    Populations of the estuarine fish Fundulus heteroclitus indigenous to contaminated sites exhibit heritable resistance to some of the toxic effects of early life-stage exposure to polychlorinated biphenyls (PCBs). This evolved tolerance provides evidence of strong selection by PCB...

  19. Mycobacteria in adult salmonid fishes returning to national fish hatcheries in Washington, Oregon and California in 1958-59

    USGS Publications Warehouse

    Ross, A.J.

    1963-01-01

    Incidence of acid-fast bacillus infections in salmonid fishes at West Coast hatcheries was determined for 1957-59. No evidence was obtained which would indicate a definite trend towards either increased or decreased rates of infection. It is apparent that the incidence of infection is higher in hatchery-marked fish than in unmarked fish. Only one hatchery was found free of infection during the 3 years covered by the investigation. This installation had never used raw salmon products in diet.

  20. Proliferation zones in the brain of adult fish Austrolebias (Cyprinodontiform: Rivulidae): a comparative study.

    PubMed

    Fernández, A S; Rosillo, J C; Casanova, G; Olivera-Bravo, S

    2011-08-25

    In contrast with mammals, adult fish brains exhibit an enormous potential to produce new cells. Proliferation zones, however, have been described in only a few species, hindering comparisons among genuses and orders. Here we analyzed brain cell proliferation in annual teleostean fishes Austrolebias (Cyprinodontiform: Rivulidae). Immunocytochemistry against 5-bromo-2'-deoxyuridine (BrdU) was quantitated and mapped 24 h after injection in three species with different phylogenetic positions or habitats. All species had similar brain anatomy and total volume, but olfactory bulbs, torus longitudinalis and cerebellum were of different sizes in different species. Cell proliferation was found throughout the brain. Three-D reconstructions provided evidence for contiguity along the rostro-caudal axis and concentration in the vicinity of the ventricles. Brain regions analyzed exhibited high mitotic activity, and the torus longitudinalis had the highest volume-normalized proliferation index. A. affinis exhibited the highest normalized proliferation indexes in visual regions but the lowest in olfactory bulb. A. reicherti showed an inverse pattern, suggesting that these species have a different hierarchy of sensorial modalities that could be related to phylogeny or habitat. Double immunostaining against BrdU and cell-type specific markers was performed to determine the fate of proliferating cells. A widespread gliogenesis was evidenced. Few cells positive for both BrdU and the neuronal marker HuC/D were found in the brain of the three species, demonstrating neurogenesis in the adult Austrolebias brain. Summarizing, adult members of the three species showed similar brain anatomy and cell proliferation patterns. Among species, volume-normalized proliferation indexes varied in regions involved in different sensory modalities. To our knowledge, this is the first report showing proliferating cells with neuronal markers as earlier as 24 h after BrdU injection.

  1. Population Pharmacokinetics of Benznidazole in Adult Patients with Chagas Disease

    PubMed Central

    Aldasoro, E.; Guerrero, L.; Posada, E.; Serret, N.; Mejía, T.; Urbina, J. A.; Gascón, J.

    2015-01-01

    The aim of the present study was to build a population pharmacokinetic (popPK) model to characterize benznidazole (BNZ) pharmacokinetics in adults with chronic Chagas disease. This study was a prospective, open-label, single-center clinical trial approved by the local ethics committee. Patients received BNZ at 2.5 mg/kg of body weight/12 h (Abarax, Elea Laboratory, Argentina) for 60 days. Plasma BNZ samples were taken several times during the study and analyzed by high-performance liquid chromatography with UV-visible detection (HPLC-UV). The popPK analysis was done with NONMEMv.7.3. Demographic and biological data were tested as covariates. Intraindividual, interoccasion, and residual variabilities were modeled. Internal and external validations were completed to assess the robustness of the model. Later on, simulations were performed to generate BNZ concentration-time course profiles for different dosage regimens. A total of 358 plasma BNZ concentrations from 39 patients were included in the analysis. A one-compartment PK model characterized by clearance (CL/F) and the apparent volume of distribution (V/F), with first-order absorption (Ka) and elimination, adequately described the data (CL/F, 1.73 liters/h; V/F, 89.6 liters; and Ka, 1.15 h−1). No covariates were found to be significant for CL/F and V/F. Internal and external validations of the final model showed adequate results. Data from simulations revealed that a dose of 2.5 mg/kg/12 h might lead to overexposure in most patients. A lower dose (2.5 mg/kg/24 h) was able to achieve trough BNZ plasma concentrations within the accepted therapeutic range of 3 to 6 mg/liter. In summary, we developed a population PK model for BNZ in adults with chronic Chagas disease. Dosing simulations showed that a BNZ dose of 2.5 mg/kg/24 h will adequately keep BNZ trough plasma concentrations within the recommended target range for the majority of patients. (This study has been registered at EudraCT under number 2011

  2. Compensatory mechanisms in fish populations: An EPRI research plan: Final report

    SciTech Connect

    Otto, R.G.

    1987-09-01

    This is a plan for Industry-sponsored research on compensation in fish populations impacted at steam-electric or hydro-power facilities. Compensation encompasses processes by which fishes self-regulate rates of reproduction and mortality as means of offsetting those impacts. EPRI's goal is the synthesis of a quantitative model sufficient to predict the direction and relative magnitude of fish population response to anticipated site specific impacts. Two parallel and interactive research efforts are proposed to meet this goal, a Key Species Program and a Fellowship Program. Both are empirical programs, the first emphasizing the generation of new data sets tailored to the needs of the modeling framework and the second testing and expanding the concepts on which the models are based. The Key Species Program is a series of studies of selected species chosen to represent the range of life history strategies encompassed by the modeling framework. The primary research activity is measurement of key life table parameters (reproduction, growth and mortality) across the geographic range of the test species and under circumstances in which the size or structure of the target populations can be manipulated. The Fellowship Program is a basic research effort to be conducted by senior graduate students working in the area of population dynamics. The Program relies on an oversight group of senior academic and industry scientists to set topical goals for research, oversee the selection and implementation of projects and assist with the consolidation and integration of outputs into the larger predictive framework provided by the Key Species studies.

  3. Diploidized eggs reprogram adult somatic cell nuclei to pluripotency in nuclear transfer in medaka fish (Oryzias latipes).

    PubMed

    Bubenshchikova, Ekaterina; Kaftanovskaya, Elena; Motosugi, Nami; Fujimoto, Takafumi; Arai, Katsutoshi; Kinoshita, Masato; Hashimoto, Hisashi; Ozato, Kenjiro; Wakamatsu, Yuko

    2007-12-01

    Reprogramming of adult somatic cell nuclei to pluripotency has been unsuccessful in non-mammalian animals, primarily because of chromosomal aberrations in nuclear transplants, which are considered to be caused by asynchrony between the cell cycles of the recipient egg and donor nucleus. In order to normalize the chromosomal status, we used diploidized eggs by retention of second polar body release, instead of enucleated eggs, as recipients in nuclear transfer of primary culture cells from the caudal fin of adult green fluorescent protein gene (GFP) transgenic medaka fish (Oryzias latipes). We found that 2.7% of the reconstructed embryos grew into adults that expressed GFP in various tissues in the same pattern as in the donor fish. Moreover, these fish were diploid, fertile and capable of passing the marker gene to the next generation in Mendelian fashion. We hesitate to call these fish 'clones' because we used non-enucleated eggs as recipients; in effect, they may be chimeras consisting of cells derived from diploid recipient nuclei and donor nuclei. In either case, fish adult somatic cell nuclei were reprogrammed to pluripotency and differentiated into a variety of cell types including germ cells via the use of diploidized recipient eggs.

  4. Intersex in fishes and amphibians: population implications, prevalence, mechanisms and molecular biomarkers.

    PubMed

    Abdel-Moneim, Ahmed; Coulter, David P; Mahapatra, Cecon T; Sepúlveda, Maria S

    2015-11-01

    Intersex is defined as the abnormal presence of both testicular and ovarian cells in gonads of gonochoristic animals. Its occurrence is widespread and reports on its presence in the gonads of vertebrates continues to increase. In this review, we use standardized terminology to summarize the current knowledge of intersex in gonochoristic fishes and amphibians. We describe the different indices that have been used to assess the severity of intersex and synthesize reports discussing the prevalence of intersex in relation to different types of pollutants. In addition, we evaluate the geographic distribution and chronology of the reported cases of intersex in fishes and amphibians, their pathological descriptions and severity and discuss species sensitivities. We also summarize molecular biomarkers that have been tested for early detection of intersex in wild populations and highlight additional biomarkers that target molecular pathways involved in gonadal development that require further investigation for use in the diagnosis of intersex. Finally, we discuss the needs for future research in this field.

  5. Omics and Environmental Science Genomic Approaches With Natural Fish Populations From Polluted Environments

    PubMed Central

    Bozinovic, Goran; Oleksiak, Marjorie F.

    2010-01-01

    Transcriptomics and population genomics are two complementary genomic approaches that can be used to gain insight into pollutant effects in natural populations. Transcriptomics identify altered gene expression pathways while population genomics approaches more directly target the causative genomic polymorphisms. Neither approach is restricted to a pre-determined set of genes or loci. Instead, both approaches allow a broad overview of genomic processes. Transcriptomics and population genomic approaches have been used to explore genomic responses in populations of fish from polluted environments and have identified sets of candidate genes and loci that appear biologically important in response to pollution. Often differences in gene expression or loci between polluted and reference populations are not conserved among polluted populations suggesting a biological complexity that we do not yet fully understand. As genomic approaches become less expensive with the advent of new sequencing and genotyping technologies, they will be more widely used in complimentary studies. However, while these genomic approaches are immensely powerful for identifying candidate gene and loci, the challenge of determining biological mechanisms that link genotypes and phenotypes remains. PMID:21072843

  6. Respiratory pattern in an adult population of dystrophic patients.

    PubMed

    D'Angelo, M G; Romei, M; Lo Mauro, A; Marchi, E; Gandossini, S; Bonato, S; Comi, G P; Magri, F; Turconi, A C; Pedotti, A; Bresolin, N; Aliverti, A

    2011-07-15

    We studied respiratory function and Chest Wall kinematics in a large population of adult patients affected by slow course muscular dystrophies such as Limb-Girdle Muscular Dystrophy (LGMD, n=38), Becker Muscular Dystrophy (BMD, n=20) and Facio-Scapulo Humeral Dystrophy (FSHD, n=30), through standard spirometry and through the Optoelectronic Plethysmography, to measure the thoraco-abdominal motion during Quiet Breathing and Slow Vital Capacity maneuvers. Within the restrictive pulmonary syndrome characterizing LGMD and FSHD, several different thoraco-abdominal patterns compared to those of healthy subjects were present in the more advanced stages of the disease. These differences were present in the seated position, during the execution of a maximal maneuver such as Slow Vital Capacity. A global respiratory (both inspiratory and expiratory) muscle involvement was more pronounced in the LGMD and FSHD than in the BMD patients, and a significant reduction of abdominal contribution in wheelchair bound patients was observed. In conclusion, OEP technique is able to reveal mild initial modifications in the respiratory muscles in FSHD and LGMD patients, which could be helpful for functional and new therapeutic strategy evaluation.

  7. Perceived stress and mortality in a Taiwanese older adult population.

    PubMed

    Vasunilashorn, Sarinnapha; Glei, Dana A; Weinstein, Maxine; Goldman, Noreen

    2013-11-01

    Perceived stress is associated with poor health outcomes including negative affect, increased susceptibility to the common cold and cardiovascular disease; the consequences of perceived stress for mortality, however, have received less attention. This study characterizes the relationship between perceived stress and 11-year mortality in a population of Taiwanese adults aged 53+ years. Using the Survey of Health and Living Status of the Near Elderly and Elderly of Taiwan, we calculated a composite measure of perceived stress based on six items pertaining to the health, financial situation, and occupation of the respondents and their families. Proportional hazard models were used to determine whether perceived stress predicted mortality. After adjusting for sociodemographic factors only, we found that a one standard deviation increase in perceived stress was associated with a 19% increase in all-cause mortality risk during the 11-year follow-up period (hazard ratio, HR = 1.19, 95% confidence interval, CI 1.13-1.26). The relationship was greatly attenuated when perceptions of stress regarding health were excluded, and was not significant after adjusting for medical conditions, mobility limitations and depressive symptoms. We conclude that the association between perceived stress and mortality is explained by an individual's current health; however, our data do not allow us to distinguish between two possible interpretations of this conclusion: (a) the relationship between perceived stress and mortality is spurious, or (b) poor health acts as the mediator.

  8. Predators inhibit brain cell proliferation in natural populations of electric fish, Brachyhypopomus occidentalis.

    PubMed

    Dunlap, Kent D; Tran, Alex; Ragazzi, Michael A; Krahe, Rüdiger; Salazar, Vielka L

    2016-02-10

    Compared with laboratory environments, complex natural environments promote brain cell proliferation and neurogenesis. Predators are one important feature of many natural environments, but, in the laboratory, predatory stimuli tend to inhibit brain cell proliferation. Often, laboratory predatory stimuli also elevate plasma glucocorticoids, which can then reduce brain cell proliferation. However, it is unknown how natural predators affect cell proliferation or whether glucocorticoids mediate the neurogenic response to natural predators. We examined brain cell proliferation in six populations of the electric fish, Brachyhypopomus occidentalis, exposed to three forms of predator stimuli: (i) natural variation in the density of predatory catfish; (ii) tail injury, presumably from predation attempts; and (iii) the acute stress of capture. Populations with higher predation pressure had lower density of proliferating (PCNA+) cells, and fish with injured tails had lower proliferating cell density than those with intact tails. However, plasma cortisol did not vary at the population level according to predation pressure or at the individual level according to tail injury. Capture stress significantly increased cortisol, but only marginally decreased cell proliferation. Thus, it appears that the presence of natural predators inhibits brain cell proliferation, but not via mechanisms that depend on changes in basal cortisol levels. This study is the first demonstration of predator-induced alteration of brain cell proliferation in a free-living vertebrate.

  9. Levels of Engagement and Barriers to Physical Activity in a Population of Adults with Learning Disabilities

    ERIC Educational Resources Information Center

    Hawkins, Andrew; Look, Roger

    2006-01-01

    This study examined levels of, and barriers to, physical activity in a population of 19 adults with learning disabilities living in community supported accommodation, using diary records and semi-structured interviews with staff. The levels of physical activity were higher in the sample population than previous figures for adults with learning…

  10. Crisis Model for Older Adults: Special Considerations for an Aging Population

    ERIC Educational Resources Information Center

    Jungers, Christin M.; Slagel, Leslie

    2009-01-01

    As the U.S. population ages, counselors must begin structuring their interactions to meet the unique needs of older adults, especially in the area of crisis intervention. The purposes of this article are to draw attention to the rapidly growing, often disregarded older population and to introduce the Crisis Model for Older Adults (CM-OA), an…

  11. Indirect effects of impoundment on migrating fish: temperature gradients in fish ladders slow dam passage by adult Chinook salmon and steelhead.

    PubMed

    Caudill, Christopher C; Keefer, Matthew L; Clabough, Tami S; Naughton, George P; Burke, Brian J; Peery, Christopher A

    2013-01-01

    Thermal layering in reservoirs upstream from hydroelectric dams can create temperature gradients in fishways used by upstream migrating adults. In the Snake River, Washington, federally-protected adult salmonids (Oncorhynchus spp.) often encounter relatively cool water in dam tailraces and lower ladder sections and warmer water in the upstream portions of ladders. Using radiotelemetry, we examined relationships between fish passage behavior and the temperature difference between the top and bottom of ladders (∆T) at four dams over four years. Some spring Chinook salmon (O. tshawytscha) experienced ∆T ≥ 0.5 °C. Many summer and fall Chinook salmon and summer steelhead (O. mykiss) experienced ∆T ≥ 1.0 °C, and some individuals encountered ΔT > 4.0°C. As ΔT increased, migrants were consistently more likely to move down fish ladders and exit into dam tailraces, resulting in upstream passage delays that ranged from hours to days. Fish body temperatures equilibrated to ladder temperatures and often exceeded 20°C, indicating potential negative physiological and fitness effects. Collectively, the results suggest that gradients in fishway water temperatures present a migration obstacle to many anadromous migrants. Unfavorable temperature gradients may be common at reservoir-fed fish passage facilities, especially those with seasonal thermal layering or stratification. Understanding and managing thermal heterogeneity at such sites may be important for ensuring efficient upstream passage and minimizing stress for migratory, temperature-sensitive species.

  12. Indirect Effects of Impoundment on Migrating Fish: Temperature Gradients in Fish Ladders Slow Dam Passage by Adult Chinook Salmon and Steelhead

    PubMed Central

    Caudill, Christopher C.; Keefer, Matthew L.; Clabough, Tami S.; Naughton, George P.; Burke, Brian J.; Peery, Christopher A.

    2013-01-01

    Thermal layering in reservoirs upstream from hydroelectric dams can create temperature gradients in fishways used by upstream migrating adults. In the Snake River, Washington, federally-protected adult salmonids (Oncorhynchus spp.) often encounter relatively cool water in dam tailraces and lower ladder sections and warmer water in the upstream portions of ladders. Using radiotelemetry, we examined relationships between fish passage behavior and the temperature difference between the top and bottom of ladders (∆T) at four dams over four years. Some spring Chinook salmon (O. tshawytscha) experienced ∆T ≥ 0.5 °C. Many summer and fall Chinook salmon and summer steelhead (O. mykiss) experienced ∆T ≥ 1.0 °C, and some individuals encountered ΔT > 4.0°C. As ΔT increased, migrants were consistently more likely to move down fish ladders and exit into dam tailraces, resulting in upstream passage delays that ranged from hours to days. Fish body temperatures equilibrated to ladder temperatures and often exceeded 20°C, indicating potential negative physiological and fitness effects. Collectively, the results suggest that gradients in fishway water temperatures present a migration obstacle to many anadromous migrants. Unfavorable temperature gradients may be common at reservoir-fed fish passage facilities, especially those with seasonal thermal layering or stratification. Understanding and managing thermal heterogeneity at such sites may be important for ensuring efficient upstream passage and minimizing stress for migratory, temperature-sensitive species. PMID:24392020

  13. Does mobility explain variation in colonisation and population recovery among stream fishes?

    USGS Publications Warehouse

    Angermeier, Paul L.; Albanese, Brett; Peterson, James T.

    2009-01-01

    1. Colonisation and population recovery are crucial to species persistence in environmentally variable ecosystems, but are poorly understood processes. After documenting movement rates for several species of stream fish, we predicted that this variable would influence colonisation rates more strongly than local abundance, per cent occupancy, body size and taxonomic family. We also predicted that populations of species with higher movement rates would recover more rapidly than species with lower movement rates and that assemblage structure would change accordingly. 2. To test these predictions, we removed fishes from a headwater and a mainstem creek in southwest Virginia and monitored colonisation over a 2-year period. Using an information–theoretic approach, we evaluated the relative plausibility of 15 alternative models containing different combinations of our predictor variables. Our best-supported model contained movement rate and abundance and was 41 times more likely to account for observed patterns in colonisation rates than the next-best model. Movement rate and abundance were both positively related to colonisation rates and explained 88% of the variation in colonisation rates among species. 3. Population recovery, measured as the per cent of initial abundance restored, was also positively associated with movement rate. One species recovered within 3 months, most recovered within 2 years, but two species still had not recovered after 2 years. Despite high variation in recovery, the removal had only a slight impact on assemblage structure because species that were abundant in pre-removal samples were also abundant in post-removal samples. 4. The significance of interspecific variation in colonisation and recovery rates has been underappreciated because of the widely documented recovery of stream fish assemblages following fish kills and small-scale experimental defaunations. Our results indicate that recovery of the overall assemblage does not imply

  14. Visual Basic, Excel-based fish population modeling tool - The pallid sturgeon example

    USGS Publications Warehouse

    Moran, Edward H.; Wildhaber, Mark L.; Green, Nicholas S.; Albers, Janice L.

    2016-02-10

    The model presented in this report is a spreadsheet-based model using Visual Basic for Applications within Microsoft Excel (http://dx.doi.org/10.5066/F7057D0Z) prepared in cooperation with the U.S. Army Corps of Engineers and U.S. Fish and Wildlife Service. It uses the same model structure and, initially, parameters as used by Wildhaber and others (2015) for pallid sturgeon. The difference between the model structure used for this report and that used by Wildhaber and others (2015) is that variance is not partitioned. For the model of this report, all variance is applied at the iteration and time-step levels of the model. Wildhaber and others (2015) partition variance into parameter variance (uncertainty about the value of a parameter itself) applied at the iteration level and temporal variance (uncertainty caused by random environmental fluctuations with time) applied at the time-step level. They included implicit individual variance (uncertainty caused by differences between individuals) within the time-step level.The interface developed for the model of this report is designed to allow the user the flexibility to change population model structure and parameter values and uncertainty separately for every component of the model. This flexibility makes the modeling tool potentially applicable to any fish species; however, the flexibility inherent in this modeling tool makes it possible for the user to obtain spurious outputs. The value and reliability of the model outputs are only as good as the model inputs. Using this modeling tool with improper or inaccurate parameter values, or for species for which the structure of the model is inappropriate, could lead to untenable management decisions. By facilitating fish population modeling, this modeling tool allows the user to evaluate a range of management options and implications. The goal of this modeling tool is to be a user-friendly modeling tool for developing fish population models useful to natural resource

  15. Pigment patterns in adult fish result from superimposition of two largely independent pigmentation mechanisms.

    PubMed

    Ceinos, Rosa M; Guillot, Raúl; Kelsh, Robert N; Cerdá-Reverter, José M; Rotllant, Josep

    2015-03-01

    Dorso-ventral pigment pattern differences are the most widespread pigmentary adaptations in vertebrates. In mammals, this pattern is controlled by regulating melanin chemistry in melanocytes using a protein, agouti-signalling peptide (ASIP). In fish, studies of pigment patterning have focused on stripe formation, identifying a core striping mechanism dependent upon interactions between different pigment cell types. In contrast, mechanisms driving the dorso-ventral countershading pattern have been overlooked. Here, we demonstrate that, in fact, zebrafish utilize two distinct adult pigment patterning mechanisms - an ancient dorso-ventral patterning mechanism, and a more recent striping mechanism based on cell-cell interactions; remarkably, the dorso-ventral patterning mechanism also utilizes ASIP. These two mechanisms function largely independently, with resultant patterns superimposed to give the full pattern.

  16. Genetic structuring among silverside fish (Atherinella brasiliensis) populations from different Brazilian regions

    NASA Astrophysics Data System (ADS)

    da Silva Cortinhas, Maria Cristina; Kersanach, Ralf; Proietti, Maíra; Dumont, Luiz Felipe Cestari; D'Incao, Fernando; Lacerda, Ana Luzia F.; Prata, Pedro Sanmartin; Matoso, Daniele Aparecida; Noleto, Rafael Bueno; Ramsdorf, Wanessa; Boni, Talge Aiex; Prioli, Alberto José; Cestari, Marta Margarete

    2016-09-01

    Estuaries are dynamic environments, key for the survival of innumerous ecologically or economically important fish species. Among these species are Neotropical silversides (Atherinella brasiliensis), which are resident and abundant in Brazilian estuaries and used as a complementary source of income and food for local communities. To better understand silverside populations in Brazil, we evaluated the genetic diversity, structure and demography of fish sampled at six estuaries from the northeastern to the southern coast, using Random Amplified Polymorphic DNA and mitochondrial DNA (D-loop) markers. High haplotype diversities (h ranging from 0.75 to 0.99) were found in all populations except Carapebus, located in Southeast Brazil (h = 0.54). A total of 69 mtDNA haplotypes were found, with Itaparica (Northeast Brazil) and Carapebus presenting only exclusive haplotypes, while some were shared among populations in the South. Strong regional structure was observed, with very high differentiation between Itaparica and Carapebus, as well as among these two populations and the ones from the Southern region (Paranaguá, Conceição, Camacho and Patos). Among southern areas, low/moderate structure was detected. Most populations showed unimodal mismatch distributions indicating recent demographic expansion, while Carapebus presented a multimodal distribution characteristic of a stable or bottlenecked population. Times since possible population expansion were highest in Itaparica (32,500 ya) and Carapebus (29,540 ya), while in the Southern region longest time was observed at Conceição (25,540 ya) and shortest at Patos (9720 ya). In a general manner, haplotype diversities were directly related to times since population expansions; again, Carapebus was the exception, displaying long time since expansion but low diversity, possibly due to a recent bottleneck caused by the isolation and human impacts this lagoon is subject to. Isolation by Distance was significant for Itaparica

  17. Diet dynamics of the adult piscivorous fish community in Spirit Lake, Iowa, USA 1995-1997

    USGS Publications Warehouse

    Liao, H.; Pierce, C.L.; Larscheid, J.G.

    2002-01-01

    Diets of adults of six important piscivorous fish species, black crappie Pomoxis nigromaculatus, largemouth bass Micropterus salmoides, northern pike Esox lucius, smallmouth bass Micropterus dolomieui, walleye Stizostedion vitreum, and yellow perch Perca flavescens were quantified in Spirit Lake, Iowa, USA from May to October in 1995-1997. Forty-one prey taxa were found in the diets of these species, including 19 species of fish. The most important prey taxa overall were yellow perch, amphipods and dipterans. Diets of northern pike and walleye were dominated by yellow perch. Largemouth bass diets included large percentages of both yellow perch and black bullhead Ameiurus melas. Smallmouth bass diets included large percentages of both yellow perch and crayfish. Black crappie and yellow perch diets were dominated by invertebrates, primarily amphipods and dipterans. There were pronounced differences in diets among species, among size classes within species and over time. Most of the dominant prey taxa we documented in the diets of piscivorous species were in accordance with previous studies, but a few deviated significantly from expectations. Many of the temporal diet changes were asynchronous among piscivorous species and size classes, suggesting different responses to common prey resources over time.

  18. Population Connectivity and Phylogeography of a Coastal Fish, Atractoscion aequidens (Sciaenidae), across the Benguela Current Region: Evidence of an Ancient Vicariant Event

    PubMed Central

    Henriques, Romina; Potts, Warren M.; Santos, Carmen V.; Sauer, Warwick H. H.; Shaw, Paul W.

    2014-01-01

    Contemporary patterns of genetic diversity and population connectivity within species can be influenced by both historical and contemporary barriers to gene flow. In the marine environment, present day oceanographic features such as currents, fronts and upwelling systems can influence dispersal of eggs/larvae and/juveniles/adults, shaping population substructuring. The Benguela Current system in the southeastern Atlantic is one of the oldest upwelling systems in the world, and provides a unique opportunity to investigate the relative influence of contemporary and historical mechanisms shaping the evolutionary history of warm-temperate fish species. Using the genetic variation in the mitochondrial DNA Control Region and eight nuclear microsatellite DNA loci, we identified the presence of two highly divergent populations in a vagile and warm-temperate fish species, Atractoscion aequidens, across the Benguela region. The geographical distributions of the two populations, on either side of the perennial upwelling cell, suggest a strong correlation between the oceanographic features of the system and the breakdown of gene flow within this species. Genetic divergence (mtDNA φST = 0.902, microsatellite FST = 0.055: probability of genetic homogeneity for either marker = p<0.001), absence of migrants (less than 1% per generation) between populations and coalescent estimates of time since most recent common ancestor suggest that the establishment of the main oceanographic features of the system (2 million years ago), particularly the strengthening and position of the perennial upwelling cell, is the most likely mechanism behind the observed isolation. Concordance between mitochondrial and nuclear genetic markers indicates that isolation and divergence of the northern and southern Benguela populations of A. aequidens occurred deep in the past and has continued to the present day. These findings suggest that the Benguela Current system may constitute an ancient

  19. Population connectivity and phylogeography of a coastal fish, Atractoscion aequidens (Sciaenidae), across the Benguela Current region: evidence of an ancient vicariant event.

    PubMed

    Henriques, Romina; Potts, Warren M; Santos, Carmen V; Sauer, Warwick H H; Shaw, Paul W

    2014-01-01

    Contemporary patterns of genetic diversity and population connectivity within species can be influenced by both historical and contemporary barriers to gene flow. In the marine environment, present day oceanographic features such as currents, fronts and upwelling systems can influence dispersal of eggs/larvae and/juveniles/adults, shaping population substructuring. The Benguela Current system in the southeastern Atlantic is one of the oldest upwelling systems in the world, and provides a unique opportunity to investigate the relative influence of contemporary and historical mechanisms shaping the evolutionary history of warm-temperate fish species. Using the genetic variation in the mitochondrial DNA Control Region and eight nuclear microsatellite DNA loci, we identified the presence of two highly divergent populations in a vagile and warm-temperate fish species, Atractoscion aequidens, across the Benguela region. The geographical distributions of the two populations, on either side of the perennial upwelling cell, suggest a strong correlation between the oceanographic features of the system and the breakdown of gene flow within this species. Genetic divergence (mtDNA φ ST = 0.902, microsatellite F ST = 0.055: probability of genetic homogeneity for either marker = p<0.001), absence of migrants (less than 1% per generation) between populations and coalescent estimates of time since most recent common ancestor suggest that the establishment of the main oceanographic features of the system (2 million years ago), particularly the strengthening and position of the perennial upwelling cell, is the most likely mechanism behind the observed isolation. Concordance between mitochondrial and nuclear genetic markers indicates that isolation and divergence of the northern and southern Benguela populations of A. aequidens occurred deep in the past and has continued to the present day. These findings suggest that the Benguela Current system may constitute an ancient and

  20. Seasonal weather patterns drive population vital rates and persistence in a stream fish.

    PubMed

    Kanno, Yoichiro; Letcher, Benjamin H; Hitt, Nathaniel P; Boughton, David A; Wofford, John E B; Zipkin, Elise F

    2015-05-01

    Climate change affects seasonal weather patterns, but little is known about the relative importance of seasonal weather patterns on animal population vital rates. Even when such information exists, data are typically only available from intensive fieldwork (e.g., mark-recapture studies) at a limited spatial extent. Here, we investigated effects of seasonal air temperature and precipitation (fall, winter, and spring) on survival and recruitment of brook trout (Salvelinus fontinalis) at a broad spatial scale using a novel stage-structured population model. The data were a 15-year record of brook trout abundance from 72 sites distributed across a 170-km-long mountain range in Shenandoah National Park, Virginia, USA. Population vital rates responded differently to weather and site-specific conditions. Specifically, young-of-year survival was most strongly affected by spring temperature, adult survival by elevation and per-capita recruitment by winter precipitation. Low fall precipitation and high winter precipitation, the latter of which is predicted to increase under climate change for the study region, had the strongest negative effects on trout populations. Simulations show that trout abundance could be greatly reduced under constant high winter precipitation, consistent with the expected effects of gravel-scouring flows on eggs and newly hatched individuals. However, high-elevation sites would be less vulnerable to local extinction because they supported higher adult survival. Furthermore, the majority of brook trout populations are projected to persist if high winter precipitation occurs only intermittently (≤3 of 5 years) due to density-dependent recruitment. Variable drivers of vital rates should be commonly found in animal populations characterized by ontogenetic changes in habitat, and such stage-structured effects may increase population persistence to changing climate by not affecting all life stages simultaneously. Yet, our results also demonstrate that

  1. Correlation of Osteoporosis and Calcium Urolithiasis in Adult Population

    PubMed Central

    Bijelic, Radojka; Milicevic, Snjezana; Balaban, Jagoda

    2016-01-01

    , the share of those who do not have normal findings is higher in the elderly population. Conclusion: Our study has just shown that in adult patients with calcium urolithiasis osteoporosis is more prevalent in older patients and more pronounced in patients with calcium urolithiasis in relation to the population without the same. PMID:26980936

  2. Estimate of intake of sulfites in the Belgian adult population.

    PubMed

    Vandevijvere, S; Temme, E; Andjelkovic, M; De Wil, M; Vinkx, C; Goeyens, L; Van Loco, J

    2010-08-01

    An exposure assessment was performed to estimate the usual daily intake of sulfites in the Belgian adult population. Food consumption data were retrieved from the national food consumption survey. In a first step, individual food consumption data were multiplied with the maximum permitted use levels for sulfites, expressed as sulphur dioxide, per food group (Tier 2). In a second step, on the basis of a literature review of the occurrence of sulfites in different foods, the results of the Tier 2 exposure assessment and available occurrence data from the control programme of the competent authority, a refined list of foods was drafted for the quantification of sulphite. Quantification of sulphite was performed by a high-performance ion chromatography method with eluent conductivity detector in beers and potato products. Individual food consumption data were then multiplied with the actual average concentrations of sulfite per food group, or the maximum permitted levels in case actual levels were not available (partial Tier 3). Usual intakes were calculated using the Nusser method. The mean intake of sulfites was 0.34 mg kg(-1) bw day(-1) (Tier 2), corresponding to 49% of the acceptable daily intake (ADI) and 0.19 mg kg(-1) bw day(-1), corresponding to 27% of the ADI (partial Tier 3). The food group contributing most to the intake of sulfites was wines. The results showed that the intake of sulfites is likely to be below the ADI in Belgium. However, there are indications that high consumers of wine have an intake around the ADI.

  3. Community-Based Adult Education for the Fisherwomen of Rajapalyam Fishing Village in Tuticorin, Southeast Coast of India

    ERIC Educational Resources Information Center

    Patterson, Jamila; Linden, Eva; Bierbrier, Christin; Lofgren, Inger; Edward, J. K. Patterson

    2008-01-01

    Rajapalyam village is located in the Tuticorin district along the biodiversity rich Gulf of Mannar coast in southeastern India. The people of this village are economically backward and most of the men are engaged in fishing. The fisherwomen of this village are less literate than the men, or illiterate. Adult education has been introduced to the…

  4. Population structure among octocoral adults and recruits identifies scale dependent patterns of population isolation in The Bahamas

    PubMed Central

    Porto-Hannes, Isabel

    2015-01-01

    Patterns of dispersal and connectivity of the Caribbean gorgonian Antillogorgia elisabethae in The Bahamas were assessed in both adults and recently settled recruits from 13 sites using microsatellite loci. Adult populations along the Little Bahama Bank (LBB) exhibited a clear pattern of isolation by distance (IBD) which described 86% of the variance in pairwise genetic distances. Estimates of dispersal based on the IBD model suggested dispersal distances along the LBB on the order of 100 m. Increasing the spatial scale to include sites separated by open ocean generated an apparent IBD signal but the relationship had a greater slope and explained less of the variance. This relationship with distance reflected both stepping stone based IBD and regional differentiation probably created by ocean currents and barriers to dispersal that are correlated with geographic distance. Analysis of recruits from 4 sites on the LBB from up to 6 years did not detect differences between years nor differences with adult populations. The result suggests that neither selection on recruits nor inter-annual variation in dispersal affected adult population structure. Assignment tests of recruits indicated the most likely sources of the recruits were the local or adjacent populations. Most of the patterning in population structure in the northern Bahamas can be explained by geographic distance and oceanographic connectivity. Recognition of these complex patterns is important in developing management plans for A. elisabethae and in understanding the effects of disturbance to adult populations of A. elisabethae and similar species with limited dispersal. PMID:26157606

  5. Early detection of nonnative alleles in fish populations: When sample size actually matters

    USGS Publications Warehouse

    Croce, Patrick Della; Poole, Geoffrey C.; Payne, Robert A.; Gresswell, Bob

    2017-01-01

    Reliable detection of nonnative alleles is crucial for the conservation of sensitive native fish populations at risk of introgression. Typically, nonnative alleles in a population are detected through the analysis of genetic markers in a sample of individuals. Here we show that common assumptions associated with such analyses yield substantial overestimates of the likelihood of detecting nonnative alleles. We present a revised equation to estimate the likelihood of detecting nonnative alleles in a population with a given level of admixture. The new equation incorporates the effects of the genotypic structure of the sampled population and shows that conventional methods overestimate the likelihood of detection, especially when nonnative or F-1 hybrid individuals are present. Under such circumstances—which are typical of early stages of introgression and therefore most important for conservation efforts—our results show that improved detection of nonnative alleles arises primarily from increasing the number of individuals sampled rather than increasing the number of genetic markers analyzed. Using the revised equation, we describe a new approach to determining the number of individuals to sample and the number of diagnostic markers to analyze when attempting to monitor the arrival of nonnative alleles in native populations.

  6. Genetic diversity despite population collapse in a critically endangered marine fish: the smalltooth sawfish (Pristis pectinata).

    PubMed

    Chapman, Demian D; Simpfendorfer, Colin A; Wiley, Tonya R; Poulakis, Gregg R; Curtis, Caitlin; Tringali, Michael; Carlson, John K; Feldheim, Kevin A

    2011-01-01

    Sawfish (family Pristidae) are among the most critically endangered marine fish in the world, yet very little is known about how genetic bottlenecks, genetic drift, and inbreeding depression may be affecting these elasmobranchs. In the US Atlantic, the smalltooth sawfish (Pristis pectinata) has declined to 1-5% of its abundance in the 1900s, and its core distribution has contracted to southwest Florida. We used 8 polymorphic microsatellite markers to show that this remnant population still exhibits high genetic diversity in terms of average allelic richness (18.23), average alleles per locus (18.75, standard deviation [SD] 6.6) and observed heterozygosity (0.43-0.98). Inbreeding is rare (mean individual internal relatedness = -0.02, SD 0.14; F(IS) = -0.011, 95% confidence interval [CI] = -0.039 to 0.011), even though the estimated effective population size (N(e)) is modest (250-350, 95% CI = 142-955). Simulations suggest that the remnant smalltooth sawfish population will probably retain >90% of its current genetic diversity over the next century even at the lower estimate of N(e). There is no evidence of a genetic bottleneck accompanying last century's demographic bottleneck, and we discuss hypotheses that could explain this. We also discuss features of elasmobranch life history and population biology that could make them less vulnerable than other large marine vertebrates to genetic change associated with reduced population size.

  7. Embryonic IGF2 Expression Is Not Associated with Offspring Size among Populations of a Placental Fish

    PubMed Central

    Schrader, Matthew; Travis, Joseph

    2012-01-01

    In organisms that provision young between fertilization and birth, mothers and their developing embryos are expected to be in conflict over embryonic growth. In mammalian embryos, the expression of Insulin-like growth factor II (IGF2) plays a key role in maternal-fetal interactions and is thought to be a focus of maternal-fetal conflict. Recent studies have suggested that IGF2 is also a focus of maternal-fetal conflict in placental fish in the family Poeciliidae. However, whether the expression of IGF2 influences offspring size, the trait over which mothers and embryos are likely to be in conflict, has not been assessed in a poeciliid. We tested whether embryonic IGF2 expression varied among four populations of a placental poeciliid that display large and consistent differences in offspring size at birth. We found that IGF2 expression varied significantly among embryonic stages with expression being 50% higher in early stage embryos than late stage embryos. There were no significant differences among populations in IGF2 expression; small differences in expression between population pairs with different offspring sizes were comparable in magnitude to those between population pairs with the same offspring sizes. Our results indicate that variation in IGF2 transcript abundance does not contribute to differences in offspring size among H. formosa populations. PMID:23029026

  8. Population genetic structure of Earth's largest fish, the whale shark (Rhincodon typus).

    PubMed

    Castro, A L F; Stewart, B S; Wilson, S G; Hueter, R E; Meekan, M G; Motta, P J; Bowen, B W; Karl, S A

    2007-12-01

    Large pelagic vertebrates pose special conservation challenges because their movements generally exceed the boundaries of any single jurisdiction. To assess the population structure of whale sharks (Rhincodon typus), we sequenced complete mitochondrial DNA control regions from individuals collected across a global distribution. We observed 51 single site polymorphisms and 8 regions with indels comprising 44 haplotypes in 70 individuals, with high haplotype (h = 0.974 +/- 0.008) and nucleotide diversity (pi = 0.011 +/- 0.006). The control region has the largest length variation yet reported for an elasmobranch (1143-1332 bp). Phylogenetic analyses reveal no geographical clustering of lineages and the most common haplotype was distributed globally. The absence of population structure across the Indian and Pacific basins indicates that oceanic expanses and land barriers in Southeast Asia are not impediments to whale shark dispersal. We did, however, find significant haplotype frequency differences (AMOVA, Phi(ST) = 0.107, P < 0.001) principally between the Atlantic and Indo-Pacific populations. In contrast to other recent surveys of globally distributed sharks, we find much less population subdivision and no evidence for cryptic evolutionary partitions. Discovery of the mating and pupping areas of whale sharks is key to further population genetic studies. The global pattern of shared haplotypes in whale sharks provides a compelling argument for development of broad international approaches for management and conservation of Earth's largest fish.

  9. The impact of United States recreational fisheries on marine fish populations.

    PubMed

    Coleman, Felicia C; Figueira, Will F; Ueland, Jeffrey S; Crowder, Larry B

    2004-09-24

    We evaluated the commercial and recreational fishery landings over the past 22 years, first at the national level, then for populations of concern (those that are overfished or experiencing overfishing), and finally by region. Recreational landings in 2002 account for 4% of total marine fish landed in the United States. With large industrial fisheries excluded (e.g., menhaden and pollock), the recreational component rises to 10%. Among populations of concern, recreational landings in 2002 account for 23% of the total nationwide, rising to 38% in the South Atlantic and 64% in the Gulf of Mexico. Moreover, it affects many of the most-valued overfished species-including red drum, bocaccio, and red snapper-all of which are taken primarily in the recreational fishery.

  10. [Advanced approaches to studying the population diversity of marine fishes: new opportunities for fisheries control and management].

    PubMed

    Zelenina, D A; Martinson, Ia T; Ogden, R; Volkov, A A; Zelenina, I A; Carvalho, G R

    2011-12-01

    Recent conceptual and technological advances now enable fisheries geneticists to detect and monitor the dynamics and distribution of marine fish populations more effectively than ever before. Information on the extent of genetically-based divergence among populations, so-called "population diversity", is crucial in the quest to manage exploited living resources sustainably since it endows evolutionary potential in the face of environmental change. The generally limited dialogue between scientists, fisheries managers and policy makers, however, continues to constrain integration of population genetic data into tangible policy applications. Largely drawing on the approach and outputs from a European research project, FishPopTrace, we provide an example how the uncovering of marine fish population diversity enables players from genetics, forensics, management and the policy realm to generate a framework tackling key policy-led questions relating to illegal fishing and traceability. We focus on the use of single-nucleotide polymorphisms (SNPs) in European populations of cod, herring, hake and common sole, and explore how forensics together with a range of analytical approaches, and combined with improved communication of research results to stakeholders, can be used to secure sufficiently robust, tractable and targeted data for effective engagement between science and policy. The essentially binary nature of SNPs, together with generally elevated signals of population discrimination by SNPs under selection, allowed assignment of fish to populations from more areas and with higher certainty than previously possible, reaching standards suitable for use in a court of law. We argue that the use of such tools in enforcement and deterrence, together with the greater integration of population genetic principles and methods into fisheries management, provide tractable elements in the arsenal of tools to achieve sustainable exploitation and conservation of depleted marine fish

  11. Impact of entrainment and impingement on fish populations in the Hudson River estuary. Volume I. Entrainment-impact estimates for six fish populations inhabiting the Hudson River estuary

    SciTech Connect

    Boreman, J.; Barnthouse, L.W.; Vaughn, D.S.; Goodyear, C.P.; Christensen, S.W.; Kumar, K.D.; Kirk, B.L.; Van Winkle, W.

    1982-01-01

    This volume is concerned with the estimation of the direct (or annual) entrainment impact of power plants on populations of striped bass, white perch, Alosa spp. (blueback herring and alewife), American shad, Atlantic tomcod, and bay anchovy in the Hudson River estuary. Entrainment impact results from the killing of fish eggs, larvae, and young juveniles that are contained in the cooling water cycled through a power plant. An Empirical Transport Model (ETM) is presented as the means of estimating a conditional entrainment mortality rate (defined as the fraction of a year class which would be killed due to entrainment in the absence of any other source of mortality). Most of this volume is concerned with the estimation of several parameters required by the ETM: physical input parameters (e.g., power-plant withdrawal flow rates); the longitudinal distribution of ichthyoplankton in time and space; the duration of susceptibility of the vulnerable organisms; the W-factors, which express the ratios of densities of organisms in power plant intakes to densities of organisms in the river; and the entrainment mortality factors (f-factors), which express the probability that an organism will be killed if it is entrained. Once these values are obtained, the ETM is used to estimate entrainment impact for both historical and projected conditions.

  12. Larval retention and connectivity among populations of corals and reef fishes: history, advances and challenges

    NASA Astrophysics Data System (ADS)

    Jones, G. P.; Almany, G. R.; Russ, G. R.; Sale, P. F.; Steneck, R. S.; van Oppen, M. J. H.; Willis, B. L.

    2009-06-01

    The extent of larval dispersal on coral reefs has important implications for the persistence of coral reef metapopulations, their resilience and recovery from an increasing array of threats, and the success of protective measures. This article highlights a recent dramatic increase in research effort and a growing diversity of approaches to the study of larval retention within (self-recruitment) and dispersal among (connectivity) isolated coral reef populations. Historically, researchers were motivated by alternative hypotheses concerning the processes limiting populations and structuring coral reef assemblages, whereas the recent impetus has come largely from the need to incorporate dispersal information into the design of no-take marine protected area (MPA) networks. Although the majority of studies continue to rely on population genetic approaches to make inferences about dispersal, a wide range of techniques are now being employed, from small-scale larval tagging and paternity analyses, to large-scale biophysical circulation models. Multiple approaches are increasingly being applied to cross-validate and provide more realistic estimates of larval dispersal. The vast majority of empirical studies have focused on corals and fishes, where evidence for both extremely local scale patterns of self-recruitment and ecologically significant connectivity among reefs at scales of tens of kilometers (and in some cases hundreds of kilometers) is accumulating. Levels of larval retention and the spatial extent of connectivity in both corals and fishes appear to be largely independent of larval duration or reef size, but may be strongly influenced by geographic setting. It is argued that high levels of both self-recruitment and larval import can contribute to the resilience of reef populations and MPA networks, but these benefits will erode in degrading reef environments.

  13. Habitat Discontinuities Separate Genetically Divergent Populations of a Rocky Shore Marine Fish

    PubMed Central

    Knutsen, Halvor; Jorde, Per Erik

    2016-01-01

    Habitat fragmentation has been suggested to be responsible for major genetic differentiations in a range of marine organisms. In this study, we combined genetic data and environmental information to unravel the relative role of geography and habitat heterogeneity on patterns of genetic population structure of corkwing wrasse (Symphodus melops), a rocky shore species at the northern limit of its distribution range in Scandinavia. Our results revealed a major genetic break separating populations inhabiting the western and southern coasts of Norway. This genetic break coincides with the longest stretch of sand in the whole study area, suggesting habitat fragmentation as a major driver of genetic differentiation of this obligate rocky shore benthic fish in Scandinavia. The complex fjords systems extending along the western coast of Norway appeared responsible for further regional genetic structuring. Our findings indicate that habitat discontinuities may lead to significant genetic fragmentation over short geographical distances, even for marine species with a pelagic larval phase, as for this rocky shore fish. PMID:27706178

  14. Big Spring spinedace and associated fish populations and habitat conditions in Condor Canyon, Meadow Valley Wash, Nevada

    USGS Publications Warehouse

    Jezorek, Ian G.; Connolly, Patrick J.; Munz, Carrie S.; Dixon, Chris

    2011-01-01

    Executive Summary: This project was designed to document habitat conditions and populations of native and non-native fish within the 8-kilometer Condor Canyon section of Meadow Valley Wash, Nevada, with an emphasis on Big Spring spinedace (Lepidomeda mollispinis pratensis). Other native fish present were speckled dace (Rhinichthys osculus) and desert sucker (Catostomus clarki). Big Spring spinedace were known to exist only within this drainage and were known to have been extirpated from a portion of their former habitat located downstream of Condor Canyon. Because of this extirpation and the limited distribution of Big Spring spinedace, the U.S. Fish and Wildlife Service listed this species as threatened under the Endangered Species Act in 1985. Prior to our effort, little was known about Big Spring spinedace populations or life histories and habitat associations. In 2008, personnel from the U.S. Geological Survey's Columbia River Research Laboratory began surveys of Meadow Valley Wash in Condor Canyon. Habitat surveys characterized numerous variables within 13 reaches, thermologgers were deployed at 9 locations to record water temperatures, and fish populations were surveyed at 22 individual sites. Additionally, fish were tagged with Passive Integrated Transponder (PIT) tags, which allowed movement and growth information to be collected on individual fish. The movements of tagged fish were monitored with a combination of recapture events and stationary in-stream antennas, which detected tagged fish. Meadow Valley Wash within Condor Canyon was divided by a 12-meter (m) waterfall known as Delmue Falls. About 6,100 m of stream were surveyed downstream of the falls and about 2,200 m of stream were surveyed upstream of the falls. Although about three-quarters of the surveyed stream length was downstream of Delmue Falls, the highest densities and abundance of native fish were upstream of the falls. Big Spring spinedace and desert sucker populations were highest near the

  15. CREATION OF A GEOGRAPHIC INFORMATION SYSTEM TO IDENTIFY AT-RISK POPULATIONS IN NEW JERSEY AND NEW YORK FOR CONSUMPTION OF CONTAMINATED FISH AND SEAFOOD

    EPA Science Inventory

    Project Objective: To identify at-risk populations, particularly women of child bearing years and young children, for consumption of contaminated fish and seafood via the use of geographically and demographically defined seafood consumption patterns and fish/seafood contaminatio...

  16. Demographic Demise: The Declining Young Adult Population in New England

    ERIC Educational Resources Information Center

    Gittell, Ross

    2007-01-01

    Young adult workers provide businesses with the dynamic labor force and fresh ideas they need to innovate and grow. With their contributions to cultural, intellectual and social life, young adults also make New England a vibrant and interesting place to live. Young families support local schools and demand a strong educational system. Yet New…

  17. Factors and Mechanisms for Pharmacokinetic Differences between Pediatric Population and Adults

    PubMed Central

    Fernandez, Eva; Perez, Raul; Hernandez, Alfredo; Tejada, Pilar; Arteta, Marta; Ramos, Jose T.

    2011-01-01

    Many physiologic differences between children and adults may result in age-related changes in pharmacokinetics and pharmacodynamics. Factors such as gastric pH and emptying time, intestinal transit time, immaturity of secretion and activity of bile and pancreatic fluid among other factors determine the oral bioavailability of pediatric and adult populations. Anatomical, physiological and biochemical characteristics in children also affect the bioavailability of other routes of administration. Key factors explaining differences in drug distribution between the pediatric population and adults are membrane permeability, plasma protein binding and total body water. As far as drug metabolism is concerned, important differences have been found in the pediatric population compared with adults both for phase I and phase II metabolic enzymes. Immaturity of glomerular filtration, renal tubular secretion and tubular reabsorption at birth and their maturation determine the different excretion of drugs in the pediatric population compared to adults. PMID:24310425

  18. Population genomics of local adaptation versus speciation in coral reef fishes (Hypoplectrus spp, Serranidae).

    PubMed

    Picq, Sophie; McMillan, W Owen; Puebla, Oscar

    2016-04-01

    Are the population genomic patterns underlying local adaptation and the early stages of speciation similar? Addressing this question requires a system in which (i) local adaptation and the early stages of speciation can be clearly identified and distinguished, (ii) the amount of genetic divergence driven by the two processes is similar, and (iii) comparisons can be repeated both taxonomically (for local adaptation) and geographically (for speciation). Here, we report just such a situation in the hamlets (Hypoplectrus spp), brightly colored reef fishes from the wider Caribbean. Close to 100,000 SNPs genotyped in 126 individuals from three sympatric species sampled in three repeated populations provide genome-wide levels of divergence that are comparable among allopatric populations (F st estimate = 0.0042) and sympatric species (F st estimate = 0.0038). Population genetic, clustering, and phylogenetic analyses reveal very similar patterns for local adaptation and speciation, with a large fraction of the genome undifferentiated (F st estimate ≈ 0), a very small proportion of F st outlier loci (0.05-0.07%), and remarkably few repeated outliers (1-3). Nevertheless, different loci appear to be involved in the two processes in Hypoplectrus, with only 7% of the most differentiated SNPs and outliers shared between populations and species comparisons. In particular, a tropomyosin (Tpm4) and a previously identified hox (HoxCa) locus emerge as candidate loci (repeated outliers) for local adaptation and speciation, respectively. We conclude that marine populations may be locally adapted notwithstanding shallow levels of genetic divergence, and that from a population genomic perspective, this process does not appear to differ fundamentally from the early stages of speciation.

  19. Cognitive performance in older adults is inversely associated with fish consumption but not erythrocyte membrane n-3 fatty acids.

    PubMed

    Danthiir, Vanessa; Hosking, Diane; Burns, Nicholas R; Wilson, Carlene; Nettelbeck, Ted; Calvaresi, Eva; Clifton, Peter; Wittert, Gary A

    2014-03-01

    Higher n-3 (ω-3) polyunsaturated fatty acids (PUFAs) and fish intake may help maintain cognitive function in older age. However, evidence is inconsistent; few studies have examined the relation in cognitively healthy individuals across numerous cognitive domains, and none to our knowledge have considered lifetime fish intake. We examined associations between multiple domains of cognition and erythrocyte membrane n-3 PUFA proportions and historical and contemporary fish intake in 390 normal older adults, analyzing baseline data from the Older People, Omega-3, and Cognitive Health trial. We measured n-3 PUFA in erythrocyte membranes, and we assessed historical and contemporary fish intake by food-frequency questionnaires. We assessed cognitive performance on reasoning, working memory, short-term memory, retrieval fluency, perceptual speed, simple/choice reaction time, speed of memory-scanning, reasoning speed, inhibition, and psychomotor speed. Cognitive outcomes for each construct were factor scores from confirmatory factor analysis. Multiple linear regression models controlled for a number of potential confounding factors, including age, education, sex, apolipoprotein E-ε 4 allele, physical activity, smoking, alcohol intake, socioeconomic variables, and other health-related variables. Higher erythrocyte membrane eicosapaentonoic acid proportions predicted slower perceptual and reasoning speed in females, which was attenuated once current fish intake was controlled. No other associations were present between n-3 PUFA proportions and cognitive performance. Higher current fish consumption predicted worse performance on several cognitive speed constructs. Greater fish consumption in childhood predicted slower perceptual speed and simple/choice reaction time. We found no evidence to support the hypothesis that higher proportions of long-chain n-3 fatty acids or fish intake benefits cognitive performance in normal older adults.

  20. Adult survival and population growth rate in Colorado big brown bats (Eptesicus fuscus)

    USGS Publications Warehouse

    O'Shea, T.J.; Ellison, L.E.; Stanley, T.R.

    2011-01-01

    We studied adult survival and population growth at multiple maternity colonies of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado. We investigated hypotheses about survival using information-theoretic methods and mark-recapture analyses based on passive detection of adult females tagged with passive integrated transponders. We constructed a 3-stage life-history matrix model to estimate population growth rate (??) and assessed the relative importance of adult survival and other life-history parameters to population growth through elasticity and sensitivity analysis. Annual adult survival at 5 maternity colonies monitored from 2001 to 2005 was estimated at 0.79 (95% confidence interval [95% CI] = 0.77-0.82). Adult survival varied by year and roost, with low survival during an extreme drought year, a finding with negative implications for bat populations because of the likelihood of increasing drought in western North America due to global climate change. Adult survival during winter was higher than in summer, and mean life expectancies calculated from survival estimates were lower than maximum longevity records. We modeled adult survival with recruitment parameter estimates from the same population. The study population was growing (?? = 1.096; 95% CI = 1.057-1.135). Adult survival was the most important demographic parameter for population growth. Growth clearly had the highest elasticity to adult survival, followed by juvenile survival and adult fecundity (approximately equivalent in rank). Elasticity was lowest for fecundity of yearlings. The relative importances of the various life-history parameters for population growth rate are similar to those of large mammals. ?? 2011 American Society of Mammalogists.

  1. Effect of temperature-transfer on growth of laboratory populations of a South American annual fish Cynolebias bellottii.

    PubMed

    Liu, R K; Leung, B E; Walford, R L

    1975-09-01

    Previous observation had shown that annual fish living at 15 degrees C grow faster and live longer than those at 20 degrees C. We now demonstrate that when populations of these fish undergo reciprocal transfer between these two temperatures, their growth rates change to that of animals living at the temperature into which they have been transferred. These growth rates do not entirely correlate with the longevity patterns observed in annual fish subjected to temperature-transfer, nor to certain other observations of the relationships among growth, temperature and longevity as reported in the literature.

  2. Resilience and tipping points of an exploited fish population over six decades.

    PubMed

    Vasilakopoulos, Paraskevas; Marshall, C Tara

    2015-05-01

    Complex natural systems with eroded resilience, such as populations, ecosystems and socio-ecological systems, respond to small perturbations with abrupt, discontinuous state shifts, or critical transitions. Theory of critical transitions suggests that such systems exhibit fold bifurcations featuring folded response curves, tipping points and alternate attractors. However, there is little empirical evidence of fold bifurcations occurring in actual complex natural systems impacted by multiple stressors. Moreover, resilience of complex systems to change currently lacks clear operational measures with generic application. Here, we provide empirical evidence for the occurrence of a fold bifurcation in an exploited fish population and introduce a generic measure of ecological resilience based on the observed fold bifurcation attributes. We analyse the multivariate development of Barents Sea cod (Gadus morhua), which is currently the world's largest cod stock, over six decades (1949-2009), and identify a population state shift in 1981. By plotting a multivariate population index against a multivariate stressor index, the shift mechanism was revealed suggesting that the observed population shift was a nonlinear response to the combined effects of overfishing and climate change. Annual resilience values were estimated based on the position of each year in relation to the fitted attractors and assumed tipping points of the fold bifurcation. By interpolating the annual resilience values, a folded stability landscape was fit, which was shaped as predicted by theory. The resilience assessment suggested that the population may be close to another tipping point. This study illustrates how a multivariate analysis, supported by theory of critical transitions and accompanied by a quantitative resilience assessment, can clarify shift mechanisms in data-rich complex natural systems.

  3. Does mating behaviour affect connectivity in marine fishes? Comparative population genetics of two protogynous groupers (Family Serranidae).

    PubMed

    Portnoy, D S; Hollenbeck, C M; Renshaw, M A; Cummings, N J; Gold, J R

    2013-01-01

    Pelagic larval duration (PLD) has been hypothesized to be the primary predictor of connectivity in marine fishes; however, few studies have examined the effects that adult reproductive behaviour may have on realized dispersal. We assessed gene flow (connectivity) by documenting variation in microsatellites and mitochondrial DNA sequences in two protogynous species of groupers, the aggregate spawning red hind, Epinephelus guttatus, and the single-male, harem-spawning coney, Cephalopholis fulva, to ask whether reproductive strategy affects connectivity. Samples of both species were obtained from waters off three islands (Puerto Rico, St. Thomas and St. Croix) in the Caribbean Sea. Despite the notion that aggregate spawning of red hind may facilitate larval retention, stronger signals of population structure were detected in the harem-spawning coney. Heterogeneity and/or inferred barriers, based on microsatellites, involved St. Croix (red hind and coney) and the west coast of Puerto Rico (coney). Heterogeneity and/or inferred barriers, based on mitochondrial DNA, involved St. Croix (coney only). Genetic divergence in both species was stronger for microsatellites than for mitochondrial DNA, suggesting sex-biased dispersal in both species. Long-term migration rates, based on microsatellites, indicated asymmetric gene flow for both species in the same direction as mean surface currents in the region. Red hind had higher levels of variation in microsatellites and lower levels of variation in mitochondrial DNA. Long-term effective size and effective number of breeders were greater for red hind; estimates of θ(f) , a proxy for long-term effective female size, were the same in both species. Patterns of gene flow in both species appear to stem in part from shared aspects of larval and adult biology, local bathymetry and surface current patterns. Differences in connectivity and levels of genetic variation between the species, however, likely stem from differences in behaviour

  4. A phylogenetic analysis of egg size, clutch size, spawning mode, adult body size, and latitude in reef fishes

    NASA Astrophysics Data System (ADS)

    Kasimatis, Katja; Riginos, Cynthia

    2016-06-01

    Theoretical treatments of egg size in fishes suggest that constraints on reproductive output should create trade-offs between the size and number of eggs produced per spawn. For marine reef fishes, the observation of distinct reproductive care strategies (demersal guarding, egg scattering, and pelagic spawning) has additionally prompted speculation that these strategies reflect alternative fitness optima with selection on egg size differing by reproductive mode and perhaps latitude. Here, we aggregate data from 278 reef fish species and test whether clutch size, reproductive care, adult body size, and latitudinal bands (i.e., tropical, subtropical, and temperate) predict egg size, using a statistically unified framework that accounts for phylogenetic correlations among traits. We find no inverse relationship between species egg size and clutch size, but rather that egg size differs by reproductive mode (mean volume for demersal eggs = 1.22 mm3, scattered eggs = 0.18 mm3, pelagic eggs = 0.52 mm3) and that clutch size is strongly correlated with adult body size. Larger eggs were found in temperate species compared with tropical species in both demersal guarders and pelagic spawners, but this difference was not strong when accounting for phylogenetic correlations, suggesting that differences in species composition underlies regional differences in egg size. In summary, demersal guarders are generally small fishes with small clutch sizes that produce large eggs. Pelagic spawners and egg scatterers are variable in adult and clutch size. Although pelagic spawned eggs are variable in size, those of scatterers are consistently small.

  5. The impacts of mobile fishing gear on seafloor habitats in the gulf of maine (Northwest Atlantic): Implications for conservation of fish populations

    USGS Publications Warehouse

    Auster, P.J.; Malatesta, R.J.; Langton, R.W.; Watling, Les; Valentine, P.C.; Donaldson, C.L.S.; Langton, E.W.; Shepard, A.N.; Babb, Ivar G.

    1996-01-01

    Fishing gear alters seafloor habitats, but the extent of these alterations, and their effects, have not been quantified extensively in the northwest Atlantic. Understanding the extent of these impacts, and their effects on populations of living marine resources, is needed to properly manage current and future levels of fishing effort and fishing power. For example, the entire U.S. side of the Gulf of Maine was impacted annually by mobile fishing gear between 1984 and 1990, based on calculations of area swept by trawl and dredge gear. Georges Bank was impacted three to nearly four times annually during the same period. Studies at three sites in the Gulf of Maine (off Swans Island, Jeffreys Bank, and Stellwagen Bank) showed that mobile fishing gear altered the physical structure (=complexity) of benthic habitats. Complexity was reduced by direct removal of biogenic (e.g., sponges, hydrozoans, bryozoans, amphipod tubes, holothurians, shell aggregates) and sedimentary (e.g., sand waves, depressions) structures. Also, removal of organisms that create structures (e.g., crabs, scallops) indirectly reduced complexity. Reductions in habitat complexity may lead to increased predation on juveniles of harvested species and ultimately recruitment to the harvestable stock. Because of a lack of reference sites, where use of mobile fishing is prohibited, no empirical studies have yet been conducted on a scale that could demonstrate population level effects of habitat-management options. If marine fisheries management is to evolve toward an ecosystem or habitat management approach, experiments are required on the effects of habitat change, both anthropogenic and natural.

  6. The impacts of mobile fishing gear on seafloor habitats in the Gulf of Maine (Northwest Atlantic): implications for conservation of fish populations

    USGS Publications Warehouse

    Auster, Peter J.; Malatesta, Richard J.; Langton, Richard W.; Watting, Les; Valentine, Page C.; Donaldson, Carol Lee S.; Langton, Elizabeth W.; Shepard, Andrew N.; Babb, War G.

    1997-01-01

    Fishing gear alters seafloor habitats, but the extent of these alterations, and their effects, have not been quantified extensively in the northwest Atlantic. Understanding the extent of these impacts, and their effects on populations of living marine resources, is needed to properly manage current and future levels of fishing effort and fishing power. For example, the entire U.S. side of the Gulf of Maine was impacted annually by mobile fishing gear between 1984 and 1990, based on calculations of area swept by trawl and dredge gear. Georges Bank was imparted three to nearly four times annually during the same period. Studies at three sites in the Gulf of Maine (off Swans Island, Jeffreys Bank, and Stellwagen Bank) showed that mobile fishing gear altered the physical structure (=complexity) of benthic habitats. Complexity was reduced by direct removal of biogenic (e.g., sponges, hydrozoans, bryozoans, amphipod tubes, holothurians, shell aggregates) and‐ sedimentary (e.g., sand waves, depressions) structures. Also, removal of organisms that create.structures (e.g., crabs, scallops) indirectly reduced complexity. Reductions in habitat complexity may lead to increased predation on juveniles of harvested species and ultimately recruitment to the harvestable stock. Because of a lack of reference sites, where use of mobile fishing is prohibited, no empirical studies have yet been conducted on a scale that could demonstrate population level effects of habitat‐management options. If marine fisheries management is to evolve toward an ecosystem or habitat management approach, experiments are required on the effects of habitat change, both anthropogenic and natural.

  7. Regenerating Fish Optic Nerves and a Regeneration-Like Response in Injured Optic Nerves of Adult Rabbits

    NASA Astrophysics Data System (ADS)

    Schwartz, M.; Belkin, M.; Harel, A.; Solomon, A.; Lavie, V.; Hadani, M.; Rachailovich, I.; Stein-Izsak, C.

    1985-05-01

    Regeneration of fish optic nerve (representing regenerative central nervous system) was accompanied by increased activity of regeneration-triggering factors produced by nonneuronal cells. A graft of regenerating fish optic nerve, or a ``wrap-around'' implant containing medium conditioned by it, induced a response associated with regeneration in injured optic nerves of adult rabbits (representing a nonregenerative central nervous system). This response was manifested by an increase of general protein synthesis and of selective polypeptides in the retinas and by the ability of the retina to sprout in culture.

  8. Projected risk of population declines for native fish species in the Upper Mississippi River

    USGS Publications Warehouse

    Crimmins, S.M.; Boma, P.; Thogmartin, W.E.

    2015-01-01

    Conservationists are in need of objective metrics for prioritizing the management of habitats. For individual species, the threat of extinction is often used to prioritize what species are in need of conservation action. Using long-term monitoring data, we applied a Bayesian diffusion approximation to estimate quasi-extinction risk for 54 native fish species within six commercial navigation reaches along a 1350-km gradient of the upper Mississippi River system. We found a strong negative linear relationship between quasi-extinction risk and distance upstream. For some species, quasi-extinction estimates ranged from nearly zero in some reaches to one in others, suggesting substantial variability in threats facing individual river reaches. We found no evidence that species traits affected quasi-extinction risk across the entire system. Our results indicate that fishes within the upper Mississippi River system face localized threats that vary across river impact gradients. This suggests that conservation actions should be focused on local habitat scales but should also consider the additive effects on downstream conditions. We also emphasize the need for identification of proximate mechanisms behind observed and predicted population declines, as conservation actions will require mitigation of such mechanisms. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  9. Oceanography and life history predict contrasting genetic population structure in two Antarctic fish species

    PubMed Central

    Young, Emma F; Belchier, Mark; Hauser, Lorenz; Horsburgh, Gavin J; Meredith, Michael P; Murphy, Eugene J; Pascoal, Sonia; Rock, Jennifer; Tysklind, Niklas; Carvalho, Gary R

    2015-01-01

    Understanding the key drivers of population connectivity in the marine environment is essential for the effective management of natural resources. Although several different approaches to evaluating connectivity have been used, they are rarely integrated quantitatively. Here, we use a ‘seascape genetics’ approach, by combining oceanographic modelling and microsatellite analyses, to understand the dominant influences on the population genetic structure of two Antarctic fishes with contrasting life histories, Champsocephalus gunnari and Notothenia rossii. The close accord between the model projections and empirical genetic structure demonstrated that passive dispersal during the planktonic early life stages is the dominant influence on patterns and extent of genetic structuring in both species. The shorter planktonic phase of C. gunnari restricts direct transport of larvae between distant populations, leading to stronger regional differentiation. By contrast, geographic distance did not affect differentiation in N. rossii, whose longer larval period promotes long-distance dispersal. Interannual variability in oceanographic flows strongly influenced the projected genetic structure, suggesting that shifts in circulation patterns due to climate change are likely to impact future genetic connectivity and opportunities for local adaptation, resilience and recovery from perturbations. Further development of realistic climate models is required to fully assess such potential impacts. PMID:26029262

  10. Potential population and assemblage influences of non-native trout on native nongame fish in Nebraska headwater streams

    USGS Publications Warehouse

    Turek, Kelly C.; Pegg, Mark A.; Pope, Kevin L.; Schainost, Steve

    2014-01-01

    Non-native trout are currently stocked to support recreational fisheries in headwater streams throughout Nebraska. The influence of non-native trout introductions on native fish populations and their role in structuring fish assemblages in these systems is unknown. The objectives of this study were to determine (i) if the size structure or relative abundance of native fish differs in the presence and absence of non-native trout, (ii) if native fish-assemblage structure differs in the presence and absence of non-native trout and (iii) if native fish-assemblage structure differs across a gradient in abundances of non-native trout. Longnose dace Rhinichthys cataractae were larger in the presence of brown trout Salmo trutta and smaller in the presence of rainbow trout Oncorhynchus mykiss compared to sites without trout. There was also a greater proportion of larger white suckers Catostomus commersonii in the presence of brown trout. Creek chub Semotilus atromaculatus and fathead minnow Pimephales promelas size structures were similar in the presence and absence of trout. Relative abundances of longnose dace, white sucker, creek chub and fathead minnow were similar in the presence and absence of trout, but there was greater distinction in native fish-assemblage structure between sites with trout compared to sites without trout as trout abundances increased. These results suggest increased risk to native fish assemblages in sites with high abundances of trout. However, more research is needed to determine the role of non-native trout in structuring native fish assemblages in streams, and the mechanisms through which introduced trout may influence native fish populations.

  11. Evaluation of marine subareas of Europe using life history parameters and trophic levels of selected fish populations.

    PubMed

    Jayasinghe, R P Prabath K; Amarasinghe, Upali S; Newton, Alice

    2015-12-01

    European marine waters include four regional seas that provide valuable ecosystem services to humans, including fish and other seafood. However, these marine environments are threatened by pressures from multiple anthropogenic activities and climate change. The European Marine Strategy Framework Directive (MSFD) was adopted in 2008 to achieve good environmental status (GEnS) in European Seas by year 2020, using an Ecosystem Approach. GEnS is to be assessed using 11 descriptors and up to 56 indicators. In the present analysis two descriptors namely "commercially exploited fish and shellfish populations" and "food webs" were used to evaluate the status of subareas of FAO 27 area. Data on life history parameters, trophic levels and fisheries related data of cod, haddock, saithe, herring, plaice, whiting, hake and sprat were obtained from the FishBase online database and advisory reports of International Council for the Exploration of the Sea (ICES). Subareas inhabited by r and K strategists were identified using interrelationships of life history parameters of commercially important fish stocks. Mean trophic level (MTL) of fish community each subarea was calculated and subareas with species of high and low trophic level were identified. The Fish in Balance (FiB) index was computed for each subarea and recent trends of FiB indices were analysed. The overall environmental status of each subarea was evaluated considering life history trends, MTL and FiB Index. The analysis showed that subareas I, II, V, VIII and IX were assessed as "good" whereas subareas III, IV, VI and VII were assessed as "poor". The subareas assessed as "good" were subject to lower environmental pressures, (less fishing pressure, less eutrophication and more water circulation), while the areas with "poor" environment experienced excessive fishing pressure, eutrophication and disturbed seabed. The evaluation was based on two qualitative descriptors ("commercially exploited fish and shellfish

  12. Use of population viability analysis to evaluate CITES trade-management options for threatened marine fishes.

    PubMed

    Curtis, Janelle M R; Vincent, Amanda C J

    2008-10-01

    Achieving multiple conservation objectives can be challenging, particularly under high uncertainty. Having agreed to limit seahorse (Hippocampus) exports to sustainable levels, signatories to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) were offered the option of a single 10-cm minimum size limit (MSL) as an interim management measure for all Hippocampus species (> or =34). Although diverse stakeholders supported the recommended MSL, its biological and socioeconomic implications were not assessed quantitatively. We combined population viability analysis, model sensitivity analysis, and economic information to evaluate the trade-off between conservation threat to and long-term cumulative income from these exploited marine fishes of high conservation concern. We used the European long-snouted seahorse (Hippocampus guttulatus) as a representative species to compare the performance of MSLs set at alternative biological reference points. Our sensitivity analyses showed that in most of our scenarios, setting the MSL just above size at maturity (9.7 cm in H. guttulatus) would not prevent exploited populations from becoming listed as vulnerable. By contrast, the relative risk of decline and extinction were almost halved--at a cost of only a 5.6% reduction in long-term catches--by increasing the MSL to the size reached after at least one full reproductive season. On the basis of our analysis, a precautionary increase in the MSL could be compatible with sustaining fishers' livelihoods and international trade. Such management tactics that aid species conservation and have minimal effects on long term catch trends may help bolster the case for CITES trade management of other valuable marine fishes.

  13. Power to Detect Trends in Missouri River Fish Populations within the Habitat Assessment Monitoring Program

    USGS Publications Warehouse

    Bryan, Janice L.; Wildhaber, Mark L.; Gladish, Dan W.

    2010-01-01

    As with all large rivers in the United States, the Missouri River has been altered, with approximately one-third of the mainstem length impounded and one-third channelized. These physical alterations to the environment have affected the fish populations, but studies examining the effects of alterations have been localized and for short periods of time, thereby preventing generalization. In response to the U.S. Fish and Wildlife Service Biological Opinion, the U.S. Army Corps of Engineers (USACE) initiated monitoring of habitat improvements of the Missouri River in 2005. The goal of the Habitat Assessment Monitoring Program (HAMP) is to provide information on the response of target fish species to the USACE habitat creation on the Lower Missouri River. To determine the statistical power of the HAMP and in cooperation with USACE, a power analysis was conducted using a normal linear mixed model with variance component estimates based on the first complete year of data. At a level of 20/16 (20 bends with 16 subsamples in each bend), at least one species/month/gear model has the power to determine differences between treated and untreated bends. The trammel net in September had the most species models with adequate power at the 20/16 level and overall, the trammel net had the most species/month models with adequate power at the 20/16 level. However, using only one gear or gear/month combination would eliminate other species of interest, such as three chub species (Macrhybopsis meeki, Macrhybopsis aestivalis, and Macrhybopsis gelida), sand shiners (Notropis stramineus), pallid sturgeon (Scaphirhynchus albus), and juvenile sauger (Sander canadensis). Since gear types are selective in their species efficiency, the strength of the HAMP approach is using multiple gears that have statistical power to differentiate habitat treatment differences in different fish species within the Missouri River. As is often the case with sampling rare species like the pallid sturgeon, the

  14. Prevalence of Chronic Medical Conditions in Adults with Mental Retardation: Comparison with the General Population.

    ERIC Educational Resources Information Center

    Kapell, Deborah; Nightingale, Beryle; Rodriguez, Ana; Lee, Joseph H.; Zigman, Warren B.; Schupf, Nicole

    1998-01-01

    A study interviewed caregivers and reviewed medical records of 278 adults with mental retardation with and without Down syndrome. The adults with mental retardation had age-related disorders comparable to those in the general population, but there was an increased frequency of thyroid disorders, nonischemic heart disorders, and sensory impairment.…

  15. The National Blueprint for Promoting Physical Activity in the Mid-Life and Older Adult Population

    ERIC Educational Resources Information Center

    Chodzko-Zajko, Wojtek; Sheppard, Lisa; Senior, Jane; Park, Chae-Hee; Mockenhaupt, Robin; Bazzarre, Terry

    2005-01-01

    The National Blueprint: Increasing Physical Activity Among Adults Age 50 and Older was designed to develop a national strategy for the promotion of physically active lifestyles among the mid-life and older adult population. The Blueprint identifies barriers to physical activity in the areas of research, home and community programs, medical…

  16. Cardiorespiratory performance and blood chemistry during swimming and recovery in three populations of elite swimmers: Adult sockeye salmon.

    PubMed

    Eliason, Erika J; Clark, Timothy D; Hinch, Scott G; Farrell, Anthony P

    2013-10-01

    Every year, millions of adult sockeye salmon (Oncorhynchus nerka) perform an arduous, once-in-a-lifetime migration up the Fraser River (BC, Canada) to return to their natal stream to spawn. The changes in heart rate, stroke volume, and arterio-venous oxygen extraction (i.e., factors determining rates of oxygen delivery to the tissues by the cardiovascular system) have never been directly and simultaneously measured along with whole animal oxygen uptake in a maximally swimming fish. Here, such measurements were made using three sockeye salmon populations (Early Stuart, Chilko and Quesnel), which each performed two consecutive critical swimming speed (Ucrit) challenges to provide a comprehensive quantification of cardiovascular physiology, oxygen status and blood chemistry associated with swimming and recovery. Swim performance, oxygen uptake, cardiac output, heart rate and stroke volume did not significantly vary at rest, during swimming or during recovery between populations or sexes. Despite incomplete metabolic recovery between swim challenges, all fish repeated their swim performance and similar quantitative changes in the cardiorespiratory variables were observed for each swim challenge. The high maximum cardiorespiratory performance and excellent repeat swim performance are clearly beneficial in allowing the salmon to maintain steady ground speeds and reach the distant spawning grounds in a timely manner.

  17. Low levels of genetic differentiation among populations of the freshwater fish Hypseleotris compressa (Gobiidae: Eleotridinae): implications for its biology, population connectivity and history.

    PubMed

    McGlashan, D J; Hughes, J M

    2001-02-01

    The isolating nature of freshwater systems may lead to expectations of substantial genetic subdivision among populations of obligate freshwater species. We examined the genetic structure of populations of the freshwater fish Hypseleotris compressa (Gobiidae) using allozyme and mtDNA markers. Fifteen east coast Queensland populations and one Northern Territory population were sampled to examine levels of differentiation within and between drainages at near, medium and broad scales. Initial allozyme data suggested high levels of gene flow and connectivity among populations at broad spatial scales. However there was no significant relationship between geographical distance and gene flow among east coast populations which may indicate, among other possibilities, that these populations are not at equilibrium between gene flow and genetic drift. Analyses of a 567-bp fragment of the ATPase6 mtDNA gene revealed a star-shaped phylogeny, with many singleton, recently derived haplotypes. Tajima's test of neutrality was significantly negative. The allozyme and mtDNA data may be indicative of an historical demographic change that was reflected in the nonequilibrium pattern exhibited by contemporary populations. As estimating current levels of gene flow would violate basic assumptions of underlying models, approximations were not made. Nevertheless, patterns of genetic variation among populations of H. compressa do not match traditional expectations for a freshwater fish, and it would appear that there has been at least historical connectivity between populations now inhabiting different drainages.

  18. Urinary arsenic levels in the French adult population: the French National Nutrition and Health Study, 2006-2007.

    PubMed

    Saoudi, Abdessattar; Zeghnoun, Abdelkrim; Bidondo, Marie-Laure; Garnier, Robert; Cirimele, Vincent; Persoons, Renaud; Fréry, Nadine

    2012-09-01

    The French Nutrition and Health Survey (ENNS) was conducted to describe dietary intakes, nutritional status, physical activity, and levels of various biomarkers for environmental chemicals (heavy metals and pesticides) in the French population (adults aged 18-74 years and children aged 3-17 years living in continental France in 2006-2007). The aim of this paper was to describe the distributions of total arsenic and the sum of iAs+MMA+DMA in the general adult population, and to present their main risk factors. In the arsenic study, 1500 and 1515 adults (requested to avoid seafood intake in the previous 3 days preceding urine collection) were included respectively for the analysis of the sum of inorganic arsenic (iAs) and its two metabolites, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), and for the total arsenic. Results were presented as geometric means and selected percentiles of urinary arsenic concentrations (μg/L) and creatinine-adjusted urinary arsenic (μg/g of creatinine) for total arsenic, and the sum of inorganic arsenic and metabolites (iAs+MMA+DMA). The geometric mean concentration of the sum of iAs+MMA+DMA in the adult population living in France was 3.34 μg/g of creatinine [3.23-3.45] (3.75 μg/L [3.61-3.90]) with a 95th percentile of 8.9 μg/g of creatinine (10.68 μg/L). The geometric mean concentration of total arsenic was 11.96 μg/g of creatinine [11.41-12.53] (13.42 μg/L [12.77-14.09]) with a 95th percentile of 61.29 μg/g of creatinine (72.75 μg/L). Urinary concentrations of total arsenic and iAS+MMA+DMA were influenced by sociodemographic and economic factors, and by risk factors such as consumption of seafood products and of wine. In our study, covariate-adjusted geometric means demonstrated several slight differences, due to consumption of fish, shellfish/crustaceans or wine. This study provides the first reference value for arsenic in a representative sample of the French population not particularly exposed to high levels

  19. Deep sexual dimorphism in adult medaka fish liver highlighted by multi-omic approach

    PubMed Central

    Qiao, Qin; Le Manach, Séverine; Sotton, Benoit; Huet, Hélène; Duvernois-Berthet, Evelyne; Paris, Alain; Duval, Charlotte; Ponger, Loïc; Marie, Arul; Blond, Alain; Mathéron, Lucrèce; Vinh, Joelle; Bolbach, Gérard; Djediat, Chakib; Bernard, Cécile; Edery, Marc; Marie, Benjamin

    2016-01-01

    Sexual dimorphism describes the features that discriminate between the two sexes at various biological levels. Especially, during the reproductive phase, the liver is one of the most sexually dimorphic organs, because of different metabolic demands between the two sexes. The liver is a key organ that plays fundamental roles in various physiological processes, including digestion, energetic metabolism, xenobiotic detoxification, biosynthesis of serum proteins, and also in endocrine or immune response. The sex-dimorphism of the liver is particularly obvious in oviparous animals, as the female liver is the main organ for the synthesis of oocyte constituents. In this work, we are interested in identifying molecular sexual dimorphism in the liver of adult medaka fish and their sex-variation in response to hepatotoxic exposures. By developing an integrative approach combining histology and different high-throughput omic investigations (metabolomics, proteomics and transcriptomics), we were able to globally depict the strong sexual dimorphism that concerns various cellular and molecular processes of hepatocytes comprising protein synthesis, amino acid, lipid and polysaccharide metabolism, along with steroidogenesis and detoxification. The results of this work imply noticeable repercussions on the biology of oviparous organisms environmentally exposed to chemical or toxin issues. PMID:27561897

  20. Metformin Exposure at Environmentally Relevant Concentrations Causes Potential Endocrine Disruption in Adult Male Fish

    PubMed Central

    Niemuth, Nicholas J; Jordan, Renee; Crago, Jordan; Blanksma, Chad; Johnson, Rodney; Klaper, Rebecca D

    2015-01-01

    Pharmaceuticals and personal care products (PPCPs) are emerging contaminants that have been found ubiquitously in wastewater and surface waters around the world. A major source of these compounds is incomplete metabolism in humans and subsequent excretion in human waste, resulting in discharge into surface waters by wastewater treatment plant (WWTP) effluent. One pharmaceutical found in particularly high abundance in recent WWTP effluent and surface water studies is metformin, one of the world's most widely prescribed antidiabetic drugs. Interactions between insulin signaling and steroidogenesis suggest potential endocrine-disrupting effects of metformin found in the aquatic environment. Adult fathead minnows (Pimephales promelas) were chronically exposed to metformin for 4 wk, at 40 µg/L, a level similar to the average found in WWTP effluent in Milwaukee, Wisconsin, USA. Genetic endpoints related to metabolism and endocrine function as well as reproduction-related endpoints were examined. Metformin treatment induced significant up-regulation of messenger ribonucleic acid (mRNA) encoding the egg-protein vitellogenin in male fish, an indication of endocrine disruption. The present study, the first to study the effects of environmentally relevant metformin exposure in fathead minnows, demonstrates the need for further study of the endocrine-disrupting effects of metformin in aquatic organisms. Environ Toxicol Chem 2014;9999:1–6. © 2014 The Authors. Published by Wiley Periodicals, Inc. on behalf of SETAC. PMID:25358780

  1. Metformin exposure at environmentally relevant concentrations causes potential endocrine disruption in adult male fish.

    PubMed

    Niemuth, Nicholas J; Jordan, Renee; Crago, Jordan; Blanksma, Chad; Johnson, Rodney; Klaper, Rebecca D

    2015-02-01

    Pharmaceuticals and personal care products (PPCPs) are emerging contaminants that have been found ubiquitously in wastewater and surface waters around the world. A major source of these compounds is incomplete metabolism in humans and subsequent excretion in human waste, resulting in discharge into surface waters by wastewater treatment plant (WWTP) effluent. One pharmaceutical found in particularly high abundance in recent WWTP effluent and surface water studies is metformin, one of the world's most widely prescribed antidiabetic drugs. Interactions between insulin signaling and steroidogenesis suggest potential endocrine-disrupting effects of metformin found in the aquatic environment. Adult fathead minnows (Pimephales promelas) were chronically exposed to metformin for 4 wk, at 40 µg/L, a level similar to the average found in WWTP effluent in Milwaukee, Wisconsin, USA. Genetic endpoints related to metabolism and endocrine function as well as reproduction-related endpoints were examined. Metformin treatment induced significant up-regulation of messenger ribonucleic acid (mRNA) encoding the egg-protein vitellogenin in male fish, an indication of endocrine disruption. The present study, the first to study the effects of environmentally relevant metformin exposure in fathead minnows, demonstrates the need for further study of the endocrine-disrupting effects of metformin in aquatic organisms.

  2. Deep sexual dimorphism in adult medaka fish liver highlighted by multi-omic approach.

    PubMed

    Qiao, Qin; Le Manach, Séverine; Sotton, Benoit; Huet, Hélène; Duvernois-Berthet, Evelyne; Paris, Alain; Duval, Charlotte; Ponger, Loïc; Marie, Arul; Blond, Alain; Mathéron, Lucrèce; Vinh, Joelle; Bolbach, Gérard; Djediat, Chakib; Bernard, Cécile; Edery, Marc; Marie, Benjamin

    2016-08-26

    Sexual dimorphism describes the features that discriminate between the two sexes at various biological levels. Especially, during the reproductive phase, the liver is one of the most sexually dimorphic organs, because of different metabolic demands between the two sexes. The liver is a key organ that plays fundamental roles in various physiological processes, including digestion, energetic metabolism, xenobiotic detoxification, biosynthesis of serum proteins, and also in endocrine or immune response. The sex-dimorphism of the liver is particularly obvious in oviparous animals, as the female liver is the main organ for the synthesis of oocyte constituents. In this work, we are interested in identifying molecular sexual dimorphism in the liver of adult medaka fish and their sex-variation in response to hepatotoxic exposures. By developing an integrative approach combining histology and different high-throughput omic investigations (metabolomics, proteomics and transcriptomics), we were able to globally depict the strong sexual dimorphism that concerns various cellular and molecular processes of hepatocytes comprising protein synthesis, amino acid, lipid and polysaccharide metabolism, along with steroidogenesis and detoxification. The results of this work imply noticeable repercussions on the biology of oviparous organisms environmentally exposed to chemical or toxin issues.

  3. Body Size and Geographic Range Do Not Explain Long Term Variation in Fish Populations: A Bayesian Phylogenetic Approach to Testing Assembly Processes in Stream Fish Assemblages

    PubMed Central

    Jacquemin, Stephen J.; Doll, Jason C.

    2014-01-01

    We combine evolutionary biology and community ecology to test whether two species traits, body size and geographic range, explain long term variation in local scale freshwater stream fish assemblages. Body size and geographic range are expected to influence several aspects of fish ecology, via relationships with niche breadth, dispersal, and abundance. These traits are expected to scale inversely with niche breadth or current abundance, and to scale directly with dispersal potential. However, their utility to explain long term temporal patterns in local scale abundance is not known. Comparative methods employing an existing molecular phylogeny were used to incorporate evolutionary relatedness in a test for covariation of body size and geographic range with long term (1983 – 2010) local scale population variation of fishes in West Fork White River (Indiana, USA). The Bayesian model incorporating phylogenetic uncertainty and correlated predictors indicated that neither body size nor geographic range explained significant variation in population fluctuations over a 28 year period. Phylogenetic signal data indicated that body size and geographic range were less similar among taxa than expected if trait evolution followed a purely random walk. We interpret this as evidence that local scale population variation may be influenced less by species-level traits such as body size or geographic range, and instead may be influenced more strongly by a taxon’s local scale habitat and biotic assemblages. PMID:24691075

  4. Visual Function and Visual Acuity in an Urban Adult Population.

    ERIC Educational Resources Information Center

    Katz, J.; Tielsch, J. M.

    1996-01-01

    A survey of 6,850 adults age 40 or over concerning the effects of poor vision found that difficulties with reading or other near-vision activities were the most common complaint. One-fourth reported limitations in activities because of poor vision. Factors associated with loss of visual function were general health status, educational level, and…

  5. Diverse juvenile life-history behaviours contribute to the spawning stock of an anadromous fish population

    USGS Publications Warehouse

    Walsworth, Timothy E.; Schindler, Daniel E.; Griffiths, Jennifer R.; Zimmerman, Christian E.

    2015-01-01

    Habitat quality often varies substantially across space and time, producing a shifting mosaic of growth and mortality trade-offs across watersheds. Traditional studies of juvenile habitat use have emphasised the evolution of single optimal strategies that maximise recruitment to adulthood and eventual fitness. However, linking the distribution of individual behaviours that contribute to recruitment at the population level has been elusive, particularly for highly fecund aquatic organisms. We examined juvenile habitat use within a population of sockeye salmon (Oncorhynchus nerka) that spawn in a watershed consisting of two interconnected lakes and a marine lagoon. Otolith microchemical analysis revealed that the productive headwater lake accounted for about half of juvenile growth for those individuals surviving to spawn in a single river in the upper watershed. However, 47% of adults had achieved more than half of their juvenile growth in the downstream less productive lake, and 3% of individuals migrated to the estuarine environment during their first summer and returned to freshwater to overwinter before migrating back to sea. These results describe a diversity of viable habitat-use strategies by juvenile sockeye salmon that may buffer the population against poor conditions in any single rearing environment, reduce density-dependent mortality and have implications for the designation of critical habitat for conservation purposes. A network of accessible alternative habitats providing trade-offs in growth and survival may be important for long-term viability of populations.

  6. Mercury (Hg) in fish consumed by the local population of the Jaguaribe River lower basin, Northeast Brazil.

    PubMed

    Costa, B G B; Lacerda, L D

    2014-12-01

    The knowledge of Hg concentrations in fish is of considerable interest since these organisms are a major source of protein to coastal human populations and fishing communities. The main source of human exposure to Hg contamination occurs through the consumption of fish. In this paper, we compare Hg concentration in 13 fish species from Jaguaribe River lower basin and an adjacent coastal region in the northeastern coast of Brazil. We sampled fish from three stretches of the river: fluvial, estuarine, and marine regions. We tested the hypothesis that Hg concentration in muscle tissue vary according to species, location, and trophic level. Significant differences were observed among species and trophic level, but these could not be observed among the regions studied. As expected, the highest concentrations were observed in carnivorous fish (5.6-107.5; 26.9 ± 18.8 ng g(-1)). Hg concentrations observed in this study are similar to those observed in regions of low environmental contamination. We estimated Hg intake to vary between 0.02 and 0.22 ng Hg kg body weight(-1) week(-1), for the average body weight of 56.7 kg, which was considered as low exposure and therefore, a low risk to consumers of fish from the regions studied.

  7. Population correlates of circulating mercury levels in Korean adults: the Korea National Health and Nutrition Examination Survey IV

    PubMed Central

    2014-01-01

    Background Prior studies focused on bioaccumulation of mercury (Hg) and on large, long-lived fish species as the major environmental source of Hg, but little is known about consumption of small-sized fish or about non-dietary determinants of circulating Hg levels. The purpose of this study was to evaluate whole blood mercury concentration (WBHg) and its major dietary and non-dietary correlates in Korean adults. Methods We analyzed cross-sectional data from 3,972 (male = 1,994; female = 1,978) participants who completed the Korean National Health and Nutrition Examination Survey IV, 2008 to 2009. Relevant factors included diet, geographic location of residence, demographics, and lifestyle. WBHg concentration was measured using cold-vapor atomic absorption spectrometry. Multivariable linear models assessed independent correlates of dietary and non-dietary factors for WBHg levels. Results Median levels of WBHg were 5.1 μg/L in men and 3.7 μg/L in women. Higher levels of fish/shellfish intake were associated with higher levels of WBHg. Higher consumption of small-sized fish was linked to higher levels of WBHg. Non-dietary predictors of higher WBHg were being male, greater alcohol consumption, higher income and education, overweight/obesity, increasing age, and living in the southeast region. Conclusions Both dietary and non-dietary factors were associated with WBHg levels in the Korean population. There is significant geographic variation in WBHg levels; residents living in the mid-south have higher WBHg levels. We speculate that uncontrolled geographic characteristics, such as local soil/water content and specific dietary habits are involved. PMID:24884916

  8. Understanding the determinate-indeterminate fecundity dichotomy in fish populations using a temperature dependent oocyte growth model

    NASA Astrophysics Data System (ADS)

    Ganias, Kostas; Lowerre-Barbieri, Susan K.; Cooper, Wade

    2015-02-01

    The fecundity type (determinate vs. indeterminate) is still uncertain for many commercially important fish populations affecting accuracy in fecundity estimations and hindering the selection of appropriate egg production methods for stock assessment purposes. It is broadly considered that boreal fish populations living in colder habitats are determinate spawners whilst populations residing in warmer habitats tend to be indeterminate spawners. In the present study we modelled the determinate-indeterminate fecundity type in batch spawning fishes, i.e. fish that spawn several batches of eggs per spawning season, based on the relationship between oocyte growth period and the duration of the spawning period considering that both variables can be affected by water temperature and latitudinal distributions. Individual based models (IBMs) were developed to explore how the interaction of these variables can result in a series of patterns along the continuum from extreme determinacy, i.e. annual fecundity being recruited long before the onset of the spawning period, to indeterminacy. Model simulations showed that fish stocks with oocyte growth periods longer than the spawning period are predicted to exhibit determinate fecundity which provides a fair justification for why cold water species with slow oocyte growth and limited spawning periods are determinate spawners and vice versa.

  9. Well-Being in an Adult Swedish Population

    ERIC Educational Resources Information Center

    Hansson, Anna; Hilleras, Pernilla; Forsell, Yvonne

    2005-01-01

    Objectives: The aim of this study was to see if earlier findings about factors associated with well-being could be replicated in a large population-based sample in Sweden. To the best of our knowledge, no research on well-being has been conducted on such a large population in a country, which by most standards is regarded as one of the most…

  10. Dissociative Symptoms and Mother's Marital Status in Young Adult Population

    PubMed Central

    Bob, Petr; Selesova, Petra; Raboch, Jiri; Kukla, Lubomir

    2015-01-01

    Abstract Current findings suggest that mother's marital status indicating father's absence or conflicting relationship to father may be specifically related to dissociation and other stress-related symptoms. We have assessed relationships of mother's marital status, dissociative symptoms, and other psychopathological manifestations in a sample of 19 years’ old young adults (N = 364) participating in European longitudinal study (European Longitudinal Study of Parenthood and Childhood). The results show clinically significant manifestations of dissociative symptoms in young adult men whose mothers were fatherless and in women whose mothers were re-married. Other psychopathological symptoms did not reach clinically significant manifestations. The results suggest that significant factor related to high level of dissociative symptoms in men growing in fatherless families might be linked with disturbed and conflicting attachment to a father's figure and pathological dependent attachment to mother. In women dissociative symptoms likely are linked to conflicting relationship between mother and daughter associated with stepfather’ presence in the family. PMID:25590849

  11. Population genomic tests of models of adaptive radiation in Lake Victoria region cichlid fish.

    PubMed

    Bezault, Etienne; Mwaiko, Salome; Seehausen, Ole

    2011-12-01

    Adaptive radiation is usually thought to be associated with speciation, but the evolution of intraspecific polymorphisms without speciation is also possible. The radiation of cichlid fish in Lake Victoria (LV) is perhaps the most impressive example of a recent rapid adaptive radiation, with 600+ very young species. Key questions about its origin remain poorly characterized, such as the importance of speciation versus polymorphism, whether species persist on evolutionary time scales, and if speciation happens more commonly in small isolated or in large connected populations. We used 320 individuals from 105 putative species from Lakes Victoria, Edward, Kivu, Albert, Nabugabo and Saka, in a radiation-wide amplified fragment length polymorphism (AFLP) genome scan to address some of these questions. We demonstrate pervasive signatures of speciation supporting the classical model of adaptive radiation associated with speciation. A positive relationship between the age of lakes and the average genomic differentiation of their species, and a significant fraction of molecular variance explained by above-species level taxonomy suggest the persistence of species on evolutionary time scales, with radiation through sequential speciation rather than a single starburst. Finally the large gene diversity retained from colonization to individual species in every radiation suggests large effective population sizes and makes speciation in small geographical isolates unlikely.

  12. Diagnostic methodology is critical for accurately determining the prevalence of ichthyophonus infections in wild fish populations

    USGS Publications Warehouse

    Kocan, R.; Dolan, H.; Hershberger, P.

    2011-01-01

    Several different techniques have been employed to detect and identify Ichthyophonus spp. in infected fish hosts; these include macroscopic observation, microscopic examination of tissue squashes, histological evaluation, in vitro culture, and molecular techniques. Examination of the peer-reviewed literature revealed that when more than 1 diagnostic method is used, they often result in significantly different results; for example, when in vitro culture was used to identify infected trout in an experimentally exposed population, 98.7% of infected trout were detected, but when standard histology was used to confirm known infected tissues from wild salmon, it detected ~50% of low-intensity infections and ~85% of high-intensity infections. Other studies on different species reported similar differences. When we examined a possible mechanism to explain the disparity between different diagnostic techniques, we observed non-random distribution of the parasite in 3-dimensionally visualized tissue sections from infected hosts, thus providing a possible explanation for the different sensitivities of commonly used diagnostic techniques. Based on experimental evidence and a review of the peer-reviewed literature, we have concluded that in vitro culture is currently the most accurate diagnostic technique for determining infection prevalence of Ichthyophonus, particularly when the exposure history of the population is not known.

  13. Effects of crossovers between homeologs on inheritance and population genomics in polyploid-derived salmonid fishes.

    PubMed

    Allendorf, Fred W; Bassham, Susan; Cresko, William A; Limborg, Morten T; Seeb, Lisa W; Seeb, James E

    2015-01-01

    A whole genome duplication occurred in the ancestor of all salmonid fishes some 50-100 million years ago. Early inheritance studies with allozymes indicated that loci in the salmonid genome are inherited disomically in females. However, some pairs of duplicated loci showed patterns of inheritance in males indicating pairing and recombination between homeologous chromosomes. Nearly 20% of loci in the salmonid genome are duplicated and share the same alleles (isoloci), apparently due to homeologous recombination. Half-tetrad analysis revealed that isoloci tend to be telomeric. These results suggested that residual tetrasomic inheritance of isoloci results from homeologous recombination near chromosome ends and that continued disomic inheritance resulted from homologous pairing of centromeric regions. Many current genetic maps of salmonids are based on single nucleotide polymorphisms and microsatellites that are no longer duplicated. Therefore, long sections of chromosomes on these maps are poorly represented, especially telomeric regions. In addition, preferential multivalent pairing of homeologs from the same species in F1 hybrids results in an excess of nonparental gametes (so-called pseudolinkage). We consider how not including duplicated loci has affected our understanding of population and evolutionary genetics of salmonids, and we discuss how incorporating these loci will benefit our understanding of population genomics.

  14. COLLAPSE OF A FISH POPULATION FOLLOWING EXPOSURE TO A SYNTHETIC ESTROGEN

    EPA Science Inventory

    Municipal wastewaters are a complex mixture containing estrogens and estrogen mimics that are known to affect the reproductive health of wild fishes. Male fishes downstream of some wastewater outfalls produce vitellogenin (VTG) (a protein normally synthesized by females during oo...

  15. Grammatical Class Effects Across Impaired Child and Adult Populations

    PubMed Central

    Kambanaros, Maria; Grohmann, Kleanthes K.

    2015-01-01

    The aims of this study are to compare quantitative and qualitative differences for noun/verb retrieval across language-impaired groups, examine naming errors with reference to psycholinguistic models of word processing, and shed light on the nature of the naming deficit as well as determine relevant group commonalities and differences. This includes an attempt to establish whether error types differentiate language-impaired children from adults, to determine effects of psycholinguistic variables on naming accuracies, and to link the results to genetic mechanisms and/or neural circuitry in the brain. A total of 89 (language-)impaired participants took part in this report: 24 adults with acquired aphasia, 20 adults with schizophrenia-spectrum disorder, 31 adults with relapsing-remitting multiple sclerosis, and 14 children with specific language impairment. The results of simultaneous multiple regression analyses for the errors in verb naming compared to the psycholinguistic variables for all language-impaired groups are reported and discussed in relation to models of lexical processing. This discussion will lead to considerations of genetic and/or neurobiological underpinnings: Presence of the noun–verb dissociation in focal and non-focal brain impairment make localization theories redundant, but support for wider neural network involvement.The patterns reported cannot be reduced to any one level of language processing, suggesting multiple interactions at different levels (e.g., receptive vs. expressive language abilities).Semantic-conceptual properties constrain syntactic properties with implications for phonological word form retrieval.Competition needs to be resolved at both conceptual and phonological levels of representation. Moreover, this study may provide a cross-pathological baseline that can be probed further with respect to recent suggestions concerning a reconsideration of open- vs. closed-class items, according to which verbs may actually fall into the

  16. Prevalence, symptoms and chronicity of ciguatera in New Caledonia: results from an adult population survey conducted in Noumea during 2005.

    PubMed

    Baumann, Francine; Bourrat, Marie-Blanche; Pauillac, Serge

    2010-10-01

    Ciguatera is a widespread ichthyosarcotoxism which causes gastrointestinal, neurological and cardiovascular disturbances. Investigations conducted by ORSTOM in 1992 highlighted a prevalence of 25% in the adult population of Noumea, New Caledonia. The main objective of our study was to estimate the prevalence of ciguatera and the persistence of symptoms by sex and by ethnicity among adult patients of a nurse clinic in Noumea in 2005. Investigations were conducted from 1st January to 15th June 2005. During this period, 559 patients were included: 165 males and 394 females. Among them, 37.8% were poisoned at least once in their life. This rate was independent of gender and ethnicity, but was significantly higher in age groups above 40 years. Neurological signs were more frequent (>80%) than gastrointestinal (<50%) and cardiac signs (<15%). Symptoms presented no difference between ethnic or gender groups, even for subjective signs. Most of poisonings were due to carnivorous fishes, but quite all species living in the lagoon were quoted. Symptoms persisted more than one year for 34% of the population, in both Melanesians and Caucasians. This study shows a significant increase of ciguatera prevalence, and its chronicity for 1/5 of European cases.

  17. Estimates and Projections of the Limited English Proficient Adult Population in Need of Employment Training.

    ERIC Educational Resources Information Center

    Willette, JoAnne; And Others

    A study estimated the size of the population of adults and out-of-school youth with limited English proficiency (LEP) who need vocational education and related employment services and projected the size of this population from the time of the study to the year 2000. Research procedures included a literature review, an analysis of 1980 U.S. census…

  18. Population growth rates of reef sharks with and without fishing on the great barrier reef: robust estimation with multiple models.

    PubMed

    Hisano, Mizue; Connolly, Sean R; Robbins, William D

    2011-01-01

    Overfishing of sharks is a global concern, with increasing numbers of species threatened by overfishing. For many sharks, both catch rates and underwater visual surveys have been criticized as indices of abundance. In this context, estimation of population trends using individual demographic rates provides an important alternative means of assessing population status. However, such estimates involve uncertainties that must be appropriately characterized to credibly and effectively inform conservation efforts and management. Incorporating uncertainties into population assessment is especially important when key demographic rates are obtained via indirect methods, as is often the case for mortality rates of marine organisms subject to fishing. Here, focusing on two reef shark species on the Great Barrier Reef, Australia, we estimated natural and total mortality rates using several indirect methods, and determined the population growth rates resulting from each. We used bootstrapping to quantify the uncertainty associated with each estimate, and to evaluate the extent of agreement between estimates. Multiple models produced highly concordant natural and total mortality rates, and associated population growth rates, once the uncertainties associated with the individual estimates were taken into account. Consensus estimates of natural and total population growth across multiple models support the hypothesis that these species are declining rapidly due to fishing, in contrast to conclusions previously drawn from catch rate trends. Moreover, quantitative projections of abundance differences on fished versus unfished reefs, based on the population growth rate estimates, are comparable to those found in previous studies using underwater visual surveys. These findings appear to justify management actions to substantially reduce the fishing mortality of reef sharks. They also highlight the potential utility of rigorously characterizing uncertainty, and applying multiple

  19. Population Growth Rates of Reef Sharks with and without Fishing on the Great Barrier Reef: Robust Estimation with Multiple Models

    PubMed Central

    Hisano, Mizue; Connolly, Sean R.; Robbins, William D.

    2011-01-01

    Overfishing of sharks is a global concern, with increasing numbers of species threatened by overfishing. For many sharks, both catch rates and underwater visual surveys have been criticized as indices of abundance. In this context, estimation of population trends using individual demographic rates provides an important alternative means of assessing population status. However, such estimates involve uncertainties that must be appropriately characterized to credibly and effectively inform conservation efforts and management. Incorporating uncertainties into population assessment is especially important when key demographic rates are obtained via indirect methods, as is often the case for mortality rates of marine organisms subject to fishing. Here, focusing on two reef shark species on the Great Barrier Reef, Australia, we estimated natural and total mortality rates using several indirect methods, and determined the population growth rates resulting from each. We used bootstrapping to quantify the uncertainty associated with each estimate, and to evaluate the extent of agreement between estimates. Multiple models produced highly concordant natural and total mortality rates, and associated population growth rates, once the uncertainties associated with the individual estimates were taken into account. Consensus estimates of natural and total population growth across multiple models support the hypothesis that these species are declining rapidly due to fishing, in contrast to conclusions previously drawn from catch rate trends. Moreover, quantitative projections of abundance differences on fished versus unfished reefs, based on the population growth rate estimates, are comparable to those found in previous studies using underwater visual surveys. These findings appear to justify management actions to substantially reduce the fishing mortality of reef sharks. They also highlight the potential utility of rigorously characterizing uncertainty, and applying multiple

  20. Estimating fish consumption and targeting high risk consumer populations in NJ and NY

    EPA Science Inventory

    An estimated 16.4% of US females of reproductive age (15 to 45 years) eat fish at least once per day. While fish is a good source of protein, with some species high in the omega-3 fatty acids that are associated with cardiovascular health, studies also indicate some fish and she...

  1. Evaluation of Fluoride Retention Due to Most Commonly Consumed Estuarine Fishes Among Fish Consuming Population of Andhra Pradesh as a Contributing Factor to Dental Fluorosis: A Cross-Sectional Study

    PubMed Central

    Ganta, Shravani; Nagaraj, Anup; Pareek, Sonia; Sidiq, Mohsin; Singh, Kushpal; Vishnani, Preeti

    2015-01-01

    Background Fluoride in drinking water is known for both beneficial and detrimental effects on health. The principal sources of fluoride include water, some species of vegetation, certain edible marine animals, dust and industrial processes. The purpose of this study was to evaluate the fluoride retention of most commonly consumed estuarine fishes among fish consuming population of Andhra Pradesh. Materials and Methods A cross-sectional study was conducted to evaluate the amount of fluoride retention due to ten most commonly consumed estuarine fishes as a contributing factor to Fluorosis by SPADNS Spectrophotometric method. The presence and severity of dental fluorosis among fish consuming population was recorded using Community Fluorosis Index. Statistical analysis was done using MedCalc v12.2.1.0 software. Results For Sea water fishes, the fluoride levels in bone were maximum in Indian Sardine (4.22 ppm). Amongst the river water fishes, the fluoride levels in bone were maximum in Catla (1.51 ppm). Also, the mean total fluoride concentrations of all the river fishes in skin, muscle and bone were less (0.86 ppm) as compared to the sea water fishes (2.59 ppm). It was unveiled that sea fishes accumulate relatively large amounts of Fluoride as compared to the river water fishes. The mean Community Fluorosis Index was found to be 1.06 amongst a sampled fish consuming population. Evaluation by Community Index for Dental fluorosis (CFI) suggested that fluorosis is of medium public health importance. Conclusion It was analysed that bone tends to accumulate more amount of fluoride followed by muscle and skin which might be due to the increased permeability and chemical trapping of fluoride inside the tissues. The amount of fluoride present in the fishes is directly related to the severity of fluorosis amongst fish consuming population, suggesting fishes as a contributing factor to fluorosis depending upon the dietary consumption. PMID:26266208

  2. Characterization of MHC class IIB for four endangered Australian freshwater fishes obtained from ecologically divergent populations.

    PubMed

    Bracamonte, Seraina E; Smith, Steve; Hammer, Michael; Pavey, Scott A; Sunnucks, Paul; Beheregaray, Luciano B

    2015-10-01

    Genetic diversity is an essential aspect of species viability, and assessments of neutral genetic diversity are regularly implemented in captive breeding and conservation programs. Despite their importance, information from adaptive markers is rarely included in such programs. A promising marker of significance in fitness and adaptive potential is the major histocompatibility complex (MHC), a key component of the adaptive immune system. Populations of Australian freshwater fishes are generally declining in numbers due to human impacts and the introduction of exotic species, a scenario of particular concern for members of the family Percichthyidae, several of which are listed as nationally vulnerable or endangered, and hence subject to management plans, captive breeding, and restoration plans. We used a next-generation sequencing approach to characterize the MHC IIB locus and provide a conservative description of its levels of diversity in four endangered percichthyids: Gadopsis marmoratus, Macquaria australasica, Nannoperca australis, and Nannoperca obscura. Evidence is presented for a duplicated MHC IIB locus, positively selected sites and recombination of MHC alleles. Relatively moderate levels of diversity were detected in the four species, as well as in different ecotypes within each species. Phylogenetic analyses revealed genus specific clustering of alleles and no allele sharing among species. There were also no shared alleles observed between two ecotypes within G. marmoratus and within M. australasica, which might be indicative of ecologically-driven divergence and/or long divergence times. This represents the first characterization and assessment of MHC diversity for Percichthyidae, and also for Australian freshwater fishes in general, providing key genetic resources for a vertebrate group of increasing conservation concern.

  3. Proposed methods and endpoints for defining and assessing adverse environmental impact (AEI) on fish communities/populations in Tennessee River reservoirs.

    PubMed

    Hickman, Gary D; Brown, Mary L

    2002-06-07

    Two multimetric indices have been developed to help address fish community (reservoir fish assemblage index [RFAI]) and individual population quality (sport fishing index [SFI]) in Tennessee River reservoirs. The RFAI, with characteristics similar to the index of biotic integrity (IBI) used in stream fish community determinations, was developed to monitor the existing condition of resident fish communities. The index, which incorporates standardized electrofishing of littoral areas and experimental gill netting for limnetic bottom-dwelling species, has been used to determine residential fish community response to various anthropogenic impacts in southeastern reservoirs. The SFI is a multimetric index designed to address the quality of the fishery for individual resident sport fish species in a particular lake or reservoir[4]. The SFI incorporates measures of fish population aspects and angler catch and pressure estimates. This paper proposes 70% of the maximum RFAI score and 10% above the average SFI score for individual species as "screening" endpoints for balanced indigenous populations (BIP) or adverse environmental impact (AEI). Endpoints for these indices indicate: (1) communities/populations are obviously balanced indigenous populations (BIP) indicating no adverse environmental impact (AEI), or are "screened out"; (2) communities/populations are considered to be potentially impacted; and (3) where the resident fish community/population should be considered adversely impacted. Suggestions are also made concerning how examination of individual metric scores can help determine the source or cause of the impact.

  4. The species flocks of East African cichlid fishes: recent advances in molecular phylogenetics and population genetics

    NASA Astrophysics Data System (ADS)

    Salzburger, Walter; Meyer, Axel

    With more than 3,000 species, the fish family Cichlidae is one of the most species-rich families of vertebrates. Cichlids occur in southern and central America, Africa, Madagascar, and India. The hotspot of their biodiversity is East Africa, where they form adaptive radiations composed of hundreds of endemic species in several lakes of various sizes and ages. The unparalleled species richness of East African cichlids has been something of a conundrum for evolutionary biologists and ecologists, since it has been in doubt whether these hundreds of species arose by allopatric speciation or whether it is necessary to invoke somewhat less traditional models of speciation, such as micro-allopatric, peripatric, or even sympatric speciation or evolution through sexual selection mediated by female choice. Ernst Mayr's analyses of these evolutionary uniquely diverse species assemblages have contributed to a more direct approach to this problem and have led to a deeper understanding of the patterns and processes that caused the formation of these huge groups of species. We review here recent molecular data on population differentiation and phylogenetics, which have helped to unravel, to some extent, the patterns and processes that led to the formation and ecological maintenance of cichlid species flocks. It is becoming apparent that sexually selected traits do play an important role in speciation in micro-allopatric or even sympatric settings. Species richness seems to be roughly correlated with the surface area, but not the age, of the lakes. We observe that the oldest lineages of a species flock of cichlids are often less species-rich and live in the open water or deepwater habitats. While the species flocks of the Lake Malawai and the Lake Victoria areas were shown to be monophyletic, the cichlid assemblage of Lake Tanganyika seems to consist of several independent species flocks. Cichlids emerge as an evolutionary model system in which many fundamental questions in

  5. Novel estimates of Aedes aegypti (Diptera: Culicidae) population size and adult survival based on Wolbachia releases.

    PubMed

    Ritchie, Scott A; Montgomery, Brian L; Hoffmann, Ary A

    2013-05-01

    The size of Aedes aegypti (L.) mosquito populations and adult survival rates have proven difficult to estimate because of a lack of consistent quantitative measures to equate sampling methods, such as adult trapping, to actual population size. However, such estimates are critical for devising control methods and for modeling the transmission of dengue and other infectious agents carried by this species. Here we take advantage of recent releases of Wolbachia-infected Ae. aegypti coupled with the results of ongoing monitoring to estimate the size of adult Ae. aegypti populations around Cairns in far north Queensland, Australia. Based on the association between released adults infected with Wolbachia and data from Biogents Sentinel traps, we show that data from two locations are consistent with population estimates of approximately 5-10 females per house and daily survival rates of 0.7-0.9 for the released Wolbachia-infected females. Moreover, we estimate that networks of Biogents Sentinel traps at a density of one per 15 houses capture around 5-10% of the adult population per week, and provide a rapid estimate of the absolute population size of Ae. aegypti. These data are discussed with respect to release rates and monitoring in future Wolbachia releases and also the levels of suppression required to reduce dengue transmission.

  6. Larval dispersal connects fish populations in a network of marine protected areas

    PubMed Central

    Planes, Serge; Jones, Geoffrey P.; Thorrold, Simon R.

    2009-01-01

    Networks of no-take marine protected areas (MPAs) have been widely advocated for the conservation of marine biodiversity. But for MPA networks to be successful in protecting marine populations, individual MPAs must be self-sustaining or adequately connected to other MPAs via dispersal. For marine species with a dispersive larval stage, populations within MPAs require either the return of settlement-stage larvae to their natal reserve or connectivity among reserves at the spatial scales at which MPA networks are implemented. To date, larvae have not been tracked when dispersing from one MPA to another, and the relative magnitude of local retention and connectivity among MPAs remains unknown. Here we use DNA parentage analysis to provide the first direct estimates of connectivity of a marine fish, the orange clownfish (Amphiprion percula), in a proposed network of marine reserves in Kimbe Bay, Papua New Guinea. Approximately 40% of A. percula larvae settling into anemones in an island MPA at 2 different times were derived from parents resident in the reserve. We also located juveniles spawned by Kimbe Island residents that had dispersed as far as 35 km to other proposed MPAs, the longest distance that marine larvae have been directly tracked. These dispersers accounted for up to 10% of the recruitment in the adjacent MPAs. Our findings suggest that MPA networks can function to sustain resident populations both by local replenishment and through larval dispersal from other reserves. More generally, DNA parentage analysis provides a direct method for measuring larval dispersal for other marine organisms. PMID:19307588

  7. Life-history diversity and its importance to population stability and persistence of a migratory fish: steelhead in two large North American watersheds.

    PubMed

    Moore, Jonathan W; Yeakel, Justin D; Peard, Dean; Lough, Jeff; Beere, Mark

    2014-09-01

    Life-history strategies can buffer individuals and populations from environmental variability. For instance, it is possible that asynchronous dynamics among different life histories can stabilize populations through portfolio effects. Here, we examine life-history diversity and its importance to stability for an iconic migratory fish species. In particular, we examined steelhead (Oncorhynchus mykiss), an anadromous and iteroparous salmonid, in two large, relatively pristine, watersheds, the Skeena and Nass, in north-western British Columbia, Canada. We synthesized life-history information derived from scales collected from adult steelhead (N = 7227) in these watersheds across a decade. These migratory fishes expressed 36 different manifestations of the anadromous life-history strategy, with 16 different combinations of freshwater and marine ages, 7·6% of fish performing multiple spawning migrations, and up to a maximum of four spawning migrations per lifetime. Furthermore, in the Nass watershed, various life histories were differently prevalent through time - three different life histories were the most prevalent in a given year, and no life history ever represented more than 45% of the population. These asynchronous dynamics among life histories decreased the variability of numerical abundance and biomass of the aggregated population so that it was > 20% more stable than the stability of the weighted average of specific life histories: evidence of a substantial portfolio effect. Year of ocean entry was a key driver of dynamics; the median correlation coefficient of abundance of life histories that entered the ocean the same year was 2·5 times higher than the median pairwise coefficient of life histories that entered the ocean at different times. Simulations illustrated how different elements of life-history diversity contribute to stability and persistence of populations. This study provides evidence that life-history diversity can dampen fluctuations in

  8. 17α-Ethinyl estradiol affects anxiety and shoaling behavior in adult male zebra fish (Danio rerio).

    PubMed

    Reyhanian, Nasim; Volkova, Kristina; Hallgren, Stefan; Bollner, Tomas; Olsson, Per-Erik; Olsén, Håkan; Hällström, Inger Porsch

    2011-09-01

    Ethinyl estradiol is a potent endocrine disrupting compound in fish and ubiquitously present in the aquatic environment. In this study, we exposed adult zebra fish (Danio rerio) males to 0, 5 or 25 ng Ethinyl estradiol/L for 14 days and analyzed the effects on non-reproductive behavior. Effects of treatment of the exposed males was shown by vitellogenin induction, while brain aromatase (CYP 19B) activity was not significantly altered. Both concentrations of Ethinyl estradiol significantly altered the behavior in the Novel tank test, where anxiety is determined as the tendency to stay at the bottom when introduced into an unfamiliar environment. The effects were, however, opposite for the two concentrations. Fish that were exposed to 5 ng/L had longer latency before upswim, fewer transitions to the upper half and shorter total time spent in the upper half compared with control fish, while 25 ng Ethinyl estradiol treatment resulted in shorter latency and more and longer visits to the upper half. The swimming activity of 25, but not 5 ng-exposed fish were slightly but significantly reduced, and these fish tended to spend a lot of time at the surface. We also studied the shoaling behavior as the tendency to leave a shoal of littermates trapped behind a Plexiglas barrier at one end of the test tank. The fish treated with Ethinyl estradiol had significantly longer latency before leaving shoal mates and left the shoal fewer times. Further, the fish exposed to 5 ng/L also spent significantly less time away from shoal than control fish. Fertilization frequency was higher in males exposed to 5 ng/L Ethinyl estradiol when compared with control males, while no spawning was observed after treatment with 25 ng/L. The testes from both treatment groups contained a normal distribution of spermatogenesis stages, and no abnormality in testis morphology could be observed. In conclusion, we have observed effects on two behaviors not related to reproduction in zebra fish males after

  9. Population-level assessments should be emphasized over community/ecosystem-level assessments. Environmental Sciences Division Publication No. 1535. [Concerning the impact of power plants on fish populations

    SciTech Connect

    Van Winkle, W

    1980-01-01

    Arguments are presented in favor of emphasizing population-level assessments over community/ecosystem-level assessments. The two approaches are compared on each of four issues: (1) the nature of entrainment/impingement impacts; (2) the ability to forecast reliably for a single fish population as contrasted to the ability to forecast for an aquatic community or ecosystem; (3) practical considerations involving money, manpower, time, and the need to make decisions; and (4) the nature of societal and economic concerns. The conclusion on each of these four issues is that population-level assessments provide the optimal approach for evaluating the effects of entrainment and impingement mortality.

  10. Habitat selection by breeding waterbirds at ponds with size-structured fish populations

    NASA Astrophysics Data System (ADS)

    Kloskowski, Janusz; Nieoczym, Marek; Polak, Marcin; Pitucha, Piotr

    2010-07-01

    Fish may significantly affect habitat use by birds, either as their prey or as competitors. Fish communities are often distinctly size-structured, but the consequences for waterbird assemblages remain poorly understood. We examined the effects of size structure of common carp ( Cyprinus carpio) cohorts together with other biotic and abiotic pond characteristics on the distribution of breeding waterbirds in a seminatural system of monocultured ponds, where three fish age classes were separately stocked. Fish age corresponded to a distinct fish size gradient. Fish age and total biomass, macroinvertebrate and amphibian abundance, and emergent vegetation best explained the differences in bird density between ponds. Abundance of animal prey other than fish (aquatic macroinvertebrates and larval amphibians) decreased with increasing carp age in the ponds. Densities of ducks and smaller grebes were strongly negatively associated with fish age/size gradient. The largest of the grebes, the piscivorous great crested grebe ( Podiceps cristatus), was the only species that preferred ponds with medium-sized fish and was positively associated with total fish biomass. Habitat selection by bitterns and most rallids was instead strongly influenced by the relative amount of emergent vegetation cover in the ponds. Our results show that fish size structure may be an important cue for breeding habitat choice and a factor affording an opportunity for niche diversification in avian communities.

  11. Reduced productivity in adult yellowfever mosquito (Diptera: Culicidae) populations

    SciTech Connect

    Rodriguez, P.H.; Hamm, W.J.; Garcia, F.; Garcia, M.; Schirf, V.

    1989-04-01

    Male and female Aedes aegypti (L.) mosquitoes of the laboratory strain ROCK were irradiated with 130 mw of argon 514.5 nm laser microbeams for 0.04, 0.25, 0.4, and 0.5 s, respectively. Egg production, percentage hatch, and productivity (average number of adults surviving after 3 wk) were used to assess mutagenic effects. Mortality was high for males in all laser radiation groups and increased with time of exposure. Except for the group treated for 0.25 s, significant reductions in total F1 progeny also were demonstrated for all other experimentals when male parents were exposed to laser radiation. Females showed a high mortality when subjected to 0.4- and 0.5-s laser radiation. No F1 progeny were produced when parental females were exposed for 0.25, 0.4, and 0.5 s. Numbers of F1 progeny from females exposed to 0.04 s of laser radiation were significantly reduced. A comparison of weekly mean number of progeny showed that the important differences in productivity occurred during the first and second week, respectively, when either male or female adult parents were subjected to laser radiation.

  12. Adult hippocampal neurogenesis in natural populations of mammals.

    PubMed

    Amrein, Irmgard

    2015-05-01

    This review will discuss adult hippocampal neurogenesis in wild mammals of different taxa and outline similarities with and differences from laboratory animals. It begins with a review of evidence for hippocampal neurogenesis in various mammals, and shows the similar patterns of age-dependent decline in cell proliferation in wild and domesticated mammals. In contrast, the pool of immature neurons that originate from proliferative activity varies between species, implying a selective advantage for mammals that can make use of a large number of these functionally special neurons. Furthermore, rapid adaptation of hippocampal neurogenesis to experimental challenges appears to be a characteristic of laboratory rodents. Wild mammals show species-specific, rather stable hippocampal neurogenesis, which appears related to demands that characterize the niche exploited by a species rather than to acute events in the life of its members. Studies that investigate adult neurogenesis in wild mammals are not numerous, but the findings of neurogenesis under natural conditions can provide new insights, and thereby also address the question to which cognitive demands neurogenesis may respond during selection.

  13. Effect of prehatching weightlessness on adult fish behavior in dynamic environments

    NASA Technical Reports Server (NTRS)

    Hoffman, R. B.; Salinas, G. A.; Boyd, J. F.; Baky, A. A.; Von Baumgarten, R. J.

    1978-01-01

    At 16-17 months of age, three groups of fish from the embryonated eggs in the ASTP killifish experiment were subjected to postflight tests consisting of rapidly changing environments. It was found that the group of fish with the least amount of development at orbital insertion (A-32) had a decreased rheotropism for both the moving background and the rotating water current tests when compared to ground control fish. Exposure to parabolic aircraft flight conditions revealed that the A-32 fish were less disoriented during zero gravity periods and were hypersensitive to high-gravity periods. These results suggested a modified vestibular competency due to a 9-d prehatching weightlessness exposure.

  14. Assessing the tolerance of fish and fish populations to environmental stress: The problems and methods of monitoring

    USGS Publications Warehouse

    Wedemeyer, G.A.; McLeay, D.; Goodyear, C.P.; Carins, V.W.; Hodson, P.V.; Nriagu, J.

    1984-01-01

    Environmental stress is an inescapable aspect of life in the aquatic environment. The chemical and physical demands of life underwater impose somewhat rigorous constraints on aquatic species (Smith, 1982a). Superimposed on such demands may be the additional. physiological constraints of particular ecological niches. It is true that aquatic species are adapted to these conditions, but this does not imply the absence of energy drains (Lugo, 1978). For example, thermophilic fishes must still cope physiologically with the demands of high temperatures even though they are adapted to high temperatures per se.

  15. Does cannibalism of larvae by adults affect settlement and connectivity of mussel populations?

    NASA Astrophysics Data System (ADS)

    Porri, Francesca; Jordaan, Tembisa; McQuaid, Christopher D.

    2008-09-01

    Intertidal population dynamics are driven by a complex series of processes, including larval supply and the possibility of larval predation by benthic animals such as filter-feeders. We hypothesised that cannibalism by adults could play a major role in the population connectivity of mussel populations by removing larvae as they attempt to settle in the adult habitat. Specifically, we tested hypotheses that consumption of mussel larvae by adults removes a significant proportion of potential settlers and is influenced by both settlement intensity and tidal state (flooding or ebbing). Predation of mussel larvae by adult mussels was investigated on incoming and ebbing tides during four spring tides by analysing the gut contents of adult Perna perna and Mytilus galloprovincialis collected from the low intertidal mussel zone between October 2005 and January 2006. Consumption rates were then compared with estimates of successful settler densities on natural beds. The results showed that mortality of competent mussel larvae through adult ingestion removes up to 77% a of potential settlers. Rates of larval consumption were highest during months of intense settlement, suggesting that mussels feed opportunistically, filtering a relatively fixed volume of water and removing particles, including larvae, in proportion to their densities in the water. Rates of larviphagy were also higher during receding than incoming tides. We suggest that this is due to changes in larval density or, more probably, in adult filtration efficiency that are related to the state of the tide. Despite significant effects of both tidal state and settlement intensity on rates of larval ingestion, neither had a significant effect on the proportion of potential settlers removed. During settlement more than half of all potential settlers are lost through cannibalism, with potentially serious consequences for population maintenance. The results highlight the paradoxical nature of the evolution of settlement

  16. Estimating total population size for adult female sea turtles: Accounting for non-nesters

    USGS Publications Warehouse

    Kendall, W.L.; Richardson, J.I.; Rees, Alan F.

    2008-01-01

    Assessment of population size and changes therein is important to sea turtle management and population or life history research. Investigators might be interested in testing hypotheses about the effect of current population size or density (number of animals per unit resource) on future population processes. Decision makers might want to determine a level of allowable take of individual turtles of specified life stage. Nevertheless, monitoring most stages of sea turtle life histories is difficult, because obtaining access to individuals is difficult. Although in-water assessments are becoming more common, nesting females and their hatchlings remain the most accessible life stages. In some cases adult females of a given nesting population are sufficiently philopatric that the population itself can be well defined. If a well designed tagging study is conducted on this population, survival, breeding probability, and the size of the nesting population in a given year can be estimated. However, with published statistical methodology the size of the entire breeding population (including those females skipping nesting in that year) cannot be estimated without assuming that each adult female in this population has the same probability of nesting in a given year (even those that had just nested in the previous year). We present a method for estimating the total size of a breeding population (including nesters those skipping nesting) from a tagging study limited to the nesting population, allowing for the probability of nesting in a given year to depend on an individual's nesting status in the previous year (i.e., a Markov process). From this we further develop estimators for rate of growth from year to year in both nesting population and total breeding population, and the proportion of the breeding population that is breeding in a given year. We also discuss assumptions and apply these methods to a breeding population of hawksbill sea turtles (Eretmochelys imbricata) from

  17. Differences in the Metabolic Rates of Exploited and Unexploited Fish Populations: A Signature of Recreational Fisheries Induced Evolution?

    PubMed Central

    Hessenauer, Jan-Michael; Vokoun, Jason C.; Suski, Cory D.; Davis, Justin; Jacobs, Robert; O’Donnell, Eileen

    2015-01-01

    Non-random mortality associated with commercial and recreational fisheries have the potential to cause evolutionary changes in fish populations. Inland recreational fisheries offer unique opportunities for the study of fisheries induced evolution due to the ability to replicate study systems, limited gene flow among populations, and the existence of unexploited reference populations. Experimental research has demonstrated that angling vulnerability is heritable in Largemouth Bass Micropterus salmoides, and is correlated with elevated resting metabolic rates (RMR) and higher fitness. However, whether such differences are present in wild populations is unclear. This study sought to quantify differences in RMR among replicated exploited and unexploited populations of Largemouth Bass. We collected age-0 Largemouth Bass from two Connecticut drinking water reservoirs unexploited by anglers for almost a century, and two exploited lakes, then transported and reared them in the same pond. Field RMR of individuals from each population was quantified using intermittent-flow respirometry. Individuals from unexploited reservoirs had a significantly higher mean RMR (6%) than individuals from exploited populations. These findings are consistent with expectations derived from artificial selection by angling on Largemouth Bass, suggesting that recreational angling may act as an evolutionary force influencing the metabolic rates of fishes in the wild. Reduced RMR as a result of fisheries induced evolution may have ecosystem level effects on energy demand, and be common in exploited recreational populations globally. PMID:26039091

  18. Differences in the metabolic rates of exploited and unexploited fish populations: a signature of recreational fisheries induced evolution?

    PubMed

    Hessenauer, Jan-Michael; Vokoun, Jason C; Suski, Cory D; Davis, Justin; Jacobs, Robert; O'Donnell, Eileen

    2015-01-01

    Non-random mortality associated with commercial and recreational fisheries have the potential to cause evolutionary changes in fish populations. Inland recreational fisheries offer unique opportunities for the study of fisheries induced evolution due to the ability to replicate study systems, limited gene flow among populations, and the existence of unexploited reference populations. Experimental research has demonstrated that angling vulnerability is heritable in Largemouth Bass Micropterus salmoides, and is correlated with elevated resting metabolic rates (RMR) and higher fitness. However, whether such differences are present in wild populations is unclear. This study sought to quantify differences in RMR among replicated exploited and unexploited populations of Largemouth Bass. We collected age-0 Largemouth Bass from two Connecticut drinking water reservoirs unexploited by anglers for almost a century, and two exploited lakes, then transported and reared them in the same pond. Field RMR of individuals from each population was quantified using intermittent-flow respirometry. Individuals from unexploited reservoirs had a significantly higher mean RMR (6%) than individuals from exploited populations. These findings are consistent with expectations derived from artificial selection by angling on Largemouth Bass, suggesting that recreational angling may act as an evolutionary force influencing the metabolic rates of fishes in the wild. Reduced RMR as a result of fisheries induced evolution may have ecosystem level effects on energy demand, and be common in exploited recreational populations globally.

  19. Evolution of increased adult longevity in Drosophila melanogaster populations selected for adaptation to larval crowding.

    PubMed

    Shenoi, V N; Ali, S Z; Prasad, N G

    2016-02-01

    In holometabolous animals such as Drosophila melanogaster, larval crowding can affect a wide range of larval and adult traits. Adults emerging from high larval density cultures have smaller body size and increased mean life span compared to flies emerging from low larval density cultures. Therefore, adaptation to larval crowding could potentially affect adult longevity as a correlated response. We addressed this issue by studying a set of large, outbred populations of D. melanogaster, experimentally evolved for adaptation to larval crowding for 83 generations. We assayed longevity of adult flies from both selected (MCUs) and control populations (MBs) after growing them at different larval densities. We found that MCUs have evolved increased mean longevity compared to MBs at all larval densities. The interaction between selection regime and larval density was not significant, indicating that the density dependence of mean longevity had not evolved in the MCU populations. The increase in longevity in MCUs can be partially attributed to their lower rates of ageing. It is also noteworthy that reaction norm of dry body weight, a trait probably under direct selection in our populations, has indeed evolved in MCU populations. To the best of our knowledge, this is the first report of the evolution of adult longevity as a correlated response of adaptation to larval crowding.

  20. Population Structure and Adaptive Divergence in a High Gene Flow Marine Fish: The Small Yellow Croaker (Larimichthys polyactis)

    PubMed Central

    Xue, Dong-Xiu; Gao, Tian-Xiang; Liu, Jin-Xian

    2016-01-01

    The spatial distribution of genetic diversity has been long considered as a key component of policy development for management and conservation of marine fishes. However, unraveling the population genetic structure of migratory fish species is challenging due to high potential for gene flow. Despite the shallow population differentiation revealed by putatively neutral loci, the higher genetic differentiation with panels of putatively adaptive loci could provide greater resolution for stock identification. Here, patterns of population differentiation of small yellow croaker (Larimichthys polyactis) were investigated by genotyping 15 highly polymorphic microsatellites in 337 individuals of 15 geographic populations collected from both spawning and overwintering grounds. Outlier analyses indicated that the locus Lpol03 might be under directional selection, which showed a strong homology with Grid2 gene encoding the glutamate receptor δ2 protein (GluRδ2). Based on Lpol03, two distinct clusters were identified by both STRUCTURE and PCoA analyses, suggesting that there were two overwintering aggregations of L. polyactis. A novel migration pattern was suggested for L. polyactis, which was inconsistent with results of previous studies based on historical fishing yield statistics. These results provided new perspectives on the population genetic structure and migratory routes of L. polyactis, which could have significant implications for sustainable management and utilization of this important fishery resource. PMID:27100462

  1. Caregiver Abuse of Chicago Chinese Older Adults in a Community-Dwelling Population

    PubMed Central

    Dong, Xin Qi; Li, Ge

    2016-01-01

    Objectives This study aimed to examine the prevalence and correlates of elder abuse reported by adult children among U.S Chinese populations. Method A community-based participatory research approach was implemented. A total of 548 Chinese adult children aged 21 years and over participated in this study. Elder abuse reported by adult children was assessed using Caregiver Abuse Screen (CASE). Results This study found a prevalence of 59.8%for elder abuse among 548 adult children. Younger age (r = −0.10, p < .05), higher level of education (r = 0.20, p < .001), higher income (r = 0.14, p < .01), more years in the U.S. (r = 0.12, p < .05), not born in Mainland China (r = −0.13, p < .01), and English-speaking (r = 0.16, p < .001) were positively correlated with elder abuse reported by adult children. Discussion Elder abuse by adult children is prevalent among U.S. Chinese populations. It is necessary for researchers, health care providers and policy makers to put more attention on elder abuse by adult children. Longitudinal research is needed to explore the risk factors associated with elder abuse by adult children. Health care providers should improve detection of elder abuse and support at-risk caregivers. Policy makers may consider cultural sensitive approaches to address elder abuse. PMID:27606358

  2. Contrasting Population and Diet Influences on Gut Length of an Omnivorous Tropical Fish, the Trinidadian Guppy (Poecilia reticulata).

    PubMed

    Zandonà, Eugenia; Auer, Sonya K; Kilham, Susan S; Reznick, David N

    2015-01-01

    Phenotypic plasticity is advantageous for organisms that live in variable environments. The digestive system is particularly plastic, responding to changes in diet. Gut length is the result of a trade-off between maximum nutrient absorption and minimum cost for its maintenance and it can be influenced by diet and by evolutionary history. We assessed variation in gut length of Trinidadian guppies (Poecilia reticulata) as a function of diet, season, ontogeny, and local adaptation. Populations of guppies adapted to different predation levels have evolved different life history traits and have different diets. We sampled guppies from sites with low (LP) and high predation (HP) pressure in the Aripo and Guanapo Rivers in Trinidad. We collected fish during both the dry and wet season and assessed their diet and gut length. During the dry season, guppies from HP sites fed mostly on invertebrates, while guppies in the LP sites fed mainly on detritus. During the wet season, the diet of LP and HP populations became very similar. We did not find strong evidence of an ontogenetic diet shift. Gut length was negatively correlated with the proportion of invertebrates in diet across fish from all sites, supporting the hypothesis that guppy digestive systems adapt in length to changes in diet. Population of origin also had an effect on gut length, as HP and LP fish maintained different gut lengths even in the wet season, when their diets were very similar and individuals in both types of populations fed mostly on detritus. Thus, both environment and population of origin influenced guppies gut length, but population of origin seemed to have a stronger effect. Our study also showed that, even in omnivorous fish, gut length adapted to different diets, being more evident when the magnitude of difference between animal and plant material in the diet was very large.

  3. Response of fish populations to natural channel design restoration in streams of the Catskill Mountains, New York

    USGS Publications Warehouse

    Baldigo, Barry P.; Warren, D.R.; Ernst, A.G.; Mulvihill, C.I.

    2008-01-01

    Many streams and rivers throughout North America have been extensively straightened, widened, and hardened since the middle 1800s, but related effects on aquatic ecosystems have seldom been monitored, described, or published. Beginning in the early 1990s, reach-level restoration efforts began to base projects on natural channel design (NCD) techniques and Rosgen's (1994b, 1996) river classification system in an effort to duplicate or mimic stable reference reach geomorphology. Four reaches in three streams of the Catskill Mountains, New York, were restored from 2000 to 2002 using NCD techniques to decrease bed and bank erosion rates, decrease sediment loads, and improve water quality. The effects of restoration on the health of fish assemblages were assessed through a before-after, control-impact (BACI) study design to quantify the net changes in population and community indices at treatment reaches relative to index changes at unaltered reference reaches from 1999 to 2004. After restoration, community richness and biomass at treatment reaches increased by more than one-third. Changes in fish communities were caused mainly by shifts in dominant species populations; fish community biomass and total fish abundance were generally dominated by daces or daces and sculpins before restoration and by one or more salmonid species after restoration. Density and biomass of eastern blacknose dace Rhinichthys atratulus, longnose dace R. cataractae, and slimy sculpin Cottus cognatus did not change appreciably, whereas net salmonid density and biomass increased substantially after restoration. These changes were driven primarily by large increases in populations of brown trout Salmo trutta. The findings demonstrate that the structure, function, and ultimately the health of resident fish populations and communities can be improved, at least over the short term, through NCD restoration in perturbed streams of the Catskill Mountains. ?? Copyright by the American Fisheries Society

  4. Large-scale, multidirectional larval connectivity among coral reef fish populations in the Great Barrier Reef Marine Park.

    PubMed

    Williamson, David H; Harrison, Hugo B; Almany, Glenn R; Berumen, Michael L; Bode, Michael; Bonin, Mary C; Choukroun, Severine; Doherty, Peter J; Frisch, Ashley J; Saenz-Agudelo, Pablo; Jones, Geoffrey P

    2016-12-01

    Larval dispersal is the key process by which populations of most marine fishes and invertebrates are connected and replenished. Advances in larval tagging and genetics have enhanced our capacity to track larval dispersal, assess scales of population connectivity, and quantify larval exchange among no-take marine reserves and fished areas. Recent studies have found that reserves can be a significant source of recruits for populations up to 40 km away, but the scale and direction of larval connectivity across larger seascapes remain unknown. Here, we apply genetic parentage analysis to investigate larval dispersal patterns for two exploited coral reef groupers (Plectropomus maculatus and Plectropomus leopardus) within and among three clusters of reefs separated by 60-220 km within the Great Barrier Reef Marine Park, Australia. A total of 69 juvenile P. maculatus and 17 juvenile P. leopardus (representing 6% and 9% of the total juveniles sampled, respectively) were genetically assigned to parent individuals on reefs within the study area. We identified both short-distance larval dispersal within regions (200 m to 50 km) and long-distance, multidirectional dispersal of up to ~250 km among regions. Dispersal strength declined significantly with distance, with best-fit dispersal kernels estimating median dispersal distances of ~110 km for P. maculatus and ~190 km for P. leopardus. Larval exchange among reefs demonstrates that established reserves form a highly connected network and contribute larvae for the replenishment of fished reefs at multiple spatial scales. Our findings highlight the potential for long-distance dispersal in an important group of reef fishes, and provide further evidence that effectively protected reserves can yield recruitment and sustainability benefits for exploited fish populations.

  5. Studies of the limnology, fish populations, and fishery of Turquoise Lake, Colorado - 1979-80

    SciTech Connect

    Nesler, T.P.

    1981-07-01

    Turquoise Lake is one of the primary storage reservoirs in the Fryingpan-Arkansas Water Project and provides supplementary water by conduit to the MT. Elbert Forebay-Twin Lakes system for pump-back storage power generation. The reservoir may be characterized as a dimictic, cold-water lake that is well oxygenated, relatively unbuffed, and slightly acidic. The lake may be classified as oligotrophic on the basis of total dissolved solids, algal nutrients (N-P), and chlorophyll concentrations. Depletion of dissolved oxygen occurs regularly in the hypolimnion during late summer and late winter. Turquoise Lake is limnologically similar to Twin Lakes (Colo.) in most respects. Data contained in this report are useful to those interested in the limnology of high mountain lakes, including physical-chemical parameters, chlorophyll, plankton, and fish populations. Turquoise Lake provides source water to the Mt. Elbert forebay. Thus the baseline data provided here will be helpful in assessing the effects of pumped-storage powerplant operation on the limnology of Twin Lakes, Colo.

  6. Maintaining population persistence in the face of an extremely altered hydrograph: implications for three sensitive fishes in a tributary of the Green River, Utah

    USGS Publications Warehouse

    Bottcher, Jared L.

    2009-01-01

    The ability of an organism to disperse to suitable habitats, especially in modified and fragmented systems, determines individual fitness and overall population viability. The bluehead sucker (Catostomus discobolus), flannelmouth sucker (Catostomus latipinnis), and roundtail chub (Gila robusta) are three species native to the upper Colorado River Basin that now occupy only 50% of their historic range. Despite these distributional declines, populations of all three species are present in the San Rafael River, a highly regulated tributary of the Green River, Utah, providing an opportunity for research. Our goal was to determine the timing and extent of movement, habitat preferences, and limiting factors, ultimately to guide effective management and recovery of these three species. In 2007-2008, we sampled fish from 25 systematically selected, 300-m reaches in the lower 64 km of the San Rafael River, spaced to capture the range of species, life-stages, and habitat conditions present. We implanted all target species with a passive integrated transponder (PIT) tag, installed a passive PIT tag antennae, and measured key habitat parameters throughout each reach and at the site of native fish capture. We used random forest modeling to identify and rank the most important abiotic and biotic predictor variables, and reveal potential limiting factors in the San Rafael River. While flannelmouth sucker were relatively evenly distributed within our study area, highest densities of roundtail chub and bluehead sucker occurred in isolated, upstream reaches characterized by complex habitat. In addition, our movement and length-frequency data indicate downstream drift of age-0 roundtail chub, and active upstream movement of adult flannelmouth sucker, both from source populations, providing the lower San Rafael River with colonists. Our random forest analysis highlights the importance of pools, riffles, and distance-to-source populations, suggesting that bluehead sucker and roundtail

  7. Limited variability in upper thermal tolerance among pure and hybrid populations of a cold-water fish

    PubMed Central

    Wells, Zachery R. R.; McDonnell, Laura H.; Chapman, Lauren J.; Fraser, Dylan J.

    2016-01-01

    As climate warming threatens the persistence of many species and populations, it is important to forecast their responses to warming thermal regimes. Climate warming often traps populations in smaller habitat fragments, not only changing biotic parameters, but potentially decreasing adaptive potential by decreasing genetic variability. We examined the ability of six genetically distinct and different-sized populations of a cold-water fish (brook trout, Salvelinus fontinalis) to tolerate acute thermal warming and whether this tolerance could be altered by hybridizing populations. Critical thermal maximum (CTmax) assays were conducted on juveniles from each population to assess thermal tolerance, and the agitation temperature was recorded for assessing behavioural changes to elevated temperatures. An additional metric, which we have called the ‘CTmax–agitation window’ (CTmax minus agitation temperature), was also assessed. The CTmax differed between five out of 15 population pairs, although the maximal CTmax difference was only 0.68°C (29.11–29.79°C). Hybridization between one large population and two small populations yielded no obvious heterosis in mean CTmax, and no differences in agitation temperature or CTmax–agitation window were detected among pure populations or hybrids. Summer variation in temperature within each stream was negatively correlated with mean CTmax and mean CTmax–agitation window, although the maximal difference was small. Despite being one of the most phenotypically divergent and plastic north temperate freshwater fishes, our results suggest that limited variability exists in CTmax among populations of brook trout, regardless of their population size, standing genetic variation and differing natural thermal regimes (temperature variation, minimum and maximum). This study highlights the level to which thermal tolerance is conserved between isolated populations of a vertebrate species, in the face of climate warming. PMID:27990291

  8. Bronchodilator Responsiveness and Reported Respiratory Symptoms in an Adult Population

    PubMed Central

    Tan, Wan C.; Bourbeau, Jean; Hernandez, Paul; Chapman, Kenneth R.; Cowie, Robert; FitzGerald, J. Mark; Aaron, Shawn; Marciniuk, Darcy D.; Maltais, Francois; Buist, A. Sonia; O’Donnell, Denis E.; Sin, Don D.

    2013-01-01

    Background The relationship between patient-reported symptoms and objective measures of lung function is poorly understood. Aim To determine the association between responsiveness to bronchodilator and respiratory symptoms in random population samples. Methods 4669 people aged 40 years and older from 8 sites in Canada completed interviewer-administered respiratory questionnaires and performed spirometry before and after administration of 200 ug of inhaled salbutamol. The effect of anthropometric variables, smoking exposure and doctor-diagnosed asthma (DDA) on bronchodilator responsiveness in forced expiratory volume in 1 second (FEV1) and in forced vital capacity (FVC) were evaluated. Multiple logistic regression was used to test for association between quintiles of increasing changes in FEV1 and in FVC after bronchodilator and several respiratory symptoms. Results Determinants of bronchodilator change in FEV1 and FVC included age, DDA, smoking, respiratory drug use and female gender [p<0.005 to p<0.0001 ]. In subjects without doctor-diagnosed asthma or COPD, bronchodilator response in FEV1 was associated with wheezing [p for trend<0.0001], while bronchodilator response for FVC was associated with breathlessness. [p for trend <0.0001]. Conclusions Bronchodilator responsiveness in FEV1 or FVC are associated with different respiratory symptoms in the community. Both flow and volume bronchodilator responses are useful parameters which together can be predictive of both wheezing and breathlessness in the general population. PMID:23554960

  9. Effects on life history variables and population dynamics following maternal metal exposure in the live-bearing fish Gambusia affinis.

    PubMed

    Cazan, Alfy Morales; Klerks, Paul L

    2015-04-01

    This study investigated the effect of maternal copper and maternal cadmium exposure on life history variables and population dynamics in a live-bearing fish species. Gravid females were exposed to copper, cadmium, or background metal levels (control); maternal transfer of the metals was previously demonstrated using the exact same design. Each female's first brood, born after the exposure, was subdivided into two groups. One group was raised in the laboratory, to assess time-to and size-at sexual maturity, reproductive output and other life history variables. Offspring from the other group were used to start four mesocosm populations for each treatment. These populations were sampled monthly, for about 18 months, to assess population dynamics. For the laboratory-reared fish, offspring of copper-exposed females reached sexual maturity at a smaller size than did offspring from the other treatments. Maternal copper exposure and maternal cadmium exposure both resulted in fewer broods and an increase in gestation time. No impacts were detected for brood size, inter-brood interval, time-to-sexual-maturity, or life span. In the greenhouse population study, no effect of maternal copper or cadmium exposure was evident for population parameters, other than that the relative abundance of juveniles and/or newborns was reduced in populations established with offspring of the exposed females. This study provided evidence that a short-term metal exposure of gravid females can negatively affect their offspring's life history variables and potentially influence population dynamics in a life-bearing fish species.

  10. Temperament profiles in personality disorders among a young adult population.

    PubMed

    Kantojärvi, Liisa; Miettunen, Jouko; Veijola, Juha; Läksy, Kristian; Karvonen, Juha T; Ekelund, Jesper; Järvelin, Marjo-Riitta; Lichtermann, Dirk; Joukamaa, Matti

    2008-01-01

    The objective of this study was to describe the temperament dimension profiles assessed by the Temperament and Character Inventory (TCI) among young adults with the DSM-III-R personality disorder (PD). Our hypothesis was that PD clusters and separate PDs can be distinguished from one another by their specific temperament profiles. As a part of the 31-year follow-up survey of the prospective Northern Finland 1966 Birth Cohort, the cohort members living in the city of Oulu at the age of 31 years (n=1609) were invited to participate in a two-phase field study. The Structured Clinical Interview for DSM-III-R for PDs (SCID-II) was used as diagnostic instrument. The final study sample consisted of the 1311 subjects who had completed the Hopkins Symptom Check List-25 questionnaire for screening and had given a written informed consent. Of the 321 SCID interviewed subjects, 74 met the criteria for at least one PD and had completed the TCI. The mean TCI scores of subjects with PD and control subjects without PD (n=910) were compared. Low Novelty Seeking, high Harm Avoidance and low Reward Dependence characterized cluster A and C PDs. Subjects with a cluster B PD did not differ from controls, except for Novelty Seeking, which was high. The temperament dimensions could not distinguish different PDs very well, with the only exception of persons with obsessive-compulsive PD. PD clusters were associated with different profiles of temperament, lending some support for Cloninger's typology.

  11. Population structure and reproductive period of two introduced fish species in a Brazilian semiarid region reservoir.

    PubMed

    Sousa, Marla Melise de Oliveira; Lopes, Suzany Iasnaya Moreira; da Costa, Rodrigo Silva; Novaes, José Luís Costa

    2015-09-01

    The Amazonian fish species Plagioscion squamosissimus (Sciaenidae) and Cichla monoculus Cichlidae), have been widely introduced into different reservoirs in Brazil, and have caused many negative mpacts on local fish fauna. The aim of this study was to evaluate the population structure (abundance, length structure, length-weight relationship, sex ratio, and length at first maturity) and the reprodutive period of these wo species in the Santa Cruz Reservoir (built in 2002), located in the Brazilian semiarid region, for their adequate management and local species conservation policies. Specimens were collected quarterly in eight sites from February 2010 to November 2013 using gillnets (12 to 70 mm mesh between adjacent knots). The specimens captured were counted and the following biometric and biological data were analysed: standard length, total weight, and reproductive data, such as, sex, weight and gonadal maturity stage. The species abundances were estimated by CPUE and expressed as the number of individuals per gill net area x gill net exposition time (m2 x h); length frequency histograms were built with intervals of 5 cm. The length-weight parameters were estimated with a linear regression after a logarithmic transformation of the data. With the reproductive data we estimated sex ratio, reproduction period and length at first maturity (L50). We captured a total of 1,071 specimens of P. squamosissimus and 156 specimens of C. monoculus. Both species showed higher abundances in 2010, 0.004306 m2 x h and 0.00022 m2 x h, respectively, but this parameter decreased from 2010 to 2013. Standard length ranged between 6.4 and 46.2 cm for P. squamosissimus (20.025.0 cm was the most frequent class), and 7.0 and 38.7 cm for C. monocidus (10.0-15.0 cm was the most frequent class). The length-weight relationships were described by the following equations: log10Wt = -1.8349+3.0899log10Lp and R2= 0.9795 for P. squamosissimus, and log10 Wt = -1.7944+3.0885log10Lp and Wt = 0

  12. Mortality Among Adults With Intellectual Disability in England: Comparisons With the General Population

    PubMed Central

    Hosking, Fay J.; Shah, Sunil M.; Harris, Tess; DeWilde, Stephen; Beighton, Carole; Cook, Derek G.

    2016-01-01

    Objectives. To describe mortality among adults with intellectual disability in England in comparison with the general population. Methods. We conducted a cohort study from 2009 to 2013 using data from 343 general practices. Adults with intellectual disability (n = 16 666; 656 deaths) were compared with age-, gender-, and practice-matched controls (n = 113 562; 1358 deaths). Results. Adults with intellectual disability had higher mortality rates than controls (hazard ratio [HR] = 3.6; 95% confidence interval [CI] = 3.3, 3.9). This risk remained high after adjustment for comorbidity, smoking, and deprivation (HR = 3.1; 95% CI = 2.7, 3.4); it was even higher among adults with intellectual disability and Down syndrome or epilepsy. A total of 37.0% of all deaths among adults with intellectual disability were classified as being amenable to health care intervention, compared with 22.5% in the general population (HR = 5.9; 95% CI = 5.1, 6.8). Conclusions. Mortality among adults with intellectual disability is markedly elevated in comparison with the general population, with more than a third of deaths potentially amenable to health care interventions. This mortality disparity suggests the need to improve access to, and quality of, health care among people with intellectual disability. PMID:27310347

  13. What Is the Prevalence of Adult ADHD? Results of a Population Screen of 966 Adults

    ERIC Educational Resources Information Center

    Faraone, Stephen V.; Biederman, Joseph

    2005-01-01

    To provide a better estimate of the prevalence of ADHD in adulthood, the authors complete a telephone survey of 966 randomly selected adults. They compute two diagnoses from the survey data. Participants meeting "Diagnostic and Statistical Manual of Mental Disorders" (4th ed.) criteria for both childhood and adulthood are defined as narrow ADHD.…

  14. Effects of a single intensive harvest event on fish populations inside a customary marine closure

    NASA Astrophysics Data System (ADS)

    Jupiter, S. D.; Weeks, R.; Jenkins, A. P.; Egli, D. P.; Cakacaka, A.

    2012-06-01

    In September 2008, the villagers of Kia Island, Fiji, opened their customary managed closure (Cakaulevu tabu) to fishing for a fundraiser that lasted for 5 weeks. We report on opportunistic before-after-control-impact surveys describing changes to coral reef communities both 4 weeks into the harvest and 1 year later compared with pre-harvest conditions. Prior to the harvest, there was a gradient in mean fish abundance and biomass per transect, with highest levels in the north of the closure (250 fish transect-1, 8,145.8 kg ha-1), intermediate levels in the south of the closure (159 fish transect-1, 4,672.1 kg ha-1) and lowest levels in the control area open to fishing (109 fish transect-1, 594.0 kg ha-1). During the harvest, there were extensive depletions in large-bodied, primary targeted fish species, with significant loss in biomass of Acanthuridae and Carangidae in the north and Lutjanidae and Serranidae in the south. We also observed significant increases in Acanthuridae, Lethrinidae and Scaridae in the control, suggesting a "bail-out" effect whereby fish left the closure in response to a rapid increase in fishing pressure. These changes were coupled with a large increase in turf algal cover at all survey areas, despite a large numerical increase in small, roving acanthurids (e.g., Ctenochaetus striatus) and scarids (e.g., Chlorurus sordidus). By 1 year later, fish biomass was significantly lower within the closure than before the harvest, while values in the control returned to pre-harvest levels, suggesting non-compliance with the reinstated fishing ban. We use the lessons learned from this event to suggest recommendations for promoting effective management of periodically harvested customary closures that are a common feature across much of Oceania.

  15. Non-stressful temperature effect on oxidative balance and life history traits in adult fish (Oryzias latipes).

    PubMed

    Hemmer-Brepson, C; Replumaz, L; Romestaing, C; Voituron, Y; Daufresne, M

    2014-01-15

    Temperature is well known to affect many biological and ecological traits, especially in ectotherms. From a physiological point of view, temperature is also positively correlated to metabolism and is often associated with an increase in reactive oxygen species (ROS) production. It has recently been suggested that ROS play a role in lifespan and resource allocation. However, only a few authors have attempted to explore the relationships between temperature, resource allocation and oxidative balance in ectotherms. Here, we measured the effect of temperature on growth, reproductive effort, offspring quantity and quality, hatching and survival rates, and the associated proximal costs, which were evaluated through the quantification of oxidative balance elements. We reared adult fish (Oryzias latipes) at two non-stressful temperatures (20 and 30°C) during a relatively long period (4 months, approximately the entire adult life). The results show a trade-off between reproduction and maintenance because investment toward growth could be neglected at the adult stage (confirmed by our results). Intriguingly, ROS-dependent damages did not differ between the two groups, probably because of the higher rate of activation of the antioxidant enzyme superoxide dismutase for warm-acclimated fish. The allocation toward antioxidant defences is associated with an earlier reproduction and a lower quality of offspring. These interesting results bring new perspectives in terms of the prediction of the impact of global warming on biota through the use of ecological theories based on oxidative balance and metabolism.

  16. High-frequency audiometric assessment of a young adult population.

    PubMed

    Green, D M; Kidd, G; Stevens, K N

    1987-02-01

    The hearing thresholds of 37 young adults (18-26 years) were measured at 13 frequencies (8, 9,10,...,20 kHz) using a newly developed high-frequency audiometer. All subjects were screened at 15 dB HL at the low audiometric frequencies, had tympanometry within normal limits, and had no history of significant hearing problems. The audiometer delivers sound from a driver unit to the ear canal through a lossy tube and earpiece providing a source impedance essentially equal to the characteristic impedance of the tube. A small microphone located within the earpiece is used to measure the response of the ear canal when an impulse is applied at the driver unit. From this response, a gain function is calculated relating the equivalent sound-pressure level of the source to the SPL at the medial end of the ear canal. For the subjects tested, this gain function showed a gradual increase from 2 to 12 dB over the frequency range. The standard deviation of the gain function was about 2.5 dB across subjects in the lower frequency region (8-14 kHz) and about 4 dB at the higher frequencies. Cross modes and poor fit of the earpiece to the ear canal prevented accurate calibration for some subjects at the highest frequencies. The average SPL at threshold was 23 dB at 8 kHz, 30 dB at 12 kHz, and 87 dB at 18 kHz. Despite the homogeneous nature of the sample, the younger subjects in the sample had reliably better thresholds than the older subjects. Repeated measurements of threshold over an interval as long as 1 month showed a standard deviation of 2.5 dB at the lower frequencies (8-14 kHz) and 4.5 dB at the higher frequencies.

  17. Multidimensional Clinical Phenotyping of an Adult Cystic Fibrosis Patient Population

    PubMed Central

    Conrad, Douglas J.; Bailey, Barbara A.

    2015-01-01

    Background Cystic Fibrosis (CF) is a multi-systemic disease resulting from mutations in the Cystic Fibrosis Transmembrane Regulator (CFTR) gene and has major manifestations in the sino-pulmonary, and gastro-intestinal tracts. Clinical phenotypes were generated using 26 common clinical variables to generate classes that overlapped quantiles of lung function and were based on multiple aspects of CF systemic disease. Methods The variables included age, gender, CFTR mutations, FEV1% predicted, FVC% predicted, height, weight, Brasfield chest xray score, pancreatic sufficiency status and clinical microbiology results. Complete datasets were compiled on 211 subjects. Phenotypes were identified using a proximity matrix generated by the unsupervised Random Forests algorithm and subsequent clustering by the Partitioning around Medoids (PAM) algorithm. The final phenotypic classes were then characterized and compared to a similar dataset obtained three years earlier. Findings Clinical phenotypes were identified using a clustering strategy that generated four and five phenotypes. Each strategy identified 1) a low lung health scores phenotype, 2) a younger, well-nourished, male-dominated class, 3) various high lung health score phenotypes that varied in terms of age, gender and nutritional status. This multidimensional clinical phenotyping strategy identified classes with expected microbiology results and low risk clinical phenotypes with pancreatic sufficiency. Interpretation This study demonstrated regional adult CF clinical phenotypes using non-parametric, continuous, ordinal and categorical data with a minimal amount of subjective data to identify clinically relevant phenotypes. These studies identified the relative stability of the phenotypes, demonstrated specific phenotypes consistent with published findings and identified others needing further study. PMID:25822311

  18. How systematic age underestimation can impede understanding of fish population dynamics: Lessons learned from a Lake Superior cisco stock

    USGS Publications Warehouse

    Yule, D.L.; Stockwell, J.D.; Black, J.A.; Cullis, K.I.; Cholwek, G.A.; Myers, J.T.

    2008-01-01

    Systematic underestimation of fish age can impede understanding of recruitment variability and adaptive strategies (like longevity) and can bias estimates of survivorship. We suspected that previous estimates of annual survival (S; range = 0.20-0.44) for Lake Superior ciscoes Coregonus artedi developed from scale ages were biased low. To test this hypothesis, we estimated the total instantaneous mortality rate of adult ciscoes from the Thunder Bay, Ontario, stock by use of cohort-based catch curves developed from commercial gill-net catches and otolith-aged fish. Mean S based on otolith ages was greater for adult females (0.80) than for adult males (0.75), but these differences were not significant. Applying the results of a study of agreement between scale and otolith ages, we modeled a scale age for each otolith-aged fish to reconstruct catch curves. Using modeled scale ages, estimates of S (0.42 for females, 0.36 for males) were comparable with those reported in past studies. We conducted a November 2005 acoustic and midwater trawl survey to estimate the abundance of ciscoes when the fish were being harvested for roe. Estimated exploitation rates were 0.085 for females and 0.025 for males, and the instantaneous rates of fishing mortality were 0.089 for females and 0.025 for males. The instantaneous rates of natural mortality were 0.131 and 0.265 for females and males, respectively. Using otolith ages, we found that strong year-classes at large during November 2005 were caught in high numbers as age-1 fish in previous annual bottom trawl surveys, whereas weak or absent year-classes were not. For decades, large-scale fisheries on the Great Lakes were allowed to operate because ciscoes were assumed to be short lived and to have regular recruitment. We postulate that the collapse of these fisheries was linked in part to a misunderstanding of cisco biology driven by scale-ageing error. ?? Copyright by the American Fisheries Society 2008.

  19. Computer program for sample sizes required to determine disease incidence in fish populations

    USGS Publications Warehouse

    Ossiander, Frank J.; Wedemeyer, Gary

    1973-01-01

    A computer program is described for generating the sample size tables required in fish hatchery disease inspection and certification. The program was designed to aid in detection of infectious pancreatic necrosis (IPN) in salmonids, but it is applicable to any fish disease inspection when the sampling plan follows the hypergeometric distribution.

  20. Distribution and abundance of fish populations in Harike wetland--a Ramsar site in India.

    PubMed

    Dua, Anish; Parkash, Chander

    2009-03-01

    Harike wetland was declared a Ramsar site in 1990. It is located at the confluence of two major rivers of Indus rivers system, the Beas and the Sutlej, but was never explored extensively for its existing fish biodiversity. Earlier only 27 fish species of commercial value were reported from the wetland. Acknowledging its importance for rich diversity fish assemblages in seven different reaches of Harike wetland were studied to determine their abundance and distribution. 61 fish species of 35 genera were recorded from Harike wetland during the present study. Cirrihinus mrigala and Cyprinus carpio belonging to family Cyprinidae were the dominant fish species. Lake and Riyasat having many microhabitats supported highest diversity of fishes (60 and 56 respectively) followed by Beas (20) Sutlej (14), Confluence (12), Reservoir (9) and Downstream (8). Among the IUCN designated threatened species, 1 Critically Endangered, 4 Endangered and 13 Vulnerable fish species of India are found in Harike wetland. Species diversity index, dominance, evenness and catch per unit effort were calculated to ascertain the fish distribution in Harike wetland.

  1. Fisheries-induced neutral and adaptive evolution in exploited fish populations and consequences for their adaptive potential

    PubMed Central

    Marty, Lise; Dieckmann, Ulf; Ernande, Bruno

    2015-01-01

    Fishing may induce neutral and adaptive evolution affecting life-history traits, and molecular evidence has shown that neutral genetic diversity has declined in some exploited populations. Here, we theoretically study the interplay between neutral and adaptive evolution caused by fishing. An individual-based eco-genetic model is devised that includes neutral and functional loci in a realistic ecological setting. In line with theoretical expectations, we find that fishing induces evolution towards slow growth, early maturation at small size and higher reproductive investment. We show, first, that the choice of genetic model (based on either quantitative genetics or gametic inheritance) influences the evolutionary recovery of traits after fishing ceases. Second, we analyse the influence of three factors possibly involved in the lack of evolutionary recovery: the strength of selection, the effect of genetic drift and the loss of adaptive potential. We find that evolutionary recovery is hampered by an association of weak selection differentials with reduced additive genetic variances. Third, the contribution of fisheries-induced selection to the erosion of functional genetic diversity clearly dominates that of genetic drift only for the traits related to maturation. Together, our results highlight the importance of taking into account population genetic variability in predictions of eco-evolutionary dynamics. PMID:25667602

  2. Fisheries-induced neutral and adaptive evolution in exploited fish populations and consequences for their adaptive potential.

    PubMed

    Marty, Lise; Dieckmann, Ulf; Ernande, Bruno

    2015-01-01

    Fishing may induce neutral and adaptive evolution affecting life-history traits, and molecular evidence has shown that neutral genetic diversity has declined in some exploited populations. Here, we theoretically study the interplay between neutral and adaptive evolution caused by fishing. An individual-based eco-genetic model is devised that includes neutral and functional loci in a realistic ecological setting. In line with theoretical expectations, we find that fishing induces evolution towards slow growth, early maturation at small size and higher reproductive investment. We show, first, that the choice of genetic model (based on either quantitative genetics or gametic inheritance) influences the evolutionary recovery of traits after fishing ceases. Second, we analyse the influence of three factors possibly involved in the lack of evolutionary recovery: the strength of selection, the effect of genetic drift and the loss of adaptive potential. We find that evolutionary recovery is hampered by an association of weak selection differentials with reduced additive genetic variances. Third, the contribution of fisheries-induced selection to the erosion of functional genetic diversity clearly dominates that of genetic drift only for the traits related to maturation. Together, our results highlight the importance of taking into account population genetic variability in predictions of eco-evolutionary dynamics.

  3. Components of the metabolic syndrome differ between young and old adults in the US population.

    PubMed

    Sumner, Andrew D; Sardi, Gabriel L; Reed, James F

    2012-08-01

    Prevalence of the metabolic syndrome (MetS) is high in the United States and is associated with increased risk of cardiovascular disease and diabetes. The authors examined whether the prevalence of the MetS and its components differs across age groups. Data were analyzed from 4 National Health and Nutrition Examination Surveys between the years 1999 and 2006. Prevalence of MetS as defined by the Third Report of the Adult Treatment Panel criteria and prevalence of associated cardiac risk factors were determined in 41,474 participants aged 18 years and older without a history of cardiovascular disease (CVD). All estimates were weighted. Prevalence of MetS among asymptomatic adults without CVD was 20.5% and remained stable for the total population during survey periods. Prevalence of MetS increased with age: 6.6% in young adults (age 18-29 years) and 34.6% in older adults (70 and older). Components of MetS differed between young and old adults. Young adults had lower levels of high-density lipoprotein cholesterol, less glucose intolerance, and less hypertension. This study provides an estimate of MetS prevalence in asymptomatic adults in the United States during an 8-year period revealing that MetS affects a large number of Americans. Components of MetS differ between young and old adults and may have important implications in their clinical management.

  4. Periodontal status in an urban adult population in Sweden.

    PubMed

    Söder, P O; Jin, L J; Söder, B; Wikner, S

    1994-04-01

    The purpose was to describe the current periodontal status in a Swedish urban population aged 31-40 yr. 1681 individuals, 840 men and 841 women, participated in the study. 68.5% of the subjects had low amount of plaque, 82.8% low level of calculus and 28.9% healthy gingiva or mild gingivitis. 82.8% of the subjects had no pockets with probing depth (PD) > or = 5 mm. 4.9% of the subjects had one tooth with PD > or = 5 mm, 6.7% 2-5 teeth, 2.4% 6-9 teeth and 3.2% > or = 10 teeth with pockets. 55.8% of the subjects had no missing teeth, third molars excluded. 16.5% had one tooth missing, 23.8% 2-5 teeth, 2.7% 6-9 teeth and 1.2% > or = 10 teeth. 8.6% of the subjects had at least one front tooth missing, 28.7% one premolar and 24.1% one molar missing. Men had significantly higher scores than women for plaque (DI-S), calculus (CI-S), gingivitis (GI-M), and number and percent of remaining teeth with PD > or = 5 mm. Smokers had significantly higher scores than non-smokers for DI-S, CI-S, GI-M, number and percent of remaining teeth with PD > or = 5 mm, and number of missing teeth. The individuals who visited the dentist every year had better oral hygiene and gingival status than those who attended for > 3 yr. The multiple regression analysis showed that calculus (P = 0.0001) smoking (P = 0.001), and dental visits (P = 0.0284) were significantly correlated to the number of teeth with PD > or = 5 mm.

  5. The Temporal Spectrum of Adult Mosquito Population Fluctuations: Conceptual and Modeling Implications

    PubMed Central

    Jian, Yun; Silvestri, Sonia; Brown, Jeff; Hickman, Rick; Marani, Marco

    2014-01-01

    An improved understanding of mosquito population dynamics under natural environmental forcing requires adequate field observations spanning the full range of temporal scales over which mosquito abundance fluctuates in natural conditions. Here we analyze a 9-year daily time series of uninterrupted observations of adult mosquito abundance for multiple mosquito species in North Carolina to identify characteristic scales of temporal variability, the processes generating them, and the representativeness of observations at different sampling resolutions. We focus in particular on Aedes vexans and Culiseta melanura and, using a combination of spectral analysis and modeling, we find significant population fluctuations with characteristic periodicity between 2 days and several years. Population dynamical modelling suggests that the observed fast fluctuations scales (2 days-weeks) are importantly affected by a varying mosquito activity in response to rapid changes in meteorological conditions, a process neglected in most representations of mosquito population dynamics. We further suggest that the range of time scales over which adult mosquito population variability takes place can be divided into three main parts. At small time scales (indicatively 2 days-1 month) observed population fluctuations are mainly driven by behavioral responses to rapid changes in weather conditions. At intermediate scales (1 to several month) environmentally-forced fluctuations in generation times, mortality rates, and density dependence determine the population characteristic response times. At longer scales (annual to multi-annual) mosquito populations follow seasonal and inter-annual environmental changes. We conclude that observations of adult mosquito populations should be based on a sub-weekly sampling frequency and that predictive models of mosquito abundance must include behavioral dynamics to separate the effects of a varying mosquito activity from actual changes in the abundance of the

  6. The temporal spectrum of adult mosquito population fluctuations: conceptual and modeling implications.

    PubMed

    Jian, Yun; Silvestri, Sonia; Brown, Jeff; Hickman, Rick; Marani, Marco

    2014-01-01

    An improved understanding of mosquito population dynamics under natural environmental forcing requires adequate field observations spanning the full range of temporal scales over which mosquito abundance fluctuates in natural conditions. Here we analyze a 9-year daily time series of uninterrupted observations of adult mosquito abundance for multiple mosquito species in North Carolina to identify characteristic scales of temporal variability, the processes generating them, and the representativeness of observations at different sampling resolutions. We focus in particular on Aedes vexans and Culiseta melanura and, using a combination of spectral analysis and modeling, we find significant population fluctuations with characteristic periodicity between 2 days and several years. Population dynamical modelling suggests that the observed fast fluctuations scales (2 days-weeks) are importantly affected by a varying mosquito activity in response to rapid changes in meteorological conditions, a process neglected in most representations of mosquito population dynamics. We further suggest that the range of time scales over which adult mosquito population variability takes place can be divided into three main parts. At small time scales (indicatively 2 days-1 month) observed population fluctuations are mainly driven by behavioral responses to rapid changes in weather conditions. At intermediate scales (1 to several month) environmentally-forced fluctuations in generation times, mortality rates, and density dependence determine the population characteristic response times. At longer scales (annual to multi-annual) mosquito populations follow seasonal and inter-annual environmental changes. We conclude that observations of adult mosquito populations should be based on a sub-weekly sampling frequency and that predictive models of mosquito abundance must include behavioral dynamics to separate the effects of a varying mosquito activity from actual changes in the abundance of the

  7. Breeding durations as estimators of adult sex ratios and population size.

    PubMed

    Payne, Nicholas Leslie; Gillanders, Bronwyn May; Semmens, Jayson

    2011-02-01

    Adult sex ratios (ASRs) and population size are two of the most fundamental parameters in population biology, as they are the main determinants of genetic and demographic viability, and vulnerability of a population to stochastic events. Underpinning the application of population viability analysis for predicting the extinction risk of populations is the need to accurately estimate parameters that determine the viability of populations (i.e. the ASR and population size). Here we demonstrate that a lack of temporal information can confound estimation of both parameters. Using acoustic telemetry, we compared differences in breeding durations of both sexes for a giant Australian cuttlefish Sepia apama breeding aggregation to the strongly male-biased operational sex ratio (4:1), in order to estimate the population ASR. The ratio of breeding durations between sexes was equal to the operational sex ratio, suggesting that the ASR is not strongly male-biased, but balanced. Furthermore, the short residence times of individuals at the breeding aggregation suggests that previous density-based abundance estimates have significantly underestimated population size. With the current wide application of population viability analysis for predicting the extinction risk of populations, tools to improve the accuracy of such predictions are vital. Here we provide a new approach to estimating the fundamental ASR parameter, and call for temporal considerations when estimating population size.

  8. An assessment of oil-spill effects on pink salmon populations following the Exxon Valdez oil spill. Part 2: Adults and escapement

    SciTech Connect

    Maki, A.W.; Brannon, E.J.; Gilbertson, L.G.; Moulton, L.L.; Skalski, J.R.

    1995-12-31

    This paper presents results of a field program designed to monitor the status of wildstock pink salmon populations in Prince William Sound following the Exxon Valdez oil spill. Field counts of spawning salmon were conducted each year from 1989 through 1992 to test for spill effects o the distribution nd abundance of pink salmon adults spawning in selected streams in the southwestern portion of Prince William Sound, including streams from the most heavily oiled areas. Counts of whole-stream and intertidal escapement density were statistically compared for 40 study streams in 1989 and for a subset of those streams in successive years. Measurements of residual hydrocarbons were made from stream-bed sediments to test for correlations with spawning behavior. Adult pink salmon in the postspill years of 1990 and 1991, progeny of the year classes considered most vulnerable to the oil spill, returned in high numbers, with the wildstock spawners exceeding their parent year returns. In 1989, adult returns reflected the relatively weak run for that year with a mean spawner density of 0.68 fish/m{sup 2} in reference streams and 0.69 fish/m{sup 2} in oiled streams. In 1990, mean escapement density for reference streams was 1.40 fish/m{sup 2} and 1.55 fish/m{sup 2} for oiled streams, indicating the strongest run of the four study years. Trends in polycyclic aromatic hydrocarbon (PAH) concentrations for the majority of oiled streams show a general decline from 1989 to background levels by 1990. 45 refs., 14 figs., 5 tabs.

  9. Associations among depressive symptoms, childhood abuse, neuroticism, and adult stressful life events in the general adult population

    PubMed Central

    Ono, Kotaro; Takaesu, Yoshikazu; Nakai, Yukiei; Shimura, Akiyoshi; Ono, Yasuyuki; Murakoshi, Akiko; Matsumoto, Yasunori; Tanabe, Hajime; Kusumi, Ichiro; Inoue, Takeshi

    2017-01-01

    Background Recent studies have suggested that the interactions among several factors affect the onset, progression, and prognosis of major depressive disorder. This study investigated how childhood abuse, neuroticism, and adult stressful life events interact with one another and affect depressive symptoms in the general adult population. Subjects and methods A total of 413 participants from the nonclinical general adult population completed the Patient Health Questionnaire-9, the Child Abuse and Trauma Scale, the neuroticism subscale of the shortened Eysenck Personality Questionnaire – Revised, and the Life Experiences Survey, which are self-report scales. Structural equation modeling (Mplus version 7.3) and single and multiple regressions were used to analyze the data. Results Childhood abuse, neuroticism, and negative evaluation of life events increased the severity of the depressive symptoms directly. Childhood abuse also indirectly increased the negative appraisal of life events and the severity of the depressive symptoms through enhanced neuroticism in the structural equation modeling. Limitations There was recall bias in this study. The causal relationship was not clear because this study was conducted using a cross-sectional design. Conclusion This study suggested that neuroticism is the mediating factor for the two effects of childhood abuse on adulthood depressive symptoms and negative evaluation of life events. Childhood abuse directly and indirectly predicted the severity of depressive symptoms. PMID:28243100

  10. Mercury levels and estimated total daily intakes for children and adults from an electronic waste recycling area in Taizhou, China: Key role of rice and fish consumption.

    PubMed

    Tang, Wei; Cheng, Jinping; Zhao, Wenchang; Wang, Wenhua

    2015-08-01

    In order to assess the potential health risks of Hg pollution, total mercury (T-Hg) and methyl mercury (MeHg) concentrations were determined in air, dust, surface soil, crops, poultry, fish and human hair samples from an electronic waste (e-waste) recycling area in Taizhou, China. High concentrations of T-Hg and MeHg were found in these multiple matrices, and the mean concentration was 30.7 ng/m(3) of T-Hg for atmosphere samples, 3.1 μg/g of T-Hg for soil, 37.6 μg/g of T-Hg for dust, 20.3 ng/g of MeHg for rice and 178.1 ng/g of MeHg for fish, suggesting that the e-waste recycling facility was a significant source of Hg. The inorganic Hg (I-Hg) levels (0.84 μg/g) in hair samples of e-waste workers were much higher than that in the reference samples. Pearson's correlation coefficients showed that strong positive correlations (p<0.01) between hair I-Hg and time staying in industrial area (r=0.81) and between MeHg and fish consumption frequency (r=0.91), imply that workers were mainly exposed to Hg vapor through long-time inhalation of contaminated air and dust, while other population mainly exposed to MeHg through high-frequency fish consumption. The estimated daily intakes of Hg showed that dietary intake was the major Hg exposure source, and Hg intakes from rice and fish were significantly higher than from any other foods. The estimated total daily intakes (TDIs) of MeHg for both children (696.8 ng/(kg·day)) and adults (381.3 ng/(kg·day)) greatly exceeded the dietary reference dose (RfD) of 230 ng/(kg·day), implying greater health risk for humans from Hg exposures around e-waste recycling facilities.

  11. Selective exploitation of large pike Esox lucius--effects on mercury concentrations in fish populations.

    PubMed

    Sharma, Chhatra Mani; Borgstrøm, Reidar; Huitfeldt, Jørgen Sinkaberg; Rosseland, Bjørn Olav

    2008-07-25

    The present study outlines two main trends of mercury transfer patterns through the fish community: 1) the Hg concentrations increase with increase in the trophic level, with top predators having the highest concentrations, and 2) a fast growth rate may dilute the concentrations of Hg in fish muscle tissue (growth biodilution). In 2004, an extensive reduction in number of large pike (Esox lucius L.), was initiated by selective gillnet fishing in Lake Arungen, Norway, in order to increase the pike recruitment due to an expected reduction in cannibalism. In this connection, total mercury (THg) concentrations in the fish community were studied both before (2003) and after (2005) the removal of large pike. The delta(15)N signatures and stomach content analyses indicated that pike and perch (Perca fluviatilis L.) occupied the highest trophic position, while roach (Rutilus rutilus (L.)) was at the lower level, and rudd (Scardinius erythrophthalmus L.) at the lowest. The piscivores, pike and perch, had the highest concentrations of THg. The biomagnification rate of THg through the food web in the fish community was 0.163 (per thousand delta(15)N), with the highest uptake rate (0.232) in perch. A significant decrease in THg concentrations was found in all fish species in 2005 compared to 2003. Removal of the top predators in an Hg contaminated lake might thus be an important management tool for reducing Hg levels in fish, thereby reducing health risk to humans.

  12. Multi-decadal responses of a cod (Gadus morhua) population to human-induced trophic changes, fishing, and climate.

    PubMed

    Eero, Margit; MacKenzie, Brian R; Köster, Friedrich W; Gislason, Henrik

    2011-01-01

    Understanding how human impacts have interacted with natural variability to affect populations and ecosystems is required for sustainable management and conservation. The Baltic Sea is one of the few large marine ecosystems worldwide where the relative contribution of several key forcings to changes in fish populations can be analyzed with empirical data. In this study we investigate how climate variability and multiple human impacts (fishing, marine mammal hunting, eutrophication) have affected multi-decadal scale dynamics of cod in the Baltic Sea during the 20th century. We document significant climate-driven variations in cod recruitment production at multi-annual timescales, which had major impacts on population dynamics and the yields to commercial fisheries. We also quantify the roles of marine mammal predation, eutrophication, and exploitation on the development of the cod population using simulation analyses, and show how the intensity of these forcings differed over time. In the early decades of the 20th century, marine mammal predation and nutrient availability were the main limiting factors; exploitation of cod was still relatively low. During the 1940s and subsequent decades, exploitation increased and became a dominant forcing on the population. Eutrophication had a relatively minor positive influence on cod biomass until the 1980s. The largest increase in cod biomass occurred during the late 1970s, following a long period of hydrographically related above-average cod productivity coupled to a temporary reduction in fishing pressure. The Baltic cod example demonstrates how combinations of different forcings can have synergistic effects and consequently dramatic impacts on population dynamics. Our results highlight the potential and limitations of human manipulations to influence predator species and show that sustainable management can only be achieved by considering both anthropogenic and naturally varying processes in a common framework.

  13. Variation in predation pressure as a mechanism underlying differences in numerical abundance between populations of the poeciliid fish Heterandria formosa

    USGS Publications Warehouse

    Richardson, J.M.L.; Gunzburger, M.S.; Travis, J.

    2006-01-01

    We explored whether a variation in predation and habitat complexity between conspecific populations can drive qualitatively different numerical dynamics in those populations. We considered two disjunct populations of the least killifish, Heterandria formosa, that exhibit long-term differences in density, top fish predator species, and dominant aquatic vegetation. Monthly censuses over a 3-year period found that in the higher density population, changes in H. formosa density exhibited a strong negative autocorrelation structure: increases (decreases) at one census tended to be followed by decreases (increases) at the next one. However, no such correlation was present in the lower density population. Monthly census data also revealed that predators, especially Lepomis sp., were considerably more abundant at the site with lower H. formosa densities. Experimental studies showed that the predation by Lepomis gulosus occurred at a much higher rate than predation by two other fish and two dragonfly species, although L. gulosus and L. punctatus had similar predation rates when the amount of vegetative cover was high. The most effective predator, L. gulosus, did not discriminate among life stages (males, females, and juveniles) of H. formosa. Increased predation rates by L. gulosus could keep H. formosa low in one population, thereby eliminating strong negative density-dependent regulation. In support of this, changes in H. formosa density were positively correlated with changes in vegetative cover for the population with a history of lower density, but not for the population with a history of higher density. Our results are consistent with the hypothesis that the observed differences among natural populations in numerical abundance and dynamics are caused in part by the differences in habitat complexity and the predator community. ?? Springer-Verlag 2005.

  14. Population-Based Surveillance for Invasive Pneumococcal Disease in Homeless Adults in Toronto

    PubMed Central

    Plevneshi, Agron; Svoboda, Tomislav; Armstrong, Irene; Tyrrell, Gregory J.; Miranda, Anna; Green, Karen; Low, Donald; McGeer, Allison

    2009-01-01

    Background Identification of high-risk populations for serious infection due to S. pneumoniae will permit appropriately targeted prevention programs. Methods We conducted prospective, population-based surveillance for invasive pneumococcal disease and laboratory confirmed pneumococcal pneumonia in homeless adults in Toronto, a Canadian city with a total population of 2.5 M, from January 1, 2002 to December 31, 2006. Results We identified 69 cases of invasive pneumococcal disease and 27 cases of laboratory confirmed pneumococcal pneumonia in an estimated population of 5050 homeless adults. The incidence of invasive pneumococcal disease in homeless adults was 273 infections per 100,000 persons per year, compared to 9 per 100,000 persons per year in the general adult population. Homeless persons with invasive pneumococcal disease were younger than other adults (median age 46 years vs 67 years, P<.001), and more likely than other adults to be smokers (95% vs. 31%, P<.001), to abuse alcohol (62% vs 15%, P<.001), and to use intravenous drugs (42% vs 4%, P<.001). Relative to age matched controls, they were more likely to have underlying lung disease (12/69, 17% vs 17/272, 6%, P = .006), but not more likely to be HIV infected (17/69, 25% vs 58/282, 21%, P = .73). The proportion of patients with recurrent disease was five fold higher for homeless than other adults (7/58, 12% vs. 24/943, 2.5%, P<.001). In homeless adults, 28 (32%) of pneumococcal isolates were of serotypes included in the 7-valent conjugate vaccine, 42 (48%) of serotypes included in the 13-valent conjugate vaccine, and 72 (83%) of serotypes included in the 23-valent polysaccharide vaccine. Although no outbreaks of disease were identified in shelters, there was evidence of clustering of serotypes suggestive of transmission of pathogenic strains within the homeless population. Conclusions Homeless persons are at high risk of serious pneumococcal infection. Vaccination, physical structure changes or

  15. HIV/AIDS Misconceptions among Latinos: Findings from a Population-Based Survey of California Adults

    ERIC Educational Resources Information Center

    Ritieni, Assunta; Moskowitz, Joel; Tholandi, Maya

    2008-01-01

    Misconceptions about HIV/AIDS among Latino adults (N=454) in California were examined using data from a population-based telephone survey conducted in 2000. Common misconceptions concerning modes of HIV transmission included transmission via mosquito or animal bite (64.1%), public facilities (48.3%), or kissing someone on the cheek (24.8%). A…

  16. Eysenck Personality Inventory: A Normative Study on an Adult Industrial Population.

    ERIC Educational Resources Information Center

    Hester, Reid K.; Brown, William R.

    1980-01-01

    Developed norms for an adult industrial population for the Eysenck Personality Inventory. An analysis of scale scores by age, sex, marital status, and occupational category revealed significant differences in extraversion scale scores by age and sex. Norm tables are presented by sex. (Author)

  17. The Contributions of Phonological and Morphological Awareness to Literacy Skills in the Adult Basic Education Population

    ERIC Educational Resources Information Center

    Fracasso, Lucille E.; Bangs, Kathryn; Binder, Katherine S.

    2016-01-01

    The Adult Basic Education (ABE) population consists of a wide range of abilities with needs that may be unique to this set of learners. The purpose of this study was to better understand the relative contributions of phonological decoding and morphological awareness to spelling, vocabulary, and comprehension across a sample of ABE students. In…

  18. "Subtypes" in the Presentation of Autistic Traits in the General Adult Population

    ERIC Educational Resources Information Center

    Palmer, Colin J.; Paton, Bryan; Enticott, Peter G.; Hohwy, Jakob

    2015-01-01

    The present study examined the presentation of autistic traits in a large adult population sample (n = 2,343). Cluster analysis indicated two subgroups with clearly distinguishable trait profiles. One group (n = 1,059) reported greater social difficulties and lower detail orientation, while the second group (n = 1,284) reported lesser social…

  19. A Meta-Analysis of Dunn and Dunn Model Correlational Research with Adult Populations

    ERIC Educational Resources Information Center

    Mangino, Christine

    2004-01-01

    The purpose of this investigation was to conduct a quantitative synthesis of correlational research that focused on the Dunn and Dunn Learning-Style Model and was concerned with adult populations. A total of 8,661 participants from the 47 original investigations provided 386 individual effect sizes for this meta-analysis. The mean effect size was…

  20. Meeting the Needs of Older Adult Refugee Populations With Home Health Services.

    PubMed

    Miner, Sarah M; Liebel, Dianne; Wilde, Mary H; Carroll, Jennifer K; Zicari, Elizabeth; Chalupa, Stephanie

    2015-12-27

    The United States resettles close to 70,000 refugees each year more than any other country in the world. Adult refugees are at risk for negative health outcomes and inefficient health resource use, and meeting the multiple health needs of this vulnerable population is a challenge. The purpose of this study was to assess the impact of a home health care (HHC) pilot project on meeting the needs of older adult refugee patients. A retrospective chart review of 40 refugee adult patients who participated in an HHC pilot was done to analyze their health outcomes using OASIS-C data. Participants' pain level, anxiety level, medication management, and activities of daily living management all significantly improved over the course of their HHC episode. Results of this study indicate that HHC has great potential to improve the health of vulnerable refugee populations and assist the families involved in their care.

  1. Fish oil–derived n–3 PUFA therapy increases muscle mass and function in healthy older adults1

    PubMed Central

    Smith, Gordon I; Julliand, Sophie; Reeds, Dominic N; Sinacore, David R; Klein, Samuel; Mittendorfer, Bettina

    2015-01-01

    Background: Age-associated declines in muscle mass and function are major risk factors for an impaired ability to carry out activities of daily living, falls, prolonged recovery time after hospitalization, and mortality in older adults. New strategies that can slow the age-related loss of muscle mass and function are needed to help older adults maintain adequate performance status to reduce these risks and maintain independence. Objective: We evaluated the efficacy of fish oil–derived n–3 (ω-3) PUFA therapy to slow the age-associated loss of muscle mass and function. Design: Sixty healthy 60–85-y-old men and women were randomly assigned to receive n–3 PUFA (n = 40) or corn oil (n = 20) therapy for 6 mo. Thigh muscle volume, handgrip strength, one-repetition maximum (1-RM) lower- and upper-body strength, and average power during isokinetic leg exercises were evaluated before and after treatment. Results: Forty-four subjects completed the study [29 subjects (73%) in the n–3 PUFA group; 15 subjects (75%) in the control group]. Compared with the control group, 6 mo of n–3 PUFA therapy increased thigh muscle volume (3.6%; 95% CI: 0.2%, 7.0%), handgrip strength (2.3 kg; 95% CI: 0.8, 3.7 kg), and 1-RM muscle strength (4.0%; 95% CI: 0.8%, 7.3%) (all P < 0.05) and tended to increase average isokinetic power (5.6%; 95% CI: −0.6%, 11.7%; P = 0.075). Conclusion: Fish oil–derived n–3 PUFA therapy slows the normal decline in muscle mass and function in older adults and should be considered a therapeutic approach for preventing sarcopenia and maintaining physical independence in older adults. This study was registered at clinicaltrials.gov as NCT01308957. PMID:25994567

  2. Modeling responses of large-river fish populations to global climate change through downscaling and incorporation of predictive uncertainty

    USGS Publications Warehouse

    Wildhaber, Mark L.; Wikle, Christopher K.; Anderson, Christopher J.; Franz, Kristie J.; Moran, Edward H.; Dey, Rima; Mader, Helmut; Kraml, Julia

    2012-01-01

    Climate change operates over a broad range of spatial and temporal scales. Understanding its effects on ecosystems requires multi-scale models. For understanding effects on fish populations of riverine ecosystems, climate predicted by coarse-resolution Global Climate Models must be downscaled to Regional Climate Models to watersheds to river hydrology to population response. An additional challenge is quantifying sources of uncertainty given the highly nonlinear nature of interactions between climate variables and community level processes. We present a modeling approach for understanding and accomodating uncertainty by applying multi-scale climate models and a hierarchical Bayesian modeling framework to Midwest fish population dynamics and by linking models for system components together by formal rules of probability. The proposed hierarchical modeling approach will account for sources of uncertainty in forecasts of community or population response. The goal is to evaluate the potential distributional changes in an ecological system, given distributional changes implied by a series of linked climate and system models under various emissions/use scenarios. This understanding will aid evaluation of management options for coping with global climate change. In our initial analyses, we found that predicted pallid sturgeon population responses were dependent on the climate scenario considered.

  3. Old fish in a young lake: stone loach (Pisces: Barbatula barbatula) populations in Lake Constance are genetically isolated by distance.

    PubMed

    Barluenga, Marta; Meyer, Axel

    2005-04-01

    The genetic structure of 10 populations (453 individuals) of stone loach (Barbatula barbatula L.), a small bottom-dwelling cyprinid fish, in the littoral zone of Lake Constance, central Europe, was investigated by analysing the mitochondrial control region sequences and five microsatellite loci. An unexpectedly high degree of genetic diversity (up to 0.36%) and old estimated age of these populations (> 150 000 years) based on mitochondrial DNA (mtDNA) was found. These findings contrast with the relatively young age of the lake, which could be colonized by fish only after the last ice age around 15 000 bp. Stone loach appears to be an old species in a young lake. Both types of molecular markers showed population genetic structure pronounced in mtDNA (overall F(ST) = 0.15) but moderate in microsatellites (F(ST) = 0.03). As predicted by its life history, philopatry, and limited capacity for dispersal, stone loach populations of Lake Constance show a clear pattern of isolation by distance. Geographic distances along the shores are the best explanation for the observed geographical distribution of genetic differentiation (r = 0.88), indicating that open water represents a barrier for the dispersal of the stone loach. The colonization of Lake Constance might have occurred initially at one location and then populations spread throughout the lake in a stepwise manner following the shoreline, and subsequently remained largely genetically isolated as suggested by the large observed differences among them.

  4. Pathogens associated with native and exotic trout populations in Shenandoah National Park and the relationships to fish stocking practices

    USGS Publications Warehouse

    Panek, Frank M.; Atkinson, James; Coll, John

    2008-01-01

    Restrictive fish stocking policies in National Parks were developed as early as 1936 in order to preserve native fish assemblages and historic genetic diversity. Despite recent efforts to understand the effects of non-native or exotic fish introductions, park managers have limited information regarding the effects of these introductions on native fish communities. Shenandoah National Park was established in 1936 and brook trout (Salvelinus fontinalis) restoration within selected streams in the park began in 1937 in collaboration with the Virginia Department of Game and Inland Fisheries (VDGIF). An analysis of tissue samples from brook, brown (Salmo trutta), and rainbow trout (Oncorhynchus mykiss) from 29 streams within the park from 1998–2002 revealed the presence of Renibacterium salmoninarum, Yersinia ruckeri, and infectious pancreatic necrosis virus (IPNv). In order to investigate the relationships of the occurrence of fish pathogens with stocking histories we classified the streams into three categories: 1) streams with no record of stocking, 2) streams that are known to have been stocked historically, and 3) streams that were historically stocked within the park and continue to be stocked downstream of the park boundary. The occurrences of pathogens were summarized relative to this stocking history. Renibacterium salmoninarum, the causative agent of bacterial kidney disease, was the most prevalent pathogen found, occurring in all three species and stream stocking categories, and appears to be endemic to the park. Two other pathogens, Yersinia ruckeri and infectious pancreatic necrosis virus were also described from brook trout populations within the park. IPNv was only found in brook trout populations in streams with prior stocking histories. Yersinia ruckeri was only found in brook trout in steams that have never been stocked and like R. salmoninarum, is likely endemic.

  5. EFFECTS OF SEASONAL AND WATER QUALITY PARAMETERS ON OYSTERS (CRASSOSTREA VIRGINICA) AND ASSOCIATED FISH POPULATIONS.

    EPA Science Inventory

    Influence of water quality and seasonal changes on disease prevalence and intensity of Perkinsus marinus, gonadal condition, recruitment potential, growth of caged juvenile oysters, and habitat suitability of reefs for fishes and macrobenthic invertebrates were measured in Callos...

  6. Long-term sedative use among community-dwelling adults: a population-based analysis

    PubMed Central

    Weymann, Deirdre; Gladstone, Emilie J.; Smolina, Kate; Morgan, Steven G.

    2017-01-01

    Background: Chronic use of benzodiazepines and benzodiazepine-like sedatives (z-drugs) presents substantial risks to people of all ages. We sought to assess trends in long-term sedative use among community-dwelling adults in British Columbia. Methods: Using population-based linked administrative databases, we examined longitudinal trends in age-standardized rates of sedative use among different age groups of community-dwelling adults (age ≥ 18 yr), from 2004 to 2013. For each calendar year, we classified adults as nonusers, short-term users, or long-term users of sedatives based on their patterns of sedative dispensation. For calendar year 2013, we applied cross-sectional analysis and estimated logistic regression models to identify health and socioeconomic risk factors associated with long-term sedative use. Results: More than half (53.4%) of long-term users of sedatives in British Columbia are between ages 18 and 64 years (young and middle-aged adults). From 2004 to 2013, long-term sedative use remained stable among adults more than 65 years of age (older adults) and increased slightly among young and middle-aged adults. Although the use of benzodiazepines decreased during the study period, the trend was offset by equal or greater increases in long-term use of z-drugs. Being an older adult, sick, poor and single were associated with increased odds of long-term sedative use. Interpretation: Despite efforts to stem such patterns of medication use, long-term use of sedatives increased in British Columbia between 2004 and 2013. This increase was driven largely by increased use among middle-aged adults. Future deprescribing efforts that target adults of all ages may help curb this trend.

  7. Reduced Spill at Hydropower Dams: Opportunities for More Generation and Increased Fish Population

    SciTech Connect

    Coutant, Charles C; Mann, Roger; Sale, Michael J

    2006-09-01

    This report indicates that reduction of managed spill at hydropower dams can speed implementation of technologies for fish protection and achieve economic goals. Spill of water over spillways is managed in the Columbia River basin to assist downstream-migrating juvenile salmon, and is generally believed to be the most similar to natural migration, benign and effective passage route; other routes include turbines, intake screens with bypasses, and surface bypasses. However, this belief may be misguided, because spill is becoming recognized as less than natural, with deep intakes below normal migration depths, and likely causing physical damages from severe shear on spillways, high turbulence in tail waters, and collisions with baffle blocks that lead to disorientation and predation. Some spillways induce mortalities comparable to turbines. Spill is expensive in lost generation, and controversial. Fish-passage research is leading to more fish-friendly turbines, screens and bypasses that are more effective and less damaging, and surface bypasses that offer passage of more fish per unit water volume than does spill (leaving more water for generation). Analyses by independent economists demonstrated that goals of increased fish survival over the long term and net gain to the economy can be obtained by selectively reducing spill and diverting some of the income from added power generation to research, development, and installation of fish-passage technologies. Such a plan would selectively reduce spill when and where least damaging to fish, increase electricity generation using the water not spilled and use innovative financing to direct monetary gains to improving fish passage.

  8. A Novel Technique to Detect Epipelagic Fish Populations and Map their Habitat

    DTIC Science & Technology

    2009-09-30

    throughout the water column both vertically and horizontally. So, to assess the total availability of plankton prey to foraging sardines, acoustic...available to fish predators during nighttime foraging hours (Figure 4). The opposite pattern of prey availability was observed in Monterey Bay, with the...influence of prey abundance was investigated to determine what impact prey availability has on fish schooling behavior. This information will be used

  9. Mercury in southeastern U.S. riverine fish populations linked to water body type.

    PubMed

    Rypel, Andrew L; Arrington, D Albrey; Findlay, Robert H

    2008-07-15

    We compared Hg concentrations in fishes from the regulated Black Warrior River and the unregulated Sipsey River in west Alabama whose neighboring watersheds receive equivalent atmospheric Hg deposition. Average fish fillet Hg concentrations were 3-fold higher in the unregulated river compared to the regulated river. Between river differences in Hg fish concentrations likely originate from structural (e.g., species composition) and functional (e.g., energy flow pathways) differences between the two ecosystems. We tested the generality of these findings by comparing largemouth bass Hg concentrations among unregulated rivers (n=6) and reservoirs (n=11) throughout the southern Coastal Plain geologic region. ANCOVA revealed that at a given bass length, Hg concentrations were approximately 1.75 times higher in unregulated rivers compared to regulated rivers. Aerial deposition of Hg was not correlated to largemouth bass Hg concentrations. We suggest that the link between atmospheric Hg deposition and fish Hg concentrations is significantly modulated by the structure and function of aquatic ecosystems and this accounts for much of the variation in fish Hg concentrations among systems. Unregulated floodplain-rivers in the south have some of the highest fish Hg concentrations on record and should be intensely monitored to establish human consumption risks.

  10. Influence of Habitat Modifications on Habitat Composition and Anadromous Salmonid Populations in Fish Creek, Oregon, 1983-1988 Annual Report.

    SciTech Connect

    Reeves, Gordon H.; Everest, Fred H.; Hohler, David B.

    1990-05-01

    Modification of degraded habitats to increase populations of anadromous salmonids is a major focus of management agencies throughout the Pacific Northwest. Millions of dollars are spent annually on such efforts. Inherent in implementing habitat improvements is the need for quantitative evaluation of the biological and physical effects of such work. Reeves et al. (in press), however, noted that such evaluations are rare, making it difficult to assess the true results of habitat work. While it is not economically possible to thoroughly evaluate every habitat project, it is essential that intensive evaluations be done on selected representative projects. One such evaluation program has been underway since 1982 on Fish Creek, a tributary of the Clackamas River near Estacada, OR. Habitat modification has been done by the USDA Forest Service, Estacada Ranger District, Mt. Hood National Forest with funding provided in part by the Bonneville Power Administration (BPA). The USDA Forest Service, Anadromous Fish Habitat Research Unit, Pacific Northwest Research Station (PNW), Corvallis, OR is charged with: (1) evaluating the biological and physical responses to habitat modifications on a basin scale; and (2) developing a cost-benefit analysis of the program. Preliminary results have been reported in a series of annual publications, Everest and Sedell 1983, 1984 and Everest et al. 1985, 1986, 1987, 1988. The objectives of this paper are to: (1) report 1988 observations of biological and physical changes in habitat, salmonid populations, and smolt production in Fish Creek, and (2) examine preliminary trends in fish habitat and populations related to habitat improvement over the period 1983-1988. We have prefaced the trends in the latter objective as preliminary because we believe it could take a minimum of 10 years before the full biological and physical responses to habitat work are realized. We therefore urge caution in interpreting these preliminary results.

  11. Population-structure and genetic diversity in a haplochromine cichlid fish [corrected] of a satellite lake of Lake Victoria.

    PubMed

    Abila, Romulus; Barluenga, Marta; Engelken, Johannes; Meyer, Axel; Salzburger, Walter

    2004-09-01

    The approximately 500 species of the cichlid fish species flock of Lake Victoria, East Africa, have evolved in a record-setting 100,000 years and represent one of the largest adaptive radiations. We examined the population structure of the endangered cichlid species Xystichromis phytophagus from Lake Kanyaboli, a satellite lake to Lake Victoria in the Kenyan Yala wetlands. Two sets of molecular markers were analysed--sequences of the mitochondrial control region as well as six microsatellite loci--and revealed surprisingly high levels of genetic variability in this species. Mitochondrial DNA sequences failed to detect population structuring among the three sample populations. A model-based population assignment test based on microsatellite data revealed that the three populations most probably aggregate into a larger panmictic population. However, values of population pairwise FST indicated moderate levels of genetic differentiation for one population. Eleven distinct mitochondrial haplotypes were found among 205 specimens of X. phytophagus, a relatively high number compared to the total number of 54 haplotypes that were recovered from hundreds of specimens of the entire cichlid species flock of Lake Victoria. Most of the X. phytophagus mitochondrial DNA haplotypes were absent from the main Lake Victoria, corroborating the putative importance of satellite lakes as refugia for haplochromine cichlids that went extinct from the main lake in the last decades and possibly during the Late Pleistocene desiccation of Lake Victoria.

  12. Body Mass Index in Adults with Intellectual Disability: Distribution, Associations and Service Implications--A Population-Based Prevalence Study

    ERIC Educational Resources Information Center

    Bhaumik, S.; Watson, J. M.; Thorp, C. F.; Tyrer, F.; McGrother, C. W.

    2008-01-01

    Background: Previous studies of weight problems in adults with intellectual disability (ID) have generally been small or selective and given conflicting results. The objectives of our large-scale study were to identify inequalities in weight problems between adults with ID and the general adult population, and to investigate factors associated…

  13. Normative data and discriminant validity of Rey's Verbal Learning Test for the Greek adult population.

    PubMed

    Messinis, Lambros; Tsakona, Ioanna; Malefaki, Sonia; Papathanasopoulos, Panagiotis

    2007-08-01

    The present study sought to establish normative and discriminant validity data for Rey's Auditory Verbal Learning Test [Rey, A. (1964). L 'examen clinique en psychologie [Clinical tests in psychology]. Paris: Presses Universitaires de France; Schmidt, M. (1996). Rey auditory verbal learning test: A handbook. Los Angeles, CA: Western Psychological Services] using newly adapted learning lists for the Greek adult population. Applying the procedure suggested by Geffen et al. [Geffen, G., Moar, K. J., O'Hanlon, A. P., Clark, C. R., & Geffen, L. N. (1990). Performance measures of 16-86-year-old males and females on the auditory verbal learning test. The Clinical Neuropsychologist, 4, 45-63] we administered the test to 205 healthy participants, aged 18-78 years and two adult patient groups (long-term cannabis users and HIV symptomatic patients). Stepwise linear regression analyses showed that the variables age, education and gender contributed significantly to most trials of the RAVLT. Performance decreased in an age-dependent manner from young adulthood. Women, young adults and higher educated participants outperformed men, older adults and less educated individuals. The test appears to discriminate adequately between the performance of long-term heavy cannabis users and HIV seropositive symptomatic patients and matched healthy controls, as both patient groups performed more poorly than their respective control group. Normative data stratified by age, gender and education for the Greek adult population is presented for use in research and clinical settings.

  14. Mercury exposure in a high fish eating Bolivian Amazonian population with intense small-scale gold-mining activities.

    PubMed

    Barbieri, Flavia Laura; Cournil, Amandine; Gardon, Jacques

    2009-08-01

    Methylmercury exposure in Amazonian communities through fish consumption has been widely documented in Brazil. There is still a lack of data in other Amazonian countries, which is why we conducted this study in the Bolivian Amazon basin. Simple random sampling was used from a small village located in the lower Beni River, where there is intense gold mining and high fish consumption. All participants were interviewed and hair samples were taken to measure total mercury concentrations. The hair mercury geometric mean in the general population was 3.02 microg/g (CI: 2.69-3.37; range: 0.42-15.65). Age and gender were not directly associated with mercury levels. Fish consumption showed a positive relation and so did occupation, especially small-scale gold mining. Hair mercury levels were lower than those found in Brazilian studies, but still higher than in non-exposed populations. It is necessary to assess mercury exposure in the Amazonian regions where data is still lacking, using a standardized indicator.

  15. Fish community changes in the St. Louis River estuary, Lake Superior, 1989-1996: Is it ruffe or population dynamics?

    USGS Publications Warehouse

    Bronte, Charles R.; Evrard, Lori M.; Brown, William P.; Mayo, Kathleen R.; Edwards, Andrew J.

    1998-01-01

    Ruffe (Gymnocephalus cernuus) have been implicated in density declines of native species through egg predation and competition for food in some European waters where they were introduced. Density estimates for ruffe and principal native fishes in the St. Louis River estuary (western Lake Superior) were developed for 1989 to 1996 to measure changes in the fish community in response to an unintentional introduction of ruffe. During the study, ruffe density increased and the densities of several native species decreased. The reductions of native stocks to the natural population dynamics of the same species from Chequamegon Bay, Lake Superior (an area with very few ruffe) were developed, where there was a 24-year record of density. Using these data, short- and long-term variations in catch and correlations among species within years were compared, and species-specific distributions were developed of observed trends in abundance of native fishes in Chequamegon Bay indexed by the slopes of densities across years. From these distributions and our observed trend-line slopes from the St. Louis River, probabilities of measuring negative change at the magnitude observed in the St. Louis River were estimated. Compared with trends in Chequamegon Bay, there was a high probability of obtaining the negative slopes measured for most species, which suggests natural population dynamics could explain, the declines rather than interactions with ruffe. Variable recruitment, which was not related to ruffe density, and associated density-dependent changes in mortality likely were responsible for density declines of native species.

  16. Population Models for Stream Fish Response to Habitat and Hydrologic Alteration: the CVI Watershed Tool. EPA/600/R-04/190

    EPA Pesticide Factsheets

    Models that predict the responses of fish populations and communities to key habitat characteristics are necessary for CVIs watershed management goals, for determining where to restore and how, as well as evaluating the most probable outcome.

  17. AHR-related activities in a creosote-adapted population of adult atlantic killifish, Fundulus heteroclitus, two decades post-EPA superfund status at the Atlantic Wood Site, Portsmouth, VA USA.

    PubMed

    Wojdylo, Josephine V; Vogelbein, Wolfgang; Bain, Lisa J; Rice, Charles D

    2016-08-01

    Atlantic killifish, Fundulus heteroclitus, are adapted to creosote-based PAHs at the US EPA Superfund site known as Atlantic Wood (AW) on the southern branch of the Elizabeth River, VA USA. Subsequent to the discovery of the AW population in the early 1990s, these fish were shown to be recalcitrant to CYP1A induction by PAHs under experimental conditions, and even to the time of this study, killifish embryos collected from the AW site are resistant to developmental deformities typically associated with exposure to PAHs in reference fish. Historically, however, 90 +% of the adult killifish at this site have proliferative hepatic lesions including cancer of varying severity. Several PAHs at this site are known to be ligands for the aryl hydrocarbon receptor (AHR). In this study, AHR-related activities in AW fish collected between 2011 and 2013 were re-examined nearly 2 decades after first discovery. This study shows that CYP1A mRNA expression is three-fold higher in intestines of AW killifish compared to a reference population. Using immunohistochemistry, CYP1A staining in intestines was uniformly positive compared to negative staining in reference fish. Livers of AW killifish were examined by IHC to show that CYP1A and AHR2 protein expression reflect lesions-specific patterns, probably representing differences in intrinsic cellular physiology of the spectrum of proliferative lesions comprising the hepatocarcinogenic process. We also found that COX2 mRNA expression levels were higher in AW fish livers compared to those in the reference population, suggesting a state of chronic inflammation. Overall, these findings suggest that adult AW fish are responsive to AHR signaling, and do express CYP1A and AHR2 proteins in intestines at a level above what was observed in the reference population.

  18. Episodic acidification of small streams in the northeastern united states: Effects on fish populations

    USGS Publications Warehouse

    Baker, J.P.; Van Sickle, J.; Gagen, C.J.; DeWalle, David R.; Sharpe, W.E.; Carline, R.F.; Baldigo, Barry P.; Murdoch, Peter S.; Bath, D.W.; Kretser, W.A.; Simonin, H.A.; Wigington, P.J.

    1996-01-01

    As part of the Episodic Response Project (ERP), we studied the effects of episodic acidification on fish in 13 small streams in the northeastern United States: four streams in the Adirondack region of New York, four streams in the Catskills, New York, and five streams in the northern Appalachian Plateau, Pennsylvania. In situ bioassays with brook trout (Salvelinus fontinalis) and a forage fish species (blacknose dace (Rhinichthys atratulus], mottled sculpin (Cottus bairdi), or slimy sculpin (Cottus cognatus), depending on the region) measured direct toxicity. Movements of individual brook trout, in relation to stream chemistry, were monitored using radiotelemetry. Electrofishing surveys assessed fish community status and the density and biomass of brook trout in each stream. During low flow, all streams except one had chemical conditions considered suitable for the survival and reproduction of most fish species (median pH 6.0-7.2 during low flow; inorganic Al 100-200 ??g/L. We conclude that episodic acidification can have long-term effects on fish communities in small streams.

  19. How many steps/day are enough? For older adults and special populations

    PubMed Central

    2011-01-01

    Older adults and special populations (living with disability and/or chronic illness that may limit mobility and/or physical endurance) can benefit from practicing a more physically active lifestyle, typically by increasing ambulatory activity. Step counting devices (accelerometers and pedometers) offer an opportunity to monitor daily ambulatory activity; however, an appropriate translation of public health guidelines in terms of steps/day is unknown. Therefore this review was conducted to translate public health recommendations in terms of steps/day. Normative data indicates that 1) healthy older adults average 2,000-9,000 steps/day, and 2) special populations average 1,200-8,800 steps/day. Pedometer-based interventions in older adults and special populations elicit a weighted increase of approximately 775 steps/day (or an effect size of 0.26) and 2,215 steps/day (or an effect size of 0.67), respectively. There is no evidence to inform a moderate intensity cadence (i.e., steps/minute) in older adults at this time. However, using the adult cadence of 100 steps/minute to demark the lower end of an absolutely-defined moderate intensity (i.e., 3 METs), and multiplying this by 30 minutes produces a reasonable heuristic (i.e., guiding) value of 3,000 steps. However, this cadence may be unattainable in some frail/diseased populations. Regardless, to truly translate public health guidelines, these steps should be taken over and above activities performed in the course of daily living, be of at least moderate intensity accumulated in minimally 10 minute bouts, and add up to at least 150 minutes over the week. Considering a daily background of 5,000 steps/day (which may actually be too high for some older adults and/or special populations), a computed translation approximates 8,000 steps on days that include a target of achieving 30 minutes of moderate-to-vigorous physical activity (MVPA), and approximately 7,100 steps/day if averaged over a week. Measured directly and

  20. Health and wellbeing of Victorian adults with intellectual disability compared to the general Victorian population.

    PubMed

    Haider, Syed Imran; Ansari, Zahid; Vaughan, Loretta; Matters, Helen; Emerson, Eric

    2013-11-01

    Multiple measures of health and wellbeing of people with intellectual disability (ID) and the general Victorian population were compared using representative population level data. The sample consisted of adults with ID (N=897) and the general Victorian population (N=34,168) living in the state of Victoria in Australia. Proxy respondents were interviewed on behalf of people with ID, while respondents from the general Victorian population were interviewed directly. The data were weighted to reflect the age/sex/geographic distribution of the population. Results revealed that adults with ID reported higher prevalence of poor social determinants of health, behavioural risk factors, depression, diabetes, poor or fair health. A higher proportion of people with ID reported blood pressure and blood glucose checks, while a lower proportion reported cervical and breast cancer screening, compared with the general Victorian population. The survey identified areas where targeted approaches may be undertaken to improve the health outcomes of people with ID and provide an important understanding of the health and wellbeing of these Victorians.

  1. [Obesity in adults: a population based study in a small town in South of Brazil, 2005].

    PubMed

    Sarturi, Juliana Barbosa; das Neves, Janaina; Peres, Karen Glazer

    2010-01-01

    Changes in nutritional pattern in Brazilian population have been observed mainly in relation to obesity increase. This study aims to estimate the prevalence of obesity and associated factors in adult population in Santo Angelo, Rio Grande do Sul State, 2005. A cross sectional study was carried out involving adult subjects from 20 to 59 years old (n=434), of both sexes. People with Body Mass Index equal to or higher than 30 kg/m(2) were considered obese. A questionnaire was applied to collect data related to socioeconomic, demographic, and behavioral conditions. The multiple logistic regression analysis was performed to identify the associated factors. The response rate was 95.0% and the prevalence of obesity was equal to 16.6% (CI 95% 13.120.1). Presence of obesity was positively associated with lack of physical activity, none feeding habits care, and some individuals that mentioned current health problems regardless of sex. The prevalence of obesity found was similar to other Brazilian population based studies. The results may support planning and implementing prevention actions as well as obesity control in adult population taking into account the relevant details of a small size town.

  2. Acculturation stress, anxiety disorders, and alcohol dependence in a select population of young adult Mexican Americans

    PubMed Central

    Ehlers, Cindy L.; Gilder, David A.; Criado, Jose R.; Caetano, Raul

    2009-01-01

    Objectives Mexican Americans comprise one of the most rapidly growing populations in the U.S. and within this population the process of acculturation has been suggested to be associated with some mental health problems. This study sought to ascertain quantitative information indexing acculturation stress and its association with mental health disorders in a select community sample of Mexican Americans. Methods Demographic information, DSM-III-R diagnoses, and information on cultural identity and acculturation stress were obtained from 240 Mexican American young adults that were recruited by fliers and were residing in selected areas of San Diego. Results No associations were found between measures of cultural identification and lifetime diagnoses of drug or alcohol dependence, major depressive disorder, anxiety disorders or antisocial personality disorder/conduct disorder in this sample of Mexican American young adults. However, lifetime diagnoses of alcohol dependence, substance dependence, and anxiety disorders were associated with elevations in acculturation stress. Conclusion Quantitative measures of acculturation stress, but not cultural identity per se, were found to be significantly associated with substance dependence and anxiety disorders in this select population of Mexican American young adults. These data may be helpful in designing prevention and intervention programs for this high risk population. PMID:20161543

  3. Assessing power of large river fish monitoring programs to detect population changes: the Missouri River sturgeon example

    USGS Publications Warehouse

    Wildhaber, M.L.; Holan, S.H.; Bryan, J.L.; Gladish, D.W.; Ellersieck, M.

    2011-01-01

    In 2003, the US Army Corps of Engineers initiated the Pallid Sturgeon Population Assessment Program (PSPAP) to monitor pallid sturgeon and the fish community of the Missouri River. The power analysis of PSPAP presented here was conducted to guide sampling design and effort decisions. The PSPAP sampling design has a nested structure with multiple gear subsamples within a river bend. Power analyses were based on a normal linear mixed model, using a mixed cell means approach, with variance estimates from the original data. It was found that, at current effort levels, at least 20 years for pallid and 10 years for shovelnose sturgeon is needed to detect a 5% annual decline. Modified bootstrap simulations suggest power estimates from the original data are conservative due to excessive zero fish counts. In general, the approach presented is applicable to a wide array of animal monitoring programs.

  4. Novel mobbing strategies of a fish population against a sessile annelid predator.

    PubMed

    Lachat, Jose; Haag-Wackernagel, Daniel

    2016-09-12

    When searching for food, foraging fishes expose themselves to hidden predators. The strategies that maximize the survival of foraging fishes are not well understood. Here, we describe a novel type of mobbing behaviour displayed by foraging Scolopsis affinis. The fish direct sharp water jets towards the hidden sessile annelid predator Eunice aphroditois (Bobbit worm). We recognized two different behavioural roles for mobbers (i.e., initiator and subsequent participants). The first individual to exhibit behaviour indicating the discovery of the Bobbit directed, absolutely and per time unit, more water jets than the subsequent individuals that joined the mobbing. We found evidence that the mobbing impacted the behaviour of the Bobbit, e.g., by inducing retraction. S. affinis individuals either mob alone or form mobbing groups. We speculate that this behaviour may provide social benefits for its conspecifics by securing foraging territories for S. affinis. Our results reveal a sophisticated and complex behavioural strategy to protect against a hidden predator.

  5. Novel mobbing strategies of a fish population against a sessile annelid predator

    PubMed Central

    Lachat, Jose; Haag-Wackernagel, Daniel

    2016-01-01

    When searching for food, foraging fishes expose themselves to hidden predators. The strategies that maximize the survival of foraging fishes are not well understood. Here, we describe a novel type of mobbing behaviour displayed by foraging Scolopsis affinis. The fish direct sharp water jets towards the hidden sessile annelid predator Eunice aphroditois (Bobbit worm). We recognized two different behavioural roles for mobbers (i.e., initiator and subsequent participants). The first individual to exhibit behaviour indicating the discovery of the Bobbit directed, absolutely and per time unit, more water jets than the subsequent individuals that joined the mobbing. We found evidence that the mobbing impacted the behaviour of the Bobbit, e.g., by inducing retraction. S. affinis individuals either mob alone or form mobbing groups. We speculate that this behaviour may provide social benefits for its conspecifics by securing foraging territories for S. affinis. Our results reveal a sophisticated and complex behavioural strategy to protect against a hidden predator. PMID:27615670

  6. Relationship between effective population size, inbreeding and adult fitness-related traits in a steelhead (Oncorhynchus mykiss) population released in the wild.

    PubMed

    Naish, K A; Seamons, T R; Dauer, M B; Hauser, L; Quinn, T P

    2013-03-01

    Inbreeding is of concern in supportive breeding programmes in Pacific salmonids, Oncorhynchus spp, where the number of breeding adults is limited by rearing space or poor survival to adulthood, and large numbers are released to supplement wild stocks and fisheries. We reconstructed the pedigree of 6602 migratory hatchery steelhead (Oncorhynchus mykiss) over four generations, to determine the incidence and fitness consequences of inbreeding in a northwest USA programme. The hatchery maintained an effective population size, Ñ(e) = 107.9 from F(0) to F(2), despite an increasing census size (N), which resulted in a decreasing N(e)/N ratio (0.35 in F(0) to 0.08 in F(2)). The reduced ratio was attributed to a small broodstock size, nonrandom transfers and high variance in reproductive success (particularly in males). We observed accumulation of inbreeding from the founder generation (in F(4), percentage individuals with inbreeding coefficients Δf > 0 = 15.7%). Generalized linear mixed models showed that body length and weight decreased significantly with increasing Δf, and inbred fish returned later to spawn in a model that included father identity. However, there was no significant correlation between Δf and age at return, female fecundity or gonad weight. Similarly, there was no relationship between Δf and reproductive success of F(2) and F(3) individuals, which might be explained by the fact that reproductive success is partially controlled by hatchery mating protocols. This study is one of the first to show that small changes in inbreeding coefficient can affect some fitness-related traits in a monitored population propagated and released to the wild.

  7. Population and osmoregulatory responses of a euryhaline fish to extreme salinity fluctuations in coastal lagoons of the Coorong, Australia

    NASA Astrophysics Data System (ADS)

    Wedderburn, Scotte D.; Bailey, Colin P.; Delean, Steven; Paton, David C.

    2016-01-01

    River flows and salinity are key factors structuring fish assemblages in estuaries. The osmoregulatory ability of a fish determines its capacity to tolerate rising salt levels when dispersal is unfeasible. Estuarine fishes can tolerate minor fluctuations in salinity, but a relatively small number of species in a few families can inhabit extreme hypersaline waters. The Murray-Darling Basin drains an extensive area of south-eastern Australia and river flows end at the mouth of the River Murray. The system is characterized by erratic rainfall and highly variable flows which have been reduced by intensive river regulation and water extraction. The Coorong is a coastal lagoon system extending some 110 km south-eastwards from the mouth. It is an inverted estuary with a salinity gradient that typically ranges from estuarine to triple that of sea water. Hypersalinity in the southern region suits a select suite of biota, including the smallmouth hardyhead Atherinosoma microstoma - a small-bodied, euryhaline fish with an annual life cycle. The population response of A. microstoma in the Coorong was examined during a period of considerable hydrological variation and extreme salinity fluctuations (2001-2014), and the findings were related to its osmoregulatory ability. Most notably, the species was extirpated from over 50% of its range during four continuous years without river flows when salinities exceeded 120 (2007-2010). These salinities exceeded the osmoregulatory ability of A. microstoma. Substantial river flows that reached the Coorong in late 2010 and continued into 2011 led salinities to fall below 100 throughout the Coorong by January 2012. Subsequently, A. microstoma recovered to its former range by January 2012. The findings show that the consequences of prolonged periods of insufficient river flows to temperate inverted estuaries will include substantial declines in the range of highly euryhaline fishes, which also may have wider ecological consequences.

  8. Genetic effective size is three orders of magnitude smaller than adult census size in an abundant, Estuarine-dependent marine fish (Sciaenops ocellatus).

    PubMed

    Turner, Thomas F; Wares, John P; Gold, John R

    2002-11-01

    Using eight microsatellite loci and a variety of analytical methods, we estimated genetic effective size (N(e)) of an abundant and long-lived marine fish species, the red drum (Sciaenops ocellatus), in the northern Gulf of Mexico (Gulf). The ratio N(e)/N, where short-term variance N(e) was estimated via the temporal method from shifts in allele-frequency data over four cohorts and where N reflected a current estimate of adult census size in the northern Gulf, was approximately 0.001. In an idealized population, this ratio should approximate unity. The extraordinarily low value of N(e)/N appears to arise from high variance in individual reproductive success and perhaps more importantly from variance in productivity of critical spawning and nursery habitats located in spatially discrete bays and estuaries throughout the northern Gulf. An estimate of N(e) based on a coalescent approach, which measures long-term, inbreeding effective size, was four orders of magnitude lower than the estimate of current census size, suggesting that factors presently driving N(e)/N to low values among red drum in the northern Gulf may have operated similarly in the past. Models that predict N(e)/N exclusively from demographic and life-history features will seriously overestimate N(e) if variance in reproductive success and variance in productivity among spatially discrete demes is underestimated. Our results indicate that these variances, especially variance in productivity among demes, must be large for red drum. Moreover, our study indicates that vertebrate populations with enormous adult census numbers may still be at risk relative to decline and extinction from genetic factors.

  9. Genetic effective size is three orders of magnitude smaller than adult census size in an abundant, Estuarine-dependent marine fish (Sciaenops ocellatus).

    PubMed Central

    Turner, Thomas F; Wares, John P; Gold, John R

    2002-01-01

    Using eight microsatellite loci and a variety of analytical methods, we estimated genetic effective size (N(e)) of an abundant and long-lived marine fish species, the red drum (Sciaenops ocellatus), in the northern Gulf of Mexico (Gulf). The ratio N(e)/N, where short-term variance N(e) was estimated via the temporal method from shifts in allele-frequency data over four cohorts and where N reflected a current estimate of adult census size in the northern Gulf, was approximately 0.001. In an idealized population, this ratio should approximate unity. The extraordinarily low value of N(e)/N appears to arise from high variance in individual reproductive success and perhaps more importantly from variance in productivity of critical spawning and nursery habitats located in spatially discrete bays and estuaries throughout the northern Gulf. An estimate of N(e) based on a coalescent approach, which measures long-term, inbreeding effective size, was four orders of magnitude lower than the estimate of current census size, suggesting that factors presently driving N(e)/N to low values among red drum in the northern Gulf may have operated similarly in the past. Models that predict N(e)/N exclusively from demographic and life-history features will seriously overestimate N(e) if variance in reproductive success and variance in productivity among spatially discrete demes is underestimated. Our results indicate that these variances, especially variance in productivity among demes, must be large for red drum. Moreover, our study indicates that vertebrate populations with enormous adult census numbers may still be at risk relative to decline and extinction from genetic factors. PMID:12454077

  10. Atlantic wolf-fish Anarhichas lupus population diversity: growth and maturation.

    PubMed

    Gunnarsson, Á

    2014-02-01

    Biological data from 1125 female Atlantic wolf-fish Anarhichas lupus were collected during 2002-2006 at their main spawning and fishing grounds in Iceland. The results demonstrated substantial annual variation in growth and maturity of female A. lupus. The fast growing females mature earlier than the slow growing ones. In addition, females mature at a larger size and greater age in warmer temperatures than colder ones. There was a strong negative relationship between temperature and growth, which may indicate that the sea temperature west of Iceland has risen above the optimum for growth of female A. lupus and thereby reduced the reproductive potential of the species.

  11. On the maintenance of genetic variation and adaptation to environmental change: considerations from population genomics in fishes.

    PubMed

    Bernatchez, L

    2016-12-01

    The first goal of this paper was to overview modern approaches to local adaptation, with a focus on the use of population genomics data to detect signals of natural selection in fishes. Several mechanisms are discussed that may enhance the maintenance of genetic variation and evolutionary potential, which have been overlooked and should be considered in future theoretical development and predictive models: the prevalence of soft sweeps, polygenic basis of adaptation, balancing selection and transient polymorphisms, parallel evolution, as well as epigenetic variation. Research on fish population genomics has provided ample evidence for local adaptation at the genome level. Pervasive adaptive evolution, however, seems to almost never involve the fixation of beneficial alleles. Instead, adaptation apparently proceeds most commonly by soft sweeps entailing shifts in frequencies of alleles being shared between differentially adapted populations. One obvious factor contributing to the maintenance of standing genetic variation in the face of selective pressures is that adaptive phenotypic traits are most often highly polygenic, and consequently the response to selection should derive mostly from allelic co-variances among causative loci rather than pronounced allele frequency changes. Balancing selection in its various forms may also play an important role in maintaining adaptive genetic variation and the evolutionary potential of species to cope with environmental change. A large body of literature on fishes also shows that repeated evolution of adaptive phenotypes is a ubiquitous evolutionary phenomenon that seems to occur most often via different genetic solutions, further adding to the potential options of species to cope with a changing environment. Moreover, a paradox is emerging from recent fish studies whereby populations of highly reduced effective population sizes and impoverished genetic diversity can apparently retain their adaptive potential in some

  12. Population synchrony of a native fish across three Laurentian Great Lakes: Evaluating the effects of dispersal and climate

    USGS Publications Warehouse

    Bunnell, D.B.; Adams, J.V.; Gorman, O.T.; Madenjian, C.P.; Riley, S.C.; Roseman, E.F.; Schaeffer, J.S.

    2010-01-01

    Climate and dispersal are the two most commonly cited mechanisms to explain spatial synchrony among time series of animal populations, and climate is typically most important for fishes. Using data from 1978-2006, we quantified the spatial synchrony in recruitment and population catch-per-unit-effort (CPUE) for bloater (Coregonus hoyi) populations across lakes Superior, Michigan, and Huron. In this natural field experiment, climate was highly synchronous across lakes but the likelihood of dispersal between lakes differed. When data from all lakes were pooled, modified correlograms revealed spatial synchrony to occur up to 800 km for long-term (data not detrended) trends and up to 600 km for short-term (data detrended by the annual rate of change) trends. This large spatial synchrony more than doubles the scale previously observed in freshwater fish populations, and exceeds the scale found in most marine or estuarine populations. When analyzing the data separately for within- and between-lake pairs, spatial synchrony was always observed within lakes, up to 400 or 600 km. Conversely, between-lake synchrony did not occur among short-term trends, and for long-term trends, the scale of synchrony was highly variable. For recruit CPUE, synchrony occurred up to 600 km between both lakes Michigan and Huron (where dispersal was most likely) and lakes Michigan and Superior (where dispersal was least likely), but failed to occur between lakes Huron and Superior (where dispersal likelihood was intermediate). When considering the scale of putative bloater dispersal and genetic information from previous studies, we concluded that dispersal was likely underlying within-lake synchrony but climate was more likely underlying between-lake synchrony. The broad scale of synchrony in Great Lakes bloater populations increases their probability of extirpation, a timely message for fishery managers given current low levels of bloater abundance. ?? Springer-Verlag 2009.

  13. How Nemo finds home: the neuroecology of dispersal and of population connectivity in larvae of marine fishes.

    PubMed

    Leis, Jeffrey M; Siebeck, Ulrike; Dixson, Danielle L

    2011-11-01

    Nearly all demersal teleost marine fishes have pelagic larval stages lasting from several days to several weeks, during which time they are subject to dispersal. Fish larvae have considerable swimming abilities, and swim in an oriented manner in the sea. Thus, they can influence their dispersal and thereby, the connectivity of their populations. However, the sensory cues marine fish larvae use for orientation in the pelagic environment remain unclear. We review current understanding of these cues and how sensory abilities of larvae develop and are used to achieve orientation with particular emphasis on coral-reef fishes. The use of sound is best understood; it travels well underwater with little attenuation, and is current-independent but location-dependent, so species that primarily utilize sound for orientation will have location-dependent orientation. Larvae of many species and families can hear over a range of ~100-1000 Hz, and can distinguish among sounds. They can localize sources of sounds, but the means by which they do so is unclear. Larvae can hear during much of their pelagic larval phase, and ontogenetically, hearing sensitivity, and frequency range improve dramatically. Species differ in sensitivity to sound and in the rate of improvement in hearing during ontogeny. Due to large differences among-species within families, no significant differences in hearing sensitivity among families have been identified. Thus, distances over which larvae can detect a given sound vary among species and greatly increase ontogenetically. Olfactory cues are current-dependent and location-dependent, so species that primarily utilize olfactory cues will have location-dependent orientation, but must be able to swim upstream to locate sources of odor. Larvae can detect odors (e.g., predators, conspecifics), during most of their pelagic phase, and at least on small scales, can localize sources of odors in shallow water, although whether they can do this in pelagic

  14. Peripatric differentiation among adjacent marine lake and lagoon populations of a coastal fish, Sphaeramia orbicularis (Apogonidae, Perciformes, Teleostei).

    PubMed

    Gotoh, Ryo O; Sekimoto, Hidekatsu; Chiba, Satoru N; Hanzawa, Naoto

    2009-08-01

    The effect of geographical isolation on speciation, particularly within short geographical ranges, is poorly understood among marine organisms. Focusing on marine lakes of the Palau Islands, we investigated the effect of geographical isolation on Sphaeramia orbicularis, a coastal fish inhabiting marine lakes and lagoons. We collected a total of 157 individuals from three meromictic marine lakes and three lagoon sites, and analyzed the genetic diversity and differentiation of the populations based on complete sequences of the mitochondrial control region (824 bp). The analyses show that the genetic diversity of marine lake populations is much lower than that of lagoon populations. Moreover, a mismatch distribution analysis suggests that marine lake populations have experienced a decrease followed by a rapid expansion of their population size. These results reveal that marine lake populations have experienced severe founder and/or bottleneck events during the last thousand to tens of thousand years. Pairwise Phi(ST )values ranged from 0.531 to 0.848 between marine lake and lagoon populations and from 0.429 to 0.870 among marine lake populations, indicating a high degree of genetic differentiation. We speculate that such peripatric differentiation between marine lake and lagoon populations was caused by a small number of individuals colonizing the lakes from the lagoon (founder event) followed by repetitive bottleneck events, such as those generated by the El Niño-Southern Oscillation (ENSO). So far, such high genetic divergences in extremely short geographical ranges (approximately 150-250 m) have scarcely been reported for marine organisms. We suggest that the marine lake is one of the good model of geographical isolation in marine organisms and each marine lake population is in the early stages of speciation.

  15. Intentional genetic introgression influences survival of adults and subadults in a small, inbred felid population.

    PubMed

    Benson, John F; Hostetler, Jeffrey A; Onorato, David P; Johnson, Warren E; Roelke, Melody E; O'Brien, Stephen J; Jansen, Deborah; Oli, Madan K

    2011-09-01

    1. Inbreeding and low genetic diversity can cause reductions in individual fitness and increase extinction risk in animal populations. Intentional introgression, achieved by releasing genetically diverse individuals into inbred populations, has been used as a conservation tool to improve demographic performance in endangered populations. 2. By the 1980s, Florida panthers (Puma concolor coryi) had been reduced to a small, inbred population that appeared to be on the brink of extinction. In 1995, female pumas from Texas (P. c. stanleyana) were released in occupied panther range as part of an intentional introgression programme to restore genetic variability and improve demographic performance of panthers. 3. We used 25 years (1981-2006) of continuous radiotelemetry and genetic data to estimate and model subadult and adult panther survival and cause-specific mortality to provide rigorous sex and age class-specific survival estimates and evaluate the effect of the introgression programme on these parameters. 4. Genetic ancestry influenced annual survival of subadults and adults after introgression, as F(1) generation admixed panthers ( = 0·98) survived better than pre-introgression type panthers ( = 0·77) and other admixed individuals ( = 0·82). Furthermore, heterozygosity was higher for admixed panthers relative to pre-introgression type panthers and positively influenced survival. 5. Our results are consistent with hybrid vigour; however, extrinsic factors such as low density of males in some areas of panther range may also have contributed to higher survival of F(1) panthers. Regardless, improved survival of F(1) subadults and adults likely contributed to the numerical increase in panthers following introgression, and our results indicate that intentional admixture, achieved here by releasing individuals from another population, appears to have been successful in improving demographic performance in this highly endangered population.

  16. Differences in absorption, distribution, metabolism and excretion of xenobiotics between the paediatric and adult populations.

    PubMed

    Strolin Benedetti, M; Whomsley, R; Baltes, E L

    2005-10-01

    In children, the therapeutic benefits and potential risks associated with drug treatment may be different from those in adults and will depend on the exposure, receptor sensitivity and relationship between effect and exposure. In this paper, key factors undergoing maturational changes accounting for differences in drug metabolism and disposition in the paediatric population compared with adults are reviewed. Gastric and duodenal pH, gastric emptying time, intestinal transit time, secretion and activity of bile and pancreatic fluid, bacterial colonisation and transporters, such as P-glycoprotein (P-gp), are important factors for drug absorption, whereas key factors explaining differences in drug distribution between the paediatric population and adults are organ size, membrane permeability, plasma protein concentration and characteristics, endogenous substances in plasma, total body and extracellular water, fat content, regional blood flow and transporters such as P-gp, which is present not only in the gut, but also in liver, kidney, brain and other tissues. As far as drug metabolism is concerned, important differences have been found in the paediatric population compared with adults both for phase I enzymes (oxidative [e.g., cytochrome P450 (CYP)1A2, and CYP3A7 versus -3A4], reductive and hydrolytic enzymes) and phase II enzymes (e.g., N-methyltransferases and glucuronosyltransferases). Generally, the major enzyme differences observed in comparison with the adult age are in newborn infants, although for some enzymes (e.g., glucuronosyltransferases and other phase II enzymes) important differences still exist between infants and toddlers and adults. Finally, key factors undergoing maturational changes accounting for differences in renal excretion in the paediatric population compared with adults are glomerular filtration and tubular secretion. The ranking of the key factors varies according to the chemical structure and physicochemical properties of the drug

  17. HISTOPATHOLOGIC BIOMARKERS IN FERAL FRESHWATER FISH POPULATIONS EXPOSED TO DIFFERENT TYPES OF CONTAMINANT STRESS. (R825433)

    EPA Science Inventory

    Histopathologic alterations of gill, liver, and spleen were studied in feral fish from three freshwater ecosystems that experience different types of contaminant stress. East Fork Poplar Creek (EFPC), a third-order stream in East Tennessee, receives point source discharges of ...

  18. RETINOID METABOLISM IN FISH EMBRYOS FROM SENSITIVE AND RESISTANT POPULATIONS EXPOSED TO DIOXIN-LIKE COMPOUNDS

    EPA Science Inventory

    Early developmental stages of fish are extremely sensitive to a class of toxic and persistent environmental contaminants known as dioxin-like compounds (DLCs). Most of the toxicological actions of DLCs are mediated via the Aryl hydrocarbon Receptor (AhR) that regulates transcript...

  19. Application of Biochemical and Physiological Indicators for Assessing Recovery of Fish Populations in a Disturbed Stream

    SciTech Connect

    Adams, S. M.; Ham, Kenneth D.

    2011-06-01

    Recovery dynamics in a previously disturbed streamwere investigated to determine the influence of a series of remedial actions on stream recovery and to evaluate the potential application of bioindicators as an environmental management tool. A suite of bioindicators, representing five different functional response groups, were measured annually for a sentinel fish species over a 15 year period during which a variety of remedial and pollution abatement actions were implemented. Trends in biochemical, physiological, condition, growth, bioenergetic, and nutritional responses demonstrated that the health status of a sentinel fish species in the disturbed stream approached that of fish in the reference stream by the end of the study. Two major remedial actions, dechlorination and water flow management, had large effects on stream recovery resulting in an improvement in the bioenergetic, disease, nutritional, and organ condition status of the sentinel fish species. A subset of bioindicators responded rather dramatically to temporal trends affecting all sites, but some indicators showed little response to disturbance or to restoration activities. In assessing recovery of aquatic systems, application of appropriate integrative structural indices along with a variety of sensitive functional bioindicators should be used to understand the mechanistic basis of stress and recovery and to reduce the risk of false positives. Understanding the mechanistic processes involved between stressors, stress responses of biota, and the recovery dynamics of aquatic systems reduces the uncertainty involved in environmental management and regulatory decisions resulting in an increased ability to predict the consequences of restoration and remedial actions for aquatic systems.

  20. Application of Biochemical and Physiological Indicators for Assessing Recovery of Fish Populations in a Disturbed Stream

    SciTech Connect

    Adams, Marshall; Ham, Kenneth

    2011-01-01

    Recovery dynamics in a previously disturbed streamwere investigated to determine the influence of a series of remedial actions on stream recovery and to evaluate the potential application of bioindicators as an environmental management tool. A suite of bioindicators, representing five different functional response groups, were measured annually for a sentinel fish species over a 15 year period during which a variety of remedial and pollution abatement actions were implemented. Trends in biochemical, physiological, condition, growth, bioenergetic, and nutritional responses demonstrated that the health status of a sentinel fish species in the disturbed stream approached that of fish in the reference stream by the end of the study. Two major remedial actions, dechlorination and water flow management, had large effects on stream recovery resulting in an improvement in the bioenergetic, disease, nutritional, and organ condition status of the sentinel fish species. A subset of bioindicators responded rather dramatically to temporal trends affecting all sites, but some indicators showed little response to disturbance or to restoration activities. In assessing recovery of aquatic systems, application of appropriate integrative structural indices along with a variety of sensitive functional bioindicators should be used to understand the mechanistic basis of stress and recovery and to reduce the risk of false positives. Understanding the mechanistic processes involved between stressors, stress responses of biota, and the recovery dynamics of aquatic systems reduces the uncertainty involved in environmental management and regulatory decisions resulting in an increased ability to predict the consequences of restoration and remedial actions for aquatic systems.

  1. Restoring piscivorous fish populations in the Laurentian Great Lakes causes seabird dietary change

    USGS Publications Warehouse

    Hebert, C.E.; Weseloh, D.V.C.; Idrissi, A.; Arts, M.T.; O'Gorman, R.; Gorman, O.T.; Locke, B.; Madenjian, C.P.; Roseman, E.F.

    2008-01-01

    Ecosystem change often affects the structure of aquatic communities thereby regulating how much and by what pathways energy and critical nutrients flow through food webs. The availability of energy and essential nutrients to top predators such as seabirds that rely on resources near the water's surface will be affected by changes in pelagic prey abundance. Here, we present results from analysis of a 25-year data set documenting dietary change in a predatory seabird from the Laurentian Great Lakes. We reveal significant declines in trophic position and alterations in energy and nutrient flow over time. Temporal changes in seabird diet tracked decreases in pelagic prey fish abundance. As pelagic prey abundance declined, birds consumed less aquatic prey and more terrestrial food. This pattern was consistent across all five large lake ecosystems. Declines in prey fish abundance may have primarily been the result of predation by stocked piscivorous fishes, but other lake-specific factors were likely also important. Natural resource management activities can have unintended consequences for nontarget ecosystem components. Reductions in pelagic prey abundance have reduced the capacity of the Great Lakes to support the energetic requirements of surface-feeding seabirds. In an environment characterized by increasingly limited pelagic fish resources, they are being offered a Hobsonian choice: switch to less nutritious terrestrial prey or go hungry. ?? 2008 by the Ecological Society of America.

  2. Effects of hydrologic infrastructure on flow regimes of California's Central Valley rivers: Implications for fish populations

    USGS Publications Warehouse

    Brown, Larry R.; Bauer, Marissa L.

    2010-01-01

    Alteration of natural flow regimes is generally acknowledged to have negative effects on native biota; however, methods for defining ecologically appropriate flow regimes in managed river systems are only beginning to be developed. Understanding how past and present water management has affected rivers is an important part of developing such tools. In this paper, we evaluate how existing hydrologic infrastructure and management affect streamflow characteristics of rivers in the Central Valley, California and discuss those characteristics in the context of habitat requirements of native and alien fishes. We evaluated the effects of water management by comparing observed discharges with estimated discharges assuming no water management ("full natural runoff"). Rivers in the Sacramento River drainage were characterized by reduced winter–spring discharges and augmented discharges in other months. Rivers in the San Joaquin River drainage were characterized by reduced discharges in all months but particularly in winter and spring. Two largely unaltered streams had hydrographs similar to those based on full natural runoff of the regulated rivers. The reduced discharges in the San Joaquin River drainage streams are favourable for spawning of many alien species, which is consistent with observed patterns of fish distribution and abundance in the Central Valley. However, other factors, such as water temperature, are also important to the relative success of native and alien resident fishes. As water management changes in response to climate change and societal demands, interdisciplinary programs of research and monitoring will be essential for anticipating effects on fishes and to avoid unanticipated ecological outcomes.

  3. A juvenile-adult population model: climate change, cannibalism, reproductive synchrony, and strong Allee effects.

    PubMed

    Veprauskas, Amy; Cushing, J M

    2017-03-01

    We study a discrete time, structured population dynamic model that is motivated by recent field observations concerning certain life history strategies of colonial-nesting gulls, specifically the glaucous-winged gull (Larus glaucescens). The model focuses on mechanisms hypothesized to play key roles in a population's response to degraded environment resources, namely, increased cannibalism and adjustments in reproductive timing. We explore the dynamic consequences of these mechanics using a juvenile-adult structure model. Mathematically, the model is unusual in that it involves a high co-dimension bifurcation at [Formula: see text] which, in turn, leads to a dynamic dichotomy between equilibrium states and synchronized oscillatory states. We give diagnostic criteria that determine which dynamic is stable. We also explore strong Allee effects caused by positive feedback mechanisms in the model and the possible consequence that a cannibalistic population can survive when a non-cannibalistic population cannot.

  4. Links between Childhood and Adult Social Circumstances and Obesity and Hypertension in the Mexican Population

    PubMed Central

    Beltrán-Sánchez, Hiram; Crimmins, Eileen M.; Teruel, Graciela M.; Thomas, Duncan

    2011-01-01

    Objectives This study examines links between early life circumstances and adult socioeconomic status and obesity and hypertension in the adult Mexican population. Methods We use data from the Mexican Family Life Survey (MxFLS) collected in 2002 for people aged 20 or older (N=14, 280). Results We found that men with low education and women with more education have significantly lower obesity. Women with higher education also have significantly less hypertension. Obesity triples the likelihood of hypertension among both men and women. Better childhood experiences are associated with less hypertension among women, but more hypertension among men in rural areas. Discussion Recent changes in income, nutrition, and infection in Mexico may be responsible for the observed high prevalence of overweight and obesity and the extremely high odds of hypertension among obese young adults. PMID:21948773

  5. Is there enough zooplankton to feed forage fish populations off Peru? An acoustic (positive) answer

    NASA Astrophysics Data System (ADS)

    Ballón, Michael; Bertrand, Arnaud; Lebourges-Dhaussy, Anne; Gutiérrez, Mariano; Ayón, Patricia; Grados, Daniel; Gerlotto, François

    2011-12-01

    The Northern Humboldt Current system (NHCS) produces more fish per unit area than any other region in the world. Although the system produces enough macrozooplankton to sustain its high production of forage fish, the paucity of information on macrozooplankton hampers research into the system. In this study, we estimated the biomass of the epipelagic crustacean macrozooplankton from the NHCS during both austral summer and spring 2005. To do this, we developed a bi-frequency acoustic method and extracted high-resolution information on the biomass and the patterns of distribution of crustacean macrozooplankton, fish and other marine compartments. We found that, although macrozooplankton comprises a number of distinct organisms, the euphausiids were the zooplankton group that better fitted the patterns from independent net sampling zooplankton data. Also, the similarities between the nocturnal patterns of size and biomass macrozooplankton distribution from this study and the known patterns of euphausiids, in particular Euphausia mucronata, suggest that euphausiids were the main constituent of the estimated nocturnal acoustic macrozooplankton biomass even if other organisms such as large copepods may have contributed considerably to the macrozooplankton biomass. The total macrozooplankton biomass was estimated to about 105 g m -2, i.e., two to five times more than previous estimates. This direct biomass estimation of macrozooplankton is in agreement with the new findings in trophic ecology indicating that forage fish consume mainly macrozooplankton. This high biomass also supports the current hypotheses explaining the NHCS high fish production. Using the method, we are able to revisit present-day and historical acoustic databases and extract high-resolution data on macrozooplankton, a key ecological compartment of the ecosystem. Since zooplankton is the link between the physically driven primary producers and the biologically driven tertiary consumers, this information

  6. A fully-stochasticized, age-structured population model for population viability analysis of fish: Lower Missouri River endangered pallid sturgeon example

    USGS Publications Warehouse

    Wildhaber, Mark L.; Albers, Janice; Green, Nicholas; Moran, Edward H.

    2015-01-01

    We develop a fully-stochasticized, age-structured population model suitable for population viability analysis (PVA) of fish and demonstrate its use with the endangered pallid sturgeon (Scaphirhynchus albus) of the Lower Missouri River as an example. The model incorporates three levels of variance: parameter variance (uncertainty about the value of a parameter itself) applied at the iteration level, temporal variance (uncertainty caused by random environmental fluctuations over time) applied at the time-step level, and implicit individual variance (uncertainty caused by differences between individuals) applied within the time-step level. We found that population dynamics were most sensitive to survival rates, particularly age-2+ survival, and to fecundity-at-length. The inclusion of variance (unpartitioned or partitioned), stocking, or both generally decreased the influence of individual parameters on population growth rate. The partitioning of variance into parameter and temporal components had a strong influence on the importance of individual parameters, uncertainty of model predictions, and quasiextinction risk (i.e., pallid sturgeon population size falling below 50 age-1+ individuals). Our findings show that appropriately applying variance in PVA is important when evaluating the relative importance of parameters, and reinforce the need for better and more precise estimates of crucial life-history parameters for pallid sturgeon.

  7. Seroepidemiology of dengue virus infection in the adult population in tropical Singapore.

    PubMed

    Ang, L W; Cutter, J; James, L; Goh, K T

    2015-06-01

    To assess the impact of past dengue epidemics in Singapore, we undertook a national seroepidemiological study to determine the prevalence of past dengue virus (DENV) infection in the adult population in 2010 and make comparisons with the seroprevalence in 2004. The study involved residual sera from 3293 adults aged 18-79 years who participated in a national health survey in 2010. The overall prevalence of anti-DENV IgG antibodies was 56·8% (95% confidence interval 55·1-58·5) in 2010. The seroprevalence increased significantly with age. Males had significantly higher seroprevalence than females (61·5% vs. 53·2%). Among the three major ethnic groups, Malays had the lowest seroprevalence (50·2%) compared to Chinese (57·0%) and Indians (62·0%). The age-standardized seroprevalence in adults was significantly lower in 2010 (54·4%) compared to 2004 (63·1%). Older age, male gender, Indian ethnicity, permanent residency and being home-bound were independent risk factors significantly associated with seropositivity. About 43% of the Singapore adult resident population remain susceptible to DENV infection as a result of the successful implementation of a comprehensive nationwide Aedes surveillance and control programme since the 1970s. Vector suppression and concerted efforts of all stakeholders in the community remain the key strategy in the prevention and control of dengue.

  8. Amplifying diffusion of health information in low-literate populations through adult education health literacy classes.

    PubMed

    Freedman, Ariela M; Miner, Kathleen R; Echt, Katharina V; Parker, Ruth; Cooper, Hannah L F

    2011-01-01

    Over the next decade, as literacy rates are predicted to decline, the health care sector faces increasing challenges to effective communication with low-literate groups. Considering the rising costs of health care and the forthcoming changes in the American health care system, it is imperative to find nontraditional avenues through which to impart health knowledge and functional skills. This article draws on classroom observations and qualitative interviews with 21 students and 3 teachers in an adult education health literacy class to explore the efficacy of using adult education courses to teach functional health literacy skills to low-literate populations. Data were analyzed using a combination of thematic and content analyses. Results describe the motivation of students to share information within the classroom and with friends and family outside the classroom. This article also provides several recommendations to help ensure accuracy of diffused information both within and outside of the classroom. Ultimately, this study suggests that the adult education system is in a prime position to impart functional health literacy skills to low-literate populations in the classroom. Significantly, this study demonstrates that adult education students themselves may be a powerful vehicle for health communication beyond the walls of the classroom.

  9. DEVELOPMENT OF A DNA ARCHIVE FOR GENETIC MONITORING OF FISH POPULATIONS

    EPA Science Inventory

    Analysis of intraspecific genetic diversity provides a potentially powerful tool to estimate the impacts of environmental stressors on populations. Genetic responses of populations to novel stressors include dramatic shifts in genotype frequencies at loci under selection (i.e. ad...

  10. INDIVIDUAL EFFECTS OF THREE STEROIDAL ESTROGENS ON A FISH EXTRAPOLATED TO THE POPULATION LEVEL

    EPA Science Inventory

    Endocrine disrupting chemicals (EDCs) in the environment may disturb the population dynamics of wildlife by affecting reproductive output and early life survival of organisms. This study used a population model and data obtained from laboratory experimentation and the literature ...

  11. FINE-SCALE GENETIC DIFFERENTIATION BETWEEN CONTAMINANT-TOLERANT AND CONTAMINANT SENSITIVE FISH POPULATIONS

    EPA Science Inventory

    Studies have suggested that environmental contaminants can act as selective forces on exposed populations of wildlife species. Chronically exposed populations have shown reduced genetic diversity and/or demonstrated other genetic changes. We evaluated the genetic structure of pop...

  12. Increased reports of measles in a low endemic region during a rubella outbreak in adult populations.

    PubMed

    Kurata, Takako; Kanbayashi, Daiki; Nishimura, Hiroshi; Komano, Jun; Kase, Tetsuo; Takahashi, Kazuo

    2015-06-01

    In 2013, a rubella outbreak was observed in Japan, Romania, and Poland. The outbreak in Japan was accompanied by an increase of measles reports, especially from a region where measles is highly controlled. This was attributed to the adult populations affected by this rubella outbreak, similarity of clinical signs between rubella and measles, sufficiently small impact of measles outbreaks from neighboring nations, and elimination levels of measles endemicity. Current and future concerns for measles control are discussed.

  13. Human growth hormone (GH1) gene polymorphism map in a normal-statured adult population

    PubMed Central

    Esteban, Cristina; Audí, Laura; Carrascosa, Antonio; Fernández-Cancio, Mónica; Pérez-Arroyo, Annalisa; Ulied, Angels; Andaluz, Pilar; Arjona, Rosa; Albisu, Marian; Clemente, María; Gussinyé, Miquel; Yeste, Diego

    2007-01-01

    Objective GH1 gene presents a complex map of single nucleotide polymorphisms (SNPs) in the entire promoter, coding and noncoding regions. The aim of the study was to establish the complete map of GH1 gene SNPs in our control normal population and to analyse its association with adult height. Design, subjects and measurements A systematic GH1 gene analysis was designed in a control population of 307 adults of both sexes with height normally distributed within normal range for the same population: −2 standard deviation scores (SDS) to +2 SDS. An analysis was performed on individual and combined genotype associations with adult height. Results Twenty-five SNPs presented a frequency over 1%: 11 in the promoter (P1 to P11), three in the 5′UTR region (P12 to P14), one in exon 1 (P15), three in intron 1 (P16 to P18), two in intron 2 (P19 and P20), two in exon 4 (P21 and P22) and three in intron 4 (P23 to P25). Twenty-nine additional changes with frequencies under 1% were found in 29 subjects. P8, P19, P20 and P25 had not been previously described. P6, P12, P17 and P25 accounted for 6·2% of the variation in adult height (P = 0·0007) in this population with genotypes A/G at P6, G/G at P6 and A/G at P12 decreasing height SDS (−0·063 ± 0·031, −0·693 ± 0·350 and −0·489 ± 0·265, Mean ± SE) and genotypes A/T at P17 and T/G at P25 increasing height SDS (+1·094 ± 0·456 and +1·184 ± 0·432). Conclusions This study established the GH1 gene sequence variation map in a normal adult height control population confirming the high density of SNPs in a relatively small gene. Our study shows that the more frequent SNPs did not significantly contribute to height determination, while only one promoter and two intronic SNPs contributed significantly to it. Studies in larger populations will have to confirm the associations and in vitro functional studies will elucidate the mechanisms involved. Systematic GH1 gene analysis in patients with growth delay and suspected

  14. The Effect of HIFA Waiver Expansions on Uninsurance Rates in Adult Populations

    PubMed Central

    Atherly, Adam; Dowd, Bryan E; Coulam, Robert F; Guy, Gery

    2012-01-01

    Research Objective To evaluate the effect of the Health Insurance Flexibility and Accountability (HIFA) demonstrations on the rate of uninsured. The policy purpose of the HIFA demonstrations is to encourage “new comprehensive state approaches” that will increase the number of insured. HIFA interventions include changes in benefit packages, eligibility rules for public programs, and state subsidization of private health insurance premiums. Some states emphasized private insurance (premium assistance), whereas others placed greater emphasis on expanded eligibility for public insurance. Data Sources/Study Setting Data were drawn from the Current Population Survey from 2000 to 2007. The target populations for the HIFA waiver demonstrations consisted of individuals who were eligible for the HIFA waiver demonstrations in demonstration states. Study Design The estimation approach was a probit model using a difference-in-differences approach. Principal Findings In states that fully implemented their HIFA waiver, HIFA increased the rate of insurance coverage by 6.4 percentage points on average in the targeted adult population, suggesting that approximately 118,848 adults gained health insurance due to HIFA. Total HIFA adult enrollment in the six states studied was 280,739. The effect size varied by state, with Maine having the largest effect and Illinois the smallest. The results were robust to different specifications of the control group. Conclusions Our findings suggest that public insurance initiatives that provide states with flexibility regarding eligibility and plan design are a viable policy approach to reducing uninsurance rates. PMID:22299673

  15. Diffusely adherent Escherichia coli strains isolated from children and adults constitute two different populations

    PubMed Central

    2013-01-01

    Background Diffusely adherent Escherichia coli (DAEC) have been considered a diarrheagenic category of E. coli for which several potential virulence factors have been described in the last few years. Despite this, epidemiological studies involving DAEC have shown inconsistent results. In this work, two different collections of DAEC possessing Afa/Dr genes, from children and adults, were studied regarding characteristics potentially associated to virulence. Results DAEC strains were recovered in similar frequencies from diarrheic and asymptomatic children, and more frequently from adults with diarrhea (P < 0.01) than from asymptomatic adults. Association with diarrhea (P < 0.05) was found for SAT-positive strains recovered from children and for curli-positive strains recovered from adults. Mixed biofilms involving DAEC and a Citrobacter freundii strain have shown an improved ability to form biofilms in relation to the monocultures. Control strains have shown a greater diversity of Afa/Dr adhesins and higher frequencies of cellulose, TTSS, biofilm formation and induction of IL-8 secretion than strains from cases of diarrhea in children. Conclusions DAEC strains possessing Afa/Dr genes isolated from children and adults represent two different bacterial populations. DAEC strains carrying genes associated to virulence can be found as part of the normal microbiota present in asymptomatic children. PMID:23374248

  16. Adult mortality in a low-density tree population using high-resolution remote sensing.

    PubMed

    Kellner, James R; Hubbell, Stephen P

    2017-04-04

    We developed a statistical framework to quantify mortality rates in canopy trees observed using time series from high-resolution remote sensing. By timing the acquisition of remote sensing data with synchronous annual flowering in the canopy tree species Handroanthus guayacan, we made 2,596 unique detections of 1,006 individual adult trees within 18,883 observation attempts on Barro Colorado Island, Panama (BCI) during an 11-year period. There were 1,057 observation attempts that resulted in missing data due to cloud cover or incomplete spatial coverage. Using the fraction of 123 individuals from an independent field sample that were detected by satellite data (109 individuals, 88.6%), we estimate that the adult population for this species on BCI was 1,135 individuals. We used a Bayesian state-space model that explicitly accounted for the probability of tree detection and missing observations to compute an annual adult mortality rate of 0.2% · yr(-1) (SE = 0.1, 95% CI = 0.06 - 0.45). An independent estimate of the adult mortality rate from 260 field-checked trees closely matched the landscape-scale estimate (0.33% · yr(-1) , SE = 0.16, 95% CI = 0.12 - 0.74). Our proof-of-concept study shows that one can remotely estimate adult mortality rates for canopy tree species precisely in the presence of variable detection and missing observations. This article is protected by copyright. All rights reserved.

  17. Assessment of the relationship among acidifying depositions, surface water acidification, and fish populations in North America. Volume 1. Final report

    SciTech Connect

    Marcus, M.D.; Parkhurst, B.R.; Payne, F.E.

    1983-06-01

    This report assesses the scientific understanding about relationships between acidic depositions and freshwater aquatic resources. Selected surface waters in eastern North America are becoming acidified and fish populations are being eliminated. The actual extent of these resources threatened by acidification is now known. Mostly circumstantial evidence has been compiled to suggest that long-range atmospheric transport of acidifying compounds is causing surface-water acidification in North America. Certainly, atmospheric emissions from point sources can impact localized areas. However, some data indicate that atmospheric inputs of acids from long-range transport may add little to the natural flux of acids within ecosystems. The degree of influence that atmosphere depositions can have in accelerating natural acidification rates is unknown for most potentially sensitive surface waters. Fish losses appear to result from (1) long-term accumulations of acids and metals reaching chronically toxic concentrations; and (2) short-term, episodic events causing acutely toxic acid and metal concentrations. Some impacts may be successfully mitigated through several methods. Additional research is needed to (1) identify causes of surface-water acidification; (2) develop innovative mitigation measures; (3) define mechanisms of fish loss; and (4) establish the extent of aquatic resources at risk.

  18. Levels of Health Literacy in a Community-Dwelling Population of Chinese Older Adults

    PubMed Central

    Li, Yu; Dong, XinQi

    2014-01-01

    Background. Lower levels of health literacy have been associated with adverse health outcomes, especially for older adults. However, limited research has been conducted to understand health literacy levels among Chinese American older adults. Methods. The PINE study is an epidemiological cohort of 3,159 community-dwelling Chinese older adults, 95% of whom do not speak or read English. Chinese older adults’ health literacy levels were examined using the Chinese version of the Rapid Estimate of Adult Literacy in Medicine, Revised (REALM-R) test. Kruskal–Wallis test and chi-square statistics were used to identify significant differences by sociodemographic and self-reported health characteristics. Pearson and Spearman correlation coefficients were used to examine correlations between personal characteristics and health literacy level. Results. The mean age among this sample of Chinese older adults was 72.8 years (SD = 8.3, range = 60–105) and the mean REALM-R test score was 6.9 [SD = 2.3, range (0–8)]. Health literacy was positively associated with education, marriage status, and number of people living with. Older age, being female, greater number of children, years in the United States, and preference for speaking Cantonese or Taishanese were negatively associated with health literacy. Health literary was not associated with self-reported health status or quality of life. Conclusions. In this Chicago Chinese population, older adults had reasonable levels of health literacy in Chinese. Future longitudinal research is needed to understand risk/protective factors associated with health literacy level in Chinese older adults. PMID:25378449

  19. Prevalence of self-medication in the adult population of Brazil: a systematic review

    PubMed Central

    Domingues, Paulo Henrique Faria; Galvão, Taís Freire; de Andrade, Keitty Regina Cordeiro; de Sá, Pedro Terra Teles; Silva, Marcus Tolentino; Pereira, Mauricio Gomes

    2015-01-01

    OBJECTIVE To evaluate the prevalence of self-medication in Brazil’s adult population. METHODS Systematic review of cross-sectional population-based studies. The following databases were used: Medline, Embase, Scopus, ISI, CINAHL, Cochrane Library, CRD, Lilacs, SciELO, the Banco de teses brasileiras (Brazilian theses database) (Capes) and files from the Portal Domínio Público (Brazilian Public Domain). In addition, the reference lists from relevant studies were examined to identify potentially eligible articles. There were no applied restrictions in terms of the publication date, language or publication status. Data related to publication, population, methods and prevalence of self-medication were extracted by three independent researchers. Methodological quality was assessed following eight criteria related to sampling, measurement and presentation of results. The prevalences were measured from participants who used at least one medication during the recall period of the studies. RESULTS The literature screening identified 2,778 records, from which 12 were included for analysis. Most studies were conducted in the Southeastern region of Brazil, after 2000 and with a 15-day recall period. Only five studies achieved high methodological quality, of which one study had a 7-day recall period, in which the prevalence of self-medication was 22.9% (95%CI 14.6;33.9). The prevalence of self-medication in three studies of high methodological quality with a 15-day recall period was 35.0% (95%CI 29.0;40.0, I2 = 83.9%) in the adult Brazilian population. CONCLUSIONS Despite differences in the methodologies of the included studies, the results of this systematic review indicate that a significant proportion of the adult Brazilian population self-medicates. It is suggested that future research projects that assess self-medication in Brazil standardize their methods. PMID:26083944

  20. The role of spatial dynamics in the stability, resilience, and productivity of an estuarine fish population.

    PubMed

    Kerr, L A; Cadrin, S X; Secor, D H

    2010-03-01

    Understanding mechanisms that support long-term persistence of populations and sustainability of productive fisheries is a priority in fisheries management. Complex spatial structure within populations is increasingly viewed as a result of a plastic behavioral response that can have consequences for the dynamics of a population. We incorporated spatial structure and environmental forcing into a population model to examine the consequences for population stability (coefficient of variation of spawning-stock biomass), resilience (time to recover from disturbance), and productivity (spawning-stock biomass). White perch (Morone americana) served as a model species that exhibits simultaneous occurrence of migratory and resident groups within a population. We evaluated the role that contingents (behavioral groups within populations that exhibit divergent life histories) play in mitigating population responses to unfavorable environmental conditions. We used age-structured models that incorporated contingent-specific vital rates to simulate population dynamics of white perch in a sub-estuary of Chesapeake Bay, USA. The dynamics of the population were most sensitive to the proportion of individuals within each contingent and to a lesser degree to the level of correlation in recruitment between contingents in their responses to the environment. Increased representation of the dispersive contingent within populations resulted in increased productivity and resilience, but decreased stability. Empirical evidence from the Patuxent River white perch population was consistent with these findings. A high negative correlation in resident and dispersive contingent recruitment dynamics resulted in increased productivity and stability, with little effect on resilience. With high positive correlation between contingent recruitments, the model showed similar responses in population productivity and resilience, but decreased stability. Because contingent structure involves differing

  1. Space-use, movement and dispersal of sub-adult cougars in a geographically isolated population

    PubMed Central

    Boyce, Mark S.; Nielsen, Scott E.

    2015-01-01

    Cougar (Puma concolor) observations have increased in Midwest North America, with breeding populations re-establishing in several regions east of their contemporary range. The Cypress Hills Uplands, located in southwest Saskatchewan and southeast Alberta, was recently re-colonized by cougars and now supports the easternmost confirmed breeding population of cougars in Canada. A number of factors contribute to this cougar range expansion, but it is dispersal that provides the mechanism for re-colonization of historic range. We used GPS-collar data to examine space-use and movement behavior of sub-adult cougars, the age class associated with dispersal, in the Cypress Hills. Conditional logistic regression and a two-stage modeling approach were used to estimate resource selection functions (RSF) of sub-adult cougars during two distinct ranging behaviors: transient movements (i.e., dispersal and exploratory forays) and localizing movements (i.e., temporary home ranges). Linear regression was used to model movement rates, measured as the distance between consecutive 3-h GPS-relocations, of sub-adult cougars relative to different habitats, times of day and between transient and localizing behavior. All individual sub-adult cougars displayed bouts of transient and localizing behavior. All male cougars dispersed from their natal ranges and travelled considerably farther distances than female cougars. One male dispersed over 750 km eastward through the agricultural belt of northern Montana and southern Saskatchewan. Males occupied temporary home ranges in more open habitats on the fringes of the insular Cypress Hills, while females appeared to be recruited into the adult population, occupying treed habitat that provided more suitable cover. During both ranging behaviors, sub-adult cougars selected for rugged terrain and proximity to hydrological features (likely supporting riparian habitats) and avoided open cover types. Differences in habitat selection between ranging

  2. Space-use, movement and dispersal of sub-adult cougars in a geographically isolated population.

    PubMed

    Morrison, Carl D; Boyce, Mark S; Nielsen, Scott E

    2015-01-01

    Cougar (Puma concolor) observations have increased in Midwest North America, with breeding populations re-establishing in several regions east of their contemporary range. The Cypress Hills Uplands, located in southwest Saskatchewan and southeast Alberta, was recently re-colonized by cougars and now supports the easternmost confirmed breeding population of cougars in Canada. A number of factors contribute to this cougar range expansion, but it is dispersal that provides the mechanism for re-colonization of historic range. We used GPS-collar data to examine space-use and movement behavior of sub-adult cougars, the age class associated with dispersal, in the Cypress Hills. Conditional logistic regression and a two-stage modeling approach were used to estimate resource selection functions (RSF) of sub-adult cougars during two distinct ranging behaviors: transient movements (i.e., dispersal and exploratory forays) and localizing movements (i.e., temporary home ranges). Linear regression was used to model movement rates, measured as the distance between consecutive 3-h GPS-relocations, of sub-adult cougars relative to different habitats, times of day and between transient and localizing behavior. All individual sub-adult cougars displayed bouts of transient and localizing behavior. All male cougars dispersed from their natal ranges and travelled considerably farther distances than female cougars. One male dispersed over 750 km eastward through the agricultural belt of northern Montana and southern Saskatchewan. Males occupied temporary home ranges in more open habitats on the fringes of the insular Cypress Hills, while females appeared to be recruited into the adult population, occupying treed habitat that provided more suitable cover. During both ranging behaviors, sub-adult cougars selected for rugged terrain and proximity to hydrological features (likely supporting riparian habitats) and avoided open cover types. Differences in habitat selection between ranging

  3. Elucidating dynamic responses of North Pacific fish populations to climatic forcing: Influence of life-history strategy

    NASA Astrophysics Data System (ADS)

    Yatsu, A.; Aydin, K. Y.; King, J. R.; McFarlane, G. A.; Chiba, S.; Tadokoro, K.; Kaeriyama, M.; Watanabe, Y.

    2008-05-01

    In order to explore mechanistic linkages between low-frequency ocean/climate variability, and fish population responses, we undertook comparative studies of time-series of recruitment-related productivity and the biomass levels of fish stocks representing five life-history strategies in the northern North Pacific between the 1950s and the present. We selected seven species: Japanese sardine ( Sardinopus melanostictus) and California sardine ( Sardinopus sagax) (opportunistic strategists), walleye pollock ( Theragra chalcogramma, intermediate strategist), pink salmon ( Oncorhynchus gorbuscha, salmonic strategist), sablefish ( Anoplopoma fimbria) and Pacific halibut ( Hippoglossus stenolepis) (periodic strategists) and spiny dogfish ( Squalus acanthias, equilibrium strategist). The responses in terms of productivity of sardine, pink salmon, sablefish and halibut to climatic regime shifts were generally immediate, delayed, or no substantial responses depending on the particular regime shift year and fish stock (population). In walleye pollock, there were some periods of high productivity and low productivity, but not coincidental to climatic regime shifts, likely due to indirect climate forcing impacts on both bottom-up and top-down processes. Biomass of zooplankton and all fish stocks examined, except for spiny dogfish whose data were limited, indicated a decadal pattern with the most gradual changes in periodic strategists and most intensive and rapid changes in opportunistic strategists. Responses of sardine productivity to regime shifts were the most intense, probably due to the absence of density-dependent effects and the availability of refuges from predators when sardine biomass was extremely low. Spiny dogfish were least affected by environmental variability. Conversely, spiny dogfish are likely to withstand only modest harvest rates due to their very low intrinsic rate of increase. Thus, each life-history strategy type had a unique response to climatic

  4. Population and biological parameters of selected fish species from the middle Xingu River, Amazon Basin.

    PubMed

    Camargo, M; Giarrizzo, T; Isaac, V J

    2015-08-01

    This study estimates the main biological parameters, including growth rates, asymptotic length, mortality, consumption by biomass, biological yield, and biomass, for the most abundant fish species found on the middle Xingu River, prior to the construction of the Belo Monte Dam. The specimens collected in experimental catches were analysed with empirical equations and length-based FISAT methods. For the 63 fish species studied, high growth rates (K) and high natural mortality (M) were related to early sexual maturation and low longevity. The predominance of species with short life cycles and a reduced number of age classes, determines high rates of stock turnover, which indicates high productivity for fisheries, and a low risk of overfishing.

  5. Evaluation and management implications of uncertainty in a multispecies size-structured model of population and community responses to fishing.

    PubMed

    Thorpe, Robert B; Le Quesne, Will J F; Luxford, Fay; Collie, Jeremy S; Jennings, Simon

    2015-01-01

    Implementation of an ecosystem approach to fisheries requires advice on trade-offs among fished species and between fisheries yields and biodiversity or food web properties. However, the lack of explicit representation, analysis and consideration of uncertainty in most multispecies models has limited their application in analyses that could support management advice.We assessed the consequences of parameter uncertainty by developing 78 125 multispecies size-structured fish community models, with all combinations of parameters drawn from ranges that spanned parameter values estimated from data and literature. This unfiltered ensemble was reduced to 188 plausible models, the filtered ensemble (FE), by screening outputs against fish abundance data and ecological principles such as requiring species' persistence.Effects of parameter uncertainty on estimates of single-species management reference points for fishing mortality (FMSY, fishing mortality rate providing MSY, the maximum sustainable yield) and biomass (BMSY, biomass at MSY) were evaluated by calculating probability distributions of estimated reference points with the FE. There was a 50% probability that multispecies FMSY could be estimated to within ±25% of its actual value, and a 50% probability that BMSY could be estimated to within ±40% of its actual value.Signal-to-noise ratio was assessed for four community indicators when mortality rates were reduced from current rates to FMSY. The slope of the community size spectrum showed the greatest signal-to-noise ratio, indicating that it would be the most responsive indicator to the change in fishing mortality F. Further, the power of an ongoing international monitoring survey to detect predicted responses of size spectrum slope was higher than for other size-based metrics.Synthesis and applications: Application of the ensemble model approach allows explicit representation of parameter uncertainty and supports advice and management by (i) providing uncertainty

  6. Population Structure and Phylogeography in Nassau Grouper (Epinephelus striatus), a Mass-Aggregating Marine Fish

    PubMed Central

    Jackson, Alexis M.; Semmens, Brice X.; Sadovy de Mitcheson, Yvonne; Nemeth, Richard S.; Heppell, Scott A.; Bush, Phillippe G.; Aguilar-Perera, Alfonso; Claydon, John A. B.; Calosso, Marta C.; Sealey, Kathleen S.; Schärer, Michelle T.; Bernardi, Giacomo

    2014-01-01

    To address patterns of genetic connectivity in a mass-aggregating marine fish, we analyzed genetic variation in mitochondrial DNA (mtDNA), microsatellites, and single nucleotide polymorphisms (SNPs) for Nassau grouper (Epinephelus striatus). We expected Nassau grouper to exhibit genetic differentiation among its subpopulations due to its reproductive behavior and retentive oceanographic conditions experienced across the Caribbean basin. All samples were genotyped for two mitochondrial markers and 9 microsatellite loci, and a subset of samples were genotyped for 4,234 SNPs. We found evidence of genetic differentiation in a Caribbean-wide study of this mass-aggregating marine fish using mtDNA (FST = 0.206, p<0.001), microsatellites (FST = 0.002, p = 0.004) and SNPs (FST = 0.002, p = 0.014), and identified three potential barriers to larval dispersal. Genetically isolated regions identified in our work mirror those seen for other invertebrate and fish species in the Caribbean basin. Oceanographic regimes in the Caribbean may largely explain patterns of genetic differentiation among Nassau grouper subpopulations. Regional patterns observed warrant standardization of fisheries management and conservation initiatives among countries within genetically isolated regions. PMID:24830641

  7. Context dependency of trait repeatability and its relevance for management and conservation of fish populations

    PubMed Central

    Killen, S. S.; Adriaenssens, B.; Marras, S.; Claireaux, G.; Cooke, S. J.

    2016-01-01

    Repeatability of behavioural and physiological traits is increasingly a focus for animal researchers, for which fish have become important models. Almost all of this work has been done in the context of evolutionary ecology, with few explicit attempts to apply repeatability and context dependency of trait variation toward understanding conservation-related issues. Here, we review work examining the degree to which repeatability of traits (such as boldness, swimming performance, metabolic rate and stress responsiveness) is context dependent. We review methods for quantifying repeatability (distinguishing between within-context and across-context repeatability) and confounding factors that may be especially problematic when attempting to measure repeatability in wild fish. Environmental factors such temperature, food availability, oxygen availability, hypercapnia, flow regime and pollutants all appear to alter trait repeatability in fishes. This suggests that anthropogenic environmental change could alter evolutionary trajectories by changing which individuals achieve the greatest fitness in a given set of conditions. Gaining a greater understanding of these effects will be crucial for our ability to forecast the effects of gradual environmental change, such as climate change and ocean acidification, the study of which is currently limited by our ability to examine trait changes over relatively short time scales. Also discussed are situations in which recent advances in technologies associated with electronic tags (biotelemetry and biologging) and respirometry will help to facilitate increased quantification of repeatability for physiological and integrative traits, which so far lag behind measures of repeatability of behavioural traits. PMID:27382470

  8. Paleoecological studies on variability in marine fish populations: A long-term perspective on the impacts of climatic change on marine ecosystems

    NASA Astrophysics Data System (ADS)

    Finney, Bruce P.; Alheit, Jürgen; Emeis, Kay-Christian; Field, David B.; Gutiérrez, Dimitri; Struck, Ulrich

    2010-02-01

    The use of historical fishing records to understand relationships between climatic change and fish abundance is limited by the relatively short duration of these records, and complications due to the strong influence of human activity in addition to climatic change. Sedimentary records containing scales, bones or geochemical proxies of variability in fish populations provide unique insights on long-term ecosystem dynamics and relationships with climatic change. Available records from Holocene sediments are summarized and synthesized. The records are from several widespread locations near or along the continental margins of the South Atlantic and Pacific oceans, including Alaska, USA (Pacific salmon), Saanich and Effingham Inlets, British Columbia, Canada (pelagic fish), Santa Barbara Basin, California, USA (Northern anchovies and Pacific sardines), Gulf of California, Mexico (Pacific sardines, Northern anchovies and Pacific hake), Peru upwelling system (sardines, anchovies and hake), and Benguela Current System, South Africa (sardines, anchovies and hake). These records demonstrate that fish population sizes are not constant, and varied significantly over a range of time scales prior to the advent of large-scale commercial fishing. In addition to the decadal-scale variability commonly observed in historical records, the long-term records reveal substantial variability over centennial and millennial time scales. Shifts in abundance are often, but not always, correlated with regional and/or global climatic changes. The long-term perspective reveals different patterns of variability in fish populations, as well as fish-climate relationships, than suggested by analysis of historical records. Many records suggest prominent changes in fish abundance at ca. 1000-1200 AD, during the Little Ice Age, and during the transition at the end of the Little Ice Age in the 19th century that may be correlative, and that were likely driven by major hemispheric or global

  9. Multiple regression models of δ13C and δ15N for fish populations in the eastern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Radabaugh, Kara R.; Peebles, Ernst B.

    2014-08-01

    Multiple regression models were created to explain spatial and temporal variation in the δ13C and δ15N values of fish populations on the West Florida Shelf (eastern Gulf of Mexico, USA). Extensive trawl surveys from three time periods were used to acquire muscle samples from seven groundfish species. Isotopic variation (δ13Cvar and δ15Nvar) was calculated as the deviation from the isotopic mean of each fish species. Static spatial data and dynamic water quality parameters were used to create models predicting δ13Cvar and δ15Nvar in three fish species that were caught in the summers of 2009 and 2010. Additional data sets were then used to determine the accuracy of the models for predicting isotopic variation (1) in a different time period (fall 2010) and (2) among four entirely different fish species that were collected during summer 2009. The δ15Nvar model was relatively stable and could be applied to different time periods and species with similar accuracy (mean absolute errors 0.31-0.33‰). The δ13Cvar model had a lower predictive capability and mean absolute errors ranged from 0.42 to 0.48‰. δ15N trends are likely linked to gradients in nitrogen fixation and Mississippi River influence on the West Florida Shelf, while δ13C trends may be linked to changes in algal species, photosynthetic fractionation, and abundance of benthic vs. planktonic basal resources. These models of isotopic variability may be useful for future stable isotope investigations of trophic level, basal resource use, and animal migration on the West Florida Shelf.

  10. Effects of Low-Dose Aspirin and Fish Oil on Platelet Function and NF-kappaB in Adults with Diabetes Mellitus

    PubMed Central

    Block, Robert C; Abdolahi, Amir; Smith, Brian; Meednu, N; Thevenet-Morrison, Kelly; Cai, Xueya; Cui, Huadong; Mousa, Shaker; Brenna, J. Thomas; Georas, S

    2013-01-01

    SUMMARY Introduction Many diabetics are insensitive to aspirin’s platelet anti-aggregation effects. The possible modulating effects of coadministration of aspirin and fish oil in subjects with diabetes are poorly characterized. Participants and Methods Thirty adults with type 2 diabetes mellitus were treated with aspirin 81 mg/d for 7 days, then with fish oil 4g/day for 28 days, then the combination of fish oil and aspirin for another 7 days. Results Aspirin alone and in combination with fish oil reduced platelet aggregation in most participants. Five of 7 participants classified as aspirin insensitive 1 week after daily aspirin ingestion were sensitive after the combination. Although some platelet aggregation measures correlated positively after aspirin and fish oil ingestion alone and (in combination) in all individuals, correlation was only observed in those who were aspirin insensitive after ingestion of the combination. Conclusions Co-adminstration of aspirin and fish oil may reduce platelet aggregation more than aspirin alone in adults with diabetes mellitus. PMID:23664596

  11. Ice age fish in a warming world: minimal variation in thermal acclimation capacity among lake trout (Salvelinus namaycush) populations

    PubMed Central

    Kelly, Nicholas I.; Burness, Gary; McDermid, Jenni L.; Wilson, Chris C.

    2014-01-01

    In the face of climate change, the persistence of cold-adapted species will depend on their adaptive capacity for physiological traits within and among populations. The lake trout (Salvelinus namaycush) is a cold-adapted salmonid and a relict from the last ice age that is well suited as a model species for studying the predicted effects of climate change on coldwater fishes. We investigated the thermal acclimation capacity of upper temperature resistance and metabolism of lake trout from four populations across four acclimation temperatures. Individuals were reared from egg fertilization onward in a common environment and, at 2 years of age, were acclimated to 8, 11, 15 or 19°C. Although one population had a slightly higher maximal metabolic rate (MMR), higher metabolic scope for activity and faster metabolic recovery across all temperatures, there was no interpopulation variation for critical thermal maximum (CTM) or routine metabolic rate (RMR) or for the thermal acclimation capacity of CTM, RMR, MMR or metabolic scope. Across the four acclimation temperatures, there was a 3°C maximal increase in CTM and 3-fold increase in RMR for all populations. Above 15°C, a decline in MMR and increase in RMR resulted in sharply reduced metabolic scope for all populations acclimated at 19°C. Together, these data suggest there is limited variation among lake trout populations in thermal physiology or capacity for thermal acclimatization, and that climate change may impact lake trout populations in a similar manner across a wide geographical range. Understanding the effect of elevated temperatures on the thermal physiology of this economically and ecologically important cold-adapted species will help inform management and conservation strategies for the long-term sustainability of lake trout populations. PMID:27293646

  12. Population cage experiments with a vertebrate: The temporal demography and cytonuclear genetics of hybridization on Gambusia fishes

    USGS Publications Warehouse

    Scribner, Kim T.; Avise, John C.

    1994-01-01

    The dynamics of mitochondrial and multilocus nuclear genotypic frequencies were monitored for 2 yr in experimental populations established with equal numbers of two poeciliid fishes (Gambusia affinis and Gambusia holbrooki) that hybridize naturally in the southeastern United States. In replicated "small-pool" populations (experiment I), 1018 sampled individuals at six time periods revealed an initial flush of hybridization, followed by a rapid decline in frequencies of G. affinis nuclear and mitochondrial alleles over 64 wk. Decay of gametic and cytonuclear disequilibria differed from expectations under random mating as well as under a model of assortative mating involving empirically estimated mating propensities. In two replicate "large-pond" populations (experiment II), 841 sampled individuals across four reproductive cohorts revealed lower initial frequencies of F1 hybrids than in experiment I, but again G. holbrooki alleles achieved high frequencies over four generations (72 wk). Thus, evolution within experimental Gambusia hybrid populations can be extremely rapid, resulting in consistent loss of G. affinis nuclear and cytoplasmic alleles. Concordance in results between experiments and across genetic markers suggests strong directional selection favoring G. holbrooki genotypes. Results are interpreted in light of previous reports of genotype-specific differences in life-history traits, reproductive ecology, patterns of recruitment, and size-specific mortality, and in the context of patterns of introgression previously studied indirectly from spatial observations on cytonuclear genotypes in natural Gambusia populations.

  13. Adult Vampire Bats Produce Contact Calls When Isolated: Acoustic Variation by Species, Population, Colony, and Individual

    PubMed Central

    Carter, Gerald G.; Logsdon, Ryane; Arnold, Bryan D.; Menchaca, Angelica; Medellin, Rodrigo A.

    2012-01-01

    Background Bat pups produce individually distinct isolation calls to facilitate maternal recognition. Increasing evidence suggests that, in group-living bat species, adults often use similar calls to maintain contact. We investigated if isolated adults from all three species of the highly cooperative vampire bats (Phyllostomidae: Desmodontinae) would produce vocally distinct contact calls when physically isolated. Methods/Principal Findings We assessed variation in contact calls recorded from isolated captive and wild-caught adult common vampire bats (Desmodus rotundus), white-winged vampire bats (Diaemus youngi) and hairy-legged vampire bats (Diphylla ecaudata). We compared species-typical contact call structure, and used information theory and permuted discriminate function analyses to examine call structure variation, and to determine if the individuality of contact calls is encoded by different call features across species and populations. We found that isolated adult vampire bats produce contact calls that vary by species, population, colony, and individual. However, much variation occurred within a single context and individual. We estimated signature information for captive Diaemus (same colony), captive Desmodus (same colony), and wild Desmodus (different colonies) at 3.21, 3.26, and 3.88 bits, respectively. Contact calls from a captive colony of Desmodus were less individually distinct than calls from wild-caught Desmodus from different colonies. Both the degree of individuality and parameters encoding individuality differed between the bats from a single captive colony and the wild-caught individuals from different groups. This result is consistent with, but not sufficient evidence of, vocal convergence in groups. Conclusion Our results show that adult vampire bats of all three species produce highly variable contact calls when isolated. Contact calls contain sufficient information for vocal discrimination, but also possess more intra-individual variation

  14. Population Dynamics of Adult Lost River (Deltistes luxatus) and Shortnose (Chasmistes brevirostris) Suckers in Clear Lake Reservoir, California, 2006-08

    USGS Publications Warehouse

    Barry, Patrick M.; Janney, Eric C.; Hewitt, David A.; Hayes, Brian S.; Scott, Alta C.

    2009-01-01

    of Lost River suckers detected in Willow Creek was skewed toward males, despite consistently more females having been tagged in fall sampling. This pattern indicates that some tagged female Lost River suckers may be spawning elsewhere in the system, and we intend to investigate this possibility to verify or alter the representativeness of our spring monitoring. Length frequency analysis of fall trammel net catches showed that the populations of both species in Clear Lake Reservoir have undergone major demographic transitions during the last 15 years. In the mid-1990s, the populations were dominated by larger fish and showed little evidence of recent recruitment. These larger fish apparently disappeared in the late 1990s and early 2000s, and the populations are now dominated by fish that recruited into the adult populations in the late 1990s. The length frequencies from the last 4 years provide evidence of consistent recruitment into the Lost River sucker population, but provide no such evidence for the shortnose sucker population. Overall, annual growth rates for both species in Clear Lake were 2-4 times greater than growth rates for conspecifics in Upper Klamath Lake. However, little or no growth occurred for either species in Clear Lake between 2006 and 2007. Based on available evidence, we are unable to fully explain differences in growth rates between systems or among years within Clear Lake.

  15. Colour-assortative mating among populations of Tropheus moorii, a cichlid fish from Lake Tanganyika, East Africa.

    PubMed

    Salzburger, Walter; Niederstätter, Harald; Brandstätter, Anita; Berger, Burkhard; Parson, Walther; Snoeks, Jos; Sturmbauer, Christian

    2006-02-07

    The species flocks of cichlid fishes in the East African Lakes Tanganyika, Malawi and Victoria are prime examples of adaptive radiation and explosive speciation. Several hundreds of endemic species have evolved in each of the lakes over the past several thousands to a few millions years. Sexual selection via colour-assortative mating has often been proposed as a probable causal factor for initiating and maintaining reproductive isolation. Here, we report the consequences of human-mediated admixis among differentially coloured populations of the endemic cichlid fish Tropheus moorii from several localities that have accidentally been put in sympatry in a small harbour bay in the very south of Lake Tanganyika. We analysed the phenotypes (coloration) and genotypes (mitochondrial control region and five microsatellite loci) of almost 500 individuals, sampled over 3 consecutive years. Maximum-likelihood-based parenthood analyses and Bayesian inference of population structure revealed that significantly more juveniles are the product of within-colour-morph matings than could be expected under the assumption of random mating. Our results clearly indicate a marked degree of assortative mating with respect to the different colour morphs. Therefore, we postulate that sexual selection based on social interactions and female mate choice has played an important role in the formation and maintenance of the different colour morphs in Tropheus, and is probably common in other maternally mouthbrooding cichlids as well.

  16. Heterogeneity of HIV incidence: a comparative analysis between fishing communities and in a neighbouring rural general population, Uganda, and implications for HIV control

    PubMed Central

    Kamali, A; Nsubuga, R N; Ruzagira, E; Bahemuka, U; Asiki, G; Price, M A; Newton, R; Kaleebu, P; Fast, P

    2016-01-01

    Objectives To describe HIV heterogeneity in rural Uganda using incidence data collected between January 2012 and December 2014 among fishing cohort (FC) and in an adjacent rural general population cohort (GPC). Methods In the FC, eligible HIV high-risk adults aged 18+ years were enrolled, followed and HIV tested every 3 months. Demographic and sexual behaviour data were also collected. The GPC, approximately 47 km away from the FC, was followed through annual surveys, and sociodemographic and behavioural data collected. A subset of GPC with comparable risk profiles to the FC was selected. We presented sociodemographic and risk profiles and also computed stratified HIV incidence. Cox regression was used to assess factors associated with HIV incidence. Results Overall HIV incidence was higher in the FC than in the ‘high-risk’ GPC, 6.04 and 0.56 per 100 person years at risk, respectively, with a rate ratio (RR) of 10.83 (95% CI 6.11 to 19.76). This was higher among those aged 18–24 years, unmarried and those with more than two sex partners in the past year, RR of 15.44, 22.99 and 19.29, respectively. In the FC, factors associated with high incidence in multivariate analysis were duration in the community and unprotected sex. The factors in the GPC were ethnicity, marital status and duration in the community. Conclusions We have observed a substantial heterogeneity in HIV incidence. The high incidence in fishing communities is contributing greatly to the overall HIV burden in Uganda, and thus urgent combination prevention efforts are needed towards national goal to reduce HIV epidemic. PMID:26933046

  17. Intraspecific genetic admixture and the morphological diversification of an estuarine fish population complex.

    PubMed

    Dodson, Julian J; Bourret, Audrey; Barrette, Marie France; Turgeon, Julie; Daigle, Gaétan; Legault, Michel; Lecomte, Frédéric

    2015-01-01

    The North-east American Rainbow smelt (Osmerus mordax) is composed of two glacial races first identified through the spatial distribution of two distinct mtDNA lineages. Contemporary breeding populations of smelt in the St. Lawrence estuary comprise contrasting mixtures of both lineages, suggesting that the two races came into secondary contact in this estuary. The overall objective of this study was to assess the role of intraspecific genetic admixture in the morphological diversification of the estuarine rainbow smelt population complex. The morphology of mixed-ancestry populations varied as a function of the relative contribution of the two races to estuarine populations, supporting the hypothesis of genetic admixture. Populations comprising both ancestral mtDNA races did not exhibit intermediate morphologies relative to pure populations but rather exhibited many traits that exceeded the parental trait values, consistent with the hypothesis of transgressive segregation. Evidence for genetic admixture at the level of the nuclear gene pool, however, provided only partial support for this hypothesis. Variation at nuclear AFLP markers revealed clear evidence of the two corresponding mtDNA glacial races. The admixture of the two races at the nuclear level is only pronounced in mixed-ancestry populations dominated by one of the mtDNA lineages, the same populations showing the greatest degree of morphological diversification and population structure. In contrast, mixed-ancestry populations dominated by the alternate mtDNA lineage showed little evidence of introgression of the nuclear genome, little morphological diversification and little contemporary population genetic structure. These results only partially support the hypothesis of transgressive segregation and may be the result of the differential effects of natural selection acting on admixed genomes from different sources.

  18. Intraspecific Genetic Admixture and the Morphological Diversification of an Estuarine Fish Population Complex

    PubMed Central

    Legault, Michel

    2015-01-01

    The North-east American Rainbow smelt (Osmerus mordax) is composed of two glacial races first identified through the spatial distribution of two distinct mtDNA lineages. Contemporary breeding populations of smelt in the St. Lawrence estuary comprise contrasting mixtures of both lineages, suggesting that the two races came into secondary contact in this estuary. The overall objective of this study was to assess the role of intraspecific genetic admixture in the morphological diversification of the estuarine rainbow smelt population complex. The morphology of mixed-ancestry populations varied as a function of the relative contribution of the two races to estuarine populations, supporting the hypothesis of genetic admixture. Populations comprising both ancestral mtDNA races did not exhibit intermediate morphologies relative to pure populations but rather exhibited many traits that exceeded the parental trait values, consistent with the hypothesis of transgressive segregation. Evidence for genetic admixture at the level of the nuclear gene pool, however, provided only partial support for this hypothesis. Variation at nuclear AFLP markers revealed clear evidence of the two corresponding mtDNA glacial races. The admixture of the two races at the nuclear level is only pronounced in mixed-ancestry populations dominated by one of the mtDNA lineages, the same populations showing the greatest degree of morphological diversification and population structure. In contrast, mixed-ancestry populations dominated by the alternate mtDNA lineage showed little evidence of introgression of the nuclear genome, little morphological diversification and little contemporary population genetic structure. These results only partially support the hypothesis of transgressive segregation and may be the result of the differential effects of natural selection acting on admixed genomes from different sources. PMID:25856193

  19. Anatomical variation of posterior slope of tibial plateau in adult Eastern Indian population

    PubMed Central

    Medda, Shyamalendu; Kundu, Rajib; Sengupta, Sohini; Pal, Ananda Kisor

    2017-01-01

    Background: Upper surface of the proximal tibial end, tibial plateau, has a slope directed posteroinferiorly relative to the long axis of the middle of the shaft. It has important consideration in surgeries such as knee arthroplasty, high tibial osteotomy, and medical imaging of the knee joint. The aim of the present study was to estimate the tibial plateau angle (TPA) by plain radiograph in the adult Eastern Indian population as during literature review, we were unable to find any study, except one (without specific reference axis), on this variable among the Indian population. Materials and Methods: A sample was taken from adult patients attending the outpatient department of orthopedics of the institute with minor knee problems. Measurement of the TPA was done in the true lateral radiographs of the knee joints of the selected subjects by a standardized method. Results: TPA varied widely from 6° to 24°, with the mean ± standard deviation value 13.6° ±3.5°. Student's unpaired t-test revealed no significant difference of TPA between left and right knees, both in male (P = 0.748) and female (P = 0.917) separately and in the entire study population irrespective of gender (P = 0.768). Comparison of TPA between male (13.3° ± 3.3°) and female (13.9° ± 3.4°) by Student's unpaired t-test showed no sexual dimorphism (P = 0.248). There were poor correlations of TPA with age and body mass index. Conclusion: The present study described the variations of the TPA in the adult Eastern Indian population (range 6°–24°, mean ± SD 13.6° ± 3.5°, no laterality, no sexual dimorphism, poor correlation with age and BMI). Knowledge of this study could be used in different orthopedic surgeries and imaging technique in or around the knee joint. PMID:28216753

  20. Effects of Changes in Food Supply at the Time of Sex Differentiation on the Gonadal Transcriptome of Juvenile Fish. Implications for Natural and Farmed Populations

    PubMed Central

    Díaz, Noelia; Ribas, Laia; Piferrer, Francesc

    2014-01-01

    Background Food supply is a major factor influencing growth rates in animals. This has important implications for both natural and farmed fish populations, since food restriction may difficult reproduction. However, a study on the effects of food supply on the development of juvenile gonads has never been transcriptionally described in fish. Methods and Findings This study investigated the consequences of growth on gonadal transcriptome of European sea bass in: 1) 4-month-old sexually undifferentiated fish, comparing the gonads of fish with the highest vs. the lowest growth, to explore a possible link between transcriptome and future sex, and 2) testis from 11-month-old juveniles where growth had been manipulated through changes in food supply. The four groups used were: i) sustained fast growth, ii) sustained slow growth, iii) accelerated growth, iv) decelerated growth. The transcriptome of undifferentiated gonads was not drastically affected by initial natural differences in growth. Further, changes in the expression of genes associated with protein turnover were seen, favoring catabolism in slow-growing fish and anabolism in fast-growing fish. Moreover, while fast-growing fish took energy from glucose, as deduced from the pathways affected and the analysis of protein-protein interactions examined, in slow-growing fish lipid metabolism and gluconeogenesis was favored. Interestingly, the highest transcriptomic differences were found when forcing initially fast-growing fish to decelerate their growth, while accelerating growth of initially slow-growing fish resulted in full transcriptomic convergence with sustained fast-growing fish. Conclusions Food availability during sex differentiation shapes the juvenile testis transcriptome, as evidenced by adaptations to different energy balances. Remarkably, this occurs in absence of major histological changes in the testis. Thus, fish are able to recover transcriptionally their testes if they are provided with enough food

  1. Strong population genetic structuring in an annual fish, Nothobranchius furzeri, suggests multiple savannah refugia in southern Mozambique

    PubMed Central

    2013-01-01

    Background Intraspecific genetic variation of African fauna has been significantly affected by pronounced climatic fluctuations in Plio-Pleistocene, but, with the exception of large mammals, very limited empirical data on diversity of natural populations are available for savanna-dwelling animals. Nothobranchius furzeri is an annual fish from south-eastern Africa, inhabiting discrete temporary savannah pools outside main river alluvia. Their dispersal is limited and population processes affecting its genetic structure are likely a combination of those affecting terrestrial and aquatic taxa. N. furzeri is a model taxon in ageing research and several populations of known geographical origin are used in laboratory studies. Here, we analysed the genetic structure, diversity, historical demography and temporal patterns of divergence in natural populations of N. furzeri across its entire distribution range. Results Genetic structure and historical demography of N. furzeri were analysed using a combination of mitochondrial (partial cytochrome b sequences, 687 bp) and nuclear (13 microsatellites) markers in 693 fish from 36 populations. Genetic markers consistently demonstrated strong population structuring and suggested two main genetic groups associated with river basins. The split was dated to the Pliocene (>2 Mya). The northern group inhabits savannah pools across the basin of the intermittent river Chefu in south-western Mozambique and eastern Zimbabwe. The southern group (from southernmost Mozambique) is subdivided, with the River Limpopo forming a barrier (maximum divergence time 1 Mya). A strong habitat fragmentation (isolated temporary pools) is reflected in significant genetic structuring even between adjacent pools, with a major influence of genetic drift and significant isolation-by-distance. Analysis of historical demography revealed that the expansion of both groups is ongoing, supported by frequent founder effects in marginal parts of the range and evidence

  2. The reproductive hormone cycle of adult female American alligators from a barrier island population.

    PubMed

    Hamlin, Heather J; Lowers, Russell H; Kohno, Satomi; Mitsui-Watanabe, Naoko; Amano, Haruna; Hara, Akihiko; Ohta, Yasuhiko; Miyagawa, Shinichi; Iguchi, Taisen; Guillette, Louis J

    2014-06-01

    Comparatively, little data are available detailing the geographic variation that exists in the reproductive endocrinology of adult alligators, especially those living in barrier islands. The Merritt Island National Wildlife Refuge (MI) is a unique barrier island environment and home to the Kennedy Space Center (FL, USA). Seasonal patterns of sex steroids were assessed in adult female American alligators from MI monthly from 2008 to 2009, with additional samples collected at more random intervals in 2006, 2007, and 2010. Plasma 17β-estradiol and vitellogenin concentrations peaked in April, coincident with courtship and mating, and showed patterns similar to those observed in adult female alligators in other regions. Plasma concentrations of progesterone, however, showed patterns distinctly different than those reported for alligator populations in other regions and remained relatively constant throughout the year. Plasma DHEA peaked in July around the time of oviposition, decreased in August, and then remained constant for the remaining months, except for a moderate increase in October. Circulating concentrations of DHEA have not been previously assessed in a female crocodilian, and plasma concentrations coincident with reproductive activity suggest a reproductive and/or behavioral role. Interestingly, plasma testosterone concentrations peaked in May of 2008, as has been shown in female alligator populations in other regions, but showed no peak in 2009, demonstrating dramatic variability from year to year. Surveys showed 2009 to be particularly depauperate of alligator nests in MI, and it is possible that testosterone could serve as a strong indicator of breeding success.

  3. Use of Population Modeling to Enhance the Gulf Sturgeon Recovery Plan

    DTIC Science & Technology

    1998-04-01

    The estimated population sire iii 1996 was approximately 300 fish with adults comprising about 3 percent of the population. Annual mortality rates in... mortality rates in the range of 13 to 18 percent, depending upon recruitment assumptions. Population models indicated that catch and fishing effort

  4. Impacts of golden alga Prymnesium parvum on fish populations in reservoirs of the upper Colorado River and Brazos River basins, Texas

    USGS Publications Warehouse

    VanLandeghem, Matthew M.; Farooqi, Mukhtar; Farquhar, B.; Patino, Reynaldo

    2013-01-01

    Several reservoirs in the upper Colorado River and Brazos River basins in Texas have experienced toxic blooms of golden alga Prymnesium parvum and associated fish kills since 2001. There is a paucity of information, however, regarding the population-level effects of such kills in large reservoirs, species-specific resistance to or recovery from kills, or potential differences in the patterns of impacts among basins. We used multiple before-after, control-impact analysis to determine whether repeated golden alga blooms have led to declines in the relative abundance and size structure of fish populations. Sustained declines were noted for 9 of 12 fish species surveyed in the upper Colorado River, whereas only one of eight species was impacted by golden alga in the Brazos River. In the upper Colorado River, White Bass Morone chrysops, White Crappie Pomoxis annularis, Largemouth Bass Micropterus salmoides, Bluegill Lepomis macrochirus, River Carpsucker Carpiodes carpio, Freshwater Drum Aplodinotus grunniens, Channel Catfish Ictalurus punctatus, Flathead Catfish Pylodictis olivaris, and Blue Catfish I. furcatus exhibited sustained declines in relative abundance, size structure, or both; Gizzard Shad Dorosoma cepedianum, Longnose Gar Lepisosteus osseus, and Common Carp Cyprinus carpio did not exhibit those declines. In the Brazos River, only the relative abundance of Blue Catfish was impacted. Overall, toxic golden alga blooms can negatively impact fish populations over the long-term, but the patterns of impact can vary considerably among river basins and species. In the Brazos River, populations of most fish species appear to be healthy, suggesting a positive angling outlook for this basin. In the upper Colorado River, fish populations have been severely impacted, and angling opportunities have been reduced. Basin-specific management plans aimed at improving water quality and quantity will likely reduce bloom intensity and allow recovery of fish populations to the

  5. A Review of Dietary Surveys in the Adult South African Population from 2000 to 2015.

    PubMed

    Mchiza, Zandile J; Steyn, Nelia P; Hill, Jillian; Kruger, Annamarie; Schönfeldt, Hettie; Nel, Johanna; Wentzel-Viljoen, Edelweiss

    2015-09-23

    One serious concern of health policymakers in South Africa is the fact that there is no national data on the dietary intake of adult South Africans. The only national dietary study was done in children in 1999. Hence, it becomes difficult to plan intervention and strategies to combat malnutrition without national data on adults. The current review consequently assessed all dietary studies in adults from 2000 to June 2015 in an attempt to portray typical adult dietary intakes and to assess possible dietary deficiencies. Notable findings were that, in South Africa micronutrient deficiencies are still highly prevalent and energy intakes varied between very low intakes in informal settlements to very high intakes in urban centers. The most commonly deficient food groups observed are fruit and vegetables, and dairy. This has been attributed to high prices and lack of availability of these food groups in poorer urban areas and townships. In rural areas, access to healthy foods also remains a problem. A national nutrition monitoring system is recommended in order to identify dietary deficiencies in specific population groups.

  6. A Review of Dietary Surveys in the Adult South African Population from 2000 to 2015

    PubMed Central

    Mchiza, Zandile J.; Steyn, Nelia P.; Hill, Jillian; Kruger, Annamarie; Schönfeldt, Hettie; Nel, Johanna; Wentzel-Viljoen, Edelweiss

    2015-01-01

    One serious concern of health policymakers in South Africa is the fact that there is no national data on the dietary intake of adult South Africans. The only national dietary study was done in children in 1999. Hence, it becomes difficult to plan intervention and strategies to combat malnutrition without national data on adults. The current review consequently assessed all dietary studies in adults from 2000 to June 2015 in an attempt to portray typical adult dietary intakes and to assess possible dietary deficiencies. Notable findings were that, in South Africa micronutrient deficiencies are still highly prevalent and energy intakes varied between very low intakes in informal settlements to very high intakes in urban centers. The most commonly deficient food groups observed are fruit and vegetables, and dairy. This has been attributed to high prices and lack of availability of these food groups in poorer urban areas and townships. In rural areas, access to healthy foods also remains a problem. A national nutrition monitoring system is recommended in order to identify dietary deficiencies in specific population groups. PMID:26404371

  7. Genetic architecture differences between pediatric and adult-onset inflammatory bowel diseases in the Polish population

    PubMed Central

    Ostrowski, Jerzy; Paziewska, Agnieszka; Lazowska, Izabella; Ambrozkiewicz, Filip; Goryca, Krzysztof; Kulecka, Maria; Rawa, Tomasz; Karczmarski, Jakub; Dabrowska, Michalina; Zeber-Lubecka, Natalia; Tomecki, Roman; Kluska, Anna; Balabas, Aneta; Piatkowska, Magdalena; Paczkowska, Katarzyna; Kierkus, Jaroslaw; Socha, Piotr; Lodyga, Michal; Rydzewska, Grazyna; Klopocka, Maria; Mierzwa, Grazyna; Iwanczak, Barbara; Krzesiek, Elzbieta; Bak-Drabik, Katarzyna; Walkowiak, Jaroslaw; Klincewicz, Beata; Radwan, Piotr; Grzybowska-Chlebowczyk, Urszula; Landowski, Piotr; Jankowska, Agnieszka; Korczowski, Bartosz; Starzynska, Teresa; Albrecht, Piotr; Mikula, Michal

    2016-01-01

    Most inflammatory bowel diseases (IBDs) are classic complex disorders represented by common alleles. Here we aimed to define the genetic architecture of pediatric and adult-onset IBDs for the Polish population. A total of 1495 patients were recruited, including 761 patients with Crohn’s disease (CD; 424 pediatric), 734 patients with ulcerative colitis (UC; 390 pediatric), and 934 healthy controls. Allelotyping employed a pooled-DNA genome-wide association study (GWAS) and was validated by individual genotyping. Whole exome sequencing (WES) was performed on 44 IBD patients diagnosed before 6 years of age, 45 patients diagnosed after 40 years of age, and 18 healthy controls. Altogether, out of 88 selected SNPs, 31 SNPs were replicated for association with IBD. A novel BRD2 (rs1049526) association reached significance of P = 5.2 × 10−11 and odds ratio (OR) = 2.43. Twenty SNPs were shared between pediatric and adult patients; 1 and 7 were unique to adult-onset and pediatric-onset IBD, respectively. WES identified numerous rare and potentially deleterious variants in IBD-associated or innate immunity-associated genes. Deleterious alleles in both groups were over-represented among rare variants in affected children. Our GWAS revealed differences in the polygenic architecture of pediatric- and adult-onset IBD. A significant accumulation of rare and deleterious variants in affected children suggests a contribution by yet unexplained genetic components. PMID:28008999

  8. Does covering of farm-associated Culicoides larval