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Sample records for abundant fish species

  1. Target strengths of two abundant mesopelagic fish species.

    PubMed

    Scoulding, Ben; Chu, Dezhang; Ona, Egil; Fernandes, Paul G

    2015-02-01

    Mesopelagic fish of the Myctophidae and Sternoptychidae families dominate the biomass of the oceanic deep scattering layers and, therefore, have important ecological roles within these ecosystems. Interest in the commercial exploitation of these fish is growing, so the development of techniques for estimating their abundance, distribution and, ultimately, sustainable exploitation are essential. The acoustic backscattering characteristics for two size classes of Maurolicus muelleri and Benthosema glaciale are reported here based on swimbladder morphology derived from digitized soft x-ray images, and empirical (in situ) measurements of target strength (TS) derived from an acoustic survey in a Norwegian Sea. A backscattering model based on a gas-filled prolate spheroid was used to predict the theoretical TS for both species across a frequency range between 0 and 250 kHz. Sensitivity analyses of the TS model to the modeling parameters indicate that TS is rather sensitive to the viscosity, swimbladder volume ratio, and tilt, which can result in substantial changes to the TS. Theoretical TS predictions close to the resonance frequency were in good agreement (±2 dB) with mean in situ TS derived from the areas acoustically surveyed that were spatially and temporally consistent with the trawl information for both species. PMID:25698030

  2. Fish and Phytoplankton Exhibit Contrasting Temporal Species Abundance Patterns in a Dynamic North Temperate Lake

    PubMed Central

    Hansen, Gretchen J. A.; Carey, Cayelan C.

    2015-01-01

    Temporal patterns of species abundance, although less well-studied than spatial patterns, provide valuable insight to the processes governing community assembly. We compared temporal abundance distributions of two communities, phytoplankton and fish, in a north temperate lake. We used both 17 years of observed relative abundance data as well as resampled data from Monte Carlo simulations to account for the possible effects of non-detection of rare species. Similar to what has been found in other communities, phytoplankton and fish species that appeared more frequently were generally more abundant than rare species. However, neither community exhibited two distinct groups of “core” (common occurrence and high abundance) and “occasional” (rare occurrence and low abundance) species. Both observed and resampled data show that the phytoplankton community was dominated by occasional species appearing in only one year that exhibited large variation in their abundances, while the fish community was dominated by core species occurring in all 17 years at high abundances. We hypothesize that the life-history traits that enable phytoplankton to persist in highly dynamic environments may result in communities dominated by occasional species capable of reaching high abundances when conditions allow. Conversely, longer turnover times and broad environmental tolerances of fish may result in communities dominated by core species structured primarily by competitive interactions. PMID:25651399

  3. Fish and phytoplankton exhibit contrasting temporal species abundance patterns in a dynamic north temperate lake.

    PubMed

    Hansen, Gretchen J A; Carey, Cayelan C

    2015-01-01

    Temporal patterns of species abundance, although less well-studied than spatial patterns, provide valuable insight to the processes governing community assembly. We compared temporal abundance distributions of two communities, phytoplankton and fish, in a north temperate lake. We used both 17 years of observed relative abundance data as well as resampled data from Monte Carlo simulations to account for the possible effects of non-detection of rare species. Similar to what has been found in other communities, phytoplankton and fish species that appeared more frequently were generally more abundant than rare species. However, neither community exhibited two distinct groups of "core" (common occurrence and high abundance) and "occasional" (rare occurrence and low abundance) species. Both observed and resampled data show that the phytoplankton community was dominated by occasional species appearing in only one year that exhibited large variation in their abundances, while the fish community was dominated by core species occurring in all 17 years at high abundances. We hypothesize that the life-history traits that enable phytoplankton to persist in highly dynamic environments may result in communities dominated by occasional species capable of reaching high abundances when conditions allow. Conversely, longer turnover times and broad environmental tolerances of fish may result in communities dominated by core species structured primarily by competitive interactions. PMID:25651399

  4. Temporal comparison and predictors of fish species abundance and richness on undisturbed coral reef patches

    PubMed Central

    Wismer, Sharon; Bshary, Redouan

    2015-01-01

    Large disturbances can cause rapid degradation of coral reef communities, but what baseline changes in species assemblages occur on undisturbed reefs through time? We surveyed live coral cover, reef fish abundance and fish species richness in 1997 and again in 2007 on 47 fringing patch reefs of varying size and depth at Mersa Bareika, Ras Mohammed National Park, Egypt. No major human or natural disturbance event occurred between these two survey periods in this remote protected area. In the absence of large disturbances, we found that live coral cover, reef fish abundance and fish species richness did not differ in 1997 compared to 2007. Fish abundance and species richness on patches was largely related to the presence of shelters (caves and/or holes), live coral cover and patch size (volume). The presence of the ectoparasite-eating cleaner wrasse, Labroides dimidiatus, was also positively related to fish species richness. Our results underscore the importance of physical reef characteristics, such as patch size and shelter availability, in addition to biotic characteristics, such as live coral cover and cleaner wrasse abundance, in supporting reef fish species richness and abundance through time in a relatively undisturbed and understudied region. PMID:26644988

  5. Temporal comparison and predictors of fish species abundance and richness on undisturbed coral reef patches.

    PubMed

    Wagner, Elena L E S; Roche, Dominique G; Binning, Sandra A; Wismer, Sharon; Bshary, Redouan

    2015-01-01

    Large disturbances can cause rapid degradation of coral reef communities, but what baseline changes in species assemblages occur on undisturbed reefs through time? We surveyed live coral cover, reef fish abundance and fish species richness in 1997 and again in 2007 on 47 fringing patch reefs of varying size and depth at Mersa Bareika, Ras Mohammed National Park, Egypt. No major human or natural disturbance event occurred between these two survey periods in this remote protected area. In the absence of large disturbances, we found that live coral cover, reef fish abundance and fish species richness did not differ in 1997 compared to 2007. Fish abundance and species richness on patches was largely related to the presence of shelters (caves and/or holes), live coral cover and patch size (volume). The presence of the ectoparasite-eating cleaner wrasse, Labroides dimidiatus, was also positively related to fish species richness. Our results underscore the importance of physical reef characteristics, such as patch size and shelter availability, in addition to biotic characteristics, such as live coral cover and cleaner wrasse abundance, in supporting reef fish species richness and abundance through time in a relatively undisturbed and understudied region. PMID:26644988

  6. Predators reduce abundance and species richness of coral reef fish recruits via non-selective predation

    NASA Astrophysics Data System (ADS)

    Heinlein, J. M.; Stier, A. C.; Steele, M. A.

    2010-06-01

    Predators have important effects on coral reef fish populations, but their effects on community structure have only recently been investigated and are not yet well understood. Here, the effect of predation on the diversity and abundance of young coral reef fishes was experimentally examined in Moorea, French Polynesia. Effects of predators were quantified by monitoring recruitment of fishes onto standardized patch reefs in predator-exclosure cages or uncaged reefs. At the end of the 54-day experiment, recruits were 74% less abundant on reefs exposed to predators than on caged ones, and species richness was 42% lower on reefs exposed to predators. Effects of predators varied somewhat among families, however, rarefaction analysis indicated that predators foraged non-selectively among species. These results indicate that predation can alter diversity of reef fish communities by indiscriminately reducing the abundance of fishes soon after settlement, thereby reducing the number of species present on reefs.

  7. Spatial predictability of juvenile fish species richness and abundance in a coral reef environment

    NASA Astrophysics Data System (ADS)

    Mellin, C.; Andréfouët, S.; Ponton, D.

    2007-12-01

    Juvenile reef fish communities represent an essential component of coral reef ecosystems in the current focus of fish population dynamics and coral reef resilience. Juvenile fish survival depends on habitat characteristics and is, following settlement, the first determinant of the number of individuals within adult populations. The goal of this study was to provide methods for mapping juvenile fish species richness and abundance into spatial domains suitable for micro and meso-scale analysis and management decisions. Generalized Linear Models predicting juvenile fish species richness and abundance were developed according to spatial and temporal environmental variables measured from 10 m up to 10 km in the southwest lagoon of New Caledonia. The statistical model was further spatially generalized using a 1.5-m resolution, independently created, remotely sensed, habitat map. This procedure revealed that : (1) spatial factors at 10 to 100-m scale explained up to 71% of variability in juvenile species richness, (2) a small improvement (75%) was gained when a combination of environmental variables at different spatial and temporal scales was used and (3) the coupling of remotely sensed data, geographical information system tools and point-based ecological data showed that the highest species richness and abundance were predicted along a narrow margin overlapping the coral reef flat and adjacent seagrass beds. Spatially explicit models of species distribution may be relevant for the management of reef communities when strong relationships exist between faunistic and environmental variables and when models are built at appropriate scales.

  8. The fish fauna of Anambra river basin, Nigeria: species abundance and morphometry.

    PubMed

    Odo, Gregory Ejikeme; Didigwu, Nwani Christopher; Eyo, Joseph Effiong

    2009-01-01

    The fish yields of most Nigeria inland waters are generally on the decline for causes that may range from inadequate management of the fisheries to degradation of the water bodies. Sustainable exploitation requires knowledge of the ichthyofaunal composition in the water bodies. We did a survey of fish species in Anambra river basin for 22 months. Fish samples were collected using four different gears -hook and line of size 13, caste nets, gill nets, and cages of mesh sizes of 50 mm, 75 mm, and 100 mm each. We recorded 52 fish species belonging to 17 families: 171, 236, and 169 individuals at Ogurugu, Otuocha, and Nsugbe stations respectively. Two families, Characidae, 19.5%, and Mochokidae, 11.8%, constituted the dominant fish families in the river. The dominant fish species were Citherinus citherius, 9.02%, and Alestes nurse, 7.1%. Other fish species with significant abundance were Synodontis clarias 6.9%, Macrolepidotus curvier 5.7%, Labeo coubie 5.4%, Distichodus rostrtus 4.9%, and Schilbe mystus 4.5%. The meristic features of the two most abundant fish species caught are as follows: Citharinus citharius dorsal fins 20, anal fins 30, caudal fins 21, pectoral fins, 9 and 8 ventral fins, and Alestes nurse 10 dorsal fins, 14 anal fins, 31 caudal fins, 7 pectoral fins and 6 ventral fins. The morphometric features of the two most abundant fish species are Citharinus citharius total length 300 mm, standard length 231 mm, head length 69 mm, body length 101 mm, body girth 176 mm, body weight 900 mg. Alestes nurse total length 200, standard length 140 mm, head length 60 mm, body length 80 mm, body girth 120 mm, body weight 400 mg. The most abundant animal utilizing the basin was Ardea cinerea (D3) with 22.2% occurrence (D4) and this was followed by Caprini with 13.51%, and Varanus niloticus, 10.04%. The least abundant animals utilizing basin were Chephalophus rufilatus, and Erythrocebus patas, with 0.58% each of occurrence. PMID:19637699

  9. Are the Most Plastic Species the Most Abundant Ones? An Assessment Using a Fish Assemblage

    PubMed Central

    Vidal, Nicolás; Zaldúa, Natalia; D'Anatro, Alejandro; Naya, Daniel E.

    2014-01-01

    Few studies have evaluated phenotypic plasticity at the community level, considering, for example, plastic responses in an entire species assemblage. In addition, none of these studies have addressed the relationship between phenotypic plasticity and community structure. Within this context, here we assessed the magnitude of seasonal changes in digestive traits (seasonal flexibility), and of changes during short-term fasting (flexibility during fasting), occurring in an entire fish assemblage, comprising ten species, four trophic levels, and a 37-fold range in body mass. In addition, we analyzed the relationship between estimates of digestive flexibility and three basic assemblage structure attributes, i.e., species trophic position, body size, and relative abundance. We found that: (1) Seasonal digestive flexibility was not related with species trophic position or with body size; (2) Digestive flexibility during fasting tended to be inversely correlated with body size, as expected from scaling relationships; (3) Digestive flexibility, both seasonal and during fasting, was positively correlated with species relative abundance. In conclusion, the present study identified two trends in digestive flexibility in relation to assemblage structure, which represents an encouraging departure point in the search of general patterns in phenotypic plasticity at the local community scale. PMID:24651865

  10. Variation in local abundance and species richness of stream fishes in relation to dispersal barriers: Implications for management and conservation

    USGS Publications Warehouse

    Nislow, K.H.; Hudy, M.; Letcher, B.H.; Smith, E.P.

    2011-01-01

    1.Barriers to immigration, all else being equal, should in principle depress local abundance and reduce local species richness. These issues are particularly relevant to stream-dwelling species when improperly designed road crossings act as barriers to migration with potential impacts on the viability of upstream populations. However, because abundance and richness are highly spatially and temporally heterogeneous and the relative importance of immigration on demography is uncertain, population- and community-level effects can be difficult to detect. 2.In this study, we tested the effects of potential barriers to upstream movements on the local abundance and species richness of a diverse assemblage of resident stream fishes in the Monongahela National Forest, West Virginia, U.S.A. Fishes were sampled using simple standard techniques above- and below road crossings that were either likely or unlikely to be barriers to upstream fish movements (based on physical dimensions of the crossing). We predicted that abundance of resident fishes would be lower in the upstream sections of streams with predicted impassable barriers, that the strength of the effect would vary among species and that variable effects on abundance would translate into lower species richness. 3.Supporting these predictions, the statistical model that best accounted for variation in abundance and species richness included a significant interaction between location (upstream or downstream of crossing) and type (passable or impassable crossing). Stream sections located above predicated impassable culverts had fewer than half the number of species and less than half the total fish abundance, while stream sections above and below passable culverts had essentially equivalent richness and abundance. 4.Our results are consistent with the importance of immigration and population connectivity to local abundance and species richness of stream fishes. In turn, these results suggest that when measured at

  11. Are parasite richness and abundance linked to prey species richness and individual feeding preferences in fish hosts?

    PubMed

    Cirtwill, Alyssa R; Stouffer, Daniel B; Poulin, Robert; Lagrue, Clément

    2016-01-01

    Variations in levels of parasitism among individuals in a population of hosts underpin the importance of parasites as an evolutionary or ecological force. Factors influencing parasite richness (number of parasite species) and load (abundance and biomass) at the individual host level ultimately form the basis of parasite infection patterns. In fish, diet range (number of prey taxa consumed) and prey selectivity (proportion of a particular prey taxon in the diet) have been shown to influence parasite infection levels. However, fish diet is most often characterized at the species or fish population level, thus ignoring variation among conspecific individuals and its potential effects on infection patterns among individuals. Here, we examined parasite infections and stomach contents of New Zealand freshwater fish at the individual level. We tested for potential links between the richness, abundance and biomass of helminth parasites and the diet range and prey selectivity of individual fish hosts. There was no obvious link between individual fish host diet and helminth infection levels. Our results were consistent across multiple fish host and parasite species and contrast with those of earlier studies in which fish diet and parasite infection were linked, hinting at a true disconnect between host diet and measures of parasite infections in our study systems. This absence of relationship between host diet and infection levels may be due to the relatively low richness of freshwater helminth parasites in New Zealand and high host-parasite specificity. PMID:26573385

  12. Physical factors affecting the abundance and species richness of fishes in the shallow waters of the southern Bothnian Sea (Sweden)

    NASA Astrophysics Data System (ADS)

    Thorman, Staffan

    1986-03-01

    The relationship between the composition of the fish assemblages and the abiotic environment in seven shallow areas within the same geographical range in the southern Bothnian Sea were studied in May, July, September and November 1982. Eighteen species were found in the areas and the major species were Pungitius pungitius (L.), Pomatoschistus minutus (Pallas), Gasterosteus aculeatus (L.), Phoxinus phoxinus (L.), Pomatoschistus microps (Krøyer) and Gobius niger L. The main purpose of the study was to examine the possible effects of exposure, organic contents in sediments and habitat heterogeneity on species richness and abundance of the assemblages. There was a negative correlation between the organic contents of the sediment and exposure. There were no significant correlations between exposure, organic contents, size of the areas and species numbers but habitat heterogeneity was positively correlated with species number. There were no correlations between fish abundance and heterogeneity of the areas. Negative correlations occurred between the exposure of the areas and fish abundance. The amounts of the pooled benthic fauna were negatively correlated to the exposure. The species/area hypothesis finds no support in the results, because there was no correlation between habitat heterogeneity of an area and its size. The effective fetch combined with the heterogeneity measurement of the areas seemed to be useful indicators of the species composition and fish abundance. Habitat heterogeneity and exposure were the most important structuring factors of these shallow water fish assemblages during the ice-free period and within the local geographical range. The assemblages consist of a mixture of species with marine or limnic origin and they have probably not evolved in the Bothnian Sea or together. They are most likely regulated by their physiological plasticity and not by interactions with other species.

  13. Occurrence and abundance of anisakid nematode larvae in five species of fish from southern Australian waters.

    PubMed

    Shamsi, Shokoofeh; Eisenbarth, Albert; Saptarshi, Shruti; Beveridge, Ian; Gasser, Robin B; Lopata, Andreas L

    2011-04-01

    The aim of the present study was to conduct, in southern Australian waters, a preliminary epidemiological survey of five commercially significant species of fish (yellow-eye mullet, tiger flathead, sand flathead, pilchard and king fish) for infections with anisakid nematodes larvae using a combined morphological-molecular approach. With the exception of king fish, which was farmed and fed commercial pellets, all other species were infected with at least one species of anisakid nematode, with each individual tiger flathead examined being infected. Five morphotypes, including Anisakis, Contracaecum type I and II and Hysterothylacium type IV and VIII, were defined genetically using mutation scanning and targeted sequencing of the second internal transcribed spacer of nuclear ribosomal DNA. The findings of the present study provide a basis for future investigations of the genetic composition of anisakid populations in a wide range of fish hosts in Australia and for assessing their public health significance. PMID:21057811

  14. Assessment of fish abundance and species composition at selected sites in South Dakota: an overview

    USGS Publications Warehouse

    Harwood, Alison

    2010-01-01

    The U.S. Geological Survey (USGS) conducted surveys of streams throughout the State of South Dakota during 2008-09 as part of the U.S. Environmental Protection Agency?s (USEPA) National Rivers and Streams Assessment (NRSA) Program. During 2008-09, as part of the stream assessment, the USGS completed surveys of fish populations and species composition at 64 sites. Fish were inventoried at 60 of the 64 sites, but not at four of the sites because water was too low to sustain fish or specific conductivity was too high to electroshock effectively. Four of the sites were surveyed in 2000-04 during the USEPA's Environmental Monitoring and Assessment Program-West (EMAP-West) project. Two wadeable sites and two boatable sites were revisited for quality-assurance/quality-control requirements. During the study, both wadeable and boatable streams were sampled using electrofishing equipment and methods. Of the 64 sites, 62 were wadeable and 2 were boatable. Procedures for sampling wadeable streams differed slightly from procedures for boatable streams. Backpack electrofishing equipment was used for wadeable streams, whereas boat electrofishing equipment was used for boatable streams. Wadeable streams also were fished in an opposite direction than boatable streams. Several species of fish were collected during the NRSA. Species diversity ranged from 0-11 species in wadeable streams and from 6-26 species in boatable streams. Many common species were sampled during the study. The most frequently sampled fish was the sand shiner (Notropis stramineus), with 609 individuals sampled. In contrast, only one heritage species, the skipjack herring (Alosa chrysochloris), was identified during 2008-09. Common anomalies found in fish caught were parasitic lesions, "black spot disease," and tumors. When comparing the fish sampling results for the four sites visited in both 2000-04 and in 2008-09, more individuals and species were collected during 2008-09 than in 2000-04 at two sites, whereas

  15. Estimating number of species and relative abundances in stream-fish communities: effects of sampling effort and discontinuous spatial distributions

    USGS Publications Warehouse

    Angermeier, Paul L.; Smogor, Roy A.

    1995-01-01

    We sampled fishes and measured microhabitat in series of contiguous habitat units (riffles, runs, pools) in three Virginia streams. We used Monte Carlo simulations to construct hypothetical series of habitat units, then examined how number of species, similarity in relative abundances, and number of microhabitats accumulated with increasing number of habitat units (i.e., sampling effort). Proportions of all species and microhabitats represented were relatively low and variable at low sampling effort, but increased asymptotically and became less variable with greater sampling effort. To facilitate comparisons among streams, we fitted simulation results to negative exponential curves. The curves indicated that 90% of the species present were usually found by sampling 5 to 14 habitat units (stream length of 22–67 stream widths). Estimates of species relative abundances required less sampling effort for a given accuracy than estimates of number of species. Rates of species accumulation (with effort) varied among streams and reflected discontinuity in species distributions among habitat units. Most discontinuity seemed to be due to low population density rather than to habitat selectivity. Results from an Illinois stream corroborated our findings from Virginia, and suggested that greater sampling effort is needed to characterize fish community structure in more homogeneous stream reaches.

  16. Refuge habitats for fishes during seasonal drying in an intermittent stream: Movement, survival and abundance of three minnow species

    USGS Publications Warehouse

    Hodges, S.W.; Magoulick, D.D.

    2011-01-01

    Drought and summer drying can be important disturbance events in many small streams leading to intermittent or isolated habitats. We examined what habitats act as refuges for fishes during summer drying, hypothesizing that pools would act as refuge habitats. We predicted that during drying fish would show directional movement into pools from riffle habitats, survival rates would be greater in pools than in riffles, and fish abundance would increase in pool habitats. We examined movement, survival and abundance of three minnow species, bigeye shiner (Notropis boops), highland stoneroller (Campostoma spadiceum) and creek chub (Semotilus atromaculatus), during seasonal stream drying in an Ozark stream using a closed robust multi-strata mark-recapture sampling. Population parameters were estimated using plausible models within program MARK, where a priori models are ranked using Akaike's Information Criterion. Creek chub showed directional movement into pools and increased survival and abundance in pools during drying. Highland stonerollers showed strong directional movement into pools and abundance increased in pools during drying, but survival rates were not significantly greater in pools than riffles. Bigeye shiners showed high movement rates during drying, but the movement was non-directional, and survival rates were greater in riffles than pools. Therefore, creek chub supported our hypothesis and pools appear to act as refuge habitats for this species, whereas highland stonerollers partly supported the hypothesis and bigeye shiners did not support the pool refuge hypothesis. Refuge habitats during drying are species dependent. An urgent need exists to further understand refuge habitats in streams given projected changes in climate and continued alteration of hydrological regimes. ?? 2011 Springer Basel AG (outside the USA).

  17. Refuge habitats for fishes during seasonal drying in an intermittent stream: movement, survival and abundance of three minnow species

    USGS Publications Warehouse

    Hodges, S.W.; Magoulick, Daniel D.

    2011-01-01

    Drought and summer drying can be important disturbance events in many small streams leading to intermittent or isolated habitats. We examined what habitats act as refuges for fishes during summer drying, hypothesizing that pools would act as refuge habitats. We predicted that during drying fish would show directional movement into pools from riffle habitats, survival rates would be greater in pools than in riffles, and fish abundance would increase in pool habitats. We examined movement, survival and abundance of three minnow species, bigeye shiner (Notropis boops), highland stoneroller (Campostoma spadiceum) and creek chub (Semotilus atromaculatus), during seasonal stream drying in an Ozark stream using a closed robust multi-strata mark-recapture sampling. Population parameters were estimated using plausible models within program MARK, where a priori models are ranked using Akaike's Information Criterion. Creek chub showed directional movement into pools and increased survival and abundance in pools during drying. Highland stonerollers showed strong directional movement into pools and abundance increased in pools during drying, but survival rates were not significantly greater in pools than riffles. Bigeye shiners showed high movement rates during drying, but the movement was non-directional, and survival rates were greater in riffles than pools. Therefore, creek chub supported our hypothesis and pools appear to act as refuge habitats for this species, whereas highland stonerollers partly supported the hypothesis and bigeye shiners did not support the pool refuge hypothesis. Refuge habitats during drying are species dependent. An urgent need exists to further understand refuge habitats in streams given projected changes in climate and continued alteration of hydrological regimes.

  18. Seasonal variation in species composition and abundance of demersal fish and invertebrates in a Seagrass Natural Reserve on the eastern coast of the Shandong Peninsula, China

    NASA Astrophysics Data System (ADS)

    Xu, Qiang; Guo, Dong; Zhang, Peidong; Zhang, Xiumei; Li, Wentao; Wu, Zhongxin

    2016-03-01

    Seagrass habitats are structurally complex ecosystems, which support high productivity and biodiversity. In temperate systems the density of seagrass may change seasonally, and this may influence the associated fish and invertebrate community. Little is known about the role of seagrass beds as possible nursery areas for fish and invertebrates in China. To study the functioning of a seagrass habitat in northern China, demersal fish and invertebrates were collected monthly using traps, from February 2009 to January 2010. The density, leaf length and biomass of the dominant seagrass Zostera marina and water temperature were also measured. The study was conducted in a Seagrass Natural Reserve (SNR) on the eastern coast of the Shandong Peninsula, China. A total of 22 fish species and five invertebrate species were recorded over the year. The dominant fish species were Synechogobius ommaturus, Sebastes schlegelii, Pholis fangi, Pagrus major and Hexagrammos otakii and these species accounted for 87% of the total number of fish. The dominant invertebrate species were Charybdis japonica and Octopus variabilis and these accounted for 98% of the total abundance of invertebrates. There was high temporal variation in species composition and abundance. The peak number of fish species occurred in August-October 2009, while the number of individual fish and biomass was highest during November 2009. Invertebrate numbers and biomass was highest in March, April, July and September 2009. Temporal changes in species abundance of fishes and invertebrates corresponded with changes in the shoot density and leaf length of the seagrass, Zostera marina.

  19. Using underwater cameras to assess the effects of snorkeler and SCUBA diver presence on coral reef fish abundance, family richness, and species composition.

    PubMed

    Dearden, P; Theberge, M; Yasué, M

    2010-04-01

    The results of underwater visual fish censuses (UVC) could be affected by fish changing their behavior in response to the snorkeler or diver conducting the survey. We used an underwater video camera to assess how fish abundance, family richness, and community composition were affected by the presence of snorkelers (n = 12) and self-contained underwater breathing apparatus (SCUBA) divers (n = 6) on a coral reef in Thailand. The total number of families, abundance of some fish families, and overall species composition showed significant differences before and during snorkeling disturbances. We did not detect significant and consistent changes to these parameters in the presence of a SCUBA diver; however, this could be a result of lower statistical power. We suggest that the use of a stationary video camera may help cross-check data that is collected through UVC to assess the true family composition and document the presence of rare and easily disturbed species. PMID:19353295

  20. Climate and local abundance in freshwater fishes

    PubMed Central

    Knouft, Jason H.; Anthony, Melissa M.

    2016-01-01

    Identifying factors regulating variation in numbers of individuals among populations across a species' distribution is a fundamental goal in ecology. A common prediction, often referred to as the abundant-centre hypothesis, suggests that abundance is highest near the centre of a species' range. However, because of the primary focus on the geographical position of a population, this framework provides little insight into the environmental factors regulating local abundance. While range-wide variation in population abundance associated with environmental conditions has been investigated in terrestrial species, the relationship between climate and local abundance in freshwater taxa across species' distributions is not well understood. We used GIS-based temperature and precipitation data to determine the relationships between climatic conditions and range-wide variation in local abundance for 19 species of North American freshwater fishes. Climate predicted a portion of the variation in local abundance among populations for 18 species. In addition, the relationship between climatic conditions and local abundance varied among species, which is expected as lineages partition the environment across geographical space. The influence of local habitat quality on species persistence is well documented; however, our results also indicate the importance of climate in regulating population sizes across a species geographical range, even in aquatic taxa. PMID:27429769

  1. Climate and local abundance in freshwater fishes.

    PubMed

    Knouft, Jason H; Anthony, Melissa M

    2016-06-01

    Identifying factors regulating variation in numbers of individuals among populations across a species' distribution is a fundamental goal in ecology. A common prediction, often referred to as the abundant-centre hypothesis, suggests that abundance is highest near the centre of a species' range. However, because of the primary focus on the geographical position of a population, this framework provides little insight into the environmental factors regulating local abundance. While range-wide variation in population abundance associated with environmental conditions has been investigated in terrestrial species, the relationship between climate and local abundance in freshwater taxa across species' distributions is not well understood. We used GIS-based temperature and precipitation data to determine the relationships between climatic conditions and range-wide variation in local abundance for 19 species of North American freshwater fishes. Climate predicted a portion of the variation in local abundance among populations for 18 species. In addition, the relationship between climatic conditions and local abundance varied among species, which is expected as lineages partition the environment across geographical space. The influence of local habitat quality on species persistence is well documented; however, our results also indicate the importance of climate in regulating population sizes across a species geographical range, even in aquatic taxa. PMID:27429769

  2. Composition and Relative Abundance of Fish Species in the Lower White Salmon River, Washington, Prior to the Removal of Condit Dam

    USGS Publications Warehouse

    Allen, M. Brady; Connolly, Patrick J.

    2011-01-01

    Information about the composition and relative abundance of fish species was collected by a rotary screw trap and backpack electrofishing in the lower White Salmon River, Washington. The information was collected downstream of Condit Dam, which is at river kilometer (rkm) 5.2, and is proposed for removal in October 2011. A rotary screw trap was installed in the White Salmon River at rkm 1.5 and operated from March through June during 2006-09. All captured fish were identified to species and enumerated. Daily subsets of fish were weighed, measured, and fin clipped for a genetic analysis by the U.S. Fish and Wildlife Service. *Fall Chinook salmon (Oncorhynchus tshawytscha) were captured in the highest numbers (n=18, 640), and were composed of two stocks: tule and upriver bright. Almost all captured fall Chinook salmon were age-0, with only 16 (0.09 percent) being age-1 or older. *Tule fall Chinook salmon, the native stock, generally out-migrated from mid-March through early April. The tule stock was the more abundant fall Chinook salmon subspecies, comprising 85 percent of those captured in the trap. *Upriver bright fall Chinook salmon comprised 15 percent of the Chinook salmon catch and generally out-migrated from late May to early June. *Coho salmon (O. kisutch) and steelhead trout (O. mykiss) were captured by the rotary screw trap in all years. Coho salmon were caught in low numbers (n=661) and 69 percent were age-0 fish. Steelhead were slightly more abundant (n=679) than coho salmon and 84 percent were age-1 or older fish. Trap efficiency estimates varied widely (range, 0-10 percent) by species, fish size, and time of year. However, if we use only the estimates from efficiency tests where more than 300 wild age-0 Chinook salmon were released, there was a mean trapping efficiency of 1.4 percent (n=4, median, 1.3 percent, range, 0.3-2.4 percent) during the tule out-migration period, and a mean trapping efficiency of 0.8 percent (n=2, range, 0.3-1.2 percent) during

  3. Can parasites be indicators of free-living diversity? Relationships between species richness and the abundance of larval trematodes and of local benthos and fishes

    USGS Publications Warehouse

    Hechinger, R.F.; Lafferty, K.D.; Huspeni, T.C.; Brooks, A.J.; Kuris, A.M.

    2007-01-01

    Measuring biodiversity is difficult. This has led to efforts to seek taxa whose species richness correlates with the species richness of other taxa. Such indicator taxa could then reduce the time and cost of assessing the biodiversity of the more extensive community. The search for species richness correlations has yielded mixed results, however. This may be primarily because of the lack of functional relationships between the taxa studied. Trematode parasites are highly promising bioindicators. Diverse assemblages of larval trematode parasites are easily sampled in intermediate host snails. Through their life cycles these parasites are functionally coupled with the surrounding free-living diversity of vertebrate and invertebrate animals. It has been shown that larval trematodes in snails correlate positively with bird diversity and abundance. Here, we explore whether trematodes also correlate with standard measures of fishes, and large and small benthos, for 32 sites in three wetlands. We found associations between trematodes and benthic communities that were not consistent across wetlands. The associations were, however, consistently positive for large benthic species richness and density. Some of the contrasting associations between trematode and benthos may be explained by negative associations between large and small benthos. We found no associations with fish communities (probably because of the inadequacy of standard "snapshot" sampling methods for highly mobile fishes). The results support further exploration of trematodes as bioindicators of diversity and abundance of animal communities. ?? 2006 Springer-Verlag.

  4. Hydroacoustic estimates of fish abundance

    SciTech Connect

    Wilson, W.K.

    1991-03-01

    Hydroacoustics, as defined in the context of this report, is the use of a scientific sonar system to determine fish densities with respect to numbers and biomass. These two parameters provide a method of monitoring reservoir fish populations and detecting gross changes in the ecosystem. With respect to southeastern reservoirs, hydroacoustic surveys represent a new method of sampling open water areas and the best technology available. The advantages of this technology are large amounts of data can be collected in a relatively short period of time allowing improved statistical interpretation and data comparison, the pelagic (open water) zone can be sampled efficiently regardless of depth, and sampling is nondestructive and noninvasive with neither injury to the fish nor alteration of the environment. Hydroacoustics cannot provide species identification and related information on species composition or length/weight relationships. Also, sampling is limited to a minimum depth of ten feet which precludes the use of this equipment for sampling shallow shoreline areas. The objective of this study is to use hydroacoustic techniques to estimate fish standing stocks (i.e., numbers and biomass) in several areas of selected Tennessee Valley Reservoirs as part of a base level monitoring program to assess long-term changes in reservoir water quality.

  5. [Trophic interactions of the six most abundant fish species in the artisanal fishery in two bays, central Mexican Pacific].

    PubMed

    Flores Ortega, J R; Godínez Domínguez, E; Rojo Vázquez, J A; Corgos, A; Galván Piña, V H; Sansón González, G

    2010-03-01

    We surveyed the trophic components in six species of Bahía de Navidad and Bahía de Chamela: Microlepidotus brevipinnis, Caranx caballus, Haemulon flaviguttatum, Lutjanus guttatus, L. argentiventris and Mulloidichthys dentatus. Two main seasonal periods were considered: 1) North Equatorial Counter Current NECC period influence (T1) and 2) California Current CC period influence (T2). In Bahía de Navidad 78 prey taxa were identified in the stomachs. From July to December (T1), 64 prey taxa were found, and from January to June (T2), 45 prey items. In Bahía de Chamela 93 prey items were identified; 74 during T1 and 60 during T2. The highest prey number was found in the stomachs of M. dentatus during T1 in Bahía de Navidad and the lowest prey number (7) was recorded in H. flaviguttatum in Bahía de Navidad in the same period. Crustaceans were the most frequently recorded prey items, followed by fishes, mollusks, polychaetes, and echinoderms in both seasonal periods and sites. The six fish species studied are considered as specialist feeders due the low values of the niche breadth index. There was little similarity among the diets. PMID:20411730

  6. Mangroves Enhance Reef Fish Abundance at the Caribbean Regional Scale

    PubMed Central

    Serafy, Joseph E.; Shideler, Geoffrey S.; Araújo, Rafael J.; Nagelkerken, Ivan

    2015-01-01

    Several studies conducted at the scale of islands, or small sections of continental coastlines, have suggested that mangrove habitats serve to enhance fish abundances on coral reefs, mainly by providing nursery grounds for several ontogenetically-migrating species. However, evidence of such enhancement at a regional scale has not been reported, and recently, some researchers have questioned the mangrove-reef subsidy effect. In the present study, using two different regression approaches, we pursued two questions related to mangrove-reef connectivity at the Caribbean regional scale: (1) Are reef fish abundances limited by mangrove forest area?; and (2) Are mean reef fish abundances proportional to mangrove forest area after taking human population density and latitude into account? Specifically, we tested for Caribbean-wide mangrove forest area effects on the abundances of 12 reef fishes that have been previously characterized as “mangrove-dependent”. Analyzed were data from an ongoing, long-term (20-year) citizen-scientist fish monitoring program; coastal human population censuses; and several wetland forest information sources. Quantile regression results supported the notion that mangrove forest area limits the abundance of eight of the 12 fishes examined. Linear mixed-effects regression results, which considered potential human (fishing and habitat degradation) and latitudinal influences, suggested that average reef fish densities of at least six of the 12 focal fishes were directly proportional to mangrove forest area. Recent work questioning the mangrove-reef fish subsidy effect likely reflects a failure to: (1) focus analyses on species that use mangroves as nurseries, (2) consider more than the mean fish abundance response to mangrove forest extent; and/or (3) quantitatively account for potentially confounding human impacts, such as fishing pressure and habitat degradation. Our study is the first to demonstrate at a large regional scale (i.e., the Wider

  7. Mangroves Enhance Reef Fish Abundance at the Caribbean Regional Scale.

    PubMed

    Serafy, Joseph E; Shideler, Geoffrey S; Araújo, Rafael J; Nagelkerken, Ivan

    2015-01-01

    Several studies conducted at the scale of islands, or small sections of continental coastlines, have suggested that mangrove habitats serve to enhance fish abundances on coral reefs, mainly by providing nursery grounds for several ontogenetically-migrating species. However, evidence of such enhancement at a regional scale has not been reported, and recently, some researchers have questioned the mangrove-reef subsidy effect. In the present study, using two different regression approaches, we pursued two questions related to mangrove-reef connectivity at the Caribbean regional scale: (1) Are reef fish abundances limited by mangrove forest area?; and (2) Are mean reef fish abundances proportional to mangrove forest area after taking human population density and latitude into account? Specifically, we tested for Caribbean-wide mangrove forest area effects on the abundances of 12 reef fishes that have been previously characterized as "mangrove-dependent". Analyzed were data from an ongoing, long-term (20-year) citizen-scientist fish monitoring program; coastal human population censuses; and several wetland forest information sources. Quantile regression results supported the notion that mangrove forest area limits the abundance of eight of the 12 fishes examined. Linear mixed-effects regression results, which considered potential human (fishing and habitat degradation) and latitudinal influences, suggested that average reef fish densities of at least six of the 12 focal fishes were directly proportional to mangrove forest area. Recent work questioning the mangrove-reef fish subsidy effect likely reflects a failure to: (1) focus analyses on species that use mangroves as nurseries, (2) consider more than the mean fish abundance response to mangrove forest extent; and/or (3) quantitatively account for potentially confounding human impacts, such as fishing pressure and habitat degradation. Our study is the first to demonstrate at a large regional scale (i.e., the Wider

  8. An abundant small sized fish as keystone species? The effect of Pomatoschistus microps on food webs and its trophic role in two intertidal benthic communities: A modeling approach

    NASA Astrophysics Data System (ADS)

    Pockberger, Moritz; Kellnreitner, Florian; Ahnelt, Harald; Asmus, Ragnhild; Asmus, Harald

    2014-02-01

    Ecological network analysis (ENA) was used to study the effects of Pomatoschistus microps on energy transport through the food web, its impact on other compartments and its possible role as a keystone species in the trophic webs of an Arenicola tidal flat ecosystem and a sparse Zostera noltii bed ecosystem. Three ENA models were constructed: (a) model 1 contains data of the original food web from prior research in the investigated area by Baird et al. (2007), (b) an updated model 2 which included biomass and diet data of P. microps from recent sampling, and (c) model 3 simulating a food web without P. microps. A comparison of energy transport between the different models revealed that more energy is transported from lower trophic levels up the food chain, in the presence of P. microps (models 1 and 2) than in its absence (model 3). Calculations of the keystone index (KSi) revealed the high overall impact (measured as εi) of this fish species on food webs. In model 1, P. microps was assigned a low KSi in the Arenicola flat and in the sparse Z. noltii bed. Calculations in model 2 ranked P. microps first for keystoneness and εi in both communities, the Arenicola flat and the sparse Z. noltii bed. Taken together, our results give insight into the role of P. microps when considering a whole food web and reveal direct and indirect trophic interactions of this small-sized fish species. These results might illustrate the impact and importance of abundant, widespread species in food webs and facilitate further investigations.

  9. Hydroacoustic estimates of fish abundance

    SciTech Connect

    Wilson, W.K.

    1992-06-01

    Mobile hydroacoustic surveys are a recent addition to the sampling techniques available to fisheries biologists. Hydroacoustic techniques for fish stock assessment and monitoring are efficient in providingquantitative biomass estimates, absolute population estimates, fish distribution patterns, and size structure statistics. Other advantages of hydroacoustic surveys include a better method of sampling reservoir pelagic (open water) zones than is available with other techniques, collection of large amounts of data in a relatively short time allowing improved statistical interpretation and data comparisons, and non-destructive, non-invasive sampling that neither destroys the sampled fish nor disturbs the environment. The objective of this study is to use hydroacoustic techniques to estimate fish standing stocks (i.e., numbersand biomass) in several areas of selected Tennessee Valley Reservoirs as part of a base level monitoring program to assess long-term changes in reservoir water quality.

  10. How selection structures species abundance distributions

    PubMed Central

    Magurran, Anne E.; Henderson, Peter A.

    2012-01-01

    How do species divide resources to produce the characteristic species abundance distributions seen in nature? One way to resolve this problem is to examine how the biomass (or capacity) of the spatial guilds that combine to produce an abundance distribution is allocated among species. Here we argue that selection on body size varies across guilds occupying spatially distinct habitats. Using an exceptionally well-characterized estuarine fish community, we show that biomass is concentrated in large bodied species in guilds where habitat structure provides protection from predators, but not in those guilds associated with open habitats and where safety in numbers is a mechanism for reducing predation risk. We further demonstrate that while there is temporal turnover in the abundances and identities of species that comprise these guilds, guild rank order is conserved across our 30-year time series. These results demonstrate that ecological communities are not randomly assembled but can be decomposed into guilds where capacity is predictably allocated among species. PMID:22787020

  11. Invasive lionfish reduce native fish abundance on a regional scale.

    PubMed

    Ballew, Nicholas G; Bacheler, Nathan M; Kellison, G Todd; Schueller, Amy M

    2016-01-01

    Invasive lionfish pose an unprecedented threat to biodiversity and fisheries throughout Atlantic waters off of the southeastern United States, the Caribbean, and the Gulf of Mexico. Here, we employ a spatially replicated Before-After-Control-Impact analysis with temporal pairing to quantify for the first time the impact of the lionfish invasion on native fish abundance across a broad regional scale and over the entire duration of the lionfish invasion (1990-2014). Our results suggest that 1) lionfish-impacted areas off of the southeastern United States are most prevalent off-shore near the continental shelf-break but are also common near-shore and 2) in impacted areas, lionfish have reduced tomtate (a native forage fish) abundance by 45% since the invasion began. Tomtate served as a model native fish species in our analysis, and as such, it is likely that the lionfish invasion has had similar impacts on other species, some of which may be of economic importance. Barring the development of a control strategy that reverses the lionfish invasion, the abundance of lionfish in the Atlantic, Caribbean, and Gulf of Mexico will likely remain at or above current levels. Consequently, the effect of lionfish on native fish abundance will likely continue for the foreseeable future. PMID:27578096

  12. Invasive lionfish reduce native fish abundance on a regional scale

    PubMed Central

    Ballew, Nicholas G.; Bacheler, Nathan M.; Kellison, G. Todd; Schueller, Amy M.

    2016-01-01

    Invasive lionfish pose an unprecedented threat to biodiversity and fisheries throughout Atlantic waters off of the southeastern United States, the Caribbean, and the Gulf of Mexico. Here, we employ a spatially replicated Before-After-Control-Impact analysis with temporal pairing to quantify for the first time the impact of the lionfish invasion on native fish abundance across a broad regional scale and over the entire duration of the lionfish invasion (1990–2014). Our results suggest that 1) lionfish-impacted areas off of the southeastern United States are most prevalent off-shore near the continental shelf-break but are also common near-shore and 2) in impacted areas, lionfish have reduced tomtate (a native forage fish) abundance by 45% since the invasion began. Tomtate served as a model native fish species in our analysis, and as such, it is likely that the lionfish invasion has had similar impacts on other species, some of which may be of economic importance. Barring the development of a control strategy that reverses the lionfish invasion, the abundance of lionfish in the Atlantic, Caribbean, and Gulf of Mexico will likely remain at or above current levels. Consequently, the effect of lionfish on native fish abundance will likely continue for the foreseeable future. PMID:27578096

  13. Diversity is maintained by seasonal variation in species abundance

    PubMed Central

    2013-01-01

    Background Some of the most marked temporal fluctuations in species abundances are linked to seasons. In theory, multispecies assemblages can persist if species use shared resources at different times, thereby minimizing interspecific competition. However, there is scant empirical evidence supporting these predictions and, to the best of our knowledge, seasonal variation has never been explored in the context of fluctuation-mediated coexistence. Results Using an exceptionally well-documented estuarine fish assemblage, sampled monthly for over 30 years, we show that temporal shifts in species abundances underpin species coexistence. Species fall into distinct seasonal groups, within which spatial resource use is more heterogeneous than would be expected by chance at those times when competition for food is most intense. We also detect seasonal variation in the richness and evenness of the community, again linked to shifts in resource availability. Conclusions These results reveal that spatiotemporal shifts in community composition minimize competitive interactions and help stabilize total abundance. PMID:24007204

  14. Effects of flooding on abundance of native and nonnative fishes downstream from a small impoundment

    USGS Publications Warehouse

    Schultz, A.A.; Maughan, O.E.; Bonar, Scott A.; Matter, W.J.

    2003-01-01

    Flooding can benefit native fishes in southwestern streams by disproportionately displacing nonnative fishes. We examined how the presence of an upstream impoundment affected this relationship in lower Sonoita Creek, Arizona. Nonnative species not found in the reservoir decreased in abundance in lower Sonoita Creek after flooding. The catch and relative abundance of some nonnative species found in both the reservoir and the creek increased in lower Sonoita Creek after flooding. Movement of nonnative fishes out of the reservoir via the spillway during periods of high water probably contributes to the persistence and abundance of these species downstream. Both preventing nonnative fishes from escaping reservoirs and the release of flushing flows would aid conservation of native southwestern fishes downstream.

  15. Clonal growth and plant species abundance

    PubMed Central

    Herben, Tomáš; Nováková, Zuzana; Klimešová, Jitka

    2014-01-01

    Background and Aims Both regional and local plant abundances are driven by species' dispersal capacities and their abilities to exploit new habitats and persist there. These processes are affected by clonal growth, which is difficult to evaluate and compare across large numbers of species. This study assessed the influence of clonal reproduction on local and regional abundances of a large set of species and compared the predictive power of morphologically defined traits of clonal growth with data on actual clonal growth from a botanical garden. The role of clonal growth was compared with the effects of seed reproduction, habitat requirements and growth, proxied both by LHS (leaf–height–seed) traits and by actual performance in the botanical garden. Methods Morphological parameters of clonal growth, actual clonal reproduction in the garden and LHS traits (leaf-specific area – height – seed mass) were used as predictors of species abundance, both regional (number of species records in the Czech Republic) and local (mean species cover in vegetation records) for 836 perennial herbaceous species. Species differences in habitat requirements were accounted for by classifying the dataset by habitat type and also by using Ellenberg indicator values as covariates. Key Results After habitat differences were accounted for, clonal growth parameters explained an important part of variation in species abundance, both at regional and at local levels. At both levels, both greater vegetative growth in cultivation and greater lateral expansion trait values were correlated with higher abundance. Seed reproduction had weaker effects, being positive at the regional level and negative at the local level. Conclusions Morphologically defined traits are predictive of species abundance, and it is concluded that simultaneous investigation of several such traits can help develop hypotheses on specific processes (e.g. avoidance of self-competition, support of offspring) potentially

  16. Influence of wood and forests on fish abundance and richness in a large floodplain river

    NASA Astrophysics Data System (ADS)

    Gregory, S.; Wildman, R. C.

    2005-05-01

    We investigated the influence of large wood and adjacent floodplain forests on fish assemblages along the 230-km mainstem of the Willamette River, Oregon. Fish were sampled in open reaches using boat electroshocking, beach seining, and backpack electroshocking in paired sites with intact forest and land converted to agriculture or urban use. Fish abundance and richness were statistically significantly greater in reaches with intact forest. We observed that wood abundance in the river was related to density of trees along the floodplain margin and developed an intensive sampling approach for determining fish abundance and richness in accumulations of large wood in the river. Fish were sampled from "wood corrals" and marked by fin clipping. These sites were sampled the following day to determine the abundances of each species by mark-recapture. Nets were placed around similar areas in adjacent habitats without wood. Fish numbers around wood accumulations were more than double those in areas without wood. The number of fish species was greater by an average of four species in sites with wood. These results were used to project the consequence of historical changes in fish abundance and richness in the Willamette River and forecast possible responses to future land use change.

  17. Factors affecting the abundance of selected fishes near oil and gas platforms in the northern Gulf of Mexico

    SciTech Connect

    Stanley, D.R.; Wilson, C.A. )

    1991-01-01

    A logbook program was initiated to determine the relative abundance of selected fish species around oil and gas platforms off the Louisiana coast. Logbooks were maintained by 55 anglers and 10 charterboat operators from March 1987 to March 1988. A total of 36,839 fish were caught representing over 46 different species. Principal component analysis (PCA) grouped the seventeen most abundant species into reef fish, pelagic fish, bluefish-red drum, Atlantic croaker-silver/sand seatrout, and cobia-shark-blue runner associations. Multiple regression analyses were used to compare PCA groupings to physical platform, temporal, geological, and angler characteristic variables and their interactions. Reef fish, Atlantic croaker, and silver/sand seatrout abundances were highest near large, structurally complex platforms in relatively deep water. High spotted seatrout abundances were correlated with small, unmanned oil and gas platforms in shallow water. Pelagic fish, bluefish, red drum, cobia, and shark abundances were not related to the physical parameters of the platforms.

  18. Species Abundance Patterns in Complex Evolutionary Dynamics

    NASA Astrophysics Data System (ADS)

    Tokita, Kei

    2004-10-01

    An analytic theory of species abundance patterns (SAPs) in biological networks is presented. The theory is based on multispecies replicator dynamics equivalent to the Lotka-Volterra equation, with diverse interspecies interactions. Various SAPs observed in nature are derived from a single parameter. The abundance distribution is formed like a widely observed left-skewed lognormal distribution. As the model has a general form, the result can be applied to similar patterns in other complex biological networks, e.g., gene expression.

  19. Indirect consequences of fishing: reduction of coralline algae suppresses juvenile coral abundance

    NASA Astrophysics Data System (ADS)

    O'Leary, J. K.; Potts, D. C.; Braga, J. C.; McClanahan, T. R.

    2012-06-01

    Removing predatory fishes has effects that cascade through ecosystems via interactions between species and functional groups. In Kenyan reef lagoons, fishing-induced trophic cascades produce sea urchin-dominated grazing communities that greatly reduce the overall cover of crustose coralline algae (CCA). Certain species of CCA enhance coral recruitment by chemically inducing coral settlement. If sea urchin grazing reduces cover of settlement-inducing CCA, coral recruitment and hence juvenile coral abundance may also decline on fished reefs. To determine whether fishing-induced changes in CCA influence coral recruitment and abundance, we compared (1) CCA taxonomic compositions and (2) taxon-specific associations between CCA and juvenile corals under three fisheries management systems: closed, gear-restricted, and open-access. On fished reefs (gear-restricted and open-access), abundances of two species of settlement-inducing CCA, Hydrolithon reinboldii and H. onkodes, were half those on closed reefs. On both closed and fished reefs, juveniles of four common coral families (Poritidae, Pocilloporidae, Agariciidae, and Faviidae) were more abundant on Hydrolithon than on any other settlement substrate. Coral densities were positively correlated with Hydrolithon spp. cover and were significantly lower on fished than on closed reefs, suggesting that fishing indirectly reduces coral recruitment or juvenile success over large spatial scales via reduction in settlement-inducing CCA. Therefore, managing reefs for higher cover of settlement-inducing CCA may enhance coral recruitment or juvenile survival and help to maintain the ecological and structural stability of reefs.

  20. Abundance exchange models of fish assemblages along the Hudson River Estuary Gradient, New York.

    PubMed

    Singkran, Nuanchan; Bain, Mark B

    2008-01-01

    The spatially explicit abundance exchange model (AEM) was built for four fish species: winter flounder (Pseudopleuronectes americanus), Atlantic silverside (Menidia menidia), eastern silvery minnow (Hybognathus regius), and striped bass (Morone saxatilis) along the Hudson River estuary gradient, New York. The fish and habitat data during 1974-1997 were used to develop and calibrate the AEM; and the fish data during 1998-2001 was used to validate the model. Preference indexes of fish species for dissolved oxygen, salinity, water temperature, and bottom substrates along the gradient were estimated; and these were used to compute habitat preference (HP) of the associated fish species. The species HP was a key variable in the AEM to quantify abundance and distribution patterns of the associated species along the gradient. The AEM could efficiently predict abundance and distribution patterns of all modeled species except striped bass. The model ability for predicting a local distribution range of a fish species with broad tolerance on changing environment like striped bass should be improved. PMID:19092189

  1. SPATIO-TEMPORAL FLUCTUATIONS IN THE DISTRIBUTION AND ABUNDANCE OF DEMERSAL FISH AND EPIBENTHIC CRUSTACEANS IN YAQUINA BAY, OREGON

    EPA Science Inventory

    A total of over 32,000 demersal fish and epibenthic crustaceans belonging to 62 species were caught in 42 biweekly trawls from 10 stations in Yaquina Bay, Oregon, during 1967 and 1968. English sole, Parophrys vetulus, was the most abundant species. eventeen species (13 fishes and...

  2. Community structure influences species' abundance along environmental gradients.

    PubMed

    Eloranta, Antti P; Helland, Ingeborg P; Sandlund, Odd T; Hesthagen, Trygve; Ugedal, Ola; Finstad, Anders G

    2016-01-01

    Species' response to abiotic environmental variation can be influenced by local community structure and interspecific interactions, particularly in restricted habitats such as islands and lakes. In temperate lakes, future increase in water temperature and run-off of terrestrial (allochthonous) dissolved organic carbon (DOC) are predicted to alter community composition and the overall ecosystem productivity. However, little is known about how the present community structure and abiotic environmental variation interact to affect the abundance of native fish populations. We used a space-for-time approach to study how local community structure interact with lake morphometric and climatic characteristics (i.e. temperature and catchment productivity) to affect brown trout (Salmo trutta L.) yield in 283 Norwegian lakes located in different biogeographical regions. Brown trout yield (based on data from standardized survey gill net fishing; g 100 m(-2) gill net night(-1)) was generally lower in lakes where other fish species were present than in lakes with brown trout only. The yield showed an overall negative relationship with increasing temperature and a positive relationship with lake shoreline complexity. Brown trout yield was also negatively correlated with DOC load (measured using Normalized Difference Vegetation Index as a proxy) and lake size and depth (measured using terrain slope as a proxy), but only in lakes where other fish species were present. The observed negative response of brown trout yield to increasing DOC load and proportion of the pelagic open-water area is likely due to restricted (littoral) niche availability and competitive dominance of more pelagic fishes such as Arctic charr (Salvelinus alpinus (L.)). Our study highlights that, through competitive interactions, the local community structure can influence the response of a species' abundance to variation in abiotic conditions. Changes in biomass and niche use of top predators (such as the brown

  3. Estimating abundance in the presence of species uncertainty

    USGS Publications Warehouse

    Chambert, Thierry A; Hossack, Blake R.; Fishback, LeeAnn; Davenport, Jon M.

    2016-01-01

    1.N-mixture models have become a popular method for estimating abundance of free-ranging animals that are not marked or identified individually. These models have been used on count data for single species that can be identified with certainty. However, co-occurring species often look similar during one or more life stages, making it difficult to assign species for all recorded captures. This uncertainty creates problems for estimating species-specific abundance and it can often limit life stages to which we can make inference. 2.We present a new extension of N-mixture models that accounts for species uncertainty. In addition to estimating site-specific abundances and detection probabilities, this model allows estimating probability of correct assignment of species identity. We implement this hierarchical model in a Bayesian framework and provide all code for running the model in BUGS-language programs. 3.We present an application of the model on count data from two sympatric freshwater fishes, the brook stickleback (Culaea inconstans) and the ninespine stickleback (Pungitius pungitius), ad illustrate implementation of covariate effects (habitat characteristics). In addition, we used a simulation study to validate the model and illustrate potential sample size issues. We also compared, for both real and simulated data, estimates provided by our model to those obtained by a simple N-mixture model when captures of unknown species identification were discarded. In the latter case, abundance estimates appeared highly biased and very imprecise, while our new model provided unbiased estimates with higher precision. 4.This extension of the N-mixture model should be useful for a wide variety of studies and taxa, as species uncertainty is a common issue. It should notably help improve investigation of abundance and vital rate characteristics of organisms’ early life stages, which are sometimes more difficult to identify than adults.

  4. Abundance and tidal behaviour of pelagic fish in the gateway to the Wadden Sea

    NASA Astrophysics Data System (ADS)

    Couperus, Bram; Gastauer, Sven; Fässler, Sascha M. M.; Tulp, Ingrid; van der Veer, Henk W.; Poos, Jan Jaap

    2016-03-01

    The shallow coast of The Netherlands is an important habitat for small pelagic fish. They form one of the major links between plankton and the higher trophic levels. Predatory fish, sea mammals and birds rely on small pelagic fish as a major food source. Currently, monitoring of fish in the Dutch coastal zone mainly focuses on demersal species, using bottom trawls and fykes. Four hydro-acoustic surveys were carried out in May and October 2010/2011 in the Marsdiep area, a relatively deep tidal inlet in the western Wadden Sea, to quantify abundances of pelagic fish. The aims of this study were to (1) describe temporal and vertical variations in fish distribution and school dimensions in relation to tide, and (2) estimate biomass of pelagic fish and their proportion to total fish biomass. The biomass of pelagic fish in the Marsdiep area ranged between 23 and 411 kg/ha. These were mainly sprat, but also young herring, anchovy and pilchard. The fish was scattered in small schools with volumes smaller than 5m3 and concentrated in the top 10 m below the surface. There was a clear effect of tidal cycle on school volume and fish abundance, with larger densities and larger schools at high tide compared to low tide. In May, sandeel contributed substantially to the pelagic assemblage, whereas in October sandeel was absent in the trawl catches, most likely because they stayed buried in the seabed from late summer to spring. The presence of pilchard and anchovy confirmed their re-establishment in the Southern North Sea and Wadden Sea. The abundance of pelagic fish exceeded the biomass of demersal fish in the western Wadden Sea by an order of magnitude. This finding is relevant for ecosystem studies. The fact that this study suggests that small pelagics outnumber demersal species to such a large extent calls for a rethinking of the allocation of monitoring effort in the Dutch coastal zone.

  5. Attenuation of species abundance distributions by sampling.

    PubMed

    Shimadzu, Hideyasu; Darnell, Ross

    2015-04-01

    Quantifying biodiversity aspects such as species presence/ absence, richness and abundance is an important challenge to answer scientific and resource management questions. In practice, biodiversity can only be assessed from biological material taken by surveys, a difficult task given limited time and resources. A type of random sampling, or often called sub-sampling, is a commonly used technique to reduce the amount of time and effort for investigating large quantities of biological samples. However, it is not immediately clear how (sub-)sampling affects the estimate of biodiversity aspects from a quantitative perspective. This paper specifies the effect of (sub-)sampling as attenuation of the species abundance distribution (SAD), and articulates how the sampling bias is induced to the SAD by random sampling. The framework presented also reveals some confusion in previous theoretical studies. PMID:26064626

  6. Attenuation of species abundance distributions by sampling

    PubMed Central

    Shimadzu, Hideyasu; Darnell, Ross

    2015-01-01

    Quantifying biodiversity aspects such as species presence/ absence, richness and abundance is an important challenge to answer scientific and resource management questions. In practice, biodiversity can only be assessed from biological material taken by surveys, a difficult task given limited time and resources. A type of random sampling, or often called sub-sampling, is a commonly used technique to reduce the amount of time and effort for investigating large quantities of biological samples. However, it is not immediately clear how (sub-)sampling affects the estimate of biodiversity aspects from a quantitative perspective. This paper specifies the effect of (sub-)sampling as attenuation of the species abundance distribution (SAD), and articulates how the sampling bias is induced to the SAD by random sampling. The framework presented also reveals some confusion in previous theoretical studies. PMID:26064626

  7. Higher parasite richness, abundance and impact in native versus introduced cichlid fishes.

    PubMed

    Roche, Dominique G; Leung, Brian; Franco, Edgar F Mendoza; Torchin, Mark E

    2010-11-01

    Empirical studies suggest that most exotic species have fewer parasite species in their introduced range relative to their native range. However, it is less clear how, ecologically, the loss of parasite species translates into a measurable advantage for invaders relative to native species in the new community. We compared parasitism at three levels (species richness, abundance and impact) for a pair of native and introduced cichlid fishes which compete for resources in the Panama Canal watershed. The introduced Nile tilapia, Oreochromis niloticus, was infected by a single parasite species from its native range, but shared eight native parasite species with the native Vieja maculicauda. Despite acquiring new parasites in its introduced range, O. niloticus had both lower parasite species richness and lower parasite abundance compared with its native competitor. There was also a significant negative association between parasite load (abundance per individual fish) and host condition for the native fish, but no such association for the invader. The effects of parasites on the native fish varied across sites and types of parasites, suggesting that release from parasites may benefit the invader, but that the magnitude of release may depend upon interactions between the host, parasites and the environment. PMID:20600073

  8. Distribution and abundance of fish larvae in the northern Ionian Sea (Eastern Mediterranean)

    NASA Astrophysics Data System (ADS)

    Granata, Antonia; Cubeta, Annaluce; Minutoli, Roberta; Bergamasco, Alessandro; Guglielmo, Letterio

    2011-09-01

    The purpose of this paper was to study the spatial distribution, abundance and composition of fish larvae in the northern Ionian Sea. Samples were collected to the 600 m depth with an electronic multinet BIONESS during the "INTERREG Italia-Grecia" oceanographic cruise carried out in March 2000 off the Apulian Italian coast. A total of 46 species of teleost early stages were collected, belonging to 38 genera and 22 families. Over 52% of the larvae identified were mesopelagic species, almost 27% were demersal and about 21% pelagic. A total of 307 myctophids, 69 clupeids and 61 gadid post-larvae dominated the community. Benthosema glaciale (mean 6.1 mm SL) was the most abundant species (21.6%), the most frequent in the samples (28.8%), and dominant in the whole study area (mean 1.4 ind/100 m3). Particular attention was given to the horizontal and vertical distribution and abundance of the three dominant post-larval species: Benthosema glaciale, Sprattus sprattus sprattus and Notoscopelus elongatus. The Pearson coefficient ( R = 0.734) showed a high correlation between total zooplankton and fish larval assemblages in terms of spatial distribution abundance values. Regarding the vertical distribution of fish larvae, Sorensen's index ( S = 0.69) showed that fish larvae and total zooplankton abundance peaks co-occurred along the water column.

  9. Fishers' knowledge identifies environmental changes and fish abundance trends in impounded tropical rivers.

    PubMed

    Hallwass, Gustavo; Lopes, Priscila F; Juras, Anastácio A; Silvano, Renato A M

    2013-03-01

    The long-term impacts of large hydroelectric dams on small-scale fisheries in tropical rivers are poorly known. A promising way to investigate such impacts is to compare and integrate the local ecological knowledge (LEK) of resource users with biological data for the same region. We analyzed the accuracy of fishers' LEK to investigate fisheries dynamics and environmental changes in the Lower Tocantins River (Brazilian Amazon) downstream from a large dam. We estimated fishers' LEK through interviews with 300 fishers in nine villages and collected data on 601 fish landings in five of these villages, 22 years after the dam's establishment (2006-2008). We compared these two databases with each other and with data on fish landings from before the dam's establishment (1981) gathered from the literature. The data obtained based on the fishers' LEK (interviews) and from fisheries agreed regarding the primary fish species caught, the most commonly used type of fishing gear (gill nets) and even the most often used gill net mesh sizes but disagreed regarding seasonal fish abundance. According to the interviewed fishers, the primary environmental changes that occurred after the impoundment were an overall decrease in fish abundance, an increase in the abundance of some fish species and, possibly, the local extinction of a commercial fish species (Semaprochilodus brama). These changes were corroborated by comparing fish landings sampled before and 22 years after the impoundment, which indicated changes in the composition of fish landings and a decrease in the total annual fish production. Our results reinforce the hypothesis that large dams may adversely affect small-scale fisheries downstream and establish a feasible approach for applying fishers' LEK to fisheries management, especially in regions with a low research capacity. PMID:23634590

  10. Parasite abundance and its determinants in fishes from Brazil: an eco-epidemiological approach.

    PubMed

    Amarante, Cristina Fernandes do; Tassinari, Wagner de Souza; Luque, Jose Luis; Pereira, Maria Julia Salim

    2016-06-01

    The variability in parasite abundance has an ecological basis; however, from an epidemiological point of view, the contribution of factors inherent to the host to the variability in parasite abundance remains an open question. A database consisting of 3,746 specimens of 73 fish species was used to verify the relation between the distribution of parasite abundance in fishes and a set of biotic factors inherent to the hosts. Classical and mixed Poisson regression models were constructed. Prevalence ratios (PR) and their respective 95% confidence intervals were estimated. The parasite abundance was significantly higher in female hosts, nonschooling species, species from benthopelagic and pelagic habitats, and fishes with greater body length. Overall, these results suggest that the variability in the abundance of infection is an attribute of the parasite species. Although the results are biologically plausible, important gaps may still exist and should be explored to better understand the variations in parasite abundance, which has great relevance in epidemiological studies. We reinforce the importance of choosing the statistical model most appropriate for the nature of the data to avoid spurious results, especially when the autocorrelation in the data is not taken into account. PMID:27276671

  11. The role of carrion supply in the abundance of deep-water fish off California.

    PubMed

    Drazen, Jeffrey C; Bailey, David M; Ruhl, Henry A; Smith, Kenneth L

    2012-01-01

    Few time series of deep-sea systems exist from which the factors affecting abyssal fish populations can be evaluated. Previous analysis showed an increase in grenadier abundance, in the eastern North Pacific, which lagged epibenthic megafaunal abundance, mostly echinoderms, by 9-20 months. Subsequent diet studies suggested that carrion is the grenadier's most important food. Our goal was to evaluate if changes in carrion supply might drive the temporal changes in grenadier abundance. We analyzed a unique 17 year time series of abyssal grenadier abundance and size, collected at Station M (4100 m, 220 km offshore of Pt. Conception, California), and reaffirmed the increase in abundance and also showed an increase in mean size resulting in a ∼6 fold change in grenadier biomass. We compared this data with abundance estimates for surface living nekton (pacific hake and jack mackerel) eaten by the grenadiers as carrion. A significant positive correlation between Pacific hake (but not jack mackerel) and grenadiers was found. Hake seasonally migrate to the waters offshore of California to spawn. They are the most abundant nekton species in the region and the target of the largest commercial fishery off the west coast. The correlation to grenadier abundance was strongest when using hake abundance metrics from the area within 100 nmi of Station M. No significant correlation between grenadier abundance and hake biomass for the entire California current region was found. Given the results and grenadier longevity, migration is likely responsible for the results and the location of hake spawning probably is more important than the size of the spawning stock in understanding the dynamics of abyssal grenadier populations. Our results suggest that some abyssal fishes' population dynamics are controlled by the flux of large particles of carrion. Climate and fishing pressures affecting epipelagic fish stocks could readily modulate deep-sea fish dynamics. PMID:23133679

  12. The Role of Carrion Supply in the Abundance of Deep-Water Fish off California

    PubMed Central

    Drazen, Jeffrey C.; Bailey, David M.; Ruhl, Henry A.; Smith, Kenneth L.

    2012-01-01

    Few time series of deep-sea systems exist from which the factors affecting abyssal fish populations can be evaluated. Previous analysis showed an increase in grenadier abundance, in the eastern North Pacific, which lagged epibenthic megafaunal abundance, mostly echinoderms, by 9–20 months. Subsequent diet studies suggested that carrion is the grenadier's most important food. Our goal was to evaluate if changes in carrion supply might drive the temporal changes in grenadier abundance. We analyzed a unique 17 year time series of abyssal grenadier abundance and size, collected at Station M (4100 m, 220 km offshore of Pt. Conception, California), and reaffirmed the increase in abundance and also showed an increase in mean size resulting in a ∼6 fold change in grenadier biomass. We compared this data with abundance estimates for surface living nekton (pacific hake and jack mackerel) eaten by the grenadiers as carrion. A significant positive correlation between Pacific hake (but not jack mackerel) and grenadiers was found. Hake seasonally migrate to the waters offshore of California to spawn. They are the most abundant nekton species in the region and the target of the largest commercial fishery off the west coast. The correlation to grenadier abundance was strongest when using hake abundance metrics from the area within 100 nmi of Station M. No significant correlation between grenadier abundance and hake biomass for the entire California current region was found. Given the results and grenadier longevity, migration is likely responsible for the results and the location of hake spawning probably is more important than the size of the spawning stock in understanding the dynamics of abyssal grenadier populations. Our results suggest that some abyssal fishes' population dynamics are controlled by the flux of large particles of carrion. Climate and fishing pressures affecting epipelagic fish stocks could readily modulate deep-sea fish dynamics. PMID:23133679

  13. Life history traits and exploitation affect the spatial mean-variance relationship in fish abundance.

    PubMed

    Kuo, Ting-chun; Mandal, Sandip; Yamauchi, Atsushi; Hsieh, Chih-hao

    2016-05-01

    Fishing is expected to alter the spatial heterogeneity of fishes. As an effective index to quantify spatial heterogeneity, the exponent b in Taylor's power law (V = aMb) measures how spatial variance (V) varies with changes in mean abundance (M) of a population, with larger b indicating higher spatial aggregation potential (i.e., more heterogeneity). Theory predicts b is related with life history traits, but empirical evidence is lacking. Using 50-yr spatiotemporal data from the California Current Ecosystem, we examined fishing and life history effects on Taylor's exponent by comparing spatial distributions of exploited and unexploited fishes living in the same environment. We found that unexploited species with smaller size and generation time exhibit larger b, supporting theoretical prediction. In contrast, this relationship in exploited species is much weaker, as the exponents of large exploited species were higher than unexploited species with similar traits. Our results suggest that fishing may increase spatial aggregation potential of a species, likely through degrading their size/age structure. Results of moving-window cross-correlation analyses on b vs. age structure indices (mean age and age evenness) for some exploited species corroborate our findings. Furthermore, through linking our findings to other fundamental ecological patterns (occupancy-abundance and size-abundance relationships), we provide theoretical arguments for the usefulness of monitoring the exponent b for management purposes. We propose that age/size-truncated species might have lower recovery rate in spatial occupancy, and the spatial variance-mass relationship of a species might be non-linear. Our findings provide theoretical basis explaining why fishery management strategy should be concerned with changes to the age and spatial structure of exploited fishes. PMID:27349101

  14. Bayesian change point analysis of abundance trends for pelagic fishes in the upper San Francisco Estuary

    USGS Publications Warehouse

    Thompson, James R.; Kimmerer, Wim J.; Brown, Larry R.; Newman, Ken B.; Mac Nally, Ralph; Bennett, William A.; Feyrer, Frederick; Fleishman, Erica

    2010-01-01

    We examined trends in abundance of four pelagic fish species (delta smelt, longfin smelt, striped bass, and threadfin shad) in the upper San Francisco Estuary, California, USA, over 40 years using Bayesian change point models. Change point models identify times of abrupt or unusual changes in absolute abundance (step changes) or in rates of change in abundance (trend changes). We coupled Bayesian model selection with linear regression splines to identify biotic or abiotic covariates with the strongest associations with abundances of each species. We then refitted change point models conditional on the selected covariates to explore whether those covariates could explain statistical trends or change points in species abundances. We also fitted a multispecies change point model that identified change points common to all species. All models included hierarchical structures to model data uncertainties, including observation errors and missing covariate values. There were step declines in abundances of all four species in the early 2000s, with a likely common decline in 2002. Abiotic variables, including water clarity, position of the 2‰ isohaline (X2), and the volume of freshwater exported from the estuary, explained some variation in species' abundances over the time series, but no selected covariates could explain statistically the post-2000 change points for any species.

  15. Abundance of introduced species at home predicts abundance away in herbaceous communities

    USGS Publications Warehouse

    Firn, Jennifer; Moore, Joslin L.; MacDougall, Andrew S.; Borer, Elizabeth T.; Seabloom, Eric W.; HilleRisLambers, Janneke; Harpole, W. Stanley; Cleland, Elsa E.; Brown, Cynthia S.; Knops, Johannes M.H.; Prober, Suzanne M.; Pyke, David A.; Farrell, Kelly A.; Bakker, John D.; O'Halloran, Lydia R.; Adler, Peter B.; Collins, Scott L.; D'Antonio, Carla M.; Crawley, Michael J.; Wolkovich, Elizabeth M.; La Pierre, Kimberly J.; Melbourne, Brett A.; Hautier, Yann; Morgan, John W.; Leakey, Andrew D.B.; Kay, Adam; McCulley, Rebecca; Davies, Kendi F.; Stevens, Carly J.; Chu, Cheng-Jin; Holl, Karen D.; Klein, Julia A.; Fay, Phillip A.; Hagenah, Nicole; Kirkman, Kevin P.; Buckley, Yvonne M.

    2011-01-01

    Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites - grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes.

  16. Measuring marine fish biodiversity: temporal changes in abundance, life history and demography

    PubMed Central

    Hutchings, Jeffrey A; Baum, Julia K

    2005-01-01

    Patterns in marine fish biodiversity can be assessed by quantifying temporal variation in rate of population change, abundance, life history and demography concomitant with long-term reductions in abundance. Based on data for 177 populations (62 species) from four north-temperate oceanic regions (Northeast Atlantic and Pacific, Northwest Atlantic, North mid-Atlantic), 81% of the populations in decline prior to 1992 experienced reductions in their rate of loss thereafter; species whose rate of population decline accelerated after 1992 were predominantly top predators such as Atlantic cod (Gadus morhua), sole (Solea solea) and pelagic sharks. Combining population data across regions and species, marine fish have declined 35% since 1978 and are currently less than 70% of recorded maxima; demersal species are generally at historic lows, pelagic species are generally stable or increasing in abundance. Declines by demersal species have been associated with substantive increases in pelagic species, a pattern consistent with the hypothesis that increases in the latter may be attributable to reduced predation mortality. There is a need to determine the consequences to population growth effected by the reductions in age (21%) and size (13%) at maturity and in mean age (5%) and size (18%) of spawners, concomitant with population decline. We conclude that reductions in the rate of population decline, in the absence of targets for population increase, will be insufficient to effect a recovery of marine fish biodiversity, and that great care must be exercised when interpreting multi-species patterns in abundance. Of fundamental importance is the need to explain the geographical, species-specific and habitat biases that pervade patterns of marine fish recovery and biodiversity. PMID:15814348

  17. Flow and habitat effects on juvenile fish abundance in natural and altered flow regimes

    USGS Publications Warehouse

    Freeman, Mary C.; Bowen, Z.H.; Bovee, K.D.; Irwin, E.R.

    2001-01-01

    Conserving biological resources native to large river systems increasingly depends on how flow-regulated segments of these rivers are managed. Improving management will require a better understanding of linkages between river biota and temporal variability of flow and instream habitat. However, few studies have quantified responses of native fish populations to multiyear (>2 yr) patterns of hydrologic or habitat variability in flow-regulated systems. To provide these data, we quantified young-of-year (YOY) fish abundance during four years in relation to hydrologic and habitat variability in two segments of the Tallapoosa River in the southeastern United States. One segment had an unregulated flow regime, whereas the other was flow-regulated by a peak-load generating hydropower dam. We sampled fishes annually and explored how continuously recorded flow data and physical habitat simulation models (PHABSIM) for spring (April-June) and summer (July-August) preceding each sample explained fish abundances. Patterns of YOY abundance in relation to habitat availability (median area) and habitat persistence (longest period with habitat area continuously above the long-term median area) differed between unregulated and flow-regulated sites. At the unregulated site, YOY abundances were most frequently correlated with availability of shallow-slow habitat in summer (10 species) and persistence of shallow-slow and shallow-fast habitat in spring (nine species). Additionally, abundances were negatively correlated with 1-h maximum flow in summer (five species). At the flow-regulated site, YOY abundances were more frequently correlated with persistence of shallow-water habitats (four species in spring; six species in summer) than with habitat availability or magnitude of flow extremes. The associations of YOY with habitat persistence at the flow-regulated site corresponded to the effects of flow regulation on habitat patterns. Flow regulation reduced median flows during spring and

  18. Modeling species-abundance relationships in multi-species collections

    USGS Publications Warehouse

    Peng, S.; Yin, Z.; Ren, H.; Guo, Q.

    2003-01-01

    Species-abundance relationship is one of the most fundamental aspects of community ecology. Since Motomura first developed the geometric series model to describe the feature of community structure, ecologists have developed many other models to fit the species-abundance data in communities. These models can be classified into empirical and theoretical ones, including (1) statistical models, i.e., negative binomial distribution (and its extension), log-series distribution (and its extension), geometric distribution, lognormal distribution, Poisson-lognormal distribution, (2) niche models, i.e., geometric series, broken stick, overlapping niche, particulate niche, random assortment, dominance pre-emption, dominance decay, random fraction, weighted random fraction, composite niche, Zipf or Zipf-Mandelbrot model, and (3) dynamic models describing community dynamics and restrictive function of environment on community. These models have different characteristics and fit species-abundance data in various communities or collections. Among them, log-series distribution, lognormal distribution, geometric series, and broken stick model have been most widely used.

  19. Abandoning small-scale fish farming in western Kenya leads to higher malaria vector abundance.

    PubMed

    Howard, Annabel F V; Omlin, Francois X

    2008-01-01

    Fishponds become abandoned due to lack of access to both young fish and technical support and faster economic returns from other activities. Certain conditions found in abandoned fishponds, such as absence of fish and presence of aquatic vegetation, are conducive to the presence of malaria vectors. We conducted a district-wide fishpond census to determine the maintenance status and mosquito populations of fishponds in Kisii Central District in western Kenya. Two hundred and sixty one fishponds were found, 186 active (fish present) and 75 abandoned (fish absent). Vegetation was not significantly associated with the distribution of Anopheles gambiae s.l., Anopheles funestus or culicines (Diptera: Culicidae) in active or abandoned ponds. The presence of fish, however, correlated significantly with the distribution of all mosquito species, with significantly higher mosquito densities in abandoned fishponds. An. gambiae s.l. was the most abundant mosquito species found in both active and abandoned ponds, being proportionally more abundant in the abandoned ponds. The proportion of An. funestus increased with altitude. Following the census the demand for fish to re-stock abandoned ponds rose by 67% when compared to the same time period in the previous year. This study highlights the potential public health problems associated with the abandonment of small-scale fish farming in the highlands of western Kenya. PMID:18068136

  20. Distribution, abundance, diversity and habitat associations of fishes across a bioregion experiencing rapid coastal development

    NASA Astrophysics Data System (ADS)

    McLean, Dianne L.; Langlois, Tim J.; Newman, Stephen J.; Holmes, Thomas H.; Birt, Matthew J.; Bornt, Katrina R.; Bond, Todd; Collins, Danielle L.; Evans, Scott N.; Travers, Michael J.; Wakefield, Corey B.; Babcock, Russ C.; Fisher, Rebecca

    2016-09-01

    Knowledge of the factors that influence spatial patterns in fish abundance, distribution and diversity are essential for informing fisheries and conservation management. The present study was conducted in the nearshore Pilbara bioregion of north-western Australia where the dynamic marine environment is characterised by large embayments, numerous islands and islets, coexisting with globally significant petrochemical and mineral industries. Within Western Australia, this nearshore bioregion has high biodiversity and is considered to play an essential role in the recruitment of species of commercial importance. To better inform future investigations into both ecological processes and planning scenarios for management, a rapid assessment of the distribution, abundance and associations with nearshore habitats of fishes across the region was conducted. Baited remote underwater stereo-video systems (stereo-BRUVs) were used to simultaneously sample the fish assemblage and habitat composition. Generalised additive mixed models (GAMMs) were used to determine whether the abundance of fishes were related to habitat and a range of environmental variables (visibility, depth, distance to 30 m and 200 m depth isobars, boat ramps and the nearest large embayment (Exmouth Gulf). A diverse fish assemblage comprising 343 species from 58 families was recorded. The abundance and distribution patterns of fishery-target species and of the five most common and abundant species and families were linked positively with areas of high relief, hard coral cover, reef and macroalgae and negatively with the distance to the nearest oceanic waters (200 m depth isobar). This study provides information that can contribute to future marine spatial planning scenarios for management of the Pilbara using a unique, analytical approach that has broad application in biogeography.

  1. Distribution and Abundance of Opisthorchis viverrini Metacercariae in Cyprinid Fish in Northeastern Thailand

    PubMed Central

    Onsurathum, Sudarat; Boonmars, Thidarut; Pinlaor, Porntip; Hongsrichan, Nuttanan; Chaidee, Apisit; Haonon, Ornuma; Limviroj, Wutipong; Tesana, Smarn; Kaewkes, Sasithorn; Sithithaworn, Paiboon

    2013-01-01

    To increase public health awareness for prevention of opisthorchiasis caused by eating raw freshwater fish, the distribution and abundance of Opisthorchis viverrini metacercariae (OV MC) was investigated in freshwater fish obtained from 20 provinces in northeastern Thailand between April 2011 and February 2012. A cross-sectional survey was conducted on 12,890 fish consisting of 13 species randomly caught from 26 rivers, 10 dams, and 38 ponds/lakes. Fish, were collected in each of the rainy and winter seasons from each province. Fish were identified, counted, weighed, and digested using pepsin-HCl. Samples were examined for OV MC by a sedimentation method, and metacercariae were identified under a stereomicroscope. OV MC were found in 6 species of fish; i.e., Cyclocheilichthys armatus, Puntius orphoides, Hampala dispar, Henicorhynchus siamensis, Osteochilus hasselti, and Puntioplites proctozysron from localities in 13 provinces. Among the sites where OV MC-infected fish were found, 70.0% were dams, 23.7% were ponds/lakes, and 7.7% were rivers. The mean intensity of OV MC ranged from 0.01 to 6.5 cysts per fish (or 1.3-287.5 cysts per kg of fish). A high mean intensity of OV MC per fish (>3 cysts) was found in 5 provinces: Amnat Charoen (6.5 cysts), Nakhon Phanom (4.3), Mukdahan (4.1), Khon Kaen, (3.5) and Si Sa Ket (3.4). In conclusion, OV MC are prevalent in natural cyprinid fish, with the infection rate varying according to fish species and habitats. PMID:24516277

  2. Seasonal distribution and abundance of fishes and decapod crustaceans in a Cape Cod estuary

    USGS Publications Warehouse

    Able, K.W.; Fahay, M.P.; Heck, K.L.; Roman, C.T.; Lazzari, M.A.; Kaiser, S.C.

    2002-01-01

    Sampling in several habitat types (sand/mud, eelgrass, sand, gravel, macroalgae/mud) during all seasons with a variety of gears in Nauset Marsh, Massachusetts during 1985-1987 found a fauna consisting of 35 fish and 10 decapod crustacean species. Although most of the abundant species were found in several habitat types, species richness and habitat use appeared to be highest for vegetated habitats (eelgrass, macroalgae). The fishes and decapods were numerically dominated by cold-water taxa; however, numerous fish species, represented by rare individuals of predominantly southern forms, enriched the fauna. Species composition of Nauset Marsh could be distinguished from estuaries south of Cape Cod and even from the south shore of the cape. Both fishes and decapods were most abundant during the summer, apparently due to the contributions from spring and summer spawning in the estuary and the adjacent Atlantic Ocean. The location of Nauset Marsh and other estuaries on Cape Cod provide a unique opportunity to evaluate the importance of this region as a faunal boundary to estuarine species.

  3. Latitudinal and bathymetric patterns in the distribution and abundance of mesopelagic fish in the Scotia Sea

    NASA Astrophysics Data System (ADS)

    Collins, Martin A.; Stowasser, Gabriele; Fielding, Sophie; Shreeve, Rachel; Xavier, José C.; Venables, Hugh J.; Enderlein, Peter; Cherel, Yves; Van de Putte, Anton

    2012-01-01

    Mesopelagic fish are a key component of the pelagic ecosystem throughout the world's oceans. Opening and closing nets were used to investigate patterns in the distribution and abundance of mesopelagic fish from the surface to 1000 m on a series of transects across the Scotia Sea from the ice-edge to the Antarctic Polar Front. A total of 141 non-target net hauls were undertaken during three cruises (Nov 2006, Jan 2008 and Mar 2009), with 7852 teleost fish captured, representing 43 species in 17 families. A further 1517 fish were caught in targeted net hauls. The dominant families were the Myctophidae (6961 specimens; 21 species) and Bathylagidae (1467 specimens; 4 species). Few fish were caught in the upper 400 m during daylight, which was attributed to a combination of net avoidance and diurnal vertical migration. Species composition was linked to depth and location and was closely associated with oceanographic features. Diversity was lowest in cold water at the most southerly stations, which were dominated by Electrona antarctica, Gymnoscopelus braueri and Bathylagus antarcticus. Further north, diversity increased with the addition of species such as Krefftichthys anderssoni, Protomyctophum bolini and Electrona carlsbergi. The depth integrated biomass of myctophids was similar across the latitudinal transect and produced an estimate of 4.5 million tonnes in the Scotia Sea. Bathylagids were patchily distributed, but were abundant in the lower mesopelagic zone (>400 m) and are potentially significant zooplankton consumers. Given the biomass of the myctophids and bathylagids coupled with the vertical migrations of many species, these fish are likely to play a significant role in carbon export from the surface waters to the deep ocean.

  4. Effects of Gear Restriction on the Abundance of Juvenile Fishes along Sandy Beaches in Hawai'i.

    PubMed

    Donovan, Mary K; Friedlander, Alan M; Usseglio, Paolo; Goodell, Whitney; Iglesias, Ily; Schemmel, Eva M; Stamoulis, Kostantinos A; Filous, Alexander; Giddens, Jonatha; Kamikawa, Keith; Koike, Haruko; McCoy, Kaylyn; Wall, Christopher B

    2016-01-01

    In 2007, due to growing concerns of declines in nearshore fisheries in Hawai'i, a ban on gillnets was implemented in designated areas around the island of O'ahu in the main Hawaiian Islands. Utilizing a 17 year time-series of juvenile fish abundance beginning prior to the implementation of the gillnet ban, we examined the effects of the ban on the abundance of juveniles of soft-bottom associated fish species. Using a Before-After-Control-Impact (BACI) sampling design, we compared the abundance of targeted fishery species in a bay where gillnet fishing was banned (Kailua, O'ahu), and an adjacent bay where fishing is still permitted (Waimānalo, O'ahu). Our results show that when multiple juvenile fish species were combined, abundance declined over time in both locations, but the pattern varied for each of the four species groups examined. Bonefishes were the only species group with a significant BACI effect, with higher abundance in Kailua in the period after the gillnet ban. This study addressed a need for scientific assessment of a fisheries regulation that is rarely possible due to lack of quality data before enactment of such restrictions. Thus, we developed a baseline status of juveniles of an important fishery species, and found effects of a fishery management regulation in Hawai'i. PMID:27171404

  5. Effects of Gear Restriction on the Abundance of Juvenile Fishes along Sandy Beaches in Hawai‘i

    PubMed Central

    Friedlander, Alan M.; Usseglio, Paolo; Goodell, Whitney; Iglesias, Ily; Schemmel, Eva M.; Stamoulis, Kostantinos A.; Filous, Alexander; Giddens, Jonatha; Kamikawa, Keith; Koike, Haruko; McCoy, Kaylyn; Wall, Christopher B.

    2016-01-01

    In 2007, due to growing concerns of declines in nearshore fisheries in Hawai‘i, a ban on gillnets was implemented in designated areas around the island of O‘ahu in the main Hawaiian Islands. Utilizing a 17 year time-series of juvenile fish abundance beginning prior to the implementation of the gillnet ban, we examined the effects of the ban on the abundance of juveniles of soft-bottom associated fish species. Using a Before-After-Control-Impact (BACI) sampling design, we compared the abundance of targeted fishery species in a bay where gillnet fishing was banned (Kailua, O‘ahu), and an adjacent bay where fishing is still permitted (Waimānalo, O‘ahu). Our results show that when multiple juvenile fish species were combined, abundance declined over time in both locations, but the pattern varied for each of the four species groups examined. Bonefishes were the only species group with a significant BACI effect, with higher abundance in Kailua in the period after the gillnet ban. This study addressed a need for scientific assessment of a fisheries regulation that is rarely possible due to lack of quality data before enactment of such restrictions. Thus, we developed a baseline status of juveniles of an important fishery species, and found effects of a fishery management regulation in Hawai‘i. PMID:27171404

  6. Influence of nursery microhabitats on the future abundance of a coral reef fish.

    PubMed

    Wilson, Shaun K; Depczynski, Martial; Fulton, Christopher J; Holmes, Thomas H; Radford, Ben T; Tinkler, Paul

    2016-08-17

    Species habitat associations are often complex, making it difficult to assess their influence on populations. Among coral reef fishes, habitat requirements vary among species and with ontogeny, but the relative importance of nursery and adult-preferred habitats on future abundances remain unclear. Moreover, adult populations may be influenced by recruitment of juveniles and assessments of habitat importance should consider relative effects of juvenile abundance. We conducted surveys across 16 sites and 200 km of reef to identify the microhabitat preferences of juveniles, sub-adults and adults of the damselfish Pomacentrus moluccensis Microhabitat preferences at different life-history stages were then combined with 6 years of juvenile abundance and microhabitat availability data to show that the availability of preferred juvenile microhabitat (corymbose corals) at the time of settlement was a strong predictor of future sub-adult and adult abundance. However, the influence of nursery microhabitats on future population size differed spatially and at some locations abundance of juveniles and adult microhabitat (branching corals) were better predictors of local populations. Our results demonstrate that while juvenile microhabitats are important nurseries, the abundance of coral-dependent fishes is not solely dependent on these microhabitats, especially when microhabitats are readily available or following large influxes of juveniles. PMID:27534954

  7. ABUNDANT OR RARE? A HYBRID APPROACH FOR DETERMINING SPECIES RELATIVE ABUNDANCE AT AN ECOREGOIONAL SCALE - 2014

    EPA Science Inventory

    Everyone knows what abundant and rare species are, but quantifying the concept proves elusive. As part of an EPA/USGS project to assess near-coastal species vulnerability to climate change affects, we designed a hybrid approach to determine species relative abundance at an ecoreg...

  8. ABUNDANT OR RARE? A HYBRID APPROACH FOR DETERMINING SPECIES RELATIVE ABUNDANCE AT AN ECOREGOIONAL SCALE

    EPA Science Inventory

    Everyone knows what abundant and rare species are, but quantifying the concept proves elusive. As part of an EPA/USGS project to assess near-coastal species vulnerability to climate change affects, we designed a hybrid approach to determine species relative abundance at an ecoreg...

  9. Distribution and abundance of nonnative fishes in streams of the western United States

    USGS Publications Warehouse

    Schade, C.B.; Bonar, Scott A.

    2005-01-01

    This report presents data from one of the largest standardized stream surveys conducted in he western United States, which shows that one of every four individual fish in streams of 12 western states are nonnative. The states surveyed included Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington, and Wyoming. The most widely distributed and abundant nonnative fishes in the western USA were brook trout Salvelinus fontinalis, brown trout Salmo trutta, rainbow trout Oncorhynchus mykiss, common carp Cyprinus carpio, smallmouth bass Micropterus dolomieu, largemouth bass M. salmoides, green sunfish Lepomis cyanellus, fathead minnow Pimephales promelas, yellow perch Percaflavescens, yellow bullhead Ameiurus natalis, cutthroat trout O. clarkii, western mosquitofish Gambusia affinis, golden shiner Notemigonus crysoleucas, channel catfish Ictalurus punctatus, and red shiner Cyprinella lutrensis. The greatest abundance and distribution of nonnative fishes was in interior states, and the most common nonnatives were introduced for angling. Nonnative fishes were widespread in pristine to highly disturbed streams influenced by all types of land use practices. We present ranges in water temperature, flow, stream order, riparian cover, human disturbance, and other environmental conditions where the 10 most common introduced species were found. Of the total western U.S. stream length bearing fish, 50.1% contained nonnative fishes while 17.9% contained physical environment that was ranked highly or moderately disturbed by humans. Introduced fishes can adversely affect stream communities, and they are much more widespread in western U.S. streams than habitat destruction. The widespread distribution and high relative abundance of nonnative fishes and their documented negative effects suggest their management and control should elicit at least as much attention as habitat preservation in the protection of native western U.S. stream

  10. Predictability of reef fish diversity and abundance using remote sensing data in Diego Garcia (Chagos Archipelago)

    NASA Astrophysics Data System (ADS)

    Purkis, S. J.; Graham, N. A. J.; Riegl, B. M.

    2008-03-01

    The diversity, abundance and distribution of reef fish are related to heterogeneity and physical complexity of benthic habitat. However, the field effort required to evaluate these aspects of the benthos in situ, at the scale of entire reefscapes, is greatly constrained by logistical and resource limitations. With moderate ground truthing, both substratum type and seabed topography are amenable to monitoring using satellite data. Here, remote sensing imagery was used to resolve the bathymetry and benthic character of a reef system in Diego Garcia (British Indian Ocean Territory). Replicate fish counts were made at seven measurement stations across the study area using visual census. Monte Carlo simulation revealed that species richness and abundance of several guilds and size groupings of reef fish appraised in situ were correlated with the satellite-derived seabed parameters over areas of seafloor as large as 5,030 m2. The study suggests that satellite remote sensing is capable of predicting habitat complexity at a scale relevant to fish. Furthermore, as larger size classes of fish were better predicted with the satellite habitat complexity data, this technique could be used to predict fish stocks and identify potential sites for marine protected areas where intensive field surveys are not practical.

  11. Habitat Selection and Temporal Abundance Fluctuations of Demersal Cartilaginous Species in the Aegean Sea (Eastern Mediterranean)

    PubMed Central

    Maravelias, Christos D.; Tserpes, George; Pantazi, Maria; Peristeraki, Panagiota

    2012-01-01

    Predicting the occurrence of keystone top predators in a multispecies marine environment, such as the Mediterranean Sea, can be of considerable value to the long-term sustainable development of the fishing industry and to the protection of biodiversity. We analysed fisheries independent scientific bottom trawl survey data of two of the most abundant cartilaginous fish species (Scyliorhinus canicula, Raja clavata) in the Aegean Sea covering an 11-year sampling period. The current findings revealed a declining trend in R. clavata and S. canicula abundance from the late ′90 s until 2004. Habitats with the higher probability of finding cartilaginous fish present were those located in intermediate waters (depth: 200–400 m). The present results also indicated a preferential species' clustering in specific geographic and bathymetric regions of the Aegean Sea. Depth appeared to be one of the key determining factors for the selection of habitats for all species examined. With cartilaginous fish species being among the more biologically sensitive fish species taken in European marine fisheries, our findings, which are based on a standardized scientific survey, can contribute to the rational exploitation and management of their stocks by providing important information on temporal abundance trends and habitat preferences. PMID:22536389

  12. Hydroacoustic estimates of fish abundance. Reservoir vital signs monitoring, 1990

    SciTech Connect

    Wilson, W.K.

    1991-03-01

    Hydroacoustics, as defined in the context of this report, is the use of a scientific sonar system to determine fish densities with respect to numbers and biomass. These two parameters provide a method of monitoring reservoir fish populations and detecting gross changes in the ecosystem. With respect to southeastern reservoirs, hydroacoustic surveys represent a new method of sampling open water areas and the best technology available. The advantages of this technology are large amounts of data can be collected in a relatively short period of time allowing improved statistical interpretation and data comparison, the pelagic (open water) zone can be sampled efficiently regardless of depth, and sampling is nondestructive and noninvasive with neither injury to the fish nor alteration of the environment. Hydroacoustics cannot provide species identification and related information on species composition or length/weight relationships. Also, sampling is limited to a minimum depth of ten feet which precludes the use of this equipment for sampling shallow shoreline areas. The objective of this study is to use hydroacoustic techniques to estimate fish standing stocks (i.e., numbers and biomass) in several areas of selected Tennessee Valley Reservoirs as part of a base level monitoring program to assess long-term changes in reservoir water quality.

  13. Value-added products from underutilized fish species.

    PubMed

    Venugopal, V; Shahidi, F

    1995-09-01

    Fish is a rich source of easily digestible protein that also provides polyunsaturated fatty acids, vitamins, and minerals for human nutrition. Nonetheless, a large proportion of total landed fish remains unused due to inherent problems related to unattractive color, flavor, texture, small size, and high fat content. Most of these underutilized fish belong to the abundantly available pelagic species, which are landed as bycatch, and some are unconventional species such as krill. Although some species are used industrially for fish meal manufacture, a need for their conservation and utilization for human consumption has been recognized in order to prevent post-harvest fishery losses. Recovery of flesh by mechanical deboning and development of value-added products are probably the most promising approaches. This article discusses various possibilities for product development using mince from low-cost fishery resources. These include surimi and surimi-based products, sausages, fermented products, protein concentrates and hydrolysates, extruded products, and biotechnological possibilities. The dual advantages of this approach, namely, finding ways for better utilization of low-value fish species and providing protein- rich convenience foods, have been pointed out. However, the key to the success of this approach depends largely on the market strategies utilized. PMID:8573282

  14. Seasonal variation of assemblage and feeding guild structure of fish species in a boreal tidal basin

    NASA Astrophysics Data System (ADS)

    Kellnreitner, Florian; Pockberger, Moritz; Asmus, Harald

    2012-08-01

    Species composition, abundance, feeding relationships and guild structure of the fish assemblage in the Sylt-Rømø bight, a tidal basin in the northern Wadden Sea, were investigated to show seasonal differences and the importance of functional groups in this area. The tidal flats and in shallow subtidal areas were sampled using a beach seine and a bottom trawl net was used for deeper subtidal areas and tidal gullies. Species richness of fish was highest in summer where 26 species were caught, while the lowest richness was recorded in winter (17 species). Clear differences in species richness and abundance were found between shallow areas and deeper parts of the bight. Clupea harengus and Ammodytes tobianus were the most abundant species in deeper areas, while Pomatoschistus microps and Pomatoschistus minutus dominated shallower waters. Gut contents of 27 fish species were identified and the guild structure analyzed by UPGMA clustering of niche overlaps. Calanoid copepods (19.9%), Crangon crangon (18.2%) and mysid shrimps (8.4%) were the most abundant prey items of all fish species combined. Seven feeding guilds were present in the fall and winter, and eight and six in spring and summer, respectively. Fish feeding on calanoid copepods and C. crangon were present year round, whereas the occurrence of other guilds varied between seasons. Species composition of prey changed through seasons and, for some fish species, even the feeding mode itself varied with season. Most noticeable, 11 fish species changed guilds between seasons. We found a convergence in summer towards abundant prey items, whereas in winter diet overlap was lower. This is the first investigation of guild structure of almost all fish species present in a Wadden Sea area, and shows that consideration of seasonal differences is essential when determining feeding relationships of fish in temperate areas.

  15. Is abundance a species attribute? An example with haematophagous ectoparasites.

    PubMed

    Krasnov, Boris R; Shenbrot, Georgy I; Khokhlova, Irina S; Poulin, Robert

    2006-11-01

    Population density is a fundamental property of a species and yet it varies among populations of the same species. The variation comes from the interplay between intrinsic features of a species that tend to produce repeatable density values across all populations of the same species and extrinsic environmental factors that differ among localities and thus tend to produce spatial variation in density. Is inter-population variation in density too large for density to be considered a true species character? We addressed this question using data on abundance (number of parasites per individual host, i.e. equivalent to density) of fleas ectoparasitic on small mammals. The data included samples of 548 flea populations, representing 145 flea species and obtained from 48 different geographical regions. Abundances of the same flea species on the same host species, but in different regions, were more similar to each other than expected by chance, and varied significantly among flea species, with 46% of the variation among samples accounted by differences between flea species. Thus, estimates of abundance are repeatable within the same flea species. The same repeatability was also observed, but to a lesser extent, across flea genera, tribes and subfamilies. Independently of the identity of the flea species, abundance values recorded on the same host species, or in the same geographical region, also showed significant statistical repeatability, though not nearly as strong as that associated with abundance values from the same flea species. There were also no strong indications that regional differences in abiotic variables were an important determinant of variation in abundance of a given flea species on a given host species. Abundance thus appears to be a true species trait in fleas, although it varies somewhat within bounds set by species-specific life history traits. PMID:16896773

  16. Geographical Range and Local Abundance of Tree Species in China

    PubMed Central

    Ren, Haibao; Condit, Richard; Chen, Bin; Mi, Xiangcheng; Cao, Min; Ye, Wanhui; Hao, Zhanqing; Ma, Keping

    2013-01-01

    Most studies on the geographical distribution of species have utilized a few well-known taxa in Europe and North America, with little research in China and its wide range of climate and forest types. We assembled large datasets to quantify the geographic ranges of tree species in China and to test several biogeographic hypotheses: 1) whether locally abundant species tend to be geographically widespread; 2) whether species are more abundant towards their range-centers; and 3) how abundances are correlated between sites. Local abundances of 651 species were derived from four tree plots of 20–25 ha where all individuals ≥1 cm in stem diameter were mapped and identified taxonomically. Range sizes of these species across China were then estimated from over 460,000 geo-referenced records; a Bayesian approach was used, allowing careful measures of error of each range estimate. The log-transformed range sizes had a bell-shaped distribution with a median of 703,000 km2, and >90% of 651 species had ranges >105 km2. There was no relationship between local abundance and range size, and no evidence for species being more abundant towards their range-centers. Finally, species’ abundances were positively correlated between sites. The widespread nature of most tree species in China suggests few are vulnerable to global extinction, and there is no indication of the double-peril that would result if rare species also had narrow ranges. PMID:24130772

  17. Shearwaters as ecosystem indicators: Towards fishery-independent metrics of fish abundance in the California Current

    NASA Astrophysics Data System (ADS)

    Lyday, Shannon E.; Ballance, Lisa T.; Field, David B.; David Hyrenbach, K.

    2015-06-01

    Shearwaters are ideal for monitoring ocean conditions in the California Current because these predators are abundant, conspicuous, and responsive to oceanographic variability. Herein we evaluated black-vented (Puffinus opisthomelas), Buller's (P. bulleri), flesh-footed (P. carneipes), pink-footed (P. creatopus), short-tailed (P. tenuirostris), and sooty (P. griseus) shearwaters as fishery-independent indicators of predatory or prey fish availability. We analyzed four years (1996, 2001, 2005, 2008) of monthly (August-November) National Oceanic and Atmospheric Administration seabird surveys, and United States Geological Survey Pacific Coast Fisheries Database catch, from the California coast to 200 nm offshore. An ordination of shearwater abundance and fish catch revealed that the shearwaters and 11 fish/squid species were significantly correlated with one or more of three principal components, which explained 86% of the variation and revealed distinct species assemblages. We evaluated multiple linear regression models for 19 fisheries using five shearwater metrics: density, aggregation, and behavior (traveling, stationary, feeding), three oceanographic indices, and latitude. Eight of these models had a shearwater metric as the primary predictor. In particular, feeding black-vented shearwater abundance explained 75% of dolphinfish (Coryphaena hippurus) longline catch. This research illustrates the utility of shearwaters as ecosystem indicators, with direct application for predicting fishery catch of commercial importance.

  18. Model reduction for stochastic chemical systems with abundant species.

    PubMed

    Smith, Stephen; Cianci, Claudia; Grima, Ramon

    2015-12-01

    Biochemical processes typically involve many chemical species, some in abundance and some in low molecule numbers. We first identify the rate constant limits under which the concentrations of a given set of species will tend to infinity (the abundant species) while the concentrations of all other species remains constant (the non-abundant species). Subsequently, we prove that, in this limit, the fluctuations in the molecule numbers of non-abundant species are accurately described by a hybrid stochastic description consisting of a chemical master equation coupled to deterministic rate equations. This is a reduced description when compared to the conventional chemical master equation which describes the fluctuations in both abundant and non-abundant species. We show that the reduced master equation can be solved exactly for a number of biochemical networks involving gene expression and enzyme catalysis, whose conventional chemical master equation description is analytically impenetrable. We use the linear noise approximation to obtain approximate expressions for the difference between the variance of fluctuations in the non-abundant species as predicted by the hybrid approach and by the conventional chemical master equation. Furthermore, we show that surprisingly, irrespective of any separation in the mean molecule numbers of various species, the conventional and hybrid master equations exactly agree for a class of chemical systems. PMID:26646867

  19. Model reduction for stochastic chemical systems with abundant species

    NASA Astrophysics Data System (ADS)

    Smith, Stephen; Cianci, Claudia; Grima, Ramon

    2015-12-01

    Biochemical processes typically involve many chemical species, some in abundance and some in low molecule numbers. We first identify the rate constant limits under which the concentrations of a given set of species will tend to infinity (the abundant species) while the concentrations of all other species remains constant (the non-abundant species). Subsequently, we prove that, in this limit, the fluctuations in the molecule numbers of non-abundant species are accurately described by a hybrid stochastic description consisting of a chemical master equation coupled to deterministic rate equations. This is a reduced description when compared to the conventional chemical master equation which describes the fluctuations in both abundant and non-abundant species. We show that the reduced master equation can be solved exactly for a number of biochemical networks involving gene expression and enzyme catalysis, whose conventional chemical master equation description is analytically impenetrable. We use the linear noise approximation to obtain approximate expressions for the difference between the variance of fluctuations in the non-abundant species as predicted by the hybrid approach and by the conventional chemical master equation. Furthermore, we show that surprisingly, irrespective of any separation in the mean molecule numbers of various species, the conventional and hybrid master equations exactly agree for a class of chemical systems.

  20. Model reduction for stochastic chemical systems with abundant species

    SciTech Connect

    Smith, Stephen; Cianci, Claudia; Grima, Ramon

    2015-12-07

    Biochemical processes typically involve many chemical species, some in abundance and some in low molecule numbers. We first identify the rate constant limits under which the concentrations of a given set of species will tend to infinity (the abundant species) while the concentrations of all other species remains constant (the non-abundant species). Subsequently, we prove that, in this limit, the fluctuations in the molecule numbers of non-abundant species are accurately described by a hybrid stochastic description consisting of a chemical master equation coupled to deterministic rate equations. This is a reduced description when compared to the conventional chemical master equation which describes the fluctuations in both abundant and non-abundant species. We show that the reduced master equation can be solved exactly for a number of biochemical networks involving gene expression and enzyme catalysis, whose conventional chemical master equation description is analytically impenetrable. We use the linear noise approximation to obtain approximate expressions for the difference between the variance of fluctuations in the non-abundant species as predicted by the hybrid approach and by the conventional chemical master equation. Furthermore, we show that surprisingly, irrespective of any separation in the mean molecule numbers of various species, the conventional and hybrid master equations exactly agree for a class of chemical systems.

  1. Ecological niche structure and rangewide abundance patterns of species

    PubMed Central

    Martínez-Meyer, Enrique; Díaz-Porras, Daniel; Peterson, A. Townsend; Yáñez-Arenas, Carlos

    2013-01-01

    Spatial abundance patterns across species' ranges have attracted intense attention in macroecology and biogeography. One key hypothesis has been that abundance declines with geographical distance from the range centre, but tests of this idea have shown that the effect may occur indeed only in a minority of cases. We explore an alternative hypothesis: that species' abundances decline with distance from the centroid of the species' habitable conditions in environmental space (the ecological niche). We demonstrate consistent negative abundance–ecological distance relationships across all 11 species analysed (turtles to wolves), and that relationships in environmental space are consistently stronger than relationships in geographical space. PMID:23134784

  2. Why abundant tropical tree species are phylogenetically old.

    PubMed

    Wang, Shaopeng; Chen, Anping; Fang, Jingyun; Pacala, Stephen W

    2013-10-01

    Neutral models of species diversity predict patterns of abundance for communities in which all individuals are ecologically equivalent. These models were originally developed for Panamanian trees and successfully reproduce observed distributions of abundance. Neutral models also make macroevolutionary predictions that have rarely been evaluated or tested. Here we show that neutral models predict a humped or flat relationship between species age and population size. In contrast, ages and abundances of tree species in the Panamanian Canal watershed are found to be positively correlated, which falsifies the models. Speciation rates vary among phylogenetic lineages and are partially heritable from mother to daughter species. Variable speciation rates in an otherwise neutral model lead to a demographic advantage for species with low speciation rate. This demographic advantage results in a positive correlation between species age and abundance, as found in the Panamanian tropical forest community. PMID:24043767

  3. Analysis of the parasitic copepod species richness among Mediterranean fish

    NASA Astrophysics Data System (ADS)

    Raibaut, André; Combes, Claude; Benoit, Françoise

    1998-06-01

    The Mediterranean ichthyofauna is composed of 652 species belonging to 405 genera and 117 families. Among these, 182 were studied for their parasitic copepods. The analysis of all the works conducted on these crustacea yielded 226 species distributed in 88 genera and 20 families. For each fish species we have established a file providing the species name of the fish, its family, its geographical distribution within the Mediterranean and some of its bio-ecological characteristics. Within each file, all the parasitic copepod species reported on each host species were listed. This allowed to know the species richness (SR) of these hosts. We thus produced 182 files within which 226 copepod species are distributed. A program was created under the Hypercard software, in order to analyse our data. Two parameters were studied. The first one is the mean species richness (MSR), which corresponds to the mean of the different SR found on the different host species. The second is the parasite-host ratio (P/H), which is the ratio of the number of copepod species by the number of host species. These parameters are calculated by our program for all the 182 species of Mediterranean fishes retained in our investigation, on the first hand, and, on the second hand, for one particular group of fish species. We used the following variables to investigate their correlations with copepod species richness: taxonomy—fish families, genera and species; biometry—maximal size of the adult fish; eco-ethology—mode of life (benthic, pelagic or nectonic), displacements (sedentary, migratory with environmental change, or migratory without environmental change), behaviour (solitary or gregarious). Other variables (colour, food, reproduction, abundance, distribution area) were also analysed but did not reveal any clear correlation. Providing that our study does not rely on quantitative (prevalence, intensity) but qualitative basis our aim was only to reveal some tendencies. These tendencies are

  4. Fish passage and abundance around grade control structures on incised streams

    USGS Publications Warehouse

    Thomas, J.T.; Papanicolaou, A.N.; Pierce, C.L.; Dermisis, D.C.; Litvan, M.E.; Larson, C.J.

    2009-01-01

    This paper summarizes research from separate studies of fish passage over weirs (Larson et al., 2004; Litvan, 2006; Litvan, et al., 2008a-c) and weir hydraulics (Papanicolaou and Dermisis, 2006; Papanicolaou and Dermisis, in press). Channel incision in the deep loess region of western Iowa has caused decreased biodiversity because streams have high sediment loads, altered flow regimes, lost habitat, and lost lateral connectivity with their former floodplains. In-stream grade control structures (GCS) are built to prevent further erosion, protect infrastructure, and reduce sediment loads. However, GCS can have a detrimental impact on fisheries abundance and migration, biodiversity, and longitudinal connectivity. Fish mark-recapture studies were performed on stretches of streams with and without GCS. GCS with vertical or 1:4 (rise/run) downstream slopes did not allow fish migration, but GCS with slopes ??? 1:15 did. GCS sites were characterized by greater proportions of pool habitat, maximum depths, fish biomass, slightly higher index of biotic integrity (IBI) scores, and greater macroinvertebrate abundance and diversity than non-GCS sites. After modification of three GCS, IBI scores increased and fish species exhibiting truncated distributions before were found throughout the study area. Another study examined the hydraulic performance of GCS to facilitate unimpeded fish passage by determining the mean and turbulent flow characteristics in the vicinity of the GCS via detailed, non-intrusive field tests. Mean flow depth (Y) and velocity (V) atop the GCS were critical for evaluating GCS performance. Turbulent flow measurements illustrated that certain GCS designs cause sudden constrictions which form eddies large enough to disorient fish. GCS with slopes ??? 1:15 best met the minimum requirements to allow catfish passage of a flow depth of ??? 0.31 m and a mean flow velocity of ??? 1.22 m/s. ?? 2009 ASCE.

  5. Estimating species occurrence, abundance, and detection probability using zero-inflated distributions

    USGS Publications Warehouse

    Wenger, S.J.; Freeman, Mary C.

    2008-01-01

    Researchers have developed methods to account for imperfect detection of species with either occupancy (presence-absence) or count data using replicated sampling. We show how these approaches can be combined to simultaneously estimate occurrence, abundance, and detection probability by specifying a zero-inflated distribution for abundance. This approach may be particularly appropriate when patterns of occurrence and abundance arise from distinct processes operating at differing spatial or temporal scales. We apply the model to two data sets: (1) previously published data for a species of duck, Anas platyrhynchos, and (2) data for a stream fish species, Etheostoma scotti. We show that in these cases, an incomplete-detection zero-inflated modeling approach yields a superior fit to the data than other models. We propose that zero-inflated abundance models accounting for incomplete detection be considered when replicate count data are available.

  6. Multiple peaks of species abundance distributions induced by sparse interactions.

    PubMed

    Obuchi, Tomoyuki; Kabashima, Yoshiyuki; Tokita, Kei

    2016-08-01

    We investigate the replicator dynamics with "sparse" symmetric interactions which represent specialist-specialist interactions in ecological communities. By considering a large self-interaction u, we conduct a perturbative expansion which manifests that the nature of the interactions has a direct impact on the species abundance distribution. The central results are all species coexistence in a realistic range of the model parameters and that a certain discrete nature of the interactions induces multiple peaks in the species abundance distribution, providing the possibility of theoretically explaining multiple peaks observed in various field studies. To get more quantitative information, we also construct a non-perturbative theory which becomes exact on tree-like networks if all the species coexist, providing exact critical values of u below which extinct species emerge. Numerical simulations in various different situations are conducted and they clarify the robustness of the presented mechanism of all species coexistence and multiple peaks in the species abundance distributions. PMID:27627322

  7. Percolation Theory for the Distribution and Abundance of Species

    NASA Astrophysics Data System (ADS)

    He, Fangliang; Hubbell, Stephen P.

    2003-11-01

    We develop and test new models that unify the mathematical relationships among the abundance of a species, the spatial dispersion of the species, the number of patches occupied by the species, the edge length of the occupied patches, and the scale on which the distribution of species is mapped. The models predict that species distributions will exhibit percolation critical thresholds, i.e., critical population abundances at which the fragmented patches (as measured by the number of patches and edge length) start to coalesce to form large patches.

  8. NATIVE FRESHWATER FISH AND MUSSEL SPECIES RICHNESS

    EPA Science Inventory

    These data represent predicted current distributions of all native freshwater fish and freshwater mussels in the Middle-Atlantic region. The data are available for both 8-digit HUCs and EMAP hexagons and represent total species counts for each spatial unit.

  9. Conditions for coexistence of freshwater mussel species via partitioning of fish host resources

    USGS Publications Warehouse

    Rashleigh, B.; DeAngelis, D.L.

    2007-01-01

    Riverine freshwater mussel species can be found in highly diverse communities where many similar species coexist. Mussel species potentially compete for food and space as adults, and for fish host resources during the larval (glochidial) stage. Resource partitioning at the larval stage may promote coexistence. A model of resource utilization was developed for two mussel species and analyzed to determine conditions for coexistence. Mussel species were predicted to coexist when they differed in terms of their success in contacting different fish host species; very similar strategies offered limited possibilities for coexistence. Differences in the mussel species' maximum infestation loads on the fish hosts that coincided with differences in their fish host contact success promoted coexistence. Mussel species with a given set of trade-offs in fish host use were predicted to coexist only for a subset of relative fish host abundances, so a shift in relative fish host abundances could result in the loss of a mussel species. An understanding of the conditions for freshwater mussel species coexistence can help explain high mussel diversity in rivers and guide ongoing conservation activities. ?? 2006 Elsevier B.V. All rights reserved.

  10. Modelling occurrence and abundance of species when detection is imperfect

    USGS Publications Warehouse

    Royle, J. Andrew; Nichols, J.D.; Kery, M.

    2005-01-01

    Relationships between species abundance and occupancy are of considerable interest in metapopulation biology and in macroecology. Such relationships may be described concisely using probability models that characterize variation in abundance of a species. However, estimation of the parameters of these models in most ecological problems is impaired by imperfect detection. When organisms are detected imperfectly, observed counts are biased estimates of true abundance, and this induces bias in stated occupancy or occurrence probability. In this paper we consider a class of models that enable estimation of abundance/occupancy relationships from counts of organisms that result from surveys in which detection is imperfect. Under such models, parameter estimation and inference are based on conventional likelihood methods. We provide an application of these models to geographically extensive breeding bird survey data in which alternative models of abundance are considered that include factors that influence variation in abundance and detectability. Using these models, we produce estimates of abundance and occupancy maps that honor important sources of spatial variation in avian abundance and provide clearly interpretable characterizations of abundance and occupancy adjusted for imperfect detection.

  11. How well can we predict forage species occurrence and abundance?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As part of a larger effort focused on forage species production and management, we have been developing a statistical modeling approach to predict the probability of species occurrence and the abundance for Orchard Grass over the Northeast region of the United States using two selected statistical m...

  12. Predicting fish species distribution in estuaries: Influence of species' ecology in model accuracy

    NASA Astrophysics Data System (ADS)

    França, Susana; Cabral, Henrique N.

    2016-10-01

    Current threats to biodiversity, combined with limited data availability, have made for species distribution models (SDMs) to be increasingly used due to their ability to predict species' potential distribution, by relating species occurrence with environmental estimates. Often used in ecology, conservation biology and environmental management, SDMs have been informing conservation strategies, and thus it is becoming crucial to understand how trustworthy their predictions are. Uncertainty in model predictions is expected, but knowing the origin of prediction errors may help reducing it. Indeed, uncertainty may be related not only with data quality and the modelling algorithm used, but also with species ecological characteristics. To investigate whether the performance of SDM's may vary with species' ecological characteristics, distribution models for 21 fish species occurring in estuaries from the Portuguese coast were examined. These models were built at two distinct spatial resolutions and seven environmental explanatory variables were used as predictors. SDMs' accuracy was assessed with the area under the curve (AUC) of receiver operating characteristics (ROC) plots, sensitivity and specificity. Relationships between each measure of accuracy and species ecological characteristics were then examined. SDMs of the fish species presented small differences between the considered scales, and predictors as latitude, temperature and salinity were often selected at both scales. Measures of model accuracy presented differences between species and scales, but generally higher accuracy was obtained at smaller spatial scales. Among the ecological traits tested, species feeding mode and estuarine use functional groups were the most influential on the performance of distribution models. Habitat tolerance (number of habitat types frequented), species abundance, body size and spawning period also showed some effect. This analyses will contribute to distinguish, based on species

  13. Effect of disjunct size distributions on foraminiferal species abundance determinations

    SciTech Connect

    Martin, R.E.; Liddell, W.D.

    1988-02-01

    Studies of foraminiferal distribution and abundance have typically employed a procedure (standard method) that entails counting approximately 300 specimens from a size range greater than some specified minimum (commonly 63 or 125 ..mu..m). This method fails to take into account that foraminifera may be found only within certain size fractions, either because of species specific size ranges or taphonomic processes (sorting, transport, abrasion). Use of a modified counting procedure (sieve method) takes into account foraminiferal size distributions. The sieve method uses counts of up to 300 specimens in each sand-size fraction (0.125-0.25, 0.25-0.5, 0.5-1, 1-2 mm) of each sample. Counts are then totaled for each sample (up to 1200 specimens per site) and used in determination of species abundances for each site. The sieve method has been of considerable utility in recognition of a foraminiferal bathymetric zonation preserved in sediment assemblages from fringing reef environments at Discovery Bay, north Jamaica. Well-documented reef zones (based on corals and physiography) are clearly defined in Q-mode cluster analysis (UPGMA) of species abundances determined using the sieve method. In contrast, individual fore reef zones are not recognized in cluster analysis of foraminiferal species abundances based on the standard method, nor by cluster analysis of species abundances within individual size fractions.

  14. INFLUENCE OF TURBIDITY ON FISH ABUNDANCE IN WESTERN LAKE SUPERIOR

    EPA Science Inventory

    This research project was developed to improve understanding of the influence of turbidity on fish populations and the mechanism through which its effects are induced. Field and laboratory studies emphasized measurement of behavioral response of fish and resulting changes in fish...

  15. Abundance, diversity, and activity of microbial assemblages associated with coral reef fish guts and feces.

    PubMed

    Smriga, Steven; Sandin, Stuart A; Azam, Farooq

    2010-07-01

    Feces and distal gut contents were collected from three coral reef fish species. Bacteria cell abundances, as determined via epifluorescence microscopy, ranged two orders of magnitude among the fishes. Mass-specific and apparent cell-specific hydrolytic enzyme activities in feces from Chlorurus sordidus were very high, suggesting that endogenous fish enzymes were egested into feces. Denaturing gradient gel electrophoresis profiles of 16S rRNA genes were more similar among multiple individuals of the surgeonfish Acanthurus nigricans than among individuals of the parrotfish C. sordidus or the snapper Lutjanus bohar. Analyses of feces-derived 16S rRNA gene clones revealed that at least five bacterial phyla were present in A. nigricans and that Vibrionaceae comprised 10% of the clones. Meanwhile, C. sordidus contained at least five phyla and L. bohar three, but Vibrionaceae comprised 71% and 76% of the clones, respectively. Many sequences clustered phylogenetically to cultured Vibrio spp. and Photobacterium spp. including Vibrio ponticus and Photobacterium damselae. Other Vibrionaceae-like sequences comprised a distinct phylogenetic group that may represent the presence of 'feces-specific' bacteria. The observed differences among fishes may reflect native gut microbiota and/or bacterial assemblages associated with ingested prey. PMID:20455942

  16. Relating species abundance distributions to species-area curves in two Mediterranean-type shrublands

    USGS Publications Warehouse

    Keeley, J.E.

    2003-01-01

    Based on both theoretical and empirical studies there is evidence that different species abundance distributions underlie different species-area relationships. Here I show that Australian and Californian shrubland communities (at the scale from 1 to 1000 m2) exhibit different species-area relationships and different species abundance patterns. The species-area relationship in Australian heathlands best fits an exponential model and species abundance (based on both density and cover) follows a narrow log normal distribution. In contrast, the species-area relationship in Californian shrublands is best fit with the power model and, although species abundance appears to fit a log normal distribution, the distribution is much broader than in Australian heathlands. I hypothesize that the primary driver of these differences is the abundance of small-stature annual species in California and the lack of annuals in Australian heathlands. Species-area is best fit by an exponential model in Australian heathlands because the bulk of the species are common and thus the species-area curves initially rise rapidly between 1 and 100 m2. Annuals in Californian shrublands generate very broad species abundance distributions with many uncommon or rare species. The power function is a better model in these communities because richness increases slowly from 1 to 100 m2 but more rapidly between 100 and 1000 m2 due to the abundance of rare or uncommon species that are more likely to be encountered at coarser spatial scales. The implications of this study are that both the exponential and power function models are legitimate representations of species-area relationships in different plant communities. Also, structural differences in community organization, arising from different species abundance distributions, may lead to different species-area curves, and this may be tied to patterns of life form distribution.

  17. Direct evidence that density-dependent regulation underpins the temporal stability of abundant species in a diverse animal community

    PubMed Central

    Henderson, Peter A.; Magurran, Anne E.

    2014-01-01

    To understand how ecosystems are structured and stabilized, and to identify when communities are at risk of damage or collapse, we need to know how the abundances of the taxa in the entire assemblage vary over ecologically meaningful timescales. Here, we present an analysis of species temporal variability within a single large vertebrate community. Using an exceptionally complete 33-year monthly time series following the dynamics of 81 species of fishes, we show that the most abundant species are least variable in terms of temporal biomass, because they are under density-dependent (negative feedback) regulation. At the other extreme, a relatively large number of low abundance transient species exhibit the greatest population variability. The high stability of the consistently common high abundance species—a result of density-dependence—is reflected in the observation that they consistently represent over 98% of total fish biomass. This leads to steady ecosystem nutrient and energy flux irrespective of the changes in species number and abundance among the large number of low abundance transient species. While the density-dependence of the core species ensures stability under the existing environmental regime, the pool of transient species may support long-term stability by replacing core species should environmental conditions change. PMID:25100702

  18. Integrating abundance and functional traits reveals new global hotspots of fish diversity.

    PubMed

    Stuart-Smith, Rick D; Bates, Amanda E; Lefcheck, Jonathan S; Duffy, J Emmett; Baker, Susan C; Thomson, Russell J; Stuart-Smith, Jemina F; Hill, Nicole A; Kininmonth, Stuart J; Airoldi, Laura; Becerro, Mikel A; Campbell, Stuart J; Dawson, Terence P; Navarrete, Sergio A; Soler, German A; Strain, Elisabeth M A; Willis, Trevor J; Edgar, Graham J

    2013-09-26

    Species richness has dominated our view of global biodiversity patterns for centuries. The dominance of this paradigm is reflected in the focus by ecologists and conservation managers on richness and associated occurrence-based measures for understanding drivers of broad-scale diversity patterns and as a biological basis for management. However, this is changing rapidly, as it is now recognized that not only the number of species but the species present, their phenotypes and the number of individuals of each species are critical in determining the nature and strength of the relationships between species diversity and a range of ecological functions (such as biomass production and nutrient cycling). Integrating these measures should provide a more relevant representation of global biodiversity patterns in terms of ecological functions than that provided by simple species counts. Here we provide comparisons of a traditional global biodiversity distribution measure based on richness with metrics that incorporate species abundances and functional traits. We use data from standardized quantitative surveys of 2,473 marine reef fish species at 1,844 sites, spanning 133 degrees of latitude from all ocean basins, to identify new diversity hotspots in some temperate regions and the tropical eastern Pacific Ocean. These relate to high diversity of functional traits amongst individuals in the community (calculated using Rao's Q), and differ from previously reported patterns in functional diversity and richness for terrestrial animals, which emphasize species-rich tropical regions only. There is a global trend for greater evenness in the number of individuals of each species, across the reef fish species observed at sites ('community evenness'), at higher latitudes. This contributes to the distribution of functional diversity hotspots and contrasts with well-known latitudinal gradients in richness. Our findings suggest that the contribution of species diversity to a range of

  19. Distance from a fishing community explains fish abundance in a no-take zone with weak compliance.

    PubMed

    Advani, Sahir; Rix, Laura N; Aherne, Danielle M; Alwany, Magdy A; Bailey, David M

    2015-01-01

    There are numerous examples of no-take marine reserves effectively conserving fish stocks within their boundaries. However, no-take reserves can be rendered ineffective and turned into 'paper parks' through poor compliance and weak enforcement of reserve regulations. Long-term monitoring is thus essential to assess the effectiveness of marine reserves in meeting conservation and management objectives. This study documents the present state of the 15-year old no-take zone (NTZ) of South El Ghargana within the Nabq Managed Resource Protected Area, South Sinai, Egyptian Red Sea. Previous studies credited willing compliance by the local fishing community for the increased abundances of targeted fish within the designated NTZ boundaries compared to adjacent fished or take-zones. We compared benthic habitat and fish abundance within the NTZ and the adjacent take sites open to fishing, but found no significant effect of the reserve. Instead, the strongest evidence was for a simple negative relationship between fishing pressure and distance from the closest fishing village. The abundance of targeted piscivorous fish increased significantly with increasing distance from the village, while herbivorous fish showed the opposite trend. This gradient was supported by a corresponding negative correlation between the amount of discarded fishing gear observed on the reef and increasing distance from the village. Discarded fishing gear within the NTZ suggested decreased compliance with the no-take regulations. Our findings indicate that due to non-compliance the no-take reserve is no longer functioning effectively, despite its apparent initial successes and instead a gradient of fishing pressure exists with distance from the nearest fishing community. PMID:25950815

  20. Distance from a Fishing Community Explains Fish Abundance in a No-Take Zone with Weak Compliance

    PubMed Central

    Alwany, Magdy A.; Bailey, David M.

    2015-01-01

    There are numerous examples of no-take marine reserves effectively conserving fish stocks within their boundaries. However, no-take reserves can be rendered ineffective and turned into ‘paper parks’ through poor compliance and weak enforcement of reserve regulations. Long-term monitoring is thus essential to assess the effectiveness of marine reserves in meeting conservation and management objectives. This study documents the present state of the 15-year old no-take zone (NTZ) of South El Ghargana within the Nabq Managed Resource Protected Area, South Sinai, Egyptian Red Sea. Previous studies credited willing compliance by the local fishing community for the increased abundances of targeted fish within the designated NTZ boundaries compared to adjacent fished or take-zones. We compared benthic habitat and fish abundance within the NTZ and the adjacent take sites open to fishing, but found no significant effect of the reserve. Instead, the strongest evidence was for a simple negative relationship between fishing pressure and distance from the closest fishing village. The abundance of targeted piscivorous fish increased significantly with increasing distance from the village, while herbivorous fish showed the opposite trend. This gradient was supported by a corresponding negative correlation between the amount of discarded fishing gear observed on the reef and increasing distance from the village. Discarded fishing gear within the NTZ suggested decreased compliance with the no-take regulations. Our findings indicate that due to non-compliance the no-take reserve is no longer functioning effectively, despite its apparent initial successes and instead a gradient of fishing pressure exists with distance from the nearest fishing community. PMID:25950815

  1. ABC transporters in fish species: a review

    PubMed Central

    Ferreira, Marta; Costa, Joana; Reis-Henriques, Maria A.

    2014-01-01

    ATP-binding cassette (ABC) proteins were first recognized for their role in multidrug resistance (MDR) in chemotherapeutic treatments, which is a major impediment for the successful treatment of many forms of malignant tumors in humans. These proteins, highly conserved throughout vertebrate species, were later related to cellular detoxification and accounted as responsible for protecting aquatic organisms from xenobiotic insults in the so-called multixenobiotic resistance mechanism (MXR). In recent years, research on these proteins in aquatic species has highlighted their importance in the detoxification mechanisms in fish thus it is necessary to continue these studies. Several transporters have been pointed out as relevant in the ecotoxicological context associated to the transport of xenobiotics, such as P-glycoproteins (Pgps), multidrug-resistance-associated proteins (MRPs 1-5) and breast cancer resistance associated protein (BCRP). In mammals, several nuclear receptors have been identified as mediators of phase I and II metabolizing enzymes and ABC transporters. In aquatic species, knowledge on co-regulation of the detoxification mechanism is scarce and needs to be addressed. The interaction of emergent contaminants that can act as chemosensitizers, with ABC transporters in aquatic organisms can compromise detoxification processes and have population effects and should be studied in more detail. This review intends to summarize the recent advances in research on MXR mechanisms in fish species, focusing in (1) regulation and functioning of ABC proteins; (2) cooperation with phase I and II biotransformation enzymes; and (3) ecotoxicological relevance and information on emergent pollutants with ability to modulate ABC transporters expression and activity. Several lines of evidence are clearly suggesting the important role of these transporters in detoxification mechanisms and must be further investigated in fish to underlay the mechanism to consider their use as

  2. Abundance of common species, not species richness, drives delivery of a real-world ecosystem service.

    PubMed

    Winfree, Rachael; Fox, Jeremy W; Williams, Neal M; Reilly, James R; Cariveau, Daniel P

    2015-07-01

    Biodiversity-ecosystem functioning experiments have established that species richness and composition are both important determinants of ecosystem function in an experimental context. Determining whether this result holds for real-world ecosystem services has remained elusive, however, largely due to the lack of analytical methods appropriate for large-scale, associational data. Here, we use a novel analytical approach, the Price equation, to partition the contribution to ecosystem services made by species richness, composition and abundance in four large-scale data sets on crop pollination by native bees. We found that abundance fluctuations of dominant species drove ecosystem service delivery, whereas richness changes were relatively unimportant because they primarily involved rare species that contributed little to function. Thus, the mechanism behind our results was the skewed species-abundance distribution. Our finding that a few common species, not species richness, drive ecosystem service delivery could have broad generality given the ubiquity of skewed species-abundance distributions in nature. PMID:25959973

  3. Predatory fish sounds can alter crab foraging behaviour and influence bivalve abundance

    PubMed Central

    Hughes, A. Randall; Mann, David A.; Kimbro, David L.

    2014-01-01

    The risk of predation can have large effects on ecological communities via changes in prey behaviour, morphology and reproduction. Although prey can use a variety of sensory signals to detect predation risk, relatively little is known regarding the effects of predator acoustic cues on prey foraging behaviour. Here we show that an ecologically important marine crab species can detect sound across a range of frequencies, probably in response to particle acceleration. Further, crabs suppress their resource consumption in the presence of experimental acoustic stimuli from multiple predatory fish species, and the sign and strength of this response is similar to that elicited by water-borne chemical cues. When acoustic and chemical cues were combined, consumption differed from expectations based on independent cue effects, suggesting redundancies among cue types. These results highlight that predator acoustic cues may influence prey behaviour across a range of vertebrate and invertebrate taxa, with the potential for cascading effects on resource abundance. PMID:24943367

  4. Abundance of introduced species at home predicts abundance away in herbaceous grasslands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced versus native communities, because ecological or evolutionary based shifts in popula...

  5. Targeted demersal fish species exhibit variable responses to long-term protection from fishing at the Houtman Abrolhos Islands

    NASA Astrophysics Data System (ADS)

    Bornt, Katrina R.; McLean, Dianne L.; Langlois, Tim J.; Harvey, Euan S.; Bellchambers, Lynda M.; Evans, Scott N.; Newman, Stephen J.

    2015-12-01

    Natural fluctuations in the abundance and length of targeted fish are often disrupted by acute environmental changes and anthropogenic impacts, particularly fishing pressure. Long-term assessments of targeted fish populations inside and outside areas closed to fishing are often necessary to elucidate these effects, yet few of these studies extend over long time periods. We assessed trends in the abundance and length of six targeted fish species in areas open and closed to fishing on seven occasions spanning a 9-year period (2005-2010 and 2013) at the Houtman Abrolhos Islands, Western Australia. Shallow (8-12 m) and deep (22-26 m) coral-dominated reef sites were sampled across four geographically separated island groups using baited remote underwater stereo-video (stereo-BRUV). Between 2005 and 2010, populations of Lethrinus miniatus, Lethrinus nebulosus, Plectropomus leopardus, and Chrysophrys auratus became increasingly dominated by larger individuals, potentially indicative of an ageing population. Between 2010 and 2013, however, there was a significant increase in the proportion of smaller L. miniatus, L. nebulosus, and P. leopardus in both open and closed areas, reflecting increased recruitment perhaps due to changing environmental conditions associated with a marine heat wave anomaly. This recruitment pulse was not observed for the other species in this study ( Chr. auratus, Choerodon rubescens, and Glaucosoma hebraicum). Lethrinus miniatus, L. nebulosus, Chr. auratus, and P. leopardus were larger in closed areas relative to open areas; however, they were not more abundant. These complex responses to protection also varied across sampling years for certain species (e.g., P. leopardus). Monitoring changes over the long-term in areas open and closed to fishing provides a sound basis for separating environmental variability from that associated with fishing mortality, which is crucial for optimising fisheries management.

  6. Effectiveness of mosquito traps in measuring species abundance and composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mosquito species abundance and composition estimates provided by trapping devices are commonly used to guide control efforts, but knowledge of trap biases is necessary for accurately interpreting results. We compared the Mosquito Magnet – Pro, the Mosquito Magnet – X and the CDC Miniature Light Trap...

  7. Capitalizing on opportunistic data for monitoring relative abundances of species.

    PubMed

    Giraud, Christophe; Calenge, Clément; Coron, Camille; Julliard, Romain

    2016-06-01

    With the internet, a massive amount of information on species abundance can be collected by citizen science programs. However, these data are often difficult to use directly in statistical inference, as their collection is generally opportunistic, and the distribution of the sampling effort is often not known. In this article, we develop a general statistical framework to combine such "opportunistic data" with data collected using schemes characterized by a known sampling effort. Under some structural assumptions regarding the sampling effort and detectability, our approach makes it possible to estimate the relative abundance of several species in different sites. It can be implemented through a simple generalized linear model. We illustrate the framework with typical bird datasets from the Aquitaine region in south-western France. We show that, under some assumptions, our approach provides estimates that are more precise than the ones obtained from the dataset with a known sampling effort alone. When the opportunistic data are abundant, the gain in precision may be considerable, especially for rare species. We also show that estimates can be obtained even for species recorded only in the opportunistic scheme. Opportunistic data combined with a relatively small amount of data collected with a known effort may thus provide access to accurate and precise estimates of quantitative changes in relative abundance over space and/or time. PMID:26496390

  8. Measuring β-diversity with species abundance data.

    PubMed

    Barwell, Louise J; Isaac, Nick J B; Kunin, William E

    2015-07-01

    In 2003, 24 presence-absence β-diversity metrics were reviewed and a number of trade-offs and redundancies identified. We present a parallel investigation into the performance of abundance-based metrics of β-diversity. β-diversity is a multi-faceted concept, central to spatial ecology. There are multiple metrics available to quantify it: the choice of metric is an important decision. We test 16 conceptual properties and two sampling properties of a β-diversity metric: metrics should be 1) independent of α-diversity and 2) cumulative along a gradient of species turnover. Similarity should be 3) probabilistic when assemblages are independently and identically distributed. Metrics should have 4) a minimum of zero and increase monotonically with the degree of 5) species turnover, 6) decoupling of species ranks and 7) evenness differences. However, complete species turnover should always generate greater values of β than extreme 8) rank shifts or 9) evenness differences. Metrics should 10) have a fixed upper limit, 11) symmetry (βA,B  = βB,A ), 12) double-zero asymmetry for double absences and double presences and 13) not decrease in a series of nested assemblages. Additionally, metrics should be independent of 14) species replication 15) the units of abundance and 16) differences in total abundance between sampling units. When samples are used to infer β-diversity, metrics should be 1) independent of sample sizes and 2) independent of unequal sample sizes. We test 29 metrics for these properties and five 'personality' properties. Thirteen metrics were outperformed or equalled across all conceptual and sampling properties. Differences in sensitivity to species' abundance lead to a performance trade-off between sample size bias and the ability to detect turnover among rare species. In general, abundance-based metrics are substantially less biased in the face of undersampling, although the presence-absence metric, βsim , performed well overall. Only

  9. Patterns of relative species abundance in rainforests and coral reefs.

    PubMed

    Volkov, Igor; Banavar, Jayanth R; Hubbell, Stephen P; Maritan, Amos

    2007-11-01

    A formidable many-body problem in ecology is to understand the complex of factors controlling patterns of relative species abundance (RSA) in communities of interacting species. Unlike many problems in physics, the nature of the interactions in ecological communities is not completely known. Although most contemporary theories in ecology start with the basic premise that species interact, here we show that a theory in which all interspecific interactions are turned off leads to analytical results that are in agreement with RSA data from tropical forests and coral reefs. The assumption of non-interacting species leads to a sampling theory for the RSA that yields a simple approximation at large scales to the exact theory. Our results show that one can make significant theoretical progress in ecology by assuming that the effective interactions among species are weak in the stationary states in species-rich communities such as tropical forests and coral reefs. PMID:17972874

  10. Analytical formulae for computing dominance from species-abundance distributions.

    PubMed

    Fung, Tak; Villain, Laura; Chisholm, Ryan A

    2015-12-01

    The evenness of an ecological community affects ecosystem structure, functioning and stability, and has implications for biodiversity conservation. In uneven communities, most species are rare while a few dominant species drive ecosystem-level properties. In even communities, dominance is lower, with possibly many species playing key ecological roles. The dominance aspect of evenness can be measured as a decreasing function of the proportion of species required to make up a fixed fraction (e.g., half) of individuals in a community. Here we sought general rules about dominance in ecological communities by linking dominance mathematically to the parameters of common theoretical species-abundance distributions (SADs). We found that if a community's SAD was log-series or lognormal, then dominance was almost inevitably high, with fewer than 40% of species required to account for 90% of all individuals. Dominance for communities with an exponential SAD was lower but still typically high, with fewer than 40% of species required to account for 70% of all individuals. In contrast, communities with a gamma SAD only exhibited high dominance when the average species abundance was below a threshold of approximately 100. Furthermore, we showed that exact values of dominance were highly scale-dependent, exhibiting non-linear trends with changing average species abundance. We also applied our formulae to SADs derived from a mechanistic community model to demonstrate how dominance can increase with environmental variance. Overall, our study provides a rigorous basis for theoretical explorations of the dynamics of dominance in ecological communities, and how this affects ecosystem functioning and stability. PMID:26409166

  11. Size-Based Hydroacoustic Measures of Within-Season Fish Abundance in a Boreal Freshwater Ecosystem

    PubMed Central

    Pollom, Riley A.; Rose, George A.

    2015-01-01

    Eleven sequential size-based hydroacoustic surveys conducted with a 200 kHz split-beam transducer during the summers of 2011 and 2012 were used to quantify seasonal declines in fish abundance in a boreal reservoir in Manitoba, Canada. Fish densities were sufficiently low to enable single target resolution and tracking. Target strengths converted to log2-based size-classes indicated that smaller fish were consistently more abundant than larger fish by a factor of approximately 3 for each halving of length. For all size classes, in both years, abundance (natural log) declined linearly over the summer at rates that varied from -0.067.day-1 for the smallest fish to -0.016.day-1 for the largest (R2 = 0.24–0.97). Inter-annual comparisons of size-based abundance suggested that for larger fish (>16 cm), mean winter decline rates were an order of magnitude lower (-0.001.day-1) and overall survival higher (71%) than in the main summer fishing season (mean loss rate -0.038.day-1; survival 33%). We conclude that size-based acoustic survey methods have the potential to assess within-season fish abundance dynamics, and may prove useful in long-term monitoring of productivity and hence management of boreal aquatic ecosystems. PMID:25875467

  12. Long-term change in benthopelagic fish abundance in the abyssal northeast Pacific Ocean.

    PubMed

    Bailey, D M; Ruhl, H A; Smith, K L

    2006-03-01

    Food web structure, particularly the relative importance of bottom-up and top-down control of animal abundances, is poorly known for the Earth's largest habitats: the abyssal plains. A unique 15-yr time series of climate, productivity, particulate flux, and abundance of primary consumers (primarily echinoderms) and secondary consumers (fish) was examined to elucidate the response of trophic levels to temporal variation in one another. Towed camera sled deployments in the abyssal northeast Pacific (4100 m water depth) showed that annual mean numbers of the dominant fish genus (Coryphaenoides spp.) more than doubled over the period 1989-2004. Coryphaenoides spp. abundance was significantly correlated with total abundance of mobile epibenthic megafauna (echinoderms), with changes in fish abundance lagging behind changes in the echinoderms. Direct correlations between surface climate and fish abundances, and particulate organic carbon (POC) flux and fish abundances, were insignificant, which may be related to the varied response of the potential prey taxa to climate and POC flux. This study provides a rare opportunity to study the long-term dynamics of an unexploited marine fish population and suggests a dominant role for bottom-up control in this system. PMID:16602284

  13. Connectivity and conditional models of access and abundance of species in stream networks.

    PubMed

    Chelgren, Nathan D; Dunham, Jason B

    2015-07-01

    Barriers to passage of aquatic organisms at stream road crossings are a major cause of habitat fragmentation in stream networks. Accordingly, large investments have been made to restore passage at these crossings, but often without estimation of population-level benefits. Here, we describe a broad-scale approach to quantifying the effectiveness of passage restoration in terms interpretable at population levels, namely numbers of fish and length of stream gained through restoration, by sampling abundance in a study design that accounts for variable biogeographic species pools, variable stream and barrier configurations, and variable probabilities of capture and detectability for multiple species. We modified an existing zero-inflated negative-binomial model to estimate the probability of site access, abundance conditional on access, and capture probability of individual fish. Therein, we modeled probability of access as a function of gradient, stream road-crossing type, and downstream access by fish simultaneously with a predictive model for abundance at sites accessible to fish. Results indicated that replacement of barriers with new crossing designs intended to allow for greater movement was associated with dramatically higher probability of access for all fishes, including migratory Pacific salmon, trout, sculpin, and lamprey. Conversely, existing non-replaced crossings negatively impacted fish distributions. Assuming no downstream constraints on access, we estimated the potential length of stream restored by the program ranged between 7.33 (lamprey) and 15.28 km (small coastal cutthroat and rainbow trout). These contributions represented a fraction of the total length available upstream (187 km) of replaced crossings. When limited ranges of species were considered, the estimated contributions of culvert replacement were reduced (1.65-km range, for longnose dace to 12.31 km for small coastal cutthroat and rainbow trout). Numbers of fish contributed ranged from

  14. Phylogeny of Fish-Infecting Calyptospora species (Apicomplexa: Eimeriorina)

    EPA Science Inventory

    There are numerous species of apicomplexans that infect poikilothermic vertebrates such as fishes, and possess unique morphological features that provide insight into the evolution of this important phylum of parasites. Here the relationship of the fish-infecting Calyptospora spe...

  15. Assessing introduction risk using species' rank-abundance distributions.

    PubMed

    Chan, Farrah T; Bradie, Johanna; Briski, Elizabeta; Bailey, Sarah A; Simard, Nathalie; MacIsaac, Hugh J

    2015-01-22

    Mixed-species assemblages are often unintentionally introduced into new ecosystems. Analysing how assemblage structure varies during transport may provide insights into how introduction risk changes before propagules are released. Characterization of introduction risk is typically based on assessments of colonization pressure (CP, the number of species transported) and total propagule pressure (total PP, the total abundance of propagules released) associated with an invasion vector. Generally, invasion potential following introduction increases with greater CP or total PP. Here, we extend these assessments using rank-abundance distributions to examine how CP : total PP relationships change temporally in ballast water of ocean-going ships. Rank-abundance distributions and CP : total PP patterns varied widely between trans-Atlantic and trans-Pacific voyages, with the latter appearing to pose a much lower risk than the former. Responses also differed by taxonomic group, with invertebrates experiencing losses mainly in total PP, while diatoms and dinoflagellates sustained losses mainly in CP. In certain cases, open-ocean ballast water exchange appeared to increase introduction risk by uptake of new species or supplementation of existing ones. Our study demonstrates that rank-abundance distributions provide new insights into the utility of CP and PP in characterizing introduction risk. PMID:25473007

  16. Species richness, equitability, and abundance of ants in disturbed landscapes

    USGS Publications Warehouse

    Graham, J.H.; Krzysik, A.J.; Kovacic, D.A.; Duda, J.J.; Freeman, D.C.; Emlen, J.M.; Zak, J.C.; Long, W.R.; Wallace, M.P.; Chamberlin-Graham, C.; Nutter, J.P.; Balbach, H.E.

    2009-01-01

    Ants are used as indicators of environmental change in disturbed landscapes, often without adequate understanding of their response to disturbance. Ant communities in the southeastern United States displayed a hump-backed species richness curve against an index of landscape disturbance. Forty sites at Fort Benning, in west-central Georgia, covered a spectrum of habitat disturbance (military training and fire) in upland forest. Sites disturbed by military training had fewer trees, less canopy cover, more bare ground, and warmer, more compact soils with shallower A-horizons. We sampled ground-dwelling ants with pitfall traps, and measured 15 habitat variables related to vegetation and soil. Ant species richness was greatest with a relative disturbance of 43%, but equitability was greatest with no disturbance. Ant abundance was greatest with a relative disturbance of 85%. High species richness at intermediate disturbance was associated with greater within-site spatial heterogeneity. Species richness was also associated with intermediate values of the normalized difference vegetation index (NDVI), a correlate of net primary productivity (NPP). Available NPP (the product of NDVI and the fraction of days that soil temperature exceeded 25 ??C), however, was positively correlated with species richness, though not with ant abundance. Species richness was unrelated to soil texture, total ground cover, and fire frequency. Ant species richness and equitability are potential state indicators of the soil arthropod community. Moreover, equitability can be used to monitor ecosystem change. ?? 2008 Elsevier Ltd.

  17. Persistent disturbance by commercial navigation afters the relative abundance of channel-dwelling fishes in a large river

    USGS Publications Warehouse

    Gutreuter, S.; Vallazza, J.M.; Knights, B.C.

    2006-01-01

    We provide the first evidence for chronic effects of disturbance by commercial vessels on the spatial distribution and abundance of fishes in the channels of a large river. Most of the world's large rivers are intensively managed to satisfy increasing demands for commercial shipping, but little research has been conducted to identify and alleviate any adverse consequences of commercial navigation. We used a combination of a gradient sampling design incorporating quasicontrol areas with Akaike's information criterion (AIC)-weighted model averaging to estimate effects of disturbances by commercial vessels on fishes in the upper Mississippi River. Species density, which mainly measured species evenness, decreased with increasing disturbance frequency. The most abundant species - gizzard shad (Dorosoma cepedianum) and freshwater drum (Aplodinotus grunniens) - and the less abundant shovelnose sturgeon (Scaphirhynchus platorhynchus) and flathead catfish (Pylodictis olivaris) were seemingly unaffected by traffic disturbance. In contrast, the relative abundance of the toothed herrings (Hiodon spp.), redhorses (Moxostoma spp.), buffaloes (Ictiobus spp.), channel catfish (Ictalurus punctatus), sauger (Sander canadensis), and white bass (Morone chrysops) decreased with increasing traffic in the navigation channel. We hypothesized that the combination of alteration of hydraulic features within navigation channels and rehabilitation of secondary channels might benefit channel-dependent species. ?? 2006 NRC.

  18. Coral reef habitats mapping of Spermonde Archipelago using remote sensing compared with in situ survey of fish abundance

    NASA Astrophysics Data System (ADS)

    Sawayama, Shuhei; Komatsu, Teruhisa; Nurdin, Nurjannah

    2012-10-01

    Coral reefs worldwide are now facing so great threat due to various impacts that their monitoring is urgently required for conservation and management. To understand status of coral reef ecosystem and find out indicator fish species for health of ecosystem, mapping seabed habitats with remote sensing and in situ visual survey of fish assemblage by snorkeling were conducted in coral reefs in Spermonde Archipelago, Indonesia. ALOS AVNIR-2 multi-band imagery on 14 October 2010 was analyzed to map four habitats: live coral, dead coral, seagrass and sand-rubble. Groundtruth data were obtained using towed video camera and sidescan sonar in May and June 2011. Depth-Invariant indices (DI-indices) based on ratios of radiance values between bands were applied as a water column correction. Overall classification accuracy in Tau-coefficient of mapping with the DI-indices (0.66) didn't differ significantly (p<0.05) from that with the radiance values (0.63). Concerning visual fish survey, 12 fish groups were identified and numbers of individuals belonging to each group were counted along a transect of approximately 100m at 18 sites. We calculated Spearman's rank correlation between abundance (Ind. /100m) of every fish group along a transect and the ratio of each habitat area mapped with DI-indices inside the circle with 50m-diameter which includes the fish transect. We detected significant correlations between abundance of five fish groups and specific habitats, especially butterflyfish and live coral. This result corresponds to the past reports that butterflyfish was a good indicator of healthy corals, suggesting meaningfulness of studying relationships between fish abundance and spatial distribution of habitats in larger scale.

  19. DNA barcode-based molecular identification system for fish species.

    PubMed

    Kim, Sungmin; Eo, Hae-Seok; Koo, Hyeyoung; Choi, Jun-Kil; Kim, Won

    2010-12-01

    In this study, we applied DNA barcoding to identify species using short DNA sequence analysis. We examined the utility of DNA barcoding by identifying 53 Korean freshwater fish species, 233 other freshwater fish species, and 1339 saltwater fish species. We successfully developed a web-based molecular identification system for fish (MISF) using a profile hidden Markov model. MISF facilitates efficient and reliable species identification, overcoming the limitations of conventional taxonomic approaches. MISF is freely accessible at http://bioinfosys.snu.ac.kr:8080/MISF/misf.jsp . PMID:21110132

  20. Comparison of visual survey and seining methods for estimating abundance of an endangered, benthic stream fish

    USGS Publications Warehouse

    Jordan, F.; Jelks, H.L.; Bortone, S.A.; Dorazio, R.M.

    2008-01-01

    We compared visual survey and seining methods for estimating abundance of endangered Okaloosa darters, Etheostoma okaloosae, in 12 replicate stream reaches during August 2001. For each 20-m stream reach, two divers systematically located and marked the position of darters and then a second crew of three to five people came through with a small-mesh seine and exhaustively sampled the same area. Visual surveys required little extra time to complete. Visual counts (24.2 ?? 12.0; mean ?? one SD) considerably exceeded seine captures (7.4 ?? 4.8), and counts from the two methods were uncorrelated. Visual surveys, but not seines, detected the presence of Okaloosa darters at one site with low population densities. In 2003, we performed a depletion removal study in 10 replicate stream reaches to assess the accuracy of the visual survey method. Visual surveys detected 59% of Okaloosa darters present, and visual counts and removal estimates were positively correlated. Taken together, our comparisons indicate that visual surveys more accurately and precisely estimate abundance of Okaloosa darters than seining and more reliably detect presence at low population densities. We recommend evaluation of visual survey methods when designing programs to monitor abundance of benthic fishes in clear streams, especially for threatened and endangered species that may be sensitive to handling and habitat disturbance. ?? 2007 Springer Science+Business Media, Inc.

  1. Demographic modeling of selected fish species with RAMAS

    SciTech Connect

    Saila, S.; Martin, B.; Ferson, S.; Ginzburg, L.; Millstein, J. )

    1991-03-01

    The microcomputer program RAMAS 3 developed for EPRI, has been used to model the intrinsic natural variability of seven important fish species: cod, Atlantic herring, yellowtail flounder, haddock, striped bass, American shad and white perch. Demographic data used to construct age-based population models included information on spawning biology, longevity, sex ratio and (age-specific) mortality and fecundity. These data were collected from published and unpublished sources. The natural risks of extinction and of falling below threshold population abundances (quasi-extinction) are derived for each of the seven fish species based on measured and estimated values for their demographic parameters. The analysis of these species provides evidence that including density-dependent compensation in the demographic model typically lowers the expected chance of extinction. This is because if density dependence generally acts as a restoring force it seems reasonable to conclude that models which include density dependence would exhibit less fluctuation than models without compensation since density-dependent populations experience a pull towards equilibrium. Since extinction probabilities are determined by the size of the fluctuation of population abundance, models without density dependence will show higher risks of extinction, given identical circumstances. Thus, models without compensation can be used as conservative estimators of risk, that is, if a compensation-free model yields acceptable extinction risk, adding compensation will not increase this risk. Since it is usually difficult to estimate the parameters needed for a model with compensation, such conservative estimates of the risks of extinction based on a model without compensation are very useful in the methodology of impact assessment. 103 refs., 19 figs., 10 tabs.

  2. FLOW REGIME, JUVENILE ABUNDANCE, AND THE ASSEMBLAGE STRUCTURE OF STREAM FISHES

    EPA Science Inventory

    The assemblage of fishes in a second-order stream in east-central Illinois was compared through seine sampling for two years with distinctly different flow regimes. In both years adult (age 0) fish were most abundant in late spring and early summer while juvenile (age 0) abundanc...

  3. Feeding ecology of some fish species occurring in artisanal fishery of Socotra Island (Yemen).

    PubMed

    Hassan Ali', Mohammed Kaed; Belluscio, Andrea; Ventura, Daniele; Ardizzone, Giandomenico

    2016-04-30

    The demersal species Lethrinus borbonicus, Lethrinus mahsena, Lethrinus microdon, Lethrinus nebulosus, Lutjanus bohar, Lutjanus gibbus, Lutjanus kasmira, Epinephelus fasciatus, Epinephelus stoliczkae, Carangoides gymnostethus and Euthynnus affinis are important coastal fishes species of the northern coast of Socotra (Yemen), exploited by local fishery. The biology and feeding ecology of these species are poorly known in the area. A total of 1239 specimens were sampled from the main fishing landing site of the island (Hadibo). Total length and weight were measured, stomach contents were analyzed, diet overlap, Fulton's Condition index, and trophic levels were estimated. C. gymnostethus, L. microdon and L. kasmira occupied the highest position (T=4.50), L. nebulosus occupied the lower one (TL=3.41). The role of the increasing abundance of small pelagic fish in the diet of many species after the upwelling event is evident, but also different feeding strategies are reported, according to fish ecology. PMID:26880127

  4. Foraminifera Species Richness, Abundance, and Diversity Research in Bolinas, California

    NASA Astrophysics Data System (ADS)

    Brunwin, N.; Ingram, Z.; Mendez, M.; Sandoval, K.

    2015-12-01

    Foraminifera are abundant, diverse, respond rapidly to environmental change, and are present in all marine and estuarine environments, making them important indicator species. A survey of occurrence and distribution of foraminifera in the Bolinas Lagoon, Marin County, California was carried out by Hedman in 1975, but no study since has focused on foraminiferal composition within this important ecosystem. In July 2015, the Careers in Science (CiS) Intern Program collected samples at 12 sites previously examined in the 1975 study. Thirty-six samples were collected from the upper few centimeters of sediment from a variety of intertidal and subtidal environments within the lagoon. Foraminifera from each sample were isolated, identified and species richness, abundance and diversity quantified. Furthermore, comparisons of faunal composition represented in our recent collection and that of Hedman's 1975 report are made.

  5. Fluctuations in production and abundance of commercial species in the Red Lakes, Minnesota, with special reference to changes in the walleye population

    USGS Publications Warehouse

    Smith, Lloyd L., Jr.; Krefting, Laurits W.

    1954-01-01

    The Red Lakes in northwestern Minnesota comprise 275,000 acres of water which support a commercial fishery producing up to 1.5 million pounds of fish per year. Walleye, Stizostedion vitreum vitreum (Mitchill), and yellow perch, Perca flavescens (Mitchill), are the principal species. Statistics for the past 37 years have been analyzed and fluctuations in the abundance of the important species calculated for the 24-year period, 1930–1953. The fishing is carried on exclusively with 3 1/2-inch-mesh (extension measure) gill nets by Chippewa Indians and the catch is marketed through a cooperative fishery enterprise. There have been wide fluctuations in the abundance of principal species but, although fishing effort has increased greatly during the past few years no trends have developed. Changes in walleye abundance have been shown to be independent of changes or levels of fishing effort, and to be determined by strength of individual year classes. Gear competition has no effect on abundance estimates. Strength of year classes is not correlated with size of brood stock, abundance of competing species, or amount of hatchery fish planted. Weather conditions cannot be correlated with observed changes in strength of year classes. Implications for management include provision of adequate prediction of abundance, and annual adjustment of fishing practices to make greatest use of the available stock. Gear limitations should be designed to secure harvest at optimum size of fish and to provide a suitable economic status for the fisherman.

  6. Abundance anomaly of the 13C species of CCH

    NASA Astrophysics Data System (ADS)

    Sakai, N.; Saruwatari, O.; Sakai, T.; Takano, S.; Yamamoto, S.

    2010-03-01

    Aims: We have observed the N = 1-0 lines of CCH and its 13C isotopic species toward a cold dark cloud, TMC-1 and a star-forming region, L1527, to investigate the 13C abundances and formation pathways of CCH. Methods: The observations have been carried out with the IRAM 30 m telescope. Results: We have successfully detected the lines of 13CCH and C13CH toward the both sources and found a significant intensity difference between the two 13C isotopic species. The [C13CH] /[13CCH] abundance ratios are 1.6 ± 0.4 (3σ) and 1.6 ± 0.1 (3σ) for TMC-1 and L1527, respectively. The abundance difference between C13CH and 13CCH means that the two carbon atoms of CCH are not equivalent in the formation pathway. On the other hand, the [CCH]/[C13CH] and [CCH]/[13CCH] ratios are evaluated to be larger than 170 and 250 toward TMC-1, and to be larger than 80 and 135 toward L1527, respectively. Therefore, both of the 13C species are significantly diluted in comparison with the interstellar 12C/13C ratio of 60. The dilution is discussed in terms of a behavior of 13C in molecular clouds.

  7. Measurement scale in maximum entropy models of species abundance

    PubMed Central

    Frank, Steven A.

    2010-01-01

    The consistency of the species abundance distribution across diverse communities has attracted widespread attention. In this paper, I argue that the consistency of pattern arises because diverse ecological mechanisms share a common symmetry with regard to measurement scale. By symmetry, I mean that different ecological processes preserve the same measure of information and lose all other information in the aggregation of various perturbations. I frame these explanations of symmetry, measurement, and aggregation in terms of a recently developed extension to the theory of maximum entropy. I show that the natural measurement scale for the species abundance distribution is log-linear: the information in observations at small population sizes scales logarithmically and, as population size increases, the scaling of information grades from logarithmic to linear. Such log-linear scaling leads naturally to a gamma distribution for species abundance, which matches well with the observed patterns. Much of the variation between samples can be explained by the magnitude at which the measurement scale grades from logarithmic to linear. This measurement approach can be applied to the similar problem of allelic diversity in population genetics and to a wide variety of other patterns in biology. PMID:21265915

  8. Neutral theory and relative species abundance in ecology

    NASA Astrophysics Data System (ADS)

    Volkov, Igor; Banavar, Jayanth R.; Hubbell, Stephen P.; Maritan, Amos

    2003-08-01

    The theory of island biogeography asserts that an island or a local community approaches an equilibrium species richness as a result of the interplay between the immigration of species from the much larger metacommunity source area and local extinction of species on the island (local community). Hubbell generalized this neutral theory to explore the expected steady-state distribution of relative species abundance (RSA) in the local community under restricted immigration. Here we present a theoretical framework for the unified neutral theory of biodiversity and an analytical solution for the distribution of the RSA both in the metacommunity (Fisher's log series) and in the local community, where there are fewer rare species. Rare species are more extinction-prone, and once they go locally extinct, they take longer to re-immigrate than do common species. Contrary to recent assertions, we show that the analytical solution provides a better fit, with fewer free parameters, to the RSA distribution of tree species on Barro Colorado Island, Panama, than the lognormal distribution.

  9. Fish abundances in shoreline habitats and submerged aquatic vegetation in a tidal freshwater embayment of the Potomac River.

    PubMed

    Kraus, Richard T; Jones, R Christian

    2012-05-01

    Submerged aquatic vegetation (SAV) is considered an important habitat for juvenile and small forage fish species, but many long-term recruitment surveys do not effectively monitor fish communities in SAV. To better understand the impact of recent large increases of SAV on the fish community in tidal freshwater reaches of the Potomac River, we compared traditional seine sampling from shore with drop ring sampling of SAV beds (primarily Hydrilla) in a shallow water (depths, <1.5 m) embayment, Gunston Cove. To accomplish this, we developed species-specific catch efficiency values for the seine gear and calculated area-based density in both shoreline and SAV habitats in late summer of three different years (2007, 2008, and 2009). For the dominant species (Fundulus diaphanus, Lepomis macrochirus, Etheostoma olmstedi, Morone americana, Lepomis gibbosus, and Fundulus heteroclitus), density was nearly always higher in SAV, but overall, species richness was highest in shoreline habitats sampled with seines. Although historical monitoring of fish in Gunston Cove (and throughout Chesapeake Bay) is based upon seine sampling (and trawl sampling in deeper areas), the high densities of fish and larger areal extent of SAV indicated that complementary sampling of SAV habitats would produce more accurate trends in abundances of common species. Because drop ring samples cover much less area than seines and may miss rare species, a combination of methods that includes seine sampling is needed for biodiversity assessment. The resurgence of SAV in tidal freshwater signifies improving water quality, and methods we evaluated here support improved inferences about population trends and fish community structure as indicators of ecosystem condition. PMID:21713468

  10. 50 CFR Table 2c to Part 679 - Species Codes: FMP Forage Fish Species (all species of the following families)

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Species Codes: FMP Forage Fish Species (all species of the following families) 2c Table 2c to Part 679 Wildlife and Fisheries FISHERY...: FMP Forage Fish Species (all species of the following families) Species Description Code...

  11. 50 CFR Table 2c to Part 679 - Species Codes: FMP Forage Fish Species (all species of the following families)

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Species Codes: FMP Forage Fish Species (all species of the following families) 2c Table 2c to Part 679 Wildlife and Fisheries FISHERY...: FMP Forage Fish Species (all species of the following families) Species Description Code...

  12. Quantification of mesocosm fish and amphibian species diversity via environmental DNA metabarcoding.

    PubMed

    Evans, Nathan T; Olds, Brett P; Renshaw, Mark A; Turner, Cameron R; Li, Yiyuan; Jerde, Christopher L; Mahon, Andrew R; Pfrender, Michael E; Lamberti, Gary A; Lodge, David M

    2016-01-01

    Freshwater fauna are particularly sensitive to environmental change and disturbance. Management agencies frequently use fish and amphibian biodiversity as indicators of ecosystem health and a way to prioritize and assess management strategies. Traditional aquatic bioassessment that relies on capture of organisms via nets, traps and electrofishing gear typically has low detection probabilities for rare species and can injure individuals of protected species. Our objective was to determine whether environmental DNA (eDNA) sampling and metabarcoding analysis can be used to accurately measure species diversity in aquatic assemblages with differing structures. We manipulated the density and relative abundance of eight fish and one amphibian species in replicated 206-L mesocosms. Environmental DNA was filtered from water samples, and six mitochondrial gene fragments were Illumina-sequenced to measure species diversity in each mesocosm. Metabarcoding detected all nine species in all treatment replicates. Additionally, we found a modest, but positive relationship between species abundance and sequencing read abundance. Our results illustrate the potential for eDNA sampling and metabarcoding approaches to improve quantification of aquatic species diversity in natural environments and point the way towards using eDNA metabarcoding as an index of macrofaunal species abundance. PMID:26032773

  13. A Mixed-Method Approach for Quantifying Illegal Fishing and Its Impact on an Endangered Fish Species.

    PubMed

    Free, Christopher M; Jensen, Olaf P; Mendsaikhan, Bud

    2015-01-01

    Illegal harvest is recognized as a widespread problem in natural resource management. The use of multiple methods for quantifying illegal harvest has been widely recommended yet infrequently applied. We used a mixed-method approach to evaluate the extent, character, and motivations of illegal gillnet fishing in Lake Hovsgol National Park, Mongolia and its impact on the lake's fish populations, especially that of the endangered endemic Hovsgol grayling (Thymallus nigrescens). Surveys for derelict fishing gear indicate that gillnet fishing is widespread and increasing and that fishers generally use 3-4 cm mesh gillnet. Interviews with resident herders and park rangers suggest that many residents fish for subsistence during the spring grayling spawning migration and that some residents fish commercially year-round. Interviewed herders and rangers generally agree that fish population sizes are decreasing but are divided on the causes and solutions. Biological monitoring indicates that the gillnet mesh sizes used by fishers efficiently target Hovsgol grayling. Of the five species sampled in the monitoring program, only burbot (Lota lota) showed a significant decrease in population abundance from 2009-2013. However, grayling, burbot, and roach (Rutilus rutilus) all showed significant declines in average body size, suggesting a negative fishing impact. Data-poor stock assessment methods suggest that the fishing effort equivalent to each resident family fishing 50-m of gillnet 11-15 nights per year would be sufficient to overexploit the grayling population. Results from the derelict fishing gear survey and interviews suggest that this level of effort is not implausible. Overall, we demonstrate the ability for a mixed-method approach to effectively describe an illegal fishery and suggest that these methods be used to assess illegal fishing and its impacts in other protected areas. PMID:26625154

  14. A Mixed-Method Approach for Quantifying Illegal Fishing and Its Impact on an Endangered Fish Species

    PubMed Central

    Free, Christopher M.; Jensen, Olaf P.; Mendsaikhan, Bud

    2015-01-01

    Illegal harvest is recognized as a widespread problem in natural resource management. The use of multiple methods for quantifying illegal harvest has been widely recommended yet infrequently applied. We used a mixed-method approach to evaluate the extent, character, and motivations of illegal gillnet fishing in Lake Hovsgol National Park, Mongolia and its impact on the lake’s fish populations, especially that of the endangered endemic Hovsgol grayling (Thymallus nigrescens). Surveys for derelict fishing gear indicate that gillnet fishing is widespread and increasing and that fishers generally use 3–4 cm mesh gillnet. Interviews with resident herders and park rangers suggest that many residents fish for subsistence during the spring grayling spawning migration and that some residents fish commercially year-round. Interviewed herders and rangers generally agree that fish population sizes are decreasing but are divided on the causes and solutions. Biological monitoring indicates that the gillnet mesh sizes used by fishers efficiently target Hovsgol grayling. Of the five species sampled in the monitoring program, only burbot (Lota lota) showed a significant decrease in population abundance from 2009–2013. However, grayling, burbot, and roach (Rutilus rutilus) all showed significant declines in average body size, suggesting a negative fishing impact. Data-poor stock assessment methods suggest that the fishing effort equivalent to each resident family fishing 50-m of gillnet 11–15 nights per year would be sufficient to overexploit the grayling population. Results from the derelict fishing gear survey and interviews suggest that this level of effort is not implausible. Overall, we demonstrate the ability for a mixed-method approach to effectively describe an illegal fishery and suggest that these methods be used to assess illegal fishing and its impacts in other protected areas. PMID:26625154

  15. Tissue specific metal characterization of selected fish species in Pakistan.

    PubMed

    Ahmed, Mukhtiar; Ahmad, Taufiq; Liaquat, Muhammad; Abbasi, Kashif Sarfraz; Farid, Ibrahim Bayoumi Abdel; Jahangir, Muhammad

    2016-04-01

    Concentration of various metals, i.e., zinc (Zn), copper (Cu), lead (Pb), nickel (Ni), iron (Fe), manganese (Mn), chromium (Cr), and silver (Ag), was evaluated in five indigenous fish species (namely, silver carp, common carp, mahseer, thela fish, and rainbow trout), by using atomic absorption spectrophotometer. It is proved from this study that, overall, mahseer and rainbow trout had high amount of zinc, whereas thela fish and silver carp had high concentration of copper, chromium, silver, nickel, and lead, while common carp had highest amount of iron contents. Furthermore, a tissue-specific discrimination among various fish species was observed, where higher metal concentrations were noticed in fish liver, with decreasing concentration in other organs like skin, gills, and finally the least contents in fish muscle. Multivariate data analysis showed not only a variation in heavy metals among the tissues but also discrimination among the selected fish species. PMID:26951449

  16. Tidal amplitude and fish abundance in the mouth region of a small estuary.

    PubMed

    Becker, A; Whitfield, A K; Cowley, P D; Cole, V J; Taylor, M D

    2016-09-01

    Using an acoustic underwater camera (Dual Frequency IDentification SONar, DIDSON), the abundance and direction of movement of fishes > 80 mm total length (LT ) in the mouth of a small South African estuary during spring and neap tidal cycles were observed. While the sizes of fishes recorded were consistent across both tide cycles, the number of fishes passing the camera was significantly greater during the smaller neap tides. Schooling behaviour was more pronounced for fishes that were travelling into the estuary compared to fishes swimming towards the ocean. PMID:27325497

  17. When Can Species Abundance Data Reveal Non-neutrality?

    PubMed Central

    Al Hammal, Omar; Alonso, David; Etienne, Rampal S.; Cornell, Stephen J.

    2015-01-01

    Species abundance distributions (SAD) are probably ecology’s most well-known empirical pattern, and over the last decades many models have been proposed to explain their shape. There is no consensus over which model is correct, because the degree to which different processes can be discerned from SAD patterns has not yet been rigorously quantified. We present a power calculation to quantify our ability to detect deviations from neutrality using species abundance data. We study non-neutral stochastic community models, and show that the presence of non-neutral processes is detectable if sample size is large enough and/or the amplitude of the effect is strong enough. Our framework can be used for any candidate community model that can be simulated on a computer, and determines both the sampling effort required to distinguish between alternative processes, and a range for the strength of non-neutral processes in communities whose patterns are statistically consistent with neutral theory. We find that even data sets of the scale of the 50 Ha forest plot on Barro Colorado Island, Panama, are unlikely to be large enough to detect deviations from neutrality caused by competitive interactions alone, though the presence of multiple non-neutral processes with contrasting effects on abundance distributions may be detectable. PMID:25793889

  18. When can species abundance data reveal non-neutrality?

    PubMed

    Al Hammal, Omar; Alonso, David; Etienne, Rampal S; Cornell, Stephen J

    2015-03-01

    Species abundance distributions (SAD) are probably ecology's most well-known empirical pattern, and over the last decades many models have been proposed to explain their shape. There is no consensus over which model is correct, because the degree to which different processes can be discerned from SAD patterns has not yet been rigorously quantified. We present a power calculation to quantify our ability to detect deviations from neutrality using species abundance data. We study non-neutral stochastic community models, and show that the presence of non-neutral processes is detectable if sample size is large enough and/or the amplitude of the effect is strong enough. Our framework can be used for any candidate community model that can be simulated on a computer, and determines both the sampling effort required to distinguish between alternative processes, and a range for the strength of non-neutral processes in communities whose patterns are statistically consistent with neutral theory. We find that even data sets of the scale of the 50 Ha forest plot on Barro Colorado Island, Panama, are unlikely to be large enough to detect deviations from neutrality caused by competitive interactions alone, though the presence of multiple non-neutral processes with contrasting effects on abundance distributions may be detectable. PMID:25793889

  19. Which Models Are Appropriate for Six Subtropical Forests: Species-Area and Species-Abundance Models

    PubMed Central

    Wei, Shi Guang; Li, Lin; Chen, Zhen Cheng; Lian, Ju Yu; Lin, Guo Jun; Huang, Zhong Liang; Yin, Zuo Yun

    2014-01-01

    The species-area relationship is one of the most important topic in the study of species diversity, conservation biology and landscape ecology. The species-area relationship curves describe the increase of species number with increasing area, and have been modeled by various equations. In this paper, we used detailed data from six 1-ha subtropical forest communities to fit three species-area relationship models. The coefficient of determination and F ratio of ANOVA showed all the three models fitted well to the species-area relationship data in the subtropical communities, with the logarithm model performing better than the other two models. We also used the three species-abundance distributions, namely the lognormal, logcauchy and logseries model, to fit them to the species-abundance data of six communities. In this case, the logcauchy model had the better fit based on the coefficient of determination. Our research reveals that the rare species always exist in the six communities, corroborating the neutral theory of Hubbell. Furthermore, we explained why all species-abundance figures appeared to be left-side truncated. This was due to subtropical forests have high diversity, and their large species number includes many rare species. PMID:24755956

  20. SURROGATE SPECIES IN ASSESSING CONTAMINANT RISK FOR ENDANGERED FISHES

    EPA Science Inventory

    Rainbow trout, fathead minnows, and sheepshead minnows were tested as surrogate species to assess contaminant risk for 17 endangered fishes and one toad species. Acute toxicity tests were conducted with carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin in accord...

  1. Comparative metabolomic and ionomic approach for abundant fishes in estuarine environments of Japan

    PubMed Central

    Yoshida, Seiji; Date, Yasuhiro; Akama, Makiko; Kikuchi, Jun

    2014-01-01

    Environmental metabolomics or ionomics is widely used to characterize the effects of environmental stressors on the health of aquatic organisms. However, most studies have focused on liver and muscle tissues of fish, and little is known about how the other organs are affected by environmental perturbations and effects such as metal pollutants or eutrophication. We examined the metabolic and mineral profiles of three kinds of abundant fishes in estuarine ecosystem, yellowfin goby, urohaze-goby, and juvenile Japanese seabass sampled from Tsurumi River estuary, Japan. Multivariate analyses, including nuclear magnetic resonance-based metabolomics and inductively coupled plasma optical emission spectrometry-based ionomics approaches, revealed that the profiles were clustered according to differences among body tissues rather than differences in body size, sex, and species. The metabolic and mineral profiles of the muscle and fin tissues, respectively, suggest that these tissues are most appropriate for evaluating environmental perturbations. Such analyses will be highly useful in evaluating the environmental variation and diversity in aquatic ecosystems. PMID:25387575

  2. Marine protected areas facilitate parasite populations among four fished host species of central Chile.

    PubMed

    Wood, Chelsea L; Micheli, Fiorenza; Fernández, Miriam; Gelcich, Stefan; Castilla, Juan Carlos; Carvajal, Juan

    2013-11-01

    1. Parasites comprise a substantial proportion of global biodiversity and exert important ecological influences on hosts, communities and ecosystems, but our knowledge of how parasite populations respond to human impacts is in its infancy. 2. Here, we present the results of a natural experiment in which we used a system of highly successful marine protected areas and matched open-access areas in central Chile to assess the influence of fishing-driven biodiversity loss on parasites of exploited fish and invertebrate hosts. We measured the burden of gill parasites for two reef fishes (Cheilodactylus variegatus and Aplodactylus punctatus), trematode parasites for a keyhole limpet (Fissurella latimarginata), and pinnotherid pea crab parasites for a sea urchin (Loxechinus albus). We also measured host density for all four hosts. 3. We found that nearly all parasite species exhibited substantially greater density (# parasites m(-2)) in protected than in open-access areas, but only one parasite species (a gill monogenean of C. variegatus) was more abundant within hosts collected from protected relative to open-access areas. 4. These data indicate that fishing can drive declines in parasite abundance at the parasite population level by reducing the availability of habitat and resources for parasites, but less commonly affects the abundance of parasites at the infrapopulation level (within individual hosts). 5. Considering the substantial ecological role that many parasites play in marine communities, fishing and other human impacts could exert cryptic but important effects on marine community structure and ecosystem functioning via reductions in parasite abundance. PMID:23855822

  3. Distribution and abundance of stream fishes in relation to barriers: implications for monitoring stream recovery after barrier removal

    USGS Publications Warehouse

    Zydlewski, Joseph; Coghlan Jr., Stephen M.; Gardner, C.; Saunders, R.

    2011-01-01

    Dams are ubiquitous in coastal regions and have altered stream habitats and the distribution and abundance of stream fishes in those habitats by disrupting hydrology, temperature regime and habitat connectivity. Dam removal is a common restoration tool, but often the response of the fish assemblage is not monitored rigorously. Sedgeunkedunk Stream, a small tributary to the Penobscot River (Maine, USA), has been the focus of a restoration effort that includes the removal of two low-head dams. In this study, we quantified fish assemblage metrics along a longitudinal gradient in Sedgeunkedunk Stream and also in a nearby reference stream. By establishing pre-removal baseline conditions and associated variability and the conditions and variability immediately following removal, we can characterize future changes in the system associated with dam removal. Over 2 years prior to dam removal, species richness and abundance in Sedgeunkedunk Stream were highest downstream of the lowest dam, lowest immediately upstream of that dam and intermediate farther upstream; patterns were similar in the reference stream. Although seasonal and annual variation in metrics within each site was substantial, the overall upstream-to-downstream pattern along the stream gradient was remarkably consistent prior to dam removal. Immediately after dam removal, we saw significant decreases in richness and abundance downstream of the former dam site and a corresponding increase in fish abundance upstream of the former dam site. No such changes occurred in reference sites. Our results show that by quantifying baseline conditions in a small stream before restoration, the effects of stream restoration efforts on fish assemblages can be monitored successfully. These data set the stage for the long-term assessment of Sedgeunkedunk Stream and provide a simple methodology for assessment in other restoration projects.

  4. Species assemblages of pelagic fish embryos in the southern North Sea between 1984 and 2000

    NASA Astrophysics Data System (ADS)

    von Westernhagen, Hein; Dethlefsen, Volkert; Bade, Tim; Wosniok, Werner

    2002-02-01

    The occurrence and abundance of the pelagic eggs of southern North Sea spring-spawning fish were analysed between 1984 and 2000. Species number varied between six (1986) and 14 (1999) and was positively correlated with sea surface temperature. With one exception, dab eggs were always the most abundant and usually highly dominant. Ranking of species depended on temperature, but no significant differences in ranking between years was discernible. Although with the increase in temperature in the 1990s a change in species assemblage was evident [species belonging to the boreal-Mediterranean (Lusitanian) group became more apparent in the species assemblage] this did not lead to an increased species diversity (Shannon Index) or a change in other community parameters. It appears that the recent developments regarding spawning stock biomass of commercial North Sea fish is reflected in the declining egg abundance of the respective commercial and larger species (i.e. cod, flounder, plaice) and an increase in abundance of the eggs of small species (i.e. long rough dab, rockling) over the years.

  5. Species-specific patterns of aggregation of wild fish around fish farms

    NASA Astrophysics Data System (ADS)

    Dempster, T.; Sanchez-Jerez, P.; Uglem, I.; Bjørn, P.-A.

    2010-01-01

    Fish-farming structures are widespread in coastal waters and are highly attractive to wild fish. Several studies have estimated that tons to tens of tons of wild fish aggregate around fish farms. These estimates assumed that the majority of wild fish are concentrated immediately beneath farms, although this assumption has never been explicitly tested. We tested the hypothesis that abundances of wild fish would be greatest immediately beneath farms and progressively diminish with distance at 4 full-scale coastal salmon ( Salmo salar) farms in Norway. At each farm, fish were counted with a video-camera system at 5 different distances from the cages (farm = 0 m, 25, 50, 100 and 200 m) throughout the water column on three separate days. Combined across all locations and times, the total abundance of wild fish was 20 times greater at the farm than at the 200 m sampling distance. Saithe ( Pollachius virens) dominated assemblages at all 4 farms and were consistently significantly more abundant at the farm than at the 25-200 m distances. This 'tight aggregation' around farms corresponds to the reliance of saithe on waste feed when they school near farms. In contrast, patterns of distribution of both cod ( Gadus morhua) and poor cod ( Trisopterus minutus) varied among farms, with either highest abundances at the farm or a more even distribution of abundance across all 5 distances sampled. No specific pattern of aggregation was evident for the bottom-dwelling haddock ( Melanogrammus aeglefinus). Our results suggest that the present 100 m no-fishing zone around salmon farms protects the greatest proportion of farm-aggregated saithe and cod from fishing during the daytime. However, whether this reduces their overall susceptibility to fishing requires further research regarding nighttime distribution and movements.

  6. Species composition and abundance of Brevipalpus spp. on different citrus species in Mexican orchards.

    PubMed

    Salinas-Vargas, D; Santillán-Galicia, M T; Valdez-Carrasco, J; Mora-Aguilera, G; Atanacio-Serrano, Y; Romero-Pescador, P

    2013-08-01

    We studied the abundance of Brevipalpus spp. in citrus orchards in the Mexican states of Yucatan, Quintana Roo and Campeche. Mites were collected from 100 trees containing a mixture of citrus species where sweet orange was always the main species. Eight collections were made at each location from February 2010 to February 2011. Mites from the genus Brevipalpus were separated from other mites surveyed and their abundance and relationships with the different citrus species were quantified throughout the collection period. A subsample of 25% of the total Brevipalpus mites collected were identified to species level and the interaction of mite species and citrus species were described. Brevipalpus spp. were present on all collection dates and their relative abundance was similar on all citrus species studies. The smallest number of mites collected was during the rainy season. Brevipalpus phoenicis (Geijskes) and Brevipalpus californicus (Banks) were the only two species present and they were found in all locations except Campeche, where only B. phoenicis was present. Yucatan and Campeche are at greater risk of leprosis virus transmission than Quintana Roo because the main vector, B. phoenicis, was more abundant than B. californicus. The implications of our results for the design of more accurate sampling and control methods for Brevipalpus spp. are discussed. PMID:23949863

  7. How climate warming impacts the distribution and abundance of two small flatfish species in the North Sea

    NASA Astrophysics Data System (ADS)

    van Hal, Ralf; Smits, Kalle; Rijnsdorp, Adriaan D.

    2010-07-01

    Climate change, specifically temperature, affects the distribution and densities of species in marine and terrestrial ecosystems. Here, we looked at the effect of temperature during winter and spawning period on latitudinal range shifts and changes in abundance of two non-commercial North Sea fish species, solenette ( Buglossidium luteum) and scaldfish ( Arnoglossus laterna). Both species have increased in abundance and moved to the north since the late 1980s, coinciding with a series of mild winters. In 1996, following a very cold winter, the abundance of both species temporarily decreased as they retracted to the south. The shift in temperature affected adult habitat conditions, allowing them to immigrate into new areas where they subsequently reproduced successfully. We can conclude this because recruitment improved following the increase in abundance. The recruitment relates significantly to the higher adult stock and higher temperatures. The predictions of higher average temperatures and milder winters in the North Sea make it likely that these species will increase further in abundance and move northward. The observed increase in abundance of these small flatfish species will affect the North Sea food web and therefore commercial species, e.g. plaice, by predation on juveniles and competition for benthic food resources.

  8. Differences in ecological structure, function, and native species abundance between native and invaded Hawaiian streams.

    PubMed

    Holitzki, Tara M; MacKenzie, Richard A; Wiegner, Tracy N; McDermid, Karla J

    2013-09-01

    Poeciliids, one of the most invasive species worldwide, are found on almost every continent and have been identified as an "invasive species of concern" in the United States, New Zealand, and Australia. Despite their global prevalence, few studies have quantified their impacts on tropical stream ecosystem structure, function, and biodiversity. Utilizing Hawaiian streams as model ecosystems, we documented how ecological structure, function, and native species abundance differed between poeciliid-free and poeciliid-invaded tropical streams. Stream nutrient yields, benthic biofilm biomass, densities of macroinvertebrates and fish, and community structures of benthic algae, macroinvertebrates, and fish were compared between streams with and without established poeciliid populations on the island of Hawai'i, Hawaii, USA. Sum nitrate (sigmaNO3(-) = NO3(-) + NO2(-)), total nitrogen, and total organic carbon yields were eight times, six times, and five times higher, respectively, in poeciliid streams than in poeciliid-free streams. Benthic biofilm ash-free dry mass was 1.5x higher in poeciliid streams than in poeciliid-free streams. Percentage contributions of chironomids and hydroptilid caddisflies to macroinvertebrate densities were lower in poeciliid streams compared to poeciliid-free streams, while percentage contributions of Cheumatopsyche analis caddisflies, Dugesia sp. flatworms, and oligochaetes were higher. Additionally, mean densities of native gobies were two times lower in poeciliid streams than in poeciliid-free ones, with poeciliid densities being approximately eight times higher than native fish densities. Our results, coupled with the wide distribution of invasive poeciliids across Hawaii and elsewhere in the tropics, suggest that poeciliids may negatively impact the ecosystem structure, function, and native species abundance of tropical streams they invade. This underscores the need for increased public awareness to prevent future introductions and for

  9. Investigating the association of fish abundance and biomass with cold-water corals in the deep Northeast Atlantic Ocean using a generalised linear modelling approach

    NASA Astrophysics Data System (ADS)

    Biber, Matthias F.; Duineveld, Gerard C. A.; Lavaleye, Marc S. S.; Davies, Andrew J.; Bergman, Magda J. N.; van den Beld, Inge M. J.

    2014-01-01

    Cold-water corals (CWC) can form complex three-dimensional structures that can support a diverse macro- and megafaunal community. These reef structures provide important biogenic habitats that can act as refuge, feeding, spawning and nursery areas for fish. However, quantitative data assessing the linkage between CWC and fish are scarce. The North Atlantic Ocean is a key region in the worldwide distribution of Lophelia pertusa, which is thought to be the most widespread frame-work forming cold-water coral species in the world. This study examined the relationship between fish and CWC reefs in the northeast Atlantic Ocean by means of video and remotely sensed data from three different CWC communities (Rockall Bank, Hatton Bank and the Belgica Mound Province). Using a tethered camera system, 37 transects were recorded during a period of 8 years. Fish-coral association was investigated using a generalised linear modelling (GLM) approach. Overall, Lepidion eques was the most abundant fish species present (143 ind. ha-1). Other common species were Sigmops bathyphilus (17 ind. ha-1), Synaphobranchus kaupii (15 ind. ha-1), Helicolenus dactylopterus (16 ind. ha-1) and Mora moro (7 ind. ha-1). The highest fish biomass was measured for Lophius piscatorius (26.3 kg ha-1). Other species with a high biomass were Helicolenus dactylopterus (4.3 kg ha-1), Lepidion eques (13.2 kg ha-1) and Mora moro (7.8 kg ha-1). Overall, no significant difference in fish abundance and biomass was found at coral framework habitats compared to non-coral areas. The relationship between fish and coral framework varied among fish species and study site. Fish count and length modelling results showed that terrain variables explain a small proportion of the variation of our data. Depth, coral-framework and terrain rugosity were generally the most important explanatory variables, but this varied with species and study site.

  10. Hankin and Reeves' approach to estimating fish abundance in small streams: Limitations and alternatives

    USGS Publications Warehouse

    Thompson, W.L.

    2003-01-01

    Hankin and Reeves' (1988) approach to estimating fish abundance in small streams has been applied in stream fish studies across North America. However, their population estimator relies on two key assumptions: (1) removal estimates are equal to the true numbers of fish, and (2) removal estimates are highly correlated with snorkel counts within a subset of sampled stream units. Violations of these assumptions may produce suspect results. To determine possible sources of the assumption violations, I used data on the abundance of steelhead Oncorhynchus mykiss from Hankin and Reeves' (1988) in a simulation composed of 50,000 repeated, stratified systematic random samples from a spatially clustered distribution. The simulation was used to investigate effects of a range of removal estimates, from 75% to 100% of true fish abundance, on overall stream fish population estimates. The effects of various categories of removal-estimates-to-snorkel-count correlation levels (r = 0.75-1.0) on fish population estimates were also explored. Simulation results indicated that Hankin and Reeves' approach may produce poor results unless removal estimates exceed at least 85% of the true number of fish within sampled units and unless correlations between removal estimates and snorkel counts are at least 0.90. A potential modification to Hankin and Reeves' approach is the inclusion of environmental covariates that affect detection rates of fish into the removal model or other mark-recapture model. A potential alternative approach is to use snorkeling combined with line transect sampling to estimate fish densities within stream units. As with any method of population estimation, a pilot study should be conducted to evaluate its usefulness, which requires a known (or nearly so) population of fish to serve as a benchmark for evaluating bias and precision of estimators.

  11. Introduced species and abiotic factors affect longitudinal variation in small fish assemblages in the Wind River watershed, Wyoming

    USGS Publications Warehouse

    Lionberger, P.S.; Hubert, W.A.

    2007-01-01

    We assessed longitudinal variation in small fish assemblages in the Wind River watershed upstream from Boysen Reservoir, Wyoming and into the reservoir. Twenty-six species were found in the study area, and 12 of the species were believed to have been introduced since settlement by Europeans. Additions and losses of fish species occurred with downstream progression, especially the addition of introduced species. Introduced species increased from 25% of the total number of species in the upper-most river segment (31.5-35.3 km upstream from the reservoir), to 46% in the river segment immediately upstream from the reservoir, to 48% in the reservoir. The most abundant species in the riverine portion of the watershed was the introduced sand shiner (Notropis stramineus). The results suggest that cyprinid species introduced to the upstream watershed and Boysen Reservoir are influencing small fish assemblages upstream from the reservoir and may be impacting native fishes, particularly native cyprinids.

  12. Analyzing fractal property of species abundance distribution and diversity indexes.

    PubMed

    Su, Qiang

    2016-03-01

    Community diversity is usually characterized by numerical indexes; however it indeed depends on the species abundance distribution (SAD). Diversity indexes and SAD are based on the same information but treating as separate themes. Ranking species abundance from largest to smallest, the decreasing pattern can give the information about the SAD. Frontier proposed such SAD might be a fractal structure, and first applied the Zipf-Mandelbrot model to the SAD study. However, this model fails to include the Zipf model, and also fails to ensure an integer rank. In this study, a fractal model of SAD was reconstructed, and tested with 104 community samples from 8 taxonomic groups. The results show that there was a good fit of the presented model. Fractal parameter (p) determines the SAD of a community. The ecological significance of p relates to the "dominance" of a community. The correlation between p and classical diversity indexes show that Shannon index decreases and Simpson index increases as p increases. The main purpose of this paper is not to compare with other SADs models; it simply provides a new interpretation of SAD model construction, and preliminarily integrates diversity indexes and SAD model into a broader perspective of community diversity. PMID:26746388

  13. Metagenomic abundance estimation and diagnostic testing on species level

    PubMed Central

    Lindner, Martin S.; Renard, Bernhard Y.

    2013-01-01

    One goal of sequencing-based metagenomic community analysis is the quantitative taxonomic assessment of microbial community compositions. In particular, relative quantification of taxons is of high relevance for metagenomic diagnostics or microbial community comparison. However, the majority of existing approaches quantify at low resolution (e.g. at phylum level), rely on the existence of special genes (e.g. 16S), or have severe problems discerning species with highly similar genome sequences. Yet, problems as metagenomic diagnostics require accurate quantification on species level. We developed Genome Abundance Similarity Correction (GASiC), a method to estimate true genome abundances via read alignment by considering reference genome similarities in a non-negative LASSO approach. We demonstrate GASiC’s superior performance over existing methods on simulated benchmark data as well as on real data. In addition, we present applications to datasets of both bacterial DNA and viral RNA source. We further discuss our approach as an alternative to PCR-based DNA quantification. PMID:22941661

  14. Species composition, distribution and abundance of chaetodontidae along reef transects in the Flores Sea

    NASA Astrophysics Data System (ADS)

    Adrim, Mohammad; Hutomo, Malikusworo

    Observations on chaetodontid fishes were made by applying a visual census technique at 13 coral reef locations in the Flores Sea region in October and November 1984. These observations were made along 50 m transect lines, parallel to the shore or the reef edge at depths between 3 to 12 m. Twenty-three species of Chaetodontidae were observed, representing three genera: Chaetodon (20 species), Heniochus (2 species) and Forcipiger (1 species). Chaetodon kleini, C. trifasciatus, C. melannotus and C. baronessa proved to be the most abundant species, and among them C. kleini and C. trifasciatus were the most widely distributed ones. Chaetodon semeion and C. mertensi were the rarest species. The greatest number of individuals (77) was counted at station 4.268 near Tanjung Burung, Sumbawa, while the greatest number of species (14) was observed at station 4.257, north of Komodo. The lowest number of individuals (17) was counted at station 4.175 near P. Bahuluang, Salayer, while station 4.251 near Teluk Slawi, Komodo, was inhabited by the smallest numbver of species (2). Numerical classification by using the Bray Curtis dissimilarity index resulted in three groups of entities. The first group was characterized by predomination of C. kleini and the second by predomination of C. melannotus. The third one was a loose group not characterized by any predominant species. The analyses indicated that the similarities of the chaetodontid communities between locations are not related to the distance between them, but rather to habitat conditions. For example predomination of C. melannotus is strongly related to the predomination of soft coral. Compared to other areas of Indonesia, e.g. Bali, Seribu Islands, Batam, Sunda Strait, and Ambon Bay, the Flores Sea reefs have a more abundant and more diverse chaetodontid fauna.

  15. Parasite fauna of selected fish species of Lake Miedwie.

    PubMed

    Sobecka, Ewa; Piasecki, Wojciech

    2002-01-01

    A total of 136 fishes, representing 9 species (perch, Perca fluviatilis L.; pike, Esox lucius L.; European eel, Anguilla anguilla (L.); common bream, Abramis brama (L.); roach, Rutilus rutilus (L.); tench Tinca tinca (L.); European whitefish, Coregonus lavaretus (L.); vendace, Coregonus albula (L.); and zander, Sander lucioperca (L.)), from Lake Miedwie were studied within 1997-1999. The necropsies yielded 41 parasite species (taxa). The most diversified were parasite faunas of pike (19 parasite species) and perch (16 species). The parasites found represented 13 higher taxa: Monera, Fungi, Protista, Myxozoa, Monogenea, Cestoda, Digenea, Nematoda, Acanthocephala, Branchiura, Copepoda, Mollusca, and Acarina. The parasites affecting fishes of Lake Miedwie exhibited diversified host-specificity. The most fish species were infected by metacercariae of Diplostomum spp. (8 fish species) and Tylodelphys clavata (7). Three fish species harboured: Ichthyocotylurus platycephalus, Ergasilus sieboldi, and glochidia Unionidae gen. sp. while Dermocystidium sp., Trichodinella epizootica, Henneguya psorospermica, Triaenophorus nodulosus, Posthodiplostomum cuticula, and Camallanus lacustris parasitised two host species. The remaining parasites were found in single fish species. PMID:16888943

  16. SPECIES-ABUNDANCE-BIOMASS RESPONSES BY ESTUARINE MACROBENTHOS TO SEDIMENT CHEMICAL CONTAMINATION.

    EPA Science Inventory

    Macrobenthic community responses can be measured through concerted changes in univariate metrics, including species richness, total abundance, and total biomass. The classic model of pollution effects on marine macroinvertebrate communities recognizes that species/abundance/bioma...

  17. Distribution of nekton species and abundance within and among four Oregon estuaries

    EPA Science Inventory

    Crabs, shrimps and fishes provide valued ecosystem goods and services to communities of the Pacific Northwest, including species that are fished for food and recreation and those that serve as prey for fished species. In the face of increasing use of these services and potential...

  18. Oral vaccination of fish: Lessons from humans and veterinary species.

    PubMed

    Embregts, Carmen W E; Forlenza, Maria

    2016-11-01

    The limited number of oral vaccines currently approved for use in humans and veterinary species clearly illustrates that development of efficacious and safe oral vaccines has been a challenge not only for fish immunologists. The insufficient efficacy of oral vaccines is partly due to antigen breakdown in the harsh gastric environment, but also to the high tolerogenic gut environment and to inadequate vaccine design. In this review we discuss current approaches used to develop oral vaccines for mass vaccination of farmed fish species. Furthermore, using various examples from the human and veterinary vaccine development, we propose additional approaches to fish vaccine design also considering recent advances in fish mucosal immunology and novel molecular tools. Finally, we discuss the pros and cons of using the zebrafish as a pre-screening animal model to potentially speed up vaccine design and testing for aquaculture fish species. PMID:27018298

  19. Classification of species attributes for Pacific Northwest freshwater fishes

    USGS Publications Warehouse

    Zaroban, D.W.; Mulvey, M.P.; Maret, T.R.; Hughes, R.M.; Merritt, G.D.

    1999-01-01

    Fish assemblages integrate physical and chemical habitat conditions and are used to evaluate the condition of water resources in the Pacific Northwest. To facilitate such evaluations, we classified each of the 132 freshwater fish species known to occur in the Pacific Northwest (Idaho, Oregon, Washington) by its origin, overall pollution tolerance, adult habitat, adult feeding, and water temperature preference. Recommendations from regional fishery experts, published literature, and the aggregate experience of the authors were used to classify species. The attribute classifications were responsive to human disturbance of aquatic habitats when applied to fish assemblages sampled from throughout the region. Our attribute classification of fish species promotes use of fish assemblages to evaluate water resource conditions regionally and fosters greater acceptance of biological measures of water resource quality.

  20. Astrochem: Abundances of chemical species in the interstellar medium

    NASA Astrophysics Data System (ADS)

    Maret, Sébastien; Bergin, Edwin A.

    2015-07-01

    Astrochem computes the abundances of chemical species in the interstellar medium, as function of time. It studies the chemistry in a variety of astronomical objects, including diffuse clouds, dense clouds, photodissociation regions, prestellar cores, protostars, and protostellar disks. Astrochem reads a network of chemical reactions from a text file, builds up a system of kinetic rates equations, and solves it using a state-of-the-art stiff ordinary differential equation (ODE) solver. The Jacobian matrix of the system is computed implicitly, so the resolution of the system is extremely fast: large networks containing several thousands of reactions are usually solved in a few seconds. A variety of gas phase process are considered, as well as simple gas-grain interactions, such as the freeze-out and the desorption via several mechanisms (thermal desorption, cosmic-ray desorption and photo-desorption). The computed abundances are written in a HDF5 file, and can be plotted in different ways with the tools provided with Astrochem. Chemical reactions and their rates are written in a format which is meant to be easy to read and to edit. A tool to convert the chemical networks from the OSU and KIDA databases into this format is also provided. Astrochem is written in C, and its source code is distributed under the terms of the GNU General Public License (GPL).

  1. Fuel breaks affect nonnative species abundance in Californian plant communities

    USGS Publications Warehouse

    Merriam, K.E.; Keeley, J.E.; Beyers, J.L.

    2006-01-01

    We evaluated the abundance of nonnative plants on fuel breaks and in adjacent untreated areas to determine if fuel treatments promote the invasion of nonnative plant species. Understanding the relationship between fuel treatments and nonnative plants is becoming increasingly important as federal and state agencies are currently implementing large fuel treatment programs throughout the United States to reduce the threat of wildland fire. Our study included 24 fuel breaks located across the State of California. We found that nonnative plant abundance was over 200% higher on fuel breaks than in adjacent wildland areas. Relative nonnative cover was greater on fuel breaks constructed by bulldozers (28%) than on fuel breaks constructed by other methods (7%). Canopy cover, litter cover, and duff depth also were significantly lower on fuel breaks constructed by bulldozers, and these fuel breaks had significantly more exposed bare ground than other types of fuel breaks. There was a significant decline in relative nonnative cover with increasing distance from the fuel break, particularly in areas that had experienced more numerous fires during the past 50 years, and in areas that had been grazed. These data suggest that fuel breaks could provide establishment sites for nonnative plants, and that nonnatives may invade surrounding areas, especially after disturbances such as fire or grazing. Fuel break construction and maintenance methods that leave some overstory canopy and minimize exposure of bare ground may be less likely to promote nonnative plants. ?? 2006 by the Ecological Society of America.

  2. Effects of fish density and relative abundance on competition between larval lake herring and lake whitefish for zooplankton

    USGS Publications Warehouse

    Todd, Thomas N.; Davis, Bruce M.

    1995-01-01

    Competition for zooplankton between larval lake herring (Coregonus artedi) and lake whitefish (C. clupeaformis) was compared in mesocosm experiments in a small lake. Both species were combined in test enclosures at relative abundances of 1:1 or 1:4 lake herring to lake whitefish at densities of 500; 1, 000; and 2, 000 fish per cage, and were allowed to feed ad libitum on available zooplankton. After 60 days, at 500 fish per cage and a 1:1 ratio, lake whitfish were significantly larger than lake herring. At 1, 000 and 2, 000 fish per cage, lake herring and lake whitefish exhibited similar depressed growth rates. Survival was lower (30-50%) in the nets with 2, 000 fish than in the lower fish densities. We suspect that diet similarities of juvenile lake herring and lake whitefish in addition to the larger size and more aggressive behavior of larval lake whitefish resulted in the depressed growth and poorer survival for lake herring.

  3. Modeling of Valued Fish Species in River Networks

    EPA Science Inventory

    Riverine fish provide many ecosystem services in support of human well-being, including food, recreation, and biodiversity. Under future drivers of land use and climate change, inland waters are likely to be impaired, and conservation and protection of fish species and services ...

  4. Digenean species diversity in teleost fishes from the Gulf of Gabes, Tunisia (Western Mediterranean)

    PubMed Central

    Derbel, H.; Châari, M.; Neifar, L.

    2012-01-01

    This study is the first attempt to survey the diversity of fish digeneans in the Gulf of Gabes (southern coast of Tunisia). A total of 779 fishes belonging to 32 species were sampled. 53 species of Digenea belonging to 15 families were recorded. Among these species, 24 are reported for the first time from the coast of Tunisia. We report one new host record, Lecithochirium sp. from Sardinella aurita. The Hemiuridae is the dominant family. A host-parasite list is presented with the information on the prevalence, abundance and mean intensity of each species collected. The diversity of Digenea is compared with other localities in the Mediterranean Sea and the northern east of Tunisia. The Gulf of Gabes shows the lowest diversity linked to the anthropogenic activities and impact of exotic species. The use of Digenea as indicators of the state of the ecosystem is discussed. PMID:22550623

  5. Fish parasites in the Arctic deep-sea: Poor diversity in pelagic fish species vs. heavy parasite load in a demersal fish

    NASA Astrophysics Data System (ADS)

    Klimpel, Sven; Palm, Harry Wilhelm; Busch, Markus Wilhelm; Kellermanns, Esra; Rückert, Sonja

    2006-07-01

    A total of 219 deep-sea fishes belonging to five families were examined for the parasite fauna and stomach contents. The demersal fish Macrourus berglax, bathypelagic Bathylagus euryops, and mesopelagic Argentina silus, Borostomias antarcticus, Chauliodus sloani, and Lampanyctus macdonaldi were caught at 243-708 m trawling depth in the Greenland and the Irminger Sea in 2002. A total of 21 different parasite species, six Digenea, one Monogenea, two Cestoda, seven Nematoda, one Acanthocephala, and four Crustacea, were found. The parasite diversity in the meso- and bathypelagic environment was less diverse in comparison to the benthal. Macrourus berglax had the highest diversity (20 species), usually carrying 4-10 different parasite species (mean 7.1), whereas Bathylagus euryops harbored up to three and Argentina silus, Borostomias antarcticus, Chauliodus sloani and Lampanyctus macdonaldi each up to two species. Most Digenea, Cestoda, Nematoda, Acanthocephala, and Crustacea are known from a wide host range. Several of the encountered parasites occurred at a very low prevalence (<10%), indicating that the studied deep-sea fishes are most probably not instrumental to complete the parasite life cycles in the area of investigation. It is suggested that the lack of nutrients in the meso- and bathypelagial limits the abundance of potential first intermediate hosts of nematodes and cestodes, resulting in low infestation rates even of widely distributed, non-specific species. In contrast, the higher biomass in the benthic deep-sea environment increases the availability of potential intermediate hosts, such as molluscs for the digeneans, resulting in increased parasite diversity. Because many deep-sea fish have a generalistic feeding behavior, the observed different parasite diversity reflects a different depth range of the fish and not necessarily a specific fish feeding ecology.

  6. Methylmercury concentrations in six fish species from two Colombian rivers.

    PubMed

    Alvarez, Santiago; Jessick, Ashley M; Palacio, Jaime A; Kolok, Alan S

    2012-01-01

    The objective of this study was to determine whether fish collected from the La Miel or Nechí Rivers (Colombia) differed in muscle methyl mercury (meHg) concentration. Two fish from six different species were collected from markets adjacent to each river. Overall, fish collected from the market adjacent to the Nechí River contained higher levels of meHg. This result however is being driven by very high meHg concentrations in four individual fish, three of which are Pimelodid, long-whiskered catfish. These catfish may represent ideal sentinel organism for the detection of meHg contamination in Colombian rivers. PMID:22065125

  7. Microbial distribution and abundance in the digestive system of five shipworm species (Bivalvia: Teredinidae).

    PubMed

    Betcher, Meghan A; Fung, Jennifer M; Han, Andrew W; O'Connor, Roberta; Seronay, Romell; Concepcion, Gisela P; Distel, Daniel L; Haygood, Margo G

    2012-01-01

    Marine bivalves of the family Teredinidae (shipworms) are voracious consumers of wood in marine environments. In several shipworm species, dense communities of intracellular bacterial endosymbionts have been observed within specialized cells (bacteriocytes) of the gills (ctenidia). These bacteria are proposed to contribute to digestion of wood by the host. While the microbes of shipworm gills have been studied extensively in several species, the abundance and distribution of microbes in the digestive system have not been adequately addressed. Here we use Fluorescence In-Situ Hybridization (FISH) and laser scanning confocal microscopy with 16S rRNA directed oligonucleotide probes targeting all domains, domains Bacteria and Archaea, and other taxonomic groups to examine the digestive microbiota of 17 specimens from 5 shipworm species (Bankia setacea, Lyrodus pedicellatus, Lyrodus massa, Lyrodus sp. and Teredo aff. triangularis). These data reveal that the caecum, a large sac-like appendage of the stomach that typically contains large quantities of wood particles and is considered the primary site of wood digestion, harbors only very sparse microbial populations. However, a significant number of bacterial cells were observed in fecal pellets within the intestines. These results suggest that due to low abundance, bacteria in the caecum may contribute little to lignocellulose degradation. In contrast, the comparatively high population density of bacteria in the intestine suggests a possible role for intestinal bacteria in the degradation of lignocellulose. PMID:23028923

  8. Microbial Distribution and Abundance in the Digestive System of Five Shipworm Species (Bivalvia: Teredinidae)

    PubMed Central

    Betcher, Meghan A.; Fung, Jennifer M.; Han, Andrew W.; O’Connor, Roberta; Seronay, Romell; Concepcion, Gisela P.; Distel, Daniel L.; Haygood, Margo G.

    2012-01-01

    Marine bivalves of the family Teredinidae (shipworms) are voracious consumers of wood in marine environments. In several shipworm species, dense communities of intracellular bacterial endosymbionts have been observed within specialized cells (bacteriocytes) of the gills (ctenidia). These bacteria are proposed to contribute to digestion of wood by the host. While the microbes of shipworm gills have been studied extensively in several species, the abundance and distribution of microbes in the digestive system have not been adequately addressed. Here we use Fluorescence In-Situ Hybridization (FISH) and laser scanning confocal microscopy with 16S rRNA directed oligonucleotide probes targeting all domains, domains Bacteria and Archaea, and other taxonomic groups to examine the digestive microbiota of 17 specimens from 5 shipworm species (Bankia setacea, Lyrodus pedicellatus, Lyrodus massa, Lyrodus sp. and Teredo aff. triangularis). These data reveal that the caecum, a large sac-like appendage of the stomach that typically contains large quantities of wood particles and is considered the primary site of wood digestion, harbors only very sparse microbial populations. However, a significant number of bacterial cells were observed in fecal pellets within the intestines. These results suggest that due to low abundance, bacteria in the caecum may contribute little to lignocellulose degradation. In contrast, the comparatively high population density of bacteria in the intestine suggests a possible role for intestinal bacteria in the degradation of lignocellulose. PMID:23028923

  9. Development of Solar Drying Model for Selected Cambodian Fish Species

    PubMed Central

    Hubackova, Anna; Kucerova, Iva; Chrun, Rithy; Chaloupkova, Petra; Banout, Jan

    2014-01-01

    A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6°C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg·h−1. Based on coefficient of determination (R2), chi-square (χ2) test, and root-mean-square error (RMSE), the most suitable models describing natural convection solar drying kinetics were Logarithmic model, Diffusion approximate model, and Two-term model for climbing perch and Nile tilapia, swamp eel and walking catfish and Channa fish, respectively. In case of electric oven drying, the Modified Page 1 model shows the best results for all investigated fish species except Channa fish where the two-term model is the best one. Sensory evaluation shows that most preferable fish is climbing perch, followed by Nile tilapia and walking catfish. This study brings new knowledge about drying kinetics of fresh water fish species in Cambodia and confirms the solar drying as acceptable technology for fish processing. PMID:25250381

  10. Development of solar drying model for selected Cambodian fish species.

    PubMed

    Hubackova, Anna; Kucerova, Iva; Chrun, Rithy; Chaloupkova, Petra; Banout, Jan

    2014-01-01

    A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6 °C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg · h(-1). Based on coefficient of determination (R(2)), chi-square (χ(2)) test, and root-mean-square error (RMSE), the most suitable models describing natural convection solar drying kinetics were Logarithmic model, Diffusion approximate model, and Two-term model for climbing perch and Nile tilapia, swamp eel and walking catfish and Channa fish, respectively. In case of electric oven drying, the Modified Page 1 model shows the best results for all investigated fish species except Channa fish where the two-term model is the best one. Sensory evaluation shows that most preferable fish is climbing perch, followed by Nile tilapia and walking catfish. This study brings new knowledge about drying kinetics of fresh water fish species in Cambodia and confirms the solar drying as acceptable technology for fish processing. PMID:25250381

  11. An assessment of oceanic seabird abundance and distribution off the southern Brazilian coast using observations obtained during deep-water fishing operations.

    PubMed

    Branco, J O; Fracasso, H A A; Pérez, J A A; Rodrigues-Filho, J L

    2014-08-01

    The use of discarded fish over baited hooks used in longline fishery, and fish caught in gillnets, as a food source for gulls, albatrosses and petrels has been intensively studied in northern and southern oceans. This study describes the occurrence and abundance of seabirds observed from 20 foreign vessels which operated during the period between July 2001 and May 2005, off the southeastern and southern Brazilian coast. A total of 353,557 seabirds were observed; comprising eight families and 28 species. The most abundant species was Procellaria conspicillata followed by Daption capense, Puffinus gravis, Thalassarche melanophrys and Oceanites oceanicus. Ten species of seabirds (392 individual birds) were incidentally captured in gillnets; and 122 birds (9 species) by longline hooks, with P. gravis, D. capense and Procellaria aequinoctialis having the largest capture rates. PMID:25627361

  12. Daughter Species Abundances in Comet C/2014 Q2 (Lovejoy)

    NASA Astrophysics Data System (ADS)

    McKay, Adam; Cochran, Anita; Dello Russo, Neil; Kelley, Michael

    2015-11-01

    We present analysis of high spectral resolution optical spectra of C/2014 Q2 (Lovejoy) acquired with the Tull Coude spectrometer on the 2.7-meter Harlan J. Smith Telescope at McDonald Observatory and the ARCES spectrometer mounted on the 3.5-meter Astrophysical Research Consortium Telescope at Apache Point Observatory. Both Tull Coude and ARCES provide high spectral resolution (R=30,000-60,000) and a large spectral range of approximately 3500-10000 Angstroms. We obtained two observation epochs, one in February 2015 at a heliocentric distance of 1.3 AU, and another in May 2015 at a heliocentric distance of 1.9 AU. Another epoch in late August 2015 at a heliocentric distance of 3.0 AU is scheduled. We will present production rates of the daughter species CN, C3, CH, C2, and NH2. We will also present H2O production rates derived from the [OI]6300 emission, as well as measurements of the flux ratio of the [OI]5577 Angstrom line to the sum of the [OI]6300 and [OI]6364 Angstrom lines (sometimes referred to as the oxygen line ratio). This ratio is indicative of the CO2 abundance of the comet. As we have observations at several heliocentric distances, we will examine how production rates and mixing ratios of the various species change with heliocentric distance. We will compare our oxygen line measurements to observations of CO2 made with Spitzer, as well as our other daughter species observations to those of candidate parent molecules made at IR wavelengths.

  13. Underappreciated species in ecology: "ugly fish" in the northwest Atlantic Ocean.

    PubMed

    Link, Jason S

    2007-10-01

    Species shifts and replacements are common in ecological studies. Observations thereof serve as the impetus for many ecological endeavors. Many of the species now known to dominate ecosystem functioning were largely ignored until studies of those underappreciated species elucidated their critical roles. Recognizing the potential importance of underappreciated species has implications for functional redundancies in ecosystems and should alter our approach to long-term monitoring. One example of an applied ecological system containing species shifts, underappreciated species, and potential changes in functional redundancies is the topic of fisheries. The demersal component of many fish communities usually consists of high-profile and commercially valuable species that are targets of fisheries, plus a diverse group of lesser known species that have minimal commercial value and focus. Yet ecologically these traditionally nontargeted species are often a major biomass sink in marine ecosystems and can also be critical in the functioning of bentho-demersal food webs. I examined the biomass trajectories of several species of skates, cottids, lophiids, anarhichadids, zooarcids, and similar species in the northeast U.S. Atlantic ecosystem to determine whether their relative abundance has changed across the past four decades. Distribution and stomach contents of these species were also evaluated over time to further elucidate the relative importance of these species. Landings of these underappreciated bentho-demersal fish were also examined in comparison to those species that historically have been commercially targeted. Of particular emphasis was the evaluation of evidence for sequential stock depletion and the ramifications for functional redundancy for this ecosystem. Results indicate that some of these fish species are now the dominant piscivores, benthivores, and scavengers in this ecosystem. These formerly under-studied species generally have either maintained a

  14. Abundance changes and habitat availability drive species' responses to climate change

    NASA Astrophysics Data System (ADS)

    Mair, Louise; Hill, Jane K.; Fox, Richard; Botham, Marc; Brereton, Tom; Thomas, Chris D.

    2014-02-01

    There is little consensus as to why there is so much variation in the rates at which different species' geographic ranges expand in response to climate warming. Here we show that the relative importance of species' abundance trends and habitat availability for British butterfly species vary over time. Species with high habitat availability expanded more rapidly from the 1970s to mid-1990s, when abundances were generally stable, whereas habitat availability effects were confined to the subset of species with stable abundances from the mid-1990s to 2009, when abundance trends were generally declining. This suggests that stable (or positive) abundance trends are a prerequisite for range expansion. Given that species' abundance trends vary over time for non-climatic as well as climatic reasons, assessment of abundance trends will help improve predictions of species' responses to climate change, and help us to understand the likely success of different conservation strategies for facilitating their expansions.

  15. Beyond the zebrafish: diverse fish species for modeling human disease

    PubMed Central

    Schartl, Manfred

    2014-01-01

    ABSTRACT In recent years, zebrafish, and to a lesser extent medaka, have become widely used small animal models for human diseases. These organisms have convincingly demonstrated the usefulness of fish for improving our understanding of the molecular and cellular mechanisms leading to pathological conditions, and for the development of new diagnostic and therapeutic tools. Despite the usefulness of zebrafish and medaka in the investigation of a wide spectrum of traits, there is evidence to suggest that other fish species could be better suited for more targeted questions. With the emergence of new, improved sequencing technologies that enable genomic resources to be generated with increasing efficiency and speed, the potential of non-mainstream fish species as disease models can now be explored. A key feature of these fish species is that the pathological condition that they model is often related to specific evolutionary adaptations. By exploring these adaptations, new disease-causing and disease-modifier genes might be identified; thus, diverse fish species could be exploited to better understand the complexity of disease processes. In addition, non-mainstream fish models could allow us to study the impact of environmental factors, as well as genetic variation, on complex disease phenotypes. This Review will discuss the opportunities that such fish models offer for current and future biomedical research. PMID:24271780

  16. Status of heavy metal residues in fish species of Pakistan.

    PubMed

    Hussain, Majid; Muhammad, Said; Malik, Riffat N; Khan, Muhammad U; Farooq, Umar

    2014-01-01

    In this review, we evaluate and summarize the available data that addresses the levels of HM that exist in aquatic species, mainly fish, of Pakistan. Data on this topic were collected from the literature of the last two decades (1990-2012). Results revealed that the highest number (>50%) of studies addressing HM-contaminated fish have occurred in the Punjab province, followed by the Sindh and Khyber Pakhtunkhwa provinces. Our review disclosed that the HM concentrations in Pakistani fish species varied considerably with location. Generally, the level of HM residues detected in fish species had the following descending order: Fe>Zn>Pb>Cd>Hg>Ni>Cu>Ag>Cr>Mn>As. Fish samples collected from the Kabul River near the Nowshera district, Stretch of Ravi River, Indus River near Mainwali district, and Arabian Sea at Karachi revealed extremely high HM concentrations (range: 0.34-8,381.30 jlg/g), compared to other fresh water bodies, such as the Llyold Barrage, Guddu Barrage, Jinnah Barrage, and Chashma Barrage (0.01-2.13 jlg/g). As a reference point, we also reviewed selected data on HM fish residues that exist in countries that neighbor Pakistan. With the exception of fish collected in India, the majority of fish analyzed for HM residues in neighboring countries displayed lower residues than did fish from Pakistan. We concluded from reviewing the available published data that the most probable sources for the HM contaminants found in Pakistani water and fish were release of domestic sewage, agricultural runoff, and industrial effluents. We strongly recommend that action be taken to better control the discharges of unregulated waste that enters the Pakistani aquatic environment, with the intent to mitigate any continuing future damage to the aquatic ecosystem. We also recommend intensifying research programs that address the toxicity of HM to the aquatic environment, so that a better understanding of metal effects on fish can be achieved that will lead to a sustainable

  17. Identifying across-system sources of variation in a generalist freshwater fish: Correlates of total and size-specific abundance of yellow perch

    USGS Publications Warehouse

    Carey, M.P.; Mather, M. E.

    2009-01-01

    Variation in fish abundance across systems presents a challenge to our understanding of fish populations because it limits our ability to predict and transfer basic ecological principles to applied problems. Yellow perch (Perca flavescens) is an ideal species for exploring environmental and biotic correlates across system because it is widely distributed and physiologically tolerant. In 16 small, adjacent systems that span a wide range of environmental and biotic conditions, yellow perch were sampled with a standard suite of gear. Water quality, morphometry, vegetation, invertebrates and fish communities were concurrently measured. Multimodel inference was used to prioritise regressors for the entire yellow perch sample and three size groups (35-80, 81-180, ???181 mm TL). Across systems, pH and fish richness were identified as the key drivers of yellow perch abundance. At very low pH (4.8) had many other species and few yellow perch. Similar patterns for pH and fish community were observed for the two largest-size classes. Negative interactions were observed between the medium- and large-sized yellow perch and between the largest and smallest yellow perch, although interspecific interactions were weaker than expected. This examination of variability for an indicator species and its component-size classes provides ecological understanding that can help frame the larger-scale sampling programs needed for the conservation of freshwater fish. ?? 2008 Blackwell Munksgaard.

  18. Effects of Fishing and Regional Species Pool on the Functional Diversity of Fish Communities

    PubMed Central

    Martins, Gustavo M.; Arenas, Francisco; Neto, Ana I.; Jenkins, Stuart R.

    2012-01-01

    The potential population and community level impacts of fishing have received considerable attention, but little is known about how fishing influences communities’ functional diversity at regional scales. We examined how estimates of functional diversity differed among 25 regions of variable richness and investigated the functional consequences of removing species targeted by commercial fisheries. Our study shows that fishing leads to substantial losses in functional diversity. The magnitude of such loss was, however, reduced in the more speciose regions. Moreover, the removal of commercially targeted species caused a much larger reduction in functional diversity than expected by random species deletions, which was a consequence of the selective nature of fishing for particular species traits. Results suggest that functional redundancy is spatially variable, that richer biotas provide some degree of insurance against the impact of fishing on communities’ functional diversity and that fishing predominantly selects for particular species traits. Understanding how fishing impacts community functional diversity is key to predict its effects for biodiversity as well as ecosystem functioning. PMID:22952950

  19. Effects of fishing and regional species pool on the functional diversity of fish communities.

    PubMed

    Martins, Gustavo M; Arenas, Francisco; Neto, Ana I; Jenkins, Stuart R

    2012-01-01

    The potential population and community level impacts of fishing have received considerable attention, but little is known about how fishing influences communities' functional diversity at regional scales. We examined how estimates of functional diversity differed among 25 regions of variable richness and investigated the functional consequences of removing species targeted by commercial fisheries. Our study shows that fishing leads to substantial losses in functional diversity. The magnitude of such loss was, however, reduced in the more speciose regions. Moreover, the removal of commercially targeted species caused a much larger reduction in functional diversity than expected by random species deletions, which was a consequence of the selective nature of fishing for particular species traits. Results suggest that functional redundancy is spatially variable, that richer biotas provide some degree of insurance against the impact of fishing on communities' functional diversity and that fishing predominantly selects for particular species traits. Understanding how fishing impacts community functional diversity is key to predict its effects for biodiversity as well as ecosystem functioning. PMID:22952950

  20. Commonly Rare and Rarely Common: Comparing Population Abundance of Invasive and Native Aquatic Species

    PubMed Central

    Hansen, Gretchen J. A.; Vander Zanden, M. Jake; Blum, Michael J.; Clayton, Murray K.; Hain, Ernie F.; Hauxwell, Jennifer; Izzo, Marit; Kornis, Matthew S.; McIntyre, Peter B.; Mikulyuk, Alison; Nilsson, Erika; Olden, Julian D.; Papeş, Monica; Sharma, Sapna

    2013-01-01

    Invasive species are leading drivers of environmental change. Their impacts are often linked to their population size, but surprisingly little is known about how frequently they achieve high abundances. A nearly universal pattern in ecology is that species are rare in most locations and abundant in a few, generating right-skewed abundance distributions. Here, we use abundance data from over 24,000 populations of 17 invasive and 104 native aquatic species to test whether invasive species differ from native counterparts in statistical patterns of abundance across multiple sites. Invasive species on average reached significantly higher densities than native species and exhibited significantly higher variance. However, invasive and native species did not differ in terms of coefficient of variation, skewness, or kurtosis. Abundance distributions of all species were highly right skewed (skewness>0), meaning both invasive and native species occurred at low densities in most locations where they were present. The average abundance of invasive and native species was 6% and 2%, respectively, of the maximum abundance observed within a taxonomic group. The biological significance of the differences between invasive and native species depends on species-specific relationships between abundance and impact. Recognition of cross-site heterogeneity in population densities brings a new dimension to invasive species management, and may help to refine optimal prevention, containment, control, and eradication strategies. PMID:24194883

  1. Commonly rare and rarely common: comparing population abundance of invasive and native aquatic species.

    PubMed

    Hansen, Gretchen J A; Vander Zanden, M Jake; Blum, Michael J; Clayton, Murray K; Hain, Ernie F; Hauxwell, Jennifer; Izzo, Marit; Kornis, Matthew S; McIntyre, Peter B; Mikulyuk, Alison; Nilsson, Erika; Olden, Julian D; Papeş, Monica; Sharma, Sapna

    2013-01-01

    Invasive species are leading drivers of environmental change. Their impacts are often linked to their population size, but surprisingly little is known about how frequently they achieve high abundances. A nearly universal pattern in ecology is that species are rare in most locations and abundant in a few, generating right-skewed abundance distributions. Here, we use abundance data from over 24,000 populations of 17 invasive and 104 native aquatic species to test whether invasive species differ from native counterparts in statistical patterns of abundance across multiple sites. Invasive species on average reached significantly higher densities than native species and exhibited significantly higher variance. However, invasive and native species did not differ in terms of coefficient of variation, skewness, or kurtosis. Abundance distributions of all species were highly right skewed (skewness>0), meaning both invasive and native species occurred at low densities in most locations where they were present. The average abundance of invasive and native species was 6% and 2%, respectively, of the maximum abundance observed within a taxonomic group. The biological significance of the differences between invasive and native species depends on species-specific relationships between abundance and impact. Recognition of cross-site heterogeneity in population densities brings a new dimension to invasive species management, and may help to refine optimal prevention, containment, control, and eradication strategies. PMID:24194883

  2. Hierarchical faunal filters: An approach to assessing effects of habitat and nonnative species on native fishes

    USGS Publications Warehouse

    Quist, M.C.; Rahel, F.J.; Hubert, W.A.

    2005-01-01

    Understanding factors related to the occurrence of species across multiple spatial and temporal scales is critical to the conservation and management of native fishes, especially for those species at the edge of their natural distribution. We used the concept of hierarchical faunal filters to provide a framework for investigating the influence of habitat characteristics and normative piscivores on the occurrence of 10 native fishes in streams of the North Platte River watershed in Wyoming. Three faunal filters were developed for each species: (i) large-scale biogeographic, (ii) local abiotic, and (iii) biotic. The large-scale biogeographic filter, composed of elevation and stream-size thresholds, was used to determine the boundaries within which each species might be expected to occur. Then, a local abiotic filter (i.e., habitat associations), developed using binary logistic-regression analysis, estimated the probability of occurrence of each species from features such as maximum depth, substrate composition, submergent aquatic vegetation, woody debris, and channel morphology (e.g., amount of pool habitat). Lastly, a biotic faunal filter was developed using binary logistic regression to estimate the probability of occurrence of each species relative to the abundance of nonnative piscivores in a reach. Conceptualising fish assemblages within a framework of hierarchical faunal filters is simple and logical, helps direct conservation and management activities, and provides important information on the ecology of fishes in the western Great Plains of North America. ?? Blackwell Munksgaard, 2004.

  3. RELATIONSHIPS OF ALIEN PLANT SPECIES ABUNDANCE TO RIPARIAN VEGETATION, ENVIRONMENT, AND DISTURBANCE

    EPA Science Inventory

    Riparian ecosystems are often invaded by alien species. We evaluated vegetation, environment, and disturbance conditions and their interrelationships with alien species abundance along reaches of 29 streams in eastern Oregon, USA. Using flexible-BETA clustering, indicator species...

  4. Plant Trait-Species Abundance Relationships Vary with Environmental Properties in Subtropical Forests in Eastern China

    PubMed Central

    Yan, En-Rong; Yang, Xiao-Dong; Chang, Scott X.; Wang, Xi-Hua

    2013-01-01

    Understanding how plant trait-species abundance relationships change with a range of single and multivariate environmental properties is crucial for explaining species abundance and rarity. In this study, the abundance of 94 woody plant species was examined and related to 15 plant leaf and wood traits at both local and landscape scales involving 31 plots in subtropical forests in eastern China. Further, plant trait-species abundance relationships were related to a range of single and multivariate (PCA axes) environmental properties such as air humidity, soil moisture content, soil temperature, soil pH, and soil organic matter, nitrogen (N) and phosphorus (P) contents. At the landscape scale, plant maximum height, and twig and stem wood densities were positively correlated, whereas mean leaf area (MLA), leaf N concentration (LN), and total leaf area per twig size (TLA) were negatively correlated with species abundance. At the plot scale, plant maximum height, leaf and twig dry matter contents, twig and stem wood densities were positively correlated, but MLA, specific leaf area, LN, leaf P concentration and TLA were negatively correlated with species abundance. Plant trait-species abundance relationships shifted over the range of seven single environmental properties and along multivariate environmental axes in a similar way. In conclusion, strong relationships between plant traits and species abundance existed among and within communities. Significant shifts in plant trait-species abundance relationships in a range of environmental properties suggest strong environmental filtering processes that influence species abundance and rarity in the studied subtropical forests. PMID:23560114

  5. Plant trait-species abundance relationships vary with environmental properties in subtropical forests in eastern china.

    PubMed

    Yan, En-Rong; Yang, Xiao-Dong; Chang, Scott X; Wang, Xi-Hua

    2013-01-01

    Understanding how plant trait-species abundance relationships change with a range of single and multivariate environmental properties is crucial for explaining species abundance and rarity. In this study, the abundance of 94 woody plant species was examined and related to 15 plant leaf and wood traits at both local and landscape scales involving 31 plots in subtropical forests in eastern China. Further, plant trait-species abundance relationships were related to a range of single and multivariate (PCA axes) environmental properties such as air humidity, soil moisture content, soil temperature, soil pH, and soil organic matter, nitrogen (N) and phosphorus (P) contents. At the landscape scale, plant maximum height, and twig and stem wood densities were positively correlated, whereas mean leaf area (MLA), leaf N concentration (LN), and total leaf area per twig size (TLA) were negatively correlated with species abundance. At the plot scale, plant maximum height, leaf and twig dry matter contents, twig and stem wood densities were positively correlated, but MLA, specific leaf area, LN, leaf P concentration and TLA were negatively correlated with species abundance. Plant trait-species abundance relationships shifted over the range of seven single environmental properties and along multivariate environmental axes in a similar way. In conclusion, strong relationships between plant traits and species abundance existed among and within communities. Significant shifts in plant trait-species abundance relationships in a range of environmental properties suggest strong environmental filtering processes that influence species abundance and rarity in the studied subtropical forests. PMID:23560114

  6. Gimme shelter: The importance of crevices to some fish species inhabiting a deeper-water rocky outcrop in Southern California

    USGS Publications Warehouse

    Love, M.S.; Schroeder, D.M.; Lenarz, B.; Cochrane, G.R.

    2006-01-01

    Federal law governing fisheries management recognizes the role habitat plays in structuring fish assemblages and achieving sustainable fisheries. However, in most instances it is not known which aspects of habitat are important to the lives of fish species. In 2004, we examined the importance of sheltering sites (crevices) to fishes living along low ledges in deeper waters off Anacapa Island, southern California. We found that patterns of fish-habitat relationships varied among the eight most abundant species. Three species, bocaccio (Sebastes paucispinis), vermilion (S. miniatus), and flag (S. rubrivinctus) rockfishes, had densities one to three orders of magnitude greater in the deep crevice habitat compared to low relief rock or shallow crevice habitats. Density and mean size of the two most abundant fishes, halfbanded (S. semicinctus) and squarespot (S. hopkinsi) rockfishes, generally increased as complexity of rock habitat increased. Not all species had the highest densities in deep crevice habitat. Greenspotted rockfish (S. chlorostictus) and blackeye goby (Rhinogobiops nicholsii) showed no significant difference in density among rock habitats. Pink seaperch (Zalembius rosaceus) were absent in the deep crevice habitat and abundant only in low relief rock habitats. Our study implies that it is not sufficient to distinguish only between soft and hard bottom types when using habitat to guide fisheries management strategies. Finer-scale investigations of fish-habitat relationships, paired with habitat mapping and groundtruthing, aid in the design and positioning of Marine Park Areas (MPAs) and are necessary to facilitate understanding of how a particular MPA may contribute to fisheries management.

  7. Aggregation and species coexistence of ectoparasites of marine fishes.

    PubMed

    Morand, S; Poulin, R; Rohde, K; Hayward, C

    1999-05-01

    Interspecific interaction may lead to species exclusion but there are several ways in which species can coexist. One way is by reducing the overall intensity of competition via aggregated utilisation of fragmented resources. Known as the 'aggregation model of coexistence', this system assumes saturation and an equilibrium number of species per community. In this study we tested the effects of interspecific aggregation on the level of intraspecific aggregation among ectoparasites of marine fishes (36 communities of gill and head ectoparasite species). If parasite species are distributed in a way that interspecific aggregation is reduced relative to intraspecific aggregation then species coexistence is facilitated. We found a positive relationship between parasite species richness and fish body size, controlling for host phylogeny. A positive relationship between infracommunity species richness and total parasite species richness was also found, providing no evidence for saturation. This result supports the view that infracommunities of parasites are not saturated by local parasite residents. The observed lack of saturation implies that we are far from a full exploitation of the fish resource by parasites. Ectoparasites were aggregated at both population and species levels. However, only half of the ectoparasite communities were dominated by negative interspecific aggregation. We found that infracommunity parasite species richness was positively correlated with the level of intraspecific aggregation versus interspecific aggregation. This means that intraspecific aggregation increases compared with interspecific aggregation when total parasite species richness increases, controlling fish size and phylogeny. This supports one assumption of the 'aggregation model of coexistence', which predicts that interspecific interactions are reduced relative to intraspecific interactions, facilitating species coexistence. PMID:10404260

  8. Can Citizen Science Survey Non-indigenous Fish Species in the Eastern Mediterranean Sea?

    NASA Astrophysics Data System (ADS)

    Bodilis, P.; Louisy, P.; Draman, M.; Arceo, H. O.; Francour, P.

    2014-01-01

    Engaging non-scientists to survey ecosystems, a process known as citizen science has been adopted worldwide. For the first time, this was applied to monitor fish assemblages in the Kas Peninsula, Turkey, an area known for its important Lessepsian fish populations. For 3 years (2004, 2007 and 2010), fish assemblages were surveyed using underwater visual census by transect method. A total of 29 species was observed, seven of which were Lessepsian species. Results show a significant increase in the Lessepsian species over the study period. In 2004, they represented 34 % of the total abundance, increasing to >61 % in 2010. Differences were observed in the progression of populations between two invasive herbivores, Siganus rivulatus and Siganus luridus (Siganidae), and two native herbivores, Sparisoma cretense (Scaridae) and Sarpa salpa (Sparidae). The siganids were recorded each year in all sites, whereas S. cretense was regularly observed in fewer numbers, while S. salpa was rarely censused. Abundance of Siganus spp. increased threefold in 6 years while abundances of S. cretense and S. salpa remained stable. S. rivulatus was the most abundant among the four species. Its competitive superiority may be due to its greater adaptability to fluctuating environmental conditions and biological traits, e.g. rapid growth, earlier sexual maturity, high fecundity. Because siganids are herbivorous, their presence can strongly impact algal ecosystems. It is then important to follow their spreading at a large scale, but this can be challenging due to the limited number of scientists. Adopting citizen science can thus be a useful strategy to monitor the spread of invasive species in the Mediterranean.

  9. Diel and distributional abundance patterns of fish embryos and larvae in the lower Columbia and Deschutes rivers

    USGS Publications Warehouse

    Gadomski, D.M.; Barfoot, C.A.

    1998-01-01

    Diel and distributional abundance patterns of free embryos and larvae of fishes in the lower Columbia River Basin were investigated. Ichthyoplankton samples were collected in 1993 during day and night in the main-channel and a backwater of the lower Columbia River, and in a tributary, the Deschutes River. Fish embryos and larvae collected in the main-channel Columbia River were primarily (85.6%) of native taxa (peamouth Mylocheilus caurinus, northern squawfish Ptychocheilus oregonensis, suckers Catostomus spp., and sculpins Cottus spp.), with two introduced species (American shad Alosa sapidissima and common carp Cyprinus carpio) comprising a smaller percentage of the catch (13.3%). Similarly, in the Deschutes River native taxa [lampreys (Petromyzontidae), minnows (Cyprinidae), and suckers Catostomus spp.] dominated collections (99.5% of the catch). In contrast, 83.5% of embryos and larvae in the Columbia River backwater were of introduced taxa [American shad, common carp, and sunfishes (Centrarchidae)]. In all locations, all dominant taxa except sculpins were collected in significantly greater proportions at night. Taxon-specific differences in proportions of embryos and larvae collected at night can in some instances be related to life history styles. In the main-channel Columbia River, northern squawfish and peamouth were strongly nocturnal and high proportions still had yolksacs, suggesting that they had recently hatched and were drifting downriver to rearing areas. In contrast, sculpin abundances were similar during day and night, and sculpins mostly had depleted yolksacs, indicating sculpins were feeding and rearing in offshore limnetic habitats. Taxon-specific diel abundance patterns and their causes must be considered when designing effective sampling programs for fish embryos and larvae.

  10. [On the Features of Embryonic Cleavage in Diverse Fish Species].

    PubMed

    Desnitskiy, A G

    2015-01-01

    Literature on the earliest steps of fish embryogenesis (including a number of "non-model" species) has been considered. The main attention has been paid to the loss of cleavage division synchrony and the first latitudinal cleavage furrow. In teleostean embryos, the features of their meroblastic cleavage are not rigidly associated with egg size. The midblastula transition (in a form clearly enough) occurs in some chondrostean and teleostean fishes, but it has not been detected in the representatives of sarcopterygian and chondrichthyan fishes. PMID:26859966

  11. Genetic assessment of ornamental fish species from North East India.

    PubMed

    Dhar, Bishal; Ghosh, Sankar Kumar

    2015-01-25

    Ornamental fishes are traded with multiple names from various parts around the world, including North East India. Most are collected from the wild, due to lack of species-specific culture or breeding, and therefore, such unmanaged collection of the wild and endemic species could lead to severe threats to biodiversity. Despite many regulatory policies, trade of threatened species, including the IUCN listed species have been largely uncontrolled, due to species identification problems arising from the utilization of multiple trade names. So, the development of species-specific DNA marker is indispensable where DNA Barcoding is proved to be helpful in species identification. Here, we investigated, through DNA Barcoding and morphological assessment, the identification of 128 ornamental fish specimens exported from NE India from different exporters. The generated sequences were subjected to similarity match in BOLD-IDS as well as BLASTN, and analysed using MEGA5.2 for species identification through Neighbour-Joining (NJ) clustering, and K2P distance based approach. The analysis revealed straightforward identification of 84 specimens into 35 species, while 44 specimens were difficult to distinguish based on CO1 barcode alone. However, these cases were resolved through morphology, NJ and distanced based method and found to be belonging to 16 species. Among the 51 identified species, 14 species represented multiple trade names; 17 species belonged to threatened category. Species-level identification through DNA Barcoding along with traditional morphotaxonomy reflects its efficacy in regulating ornamental fish trade and therefore, appeals for their conservation in nature. The use of trade names rather than the zoological name created the passage for trafficking of the threatened species and demands immediate attention for sustaining wildlife conservation. PMID:25447914

  12. Use of RAMAS to estimate ecological risk: Two fish species case studies

    SciTech Connect

    Ferson, S.; Akcakaya, R.; Ginzburg, L.; Krause, M. )

    1991-02-01

    RAMAS, (Risk Analysis Management Alternative System), a microcomputer simulation package for stochastic age-structured population models, was used to assess the population-level ecological risks associated with anthropogenic mortality in two species of fish. RAMAS facilitated comparison of the effects of fishing and entrainment/impingement mortality on Hudson River striped bass populations. The highest likely mortality levels associated with power generation did not yield increases in risk of overall population decline as large as did the pressure from sport fishing alone (33 in. limit, 5/day). Qualitative differences associated with the life stages affected by these industries account for most of the variation observed. Simulations performed under a range of assumptions about density-dependent parameters for the striped bass population gave similar conclusions. However, strengthening density dependence decreased the probability of quasi-extinction slightly. Density-dependent stochastic demographic modeling of a bluegill population in selenium (Se) affected power plant cooling lake in North Carolina revealed intrinsic cycling of population abundance. This cycling increases the risk that population abundances will fall to low levels in natural as well as anthropogenically impacted populations. The dynamics of bluegills affected by Se contrasts sharply with that of the undisturbed fish. Continuation of the Se discharge will most likely result in the suppression of the affected bluegill population. The bluegill population, however, could recover to natural levels of abundance within two or three generations if Se discharge were significantly curtailed. 9 refs., 29 figs., 7 tabs.

  13. 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. PMID:26691084

  14. Trophic interactions between native and introduced fish species in a littoral fish community.

    PubMed

    Monroy, M; Maceda-Veiga, A; Caiola, N; De Sostoa, A

    2014-11-01

    The trophic interactions between 15 native and two introduced fish species, silverside Odontesthes bonariensis and rainbow trout Oncorhynchus mykiss, collected in a major fishery area at Lake Titicaca were explored by integrating traditional ecological knowledge and stable-isotope analyses (SIA). SIA suggested the existence of six trophic groups in this fish community based on δ(13)C and δ(15)N signatures. This was supported by ecological evidence illustrating marked spatial segregation between groups, but a similar trophic level for most of the native groups. Based on Bayesian ellipse analyses, niche overlap appeared to occur between small O. bonariensis (<90 mm) and benthopelagic native species (31.6%), and between the native pelagic killifish Orestias ispi and large O. bonariensis (39%) or O. mykiss (19.7%). In addition, Bayesian mixing models suggested that O. ispi and epipelagic species are likely to be the main prey items for the two introduced fish species. This study reveals a trophic link between native and introduced fish species, and demonstrates the utility of combining both SIA and traditional ecological knowledge to understand trophic relationships between fish species with similar feeding habits. PMID:25263642

  15. Modelling community dynamics based on species-level abundance models from detection/nondetection data

    USGS Publications Warehouse

    Yamaura, Yuichi; Royle, J. Andrew; Kuboi, Kouji; Tada, Tsuneo; Ikeno, Susumu; Makino, Shun'ichi

    2011-01-01

    1. In large-scale field surveys, a binary recording of each species' detection or nondetection has been increasingly adopted for its simplicity and low cost. Because of the importance of abundance in many studies, it is desirable to obtain inferences about abundance at species-, functional group-, and community-levels from such binary data. 2. We developed a novel hierarchical multi-species abundance model based on species-level detection/nondetection data. The model accounts for the existence of undetected species, and variability in abundance and detectability among species. Species-level detection/nondetection is linked to species- level abundance via a detection model that accommodates the expectation that probability of detection (at least one individuals is detected) increases with local abundance of the species. We applied this model to a 9-year dataset composed of the detection/nondetection of forest birds, at a single post-fire site (from 7 to 15 years after fire) in a montane area of central Japan. The model allocated undetected species into one of the predefined functional groups by assuming a prior distribution on individual group membership. 3. The results suggest that 15–20 species were missed in each year, and that species richness of communities and functional groups did not change with post-fire forest succession. Overall abundance of birds and abundance of functional groups tended to increase over time, although only in the winter, while decreases in detectabilities were observed in several species. 4. Synthesis and applications. Understanding and prediction of large-scale biodiversity dynamics partly hinge on how we can use data effectively. Our hierarchical model for detection/nondetection data estimates abundance in space/time at species-, functional group-, and community-levels while accounting for undetected individuals and species. It also permits comparison of multiple communities by many types of abundance-based diversity and similarity

  16. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Southwest): Amphipods

    SciTech Connect

    Grosse, D.J.; Pauley, G.B.

    1989-01-01

    Species profiles are literature summaries of the taxonomy, morphology, distribution, life history, and environmental requirements of coastal aquatic species. They are prepared to assist in environmental impact assessment. Amphipods are ubiquitous in distribution, but are most abundant in estuarine areas and other high nutrient areas. Hyperiidea are the third most abundant coastal marine crustacean zooplankton, following copepods and euphausiids. Benthic Gammaridea are an invaluable food source for many economically important fish and invertebrate species. Habitat preference and behavior of the major amphipod groups is highly variable. Intertidal California amphipods overlap the distribution of common genera of other regions around the world. Amphipoda are reported to be indicators of heavily polluted areas. They are considered the most efficient of all scavengers on the sea bottom and in shoreline areas. 66 refs., 5 figs.

  17. [Fatty acids in different edible fish species from Mexico].

    PubMed

    Castro González, María Isabel; Rodríguez, Ana Gabriela Maafs; Galindo Gómez, Carlos

    2013-12-01

    Different biotic and abiotic factors determine the fatty acid (FA) composition of fish tissues and organs. This information is useful for humans due to the fact that fish consumption is associated with health benefits. The aim of the present study was to identify the variation in the concentration of fatty acids, according to different factors, among ten edible marine fish species in Mexico, collected from June to December 2009 in the largest fish market in Mexico City: Euthynnus alletteratus, Sciaenops ocellatus, Bairdiella chrysoura, Sphyraena guachancho, Symphurus elongatus, Istiophorus platypterus, Ophichthus rex, Eugerres plumieri, Eucinostomus entomelas and Oreochromrnis mossambicus. Lipid content was gravimetrically quantified, the fatty acids were determined using a gas chromatograph and the results were statistically analyzed. Total lipid content ranged from 0.93 to 1.95 g/100 g in E. entomelas and O. urolepis hornorum, respectively. E. alletteratus, B. chrysoura, S. elongatus, I. platypterus, O. rex and E. plumieri presented the following order in FA concentration: Polyunsaturated FA (PUFA)>Saturated FA (SFA)>Monounsaturated FA (MUFA). S. ocellatus, S. guachancho and E. entomelas presented SFA>PUFA>MUFA; and only O. mossambicus presented SFA>MUFA>PUFA. O. mossambicus had the highest concentration (mg/100 g) of SFA (559.40) and MUFA (442.60), while B. chrysoura presented the highest content (mg/100 g) of PUFA (663.03), n-3 PUFA (514.03), EPA+DHA (506.10) and n-6 PUFA (145.80). Biotic and abiotic factors of the analyzed fish significantly influenced their FA concentration. Subtropical species presented 42.1% more EPA+DHA than tropical specie. Values presented here will vary according to the changes in the ecosystem and characteristics of each fish species, however the information generated in the present study is useful for improving fish consumption recommendations. PMID:24432548

  18. Severe Inbreeding and Small Effective Number of Breeders in a Formerly Abundant Marine Fish

    PubMed Central

    O'Leary, Shannon J.; Hice, Lyndie A.; Feldheim, Kevin A.; Frisk, Michael G.; McElroy, Anne E.; Fast, Mark D.; Chapman, Demian D.

    2013-01-01

    In contrast to freshwater fish it is presumed that marine fish are unlikely to spawn with close relatives due to the dilution effect of large breeding populations and their propensity for movement and reproductive mixing. Inbreeding is therefore not typically a focal concern of marine fish management. We measured the effective number of breeders in 6 New York estuaries for winter flounder (Pseudopleuronectes americanus), a formerly abundant fish, using 11 microsatellite markers (6–56 alleles per locus). The effective number of breeders for 1–2 years was remarkably small, with point estimates ranging from 65–289 individuals. Excess homozygosity was detected at 10 loci in all bays (FIS = 0.169–0.283) and individuals exhibited high average internal relatedness (IR; mean = 0.226). These both indicate that inbreeding is very common in all bays, after testing for and ruling out alternative explanations such as technical and sampling artifacts. This study demonstrates that even historically common marine fish can be prone to inbreeding, a factor that should be considered in fisheries management and conservation plans. PMID:23762473

  19. Severe inbreeding and small effective number of breeders in a formerly abundant marine fish.

    PubMed

    O'Leary, Shannon J; Hice, Lyndie A; Feldheim, Kevin A; Frisk, Michael G; McElroy, Anne E; Fast, Mark D; Chapman, Demian D

    2013-01-01

    In contrast to freshwater fish it is presumed that marine fish are unlikely to spawn with close relatives due to the dilution effect of large breeding populations and their propensity for movement and reproductive mixing. Inbreeding is therefore not typically a focal concern of marine fish management. We measured the effective number of breeders in 6 New York estuaries for winter flounder (Pseudopleuronectes americanus), a formerly abundant fish, using 11 microsatellite markers (6-56 alleles per locus). The effective number of breeders for 1-2 years was remarkably small, with point estimates ranging from 65-289 individuals. Excess homozygosity was detected at 10 loci in all bays (FIS = 0.169-0.283) and individuals exhibited high average internal relatedness (IR; mean = 0.226). These both indicate that inbreeding is very common in all bays, after testing for and ruling out alternative explanations such as technical and sampling artifacts. This study demonstrates that even historically common marine fish can be prone to inbreeding, a factor that should be considered in fisheries management and conservation plans. PMID:23762473

  20. RELATIVE ABUNDANCE OF TOTAL AND METHYL MERCURY IN 1994-5 LAKE MICHIGAN FORAGE FISH

    EPA Science Inventory

    As part of the Lake Michigan Mass Balance Project, forage fish samples were collected in 1994-5 from three regions within Lake Michigan: Saugatuck, Michigan and Port Washington and Sturgeon Bay, Wisconsin by the USGS Great Lakes Science Center in Ann Arbor, Michigan. Species of ...

  1. Ecomorphological correlates of twenty dominant fish species of Amazonian floodplain lakes.

    PubMed

    Siqueira-Souza, F K; Bayer, C; Caldas, W H; Cardoso, D C; Yamamoto, K C; Freitas, C E C

    2016-07-11

    Fishes inhabiting Amazonian floodplain lakes exhibits a great variety of body shape, which was a key advantage to colonize the several habitats that compose these areas adjacent to the large Amazon rivers. In this paper, we did an ecomorphological analysis of twenty abundant species, sampled in May and August 2011, into two floodplain lakes of the lower stretch of the Solimões River. The analysis detected differences among species, which could be probably associated with swimming ability and habitat use preferences. PMID:27409231

  2. Distribution and abundance of fishes and invertebrates in Gulf of Mexico estuaries. Volume 1. Data summaries. Final report, 1985-1991

    SciTech Connect

    Nelson, D.M.; Monaco, M.E.; Williams, C.D.; Czapla, T.E.; Pattillo, M.E.

    1992-09-01

    The report presents information on the spatial and temporal distribution, and relative abundance of 44 fish and invertebrate species in 31 estuaries along the Gulf of Mexico coast of Florida, Alabama, Mississippi, Louisiana, and Texas. Its purpose is to disseminate data developed in the National Oceanic and Atmospheric Administration's (NOAA) Estuarine Living Marine Resources (ELMR) Program. The presence, distribution, and relative abundance of each species and the time period it uses each estuary are the primary data compiled. The report combines information presented in earlier reports for nine estuaries in Texas, 13 estuaries in Florida and Alabama, and nine estuaries in Louisiana and Mississippi. However, several species have been added, and the graphic depiction of relative abundance has been improved.

  3. Metal speciation in sediment and their bioaccumulation in fish species of three urban rivers in Bangladesh.

    PubMed

    Islam, Md Saiful; Ahmed, Md Kawser; Raknuzzaman, Mohammad; Habibullah-Al-Mamun, Md; Masunaga, Shigeki

    2015-01-01

    Six trace metals (chromium [Cr], nickel [Ni], copper [Cu], arsenic [As], cadmium [Cd] and lead [Pb]) were measured in sediments and soft tissues of three commonly consumed fish species (Channa punctatus, Heteropneustes fossilis, and Trichogaster fasciata) collected from three urban rivers around Dhaka City, Bangladesh. The abundance of total metals in sediments varied in the decreasing order of Cr > Ni > Pb > Cu > As > Cd. Sequential extraction tests showed that the studied metals were predominantly associated with the residual fraction followed by the organically bound phase. The range of metal concentration in fish species were as follows: Cr (0.75-4.8), Ni (0.14-3.1), Cu (1.1-7.2), As (0.091-0.53), Cd (0.008-0.13), and Pb (0.052-2.7 mg/kg wet weight [ww]). The rank of biota-sediment accumulation factor for fish species were in the descending order of Cu > As > Pb > Ni > Cr > Cd. Metal concentrations in fish exceeded the international permissible standards suggesting that these species are not safe for human consumption. PMID:25213477

  4. Hankin and Reeves' Approach to Estimating Fish Abundance in Small Streams : Limitations and Potential Options.

    SciTech Connect

    Thompson, William L.

    2000-11-01

    Hankin and Reeves' (1988) approach to estimating fish abundance in small streams has been applied in stream-fish studies across North America. However, as with any method of population estimation, there are important assumptions that must be met for estimates to be minimally biased and reasonably precise. Consequently, I investigated effects of various levels of departure from these assumptions via simulation based on results from an example application in Hankin and Reeves (1988) and a spatially clustered population. Coverage of 95% confidence intervals averaged about 5% less than nominal when removal estimates equaled true numbers within sampling units, but averaged 62% - 86% less than nominal when they did not, with the exception where detection probabilities of individuals were >0.85 and constant across sampling units (95% confidence interval coverage = 90%). True total abundances averaged far (20% - 41%) below the lower confidence limit when not included within intervals, which implies large negative bias. Further, average coefficient of variation was about 1.5 times higher when removal estimates did not equal true numbers within sampling units (C{bar V} = 0.27 [SE = 0.0004]) than when they did (C{bar V} = 0.19 [SE = 0.0002]). A potential modification to Hankin and Reeves' approach is to include environmental covariates that affect detection rates of fish into the removal model or other mark-recapture model. A potential alternative is to use snorkeling in combination with line transect sampling to estimate fish densities. Regardless of the method of population estimation, a pilot study should be conducted to validate the enumeration method, which requires a known (or nearly so) population of fish to serve as a benchmark to evaluate bias and precision of population estimates.

  5. Accounting for Incomplete Species Detection in Fish Community Monitoring

    SciTech Connect

    McManamay, Ryan A; Orth, Dr. Donald J; Jager, Yetta

    2013-01-01

    Riverine fish assemblages are heterogeneous and very difficult to characterize with a one-size-fits-all approach to sampling. Furthermore, detecting changes in fish assemblages over time requires accounting for variation in sampling designs. We present a modeling approach that permits heterogeneous sampling by accounting for site and sampling covariates (including method) in a model-based framework for estimation (versus a sampling-based framework). We snorkeled during three surveys and electrofished during a single survey in suite of delineated habitats stratified by reach types. We developed single-species occupancy models to determine covariates influencing patch occupancy and species detection probabilities whereas community occupancy models estimated species richness in light of incomplete detections. For most species, information-theoretic criteria showed higher support for models that included patch size and reach as covariates of occupancy. In addition, models including patch size and sampling method as covariates of detection probabilities also had higher support. Detection probability estimates for snorkeling surveys were higher for larger non-benthic species whereas electrofishing was more effective at detecting smaller benthic species. The number of sites and sampling occasions required to accurately estimate occupancy varied among fish species. For rare benthic species, our results suggested that higher number of occasions, and especially the addition of electrofishing, may be required to improve detection probabilities and obtain accurate occupancy estimates. Community models suggested that richness was 41% higher than the number of species actually observed and the addition of an electrofishing survey increased estimated richness by 13%. These results can be useful to future fish assemblage monitoring efforts by informing sampling designs, such as site selection (e.g. stratifying based on patch size) and determining effort required (e.g. number of

  6. Some organochlorine pesticide residues in fish species in Konya, Turkey.

    PubMed

    Kalyoncu, Leyla; Agca, Ihsan; Aktumsek, Abdurrahman

    2009-02-01

    The levels of organochlorine pesticides were measured in 18 fish species from Konya markets, Turkey. These species were selected on the basis of their importance to local human fish consumption. The extracted residues were analyzed on a micro capillary gas chromatograph equipped with an electron capture detector. Total 14 different organochlorine pesticides were determined. These residues were detected in all fish species, except in trout, horse mackerel and bonito. DDT and its metabolites and HCH were the predominant contaminants in fish muscles. The mean concentrations of summation operator DDT were in the range between 0.0008 and 0.0828 microg g(-1). DDT was the predominant residue in Sparus aurata. Detectable levels of HCH, aldrin, and heptachlor were found in most samples. However, dieldrin, endrin, beta endosulfan, p-p' DDT, and p-p' DDD were not found in Salmo trutta. The mean of endrin ranged from 0.0040 microg g(-1) (Triglia lineate) to 0.0326 microg g(-1) (Trachurus trachurus). These results give no indication of important health risks associated with the consumption of these fishes in Konya markets. PMID:19103455

  7. Patterns of fish use and piscivore abundance within a reconnected saltmarsh impoundment in the northern Indian River Lagoon, Florida

    USGS Publications Warehouse

    Stevens, Philip W.; Montague, C.L.; Sulak, K.J.

    2006-01-01

    Nearly all saltmarshes in east-central, Florida were impounded for mosquito control during the 1960s. The majority of these marshes have since been reconnected to the estuary by culverts, providing an opportunity to effectively measure exchange of aquatic organisms. A multi-gear approach was used monthly to simultaneously estimate fish standing stock (cast net), fish exchange with the estuary (culvert traps), and piscivore abundance (gill nets and bird counts) to document patterns of fish use in a reconnected saltmarsh impoundment. Changes in saltmarsh fish abundance, and exchange of fish with the estuary reflected the seasonal pattern of marsh flooding in the northern Indian River Lagoon system. During a 6-month period of marsh flooding, resident fish had continuous access to the marsh surface. Large piscivorous fish regularly entered the impoundment via creeks and ditches to prey upon small resident fish, and piscivorous birds aggregated following major fish movements to the marsh surface or to deep habitats. As water levels receded in winter, saltmarsh fish concentrated into deep habitats and emigration to the estuary ensued (200% greater biomass left the impoundment than entered). Fish abundance and community structure along the estuary shoreline (although fringed with marsh vegetation) were not analogous to marsh creeks and ditches. Perimeter ditches provided deep-water habitat for large estuarine predators, and shallow creeks served as an alternative habitat for resident fish when the marsh surface was dry. Use of the impoundment as nursery by transients was limited to Mugil cephalus Linnaeus, but large juvenile and adult piscivorous fish used the impoundment for feeding. In conclusion, the saltmarsh impoundment was a feeding site for piscivorous fish and birds, and functioned as a net exporter of forage fish to adjacent estuarine waters. ?? Springer 2006.

  8. Abundance, Composition, and Sinking Rates of Fish Fecal Pellets in the Santa Barbara Channel

    PubMed Central

    Saba, Grace K.; Steinberg, Deborah K.

    2012-01-01

    Rapidly sinking fecal pellets are an important component of the vertical flux of particulate organic matter (POM) from the surface to the ocean's interior; however, few studies have examined the role fish play in this export. We determined abundance, size, prey composition, particulate organic carbon/nitrogen (POC/PON), and sinking rates of fecal pellets produced by a forage fish, likely the northern anchovy, in the Santa Barbara Channel. Pellet abundance ranged from 0.1–5.9 pellets m−3. POC and PON contents averaged 21.7 µg C pellet−1 and 2.7 µg N pellet−1. The sinking rate averaged 787 m d−1; thus pellets produced at the surface would reach the benthos (~500 m) in <1 day. Estimated downward flux of fish fecal POC reached a maximum of 251 mg C m−2 d−1. This is equal to or exceeds previous measurements of sediment trap POM flux, and thus may transport significant amounts of repackaged surface material to depth. PMID:23056908

  9. Relations between fish abundances, summer temperatures, and forest harvest in a northern Minnesota stream system from 1997 to 2007

    USGS Publications Warehouse

    Merten, Eric C.; Hemstad, Nathaniel A.; Eggert, L.S.; Johnson, L.B.; Kolka, R.K.; Newman, Raymond M.; Vondracek, Bruce C.

    2015-01-01

    Short-term effects of forest harvest on fish habitat have been well documented, including sediment inputs, leaf litter reductions, and stream warming. However, few studies have considered changes in local climate when examining postlogging changes in fish communities. To address this need, we examined fish abundances between 1997 and 2007 in a basin in a northern hardwood forest. Streams in the basin were subjected to experimental riparian forest harvest in fall 1997. We noted a significant decrease for fish index of biotic integrity and abundance of Salvelinus fontinalis and Phoxinus eos over the study period. However, for P. eos and Culaea inconstans, the temporal patterns in abundances were related more to summer air temperatures than to fine sediment or spring precipitation when examined using multiple regressions. Univariate regressions suggested that summer air temperatures influenced temporal patterns in fish communities more than fine sediment or spring precipitation.

  10. Relations between fish abundances, summer temperatures, and forest harvest in a northern Minnesota stream system from 1997 to 2007

    USGS Publications Warehouse

    Merten, Eric C.; Hemstad, Nathaniel A.; Eggert, S.L.; Johnson, L.B.; Kolka, Randall K.; Newman, Raymond M.; Vondracek, Bruce C.

    2010-01-01

    Short-term effects of forest harvest on fish habitat have been well documented, including sediment inputs, leaf litter reductions, and stream warming. However, few studies have considered changes in local climate when examining postlogging changes in fish communities. To address this need, we examined fish abundances between 1997 and 2007 in a basin in a northern hardwood forest. Streams in the basin were subjected to experimental riparian forest harvest in fall 1997. We noted a significant decrease for fish index of biotic integrity and abundance of Salvelinus fontinalis and Phoxinus eos over the study period. However, for P. eos and Culaea inconstans, the temporal patterns in abundances were related more to summer air temperatures than to fine sediment or spring precipitation when examined using multiple regressions. Univariate regressions suggested that summer air temperatures influenced temporal patterns in fish communities more than fine sediment or spring precipitation.

  11. Fish and wildlife species as sentinels of environmental endocrine disruption

    USGS Publications Warehouse

    Sheffield, S.R.; Matter, J.M.; Rattner, B.A.; Guiney, P.D.

    1998-01-01

    This chapter provides an overview of the history and criteria for use of captive and free-ranging fish and wildlife (amphibians, reptiles, birds, and mammals) species as sentinels of potential environmental endocrine disruption. Biochemical, behavioral, physiological, immunological, genetic, reproductive, developmental, and ecological correlates of endocrine disruption in these sentinels are presented and reviewed. In addition, data needs to promote better use of sentinel species in the assessment of endocrine disruption are discussed.

  12. The IUCN Red List of Threatened Species: an assessment of coral reef fishes in the US Pacific Islands

    NASA Astrophysics Data System (ADS)

    Zgliczynski, B. J.; Williams, I. D.; Schroeder, R. E.; Nadon, M. O.; Richards, B. L.; Sandin, S. A.

    2013-09-01

    Widespread declines among many coral reef fisheries have led scientists and managers to become increasingly concerned over the extinction risk facing some species. To aid in assessing the extinction risks facing coral reef fishes, large-scale censuses of the abundance and distribution of individual species are critically important. We use fisheries-independent data collected as part of the NOAA Pacific Reef Assessment and Monitoring Program from 2000 to 2009 to describe the range and density across the US Pacific of coral reef fishes included on The International Union for the Conservation of Nature's (IUCN) 2011 Red List of Threatened Species. Forty-five species, including sharks, rays, groupers, humphead wrasse ( Cheilinus undulatus), and bumphead parrotfish ( Bolbometopon muricatum), included on the IUCN List, were recorded in the US Pacific Islands. Most species were generally rare in the US Pacific with the exception of a few species, principally small groupers and reef sharks. The greatest diversity and densities of IUCN-listed fishes were recorded at remote and uninhabited islands of the Pacific Remote Island Areas; in general, lower densities were observed at reefs of inhabited islands. Our findings complement IUCN assessment efforts, emphasize the efficacy of large-scale assessment and monitoring efforts in providing quantitative data on reef fish assemblages, and highlight the importance of protecting populations at remote and uninhabited islands where some species included on the IUCN Red List of Threatened Species can be observed in abundance.

  13. Use of Droplet Digital PCR for Estimation of Fish Abundance and Biomass in Environmental DNA Surveys

    PubMed Central

    Doi, Hideyuki; Uchii, Kimiko; Takahara, Teruhiko; Matsuhashi, Saeko; Yamanaka, Hiroki; Minamoto, Toshifumi

    2015-01-01

    An environmental DNA (eDNA) analysis method has been recently developed to estimate the distribution of aquatic animals by quantifying the number of target DNA copies with quantitative real-time PCR (qPCR). A new quantitative PCR technology, droplet digital PCR (ddPCR), partitions PCR reactions into thousands of droplets and detects the amplification in each droplet, thereby allowing direct quantification of target DNA. We evaluated the quantification accuracy of qPCR and ddPCR to estimate species abundance and biomass by using eDNA in mesocosm experiments involving different numbers of common carp. We found that ddPCR quantified the concentration of carp eDNA along with carp abundance and biomass more accurately than qPCR, especially at low eDNA concentrations. In addition, errors in the analysis were smaller in ddPCR than in qPCR. Thus, ddPCR is better suited to measure eDNA concentration in water, and it provides more accurate results for the abundance and biomass of the target species than qPCR. We also found that the relationship between carp abundance and eDNA concentration was stronger than that between biomass and eDNA by using both ddPCR and qPCR; this suggests that abundance can be better estimated by the analysis of eDNA for species with fewer variations in body mass. PMID:25799582

  14. Spatial distribution and species composition of small pelagic fishes in the Gulf of California.

    PubMed

    Lanz, Edgar; Nevárez-Martínez, Manuel O; López-Martínez, Juana; Dworak, Juan A

    2008-06-01

    Traditional regionalization methods in fisheries based on provinces or major fishing areas, includes large and arbitrary grids in which basic statistics or inferences on distribution or abundance are made. We describe a method for regionalization and analysis of fishing activities for small pelagic fisheries in the Gulf of California based on spatial patterns of landing and catch data in a Geographic Information System (GIS) environment. A fisheries database from logbooks with spatial attributes from October 2002 to June 2007 was analyzed. Landings and catching data were transformed to a Weighted Region Index (WRI) by using fuzzy logic operators. The WRI revealed fishing action centers characterized by areas with the highest WRI values, and a hierarchy for the relative importance of the regions was established. Guaymas, Desemboque de Caborca, Isla Patos, and Bahia San Rafael they were the most prominent ones. An analysis of the relative frequency of species composition showed that the Pacific sardine had an over 80 % abundance in the midriff islands, and remained as the most important in the upper gulf regions, while in the central part of the gulf, relative abundances of Pacific sardine and Northern anchovy were more balanced. Relative abundance of mackerel was significantly larger around Isla Patos than in any other place. Guaymas had the largest relative composition of Northern anchovy and the lowest values for Pacific sardine. Desemboque de Caborca showed the largest homogeneity in species relative composition. It is important to highlight that this results come from in situ data, while the results previously reported come from landing statistics by port. Therefore, the present method acknowledges the spatial differences of species by regions, additional to the traditional time series analysis. PMID:19256429

  15. THREATENED AND ENDANGERED FRESHWATER FISH AND MUSSEL SPECIES RICHNESS

    EPA Science Inventory

    These data represent predicted current distributions of all US listed Threatened and Endangered freshwater fish and freshwater mussels in the Middle-Atlantic region. The data are available for both 8-digit HUCs and EMAP hexagons and represent total species counts for each spatia...

  16. Effects of thermal discharges on the distribution and abundance of adult fishes in the Savannah River and selected tributaries: Annual report, November 1984-August 1985

    SciTech Connect

    Paller, M.H.; Saul, B.M.

    1986-01-01

    A study of the juvenile and adult fish community in streams draining the SRP and in the Savannah River in the area of the SRP was conducted between September 1984 and September 1985. The major objectives were to examine the abundance and distribution of fishes near the Savannah River Plant in relation to thermal discharges into the river, creeks, and floodplain swamps and to determine the rate of impingement of adult and juvenile fishes on the intake screens at the SRP pumphouses. The most abundant fishes (excluding minnows) taken by electrofishing were the redbreast sunfish (41.6%), spotted sucker (8.8%), spotted sunfish (8.2%), largemouth bass (5.7%), bluegill (5.6%), and American eel (5.4%). The most abundant fishes taken by hoop netting were the flat bullhead (38.0%), channel catfish (11.9%), bluegill (9.4%), white catfish (7.9%), black crappie (6.5%), and redbreast sunfish (5.5%). Dominant species in the intake canals were the bluegill, redbreast sunfish, and black crappie. Dominant species in the nonthermal river were the redbreast sunfish, spotted sunfish, spotted sucker, largemouth bass, channel catfish, white catfish, and flat bullhead. Dominant species in the nonthermal creeks were fairly similar to river species except that the catfishes were not as well represented. The thermal river and creek habitats differed from the nonthermal habitats in having higher percentages (although often lower numbers) of channel catfish, white catfish, largemouth bass, and coastal shiner and a lower percentage of flat bullhead.

  17. Impacts of variation in planktivorous fish on abundance of daphnids: A simulation model of the Lake Mendota food web: Chapter 20

    USGS Publications Warehouse

    Luecke, Chris; Lunte, Cynthia C.; Wright, Russell A.; Robertson, Dale M.; McLain, Ann S.

    1992-01-01

    Previous chapters in this volume have outlined the goals of the Lake Mendota food web manipulation study (Rudstam et al., Ch. 12) and have reported on variations in phytoplankton and zooplankton abundances during the past 15 years (Lathrop and Carpenter, Ch. 7 and 8). Because of the long time scales inherent in such a lake management manipulation, it became imperative to attempt to predict how the lake would respond to changes in planktivorous fish abundance over time scales of several decades. We know from the past 15 years of study (Lathrop and Carpenter, Ch. 7 and 8; Magnuson and Lathrop, Ch. 11) that substantial variation of planktivorous fish, zooplankton, and phytoplankton abundances can occur the lake. Given the current stocking of piscivores, we have the potential to substantially modify the abundance of planktivorous fish and possibly shift the assemblages of phytoplankton and zooplankton beyond the ranges of those which occurred previously. In this chapter we describe the construction and use of a simulation model designed to examine how variation in plantivore abundance might impact zooplankton biomass and species composition.

  18. Trawls and cooling-water intakes as estuarine fish sampling tools: Comparisons of catch composition, trends in relative abundance, and length selectivity

    NASA Astrophysics Data System (ADS)

    Greenwood, M. F. D.

    2008-01-01

    Fish populations in estuaries are often monitored with traditional sampling gears such as trawls. Trawling is relatively expensive and may be hindered by environmental conditions such as tides and substrates. Power station cooling-water intake screens have been effectively used as estuarine fish sampling devices for many years, but very few quantitative comparisons of intake fish-catch characteristics with samples from other collection methods have been made. Fish collected at the cooling-water intake of a large power station in the lower Forth estuary, UK, were more similar in assemblage composition to fish caught by nearby pelagic trawling than to fish caught by Agassiz (demersal) trawling, mostly because the intake and pelagic-trawl catches were largely composed of clupeids ( Sprattus sprattus and Clupea harengus). The intake catch was typified by pelagic, demersal, and benthic species, however, and was less variable than the catches made by the two trawls. Monthly trends in relative abundance correlated reasonably well between the intake and trawl samples. Fish collected at the intake tended to be significantly smaller than those collected by trawling, which was probably attributable to the intake's smaller mesh size. The study highlighted the utility of a cooling-water intake as an efficient, low-cost fish sampling device, which should be considered as an alternative to trawling as the cost of the latter increases into the future.

  19. Feeding ecology of indigenous and non-indigenous fish species within the family Sphyraenidae.

    PubMed

    Kalogirou, S; Mittermayer, F; Pihl, L; Wennhage, H

    2012-06-01

    The feeding ecology of two common indigenous (Sphyraena viridensis and Sphyraena sphyraena) and one abundant non-indigenous sphyraenid species, Sphyraena chrysotaenia, of Indo-Pacific Ocean origin, was investigated in an area of the eastern Mediterranean Sea. The stomach contents of 738 individuals of varying size, collected during the period December 2008 to August 2009, were examined. The dietary analyses revealed that all three species were specialized piscivores with a diet consisting of >90% fish, both by number and mass. Concurrent sampling of the fish assemblage made it possible to calculate selectivity as well as diet breadth and overlap of these strict piscivores. Even though several prey species were found in the stomachs of the three predators examined, selectivity towards Atherina boyeri was highly significant. For all species examined, >70% of the diet by mass was made up by three indigenous species of commercial value: Spicara smaris, Boops boops and A. boyeri. Diet breadth and size of prey increased with increasing body size for all predators. With increased body size, the diet overlap between indigenous and non-indigenous species decreased. This could be attributed to increased diet breadth and the specific life-history characteristics of indigenous species developing into larger individuals. During winter, the condition factor of the non-indigenous species was significantly lower than that of the indigenous, indicating that winter conditions in the Mediterranean Sea may limit its further expansion north and westward. With this study, the gap in knowledge of the feeding preferences of the most abundant piscivorous species found in coastal areas of the study region is filled. Additionally, the results indicate that non-indigenous species familial affiliation to indigenous ones does not facilitate invasion success. PMID:22650432

  20. Abundances of northwestern salamander larvae in montane lakes with and without fish, Mount Rainier National Park, Washington

    USGS Publications Warehouse

    Larson, Gary L.; Hoffman, Robert L.

    2002-01-01

    In Mount Rainier National Park, the northwestern salamander usually inhabits relatively large and deep lakes and ponds (average size = 0.3 ha; average depth > 2 m) that contain flocculent, organic bottom sediments and abundant coarse wood. Prior to 1970, salmonids were introduced into many of the park's lakes and ponds that were typical habitat of the northwestern salamander. The objective of this study was to compare, in lakes and ponds with suitable habitat characteristics for northwestern salamanders, the observed abundances of larvae in takes and ponds with and without these introduced salmonids. Day surveys of 61 lakes were conducted between 1993 and 1999. Fish were limited to takes and ponds deeper than 2 in. For the 48 lakes and ponds deeper than 2 in (i.e., 25 fishless lakes and 23 fish lakes), the mean and median observed abundances of northwestern salamander larvae in fishless lakes and ponds was significantly greater than the mean and median observed abundances of larvae in lakes and ponds with fish. Northwestern salamander larvae were not observed in 11 fish lakes. These lakes were similar in median elevation, surface area, and maximum depth to the fishless lakes. The 12 fish lakes with observed larvae were significantly lower in median elevation, larger in median surface area, and deeper in median maximum depth than the fishless lakes. Low to null observed abundances of northwestern salamander larvae in lakes and ponds with fish were attributed to a combination of fish predation of larvae and changes in larval behavior.

  1. Hydroacoustic estimates of abundance and spatial distribution of pelagic prey fishes in western Lake Superior

    USGS Publications Warehouse

    Mason, Doran M.; Johnson, Timothy B.; Harvey, Chris J.; Kitchell, James F.; Schram, Stephen T.; Bronte, Charles R.; Hoff, MIchael H.; Lozano, Stephen J.; Trebitz, Anett S.; Schreiner, Donald R.; Lamon, E. Conrad; Hrabik, Thomas R.

    2005-01-01

    Lake herring (Coregonus artedi) and rainbow smelt (Osmerus mordax) are a valuable prey resource for the recovering lake trout (Salvelinus namaycush) in Lake Superior. However, prey biomass may be insufficient to support the current predator demand. In August 1997, we assessed the abundance and spatial distribution of pelagic coregonines and rainbow smelt in western Lake Superior by combining a 120 kHz split beam acoustics system with midwater trawls. Coregonines comprised the majority of the midwater trawl catches and the length distributions for trawl caught fish coincided with estimated sizes of acoustic targets. Overall mean pelagic prey fish biomass was 15.56 kg ha−1 with the greatest fish biomass occurring in the Apostle Islands region (27.98 kg ha−1), followed by the Duluth Minnesota region (20.22 kg ha−1), and with the lowest biomass occurring in the open waters of western Lake Superior (9.46 kg ha−1). Biomass estimates from hydroacoustics were typically 2–134 times greater than estimates derived from spring bottom trawl surveys. Prey fish biomass for Lake Superior is about order of magnitude less than acoustic estimates for Lakes Michigan and Ontario. Discrepancies observed between bioenergetics-based estimates of predator consumption of coregonines and earlier coregonine biomass estimates may be accounted for by our hydroacoustic estimates.

  2. Liquid chromatographic determination of oxytetracycline in edible fish fillets from six species of fish

    USGS Publications Warehouse

    Meinertz, J.R.; Stehly, G.R.; Gingerich, W.H.

    1998-01-01

    The approved use of oxytetracycline (OTC) in U.S. Aquaculture is limited to specific diseases in salmonids and channel catfish. OTC may also be effective in controlling diseases in other fish species important to public aquaculture, but before approved use of OTC can be augmented, an analytical method for determining OTC in fillet tissue from multiple species of fish will be required to support residue depletion studies. The objective of this study was to develop and validate a liquid chromatographic (LC) method that is accurate, precise, and sensitive for OTC in edible fillets from multiple species of fish. Homogenized fillet tissues from walleye, Atlantic salmon, striped bass, white sturgeon, rainbow trout, and channel catfish were fortified with OTC at nominal concentrations of 10, 20, 100, 1000, and 5000 ng/g. In tissues fortified with OTC at 100, 1000, and 5000 ng/g, mean recoveries ranged from 83 to 90%, and relative standard deviations (RSDs) ranged from 0.9 to 5.8%. In all other tissues, mean recoveries ranged from 59 to 98%, and RSDs ranged from 3.3 to 20%. Method quantitation limits ranged from 6 to 22 ng/g for the 6 species. The LC parameters produced easily integratable OTC peaks without coelution of endogenous compounds. The method is accurate, precise, and sensitive for OTC in fillet tissue from 6 species of fish from 5 phylogenetically diverse groups.

  3. Increased natural mortality at low abundance can generate an Allee effect in a marine fish

    PubMed Central

    Kuparinen, Anna; Hutchings, Jeffrey A.

    2014-01-01

    Negative density-dependent regulation of population dynamics promotes population growth at low abundance and is therefore vital for recovery following depletion. Inversely, any process that reduces the compensatory density-dependence of population growth can negatively affect recovery. Here, we show that increased adult mortality at low abundance can reverse compensatory population dynamics into its opposite—a demographic Allee effect. Northwest Atlantic cod (Gadus morhua) stocks collapsed dramatically in the early 1990s and have since shown little sign of recovery. Many experienced dramatic increases in natural mortality, ostensibly attributable in some populations to increased predation by seals. Our findings show that increased natural mortality of a magnitude observed for overfished cod stocks has been more than sufficient to fundamentally alter the dynamics of density-dependent population regulation. The demographic Allee effect generated by these changes can slow down or even impede the recovery of depleted populations even in the absence of fishing. PMID:26064531

  4. Increased natural mortality at low abundance can generate an Allee effect in a marine fish.

    PubMed

    Kuparinen, Anna; Hutchings, Jeffrey A

    2014-10-01

    Negative density-dependent regulation of population dynamics promotes population growth at low abundance and is therefore vital for recovery following depletion. Inversely, any process that reduces the compensatory density-dependence of population growth can negatively affect recovery. Here, we show that increased adult mortality at low abundance can reverse compensatory population dynamics into its opposite-a demographic Allee effect. Northwest Atlantic cod (Gadus morhua) stocks collapsed dramatically in the early 1990s and have since shown little sign of recovery. Many experienced dramatic increases in natural mortality, ostensibly attributable in some populations to increased predation by seals. Our findings show that increased natural mortality of a magnitude observed for overfished cod stocks has been more than sufficient to fundamentally alter the dynamics of density-dependent population regulation. The demographic Allee effect generated by these changes can slow down or even impede the recovery of depleted populations even in the absence of fishing. PMID:26064531

  5. Influence of species, size and relative abundance on the outcomes of competitive interactions between brook trout and juvenile coho salmon

    USGS Publications Warehouse

    Thornton, Emily J; Duda, Jeff; Quinn, Thomas P

    2016-01-01

    Resource competition between animals is influenced by a number of factors including the species, size and relative abundance of competing individuals. Stream-dwelling animals often experience variably available food resources, and some employ territorial behaviors to increase their access to food. We investigated the factors that affect dominance between resident, non-native brook trout and recolonizing juvenile coho salmon in the Elwha River, WA, USA, to see if brook trout are likely to disrupt coho salmon recolonization via interference competition. During dyadic laboratory feeding trials, we hypothesized that fish size, not species, would determine which individuals consumed the most food items, and that species would have no effect. We found that species, not size, played a significant role in dominance; coho salmon won 95% of trials, even when only 52% the length of their brook trout competitors. As the pairs of competing fish spent more time together during a trial sequence, coho salmon began to consume more food, and brook trout began to lose more, suggesting that the results of early trials influenced fish performance later. In group trials, we hypothesized that group composition and species would not influence fish foraging success. In single species groups, coho salmon consumed more than brook trout, but the ranges overlapped. Brook trout consumption remained constant through all treatments, but coho salmon consumed more food in treatments with fewer coho salmon, suggesting that coho salmon experienced more intra- than inter-specific competition and that brook trout do not pose a substantial challenge. Based on our results, we think it is unlikely that competition from brook trout will disrupt Elwha River recolonization by coho salmon.

  6. Bed disturbance via foraging fish increases bedload transport during subsequent high flows and is controlled by fish size and species

    NASA Astrophysics Data System (ADS)

    Pledger, A. G.; Rice, S. P.; Millett, J.

    2016-01-01

    % greater. An interesting implication of these results, given the abundance and widespread distribution of foraging fish, is that numerous fish species belonging to a variety of functional groups may be acting as zoogeomorphic agents in rivers, directly affecting bed material conditions and sediment transport fluxes in proportion to their body size and feeding traits.

  7. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Southwest)

    SciTech Connect

    Rackowski, J.P.; Pikitch, E.K. . Dept. of Fisheries and Wildlife; Washington Univ., Seattle, WA . Fisheries Research Inst.)

    1989-08-01

    Species profiles are literature summaries of taxonomy, morphology, range, growth characteristics, ecology, life history, and commercial importance of coastal species. Pacific sanddab, Citharichthys sordidus, and speckled sanddab, Citharichthys stigmaeus, are common along the California coast from the intertidal zone to depths of 306 m. Pacific sanddabs spawn from July to September and speckled sanddabs, from April to September. Eggs and larvae are common throughout the range of the species. Average life span is 8--10 years in Pacific sanddabs and 3--4 years in speckled sanddabs. Females of both species live longer than males. Female Pacific sanddabs attain sexual maturity at age 3 and female speckled sanddabs, at age 2. Postlarvae feed on zooplankton; adults eat a variety of crustaceans and fish. Both species prefer sandy bottoms. The speckled sanddab was the most abundant species caught in trawl surveys off southern California. Commercial catch statistics lump both species under sanddabs''. Average annual landings, 1930--70, were 500,000 pounds and from 1971--86, landings rose to 900,000 pounds. Commercial fish buyers paid $0.37 per pound for sanddabs in April, 1987. 48 refs., 9 figs.

  8. From the Cover: Ecological community description using the food web, species abundance, and body size

    NASA Astrophysics Data System (ADS)

    Cohen, Joel E.; Jonsson, Tomas; Carpenter, Stephen R.

    2003-02-01

    Measuring the numerical abundance and average body size of individuals of each species in an ecological community's food web reveals new patterns and illuminates old ones. This approach is illustrated using data from the pelagic community of a small lake: Tuesday Lake, Michigan, United States. Body mass varies almost 12 orders of magnitude. Numerical abundance varies almost 10 orders of magnitude. Biomass abundance (average body mass times numerical abundance) varies only 5 orders of magnitude. A new food web graph, which plots species and trophic links in the plane spanned by body mass and numerical abundance, illustrates the nearly inverse relationship between body mass and numerical abundance, as well as the pattern of energy flow in the community. Species with small average body mass occur low in the food web of Tuesday Lake and are numerically abundant. Larger-bodied species occur higher in the food web and are numerically rarer. Average body size explains more of the variation in numerical abundance than does trophic height. The trivariate description of an ecological community by using the food web, average body sizes, and numerical abundance includes many well studied bivariate and univariate relationships based on subsets of these three variables. We are not aware of any single community for which all of these relationships have been analyzed simultaneously. Our approach demonstrates the connectedness of ecological patterns traditionally treated as independent. Moreover, knowing the food web gives new insight into the disputed form of the allometric relationship between body mass and abundance.

  9. Colony geometry and structural complexity of the endangered species Acropora cervicornis partly explains the structure of their associated fish assemblage.

    PubMed

    Agudo-Adriani, Esteban A; Cappelletto, Jose; Cavada-Blanco, Francoise; Croquer, Aldo

    2016-01-01

    In the past decade, significant efforts have been made to describe fish-habitat associations. However, most studies have oversimplified actual connections between fish assemblages and their habitats by using univariate correlations. The purpose of this study was to identify the features of habitat forming corals that facilitate and influences assemblages of associated species such as fishes. For this we developed three-dimensional models of colonies of Acropora cervicornis to estimate geometry (length and height), structural complexity (i.e., volume, density of branches, etc.) and biological features of the colonies (i.e., live coral tissue, algae). We then correlated these colony characteristics with the associated fish assemblage using multivariate analyses. We found that geometry and complexity were better predictors of the structure of fish community, compared to other variables such as percentage of live coral tissue or algae. Combined, the geometry of each colony explained 40% of the variability of the fish assemblage structure associated with this coral species; 61% of the abundance and 69% of fish richness, respectively. Our study shows that three-dimensional reconstructions of discrete colonies of Acropora cervicornis provides a useful description of the colonial structural complexity and may explain a great deal of the variance in the structure of the associated coral reef fish community. This demonstration of the strongly trait-dependent ecosystem role of this threatened species has important implications for restoration and conservation efforts. PMID:27069801

  10. Colony geometry and structural complexity of the endangered species Acropora cervicornis partly explains the structure of their associated fish assemblage

    PubMed Central

    Cappelletto, Jose; Cavada-Blanco, Francoise; Croquer, Aldo

    2016-01-01

    In the past decade, significant efforts have been made to describe fish-habitat associations. However, most studies have oversimplified actual connections between fish assemblages and their habitats by using univariate correlations. The purpose of this study was to identify the features of habitat forming corals that facilitate and influences assemblages of associated species such as fishes. For this we developed three-dimensional models of colonies of Acropora cervicornis to estimate geometry (length and height), structural complexity (i.e., volume, density of branches, etc.) and biological features of the colonies (i.e., live coral tissue, algae). We then correlated these colony characteristics with the associated fish assemblage using multivariate analyses. We found that geometry and complexity were better predictors of the structure of fish community, compared to other variables such as percentage of live coral tissue or algae. Combined, the geometry of each colony explained 40% of the variability of the fish assemblage structure associated with this coral species; 61% of the abundance and 69% of fish richness, respectively. Our study shows that three-dimensional reconstructions of discrete colonies of Acropora cervicornis provides a useful description of the colonial structural complexity and may explain a great deal of the variance in the structure of the associated coral reef fish community. This demonstration of the strongly trait-dependent ecosystem role of this threatened species has important implications for restoration and conservation efforts. PMID:27069801

  11. Random versus fixed-site sampling when monitoring relative abundance of fishes in headwater streams of the upper Colorado River basin

    USGS Publications Warehouse

    Quist, M.C.; Gerow, K.G.; Bower, M.R.; Hubert, W.A.

    2006-01-01

    Native fishes of the upper Colorado River basin (UCRB) have declined in distribution and abundance due to habitat degradation and interactions with normative fishes. Consequently, monitoring populations of both native and nonnative fishes is important for conservation of native species. We used data collected from Muddy Creek, Wyoming (2003-2004), to compare sample size estimates using a random and a fixed-site sampling design to monitor changes in catch per unit effort (CPUE) of native bluehead suckers Catostomus discobolus, flannelmouth suckers C. latipinnis, roundtail chub Gila robusta, and speckled dace Rhinichthys osculus, as well as nonnative creek chub Semotilus atromaculatus and white suckers C. commersonii. When one-pass backpack electrofishing was used, detection of 10% or 25% changes in CPUE (fish/100 m) at 60% statistical power required 50-1,000 randomly sampled reaches among species regardless of sampling design. However, use of a fixed-site sampling design with 25-50 reaches greatly enhanced the ability to detect changes in CPUE. The addition of seining did not appreciably reduce required effort. When detection of 25-50% changes in CPUE of native and nonnative fishes is acceptable, we recommend establishment of 25-50 fixed reaches sampled by one-pass electrofishing in Muddy Creek. Because Muddy Creek has habitat and fish assemblages characteristic of other headwater streams in the UCRB, our results are likely to apply to many other streams in the basin. ?? Copyright by the American Fisheries Society 2006.

  12. Regional Variation in Parasite Species Richness and Abundance in the Introduced Range of the Invasive Lionfish, Pterois volitans.

    PubMed

    Sellers, Andrew J; Ruiz, Gregory M; Leung, Brian; Torchin, Mark E

    2015-01-01

    Parasites can play an important role in biological invasions. While introduced species often lose parasites from their native range, they can also accumulate novel parasites in their new range. The accumulation of parasites by introduced species likely varies spatially, and more parasites may shift to new hosts where parasite diversity is high. Considering that parasitism and disease are generally more prevalent at lower latitudes, the accumulation of parasites by introduced hosts may be greater in tropical regions. The Indo-Pacific lionfish (Pterois volitans) has become widely distributed across the Western Atlantic. In this study, we compared parasitism across thirteen locations in four regions, spanning seventeen degrees of latitude in the lionfish's introduced range to examine potential spatial variation in parasitism. In addition, as an initial step to explore how indirect effects of parasitism might influence interactions between lionfish and ecologically similar native hosts, we also compared parasitism in lionfish and two co-occurring native fish species, the graysby grouper, Cephalopholis cruentata, and the lizardfish, Synodus intermedius, in the southernmost region, Panama. Our results show that accumulation of native parasites on lionfish varies across broad spatial scales, and that colonization by ectoparasites was highest in Panama, relative to the other study sites. Endoparasite richness and abundance, on the other hand, were highest in Belize where lionfish were infected by twice as many endoparasite species as lionfish in other regions. The prevalence of all but two parasite species infecting lionfish was below 25%, and we did not detect an association between parasite abundance and host condition, suggesting a limited direct effect of parasites on lionfish, even where parasitism was highest. Further, parasite species richness and abundance were significantly higher in both native fishes compared to lionfish, and parasite abundance was negatively

  13. Regional Variation in Parasite Species Richness and Abundance in the Introduced Range of the Invasive Lionfish, Pterois volitans

    PubMed Central

    2015-01-01

    Parasites can play an important role in biological invasions. While introduced species often lose parasites from their native range, they can also accumulate novel parasites in their new range. The accumulation of parasites by introduced species likely varies spatially, and more parasites may shift to new hosts where parasite diversity is high. Considering that parasitism and disease are generally more prevalent at lower latitudes, the accumulation of parasites by introduced hosts may be greater in tropical regions. The Indo-Pacific lionfish (Pterois volitans) has become widely distributed across the Western Atlantic. In this study, we compared parasitism across thirteen locations in four regions, spanning seventeen degrees of latitude in the lionfish's introduced range to examine potential spatial variation in parasitism. In addition, as an initial step to explore how indirect effects of parasitism might influence interactions between lionfish and ecologically similar native hosts, we also compared parasitism in lionfish and two co-occurring native fish species, the graysby grouper, Cephalopholis cruentata, and the lizardfish, Synodus intermedius, in the southernmost region, Panama. Our results show that accumulation of native parasites on lionfish varies across broad spatial scales, and that colonization by ectoparasites was highest in Panama, relative to the other study sites. Endoparasite richness and abundance, on the other hand, were highest in Belize where lionfish were infected by twice as many endoparasite species as lionfish in other regions. The prevalence of all but two parasite species infecting lionfish was below 25%, and we did not detect an association between parasite abundance and host condition, suggesting a limited direct effect of parasites on lionfish, even where parasitism was highest. Further, parasite species richness and abundance were significantly higher in both native fishes compared to lionfish, and parasite abundance was negatively

  14. The Importance of the Regional Species Pool, Ecological Species Traits and Local Habitat Conditions for the Colonization of Restored River Reaches by Fish

    PubMed Central

    Stoll, Stefan; Kail, Jochem; Lorenz, Armin W.; Sundermann, Andrea; Haase, Peter

    2014-01-01

    It is commonly assumed that the colonization of restored river reaches by fish depends on the regional species pools; however, quantifications of the relationship between the composition of the regional species pool and restoration outcome are lacking. We analyzed data from 18 German river restoration projects and adjacent river reaches constituting the regional species pools of the restored reaches. We found that the ability of statistical models to describe the fish assemblages established in the restored reaches was greater when these models were based on ‘biotic’ variables relating to the regional species pool and the ecological traits of species rather than on ‘abiotic’ variables relating to the hydromorphological habitat structure of the restored habitats and descriptors of the restoration projects. For species presence in restored reaches, ‘biotic’ variables explained 34% of variability, with the occurrence rate of a species in the regional species pool being the most important variable, while ’abiotic’ variables explained only the negligible amount of 2% of variability. For fish density in restored reaches, about twice the amount of variability was explained by ‘biotic’ (38%) compared to ‘abiotic’ (21%) variables, with species density in the regional species pool being most important. These results indicate that the colonization of restored river reaches by fish is largely determined by the assemblages in the surrounding species pool. Knowledge of species presence and abundance in the regional species pool can be used to estimate the likelihood of fish species becoming established in restored reaches. PMID:24404187

  15. Fish introductions reveal the temperature dependence of species interactions.

    PubMed

    Hein, Catherine L; Öhlund, Gunnar; Englund, Göran

    2014-01-22

    A major area of current research is to understand how climate change will impact species interactions and ultimately biodiversity. A variety of environmental conditions are rapidly changing owing to climate warming, and these conditions often affect both the strength and outcome of species interactions. We used fish distributions and replicated fish introductions to investigate environmental conditions influencing the coexistence of two fishes in Swedish lakes: brown trout (Salmo trutta) and pike (Esox lucius). A logistic regression model of brown trout and pike coexistence showed that these species coexist in large lakes (more than 4.5 km(2)), but not in small, warm lakes (annual air temperature more than 0.9-1.5°C). We then explored how climate change will alter coexistence by substituting climate scenarios for 2091-2100 into our model. The model predicts that brown trout will be extirpated from approximately half of the lakes where they presently coexist with pike and from nearly all 9100 lakes where pike are predicted to invade. Context dependency was critical for understanding pike-brown trout interactions, and, given the widespread occurrence of context-dependent species interactions, this aspect will probably be critical for accurately predicting climate impacts on biodiversity. PMID:24307673

  16. Fish introductions reveal the temperature dependence of species interactions

    PubMed Central

    Hein, Catherine L.; Öhlund, Gunnar; Englund, Göran

    2014-01-01

    A major area of current research is to understand how climate change will impact species interactions and ultimately biodiversity. A variety of environmental conditions are rapidly changing owing to climate warming, and these conditions often affect both the strength and outcome of species interactions. We used fish distributions and replicated fish introductions to investigate environmental conditions influencing the coexistence of two fishes in Swedish lakes: brown trout (Salmo trutta) and pike (Esox lucius). A logistic regression model of brown trout and pike coexistence showed that these species coexist in large lakes (more than 4.5 km2), but not in small, warm lakes (annual air temperature more than 0.9–1.5°C). We then explored how climate change will alter coexistence by substituting climate scenarios for 2091–2100 into our model. The model predicts that brown trout will be extirpated from approximately half of the lakes where they presently coexist with pike and from nearly all 9100 lakes where pike are predicted to invade. Context dependency was critical for understanding pike–brown trout interactions, and, given the widespread occurrence of context-dependent species interactions, this aspect will probably be critical for accurately predicting climate impacts on biodiversity. PMID:24307673

  17. The Shark Assemblage at French Frigate Shoals Atoll, Hawai‘i: Species Composition, Abundance and Habitat Use

    PubMed Central

    Dale, Jonathan J.; Stankus, Austin M.; Burns, Michael S.; Meyer, Carl G.

    2011-01-01

    Empirical data on the abundance and habitat preferences of coral reef top predators are needed to evaluate their ecological impacts and guide management decisions. We used longline surveys to quantify the shark assemblage at French Frigate Shoals (FFS) atoll from May to August 2009. Fishing effort consisted of 189 longline sets totaling 6,862 hook hours of soak time. A total of 221 sharks from 7 species were captured, among which Galapagos (Carcharhinus galapagensis, 36.2%), gray reef (Carcharhinus amblyrhynchos, 25.8%) and tiger (Galeocerdo cuvier, 20.4%) sharks were numerically dominant. A lack of blacktip reef sharks (Carcharhinus melanopterus) distinguished the FFS shark assemblage from those at many other atolls in the Indo-Pacific. Compared to prior underwater visual survey estimates, longline methods more accurately represented species abundance and composition for the majority of shark species. Sharks were significantly less abundant in the shallow lagoon than adjacent habitats. Recaptures of Galapagos sharks provided the first empirical estimate of population size for any Galapagos shark population. The overall recapture rate was 5.4%. Multiple closed population models were evaluated, with Chao Mh ranking best in model performance and yielding a population estimate of 668 sharks with 95% confidence intervals ranging from 289–1720. Low shark abundance in the shallow lagoon habitats suggests removal of a small number of sharks from the immediate vicinity of lagoonal islets may reduce short-term predation on endangered monk seal (Monachus schauinslandi) pups, but considerable fishing effort would be required to catch even a small number of sharks. Additional data on long-term movements and habitat use of sharks at FFS are required to better assess the likely ecological impacts of shark culling. PMID:21347321

  18. The shark assemblage at French Frigate Shoals atoll, Hawai'i: species composition, abundance and habitat use.

    PubMed

    Dale, Jonathan J; Stankus, Austin M; Burns, Michael S; Meyer, Carl G

    2011-01-01

    Empirical data on the abundance and habitat preferences of coral reef top predators are needed to evaluate their ecological impacts and guide management decisions. We used longline surveys to quantify the shark assemblage at French Frigate Shoals (FFS) atoll from May to August 2009. Fishing effort consisted of 189 longline sets totaling 6,862 hook hours of soak time. A total of 221 sharks from 7 species were captured, among which Galapagos (Carcharhinus galapagensis, 36.2%), gray reef (Carcharhinus amblyrhynchos, 25.8%) and tiger (Galeocerdo cuvier, 20.4%) sharks were numerically dominant. A lack of blacktip reef sharks (Carcharhinus melanopterus) distinguished the FFS shark assemblage from those at many other atolls in the Indo-Pacific. Compared to prior underwater visual survey estimates, longline methods more accurately represented species abundance and composition for the majority of shark species. Sharks were significantly less abundant in the shallow lagoon than adjacent habitats. Recaptures of Galapagos sharks provided the first empirical estimate of population size for any Galapagos shark population. The overall recapture rate was 5.4%. Multiple closed population models were evaluated, with Chao M(h) ranking best in model performance and yielding a population estimate of 668 sharks with 95% confidence intervals ranging from 289-1720. Low shark abundance in the shallow lagoon habitats suggests removal of a small number of sharks from the immediate vicinity of lagoonal islets may reduce short-term predation on endangered monk seal (Monachus schauinslandi) pups, but considerable fishing effort would be required to catch even a small number of sharks. Additional data on long-term movements and habitat use of sharks at FFS are required to better assess the likely ecological impacts of shark culling. PMID:21347321

  19. Estimating Abundances of Interacting Species Using Morphological Traits, Foraging Guilds, and Habitat

    PubMed Central

    Dorazio, Robert M.; Connor, Edward F.

    2014-01-01

    We developed a statistical model to estimate the abundances of potentially interacting species encountered while conducting point-count surveys at a set of ecologically relevant locations – as in a metacommunity of species. In the model we assume that abundances of species with similar traits (e.g., body size) are potentially correlated and that these correlations, when present, may exist among all species or only among functionally related species (such as members of the same foraging guild). We also assume that species-specific abundances vary among locations owing to systematic and stochastic sources of heterogeneity. For example, if abundances differ among locations due to differences in habitat, then measures of habitat may be included in the model as covariates. Naturally, the quantitative effects of these covariates are assumed to differ among species. Our model also accounts for the effects of detectability on the observed counts of each species. This aspect of the model is especially important for rare or uncommon species that may be difficult to detect in community-level surveys. Estimating the detectability of each species requires sampling locations to be surveyed repeatedly using different observers or different visits of a single observer. As an illustration, we fitted models to species-specific counts of birds obtained while sampling an avian community during the breeding season. In the analysis we examined whether species abundances appeared to be correlated due to similarities in morphological measures (body mass, beak length, tarsus length, wing length, tail length) and whether these correlations existed among all species or only among species of the same foraging guild. We also used the model to estimate the effects of forested area on species abundances and the effects of sound power output (as measured by body size) on species detection probabilities. PMID:24727898

  20. Estimating abundances of interacting species using morphological traits, foraging guilds, and habitat

    USGS Publications Warehouse

    Dorazio, Robert M.; Connor, Edward F.

    2014-01-01

    We developed a statistical model to estimate the abundances of potentially interacting species encountered while conducting point-count surveys at a set of ecologically relevant locations - as in a metacommunity of species. In the model we assume that abundances of species with similar traits (e.g., body size) are potentially correlated and that these correlations, when present, may exist among all species or only among functionally related species (such as members of the same foraging guild). We also assume that species-specific abundances vary among locations owing to systematic and stochastic sources of heterogeneity. For example, if abundances differ among locations due to differences in habitat, then measures of habitat may be included in the model as covariates. Naturally, the quantitative effects of these covariates are assumed to differ among species. Our model also accounts for the effects of detectability on the observed counts of each species. This aspect of the model is especially important for rare or uncommon species that may be difficult to detect in community-level surveys. Estimating the detectability of each species requires sampling locations to be surveyed repeatedly using different observers or different visits of a single observer. As an illustration, we fitted models to species-specific counts of birds obtained while sampling an avian community during the breeding season. In the analysis we examined whether species abundances appeared to be correlated due to similarities in morphological measures (body mass, beak length, tarsus length, wing length, tail length) and whether these correlations existed among all species or only among species of the same foraging guild. We also used the model to estimate the effects of forested area on species abundances and the effects of sound power output (as measured by body size) on species detection probabilities.

  1. Application of hydroacoustics to investigate the distribution, diel movement, and abundance of fish on Zhubi Reef, Nansha Islands, South China Sea

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Chen, Guobao; Chen, Zuozhi; Qiu, Yongsong; Xiong, Dan

    2016-01-01

    A combination of traditional fish sampling methods (hand-line and gill net) and modern hydroacoustic techniques were used to study fish community structure, distribution, and diel movements of fish on Zhubi Reef to enhance understanding of the ecosystem. We collected 126 individuals from 29 species, 20 genera, 17 families, three orders, and two classes using traditional gear. Perciforms were the dominant group in terms of species richness and biomass. The acoustic data indicated that very small (target strength [TS], dB) <-60 dB) and small (-60 dB≤TS<-45 dB) fish contributed the most to abundance and species richness on the coral reef, and that the proportion of medium-sized (-45 dB≤TS<-35 dB) and large-sized (-35 dB≤TS) fish increased gradually as depth increased. The single-target detection method revealed two distinct size classes during the day in the 12-16 and 16-20-m layers. One group consisted of very small-sized fish (TS<-60 dB) and the other consisted of medium and large-sized fish (TS>-55 dB). The number of single-target detections was significantly higher during the night than during the day (P<0.05). The singletarget TS frequency distribution during the day was significantly diff erent than during the night at depths of 4-8, 8-12, 12-16, and 16-20 m. Significant diff erences were observed among the 4-8, 8-12, 12-16, and 16-20-m-depth layers during day and night. Diel vertical movement was evidenced as fish began to spread and move upward just before sunset and began to assemble and descend shortly (15 min) after sunrise.

  2. Application of hydroacoustics to investigate the distribution, diel movement, and abundance of fish on Zhubi Reef, Nansha Islands, South China Sea

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Chen, Guobao; Chen, Zuozhi; Qiu, Yongsong; Xiong, Dan

    2016-09-01

    A combination of traditional fish sampling methods (hand-line and gill net) and modern hydroacoustic techniques were used to study fish community structure, distribution, and diel movements of fish on Zhubi Reef to enhance understanding of the ecosystem. We collected 126 individuals from 29 species, 20 genera, 17 families, three orders, and two classes using traditional gear. Perciforms were the dominant group in terms of species richness and biomass. The acoustic data indicated that very small (target strength [TS], dB) <-60 dB) and small (-60 dB≤TS<-45 dB) fish contributed the most to abundance and species richness on the coral reef, and that the proportion of medium-sized (-45 dB≤TS<-35 dB) and large-sized (-35 dB≤TS) fish increased gradually as depth increased. The single-target detection method revealed two distinct size classes during the day in the 12-16 and 16-20-m layers. One group consisted of very small-sized fish (TS<-60 dB) and the other consisted of medium and large-sized fish (TS>-55 dB). The number of single-target detections was significantly higher during the night than during the day ( P<0.05). The singletarget TS frequency distribution during the day was significantly different than during the night at depths of 4-8, 8-12, 12-16, and 16-20 m. Significant differences were observed among the 4-8, 8-12, 12-16, and 16-20-m-depth layers during day and night. Diel vertical movement was evidenced as fish began to spread and move upward just before sunset and began to assemble and descend shortly (15 min) after sunrise.

  3. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Northwest): Amphipods. [Gammaridea; Hyperidea; Caprellidea

    SciTech Connect

    Grosse, D.J.; Pauley, G.B.; Moran, D.

    1986-08-01

    Amphipods are ubiquitous in distribution. Hyperiidea are the third most abundant coastal marine crustacean zooplankton, following copepods and euphausids. Benthic Gammaridea are an invaluable food source for many economically important fish and invertebrate species. Lifestyles of the major amphipod groups are varied. On the basis of the Index of Relative Importance (IRI), they comprise more than half of the total IRI spectrum for 38 of 55 fish species in the Strait of Juan de Fuca. They are reported to be indicators of heavily polluted areas.

  4. Species abundance in a forest community in South China: A case of poisson lognormal distribution

    USGS Publications Warehouse

    Yin, Z.-Y.; Ren, H.; Zhang, Q.-M.; Peng, S.-L.; Guo, Q.-F.; Zhou, G.-Y.

    2005-01-01

    Case studies on Poisson lognormal distribution of species abundance have been rare, especially in forest communities. We propose a numerical method to fit the Poisson lognormal to the species abundance data at an evergreen mixed forest in the Dinghushan Biosphere Reserve, South China. Plants in the tree, shrub and herb layers in 25 quadrats of 20 m??20 m, 5 m??5 m, and 1 m??1 m were surveyed. Results indicated that: (i) for each layer, the observed species abundance with a similarly small median, mode, and a variance larger than the mean was reverse J-shaped and followed well the zero-truncated Poisson lognormal; (ii) the coefficient of variation, skewness and kurtosis of abundance, and two Poisson lognormal parameters (?? and ??) for shrub layer were closer to those for the herb layer than those for the tree layer; and (iii) from the tree to the shrub to the herb layer, the ?? and the coefficient of variation decreased, whereas diversity increased. We suggest that: (i) the species abundance distributions in the three layers reflects the overall community characteristics; (ii) the Poisson lognormal can describe the species abundance distribution in diverse communities with a few abundant species but many rare species; and (iii) 1/?? should be an alternative measure of diversity.

  5. Spatial distribution of fifty ornamental fish species on coral reefs in the Red Sea and Gulf of Aden.

    PubMed

    Khalaf, Maroof A; Abdallah, Mohamed

    2014-01-01

    The spatial distribution of 50 ornamental fish species from shallow water habitats on coral reefs were investigated using visual census techniques, between latitudes 11-29°N in the Red Sea, in Jordan, Egypt, Saudi Arabia, and Yemen, and in the adjacent Gulf of Aden in Djibouti. One hundred eighteen transects (each 100×5 m) were examined in 29 sites (3-8 sites per country). A total of 522,523 fish individuals were counted during this survey, with mean abundance of 4428.2 ± 87.26 individual per 500 m² transect. In terms of relative abundance (RA), the most abundant species were Blue green damselfish, Chromis viridis (RA=54.4%),followed bySea goldie, Pseudanthias squamipinnis (RA= 34.7), Whitetail dascyllus, Dascyllus aruanus (RA= 2.6%), Marginate dascyllus, Dascyllus marginatus (RA= 2.0),Red Sea eightline flasher Paracheilinus octotaenia (RA=1.0),andKlunzinger's wrasse, Thalassoma rueppellii (0.7%). The highest number of species (S) per 500 m² transect was found on reefs at the latitude 20° in Saudi Arabia (S=21.8), and the lowest number of species was found at the latitude 15° in Djibouti (S=11.11). The highest mean abundance (8565.8) was found on reefs at latitude 20° in Saudi Arabia and the lowest mean abundance (230) was found on reefs at latitude 22°, also in Saudi Arabia. Whereas, the highest Shannon-Wiener Diversity Index was found in reefs at the latitude 22° (H`=2.4) and the lowest was found in reefs at the latitude 20° (H`=0.6). This study revealed marked differences in the structure of ornamental fish assemblages with latitudinal distribution. The data support the presence of two major biogeographic groups of fishes in the Red Sea and Gulf of Aden: the southern Red Sea and Gulf of Aden group and the group in the northern and central Red Sea. Strong correlations were found between live coral cover and the number of fish species, abundance and Shannon-Wiener Diversity indices, and the strength of these correlations varied among the reefs. A

  6. Spatial distribution of fifty ornamental fish species on coral reefs in the Red Sea and Gulf of Aden

    PubMed Central

    Khalaf, Maroof A.; Abdallah, Mohamed

    2014-01-01

    Abstract The spatial distribution of 50 ornamental fish species from shallow water habitats on coral reefs were investigated using visual census techniques, between latitudes 11−29°N in the Red Sea, in Jordan, Egypt, Saudi Arabia, and Yemen, and in the adjacent Gulf of Aden in Djibouti. One hundred eighteen transects (each 100×5 m) were examined in 29 sites (3−8 sites per country). A total of 522,523 fish individuals were counted during this survey, with mean abundance of 4428.2 ± 87.26 individual per 500 m² transect. In terms of relative abundance (RA), the most abundant species were Blue green damselfish, Chromis viridis (RA=54.4%),followed bySea goldie, Pseudanthias squamipinnis (RA= 34.7), Whitetail dascyllus, Dascyllus aruanus (RA= 2.6%), Marginate dascyllus, Dascyllus marginatus (RA= 2.0),Red Sea eightline flasher Paracheilinus octotaenia (RA=1.0),andKlunzinger’s wrasse, Thalassoma rueppellii (0.7%). The highest number of species (S) per 500 m² transect was found on reefs at the latitude 20° in Saudi Arabia (S=21.8), and the lowest number of species was found at the latitude 15° in Djibouti (S=11.11). The highest mean abundance (8565.8) was found on reefs at latitude 20° in Saudi Arabia and the lowest mean abundance (230) was found on reefs at latitude 22°, also in Saudi Arabia. Whereas, the highest Shannon-Wiener Diversity Index was found in reefs at the latitude 22° (H`=2.4) and the lowest was found in reefs at the latitude 20° (H`=0.6). This study revealed marked differences in the structure of ornamental fish assemblages with latitudinal distribution. The data support the presence of two major biogeographic groups of fishes in the Red Sea and Gulf of Aden: the southern Red Sea and Gulf of Aden group and the group in the northern and central Red Sea. Strong correlations were found between live coral cover and the number of fish species, abundance and Shannon-Wiener Diversity indices, and the strength of these correlations varied among the

  7. New Insights on Jupiter's Deep Water Abundance from Disequilibrium Species

    NASA Astrophysics Data System (ADS)

    Wang, Dong; Gierasch, Peter; Lunine, Jonathan; Mousis, Olivier

    2014-11-01

    The bulk water abundance on Jupiter potentially constrains the planet's formation conditions. We aim to improve the chemical constraints on Jupiter's deep water abundance in this paper. The eddy diffusion coefficient is used to model vertical mixing in planetary atmosphere, and based on laboratory studies dedicated to turbulent rotating convection, we propose a new formulation of eddy diffusion coefficient. The new formulation predicts a smooth transition from slow rotation regime (near the equator) to the rapid rotation regime (near the pole). We estimate an uncertainty for newly derived coefficient of less than 25%, which is much better than the one order of magnitude uncertainty used in the literature. We then reevaluate the water constraintprovided by CO, using the newer eddy diffusion coefficient. We considered two updated CO kinetic models, one model constrains the water enrichment (relative to solar) between 0.1 and 0.75, while the other one constrains the water enrichment between 7 and 23. This difference calls for a better assessment of CO kinetic models.

  8. New insights on Jupiter's deep water abundance from disequilibrium species

    NASA Astrophysics Data System (ADS)

    Wang, Dong; Gierasch, Peter J.; Lunine, Jonathan I.; Mousis, Olivier

    2015-04-01

    The bulk water abundance on Jupiter potentially constrains the planet's formation conditions. We improve the chemical constraints on Jupiter's deep water abundance in this paper. The eddy diffusion coefficient is used to model vertical mixing in planetary atmosphere, and based on laboratory studies dedicated to turbulent rotating convection, we propose a new formulation of the eddy diffusion coefficient for the troposphere of giant planets. The new formulation predicts a smooth transition from the slow rotation regime (near the equator) to the rapid rotation regime (near the pole). We estimate an uncertainty for the newly derived coefficient of less than 25%, which is much better than the one order of magnitude uncertainty used in the literature. We then reevaluate the water constraint provided by CO, using the newer eddy diffusion coefficient. We considered two updated CO kinetic models, one model constrains the water enrichment (relative to solar) between 0.1 and 0.75, while the other constrains the water enrichment between 3 and 11.

  9. Four parasitic Crustacean species from marine fishes of Turkey.

    PubMed

    Oguz, Mehmet Cemal; Oktener, Ahmet

    2007-01-01

    The aim of this work was to present a preliminary knowledge of the parasitic copepods of marine fish of Turkey. In this study, four parasitic crustaceans were reported from five different fish species found in Turkish seas: Lepeophtheirus europaensis (Zeddam, Berrebi, Renaud, Raibaut & Gabrion, 1988) was found on the gills of the European flounder, Platichtys flesus (Linnaeus, 1758 (Pleuronectidae); Nerocila bivittata (Risso, 1816) on caudal peduncles of east Atlantic peacock wrasse, Symphodus tinca (Linnaeus, 1758) (Labridae); Ceratothoa oestroides (Risso, 1826), on the mouth base of European pilchard, Sardina pilchardus (Walbaum, 1792) (Clupeidae); Anilocra physodes (Linnaeus, 1758), on the body surface of gilthead seabreams, Sparus aurata Linnaeus, 1758 (Sparidae) and on horse mackerel, Trachurus trachurus (Linnaeus, 1758) (Carangidae). Also, a list of the parasitic copepods previously reported from marine fishes of Turkey since 1931 is given, with a new report of the host species, the localities where they were collected and the corresponding authors. At the present time, 23 parasitic copepods have been recorded from 25 host fish of Turkish coasts. Lepeophtheirus europaensis Zeddam, Berrebi, Renaud, Raibaut & Gabrion, 1988 was reported for the first time in Turkish coastal waters. PMID:17471420

  10. Characterization of antioxidant system parameters in four freshwater fish species.

    PubMed

    Atli, Gülüzar; Canli, Esin G; Eroglu, Ali; Canli, Mustafa

    2016-04-01

    The potential use of antioxidant system parameters has gained considerable interest due to their pivotal role of detoxification mechanisms in environmental studies and culture fish point of view. Fish with different ecological needs may have different antioxidant capacity and response to environmental contaminants. Thus, the optimal working conditions and specific enzyme activities (Vmax and Km) of antioxidant system parameters (Superoxide dismutase, SOD; Catalase, CAT; Glutathione peroxidase, GPX; Glutathione reductase, GR and Glutathione S-transferase, GST) and glutathione (GSH) were determined in four commonly cultured freshwater fish species (tilapia; Oreochromis niloticus, carp; Cyprinus carpio, trout; Onchorhynchus mykiss and catfish; Clarias garipienus). Data showed that optimal concentrations of different buffers, pH and specific chemicals for each enzyme and GSH were similar in most cases for all fish species, except a few differences. The highest Vmax and Km values were found in carp for GPX and GST, though these values were the highest in tilapia, catfish and trout for CAT, SOD and GR, respectively. As a conclusion, optimization assays of these parameters in different bioindicator organisms based on their physiological and ecological differences may be useful for the aquatic ecosystem biomonitoring studies and also present fundamental data for utilization in aquaculture. PMID:26707186

  11. Global patterns and predictors of fish species richness in estuaries.

    PubMed

    Vasconcelos, Rita P; Henriques, Sofia; França, Susana; Pasquaud, Stéphanie; Cardoso, Inês; Laborde, Marina; Cabral, Henrique N

    2015-09-01

    1. Knowledge of global patterns of biodiversity and regulating variables is indispensable to develop predictive models. 2. The present study used predictive modelling approaches to investigate hypotheses that explain the variation in fish species richness between estuaries over a worldwide spatial extent. Ultimately, such models will allow assessment of future changes in ecosystem structure and function as a result of environmental changes. 3. A comprehensive worldwide data base was compiled of the fish assemblage composition and environmental characteristics of estuaries. Generalized Linear Models were used to quantify how variation in species richness among estuaries is related to historical events, energy dynamics and ecosystem characteristics, while controlling for sampling effects. 4. At the global extent, species richness differed among marine biogeographic realms and continents and increased with mean sea surface temperature, terrestrial net primary productivity and the stability of connectivity with a marine ecosystem (open vs. temporarily open estuaries). At a smaller extent (within a marine biogeographic realm or continent), other characteristics were also important in predicting variation in species richness, with species richness increasing with estuary area and continental shelf width. 5. The results suggest that species richness in an estuary is defined by predictors that are spatially hierarchical. Over the largest spatial extents, species richness is influenced by the broader distributions and habitat use patterns of marine and freshwater species that can colonize estuaries, which are in turn governed by history contingency, energy dynamics and productivity variables. Species richness is also influenced by more regional and local parameters that can further affect the process of community colonization in an estuary including the connectivity of the estuary with the adjacent marine habitat, and, over smaller spatial extents, the size of these

  12. Use of classification trees to apportion single echo detections to species: Application to the pelagic fish community of Lake Superior

    USGS Publications Warehouse

    Yule, Daniel L.; Adams, Jean V.; Hrabik, Thomas R.; Vinson, Mark R.; Woiak, Zebadiah; Ahrenstroff, Tyler D.

    2013-01-01

    Acoustic methods are used to estimate the density of pelagic fish in large lakes with results of midwater trawling used to assign species composition. Apportionment in lakes having mixed species can be challenging because only a small fraction of the water sampled acoustically is sampled with trawl gear. Here we describe a new method where single echo detections (SEDs) are assigned to species based on classification tree models developed from catch data that separate species based on fish size and the spatial habitats they occupy. During the summer of 2011, we conducted a spatially-balanced lake-wide acoustic and midwater trawl survey of Lake Superior. A total of 51 sites in four bathymetric depth strata (0–30 m, 30–100 m, 100–200 m, and >200 m) were sampled. We developed classification tree models for each stratum and found fish length was the most important variable for separating species. To apply these trees to the acoustic data, we needed to identify a target strength to length (TS-to-L) relationship appropriate for all abundant Lake Superior pelagic species. We tested performance of 7 general (i.e., multi-species) relationships derived from three published studies. The best-performing relationship was identified by comparing predicted and observed catch compositions using a second independent Lake Superior data set. Once identified, the relationship was used to predict lengths of SEDs from the lake-wide survey, and the classification tree models were used to assign each SED to a species. Exotic rainbow smelt (Osmerus mordax) were the most common species at bathymetric depths 100 m (384 million; 6.0 kt). Cisco (Coregonus artedi) were widely distributed over all strata with their population estimated at 182 million (44 kt). The apportionment method we describe should be transferable to other large lakes provided fish are not tightly aggregated, and an appropriate TS-to-L relationship for abundant pelagic fish species can be determined.

  13. DISTRIBUTIONS OF LAKE FISHES OF THE NORTHEAST USA--III. SALMONIDAE AND ASSOCIATED COLDWATER SPECIES

    EPA Science Inventory

    We present distributional maps and discuss native status for fish species characteristic of coldwater lakes, sampled from 203 randomly selected lakes in the northeastern USA (New England, New York, New Jersey). Eleven coldwater fish species from four families (Salmonidae, Osmeri...

  14. Organochlorine pesticides in bird species and their prey (fish) from the Ethiopian Rift Valley region, Ethiopia.

    PubMed

    Yohannes, Yared Beyene; Ikenaka, Yoshinori; Nakayama, Shouta M M; Ishizuka, Mayumi

    2014-09-01

    Organochlorine pesticides (OCPs) and stable isotopes were measured in muscle from 4 bird and 5 fish species from the Ethiopian Rift Valley region where DDT is used for malaria control and vast agricultural activities are carried out. We investigated the bioaccumulation of OCPs such as DDTs, HCHs, chlordanes, and heptachlors between the species, and examined the potential risk posed by these compounds for bird species. Significant differences in contaminant profiles and levels were observed within the species. Levels of total OCPs ranged from 3.7 to 148.7 μg/g lipid in bird and 0.04 to 10.9 μg/g lipid in fish species. DDTs were the predominant contaminant, and a positive relationship between δ(15)N and ΣDDT concentrations was found. The main DDT metabolite, p,p'-DDE was the most abundant and significantly greater concentrations in bird species (up to 138.5 μg/g lipid), which could have deleterious effects on survival and/or reproduction of birds. PMID:24907858

  15. Lactobacillus and Pediococcus species richness and relative abundance in the vagina of rhesus monkeys (Macaca mulatta)

    PubMed Central

    Gravett, Michael G.; Jin, Ling; Pavlova, Sylvia I.; Tao, Lin

    2012-01-01

    Background The rhesus monkey is an important animal model to study human vaginal health to which lactic acid bacteria play a significant role. However, the vaginal lactic acid bacterial species richness and relative abundance in rhesus monkeys is largely unknown. Methods Vaginal swab samples were aseptically obtained from 200 reproductive aged female rhesus monkeys. Following Rogosa agar plating, single bacterial colonies representing different morphotypes were isolated and analyzed for whole-cell protein profile, species-specifc PCR, and 16S rRNA gene sequence. Results A total of 510 Lactobacillus strains of 17 species and one Pediococcus acidilactici were identified. The most abundant species was L. reuteri, which colonized the vaginas of 86% monkeys. L. johnsonii was the second most abundant species, which colonized 36% of monkeys. The majority of monkeys were colonized by multiple Lactobacillus species. Conclusions The vaginas of rhesus monkeys are frequently colonized by multiple Lactobacillus species, dominated by L. reuteri. PMID:22429090

  16. Mineral Element Contents in Commercially Valuable Fish Species in Spain

    PubMed Central

    Peña-Rivas, Luis; Ortega, Eduardo; López-Martínez, Concepción; Olea-Serrano, Fátima; Lorenzo, Maria Luisa

    2014-01-01

    The aim of this study was to measure selected metal concentrations in Trachurus trachurus, Trachurus picturatus, and Trachurus mediterraneus, which are widely consumed in Spain. Principal component analysis suggested that the variable Cr was the main responsible variable for the identification of T. trachurus, the variables As and Sn for T. mediterraneus, and the rest of variables for T. picturatus. This well-defined discrimination between fish species provided by mineral element allows us to distinguish them on the basis of their metal content. Based on the samples collected, and recognizing the inferential limitation of the sample size of this study, the metal concentrations found are below the proposed limit values for human consumption. However, it should be taken into consideration that there are other dietary sources of these metals. In conclusion, metal contents in the fish species analyzed are acceptable for human consumption from a nutritional and toxicity point of view. PMID:24895678

  17. Urbanization Level and Woodland Size Are Major Drivers of Woodpecker Species Richness and Abundance

    PubMed Central

    Myczko, Łukasz; Rosin, Zuzanna M.; Skórka, Piotr; Tryjanowski, Piotr

    2014-01-01

    Urbanization is a process globally responsible for loss of biodiversity and for biological homogenization. Urbanization may have a direct negative impact on species behaviour and indirect effects on species populations through alterations of their habitats, for example patch size and habitat quality. Woodpeckers are species potentially susceptible to urbanization. These birds are mostly forest specialists and the development of urban areas in former forests may be an important factor influencing their richness and abundance, but documented examples are rare. In this study we investigated how woodpeckers responded to changes in forest habitats as a consequence of urbanization, namely size and isolation of habitat patches, and other within-patch characteristics. We selected 42 woodland patches in a gradient from a semi-natural rural landscape to the city centre of Poznań (Western Poland) in spring 2010. Both species richness and abundance of woodpeckers correlated positively to woodland patch area and negatively to increasing urbanization. Abundance of woodpeckers was also positively correlated with shrub cover and percentage of deciduous tree species. Furthermore, species richness and abundance of woodpeckers were highest at moderate values of canopy openness. Ordination analyses confirmed that urbanization level and woodland patch area were variables contributing most to species abundance in the woodpecker community. Similar results were obtained in presence-absence models for particular species. Thus, to sustain woodpecker species within cities it is important to keep woodland patches large, multi-layered and rich in deciduous tree species. PMID:24740155

  18. Nursery use patterns of commercially important marine fish species in estuarine systems along the Portuguese coast

    NASA Astrophysics Data System (ADS)

    Vasconcelos, R. P.; Reis-Santos, P.; Maia, A.; Fonseca, V.; França, S.; Wouters, N.; Costa, M. J.; Cabral, H. N.

    2010-03-01

    Analysing the estuarine use patterns of juveniles of marine migrant fish species is vital for identifying important sites for juveniles as well as the basic environmental features that characterize these sites for different species. This is a key aspect towards understanding nursery function. Various estuarine systems along the Portuguese coast (Minho, Douro, Ria de Aveiro, Mondego, Tejo, Sado, Mira, Ria Formosa and Guadiana) were sampled during Spring and Summer 2005 and 2006. Juveniles of commercially important marine fish species Solea solea, Solea senegalensis, Platichthys flesus, Diplodus vulgaris and Dicentrarchus labrax, predominantly 0-group individuals, were amongst the most abundant species and had distinct patterns of estuarine use as well as conspicuous associations with several environmental features. Juvenile occurrence and density varied amongst estuaries and sites within them, and differed with species. Sites with consistently high juvenile densities were identified as important juvenile sites (i.e. putative nursery grounds). Through generalized linear models (GLM), intra-estuarine variation in occurrence and density of each of the individual species was largely explained by environmental variables (temperature; salinity; depth; percentage of mud in the sediment; presence of seagrass; importance of intertidal areas; relative distance to estuary mouth; macrozoobenthos densities; and latitude). Decisive environmental factors defining important sites for juveniles varied depending on the system as a result of different environmental gradients, though there were common dominant features for each species regardless of the estuary considered. Analysed environmental variables in the GLM also accounted for inter-estuarine variation in species' occurrence and density. In several estuaries, the identified important juvenile sites were used by many of these species simultaneously and may be of increased value to both management and conservation. Overall, the

  19. [Species and size composition of fishes in Barra de Navidad lagoon, Mexican central Pacific].

    PubMed

    González-Sansón, Gaspar; Aguilar-Betancourt, Consuelo; Kosonoy-Aceves, Daniel; Lucano-Ramírez, Gabriela; Ruiz-Ramírez, Salvador; Flores-Ortega, Juan Ramón; Hinojosa-Larios, Angel; de Asís Silva-Bátiz, Francisco

    2014-03-01

    Coastal lagoons are considered important nursery areas for many coastal fishes. Barra de Navidad coastal lagoon (3.76km2) is important for local economy as it supports tourism development and artisanal fisheries. However, the role of this lagoon in the dynamics of coastal fish populations is scarcely known. Thus, the objectives of this research were: to characterize the water of the lagoon and related weather conditions, to develop a systematic list of the ichthyofauna, and to estimate the proportion of juveniles in the total number of individuals captured of most abundant species. Water and fish samples were collected between March 2011 and February 2012. Physical and chemical variables were measured in rainy and dry seasons. Several fishing gears were used including a cast net, beach purse seine and gillnets of four different mesh sizes. Our results showed that the lagoon is most of the time euhaline (salinity 30-40ups), although it can be mixopolyhaline (salinity 18-30ups) during short periods. Chlorophyll and nutrients concentrations suggested eutrophication in the lagoon. Mean water temperature changed seasonally from 24.9 degrees C (April, high tide) to 31.4 degrees C (October, low tide). Considering ichthyofauna species, a total of 36 448 individuals of 92 species were collected, 31 of them adding up to 95% of the total of individuals caught. Dominant species were Anchoa spp. (44.6%), Diapterus peruvianus (10.5%), Eucinostomus currani (8.1%), Cetengraulis mysticetus (7.8%), Mugil curema (5.2%) and Opisthonema libertate (4.5%). The lagoon is an important juvenile habitat for 22 of the 31 most abundant species. These included several species of commercial importance such as snappers (Lutjanus argentiventris, L. colorado and L. novemfasciatus), snook (Centropomus nigrescens) and white mullet (Mugil curema). Other four species seem to use the lagoon mainly as adults. This paper is the first contribution on the composition of estuarine ichthyofauna in Jalisco

  20. Semiparametric bivariate zero-inflated Poisson models with application to studies of abundance for multiple species

    USGS Publications Warehouse

    Arab, Ali; Holan, Scott H.; Wikle, Christopher K.; Wildhaber, Mark L.

    2012-01-01

    Ecological studies involving counts of abundance, presence–absence or occupancy rates often produce data having a substantial proportion of zeros. Furthermore, these types of processes are typically multivariate and only adequately described by complex nonlinear relationships involving externally measured covariates. Ignoring these aspects of the data and implementing standard approaches can lead to models that fail to provide adequate scientific understanding of the underlying ecological processes, possibly resulting in a loss of inferential power. One method of dealing with data having excess zeros is to consider the class of univariate zero-inflated generalized linear models. However, this class of models fails to address the multivariate and nonlinear aspects associated with the data usually encountered in practice. Therefore, we propose a semiparametric bivariate zero-inflated Poisson model that takes into account both of these data attributes. The general modeling framework is hierarchical Bayes and is suitable for a broad range of applications. We demonstrate the effectiveness of our model through a motivating example on modeling catch per unit area for multiple species using data from the Missouri River Benthic Fishes Study, implemented by the United States Geological Survey.

  1. Abundance of minor ion species at Mars: ASPERA-3 observations

    NASA Astrophysics Data System (ADS)

    Zhang, Yiteng; Nilsson, Hans; Barabash, Stas; Li, Lei

    2012-07-01

    The main species at Mars are O+, O2+, CO2+, while there are also some minor species. This article successfully separates minor species of O++, He+ and H2+ with about 12eV by integrating from two and a half years ASPERA-3 data on Mars Express and by integrating and taking some corrections and data processing. At the same time some space statistic Statistics of these Mars ions and estimating are taken place. The result indicates O++ ions density reduce quickly in the region without sunlight, and have moreis higher at subsolar than in the high alatitude place,. and reduces quickly in the region without sunlight. He+ and H2+ have similar distribution in space mainly above in the high altitude ionosphere, and relatively reduce sparse in the midnight space. O++ and He+ have a comparable volume density about 0.1% of O+, and H2+ is muchone order of magnitude lowerless for one order. Our results imply that O++ ions in the martian space are mainly the product of phtoionization in the ionosphere, while H2+ and He+ might also be originated in the planet.

  2. Species Composition and Abundance of Stink Bugs (Hemiptera: Heteroptera: Pentatomidae) in Minnesota Field Corn.

    PubMed

    Koch, Robert L; Pahs, Tiffany

    2015-04-01

    In response to concerns of increasing significance of stink bugs (Hemiptera: Heteroptera: Pentatomidae) in northern states, a survey was conducted over 2 yr in Minnesota to characterize the Pentatomidae associated with field corn, Zea mays L. Halyomorpha halys (Stål), an exotic species, was not detected in this survey, despite continued detection of this species as an invader of human-made structures in Minnesota. Five species of Pentatomidae (four herbivorous; one predatory) were collected from corn. Across years, Euschistus variolarius (Palisot de Beauvois) and Euschistus servus euschistoides (Vollenhoven) had the greatest relative abundances and frequencies of detection. In 2012, the abundance of herbivorous species exceeded 25 nymphs and adults per 100 plants (i.e., an economic threshold) in 0.48% of fields. However, the abundance of herbivorous species did not reach economic levels in any fields sampled in 2013. The frequency of detection of herbivorous species and ratio of nymphs to adults was highest during reproductive growth stages of corn. The predator species, Podisus maculiventris (Say), was detected in 0 to 0.32% of fields. These results provide baseline information on the species composition and abundance of Pentatomidae in Minnesota field corn, which will be necessary for documentation of changes to this fauna as a result of the invasion of H. halys and to determine if some native species continue to increase in abundance in field crops. PMID:26313176

  3. Unveiling the species-rank abundance distribution by generalizing the Good-Turing sample coverage theory.

    PubMed

    Chao, Anne; Hsieh, T C; Chazdon, Robin L; Colwell, Robert K; Gotelli, Nicholas J

    2015-05-01

    Based on a sample of individuals, we focus on inferring the vector of species relative abundance of an entire assemblage and propose a novel estimator of the complete species-rank abundance distribution (RAD). Nearly all previous estimators of the RAD use the conventional "plug-in" estimator Pi (sample relative abundance) of the true relative abundance pi of species i. Because most biodiversity samples are incomplete, the plug-in estimators are applied only to the subset of species that are detected in the sample. Using the concept of sample coverage and its generalization, we propose a new statistical framework to estimate the complete RAD by separately adjusting the sample relative abundances for the set of species detected in the sample and estimating the relative abundances for the set of species undetected in the sample but inferred to be present in the assemblage. We first show that P, is a positively biased estimator of pi for species detected in the sample, and that the degree of bias increases with increasing relative rarity of each species. We next derive a method to adjust the sample relative abundance to reduce the positive bias inherent in j. The adjustment method provides a nonparametric resolution to the longstanding challenge of characterizing the relationship between the true relative abundance in the entire assemblage and the observed relative abundance in a sample. Finally, we propose a method to estimate the true relative abundances of the undetected species based on a lower bound of the number of undetected species. We then combine the adjusted RAD for the detected species and the estimated RAD for the undetected species to obtain the complete RAD estimator. Simulation results show that the proposed RAD curve can unveil the true RAD and is more accurate than the empirical RAD. We also extend our method to incidence data. Our formulas and estimators are illustrated using empirical data sets from surveys of forest spiders (for abundance data) and

  4. Species-abundance--seed-size patterns within a plant community affected by grazing disturbance.

    PubMed

    Wu, Gao-lin; Shang, Zhan-huan; Zhu, Yuan-jun; Ding, Lu-ming; Wang, Dong

    2015-04-01

    Seed size has been advanced as a key factor that influences the dynamics of plant communities, but there are few empirical or theoretical predictions of how community dynamics progress based on seed size patterns. Information on the abundance of adults, seedlings, soil seed banks, seed rains, and the seed mass of 96 species was collected in alpine meadows of the Qinghai-Tibetan Plateau (China), which had different levels of grazing disturbance. The relationships between seed-mass-abundance patterns for adults, seedlings, the soil seed bank, and seed rain in the plant community were evaluated using regression models. Results showed that grazing levels affected the relationship between seed size and abundance properties of adult species, seedlings, and the soil seed bank, suggesting that there is a shift in seed-size--species-abundance relationships as a response to the grazing gradient. Grazing had no effect on the pattern of seed-size-seed-rain-abundance at four grazing levels. Grazing also had little effect on the pattern of seed-size--species-abundance and pattern of seed-size--soil-seed-bank-abundance in meadows with no grazing, light grazing, and moderate grazing), but there was a significant negative effect in meadows with heavy grazing. Grazing had little effect on the pattern of seed-size--seedling-abundance with no grazing, but had significant negative effects with light, moderate, and heavy grazing, and the |r| values increased with grazing levels. This indicated that increasing grazing pressure enhanced the advantage of smaller-seeded species in terms of the abundances of adult species, seedlings, and soil seed banks, whereas only the light grazing level promoted the seed rain abundance of larger-seeded species in the plant communities. This study suggests that grazing disturbances are favorable for increasing the species abundance for smaller-seeded species but not for the larger-seeded species in an alpine meadow community. Hence, there is a clear

  5. A Common Scaling Rule for Abundance, Energetics, and Production of Parasitic and Free-Living Species

    PubMed Central

    Hechinger, Ryan F.; Lafferty, Kevin D.; Dobson, Andy P.; Brown, James H.; Kuris, Armand M.

    2011-01-01

    The metabolic theory of ecology uses the scaling of metabolism with body size and temperature to explain the causes and consequences of species abundance. However, the theory and its empirical tests have never simultaneously examined parasites alongside free-living species. This is unfortunate because parasites represent at least half of species diversity. We show that metabolic scaling theory could not account for the abundance of parasitic or free-living species in three estuarine food webs until accounting for trophic dynamics. Analyses then revealed that the abundance of all species uniformly scaled with body mass to the −¾ power. This result indicates “production equivalence,” where biomass production within trophic levels is invariant of body size across all species and functional groups: invertebrate or vertebrate, ectothermic or endothermic, and free-living or parasitic. PMID:21778398

  6. Accounting for dispersal and biotic interactions to disentangle the drivers of species distributions and their abundances

    PubMed Central

    Boulangeat, Isabelle; Gravel, Dominique; Thuiller, Wilfried

    2014-01-01

    Although abiotic factors, together with dispersal and biotic interactions, are often suggested to explain the distribution of species and their abundances, species distribution models usually focus on abiotic factors only. We propose an integrative framework linking ecological theory, empirical data and statistical models to understand the distribution of species and their abundances together with the underlying community assembly dynamics. We illustrate our approach with 21 plant species in the French Alps. We show that a spatially nested modelling framework significantly improves the model’s performance and that the spatial variations of species presence–absence and abundances are predominantly explained by different factors. We also show that incorporating abiotic, dispersal and biotic factors into the same model bring new insights to our understanding of community assembly. This approach, at the crossroads between community ecology and biogeography, is a promising avenue for a better understanding of species co-existence and biodiversity distribution. PMID:22462813

  7. A common scaling rule for abundance, energetics, and production of parasitic and free-living species

    USGS Publications Warehouse

    Hechinger, Ryan F.; Lafferty, Kevin D.; Dobson, Andy P.; Brown, James H.; Kuris, Armand M.

    2011-01-01

    The metabolic theory of ecology uses the scaling of metabolism with body size and temperature to explain the causes and consequences of species abundance. However, the theory and its empirical tests have never simultaneously examined parasites alongside free-living species. This is unfortunate because parasites represent at least half of species diversity. We show that metabolic scaling theory could not account for the abundance of parasitic or free-living species in three estuarine food webs until accounting for trophic dynamics. Analyses then revealed that the abundance of all species uniformly scaled with body mass to the - 3/4 power. This result indicates "production equivalence," where biomass production within trophic levels is invariant of body size across all species and functional groups: invertebrate or vertebrate, ectothermic or endothermic, and free-living or parasitic.

  8. Macroalgal mats and species abundance: a field experiment

    NASA Astrophysics Data System (ADS)

    Hull, S. C.

    1987-11-01

    A field experiment was carried out whereby the density of macroalgae ( Enteromorpha spp.) was manipulated and the resultant changes in sediment infaunal density were monitored. Four densities of Enteromorpha spp. were used: 0,0·3, 1, and 3 kg FW m -2, corresponding to control, low-, medium-, and high-density plots. The experiment ran from May to October 1985 and was sampled on three occasions. By July, the density of Corophium volutator was reduced at all weed levels when compared to control plots, whereas densities of Hydrobia ulvae, Macoma balthica, Nereis diversicolor, and Capitella capitata, all increased. Samples taken in October when the weed mats were buried in the sediment showed fewer differences than in July. Macoma, Nereis, and Capitella were still significantly more abundant at medium and high weed densities. Corophium showed no significant treatment effect. There was, however, a highly significant difference in population size structure for Corophium. Measurements of sediment redox potential and silt content under medium- and high-density plots revealed rapid anoxia with a significant increase in siltation.

  9. The effect of soil-borne pathogens depends on the abundance of host tree species

    PubMed Central

    Liu, Yu; Fang, Suqin; Chesson, Peter; He, Fangliang

    2015-01-01

    The overarching issue for understanding biodiversity maintenance is how fitness advantages accrue to a species as it becomes rare, as this is the defining feature of stable coexistence mechanisms. Without these fitness advantages, average fitness differences between species will lead to exclusion. However, empirical evidence is lacking, especially for forests, due to the difficulty of manipulating density on a large-enough scale. Here we took advantage of naturally occurring contrasts in abundance between sites of a subtropical tree species, Ormosia glaberrima, to demonstrate how low-density fitness advantages accrue by the Janzen–Connell mechanism. The results showed that soil pathogens suppressed seedling recruitment of O. glaberrima when it is abundant but had little effect on the seedlings when it is at low density due to the lack of pathogens. The difference in seedling survival between abundant and low-density sites demonstrates strong dependence of pathogenic effect on the abundance of host species. PMID:26632594

  10. The effect of soil-borne pathogens depends on the abundance of host tree species.

    PubMed

    Liu, Yu; Fang, Suqin; Chesson, Peter; He, Fangliang

    2015-01-01

    The overarching issue for understanding biodiversity maintenance is how fitness advantages accrue to a species as it becomes rare, as this is the defining feature of stable coexistence mechanisms. Without these fitness advantages, average fitness differences between species will lead to exclusion. However, empirical evidence is lacking, especially for forests, due to the difficulty of manipulating density on a large-enough scale. Here we took advantage of naturally occurring contrasts in abundance between sites of a subtropical tree species, Ormosia glaberrima, to demonstrate how low-density fitness advantages accrue by the Janzen-Connell mechanism. The results showed that soil pathogens suppressed seedling recruitment of O. glaberrima when it is abundant but had little effect on the seedlings when it is at low density due to the lack of pathogens. The difference in seedling survival between abundant and low-density sites demonstrates strong dependence of pathogenic effect on the abundance of host species. PMID:26632594

  11. Changes in the Relative Abundance of Two Saccharomyces Species from Oak Forests to Wine Fermentations.

    PubMed

    Dashko, Sofia; Liu, Ping; Volk, Helena; Butinar, Lorena; Piškur, Jure; Fay, Justin C

    2016-01-01

    Saccharomyces cerevisiae and its sibling species Saccharomyces paradoxus are known to inhabit temperate arboreal habitats across the globe. Despite their sympatric distribution in the wild, S. cerevisiae is predominantly associated with human fermentations. The apparent ecological differentiation of these species is particularly striking in Europe where S. paradoxus is abundant in forests and S. cerevisiae is abundant in vineyards. However, ecological differences may be confounded with geographic differences in species abundance. To compare the distribution and abundance of these two species we isolated Saccharomyces strains from over 1200 samples taken from vineyard and forest habitats in Slovenia. We isolated numerous strains of S. cerevisiae and S. paradoxus, as well as a small number of Saccharomyces kudriavzevii strains, from both vineyard and forest environments. We find S. cerevisiae less abundant than S. paradoxus on oak trees both within and outside the vineyard, but more abundant on grapevines and associated substrates. Analysis of the uncultured microbiome shows, that both S. cerevisiae and S. paradoxus are rare species in soil and bark samples, but can be much more common in grape must. In contrast to S. paradoxus, European strains of S. cerevisiae have acquired multiple traits thought to be important for life in the vineyard and dominance of wine fermentations. We conclude, that S. cerevisiae and S. paradoxus currently share both vineyard and non-vineyard habitats in Slovenia and we discuss factors relevant to their global distribution and relative abundance. PMID:26941733

  12. Changes in the Relative Abundance of Two Saccharomyces Species from Oak Forests to Wine Fermentations

    PubMed Central

    Dashko, Sofia; Liu, Ping; Volk, Helena; Butinar, Lorena; Piškur, Jure; Fay, Justin C.

    2016-01-01

    Saccharomyces cerevisiae and its sibling species Saccharomyces paradoxus are known to inhabit temperate arboreal habitats across the globe. Despite their sympatric distribution in the wild, S. cerevisiae is predominantly associated with human fermentations. The apparent ecological differentiation of these species is particularly striking in Europe where S. paradoxus is abundant in forests and S. cerevisiae is abundant in vineyards. However, ecological differences may be confounded with geographic differences in species abundance. To compare the distribution and abundance of these two species we isolated Saccharomyces strains from over 1200 samples taken from vineyard and forest habitats in Slovenia. We isolated numerous strains of S. cerevisiae and S. paradoxus, as well as a small number of Saccharomyces kudriavzevii strains, from both vineyard and forest environments. We find S. cerevisiae less abundant than S. paradoxus on oak trees both within and outside the vineyard, but more abundant on grapevines and associated substrates. Analysis of the uncultured microbiome shows, that both S. cerevisiae and S. paradoxus are rare species in soil and bark samples, but can be much more common in grape must. In contrast to S. paradoxus, European strains of S. cerevisiae have acquired multiple traits thought to be important for life in the vineyard and dominance of wine fermentations. We conclude, that S. cerevisiae and S. paradoxus currently share both vineyard and non-vineyard habitats in Slovenia and we discuss factors relevant to their global distribution and relative abundance. PMID:26941733

  13. Species richness and relative abundance of breeding birds in forests of the Mississippi Alluvial Valley

    USGS Publications Warehouse

    Nelms, C.O.; Twedt, D.J.

    1993-01-01

    In 1992, the Vicksburg Field Research Station of the National Wetlands Research Center initiated research on the ecology of migratory birds within forests of the Mississippi Alluvial Valley (MAV). The MAV was historically a nearly contiguous bottomland hardwood forest, however, only remnants remain. These remnants are fragmented and often influenced by drainage projects, silviculture, agriculture, and urban development. Our objectives are to assess species richness and relative abundance, and to relate these to the size, quality, and composition of forest stands. Species richness and relative abundance were estimated for 53 randomly selected forest sites using 1 to 8 point counts per site, depending on the size of the forest fragment. However, statistical comparisons among sites will be restricted to an equal number ofpoint counts within the sites being compared. Point counts, lasting five minutes, were conducted from 11 May to 29 June 1992, foltowing Ralph, Sauer, and Droege (Point Count Standards; memo dated 9 March 1992). Vegetation was measured at the first three points on each site using a modification of the methods employed by Martin and Roper (Condor 90: 5 1-57; 1988). During 252 counts, 7 1 species were encountered, but only 62 species were encountered within a 50-m radius of point center. The mean number of species encountered within 50 m of a point, was 7.3 (s.d. = 2.7) and the mean number of individuals was 11.2 (s.d. = 4.2). The mean number of species detected at any distance was 9.6 (s.d, = 2.8) and the mean number of individuals was 15.6 (s.d. = 7.9). The most frequently encountered warblers in the MAV were Prothonotary Warbler and Northern Parula. Rarely encountered warblers were American Redstart and Worm-eating Warbler. The genera, Quercus, Ulmus, Carya, and Celtis were each encountered at 80 or more of the 152 points at which vegetation was sampled. Species most frequentlyencountered were: sugarberry (Celtis laevagata), water hickory (Caqa

  14. Comparison of species composition and richness of fish assemblages in altered and unaltered littoral habitats

    USGS Publications Warehouse

    Poe, T.P.; Hatcher, C.O.; Brown, C.L.; Schloesser, D.W.

    1986-01-01

    Species composition and richness of fish assemblages in altered and unaltered littoral habitats in Lake St. Clair, Michigan, differed between areas. A percid-cyprinid-cyprinodontid assemblage dominated in the unaltered area, Muscamoot Bay, which has a natural shoreline (with almost no alteration due to dredging or bulkheading), high water quality, and high species richness of aquatic macrophytes. A centrarchid assemblage dominated in the altered area, Belvidere Bay, which has a bulkheaded shoreline, many dredged areas, reduced water quality due to inputs of nutrients from a nearby river, and relatively low species richness of aquatic macrophytes. Habitat factors, species richness and abundance of aquatic macrophytes, had the most influence on fish community structure in both areas. The percid-cyprinid-cyprinodontid assemblage was significantly correlated with six species of macrophytes whereas the centrarchid assemblage was significantly correlated with only four. These patterns suggest that preference for diverse habitats was higher, and tolerance to habitat alteration lower, in percid-cyprinid-cyprinodontid assemblages than in centrarchid assemblages.

  15. The life cycle of Prosorhynchoides carvajali (Trematoda: Bucephalidae) involving species of bivalve and fish hosts in the intertidal zone of central Chile.

    PubMed

    Muñoz, G; Valdivia, I; López, Z

    2015-09-01

    We describe the life cycle of the bucephalid Prosorhynchoides carvajali from the intertidal rocky zone of central Chile. To elucidate the life cycle of this digenean, two mytilid bivalves, Semimytilus algosus and Perumytilus purpuratus, and ten intertidal fish species belonging to the families Blenniidae, Tripterygiidae, Labrisomidae, Kyphosidae and Gobiesocidae were analysed for natural infections. In addition, experimental infections of fish were undertaken and molecular analyses were performed of several developmental stages of the digeneans in various host species. Experimental infections of fish were made from infected mytilids to determine which fish species were suitable for the metacercarial stage of Prosorhynchoides. We also determined the abundance and prevalence of metacercariae in natural infections in fish and found that they were lower than in the experimental infections. A molecular analysis showed that sporocysts from S. algosus were identical to metacercariae from five fish species and P. carvajali adults. Sporocysts isolated from P. purpuratus were similar to metacercaria found in one fish species only (G. laevifrons) but were different from P. carvajali, with 1.9-2.0% genetic divergence. Therefore, the complete life cycle of P. carvajali consists of the mytilid species S. algosus as the first intermediate host, at least five intertidal fish species as second intermediate hosts (Scartichthys viridis, Auchenionchus microcirrhis, Hypsoblennius sordidus, Helcogrammoides chilensis and Gobiesox marmoratus), two carnivorous fish as definitive hosts (Auchenionchus microcirrhis and A. variolosus) and one occasional definitive host (Syciases sanguineus). This is the second description of a life cycle of a marine digenean from Chile. PMID:25033223

  16. Contrasting soil ciliate species richness and abundance between two tropical plant species: a test of the plant effect.

    PubMed

    Acosta-Mercado, D; Lynn, D H

    2006-05-01

    We still have a rudimentary understanding about the mechanism by which plant roots may stimulate soil microbial interactions. A biochemical model involving plant-derived biochemical fractions, such as exudates, has been used to explain this "rhizosphere effect" on bacteria. However, the variable response of other soil microbial groups, such as protozoa, to the rhizosphere suggests that other factors could be involved in shaping their communities. Thus, two experiments were designed to: (1) determine whether stimulatory and/or inhibiting factors associated with particular plant species regulate ciliate diversity and abundance and (2) obtain a better understanding about the mechanism by which these plant factors operate in the rhizosphere. Bacterial and chemical slurries were reciprocally exchanged between two plant species known to differ in terms of ciliate species richness and abundance (i.e., Canella winterana and plantation Tectona grandis). Analysis of variance showed that the bacteria plus nutrients and the nutrients only treatment had no significant effect on overall ciliate species richness and abundance when compared to the control treatment. However, the use of only colpodean species increased the taxonomic resolution of treatment effects revealing that bacterial slurries had a significant effect on colpodean ciliate species richness. Thus, for particular rhizosphere ciliates, biological properties, such as bacterial diversity or abundance, may have a strong influence on their diversity and possibly abundance. These results are consistent with a model of soil bacteria-mediated mutualisms between plants and protozoa. PMID:16645921

  17. Assessing the sensitivity of avian species abundance to land cover and climate

    USGS Publications Warehouse

    LeBrun, Jaymi J.; Thogmartin, Wayne E.; Thompson, Frank R., III; Dijak, William D.; Millspaugh, Joshua J.

    2016-01-01

    Climate projections for the Midwestern United States predict southerly climates to shift northward. These shifts in climate could alter distributions of species across North America through changes in climate (i.e., temperature and precipitation), or through climate-induced changes on land cover. Our objective was to determine the relative impacts of land cover and climate on the abundance of five bird species in the Central United States that have habitat requirements ranging from grassland and shrubland to forest. We substituted space for time to examine potential impacts of a changing climate by assessing climate and land cover relationships over a broad latitudinal gradient. We found positive and negative relationships of climate and land cover factors with avian abundances. Habitat variables drove patterns of abundance in migratory and resident species, although climate was also influential in predicting abundance for some species occupying more open habitat (i.e., prairie warbler, blue-winged warbler, and northern bobwhite). Abundance of northern bobwhite increased with winter temperature and was the species exhibiting the most significant effect of climate. Models for birds primarily occupying early successional habitats performed better with a combination of habitat and climate variables whereas models of species found in contiguous forest performed best with land cover alone. These varied species-specific responses present unique challenges to land managers trying to balance species conservation over a variety of land covers. Management activities focused on increasing forest cover may play a role in mitigating effects of future climate by providing habitat refugia to species vulnerable to projected changes. Conservation efforts would be best served focusing on areas with high species abundances and an array of habitats. Future work managing forests for resilience and resistance to climate change could benefit species already susceptible to climate impacts.

  18. Spatial covariation of local abundance among different parasite species: the effect of shared hosts.

    PubMed

    Lagrue, C; Poulin, R

    2015-10-01

    Within any parasite species, abundance varies spatially, reaching higher values in certain localities than in others, presumably reflecting the local availability of host resources or the local suitability of habitat characteristics for free-living stages. In the absence of strong interactions between two species of helminths with complex life cycles, we might predict that the degree to which their abundances covary spatially is determined by their common resource requirements, i.e. how many host species they share throughout their life cycles. We test this prediction using five trematode species, all with a typical three-host cycle, from multiple lake sampling sites in New Zealand's South Island: Stegodexamene anguillae, Telogaster opisthorchis, Coitocaecum parvum, Maritrema poulini, and an Apatemon sp. Pairs of species from this set of five share the same host species at either one, two, or all three life cycle stages. Our results show that when two trematode species share the same host species at all three life stages, they show positive spatial covariation in abundance (of metacercarial and adult stages) across localities. When they share hosts at two life stages, they show positive spatial covariation in abundance in some cases but not others. Finally, if two trematode species share only one host species, at a single life stage, their abundances do not covary spatially. These findings indicate that the extent of resource sharing between parasite species can drive the spatial match-mismatch between their abundances, and thus influence their coevolutionary dynamics and the degree to which host populations suffer from additive or synergistic effects of multiple infections. PMID:26113509

  19. Ontogenetic variation in the body stoichiometry of two fish species.

    PubMed

    Boros, Gergely; Sály, Péter; Vanni, Michael J

    2015-10-01

    One of the central questions of ecological stoichiometry theory is to what extent animal species maintain constant elemental composition in their bodies. Although several recent studies demonstrate intraspecific variation in animal elemental composition, relatively little is known about ontogenetic changes in vertebrates, especially during early life stages. We studied the intraspecific and interspecific ontogenetic variation in the body stoichiometry of two fish species in two different orders; fathead minnow (Pimephales promelas) and sheepshead minnow (Cyprinodon variegatus), reared under controlled laboratory conditions. During ontogeny, we measured the chemical composition of fish bodies, including carbon (C), nitrogen (N), phosphorus (P), calcium (Ca), and ribonucleic acid (RNA) contents. We found that N and RNA contents were relatively high in early life stages and declined substantially during development. In contrast, body C and C:N ratios were relatively low in embryos, post-embryos and larvae, and increased remarkably thereafter. Concentrations and ratios of some elements (e.g., Ca, P, Ca:P) did not exhibit consistent ontogenetic trends, but fluctuated dynamically between consecutive developmental stages in both species. Specific growth rates correlated significantly with RNA contents in both species. Analyses of the relative importance of different P pools at each developmental stage revealed that RNA was a considerable P pool in post-embryos, while bone-associated P was the dominant body P pool in later stages. Our results suggest that the elemental composition of fish bodies changes considerably during ontogeny. Each ontogenetic stage has its own stoichiometric signature, but the timing, magnitude and direction of ontogenetic changes can vary substantially between taxa. PMID:25999048

  20. Gradients in the Number of Species at Reef-Seagrass Ecotones Explained by Gradients in Abundance

    PubMed Central

    Tuya, Fernando; Vanderklift, Mathew A.; Wernberg, Thomas; Thomsen, Mads S.

    2011-01-01

    Gradients in the composition and diversity (e.g. number of species) of faunal assemblages are common at ecotones between juxtaposed habitats. Patterns in the number of species, however, can be confounded by patterns in abundance of individuals, because more species tend to be found wherever there are more individuals. We tested whether proximity to reefs influenced patterns in the composition and diversity (‘species density’ = number of species per area and ‘species richness’ = number of species per number of individuals) of prosobranch gastropods in meadows of two seagrasses with different physiognomy: Posidonia and Amphibolis. A change in the species composition was observed from reef-seagrass edges towards the interiors of Amphibolis, but not in Posidonia meadows. Similarly, the abundance of gastropods and species density was higher at edges relative to interiors of Amphibolis meadows, but not in Posidonia meadows. However, species richness was not affected by proximity to reefs in either type of seagrass meadow. The higher number of species at the reef-Amphibolis edge was therefore a consequence of higher abundance, rather than species richness per se. These results suggest that patterns in the composition and diversity of fauna with proximity to adjacent habitats, and the underlying processes that they reflect, likely depend on the physiognomy of the habitat. PMID:21629654

  1. Gradients in the number of species at reef-seagrass ecotones explained by gradients in abundance.

    PubMed

    Tuya, Fernando; Vanderklift, Mathew A; Wernberg, Thomas; Thomsen, Mads S

    2011-01-01

    Gradients in the composition and diversity (e.g. number of species) of faunal assemblages are common at ecotones between juxtaposed habitats. Patterns in the number of species, however, can be confounded by patterns in abundance of individuals, because more species tend to be found wherever there are more individuals. We tested whether proximity to reefs influenced patterns in the composition and diversity ('species density'  =  number of species per area and 'species richness'  =  number of species per number of individuals) of prosobranch gastropods in meadows of two seagrasses with different physiognomy: Posidonia and Amphibolis. A change in the species composition was observed from reef-seagrass edges towards the interiors of Amphibolis, but not in Posidonia meadows. Similarly, the abundance of gastropods and species density was higher at edges relative to interiors of Amphibolis meadows, but not in Posidonia meadows. However, species richness was not affected by proximity to reefs in either type of seagrass meadow. The higher number of species at the reef-Amphibolis edge was therefore a consequence of higher abundance, rather than species richness per se. These results suggest that patterns in the composition and diversity of fauna with proximity to adjacent habitats, and the underlying processes that they reflect, likely depend on the physiognomy of the habitat. PMID:21629654

  2. Remembrance of things past: modelling the relationship between species' abundances in living communities and death assemblages.

    PubMed

    Olszewski, Thomas D

    2012-02-23

    Accumulations of dead skeletal material are a valuable archive of past ecological conditions. However, such assemblages are not equivalent to living communities because they mix the remains of multiple generations and are altered by post-mortem processes. The abundance of a species in a death assemblage can be quantitatively modelled by successively integrating the product of an influx time series and a post-mortem loss function (a decay function with a constant half-life). In such a model, temporal mixing increases expected absolute dead abundance relative to average influx as a linear function of half-life and increases variation in absolute dead abundance values as a square-root function of half-life. Because typical abundance distributions of ecological communities are logarithmically distributed, species' differences in preservational half-life would have to be very large to substantially alter species' abundance ranks (i.e. make rare species common or vice-versa). In addition, expected dead abundances increase at a faster rate than their range of variation with increased time averaging, predicting greater consistency in the relative abundance structure of death assemblages than their parent living community. PMID:21653564

  3. Long-term changes in species composition and relative abundances of sharks at a provisioning site.

    PubMed

    Brunnschweiler, Juerg M; Abrantes, Kátya G; Barnett, Adam

    2014-01-01

    Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today's recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-species shark feeding site in Fiji. Using direct observation sampling methods, eight species of sharks (bull shark Carcharhinus leucas, grey reef shark Carcharhinus amblyrhynchos, whitetip reef shark Triaenodon obesus, blacktip reef shark Carcharhinus melanopterus, tawny nurse shark Nebrius ferrugineus, silvertip shark Carcharhinus albimarginatus, sicklefin lemon shark Negaprion acutidens, and tiger shark Galeocerdo cuvier) displayed inter-annual site fidelity between 2003 and 2012. Encounter rates and/or relative abundances of some species changed over time, overall resulting in more individuals (mostly C. leucas) of fewer species being encountered on average on shark feeding dives at the end of the study period. Differences in shark community composition between the years 2004-2006 and 2007-2012 were evident, mostly because N. ferrugineus, C. albimarginatus and N. acutidens were much more abundant in 2004-2006 and very rare in the period of 2007-2012. Two explanations are offered for the observed changes in relative abundances over time, namely inter-specific interactions and operator-specific feeding protocols. Both, possibly in combination, are suggested to be important determinants of species composition and encounter rates, and relative abundances at this shark provisioning site in Fiji. This study, which includes the most species from a spatially confined shark provisioning site to date, suggests that long-term provisioning may result in competitive exclusion among shark

  4. Long-Term Changes in Species Composition and Relative Abundances of Sharks at a Provisioning Site

    PubMed Central

    Brunnschweiler, Juerg M.; Abrantes, Kátya G.; Barnett, Adam

    2014-01-01

    Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today’s recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-species shark feeding site in Fiji. Using direct observation sampling methods, eight species of sharks (bull shark Carcharhinus leucas, grey reef shark Carcharhinus amblyrhynchos, whitetip reef shark Triaenodon obesus, blacktip reef shark Carcharhinus melanopterus, tawny nurse shark Nebrius ferrugineus, silvertip shark Carcharhinus albimarginatus, sicklefin lemon shark Negaprion acutidens, and tiger shark Galeocerdo cuvier) displayed inter-annual site fidelity between 2003 and 2012. Encounter rates and/or relative abundances of some species changed over time, overall resulting in more individuals (mostly C. leucas) of fewer species being encountered on average on shark feeding dives at the end of the study period. Differences in shark community composition between the years 2004–2006 and 2007–2012 were evident, mostly because N. ferrugineus, C. albimarginatus and N. acutidens were much more abundant in 2004–2006 and very rare in the period of 2007–2012. Two explanations are offered for the observed changes in relative abundances over time, namely inter-specific interactions and operator-specific feeding protocols. Both, possibly in combination, are suggested to be important determinants of species composition and encounter rates, and relative abundances at this shark provisioning site in Fiji. This study, which includes the most species from a spatially confined shark provisioning site to date, suggests that long-term provisioning may result in competitive exclusion

  5. Regional species richness of families and the distribution of abundance and rarity in a local community of forest Hymenoptera

    NASA Astrophysics Data System (ADS)

    Ulrich, Werner

    2005-09-01

    Recent investigations about the relationship between the number of species of taxonomic lineages and regional patterns of species abundances gave indecisive results. Here, it is shown that mean densities of species of a species-rich community of forest Hymenoptera (673 species out of 25 families) were positively related to the number of European species per family. The fraction of abundant species per family declined and the fraction of rare species increased with species richness. Species rich families contained relatively more species, which were present in only one study year (occasional species), and relatively fewer species present during the whole study period (frequent species).

  6. Patterns in the abundance and size-distribution of syngnathid fishes among habitats in a seagrass-dominated marine environment

    NASA Astrophysics Data System (ADS)

    Kendrick, A. J.; Hyndes, G. A.

    2003-07-01

    Syngnathid fishes were sampled using a 1 m wide beam trawl during the day and night in each season from summer 1996/1997 to summer 1997/1998 in five habitat types in an approximately 90 km 2 area located on the lower west coast of Australia. The seagrasses Amphibolis griffithii, Posidonia sinuosa and Posidonia coriacea and shallow unvegetated sand were all in depths of 4-9 m, while deep habitat, which comprised mainly bare sand with isolated patches of the seagrasses Heterozostera tasmanica and Halophila ovalis, occurred at depths of 12-16 m. While A. griffithii and P. sinuosa each formed dense monospecific meadows, P. coriacea occurred in sparse clumps surrounded by areas of bare sand and patches of H. tasmanica. While catches of spotted pipefish Stigmatopora argus occurred mainly in P. sinuosa and P. coriacea, individuals of this species that exceeded ca. 55 mm in snout-vent length were far more abundant in the former habitat whereas smaller fish occurred mostly in the latter. Densities of S. argus were similar in P. sinuosa and P. coriacea, but differed between seasons, and a season/habitat interaction was present. In contrast, wide-bodied pipefish Stigmatopora nigra were collected mainly in P. coriacea and deep habitat and, although the densities were greater in P. coriacea than in deep habitat, the size-distributions of this species in these habitats were similar. Notably, S. nigra was never collected in P. sinuosa. Although less abundant than the above pipefish, the long-snouted pipefish Vanacampus poecilolaemus was collected almost exclusively in P. sinuosa. Few syngnathids were collected from shallow unvegetated sand or from A. griffithii, which differed markedly in plant structure from both Posidonia species. It is suggested that these syngnathid species occupy habitats that best enable them to remain inconspicuous to predators. Both S. argus and S. nigra have green or brown colouration and mimic strap-like seagrass leaves which they grasp with prehensile

  7. Dramatic increase in the relative abundance of large male dungeness crabs Cancer magister following closure of commercial fishing in Glacier Bay, Alaska

    USGS Publications Warehouse

    Taggart, S.J.; Shirley, T.C.; O'Clair, C. E.; Mondragon, J.

    2004-01-01

    The size structure of the population of the Dungeness crab Cancer magister was studied at six sites in or near Glacier Bay, Alaska, before and after the closure of commercial fishing. Seven years of preclosure and 4 years of postclosure data are presented. After the closure of Glacier Bay to commercial fishing, the number and size of legal-sized male Dungeness crabs increased dramatically at the experimental sites. Female and sublegal-sized male crabs, the portions of the population not directly targeted by commercial fishing, did not increase in size or abundance following the closure. There was not a large shift in the size-abundance distribution of male crabs at the control site that is still open to commercial fishing. Marine protected areas are being widely promoted as effective tools for managing fisheries while simultaneously meeting marine conservation goals and maintaining marine biodiversity. Our data demonstrate that the size of male Dungeness crabs can markedly increase in a marine reserve, which supports the concept that marine reserves could help maintain genetic diversity in Dungeness crabs and other crab species subjected to size-limit fisheries and possibly increase the fertility of females. ?? 2004 by the American Fisheries Society.

  8. Species-specific patterns of hyperostosis in marine teleost fishes

    USGS Publications Warehouse

    Smith-Vaniz, William F.; Kaufman, L.S.; Glowacki, J.

    1995-01-01

    The occurrence of swollen or hyperostotic bones in skeletal preparations, preserved museum material or whole fresh specimens of marine teleost fishes was identified in 92 species belonging to 22 families. Patterns of hyperostotic skeletal growth were typically consistent and often species-specific in all individuals larger than a certain size. The taxonomic distribution of hyperostosis in diverse phylogenetic groups suggests that it has arisen independently many times. Selected bones from two species of the family Carangidae, horse-eye jack Caranx latus Agassiz and crevalle jackCaranx hippos (Linnaeus), were examined in detail by light and electron microscopy. Nonhyperostotic bone contained osteoid-producing osteoblasts, resorbing osteoclasts, occasional osteocytes, and a rich vascular network, all characteristics of cellular bone. Thus, these fishes have a spatial juxtaposition of cellular and acellular bone tissues in adjacent and often serially homologous bone sites. The functional significance of hyperostosis is unknown, but it is a predictable manifestation of bone growth and development for the many taxa in which it occurs.

  9. Regional-scale directional changes in abundance of tree species along a temperature gradient in Japan.

    PubMed

    Suzuki, Satoshi N; Ishihara, Masae I; Hidaka, Amane

    2015-09-01

    Climate changes are assumed to shift the ranges of tree species and forest biomes. Such range shifts result from changes in abundances of tree species or functional types. Owing to global warming, the abundance of a tree species or functional type is expected to increase near the colder edge of its range and decrease near the warmer edge. This study examined directional changes in abundance and demographic parameters of forest trees along a temperature gradient, as well as a successional gradient, in Japan. Changes in the relative abundance of each of four functional types (evergreen broad-leaved, deciduous broad-leaved, evergreen temperate conifer, and evergreen boreal conifer) and the demography of each species (recruitment rate, mortality, and population growth rate) were analyzed in 39 permanent forest plots across the Japanese archipelago. Directional changes in the relative abundance of functional types were detected along the temperature gradient. Relative abundance of evergreen broad-leaved trees increased near their colder range boundaries, especially in secondary forests, coinciding with the decrease in deciduous broad-leaved trees. Similarly, relative abundance of deciduous broad-leaved trees increased near their colder range boundaries, coinciding with the decrease in boreal conifers. These functional-type-level changes were mainly due to higher recruitment rates and partly to the lower mortality of individual species at colder sites. This is the first report to show that tree species abundances in temperate forests are changing directionally along a temperature gradient, which might be due to current or past climate changes as well as recovery from past disturbances. PMID:25712048

  10. Lipid content and fatty acid composition of 11 species of Queensland (Australia) fish.

    PubMed

    Belling, G B; Abbey, M; Campbell, J H; Campbell, G R

    1997-06-01

    The fatty acid composition of 11 species of fish caught of the northeast coast of Australia was determined. No fatty acid profiles have been previously published for fish from this area nor for nine of these species. Although the percentage of polyunsaturated fatty acid (PUFA) was the same as the calculated average for Australian fish (42.3%), the percentage of n-3 fatty acids was lower (24.4 +/- 5.4% vs. 30.7 +/- 10.1%) and the n-6 fatty acids higher (16.5 +/- 4.5% vs. 11.2 +/- 5.9%), P < 0.001 in each case. The major n-3 PUFA were docosahexaenoic (15.6 +/- 6.3%) and eicosapentaenoic acid (4.3 +/- 1.1%) while the major n-6 PUFA were arachidonic (8.3 +/- 3.2%) and n-6 docosatetraenoic acid (3.1 +/- 1.3%). The second-most abundant class of fatty acid was the saturates (31.6 +/- 3.5%) while the monounsaturates accounted for 17.4 +/- 4.3% of the total fatty acids. The monounsaturate with the highest concentration was octadecenoic acid (11.8 +/- 2.6%). There was a positive correlation between the total lipid content and saturated and monounsaturated fatty acids (r = 0.675 and 0.567, respectively) and a negative correlation between the total lipid content and PUFA (r = 0.774). PMID:9208391

  11. Effect of outflow on spring and summertime distribution and abundance of larval and juvenile fishes in the upper San Francisco Estuary

    USGS Publications Warehouse

    Dege, M.; Brown, L.R.

    2004-01-01

    We analyzed data on spring and summertime larval and juvenile fish distribution and abundance in the upper San Francisco Estuary (SFE), California between 1995 and 2001. The upper SFE includes the tidal freshwater areas of the Sacramento-San Joaquin Delta downstream to the euryhaline environment of San Pablo Bay. The sampling period included years with a variety of outflow conditions. Fifty taxa were collected using a larval tow net. Two common native species, delta smelt Hypomesus transpacifucus and longfin smelt Spirinchus thaleichthys, and four common alien taxa, striped bass Morone saxatilis, threadfin shad Dorosoma petenense, gobies of the genus Tridentiger, and yellowfin goby Acanthogobins flavimanus, were selected for detailed analysis. Outflow conditions had a strong influence on the geographic distribution of most of the species, but distribution with respect to the 2 psu isohaline (X2) was not affected. The distribution patterns of delta smelt, longfin smelt, and striped bass were consistent with larvae moving from upstream freshwater spawning areas to down-stream estuarine rearing areas. There were no obvious relationships of outflow with annual abundance indices. Our results support the idea of using X2 as an organizing principle in understanding the ecology of larval fishes in the upper SFE. Additional years of sampling will likely lead to additional insights into the early life history of upper SFE fishes. ?? Copyright by the American Fisheries Society 2004.

  12. Using hierarchical Bayesian multi-species mixture models to estimate tandem hoop-net based habitat associations and detection probabilities of fishes in reservoirs

    USGS Publications Warehouse

    Stewart, David R.; Long, James M.

    2015-01-01

    Species distribution models are useful tools to evaluate habitat relationships of fishes. We used hierarchical Bayesian multispecies mixture models to evaluate the relationships of both detection and abundance with habitat of reservoir fishes caught using tandem hoop nets. A total of 7,212 fish from 12 species were captured, and the majority of the catch was composed of Channel Catfish Ictalurus punctatus (46%), Bluegill Lepomis macrochirus(25%), and White Crappie Pomoxis annularis (14%). Detection estimates ranged from 8% to 69%, and modeling results suggested that fishes were primarily influenced by reservoir size and context, water clarity and temperature, and land-use types. Species were differentially abundant within and among habitat types, and some fishes were found to be more abundant in turbid, less impacted (e.g., by urbanization and agriculture) reservoirs with longer shoreline lengths; whereas, other species were found more often in clear, nutrient-rich impoundments that had generally shorter shoreline length and were surrounded by a higher percentage of agricultural land. Our results demonstrated that habitat and reservoir characteristics may differentially benefit species and assemblage structure. This study provides a useful framework for evaluating capture efficiency for not only hoop nets but other gear types used to sample fishes in reservoirs.

  13. Spatial, Temporal, and Habitat-Related Variation in Abundance of Pelagic Fishes in the Gulf of Mexico: Potential Implications of the Deepwater Horizon Oil Spill

    PubMed Central

    Rooker, Jay R.; Kitchens, Larissa L.; Dance, Michael A.; Wells, R. J. David; Falterman, Brett; Cornic, Maëlle

    2013-01-01

    Time-series data collected over a four-year period were used to characterize patterns of abundance for pelagic fishes in the northern Gulf of Mexico (GoM) before (2007–2009) and after (2010) the Deepwater Horizon oil spill. Four numerically dominant pelagic species (blackfin tuna, blue marlin, dolphinfish, and sailfish) were included in our assessment, and larval density of each species was lower in 2010 than any of the three years prior to the oil spill, although larval abundance in 2010 was often statistically similar to other years surveyed. To assess potential overlap between suitable habitat of pelagic fish larvae and surface oil, generalized additive models (GAMs) were developed to evaluate the influence of ocean conditions on the abundance of larvae from 2007–2009. Explanatory variables from GAMs were then linked to environmental data from 2010 to predict the probability of occurrence for each species. The spatial extent of surface oil overlapped with early life habitat of each species, possibly indicating that the availability of high quality habitat was affected by the DH oil spill. Shifts in the distribution of spawning adults is another factor known to influence the abundance of larvae, and the spatial occurrence of a model pelagic predator (blue marlin) was characterized over the same four-year period using electronic tags. The spatial extent of oil coincided with areas used by adult blue marlin from 2007–2009, and the occurrence of blue marlin in areas impacted by the DH oil spill was lower in 2010 relative to pre-spill years. PMID:24130759

  14. DNA barcoding and microsatellites help species delimitation and hybrid identification in endangered galaxiid fishes.

    PubMed

    Vanhaecke, Delphine; Garcia de Leaniz, Carlos; Gajardo, Gonzalo; Young, Kyle; Sanzana, Jose; Orellana, Gabriel; Fowler, Daniel; Howes, Paul; Monzon-Arguello, Catalina; Consuegra, Sofia

    2012-01-01

    The conservation of data deficient species is often hampered by inaccurate species delimitation. The galaxiid fishes Aplochiton zebra and Aplochiton taeniatus are endemic to Patagonia (and for A. zebra the Falkland Islands), where they are threatened by invasive salmonids. Conservation of Aplochiton is complicated because species identification is hampered by the presence of resident as well as migratory ecotypes that may confound morphological discrimination. We used DNA barcoding (COI, cytochrome b) and a new developed set of microsatellite markers to investigate the relationships between A. zebra and A. taeniatus and to assess their distributions and relative abundances in Chilean Patagonia and the Falkland Islands. Results from both DNA markers were 100% congruent and revealed that phenotypic misidentification was widespread, size-dependent, and highly asymmetric. While all the genetically classified A. zebra were correctly identified as such, 74% of A. taeniatus were incorrectly identified as A. zebra, the former species being more widespread than previously thought. Our results reveal, for the first time, the presence in sympatry of both species, not only in Chilean Patagonia, but also in the Falkland Islands, where A. taeniatus had not been previously described. We also found evidence of asymmetric hybridisation between female A. taeniatus and male A. zebra in areas where invasive salmonids have become widespread. Given the potential consequences that species misidentification and hybridisation can have for the conservation of these endangered species, we advocate the use of molecular markers in order to reduce epistemic uncertainty. PMID:22412956

  15. DNA Barcoding and Microsatellites Help Species Delimitation and Hybrid Identification in Endangered Galaxiid Fishes

    PubMed Central

    Vanhaecke, Delphine; Garcia de Leaniz, Carlos; Gajardo, Gonzalo; Young, Kyle; Sanzana, Jose; Orellana, Gabriel; Fowler, Daniel; Howes, Paul; Monzon-Arguello, Catalina; Consuegra, Sofia

    2012-01-01

    The conservation of data deficient species is often hampered by inaccurate species delimitation. The galaxiid fishes Aplochiton zebra and Aplochiton taeniatus are endemic to Patagonia (and for A. zebra the Falkland Islands), where they are threatened by invasive salmonids. Conservation of Aplochiton is complicated because species identification is hampered by the presence of resident as well as migratory ecotypes that may confound morphological discrimination. We used DNA barcoding (COI, cytochrome b) and a new developed set of microsatellite markers to investigate the relationships between A. zebra and A. taeniatus and to assess their distributions and relative abundances in Chilean Patagonia and the Falkland Islands. Results from both DNA markers were 100% congruent and revealed that phenotypic misidentification was widespread, size-dependent, and highly asymmetric. While all the genetically classified A. zebra were correctly identified as such, 74% of A. taeniatus were incorrectly identified as A. zebra, the former species being more widespread than previously thought. Our results reveal, for the first time, the presence in sympatry of both species, not only in Chilean Patagonia, but also in the Falkland Islands, where A. taeniatus had not been previously described. We also found evidence of asymmetric hybridisation between female A. taeniatus and male A. zebra in areas where invasive salmonids have become widespread. Given the potential consequences that species misidentification and hybridisation can have for the conservation of these endangered species, we advocate the use of molecular markers in order to reduce epistemic uncertainty. PMID:22412956

  16. Abundance, Distribution and Estimated Consumption (kg fish) of Piscivorous Birds Along the Yakima River, Washington State; Implications for Fisheries Management, 2002 Annual Report.

    SciTech Connect

    Major, III, Walter; Grassley, James M.; Ryding, Kristen E.

    2003-05-01

    This report is divided into two chapters. The abstract for chapter one is--Understanding of the abundance and spatial and temporal distributions of piscivorous birds and their potential consumption of fish is an increasingly important aspect of fisheries management. During 1999-2002, we determined the abundance and distribution and estimated the maximum consumption (kg biomass) of fish-eating birds along the length of the Yakima River in Washington State. Sixteen different species were observed during the 4-yr study, but only half of those were observed during all years. Abundance and estimated consumption of fish within the upper and middle sections of the river were dominated by common mergansers (Mergus merganser) which are known to breed in those reaches. Common mergansers accounted for 78 to 94% of the estimated total fish take for the upper river or approximately 28,383 {+-} 1,041 kg over the 4 yrs. A greater diversity of avian piscivores occurred in the lower river and potential impacts to fish populations was more evenly distributed among the species. In 1999-2000, great blue herons potentially accounted for 29 and 36% of the fish consumed, whereas in 2001-2002 American white pelicans accounted for 53 and 55%. We estimated that approximately 75,878 {+-} 6,616 kg of fish were consumed by piscivorous birds in the lower sections of the river during the study. Bird assemblages differed spatially along the river with a greater abundance of colonial nesting species within the lower sections of the river, especially during spring and the nesting season. The abundance of avian piscivores and consumption estimates are discussed within the context of salmonid supplementation efforts on the river and juvenile out-migration. The abstract for chapter two is--Consumption of fish by piscivorous birds may be a significant constraint on efforts to enhance salmonid populations within tributaries to the Columbia River in Washington State. During 1999-2002, we determined the

  17. 76 FR 14923 - Endangered and Threatened Species; Take of Anadromous Fish

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-18

    ... Anadromous Fish AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric.... seq) and regulations governing listed fish and wildlife permits (50 CFR parts 222-226). NMFS issues... groundfish species. The survey would collect data on 90+ fish species in the ocean to fulfill the mandates...

  18. Pacific herring: Species profiles, life histories and environmental requirements of coastal fishes and invertebrates (Pacific Southwest)

    SciTech Connect

    Barnhart, R.A.

    1988-02-01

    Species profiles are literature summaries of the taxonomy, morphology, distribution, life history, and environmental requirements of coastal aquatic species. They are prepared to assist in environmental impact assessment. The Pacific herring, Clupea harengus pallasi, spawns in intertidal and subtidal waters of the Pacific coast during the winter-spring season. In California, female herring average about 220 eggs per gram body weight. Herring are fished commercially primarily during the spawning season to obtain herring roe for export to Japan. Herring have a significant ecological role; herring spawn deposits attract many predators, and the abundant herring larvae and juveniles found in estuaries and nearshore waters serve as food for larger sea life. Herring embryos and larvae are fairly plastic regarding temperature and salinity, and survival probably depends largely on extent of predation and food supply. Excessive turbidity hinders the spawning and incubation of herring. Herring embryos, larvae, and juveniles are subject to various pollutants introduced into the estuarine environment. 60 refs., 4 figs.

  19. Relative abundance and distribution of fishes and crayfish at Ash Meadows National Wildlife Refuge, Nye County, Nevada, 2007-08

    USGS Publications Warehouse

    Scoppettone, G. Gary; Rissler, Peter; Johnson, Danielle; Hereford, Mark

    2011-01-01

    swamp crayfish and western mosquitofish was in water with temperature greater than 26 degrees C near the springhead, and in shallow (depths less than 10 centimeters) grassy marshes. Among 177 sampling stations within the range of Warm Springs Amargosa pupfish, red swamp crayfish were collected at 96 stations and western mosquitofish were collected at 49 stations. Removal of convict cichlid (Amatitlania nigrofasciata) from Fairbanks Spring was followed by a substantial increase in Ash Meadows Amargosa pupfish (Cyprinodon nevadensis mionectes) captures from 910 pre-removal to 3,056 post-removal. Red swamp crayfish was continually removed from Bradford 1 Spring, which seemed to cause an increase in the speckled dace population. Restoration of Kings Pool and Jackrabbit Springs promoted the success of native fishes with the greatest densities in restored reaches. Ongoing restoration of Carson Slough and its tributaries, as well as control and elimination of invasive species, is expected to increase abundance and distribution of Ash Meadows' native fish populations. Further analysis of data from this study will help determine the habitat characteristic(s) that promote native species and curtail non-native species.

  20. Three unrecorded marine fish species from Korean waters

    NASA Astrophysics Data System (ADS)

    Park, Jeong-Ho; Kim, Jin Koo; Moon, Jee Hwan; Kim, Cheol Bum

    2007-12-01

    Three marine fish species are recorded for the first time from Korean waters: a molid (Ranzania laevis, 1 specimen, 279.8 mm SL) and bramid ( Pterycombus petersii, 3 specimens, 95.3-214.0 mm SL) collected from a large purse seine off Jeju Island, in the southern sea of Korea, and a carangid ( Carangoides dinema, 1 specimen, 194.5 mm SL) from a set net in coastal waters off Busan, in the southeastern sea of Korea. R. laevis is characterized by a wedge-shaped body and truncated clavus; P. petersii by the dorsal fin origin above or behind the posterior margin of eye, and dorsal and anal fins depressible; and C. dinema by a row of black blotches along the second dorsal fin base, the curved part of the lateral line longer than straight part, and 18 and 16 dorsal and anal fin rays, respectively. New Korean names are proposed for all three species.

  1. Early MESSENGER Results for Less Abundant or Weakly Emitting Species in Mercury's Exosphere

    NASA Technical Reports Server (NTRS)

    Vervack, Ronald J., Jr.; McClintock, William E.; Killen, Rosemary M.; Sprague, Ann L.; Burger, Matthew H.; Merkel, Aimee W.; Sarantos, Menelaos

    2011-01-01

    Now that the Messenger spacecraft is in orbit about Mercury, the extended observing time enables searches for exospheric species that are less abundant or weakly emitting compared with those for which emission has previously been detected. Many of these species cannot be observed from the ground because of terrestrial atmospheric absorption. We report here on the status of MESSENGER orbital-phase searches for additional species in Mercury's exosphere.

  2. Early MESSENGER Results for Less Abundant or Weakly Emitting Species in Mercury's Exosphere

    NASA Astrophysics Data System (ADS)

    Vervack, R. J., Jr.; Killen, R. M.; Sprague, A. L.; Burger, M. H.; Merkel, A. W.; Sarantos, M.

    2011-10-01

    Now that the MESSENGER spacecraft is in orbit about Mercury, the extended observing time enables searches for exospheric species that are less abundant or weakly emitting compared with those for which emission has previously been detected. Many of these species cannot be observed from the ground because of terrestrial atmospheric absorption. We report here on the status of MESSENGER orbitalphase searches for additional species in Mercury's exosphere.

  3. Abundance, diversity, and resource use in an assemblage of Conus species in Enewetak lagoon

    SciTech Connect

    Kohn, A.J.

    1980-10-01

    Eight species of the gastropod genus Conus co-occur in sand substrate and an adjacent meadow of Halimeda stuposa in Enewetak lagoon, an unusually diverse assemblage for this type of habitat. Population density is high, and large species predominate; they represent all major feeding groups in the genus: predators on polychaetes, enteropneusts, gastropods, and fishes. Although the two most common Conus species eat primarily the same prey species, they mainly take prey of different sizes in different microhabitats. The results suggest that sufficient microhabitat heterogeneity and prey diversity exist to permit spatial segregation and specialization on different prey resources by the different Conus species present. Between-species dissimilarity in resource use thus agrees with previous observations on more diverse Conus assemblages of subtidal coral reef platforms. Prey species diversity is inversely related to body size, confirming and extending a previously identified pattern among Conus species that prey on sedentary polychaetes.

  4. Decadal variability in abundances of the dominant euphausiid species in southern sectors of the California Current

    NASA Astrophysics Data System (ADS)

    Brinton, Edward; Townsend, Annie

    2003-08-01

    Euphausiid abundance data from broadly based California Cooperative Oceanic Fisheries Investigation surveys in California and Baja California sectors of the California Current provided a time series distinguishing periodic, rhythmic and irregular species patterns. Comparisons with environmental indexes indicate significant correlations with warm-water species, most notably in coastal Nyctiphanes simplex. Oceanic warm-water species were similarly, but less extremely, allied with an index. Coastal warm-water N. simplex was uncommon off southern California before the atmospheric regime shift of the 1970s. It assumed a post-1978 pattern of rhythmic biannual abundance increases and decreases during 1981-2000. The near-tropical oceanic Euphausia eximia and Pacific Central subtropicals patterned similarly, but was more periodic than rhythmic. Euphausia pacifica, the most dominant and broadly ranging Euphausia species, peaked at irregular but distinct bi-decadal abundances during 6 strong La Niña episodes. The peaks uniformly collapsed by 90%, becoming El Niño-associated minima. The cold-water coastal northern species Thysanoessa spinifera frequently ranged far south off Baja California before 1960 but became limited to Central California in the 1980s. The importance of T. spinifera off the Californias is small compared with northern regions, but it extends to southern upwelling centers contributing to dominance, here, by cold-water euphausiids. Decadal periodicity of species abundances decreased in the 1990s, when trends became more common. Differences among sectors were minimal between the two Californias, but were often distinct between southern California and Central Baja California. Species abundances, comparing pre- and post-climate shift species averages, differed insignificantly for all species when logarithmic values were used. With arithmetic values, most 1977-1998 average values were the greater, but with large standard deviations.

  5. Global patterns in sandy beach macrofauna: Species richness, abundance, biomass and body size

    NASA Astrophysics Data System (ADS)

    Defeo, Omar; McLachlan, Anton

    2013-10-01

    Global patterns in species richness in sandy beach ecosystems have been poorly understood until comparatively recently, because of the difficulty of compiling high-resolution databases at continental scales. We analyze information from more than 200 sandy beaches around the world, which harbor hundreds of macrofauna species, and explore latitudinal trends in species richness, abundance and biomass. Species richness increases from temperate to tropical sites. Abundance follows contrasting trends depending on the slope of the beach: in gentle slope beaches, it is higher at temperate sites, whereas in steep-slope beaches it is higher at the tropics. Biomass follows identical negative trends for both climatic regions at the whole range of beach slopes, suggesting decreasing rates in carrying capacity of the environment towards reflective beaches. Various morphodynamic variables determine global trends in beach macrofauna. Species richness, abundance and biomass are higher at dissipative than at reflective beaches, whereas a body size follows the reverse pattern. A generalized linear model showed that large tidal range (which determines the vertical dimension of the intertidal habitat), small size of sand particles and flat beach slope (a product of the interaction among wave energy, tidal range and grain size) are correlated with high species richness, suggesting that these parameters represent the most parsimonious variables for modelling patterns in sandy beach macrofauna. Large-scale patterns indicate a scaling of abundance to a body size, suggesting that dissipative beaches harbor communities with highest abundance and species with the smallest body sizes. Additional information for tropical and northern hemisphere sandy beaches (underrepresented in our compilation) is required to decipher more conclusive trends, particularly in abundance, biomass and body size. Further research should integrate meaningful oceanographic variables, such as temperature and primary

  6. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Northwest): Pink salmon

    SciTech Connect

    Bonar, S.A.; Pauley, G.B.; Thomas, G.L.

    1989-01-01

    Species profiles are literature summaries of the taxonomy, morphology, range, life history, and environmental requirements of coastal aquatic species. They are designed to assist in environmental impact assessment. The pink salmon, often called humpback salmon or humpy, is easily identified by its extremely small scales (150 to 205) on the lateral line. They are the most abundant of the Pacific salmon species and spawn in North American and Asian streams bordering the Pacific and Arctic Oceans. They have a very simple two-year life cycle, which is so invariable that fish running in odd-numbered years are isolated from fish running in even-numbered years so that no gene flow occurs between them. Adults spawn in the fall and the young fry emerge in the spring. The pink salmon is less desirable in commercial and sport catches than most other salmon because of its small size and its soft pale flesh. The Puget Sound region of Washington State is the southern geographic limit of streams supporting major pink salmon runs in the eastern North Pacific. Pink salmon runs are presently only in odd-numbered years in this region. Optimum water temperatures for spawning range from 7.2 to 12.8/degree/C. Productive pink salmon streams have less than 5.0% by volume of fine sediments (less than or equal to0.8 mm). 87 refs., 5 figs., 1 tab.

  7. Variation in heat shock proteins within tropical and desert species of poeciliid fishes.

    PubMed

    Norris, C E; diIorio, P J; Schultz, R J; Hightower, L E

    1995-11-01

    The 70-kilodalton heat shock protein (hsp70) family of molecular chaperones, which contains both stress-inducible and normally abundant constitutive members, is highly conserved across distantly related taxa. Analysis of this protein family in individuals from an outbred population of tropical topminnows, Poeciliopsis gracilis, showed that while constitutive hsp70 family members showed no variation in protein isoforms, inducibly synthesized hsp70 was polymorphic. Several species of Poeciliopsis adapted to desert environments exhibited lower levels of inducible hsp70 polymorphism than the tropical species, but constitutive forms were identical to those in P. gracilis, as they were in the confamilial species Gambusia affinis. These differences suggest that inducible and constitutive members of this family are under different evolutionary constraints and may indicate differences in their function within the cell. Also, northern desert species of Poeciliopsis synthesize a subset of the inducible hsp70 isoforms seen in tropical species. This distribution supports the theory that ancestral tropical fish migrated northward and colonized desert streams; the subsequent decrease in variation of inducible hsp70 may have been due to genetic drift or a consequence of adaptation to the desert environment. Higher levels of variability were found when the 30-kilodalton heat shock protein (hsp30) family was analyzed within different strains of two desert species of Poeciliopsis and also in wild-caught individuals of Gambusia affinis. In both cases the distribution of hsp30 isoform diversity was similar to that seen previously with allozyme polymorphisms. PMID:8524039

  8. Copepod abundance and species composition in the Eastern subtropical/tropical Atlantic

    NASA Astrophysics Data System (ADS)

    Schnack-Schiel, Sigrid B.; Mizdalski, Elke; Cornils, Astrid

    2010-12-01

    Abundance and species composition of copepods were studied during the expedition ANT XXI/1 on a latitudinal transect in the eastern Atlantic from 34°49.5'N to 27°28.1'S between 2-20 November 2002. Stratified zooplankton tows were carried out at 19 stations with a multiple opening-closing net between 300 m water depth and the surface. Cyclopoid and calanoid copepods showed similar patterns of distribution and abundance. Oithona was the most abundant cyclopoid genus, followed by Oncaea. A total of 149 calanoid copepod species were identified. Clausocalanus was by far the most abundant genus, comprising on average about 45% of all calanoids, followed by Calocalanus (13%), Delibus (9%), Paracalanus (6%), and Pleuromamma (5%). All other genera comprised on average less than 5% each, with 40 genera less than 1%. The calanoid copepod communities were distinguished broadly in accordance with sea surface temperature, separating the subtropical from the tropical stations, and were largely determined by variation in species composition and species abundance. Nine Clausocalanus species were identified. The most numerous Clausocalanus species was C. furcatus, which on average comprised half of all adult of this genus. C. pergens, C. paululus, and C. jobei, contributed an average of 19%, 9%, and 9%, respectively. The Clausocalanus species differed markedly in their horizontal and vertical distributions: C. furcatus, C. jobei, and C. mastigophorus had widespread distributions and inhabited the upper water layers. Major differences between the species were found in abundance. C. paululus and C. arcuicornis were biantitropical and were absent or occurred in very low numbers in the equatorial zone. C. parapergens was found at all stations and showed a bimodal distribution pattern with maxima in the subtropics. C. pergens occurred in higher numbers only at the southern stations, where it replaced C. furcatus in dominance. In contrast to the widespread species, the bulk of the C

  9. Predator driven diel variation in abundance and behaviour of fish in deep and shallow habitats of an estuary

    NASA Astrophysics Data System (ADS)

    Becker, Alistair; Suthers, Iain M.

    2014-05-01

    Our traditional understanding of the behaviour of large predatory fish and their smaller prey in estuarine ecosystems is often restricted by different gear types and visibility. In this study we determined the diel distribution and inferred movements of fish in an estuary in shallow and deep habitats (<1 m and 4 m deep respectively), using an unbaited acoustic camera (DIDSON). Baitfish (<100 mm TL) formed small and large shoals during the day in both shallow and deep habitats, compared to loose aggregations during the night or when they were inactive and not observed. Three larger size classes of fish (small, 100-300 mm Total Length (TL); medium, 301-500 mm TL and large >500 mm TL) were also more abundant during the day, likely due to general higher activity. This coincided with predatory activity with attacks by larger fish (301-500 mm and >500 mm) witnessed during the day but not at night. This heightened activity is the likely cause for changes in the schooling behaviour of the baitfish. The proportion of medium and large fish in the shallow habitat at night increased by over 50% as they moved from deeper areas of the estuary, showing the abundance of large predators in shallow water can be related to diel period. This highlights the pervasive top down influence even small numbers of predators can exert on the behaviour and distribution of estuarine fish assemblages.

  10. Horizontal Trends in Larval Fish Diversity and Abundance Along an Ocean-Estuarine Gradient on the Northern KwaZulu-Natal Coast, South Africa

    NASA Astrophysics Data System (ADS)

    Harris, S. A.; Cyrus, D. P.; Beckley, L. E.

    2001-08-01

    The structure of the larval fish assemblages along an ocean-estuarine gradient in the St Lucia region on the northern KwaZulu-Natal coast of South Africa was examined using a combination of univariate, distributional and multivariate techniques. The data was comprised of a full annual set of ichthyoplankton samples taken from three types of environment: nearshore coastal waters, surf zone and within the St Lucia Estuary itself. The mean monthly densities of each species in each environment were used in the species matrix, and the mean monthly values of salinity, temperature and turbidity were used in the physical variables matrix. The mean species diversity and eveness index was significantly higher in the nearshore waters than the surf zone and estuary. The patterns of relative species abundances in each environment (K-dominance curves) showed that the estuarine environment was dominated by a few species in large numbers, the surf zone was intermediate, and the nearshore coast was the most diverse. Classification and multidimensional scaling (MDS) ordination analyses of larval fish densities grouped together into three main clusters based on the three different environments. The species similarity matrix (inverse analysis) clustered into four groups at the 10% similarity level. The MDS analysis of the same matrix showed that the groups separated out more or less according to the type of environment they occur in, and hence the level of estuarine dependence of the various species. Species belonging to each assemblage showed similarities with regards to their reproduction modes and/or preference to a particular physical condition. Some species were restricted to one environment, whilst others were common to two or all three environments. The occurrence of partially estuarine-dependent species in all three environments suggests that ocean-estuarine coupling is an important process for the recruitment success of these species. The ' best fitting ' physical variable

  11. Correlation between some selected trace metal concentrations in six species of fish from the Arabian Sea

    SciTech Connect

    Ashraf, M.; Jaffar, M.

    1988-07-01

    The role of trace metals in marine ecosystems has been keenly investigated during recent years. It is known that abundance of essential trace metals regulates the metal content in the organisms by homeostatic control mechanisms, which when cease to function cause essential trace metals to act in an either acutely or chronically toxic manner. Therefore, a correlation study based on essential and non-essential trace metal concentrations is imperative for extending the existing knowledge of bioaccumulation of trace metals in marine organisms. An attempt has been made in the present investigation to bring out quantitative correlations between the concentrations of iron, copper, lead and zinc in the edible muscle tissue of six species of marine fish: Salmon (salmon sole); tuna (thunnus thynnus); pomfret silver (pampus argenteus); Pomfret black (formioniger); long tail tuna (thynnus tonggel) and Indian oil sardine (sardinella longiceps). These fish are abundantly available in Pakistan along the coastal line of the Arabian Sea and have great commercial value. The computational analysis on the trace metal correlation was conducted using an MSTAT statistical package.

  12. Using species abundance distribution models and diversity indices for biogeographical analyses

    NASA Astrophysics Data System (ADS)

    Fattorini, Simone; Rigal, François; Cardoso, Pedro; Borges, Paulo A. V.

    2016-01-01

    We examine whether Species Abundance Distribution models (SADs) and diversity indices can describe how species colonization status influences species community assembly on oceanic islands. Our hypothesis is that, because of the lack of source-sink dynamics at the archipelago scale, Single Island Endemics (SIEs), i.e. endemic species restricted to only one island, should be represented by few rare species and consequently have abundance patterns that differ from those of more widespread species. To test our hypothesis, we used arthropod data from the Azorean archipelago (North Atlantic). We divided the species into three colonization categories: SIEs, archipelagic endemics (AZEs, present in at least two islands) and native non-endemics (NATs). For each category, we modelled rank-abundance plots using both the geometric series and the Gambin model, a measure of distributional amplitude. We also calculated Shannon entropy and Buzas and Gibson's evenness. We show that the slopes of the regression lines modelling SADs were significantly higher for SIEs, which indicates a relative predominance of a few highly abundant species and a lack of rare species, which also depresses diversity indices. This may be a consequence of two factors: (i) some forest specialist SIEs may be at advantage over other, less adapted species; (ii) the entire populations of SIEs are by definition concentrated on a single island, without possibility for inter-island source-sink dynamics; hence all populations must have a minimum number of individuals to survive natural, often unpredictable, fluctuations. These findings are supported by higher values of the α parameter of the Gambin mode for SIEs. In contrast, AZEs and NATs had lower regression slopes, lower α but higher diversity indices, resulting from their widespread distribution over several islands. We conclude that these differences in the SAD models and diversity indices demonstrate that the study of these metrics is useful for

  13. Habitat partitioning by five congeneric and abundant Choerodon species (Labridae) in a large subtropical marine embayment

    NASA Astrophysics Data System (ADS)

    Fairclough, D. V.; Clarke, K. R.; Valesini, F. J.; Potter, I. C.

    2008-04-01

    The habitats occupied by the juveniles and adults of five morphologically similar, diurnally active and abundant Choerodon species in the large subtropical environment of Shark Bay, a "World Heritage Property" on the west coast of Australia, have been determined. The densities of the two life cycle stages of each Choerodon species in those habitats were used in various analyses to test the hypotheses that: (1) habitats are partitioned among these species and between their juveniles and adults; (2) such habitat partitioning is greatest in the case of the two Western Australian endemic species, i.e. Choerodon rubescens and Choerodon cauteroma; and (3) the extent of habitat partitioning between both of these two species and the only species that is widely distributed in the Indo-West Pacific, i.e. Choerodon schoenleinii, will be less pronounced. Initially, catches of each of the five congeneric species, obtained during other studies in Shark Bay by angling, spearfishing and otter trawling, were collated to elucidate the broad distribution of these species in that embayment. Underwater visual census was then used to determine the densities of the juveniles and adults of each Choerodon species at sites representing the four habitat types in which one or more of these species had been caught, i.e. reefs in marine waters at the western boundary of the bay and seagrass, reefs and rocky shorelines in the two inner gulfs. The compositions of the Choerodon species over marine (entrance channel) reefs and in seagrass were significantly different and each differed significantly from those in both inner gulf reefs and rocky shorelines, which were, however, not significantly different. Choerodon rubescens was restricted to exposed marine reefs, and thus occupied a different habitat and location of the bay than C. cauteroma, the other endemic species, which was almost exclusively confined to habitats found in the inner gulfs. Choerodon cauteroma differed from other Choerodon

  14. Species composition and seasonal abundance of Chaetognatha in the subtropical coastal waters of Hong Kong

    NASA Astrophysics Data System (ADS)

    Tse, P.; Hui, S. Y.; Wong, C. K.

    2007-06-01

    Species composition, species diversity and seasonal abundance of chaetognaths were studied in Tolo Harbour and the coastal waters of eastern Hong Kong. Tolo Harbour is a semi-enclosed and poorly flushed bay with a long history of eutrophication. It opens into the eastern coast of Hong Kong which is fully exposed to water currents from the South China Sea. Zooplankton samples were collected monthly from July 2003 to July 2005 at six stations. Twenty species of chaetognaths were identified. They included six species of the genus Aidanosagitta ( Aidanosagitta neglecta, Aidanosagitta delicata, Aidanosagitta johorensis, Aidanosagitta regularis, Aidanosagitta bedfordii and Aidanosagitta crassa), four species of the genus Zonosagitta ( Zonosagitta nagae, Zonosagitta bedoti, Zonosagitta bruuni and Zonosagitta pulchra), three species of the genus Ferosagitta ( Ferosagitta ferox, Ferosagitta tokiokai and Ferosagitta robusta) and one species each from the genera Serratosagitta ( Serratosagitta pacifica), Decipisagitta ( Decipisagitta decipiens), Flaccisagitta ( Flaccisagitta enflata), Krohnitta ( Krohnitta pacifica), Mesosagitta ( Mesosagitta minima), Pterosagitta ( Pterosagitta draco) and Sagitta ( Sagitta bipunctata). The most abundant species were Flaccisagitta enflata, A. neglecta and A. delicata. Averaged over the entire study period, the densities of Flaccisagitta enflata, A. neglecta and A. delicata were 9.3, 6.6 and 5.2 ind. m -3, respectively. Overall, these species constituted 39.7%, 28.2% and 22.0% of all chaetognaths collected in the study. Averaged over the entire study, the density of most of the low abundance species was <0.6 ind. m -3. Flaccisagitta enflata occurred throughout the year at all sampling stations. Aidanosagitta neglecta occurred at all sampling stations, but was most common in summer. Aidanosagitta delicata was most common in Tolo Harbour during summer. Tolo Harbour supported larger populations, but fewer species of chaetognaths than the

  15. Tree species composition affects the abundance of rowan (Sorbus aucuparia L.) in urban forests in Finland.

    PubMed

    Hamberg, Leena; Lehvävirta, Susanna; Kotze, D Johan; Heikkinen, Juha

    2015-03-15

    Recent studies have shown a considerable increase in the abundance of rowan (Sorbus aucuparia) saplings in urban forests in Finland, yet the reasons for this increase are not well understood. Here we investigated whether canopy cover or tree species composition, i.e., the basal areas of different tree species in Norway spruce dominated urban forests, affects the abundances of rowan seedlings, saplings and trees. Altogether 24 urban forest patches were investigated. We sampled the number of rowan and other saplings, and calculated the basal areas of trees. We showed that rowan abundance was affected by tree species composition. The basal area of rowan trees (≥ 5 cm in diameter at breast height, dbh) decreased with increasing basal area of Norway spruce, while the cover of rowan seedlings increased with an increase in Norway spruce basal area. However, a decrease in the abundance of birch (Betula pendula) and an increase in the broad-leaved tree group (Acer platanoides, Alnus glutinosa, Alnus incana, Amelanchier spicata, Prunus padus, Quercus robur, Rhamnus frangula and Salix caprea) coincided with a decreasing number of rowans. Furthermore, rowan saplings were scarce in the vicinity of mature rowan trees. Although it seems that tree species composition has an effect on rowan, the relationship between rowan saplings and mature trees is complex, and therefore we conclude that regulating tree species composition is not an easy way to keep rowan thickets under control in urban forests in Finland. PMID:25588119

  16. Effects of urbanization on the distribution and abundance of amphibians and invasive species in southern California streams

    USGS Publications Warehouse

    Riley, S.P.D.; Busteed, G.T.; Kats, L.B.; Vandergon, T.L.; Lee, L.F.S.; Dagit, R.G.; Kerby, J.L.; Fisher, R.N.; Sauvajot, R.M.

    2005-01-01

    Urbanization negatively affects natural ecosystems in many ways, and aquatic systems in particular. Urbanization is also cited as one of the potential contributors to recent dramatic declines in amphibian populations. From 2000 to 2002 we determined the distribution and abundance of native amphibians and exotic predators and characterized stream habitat and invertebratecommunities in 35 streams in an urbanized landscape north of Los Angeles (U.S.A.). We measured watershed development as the percentage of area within each watershed occupied by urban land uses. Streams in more developed watersheds often had exotic crayfish (Procambarus clarkii) and fish, and had fewer native species such as California newts (Taricha torosa) and California treefrogs (Hyla cadaverina). These effects seemed particularly evident above 8% development, a result coincident with other urban stream studies that show negative impacts beginning at 10-15% urbanization. For Pacific treefrogs (H. regilla), the most widespread native amphibian, abundance was lower in the presence of exotic crayfish, although direct urbanization effects were not found. Benthic macroinvertebrate communities were also less diverse in urban streams, especially for sensitive species. Faunal community changes in urban streams may be related to changes in physical stream habitat, such as fewer pool and more run habitats and increased water depth and flow, leading to more permanent streams. Variation in stream permanence was particularly evident in 2002, a dry year when many natural streams were dry but urban streams were relatively unchanged. Urbanization has significantly altered stream habitat in this region and may enhance invasion by exotic species and negatively affect diversity and abundance of native amphibians. ??2005 Society for Conservation Biology.

  17. Distribution and abundance of larval fish in the nearshore waters of western Lake Huron

    USGS Publications Warehouse

    O'Gorman, Robert

    1983-01-01

    Ichthyoplankton was collected at 17 nearshore (bottom depth ≥5 m but ≤10 m) sites in western Lake Huron during 1973–75 with a 0.5-m net of 351-micron mesh towed at 99 m/min. Larvae of rainbow smelt (Osmerus mordax) dominated late spring and early summer catches and larvae of alewives (Alosa pseudoharengus) the midsummer catches. Larval yellow perch (Perca flavescens) were caught in early summer but were rarely the dominant species. The time of spawning and hatching, and thus occurrence of larvae, differed between areas but was less variable for alewives than for yellow perch. The appearance of larvae in Saginaw Bay was followed successively by their appearance in southern, central, and northern Lake Huron. Rainbow smelt were most abundant in northern Lake Huron and yellow perch and alewives in inner Saginaw Bay. Densities of either rainbow smelt or alewives occasionally exceeded 1/m3, whereas those of yellow perch never exceeded 0.1/m3. Abundance of alewives was usually highest 1 to 3 m beneath the surface and that of rainbow smelt 2 to at least 6 m beneath the surface. Important nursery areas of rainbow smelt were in bays and off irregular coastlines and those of yellow perch were in bays. All nearshore waters seemed equally important as nursery areas of alewives.

  18. 78 FR 60254 - Endangered and Threatened Species; Take of Anadromous Fish

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-01

    .... The first component involves a cage experiment in which post-emergent hatchery Chinook salmon would be... supplemented by dip netting three times before and after cage experiments to measure relative fish abundance...

  19. Fish is Fish: the use of experimental model species to reveal causes of skeletal diversity in evolution and disease

    PubMed Central

    Harris, M. P.; Henke, K.; Hawkins, M. B.; Witten, P. E.

    2014-01-01

    Summary Fishes are wonderfully diverse. This variety is a result of the ability of ray-finned fishes to adapt to a wide range of environments, and has made them more specious than the rest of vertebrates combined. With such diversity it is easy to dismiss comparisons between distantly related fishes in efforts to understand the biology of a particular fish species. However, shared ancestry and the conservation of developmental mechanisms, morphological features and physiology provide the ability to use comparative analyses between different organisms to understand mechanisms of development and physiology. The use of species that are amenable to experimental investigation provides tools to approach questions that would not be feasible in other ‘non-model’ organisms. For example, the use of small teleost fishes such as zebrafish and medaka has been powerful for analysis of gene function and mechanisms of disease in humans, including skeletal diseases. However, use of these fish to aid in understanding variation and disease in other fishes has been largely unexplored. This is especially evident in aquaculture research. Here we highlight the utility of these small laboratory fishes to study genetic and developmental factors that underlie skeletal malformations that occur under farming conditions. We highlight several areas in which model species can serve as a resource for identifying the causes of variation in economically important fish species as well as to assess strategies to alleviate the expression of the variant phenotypes in farmed fish. We focus on genetic causes of skeletal deformities in the zebrafish and medaka that closely resemble phenotypes observed both in farmed as well as natural populations of fishes. PMID:25221374

  20. The Distribution and Abundance of Bird Species: Towards a Satellite, Data Driven Avian Energetics and Species Richness Model

    NASA Technical Reports Server (NTRS)

    Smith, James A.

    2003-01-01

    This paper addresses the fundamental question of why birds occur where and when they do, i.e., what are the causative factors that determine the spatio-temporal distributions, abundance, or richness of bird species? In this paper we outline the first steps toward building a satellite, data-driven model of avian energetics and species richness based on individual bird physiology, morphology, and interaction with the spatio-temporal habitat. To evaluate our model, we will use the North American Breeding Bird Survey and Christmas Bird Count data for species richness, wintering and breeding range. Long term and current satellite data series include AVHRR, Landsat, and MODIS.

  1. Species abundance distribution and population dynamics in a two-community model of neutral ecology

    NASA Astrophysics Data System (ADS)

    Vallade, M.; Houchmandzadeh, B.

    2006-11-01

    Explicit formulas for the steady-state distribution of species in two interconnected communities of arbitrary sizes are derived in the framework of Hubbell’s neutral model of biodiversity. Migrations of seeds from both communities as well as mutations in both of them are taken into account. These results generalize those previously obtained for the “island-continent” model and they allow an analysis of the influence of the ratio of the sizes of the two communities on the dominance/diversity equilibrium. Exact expressions for species abundance distributions are deduced from a master equation for the joint probability distribution of species in the two communities. Moreover, an approximate self-consistent solution is derived. It corresponds to a generalization of previous results and it proves to be accurate over a broad range of parameters. The dynamical correlations between the abundances of a species in both communities are also discussed.

  2. Does beach nourishment have long-term effects on intertidal macroinvertebrate species abundance?

    NASA Astrophysics Data System (ADS)

    Leewis, Lies; van Bodegom, Peter M.; Rozema, Jelte; Janssen, Gerard M.

    2012-11-01

    Coastal squeeze is the largest threat for sandy coastal areas. To mitigate seaward threats, erosion and sea level rise, sand nourishment is commonly applied. However, its long-term consequences for macroinvertebrate fauna, critical to most ecosystem services of sandy coasts, are still unknown. Seventeen sandy beaches - nourished and controls - were sampled along a chronosequence to investigate the abundance of four dominant macrofauna species and their relations with nourishment year and relevant coastal environmental variables. Dean's parameter and latitude significantly explained the abundance of the spionid polychaete Scolelepis squamata, Beach Index (BI), sand skewness, beach slope and latitude explained the abundance of the amphipod Haustorius arenarius and Relative Tide Range (RTR), recreation and sand sorting explained the abundance of Bathyporeia sarsi. For Eurydice pulchra, no environmental variable explained its abundance. For H. arenarius, E. pulchra and B. sarsi, there was no relation with nourishment year, indicating that recovery took place within a year after nourishment. Scolelepis squamata initially profited from the nourishment with "over-recolonisation". This confirms its role as an opportunistic species, thereby altering the initial community structure on a beach after nourishment. We conclude that the responses of the four dominant invertebrates studied in the years following beach nourishment are species specific. This shows the importance of knowing the autecology of the sandy beach macroinvertebrate fauna in order to be able to mitigate the effects of beach nourishment and other environmental impacts.

  3. 9 CFR 83.3 - Interstate movement of live VHS-regulated fish species from VHS-regulated areas.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...-regulated fish species from VHS-regulated areas. 83.3 Section 83.3 Animals and Animal Products ANIMAL AND...-regulated fish species from VHS-regulated areas. (a) Except as provided in paragraphs (b) through (e) of this section, live VHS-regulated fish, including fish moved to live fish markets, may only be...

  4. 78 FR 18273 - Draft Guidance for Industry on Purchasing Reef Fish Species Associated With the Hazard of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-26

    ... Reef Fish Species Associated With the Hazard of Ciguatera Fish Poisoning; Availability AGENCY: Food and...: Purchasing Reef Fish Species Associated With the Hazard of Ciguatera Fish Poisoning.'' The draft guidance, when finalized, will advise primary seafood processors who purchase reef fish how to minimize the...

  5. 9 CFR 83.3 - Interstate movement of live VHS-regulated fish species from VHS-regulated areas.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...-regulated fish species from VHS-regulated areas. 83.3 Section 83.3 Animals and Animal Products ANIMAL AND...-regulated fish species from VHS-regulated areas. (a) Except as provided in paragraphs (b) through (e) of this section, live VHS-regulated fish, including fish moved to live fish markets, may only be...

  6. 9 CFR 83.3 - Interstate movement of live VHS-regulated fish species from VHS-regulated areas.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...-regulated fish species from VHS-regulated areas. 83.3 Section 83.3 Animals and Animal Products ANIMAL AND...-regulated fish species from VHS-regulated areas. (a) Except as provided in paragraphs (b) through (e) of this section, live VHS-regulated fish, including fish moved to live fish markets, may only be...

  7. 9 CFR 83.3 - Interstate movement of live VHS-regulated fish species from VHS-regulated areas.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...-regulated fish species from VHS-regulated areas. 83.3 Section 83.3 Animals and Animal Products ANIMAL AND...-regulated fish species from VHS-regulated areas. (a) Except as provided in paragraphs (b) through (e) of this section, live VHS-regulated fish, including fish moved to live fish markets, may only be...

  8. 9 CFR 83.3 - Interstate movement of live VHS-regulated fish species from VHS-regulated areas.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...-regulated fish species from VHS-regulated areas. 83.3 Section 83.3 Animals and Animal Products ANIMAL AND...-regulated fish species from VHS-regulated areas. (a) Except as provided in paragraphs (b) through (e) of this section, live VHS-regulated fish, including fish moved to live fish markets, may only be...

  9. Plankton studies in San Francisco Bay; IV, Phytoplankton abundance and species composition, January 1980 - February 1981

    USGS Publications Warehouse

    Wong, R.L.; Cloern, J.E.

    1982-01-01

    Data are presented on the phytoplankton species composition and abundance in San Francisco Bay from January 1980 through February 1981. Phytoplankton were identified and enumerated in surface samples collected approximately every two weeks at selected stations in the main channel of the Bay, and at shoal stations in the central portion of South San Francisco Bay, San Pablo Bay, and Suisun Bay. Also reported are separate species lists for microphytoplankton (< 60 micrometers) and macrophytoplankton (> 60 micrometers). (Author 's abstract)

  10. Individualistic sensitivities and exposure to climate change explain variation in species' distribution and abundance changes.

    PubMed

    Palmer, Georgina; Hill, Jane K; Brereton, Tom M; Brooks, David R; Chapman, Jason W; Fox, Richard; Oliver, Tom H; Thomas, Chris D

    2015-10-01

    The responses of animals and plants to recent climate change vary greatly from species to species, but attempts to understand this variation have met with limited success. This has led to concerns that predictions of responses are inherently uncertain because of the complexity of interacting drivers and biotic interactions. However, we show for an exemplar group of 155 Lepidoptera species that about 60% of the variation among species in their abundance trends over the past four decades can be explained by species-specific exposure and sensitivity to climate change. Distribution changes were less well predicted, but nonetheless, up to 53% of the variation was explained. We found that species vary in their overall sensitivity to climate and respond to different components of the climate despite ostensibly experiencing the same climate changes. Hence, species have undergone different levels of population "forcing" (exposure), driving variation among species in their national-scale abundance and distribution trends. We conclude that variation in species' responses to recent climate change may be more predictable than previously recognized. PMID:26601276

  11. Estimating species - area relationships by modeling abundance and frequency subject to incomplete sampling.

    PubMed

    Yamaura, Yuichi; Connor, Edward F; Royle, J Andrew; Itoh, Katsuo; Sato, Kiyoshi; Taki, Hisatomo; Mishima, Yoshio

    2016-07-01

    Models and data used to describe species-area relationships confound sampling with ecological process as they fail to acknowledge that estimates of species richness arise due to sampling. This compromises our ability to make ecological inferences from and about species-area relationships. We develop and illustrate hierarchical community models of abundance and frequency to estimate species richness. The models we propose separate sampling from ecological processes by explicitly accounting for the fact that sampled patches are seldom completely covered by sampling plots and that individuals present in the sampling plots are imperfectly detected. We propose a multispecies abundance model in which community assembly is treated as the summation of an ensemble of species-level Poisson processes and estimate patch-level species richness as a derived parameter. We use sampling process models appropriate for specific survey methods. We propose a multispecies frequency model that treats the number of plots in which a species occurs as a binomial process. We illustrate these models using data collected in surveys of early-successional bird species and plants in young forest plantation patches. Results indicate that only mature forest plant species deviated from the constant density hypothesis, but the null model suggested that the deviations were too small to alter the form of species-area relationships. Nevertheless, results from simulations clearly show that the aggregate pattern of individual species density-area relationships and occurrence probability-area relationships can alter the form of species-area relationships. The plant community model estimated that only half of the species present in the regional species pool were encountered during the survey. The modeling framework we propose explicitly accounts for sampling processes so that ecological processes can be examined free of sampling artefacts. Our modeling approach is extensible and could be applied to a

  12. Habitat traits and species interactions differentially affect abundance and body size in pond-breeding amphibians.

    PubMed

    Ousterhout, Brittany H; Anderson, Thomas L; Drake, Dana L; Peterman, William E; Semlitsch, Raymond D

    2015-07-01

    In recent studies, habitat traits have emerged as stronger predictors of species occupancy, abundance, richness and diversity than competition. However, in many cases, it remains unclear whether habitat also mediates processes more subtle than competitive exclusion, such as growth, or whether intra- and interspecific interactions among individuals of different species may be better predictors of size. To test whether habitat traits are a stronger predictor of abundance and body size than intra- and interspecific interactions, we measured the density and body size of three species of larval salamanders in 192 ponds across a landscape. We found that the density of larvae was best predicted by models that included habitat features, while models incorporating interactions among individuals of different species best explained the body size of larvae. Additionally, we found a positive relationship between focal species density and congener density, while focal species body size was negatively related to congener density. We posit that salamander larvae may not experience competitive exclusion and thus reduced densities, but instead compensate for increased competition behaviourally (e.g. reduced foraging), resulting in decreased growth. The discrepancy between larval density and body size, a strong predictor of fitness in this system, also highlights a potential shortcoming in using density or abundance as a metric of habitat quality or population health. PMID:25643605

  13. Regular Patterns for Proteome-Wide Distribution of Protein Abundance across Species

    PubMed Central

    Jiang, Ying; Ying, Wantao; Wu, Songfeng; Zhu, Yunping; Liu, Siqi; Yang, Pengyuan; Qian, Xiaohong; He, Fuchu

    2012-01-01

    A proteome of the bio-entity, including cell, tissue, organ, and organism, consists of proteins of diverse abundance. The principle that determines the abundance of different proteins in a proteome is of fundamental significance for an understanding of the building blocks of the bio-entity. Here, we report three regular patterns in the proteome-wide distribution of protein abundance across species such as human, mouse, fly, worm, yeast, and bacteria: in most cases, protein abundance is positively correlated with the protein's origination time or sequence conservation during evolution; it is negatively correlated with the protein's domain number and positively correlated with domain coverage in protein structure, and the correlations became stronger during the course of evolution; protein abundance can be further stratified by the function of the protein, whereby proteins that act on material conversion and transportation (mass category) are more abundant than those that act on information modulation (information category). Thus, protein abundance is intrinsically related to the protein's inherent characters of evolution, structure, and function. PMID:22427835

  14. Observed and predicted effects of climate change on species abundance in protected areas

    NASA Astrophysics Data System (ADS)

    Johnston, Alison; Ausden, Malcolm; Dodd, Andrew M.; Bradbury, Richard B.; Chamberlain, Dan E.; Jiguet, Frédéric; Thomas, Chris D.; Cook, Aonghais S. C. P.; Newson, Stuart E.; Ockendon, Nancy; Rehfisch, Mark M.; Roos, Staffan; Thaxter, Chris B.; Brown, Andy; Crick, Humphrey Q. P.; Douse, Andrew; McCall, Rob A.; Pontier, Helen; Stroud, David A.; Cadiou, Bernard; Crowe, Olivia; Deceuninck, Bernard; Hornman, Menno; Pearce-Higgins, James W.

    2013-12-01

    The dynamic nature and diversity of species' responses to climate change poses significant difficulties for developing robust, long-term conservation strategies. One key question is whether existing protected area networks will remain effective in a changing climate. To test this, we developed statistical models that link climate to the abundance of internationally important bird populations in northwestern Europe. Spatial climate-abundance models were able to predict 56% of the variation in recent 30-year population trends. Using these models, future climate change resulting in 4.0°C global warming was projected to cause declines of at least 25% for more than half of the internationally important populations considered. Nonetheless, most EU Special Protection Areas in the UK were projected to retain species in sufficient abundances to maintain their legal status, and generally sites that are important now were projected to be important in the future. The biological and legal resilience of this network of protected areas is derived from the capacity for turnover in the important species at each site as species' distributions and abundances alter in response to climate. Current protected areas are therefore predicted to remain important for future conservation in a changing climate.

  15. Pyrosequencing as a tool for rapid fish species identification and commercial fraud detection.

    PubMed

    De Battisti, Cristian; Marciano, Sabrina; Magnabosco, Cristian; Busato, Sara; Arcangeli, Giuseppe; Cattoli, Giovanni

    2014-01-01

    The increased consumption of fish products, as well as the occurrence of exotic fish species in the Mediterranean Sea and in the fish market, has increased the risk of commercial fraud. Furthermore, the great amount of processed seafood products has greatly limited the application of classic identification systems. DNA-based identification allows a clear and unambiguous detection of polymorphisms between species, permitting differentiation and identification of both commercial fraud and introduction of species with potential toxic effects on humans. In this study, a novel DNA-based approach for differentiation of fish species based on pyrosequencing technology has been developed. Raw and processed fish products were tested, and up to 25 species of fish belonging to Clupeiformes and Pleuronectiformes groups were uniquely and rapidly identified. The proper identification based on short and unique genetic sequence signatures demonstrates that this approach is promising and cost-effective for large-scale surveys. PMID:24350776

  16. Consequences of organic farming and landscape heterogeneity for species richness and abundance of farmland birds.

    PubMed

    Smith, Henrik G; Dänhardt, Juliana; Lindström, Ake; Rundlöf, Maj

    2010-04-01

    It has been suggested that organic farming may benefit farmland biodiversity more in landscapes that have lost a significant part of its former landscape heterogeneity. We tested this hypothesis by comparing bird species richness and abundance during the breeding season in organic and conventional farms, matched to eliminate all differences not directly linked to the farming practice, situated in either homogeneous plains with only a little semi-natural habitat or in heterogeneous farmland landscapes with abundant field borders and semi-natural grasslands. The effect of farm management on species richness interacted with landscape structure, such that there was a positive relationship between organic farming and diversity only in homogeneous landscapes. This pattern was mainly dependent on the species richness of passerine birds, in particular those that were invertebrate feeders. Species richness of non-passerines was positively related to organic farming independent of the landscape context. Bird abundance was positively related to landscape heterogeneity but not to farm management. This was mainly because the abundance of passerines, particularly invertebrate feeders, was positively related to landscape heterogeneity. We suggest that invertebrate feeders particularly benefit from organic farming because of improved foraging conditions through increased invertebrate abundances in otherwise depauperate homogeneous landscapes. Although many seed-eaters also benefit from increased insect abundance, they may also utilize crop seed resources in homogeneous landscapes and conventional farms. The occurrence of an interactive effect of organic farming and landscape heterogeneity on bird diversity will have consequences for the optimal allocation of resources to restore the diversity of farmland birds. PMID:20213151

  17. Do predators control prey species abundance? An experimental test with brown treesnakes on Guam

    USGS Publications Warehouse

    Campbell, Earl W., III; Yackel Adams, Amy A.; Converse, Sarah J.; Fritts, Thomas H.; Rodda, Gordon H.

    2012-01-01

    The effect of predators on the abundance of prey species is a topic of ongoing debate in ecology; the effect of snake predators on their prey has been less debated, as there exists a general consensus that snakes do not negatively influence the abundance of their prey. However, this viewpoint has not been adequately tested. We quantified the effect of brown treesnake (Boiga irregularis) predation on the abundance and size of lizards on Guam by contrasting lizards in two 1-ha treatment plots of secondary forest from which snakes had been removed and excluded vs. two 1-ha control plots in which snakes were monitored but not removed or excluded. We removed resident snakes from the treatment plots with snake traps and hand capture, and snake immigration into these plots was precluded by electrified snake barriers. Lizards were sampled in all plots quarterly for a year following snake elimination in the treatment plots. Following the completion of this experiment, we used total removal sampling to census lizards on a 100-m2 subsample of each plot. Results of systematic lizard population monitoring before and after snake removal suggest that the abundance of the skink, Carlia ailanpalai, increased substantially and the abundance of two species of gekkonids, Lepidodactylus lugubris and Hemidactylus frenatus, also increased on snake-free plots. No treatment effect was observed for the skink Emoia caeruleocauda. Mean snout–vent length of all lizard species only increased following snake removal in the treatment plots. The general increase in prey density and mean size was unexpected in light of the literature consensus that snakes do not control the abundance of their prey species. Our findings show that, at least where alternate predators are lacking, snakes may indeed affect prey populations.

  18. Fish allergy in patients with parvalbumin-specific immunoglobulin E depends on parvalbumin content rather than molecular differences in the protein among fish species.

    PubMed

    Kobayashi, Ayako; Kobayashi, Yukihiro; Shiomi, Kazuo

    2016-10-01

    Allergenic characteristics of purified parvalbumins from different fish species have not been thoroughly investigated. We revealed that purified parvalbumins from nine different fish species have identical IgE-reactivities and high cross-reactivities. We also showed that fish allergenicity is associated with the parvalbumin content of the fish species, rather than species-specific differences in the molecular characteristics of the individual parvalbumin proteins. PMID:27251554

  19. Using GIS mapping of the extent of nearshore rocky reefs to estimate the abundance and reproductive output of important fishery species.

    PubMed

    Claisse, Jeremy T; Pondella, Daniel J; Williams, Jonathan P; Sadd, James

    2012-01-01

    Kelp Bass (Paralabrax clathratus) and California Sheephead (Semicossyphus pulcher) are economically and ecologically valuable rocky reef fishes in southern California, making them likely indicator species for evaluating resource management actions. Multiple spatial datasets, aerial and satellite photography, underwater observations and expert judgment were used to produce a comprehensive map of nearshore natural rocky reef habitat for the Santa Monica Bay region (California, USA). It was then used to examine the relative contribution of individual reefs to a regional estimate of abundance and reproductive potential of the focal species. For the reefs surveyed for fishes (i.e. 18 out of the 22 in the region, comprising 82% the natural rocky reef habitat <30 m depth, with a total area of 1850 ha), total abundance and annual egg production of California Sheephead were 451 thousand fish (95% CI: 369 to 533 thousand) and 203 billion eggs (95% CI: 135 to 272 billion). For Kelp Bass, estimates were 805 thousand fish (95% CI: 669 to 941 thousand) and 512 billion eggs (95% CI: 414 to 610 billion). Size structure and reef area were key factors in reef-specific contributions to the regional egg production. The size structures of both species illustrated impacts from fishing, and results demonstrate the potential that relatively small increases in the proportion of large females on larger reefs could have on regional egg production. For California Sheephead, a substantial proportion of the regional egg production estimate (>30%) was produced from a relatively small proportion of the regional reef area (c. 10%). Natural nearshore rocky reefs make up only 11% of the area in the newly designated MPAs in this region, but results provide some optimism that regional fisheries could benefit through an increase in overall reproductive output, if adequate increases in size structure of targeted species are realized. PMID:22272326

  20. Using GIS Mapping of the Extent of Nearshore Rocky Reefs to Estimate the Abundance and Reproductive Output of Important Fishery Species

    PubMed Central

    Claisse, Jeremy T.; Pondella, Daniel J.; Williams, Jonathan P.; Sadd, James

    2012-01-01

    Kelp Bass (Paralabrax clathratus) and California Sheephead (Semicossyphus pulcher) are economically and ecologically valuable rocky reef fishes in southern California, making them likely indicator species for evaluating resource management actions. Multiple spatial datasets, aerial and satellite photography, underwater observations and expert judgment were used to produce a comprehensive map of nearshore natural rocky reef habitat for the Santa Monica Bay region (California, USA). It was then used to examine the relative contribution of individual reefs to a regional estimate of abundance and reproductive potential of the focal species. For the reefs surveyed for fishes (i.e. 18 out of the 22 in the region, comprising 82% the natural rocky reef habitat <30 m depth, with a total area of 1850 ha), total abundance and annual egg production of California Sheephead were 451 thousand fish (95% CI: 369 to 533 thousand) and 203 billion eggs (95% CI: 135 to 272 billion). For Kelp Bass, estimates were 805 thousand fish (95% CI: 669 to 941thousand) and 512 billion eggs (95% CI: 414 to 610 billion). Size structure and reef area were key factors in reef-specific contributions to the regional egg production. The size structures of both species illustrated impacts from fishing, and results demonstrate the potential that relatively small increases in the proportion of large females on larger reefs could have on regional egg production. For California Sheephead, a substantial proportion of the regional egg production estimate (>30%) was produced from a relatively small proportion of the regional reef area (c. 10%). Natural nearshore rocky reefs make up only 11% of the area in the newly designated MPAs in this region, but results provide some optimism that regional fisheries could benefit through an increase in overall reproductive output, if adequate increases in size structure of targeted species are realized. PMID:22272326

  1. 77 FR 23463 - Endangered and Threatened Species; Take of Anadromous Fish

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-19

    ... Anadromous Fish AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... Endangered Species Act section 10(a)(1)(A) permit to US Fish and Wildlife Service to collect Central Valley spring-run Chinook salmon eggs and juveniles from the Feather River Fish Hatchery to place into the...

  2. 76 FR 78242 - Endangered and Threatened Species; Take of Anadromous Fish

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-16

    ... Anadromous Fish AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... with section 10(a)(1)(A) of the ESA (16 U.S.C. 1531 et. seq) and regulations governing listed fish and... allow them to take all fish species covered in this notice while conducting research at Crims Island...

  3. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Southwest)

    SciTech Connect

    Siegfried, C.A. )

    1989-12-01

    Species profiles are literature summaries of the taxonomy, morphology, range, life history, and environmental requirements of coastal aquatic species. They are prepared to assist in environmental impact assessments. Crangonid shrimp once were important in an export fishery but are now the basis of a bait fishery in San Francisco Bay. The shrimp are important components of the estuarine system, serving as an important food of almost all sport and commercial fishes of west coast estuaries. Spawning occurs in waters of >15 ppT salinity. Ovigerous females are found year-round; abundance peaks in spring and summer in embayments and in winter offshore. Eggs hatch directly into planktonic zoea which require 30--40 days to develop into postlarvae. Larvae prefer surface waters, while postlarvae prefer bottom waters. Larvae are exposed to predominantly seaward currents and postlarvae to landward moving bottom currents. Juvenile crangonids are generally found in brackish to nearly fresh water but move to more saline waters as they mature. Crangonids are opportunistic predators of epibenthic and benthic forms. Annual abundance of crangonids in San Francisco Bay has been linked to the volume of freshwater flow to the estuary. Maintaining adequate freshwater flows to the estuary to ensure successful recruitment is vital to maintaining populations of this important component of the estuarine system. 56 refs., 4 figs.

  4. Fish species and community distributions as proxies for seafloor habitat distributions: The Stellwagen Bank National Marine Sanctuary example (Northwest Atlantic, Gulf of Maine)

    USGS Publications Warehouse

    Auster, P.J.; Joy, K.; Valentine, P.C.

    2001-01-01

    Defining the habitats of fishes and associated fauna on outer continental shelves is problematic given the paucity of data on the actual types and distributions of seafloor habitats. However many regions have good data on the distributions of fishes from resource surveys or catch statistics because of the economic importance of the fisheries. Fish distribution data (species or communities) have been used as a proxy for the distribution of habitats to develop precautionary conservation strategies for habitat protection (e.g., marine protected areas, fishing gear restrictions). In this study we assessed the relationships between the distributions of fish communities and species derived from trawl survey data with the spatial distribution of sediment types determined by sampling and acoustic reflectance derived from multibeam sonar surveys in Stellwagen Bank National Marine Sanctuary. Fish communities were correlated with reflectance values but all communities did not occur in unique sediment types. This suggests that use of community distributions as proxies for habitats should include the caveat that a greater number of communities within an area could indicate a greater range of habitat types. Single species distributions showed relationships between abundance and reflectance values. Trawl catches with low abundances had wide variations in reflectance values while those with high abundances had narrower ranges indicating habitat affinities. Significant non-random frequency-dependent relationships were observed for 17 of 20 species although only 12 of 20 species had significant relationships based on rank correlation. These results suggest that species distributions based on trawl survey data can be used as proxies for the distribution of seafloor habitats. Species with known habitat associations can be used to infer habitat requirements of co-occurring species and can be used to identify a range of habitat types.

  5. Fish species and community distributions as proxies for sea-floor habitat distributions: the Stellwagen Bank National Marine Sanctuary example (northwest Atlantic, Gulf Of Maine)

    USGS Publications Warehouse

    Auster, Peter J.; Joy, Kevin; Valentine, Page C.

    2001-01-01

    Defining the habitats of fishes and associated fauna on outer continental shelves is problematic given the paucity of data on the actual types and distributions of seafloor habitats. However many regions have good data on the distributions of fishes from resource surveys or catch statistics because of the economic importance of the fisheries. Fish distribution data (species or communities) have been used as a proxy for the distribution of habitats to develop precautionary conservation strategies for habitat protection (e.g., marine protected areas, fishing gear restrictions). In this study we assessed the relationships between the distributions of fish communities and species derived from trawl survey data with the spatial distribution of sediment types determined by sampling and acoustic reflectance derived from multibeam sonar surveys in Stellwagen Bank National Marine Sanctuary. Fish communities were correlated with reflectance values but all communities did not occur in unique sediment types. This suggests that use of community distributions as proxies for habitats should include the caveat that a greater number of communities within an area could indicate a greater range of habitat types. Single species distributions showed relationships between abundance and reflectance values. Trawl catches with low abundances had wide variations in reflectance values while those with high abundances had narrower ranges indicating habitat affinities. Significant non-random frequency-dependent relationships were observed for 17 of 20 species although only 12 of 20 species had significant relationships based on rank correlation. These results suggest that species distributions based on trawl survey data can be used as proxies for the distribution of seafloor habitats. Species with known habitat associations can be used to infer habitat requirements of co-occurring species and can be used to identify a range of habitat types.

  6. Species richness and relative species abundance of Nymphalidae (Lepidoptera) in three forests with different perturbations in the North-Central Caribbean of Costa Rica.

    PubMed

    Stephen, Carolyn; Sánchez, Ragde

    2014-09-01

    Measurements of species richness and species abundance can have important implications for regulations and conservation. This study investigated species richness and abundance of butterflies in the family Nymphalidae at undisturbed, and disturbed habitats in Tirimbina Biological Reserve and Nogal Private Reserve, Sarapiquí, Costa Rica. Traps baited with rotten banana were placed in the canopy and the understory of three habitats: within mature forest, at a river/forest border, and at a banana plantation/forest border. In total, 71 species and 487 individuals were caught and identified during May and June 2011 and May 2013. Species richness and species abundance were found to increase significantly at perturbed habitats (p < 0.0001, p < 0.0001, respectively). The edge effect, in which species richness and abundance increase due to greater complementary resources from different habitats, could be one possible explanation for increased species richness and abundance. PMID:25412524

  7. Specific IgE to fish extracts does not predict allergy to specific species within an adult fish allergic population

    PubMed Central

    2014-01-01

    Background Fish is an important cause of food allergy. Studies on fish allergy are scarce and in most cases limited to serological evaluation. Our objective was to study patterns of self-reported allergy and tolerance to different commonly consumed fish species and its correlation to IgE sensitization to the same species. Methods Thirty-eight adult fish allergic patients completed a questionnaire regarding atopy, age of onset and symptoms to 13 commonly consumed fish species in the Netherlands (pangasius, cod, herring, eel, hake, pollock, mackerel, tilapia, salmon, sardine, tuna, plaice and swordfish). Specific IgE to these fish extracts were analyzed by ImmunoCAP. Results Median age of onset of fish allergy was 8.5 years. Severe reactions were reported by the majority of patients (n = 20 (53%) respiratory and of these 20 patients, 6 also had cardiovascular symptoms). After diagnosis, 66% of the patients had eliminated all fish from their diet. Allergy to all species ever tried was reported by 59%. In relation to species ever tried, cod (84%) and herring (79%) were the most frequently reported culprit species while hake (57%) and swordfish (55%) were the least frequent. A positive sIgE (value ≥ 0.35 kUA/L) to the culprit species ranged between 50% (swordfish) and 100% (hake). In tolerant patients, a negative sIgE (value < 0.35 kUA/L) ranged from 0% (hake, pollock and swordfish) to 75% (sardine). For cod, the agreement between sIgE test results and reported allergy or tolerance was 82% and 25%, respectively. Sensitization to cod parvalbumin (Gad c 1) was present in 77% of all patients. Conclusion Serological cross-reactivity between fish species is frequent, but in a significant proportion of patients, clinical relevance appears to be limited to only certain species. A well-taken history or food challenge is required for discrimination between allergy to the different fish species. PMID:25225608

  8. Abundance-based similarity indices and their estimation when there are unseen species in samples.

    PubMed

    Chao, Anne; Chazdon, Robin L; Colwell, Robert K; Shen, Tsung-Jen

    2006-06-01

    A wide variety of similarity indices for comparing two assemblages based on species incidence (i.e., presence/absence) data have been proposed in the literature. These indices are generally based on three simple incidence counts: the number of species shared by two assemblages and the number of species unique to each of them. We provide a new probabilistic derivation for any incidence-based index that is symmetric (i.e., the index is not affected by the identity ordering of the two assemblages) and homogeneous (i.e., the index is unchanged if all counts are multiplied by a constant). The probabilistic approach is further extended to formulate abundance-based indices. Thus any symmetric and homogeneous incidence index can be easily modified to an abundance-type version. Applying the Laplace approximation formulas, we propose estimators that adjust for the effect of unseen shared species on our abundance-based indices. Simulation results show that the adjusted estimators significantly reduce the biases of the corresponding unadjusted ones when a substantial fraction of species is missing from samples. Data on successional vegetation in six tropical forests are used for illustration. Advantages and disadvantages of some commonly applied indices are briefly discussed. PMID:16918900

  9. Myxidium leei (Myxozoa) infections in aquarium-reared Mediterranean fish species.

    PubMed

    Padrós, F; Palenzuela, O; Hispano, C; Tosas, O; Zarza, C; Crespo, S; Alvarez-Pellitero, P

    2001-10-29

    An episode of parasitic enteritis causing trickling mortalities at an exhibition aquarium reproducing Mediterranean ecosystems was found to be caused by the myxozoan parasite Myxidium leei Diamant, Lom & Dykova 1994. The myxozoan was recorded in 25 different fish species belonging to 16 Genera, 10 Families and 4 Orders. It was mainly detected in the intestine of affected fish, and was responsible for severe chronic enteritis. The parasite was probably introduced into the facilities with infected wild fish, and transmitted directly from fish to fish by cohabitation, transfer of infected material and necrophagia. Fish belonging to the Families Labridae and Blenniidae appeared as most susceptible, and the incidence of infections in members of the Sparidae was low. This study significantly widens the host spectrum for this virulent parasite and now includes many ubiquitous coastal Mediterranean species. Wild fish may have a significant role in the transmission of myxidiosis of cultured sparid fish. PMID:11797916

  10. Abundance of biting midge species (Diptera: Ceratopogonidae, Culicoides spp.) on cattle farms in Korea

    PubMed Central

    Oem, Jae-Ku; Chung, Joon-Yee; Kwon, Mee-Soon; Kim, Toh-Kyung; Lee, Tae-Uk

    2013-01-01

    Culicoides biting midges were collected on three cattle farms weekly using light traps overnight from May to October between 2010 and 2011 in the southern part of Korea. The seasonal and geographical abundance of Culicodes spp. were measured. A total of 16,538 biting midges were collected from 2010 to 2011, including seven species of Culicoides, four of which represented 98.42% of the collected specimens. These four species were Culicodes (C.) punctatus (n = 14,413), C. arakawae (n = 1,120), C. oxystoma (n = 427), and C. maculatus (n = 318). C. punctatus was the predominant species (87.15%). PMID:23388441

  11. Methanotrophic community abundance and composition in plateau soils with different plant species and plantation ways.

    PubMed

    Dai, Yu; Wu, Zhen; Xie, Shuguang; Liu, Yong

    2015-11-01

    Aerobic methane-oxidizing bacteria (MOB) play an important role in mitigating the methane emission in soil ecosystems to the atmosphere. However, the impact of plant species and plantation ways on the distribution of MOB remains unclear. The present study investigated MOB abundance and structure in plateau soils with different plant species and plantation ways (natural and managed). Soils were collected from unmanaged wild grassland and naturally forested sites, and managed farmland and afforested sites. A large variation in MOB abundance and structure was found in these studied soils. In addition, both type I MOB (Methylocaldum) and type II MOB (Methylocystis) were detected in these soils, while type II MOB usually outnumbered type I MOB. The distribution of soil MOB community was found to be collectively regulated by plantation way, plant species, the altitude of sampling site, and soil properties. PMID:26142389

  12. Historic Mining and Agriculture as Indicators of Occurrence and Abundance of Widespread Invasive Plant Species

    PubMed Central

    Calinger, Kellen; Calhoon, Elisabeth; Chang, Hsiao-chi; Whitacre, James; Wenzel, John; Comita, Liza; Queenborough, Simon

    2015-01-01

    Anthropogenic disturbances often change ecological communities and provide opportunities for non-native species invasion. Understanding the impacts of disturbances on species invasion is therefore crucial for invasive species management. We used generalized linear mixed effects models to explore the influence of land-use history and distance to roads on the occurrence and abundance of two invasive plant species (Rosa multiflora and Berberis thunbergii) in a 900-ha deciduous forest in the eastern U.S.A., the Powdermill Nature Reserve. Although much of the reserve has been continuously forested since at least 1939, aerial photos revealed a variety of land-uses since then including agriculture, mining, logging, and development. By 2008, both R. multiflora and B. thunbergii were widespread throughout the reserve (occurring in 24% and 13% of 4417 10-m diameter regularly-placed vegetation plots, respectively) with occurrence and abundance of each varying significantly with land-use history. Rosa multiflora was more likely to occur in historically farmed, mined, logged or developed plots than in plots that remained forested, (log odds of 1.8 to 3.0); Berberis thunbergii was more likely to occur in plots with agricultural, mining, or logging history than in plots without disturbance (log odds of 1.4 to 2.1). Mining, logging, and agriculture increased the probability that R. multiflora had >10% cover while only past agriculture was related to cover of B. thunbergii. Proximity to roads was positively correlated with the occurrence of R. multiflora (a 0.26 increase in the log odds for every 1-m closer) but not B. thunbergii, and roads had no impact on the abundance of either species. Our results indicated that a wide variety of disturbances may aid the introduction of invasive species into new habitats, while high-impact disturbances such as agriculture and mining increase the likelihood of high abundance post-introduction. PMID:26046534

  13. Historic Mining and Agriculture as Indicators of Occurrence and Abundance of Widespread Invasive Plant Species.

    PubMed

    Calinger, Kellen; Calhoon, Elisabeth; Chang, Hsiao-Chi; Whitacre, James; Wenzel, John; Comita, Liza; Queenborough, Simon

    2015-01-01

    Anthropogenic disturbances often change ecological communities and provide opportunities for non-native species invasion. Understanding the impacts of disturbances on species invasion is therefore crucial for invasive species management. We used generalized linear mixed effects models to explore the influence of land-use history and distance to roads on the occurrence and abundance of two invasive plant species (Rosa multiflora and Berberis thunbergii) in a 900-ha deciduous forest in the eastern U.S.A., the Powdermill Nature Reserve. Although much of the reserve has been continuously forested since at least 1939, aerial photos revealed a variety of land-uses since then including agriculture, mining, logging, and development. By 2008, both R. multiflora and B. thunbergii were widespread throughout the reserve (occurring in 24% and 13% of 4417 10-m diameter regularly-placed vegetation plots, respectively) with occurrence and abundance of each varying significantly with land-use history. Rosa multiflora was more likely to occur in historically farmed, mined, logged or developed plots than in plots that remained forested, (log odds of 1.8 to 3.0); Berberis thunbergii was more likely to occur in plots with agricultural, mining, or logging history than in plots without disturbance (log odds of 1.4 to 2.1). Mining, logging, and agriculture increased the probability that R. multiflora had >10% cover while only past agriculture was related to cover of B. thunbergii. Proximity to roads was positively correlated with the occurrence of R. multiflora (a 0.26 increase in the log odds for every 1-m closer) but not B. thunbergii, and roads had no impact on the abundance of either species. Our results indicated that a wide variety of disturbances may aid the introduction of invasive species into new habitats, while high-impact disturbances such as agriculture and mining increase the likelihood of high abundance post-introduction. PMID:26046534

  14. Annual cycle of zooplankton abundance and species composition in Izmit Bay (the northeastern Marmara Sea)

    NASA Astrophysics Data System (ADS)

    Isinibilir, Melek; Kideys, Ahmet E.; Tarkan, Ahmet N.; Yilmaz, I. Noyan

    2008-07-01

    The monthly abundance, biomass and taxonomic composition of zooplankton of Izmit Bay (the northeastern Marmara Sea) were studied from October 2001 to September 2002. Most species within the zooplankton community displayed a clear pattern of succession throughout the year. Generally copepods and cladocerans were the most abundant groups, while the contribution of meroplankton increased at inner-most stations and dominated the zooplankton. Both species number ( S) and diversity ( H') were positively influenced by the increase in salinity of upper layers ( r = 0.30 and r = 0.31, p < 0.001, respectively), while chlorophyll a was negatively affected ( r = -0.36, p < 0.001). Even though Noctiluca scintillans had a significant seasonality ( F11,120 = 8.45, p < 0.001, ANOVA), abundance was not related to fluctuations in temperature and only chlorophyll a was adversely correlated ( r = -0.35, p < 0.001). In general, there are some minor differences in zooplankton assemblages of upper and lower layers. A comparison of the species composition and abundance of Izmit Bay with other Black Sea bays reveals a high similarity between them.

  15. Species List of Alaskan Birds, Mammals, Fish, Amphibians, Reptiles, and Invertebrates. Alaska Region Report Number 82.

    ERIC Educational Resources Information Center

    Taylor, Tamra Faris

    This publication contains a detailed list of the birds, mammals, fish, amphibians, reptiles, and invertebrates found in Alaska. Part I lists the species by geographical regions. Part II lists the species by the ecological regions of the state. (CO)

  16. SURROGATE SPECIES IN ASSESSING CONTAMINANT RISK FOR ENDANGERED FISHES, INCLUDING INTERSPECIES TOXICITY CORRELATIONS

    EPA Science Inventory

    Rainbow trout, fathead minnows, and sheepshead minnows were tested as surrogate species to assess contaminant risk for 17 endangered fishes and one toad species. Acute toxicity tests were conducted with carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin in accorda...

  17. LOCATIONAL DIFFERENCES IN MERCURY AND SELENIUM LEVELS IN 19 SPECIES OF SALTWATER FISH FROM NEW JERSEY

    PubMed Central

    Burger, Joanna; Jeitner, Christian; Gochfeld, Michael

    2014-01-01

    Individuals who fish, and their families that ingest self-caught fish, make decisions about where to fish, what type of fish to eat, and the quantity of fish to eat. While federal and state agencies often issue consumption advisories for some fish with high mercury (Hg) concentrations, advisories seldom provide the actual metal levels to the general public. There are few data for most saltwater fish, and even less information on variations in Hg levels in fish within a state or geographical region. The objective of this study was to provide Hg concentrations from 19 species of fish caught in different locations in New Jersey to (1) test the hypothesis that mean metal levels vary geographically, (2) provide this information to individuals who fish these coastal waters, and (3) provide a range of values for risk assessors who deal with saltwater fish exposure in the Northeastern United States. Selenium (Se) was also examined because of its purported moderating effect on the toxicity of Hg. Hg levels showed significant geographical variation for 10 of 14 species that were caught in more than one region of New Jersey, but there were significant locational differences for Se in only 5 of the fish. Mercury levels were significantly lower in fish collected from northern New Jersey (except for ling, Molva molva), compared to other regions. As might be expected, locational differences in Hg levels were greatest for fish species with the highest Hg concentrations (shark, Isurus oxyrinchus; tuna, Thunnus thynnus and T. albacares; striped bass, Morone saxatilis; bluefish, Pomatomus saltatrix). Fishers and their families might reduce their risk from Hg exposure not only by selecting fish generally lower in Hg, but by fishing predominantly in some regions over others, further lowering the potential risk. Health professionals might use these data to advise patients on which fish are safest to consume (in terms of Hg exposure) from particular geographical regions. PMID:21598171

  18. Locational differences in mercury and selenium levels in 19 species of saltwater fish from New Jersey.

    PubMed

    Burger, Joanna; Jeitner, Christian; Gochfeld, Michael

    2011-01-01

    Individuals who fish, and their families that ingest self-caught fish, make decisions about where to fish, what type of fish to eat, and the quantity of fish to eat. While federal and state agencies often issue consumption advisories for some fish with high mercury (Hg) concentrations, advisories seldom provide the actual metal levels to the general public. There are few data for most saltwater fish, and even less information on variations in Hg levels in fish within a state or geographical region. The objective of this study was to provide Hg concentrations from 19 species of fish caught in different locations in New Jersey to (1) test the hypothesis that mean metal levels vary geographically, (2) provide this information to individuals who fish these coastal waters, and (3) provide a range of values for risk assessors who deal with saltwater fish exposure in the Northeastern United States. Selenium (Se) was also examined because of its purported moderating effect on the toxicity of Hg. Hg levels showed significant geographical variation for 10 of 14 species that were caught in more than one region of New Jersey, but there were significant locational differences for Se in only 5 of the fish. Mercury levels were significantly lower in fish collected from northern New Jersey (except for ling, Molva molva), compared to other regions. As might be expected, locational differences in Hg levels were greatest for fish species with the highest Hg concentrations (shark, Isurus oxyrinchus; tuna, Thunnus thynnus and T. albacares; striped bass, Morone saxatilis; bluefish, Pomatomus saltatrix). Fishers and their families might reduce their risk from Hg exposure not only by selecting fish generally lower in Hg, but by fishing predominantly in some regions over others, further lowering the potential risk. Health professionals might use these data to advise patients on which fish are safest to consume (in terms of Hg exposure) from particular geographical regions. PMID:21598171

  19. The fish species composition and variation of catch from the small-scale gillnet fishery before, during and after the 1997-1998 ENSO event, central Mexican Pacific.

    PubMed

    Rojo-Vázquez, J A; Quiñonez-Velázquez, C; Echavarria-Heras, H A; Lucano-Ramirez, G; Godínez-Domínguez, E; Ruiz-Ramírez, S; Galván-Piña, V H; Sosa-Nishizaki, O

    2008-03-01

    In the tropical and subtropical coastal zone, were highly diverse fish communities occur, it is important to study the small scale fisheries exploiting these communities. For this study, 219 fishing days were carried out in Bahia de Navidad, Jalisco, Mexico. Four gillnets with different mesh sizes (76.2, 88.9, 101.6 and 114.3 mm) were used for the fishing operations, from April 1994 to March 1995 and from January 1998 to December 2000. A total of 26126 organisms weighting 11680 kg were caught. One hundred and eighty three species belonging to 57 families and 19 orders were identified. Ten species accumulated more than 60% of the total abundance and biomass, the remaining species (173) individually contributed with less than 2% of the total abundance and biomass. The most important species in the catch were Microlepidotus brevipinnis, Caranx caballus, Haemulon flaviguttatum, Scomberomorus sierra, C. caninus, C. sexfjasciatus, Lutjanus guttatus and L. argentiventris. The catch per unit of effort showed a large variation during the study, both in number and biomass. On average, 110 fishes and 48.5 kg fishing day(-1) were caught. The maximum values were recorded during January and October 1998 (250 fishes and 100 kg fishing day(-1)), and the minimum values were recorded during September and November 1994 (25 org. and 10 kg fishing day(-1)). The total abundance and biomass was lower during the 1994-95 period (F=6.16, 8.32, P<0.05). There were statistically significant differences among the annual catch from each gillnet. All the environmental changes caused by the ENSO event had ecological and economic effects that can be rated from moderate to severe. PMID:18624232

  20. Quantification of major allergen parvalbumin in 22 species of fish by SDS-PAGE.

    PubMed

    Kobayashi, Yukihiro; Yang, Tao; Yu, Cheng-Tao; Ume, Chiaki; Kubota, Hiroyuki; Shimakura, Kuniyoshi; Shiomi, Kazuo; Hamada-Sato, Naoko

    2016-03-01

    Fish is an important causative material of food allergy. Although the allergenicity of fish is considered to correlate with the content of parvalbumin, the major fish allergen, available information about the parvalbumin content in fish is limited. In this study, a simple and reliable quantification method for fish parvalbumin by SDS-PAGE was first established. Application of the SDS-PAGE method to 22 species of fish revealed a marked variation in parvalbumin content among fish. Furthermore, the parvalbumin content was found to be higher in dorsal white muscle than in ventral white muscle, in rostral part of white muscle than in caudal part of white muscle and in white muscle than in dark muscle. IgE reactivity of fish was roughly proportional to parvalbumin content. Interestingly, large-sized migratory fish, such as salmon, swordfish and tuna, were commonly very low in both parvalbumin content and IgE reactivity. PMID:26471564

  1. Species Abundance Distribution of Ectoparasites on Norway Rats (Rattus norvegicus) from a Localized Area in Southwest China

    PubMed Central

    Guo, Xian Guo; Dong, Wen Ge; Men, Xing Yuan; Qian, Ti Jun; Wu, Dian; Ren, Tian Guang; Qin, Feng; Song, Wen Yu; Yang, Zhi Hua; Fletcher, Quinn E

    2016-01-01

    Background: The species of ectoparasites that live on a specific host in a geographical region form an ectoparasite community. Species abundance distributions describe the number of individuals observed for each different species that is encountered within a community. Based on properties of the species abundance distribution, the expected total number of species present in the community can be estimated. Methods: Preston’s lognormal distribution model was used to fit the expected species abundance distribution curve. Using the expected species abundance distribution curve, we estimated the total number of expected parasite species present and the amount of species that were likely missed by our sampling in the field. Results: In total, 8040 ectoparasites (fleas, sucking lice, gamasid mites and chigger mites) were collected from 431 Norway rats (Rattus norvegicus) from a localized area in southwest China. These ectoparasites were identified to be 47 species from 26 genera in 10 families. The majority of ectoparasite species were chigger mites (family Trombiculidae) while the majority of individuals were sucking lice in the family Polyplacidae. The expected species abundance distribution curve demonstrated the classic pattern that the majority of ectoparasite species were rare and that there were a few common species. The total expected number of ectoparasite species on R. norvegicus was estimated to be 85 species, and 38 species were likely missed by our sampling in the field. Conclusions: Norway rats harbor a large suite of ectoparasites. Future field investigations should sample large numbers of host individuals to assess ectoparasite populations. PMID:27308277

  2. Including independent estimates and uncertainty to quantify total abundance of fish migrating in a large river system: walleye (Sander vitreus) in the Maumee River, Ohio

    USGS Publications Warehouse

    Pritt, Jeremy J.; DuFour, Mark R.; Mayer, Christine M.; Kocovsky, Patrick M.; Tyson, Jeffrey T.; Weimer, Eric J.; Vandergoot, Christopher S.

    2013-01-01

    Walleye (Sander vitreus) in Lake Erie is a valuable and migratory species that spawns in tributaries. We used hydroacoustic sampling, gill net sampling, and Bayesian state-space modeling to estimate the spawning stock abundance, characterize size and sex structure, and explore environmental factors cuing migration of walleye in the Maumee River for 2011 and 2012. We estimated the spawning stock abundance to be between 431,000 and 1,446,000 individuals in 2011 and between 386,400 and 857,200 individuals in 2012 (95% Bayesian credible intervals). A back-calculation from a concurrent larval fish study produced an estimate of 78,000 to 237,000 spawners for 2011. The sex ratio was skewed towards males early in the spawning season but approached 1:1 later, and larger individuals entered the river earlier in the season than smaller individuals. Walleye migration was greater during low river discharge and intermediate temperatures. Our approach to estimating absolute abundance and uncertainty as well as characterization of the spawning stock could improve assessment and management of this species, and our methodology is applicable to other diadromous populations.

  3. Rich and rare—First insights into species diversity and abundance of Antarctic abyssal Gastropoda (Mollusca)

    NASA Astrophysics Data System (ADS)

    Schwabe, Enrico; Michael Bohn, Jens; Engl, Winfried; Linse, Katrin; Schrödl, Michael

    2007-08-01

    , and all these 84 species seem endemic to Antarctica south of the Polar Front. Comparing diversity and abundances based on epibenthic sledge samples, there is no clear relationship between Antarctic deep-sea gastropod abundance and species richness with depth. However, both Antarctic and adjacent deep-sea areas are still far from being adequately sampled to allow more comprehensive conclusions.

  4. Diet of juvenile lake trout in southern Lake Ontario in relation to abundance and size of prey fishes, 1979-1987

    USGS Publications Warehouse

    Elrod, Joseph H.; O'Gorman, Robert

    1991-01-01

    We examined the diet of juvenile lake trout Salvelinus namaycush (<450 mm, total length) in Lake Ontario during four sampling periods (April–May, June, July–August, and October 1979–1987) in relation to changes in prey fish abundance in the depth zone where we caught the lake trout. Over all years combined, slimy sculpins Cottus cognatus contributed the most (39–52%) by wet weight to the diet, followed by alewives Alosa pseudoharengus(3–38%), rainbow smelt Osmerus mordax (17–43%), and johnny darters Etheostoma nigrum(2–10%). Over 90% of alewives eaten during April–May and June were age 1, and 98% of those eaten during October were age 0 (few alewives were eaten in July–August). Mean lengths of rainbow smelt and slimy sculpins in stomachs increased with size of lake trout. Juvenile lake trout generally fed opportunistically—seasonal and annual changes in diet usually reflected seasonal and annual changes in abundance of prey fishes near bottom where we captured the lake trout. Furthermore, diet within a given season varied with depth of capture of lake trout, and changes with depth in proportions of prey species in lake trout stomachs mirrored changes in proportions of the prey species in trawl catches at the same depth. Alewives (ages 0 and 1) were the only prey fish eaten in substantial quantities by both juvenile lake trout and other salmonines, and thus are a potential focus of competition between these predators.

  5. Effect of trophic status in lakes on fungal species diversity and abundance.

    PubMed

    Pietryczuk, A; Cudowski, A; Hauschild, T

    2014-11-01

    The objective of this study was to determine the species diversity and abundance of fungi in relation to the hydrochemical conditions, with special emphasis on the trophic status and degree of pollution of lakes. The study was conducted in 14 lakes of the Augustów Lakeland (central Europe, NE Poland) with different hydrological conditions, type of stratification and trophic status. The analyses were performed in the hydrological year 2013. In the waters of the studied lakes, the mean abundance of fungi was 5600±3600 CFU/mL. The minimum value (800 CFU/mL) was recorded for the mesotrophic Płaskie Lake, and the maximum value (14,000 CFU/mL) was recorded for the eutrophic Pobojno Lake. A total of 38 species of fungi were identified, including 11 belonging to the aquatic hyphomycetes; up to 14 species were potentially pathogenic fungi. The potentially pathogenic fungi, particularly Candida albicans and Scopulariopsis fusca, were found in lakes with increased concentrations of chloride and sulphate(VI) ions and may thus serve as indicators of the degree of water pollution. This paper illustrates that the species diversity and abundance of fungi in limnic waters depend on the concentration of organic matter, chlorophyll a concentration, and the degree of water pollution. The results suggest that aquatic fungi can be a valuable indicator of the degree of pollution and the sanitary quality of the water. PMID:25145569

  6. Niche and neutral models predict asymptotically equivalent species abundance distributions in high-diversity ecological communities

    PubMed Central

    Chisholm, Ryan A.; Pacala, Stephen W.

    2010-01-01

    A fundamental challenge in ecology is to understand the mechanisms that govern patterns of relative species abundance. Previous numerical simulations have suggested that complex niche-structured models produce species abundance distributions (SADs) that are qualitatively similar to those of very simple neutral models that ignore differences between species. However, in the absence of an analytical treatment of niche models, one cannot tell whether the two classes of model produce the same patterns via similar or different mechanisms. We present an analytical proof that, in the limit as diversity becomes large, a strong niche model give rises to exactly the same asymptotic form of SAD as the neutral model, and we verify the analytical predictions for a Panamanian tropical forest data set. Our results strongly suggest that neutral processes drive patterns of relative species abundance in high-diversity ecological communities, even when strong niche structure exists. However, neutral theory cannot explain what generates high diversity in the first place, and it may not be valid in low-diversity communities. Our results also confirm that neutral theory cannot be used to infer an absence of niche structure or to explain ecosystem function. PMID:20733073

  7. Culicoides monitoring in Belgium in 2011: analysis of spatiotemporal abundance, species diversity and Schmallenberg virus detection.

    PubMed

    DE Regge, N; DE Deken, R; Fassotte, C; Losson, B; Deblauwe, I; Madder, M; Vantieghem, P; Tomme, M; Smeets, F; Cay, A B

    2015-09-01

    In 2011, Culicoides (Diptera: Ceratopogonidae) were collected at 16 locations covering four regions of Belgium with Onderstepoort Veterinary Institute (OVI) traps and at two locations with Rothamsted suction traps (RSTs). Quantification of the collections and morphological identification showed important variations in abundance and species diversity between individual collection sites, even for sites located in the same region. However, consistently higher numbers of Culicoides midges were collected at some sites compared with others. When species abundance and diversity were analysed at regional level, between-site variation disappeared. Overall, species belonging to the subgenus Avaritia together with Culicoides pulicaris (subgenus Culicoides) were the most abundant, accounting for 80% and 96% of all midges collected with RSTs and OVI traps, respectively. Culicoides were present during most of the year, with Culicoides obsoletus complex midges found from 9 February until 27 December. Real-time reverse-transcription polymerase chain reaction screening for Schmallenberg virus in the heads of collected midges resulted in the first detection of the virus in August 2011 and identified C. obsoletus complex, Culicoides chiopterus and Culicoides dewulfi midges as putative vector species. At Libramont in the south of Belgium, no positive pools were identified. PMID:25761054

  8. [Preparation and analysis of dehydrated mixtures of vegetables and underutilized fish species flours: I. Dehydrated mixtures of cereal-fish].

    PubMed

    Luna, G; Rey, J L; Castro, L M; Corona, N; Ferreiros, E; Luzardo, M

    1990-09-01

    For the purpose of providing possible solutions to the malnutrition problems affecting those populations where cereals and tubers form an important portion of their daily intake, products were prepared from dehydrated mixtures of cereals and under-utilized fish, but which contain high-quality protein. Two cereals were selected for our experiments: rice and corn, and a marine under-utilized fish species (Macrodon ancyclodon). The minced fish muscle recovered by mechanical deboning was mixed with the cereal, obtaining mixtures with 5%, 10% and 15% fish on a dry basis. Feeding experiments using Wistar weaning rats were then carried out to evaluate the most important characteristics. An amino acid profile which reflected high-quality protein was obtained, as evidenced by the excellent PER, NPU, NPR and digestibility values determined. The dehydrated mixtures of fish/cereal flour prepared with 5% and up to 10% fish (dry basis), did not present any odour, but as of the 15% level, fish odour was perceived. Therefore, the use of dehydrated mixtures of fish/cereal flours with up to 10% fish in preparing food products, is recommended, since these would be of great help in solving the scarcity of good-quality protein, particularly in the developing countries. PMID:2134143

  9. Differential effects of cocaine exposure on the abundance of phospholipid species in rat brain and blood*

    PubMed Central

    Cummings, Brian S.; Pati, Sumitra; Sahin, Serap; Scholpa, Natalie E.; Monian, Prashant; Trinquero, Paul O.; Clark, Jason K.; Wagner, John J.

    2015-01-01

    Background Lipid profiles in the blood are altered in human cocaine users, suggesting that cocaine-exposure can induce lipid remodeling. Methods Cocaine-induced locomotor sensitization in rats was followed by shotgun lipidomics using electrospray ionization-mass spectrometry (ESI-MS) and determined changes in brain tissues. To determine if any lipidomic changes were also reflected in the blood, we performed principal component analysis (PCA) of lipidomic spectra isolated from cocaine-treated animals. Alterations in the abundance of phospholipid species were correlated with behavioral changes in the magnitude of either the initial response to drug or locomotor sensitization. Results Behavioral sensitization altered the relative abundance of several phospholipid species in the hippocampus and cerebellum, measured one week following the final exposure to cocaine. In contrast, relatively few effects on phospholipids in either the dorsal or the ventral striatum were observed. PCA analysis demonstrated that cocaine altered the relative abundance of several glycerophospholipid species as compared to saline-injected controls. Subsequent MS/MS analysis identified some of these lipids as phosphatidylethanolamines, phosphatidylserines and phosphatidylcholines. The relative abundance of some of these phospholipid species were well correlated (R2 of 0.7 or higher) with either the initial response to cocaine or locomotor sensitization. Conclusion Taken together, these data demonstrate that a cocaine-conditioning experience results in the remodeling of specific phospholipids in rat brain tissue in a region-specific manner and also alters the intensities and types of phospholipid species in rat blood. These results further suggest that such changes may serve as biomarkers to assess the neuroadaptations occurring following repeated exposure to cocaine. PMID:25960140

  10. Estimating species – area relationships by modeling abundance and frequency subject to incomplete sampling

    USGS Publications Warehouse

    Yamaura, Yuichi; Connor, Edward F.; Royle, Andy; Itoh, Katsuo; Sato, Kiyoshi; Taki, Hisatomo; Mishima, Yoshio

    2016-01-01

    Models and data used to describe species–area relationships confound sampling with ecological process as they fail to acknowledge that estimates of species richness arise due to sampling. This compromises our ability to make ecological inferences from and about species–area relationships. We develop and illustrate hierarchical community models of abundance and frequency to estimate species richness. The models we propose separate sampling from ecological processes by explicitly accounting for the fact that sampled patches are seldom completely covered by sampling plots and that individuals present in the sampling plots are imperfectly detected. We propose a multispecies abundance model in which community assembly is treated as the summation of an ensemble of species-level Poisson processes and estimate patch-level species richness as a derived parameter. We use sampling process models appropriate for specific survey methods. We propose a multispecies frequency model that treats the number of plots in which a species occurs as a binomial process. We illustrate these models using data collected in surveys of early-successional bird species and plants in young forest plantation patches. Results indicate that only mature forest plant species deviated from the constant density hypothesis, but the null model suggested that the deviations were too small to alter the form of species–area relationships. Nevertheless, results from simulations clearly show that the aggregate pattern of individual species density–area relationships and occurrence probability–area relationships can alter the form of species–area relationships. The plant community model estimated that only half of the species present in the regional species pool were encountered during the survey. The modeling framework we propose explicitly accounts for sampling processes so that ecological processes can be examined free of sampling artefacts. Our modeling approach is extensible and could be applied

  11. Abundance, species composition of microzooplankton from the coastal waters of Port Blair, South Andaman Island

    PubMed Central

    2012-01-01

    Background Microzooplankton consisting of protists and metazoa <200 μm. It displays unique feeding mechanisms and behaviours that allow them to graze cells up to five times their own volume. They can grow at rates which equal or exceed prey growth and can serve as a viable food source for metazoans. Moreover, they are individually inconspicuous, their recognition as significant consumers of oceanic primary production. The microzooplankton can be the dominant consumers of phytoplankton production in both oligo- and eutrophic regions of the ocean and are capable of consuming >100% of primary production. Results The microzooplankton of the South Andaman Sea were investigated during September 2011 to January 2012. A total of 44 species belong to 19 genera were recorded in this study. Tintinnids made larger contribution to the total abundance (34%) followed in order by dinoflagellates (24%), ciliates (20%) and copepod nauplii (18%). Foraminifera were numerically less (4%). Tintinnids were represented by 20 species belong to 13 genera, Heterotrophic dinoflagellates were represented by 17 species belong to 3 genera and Ciliates comprised 5 species belong to 3 genera. Eutintinus tineus, Tintinnopsis cylindrical, T. incertum, Protoperidinium divergens, Lomaniella oviformes, Strombidium minimum were the most prevalent microzooplankton. Standing stock of tintinnids ranged from 30–80 cells.L-1 and showed a reverse distribution with the distribution of chlorophyll a relatively higher species diversity and equitability was found in polluted harbour areas. Conclusions The change of environmental variability affects the species composition and abundance of microzooplankton varied spatially and temporarily. The observations clearly demonstrated that the harbor area differed considerably from other area in terms of species present and phytoplankton biomass. Further, the phytoplankton abundance is showed to be strongly influenced by tintinnid with respect to the relationship of

  12. Abundance and phenology patterns of two pond-breeding salamanders determine species interactions in natural populations.

    PubMed

    Anderson, Thomas L; Hocking, Daniel J; Conner, Christopher A; Earl, Julia E; Harper, Elizabeth B; Osbourn, Michael S; Peterman, William E; Rittenhouse, Tracy A G; Semlitsch, Raymond D

    2015-03-01

    Phenology often determines the outcome of interspecific interactions, where early-arriving species often dominate interactions over those arriving later. The effects of phenology on species interactions are especially pronounced in aquatic systems, but the evidence is largely derived from experimental studies. We examined whether differences in breeding phenology between two pond-breeding salamanders (Ambystoma annulatum and A. maculatum) affected metamorph recruitment and demographic traits within natural populations, with the expectation that the fall-breeding A. annulatum would negatively affect the spring-breeding A. maculatum. We monitored populations of each species at five ponds over 4 years using drift fences. Metamorph abundance and survival of A. annulatum were affected by intra- and interspecific processes, whereas metamorph size and date of emigration were primarily influenced by intraspecific effects. Metamorph abundance, snout-vent length, date of emigration and survival for A. maculatum were all predicted by combinations of intra- and interspecific effects, but often showed negative relationships with A. annulatum metamorph traits and abundance. Size and date of metamorphosis were strongly correlated within each species, but in opposite patterns (negative for A. annulatum and positive for A. maculatum), suggesting that the two species use alternative strategies to enhance terrestrial survival and that these factors may influence their interactions. Our results match predictions from experimental studies that suggest recruitment is influenced by intra- and interspecific processes which are determined by phenological differences between species. Incorporating spatiotemporal variability when modeling population dynamics is necessary to understand the importance of phenology in species interactions, especially as shifts in phenology occur under climate change. PMID:25413866

  13. Species abundance distributions, statistical mechanics and the priors of MaxEnt.

    PubMed

    Bowler, M G

    2014-03-01

    The methods of Maximum Entropy have been deployed for some years to address the problem of species abundance distributions. In this approach, it is important to identify the correct weighting factors, or priors, to be applied before maximising the entropy function subject to constraints. The forms of such priors depend not only on the exact problem but can also depend on the way it is set up; priors are determined by the underlying dynamics of the complex system under consideration. The problem is one of statistical mechanics and it is the properties of the system that yield the correct MaxEnt priors, appropriate to the way the problem is framed. Here I calculate, in several different ways, the species abundance distribution resulting when individuals in a community are born and die independently. In the usual formulation the prior distribution for the number of species over the number of individuals is 1/n; the problem can be reformulated in terms of the distribution of individuals over species classes, with a uniform prior. Results are obtained using master equations for the dynamics and separately through the combinatoric methods of elementary statistical mechanics; the MaxEnt priors then emerge a posteriori. The first object is to establish the log series species abundance distribution as the outcome of per capita guild dynamics. The second is to clarify the true nature and origin of priors in the language of MaxEnt. Finally, I consider how it may come about that the distribution is similar to log series in the event that filled niches dominate species abundance. For the general ecologist, there are two messages. First, that species abundance distributions are determined largely by population sorting through fractional processes (resulting in the 1/n factor) and secondly that useful information is likely to be found only in departures from the log series. For the MaxEnt practitioner, the message is that the prior with respect to which the entropy is to be

  14. Relative distribution and abundance of fishes and crayfish in 2010 and 2014 prior to saltcedar (Tamarix ssp.) removal in the Amargosa River Canyon, southeastern California

    USGS Publications Warehouse

    Hereford, Mark E.

    2016-01-01

    The Amargosa River Canyon, located in the Mojave Desert of southeastern California, contains the longest perennial reach of the Amargosa River. Because of its diverse flora and fauna, it has been designated as an Area of Critical Environmental Concern and a Wild and Scenic River by the Bureau of Land Management. A survey of fishes conducted in summer 2010 indicated that endemic Amargosa River pupfish (Cyprinodon nevadensis amargosae) and speckled dace (Rhinichthys osculus spp.) were abundant and occurred throughout the Amargosa River Canyon. The 2010 survey reported non-native red swamp crayfish (Procambarus clarkii) and western mosquitofish (Gambusia affinis) captures were significantly higher, whereas pupfish captures were lower, in areas dominated by non-native saltcedar (Tamarix ssp.). Based on the 2010 survey, it was hypothesized that the invasion of saltcedar could result in a decrease in native species. In an effort to maintain and enhance native fish populations, the Bureau of Land Management removed saltcedar from a 1,550 meter reach of stream on the Amargosa River in autumn 2014 and autumn 2015. Prior to the removal of saltcedar, a survey of fishes and crayfish using baited minnow traps was conducted in the treatment reach to serve as a baseline for future comparisons with post-saltcedar removal surveys. During the 2014 survey, 1,073 pupfish and 960 speckled dace were captured within the treatment reach. Catch per unit effort of pupfish and speckled dace in the treatment reach was less in 2014 than in 2010, although differences could be owing to seasonal variation in capture probability. Non-native mosquitofish catch per unit effort decreased from 2010 to 2014; however, the catch per unit effort of crayfish increased from 2010 to 2014. Future monitoring efforts of this reach should be conducted at the same time period to account for potential seasonal fluctuations of abundance and distribution of fishes and crayfish. A more robust study design that

  15. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (South Atlantic): Black sea bass

    SciTech Connect

    Mercer, L.P.

    1989-07-01

    Species profiles are literature summaries on the taxonomy, morphology, range, life history, and environmental requirements of coastal aquatic species. They are designed to assist in environmental impact assessment. The black sea bass, Centropristis striata, is an abundant species associated with the inshore sponge-coral habitat in the South Atlantic Bight (Cape Hatteras to Cape Canaveral). It is a protogynous hermaphrodite (each individual is first a female and then a male) that spawns from January to June on the Continental shelf. Juveniles utilize estuaries, as well as offshore areas, for nurseries. It is a slow growing species with a life span of about 10 years. Juveniles and adults are bottom-feeding carnivores. Adults have been collected at temperatures as low as 6 /degree/C but are most abundant at temperatures of 8 to 10 /degree/C and above. Juveniles tolerate lower temperatures and greater salinity ranges than adults. Black sea bass are primarily harvested by the recreational hook and line fishery and the commercial trap fishery. Yield-per-recruit analyses indicate that the harvest of black sea bass is less than the maximum possible due to a combination of high fishing pressure and harvest of small fish. 58 refs., 2 figs., 6 tabs.

  16. Estimating forest species abundance through linear unmixing of CHRIS/PROBA imagery

    NASA Astrophysics Data System (ADS)

    Stagakis, Stavros; Vanikiotis, Theofilos; Sykioti, Olga

    2016-09-01

    The advancing technology of hyperspectral remote sensing offers the opportunity of accurate land cover characterization of complex natural environments. In this study, a linear spectral unmixing algorithm that incorporates a novel hierarchical Bayesian approach (BI-ICE) was applied on two spatially and temporally adjacent CHRIS/PROBA images over a forest in North Pindos National Park (Epirus, Greece). The scope is to investigate the potential of this algorithm to discriminate two different forest species (i.e. beech - Fagus sylvatica, pine - Pinus nigra) and produce accurate species-specific abundance maps. The unmixing results were evaluated in uniformly distributed plots across the test site using measured fractions of each species derived by very high resolution aerial orthophotos. Landsat-8 images were also used to produce a conventional discrete-type classification map of the test site. This map was used to define the exact borders of the test site and compare the thematic information of the two mapping approaches (discrete vs abundance mapping). The required ground truth information, regarding training and validation of the applied mapping methodologies, was collected during a field campaign across the study site. Abundance estimates reached very good overall accuracy (R2 = 0.98, RMSE = 0.06). The most significant source of error in our results was due to the shadowing effects that were very intense in some areas of the test site due to the low solar elevation during CHRIS acquisitions. It is also demonstrated that the two mapping approaches are in accordance across pure and dense forest areas, but the conventional classification map fails to describe the natural spatial gradients of each species and the actual species mixture across the test site. Overall, the BI-ICE algorithm presented increased potential to unmix challenging objects with high spectral similarity, such as different vegetation species, under real and not optimum acquisition conditions. Its

  17. Survey of parasitic fauna of different ornamental freshwater fish species in Iran.

    PubMed

    Adel, Milad; Ghasempour, Fatemeh; Azizi, Hamid Reza; Shateri, Mohamad Hadi; Safian, Ahmad Reza

    2015-01-01

    Parasitic diseases are harmful and limiting factors in breeding and rearing ornamental fish industry. In this study, 400 apparently healthy ornamental fishes from five species (each species 80 specimens) including: Goldfish (Carassius auratus), guppy (Poecilia reticulate), angelfish (Pterophyllum scalare), discus (Symphsodon discus) and sailfin mollies (Poecilia latipinna) was obtained from a local ornamental fish farm in the north of Iran during 2011 to 2012. The primary purpose of this study was to determine the parasitic infections of aquarium fish in Iran. For this purpose, fish were first examined for ectoparasites using wet mount under a light microscope. Then, the alimentary ducts of fish were observed under light and stereo microscope. In survey of different infection rates for different parasitic infections in examining fish: Dactylogyrus sp., Gyrodactylus sp., Ichthyophthirius multifiliis Trichodina reticulata, Capillaria sp. and Lernaea cyprinacea were collected from five species. All five fish species had Monogenea (Gyrodactylidae and Dactylogyridae) in their skins and gills, the highest prevalence was observed in C. auratus and the lowest was in P. scalare and S. discus. Also, Capillaria sp. was reported as a first record from the abdominal cavity of P. scalare in Iran. Our findings revealed that the protozoal infections are very common among aquarium fishes. Although, no gross pathology was observed among infected fishes, but it is likely that in case of any changes in the environment, then parasitic infections could be harmful. PMID:25992255

  18. Algal growth and species composition under experimental control of herbivory, phosphorus and coral abundance in Glovers Reef, Belize.

    PubMed

    McClanahan, T R; Cokos, B A; Sala, E

    2002-06-01

    The proliferation of algae on disturbed coral reefs has often been attributed to (1) a loss of large-bodied herbivorous fishes, (2) increases in sea water nutrient concentrations, particularly phosphorus, and (3) a loss of hard coral cover or a combination of these and other factors. We performed replicated small-scale caging experiments in the offshore lagoon of Glovers Reef atoll, Belize where three treatments had closed-top (no large-bodied herbivores) and one treatment had open-top cages (grazing by large-bodied herbivores). Closed-top treatments simulated a reduced-herbivory situation, excluding large fishes but including small herbivorous fishes such as damselfishes and small parrotfishes. Treatments in the closed-top cages included the addition of high phosphorus fertilizer, live branches of Acropora cervicornis and a third unmanipulated control treatment. Colonization, algal biomass and species composition on dead A. palmata "plates" were studied weekly for 50 days in each of the four treatments. Fertilization doubled the concentration of phosphorus from 0.35 to 0.77 microM. Closed-top cages, particularly the fertilizer and A. cervicornis additions, attracted more small-bodied parrotfish and damselfish than the open-top cages such that there was moderate levels of herbivory in closed-top cages. The open-top cages did, however, have a higher abundance of the chemically and morphologically defended erect algal species including Caulerpa cupressoides, Laurencia obtusa, Dictyota menstrualis and Lobophora variegata. The most herbivore-resistant calcareous green algae (i.e. Halimeda) were, however, uncommon in all treatments. Algal biomass increased and fluctuated simultaneously in all treatments over time, but algal biomass, as measured by wet, dry and decalcified weight, did not differ greatly between the treatments with only marginally higher biomass (p < 0.06) in the fertilized compared to open-top cages. Algal species composition was influenced by all

  19. Plankton studies in San Francisco Bay; II, Phytoplankton abundance and species composition, July 1977-December 1979

    USGS Publications Warehouse

    Wong, Raymond L. J.; Cloern, James E.

    1981-01-01

    Data are presented on the phytoplankton species composition and abundance in San Francisco Bay from July 1977 through December 1979. Phytoplankton identification and enumerations were made at selected stations. Sample collections were made at selected stations in the main channel of the Bay from Rio Vista on the Sacramento River to Calaveras Point in South San Francisco Bay, and at shoal stations in the central portion of South San Francisco Bay, San Pablo Bay, and Suisun Bay. Also reported, from October 1978 through December 1979, are the calculated phytoplankton carbon and percent nondiatom carbon, and the species list. This study is one component of an ongoing interdisciplinary study of San Francisco Bay. (USGS)

  20. Predicting probability of occurrence and factors affecting distribution and abundance of three Ozark endemic crayfish species at multiple spatial scales

    USGS Publications Warehouse

    Nolen, Matthew S.; Magoulick, Daniel D.; DiStefano, Robert J.; Imhoff, Emily M.; Wagner, Brian K.

    2014-01-01

    We found that a range of environmental variables were important in predicting crayfish distribution and abundance at multiple spatial scales and their importance was species-, response variable- and scale dependent. We would encourage others to examine the influence of spatial scale on species distribution and abundance patterns.

  1. Sampling designs matching species biology produce accurate and affordable abundance indices.

    PubMed

    Harris, Grant; Farley, Sean; Russell, Gareth J; Butler, Matthew J; Selinger, Jeff

    2013-01-01

    Wildlife biologists often use grid-based designs to sample animals and generate abundance estimates. Although sampling in grids is theoretically sound, in application, the method can be logistically difficult and expensive when sampling elusive species inhabiting extensive areas. These factors make it challenging to sample animals and meet the statistical assumption of all individuals having an equal probability of capture. Violating this assumption biases results. Does an alternative exist? Perhaps by sampling only where resources attract animals (i.e., targeted sampling), it would provide accurate abundance estimates more efficiently and affordably. However, biases from this approach would also arise if individuals have an unequal probability of capture, especially if some failed to visit the sampling area. Since most biological programs are resource limited, and acquiring abundance data drives many conservation and management applications, it becomes imperative to identify economical and informative sampling designs. Therefore, we evaluated abundance estimates generated from grid and targeted sampling designs using simulations based on geographic positioning system (GPS) data from 42 Alaskan brown bears (Ursus arctos). Migratory salmon drew brown bears from the wider landscape, concentrating them at anadromous streams. This provided a scenario for testing the targeted approach. Grid and targeted sampling varied by trap amount, location (traps placed randomly, systematically or by expert opinion), and traps stationary or moved between capture sessions. We began by identifying when to sample, and if bears had equal probability of capture. We compared abundance estimates against seven criteria: bias, precision, accuracy, effort, plus encounter rates, and probabilities of capture and recapture. One grid (49 km(2) cells) and one targeted configuration provided the most accurate results. Both placed traps by expert opinion and moved traps between capture sessions

  2. Sampling designs matching species biology produce accurate and affordable abundance indices

    PubMed Central

    Farley, Sean; Russell, Gareth J.; Butler, Matthew J.; Selinger, Jeff

    2013-01-01

    Wildlife biologists often use grid-based designs to sample animals and generate abundance estimates. Although sampling in grids is theoretically sound, in application, the method can be logistically difficult and expensive when sampling elusive species inhabiting extensive areas. These factors make it challenging to sample animals and meet the statistical assumption of all individuals having an equal probability of capture. Violating this assumption biases results. Does an alternative exist? Perhaps by sampling only where resources attract animals (i.e., targeted sampling), it would provide accurate abundance estimates more efficiently and affordably. However, biases from this approach would also arise if individuals have an unequal probability of capture, especially if some failed to visit the sampling area. Since most biological programs are resource limited, and acquiring abundance data drives many conservation and management applications, it becomes imperative to identify economical and informative sampling designs. Therefore, we evaluated abundance estimates generated from grid and targeted sampling designs using simulations based on geographic positioning system (GPS) data from 42 Alaskan brown bears (Ursus arctos). Migratory salmon drew brown bears from the wider landscape, concentrating them at anadromous streams. This provided a scenario for testing the targeted approach. Grid and targeted sampling varied by trap amount, location (traps placed randomly, systematically or by expert opinion), and traps stationary or moved between capture sessions. We began by identifying when to sample, and if bears had equal probability of capture. We compared abundance estimates against seven criteria: bias, precision, accuracy, effort, plus encounter rates, and probabilities of capture and recapture. One grid (49 km2 cells) and one targeted configuration provided the most accurate results. Both placed traps by expert opinion and moved traps between capture sessions, which

  3. Inter-annual variations in the abundance of young-of-the-year of migratory fishes in the Upper Paraná River floodplain: relations with hydrographic attributes.

    PubMed

    Suzuki, H I; Agostinho, A A; Bailly, D; Gimenes, M F; Júlio, H F; Gomes, L C

    2009-06-01

    In this study, we identified and characterized the hydrographic attributes related to the success of recruitment of migratory fishes in the Upper Paraná River floodplain. To achieve our objectives, we analyzed inter-annual variations in the abundance of young-of-the-year (YOY; index of recruitment) of six migratory species and their relations with hydrographic attributes. Recruitment was related to the intensity, duration (in different fluviometrical levels), elasticity, number of pulses, greater uninterrupted overflow and delay of the floods (all obtained using the PULSO software). Collections of fish were conducted in the period between January 1987 and November 2007 in distinct environments (river channels, secondary channels and connected and disconnected floodplain lakes) distributed along three subsystems (Paraná, Baía and Ivinheima). Relations between recruitment and the attributes of interest were determined through analysis of covariance. In the studied period, the highest abundances of YOY were registered in 2007, followed by 1992, 1993, 2005 and 1988. The abundance of YOY was positively correlated with an intensity of high water levels (potamophase) and the duration of potamophase 1 and negatively with the duration of low water levels (limnophase) and a delay of flood. Higher hydrometric levels (540 and 610 cm for Paraná and 325 and 450 cm for Ivinheima) and greatest uninterrupted overflow presented different relations (significant interactions) among subsystems, but all with positive effects on recruitment. Results evidenced that recruitment responded better when floods started in January with potamophase intensities above 610 cm and water levels above 450 cm over a period of 50 days and repeated every two years (or > 610 cm for 38 days and repeated every two or three years). Therefore, artificial control of the floods at intervals of two or three years by manipulating the discharge of dams located upstream from the floodplain in a way that promotes

  4. Patterns in Species Composition of Fish and Selected Invertebrate Assemblages in Estuarine Subregions near Ponce de Leon Inlet, Florida

    NASA Astrophysics Data System (ADS)

    Paperno, R.; Mille, K. J.; Kadison, E.

    2001-01-01

    The Florida Fish and Wildlife Conservation Commission's Fisheries-Independent Monitoring program monitored the species composition and relative abundance of fishes and selected invertebrates in the estuarine waters near Ponce de Leon Inlet, Florida, from January 1993 through to December 1996. Sampling sites were located in three distinct physiographic and biotic estuarine subregions: Mosquito Lagoon (ML; 11 stations), Ponce de Leon Inlet (PI; 8 stations), and Tomoka Basin/River (TR; 8 stations). This series of subregions associated with Ponce de Leon Inlet is a species-rich estuarine system that is numerically dominated by a few taxa. A total of 1 080 477 animals representing 160 species and 56 families were recorded. Anchoa spp. (29·9%) and Menidia spp. (12·6%) were the numerically dominant taxa. Sciaenidae and Gobiidae were the most speciose families, with 12 species each (14·0% and 1·7% of the total animals collected, respectively), followed by the bothids 10 species (0·6% of total animals). Detrended correspondence analysis showed that the subregions could be discriminated by their respective species composition and relative abundance. Spatial differences in species composition were principally attributed to differences in the magnitude of seasonal recruitment events and to habitat characteristics associated with the presence of seagrass, inlet dynamics, or the influence of freshwater discharge. The presence of freshwater taxa (centrarchids) and the seasonal recruitment of juvenile Penaeidae, Micropogonias undulatus , Stellifer lanceolatus and Leiostomus xanthurus, characterize the TR area, whereas the presence of species associated with higher salinities ( Opisthonema oglinum and Harengula jaguana) characterize PI and with seagrass ( Lucania parva and Lagodon rhomboides) characterize ML.

  5. Determing Lamprey Species Composition, Larval Distribution, and Adult Abundance in the Deschutes River, Oregon, Subbasin; 2001-2002 Annual Report.

    SciTech Connect

    Graham, Jennifer C.; Brun, Christopher V.

    2003-05-01

    Information about lamprey species composition, distribution, life history, abundance, habitat requirements and exploitation in lower Deschutes River tributaries is extremely limited. To assess the status of lampreys in the Deschutes River subbasin, baseline information is needed. We operated to rotary screw traps in the Warm Springs River and Shitike Creek to gain an understanding of species composition, migration time and production. We identified Pacific lampreys in two life stages, ammocoete and macropthalmia. It appears that Pacific lamprey macropthalmia out-migrate during winter in the Warm Springs River. We saw peak movements by ammocoetes in the spring in Shitike Creek and winter in the Warm Springs River. We found no relationship between stream discharge and the number of lamprey collected. Very few macropthalmia were collected in Shitike Creek. Ammocoete size in the Warm Springs River and Shitike Creek were different. The ammocoetes in the Shitike Creek trap were close in size to the macropthalmia collected in the Warm Springs River trap. We also completed planning and preparation for larval and associated habitat data collection. This preparation included purchasing necessary field equipment, selecting and marking sampling areas and attending training with US Fish and Wildlife Service (USFWS) and the Confederated Tribes of Umatilla Indian Reservation (CTUIR). Because lamprey identification is difficult we met with US Geological Survey (USGS) to assist us with larval lamprey identification techniques. We have also been working in coordination with the Oregon Department of Fish and Wildlife (ODFW) to prepare and implement creel surveys and a mark-recapture study at Sherar's Falls to estimate adult lamprey escapement.

  6. Species- and tissue-specific mercury bioaccumulation in five fish species from Laizhou Bay in the Bohai Sea of China

    NASA Astrophysics Data System (ADS)

    Liu, Jinhu; Cao, Liang; Huang, Wei; Dou, Shuozeng

    2013-05-01

    Mercury (Hg) concentrations in the tissues (muscle, stomach, liver, gills, skin, and gonads) of five fish species (mullet Liza ha em atocheil us, flathead fish Platycephalus indicus, sea bass Lateolabrax japonic u s, mackerel Scomberomorus niphonius and silver pomfret Pampus argenteus) collected from Laizhou Bay in the Bohai Sea of China were investigated. The results indicate that Hg bioaccumulation in the five fish was tissue-specific, with the highest levels in the muscle and liver, followed by the stomach and gonads. The lowest levels were found in the gills and skin. Fish at higher trophic levels (flathead fish and sea bass) exhibited higher Hg concentrations than consumers at lower trophic levels. Mercury bioaccumulation tended to be positively correlated with fish length in mullet, silver pomfret, mackerel, and flathead fish, but was negatively correlated with fish length in sea bass. The Hg concentrations in the muscles of all fish species in Laizhou Bay were within the permissible limits of food safety set by national and international criteria. However, the suggesting maximum consumption of sea bass is 263 g per week for human health.

  7. Comparative toxicity of 3-trifluormethyl-4-nitrophenol (TFM) to larval lampreys and eleven species of fishes

    USGS Publications Warehouse

    Applegate, Vernon C.; King, Everett L.

    1962-01-01

    The tolerances of larval lampreys, rainbow trout, and 10 species of warmwater fishes to 3-trifluormethyl-4-nitrophenol (TFM), a selective lamprey larvicide, were determined in three dilution waters of different physical and chemical characteristics. Differential toxic effects of the chemical to larval lampreys and test fishes varied broadly with the species of fish. Smallmouth bass and other centrarchids were most tolerant of the chemical; walleye, yellow perch, bullheads, and white suckers were most susceptible. The toxicity of TFM to both lampreys and fishes diminished as the conductivity and alkalinity of the dilution water increased. The differential action of the chemical was retained in all waters, however.

  8. Fish status survey of Nordic lakes: effects of acidification, eutrophication and stocking activity on present fish species composition.

    PubMed

    Tammi, Jouni; Appelberg, Magnus; Beier, Ulrika; Hesthagen, Trygve; Lappalainen, Antti; Rask, Martti

    2003-03-01

    The status of fish populations in 3821 lakes in Norway, Sweden and Finland was assessed in 1995-1997. The survey lakes were chosen by stratified random sampling from all (126 482) Fennoscandian lakes > or = 0.04 km2. The water chemistry of the lakes was analyzed and information on fish status was obtained by a postal inquiry. Fish population losses were most frequent in the most highly acidified region of southern Norway and least common in eastern Fennoscandia. According to the inquiry results, the number of lost stocks of brown trout (Salmo trutta), roach (Rutilus rutilus), Arctic char (Salvelinus alpinus) and perch (Perca fluviatilis) was estimated to exceed 10000. The number of stocks of these species potentially affected by the low alkalinity of lake water was estimated to exceed 11000. About 3300 lakes showed high total phosphorus (> 25 microg L(-1)) and cyprinid dominance in eastern Fennoscandia, notably southwestern Finland. This survey did not reveal any extinction of fish species due to eutrophication. One-third of the lakes had been artificially stocked with at least one new species, most often brown trout, whitefish (Coregonus lavaretus s.l.), Arctic char, rainbow trout (Oncorhynchus mykiss), pike-perch (Stizostedion lucioperca), grayling (Thymallus thymallus), pike (Esox lucius), bream (Abramis brama), tench (Tinca tinca) and European minnow (Phoxinus phoxinus). The number of artificially manipulated stocks of these species in Fennoscandian lakes was estimated to exceed 52000. Hence, the number of fish species occurring in Nordic lakes has recently been changed more by stockings than by losses of fish species through environmental changes such as acidification. PMID:12733793

  9. Shifts in Campylobacter species abundance may reflect general microbial community shifts in periodontitis progression

    PubMed Central

    Henne, Karsten; Fuchs, Felix; Kruth, Sebastian; Horz, Hans-Peter; Conrads, Georg

    2014-01-01

    Background Oral Campylobacter species have been found to be associated with periodontitis progression. While the etiological significance of Campylobacter rectus is quite established, the association of C. gracilis, C. concisus, and C. curvus with health or disease remains contradictory. Objectives This study hypothesizes that the proportion of species within the Campylobacter genus rather than the absolute abundance of a single species is a suitable indicator for periodontitis progression. Design Subgingival plaque from 90 periodontitis patients and gingival sulcus fluid of 32 healthy individuals were subjected to a newly developed nested PCR approach, in which all Campylobacter spp. were amplified simultaneously. The resulting mixture of 16S-rRNA-gene-amplicons were separated by single-stranded conformation polymorphism (SSCP) gel electrophoresis, followed by sequencing and identification of excised bands and relative quantification of band intensities. In all samples, the abundance of selected periodontitis marker species was determined based on DNA hybridization on a microarray. Results The highly prevalent Campylobacter community was composed of varying proportions of C. rectus, C. gracilis, C. concisus, and C. curvus. Cluster analysis based on SSCP-banding pattern resulted in distinct groups which in turn coincided with significant differences in abundance of established periodontitis marker species (Tannerella forsythia, Porphyromonas gingivalis, and Fusobacterium nucleatum) and progression. Conclusions The shift in the Campylobacter community composition seems to display the general microbial community shift during clinical progression in a simplified manner. The focus on members of the Campylobacter in this study suggests that this genus can be an indicator of ecological changes in the subgingival oral microflora. PMID:25412608

  10. Species abundance and diversity of Burkholderia cepacia complex in the environment.

    PubMed

    Ramette, Alban; LiPuma, John J; Tiedje, James M

    2005-03-01

    Despite considerable interest in studying Burkholderia cepacia complex in the environment, we still do not have efficient methods to detect, isolate, and screen large numbers of B. cepacia isolates. To better describe the ecology and diversity of B. cepacia complex, a colony hybridization assay was developed to detect specifically all species of the complex based on polymorphism of the variable V3 region of the 16S rRNA sequence. The sensitivity of the assay was dramatically enhanced by using a probe consisting of three repeats of a B. cepacia complex-specific probe, each separated by a phosphoramidite spacer. In addition, a duplex PCR targeting B. cepacia complex-specific recA and 16S rRNA sequences was developed to enable a fast and reliable diagnostic assay for members of the complex. When applied to maize rhizosphere samples, colony hybridization results were in good agreement with those of most-probable-number duplex PCR, both indicating a >100-fold fluctuation of abundance between individual plants. Using restriction analysis of recA for a total of 285 confirmed isolates of the B. cepacia complex, up to seven B. cepacia complex species were identified; however, their diversity and abundance were not evenly distributed among individual plants, and several allelic variants were commonly found from the same rhizosphere sample. These results indicate that not only complex communities of B. cepacia complex species and closely related strains of the same species may coexist at high population levels but also species composition and abundance may dramatically vary between individual plants. PMID:15746318

  11. Proximate composition, energetic value, and relative abundance of prey fish from the inshore eastern Bering Sea: Implications for piscivorous predators

    USGS Publications Warehouse

    Ball, J.R.; Esler, Daniel; Schmutz, J.A.

    2007-01-01

    Changing ocean conditions and subsequent shifts in forage fish communities have been linked to numerical declines of some piscivorous marine birds and mammals in the North Pacific. However, limited information about fish communities is available for some regions, including nearshore waters of the eastern Bering Sea, where many piscivores reside. We determined proximate composition and energetic value of a suite of potential forage fish collected from an estuary on the Yukon-Kuskokwim Delta, Alaska, during 2002 and 2003. Across species, energy density ranged from 14.5 to 20.7 kJ g−1 dry mass and varied primarily as a function of lipid content. Total energy content was strongly influenced by body length and we provide species-specific predictive models of total energy based on this relationship; some models may be improved further by incorporating year and date effects. Based on observed energetic differences, we conclude that variation in fish size, quantity, and species composition of the prey community could have important consequences for piscivorous predators.

  12. Diatom species abundance and morphologically-based dissolution proxies in coastal Southern Ocean assemblages

    NASA Astrophysics Data System (ADS)

    Warnock, Jonathan P.; Scherer, Reed P.

    2015-07-01

    Taphonomic processes alter diatom assemblages in sediments, thus potentially negatively impacting paleoclimate records at various rates across space, time, and taxa. However, quantitative taphonomic data is rarely included in diatom-based paleoenvironmental reconstructions and no objective standard exists for comparing diatom dissolution in sediments recovered from marine depositional settings, including the Southern Ocean's opal belt. Furthermore, identifying changes to diatom dissolution through time can provide insight into the efficiency of both upper water column nutrient recycling and the biological pump. This is significant in that reactive metal proxies (e.g. Al, Ti) in the sediments only account for post-depositional dissolution, not the water column where the majority of dissolution occurs. In order to assess the range of variability of responses to dissolution in a typical Southern Ocean diatom community and provide a quantitative guideline for assessing taphonomic variability in diatoms recovered from core material, a sediment trap sample was subjected to controlled, serial dissolution. By evaluating dissolution-induced changes to diatom species' relative abundance, three preservational categories of diatoms have been identified: gracile, intermediate, and robust. The relative abundances of these categories can be used to establish a preservation grade for diatom assemblages. However, changes to the relative abundances of diatom species in sediment samples may reflect taphonomic or ecological factors. In order to address this complication, relative abundance changes have been tied to dissolution-induced morphological change to the areolae of Fragilariopsis curta, a significant sea-ice indicator in Southern Ocean sediments. This correlation allows differentiation between gracile species loss to dissolution versus ecological factors or sediment winnowing. These results mirror a similar morphological dissolution index from a parallel study utilizing

  13. Relative abundance and distribution of fishes and crayfish at Ash Meadows National Wildlife Refuge, Nye County, Nevada, 2010-11

    USGS Publications Warehouse

    Scoppettone, G.G.; Johnson, D.M.; Hereford, M.E.; Rissler, Peter; Fabes, Mark; Salgado, Antonio; Shea, Sean

    2012-01-01

    Habitat restoration that favors native species can help control non-native species (McShane and others, 2004; Scoppettone and others, 2005; Kennedy and others, 2006). Restoration of Carson Slough and its tributaries present an opportunity to promote habitat types that favor native species over non-natives. Historically, the majority of Ash Meadows spring systems were tributaries to Carson Slough. In 2007 and 2008, a survey of Ash Meadows spring systems was conducted to generate baseline information on the distribution of fishes throughout AMNWR (Scoppettone and others, 2011b). In this study, w

  14. Accumulation features of arsenic species in various fishes collected from coastal cities in Korea

    NASA Astrophysics Data System (ADS)

    Choi, Sung-Deuk; Son, Hee-Sik; Choi, Minkyu; Park, Min-Kyu

    2015-12-01

    In this study, 36 fish species were collected from three coastal cities in Korea to investigate levels and patterns of six arsenicals (arsenite: As (III), arsenate: As (V), arsenocholine: AsC, arsenobetaine: AsB, monomethylarsonic acid: MMA, and dimethylarsinic acid: DMA). The levels of ∑6 As in the different fish species varied substantially, ranging from 0.02 μg As/g ww (Islaeli carp) to 9.65 μg As/g ww (Skate ray) with a median of 0.40 μg As/g ww. All the arsenicals in marine fishes showed higher levels than those in freshwater fishes due to fish feed living in saline water. Overall, marine carnivorous fishes seem to be more contaminated with arsenic. For all the fish samples, AsB (mean fraction: 90.6%) was dominant among the six arsenicals, indicating biomethylation of inorganic arsenic and accumulation of AsB. Fish species with high water contents showed elevated levels of As (III), but there was no further significant correlations between arsenicals and water/lipid contents. Concentrations of As (V) were significantly lower than those of As (III), which implies that As (V) is reduced during biomethylation of inorganic arsenic. Consequently, we hypothesize that the toxicity of arsenic (mainly derived from As (III)) can be increased by the reduction of As (V), especially for the fish species with higher water contents.

  15. Epidemic disease decimates amphibian abundance, species diversity, and evolutionary history in the highlands of central Panama

    PubMed Central

    Crawford, Andrew J.; Lips, Karen R.; Bermingham, Eldredge

    2010-01-01

    Amphibian populations around the world are experiencing unprecedented declines attributed to a chytrid fungal pathogen, Batrachochytrium dendrobatidis. Despite the severity of the crisis, quantitative analyses of the effects of the epidemic on amphibian abundance and diversity have been unavailable as a result of the lack of equivalent data collected before and following disease outbreak. We present a community-level assessment combining long-term field surveys and DNA barcode data describing changes in abundance and evolutionary diversity within the amphibian community of El Copé, Panama, following a disease epidemic and mass-mortality event. The epidemic reduced taxonomic, lineage, and phylogenetic diversity similarly. We discovered that 30 species were lost, including five undescribed species, representing 41% of total amphibian lineage diversity in El Copé. These extirpations represented 33% of the evolutionary history of amphibians within the community, and variation in the degree of population loss and decline among species was random with respect to the community phylogeny. Our approach provides a fast, economical, and informative analysis of loss in a community whether measured by species or phylogenetic diversity. PMID:20643927

  16. Epidemic disease decimates amphibian abundance, species diversity, and evolutionary history in the highlands of central Panama.

    PubMed

    Crawford, Andrew J; Lips, Karen R; Bermingham, Eldredge

    2010-08-01

    Amphibian populations around the world are experiencing unprecedented declines attributed to a chytrid fungal pathogen, Batrachochytrium dendrobatidis. Despite the severity of the crisis, quantitative analyses of the effects of the epidemic on amphibian abundance and diversity have been unavailable as a result of the lack of equivalent data collected before and following disease outbreak. We present a community-level assessment combining long-term field surveys and DNA barcode data describing changes in abundance and evolutionary diversity within the amphibian community of El Copé, Panama, following a disease epidemic and mass-mortality event. The epidemic reduced taxonomic, lineage, and phylogenetic diversity similarly. We discovered that 30 species were lost, including five undescribed species, representing 41% of total amphibian lineage diversity in El Copé. These extirpations represented 33% of the evolutionary history of amphibians within the community, and variation in the degree of population loss and decline among species was random with respect to the community phylogeny. Our approach provides a fast, economical, and informative analysis of loss in a community whether measured by species or phylogenetic diversity. PMID:20643927

  17. Relative abundance and species richness of cerambycid beetles in partial cut and uncut bottomland hardwood forests

    USGS Publications Warehouse

    Newell, P.; King, S.

    2009-01-01

    Partial cutting techniques are increasingly advocated and used to create habitat for priority wildlife. However, partial cutting may or may not benefit species dependent on deadwood; harvesting can supplement coarse woody debris in the form of logging slash, but standing dead trees may be targeted for removal. We sampled cerambycid beetles during the spring and summer of 2006 and 2007 with canopy malaise traps in 1- and 2-year-old partial cut and uncut bottomland hardwood forests of Louisiana. We captured a total of 4195 cerambycid beetles representing 65 species. Relative abundance was higher in recent partial cuts than in uncut controls and with more dead trees in a plot. Total species richness and species composition were not different between treatments. The results suggest partial cuts with logging slash left on site increase the abundance of cerambycid beetles in the first few years after partial cutting and that both partial cuts and uncut forest should be included in the bottomland hardwood forest landscape.

  18. Understanding Long-Term Changes in Species Abundance Using a Niche-Based Approach

    PubMed Central

    Helaouët, Pierre; Beaugrand, Grégory; Edwards, Martin

    2013-01-01

    One of the major challenges to understanding population changes in ecology for assessment purposes is the difficulty in evaluating the suitability of an area for a given species. Here we used a new simple approach able to faithfully predict through time the abundance of two key zooplanktonic species by focusing on the relationship between the species’ environmental preferences and their observed abundances. The approach is applied to the marine copepods Calanus finmarchicus and C. helgolandicus as a case study characterising the multidecadal dynamics of the North Sea ecosystem. We removed all North Sea data from the Continuous Plankton Recorder (CPR) dataset and described for both species a simplified ecological niche using Sea Surface Temperature (SST) and CPR Phytoplankton Colour Index (PCI). We then modelled the dynamics of each species by associating the North Sea’s environmental parameters to the species’ ecological niches, thus creating a method to assess the suitability of this area. By using both C. finmarchicus and C. helgolandicus as indicators, the procedure reproduces the documented switches from cold to warm temperate states observed in the North Sea. PMID:24265757

  19. Loss of biodiversity in a conservation unit of the Brazilian Atlantic Forest: the effect of introducing non-native fish species.

    PubMed

    Fragoso-Moura, E N; Oporto, L T; Maia-Barbosa, P M; Barbosa, F A R

    2016-02-01

    The introduction of species has become an important problem for biodiversity and natural ecosystem conservation. The lake system of the middle Rio Doce (MG, Brazil) comprises c. 200 lakes at various conservation states, of which 50 are located within the Rio Doce State Park (PERD). Previous studies had verified several of these lakes suffered non-native fishes introductions and the presence of these species needs for the implementation of actions aiming at not only their control but also the preservation of the native species. This study discusses the effects of non-native fish species in the largest conservation unit of Atlantic Forest in Minas Gerais, southeast of Brazil, using data from 1983 to 2010 distributed as follow: data prior to 2006 were obtained from previous studies, and data from September 2006 to July 2010 were obtained in Lake Carioca at four sampling stations using gillnets, seine nets and sieve. A total of 17 fish species was collected (2006-2010) of which five were introduced species. Among the small to medium size native species (30 to 2000 mm standard length) seven had disappeared, two are new records and one was recaptured. The non-native species Cichla kelberi (peacock bass) and Pygocentrus nattereri (red piranha) are within the most abundant captured species. Integrated with other actions, such as those preventing new introductions, a selective fishing schedule is proposed as an alternative approach to improve the conservation management actions and the local and regional biodiversity maintenance. PMID:26909619

  20. Variation in Population Synchrony in a Multi-Species Seabird Community: Response to Changes in Predator Abundance.

    PubMed

    Robertson, Gail S; Bolton, Mark; Morrison, Paul; Monaghan, Pat

    2015-01-01

    Ecologically similar sympatric species, subject to typical environmental conditions, may be expected to exhibit synchronous temporal fluctuations in demographic parameters, while populations of dissimilar species might be expected to show less synchrony. Previous studies have tested for synchrony in different populations of single species, and those including data from more than one species have compared fluctuations in only one demographic parameter. We tested for synchrony in inter-annual changes in breeding population abundance and productivity among four tern species on Coquet Island, northeast England. We also examined how manipulation of one independent environmental variable (predator abundance) influenced temporal changes in ecologically similar and dissimilar tern species. Changes in breeding abundance and productivity of ecologically similar species (Arctic Sterna paradisaea, Common S. hirundo and Roseate Terns S. dougallii) were synchronous with one another over time, but not with a species with different foraging and breeding behaviour (Sandwich Terns Thalasseus sandvicensis). With respect to changes in predator abundance, there was no clear pattern. Roseate Tern abundance was negatively correlated with that of large gulls breeding on the island from 1975 to 2013, while Common Tern abundance was positively correlated with number of large gulls, and no significant correlations were found between large gull and Arctic and Sandwich Tern populations. Large gull abundance was negatively correlated with productivity of Arctic and Common Terns two years later, possibly due to predation risk after fledging, while no correlation with Roseate Tern productivity was found. The varying effect of predator abundance is most likely due to specific differences in the behaviour and ecology of even these closely-related species. Examining synchrony in multi-species assemblages improves our understanding of how whole communities react to long-term changes in the

  1. Variation in Population Synchrony in a Multi-Species Seabird Community: Response to Changes in Predator Abundance

    PubMed Central

    Robertson, Gail S.; Bolton, Mark; Morrison, Paul; Monaghan, Pat

    2015-01-01

    Ecologically similar sympatric species, subject to typical environmental conditions, may be expected to exhibit synchronous temporal fluctuations in demographic parameters, while populations of dissimilar species might be expected to show less synchrony. Previous studies have tested for synchrony in different populations of single species, and those including data from more than one species have compared fluctuations in only one demographic parameter. We tested for synchrony in inter-annual changes in breeding population abundance and productivity among four tern species on Coquet Island, northeast England. We also examined how manipulation of one independent environmental variable (predator abundance) influenced temporal changes in ecologically similar and dissimilar tern species. Changes in breeding abundance and productivity of ecologically similar species (Arctic Sterna paradisaea, Common S. hirundo and Roseate Terns S. dougallii) were synchronous with one another over time, but not with a species with different foraging and breeding behaviour (Sandwich Terns Thalasseus sandvicensis). With respect to changes in predator abundance, there was no clear pattern. Roseate Tern abundance was negatively correlated with that of large gulls breeding on the island from 1975 to 2013, while Common Tern abundance was positively correlated with number of large gulls, and no significant correlations were found between large gull and Arctic and Sandwich Tern populations. Large gull abundance was negatively correlated with productivity of Arctic and Common Terns two years later, possibly due to predation risk after fledging, while no correlation with Roseate Tern productivity was found. The varying effect of predator abundance is most likely due to specific differences in the behaviour and ecology of even these closely-related species. Examining synchrony in multi-species assemblages improves our understanding of how whole communities react to long-term changes in the

  2. Species-specific preferences of German recreational anglers for freshwater fishing experiences, with emphasis on the intrinsic utilities of fish stocking and wild fishes.

    PubMed

    Arlinghaus, R; Beardmore, B; Riepe, C; Meyerhoff, J; Pagel, T

    2014-12-01

    To answer the question, whether anglers have an intrinsic preference for stocking or a preference for catch outcomes (e.g. catch rates) believed to be maintained by stocking, a discrete choice experiment was conducted among a sample of anglers (n = 1335) in Lower Saxony, Germany. After controlling for catch aspects of the fishing experience, no significant influence of two stocking attributes (stocking frequency and composition of the catch in terms of wild v. hatchery fishes) on the utility gained from fishing was found for any of the freshwater species that were studied. It was concluded that the previously documented large appreciation of fish stocking by anglers may be indicative of an underlying preference for sufficiently high catches rather than reflect an intrinsic preference for stocking or the catching of wild fishes per se. PMID:25469949

  3. The Human Release Hypothesis for biological invasions: human activity as a determinant of the abundance of invasive plant species

    PubMed Central

    Zimmermann, Heike; Brandt, Patric; Fischer, Joern; Welk, Erik; von Wehrden, Henrik

    2014-01-01

    Research on biological invasions has increased rapidly over the past 30 years, generating numerous explanations of how species become invasive. While the mechanisms of invasive species establishment are well studied, the mechanisms driving abundance patterns (i.e. patterns of population density and population size) remain poorly understood. It is assumed that invasive species typically have higher abundances in their new environments than in their native ranges, and patterns of invasive species abundance differ between invaded regions. To explain differences in invasive species abundance, we propose the Human Release Hypothesis. In parallel to the established Enemy Release Hypothesis, this hypothesis states that the differences in abundance of invasive species are found between regions because population expansion is reduced in some regions through continuous land management and associated cutting of the invasive species. The Human Release Hypothesis does not negate other important drivers of species invasions, but rather should be considered as a potentially important complementary mechanism. We illustrate the hypothesis via a case study on an invasive rose species, and hypothesize which locations globally may be most likely to support high abundances of invasive species. We propose that more extensive empirical work on the Human Release Hypothesis could be useful to test its general applicability. PMID:25352979

  4. The Human Release Hypothesis for biological invasions: human activity as a determinant of the abundance of invasive plant species.

    PubMed

    Zimmermann, Heike; Brandt, Patric; Fischer, Joern; Welk, Erik; von Wehrden, Henrik

    2014-01-01

    Research on biological invasions has increased rapidly over the past 30 years, generating numerous explanations of how species become invasive. While the mechanisms of invasive species establishment are well studied, the mechanisms driving abundance patterns (i.e. patterns of population density and population size) remain poorly understood. It is assumed that invasive species typically have higher abundances in their new environments than in their native ranges, and patterns of invasive species abundance differ between invaded regions. To explain differences in invasive species abundance, we propose the Human Release Hypothesis. In parallel to the established Enemy Release Hypothesis, this hypothesis states that the differences in abundance of invasive species are found between regions because population expansion is reduced in some regions through continuous land management and associated cutting of the invasive species. The Human Release Hypothesis does not negate other important drivers of species invasions, but rather should be considered as a potentially important complementary mechanism. We illustrate the hypothesis via a case study on an invasive rose species, and hypothesize which locations globally may be most likely to support high abundances of invasive species. We propose that more extensive empirical work on the Human Release Hypothesis could be useful to test its general applicability. PMID:25352979

  5. Spatial and Temporal Entry Patterns of Fish Larvae into North Carolina Estuaries: Comparisons Among One Pelagic and Two Demersal Species

    NASA Astrophysics Data System (ADS)

    Joyeux, J.-C.

    1998-12-01

    A sampling programme targeting larvae of winter spawning fishes immigrating from the oceanic domain into the Pamlico-Albemarle Sounds system (NC, U.S.A.) was performed at the four major inlets of the lagoon system. Sampling yielded abundant catches of three species, a Clupeid (Atlantic menhaden,Brevoortia tyrannus) and two Sciaenids (Atlantic croaker,Micropogonias undulatusand spot,Leiostomus xanthurus). In this article, the author documents the differences in the mechanisms developed for estuarine recruitment among the three species. Abundance at the tidal inlets was dependent upon numerous factors, such as sampling month, inlet, luminosity, tide flow direction and depth. The spatial and temporal positioning of the larvae differed among the species and affected their capabilities to be transported through the inlets. More specifically, spot and croaker migrated vertically within the water column in accordance with the direction of the water flow. Sciaenids minimized the outwelling effects of ebb tides by migrating into the slowest ebbing currents, near the bottom. Menhaden did not rely on vertical migrations for estuarine transport and retention. For this species, landward transport is provided either when dusk and flood onset are coincident or through non-tidal flows developing under meteorological forcing. The Sciaenids were less, or not, dependent upon these conditions. In one inlet, the retention was dependent upon the strength of the flooding and ebbing flows. In this case, the retention of the pelagic species was lower than the retention of demersal species.

  6. Bacterial colonization and extinction on marine aggregates: stochastic model of species presence and abundance

    PubMed Central

    Kramer, Andrew M; Lyons, M Maille; Dobbs, Fred C; Drake, John M

    2013-01-01

    Organic aggregates provide a favorable habitat for aquatic microbes, are efficiently filtered by shellfish, and may play a major role in the dynamics of aquatic pathogens. Quantifying this role requires understanding how pathogen abundance in the water and aggregate size interact to determine the presence and abundance of pathogen cells on individual aggregates. We build upon current understanding of the dynamics of bacteria and bacterial grazers on aggregates to develop a model for the dynamics of a bacterial pathogen species. The model accounts for the importance of stochasticity and the balance between colonization and extinction. Simulation results suggest that while colonization increases linearly with background density and aggregate size, extinction rates are expected to be nonlinear on small aggregates in a low background density of the pathogen. Under these conditions, we predict lower probabilities of pathogen presence and reduced abundance on aggregates compared with predictions based solely on colonization. These results suggest that the importance of aggregates to the dynamics of aquatic bacterial pathogens may be dependent on the interaction between aggregate size and background pathogen density, and that these interactions are strongly influenced by ecological interactions and pathogen traits. The model provides testable predictions and can be a useful tool for exploring how species-specific differences in pathogen traits may alter the effect of aggregates on disease transmission. PMID:24340173

  7. Abundance and Spatial Dispersion of Rice Stem Borer Species in Kahama, Tanzania

    PubMed Central

    Leonard, Alfonce; Rwegasira, Gration M.

    2015-01-01

    Species diversity, abundance, and dispersion of rice stem borers in framer’s fields were studied in four major rice growing areas of Kahama District. Stem borer larvae were extracted from the damaged tillers in 16 quadrants established in each field. Adult Moths were trapped by light traps and collected in vials for identification. Results indicated the presence of Chilo partellus, Maliarpha separatella, and Sesamia calamistis in all study areas. The most abundant species was C. partellus (48.6%) followed by M. separatella (35.4%) and S. calamistis was least abundant (16.1%). Stem borers dispersion was aggregated along the edges of rice fields in three locations (wards) namely: Bulige, Chela, and Ngaya. The dispersion in the fourth ward, Kashishi was uniform as established from two of the three dispersion indices tested. Further studies would be required to establish the available alternative hosts, the extent of economic losses and the distribution of rice stem borers in the rest of the Lake zone of Tanzania. PMID:26411785

  8. Abundance and Spatial Dispersion of Rice Stem Borer Species in Kahama, Tanzania.

    PubMed

    Leonard, Alfonce; Rwegasira, Gration M

    2015-01-01

    Species diversity, abundance, and dispersion of rice stem borers in framer's fields were studied in four major rice growing areas of Kahama District. Stem borer larvae were extracted from the damaged tillers in 16 quadrants established in each field. Adult Moths were trapped by light traps and collected in vials for identification. Results indicated the presence of Chilo partellus, Maliarpha separatella, and Sesamia calamistis in all study areas. The most abundant species was C. partellus (48.6%) followed by M. separatella (35.4%) and S. calamistis was least abundant (16.1%). Stem borers dispersion was aggregated along the edges of rice fields in three locations (wards) namely: Bulige, Chela, and Ngaya. The dispersion in the fourth ward, Kashishi was uniform as established from two of the three dispersion indices tested. Further studies would be required to establish the available alternative hosts, the extent of economic losses and the distribution of rice stem borers in the rest of the Lake zone of Tanzania. PMID:26411785

  9. Integration of non-indigenous species within the interspecific abundance-occupancy relationship

    NASA Astrophysics Data System (ADS)

    Rigal, François; Whittaker, Robert J.; Triantis, Kostas A.; Borges, Paulo A. V.

    2013-04-01

    There is a broad consensus that habitat disturbance and introduction of non-indigenous species may dramatically modify community structure, particularly in insular ecosystems. However, it is less clear whether emergent macroecological patterns are similarly affected. The positive interspecific abundance-occupancy relationship (IAOR) is one of the most pervasive macroecological patterns, yet has rarely been analyzed for oceanic island assemblages. We use an extensive dataset for arthropods from six islands within the Azorean archipelago to test: (1) whether indigenous and non-indigenous species are distributed differently within the IAOR; and (2) to the extent that they are, can differences can be attributed to two indices of disturbance. We implemented modeling averaged methods using five of the most common IAOR models to derive an averaged IAOR fit for each island. After testing if species colonization status (indigenous versus non-indigenous) may explain the residuals of the IAOR, we identified true negative and positive outliers and tested the effect of colonization status on the likelihood of a species being a positive or negative outlier. We found that the indigenous and non-indigenous species are randomly distributed on both sides of the overall IAOR. Only for Flores Island, were non-indigenous species more aggregated than indigenous species. We were unable to detect a meaningful relationship between deviation from the IAOR and disturbance, despite the undoubted impact of both severe habitat loss and non-indigenous species on these oceanic islands. Our results show that the non-indigenous species have been integrated alongside indigenous species in the contemporary Azorean arthropod communities such that they are mostly undetectable by the study of the IAOR.

  10. Non-dioxin-like PCBs in ten different fish species from the Danube river in Serbia.

    PubMed

    Janković, Saša; Curčić, Marijana; Radičević, Tatjana; Stefanović, Srđan; Lenhardt, Mirjana; Durgo, Ksenija; Antonijević, Biljana

    2011-10-01

    This work has been developed to examine the level of non-dioxin-like (ndl) PCBs (28, 52, 101, 138, 153 and 180) in (a) ten different freshwater fish species from the Danube river, (b) two sampling points: up and downstream of the industrial zone of the city of Pancevo (ecological hot spot in Serbia) and (c) two time points i.e., in 2001 and 2006. Obtained results would serve to analyse spatial, temporal and congener profile characteristics of ndl PCBs cumulated in fish tissues due to environmental pollution. Sixty-four samples of the following species were collected: wels (Silirus glanus), pike (Esox lucius), bream (Abramis brama), crucian carp (Carassius carassius), pike pearch (Stizostedion lucioperca), barbel (Barbus barbus), tench (Tinca tinca), sterlet (Acipenser ruthenus L.), common carp (Cyprinus carpio) and bighead carp (Hypophthalmichthys nobilis). Gas chromatography coupled with electron capture detector was used for analysis of ndl PCBs. Total ndl PCBs content in upstream samples ranged from 2.7 to 98.1 ng/g and from 4.9 to 68.3 ng/g in 2001 and 2006, respectively. During the 5 years, ndl PCBs content increased significantly in downstream samples i.e., ndl PCBs varied from 13.7 to 46.1 ng/g and from 14.4 to 107.2 ng/g in 2001 and 2006, respectively. PCBs 138 and 180 were predominant congeners in 2001, while in 2006 the most abundant PCB congeners were 138 and 153. In 2006, the presence of PCB 28 and PCB 52 has indicated a recent contamination event. Data on continual monitoring of PCBs in all relevant environmental compartments together with appropriate biomonitoring data are expected to give comprehensive insight into the fate and behaviour profile of these contaminants. PMID:21161586

  11. Depletion of Abundant Sequences by Hybridization (DASH): using Cas9 to remove unwanted high-abundance species in sequencing libraries and molecular counting applications.

    PubMed

    Gu, W; Crawford, E D; O'Donovan, B D; Wilson, M R; Chow, E D; Retallack, H; DeRisi, J L

    2016-01-01

    Next-generation sequencing has generated a need for a broadly applicable method to remove unwanted high-abundance species prior to sequencing. We introduce DASH (Depletion of Abundant Sequences by Hybridization). Sequencing libraries are 'DASHed' with recombinant Cas9 protein complexed with a library of guide RNAs targeting unwanted species for cleavage, thus preventing them from consuming sequencing space. We demonstrate a more than 99 % reduction of mitochondrial rRNA in HeLa cells, and enrichment of pathogen sequences in patient samples. We also demonstrate an application of DASH in cancer. This simple method can be adapted for any sample type and increases sequencing yield without additional cost. PMID:26944702

  12. Does pH affect fish species richness when lake area is considered?

    USGS Publications Warehouse

    Rago, P.J.; Wiener, J.G.

    1986-01-01

    Numerous surveys have shown that fish species richness (number of species) is positively correlated with lake pH. However, species richness of fish communities is also correlated with lake size, and low-pH lakes are often small. Thus, conclusions drawn from examination of fish community structure relative to spatial (among- lake) variation in pH have been limited by uncertainties regarding the confounded effects of lake area. The authors used two statistical methods, analysis of covariance and a nonparametric blocked comparison test, to remove effects of lake area and compare fish species richness in low-pH and high-pH lakes. Data from six previous surveys of water chemistry and fish communities in lakes of Ontario and northern Wisconsin were examined. Lakes with low pH ( less than or equal to 6.0) contained significantly fewer fish species than lakes with high pH (> 6.0) when the effect of lake area was considered. A simple probabilistic model showed that the ability to detect differences in species richness is low when lake areas and the pool of potential colonizing species are small. The authors recommend the blocked comparison test for separating the effects of lake area and pH on species richness.

  13. 9 CFR 93.911 - Ports designated for the importation of live VHS-regulated fish species.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... of live VHS-regulated fish species. 93.911 Section 93.911 Animals and Animal Products ANIMAL AND... (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION OF CERTAIN ANIMALS, BIRDS, FISH, AND POULTRY, AND CERTAIN... Animal Species General Provisions for Vhs-Regulated Fish Species § 93.911 Ports designated for...

  14. 9 CFR 93.911 - Ports designated for the importation of live VHS-regulated fish species.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... of live VHS-regulated fish species. 93.911 Section 93.911 Animals and Animal Products ANIMAL AND... (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION OF CERTAIN ANIMALS, BIRDS, FISH, AND POULTRY, AND CERTAIN... Animal Species General Provisions for Vhs-Regulated Fish Species § 93.911 Ports designated for...

  15. 9 CFR 93.911 - Ports designated for the importation of live VHS-regulated fish species.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... of live VHS-regulated fish species. 93.911 Section 93.911 Animals and Animal Products ANIMAL AND... (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION OF CERTAIN ANIMALS, BIRDS, FISH, AND POULTRY, AND CERTAIN... Animal Species General Provisions for Vhs-Regulated Fish Species § 93.911 Ports designated for...

  16. 9 CFR 93.911 - Ports designated for the importation of live VHS-regulated fish species.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... of live VHS-regulated fish species. 93.911 Section 93.911 Animals and Animal Products ANIMAL AND... (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION OF CERTAIN ANIMALS, BIRDS, FISH, AND POULTRY, AND CERTAIN... Animal Species General Provisions for Vhs-Regulated Fish Species § 93.911 Ports designated for...

  17. 9 CFR 93.911 - Ports designated for the importation of live VHS-regulated fish species.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... of live VHS-regulated fish species. 93.911 Section 93.911 Animals and Animal Products ANIMAL AND... (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION OF CERTAIN ANIMALS, BIRDS, FISH, AND POULTRY, AND CERTAIN... Animal Species General Provisions for Vhs-Regulated Fish Species § 93.911 Ports designated for...

  18. Convergence and divergence in a long-term old-field succession: the importance of spatial scale and species abundance.

    PubMed

    Li, Shao-Peng; Cadotte, Marc W; Meiners, Scott J; Pu, Zhichao; Fukami, Tadashi; Jiang, Lin

    2016-09-01

    Whether plant communities in a given region converge towards a particular stable state during succession has long been debated, but rarely tested at a sufficiently long time scale. By analysing a 50-year continuous study of post-agricultural secondary succession in New Jersey, USA, we show that the extent of community convergence varies with the spatial scale and species abundance classes. At the larger field scale, abundance-based dissimilarities among communities decreased over time, indicating convergence of dominant species, whereas incidence-based dissimilarities showed little temporal tend, indicating no sign of convergence. In contrast, plots within each field diverged in both species composition and abundance. Abundance-based successional rates decreased over time, whereas rare species and herbaceous plants showed little change in temporal turnover rates. Initial abandonment conditions only influenced community structure early in succession. Overall, our findings provide strong evidence for scale and abundance dependence of stochastic and deterministic processes over old-field succession. PMID:27373449

  19. 76 FR 21858 - Endangered and Threatened Species; Take of Anadromous Fish

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-19

    ... probability-based sampling of aquatic habitat conditions and species diversity and abundance. This status and... National Oceanic and Atmospheric Administration RIN 0648-XA375 Endangered and Threatened Species; Take of... species listed under the Endangered Species Act (ESA) and to help guide management and...

  20. 78 FR 1201 - Endangered and Threatened Species; Take of Anadromous Fish

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-08

    ... steelhead abundance, status, distribution, diversity, species/ecological interactions, and behavior in the... National Oceanic and Atmospheric Administration RIN 0648-XC425 Endangered and Threatened Species; Take of... species listed under the Endangered Species Act (ESA) and to help guide management and...

  1. Long-term trends and variability in the larvae of Pacific sardine and associated fish species of the California Current region

    NASA Astrophysics Data System (ADS)

    Smith, Paul E.; Moser, H. Geoffrey

    2003-08-01

    Fifty-year ichthyoplankton and oceanographic time series of the California Cooperative Oceanic Fisheries Investigations were used to describe changes in larval fish abundance and associated habitat features in the Southern California Bight region, extending seaward to the limits of the California Current. The ichthyoplankton data set for this analysis was based on single tows taken at all CalCOFI survey stations occupied within the current sampling pattern from 1951 to 2000 and consisted of a total of 11,917 samples from which 1,365,988 fish larvae were identified. The analysis included data on habitat temperature, macrozooplankton volumes, and 14 taxa of larval fishes, some of commercial interest (Pacific sardine, Pacific hake, Pacific and jack mackerel, and rockfishes), and a group of important mesopelagic species that represent specific habitats in the California Current region. Data are presented in a series of graphs showing changes in average abundance, triennial abundance ratios, and normalized quarterly abundance (1988-2000 only). Larval data clearly track the decline and recovery of the Pacific sardine population. Mesopelagic larvae of southern offshore species had the greatest response to the regime shift of 1976-77, increasing markedly in the Southern California Bight region after 1977. Likewise, this group of species showed the greatest response to the 1957-59 El Niño. There was no consistent response in larval abundance of Subarctic-Transitional mesopelagic species and nearshore taxa to the 1976-77 regime shift. Most of the species showed a negative shift in triennial larval abundance ratios in relation to hypothesized 1989-90 and 1998-99 regime shifts. These changes are discussed in relation to changes in temperature and macrozooplankton volumes.

  2. Concentrations of microcystins in tissues of several fish species from freshwater reservoirs and ponds.

    PubMed

    Kopp, Radovan; Palíková, Miroslava; Adamovský, Ondřej; Ziková, Andrea; Navrátil, Stanislav; Kohoutek, Jiří; Mareš, Jan; Bláha, Luděk

    2013-12-01

    The aim of this study is to summarise the determination of concentrations of microcystins (MCs) in muscle and liver of freshwater fish species caught in stagnant waters of the Czech Republic. Within the years 2007-2009, 351 muscle samples and 291 liver samples of 16 freshwater fish species derived from four fishponds, and four water reservoirs were analysed. MCs were detected in 53 liver samples. The highest concentrations of microcystins were determined in liver samples of carnivorous fish species; 50.3 ng/g of fresh weight (FW) in perch (Perca fluviatilis) and 22.7 ng/g FW in pikeperch (Sander lucioperca). MCs in liver were detected in other five fish species; asp (Aspius aspius), pike (Esox lucius), common carp (Cyprinus carpio), grass carp (Ctenopharyngodon idella) and European eel (Anguilla anguilla). Concentrations of MCs in liver of nine fish species (European bream, whitefish, tench, silver carp, European catfish, roach, chub, crucian carp and rudd) were below the detection limit of 1.2-5.4 ng/g FW for different MC congeners. However, the concentrations of MCs in all muscle samples were below the detection limit. The assessment of MCs concentrations might be influenced by the detection method used. Due to the concentrations of MCs being below the detection limit in muscle samples of all fish species analysed, it seems that there might be a low potential threat for human health in case of fish muscle consumption. PMID:23756815

  3. Seasonal diet shifts of seven fish species in an Atlantic rainforest stream in Southeastern Brazil.

    PubMed

    Deus, C P; Petrere-Junior, M

    2003-11-01

    We analyzed the stomach contents of 116 individuals belonging to seven fishes species in order to investigate seasonal changes in feeding strategy and how trophic interactions between species affect community structure in an Atlantic rainforest stream in Southeastern Brazil. Oligosarcus hepsetus and Pimelodus sp. consumed fewer items during the winter. Phalloceros caudimaculatus switched feeding habits from detritus during summer to algae during winter. These examples are related to variations in food availability and species feeding selectivity. The highest diet overlap values, for most species, as measured using Schoener's index, were observed in summer, along with a species tendency to be more generalist. Feeding pattern variation may influence the fish community structure. PMID:15029369

  4. Gnathostoma infection in fish caught for local consumption in Nakhon Nayok Province, Thailand I. Prevalence and fish species.

    PubMed

    Rojekittikhun, Wichit; Chaiyasith, Tossapon; Nuamtanong, Supaporn; Komalamisra, Chalit

    2004-09-01

    Between August 2000 and August 2001, 12,216 fish of 73 species were purchased from several local markets in Nakhon Nayok Province, Thailand, and examined for the presence of Gnathostoma larvae. Almost all species were fresh-water fish that had grown naturally, rather than raised commercially. Eight species were found to be infected with gnathostome larvae. The overall prevalence was 5.1% (626/12,216) and a total of 5,969 larvae was recovered. The highest rate of infection (30.1 %) was found in Monopterus albus (swamp eel). The rates in the remaining infected fish were as follows: Anabas testudineus (climbing perch) 7.7%, Channa striata (striped snake-head fish) 7.4%, Clarius macrocephalus (Gunther's walking catfish) 6.7%, Channa micropeltes (giant snake-head fish) 5.1%, Channa lucius (blotched snake-head fish) 4.0%, Clarius batrachus (Batrachian walking catfish) 1.4%, and Ompok krattensis (butter sheatfish) 0.6%. The mean number of larvae/fish was highest in swamp eels (10.0 larvae/eel), and the maximum number of 698 larvae was recovered from one eel. The body sizes of the recovered G. spinigerum advanced third-stage larvae were 2.70-5.10 mm in length (average, 3.97+/-0.50 mm) and 0.29-0.60 mm in width (average, 0.40+/-0.04 mm). The average number of cephalic hooklets of the larvae from rows 1 to 4 were 41.8+/-0.5 (range, 40-43), 43.6+/-0.6 (range, 42-45), 46.1+/-0.9 (range, 44-48) and 49.3+/-0.7 (range, 48-51), respectively. PMID:15689060

  5. STUDIES ON THE SPECIES COMPOSITION AND RELATIVE ABUNDANCE OF MOSQUITOES OF MPIGI DISTRICT, CENTRAL UGANDA

    PubMed Central

    Mayanja, Martin; Mutebi, John-Paul; Crabtree, Mary B.; Ssenfuka, Fred; Muwawu, Teddy; Lutwama, Julius J.

    2015-01-01

    Prediction of arboviral disease outbreaks and planning for appropriate control interventions require knowledge of the mosquito vectors involved. Although mosquito surveys have been conducted in different regions of Uganda since the mid 30’s such studies have not been carried out in Mpigi District. In October 2011, we conducted mosquito collections in Mpigi district to determine species composition and relative abundance of the different species. The survey was conducted in four villages, Njeru, Ddela, Kiwumu and Nsumbain Kammengo sub-county, Mpigi district, Uganda. CDC light traps baited with dry ice (carbon dioxide) were used to capture adult mosquitoes. A total of 54,878 mosquitoes comprising 46 species from eight genera were collected. The dominant species at all sites was Coquilletidia (Coquilletidia) fuscopennata Theobald (n=38,059, 69%), followed by Coquillettidia (Coquillettidia) metallica Theobald (n=4,265, 7.8%). The number of species collected varied from 17 in the genus Culex to 1 in the genus Lutzia. Of the 46 species identified, arboviruses had previously been isolated from 28 (60.9%) suggesting a high potential for arboviral transmission and/or maintenance in Mpigi District. PMID:26346305

  6. Species succession and sustainability of the Great Lakes fish community

    USGS Publications Warehouse

    Eshenroder, Randy L.; Burnham-Curtis, Mary K.

    1999-01-01

    This article concentrates on the sustainability of the offshore pelagic and deepwater fish communities that were historically dominated by lake trout (Salvelinus namaycush). The causes of alteration in these fish communities (i.e., overfishing, introductions, and cultural eutrophication) were identified by Loftus and Regier (1972). Here we look at the ecology of these altered communities in relation to sustainability and discuss the need for restoration.

  7. Spatio-Temporal Dynamics of Exploited Groundfish Species Assemblages Faced to Environmental and Fishing Forcings: Insights from the Mauritanian Exclusive Economic Zone.

    PubMed

    Kidé, Saïkou Oumar; Manté, Claude; Dubroca, Laurent; Demarcq, Hervé; Mérigot, Bastien

    2015-01-01

    Environmental changes and human activities can have strong impacts on biodiversity and ecosystem functioning. This study investigates how, from a quantitative point of view, simultaneously both environmental and anthropogenic factors affect species composition and abundance of exploited groundfish assemblages (i.e. target and non-target species) at large spatio-temporal scales. We aim to investigate (1) the spatial and annual stability of groundfish assemblages, (2) relationships between these assemblages and structuring factors in order to better explain the dynamic of the assemblages' structure. The Mauritanian Exclusive Economic Zone (MEEZ) is of particular interest as it embeds a productive ecosystem due to upwelling, producing abundant and diverse resources which constitute an attractive socio-economic development. We applied the multi-variate and multi-table STATICO method on a data set consisting of 854 hauls collected during 14-years (1997-2010) from scientific trawl surveys (species abundance), logbooks of industrial fishery (fishing effort), sea surface temperature and chlorophyll a concentration as environmental variables. Our results showed that abiotic factors drove four main persistent fish assemblages. Overall, chlorophyll a concentration and sea surface temperature mainly influenced the structure of assemblages of coastal soft bottoms and those of the offshore near rocky bottoms where upwellings held. While highest levels of fishing effort were located in the northern permanent upwelling zone, effects of this variable on species composition and abundances of assemblages were relatively low, even if not negligible in some years and areas. The temporal trajectories between environmental and fishing conditions and assemblages did not match for all the entire time series analyzed in the MEEZ, but interestingly for some specific years and areas. The quantitative approach used in this work may provide to stakeholders, scientists and fishers a useful

  8. Spatio-Temporal Dynamics of Exploited Groundfish Species Assemblages Faced to Environmental and Fishing Forcings: Insights from the Mauritanian Exclusive Economic Zone

    PubMed Central

    Kidé, Saïkou Oumar; Manté, Claude; Dubroca, Laurent; Demarcq, Hervé; Mérigot, Bastien

    2015-01-01

    Environmental changes and human activities can have strong impacts on biodiversity and ecosystem functioning. This study investigates how, from a quantitative point of view, simultaneously both environmental and anthropogenic factors affect species composition and abundance of exploited groundfish assemblages (i.e. target and non-target species) at large spatio-temporal scales. We aim to investigate (1) the spatial and annual stability of groundfish assemblages, (2) relationships between these assemblages and structuring factors in order to better explain the dynamic of the assemblages’ structure. The Mauritanian Exclusive Economic Zone (MEEZ) is of particular interest as it embeds a productive ecosystem due to upwelling, producing abundant and diverse resources which constitute an attractive socio-economic development. We applied the multi-variate and multi-table STATICO method on a data set consisting of 854 hauls collected during 14-years (1997–2010) from scientific trawl surveys (species abundance), logbooks of industrial fishery (fishing effort), sea surface temperature and chlorophyll a concentration as environmental variables. Our results showed that abiotic factors drove four main persistent fish assemblages. Overall, chlorophyll a concentration and sea surface temperature mainly influenced the structure of assemblages of coastal soft bottoms and those of the offshore near rocky bottoms where upwellings held. While highest levels of fishing effort were located in the northern permanent upwelling zone, effects of this variable on species composition and abundances of assemblages were relatively low, even if not negligible in some years and areas. The temporal trajectories between environmental and fishing conditions and assemblages did not match for all the entire time series analyzed in the MEEZ, but interestingly for some specific years and areas. The quantitative approach used in this work may provide to stakeholders, scientists and fishers a useful

  9. Abundance of Woody Riparian Species in the Western USA in Relation to Phenology, Climate, and Flow Regime

    NASA Astrophysics Data System (ADS)

    Auble, G. T.; Friedman, J. M.; Scott, M. L.; Shafroth, P. B.; Merigliano, M. M.; Freehling, M. D.; Evans, R. E.; Griffin, E. R.

    2004-12-01

    We randomly selected 475 long-term U.S. Geological Survey stream gaging stations in 17 western states to relate the presence and abundance of woody species to environmental factors. Along a 1.3-km reach near each station we measured the cover of all species on a list of the 44 most abundant large woody riparian species in the region. We used logistic regression to fit the response of four abundant species to growing degree days and mean precipitation. Then we related relative abundance of these 4 species to timing of the flood peak in sites where the likelihood of occurrence was greater than 0.5. The exotics Tamarix ramosissima (saltcedar) and Elaeagnus angustifolia (Russian-olive) are now the third and fourth most frequently occurring large woody riparian species in the western U.S. and the second and fifth most abundant. In climatically suitable areas, species differences in reproductive phenology produce different relations of abundance to flow regime. Because of its limited period of seed release and viability in early summer, cottonwood (Populus deltoides) is disadvantaged where floods occur in the spring or fall. Abundances of saltcedar, because of its long period of seed release; Russian-olive, because of seed dormancy; and Salix exigua, because of the importance of vegetative spread, are much less sensitive to flood timing.

  10. Assessing Landscape Constraints on Species Abundance: Does the Neighborhood Limit Species Response to Local Habitat Conservation Programs?

    PubMed Central

    Jorgensen, Christopher F.; Powell, Larkin A.; Lusk, Jeffery J.; Bishop, Andrew A.; Fontaine, Joseph J.

    2014-01-01

    Landscapes in agricultural systems continue to undergo significant change, and the loss of biodiversity is an ever-increasing threat. Although habitat restoration is beneficial, management actions do not always result in the desired outcome. Managers must understand why management actions fail; yet, past studies have focused on assessing habitat attributes at a single spatial scale, and often fail to consider the importance of ecological mechanisms that act across spatial scales. We located survey sites across southern Nebraska, USA and conducted point counts to estimate Ring-necked Pheasant abundance, an economically important species to the region, while simultaneously quantifying landscape effects using a geographic information system. To identify suitable areas for allocating limited management resources, we assessed land cover relationships to our counts using a Bayesian binomial-Poisson hierarchical model to construct predictive Species Distribution Models of relative abundance. Our results indicated that landscape scale land cover variables severely constrained or, alternatively, facilitated the positive effects of local land management for Ring-necked Pheasants. PMID:24918779

  11. Assessing landscape constraints on species abundance: does the neighborhood limit species response to local habitat conservation programs?

    PubMed

    Jorgensen, Christopher F; Powell, Larkin A; Lusk, Jeffery J; Bishop, Andrew A; Fontaine, Joseph J

    2014-01-01

    Landscapes in agricultural systems continue to undergo significant change, and the loss of biodiversity is an ever-increasing threat. Although habitat restoration is beneficial, management actions do not always result in the desired outcome. Managers must understand why management actions fail; yet, past studies have focused on assessing habitat attributes at a single spatial scale, and often fail to consider the importance of ecological mechanisms that act across spatial scales. We located survey sites across southern Nebraska, USA and conducted point counts to estimate Ring-necked Pheasant abundance, an economically important species to the region, while simultaneously quantifying landscape effects using a geographic information system. To identify suitable areas for allocating limited management resources, we assessed land cover relationships to our counts using a Bayesian binomial-Poisson hierarchical model to construct predictive Species Distribution Models of relative abundance. Our results indicated that landscape scale land cover variables severely constrained or, alternatively, facilitated the positive effects of local land management for Ring-necked Pheasants. PMID:24918779

  12. Distribution and abundance of decapod crustacean larvae in the southeastern Bering Sea with emphasis on commercial species. Final report

    SciTech Connect

    Armstrong, D.A.; Incze, L.S.; Wencker, D.L.; Armstrong, J.L.

    1981-01-01

    Contents include: Distribution and abundance of king crab larvae, Paralithodes camtschatica and P. platypus in the southeast Bering Sea; Distribution and abundance of the larvae of tanner crabs in the southeastern Bering Sea; Distribution and abundance of other brachyuran larvae in the southeastern Bering Sea with emphasis on Erimacrus isenbeckii; Distribution and abundance of shrimp larvae in the southeastern Bering Sea with emphasis on pandalid species; Distribution and abundance of hermit crabs (Paguridae) in the southeasternBering Sea; Possible oil impacts on decapod larbae in the southeastern Bering Sea with emphesis on the St. George Basin.

  13. Stream salamander species richness and abundance in relation to environmental factors in Shenandoah National Park, Virginia

    USGS Publications Warehouse

    Grant, E.H.C.; Jung, R.E.; Rice, K.C.

    2005-01-01

    Stream salamanders are sensitive to acid mine drainage and may be sensitive to acidification and low acid neutralizing capacity (ANC) of a watershed. Streams in Shenandoah National Park, Virginia, are subject to episodic acidification from precipitation events. We surveyed 25 m by 2 m transects located on the stream bank adjacent to the water channel in Shenandoah National Park for salamanders using a stratified random sampling design based on elevation, aspect and bedrock geology. We investigated the relationships of four species (Eurycea bislineata, Desmognathus fuscus, D. monticola and Gyrinophilus porphyriticus) to habitat and water quality variables. We did not find overwhelming evidence that stream salamanders are affected by the acid-base status of streams in Shenandoah National Park. Desmognathus fuscus and D. monticola abundance was greater both in streams that had a higher potential to neutralize acidification, and in higher elevation (>700 m) streams. Neither abundance of E. bislineata nor species richness were related to any of the habitat variables. Our sampling method preferentially detected the adult age class of the study species and did not allow us to estimate population sizes. We suggest that continued monitoring of stream salamander populations in SNP will determine the effects of stream acidification on these taxa.

  14. Monitoring species richness and abundance of shorebirds in the western Great Basin

    USGS Publications Warehouse

    Warnock, N.; Haig, Susan M.; Oring, L.W.

    1998-01-01

    Broad-scale avian surveys have been attempted within North America with mixed results. Arid regions, such as the Great Basin, are often poorly sampled because of the vastness of the region, inaccessibility of sites, and few ornithologists. In addition, extreme variability in wetland habitat conditions present special problems for conducting censuses of species inhabiting these areas. We examined these issues in assessing multi-scale shorebird (order: Charadriiformes) censuses conducted in the western Great Basin from 1992-1997. On ground surveys, we recorded 31 species of shorebirds, but were unable to accurately estimate population size. Conversely, on aerial surveys we were able to estimate regional abundance of some shorebirds, but were unable to determine species diversity. Aerial surveys of three large alkali lakes in Oregon (Goose, Summer, and Abert Lakes) revealed > 300,000 shorebirds in one year of this study, of which 67% were American Avocets (Recurvirostra americana) and 30% phalaropes (Phalaropus spp.). These lakes clearly meet Western Hemisphere Shorebird Reserve Network guidelines for designation as important shorebird sites. Based upon simulations of our monitoring effort and the magnitude and variation of numbers of American Avocets, detection of S-10% negative declines in populations of these birds would take a minimum of 7-23 years of comparable effort. We conclude that a combination of ground and aerial surveys must be conducted at multiple sites and years and over a large region to obtain an accurate picture of the diversity, abundance, and trends of shorebirds in the western Great Basin.

  15. Monitoring species richness and abundance of shorebirds in the western Great Basin

    USGS Publications Warehouse

    Warnock, N.; Haig, S.M.; Oring, L.W.

    1998-01-01

    Broad-scale avian surveys have been attempted within North America with mixed results. Arid regions, such as the Great Basin, are often poorly sampled because of the vastness of the region, inacessibilty of sites, and few ornithologist. In addition, extreme variability in wetland habitat conditions present special problems for conducting censuses of species inhabiting these areas. We examined these issues in assessing multi-scale shorebird (order: Charadriiformes) censuses conducted the western Great Basin from 1992-1997. On ground surveys, we recorded 31 species of shorebirds, but were unable to accurately estimate population size. Conversely, on aerial surveys we were able to estimate regional abundance of some shorebirds, but were unable to determined species diversity. Acrial surveys of three large alkali lakcs in Oregon (Goose, Summer, and abert Lakes) revealed > 300,000 shorebirds in one year of this study, of which 67% were American Avocets (Recurvirostra americana) and 30% phalaropes (Phalaropus spp.). These lakes clearly meet Western Hemisphere Shorebird Reserve Network guidelines for designation as important shorebirds sites. Based upon simulations of our monitoring effort and the magnitude and variation of numbers of American Avocets, detection of 5-10% negative declines in population of these birds would take a minimum of 7-23 years comparable effort. We conclude that a combination of ground and aerial surveys must be conducted at multiple sites and years and over a large region to obtain an accurate picture of the diversity, abundance, and trends of shorebirds in the western Great Basin.

  16. Connecting ground water influxes with fish species diversity in an urbanized watershed

    USGS Publications Warehouse

    Steffy, L.Y.; McGinty, A.L.; Welty, C.; Kilham, S.S.

    2004-01-01

    Valley Creek watershed is a small stream system that feeds the Schuylkill River near Philadelphia, Pennsylvania. The watershed is highly urbanized, including over 17 percent impervious surface cover (ISC) by area. Imperviousness in a watershed has been linked to fish community structure and integrity. Generally, above 10 to 12 percent ISC there is marked decline in fish assemblages with fish being absent above 25 percent ISC. This study quantifies the importance of ground water in maintaining fish species diversity in subbasins with over 30 percent ISC. Valley Creek contains an atypical fish assemblage in that the majority of the fish are warm-water species, and the stream supports naturally reproducing brown trout, which were introduced and stocked from the early 1900s to 1985. Fish communities were quantified at 13 stations throughout the watershed, and Simpson's species diversity index was calculated. One hundred and nine springs were located, and their flow rates measured. A cross covariance analysis between Simpson's species diversity index and spring flow rates upstream of fish stations was performed to quantify the spatial correlation between these two variables. The correlation was found to be highest at lag distances up to about 400 m and drop off significantly beyond lag distances of about 800 m.

  17. OCCURRENCE OF TWO LEECH SPECIES (ANNELIDA: HIRUDINEA) ON FISHES IN THE KENTUCKY RIVER

    EPA Science Inventory

    Little is known specifically on the feeding relationships between parasitic leeches and fish in North America. During an electrofishing survey conducted on the main stem of the Kentucky River in the summer of 2000, the presence of leeches was documented on six species of fish. ...

  18. 78 FR 77659 - Endangered and Threatened Species; Take of Anadromous Fish

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-24

    ... (16344) was published in the Federal Register on April 14, 2011 (76 FR 20956). Permit 16344 was issued to... Anadromous Fish AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... CFR parts 222-226) governing listed fish and wildlife permits. ] Species Covered in This Notice...

  19. 75 FR 33243 - Endangered and Threatened Species; Take of An