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Sample records for fish communities evolution

  1. Community Evolution

    CERN Document Server

    Bródka, Piotr; Kazienko, Przemysław

    2016-01-01

    The continuous interest in the social network area contributes to the fast development of this field. The new possibilities of obtaining and storing data facilitate deeper analysis of the entire social network, extracted social groups and single individuals as well. One of the most interesting research topic is the network dynamics and dynamics of social groups in particular, it means analysis of group evolution over time. It is the natural step forward after social community extraction. Having communities extracted, appropriate knowledge and methods for dynamic analysis may be applied in order to identify changes as well as to predict the future of all or some selected groups. Furthermore, knowing the most probably change of a given group some additional steps may be performed in order to change this predicted future according to specific needs. Such ability would be a powerful tool in the hands of human resource managers, personnel recruitment, marketing, telecommunication companies, etc.

  2. Fishing Community Profiles

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To enable fisheries managers to comply with National Standard 8 (NS8), NMFS social scientists around the nation are preparing fishing community profiles that present...

  3. The offshore benthic fish community

    Science.gov (United States)

    Lantry, Brian F.; Lantry, Jana R.; Weidel, Brian C.; Walsh, Maureen; Hoyle, James A.; Schaner, Teodore; Neave, Fraser B.; Keir, Michael

    2014-01-01

    Lake Ontario’s offshore benthic fish community includes primarily slimy sculpin, lake whitefish, rainbow smelt, lake trout, burbot, and sea lamprey. Of these, lake trout have been the focus of an international restoration effort for more than three decades (Elrod et al. 1995; Lantry and Lantry 2008). The deepwater sculpin and three species of deepwater ciscoes (Coregonus spp.) that were historically important in the offshore benthic zone became rare or were extirpated by the 1960s (Christie 1973; Owens et al. 2003; Lantry et al. 2007b; Roth et al. 2013). Ecosystem changes continue to influence the offshore benthic fish community, including the effects of dreissenid mussels, the near disappearance of burrowing amphipods (Diporeia spp.) (Dermott et al. 2005; Watkins et al. 2007), and the increased abundance and expanded geographic distribution of round goby (see Nearshore Fish Community chapter) (Lantry et al. 2007b). The fish-community objectives for the offshore benthic fish community, as described by Stewart et al. (1999), are:

  4. Offshore Fish Community: Ecological Interactions

    Science.gov (United States)

    The offshore (>80 m) fish community of Lake Superior is made up of predominately native species. The most prominent species are deepwater sculpin, kiyi, cisco, siscowet lake trout, burbot, and the exotic sea lamprey. Bloater and shortjaw cisco are also found in the offshore zone...

  5. Fishing degrades size structure of coral reef fish communities.

    Science.gov (United States)

    Robinson, James P W; Williams, Ivor D; Edwards, Andrew M; McPherson, Jana; Yeager, Lauren; Vigliola, Laurent; Brainard, Russell E; Baum, Julia K

    2017-03-01

    Fishing pressure on coral reef ecosystems has been frequently linked to reductions of large fishes and reef fish biomass. Associated impacts on overall community structure are, however, less clear. In size-structured aquatic ecosystems, fishing impacts are commonly quantified using size spectra, which describe the distribution of individual body sizes within a community. We examined the size spectra and biomass of coral reef fish communities at 38 US-affiliated Pacific islands that ranged in human presence from near pristine to human population centers. Size spectra 'steepened' steadily with increasing human population and proximity to market due to a reduction in the relative biomass of large fishes and an increase in the dominance of small fishes. Reef fish biomass was substantially lower on inhabited islands than uninhabited ones, even at inhabited islands with the lowest levels of human presence. We found that on populated islands size spectra exponents decreased (analogous to size spectra steepening) linearly with declining biomass, whereas on uninhabited islands there was no relationship. Size spectra were steeper in regions of low sea surface temperature but were insensitive to variation in other environmental and geomorphic covariates. In contrast, reef fish biomass was highly sensitive to oceanographic conditions, being influenced by both oceanic productivity and sea surface temperature. Our results suggest that community size structure may be a more robust indicator than fish biomass to increasing human presence and that size spectra are reliable indicators of exploitation impacts across regions of different fish community compositions, environmental drivers, and fisheries types. Size-based approaches that link directly to functional properties of fish communities, and are relatively insensitive to abiotic variation across biogeographic regions, offer great potential for developing our understanding of fishing impacts in coral reef ecosystems. © 2016

  6. 85 million years of pelagic ecosystem evolution: Pacific Ocean deep-sea ichthyolith records reveal fish community dynamics and a long-term decline in sharks

    Science.gov (United States)

    Sibert, E. C.; Norris, R. D.; Cuevas, J. M.; Graves, L. G.

    2015-12-01

    The structure and productivity of open ocean consumers has undergone major changes over the past 85 million years. Here, we present the first long-term detailed records of pelagic fish and sharks utilizing the record of ichthyoliths (teeth and dermal scales) from the deep Pacific Ocean. While the North and South Pacific Oceans show similar patterns throughout the 85 million year history, the North Pacific ichthyolith accumulation is significantly higher than the South Pacific, suggesting that the basin has been a more productive region for tens of millions of years. Fish and sharks were not abundant in the Pacific gyres until ~75 million years ago (Ma) suggesting that neither group was quantitatively important in oligotrophic pelagic food webs prior to the latest Cretaceous. Relative to ray-finned fish, sharks were common in the ancient ocean. Most ichthyolith assemblages have >50% shark dermal scales (denticles), but denticle abundance has been declining in both absolute and relative abundance since the Cretaceous-Paleogene (K/Pg) mass extinction. The accumulation rate of ichthyoliths of both sharks and ray-finned fish was highest in the Early Eocene, during the peak of the Cenozoic 'greenhouse' climate where production of shark dermal denticles and fish teeth increased almost five times over Paleocene production rates. Ichthyolith fluxes fell with cooler climates in the later Eocene and Oligocene, but fish production is almost always higher than in the Cretaceous and Paleocene reflecting the expanded ecological roles and importance of pelagic fish in marine ecosystems. Shark denticle production fell to less than half that of the Cretaceous by 20 Ma when it dropped abruptly to near-zero levels. Currently denticles make up sharks appear to be falling as major pelagic consumers over the Late Cretaceous and Cenozoic, and particularly over the past 20 Ma, perhaps reflecting demographic changes in shark and fish communities, or the rise of resource competition from

  7. Hybrid seine for full fish community collections

    Science.gov (United States)

    McKenna, James E.; Waldt, Emily M.; Abbett, Ross; David, Anthony; Snyder, James

    2013-01-01

    Seines are simple and effective fish collection gears, but the net mesh size influences how well the catch represents the fish communities. We designed and tested a hybrid seine with a dual-mesh bag (1/4″ and 1/8″) and compared the fish assemblage collected by each mesh. The fine-mesh net retained three times as many fish and collected more species (as many as eight), including representatives of several rare species, than did the coarser mesh. The dual-mesh bag permitted us to compare both sizes and species retained by each layer and to develop species-specific abundance correction factors, which allowed comparison of catches with the coarse-mesh seine used for earlier collections. The results indicate that a hybrid seine with coarse-mesh wings and a fine-mesh bag would enhance future studies of fish communities, especially when small-bodied fishes or early life stages are the research focus.

  8. Molecular epidemiology and evolution of fish Novirhabdoviruses

    Science.gov (United States)

    Kurath, Gael

    2014-01-01

    The genus Novirhabdoviridae contains several of the important rhabdoviruses that infect fish hosts. There are four established virus species: Infectious hematopoietic necrosis virus (IHNV), Viral hemorrhagic septicemia virus (VHSV), Hirame rhabdovirus(HIRRV), and Snakehead rhabdovirus (SHRV). Viruses of these species vary in host and geographic range, and they have all been studied at the molecular and genomic level. As globally significant pathogens of cultured fish, IHNV and VHSV have been particularly well studied in terms of molecular epidemiology and evolution. Phylogenic analyses of hundreds of field isolates have defined five major genogroups of IHNV and four major genotypes of VHSV worldwide. These phylogenies are informed by the known histories of IHNV and VHSV, each involving a series of viral emergence events that are sometimes associated with host switches, most often into cultured rainbow trout. In general, IHNV has relatively low genetic diversity and a narrow host range, and has been spread from its endemic source in North American to Europe and Asia due to aquaculture activities. In contrast, VHSV has broad host range and high genetic diversity, and the source of emergence events is virus in widespread marine fish reservoirs in the northern Atlantic and Pacific Oceans. Common mechanisms of emergence and host switch events include use of raw feed, proximity to wild fish reservoirs of virus, and geographic translocations of virus or naive fish hosts associated with aquaculture.

  9. Convergent evolution within an adaptive radiation of cichlid fishes.

    Science.gov (United States)

    Muschick, Moritz; Indermaur, Adrian; Salzburger, Walter

    2012-12-18

    The recurrent evolution of convergent forms is a widespread phenomenon in adaptive radiations (e.g., [1-9]). For example, similar ecotypes of anoles lizards have evolved on different islands of the Caribbean, benthic-limnetic species pairs of stickleback fish emerged repeatedly in postglacial lakes, equivalent sets of spider ecomorphs have arisen on Hawaiian islands, and a whole set of convergent species pairs of cichlid fishes evolved in East African Lakes Malawi and Tanganyika. In all these cases, convergent phenotypes originated in geographic isolation from each other. Recent theoretical models, however, predict that convergence should be common within species-rich communities, such as species assemblages resulting from adaptive radiations. Here, we present the most extensive quantitative analysis to date of an adaptive radiation of cichlid fishes, discovering multiple instances of convergence in body and trophic morphology. Moreover, we show that convergent morphologies are associated with adaptations to specific habitats and resources and that Lake Tanganyika's cichlid communities are characterized by the sympatric occurrence of convergent forms. This prevalent coexistence of distantly related yet ecomorphologically similar species offers an explanation for the greatly elevated species numbers in cichlid species flocks. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Adaptive evolution in ecological communities.

    Directory of Open Access Journals (Sweden)

    Martin M Turcotte

    Full Text Available Understanding how natural selection drives evolution is a key challenge in evolutionary biology. Most studies of adaptation focus on how a single environmental factor, such as increased temperature, affects evolution within a single species. The biological relevance of these experiments is limited because nature is infinitely more complex. Most species are embedded within communities containing many species that interact with one another and the physical environment. To understand the evolutionary significance of such ecological complexity, experiments must test the evolutionary impact of interactions among multiple species during adaptation. Here we highlight an experiment that manipulates species composition and tracks evolutionary responses within each species, while testing for the mechanisms by which species interact and adapt to their environment. We also discuss limitations of previous studies of adaptive evolution and emphasize how an experimental evolution approach can circumvent such shortcomings. Understanding how community composition acts as a selective force will improve our ability to predict how species adapt to natural and human-induced environmental change.

  11. Adaptive evolution in ecological communities.

    Science.gov (United States)

    Turcotte, Martin M; Corrin, Michael S C; Johnson, Marc T J

    2012-01-01

    Understanding how natural selection drives evolution is a key challenge in evolutionary biology. Most studies of adaptation focus on how a single environmental factor, such as increased temperature, affects evolution within a single species. The biological relevance of these experiments is limited because nature is infinitely more complex. Most species are embedded within communities containing many species that interact with one another and the physical environment. To understand the evolutionary significance of such ecological complexity, experiments must test the evolutionary impact of interactions among multiple species during adaptation. Here we highlight an experiment that manipulates species composition and tracks evolutionary responses within each species, while testing for the mechanisms by which species interact and adapt to their environment. We also discuss limitations of previous studies of adaptive evolution and emphasize how an experimental evolution approach can circumvent such shortcomings. Understanding how community composition acts as a selective force will improve our ability to predict how species adapt to natural and human-induced environmental change.

  12. The consequences of balanced harvesting of fish communities

    DEFF Research Database (Denmark)

    Jacobsen, Nis Sand; Gislason, Henrik; Andersen, Ken Haste

    2014-01-01

    , for a given yield, the least change in the relative biomass composition of the fish community. Because fishing reduces competition, predation and cannibalism within the community, the total maximum sustainable yield is achieved at high exploitation rates. The yield from unselective balanced fishing...

  13. Perceptions about mercury and lead in fish consumed in Lake Albert fishing communities Uganda

    Science.gov (United States)

    Andrew, Tamale; Francis, Ejobi; Charles, Muyanja; Naigaga, Irene; Jesca, Nakavuma; Micheal, Ocaido; Anne, Katuhoire; Deborah, Amulen

    2016-01-01

    Abstract Fish consumption is a lifestyle in fishing communities influenced by individual and communal perceptions. However, information about individual perceptions about fish consumption in the vulnerable fishing community in a developing country is lacking. Without this study, the benefits of fish consumption in a vulnerable community may not be realized. Data collection was executed using key informant interviews and survey structured questionnaires. The key informants include fisheries, community development, veterinary, community and environmental officers. The household heads were the respondents. The Qualitative data was organized and queried using QSR Nvivo 10 and quantitative data analyzed with SPSS version 22. The perceived benefits of eating fish are health, income, nutrition and manhood. The perceived risks are Stigma and ill health. The factors increasing fish consumption are heedless of fish consumption benefits (p = 0.041) and household size i.e. number of adults more than seven (p = 0.020). Those decreasing are methods of preparation of fish i.e. boiling and frying (p = 0.019 and p = 0.010) and oblivious about organizations dealing with fishing activities (p = 0.029). An awareness campaign is needed to demystify the health benefits and fallacies of fish consumption. The knowledge on individual perceptions associated with fish consumption will increase fish consumption but with fewer risks.

  14. Offshore Fish Community: Ecological Interactions | Science ...

    Science.gov (United States)

    The offshore (>80 m) fish community of Lake Superior is made up of predominately native species. The most prominent species are deepwater sculpin, kiyi, cisco, siscowet lake trout, burbot, and the exotic sea lamprey. Bloater and shortjaw cisco are also found in the offshore zone. Bloater is abundant in the offshore zone but appears restricted to depths shallower than 150 m (Selgeby and Hoff 1996; Stockwell et al. 2010), although it occuppied greater depths several decades ago (Dryer 1966; Peck 1977). Shortjaw is relatively rare in the offshore zone (Hoff and Todd 2004; Gorman and Hoff 2009; Gorman and Todd 2007). Lake whitefish is also known to frequent bathymetric depths >100 m (Yule et al. 2008b). In this chapter, we develop a conceptual model of the offshore food web based on data collected during 2001-2005 and on inferences from species interactions known for the nearshore fish community. We then develop a framework for examination of energy and nutrient movements within the pelagic and benthic habitats of the offshore zone and across the offshore and nearshore zones. To document research results.

  15. Tropical fishes dominate temperate reef fish communities within western Japan.

    Science.gov (United States)

    Nakamura, Yohei; Feary, David A; Kanda, Masaru; Yamaoka, Kosaku

    2013-01-01

    Climate change is resulting in rapid poleward shifts in the geographical distribution of tropical and subtropical fish species. We can expect that such range shifts are likely to be limited by species-specific resource requirements, with temperate rocky reefs potentially lacking a range of settlement substrates or specific dietary components important in structuring the settlement and success of tropical and subtropical fish species. We examined the importance of resource use in structuring the distribution patterns of range shifting tropical and subtropical fishes, comparing this with resident temperate fish species within western Japan (Tosa Bay); the abundance, diversity, size class, functional structure and latitudinal range of reef fishes utilizing both coral reef and adjacent rocky reef habitat were quantified over a 2 year period (2008-2010). This region has undergone rapid poleward expansion of reef-building corals in response to increasing coastal water temperatures, and forms one of the global hotspots for rapid coastal changes. Despite the temperate latitude surveyed (33°N, 133°E) the fish assemblage was both numerically, and in terms of richness, dominated by tropical fishes. Such tropical faunal dominance was apparent within both coral, and rocky reef habitats. The size structure of the assemblage suggested that a relatively large number of tropical species are overwintering within both coral and rocky habitats, with a subset of these species being potentially reproductively active. The relatively high abundance and richness of tropical species with obligate associations with live coral resources (i.e., obligate corallivores) shows that this region holds the most well developed temperate-located tropical fish fauna globally. We argue that future tropicalisation of the fish fauna in western Japan, associated with increasing coral habitat development and reported increasing shifts in coastal water temperatures, may have considerable positive economic

  16. Tropical fishes dominate temperate reef fish communities within western Japan.

    Directory of Open Access Journals (Sweden)

    Yohei Nakamura

    Full Text Available Climate change is resulting in rapid poleward shifts in the geographical distribution of tropical and subtropical fish species. We can expect that such range shifts are likely to be limited by species-specific resource requirements, with temperate rocky reefs potentially lacking a range of settlement substrates or specific dietary components important in structuring the settlement and success of tropical and subtropical fish species. We examined the importance of resource use in structuring the distribution patterns of range shifting tropical and subtropical fishes, comparing this with resident temperate fish species within western Japan (Tosa Bay; the abundance, diversity, size class, functional structure and latitudinal range of reef fishes utilizing both coral reef and adjacent rocky reef habitat were quantified over a 2 year period (2008-2010. This region has undergone rapid poleward expansion of reef-building corals in response to increasing coastal water temperatures, and forms one of the global hotspots for rapid coastal changes. Despite the temperate latitude surveyed (33°N, 133°E the fish assemblage was both numerically, and in terms of richness, dominated by tropical fishes. Such tropical faunal dominance was apparent within both coral, and rocky reef habitats. The size structure of the assemblage suggested that a relatively large number of tropical species are overwintering within both coral and rocky habitats, with a subset of these species being potentially reproductively active. The relatively high abundance and richness of tropical species with obligate associations with live coral resources (i.e., obligate corallivores shows that this region holds the most well developed temperate-located tropical fish fauna globally. We argue that future tropicalisation of the fish fauna in western Japan, associated with increasing coral habitat development and reported increasing shifts in coastal water temperatures, may have considerable

  17. Evaluating analytical approaches for estimating pelagic fish biomass using simulated fish communities

    Science.gov (United States)

    Yule, Daniel L.; Adams, Jean V.; Warner, David M.; Hrabik, Thomas R.; Kocovsky, Patrick M.; Weidel, Brian C.; Rudstam, Lars G.; Sullivan, Patrick J.

    2013-01-01

    Pelagic fish assessments often combine large amounts of acoustic-based fish density data and limited midwater trawl information to estimate species-specific biomass density. We compared the accuracy of five apportionment methods for estimating pelagic fish biomass density using simulated communities with known fish numbers that mimic Lakes Superior, Michigan, and Ontario, representing a range of fish community complexities. Across all apportionment methods, the error in the estimated biomass generally declined with increasing effort, but methods that accounted for community composition changes with water column depth performed best. Correlations between trawl catch and the true species composition were highest when more fish were caught, highlighting the benefits of targeted trawling in locations of high fish density. Pelagic fish surveys should incorporate geographic and water column depth stratification in the survey design, use apportionment methods that account for species-specific depth differences, target midwater trawling effort in areas of high fish density, and include at least 15 midwater trawls. With relatively basic biological information, simulations of fish communities and sampling programs can optimize effort allocation and reduce error in biomass estimates.

  18. Change in fish community structure in the Barents Sea.

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    Michaela Aschan

    Full Text Available Change in oceanographic conditions causes structural alterations in marine fish communities, but this effect may go undetected as most monitoring programs until recently mainly have focused on oceanography and commercial species rather than on whole ecosystems. In this paper, the objective is to describe the spatial and temporal changes in the Barents Sea fish community in the period 1992-2004 while taking into consideration the observed abundance and biodiversity patterns for all 82 observed fish species. We found that the spatial structure of the Barents Sea fish community was determined by abiotic factors such as temperature and depth. The observed species clustered into a deep assemblage, a warm water southern assemblage, both associated with Atlantic water, and a cold water north-eastern assemblage associated with mixed water. The latitude of the cold water NE and warm water S assemblages varied from year to year, but no obvious northward migration was observed over time. In the period 1996-1999 we observed a significant reduction in total fish biomass, abundance, mean fish weight, and a change in community structure including an increase in the pelagic/demersal ratio. This change in community structure is probably due to extremely cold conditions in 1996 impacting on a fish community exposed to historically high fishing rates. After 1999 the fish community variables such as biomass, abundance, mean weight, P/D ratio as well as community composition did not return to levels of the early 90s, although fishing pressure and climatic conditions returned to earlier levels.

  19. Atlantic reef fish biogeography and evolution

    Science.gov (United States)

    Floeter, S.R.; Rocha, L.A.; Robertson, D.R.; Joyeux, J.C.; Smith-Vaniz, W.F.; Wirtz, P.; Edwards, A.J.; Barreiros, J.P.; Ferreira, C.E.L.; Gasparini, J.L.; Brito, A.; Falcon, J.M.; Bowen, B.W.; Bernardi, G.

    2008-01-01

    Aim: To understand why and when areas of endemism (provinces) of the tropical Atlantic Ocean were formed, how they relate to each other, and what processes have contributed to faunal enrichment. Location: Atlantic Ocean. Methods: The distributions of 2605 species of reef fishes were compiled for 25 areas of the Atlantic and southern Africa. Maximum-parsimony and distance analyses were employed to investigate biogeographical relationships among those areas. A collection of 26 phylogenies of various Atlantic reef fish taxa was used to assess patterns of origin and diversification relative to evolutionary scenarios based on spatio-temporal sequences of species splitting produced by geological and palaeoceanographic events. We present data on faunal (species and genera) richness, endemism patterns, diversity buildup (i.e. speciation processes), and evaluate the operation of the main biogeographical barriers and/or filters. Results: Phylogenetic (proportion of sister species) and distributional (number of shared species) patterns are generally concordant with recognized biogeographical provinces in the Atlantic. The highly uneven distribution of species in certain genera appears to be related to their origin, with highest species richness in areas with the greatest phylogenetic depth. Diversity buildup in Atlantic reef fishes involved (1) diversification within each province, (2) isolation as a result of biogeographical barriers, and (3) stochastic accretion by means of dispersal between provinces. The timing of divergence events is not concordant among taxonomic groups. The three soft (non-terrestrial) inter-regional barriers (mid-Atlantic, Amazon, and Benguela) clearly act as 'filters' by restricting dispersal but at the same time allowing occasional crossings that apparently lead to the establishment of new populations and species. Fluctuations in the effectiveness of the filters, combined with ecological differences among provinces, apparently provide a mechanism

  20. Evolution of the fish rhabdovirus viral haemorrhagic septicaemia virus

    DEFF Research Database (Denmark)

    Einer-Jensen, Katja; Ahrens, Peter; Forsberg, Roald

    2004-01-01

    of free-living marine fish species. To study the genetic evolution of VHSV, the entire G gene from 74 isolates was analysed. VHSV from wild marine species caught in the Baltic Sea, Skagerrak, Kattegat, North Sea, and English Channel and European freshwater isolates, appeared to share a recent common...

  1. The Evolution of Learning Communities: A Retrospective

    Science.gov (United States)

    Matthews, Roberta S.; Smith, Barbara Leigh; MacGregor, Jean

    2012-01-01

    This volume focuses on learning communities at the beginning and at the culmination of work in the major of psychology and reflects a commitment to good practice both within and outside the classroom. Its comprehensive approach attests to the power of learning communities within the discipline and is a fine example of their evolution. In this…

  2. Baseline assessment of fish communities of the Flower Garden Banks

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The work developed baseline information on fish and benthic communities within the Flower Garden Banks National Marine Sanctuary (FGBNMS). Surveys employed diving,...

  3. Changes in the North Sea fish community: evidence of indirect effects of fishing?

    DEFF Research Database (Denmark)

    Daan, N.; Gislason, Henrik; Pope, J.;

    2005-01-01

    We investigate changes in the North Sea fish community with particular reference to possible indirect effects of fishing, mediated through the ecosystem. In the past, long-term changes in the slope of size spectra of research vessel catches have been related to changes in fishing effort, but such...... were obtained only if time lags greater than or equal to 6 years were introduced. (C) 2004 International Council for the Exploration of the Sea. Published by Elsevier Ltd. All rights reserved....

  4. Biodiversity and adaptive evolution of Antarctic notothenioid fishes

    Directory of Open Access Journals (Sweden)

    Qianghua Xu

    2014-01-01

    Full Text Available The sea surrounding the Antarctic continent is one of the coldest regions in the world. It provides an environmentally unique and isolated “hotbed” for evolution to take place. In the past 30 million years, species of Perciform suborder Notothenioidei evolved and diversified from a benthic and temperate-water ancestor, and now dominate the fish fauna of the coldest ocean. Because of their distribution across temperature zones both inside and outside the Antarctic Polar Front, notothenioid fishes are regarded as excellent model organisms for exploring mechanisms of adaptive evolution, particularly cold adaptation. We first summarize research progress on the biodiversity of Antarctic fish and then review current findings on the peculiar biological characteristics of Antarctic notothenioids that evolved in response to a freezing environment. Research has revealed that extensive gene duplication and transcriptomic changes occurred during the adaptive radiation of notothenioid fish. Examples of highly duplicated genes in the Antarctic lineages include genes encoding hepcidin, and zona pellucida proteins, in addition to various retrotransposable elements. A few genes from Antarctic notothenioid fishes have been used as transgenes and demonstrated to be effective in making transgenic plants cold-hardy. In the coming years, the genomes of some Antarctic notothenioid species will be fully sequenced and the adaptive functions of duplicated genes will be further elucidated. Such studies will deepen our understanding of how genomes evolve in freezing environments, and provide an improved knowledge of molecular mechanisms of cold adaptation.

  5. Preliminary assessment of factors influencing riverine fish communities in Massachusetts.

    Science.gov (United States)

    Armstrong, David S.; Richards, Todd A.; Brandt, Sara L.

    2010-01-01

    The U.S. Geological Survey, in cooperation with the Massachusetts Department of Conservation and Recreation (MDCR), Massachusetts Department of Environmental Protection (MDEP), and the Massachusetts Department of Fish and Game (MDFG), conducted a preliminary investigation of fish communities in small- to medium-sized Massachusetts streams. The objective of this investigation was to determine relations between fish-community characteristics and anthropogenic alteration, including flow alteration and impervious cover, relative to the effect of physical basin and land-cover (environmental) characteristics. Fish data were obtained for 756 fish-sampling sites from the Massachusetts Division of Fisheries and Wildlife fish-community database. A review of the literature was used to select a set of fish metrics responsive to flow alteration. Fish metrics tested include two fish-community metrics (fluvial-fish relative abundance and fluvial-fish species richness), and five indicator species metrics (relative abundance of brook trout, blacknose dace, fallfish, white sucker, and redfin pickerel). Streamflows were simulated for each fish-sampling site using the Sustainable Yield Estimator application (SYE). Daily streamflows and the SYE water-use database were used to determine a set of indicators of flow alteration, including percent alteration of August median flow, water-use intensity, and withdrawal and return-flow fraction. The contributing areas to the fish-sampling sites were delineated and used with a Geographic Information System (GIS) to determine a set of environmental characteristics, including elevation, basin slope, percent sand and gravel, percent wetland, and percent open water, and a set of anthropogenic-alteration variables, including impervious cover and dam density. Two analytical techniques, quantile regression and generalized linear modeling, were applied to determine the association between fish-response variables and the selected environmental and

  6. Community rallies to save imperiled fish

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    US Fish and Wildlife Service, Department of the Interior — Newspaper article highlighting a plan for future construction of the Seven Springs Ecoscape, a park designed to protect the endangered watercress darter and educate...

  7. Structure and function of fish communities in the southern Lake Michigan basin with emphasis on restoration of native fish communities

    Science.gov (United States)

    Simon, Thomas P.; Stewart, Paul M.

    1999-01-01

    The southern Lake Michigan basin in northwest Indiana possesses a variety of aquatic habitats including riverine, palustrine, and lacustrine systems. The watershed draining this area is a remnant of glacial Lake Chicago and supports fish communities that are typically low in species richness. Composition of the presettlement Lake Michigan fish community near the Indiana Dunes has been difficult to reconstruct. Existing data indicate that the number of native species in the Lake Michigan watershed, including nearshore Lake Michigan, has declined by 22% since the onset of European settlement. Few remnants of natural fish communities exist, and those occur principally in the ponds of Miller Woods, the Grand Calumet Lagoons, and the Little Calumet River. These communities have maintained a relatively diverse assemblage of fishes despite large-scale anthropogenic disturbances in the area, including channelization, massive river redirection, fragmentation, habitat alteration, exotic species invasions, and the introduction of toxic chemicals. Data that we collected from 1985 to 1996 suggested that the Grand Calumet River has the highest proportion of exotic fish species of any inland wetland in northwest Indiana. Along the Lake Michigan shoreline, another group of exotics (e.g., round goby, alewife, and sea lamprey) have affected the structure of native fish communities, thereby altering lake ecosystem function. Stocking programs contribute to the impairment of native communities. Nonindigenous species have restructured the function of Lake Michigan tributaries, causing disruptions in trophic dynamics, guild structure, and species diversity. Several fish communities have been reduced or eliminated by the alteration and destruction of spawning and nursery areas. Degradation of habitats has caused an increase in numbers and populations of species able to tolerate and flourish when confronted with hydrologic alteration. Fish communities found on public lands in northwest

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

    Science.gov (United States)

    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.

  9. Long-term effects of the cleaner fish Labroides dimidiatus on coral reef fish communities.

    Directory of Open Access Journals (Sweden)

    Peter A Waldie

    Full Text Available Cleaning behaviour is deemed a mutualism, however the benefit of cleaning interactions to client individuals is unknown. Furthermore, mechanisms that may shift fish community structure in the presence of cleaning organisms are unclear. Here we show that on patch reefs (61-285 m² which had all cleaner wrasse Labroides dimidiatus (Labridae experimentally removed (1-5 adults reef⁻¹ and which were then maintained cleaner-fish free over 8.5 years, individuals of two site-attached (resident client damselfishes (Pomacentridae were smaller compared to those on control reefs. Furthermore, resident fishes were 37% less abundant and 23% less species rich per reef, compared to control reefs. Such changes in site-attached fish may reflect lower fish growth rates and/or survivorship. Additionally, juveniles of visitors (fish likely to move between reefs were 65% less abundant on removal reefs suggesting cleaners may also affect recruitment. This may, in part, explain the 23% lower abundance and 33% lower species richness of visitor fishes, and 66% lower abundance of visitor herbivores (Acanthuridae on removal reefs that we also observed. This is the first study to demonstrate a benefit of cleaning behaviour to client individuals, in the form of increased size, and to elucidate potential mechanisms leading to community-wide effects on the fish population. Many of the fish groups affected may also indirectly affect other reef organisms, thus further impacting the reef community. The large-scale effect of the presence of the relatively small and uncommon fish, Labroides dimidiadus, on other fishes is unparalleled on coral reefs.

  10. Molecular evolution of communication signals in electric fish.

    Science.gov (United States)

    Zakon, Harold H; Zwickl, Derrick J; Lu, Ying; Hillis, David M

    2008-06-01

    Animal communication systems are subject to natural selection so the imprint of selection must reside in the genome of each species. Electric fish generate electric organ discharges (EODs) from a muscle-derived electric organ (EO) and use these fields for electrolocation and communication. Weakly electric teleosts have evolved at least twice (mormyriforms, gymnotiforms) allowing a comparison of the workings of evolution in two independently evolved sensory/motor systems. We focused on the genes for two Na(+) channels, Nav1.4a and Nav1.4b, which are orthologs of the mammalian muscle-expressed Na(+) channel gene Nav1.4. Both genes are expressed in muscle in non-electric fish. Nav1.4b is expressed in muscle in electric fish, but Nav1.4a expression has been lost from muscle and gained in the evolutionarily novel EO in both groups. We hypothesized that Nav1.4a might be evolving to optimize the EOD for different sensory environments and the generation of species-specific communication signals. We obtained the sequence for Nav1.4a from non-electric, mormyriform and gymnotiform species, estimated a phylogenetic tree, and determined rates of evolution. We observed elevated rates of evolution in this gene in both groups coincident with the loss of Nav1.4a from muscle and its compartmentalization in EO. We found amino acid substitutions at sites known to be critical for channel inactivation; analyses suggest that these changes are likely to be the result of positive selection. We suggest that the diversity of EOD waveforms in both groups of electric fish is correlated with accelerations in the rate of evolution of the Nav1.4a Na(+) channel gene due to changes in selection pressure on the gene once it was solely expressed in the EO.

  11. The role of the nervous system in fish evolution

    Directory of Open Access Journals (Sweden)

    Michael H Hofmann

    2015-12-01

    Full Text Available The nervous system plays an important role in the evolution and adaptation of animals. All sensory and motor functions as well as cognitive abilities are organized in the brain and spinal cord. Volumetric measurements of different brain regions were made in more than 150 species of ray finned fishes as well as in several outgroups. In Actanthopterygii, the hypothalamus shows greatest enlargement most likely due to an enormous visual input via the nucleus glomerulosos. The telencephalon is highly differentiated in many acanthopterygii, mostly coral reef species, but its relative size is not much effected. There is, however, a clear shift from olfactory to visual functions in ray finned fishes. In species with a highly differentiated telencephalon, the area where place memory may be located is very prominent. In basal ray finned fishes, lungfish, amphibia and elasmobranchs, the olfactory bulb is relatively large and the ratio of the olfactory bulb and telencephalon large as well. This holds also for elopomorpha and spiny eels, but in most other groups vision dominates. Apart from differences between larger clades, variation in brain architecture are also seen in closely related species and even between sexes of the same species. Profound differences are present in the cerebellum between male and female swordtails and in the telencephalon of sticklebacks. Morphometric analysis of brain architecture turned out to be an important tool to study the evolution and adaptations of the brain in fishes.

  12. Fish-derived nutrient hotspots shape coral reef benthic communities.

    Science.gov (United States)

    Shantz, Andrew A; Ladd, Mark C; Schrack, Elizabeth; Burkepile, Deron E

    2015-12-01

    Animal-derived nutrients play an important role in structuring nutrient regimes within and between ecosystems. When animals undergo repetitive, aggregating behavior through time, they can create nutrient hotspots where rates of biogeochemical activity are higher than those found in the surrounding environment. In turn, these hotspots can influence ecosystem processes and community structure. We examined the potential for reef fishes from the family Haemulidae (grunts) to create nutrient hotspots and the potential impact of these hotspots on reef communities. To do so, we tracked the schooling locations of diurnally migrating grunts, which shelter at reef sites during the day but forage off reef each night, and measured the impact of these fish schools on benthic communities. We found that grunt schools showed a high degree of site fidelity, repeatedly returning to the same coral heads. These aggregations created nutrient hotspots around coral heads where nitrogen and phosphorus delivery was roughly 10 and 7 times the respective rates of delivery to structurally similar sites that lacked schools of these fishes. In turn, grazing rates of herbivorous fishes at grunt-derived hotspots were approximately 3 times those of sites where grunts were rare. These differences in nutrient delivery and grazing led to distinct benthic communities with higher cover of crustose coralline algae and less total algal abundance at grunt aggregation sites. Importantly, coral growth was roughly 1.5 times greater at grunt hotspots, likely due to the important nutrient subsidy. Our results suggest that schooling reef fish and their nutrient subsidies play an important role in mediating community structure on coral reefs and that overfishing may have important negative consequences on ecosystem functions. As such, management strategies must consider mesopredatory fishes in addition to current protection often offered to herbivores and top-tier predators. Furthermore, our results suggest that

  13. Native fish conservation areas: A vision for large-scale conservation of native fish communities

    Science.gov (United States)

    Williams, Jack E.; Williams, Richard N.; Thurow, Russell F.; Elwell, Leah; Philipp, David P.; Harris, Fred A.; Kershner, Jeffrey L.; Martinez, Patrick J.; Miller, Dirk; Reeves, Gordon H.; Frissell, Christopher A.; Sedell, James R.

    2011-01-01

    The status of freshwater fishes continues to decline despite substantial conservation efforts to reverse this trend and recover threatened and endangered aquatic species. Lack of success is partially due to working at smaller spatial scales and focusing on habitats and species that are already degraded. Protecting entire watersheds and aquatic communities, which we term "native fish conservation areas" (NFCAs), would complement existing conservation efforts by protecting intact aquatic communities while allowing compatible uses. Four critical elements need to be met within a NFCA: (1) maintain processes that create habitat complexity, diversity, and connectivity; (2) nurture all of the life history stages of the fishes being protected; (3) include a long-term enough watershed to provide long-term persistence of native fish populations; and (4) provide management that is sustainable over time. We describe how a network of protected watersheds could be created that would anchor aquatic conservation needs in river basins across the country.

  14. Impact of fishing on size composition and diversity of demersal fish communities

    DEFF Research Database (Denmark)

    Bianchi, G.; Gislason, Henrik; Graham, K.;

    2000-01-01

    . but particularly in high-latitude regions, we observe a decreasing trend in the slope, reflecting changes in size composition toward a relative decline in larger fish. The results from tropical regions are less conclusive, partly owing to the difficulty in obtaining consistent data series, but probably also......By analysing data sets from different world regions we add evidence to documented changes in demersal fish community structure that may be related to fishing. Changes are analysed by community properties that might be expected to capture relevant overall changes - size spectra slopes and intercepts...... because the generally higher growth rates of the constituent species make the slope less sensitive to changes in fishing. No evidence was found of any decline in species richness, while changes in diversity (richness and evenness) were caused either by changes in patterns of dominance or by changes...

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

    Science.gov (United States)

    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

  16. Olfactory receptor gene family evolution in stickleback and medaka fishes

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Interaction of olfactory receptor (OR) genes with environmental odors is regarded as the first step of olfaction.In this study,OR genes of two fish,medaka (Oryzias latipes) and stickleback (Gasterosteus aculeatus),were identified and an evolutional analysis was conducted.The selection pressure of different TM regions and complete coding region were compared.Three TM regions (TM4,TM5 and TM6) were found to have higher average Ka/Ks values,which might be partly caused by positive selection as suggested by subsequent positive selection analysis.Further analysis showed that many PTSs overlap,or are adjacent to previously deduced binding sites in mammals.These results support the hypothesis that binding sites of fish OR genes may evolved under positive selection.

  17. Predicting Community Evolution in Social Networks

    Directory of Open Access Journals (Sweden)

    Stanisław Saganowski

    2015-05-01

    Full Text Available Nowadays, sustained development of different social media can be observed worldwide. One of the relevant research domains intensively explored recently is analysis of social communities existing in social media as well as prediction of their future evolution taking into account collected historical evolution chains. These evolution chains proposed in the paper contain group states in the previous time frames and its historical transitions that were identified using one out of two methods: Stable Group Changes Identification (SGCI and Group Evolution Discovery (GED. Based on the observed evolution chains of various length, structural network features are extracted, validated and selected as well as used to learn classification models. The experimental studies were performed on three real datasets with different profile: DBLP, Facebook and Polish blogosphere. The process of group prediction was analysed with respect to different classifiers as well as various descriptive feature sets extracted from evolution chains of different length. The results revealed that, in general, the longer evolution chains the better predictive abilities of the classification models. However, chains of length 3 to 7 enabled the GED-based method to almost reach its maximum possible prediction quality. For SGCI, this value was at the level of 3–5 last periods.

  18. The response of the North Sea demersal fish community to changing fishing pressure as seen through the prism of the large fish indicator

    NARCIS (Netherlands)

    Stamoulis, Antonios; Torreele, Els

    2016-01-01

    The large fish indicator (LFI) is a size-based indicator of fish community state. In the North Sea, the LFI is already established as the fish community's Ecological Quality Objective (OSPAR-EcoQO). The LFI has also been proposed as an indicator for food webs and for monitoring of biodiversity in

  19. Reef fish communities in the central Red Sea show evidence of asymmetrical fishing pressure

    KAUST Repository

    Kattan, Alexander

    2017-03-09

    In order to assess human impacts and develop rational restoration goals for corals reefs, baseline estimates of fish communities are required. In Saudi Arabian waters of the Red Sea, widespread unregulated fishing is thought to have been ongoing for decades, but there is little direct evidence of the impact on reef communities. To contextualize this human influence, reef-associated fish assemblages on offshore reefs in Saudi Arabia and Sudan in the central Red Sea were investigated. These reefs have comparable benthic environments, experience similar oceanographic influences, and are separated by less than 300 km, offering an ideal comparison for identifying potential anthropogenic impacts such as fishing pressure. This is the first study to assess reef fish biomass in both these regions, providing important baselines estimates. We found that biomass of top predators on offshore Sudanese reefs was on average almost three times that measured on comparable reefs in Saudi Arabia. Biomass values from some of the most remote reefs surveyed in Sudan’s far southern region even approach those previously reported in the Northwestern Hawaiian Islands, northern Line Islands, Pitcairn Islands, and other isolated Pacific islands and atolls. The findings suggest that fishing pressure has significantly altered the fish community structure of Saudi Arabian Red Sea reefs, most conspicuously in the form of top predator removal. The results point towards the urgent need for enhanced regulation and enforcement of fishing practices in Saudi Arabia, while making a strong case for protection in the form of no-take marine protected areas to maintain preservation of the relatively intact southern Sudanese Red Sea.

  20. Ecology of the Lake Huron fish community, 1970-1999

    Science.gov (United States)

    Dobiesz, Norine E.; McLeish, David A.; Eshenroder, Randy L.; Bence, James R.; Mohr, Lloyd C.; Ebener, Mark P.; Nalepa, Thomas F.; Woldt, Aaron P.; Johnson, James E.; Argyle, Ray L.; Makarewicz, Joseph C.

    2005-01-01

    We review the status of the Lake Huron fish community between 1970 and 1999 and explore the effects of key stressors. Offshore waters changed little in terms of nutrient enrichment, while phosphorus levels declined in inner Saginaw Bay. Introduced mussels (Dreissena spp.) proliferated and may have caused a decline in Diporeia spp. This introduction could have caused a decline in lake whitefish (Coregonus clupeaformis) growth and condition, with serious repercussions for commercial fisheries. Bythotrephes, an exotic predatory cladoceran, and other new exotics may be influencing the fish community. Sea lampreys (Petromyzon marinus) remained prevalent, but intensive control efforts on the St. Mary's River may reduce their predation on salmonines. Overfishing was less of a problem than in the past, although fishing continued to reduce the amount of lake trout (Salvelinus namaycush) spawning biomass resulting from hatchery-reared fish planted to rehabilitate this species. Massive stocking programs have increased the abundance of top predators, but lake trout were rehabilitated in only one area. Successful lake trout rehabilitation may require lower densities of introduced pelagic prey fish than were seen in the 1990s, along with continued stocking of hatchery-reared lake trout and control of sea lamprey. Such reductions in prey fish could limit Pacific salmon (Oncorhynchus spp.) fisheries.

  1. Fish community change in Lake Superior, 1970-2000

    Science.gov (United States)

    Bronte, Charles R.; Ebener, Mark P.; Schreiner, Donald R.; DeVault, David S.; Petzold, Michael M.; Jensen, Douglas A.; Richards, Carl; Lozano, Steven J.

    2003-01-01

    Changes in Lake Superior's fish community are reviewed from 1970 to 2000. Lake trout (Salvelinus namaycush) and lake whitefish (Coregonus clupeaformis) stocks have increased substantially and may be approaching ancestral states. Lake herring (Coregonus artedi) have also recovered, but under sporadic recruitment. Contaminant levels have declined and are in equilibrium with inputs, but toxaphene levels are higher than in all other Great Lakes. Sea lamprey (Petromyzon marinus) control, harvest limits, and stocking fostered recoveries of lake trout and allowed establishment of small nonnative salmonine populations. Natural reproduction supports most salmonine populations, therefore further stocking is not required. Nonnative salmonines will likely remain minor components of the fish community. Forage biomass has shifted from exotic rainbow smelt (Osmerus mordax) to native species, and high predation may prevent their recovery. Introductions of exotics have increased and threaten the recovering fish community. Agencies have little influence on the abundance of forage fish or the major predator, siscowet lake trout, and must now focus on habitat protection and enhancement in nearshore areas and prevent additional species introductions to further restoration. Persistence of Lake Superior's native deepwater species is in contrast to other Great Lakes where restoration will be difficult in the absence of these ecologically important fishes.

  2. CHARACTERISTICS OFBENTHIC FISH COMMUNITY OF DNIEPER STORAGE POOL LITTORAL ZONE

    Directory of Open Access Journals (Sweden)

    Novitskiy R. A.

    2011-11-01

    Full Text Available Specific composition of bull-calves is analyzed together with their quantitative and quality parameters in the littoral zone of the Dnepr storage pool. The structural-functional features of organization of littoral communities of bull-calves were studied. The patterns of spatial distribution of Bull-calf (Gobiidae representatives were analyzed for the storage pool; their role in the littoral fish communities was clarified.

  3. Food-web patterns and diversity in tropical fish communities

    NARCIS (Netherlands)

    Amarasinghe, U.S.; Vijverberg, J.; Weliange, W.S.; Vos, M.

    2014-01-01

    The food webs for three Sri Lankan reservoirs, Minneriya (ancient and shallow), Udawalawe (young and shallow) and Victoria (young and deep), were compared. The species richness of the fish communities was highest in Minneriya (30 species), intermediate in Udawalawe (21 species) and lowest in Victori

  4. Food-web patterns and diversity in tropical fish communities

    NARCIS (Netherlands)

    Amarasinghe, U.S.; Vijverberg, J.; Weliange, W.S.; Vos, M.

    2014-01-01

    The food webs for three Sri Lankan reservoirs, Minneriya (ancient and shallow), Udawalawe (young and shallow) and Victoria (young and deep), were compared. The species richness of the fish communities was highest in Minneriya (30 species), intermediate in Udawalawe (21 species) and lowest in

  5. Does functional redundancy stabilize fish communities?

    DEFF Research Database (Denmark)

    Rice, Jake; Daan, Niels; Gislason, Henrik;

    2012-01-01

    time‐series of data on 83 species sampled in the International Bottom Trawl Survey. Our results were consistent with the hypothesis that functional redundancy leads to more stable (and by inference more resilient) communities. Over the time‐series trophic groups (assigned by diet, size (Lmax) group...

  6. Transposable elements and early evolution of sex chromosomes in fish.

    Science.gov (United States)

    Chalopin, Domitille; Volff, Jean-Nicolas; Galiana, Delphine; Anderson, Jennifer L; Schartl, Manfred

    2015-09-01

    In many organisms, the sex chromosome pair can be recognized due to heteromorphy; the Y and W chromosomes have often lost many genes due to the absence of recombination during meiosis and are frequently heterochromatic. Repetitive sequences are found at a high proportion on such heterochromatic sex chromosomes and the evolution and emergence of sex chromosomes has been connected to the dynamics of repeats and transposable elements. With an amazing plasticity of sex determination mechanisms and numerous instances of independent emergence of novel sex chromosomes, fish represent an excellent lineage to investigate the early stages of sex chromosome differentiation, where sex chromosomes often are homomorphic and not heterochromatic. We have analyzed the composition, distribution, and relative age of TEs from available sex chromosome sequences of seven teleost fish. We observed recent bursts of TEs and simple repeat accumulations around young sex determination loci. More strikingly, we detected transposable element (TE) amplifications not only on the sex determination regions of the Y and W sex chromosomes, but also on the corresponding regions of the X and Z chromosomes. In one species, we also clearly demonstrated that the observed TE-rich sex determination locus originated from a TE-poor genomic region, strengthening the link between TE accumulation and emergence of the sex determination locus. Altogether, our results highlight the role of TEs in the initial steps of differentiation and evolution of sex chromosomes.

  7. Community structure and seasonal variation of an inshore demersal fish community at Goa, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Ansari, Z.A.; Chatterji, A.; Ingole, B.S.; Sreepada, R.A.; Rivonker, C.U.; Parulekar, A.H.

    ) have also reported changes in composition of dominant groups due to high mechanized fishing pressure in the Gulf of Thailand. A similar trend was reported for the Terenggane coast of Malaysia, where Leiognathidae decreased significantly following heavy... temperate demersal fish community. In other fish communities, the abundant species are usually low in the tropical structure (Allen & Horn, 1975). The size of the dominant fish in a community is partially controlled by the size of the food organisms. Smaller...

  8. PCDD and PCDF exposures among fishing community through intake of fish and shellfish from the Straits of Malacca

    OpenAIRE

    Azlan, Azrina; Mohamad Nasir, Nurul Nadiah; Shamsudin, Norashikin; Rahman, Hejar Abdul; Khoo, Hock Eng; Razman, Muhammad Rizal

    2015-01-01

    Background Exposure to PCDD/PCDF (dioxin and furan) through consumption of fish and shellfish is closely related to the occurrence of skin diseases, such as chloracne and hyperpigmentation. This study aimed to determine the exposure of PCDD/PCDF and its congeners in fish and shellfish obtained from different regions of the Straits of Malacca among the fishing community. Methods The risk of fish and shellfish consumption and exposure to PCDD/PCDF among fishermen living in coastal areas of the ...

  9. Evolution of posterior lateral line development in fish and amphibians.

    Science.gov (United States)

    Pichon, Fabien; Ghysen, Alain

    2004-01-01

    The lateral line is a sensory system present in fish and amphibians. It is composed of discrete sense organs, the neuromasts, arranged on the head and body in species-specific patterns. The neuromasts are deposited by migrating primordia that originate from pre- and postotic placodes and follow defined pathways on the head and body. Here we examine the formation of the posterior lateral line (PLL), which extends rostrocaudally on the trunk and tail. In amphibians, the PLL neuromasts are deposited as a single wave from the head to the tip of the tail. In the zebrafish, however, the first wave of neuromast deposition forms but a rudimentary PLL, and several additional waves are needed to form the adult pattern. We show that the amphibian mode is also present in the sturgeon and therefore probably represents the primitive mode, whereas the zebrafish mode is highly conserved in several teleost species. A third mode is found in a subgroup of teleosts, the protacanthopterygians, and may represent a synapomorphy of this group. Altogether, the mode of formation of the embryonic PLL appears to have undergone remarkably few changes during the long history of anamniote evolution, even though large differences can be observed in the lateral line morphology of adult fishes.

  10. Social network analysis community detection and evolution

    CERN Document Server

    Missaoui, Rokia

    2015-01-01

    This book is devoted to recent progress in social network analysis with a high focus on community detection and evolution. The eleven chapters cover the identification of cohesive groups, core components and key players either in static or dynamic networks of different kinds and levels of heterogeneity. Other important topics in social network analysis such as influential detection and maximization, information propagation, user behavior analysis, as well as network modeling and visualization are also presented. Many studies are validated through real social networks such as Twitter. This edit

  11. Evolution of long-toothed fishes and the changing nature of fish-benthos interactions on coral reefs.

    Science.gov (United States)

    Bellwood, David R; Hoey, Andrew S; Bellwood, Orpha; Goatley, Christopher H R

    2014-01-01

    Interactions between fishes and the benthos have shaped the development of marine ecosystems since at least the early Mesozoic. Here, using the morphology of fish teeth as an indicator of feeding abilities, we quantify changes over the last 240 million years of reef fish evolution. Fossil and extant coral reef fish assemblages reveal exceptional stasis in tooth design over time, with one notable exception, a distinct long-toothed form. Arising only in the last 40 million years, these long-toothed fishes have bypassed the invertebrate link in the food chain, feeding directly on benthic particulate material. With the appearance of elongated teeth, these specialized detritivores have moved from eating invertebrates to eating the food of invertebrates. Over evolutionary time, fishes have slid back down the food chain.

  12. Fishing top predators indirectly affects condition and reproduction in a reef-fish community.

    Science.gov (United States)

    Walsh, S M; Hamilton, S L; Ruttenberg, B I; Donovan, M K; Sandin, S A

    2012-03-01

    To examine the indirect effects of fishing on energy allocation in non-target prey species, condition and reproductive potential were measured for five representative species (two-spot red snapper Lutjanus bohar, arc-eye hawkfish Paracirrhites arcatus, blackbar devil Plectroglyphidodon dickii, bicolour chromis Chromis margaritifer and whitecheek surgeonfish Acanthurus nigricans) from three reef-fish communities with different levels of fishing and predator abundance in the northern Line Islands, central Pacific Ocean. Predator abundance differed by five to seven-fold among islands, and despite no clear differences in prey abundance, differences in prey condition and reproductive potential among islands were found. Body condition (mean body mass adjusted for length) was consistently lower at sites with higher predator abundance for three of the four prey species. Mean liver mass (adjusted for total body mass), an indicator of energy reserves, was also lower at sites with higher predator abundance for three of the prey species and the predator. Trends in reproductive potential were less clear. Mean gonad mass (adjusted for total body mass) was high where predator abundance was high for only one of the three species in which it was measured. Evidence of consistently low prey body condition and energy reserves in a diverse suite of species at reefs with high predator abundance suggests that fishing may indirectly affect non-target prey-fish populations through changes in predation and predation risk.

  13. Fishing and Fish Consumption in the Swahili Communities of East Africa, 700–1400 CE

    Directory of Open Access Journals (Sweden)

    Eréndira M. Quintana Morales

    2014-08-01

    Full Text Available Historical and archaeological records of consumption practices indicate that people living along the Swahili coast relied largely on fish for subsistence; however, little research has been done to explore how aquatic subsistence strategies varied among different settlements in the region, both spatially and chronologically. Such questions are particularly interesting, as the communities were largely urban, and relied on fish for the bulk of their protein consumption. We compared evidence of subsistence strategies and exploited fish habitats in two Swahili regions that represent different maritime landscapes. Because particular fish species generally inhabit different sections of the marine environment, the composition of these species at each site can be used to estimate the variable exploitation of these habitats. Overall, the analysed samples showed a heavy exploitation of fish found around coral reefs, but with varying proportions of other exploited habitats, such as estuary, mangrove, sandy/muddy, and outer reef zones. The general pattern indicates that samples from offshore islands have higher representations of fish from coral/rocky habitats while samples from near-shore islands show a lower reliance on coral species. Over time there is an increase at certain sites in the exploitation of oceanic and pelagic fish that coincides with the more frequent consumption of domesticated bovids. We discuss the historical and environmental implications of these variable patterns of aquatic subsistence strategies along the East African coastline, and propose that there is a close link between their ability to exploit these marine resources, their success as urban settlements, and the development of feasting rituals.

  14. Helminth communities of four commercially important fish species from Chetumal Bay, Mexico.

    Science.gov (United States)

    Aguirre-Macedo, M L; Vidal-Martínez, V M; González-Solís, D; Caballero, P I

    2007-03-01

    The relative importance of ecology and evolution as factors determining species richness and composition of the helminth communities of fish is a matter of current debate. Theoretical studies use host-parasite lists, but these do not include studies on a temporal or spatial scale. Local environmental conditions and host biological characteristics are shown to influence helminth species richness and composition in four fish species (Eugerres plumieri, Hexanematichthys assimilis, Oligoplites saurus, and Scomberomorus maculatus) in Chetumal Bay, Mexico. With the exception of H. assimilis, the helminth communities had not been previously studied and possible associations between environmental and host biological characteristics as factors determining helminth species richness and composition using redundancy analysis (RDA) are described. Thirty-four helminth species are identified, with the highest number of species (19 total (mean = 6.3 +/- 2.1)) and the lowest (9 (4.0 +/- 1.0)) occurring in H. assimilis and S. maculatus, respectively. The larval nematodes Contracaecum sp. and Pseudoterranova sp. were not only the helminth species shared by all four host species but also were the most prevalent and abundant. Statistical associations between helminth community parameters and local ecological variables such as host habitat use, feeding habits, mobility, and time of residence in coastal lagoons are identified. Phylogeny is important because it clearly separates all four host species by their specialist parasites, although specific habitat and feeding habits also significantly influence the differentiation between the four fish species.

  15. [Reef fishes community structure of Playa Mero, Parque Nacional Morrocoy, Venezuela].

    Science.gov (United States)

    Rodríguez, J; Villamizar, E

    2000-12-01

    The coral reef fish community was studied in Playa Mero, Morrocoy National Park, after the mass mortality of January, 1996 with a systematic sampling design. Transects and quadrates were used for corals, and a visual census for fishes. The coral community is highly disturbed with extensive areas of dead coral covered by algae, and low coverage and richness of coral species, gorgonians, sponges and briozooans. These factors have generated a relatively homogeneous environment with respect to the fish community, which was dominated by Scaridae and Pomacentridae that represented 75% of fish. Dominant fishes were mainly herbivorous (75.4% of all fish) apparently because of the disturbance that caused the settling of algae.

  16. Fish community responses to green tides in shallow estuarine and coastal areas

    Science.gov (United States)

    Le Luherne, E.; Réveillac, E.; Ponsero, A.; Sturbois, A.; Ballu, S.; Perdriau, M.; Le Pape, O.

    2016-06-01

    All over the world, numerous bays and estuarine systems that are known to shelter essential fish habitats are experiencing proliferations of green macroalgae known as green tides. Although the processes that enhance green tides in response to nutrient enrichment are well known, their consequences for ecological communities -especially for ichthyofauna- remain poorly studied. To estimate these consequences, this analysis focused on the two types of shallow systems that are experiencing green tides: sandy beaches and estuarine mudflats. In these two systems, macroalgae proliferation and fish community were surveyed along seasonal cycles at control and impacted sites that shared similar physico-chemical parameters and sediment structure. To analyse the consequences of green tides on the fish community, a Before-After Control-Impact approach was used. This approach reveals no difference between fish communities at the control and impacted sites before the macroalgal bloom. Then, it underlines an influence of green tides on the fish community, and this influence varies according to the composition, density and duration of the macroalgal bloom. Indeed, when intertidal systems experienced short proliferation and/or weak density, green tides did not seem to impact the fish community. However, when green macroalgae proliferated in large quantities and/or when the proliferation lasted for long periods, the fish community was significantly affected. These modifications in the fish community led to a significant decrease in fish species diversity and density until fish disappeared from impacted sites at high proliferations. Furthermore, the response of fish species to green tides differed according to their functional guilds. Negative consequences for benthic and marine juvenile fish species were beginning at low proliferations, whereas for pelagic fish species they occurred only at high proliferations. Thus, green tides significantly affect fish habitat suitability because

  17. Accounting for Incomplete Species Detection in Fish Community Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    McManamay, Ryan A [ORNL; Orth, Dr. Donald J [Virginia Polytechnic Institute and State University; Jager, Yetta [ORNL

    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

  18. The theoretical foundations for size spectrum models of fish communities

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Jacobsen, Nis Sand; Farnsworth, K.D.

    2016-01-01

    assessment of fisheries. We describe the fundamental concepts in size-based models about food encounter and the bioenergetics budget of individuals. Within the general framework three model types have emerged that differs in their degree of complexity: the food-web, the trait-based and the community model....... We demonstrate the differences between the models through examples of their response to fishing and their dynamic behavior. We review implementations of size spectrum models and describe important variations concerning the functional response, whether growth is food-dependent or fixed...

  19. When does fishing lead to more fish? Community consequences of bottom trawl fisheries in demersal food webs

    NARCIS (Netherlands)

    Denderen, van P.D.; Kooten, van T.; Rijnsdorp, A.D.

    2013-01-01

    Bottom trawls are a globally used fishing gear that physically disturb the seabed and kill non-target organisms, including those that are food for the targeted fish species. There are indications that ensuing changes to the benthic invertebrate community may increase the availability of food and pro

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

    Directory of Open Access Journals (Sweden)

    Sahir Advani

    Full Text Available 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.

  1. Molecular evolution of globin genes in Gymnotiform electric fishes: relation to hypoxia tolerance

    National Research Council Canada - National Science Library

    Tian, Ran; Losilla, Mauricio; Lu, Ying; Yang, Guang; Zakon, Harold

    2017-01-01

    .... They function principally in oxygen-binding and -delivery in various tissues and organs. Here, we investigate the molecular evolution of alpha and beta hemoglobins, myoglobin, and neuroglobin in 12 gymnotiforms compared with other teleost fish...

  2. A new freshwater biodiversity indicator based on fish community assemblages.

    Directory of Open Access Journals (Sweden)

    Joanne Clavel

    Full Text Available Biodiversity has reached a critical state. In this context, stakeholders need indicators that both provide a synthetic view of the state of biodiversity and can be used as communication tools. Using river fishes as model, we developed community indicators that aim at integrating various components of biodiversity including interactions between species and ultimately the processes influencing ecosystem functions. We developed indices at the species level based on (i the concept of specialization directly linked to the niche theory and (ii the concept of originality measuring the overall degree of differences between a species and all other species in the same clade. Five major types of originality indices, based on phylogeny, habitat-linked and diet-linked morphology, life history traits, and ecological niche were analyzed. In a second step, we tested the relationship between all biodiversity indices and land use as a proxy of human pressures. Fish communities showed no significant temporal trend for most of these indices, but both originality indices based on diet- and habitat- linked morphology showed a significant increase through time. From a spatial point of view, all indices clearly singled out Corsica Island as having higher average originality and specialization. Finally, we observed that the originality index based on niche traits might be used as an informative biodiversity indicator because we showed it is sensitive to different land use classes along a landscape artificialization gradient. Moreover, its response remained unchanged over two other land use classifications at the global scale and also at the regional scale.

  3. A new freshwater biodiversity indicator based on fish community assemblages.

    Science.gov (United States)

    Clavel, Joanne; Poulet, Nicolas; Porcher, Emmanuelle; Blanchet, Simon; Grenouillet, Gaël; Pavoine, Sandrine; Biton, Anne; Seon-Massin, Nirmala; Argillier, Christine; Daufresne, Martin; Teillac-Deschamps, Pauline; Julliard, Romain

    2013-01-01

    Biodiversity has reached a critical state. In this context, stakeholders need indicators that both provide a synthetic view of the state of biodiversity and can be used as communication tools. Using river fishes as model, we developed community indicators that aim at integrating various components of biodiversity including interactions between species and ultimately the processes influencing ecosystem functions. We developed indices at the species level based on (i) the concept of specialization directly linked to the niche theory and (ii) the concept of originality measuring the overall degree of differences between a species and all other species in the same clade. Five major types of originality indices, based on phylogeny, habitat-linked and diet-linked morphology, life history traits, and ecological niche were analyzed. In a second step, we tested the relationship between all biodiversity indices and land use as a proxy of human pressures. Fish communities showed no significant temporal trend for most of these indices, but both originality indices based on diet- and habitat- linked morphology showed a significant increase through time. From a spatial point of view, all indices clearly singled out Corsica Island as having higher average originality and specialization. Finally, we observed that the originality index based on niche traits might be used as an informative biodiversity indicator because we showed it is sensitive to different land use classes along a landscape artificialization gradient. Moreover, its response remained unchanged over two other land use classifications at the global scale and also at the regional scale.

  4. When does fishing lead to more fish? Community consequences of bottom trawl fisheries in demersal food webs.

    Science.gov (United States)

    van Denderen, P Daniel; van Kooten, Tobias; Rijnsdorp, Adriaan D

    2013-10-22

    Bottom trawls are a globally used fishing gear that physically disturb the seabed and kill non-target organisms, including those that are food for the targeted fish species. There are indications that ensuing changes to the benthic invertebrate community may increase the availability of food and promote growth and even fisheries yield of target fish species. If and how this occurs is the subject of ongoing debate, with evidence both in favour and against. We model the effects of trawling on a simple ecosystem of benthivorous fish and two food populations (benthos), susceptible and resistant to trawling. We show that the ecosystem response to trawling depends on whether the abundance of benthos is top-down or bottom-up controlled. Fishing may result in higher fish abundance, higher (maximum sustainable) yield and increased persistence of fish when the benthos which is the best-quality fish food is also more resistant to trawling. These positive effects occur in bottom-up controlled systems and systems with limited impact of fish feeding on benthos, resembling bottom-up control. Fishing leads to lower yields and fish persistence in all configurations where susceptible benthos are more profitable prey. Our results highlight the importance of mechanistic ecosystem knowledge as a requirement for successful management.

  5. Association of fish and fish liver oil intake in pregnancy with infant size at birth among women of normal weight before pregnancy in a fishing community.

    Science.gov (United States)

    Thorsdottir, Inga; Birgisdottir, Bryndis E; Halldorsdottir, Sveinbjorg; Geirsson, Reynir T

    2004-09-01

    This 1998 study investigated the association between intake of fish and fish oil during pregnancy and full-term infants' size at birth in an Icelandic fishing community. Healthy women aged 20-40 years of normal weight before pregnancy (body mass index: 19.5-25.5 kg/m(2)) and at 38-43 weeks of gestation were selected randomly. Information on infant size at birth was collected from maternity records. Intake of fish and fish oil in pregnancy was ascertained (n = 491, 80.1%) by using a validated, focused, food frequency questionnaire. Infants of women in the lowest quartile of fish consumption weighed less (p = 0.036), were shorter (p fish. Infants of women in the highest quartile of fish oil intake (> or =1 tablespoon (11 ml)/day), consuming threefold the recommended dietary allowance of vitamin A and twofold that of vitamin D, were shorter (p = 0.036) and had a smaller head circumference (p = 0.003) than those of women consuming less. Infant size at birth increased with fish consumption, especially for women in the lower quartiles of consumption. Smaller birth size was linked to the highest levels of fish oil intake. Constituents of fish and fish oil might affect birth size differently depending on the amount consumed.

  6. Changes in the fish community and water quality during seven years of stocking piscivorous fish in a shallow lake

    DEFF Research Database (Denmark)

    Skov, Christian; Perrow, M.R.; Berg, Søren

    2002-01-01

    zooplanktivorous and benthivorous fish, with resultant effects on lower trophic levels and ultimately water quality. 2. The fish community and water quality parameters (Secchi depth, concentrations of total phosphorus, chlorophyll a and suspended solids) were monitored between 1996 and 2000 and relationships were...... evaluated between predatory fish and potential prey and between zooplanktivorous or benthivorous fish and water quality parameters. In addition, potential consumption of piscivorous fishes was calculated. 3. The density of fish feeding on larger zooplankton or benthos (roach >15 cm, crucian carp >15 cm......1. Piscivores (annual stocking of 1000 individuals ha(-1) of 0+ pike and a single stocking of 30 kg ha(-1) of large 20-30 cm perch) were stocked in seven consecutive years in a shallow eutrophic lake in Denmark. The stocking programme aimed at changing food-web structure by reducing...

  7. Changes in the fish community and water quality during seven years of stocking piscivorous fish in a shallow lake

    DEFF Research Database (Denmark)

    Skov, Christian; Perrow, M.R.; Berg, Søren;

    2002-01-01

    zooplanktivorous and benthivorous fish, with resultant effects on lower trophic levels and ultimately water quality. 2. The fish community and water quality parameters (Secchi depth, concentrations of total phosphorus, chlorophyll a and suspended solids) were monitored between 1996 and 2000 and relationships were...... evaluated between predatory fish and potential prey and between zooplanktivorous or benthivorous fish and water quality parameters. In addition, potential consumption of piscivorous fishes was calculated. 3. The density of fish feeding on larger zooplankton or benthos (roach >15 cm, crucian carp >15 cm...... 0+ pike was detected on 0+ roach. 4. A major decline in the recruitment strength of 0+ roach was observed in 2000. A combination of (i) the indirect effect of large pike preying on adult roach, with negative effect on roach reproduction and (ii) the direct predation effect of 0+ pike and or 1+ and 2...

  8. Repeated and Widespread Evolution of Bioluminescence in Marine Fishes.

    Science.gov (United States)

    Davis, Matthew P; Sparks, John S; Smith, W Leo

    2016-01-01

    Bioluminescence is primarily a marine phenomenon with 80% of metazoan bioluminescent genera occurring in the world's oceans. Here we show that bioluminescence has evolved repeatedly and is phylogenetically widespread across ray-finned fishes. We recover 27 independent evolutionary events of bioluminescence, all among marine fish lineages. This finding indicates that bioluminescence has evolved many more times than previously hypothesized across fishes and the tree of life. Our exploration of the macroevolutionary patterns of bioluminescent lineages indicates that the present day diversity of some inshore and deep-sea bioluminescent fish lineages that use bioluminescence for communication, feeding, and reproduction exhibit exceptional species richness given clade age. We show that exceptional species richness occurs particularly in deep-sea fishes with intrinsic bioluminescent systems and both shallow water and deep-sea lineages with luminescent systems used for communication.

  9. Community based fish culture in the public and private floodplains of Bangladesh

    NARCIS (Netherlands)

    Mahfuzul Haque, A.B.

    2015-01-01

    Seasonal floodplains are water bodies that retain water for 5-6 months during which they are suitable to grow fish and other aquatic animals. Out of 2.8 million ha of medium and deep-flooded areas, about 1.5 million ha are estimated to be suitable for Community-Based Fish Culture (CBFC). WorldFish h

  10. Fish's Constructions of the Interpretive Community, the Parol Evidence Rule, and the First Amendment.

    Science.gov (United States)

    Cauthen, Cramer R.

    Despite Stanley Fish's assertion that the interpretive communities basic to his theory of literary and legal interpretation are "engines of change," it seems clear that in Fish's conception of change, "plus ca change, c'est plus la meme chose." In particular, Fish denies that the legal profession can achieve the more…

  11. Community based fish culture in the public and private floodplains of Bangladesh

    NARCIS (Netherlands)

    Mahfuzul Haque, A.B.

    2015-01-01

    Seasonal floodplains are water bodies that retain water for 5-6 months during which they are suitable to grow fish and other aquatic animals. Out of 2.8 million ha of medium and deep-flooded areas, about 1.5 million ha are estimated to be suitable for Community-Based Fish Culture (CBFC). WorldFish h

  12. Community based fish culture in the public and private floodplains of Bangladesh

    NARCIS (Netherlands)

    Mahfuzul Haque, A.B.

    2015-01-01

    Seasonal floodplains are water bodies that retain water for 5-6 months during which they are suitable to grow fish and other aquatic animals. Out of 2.8 million ha of medium and deep-flooded areas, about 1.5 million ha are estimated to be suitable for Community-Based Fish Culture (CBFC). WorldFish

  13. Evolution properties of the community members for dynamic networks

    Science.gov (United States)

    Yang, Kai; Guo, Qiang; Li, Sheng-Nan; Han, Jing-Ti; Liu, Jian-Guo

    2017-03-01

    The collective behaviors of community members for dynamic social networks are significant for understanding evolution features of communities. In this Letter, we empirically investigate the evolution properties of the new community members for dynamic networks. Firstly, we separate data sets into different slices, and analyze the statistical properties of new members as well as communities they joined in for these data sets. Then we introduce a parameter φ to describe community evolution between different slices and investigate the dynamic community properties of the new community members. The empirical analyses for the Facebook, APS, Enron and Wiki data sets indicate that both the number of new members and joint communities increase, the ratio declines rapidly and then becomes stable over time, and most of the new members will join in the small size communities that is s ≤ 10. Furthermore, the proportion of new members in existed communities decreases firstly and then becomes stable and relatively small for these data sets. Our work may be helpful for deeply understanding the evolution properties of community members for social networks.

  14. Drowning among the lakeside fishing communities in Uganda: results of a community survey.

    Science.gov (United States)

    Kobusingye, Olive; Tumwesigye, Nazarius Mbona; Magoola, Joseph; Atuyambe, Lynn; Olange, Olakunle

    2017-09-01

    The study aimed to determine the drowning burden in four Ugandan lakeside districts; the prevalence of life jacket use, and community knowledge and attitudes regarding water safety. Subjects were recruited as they disembarked from boats. A structured questionnaire was used for demographics, experience on water, details of incidents in water, and awareness of drowning prevention measures. Focus group discussions (FGDs) and key informant interviews were held. The study interviewed 544 participants; 81.1% male, 86.8% below 45 years, and 51.1% involved in the fishing industry. A quarter (26.1%) of the respondents were observed wearing life jackets as they disembarked. Participants who had been in a boat that nearly capsized (57.8%), or that actually capsized (21.7%), were no more likely to wear life jackets than those who had not had these experiences. Three quarters (73.2%) did not know how to call for rescue, and only 48.7% could swim. There drowning fatality rate in this community was 502 deaths per 100,000 population. Majority of drowning events occurred during transportation (51.7%) or fishing (39.0%). The most frequently mentioned factors were stormy weather and overloading. Drowning is a common threat to young adults in the fishing communities around Lake Victoria. Few preventive interventions are in place.

  15. Summer Fish Communities in Northern Gulf of Mexico Estuaries: Indices of Ecological Condition

    Science.gov (United States)

    We used fish community data from trawl samples in >100 estuaries, bayous, and coastal lagoons of the Louisianan Biogeographic Province (Gulf of Mexico) to develop indicators of ecological condition. One data set, from which we derived reference values for fish community indicator...

  16. Community evolution mining and analysis in social network

    Science.gov (United States)

    Liu, Hongtao; Tian, Yuan; Liu, Xueyan; Jian, Jie

    2017-03-01

    With the development of digital and network technology, various social platforms emerge. These social platforms have greatly facilitated access to information, attracting more and more users. They use these social platforms every day to work, study and communicate, so every moment social platforms are generating massive amounts of data. These data can often be modeled as complex networks, making large-scale social network analysis possible. In this paper, the existing evolution classification model of community has been improved based on community evolution relationship over time in dynamic social network, and the Evolution-Tree structure is proposed which can show the whole life cycle of the community more clearly. The comparative test result shows that the improved model can excavate the evolution relationship of the community well.

  17. [Rapid ecological assessment of tropical fish communities in a gold mine area of Costa Rica].

    Science.gov (United States)

    Espinoza Mendiola, Mario

    2008-12-01

    Gold mining impacts have generated a great concern regarding aquatic systems and habitat fragmentation. Anthropogenic disturbances on the structure and heterogeneity of a system can have an important effect on aquatic community stability. Ecological rapid assessments (1996, 2002, and 2007) were employed to determine the structure, composition and distribution of tropical fish communities in several rivers and smaller creeks from a gold mining area in Cerro Crucitas, Costa Rica. In addition, species composition and relative abundance were related with habitat structure. A total of 35 species were registered, among which sardine Astyanax aeneus (Characidae) and livebearer Alfaro cultratus (Poeciliidae) were the most abundant fish (71%). The highest species richness was observed in Caño Crucitas (s=19) and Minas Creek (s=18). Significant differences in fish communities structure and composition from Infiernillo river and Minas creek were observed (lamda = 0.0, F(132, 66) = 2.24, p fish species and habitat structure was observed. This study reveals a high complexity in tropical fish communities that inhabit a gold mine area. Furthermore, it highlights the importance of habitat heterogeneity in fish community dynamics. The loss and degradation of aquatic systems in Cerro Crucitas can have a strong negative effect on fish community structure and composition of local species. A better understanding of the use of specific habitats that serve as essential fish habitats can improve tropical fish conservation and management strategies, thus increasing local diversity, and thereby, the biological importance of the area.

  18. Quantifying the Human Impacts on Papua New Guinea Reef Fish Communities across Space and Time.

    Directory of Open Access Journals (Sweden)

    Joshua A Drew

    Full Text Available Describing the drivers of species loss and of community change are important goals in both conservation and ecology. However, it is difficult to determine whether exploited species decline due to direct effects of harvesting or due to other environmental perturbations brought about by proximity to human populations. Here we quantify differences in species richness of coral reef fish communities along a human population gradient in Papua New Guinea to understand the relative impacts of fishing and environmental perturbation. Using data from published species lists we categorize the reef fishes as either fished or non-fished based on their body size and reports from the published literature. Species diversity for both fished and non-fished groups decreases as the size of the local human population increases, and this relationship is stronger in species that are fished. Additionally, comparison of modern and museum collections show that modern reef communities have proportionally fewer fished species relative to 19th century ones. Together these findings show that the reef fish communities of Papua New Guinea experience multiple anthropogenic stressors and that even at low human population levels targeted species experience population declines across both time and space.

  19. Quantifying the Human Impacts on Papua New Guinea Reef Fish Communities across Space and Time.

    Science.gov (United States)

    Drew, Joshua A; Amatangelo, Kathryn L; Hufbauer, Ruth A

    2015-01-01

    Describing the drivers of species loss and of community change are important goals in both conservation and ecology. However, it is difficult to determine whether exploited species decline due to direct effects of harvesting or due to other environmental perturbations brought about by proximity to human populations. Here we quantify differences in species richness of coral reef fish communities along a human population gradient in Papua New Guinea to understand the relative impacts of fishing and environmental perturbation. Using data from published species lists we categorize the reef fishes as either fished or non-fished based on their body size and reports from the published literature. Species diversity for both fished and non-fished groups decreases as the size of the local human population increases, and this relationship is stronger in species that are fished. Additionally, comparison of modern and museum collections show that modern reef communities have proportionally fewer fished species relative to 19th century ones. Together these findings show that the reef fish communities of Papua New Guinea experience multiple anthropogenic stressors and that even at low human population levels targeted species experience population declines across both time and space.

  20. Shallow reef fish communities of South Bahia coast, Brazil

    Directory of Open Access Journals (Sweden)

    Laís de C. T. Chaves

    2010-01-01

    Full Text Available This study aims to describe for the first time the fish community structure of five shallow reefs located off the cities of Santa Cruz de Cabrália and Porto Seguro (Araripe-AR, Itacipanema-IT, Alagados-AL, Naufrágio-NA and Recife de Fora Marine Park-RF Reefs, South Bahia, Northeastern Brazil. Fish density and richness were assessed through stationary point counts of 2 m radius for small cryptic species and 3 m for more conspicuous species. A total of 1 802 fishes belonging to 23 families and 54 species were observed. The most abundant species were the pomacentrids Stegastes fuscus and Abudefduf saxatilis. No significant differences were found for species richness or density of conspicuous species, but density of small cryptic species was low on reefs with high bottom rugosity, where there were more holes and crevices available. Herbivores were dominant on AR, AL and RF, invertivores on AL and both groups were dominant on IT. Some habitat variables such as rugosity and benthic cover were strongly correlated to species and sites. High bottom heterogeneity was found among reefs but they still presented similar species composition, richness and density. Within small-scale studies, such similarities in composition and richness are to be expected for reef fish communities, as most of the species concerned have a wide distribution range.Este trabalho descreve pela primeira vez as comunidades de peixes em cinco recifes rasos de Santa Cruz de Cabrália e Porto Seguro (Araripe-AR, Itacipanema-IT, Alagados-AL, Naufrágio-NA e Recife de Fora Marine Park-RF, sul da Bahia, nordeste do Brasil. A densidade e riqueza foram obtidas utilizando censos estacionários de 2 m de raio para espécies pequenas e criptobênticas e 3 m de raio para espécies conspícuas. Um total de 1802 peixes pertencentes a 23 famílias e 54 espécies foram registrados, sendo as espécies mais abundantes dos pomacentrídeos Stegastes fuscus e Abudefduf saxatilis. Nenhuma diferen

  1. At the interface of behaviour, ecology and evolution: Insights from the world of fishes

    Institute of Scientific and Technical Information of China (English)

    Scott PAVEY; Julian J. DODSON

    2012-01-01

    We are pleased to present this special issue of Current Zoology entitled "Behaviour,Ecology and Evolution of Fishes".The goal of this special issue is to showcase some of the recent developments in research occurring at the interface of fish behavioral ecology and evolution and to stimulate further research in this fascinating field.Most,but not all,of the papers fall under specific themes we identified in the call for submissions for this special issue.The issue features four review articles and fourteen original articles.The first review article,by Ⅰ.C(o)té and S.Green,describes the potential interactions of climate change with invasive species using the invasive lion fish in the Caribbean as an example.J.Weis and A.Candelmo review the literature and describe recent experiments testing the effects of pollutants on fish behavior,using the Mummichog and bluefish as the study organisms.

  2. The importance of being cis: evolution of orthologous fish and mammalian enhancer activity.

    Science.gov (United States)

    Ritter, Deborah I; Li, Qiang; Kostka, Dennis; Pollard, Katherine S; Guo, Su; Chuang, Jeffrey H

    2010-10-01

    Conserved noncoding elements (CNEs) in vertebrate genomes often act as developmental enhancers, but a critical issue is how well orthologous CNE sequences retain the same activity in their respective species, a characteristic important for generalization of model organism studies. To quantify how well CNE enhancer activity has been preserved, we compared the anatomy-specific activities of 41 zebra fish CNEs in zebra fish embryos with the activities of orthologous human CNEs in mouse embryos. We found that 13/41 (∼30%) of the orthologous CNE pairs exhibit conserved positive activity in zebra fish and mouse. Conserved positive activity is only weakly associated with either sequence conservation or the absence of bases undergoing accelerated evolution. A stronger effect is that disparate activity is associated with transcription factor binding site divergence. To distinguish the contributions of cis- versus trans-regulatory changes, we analyzed 13 CNEs in a three-way experimental comparison: human CNE tested in zebra fish, human CNE tested in mouse, and orthologous zebra fish CNE tested in zebra fish. Both cis- and trans-changes affect a significant fraction of CNEs, although human and zebra fish sequences exhibit disparate activity in zebra fish (indicating cis regulatory changes) twice as often as human sequences show disparate activity when tested in mouse and zebra fish (indicating trans regulatory changes). In all four cases where the zebra fish and human CNE display a similar expression pattern in zebra fish, the human CNE also displays a similar expression pattern in mouse. This suggests that the endogenous enhancer activity of ∼30% of human CNEs can be determined from experiments in zebra fish alone, and to identify these CNEs, both the zebra fish and the human sequences should be tested.

  3. Molecular evolution of hemoglobins of Antarctic fishes (Notothenioidei)

    NARCIS (Netherlands)

    Stam, W.T.; Beintema, J.J; D Avino, R.; Tamburrini, M.; di Prisco, G.

    1997-01-01

    Amino acid sequences of alpha- and beta-chains of human hemoglobin and of hemoglobins of coelacanth and 24 teleost fish species, including 11 antarctic and two temperate Notothenioidei, were analyzed using maximum parsimony. Trees were derived for the alpha- and beta-chains separately and for tandem

  4. Predictability of littoral-zone fish communities through ontogeny in Lake Texoma, Oklahoma-Texas, USA

    Science.gov (United States)

    Eggleton, M.A.; Ramirez, R.; Hargrave, C.W.; Gido, K.B.; Masoner, J.R.; Schnell, G.D.; Matthews, W.J.

    2005-01-01

    We sampled larval, juvenile and adult fishes from littoral-zone areas of a large reservoir (Lake Texoma, Oklahoma-Texas) (1) to characterize environmental factors that influenced fish community structure, (2) to examine how consistent fish-environment relationships were through ontogeny (i.e., larval vs. juvenile and adult), and (3) to measure the concordance of larval communities sampled during spring to juvenile and adult communities sampled at the same sites later in the year. Larval, juvenile and adult fish communities were dominated by Atherinidae (mainly inland silverside, Menidia beryllina) and Moronidae (mainly juvenile striped bass, Morone saxatilis) and were consistently structured along a gradient of site exposure to prevailing winds and waves. Larval, juvenile and adult communities along this gradient varied from atherinids and moronids at highly exposed sites to mostly centrarchids (primarily Lepomis and Micropterus spp.) at protected sites. Secondarily, zooplankton densities, water clarity, and land-use characteristics were related to fish community structure. Rank correlation analyses and Mantel tests indicated that the spatial consistency and predictability of fish communities was high as larval fishes sampled during spring were concordant with juvenile and adult fishes sampled at the same sites during summer and fall in terms of abundance, richness, and community structure. We propose that the high predictability and spatial consistency of littoral-zone fishes in Lake Texoma was a function of relatively simple communities (dominated by 1-2 species) that were structured by factors, such as site exposure to winds and waves, that varied little through time. ?? Springer 2005.

  5. Community core evolution in mobile social networks.

    Science.gov (United States)

    Xu, Hao; Xiao, Weidong; Tang, Daquan; Tang, Jiuyang; Wang, Zhenwen

    2013-01-01

    Community detection in social networks attracts a lot of attention in the recent years. Existing methods always depict the relationship of two nodes using the temporary connection. However, these temporary connections cannot be fully recognized as the real relationships when the history connections among nodes are considered. For example, a casual visit in Facebook cannot be seen as an establishment of friendship. Hence, our question is the following: how to cluster the real friends in mobile social networks? In this paper, we study the problem of detecting the stable community core in mobile social networks. The cumulative stable contact is proposed to depict the relationship among nodes. The whole process is divided into timestamps. Nodes and their connections can be added or removed at each timestamp, and historical contacts are considered when detecting the community core. Also, community cores can be tracked through the incremental computing, which can help to recognize the evolving of community structure. Empirical studies on real-world social networks demonstrate that our proposed method can effectively detect stable community cores in mobile social networks.

  6. Community Core Evolution in Mobile Social Networks

    Directory of Open Access Journals (Sweden)

    Hao Xu

    2013-01-01

    Full Text Available Community detection in social networks attracts a lot of attention in the recent years. Existing methods always depict the relationship of two nodes using the temporary connection. However, these temporary connections cannot be fully recognized as the real relationships when the history connections among nodes are considered. For example, a casual visit in Facebook cannot be seen as an establishment of friendship. Hence, our question is the following: how to cluster the real friends in mobile social networks? In this paper, we study the problem of detecting the stable community core in mobile social networks. The cumulative stable contact is proposed to depict the relationship among nodes. The whole process is divided into timestamps. Nodes and their connections can be added or removed at each timestamp, and historical contacts are considered when detecting the community core. Also, community cores can be tracked through the incremental computing, which can help to recognize the evolving of community structure. Empirical studies on real-world social networks demonstrate that our proposed method can effectively detect stable community cores in mobile social networks.

  7. Species-specific mercury bioaccumulation in a diverse fish community.

    Science.gov (United States)

    Donald, David B; Wissel, Björn; Anas, M U Mohamed

    2015-12-01

    Mercury bioaccumulation models developed for fish provide insight into the sources and transfer of Hg within ecosystems. Mercury concentrations were assessed for 16 fish species of the western reach of Lake Diefenbaker, Saskatchewan, Canada. For top predators (northern pike, Esox Lucius; walleye, Sander vitreum), Hg concentrations were positively correlated to δ(15)N, and δ(15)N to fish age, suggesting that throughout life these fish fed on organisms with increasingly higher trophic values and Hg concentrations. However, fish mass and/or age were the principal parameters related to Hg concentrations for most species. For 9 common species combined, individual variation in Hg concentration was explained in declining order of importance by fish mass, trophic position (δ(15)N), and fish age. Delta (15)N value was not the leading variable related to Hg concentration for the assemblage, probably because of the longevity of lower--trophic-level species (3 species ≥ 20 yr), substantial overlap in Hg concentration and δ(15)N values for large-bodied fish up to 3000 g, and complex relationships between Hg concentration and δ(15)N among species. These results suggest that the quantity of food (and Hg) consumed each year and converted to fish mass, the quantity of Hg bioaccumulated over years and decades, and trophic position were significant determinants of Hg concentration in Lake Diefenbaker fish.

  8. Impact of deep-water fish farms on benthic macrofauna communities under different hydrodynamic conditions.

    Science.gov (United States)

    Valdemarsen, Thomas; Hansen, Pia Kupka; Ervik, Arne; Bannister, Raymond J

    2015-12-30

    In this study the environmental impacts of two fish farms located over deep water (180-190 m) were compared. MC-Farm was located at a site with slightly higher water currents (mean current speed 3-5 cms(-1)) than LC-farm (fish farms should not be sited in low current areas (fish farming at slightly more dynamic sites can lead to stimulated benthic macrofauna communities and only moderate environmental impacts.

  9. PISCATOR, an individual-based model to analyze the dynamics of lake fish communities

    NARCIS (Netherlands)

    Nes, van E.H.; Lammens, E.H.R.R.; Scheffer, M.

    2002-01-01

    Unraveling the mechanisms that drive dynamics of multi-species fish communities is notoriously difficult. Not only are the interactions between fish populations complex, but also the functional niche of individual animals changes profoundly as they grow, making variation in size within populations a

  10. Evidence of a Shift in the Littoral Fish Community of the Sacramento-San Joaquin Delta

    National Research Council Canada - National Science Library

    Mahardja, Brian; Farruggia, Mary Jade; Schreier, Brian; Sommer, Ted

    2017-01-01

    .... Over the past two decades, the Sacramento-San Joaquin Delta (Delta) in California, USA, saw a severe decline in pelagic fishes, a shift in zooplankton community composition, and a rapid expansion of invasive aquatic vegetation...

  11. Baseline assessment of fish and benthic communities of the Flower Garden Banks (NODC Accession 0118358)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The proposed work develop baseline information on fish and benthic communities within the Flower Garden Banks National Marine Sanctuary (FGBNMS). Surveys will employ...

  12. Baseline assessment of fish communities of the Flower Garden Banks (2010 - present): 2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The proposed work develop baseline information on fish and benthic communities within the Flower Garden Banks National Marine Sanctuary (FGBNMS). Surveys will...

  13. Baseline assessment of fish and benthic communities of the Flower Garden Banks (NODC Accession 0118358)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The proposed work develop baseline information on fish and benthic communities within the Flower Garden Banks National Marine Sanctuary (FGBNMS). Surveys will...

  14. Baseline assessment of fish communities of the Flower Garden Banks (2010 - present): 2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The proposed work develop baseline information on fish and benthic communities within the Flower Garden Banks National Marine Sanctuary (FGBNMS). Surveys will employ...

  15. Baseline assessment of fish and benthic communities of the Flower Garden Banks

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The work developed baseline information on fish and benthic communities within the Flower Garden Banks National Marine Sanctuary (FGBNMS). Surveys employed diving,...

  16. Baseline assessment of the fish and benthic communities of the Flower Garden Banks (NODC Accession 0118358)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The proposed work develop baseline information on fish and benthic communities within the Flower Garden Banks National Marine Sanctuary (FGBNMS). Surveys will employ...

  17. A model for evolution of overlapping community networks

    Science.gov (United States)

    Karan, Rituraj; Biswal, Bibhu

    2017-05-01

    A model is proposed for the evolution of network topology in social networks with overlapping community structure. Starting from an initial community structure that is defined in terms of group affiliations, the model postulates that the subsequent growth and loss of connections is similar to the Hebbian learning and unlearning in the brain and is governed by two dominant factors: the strength and frequency of interaction between the members, and the degree of overlap between different communities. The temporal evolution from an initial community structure to the current network topology can be described based on these two parameters. It is possible to quantify the growth occurred so far and predict the final stationary state to which the network is likely to evolve. Applications in epidemiology or the spread of email virus in a computer network as well as finding specific target nodes to control it are envisaged. While facing the challenge of collecting and analyzing large-scale time-resolved data on social groups and communities one faces the most basic questions: how do communities evolve in time? This work aims to address this issue by developing a mathematical model for the evolution of community networks and studying it through computer simulation.

  18. Fish community structure and distribution in a macro-tidal inshore habitat in the Irish Sea

    Science.gov (United States)

    Jovanovic, Boris; Longmore, Craig; O'Leary, Áine; Mariani, Stefano

    2007-10-01

    Estuaries, lagoons and mudflat habitats represent a crucial biodiversity component in coastal waters and may act as vital nurseries and shelters for the juvenile stages of many commercial fish species. A study of the spatial distribution of inshore fish fauna around the shallow coastal habitats of North Bull Island (Dublin Bay, Ireland) was carried out during summer and autumn of 2005, in order to characterise the fish community present therein. Four stations were examined, situated along a putative environmental gradient, between the mudflat and the open sea shore. Stations were surveyed at both high and low tide and sampling was repeated weekly for eight weeks, spanning over four spring and four neap tidal events. A total of 17 fish species were caught, belonging to 13 families. The community was largely dominated by the lesser sandeel ( Ammodytes tobianus) and the common goby ( Pomatoschistus microps). Ordination techniques were used to generate hypotheses as to the general patterns in the fish community; Shannon-Wiener index was employed to estimate spatial, temporal and tidal trends in diversity; and analysis of variance (ANOVA) was employed to test for the influence of time of the year, habitat, tidal phase and tidal state on the spatial distribution of fishes. Results reveal that time of the year and habitat variation across the environmental gradient are the major factors in determining fish community structure. The influence of tidal dynamics seem to have a lesser impact on the overall community, but can significantly and variably affect the distribution of individual species.

  19. Community structure and biogeography of shore fishes in the Gulf of Aqaba, Red Sea

    Science.gov (United States)

    Khalaf, Maroof A.; Kochzius, Marc

    2002-02-01

    Shore fish community structure off the Jordanian Red Sea coast was determined on fringing coral reefs and in a seagrass-dominated bay at 6 m and 12 m depths. A total of 198 fish species belonging to 121 genera and 43 families was recorded. Labridae and Pomacentridae dominated the ichthyofauna in terms of species richness and Pomacentridae were most abundant. Neither diversity nor species richness was correlated to depth. The abundance of fishes was higher at the deep reef slope, due to schooling planktivorous fishes. At 12 m depth abundance of fishes at the seagrass-dominated site was higher than on the coral reefs. Multivariate analysis demonstrated a strong influence on the fish assemblages by depth and benthic habitat. Fish species richness was positively correlated with hard substrate cover and habitat diversity. Abundance of corallivores was positively linked with live hard coral cover. The assemblages of fishes were different on the shallow reef slope, deep reef slope and seagrass meadows. An analysis of the fish fauna showed that the Gulf of Aqaba harbours a higher species richness than previously reported. The comparison with fish communities on other reefs around the Arabian Peninsula and Indian Ocean supported the recognition of an Arabian subprovince within the Indian Ocean. The affinity of the Arabian Gulf ichthyofauna to the Red Sea is not clear.

  20. Predicting evolution with generalized models of divergent selection: a case study with poeciliid fish.

    Science.gov (United States)

    Langerhans, R Brian

    2010-12-01

    Over the past century and half since the process of natural selection was first described, one enduring question has captivated many, "how predictable is evolution?" Because natural selection comprises deterministic components, the course of evolution may exhibit some level of predictability across organismal groups. Here, I provide an early appraisal of the utility of one particular approach to understanding the predictability of evolution: generalized models of divergent selection (GMDS). The GMDS approach is meant to provide a unifying framework for the science of evolutionary prediction, offering a means of better understanding the causes and consequences of phenotypic and genetic evolution. I describe and test a GMDS centered on the evolution of body shape, size of the gonopodium (sperm-transfer organ), steady-swimming abilities, fast-start swimming performance, and reproductive isolation between populations in Gambusia fishes (Family Poeciliidae). The GMDS produced some accurate evolutionary predictions in Gambusia, identifying variation in intensity of predation by piscivorous fish as a major factor driving repeatable and predictable phenotypic divergence, and apparently playing a key role in promoting ecological speciation. Moreover, the model's applicability seems quite general, as patterns of differentiation in body shape between predator regimes in many disparate fishes match the model's predictions. The fact that such a simple model could yield accurate evolutionary predictions in distantly related fishes inhabiting different geographic regions and types of habitat, and experiencing different predator species, suggests that the model pinpointed a causal factor underlying major, shared patterns of diversification. The GMDS approach appears to represent a promising method of addressing the predictability of evolution and identifying environmental factors responsible for driving major patterns of replicated evolution.

  1. Effects of marine reserves versus nursery habitat availability on structure of reef fish communities.

    Science.gov (United States)

    Nagelkerken, Ivan; Grol, Monique G G; Mumby, Peter J

    2012-01-01

    No-take marine fishery reserves sustain commercial stocks by acting as buffers against overexploitation and enhancing fishery catches in adjacent areas through spillover. Likewise, nursery habitats such as mangroves enhance populations of some species in adjacent habitats. However, there is lack of understanding of the magnitude of stock enhancement and the effects on community structure when both protection from fishing and access to nurseries concurrently act as drivers of fish population dynamics. In this study we test the separate as well as interactive effects of marine reserves and nursery habitat proximity on structure and abundance of coral reef fish communities. Reserves had no effect on fish community composition, while proximity to nursery habitat only had a significant effect on community structure of species that use mangroves or seagrass beds as nurseries. In terms of reef fish biomass, proximity to nursery habitat by far outweighed (biomass 249% higher than that in areas with no nursery access) the effects of protection from fishing in reserves (biomass 21% lower than non-reserve areas) for small nursery fish (≤ 25 cm total length). For large-bodied individuals of nursery species (>25 cm total length), an additive effect was present for these two factors, although fish benefited more from fishing protection (203% higher biomass) than from proximity to nurseries (139% higher). The magnitude of elevated biomass for small fish on coral reefs due to proximity to nurseries was such that nursery habitats seem able to overrule the usually positive effects on fish biomass by reef reserves. As a result, conservation of nursery habitats gains importance and more consideration should be given to the ecological processes that occur along nursery-reef boundaries that connect neighboring ecosystems.

  2. The Quality of Social Environment and Social Accessibility of Fishing Communities in West Sumatra, Indonesia

    Directory of Open Access Journals (Sweden)

    Noviarti Zulkarnaini

    2015-02-01

    Full Text Available This study explored quantitatively the quality of the social environment of the traditional fishing community and its relation to social access assistance in Padang, West Sumatera, Indonesia. The study applied three indicators: education, health, and family life. The result revealed that the overall level of social environment quality of the fishing community is high moderate (69.23, by which average score of education (68.50, health (76.86, and family life (62.34. The average social environment quality in urban areas is high moderate (71.39, while in rural areas is low moderate (66.18. T-test analysis of social quality showed that there is a significant difference to the social environment quality of life (t = 5.258** among fishing community in urban and rural areas. The access to social assistance does not improve the quality of social life (t=3.537**. Finally, the fishing community showed preference to access social assistance is consumptive rather than productive. This study suggested that in order to improve their quality of life in fishing community, the government should take into account the character of the area and the productive assistance programs.Key words: Quality of life, fishing communities, urban poor,  HDI

  3. Correlated evolution of body and fin morphology in the cichlid fishes.

    Science.gov (United States)

    Feilich, Kara L

    2016-10-01

    Body and fin shapes are chief determinants of swimming performance in fishes. Different configurations of body and fin shapes can suit different locomotor specializations. The success of any configuration is dependent upon the hydrodynamic interactions between body and fins. Despite the importance of body-fin interactions for swimming, there are few data indicating whether body and fin configurations evolve in concert, or whether these structures vary independently. The cichlid fishes are a diverse family whose well-studied phylogenetic relationships make them ideal for the study of macroevolution of ecomorphology. This study measured body, and caudal and median fin morphology from radiographs of 131 cichlid genera, using morphometrics and phylogenetic comparative methods to determine whether these traits exhibit correlated evolution. Partial least squares canonical analysis revealed that body, caudal fin, dorsal fin, and anal fin shapes all exhibited strong correlated evolution consistent with locomotor ecomorphology. Major patterns included the evolution of deep body profiles with long fins, suggestive of maneuvering specialization; and the evolution of narrow, elongate caudal peduncles with concave tails, a combination that characterizes economical cruisers. These results demonstrate that body shape evolution does not occur independently of other traits, but among a suite of other morphological changes that augment locomotor specialization. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  4. The evolution of communities in the international oil trade network

    Science.gov (United States)

    Zhong, Weiqiong; An, Haizhong; Gao, Xiangyun; Sun, Xiaoqi

    2014-11-01

    International oil trade is a subset of global trade and there exist oil trade communities. These communities evolve over time and provide clues of international oil trade patterns. A better understanding of the international oil trade patterns is necessary for governments in policy making. To study the evolution of trade communities in the international oil trade network, we set up unweighted and weighted oil trade network models based on complex network theory using data from 2002 to 2011. We detected the communities in the oil trade networks and analyzed their evolutionary properties and stabilities over time. We found that the unweighted and weighted international oil trade networks show many different features in terms of community number, community scale, distribution of countries, quality of partitions, and stability of communities. Two turning points occurred in the evolution of community stability in the international oil trade network. One is the year 2004-2005 which correlates with changes in demand and supply in the world oil market after the Iraq War, and the other is the year 2008-2009 which is connected to the 2008 financial crisis. Different causations of instability show different features and this should be considered by policy makers.

  5. Monogeneans of West African cichlid fish: evolution and cophylogenetic interactions.

    Directory of Open Access Journals (Sweden)

    Monika Mendlová

    Full Text Available The goals of this paper were to investigate phylogenetic and evolutionary patterns of cichlid fish from West Africa and their Cichlidogyrus and Scutogyrus monogenean parasites, to uncover the presence of host-parasite cospeciation and to assess the level of morphological adaptation in parasites. This required the following steps, each one representing specific objectives of this paper: (1 to build phylogenetic trees for Cichlidogyrus and Scutogyrus species based on ribosomal DNA sequences, (2 to investigate phylogenetic relationships within West African cichlid fish based on the analysis of mitochondrial cytochrome b DNA sequences, (3 to investigate host-parasite cophylogenetic history to gain clues on parasite speciation process, and (4 to investigate the link between the morphology of the attachment apparatus and parasite phylogeny. Phylogenetic analyses supported the monophyletic origin of the Cichlidogyrus/Scutogyrus group, and suggested that Cichlidogyrus is polyphyletic and that Scutogyrus is monophyletic. The phylogeny of Cichlidae supported the separation of mouthbrooders and substrate-brooders and is consistent with the hypothesis that the mouthbrooding behavior of Oreochromis and Sarotherodon evolved from substrate-brooding behavior. The mapping of morphological characters of the haptor onto the parasite phylogenetic tree suggests that the attachment organ has evolved from a very simple form to a more complex one. The cophylogenetic analyses indicated a significant fit between trees using distance-based tests, but no significant cospeciation signal using tree-based tests, suggesting the presence of parasite duplications and host switches on related host species. This shed some light on the diversification process of Cichlidogyrus species parasitizing West African cichlids.

  6. The North Sea fish community: past, present and future : background document for the 2011 National Nature Outlook

    NARCIS (Netherlands)

    Teal, L.R.

    2011-01-01

    Long-term changes in the North Sea fish community have been demonstrated both as trends in individual species, particular those subject to fishing pressure, as well as in the community as a whole. Trends in diversity, size structure, trophic level and size at maturation have been related to fishing

  7. The North Sea fish community: past, present and future : background document for the 2011 National Nature Outlook

    NARCIS (Netherlands)

    Teal, L.R.

    2011-01-01

    Long-term changes in the North Sea fish community have been demonstrated both as trends in individual species, particular those subject to fishing pressure, as well as in the community as a whole. Trends in diversity, size structure, trophic level and size at maturation have been related to fishing

  8. Fisheries portfolio diversification and turnover buffer Alaskan fishing communities from abrupt resource and market changes

    Science.gov (United States)

    Cline, Timothy J.; Schindler, Daniel E.; Hilborn, Ray

    2017-01-01

    Abrupt shifts in natural resources and their markets are a ubiquitous challenge to human communities. Building resilient social-ecological systems requires approaches that are robust to uncertainty and to regime shifts. Harvesting diverse portfolios of natural resources and adapting portfolios in response to change could stabilize economies reliant on natural resources and their markets, both of which are prone to unpredictable shifts. Here we use fisheries catch and revenue data from Alaskan fishing communities over 34 years to test whether diversification and turnover in the composition of fishing opportunities increased economic stability during major ocean and market regime shifts in 1989. More than 85% of communities show reduced fishing revenues following these regime shifts. However, communities with the highest portfolio diversity and those that could opportunistically shift the composition of resources they harvest, experienced negligible or even positive changes in revenue. Maintaining diversity in economic opportunities and enabling turnover facilitates sustainability of communities reliant on renewable resources facing uncertain futures. PMID:28091534

  9. Fisheries portfolio diversification and turnover buffer Alaskan fishing communities from abrupt resource and market changes.

    Science.gov (United States)

    Cline, Timothy J; Schindler, Daniel E; Hilborn, Ray

    2017-01-16

    Abrupt shifts in natural resources and their markets are a ubiquitous challenge to human communities. Building resilient social-ecological systems requires approaches that are robust to uncertainty and to regime shifts. Harvesting diverse portfolios of natural resources and adapting portfolios in response to change could stabilize economies reliant on natural resources and their markets, both of which are prone to unpredictable shifts. Here we use fisheries catch and revenue data from Alaskan fishing communities over 34 years to test whether diversification and turnover in the composition of fishing opportunities increased economic stability during major ocean and market regime shifts in 1989. More than 85% of communities show reduced fishing revenues following these regime shifts. However, communities with the highest portfolio diversity and those that could opportunistically shift the composition of resources they harvest, experienced negligible or even positive changes in revenue. Maintaining diversity in economic opportunities and enabling turnover facilitates sustainability of communities reliant on renewable resources facing uncertain futures.

  10. Mangroves enhance the biomass of coral reef fish communities in the Caribbean

    Science.gov (United States)

    Mumby, Peter J.; Edwards, Alasdair J.; Ernesto Arias-González, J.; Lindeman, Kenyon C.; Blackwell, Paul G.; Gall, Angela; Gorczynska, Malgosia I.; Harborne, Alastair R.; Pescod, Claire L.; Renken, Henk; C. C. Wabnitz, Colette; Llewellyn, Ghislane

    2004-02-01

    Mangrove forests are one of the world's most threatened tropical ecosystems with global loss exceeding 35% (ref. 1). Juvenile coral reef fish often inhabit mangroves, but the importance of these nurseries to reef fish population dynamics has not been quantified. Indeed, mangroves might be expected to have negligible influence on reef fish communities: juvenile fish can inhabit alternative habitats and fish populations may be regulated by other limiting factors such as larval supply or fishing. Here we show that mangroves are unexpectedly important, serving as an intermediate nursery habitat that may increase the survivorship of young fish. Mangroves in the Caribbean strongly influence the community structure of fish on neighbouring coral reefs. In addition, the biomass of several commercially important species is more than doubled when adult habitat is connected to mangroves. The largest herbivorous fish in the Atlantic, Scarus guacamaia, has a functional dependency on mangroves and has suffered local extinction after mangrove removal. Current rates of mangrove deforestation are likely to have severe deleterious consequences for the ecosystem function, fisheries productivity and resilience of reefs. Conservation efforts should protect connected corridors of mangroves, seagrass beds and coral reefs.

  11. Impact of 21st century climate change on the Baltic Sea fish community and fisheries

    DEFF Research Database (Denmark)

    MacKenzie, Brian; Gislason, Henrik; Möllmann, C.;

    2007-01-01

    reviewed. We then use recent regional - scale climate - ocean modelling results to consider how climate change during this century will affect the fish community of the Baltic and fisheries management. Expected climate changes in northern Europe will likely affect both the temperature and salinity...... some of the uncertainties and complexities associated with forecasting how fish populations, communities and industries dependent on an estuarine ecosystem might respond to future climate change.......The Baltic Sea is a large brackish semienclosed sea whose species-poor fish community supports important commercial and recreational fisheries. Both the fish species and the fisheries are strongly affected by climate variations. These climatic effects and the underlying mechanisms are briefly...

  12. Food resource partitioning in a fish community of the central Amazon floodplain

    Directory of Open Access Journals (Sweden)

    Bernard de Mérona

    Full Text Available Diets of most of fish species inhabiting a floodplain lake in central Amazonia were studied over a two years and half period. Based on the percentage of relative occurrence of 11 major food categories a classification of species in 11 feeding guilds is proposed. Many species were found to be specialized feeders. Fish, detritus and insects were the most important food resources supporting the fish community in both seasons, but the proportions of fruits, invertebrates and fish were reduced during the low water season. At the community level mean diet overlap between species was low, suggesting efficient resource partitioning within the community. However mean overlap between unspecialized feeders was high. Based on the 23 most abundant species belonging to the different feeding guilds, there was no difference in mean overlap between seasons. Whereas individual species exhibited diet changes between high water and low water seasons, there was no general pattern of seasonal change within feeding guilds.

  13. The Two Ecologies: Population and Community Perspectives on Organizational Evolution.

    Science.gov (United States)

    Astley, W. Graham

    1985-01-01

    This paper distinguishes between two ecological perspectives on organizational evolution: population ecology, which limits investigation to evolutionary change in established populations, and community ecology, which focuses on the rise and fall of populations themselves as basic units of evolutionary change. These perspectives produce contrasting…

  14. Diversity of bile salts in fish and amphibians: evolution of a complex biochemical pathway.

    Science.gov (United States)

    Hagey, Lee R; Møller, Peter R; Hofmann, Alan F; Krasowski, Matthew D

    2010-01-01

    Bile salts are the major end metabolites of cholesterol and are also important in lipid and protein digestion, as well as shaping of the gut microflora. Previous studies had demonstrated variation of bile salt structures across vertebrate species. We greatly extend prior surveys of bile salt variation in fish and amphibians, particularly in analysis of the biliary bile salts of Agnatha and Chondrichthyes. While there is significant structural variation of bile salts across all fish orders, bile salt profiles are generally stable within orders of fish and do not correlate with differences in diet. This large data set allowed us to infer evolutionary changes in the bile salt synthetic pathway. The hypothesized ancestral bile salt synthetic pathway, likely exemplified in extant hagfish, is simpler and much shorter than the pathway of most teleost fish and terrestrial vertebrates. Thus, the bile salt synthetic pathway has become longer and more complex throughout vertebrate evolution. Analysis of the evolution of bile salt synthetic pathways provides a rich model system for the molecular evolution of a complex biochemical pathway in vertebrates.

  15. Habitat dynamics, marine reserve status, and the decline and recovery of coral reef fish communities

    Science.gov (United States)

    Williamson, David H; Ceccarelli, Daniela M; Evans, Richard D; Jones, Geoffrey P; Russ, Garry R

    2014-01-01

    Severe climatic disturbance events often have major impacts on coral reef communities, generating cycles of decline and recovery, and in some extreme cases, community-level phase shifts from coral-to algal-dominated states. Benthic habitat changes directly affect reef fish communities, with low coral cover usually associated with low fish diversity and abundance. No-take marine reserves (NTRs) are widely advocated for conserving biodiversity and enhancing the sustainability of exploited fish populations. Numerous studies have documented positive ecological and socio-economic benefits of NTRs; however, the ability of NTRs to ameliorate the effects of acute disturbances on coral reefs has seldom been investigated. Here, we test these factors by tracking the dynamics of benthic and fish communities, including the important fishery species, coral trout (Plectropomus spp.), over 8 years in both NTRs and fished areas in the Keppel Island group, Great Barrier Reef, Australia. Two major disturbances impacted the reefs during the monitoring period, a coral bleaching event in 2006 and a freshwater flood plume in 2011. Both disturbances generated significant declines in coral cover and habitat complexity, with subsequent declines in fish abundance and diversity, and pronounced shifts in fish assemblage structure. Coral trout density also declined in response to the loss of live coral, however, the approximately 2:1 density ratio between NTRs and fished zones was maintained over time. The only post-disturbance refuges for coral trout spawning stocks were within the NTRs that escaped the worst effects of the disturbances. Although NTRs had little discernible effect on the temporal dynamics of benthic or fish communities, it was evident that the post-disturbance refuges for coral trout spawning stocks within some NTRs may be critically important to regional-scale population persistence and recovery. PMID:24634720

  16. Habitat dynamics, marine reserve status, and the decline and recovery of coral reef fish communities.

    Science.gov (United States)

    Williamson, David H; Ceccarelli, Daniela M; Evans, Richard D; Jones, Geoffrey P; Russ, Garry R

    2014-02-01

    Severe climatic disturbance events often have major impacts on coral reef communities, generating cycles of decline and recovery, and in some extreme cases, community-level phase shifts from coral-to algal-dominated states. Benthic habitat changes directly affect reef fish communities, with low coral cover usually associated with low fish diversity and abundance. No-take marine reserves (NTRs) are widely advocated for conserving biodiversity and enhancing the sustainability of exploited fish populations. Numerous studies have documented positive ecological and socio-economic benefits of NTRs; however, the ability of NTRs to ameliorate the effects of acute disturbances on coral reefs has seldom been investigated. Here, we test these factors by tracking the dynamics of benthic and fish communities, including the important fishery species, coral trout (Plectropomus spp.), over 8 years in both NTRs and fished areas in the Keppel Island group, Great Barrier Reef, Australia. Two major disturbances impacted the reefs during the monitoring period, a coral bleaching event in 2006 and a freshwater flood plume in 2011. Both disturbances generated significant declines in coral cover and habitat complexity, with subsequent declines in fish abundance and diversity, and pronounced shifts in fish assemblage structure. Coral trout density also declined in response to the loss of live coral, however, the approximately 2:1 density ratio between NTRs and fished zones was maintained over time. The only post-disturbance refuges for coral trout spawning stocks were within the NTRs that escaped the worst effects of the disturbances. Although NTRs had little discernible effect on the temporal dynamics of benthic or fish communities, it was evident that the post-disturbance refuges for coral trout spawning stocks within some NTRs may be critically important to regional-scale population persistence and recovery.

  17. Status of Coral Reef Fish Communities within the Mombasa Marine ...

    African Journals Online (AJOL)

    Keywords: Ecological monitoring, no-take area, partially-protected area, Marine ... abundance of haemulids (nocturnal carnivores) and acanthurids (herbivores) in ... This was also positively ... was little detectable effect on fish abundance.

  18. Challenges in using fish communities for assessing the ecological ...

    African Journals Online (AJOL)

    2009-10-02

    Oct 2, 2009 ... In South. Africa, the determination of the ecological Reserve is required .... Implementation and monitoring of Reserve specifications. 7. Reserve ... In a 2nd step, a list of reference fish species was compiled for each river ...

  19. Fish Ecology and Evolution in the World's Oxygen Minimum Zones and Implications of Ocean Deoxygenation.

    Science.gov (United States)

    Gallo, N D; Levin, L A

    Oxygen minimum zones (OMZs) and oxygen limited zones (OLZs) are important oceanographic features in the Pacific, Atlantic, and Indian Ocean, and are characterized by hypoxic conditions that are physiologically challenging for demersal fish. Thickness, depth of the upper boundary, minimum oxygen levels, local temperatures, and diurnal, seasonal, and interannual oxycline variability differ regionally, with the thickest and shallowest OMZs occurring in the subtropics and tropics. Although most fish are not hypoxia-tolerant, at least 77 demersal fish species from 16 orders have evolved physiological, behavioural, and morphological adaptations that allow them to live under the severely hypoxic, hypercapnic, and at times sulphidic conditions found in OMZs. Tolerance to OMZ conditions has evolved multiple times in multiple groups with no single fish family or genus exploiting all OMZs globally. Severely hypoxic conditions in OMZs lead to decreased demersal fish diversity, but fish density trends are variable and dependent on region-specific thresholds. Some OMZ-adapted fish species are more hypoxia-tolerant than most megafaunal invertebrates and are present even when most invertebrates are excluded. Expansions and contractions of OMZs in the past have affected fish evolution and diversity. Current patterns of ocean warming are leading to ocean deoxygenation, causing the expansion and shoaling of OMZs, which is expected to decrease demersal fish diversity and alter trophic pathways on affected margins. Habitat compression is expected for hypoxia-intolerant species, causing increased susceptibility to overfishing for fisheries species. Demersal fisheries are likely to be negatively impacted overall by the expansion of OMZs in a warming world.

  20. Molecular evolution of globin genes in Gymnotiform electric fishes: relation to hypoxia tolerance.

    Science.gov (United States)

    Tian, Ran; Losilla, Mauricio; Lu, Ying; Yang, Guang; Zakon, Harold

    2017-02-13

    Nocturnally active gymnotiform weakly electric fish generate electric signals for communication and navigation, which can be energetically taxing. These fish mainly inhabit the Amazon basin, where some species prefer well-oxygenated waters and others live in oxygen-poor, stagnant habitats. The latter species show morphological, physiological, and behavioral adaptations for hypoxia-tolerance. However, there have been no studies of hypoxia tolerance on the molecular level. Globins are classic respiratory proteins. They function principally in oxygen-binding and -delivery in various tissues and organs. Here, we investigate the molecular evolution of alpha and beta hemoglobins, myoglobin, and neuroglobin in 12 gymnotiforms compared with other teleost fish. The present study identified positively selected sites (PSS) on hemoglobin (Hb) and myoglobin (Mb) genes using different maximum likelihood (ML) methods; some PSS fall in structurally important protein regions. This evidence for the positive selection of globin genes suggests that the adaptive evolution of these genes has helped to enhance the capacity for oxygen storage and transport. Interestingly, a substitution of a Cys at a key site in the obligate air-breathing electric eel (Electrophorus electricus) is predicted to enhance oxygen storage of Mb and contribute to NO delivery during hypoxia. A parallel Cys substitution was also noted in an air-breathing African electric fish (Gymnarchus niloticus). Moreover, the expected pattern under normoxic conditions of high expression of myoglobin in heart and neuroglobin in the brain in two hypoxia-tolerant species suggests that the main effect of selection on these globin genes is on their sequence rather than their basal expression patterns. Results indicate a clear signature of positive selection in the globin genes of most hypoxia-tolerant gymnotiform fishes, which are obligate or facultative air breathers. These findings highlight the critical role of globin genes in

  1. Comprehensive transcriptome analysis reveals accelerated genic evolution in a Tibet fish, Gymnodiptychus pachycheilus.

    Science.gov (United States)

    Yang, Liandong; Wang, Ying; Zhang, Zhaolei; He, Shunping

    2014-12-26

    Elucidating the genetic mechanisms of organismal adaptation to the Tibetan Plateau at a genomic scale can provide insights into the process of adaptive evolution. Many highland species have been investigated and various candidate genes that may be responsible for highland adaptation have been identified. However, we know little about the genomic basis of adaptation to Tibet in fishes. Here, we performed transcriptome sequencing of a schizothoracine fish (Gymnodiptychus pachycheilus) and used it to identify potential genetic mechanisms of highland adaptation. We obtained totally 66,105 assembled unigenes, of which 7,232 were assigned as putative one-to-one orthologs in zebrafish. Comparative gene annotations from several species indicated that at least 350 genes lost and 41 gained since the divergence between G. pachycheilus and zebrafish. An analysis of 6,324 orthologs among zebrafish, fugu, medaka, and spotted gar identified consistent evidence for genome-wide accelerated evolution in G. pachycheilus and only the terminal branch of G. pachycheilus had an elevated Ka/Ks ratio than the ancestral branch. Many functional categories related to hypoxia and energy metabolism exhibited rapid evolution in G. pachycheilus relative to zebrafish. Genes showing signature of rapid evolution and positive selection in the G. pachycheilus lineage were also enriched in functions associated with energy metabolism and hypoxia. The first genomic resources for fish in the Tibetan Plateau and evolutionary analyses provided some novel insights into highland adaptation in fishes and served as a foundation for future studies aiming to identify candidate genes underlying the genetic bases of adaptation to Tibet in fishes.

  2. Evolution of the Sinus Venosus from Fish to Human

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    Bjarke Jensen

    2014-03-01

    Full Text Available The sinus venosus, the cardiac chamber upstream of the (right atrium, is a severely underinvestigated structure. Yet, its myocardium harbors the cardiac pacemaker in all vertebrates. In human, ectopic pacemaking and subsequent pathologies may originate from sinus venosus-derived myocardium surrounding the coronary sinus and the superior caval vein. In ectothermic vertebrates, i.e., fishes, amphibians and reptiles, the sinus venosus aids atrial filling by contracting prior to the atrium (atria. This is facilitated by the sinuatrial delay of approximately the same duration as the atrioventricular delay, which facilitates atrial filling of the ventricles. In mammals, the sinuatrial delay is lost, and the sinus venosus-derived myocardium persists as an extensive myocardial sheet surrounding the caval veins, which is activated in synchrony with the myocardium of the atria. The caval vein myocardium is hardly of significance in the healthy formed heart, but we suggest that the sinus venosus functions as a chamber during development when cardiac output, heart rate, blood pressure and architecture is much more like that of ectothermic vertebrates. The remodeling of the sinus venosus in mammals may be an adaptation associated with the high heart rates necessary for postnatal endothermy. If so, the endothermic birds should exhibit a similar remodeling as mammals, which remains to be investigated.

  3. Fish community dynamics following dam removal in a fragmented agricultural stream

    Science.gov (United States)

    Kornis, Matthew; Weidel, Brian C.; Powers, Stephens; Diebel, Matthew W.; Cline, Timpthy; Fox, Justin; Kitchell, James F.

    2014-01-01

    Habitat fragmentation impedes dispersal of aquatic fauna, and barrier removal is increasingly used to increase stream network connectivity and facilitate fish dispersal. Improved understanding of fish community response to barrier removal is needed, especially in fragmented agricultural streams where numerous antiquated dams are likely destined for removal. We examined post-removal responses in two distinct fish communities formerly separated by a small aging mill dam. The dam was removed midway through the 6 year study, enabling passage for downstream fishes affiliated with a connected reservoir into previously inaccessible habitat, thus creating the potential for taxonomic homogenization between upstream and downstream communities. Both communities changed substantially post-removal. Two previously excluded species (white sucker, yellow perch) established substantial populations upstream of the former dam, contributing to a doubling of total fish biomass. Meanwhile, numerical density of pre-existing upstream fishes declined. Downstream, largemouth bass density was inversely correlated with prey fish density throughout the study, while post-removal declines in bluegill density coincided with cooler water temperature and increased suspended and benthic fine sediment. Upstream and downstream fish communities became more similar post-removal, represented by a shift in Bray-Curtis index from 14 to 41 % similarity. Our findings emphasize that barrier removal in highly fragmented stream networks can facilitate the unintended and possibly undesirable spread of species into headwater streams, including dispersal of species from remaining reservoirs. We suggest that knowledge of dispersal patterns for key piscivore and competitor species in both the target system and neighboring systems may help predict community outcomes following barrier removal.

  4. Evolution of class switch recombination function in fish activation-induced cytidine deaminase, AID.

    Science.gov (United States)

    Wakae, Koshou; Magor, Brad G; Saunders, Holly; Nagaoka, Hitoshi; Kawamura, Akemi; Kinoshita, Kazuo; Honjo, Tasuku; Muramatsu, Masamichi

    2006-01-01

    Following activation of mammalian B cells, class switch recombination (CSR) and somatic hypermutation (SHM) of the Ig heavy chain (IgH) gene can improve the functions of the expressed antibodies. Activation-induced cytidine deaminase (AID) is the only known B cell-specific protein required for inducing CSR and SHM in mammals. Lower vertebrates have an AID homologue, and there is some evidence of SHM in vivo. However there is no evidence of CSR in the cartilaginous or bony fishes, and this may be due in part to a lack of cis-elements in the IgH gene that are the normal targets of AID-mediated recombination. We have tested whether bony fish (zebrafish and catfish) AID can mediate CSR and SHM in mammalian cells. As expected, ectopic expression of fish AID in mouse fibroblasts resulted in mutations in an introduced SHM reporter gene, indicating that fish AID can mediate SHM. Unexpectedly, expression of fish AID in mouse AID-/- B cells induced surface IgG expression as well as switched transcripts from Ig gene loci, clearly indicating that the fish AID protein can mediate CSR, at least in mouse cells. These results suggest that the AID protein acquired the ability to mediate CSR before the IgH locus evolved the additional exon clusters and switch regions that are the targets of recombination. We discuss how pleiotropic functions of specific domains within the AID protein may have facilitated the early evolution of CSR in lower vertebrates.

  5. From fish to fashion: experimental and theoretical insights into the evolution of culture

    Science.gov (United States)

    Laland, K. N.; Atton, N.; Webster, M. M.

    2011-01-01

    Recent years have witnessed a re-evaluation of the cognitive capabilities of fishes, including with respect to social learning. Indeed, some of the best experimental evidence for animal traditions can be found in fishes. Laboratory experimental studies reveal that many fishes acquire dietary, food site and mating preferences, predator recognition and avoidance behaviour, and learn pathways, through copying1 other fishes. Concentrating on foraging behaviour, we will present the findings of laboratory experiments that reveal social learning, behavioural innovation, the diffusion of novel behaviour through populations and traditional use of food sites. Further studies reveal surprisingly complex social learning strategies deployed by sticklebacks. We will go on to place these observations of fish in a phylogenetic context, describing in which respects the learning and traditionality of fish are similar to, and differ from, that observed in other animals. We end by drawing on theoretical insights to suggest processes that may have played important roles in the evolution of the human cultural capability. PMID:21357218

  6. Sodium channel genes and the evolution of diversity in communication signals of electric fishes: convergent molecular evolution.

    Science.gov (United States)

    Zakon, Harold H; Lu, Ying; Zwickl, Derrick J; Hillis, David M

    2006-03-07

    We investigated whether the evolution of electric organs and electric signal diversity in two independently evolved lineages of electric fishes was accompanied by convergent changes on the molecular level. We found that a sodium channel gene (Na(v)1.4a) that is expressed in muscle in nonelectric fishes has lost its expression in muscle and is expressed instead in the evolutionarily novel electric organ in both lineages of electric fishes. This gene appears to be evolving under positive selection in both lineages, facilitated by its restricted expression in the electric organ. This view is reinforced by the lack of evidence for selection on this gene in one electric species in which expression of this gene is retained in muscle. Amino acid replacements occur convergently in domains that influence channel inactivation, a key trait for shaping electric communication signals. Some amino acid replacements occur at or adjacent to sites at which disease-causing mutations have been mapped in human sodium channel genes, emphasizing that these replacements occur in functionally important domains. Selection appears to have acted on the final step in channel inactivation, but complementarily on the inactivation "ball" in one lineage, and its receptor site in the other lineage. Thus, changes in the expression and sequence of the same gene are associated with the independent evolution of signal complexity.

  7. Marine fish community structure and habitat associations on the Canadian Beaufort shelf and slope

    Science.gov (United States)

    Majewski, Andrew R.; Atchison, Sheila; MacPhee, Shannon; Eert, Jane; Niemi, Andrea; Michel, Christine; Reist, James D.

    2017-03-01

    Marine fishes in the Canadian Beaufort Sea have complex interactions with habitats and prey, and occupy a pivotal position in the food web by transferring energy between lower- and upper-trophic levels, and also within and among habitats (e.g., benthic-pelagic coupling). The distributions, habitat associations, and community structure of most Beaufort Sea marine fishes, however, are unknown thus precluding effective regulatory management of emerging offshore industries in the region (e.g., hydrocarbon development, shipping, and fisheries). Between 2012 and 2014, Fisheries and Oceans Canada conducted the first baseline survey of offshore marine fishes, their habitats, and ecological relationships in the Canadian Beaufort Sea. Benthic trawling was conducted at 45 stations spanning 18-1001 m depths across shelf and slope habitats. Physical oceanographic variables (depth, salinity, temperature, oxygen), biological variables (benthic chlorophyll and integrated water-column chlorophyll) and sediment composition (grain size) were assessed as potential explanatory variables for fish community structure using a non-parametric statistical approach. Selected stations were re-sampled in 2013 and 2014 for a preliminary assessment of inter-annual variability in the fish community. Four distinct fish assemblages were delineated on the Canadian Beaufort Shelf and slope: 1) Nearshore-shelf: 50 and ≤200 m depths, 3) Upper-slope: ≥200 and ≤500 m depths, and 4) Lower-slope: ≥500 m depths. Depth was the environmental variable that best explained fish community structure, and each species assemblage was spatially associated with distinct aspects of the vertical water mass profile. Significant differences in the fish community from east to west were not detected, and the species composition of the assemblages on the Canadian Beaufort Shelf have not changed substantially over the past decade. This community analysis provides a framework for testing hypotheses regarding the trophic

  8. Fishery-independent data reveal negative effect of human population density on Caribbean predatory fish communities.

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    Christopher D Stallings

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

  9. Taxonomy of USA east coast fishing communities in terms of social vulnerability and resilience

    Energy Technology Data Exchange (ETDEWEB)

    Pollnac, Richard B., E-mail: pollnac3@gmail.com [Department of Marine Affairs, University of Rhode Island, 1 Greenhouse Rd., Kingston, RI 02881 (United States); Seara, Tarsila, E-mail: tarsila.seara@noaa.gov [National Marine Fisheries Service, NOAA, Northeast Fisheries Science Center, Social Sciences Branch, 28 Tarzwell Dr., Narragansett, RI 02882 (United States); Colburn, Lisa L., E-mail: lisa.l.colburn@noaa.gov [National Marine Fisheries Service, NOAA, Northeast Fisheries Science Center, Social Sciences Branch, 28 Tarzwell Dr., Narragansett, RI 02882 (United States); Jepson, Michael, E-mail: michael.jepson@noaa.gov [National Marine Fisheries Service, NOAA, Southeast Fisheries Science Center, Social Sciences Branch, 263 13th Avenue South, Saint Petersburg, FL 33701 (United States)

    2015-11-15

    Increased concern with the impacts that changing coastal environments can have on coastal fishing communities led to a recent effort by NOAA Fisheries social scientists to develop a set of indicators of social vulnerability and resilience for the U.S. Southeast and Northeast coastal communities. A goal of the NOAA Fisheries social vulnerability and resilience indicator program is to support time and cost effective use of readily available data in furtherance of both social impact assessments of proposed changes to fishery management regulations and climate change adaptation planning. The use of the indicators to predict the response to change in coastal communities would be enhanced if community level analyses could be grouped effectively. This study examines the usefulness of combining 1130 communities into 35 relevant subgroups by comparing results of a numerical taxonomy with data collected by interview methods, a process herein referred to as “ground-truthing.” The validation of the taxonomic method by the method of ground-truthing indicates that the clusters are adequate to be used to select communities for in-depth research. - Highlights: • We develop a taxonomy of fishing communities based on vulnerability indicators. • We validate the community clusters through the use of surveys (“ground-truthing”). • Clusters differ along important aspects of fishing community vulnerability. • Clustering communities allows for accurate and timely social impact assessments.

  10. Carbon sources supporting a diverse fish community in a tropical coastal ecosystem (Gazi Bay, Kenya)

    Science.gov (United States)

    Nyunja, J.; Ntiba, M.; Onyari, J.; Mavuti, K.; Soetaert, K.; Bouillon, S.

    2009-07-01

    Interlinked mangrove-seagrass ecosystems are characteristic features of many tropical coastal areas, where they act as feeding and nursery grounds for a variety of fishes and invertebrates. The autotrophic carbon sources supporting fisheries in Gazi bay (Kenya) were studied in three sites, two located in the tidal creeks flowing through extensive mangrove forests, another site located in the subtidal seagrass meadows, approximately 2.5 km away from the forest. Carbon and nitrogen stable isotope composition of 42 fish species, 2 crustacean species and a range of potential primary food sources (e.g., mangroves, seagrasses and epiphytes, macroalgae) were analysed. There was considerable overlap in the δ 13C signatures between fish (-16.1 ± 2.1‰), seagrasses (-15.1 ± 3.0‰), seagrass epiphytes (-13.6 ± 3.3‰), and macroalgae (-20.4 ± 3.1‰). Nevertheless, the signatures for most primary producers were sufficiently distinct to indicate that the dominant carbon sources for fish were mainly derived from the seagrass and their associated epiphytic community, and possibly macroalgae. Mangrove-derived organic matter contributes only marginally to the overall fish food web. Carbon supporting these fish communities was derived directly through grazing by herbivorous and some omnivorous fishes, or indirectly through the benthic food web. Fishes from the mangrove creeks had distinctly lower δ 13C signatures (-16.8 ± 2.0‰) compared to those collected in the adjacent seagrass beds (-14.7 ± 1.7‰). This indicated that these habitats were used as distinct sheltering and feeding zones for the fishes collected, with minimal degree of exchange within the fish communities despite their regular movement pattern.

  11. Community structure of shallow rocky shore fish in a tropical bay of the southwestern Atlantic

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    Camilo Moitinho Ferreira

    2015-12-01

    Full Text Available Abstract Southwestern Atlantic Ocean rocky shores sustain important reef fish communities. However, those communities in tropical regions are not well understood, especially in Brazil. In this present article we assess community parameters of reef fishes such as composition, trophic organization and their relationships with physical and biological factors on four tropical rocky shores in Todos os Santos Bay, southwestern Atlantic. During six months, a total of 80 visual censuses were performed, in which 3,582 fish belonging to 76 species were recorded. Territorial herbivorous fish and turf algae were dominant at all the sites. The spatial variability of fish community structure was related to the benthic cover composition and depth. The high abundance of territorial herbivores and mobile invertebrate feeders could be associated with high levels of turf cover, low wave exposure and shallow waters. Moreover, this fact could be a consequence of the low density of roving herbivores and large carnivores probably due to the pressure of intense fishing activity. Thus complementary studies are needed to evaluate the actual conservation status of these rocky shore reefs, singularly located habitats connecting inner and outer reefs in Todos os Santos Bay.

  12. Effects of lower trophic level biomass and water temperature on fish communities: A modelling study

    Science.gov (United States)

    Guiet, Jérôme; Aumont, Olivier; Poggiale, Jean-Christophe; Maury, Olivier

    2016-08-01

    Physical and biogeochemical changes of the oceans have complex influences on fish communities. Variations of resource and temperature affect metabolic rates at the individual level, biomass fluxes at the species level, and trophic structure as well as diversity at the community level. We use a Dynamic Energy Budget-, trait-based model of the consumers' community size-spectrum to assess the effects of lower trophic level biomass and water temperature on communities at steady state. First, we look at the stressors separately in idealized simulations, varying one while the second remains constant. A multi-domain response is observed. Linked to the number of trophic levels sustained in the consumers' community, the regimes highlighted present similar properties when lower trophic level biomass is increased or temperature decreased. These trophic-length domains correspond to different efficiencies of the transfer of biomass from small to large individuals. They are characterized by different sensitivities of fish communities to environmental changes. Moreover, differences in the scaling of individuals' metabolism and prey assimilation with temperature lead to a shrinking of fish communities with warming. In a second step, we look at the impact of simultaneous variations of stressors along a mean latitudinal gradient of lower trophic level biomass and temperature. The model explains known observed features of global marine ecosystems such as the fact that larger species compose fish communities when latitude increases. The structure, diversity and metabolic properties of fish communities obtained with the model at different latitudes are interpreted in light of the different trophic-length domains characterized in the idealized experiments. From the equator to the poles, the structure of consumers' communities is predicted to be heterogeneous, with variable sensitivities to environmental changes.

  13. Evolution of kin recognition mechanisms in a fish.

    Science.gov (United States)

    Hain, Timothy J A; Garner, Shawn R; Ramnarine, Indar W; Neff, Bryan D

    2017-03-01

    Both selection and phylogenetic history can influence the evolution of phenotypic traits. Here we used recently characterized variation in kin recognition mechanisms among six guppy populations to explore the phylogenetic history of this trait. Guppies can use two different kin recognition mechanisms: either phenotype matching, in which individuals are identified based on comparison with a recognition template, or familiarity, in which individuals are remembered based on previous interactions. Across the six populations, we identified four transitions in recognition mechanism: phenotype matching evolved once and was subsequently lost in a single population, whereas familiarity evolved twice. Based on a molecular clock, these transitions occurred among populations that had diverged on a timescale of hundreds of thousands of years, which is two orders of magnitude faster than previously documented transitions in recognition mechanisms. A randomization test provided no evidence that recognition mechanisms were constrained by phylogeny, suggesting that recognition mechanisms have the capacity to evolve rapidly, although the specific selection pressures that may be contributing to variation in recognition mechanisms across populations remain unknown.

  14. Richness and diversity of helminth communities in tropical freshwater fishes: Empirical evidence

    Science.gov (United States)

    Choudhury, A.; Dick, T.A.

    2000-01-01

    Aim: Published information on the richness and diversity of helminth parasite communities in tropical freshwater fishes is reviewed in response to expectations of species-rich parasite communities in tropical regions. Location: Areas covered include the tropics and some subtropical areas. In addition, the north temperate area of the nearctic zone is included for comparison. Methods: Data from 159 communities in 118 species of tropical freshwater fish, summarized from 46 published studies, were used for this review. Parasite community descriptors used in the analyses included component community richness and calculated mean species richness. Data from 130 communities in 47 species of nearctic north temperate freshwater fish were summarized from 31 studies and used for comparison. Results: The component helminth communities of many tropical freshwater fish are species-poor, and considerable proportions of fish from certain parts of the tropics, e.g. West African drainages, are uninfected or lightly infected. Mean helminth species richness was low and equaled or exceeded 2.0 in only 22 of 114 communities. No single group of helminths was identified as a dominant component of the fauna and species composition was variable among and within broader geographical areas. The richest enteric helminth assemblages were found in mochokid and clariid catfish with a mixed carnivorous diet, whereas algal feeders, herbivores and detritivores generally had species-poor gut helminth communities. Comparisons indicated that certain areas in the north temperate region had higher helminth species richness in fishes than areas in the tropics. Main conclusions: Expectations of high species richness in helminth communities of tropical freshwater fishes are not fulfilled by the data. Direct comparisons of infracommunities and component communities in host species across widely separated phylogenetic and geographical lines are inappropriate. Examination of latitudinal differences in richness

  15. The structure and evolution of plankton communities

    Science.gov (United States)

    Longhurst, Alan R.

    New understanding of the circulation of ancient oceans is not yet matched by progress in our understanding of their pelagic ecology, though it was the planktonic ecosystems that generated our offshore oil and gas reserves. Can we assume that present-day models of ecosystem function are also valid for ancient seas? This question is addressed by a study of over 4000 plankton samples to derive a comprehensive, global description of zooplankton community structure in modern oceans: this shows that copepods form only 50% of the biomass of all plankton, ranging from 70% in polar to 35% in tropical seas. Comparable figures are derived from 14 other taxonomic categories of zooplankton. For trophic groupings, the data indicate globally: geletinous predators - 14%; gelatinous herbivores - 4%; raptorial predators - 33%; macrofiltering herbivores - 20%; macrofiltering omnivores - 25%; and detritivores - 3%. A simple, idealized model for the modern pelagic ecosystem is derived from these percentages which indicates that metazooplankton are not the most important consumers of pico- and nano-plankton production which itself probably constitutes 90% of primary production in warm oceans. This model is then compared with candidate life-forms available in Palaeozoic and Mesozoic oceans to determine to what extent it is also valid for ancient ecosystems: it is concluded that it is probably unnecessary to postulate models fundamentally differing from it in order to accommodate the life-forms, both protozoic and metazoic, known to have populated ancient seas. Remarkably few life-forms have existed which cannot be paralleled in the modern ocean, which contains remarkably few life-forms which cannot be paralleled in the Palaeozoic ocean. As a first assumption, then, it is reasonable to assume that energy pathways were similar in ancient oceans to those we study today.

  16. Responses of epibenthic and nektonic macroinvertebrate communities to a gradient of fish size in ponds

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    Marek Nieoczym

    2014-07-01

    Full Text Available Size relationships between fish and organisms from adjacent trophic levels are crucial for predicting the structure and dynamics of aquatic ecosystems. We compared macroinvertebrate communities along a fish-size gradient created by separate stocking of three age cohorts of common carp Cyprinus carpio in semi-natural ponds. The specific size range of fish (small, medium and large corresponding to fish age in ponds was the factor most strongly associated with macroinvertebrate composition. The other significant habitat variables were dissolved oxygen concentration in the water and submerged vegetation abundance in the open-water zone. Among the most numerous taxa in the ponds, relative abundances of Hirudinea, Gastropoda, Odonata and Coleoptera were larger in the presence of small-sized than of larger-sized carp. However, fish size effect was not linear, in that macroinvertebrate assemblages were less similar between ponds containing medium- vs large-sized fish than between ponds with small- vs large-sized fish. The dissimilarity patterns were mainly determined by disparities in abundance of Corixidae, which unlike other taxa common in the ponds occurred in the greatest numbers in the presence of large-sized carp. Macroinvertebrate diversity was greatest in ponds with small-sized fish and was positively related to emergent macrophyte cover. Enhancement of emergent vegetation is recommended as the most effective management strategy to buffer adverse impacts of fish on macroinvertebrates. If fish are present in the system, assessment of the size structure of fish populations can be advantageous in unravelling the essential processes driving the variation in pond communities.

  17. Structure of the scientific community modelling the evolution of resistance.

    Science.gov (United States)

    2007-12-05

    Faced with the recurrent evolution of resistance to pesticides and drugs, the scientific community has developed theoretical models aimed at identifying the main factors of this evolution and predicting the efficiency of resistance management strategies. The evolutionary forces considered by these models are generally similar for viruses, bacteria, fungi, plants or arthropods facing drugs or pesticides, so interaction between scientists working on different biological organisms would be expected. We tested this by analysing co-authorship and co-citation networks using a database of 187 articles published from 1977 to 2006 concerning models of resistance evolution to all major classes of pesticides and drugs. These analyses identified two main groups. One group, led by ecologists or agronomists, is interested in agricultural crop or stock pests and diseases. It mainly uses a population genetics approach to model the evolution of resistance to insecticidal proteins, insecticides, herbicides, antihelminthic drugs and miticides. By contrast, the other group, led by medical scientists, is interested in human parasites and mostly uses epidemiological models to study the evolution of resistance to antibiotic and antiviral drugs. Our analyses suggested that there is also a small scientific group focusing on resistance to antimalaria drugs, and which is only poorly connected with the two larger groups. The analysis of cited references indicates that each of the two large communities publishes its research in a different set of literature and has its own keystone references: citations with a large impact in one group are almost never cited by the other. We fear the lack of exchange between the two communities might slow progress concerning resistance evolution which is currently a major issue for society.

  18. Evolution of the branchiostegal membrane and restricted gill openings in Actinopterygian fishes.

    Science.gov (United States)

    Farina, Stacy C; Near, Thomas J; Bemis, William E

    2015-06-01

    A phylogenetic survey is a powerful approach for investigating the evolutionary history of a morphological characteristic that has evolved numerous times without obvious functional implications. Restricted gill openings, an extreme modification of the branchiostegal membrane, are an example of such a characteristic. We examine the evolution of branchiostegal membrane morphology and highlight convergent evolution of restricted gill openings. We surveyed specimens from 433 families of actinopterygians for branchiostegal membrane morphology and measured head and body dimensions. We inferred a relaxed molecular clock phylogeny with branch length estimates based on nine nuclear genes sampled from 285 species that include all major lineages of Actinopterygii. We calculated marginal state reconstructions of four branchiostegal membrane conditions and found that restricted gill openings have evolved independently in at least 11 major actinopterygian clades, and the total number of independent origins of the trait is likely much higher. A principal component analysis revealed that fishes with restricted gill openings occupy a larger morphospace, as defined by our linear measurements, than do fishes with nonrestricted openings. We used a decision tree analysis of ecological data to determine if restricted gill openings are linked to certain environments. We found that fishes with restricted gill openings repeatedly occur under a variety of ecological conditions, although they are rare in open-ocean pelagic environments. We also tested seven ratios for their utility in distinguishing between fishes with and without restricted gill openings, and we propose a simple metric for quantifying restricted gill openings (RGO), defined as a ratio of the distance from the ventral midline to the gill opening relative to half the circumference of the head. Functional explanations for this specialized morphology likely differ within each clade, but its repeated evolution indicates a need

  19. Body shape transformation along a shared axis of anatomical evolution in labyrinth fishes (Anabantoidei).

    Science.gov (United States)

    Collar, David C; Quintero, Michelle; Buttler, Bernardo; Ward, Andrea B; Mehta, Rita S

    2016-03-01

    Major morphological transformations, such as the evolution of elongate body shape in vertebrates, punctuate evolutionary history. A fundamental step in understanding the processes that give rise to such transformations is identification of the underlying anatomical changes. But as we demonstrate in this study, important insights can also be gained by comparing these changes to those that occur in ancestral and closely related lineages. In labyrinth fishes (Anabantoidei), rapid evolution of a highly derived torpedo-shaped body in the common ancestor of the pikehead (Luciocephalus aura and L. pulcher) occurred primarily through exceptional elongation of the head, with secondary contributions involving reduction in body depth and lengthening of the precaudal vertebral region. This combination of changes aligns closely with the primary axis of anatomical diversification in other anabantoids, revealing that pikehead evolution involved extraordinarily rapid change in structures that were ancestrally labile. Finer-scale examination of the anatomical components that determine head elongation also shows alignment between the pikehead evolutionary trajectory and the primary axis of cranial diversification in anabantoids, with much higher evolutionary rates leading to the pikehead. Altogether, our results show major morphological transformation stemming from extreme change along a shared morphological axis in labyrinth fishes. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  20. Molecular Evolution of Aralkylamine N-Acetyltransferase in Fish: A Genomic Survey

    Directory of Open Access Journals (Sweden)

    Jia Li

    2015-12-01

    Full Text Available All living organisms synchronize biological functions with environmental changes; melatonin plays a vital role in regulating daily and seasonal variations. Due to rhythmic activity of the timezyme aralkylamine N-acetyltransferase (AANAT, the blood level of melatonin increases at night and decreases during daytime. Whereas other vertebrates have a single form of AANAT, bony fishes possess various isoforms of aanat genes, though the reasons are still unclear. Here, we have taken advantage of multiple unpublished teleost aanat sequences to explore and expand our understanding of the molecular evolution of aanat in fish. Our results confirm that two rounds of whole-genome duplication (WGD led to the existence of three fish isoforms of aanat, i.e., aanat1a, aanat1b, and aanat2; in addition, gene loss led to the absence of some forms from certain special fish species. Furthermore, we suggest the different roles of two aanat1s in amphibious mudskippers, and speculate that the loss of aanat1a, may be related to terrestrial vision change. Several important sites of AANAT proteins and regulatory elements of aanat genes were analyzed for structural comparison and functional forecasting, respectively, which provides insights into the molecular evolution of the differences between AANAT1 and AANAT2.

  1. Evolution and origin of vomeronasal-type odorant receptor gene repertoire in fishes

    Directory of Open Access Journals (Sweden)

    Nishida Mutsumi

    2006-10-01

    Full Text Available Abstract Background In teleost fishes that lack a vomeronasal organ, both main odorant receptors (ORs and vomeronasal receptors family 2 (V2Rs are expressed in the olfactory epithelium, and used for perception of water-soluble chemicals. In zebrafish, it is known that both ORs and V2Rs formed multigene families of about a hundred copies. Whereas the contribution of V2Rs in zebrafish to olfaction has been found to be substantially large, the composition and structure of the V2R gene family in other fishes are poorly known, compared with the OR gene family. Results To understand the evolutionary dynamics of V2R genes in fishes, V2R sequences in zebrafish, medaka, fugu, and spotted green pufferfish were identified from their draft genome sequences. There were remarkable differences in the number of intact V2R genes in different species. Most V2R genes in these fishes were tightly clustered in one or two specific chromosomal regions. Phylogenetic analysis revealed that the fish V2R family could be subdivided into 16 subfamilies that had diverged before the separation of the four fishes. Genes in two subfamilies in zebrafish and another subfamily in medaka increased in their number independently, suggesting species-specific evolution in olfaction. Interestingly, the arrangements of V2R genes in the gene clusters were highly conserved among species in the subfamily level. A genomic region of tetrapods corresponding to the region in fishes that contains the V2R cluster was found to have no V2R gene in any species. Conclusion Our results have indicated that the evolutionary dynamics of fish V2Rs are characterized by rapid gene turnover and lineage-specific phylogenetic clustering. In addition, the present phylogenetic and comparative genome analyses have shown that the fish V2Rs have expanded after the divergence between teleost and tetrapod lineages. The present identification of the entire V2R repertoire in fishes would provide useful foundation to

  2. Restoration of a temperate reef: Effects on the fish community

    DEFF Research Database (Denmark)

    Støttrup, Josianne; Stenberg, Claus; Dahl, Karsten

    2014-01-01

    The extraction of large boulders from coastal reefs for construction of harbours and coastal protection has led to habitat degradation for local fish populations through the destruction of cavernous reefs and changes in macroalgal cover resulting from a loss of substrate. The temperate reef at Læ...

  3. Response of a temperate demersal fish community to global warming

    Science.gov (United States)

    Punzón, A.; Serrano, A.; Sánchez, F.; Velasco, F.; Preciado, I.; González-Irusta, J. M.; López-López, L.

    2016-09-01

    Changes in the distribution of the demersal fish species have been identified in north-European Atlantic waters. The consequence of these changes has been a northward shift of the distribution limits and changes in richness. In this study a notable increase in demersal fish species richness per sampling station was detected in the southern Bay of Biscay. This rise was due to an increase in frequency of occurrence and abundance of the majority of fish species in the area (53% from the total species). A fisheries relate explanation was discarded because the mismatch between the changes in the fishing effort and the augment in frequency of occurrence and abundance. On the contrary, these changes are in agreement with expected response under the increasing temperature of the sea observed over the last three decades, associated to global warming. These changes were positively correlated with an increase in temperature of intermediate waters in the study area. In addition, some of these species showed a notable western displacements of the Centre of Gravity in the study area, which would be expected if temperate water species would be favoured by an increase in water temperature. Our results are consistent with studies in the North Sea, where many of these species showing widened distribution limits towards north. The analysis of the results shows that the studied ecosystem, the Bay of Biscay is under a meridionalization process. On the other hand, only one tropicalization event (Lepidotrigla dieuzeidei), was recorded, maybe due to the conservative restrictions applied in species selection.

  4. Community Evolution in International Migration Top1 Networks.

    Science.gov (United States)

    Peres, Mihaela; Xu, Helian; Wu, Gang

    2016-01-01

    Focusing on each country's topmost destination/origin migration relation with other countries, this study builds top1 destination networks and top1 origin networks in order to understand their skeletal construction and community dynamics. Each top1 network covers approximately 50% of the complete migrant network stock for each decade between 1960 and 2000. We investigate the community structure by implementing the Girvan-Newman algorithm and compare the number of components and communities to illustrate their differences. We find that (i) both top1 networks (origin and destination) exhibited communities with a clear structure and a surprising evolution, although 80% edges persist between each decade; (ii) top1 destination networks focused on developed countries exhibiting shorter paths and preferring more advance countries, while top1 origin networks focused both on developed as well as more substantial developing nations that presented a longer path and more stable groups; (iii) only few countries have a decisive influence on community evolution of both top1 networks. USA took the leading position as a destination country in top1 destination networks, while China and India were the main Asian emigration countries in top1 origin networks; European countries and the Russian Federation played an important role in both.

  5. Community Evolution in International Migration Top1 Networks.

    Directory of Open Access Journals (Sweden)

    Mihaela Peres

    Full Text Available Focusing on each country's topmost destination/origin migration relation with other countries, this study builds top1 destination networks and top1 origin networks in order to understand their skeletal construction and community dynamics. Each top1 network covers approximately 50% of the complete migrant network stock for each decade between 1960 and 2000. We investigate the community structure by implementing the Girvan-Newman algorithm and compare the number of components and communities to illustrate their differences. We find that (i both top1 networks (origin and destination exhibited communities with a clear structure and a surprising evolution, although 80% edges persist between each decade; (ii top1 destination networks focused on developed countries exhibiting shorter paths and preferring more advance countries, while top1 origin networks focused both on developed as well as more substantial developing nations that presented a longer path and more stable groups; (iii only few countries have a decisive influence on community evolution of both top1 networks. USA took the leading position as a destination country in top1 destination networks, while China and India were the main Asian emigration countries in top1 origin networks; European countries and the Russian Federation played an important role in both.

  6. Does human pressure affect the community structure of surf zone fish in sandy beaches?

    Science.gov (United States)

    Costa, Leonardo Lopes; Landmann, Júlia G.; Gaelzer, Luiz R.; Zalmon, Ilana R.

    2017-01-01

    Intense tourism and human activities have resulted in habitat destruction in sandy beach ecosystems with negative impacts on the associated communities. To investigate whether urbanized beaches affect surf zone fish communities, fish and their benthic macrofaunal prey were collected during periods of low and high human pressure at two beaches on the Southeastern Brazilian coast. A BACI experimental design (Before-After-Control-Impact) was adapted for comparisons of tourism impact on fish community composition and structure in urbanized, intermediate and non-urbanized sectors of each beach. At the end of the summer season, we observed a significant reduction in fish richness, abundance, and diversity in the high tourist pressure areas. The negative association between visitors' abundance and the macrofaunal density suggests that urbanized beaches are avoided by surf zone fish due to higher human pressure and the reduction of food availability. Our results indicate that surf zone fish should be included in environmental impact studies in sandy beaches, including commercial species, e.g., the bluefish Pomatomus saltatrix. The comparative results from the less urbanized areas suggest that environmental zoning and visitation limits should be used as effective management and preservation strategies on beaches with high conservation potential.

  7. Functional diversity of fish communities in two tropical estuaries subjected to anthropogenic disturbance.

    Science.gov (United States)

    Dolbeth, M; Vendel, A L; Pessanha, A; Patrício, J

    2016-11-15

    The functional diversity of fish communities was studied along the salinity gradient of two estuaries in Northeast Brazil subjected to different anthropogenic pressures, to gain a better understanding of the response of fish communities to disturbance. We evaluated functional complementarity indices, redundancy and analysed functional composition through functional groups based on combinations of different traits. The fish communities in both estuaries share similar functions performed by few functional groups. The upstream areas had generally lower taxonomic, functional diversity and lower redundancy, suggesting greater vulnerability to impacts caused by human activities. Biomass was slightly more evenly distributed among functional groups in the less disturbed estuary, but total biomass and redundancy were lower in comparison to the urbanized estuary. The present findings lend strength to the notion that the less disturbed estuary may be more susceptible to anthropogenic impacts, underscoring the need for more effective conservation measures directed at this estuary.

  8. Habitat loss and gain: Influence on habitat attractiveness for estuarine fish communities

    Science.gov (United States)

    Amorim, Eva; Ramos, Sandra; Elliott, Michael; Franco, Anita; Bordalo, Adriano A.

    2017-10-01

    Habitat structure and complexity influence the structuring and functioning of fish communities. Habitat changes are one of the main pressures affecting estuarine systems worldwide, yet the degree and rate of change and its impact on fish communities is still poorly understood. In order to quantify historical modifications in habitat structure, an ecohydrological classification system using physiotopes, i.e. units with homogenous abiotic characteristics, was developed for the lower Lima estuary (NW Portugal). Field data, aerial imagery, historical maps and interpolation methods were used to map input variables, including bathymetry, substratum (hard/soft), sediment composition, hydrodynamics (current velocity) and vegetation coverage. Physiotopes were then mapped for the years of 1933 and 2013 and the areas lost and gained over the 80 years were quantified. The implications of changes for the benthic and demersal fish communities using the lower estuary were estimated using the attractiveness to those communities of each physiotope, while considering the main estuarine habitat functions for fish, namely spawning, nursery, feeding and refuge areas and migratory routes. The lower estuary was highly affected due to urbanisation and development and, following a port/harbour expansion, its boundary moved seaward causing an increase in total area. Modifications led to the loss of most of its sandy and saltmarsh intertidal physiotopes, which were replaced by deeper subtidal physiotopes. The most attractive physiotopes for fish (defined as the way in which they supported the fish ecological features) decreased in area while less attractive ones increased, producing an overall lower attractiveness of the studied area in 2013 compared to 1933. The implications of habitat alterations for the fish using the estuary include potential changes in the nursery carrying capacity and the functioning of the fish community. The study also highlighted the poor knowledge of the impacts of

  9. PCDD and PCDF exposures among fishing community through intake of fish and shellfish from the Straits of Malacca.

    Science.gov (United States)

    Azlan, Azrina; Nasir, Nurul Nadiah Mohamad; Shamsudin, Norashikin; Rahman, Hejar Abdul; Khoo, Hock Eng; Razman, Muhammad Rizal

    2015-07-21

    Exposure to PCDD/PCDF (dioxin and furan) through consumption of fish and shellfish is closely related to the occurrence of skin diseases, such as chloracne and hyperpigmentation. This study aimed to determine the exposure of PCDD/PCDF and its congeners in fish and shellfish obtained from different regions of the Straits of Malacca among the fishing community. The risk of fish and shellfish consumption and exposure to PCDD/PCDF among fishermen living in coastal areas of the Straits were evaluated based on a cross-sectional study involving face to face interviews, blood pressure and anthropometric measurements, and administration of food frequency questionnaires (FFQ). Skin examination was done by a dermatologist after the interview session. Determination of 17 congeners of PCDD/PCDF in 48 composite samples of fish and shellfish was performed based on HRGC/HRMS analysis. The total PCDD/PCDF in the seafood samples ranged from 0.12 to 1.24 pg WHO-TEQ/g fresh weight (4.6-21.8 pg WHO-TEQ/g fat). No significant difference found for the concentrations of PCDD/PCDF between the same types of seafood samples obtained from the three different regions. The concentrations of the most potent congener, 2,3,7,8-TCDD in the seafood samples ranged from 0.01 to 0.11 pg WHO-TEQ/g FW (1.9 pg WHO-TEQ/g fat). A positive moderate correlation was found between the fat contents and concentrations of PCDD/PCDF determined in the seafood samples. The total PCDD/PCDF in all seafood samples were below the 1 pg WHO-TEQ/g fresh weight, with the exception of grey eel-catfish. The respondents had consumed fish and shellfish with the amounts ranging between 2.02 g and 44.06 g per person per day. The total PCDD/PCDF exposures through consumption of fish and shellfish among the respondents were between 0.01 and 0.16 pg WHO-TEQ/kg BW/day. With regard to the two PCDD/PCDF-related skin diseases, no chloracne case was found among the respondents, but 2.2% of the respondents were diagnosed to have

  10. Composition of fish communities in an intertidal salt marsh creek in the Changjiang River estuary, China

    Institute of Scientific and Technical Information of China (English)

    QUAN Weimin; NI Yong; SHI Liyan; CHEN Yaqu

    2009-01-01

    Fish communities in a (third-order) intertidal creek in Dongtan marsh in the Changjiang (Yangtze) River estuary were investigated seasonally for one year. A total of 1 996 fish specimens (10 967.8 g) comprising 26 species and 15 families were collected. Abundances of fish communities in the intertidal salt marsh creek were primarily dominated by Boleophthalmus pectinirostris (19.8%), Collichthys lucidus (18.6%), Periophthalmus magnuspinnatus (18.2%), Liza haematocheilus (17.9%), and secondarily by Mugilogobius abei (8.5%), L. carinatus (7.2%), Odontamblyopus lacepedii (4.3%), and Acanthogobius ommaturus (3.9%); another 18 species were present only occasionally. Non-MDS ordination and SIMPER analysis indicated that there were two fish communities in the intertidal salt marsh creek. In spring, the communities were dominated by B. pectinirostris, P. magnuspinnatus, C. lucidus and M. abei; in summer, autumn, and winter by L. haematocheilus, L. carinatus, A. ommaturus and O. lacepedii. Some species showed strong habitat selection; L. carinatus and P. magnuspinnatus were distributed mainly in the upper and middle creek, while B. pectinirostris, M. abei and O. lacepedii inhabited the middle and lower creek. The study indicated that the salt marshes of the Changjiang River estuary are an important nursery and feeding habitat for many fishes and should be protected.

  11. Climate Change, Urbanization and Livelihood Perspective of Indigenous Fishing Communities of Mumbai, India

    Directory of Open Access Journals (Sweden)

    Senapati Sibananda

    2014-10-01

    Full Text Available This study is an attempt to derive the socio-economic implications of climate change and other environmental issues pertaining to fishing communities residing in and around Mumbai, India. A substantial number of populations in Mumbai city are the fishing communities, popularly known as ‘Koli’. They are the earliest inhabitants of the city. Coastal cities are most productive as well as most vulnerable to environmental changes. They support a number of economic activities which include fishing, agriculture, urbanization, real estate, tourism, transport, oil exploration etc. As a result, the anthropogenic pressure on coastal cities is increasing. Koli communities in Mumbai encounter diverse socio-economic and climatic pressures including sea level rise, floods, storms, etc. The implications of climate change on Koli communities as well as other environmental issues pertaining to fishing villages in Mumbai are discussed in detail in this study. Five fishing villages from Mumbai are selected for a primary study based on a structured questionnaire. Nearly 200 households are surveyed in a period over six months in 2011-12, finally 182 households information is considered for further analysis. On the basis of the findings, this study suggests that issue of lack of asset formation and financial insecurity among young fishermen may be taken care by linking the fisheries societies in Mumbai and in other regions with the support from local governments. The benefits of subsidies, insurance may be distributed progressively based on their financial needs to all fishermen rather than benefiting the large scale fishermen alone.

  12. Seascape context and predators override water quality effects on inshore coral reef fish communities

    Science.gov (United States)

    Gilby, Ben L.; Tibbetts, Ian R.; Olds, Andrew D.; Maxwell, Paul S.; Stevens, Tim

    2016-09-01

    Understanding the relative influence of factors that influence faunal community structure, such as habitat and landscape arrangement, has been a long-standing goal of ecologists. This is complicated in marine environments by the high importance of physico-chemical water factors in determining species distributions relative to their physiological or behavioural limits. In this study, we rank the relative importance of 17 seascape, habitat and physico-chemical water factors for structuring the composition of fish communities on the inshore coral reefs of Moreton Bay, eastern Australia. Fish were surveyed at 12 reef sites along the ambient estuarine water gradient in the bay during summer and winter using a baited underwater video approach. Multivariate random forest analyses showed that reef fish community composition correlated most strongly with the local abundance of piscivorous fish and the seascape context of individual reefs (especially distance to nearest seagrass and mangroves), while water quality factors ranked much lower in importance. However, fish communities from sites nearer to rivers were more spatiotemporally variable than those from sites nearer to oceanic waters, indicating that water quality can drive variations in community structure along short-term temporal scales. In turn, piscivore abundance was greatest on reefs near large areas of seagrass, and with low sand cover, high coral cover and high water clarity. Our findings demonstrate that a reef's location within the broader seascape can be more important for fish communities than factors relating to the reef habitat itself and exposure to reduced water quality. To improve the spatial conservation of marine ecosystems, we encourage a more intimate understanding of how these factors contribute to structuring the use of habitats across seascapes by mobile species.

  13. Long-term comparison of the fish community in a Costa Rican rocky shore marine reserve.

    Science.gov (United States)

    Myers, Mark C; Wagner, Jonathan; Vaughan, Christopher

    2011-03-01

    Despite their role in supporting diverse marine fish communities, tropical rocky shores and reefs have attracted less research and fewer targeted conservation efforts compared to coral reefs. We studied fish community composition in Playa Blanca Marine Reserve (9 degrees 40' N - 84 degrees 40' W), a rocky shore site on the central Pacific coast of Costa Rica. We conducted visual surveys of fishes along six strip transects soon after the area was designated a marine reserve in 1995, then again in 2006 following an eleven-year period of complete protection. We recorded a total of 31 406 sightings of 72 species from 30 families. Pomacentrids (42.5%), labrids (16.6%) and haemulids (14.8%) dominated the community, accounting for > 70% of total fish abundance. In comparison to other sites in the region, the fish community was more similar to one reported from Bahia Honda, Panama (7 degrees 50' N - 81 degrees 35 W) than from the geographically more proximate Culebra Bay, Costa Rica (10 degrees 45' N - 85 degrees 43 W). Sixty-one species from 26 families were recorded in 1995; sixty-nine species from 28 families in 2006. Our results suggest that the Playa Blanca Marine Reserve is fulfilling its conservation role. Average fish abundance, species richness and Shannon's index of community diversity were greater in 2006 than 1995, and fish community composition varied significantly within each transect among years. Much of the change in community composition among years resulted from spatial and temporal variation in the abundance of a few dominant species, including Abudefduf troschelli, Thalassoma lucasanum, Chromis atrilobata, and Stegastes flavilatus/acapulcoensis. Of the 48 species/species groups recorded in both years, 37 (77%) were more abundant in 2006 than 1995, and several species recorded as uncommon or rare in 1995 were more frequent and abundant in 2006. Fish community composition and the abundance of some species changed in the reserve over time, but further

  14. Spatial patterns of fish communities along two estuarine gradients in southern Florida

    Science.gov (United States)

    Green, D.P.J.; Trexler, J.C.; Lorenz, J.J.; McIvor, C.C.; Philippi, T.

    2006-01-01

    In tropical and subtropical estuaries, gradients of primary productivity and salinity are generally invoked to explain patterns in community structure and standing crops of fishes. We documented spatial and temporal patterns in fish community structure and standing crops along salinity and nutrient gradients in two subtropical drainages of Everglades National Park, USA. The Shark River drains into the Gulf of Mexico and experiences diurnal tides carrying relatively nutrient enriched waters, while Taylor River is more hydrologically isolated by the oligohaline Florida Bay and experiences no discernable lunar tides. We hypothesized that the more nutrient enriched system would support higher standing crops of fishes in its mangrove zone. We collected 50 species of fish from January 2000 to April 2004 at six sampling sites spanning fresh to brackish salinities in both the Shark and Taylor River drainages. Contrary to expectations, we observed lower standing crops and density of fishes in the more nutrient rich tidal mangrove forest of the Shark River than in the less nutrient rich mangrove habitats bordering the Taylor River. Tidal mangrove habitats in the Shark River were dominated by salt-tolerant fish and displayed lower species richness than mangrove communities in the Taylor River, which included more freshwater taxa and yielded relatively higher richness. These differences were maintained even after controlling for salinity at the time of sampling. Small-scale topographic relief differs between these two systems, possibly created by tidal action in the Shark River. We propose that this difference in topography limits movement of fishes from upstream marshes into the fringing mangrove forest in the Shark River system, but not the Taylor River system. Understanding the influence of habitat structure, including connectivity, on aquatic communities is important to anticipate effects of construction and operational alternatives associated with restoration of the

  15. Fish communities associated with cold-water corals vary with depth and substratum type

    Science.gov (United States)

    Milligan, Rosanna J.; Spence, Gemma; Roberts, J. Murray; Bailey, David M.

    2016-08-01

    Understanding the processes that drive the distribution patterns of organisms and the scales over which these processes operate are vital when considering the effective management of species with high commercial or conservation value. In the deep sea, the importance of scleractinian cold-water corals (CWCs) to fish has been the focus of several studies but their role remains unclear. We propose this may be due to the confounding effects of multiple drivers operating over multiple spatial scales. The aims of this study were to investigate the role of CWCs in shaping fish community structure and individual species-habitat associations across four spatial scales in the NE Atlantic ranging from "regions" (separated by >500 km) to "substratum types" (contiguous). Demersal fish and substratum types were quantified from three regions: Logachev Mounds, Rockall Bank and Hebrides Terrace Seamount (HTS). PERMANOVA analyses showed significant differences in community composition between all regions which were most likely caused by differences in depths. Within regions, significant variation in community composition was recorded at scales of c. 20-3500 m. CWCs supported significantly different fish communities to non-CWC substrata at Rockall Bank, Logachev and the HTS. Single-species analyses using generalised linear mixed models showed that Sebastes sp. was strongly associated with CWCs at Rockall Bank and that Neocyttus helgae was more likely to occur in CWCs at the HTS. Depth had a significant effect on several other fish species. The results of this study suggest that the importance of CWCs to fish is species-specific and depends on the broader spatial context in which the substratum is found. The precautionary approach would be to assume that CWCs are important for associated fish, but must acknowledge that CWCs in different depths will not provide redundancy or replication within spatially-managed conservation networks.

  16. Biogeographic Patterns of Reef Fish Communities in the Saudi Arabian Red Sea

    KAUST Repository

    Roberts, May B.

    2014-12-01

    As a region renowned for high biodiversity, endemism and extreme temperature and salinity levels, the Red Sea is of high ecological interest. Despite this, there is relatively little literature on basic broad scale characteristics of the biodiversity or overall reef fish communities and how they change across latitude. We conducted visual transects recording the abundance of over 200 species of fish from 45 reefs spanning over 1000 km of Saudi Arabian coastline and used hierarchical cluster analysis to find that for combined depths from 0m-10m across this geographical range, the reef fish communities are relatively similar. However we find some interesting patterns both at the community level across depth and latitude as well as in endemic community distributions. We find that the communities, much like the environmental factors, shift gradually along latitude but do not show distinct clusters within the range we surveyed (from Al-Wajh in the north to the Farasan Banks in the south). Numbers of endemic species tend to be higher in the Thuwal region and further south. This type of baseline data on reef fish distribution and possible factors that may influence their ranges in the Red Sea are critical for future scientific studies as well as effective monitoring and in the face of the persistent anthropogenic influences such as coastal development, overfishing and climate change.

  17. Is there artisanal fishing territoriality in the Ubatumirim Bay (Ubatuba, SP? Scale issues in community relations

    Directory of Open Access Journals (Sweden)

    Cristiana Simão Seixas

    2008-03-01

    Full Text Available Scale issues are fundamental in the analysis of temporal and institutional dimensions of fishing territory. To understand actions and decisions at local and regional levels regarding fishing activity, we studied fishing communities at the Ubatumirim Bay, giving particular attention to the Almada community – north coast of the state of São Paulo. Data were collected between 2004 and 2005, a period in which artisanal fishers, officials and representatives of non-governmental organizations were interviewed. The results indicate the absence of territoriality at local level (within the community, but it exists implicitly at regional level (between communities. Both intercommunity relationships and fishing in areas outside the communities contributed to the building of a perception among fishers that “the sea belongs to everyone”. However, such perception that the sea is public does not imply the kind of free access that is unbound by rules. On the contrary, a large number of fishers believe that is important to have some mechanisms of control, and this must be agreed upon by officials and grassroots organizations within a horizontal institutional arrangement, i.e., all the stakeholders must have equal rights to vote and to make decisions.

  18. Assessing historical fish community composition using surveys, historical collection data, and species distribution models.

    Directory of Open Access Journals (Sweden)

    Ben Labay

    Full Text Available Accurate establishment of baseline conditions is critical to successful management and habitat restoration. We demonstrate the ability to robustly estimate historical fish community composition and assess the current status of the urbanized Barton Creek watershed in central Texas, U.S.A. Fish species were surveyed in 2008 and the resulting data compared to three sources of fish occurrence information: (i historical records from a museum specimen database and literature searches; (ii a nearly identical survey conducted 15 years earlier; and (iii a modeled historical community constructed with species distribution models (SDMs. This holistic approach, and especially the application of SDMs, allowed us to discover that the fish community in Barton Creek was more diverse than the historical data and survey methods alone indicated. Sixteen native species with high modeled probability of occurrence within the watershed were not found in the 2008 survey, seven of these were not found in either survey or in any of the historical collection records. Our approach allowed us to more rigorously establish the true baseline for the pre-development fish fauna and then to more accurately assess trends and develop hypotheses regarding factors driving current fish community composition to better inform management decisions and future restoration efforts. Smaller, urbanized freshwater systems, like Barton Creek, typically have a relatively poor historical biodiversity inventory coupled with long histories of alteration, and thus there is a propensity for land managers and researchers to apply inaccurate baseline standards. Our methods provide a way around that limitation by using SDMs derived from larger and richer biodiversity databases of a broader geographic scope. Broadly applied, we propose that this technique has potential to overcome limitations of popular bioassessment metrics (e.g., IBI to become a versatile and robust management tool for determining

  19. Boys Go Fishing, Girls Work at Home: Gender Roles, Poverty and Unequal School Access among Semi-Nomadic Fishing Communities in South Western Madagascar

    Science.gov (United States)

    Nascimento Moreira, Catarina; Rabenevanana, Man Wai; Picard, David

    2017-01-01

    Drawing from data gathered in South Western Madagascar in 2011, the work explores the combination of poverty and traditional gender roles as a critical factor in determining unequal school access among young people from semi-nomadic fishing communities. It demonstrates that from the age of early puberty, most boys go fishing with their fathers and…

  20. Evolution of estrogen receptors in ray-finned fish and their comparative responses to estrogenic substances.

    Science.gov (United States)

    Tohyama, Saki; Miyagawa, Shinichi; Lange, Anke; Ogino, Yukiko; Mizutani, Takeshi; Ihara, Masaru; Tanaka, Hiroaki; Tatarazako, Norihisa; Kobayashi, Tohru; Tyler, Charles R; Iguchi, Taisen

    2016-04-01

    In vertebrates, estrogens play fundamental roles in regulating reproductive activities through estrogen receptors (ESRs), and disruption of estrogen signaling is now of global concern for both wildlife and human health. To date, ESRs of only a limited number of species have been characterized. We investigated the functional diversity and molecular basis or ligand sensitivity of ESRs among ray-finned fish species (Actinopterygii), the most variable group within vertebrates. We cloned and characterized ESRs from several key species in the evolution of ray-finned fish including bichir (Polypteriformes, ESR1 and ESR2) at the basal lineage of ray-finned fish, and arowana (Osteoglossiformes, ESR1 and ESR2b) and eel (Anguilliformes, ESR1, ESR2a and ESR2b) both belonging to ancient early-branching lineages of teleosts, and suggest that ESR2a and ESR2b emerged through teleost-specific whole genome duplication, but an ESR1 paralogue has been lost in the early lineage of euteleost fish species. All cloned ESR isoforms showed similar responses to endogenous and synthetic steroidal estrogens, but they responded differently to non-steroidal estrogenic endocrine disrupting chemicals (EDCs) (e.g., ESR2a exhibits a weaker reporter activity compared with ESR2b). We show that variation in ligand sensitivity of ESRs can be attributed to phylogeny among species of different taxonomic groups in ray-finned fish. The molecular information provided contributes both to understanding of the comparative role of ESRs in the reproductive biology of fish and their comparative responses to EDCs.

  1. Evolution of the duplicated intracellular lipid-binding protein genes of teleost fishes.

    Science.gov (United States)

    Venkatachalam, Ananda B; Parmar, Manoj B; Wright, Jonathan M

    2017-08-01

    Increasing organismal complexity during the evolution of life has been attributed to the duplication of genes and entire genomes. More recently, theoretical models have been proposed that postulate the fate of duplicated genes, among them the duplication-degeneration-complementation (DDC) model. In the DDC model, the common fate of a duplicated gene is lost from the genome owing to nonfunctionalization. Duplicated genes are retained in the genome either by subfunctionalization, where the functions of the ancestral gene are sub-divided between the sister duplicate genes, or by neofunctionalization, where one of the duplicate genes acquires a new function. Both processes occur either by loss or gain of regulatory elements in the promoters of duplicated genes. Here, we review the genomic organization, evolution, and transcriptional regulation of the multigene family of intracellular lipid-binding protein (iLBP) genes from teleost fishes. Teleost fishes possess many copies of iLBP genes owing to a whole genome duplication (WGD) early in the teleost fish radiation. Moreover, the retention of duplicated iLBP genes is substantially higher than the retention of all other genes duplicated in the teleost genome. The fatty acid-binding protein genes, a subfamily of the iLBP multigene family in zebrafish, are differentially regulated by peroxisome proliferator-activated receptor (PPAR) isoforms, which may account for the retention of iLBP genes in the zebrafish genome by the process of subfunctionalization of cis-acting regulatory elements in iLBP gene promoters.

  2. Characterization of water quality and biological communities, Fish Creek, Teton County, Wyoming, 2007-2011

    Science.gov (United States)

    Eddy-Miller, Cheryl A.; Peterson, David A.; Wheeler, Jerrod D.; Edmiston, C. Scott; Taylor, Michelle L.; Leemon, Daniel J.

    2013-01-01

    Fish Creek, an approximately 25-kilometer-long tributary to Snake River, is located in Teton County in western Wyoming near the town of Wilson. Fish Creek is an important water body because it is used for irrigation, fishing, and recreation and adds scenic value to the Jackson Hole properties it runs through. Public concern about nuisance growths of aquatic plants in Fish Creek has been increasing since the early 2000s. To address these concerns, the U.S. Geological Survey conducted a study in cooperation with the Teton Conservation District to characterize the hydrology, water quality, and biologic communities of Fish Creek during 2007–11. The hydrology of Fish Creek is strongly affected by groundwater contributions from the area known as the Snake River west bank, which lies east of Fish Creek and west of Snake River. Because of this continuous groundwater discharge to the creek, land-use activities in the west bank area can affect the groundwater quality. Evaluation of nitrate isotopes and dissolved-nitrate concentrations in groundwater during the study indicated that nitrate was entering Fish Creek from groundwater, and that the source of nitrate was commonly a septic/sewage effluent or manure source, or multiple sources, potentially including artificial nitrogen fertilizers, natural soil organic matter, and mixtures of sources. Concentrations of dissolved nitrate and orthophosphate, which are key nutrients for growth of aquatic plants, generally were low in Fish Creek and occasionally were less than reporting levels (not detected). One potential reason for the low nutrient concentrations is that nutrients were being consumed by aquatic plant life that increases during the summer growing season, as a result of the seasonal increase in temperature and larger number of daylight hours. Several aspects of Fish Creek’s hydrology contribute to higher productivity and biovolume of aquatic plants in Fish Creek than typically observed in streams of its size in

  3. Trophic structure of a coastal fish community determined with diet and stable isotope analyses.

    Science.gov (United States)

    Malek, A J; Collie, J S; Taylor, D L

    2016-09-01

    A combination of dietary guild analysis and nitrogen (δ(15) N) and carbon (δ(13) C) stable-isotope analysis was used to assess the trophic structure of the fish community in Rhode Island and Block Island Sounds, an area off southern New England identified for offshore wind energy development. In the autumn of 2009, 2010 and 2011, stomach and tissue samples were taken from 20 fish and invertebrate species for analysis of diet composition and δ(15) N and δ(13) C signatures. The food chain in Rhode Island and Block Island Sounds comprises approximately four trophic levels within which the fish community is divided into distinct dietary guilds, including planktivores, benthivores, crustacivores and piscivores. Within these guilds, inter-species isotopic and dietary overlap is high, suggesting that resource partitioning or competitive interactions play a major role in structuring the fish community. Carbon isotopes indicate that most fishes are supported by pelagic phytoplankton, although there is evidence that benthic production also plays a role, particularly for obligate benthivores such as skates Leucoraja spp. This type of analysis is useful for developing an ecosystem-based approach to management, as it identifies species that act as direct links to basal resources as well as species groups that share trophic roles.

  4. A hierarchical community occurrence model for North Carolina stream fish

    Science.gov (United States)

    Midway, S.R.; Wagner, Tyler; Tracy, B.H.

    2016-01-01

    The southeastern USA is home to one of the richest—and most imperiled and threatened—freshwater fish assemblages in North America. For many of these rare and threatened species, conservation efforts are often limited by a lack of data. Drawing on a unique and extensive data set spanning over 20 years, we modeled occurrence probabilities of 126 stream fish species sampled throughout North Carolina, many of which occur more broadly in the southeastern USA. Specifically, we developed species-specific occurrence probabilities from hierarchical Bayesian multispecies models that were based on common land use and land cover covariates. We also used index of biotic integrity tolerance classifications as a second level in the model hierarchy; we identify this level as informative for our work, but it is flexible for future model applications. Based on the partial-pooling property of the models, we were able to generate occurrence probabilities for many imperiled and data-poor species in addition to highlighting a considerable amount of occurrence heterogeneity that supports species-specific investigations whenever possible. Our results provide critical species-level information on many threatened and imperiled species as well as information that may assist with re-evaluation of existing management strategies, such as the use of surrogate species. Finally, we highlight the use of a relatively simple hierarchical model that can easily be generalized for similar situations in which conventional models fail to provide reliable estimates for data-poor groups.

  5. Prey-Capture Strategies of Fish-Hunting Cone Snails: Behavior, Neurobiology and Evolution.

    Science.gov (United States)

    Olivera, Baldomero M; Seger, Jon; Horvath, Martin P; Fedosov, Alexander E

    2015-09-01

    The venomous fish-hunting cone snails (Conus) comprise eight distinct lineages evolved from ancestors that preyed on worms. In this article, we attempt to reconstruct events resulting in this shift in food resource by closely examining patterns of behavior, biochemical agents (toxins) that facilitate prey capture and the combinations of toxins present in extant species. The first sections introduce three different hunting behaviors associated with piscivory: 'taser-and-tether', 'net-engulfment' and 'strike-and-stalk'. The first two fish-hunting behaviors are clearly associated with distinct groups of venom components, called cabals, which act in concert to modify the behavior of prey in a specific manner. Derived fish-hunting behavior clearly also correlates with physical features of the radular tooth, the device that injects these biochemical components. Mapping behavior, biochemical components and radular tooth features onto phylogenetic trees shows that fish-hunting behavior emerged at least twice during evolution. The system presented here may be one of the best examples where diversity in structure, physiology and molecular features were initially driven by particular pathways selected through behavior.

  6. Estuarine fish communities respond to climate variability over both river and ocean basins

    Science.gov (United States)

    Feyrer, Frederick V.; Cloern, James E.; Brown, Larry R.; Fish, Maxfield; Hieb, Kathryn; Baxter, Randall

    2015-01-01

    Estuaries are dynamic environments at the land–sea interface that are strongly affected by interannual climate variability. Ocean–atmosphere processes propagate into estuaries from the sea, and atmospheric processes over land propagate into estuaries from watersheds. We examined the effects of these two separate climate-driven processes on pelagic and demersal fish community structure along the salinity gradient in the San Francisco Estuary, California, USA. A 33-year data set (1980–2012) on pelagic and demersal fishes spanning the freshwater to marine regions of the estuary suggested the existence of five estuarine salinity fish guilds: limnetic (salinity = 0–1), oligohaline (salinity = 1–12), mesohaline (salinity = 6–19), polyhaline (salinity = 19–28), and euhaline (salinity = 29–32). Climatic effects propagating from the adjacent Pacific Ocean, indexed by the North Pacific Gyre Oscillation (NPGO), affected demersal and pelagic fish community structure in the euhaline and polyhaline guilds. Climatic effects propagating over land, indexed as freshwater outflow from the watershed (OUT), affected demersal and pelagic fish community structure in the oligohaline, mesohaline, polyhaline, and euhaline guilds. The effects of OUT propagated further down the estuary salinity gradient than the effects of NPGO that propagated up the estuary salinity gradient, exemplifying the role of variable freshwater outflow as an important driver of biotic communities in river-dominated estuaries. These results illustrate how unique sources of climate variability interact to drive biotic communities and, therefore, that climate change is likely to be an important driver in shaping the future trajectory of biotic communities in estuaries and other transitional habitats.

  7. Fish communities of fixed sites in the Western Lake Michigan Drainages, Wisconsin and Michigan, 1993-95

    Science.gov (United States)

    Sullivan, D.J.

    1997-01-01

    Fish communities were surveyed at 20 wadable stream sites during 1993-95 as part of the U.S. Geological Survey's (USGS) National Water- Quality Assessment (NAWQA) Program's assessment of the Western Lake Michigan Drainages. Part of the NAWQA design is to incorporate ecological data into an overall environmental assessment. Collection of fish-community data was part of this ecological assessment.

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

    Science.gov (United States)

    Petersen, Carolyn

    2007-01-01

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

  9. Brain structure evolution in a basal vertebrate clade: evidence from phylogenetic comparative analysis of cichlid fishes

    Directory of Open Access Journals (Sweden)

    Kolm Niclas

    2009-09-01

    Full Text Available Abstract Background The vertebrate brain is composed of several interconnected, functionally distinct structures and much debate has surrounded the basic question of how these structures evolve. On the one hand, according to the 'mosaic evolution hypothesis', because of the elevated metabolic cost of brain tissue, selection is expected to target specific structures mediating the cognitive abilities which are being favored. On the other hand, the 'concerted evolution hypothesis' argues that developmental constraints limit such mosaic evolution and instead the size of the entire brain varies in response to selection on any of its constituent parts. To date, analyses of these hypotheses of brain evolution have been limited to mammals and birds; excluding Actinopterygii, the basal and most diverse class of vertebrates. Using a combination of recently developed phylogenetic multivariate allometry analyses and comparative methods that can identify distinct rates of evolution, even in highly correlated traits, we studied brain structure evolution in a highly variable clade of ray-finned fishes; the Tanganyikan cichlids. Results Total brain size explained 86% of the variance in brain structure volume in cichlids, a lower proportion than what has previously been reported for mammals. Brain structures showed variation in pair-wise allometry suggesting some degree of independence in evolutionary changes in size. This result is supported by variation among structures on the strength of their loadings on the principal size axis of the allometric analysis. The rate of evolution analyses generally supported the results of the multivariate allometry analyses, showing variation among several structures in their evolutionary patterns. The olfactory bulbs and hypothalamus were found to evolve faster than other structures while the dorsal medulla presented the slowest evolutionary rate. Conclusion Our results favor a mosaic model of brain evolution, as certain

  10. The Evolution of Community Structure in a Coauthorship Network

    Directory of Open Access Journals (Sweden)

    William Mcdowell

    2011-12-01

    Full Text Available Mechanisms such as triadic closure and preferential attachment drive the evolution of social networks. Many models use these mechanisms to predict future links, and they generate realistic networks with scale-free degree distributions. These social networks also have community structure, or sets of vertices which are more connected to each other than the rest of the network. To study the evolution of research groups of scientists in a coauthorship network, we use a timeheterarchy representation to extend the mechanisms driving the evolution of the network to the level of this community structure. Specifically, we examine changes in the structure of groups in terms of mechanisms analogous to triadic closure and preferential attachment, and as a result, we find that the network evolves in the same way at the group-level and the individual-level. In addition, we find that interactions at the group-level might affect interactions at the individual-level in that members of a single group are more likely to strengthen their relationships than members of separate groups.

  11. Seasonal Patterns in the Fish and Crustacean Community of a Turbid Temperate Estuary (Zeeschelde Estuary, Belgium)

    Science.gov (United States)

    Maes, J.; Taillieu, A.; Van Damme, P. A.; Cottenie, K.; Ollevier, F.

    1998-08-01

    Fish and crustaceans were sampled for 1 year in the upper reaches of a temperate estuary characterized by high turbidity and a tidal range of up to 5 m. Samples were taken in the cooling-water circuit of the Doel Nuclear Power station (Zeeschelde, Belgium). Between July 1994 and June 1995, 55 fish species, two shrimp species and four crab species were recorded. The fish community was composed of 36 marine species, 16 freshwater species and three diadromous species. Shrimps, Gobiidae and Clupeidae dominated the samples both in numbers and biomass. An exceptionally clear seasonal succession was observed in the species composition. It is argued that young fish and crustaceans use the highly turbid Zeeschelde Estuary as a refuge from predators.

  12. Spatial memory and hippocampal pallium through vertebrate evolution: insights from reptiles and teleost fish.

    Science.gov (United States)

    Rodríguez, F; López, J C; Vargas, J P; Broglio, C; Gómez, Y; Salas, C

    The forebrain of vertebrates shows great morphological variation and specialized adaptations. However, an increasing amount of neuroanatomical and functional data reveal that the evolution of the vertebrate forebrain could have been more conservative than previously realized. For example, the pallial region of the teleost telencephalon contains subdivisions presumably homologous with various pallial areas in amniotes, including possibly a homologue of the medial pallium or hippocampus. In mammals and birds, the hippocampus is critical for encoding complex spatial information to form map-like cognitive representations of the environment. Here, we present data showing that the pallial areas of reptiles and fish, previously proposed as homologous to the hippocampus of mammals and birds on an anatomical basis, are similarly involved in spatial memory and navigation by map-like or relational representations of the allocentric space. These data suggest that early in vertebrate evolution, the medial pallium of an ancestral fish group that gave rise to the extant vertebrates became specialized for processing and encoding complex spatial information, and that this functional trait has been retained through the evolution of each independent vertebrate lineage.

  13. The paradox of inverted biomass pyramids in kelp forest fish communities.

    Science.gov (United States)

    Trebilco, Rowan; Dulvy, Nicholas K; Anderson, Sean C; Salomon, Anne K

    2016-06-29

    Theory predicts that bottom-heavy biomass pyramids or 'stacks' should predominate in real-world communities if trophic-level increases with body size (mean predator-to-prey mass ratio (PPMR) more than 1). However, recent research suggests that inverted biomass pyramids (IBPs) characterize relatively pristine reef fish communities. Here, we estimated the slope of a kelp forest fish community biomass spectrum from underwater visual surveys. The observed biomass spectrum slope is strongly positive, reflecting an IBP. This is incongruous with theory because this steep positive slope would only be expected if trophic position decreased with increasing body size (consumer-to-resource mass ratio, less than 1). We then used δ(15)N signatures of fish muscle tissue to quantify the relationship between trophic position and body size and instead detected strong evidence for the opposite, with PPMR ≈ 1650 (50% credible interval 280-12 000). The natural history of kelp forest reef fishes suggests that this paradox could arise from energetic subsidies in the form of movement of mobile consumers across habitats, and from seasonally pulsed production inputs at small body sizes. There were four to five times more biomass at large body sizes (1-2 kg) than would be expected in a closed steady-state community providing a measure of the magnitude of subsidies.

  14. Coexistence in North Sea fish communities: implications for growth and natural mortality

    NARCIS (Netherlands)

    Gislason, H.; Pope, J.G.; Rice, J.C.; Daan, N.

    2008-01-01

    For a fish community to persist over time, all species must be able on average to replace themselves on a one-for-one basis over their lifetime. We use this principle and a size-based equilibrium model where asymptotic length is used as a functional trait to investigate how natural mortality should

  15. The use of Fish Community Structure as a Measure of Ecological ...

    African Journals Online (AJOL)

    The use of Fish Community Structure as a Measure of Ecological Degradation: A Case Study in Two Tropical Rivers of India. ... S K Das, D Chakrabarty ... tropical rivers of West Bengal, an eastern province of India, were studied for 2 annual ... Faso (3); Cameroon (8); Congo, Republic (1); Côte d'Ivoire (4); Egypt, Arab Rep.

  16. Relationships between community structure of freshwater mussels and host fishes in a central Ohio watershed

    Science.gov (United States)

    The diversity of freshwater mussel communities has declined over the past several decades within watersheds in the Midwestern United States. Host fishes play an important role in the life cycle of freshwater mussels because they serve as hosts for parasitic mussel larvae to ensure successful mussel ...

  17. Fish communities across a spectrum of habitats in the western Beaufort Sea and Chukchi Sea

    Science.gov (United States)

    Logerwell, E.; Busby, M.; Carothers, C.; Cotton, S.; Duffy-Anderson, J.; Farley, E.; Goddard, P.; Heintz, R.; Holladay, B.; Horne, J.; Johnson, S.; Lauth, B.; Moulton, L.; Neff, D.; Norcross, B.; Parker-Stetter, S.; Seigle, J.; Sformo, T.

    2015-08-01

    The increased scientific interest in the Arctic due to climate change and potential oil and gas development has resulted in numerous surveys of Arctic marine fish communities since the mid-2000s. Surveys have been conducted in nearly all Arctic marine fish habitats: from lagoons, beaches and across the continental shelf and slope. This provides an opportunity only recently available to study Arctic fish communities across a spectrum of habitats. We examined fish survey data from lagoon, beach, nearshore benthic, shelf pelagic and shelf benthic habitats in the western Beaufort Sea and Chukchi Sea. Specifically, we compare and contrast relative fish abundance and length (a proxy for age) among habitats and seas. We also examined ichthyoplankton presence/absence and abundance of dominant taxa in the shelf habitat. Our synthesis revealed more similarities than differences between the two seas. For example, our results show that the nearshore habitat is utilized by forage fish across age classes, and is also a nursery area for other species. Our results also indicated that some species may be expanding their range to the north, for example, Chinook Salmon. In addition, we documented the presence of commercially important taxa such as Walleye Pollock and flatfishes (Pleuronectidae). Our synthesis of information on relative abundance and age allowed us to propose detailed conceptual models for the life history distribution of key gadids in Arctic food webs: Arctic and Saffron Cod. Finally, we identify research gaps, such as the need for surveys of the surface waters of the Beaufort Sea, surveys of the lagoons of the Chukchi Sea, and winter season surveys in all areas. We recommend field studies on fish life history that sample multiple age classes in multiple habitats throughout the year to confirm, resolve and interpret the patterns in fish habitat use that we observed.

  18. Contrasting changes in taxonomic vs. functional diversity of tropical fish communities after habitat degradation.

    Science.gov (United States)

    Villéger, Sébastien; Ramos Miranda, Julia; Flores Hernández, Domingo; Mouillot, David

    2010-09-01

    Human activities have strong impacts on ecosystem functioning through their effect on abiotic factors and on biodiversity. There is also growing evidence that species functional traits link changes in species composition and shifts in ecosystem processes. Hence, it appears to be of utmost importance to quantify modifications in the functional structure of species communities after human disturbance in addition to changes in taxonomic structure. Despite this fact, there is still little consensus on the actual impacts of human-mediated habitat alteration on the components of biodiversity, which include species functional traits. Therefore, we studied changes in taxonomic diversity (richness and evenness), in functional diversity, and in functional specialization of estuarine fish communities facing drastic environmental and habitat alterations. The Terminos Lagoon (Gulf of Mexico) is a tropical estuary of primary concern for its biodiversity, its habitats, and its resource supply, which have been severely impacted by human activities. Fish communities were sampled in four zones of the Terminos Lagoon 18 years apart (1980 and 1998). Two functions performed by fish (food acquisition and locomotion) were studied through the measurement of 16 functional traits. Functional diversity of fish communities was quantified using three independent components: richness, evenness, and divergence. Additionally, we measured the degree of functional specialization in fish communities. We used a null model to compare the functional and the taxonomic structure of fish communities between 1980 and 1998. Among the four largest zones studied, three did not show strong functional changes. In the northern part of the lagoon, we found an increase in fish richness but a significant decrease of functional divergence and functional specialization. We explain this result by a decline of specialized species (i.e., those with particular combinations of traits), while newly occurring species are

  19. Phylogenetic perspectives on the evolution of functional hermaphroditism in teleost fishes.

    Science.gov (United States)

    Erisman, Brad E; Petersen, Christopher W; Hastings, Philip A; Warner, Robert R

    2013-10-01

    Hermaphroditism is taxonomically widespread among teleost fishes and takes on many forms including simultaneous, protogynous, and protandrous hermaphroditism, bidirectional sex change, and androdioecy. The proximate mechanisms that influence the timing, incidence, and forms of hermaphroditism in fishes are supported by numerous theoretical and empirical studies on their mating systems and sexual patterns, but few have examined aspects of sex-allocation theory or the evolution of hermaphroditism for this group within a strict phylogenetic context. Fortunately, species-level phylogenetic reconstructions of the evolutionary history of many lineages of fishes have emerged, providing opportunities for understanding fine-scale evolutionary pathways and transformations of sex allocation. Examinations of several families of fishes with adequate data on phylogeny, patterns of sex allocation, mating systems, and with some form of hermaphroditism reveal that the evolution and expression of protogyny and other forms of sex allocation show little evidence of phylogenetic inertia within specific lineages but rather are associated with particular mating systems in accordance with prevalent theories about sex allocation. Transformations from protogyny to gonochorism in groupers (Epinephelidae), seabasses (Serranidae), and wrasses and parrotfishes (Labridae) are associated with equivalent transformations in the structure of mating groups from spawning of pairs to group spawning and related increases in sperm competition. Similarly, patterns of protandry, androdioecy, simultaneous hermaphroditism, and bidirectional sex change in other lineages (Aulopiformes, Gobiidae, and Pomacentridae) match well with particular mating systems in accordance with sex-allocation theory. Unlike other animals and plants, we did not find evidence that transitions between hermaphroditism and gonochorism required functional intermediates. Two instances in which our general conclusions might not hold

  20. Evolution of mouthbrooding and life-history correlates in the fighting fish genus Betta.

    Science.gov (United States)

    Rüber, Lukas; Britz, Ralf; Tan, Heok Hui; Ng, Peter K L; Zardoya, Rafael

    2004-04-01

    The origin of and evolutionary transitions among the extraordinary diverse forms of parental care in teleost fish remain largely unknown. The "safe harbor" hypothesis predicts that the evolution from a "guarding" to a "brooding" form of care in teleost fish is associated with shifts in reproductive and life-history features such as reduced fecundity, and increased egg volume with higher parental investment. Robust phylogenetic hypotheses may help to identify evolutionary changes in key traits associated with differences in the form of parental care. Here, we used reconstruction of ancestral character states to study the evolution of the two forms of parental care, bubble nesting and mouthbrooding in the fighting fish genus Betta. We also applied a comparative analysis using the phylogenetic generalized least-squares method to test the "safe harbor" hypothesis by evaluating differences between the two forms of parental care in standard length, life-history traits, and three habitat variables. Evolutionary hypotheses were derived from the first molecular phylogeny (nuclear and mitochondrial DNA sequence data; 4448 bp) of this speciose group. Ancestral character state reconstructions of the evolution of the form of parental care in the genus Betta, using the methods of unweighted parsimony and maximum likelihood, are uncertain and further indicate a high rate of evolutionary transitions. Applying different weights for the suspected directionality of changes, based on the consistent phenotypic and behavioral differences found between bubble nesters and mouthbrooders, recurrent origin of mouthbrooding in the genus Betta is favored using parsimony. Our comparative analyses further demonstrate that bubble nesters and mouthbrooders do not have a consistent set of life-history correlates. The form of parental care in Betta is correlated only with offspring size, with mouthbrooders having significantly bigger offspring than bubble nesters, but is not correlated with egg

  1. Tropical fish community does not recover 45 years after predator introduction.

    Science.gov (United States)

    Sharpe, D M T; De León, L F; González, R; Torchin, M E

    2017-02-01

    Predation is considered to be an important factor structuring natural communities. However, it is often difficult to determine how it may influence long-term, broad-scale, diversity patterns, particularly in diverse tropical systems. Biological introductions can provide powerful insight to test the sustained consequences of predation in natural communities, if pre-introduction data are available. Half a century ago, Zaret and Paine demonstrated strong and immediate community-level effects following the introduction of a novel apex predator (peacock bass, Cichla monoculus) into Lake Gatun, Panama. To test for long-term changes associated with this predator introduction, we followed up on their classic study by replicating historical sampling methods and examining changes in the littoral fish community at two sites in Lake Gatun 45 years post-introduction. To broaden our inference, we complemented this temporal comparison with a spatial analysis, wherein we compared the fish communities from two lakes with and one lake without peacock bass. Comparisons with historical data revealed that the peacock bass remains the most abundant predator in Lake Gatun. Furthermore, the collapse of the littoral prey community observed immediately following the invasion has been sustained over the past 45 years. The mean abundance of native littoral fish is now 96% lower than it was prior to the introduction. Diversity (rarefied species richness) declined by 64% post-introduction, and some native species appear to have been locally extirpated. We observed a similar pattern across invaded and uninvaded lakes: the mean abundance of native fishes was 5-40 times lower in lakes with (Gatun, Alajuela) relative to the lake without peacock bass (Bayano). In particular, small-bodied native fishes (Characidae, Peociliidae), which are common prey of the peacock bass, were more than two orders of magnitude (307 times) less abundant in Gatun and one order of magnitude (28 times) less abundant in

  2. Oily Fish Intake and Cognitive Performance in Community-Dwelling Older Adults: The Atahualpa Project.

    Science.gov (United States)

    Del Brutto, Oscar H; Mera, Robertino M; Gillman, Jennifer; Zambrano, Mauricio; Ha, Jung-eun

    2016-02-01

    Due to their high content of omega-3 polyunsaturated fatty acids, oily fish consumption is likely associated with a better cognitive performance. However, information on this association is controversial, with some studies showing a positive effect while others showing no association. We aimed to assess the effects of oily fish consumption on cognitive performance in a population of frequent fish consumers living in rural coastal Ecuador. Atahualpa residents aged ≥60 years were identified during a door-to-door survey and evaluated by the use of the Montreal Cognitive Assessment (MoCA). Oily fish servings per week were calculated in all participants. We estimated whether fish intake correlated with MoCA scores in generalized multivariate linear models adjusted for demographics, cardiovascular risk factors, edentulism and symptoms of depression. Out of 330 eligible persons, 307 (93%) were enrolled. Mean MoCA scores were 19 ± 4.8 points, and mean oily fish consumption was 8.6 ± 5.3 servings per week. In multivariate analyses, MoCA scores were related to fish servings (β 0.097, 95% CI 0.005-0.188, p = 0.038). Locally weighted scatterplot smoothing showed an inflection point in the total MoCA score curve at four fish servings per week. However, predictive margins of the MoCA score were similar across groups below and above this point, suggesting a direct linear relationship between oily fish intake and cognitive performance. Simple preventive measures, such as modifying dietary habits might be of value to reduce the rate of cognitive decline in community-dwelling older adults living in underserved populations.

  3. Dynamical evolution of the community structure of complex earthquake network

    CERN Document Server

    Abe, Sumiyoshi

    2012-01-01

    Earthquake network is known to be complex in the sense that it is scale-free, small-world, hierarchically organized and assortatively mixed. Here, the time evolution of earthquake networks is analyzed around main shocks in the context of the community structure. It is found that the maximum of the modularity measure quantifying existence of communities exhibits a peculiar behavior: its maximum value stays at a large value before a main shock, suddenly drops to a small values at the main shock, and then increases to relax to a large value again relatively slowly. In this way, a main shock is characterized in the language of theory of complex networks. The result is also interpreted in terms of the clustering structure of the earthquake network.

  4. Environmental Control on Fish and Macrocrustacean Spring Community-Structure, on an Intertidal Sandy Beach

    Science.gov (United States)

    Benazza, Achwak; Selleslagh, Jonathan; Breton, Elsa; Rabhi, Khalef; Cornille, Vincent; Bacha, Mahmoud; Lecuyer, Eric; Amara, Rachid

    2015-01-01

    The inter-annual variability of the fish and macrocrustacean spring community on an intertidal sandy beach near the Canche estuary (North of France) was studied from 2000 to 2013 based on weekly spring sampling over an 11-year period. Twenty-eight species representing 21 families were collected during the course of the study. The community was dominated by a few abundant species accounting for > 99% of the total species densities. Most individuals caught were young-of-the-year indicating the importance of this ecosystem for juvenile fishes and macrocrustaceans. Although standard qualitative community ecology metrics (species composition, richness, diversity, evenness and similarity) indicated notable stability over the study period, community structure showed a clear change since 2009. Densities of P. platessa, P. microps and A. tobianus decreased significantly since 2009, whereas over the period 2010-2013, the contribution of S. sprattus to total species density increased 4-fold. Co-inertia and generalised linear model analyses identified winter NAO index, water temperature, salinity and suspended particular matter as the major environmental factors explaining these changes. Although the recurrent and dense spring blooms of the Prymnesiophyte Phaeocystis globosa is one of the main potential threats in shallow waters of the eastern English Channel, no negative impact of its temporal change was detected on the fish and macrocrustacean spring community structure. PMID:25617852

  5. Environmental control on fish and macrocrustacean spring community-structure, on an intertidal sandy beach.

    Directory of Open Access Journals (Sweden)

    Achwak Benazza

    Full Text Available The inter-annual variability of the fish and macrocrustacean spring community on an intertidal sandy beach near the Canche estuary (North of France was studied from 2000 to 2013 based on weekly spring sampling over an 11-year period. Twenty-eight species representing 21 families were collected during the course of the study. The community was dominated by a few abundant species accounting for > 99% of the total species densities. Most individuals caught were young-of-the-year indicating the importance of this ecosystem for juvenile fishes and macrocrustaceans. Although standard qualitative community ecology metrics (species composition, richness, diversity, evenness and similarity indicated notable stability over the study period, community structure showed a clear change since 2009. Densities of P. platessa, P. microps and A. tobianus decreased significantly since 2009, whereas over the period 2010-2013, the contribution of S. sprattus to total species density increased 4-fold. Co-inertia and generalised linear model analyses identified winter NAO index, water temperature, salinity and suspended particular matter as the major environmental factors explaining these changes. Although the recurrent and dense spring blooms of the Prymnesiophyte Phaeocystis globosa is one of the main potential threats in shallow waters of the eastern English Channel, no negative impact of its temporal change was detected on the fish and macrocrustacean spring community structure.

  6. Diet compositions and trophic guild structure of the eastern Chukchi Sea demersal fish community

    Science.gov (United States)

    Whitehouse, George A.; Buckley, Troy W.; Danielson, Seth L.

    2017-01-01

    Fishes are an important link in Arctic marine food webs, connecting production of lower trophic levels to apex predators. We analyzed 1773 stomach samples from 39 fish species collected during a bottom trawl survey of the eastern Chukchi Sea in the summer of 2012. We used hierarchical cluster analysis of diet dissimilarities on 21 of the most well sampled species to identify four distinct trophic guilds: gammarid amphipod consumers, benthic invertebrate generalists, fish and shrimp consumers, and zooplankton consumers. The trophic guilds reflect dominant prey types in predator diets. We used constrained analysis of principal coordinates (CAP) to determine if variation within the composite guild diets could be explained by a suite of non-diet variables. All CAP models explained a significant proportion of the variance in the diet matrices, ranging from 7% to 25% of the total variation. Explanatory variables tested included latitude, longitude, predator length, depth, and water mass. These results indicate a trophic guild structure is present amongst the demersal fish community during summer in the eastern Chukchi Sea. Regular monitoring of the food habits of the demersal fish community will be required to improve our understanding of the spatial, temporal, and interannual variation in diet composition, and to improve our ability to identify and predict the impacts of climate change and commercial development on the structure and functioning of the Chukchi Sea ecosystem.

  7. Statistical power to detect change in a mangrove shoreline fish community adjacent to a nuclear power plant.

    Science.gov (United States)

    Dolan, T E; Lynch, P D; Karazsia, J L; Serafy, J E

    2016-03-01

    An expansion is underway of a nuclear power plant on the shoreline of Biscayne Bay, Florida, USA. While the precise effects of its construction and operation are unknown, impacts on surrounding marine habitats and biota are considered by experts to be likely. The objective of the present study was to determine the adequacy of an ongoing monitoring survey of fish communities associated with mangrove habitats directly adjacent to the power plant to detect fish community changes, should they occur, at three spatial scales. Using seasonally resolved data recorded during 532 fish surveys over an 8-year period, power analyses were performed for four mangrove fish metrics (fish diversity, fish density, and the occurrence of two ecologically important fish species: gray snapper (Lutjanus griseus) and goldspotted killifish (Floridichthys carpio). Results indicated that the monitoring program at current sampling intensity allows for detection of monitoring programs for improved, focused change detection deserves consideration from both ecological and cost-benefit perspectives.

  8. Reef fish community in presence of the lionfish (Pterois volitans in Santa Marta, Colombian Caribbean

    Directory of Open Access Journals (Sweden)

    Rocío García-Urueña

    2015-11-01

    Full Text Available Objective. Fish species community structure and benthic organisms coverage were studied in five localities in Santa Marta where the lionfish is present. Materials and methods. Abundance of fish species, including lion fish, was established using 30 m random visual censuses and video transects; trophic guilds were established according to available references. On the other hand benthic coverage was evaluated using the software Coral Point Count (CPCe 4.0. Results. Families with higher species numbers were Serranidae, Labridae, and Pomacentridae. Lionfish abundances were low (2.6±2.1 ind/120 m2, but in any case Pterois volitans was observed as the eleventh more abundant species, surpassing species of commercial value such as Cephalopholis cruentata. Species that were found in larger numbers (>100, Thalassoma bifasciatum, Haemulon aurolineatum, Canthigaster rostrata, Abudefduf saxatilis, Chromis cyanea, and Stegastes partitus were mainly invertebrate eaters, planctivores, and territorial herbivores. Coral coverage showed higher coral percentages in Chengue (69.9% and Cinto (27.4%, larger sponge percentages in Morro (32.7%; Isla Aguja and Remanso showed the larger figures for abiotic substrate (41.6 and 37%, respectively; corals, sponges, and gorgonians were the components best explaining fish community, but not for the lion fish, which inhabit all studied reef formations. Conclusions. Lion fish is ranked between the 20 more abundant species, with none commercially important species larger, hence no species may qualify as a natural control. Lion fish has as well become a relatively abundant species in Santa Marta reefs, independent of benthic coverage.

  9. Methylmercury exposure in a subsistence fishing community in Lake Chapala, Mexico: an ecological approach

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    Abercrombie Mary I

    2010-01-01

    Full Text Available Abstract Background Elevated concentrations of mercury have been documented in fish in Lake Chapala in central Mexico, an area that is home to a large subsistence fishing community. However, neither the extent of human mercury exposure nor its sources and routes have been elucidated. Methods Total mercury concentrations were measured in samples of fish from Lake Chapala; in sections of sediment cores from the delta of Rio Lerma, the major tributary to the lake; and in a series of suspended-particle samples collected at sites from the mouth of the Lerma to mid-Lake. A cross-sectional survey of 92 women ranging in age from 18-45 years was conducted in three communities along the Lake to investigate the relationship between fish consumption and hair mercury concentrations among women of child-bearing age. Results Highest concentrations of mercury in fish samples were found in carp (mean 0.87 ppm. Sediment data suggest a pattern of moderate ongoing contamination. Analyses of particles filtered from the water column showed highest concentrations of mercury near the mouth of the Lerma. In the human study, 27.2% of women had >1 ppm hair mercury. On multivariable analysis, carp consumption and consumption of fish purchased or captured from Lake Chapala were both associated with significantly higher mean hair mercury concentrations. Conclusions Our preliminary data indicate that, despite a moderate level of contamination in recent sediments and suspended particulate matter, carp in Lake Chapala contain mercury concentrations of concern for local fish consumers. Consumption of carp appears to contribute significantly to body burden in this population. Further studies of the consequences of prenatal exposure for child neurodevelopment are being initiated.

  10. Aquatic insects as the main food resource of fish the community in a Neotropical reservoir

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    Ana Paula Vidotto-Magnoni

    Full Text Available We evaluated the feeding of fish species of the Nova Avanhandava Reservoir, low Tietê River, São Paulo State, Brazil. Fishes were collected in two stretches of the reservoir: Santa Bárbara (14 samples and Bonito (two samples between September 2002 and March 2004, using gill and seining nets. The results of stomach contents analysis were expressed with the frequency of occurrence and gravimetric method, combined in the Alimentary Index (AI. The 20 species studied consumed 52 food items, grouped in 10 food categories: aquatic insects, terrestrial insects, crustaceans, fish, macroinvertebrates, microcrustaceans, algae, vegetal matter, detritus/sediment and scales. The aquatic insects (mainly Chironomidae, Odonata and Ephemeroptera were the most common food resources, consumed by 18 species. The diet composition of the community (species grouped indicated that the dominant food category in the diet of fishes was aquatic insects (AI = 77.6%, followed by crustaceans (AI = 7.1%. Four trophic guilds were identified according a cluster analysis (Pearson distance: insectivorous (10 species, omnivorous (4 species, detritivorous (3 species and piscivorous/carcinophagous (3 species. Despite the highest number of species, the insectivorous guild was responsible for more than 80% in captures in number and biomass (CPUEn and CPUEb. The low values of niche breadth presented by all species, along with the low values of diet overlap between species pairs indicate a high degree of food resources partitioning among species. The aquatic insects, despite being the main food resource of insectivorous fishes, also complemented the diet of other species, which demonstrate the importance of this food resource for the fish community, sustaining a high diversity, abundance and biomass of fishes.

  11. Low functional β-diversity despite high taxonomic β-diversity among tropical estuarine fish communities.

    Science.gov (United States)

    Villéger, Sébastien; Ramos Miranda, Julia; Flores Hernandez, Domingo; Mouillot, David

    2012-01-01

    The concept of β-diversity, defined as dissimilarity among communities, has been widely used to investigate biodiversity patterns and community assembly rules. However, in ecosystems with high taxonomic β-diversity, due to marked environmental gradients, the level of functional β-diversity among communities is largely overlooked while it may reveal processes shaping community structure. Here, decomposing biodiversity indices into α (local) and γ (regional) components, we estimated taxonomic and functional β-diversity among tropical estuarine fish communities, through space and time. We found extremely low functional β-diversity values among fish communities (<1.5%) despite high dissimilarity in species composition and species dominance. Additionally, in contrast to the high α and γ taxonomic diversities, α and γ functional diversities were very close to the minimal value. These patterns were caused by two dominant functional groups which maintained a similar functional structure over space and time, despite the strong dissimilarity in taxonomic structure along environmental gradients. Our findings suggest that taxonomic and functional β-diversity deserve to be quantified simultaneously since these two facets can show contrasting patterns and the differences can in turn shed light on community assembly rules.

  12. Fish communities of a disturbed mangrove wetland and an adjacent tidal river in Palmar, Ecuador

    Science.gov (United States)

    Shervette, V. R.; Aguirre, W. E.; Blacio, E.; Cevallos, Rodrigo; Gonzalez, Marcelo; Pozo, Francisco; Gelwick, F.

    2007-03-01

    Coastal Ecuador has lost 20-30% of mangrove wetlands over the past 30 years. Such habitat loss can impair the ecological functions of wetlands. A paucity of information exists concerning mangrove fish communities of Ecuador. In this study we identify the fish community of the remaining mangrove wetland in Palmar, Ecuador. Fish were sampled in the dry season of 2003 and the wet season of 2004 by seining in mangrove creeks and Main channel of Rio Palmar. For comparison, an adjacent tidal river without mangroves, Rio Javita, was also sampled. We collected a total of 12,231 individuals comprising 36 species in 16 families from Rios Palmar and Javita. Gobiidae (7 species) was the most diverse family for mangrove sites followed by Gerreidae (5 species) and Engraulidae (4 species). A total of 34 species were collected in the mangrove wetland, 21 of which were exclusive to the mangroves including three species of juvenile snook (Centropomidae), indicating that the mangrove habitat of Palmar may provide nursery habitat for these economically valued species. In Rio Javita, Carangidae (3 species) was the most diverse family followed by Engraulidae and Gerreidae (2 species each). A total of 14 species were collected in the tidal river, only two of which were exclusive to the river. Multivariate analyses of fish community data indicated significant differences in community composition between the mangrove creeks and the tidal river and between seasons in both. Juvenile white mullet, Mugil curema, were collected in high relative abundance in both Rios Palmar and Javita, as was the tropical silverside Atherinella serrivomer an ecologically important species. Although Rios Palmar and Javita are characterized by relatively low fish species richness compared to other tropical estuarine systems, they appear to provide an important habitat for several economically and ecologically valued species.

  13. Transactional sex and HIV: understanding the gendered structural drivers of HIV in fishing communities in Southern Malawi

    Directory of Open Access Journals (Sweden)

    Janet Seeley

    2012-06-01

    Full Text Available Background: In Southern Malawi, the fishing industry is highly gendered, with men carrying out the fishing and women processing, drying and selling the fish. Research has shown that individuals living in fishing communities in low-income countries are particularly vulnerable to HIV infection. One of the key drivers of HIV in fishing communities is transactional sex. In the fishing industry this takes the form of “fish-for-sex” networks where female fish traders exchange sex with fishermen for access to or more favourable prices of fish. By controlling the means of production, the power dynamics in these exchanges favour men and can make it more difficult for women to negotiate safe sex. Methods: Qualitative methods were used to collect data on gendered drivers of transactional sex in the fishing community and how different groups perceive HIV risk in these transactions. Observation, focus group discussions and semi-structured interviews were undertaken with members of the fishing communities, including men and women directly and indirectly involved in fishing. Results: In fishing communities transactional sex was prevalent across a spectrum ranging from gift giving within relationships, to sex for fish exchanges, to sex worker encounters. Power differences between couples in transactional sexual encounters shape individual's abilities to negotiate condom use (with women being at a particularly disadvantaged negotiating position. The context and motivations for transactional sex varied and was mediated by economic need and social position both of men and women. Female fish traders new to the industry and boat crew members who travelled for work and experienced difficult living conditions often engaged in transactional sex. Conclusions: Transactional sex is common in Malawian fishing communities, with women particularly vulnerable in negotiations because of existing gendered power structures. Although knowledge and understanding of the HIV

  14. Characterization of water quality and biological communities, Fish Creek, Teton County, Wyoming, 2007-2011

    Science.gov (United States)

    Eddy-Miller, Cheryl A.; Peterson, David A.; Wheeler, Jerrod D.; Edmiston, C. Scott; Taylor, Michelle L.; Leemon, Daniel J.

    2013-01-01

    Fish Creek, an approximately 25-kilometer-long tributary to Snake River, is located in Teton County in western Wyoming near the town of Wilson. Fish Creek is an important water body because it is used for irrigation, fishing, and recreation and adds scenic value to the Jackson Hole properties it runs through. Public concern about nuisance growths of aquatic plants in Fish Creek has been increasing since the early 2000s. To address these concerns, the U.S. Geological Survey conducted a study in cooperation with the Teton Conservation District to characterize the hydrology, water quality, and biologic communities of Fish Creek during 2007–11. The hydrology of Fish Creek is strongly affected by groundwater contributions from the area known as the Snake River west bank, which lies east of Fish Creek and west of Snake River. Because of this continuous groundwater discharge to the creek, land-use activities in the west bank area can affect the groundwater quality. Evaluation of nitrate isotopes and dissolved-nitrate concentrations in groundwater during the study indicated that nitrate was entering Fish Creek from groundwater, and that the source of nitrate was commonly a septic/sewage effluent or manure source, or multiple sources, potentially including artificial nitrogen fertilizers, natural soil organic matter, and mixtures of sources. Concentrations of dissolved nitrate and orthophosphate, which are key nutrients for growth of aquatic plants, generally were low in Fish Creek and occasionally were less than reporting levels (not detected). One potential reason for the low nutrient concentrations is that nutrients were being consumed by aquatic plant life that increases during the summer growing season, as a result of the seasonal increase in temperature and larger number of daylight hours. Several aspects of Fish Creek’s hydrology contribute to higher productivity and biovolume of aquatic plants in Fish Creek than typically observed in streams of its size in

  15. Resilience of coral-associated bacterial communities exposed to fish farm effluent.

    Science.gov (United States)

    Garren, Melissa; Raymundo, Laurie; Guest, James; Harvell, C Drew; Azam, Farooq

    2009-10-06

    The coral holobiont includes the coral animal, algal symbionts, and associated microbial community. These microbes help maintain the holobiont homeostasis; thus, sustaining robust mutualistic microbial communities is a fundamental part of long-term coral reef survival. Coastal pollution is one major threat to reefs, and intensive fish farming is a rapidly growing source of this pollution. We investigated the susceptibility and resilience of the bacterial communities associated with a common reef-building coral, Porites cylindrica, to coastal pollution by performing a clonally replicated transplantation experiment in Bolinao, Philippines adjacent to intensive fish farming. Ten fragments from each of four colonies (total of 40 fragments) were followed for 22 days across five sites: a well-flushed reference site (the original fragment source); two sites with low exposure to milkfish (Chanos chanos) aquaculture effluent; and two sites with high exposure. Elevated levels of dissolved organic carbon (DOC), chlorophyll a, total heterotrophic and autotrophic bacteria abundance, virus like particle (VLP) abundances, and culturable Vibrio abundance characterized the high effluent sites. Based on 16S rRNA clone libraries and denaturing gradient gel electrophoresis (DGGE) analysis, we observed rapid, dramatic changes in the coral-associated bacterial communities within five days of high effluent exposure. The community composition on fragments at these high effluent sites shifted towards known human and coral pathogens (i.e. Arcobacter, Fusobacterium, and Desulfovibrio) without the host corals showing signs of disease. The communities shifted back towards their original composition by day 22 without reduction in effluent levels. This study reveals fish farms as a likely source of pathogens with the potential to proliferate on corals and an unexpected short-term resilience of coral-associated bacterial communities to eutrophication pressure. These data highlight a need for

  16. Resilience of coral-associated bacterial communities exposed to fish farm effluent.

    Directory of Open Access Journals (Sweden)

    Melissa Garren

    Full Text Available The coral holobiont includes the coral animal, algal symbionts, and associated microbial community. These microbes help maintain the holobiont homeostasis; thus, sustaining robust mutualistic microbial communities is a fundamental part of long-term coral reef survival. Coastal pollution is one major threat to reefs, and intensive fish farming is a rapidly growing source of this pollution.We investigated the susceptibility and resilience of the bacterial communities associated with a common reef-building coral, Porites cylindrica, to coastal pollution by performing a clonally replicated transplantation experiment in Bolinao, Philippines adjacent to intensive fish farming. Ten fragments from each of four colonies (total of 40 fragments were followed for 22 days across five sites: a well-flushed reference site (the original fragment source; two sites with low exposure to milkfish (Chanos chanos aquaculture effluent; and two sites with high exposure. Elevated levels of dissolved organic carbon (DOC, chlorophyll a, total heterotrophic and autotrophic bacteria abundance, virus like particle (VLP abundances, and culturable Vibrio abundance characterized the high effluent sites. Based on 16S rRNA clone libraries and denaturing gradient gel electrophoresis (DGGE analysis, we observed rapid, dramatic changes in the coral-associated bacterial communities within five days of high effluent exposure. The community composition on fragments at these high effluent sites shifted towards known human and coral pathogens (i.e. Arcobacter, Fusobacterium, and Desulfovibrio without the host corals showing signs of disease. The communities shifted back towards their original composition by day 22 without reduction in effluent levels.This study reveals fish farms as a likely source of pathogens with the potential to proliferate on corals and an unexpected short-term resilience of coral-associated bacterial communities to eutrophication pressure. These data highlight a

  17. An approach of community evolution based on gravitational relationship refactoring in dynamic networks

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Guisheng; Chi, Kuo, E-mail: chik89769@hrbeu.edu.cn; Dong, Yuxin; Dong, Hongbin

    2017-04-25

    In this paper, an approach of community evolution based on gravitational relationship refactoring between the nodes in a dynamic network is proposed, and it can be used to simulate the process of community evolution. A static community detection algorithm and a dynamic community evolution algorithm are included in the approach. At first, communities are initialized by constructing the core nodes chains, the nodes can be iteratively searched and divided into corresponding communities via the static community detection algorithm. For a dynamic network, an evolutionary process is divided into three phases, and behaviors of community evolution can be judged according to the changing situation of the core nodes chain in each community. Experiments show that the proposed approach can achieve accuracy and availability in the synthetic and real world networks. - Highlights: • The proposed approach considers both the static community detection and dynamic community evolution. • The approach of community evolution can identify the whole 6 common evolution events. • The proposed approach can judge the evolutionary events according to the variations of the core nodes chains.

  18. Proposed Methods and Endpoints for Defining and Assessing Adverse Environmental Impact (AEI on Fish Communities/Populations in Tennessee River Reservoirs

    Directory of Open Access Journals (Sweden)

    Gary D. Hickman

    2002-01-01

    Full Text Available Two multimetric indices have been developed to help address fish community (reservoir fish assemblage index [RFAI] and individual population quality (sport fishing index [SFI] in Tennessee River reservoirs. The RFAI, with characteristics similar to the index of biotic integrity (IBI used in stream fish community determinations, was developed to monitor the existing condition of resident fish communities[1,2,3]. The index, which incorporates standardized electrofishing of littoral areas and experimental gill netting for limnetic bottom-dwelling species, has been used to determine residential fish community response to various anthropogenic impacts in southeastern reservoirs.

  19. Composition and temporal patterns of larval fish communities in Chesapeake and Delaware Bays

    Directory of Open Access Journals (Sweden)

    Filipe Ribeiro

    2015-11-01

    Full Text Available Comparing larval fish assemblages in different estuaries provides insights about the coastal distribution of larval populations, larval transport, and adult spawning locations (Ribeiro et al. 2015. We simultaneously compared the larval fish assemblages entering two Middle Atlantic Bight (MAB estuaries (Delaware Bay and Chesapeake Bay, USA through weekly sampling from 2007 to 2009. In total, 43 taxa (32 families and 36 taxa (24 families were collected in Delaware and Chesapeake Bays, respectively. Mean taxonomic diversity, mean richness, and evenness were generally lower in Delaware Bay. Communities of both bays were dominated by Anchoa spp., Gobiosoma spp., Micropogonias undulatus, and Brevoortia tyrannus; Paralichthys spp. was more abundant in Delaware Bay and Microgobius thalassinus was more abundant in Chesapeake Bay. Inter-annual variation in the larval fish communities was low at both sites, with a relatively consistent composition across years, but strong seasonal (intra-annual variation in species composition occurred in both bays. Two groups were identified in Chesapeake Bay: a ‘winter’ group dominated by shelf-spawned species (e.g. M. undulatus and a ‘summer’ group comprising obligate estuarine species and coastal species (e.g. Gobiosoma spp. and Cynoscion regalis, respectively. In Delaware Bay, 4 groups were identified: a ‘summer’ group of mainly obligate estuarine fishes (e.g. Menidia sp. being replaced by a ‘fall’ group (e.g. Ctenogobius boleosoma and Gobionellus oceanicus; ‘winter’ and ‘spring’ groups were dominated by shelf-spawned (e.g. M. undulatus and Paralichthys spp. and obligate estuarine species (e.g. Leiostomus xanthurus and Pseudopleuronectes americanus, respectively. This study demonstrates that inexpensive and simultaneous sampling in different estuaries provides important insights into the variability in community structure of fish assemblages at large spatial scales.

  20. Relationships between reef fish communities and remotely sensed rugosity measurements in Biscayne National Park, Florida, USA

    Science.gov (United States)

    Kuffner, Ilsa B.; Brock, John C.; Grober-Dunsmore, Rikki; Bonito, Victor E.; Hickey, T. Donald; Wright, C. Wayne

    2007-01-01

    The realization that coral reef ecosystem management must occur across multiple spatial scales and habitat types has led scientists and resource managers to seek variables that are easily measured over large areas and correlate well with reef resources. Here we investigate the utility of new technology in airborne laser surveying (NASA Experimental Advanced Airborne Research Lidar (EAARL)) in assessing topographical complexity (rugosity) to predict reef fish community structure on shallow (n = 10–13 per reef). Rugosity at each station was assessed in situ by divers using the traditional chain-transect method (10-m scale), and remotely using the EAARL submarine topography data at multiple spatial scales (2, 5, and 10 m). The rugosity and biological datasets were analyzed together to elucidate the predictive power of EAARL rugosity in describing the variance in reef fish community variables and to assess the correlation between chain-transect and EAARL rugosity. EAARL rugosity was not well correlated with chain-transect rugosity, or with species richness of fishes (although statistically significant, the amount of variance explained by the model was very low). Variance in reef fish community attributes was better explained in reef-by-reef variability than by physical variables. However, once the reef-by-reef variability was taken into account in a two-way analysis of variance, the importance of rugosity could be seen on individual reefs. Fish species richness and abundance were statistically higher at high rugosity stations compared to medium and low rugosity stations, as predicted by prior ecological research. The EAARL shows promise as an important mapping tool for reef resource managers as they strive to inventory and protect coral reef resources.

  1. Adirondack lakes survey: An interpretive analysis of fish communities and water chemistry, 1984--1987

    Energy Technology Data Exchange (ETDEWEB)

    Baker, J.P. (Baker (Joan P.), Raleigh, NC (USA)); Gherini, S.A.; Munson, R.K. (Tetra Tech, Inc., Pasadena, CA (USA)); Christensen, S.W. (Oak Ridge National Lab., TN (USA)); Driscoll, C.T. (Syracuse Univ., NY (USA)); Gallagher, J. (Adirondack Lakes Survey Corp., Ray Brook, NY (USA)); Newton, R.M. (Smith Coll., Northampton, MA (USA)); Reckhow, K.H. (Duke Univ., Durham, NC (USA)); Schofield, C.L. (Co

    1990-01-01

    The Adirondack Lakes Survey Corporation (ALSC) was formed as a cooperative effort of the New York State Department of Environmental Conservation and the Empire State Electric Energy Research Corporation to better characterize the chemical and biological status of Adirondack lakes. Between 1984 and 1987, the ALSC surveyed 1469 lakes within the Adirondack ecological zone. As a follow-up to the survey, the ALSC sponsored a series of interpretive analyses of the ALSC data base. The primary objectives of these analyses were as follows: Evaluate the influence of mineral acids (from acidic deposition) and nonmineral acids (natural organic acids) on lake pH levels; classify Adirondack lakes according to lake and watershed features expected to influence their responsiveness to changes in acidic deposition; evaluate the sensitivity of Adirondack lakes to changes in environmental conditions, such as changes in mineral acids or dissolved organic carbon concentrations; identify lake characteristics important in explaining the observed present-day status of fish communities in Adirondack lakes, in particular the relative importance of lake acidity; evaluate changes that have occurred over time in Adirondack fish communities and probable causes for these trends by using the available historical data on fish communities in the Adirondacks and the ALSC data base; and determine the degree to which the existing fish resource might be at risk from continued acidic deposition, or might recover if acidity levels were reduced. The basic approach examined relationships observed in the ALSC data base among watershed characteristics, lake chemistry, and fish status. Individual reports are processed separately for the data bases.

  2. Reconstructing riverine mesohabitat unit composition using fish community data and an autecology matrix.

    Science.gov (United States)

    Suen, J P; Su, W C

    2010-09-01

    This research proposes a simplified method for estimating the mesohabitat composition that would favour members of a given set of aquatic species. The simulated composition of four types of mesohabitat units (deep pool, shallow pool, deep riffle and shallow riffle) could guide the design of in-stream structures in creating pool-riffle systems with ecological reference. Fish community data and an autecology matrix are used to support the development of a stream mesohabitat simulation based on regression models for reaches in mid to upper-order streams. The fish community-mesohabitat model results constitute a reference condition that can be used to guide stream restoration and ecological engineering decisions aimed at maintaining the natural ecological integrity and diversity of rivers.

  3. Breaking the Bounds of Rationality: Values, Relationships, and Decision-making in Mexican Fishing Communities

    Directory of Open Access Journals (Sweden)

    Nicole D Peterson

    2014-01-01

    Full Text Available In fishing communities in Baja California Sur, Mexico, fisheries management is heavily influenced by models of individual economic rationality held by biologists and others involved in management, in which fishermen ′choose′ to overfish because they are motivated by selfish individual rationality. Yet there is much that is neglected by these models, including the pressures of economic markets, family and community expectations, and cultural and personal value systems. Actual decisions about fishing and resource management rarely match the expectations of classical or neoliberal economic models of individual behaviour. I argue here that rational choice theory is a historically and culturally constructed discourse that becomes a taken-for-granted lens for viewing behaviour around the world. The effects of this discourse can be seen in the policies that are derived from them, as shown through this case study.

  4. Hair mercury levels in relation to fish consumption in a community of the Moroccan Mediterranean coast.

    Science.gov (United States)

    Elhamri, Hecham; Idrissi, Larbi; Coquery, Marina; Azemard, Sabine; El Abidi, Abdellah; Benlemlih, Mohamed; Saghi, Mohamed; Cubadda, Francesco

    2007-11-01

    Coastal populations with high seafood consumption in the Mediterranean have a significant exposure to dietary methylmercury, and areas where environmental mercury pollution is an issue due to industrial activities are of special concern. The study was undertaken with the aim of assessing methylmercury exposure through fish consumption in a community of north Morocco and characterizing the relevant health risk. Concentrations of total mercury were determined in human hair, a biomarker of methylmercury exposure, and in locally consumed fish by cold vapour atomic absorption spectrophotometry. Based on consumption frequencies reported by the 108 subjects included in the study the weekly intake of methylmercury was estimated and biomarker data were evaluated in relation to the estimated intake and the sociodemographic characteristics of the population. Multiple regression analysis was employed for the interpretation of hair mercury data in relation to fish consumption frequency, gender and the age of individuals. Mercury concentrations in hair ranged from 0.22 to 9.56 microg g(-1) (geometric mean = 1.79 microg g(-1)) and were closely related to fish intake. Fisherman and their families consumed fish three to five times per week and were the most exposed population subgroup. A high proportion of women of child-bearing age (50%) had relatively high levels of mercury in their hair (3.08-7.88 microg g(-1)).

  5. Evolution of egg dummies in Tanganyikan cichlid fishes: the roles of parental care and sexual selection.

    Science.gov (United States)

    Amcoff, M; Gonzalez-Voyer, A; Kolm, N

    2013-11-01

    Sexual selection has been suggested to be an important driver of speciation in cichlid fishes of the Great Lakes of Africa, and the presence of male egg dummies is proposed to have played a key role. Here, we investigate how mouthbrooding and egg dummies have evolved in Tanganyikan cichlids, the lineage which seeded the other African radiations, with a special emphasis on the egg dummies. Using modern phylogenetic comparative analyses and a phylogeny including 86% of the 200 described species, we provide formal evidence demonstrating correlated evolution between mouthbrooding and egg dummies in Tanganyikan cichlids. These results concur with existing evidence, suggesting that egg dummies have evolved through sensory exploitation. We also demonstrate that there is a strong evolutionary correlation between the presence of egg dummies and both pre- and post-copulatory sexual selection. Moreover, egg dummy evolution was contingent on the intensity of pre- and post-copulatory sexual selection in Tanganyikan cichlids. In sum, our results provide evidence supporting the hypothesis of egg dummies evolving through sensory exploitation and highlight the role of sexual selection in favouring the evolution and maintenance of this trait. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  6. Fish communities in coastal freshwater ecosystems: the role of the physical and chemical setting

    OpenAIRE

    Arend Kristin K; Bain Mark B

    2008-01-01

    Abstract Background We explored how embayment watershed inputs, morphometry, and hydrology influence fish community structure among eight embayments located along the southeastern shoreline of Lake Ontario, New York, USA. Embayments differed in surface area and depth, varied in their connections to Lake Ontario and their watersheds, and drained watersheds representing a gradient of agricultural to forested land use. Results We related various physicochemical factors, including total phosphoru...

  7. Opinion evolution and rare events in an open community

    Science.gov (United States)

    Ye, Yusong; Yang, Zhuoqin; Zhang, Zili

    2016-11-01

    There are many multi-stable phenomena in society. To explain these multi-stable phenomena, we have studied opinion evolution in an open community. We focus on probability of transition (or the mean transition time) that the system transfer from one state to another. We suggest a bistable model to provide an interpretation of these phenomena. The quasi-potential method that we used is the most important method to calculate the transition time and it can be used to determine the whole probability density. We study the condition of bistability and then discuss rare events in a multi-stable system. In our model, we find that two parameters, ;temperature; and ;persuading intensity,; influence the behavior of the system; a suitable ;persuading intensity; and low ;temperature; make the system more stable. This means that the transition rarely happens. The asymmetric phenomenon caused by ;public-opinion; is also discussed.

  8. Impact of mass coral bleaching on reef fish community and fishermen catches at Sabang, Aceh Province, Indonesia

    OpenAIRE

    Edi Rudi; Taufiq Iskandar; Nur Fadli; Hidayati Hidayati

    2012-01-01

    Mass coral bleaching was observed at Sabang, Aceh in early 2010, and approximately 60% ofhard coral in waters surrounding Sabang died post-event. Coral mortality was expected to affect thecomposition of reef fish due to decrease its function such as providing a shelter, feeding and spawninggrounds for fish and other marine organisms. The objectives of this research were to evaluate the impactof coral bleaching on coral reef fish community and to compare the composition of fishermen catchesbef...

  9. Impact of mass coral bleaching on reef fish community and fishermen catches at Sabang, Aceh Province, Indonesia

    OpenAIRE

    Edi Rudi; Taufiq Iskandar; Nur Fadli; Hidayati Hidayati

    2012-01-01

    Mass coral bleaching was observed at Sabang, Aceh in early 2010, and approximately 60% ofhard coral in waters surrounding Sabang died post-event. Coral mortality was expected to affect thecomposition of reef fish due to decrease its function such as providing a shelter, feeding and spawninggrounds for fish and other marine organisms. The objectives of this research were to evaluate the impactof coral bleaching on coral reef fish community and to compare the composition of fishermen catchesbef...

  10. Spatial variation in coral reef fish and benthic communities in the central Saudi Arabian Red Sea

    KAUST Repository

    Khalil, Maha T.

    2017-06-06

    Local-scale ecological information is critical as a sound basis for spatial management and conservation and as support for ongoing research in relatively unstudied areas. We conducted visual surveys of fish and benthic communities on nine reefs (3–24 km from shore) in the Thuwal area of the central Saudi Arabian Red Sea. Fish biomass increased with increasing distance from shore, but was generally low compared to reefs experiencing minimal human influence around the world. All reefs had a herbivore-dominated trophic structure and few top predators, such as sharks, jacks, or large groupers. Coral cover was considerably lower on inshore reefs, likely due to a 2010 bleaching event. Community analyses showed inshore reefs to be characterized by turf algae, slower-growing corals, lower herbivore diversity, and highly abundant turf-farming damselfishes. Offshore reefs had more planktivorous fishes, a more diverse herbivore assemblage, and faster-growing corals. All reefs appear to be impacted by overfishing, and inshore reefs seem more vulnerable to thermal bleaching. The study provides a description of the spatial variation in biomass and community structure in the central Saudi Arabian Red Sea and provides a basis for spatial prioritization and subsequent marine protected area design in Thuwal.

  11. Spatial variation in coral reef fish and benthic communities in the central Saudi Arabian Red Sea

    Directory of Open Access Journals (Sweden)

    Maha T. Khalil

    2017-06-01

    Full Text Available Local-scale ecological information is critical as a sound basis for spatial management and conservation and as support for ongoing research in relatively unstudied areas. We conducted visual surveys of fish and benthic communities on nine reefs (3–24 km from shore in the Thuwal area of the central Saudi Arabian Red Sea. Fish biomass increased with increasing distance from shore, but was generally low compared to reefs experiencing minimal human influence around the world. All reefs had a herbivore-dominated trophic structure and few top predators, such as sharks, jacks, or large groupers. Coral cover was considerably lower on inshore reefs, likely due to a 2010 bleaching event. Community analyses showed inshore reefs to be characterized by turf algae, slower-growing corals, lower herbivore diversity, and highly abundant turf-farming damselfishes. Offshore reefs had more planktivorous fishes, a more diverse herbivore assemblage, and faster-growing corals. All reefs appear to be impacted by overfishing, and inshore reefs seem more vulnerable to thermal bleaching. The study provides a description of the spatial variation in biomass and community structure in the central Saudi Arabian Red Sea and provides a basis for spatial prioritization and subsequent marine protected area design in Thuwal.

  12. Anthropic effects on the fish community of Ribeirão Claro, Rio Claro, SP, Brazil

    Directory of Open Access Journals (Sweden)

    FC. Ferreira

    Full Text Available The effect of anthropic alterations such as drain discharge on a fish community was studied in the Ribeirão Claro River, municipality of Rio Claro, State of São Paulo, southeastern Brazil. Samples were made monthly in three different points along the river (headwaters, mid course, and confluence between December, 2003 and March, 2004, which is the reproductive period for the majority of the species. The fish community of the Ribeirão Claro River showed a fair composition and diversity, with species rarely observed in studies made in the region, such as Paravandellia oxyfera and Callichthys callichthys. Indices of diversity and equitability showed different results when weight or the number of individuals were considered. Moreover, these indices did not reveal the typical increase in diversity from the headwaters toward the confluence, nor the loss of richness in the part altered by drain discharge. An interpretation should be made with caution, taking into account the diverse factors included in the computation. Similar to the diversity indices, the Morisita-Horn similarity index did not reveal a great difference in the fish community of the confluence of the river, mainly in relation to its mid course. The decline of species richness and trophic composition alteration in the disturbed part is clear, which shows a great dominance of piscivorous species.

  13. Geological differentiation explains diversity and composition of fish communities in upland streams in the southern Amazon of Colombia

    NARCIS (Netherlands)

    Arbeláez, F.; Duivenvoorden, J.F.; Maldonado-Ocampo, J.A.

    2008-01-01

    Fish biomass, species richness and composition were compared between upland streams draining two contrasting geological units (Pebas and Tsa) in Colombian Amazonia. Because Pebas sediments reportedly show higher levels of base concentrations than Tsa sediments, we expected that the fish communities

  14. Assessing the state of pelagic fish communities within an ecosystem approach and the European Marine Strategy Framework Directive

    NARCIS (Netherlands)

    Shephard, S.; Rindorf, A.; Dickey-Collas, M.; Hintzen, N.T.; Farnsworth, K.; Reid, D.G.

    2014-01-01

    Pelagic fish are key elements in marine foodwebs and thus comprise an important part of overall ecosystem health. We develop a suite of ecological indicators that track pelagic fish community state and evaluate state of specific objectives against Good Environmental Status (GES) criteria. Indicator

  15. The composition of fish communities of nine Ethiopian lakes along a north-south gradient: threats and possible solutions

    NARCIS (Netherlands)

    Vijverberg, J.; Dejen, E.; Getahun, A.; Nagelkerke, L.A.J.

    2012-01-01

    Fish populations of nine Ethiopian freshwater lakes were quantitatively sampled with a standardized protocol, using multi-mesh gill nets. In total, 27 species were identified, but only 14 species were common. Based on the common species, the fish communities showed large differences in their species

  16. The composition of fish communities of nine Ethiopian lakes along a north-south gradient: threats and possible solutions

    NARCIS (Netherlands)

    Vijverberg, J.; Dejen, E.; Getahun, A.; Nagelkerke, L.A.J.

    2012-01-01

    Fish populations of nine Ethiopian freshwater lakes were quantitatively sampled with a standardized protocol, using multi-mesh gill nets. In total, 27 species were identified, but only 14 species were common. Based on the common species, the fish communities showed large differences in their species

  17. Tropical coastal habitats as surrogates of fish community structure, grazing, and fisheries value.

    Science.gov (United States)

    Harborne, Alastair R; Mumby, Peter J; Kappel, Carrie V; Dahlgren, Craig P; Micheli, Fiorenza; Holmes, Katherine E; Brumbaugh, Daniel R

    2008-10-01

    Habitat maps are frequently invoked as surrogates of biodiversity to aid the design of networks of marine reserves. Maps are used to maximize habitat heterogeneity in reserves because this is likely to maximize the number of species protected. However, the technique's efficacy is limited by intra-habitat variability in the species present and their abundances. Although communities are expected to vary among patches of the same habitat, this variability is poorly documented and rarely incorporated into reserve planning. To examine intra-habitat variability in coral-reef fishes, we generated a data set from eight tropical coastal habitats and six islands in the Bahamian archipelago using underwater visual censuses. Firstly, we provide further support for habitat heterogeneity as a surrogate of biodiversity as each predefined habitat type supported a distinct assemblage of fishes. Intra-habitat variability in fish community structure at scales of hundreds of kilometers (among islands) was significant in at least 75% of the habitats studied, depending on whether presence/absence, density, or biomass data were used. Intra-habitat variability was positively correlated with the mean number of species in that habitat when density and biomass data were used. Such relationships provide a proxy for the assessment of intra-habitat variability when detailed quantitative data are scarce. Intra-habitat variability was examined in more detail for one habitat (forereefs visually dominated by Montastraea corals). Variability in community structure among islands was driven by small, demersal families (e.g., territorial pomacentrid and labrid fishes). Finally, we examined the ecological and economic significance of intra-habitat variability in fish assemblages on Montastraea reefs by identifying how this variability affects the composition and abundances of fishes in different functional groups, the key ecosystem process of parrotfish grazing, and the ecosystem service of value of

  18. Fishing

    Institute of Scientific and Technical Information of China (English)

    姜群山

    2002-01-01

    @@ Last Saturday my cousin (表兄) came to my home. We were very happy to see each other. We decided that the next day we went to fish. We got up very early that day. When we left home,the moon could still be seen in the sky.

  19. Mineralization Of PAHs In Coal-Tar Impacted Aquifer Sediments And Associated Microbial Community Structure Investigated With FISH

    Science.gov (United States)

    The microbial community structure and mineralization of polycyclic aromatic hydrocarbons (PAHs) in a coal-tar contaminated aquifer were investigated spatially using fluorescence in situ hybridization (FISH) and in laboratory-scale incubations of the aquifer sediments. DAPI-detect...

  20. Baseline assessment of fish communities of the Flower Garden Banks (2010 - 2013) using technical diving operations: 2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The proposed work develop baseline information on fish and benthic communities within the Flower Garden Banks National Marine Sanctuary (FGBNMS). Surveys will...

  1. Baseline assessment of fish communities of the Flower Garden Banks (2010 - 2013) using technical diving operations: 2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The proposed work develop baseline information on fish and benthic communities within the Flower Garden Banks National Marine Sanctuary (FGBNMS). Surveys will employ...

  2. A Devonian predatory fish provides insights into the early evolution of modern sarcopterygians

    Science.gov (United States)

    Lu, Jing; Zhu, Min; Ahlberg, Per Erik; Qiao, Tuo; Zhu, You’an; Zhao, Wenjin; Jia, Liantao

    2016-01-01

    Crown or modern sarcopterygians (coelacanths, lungfishes, and tetrapods) differ substantially from stem sarcopterygians, such as Guiyu and Psarolepis, and a lack of transitional fossil taxa limits our understanding of the origin of the crown group. The Onychodontiformes, an enigmatic Devonian predatory fish group, seems to have characteristics of both stem and crown sarcopterygians but is difficult to place because of insufficient anatomical information. We describe the new skull material of Qingmenodus, a Pragian (~409-million-year-old) onychodont from China, using high-resolution computed tomography to image internal structures of the braincase. In addition to its remarkable similarities with stem sarcopterygians in the ethmosphenoid portion, Qingmenodus exhibits coelacanth-like neurocranial features in the otic region. A phylogenetic analysis based on a revised data set unambiguously assigns onychodonts to crown sarcopterygians as stem coelacanths. Qingmenodus thus bridges the morphological gap between stem sarcopterygians and coelacanths and helps to illuminate the early evolution and diversification of crown sarcopterygians. PMID:27386576

  3. Evolution of ontogenetic dietary shifts and associated gut features in prickleback fishes (Teleostei: Stichaeidae).

    Science.gov (United States)

    German, D P; Gawlicka, A K; Horn, M H

    2014-02-01

    We tested the hypothesis that an ontogenetic dietary shift from carnivory to herbivory or omnivory, and concomitant changes in the gut facilitating digestion of algae, are synapomorphies of the tribes Xiphisterini and Esselenichthyini in the family Stichaeidae (pricklebacks). Previous investigations have revealed that two xiphisterine pricklebacks-Xiphister mucosus and Xiphister atropurpureus-become herbivorous or omnivorous, respectively, as their bodies grow larger, and that their guts show related changes in length and function. In this study we found that, with increase in size, the basal member of the Xiphisterini, Phytichthys chirus, showed an increased proportion of algae in its diet, increased activity of α-amylase and decreased activity of aminopeptidase, all of which support the synapomorphy hypothesis. Cebidichthys violaceus, a herbivore in the Esselenichthyini, shows similar ontogenetic changes in diet and digestive tract length and physiology, but these features were not observed in two derived carnivores, Dictyosoma burgeri and Dictyosoma rubrimaculatum, within the clade. These results suggest that herbivory is isolated to C. violaceus within the Esselenichthyini. Allometric relationships of gut length as a function of body size generally follow diet within the Xiphisterini and Esselenichthyini, with herbivores having the longest guts, which become disproportionately longer than body size as the fishes grow, omnivores intermediate gut lengths, and carnivores the shortest. A carnivore from an adjacent clade, Anoplarchus purpurescens, had the shortest gut, which did not change in length relative to body length as the fish grew. Overall, our results clarify the patterns of dietary evolution within the Stichaeidae and lay the foundation for more detailed studies of dietary and digestive specialization in fishes in the family.

  4. Spatial and temporal variation in fish community of the Ria de Aveiro estuarine lagoon (Portugal.

    Directory of Open Access Journals (Sweden)

    Eva García-Seoane

    2015-11-01

    Full Text Available Fish assemblages of Ria de Aveiro coastal lagoon (Northwest Portugal were studied from February 2012 and January 2013. Sampling were monthly conducted with a traditional beach-seine net (“chincha” at 9 sites. Multivariate approach were used in order to analyse the spatial and temporal variation in fish community. A total of 58,201 fishes, weighting 249,540 g, were identified, representing 37 taxa and 21 families. Four taxa (Atherina spp., Dicentrarchus labrax, Liza spp., and Sardina pilchardus were responsible for 94.7% and 85.4% of the total abundance, in number and weight. There were significant differences in fish community, in terms of fish number and weight, between sites and between months (ANOSIM, p<0.01. A total of 12 species appeared as characteristics of one of more sampling sites either in terms of number and weight. In both cases, D. labrax, Liza spp. and Atherina spp. were typical throughout the study area. Other species, such as Spondyliosoma cantharus appeared as typical only in the part of the lagoon more influenced by marine waters, whereas Anguilla anguilla was typical of the inner area. A total of 11 (in number or 13 (in weight species appeared as typical of at least one month of the year. Liza spp. and Atherina spp. were typical all the year round for number and weight data. In both cases, D. labrax, Diplodus spp. and S. pilchardus, appeared as a typical from spring to autumn. The number of typical species varied with the season, being maximum in May and minimum in winter. Finally, results of this work were discussed in comparison to previous studies.

  5. Red Lionfish (Pterois volitans Invade San Salvador, Bahamas: No Early Effects on Coral and Fish Communities

    Directory of Open Access Journals (Sweden)

    Alexander, Amanda K.

    2011-10-01

    Full Text Available Biological invaders are a leading contributor to global losses of biodiversity. A recent invader to the waters surrounding San Salvador, Bahamas, the red lionfish, Pterois volitans, was first reported in 2006; by 2009 they were common in waters 2-40 m deep around the island. Our study collected data on coral communities and fish assemblages at three patch reef complexes (Rice Bay, Rocky Point, Lindsay Reef in 2007, during the initial phase of the invasion, and compared the results to a nearly identical study done in 2001 before P. volitans colonized San Salvador. Prey selection and quantity of consumption by P. volitans were also examined. Coral and fish species richness, diversity, percent cover (corals and abundance (fish were similar in 2001 and 2007. Of the 5,078 fish recorded during our study on shallow patch reefs, only two were P. volitans, but they were more prevalent in deeper water along San Salvador’s “wall.” Captured P. volitans ranged in size from 19-32 cm, all longer than maturity length. Pallid goby (Coryphopterus eidolon, black cap basslet (Gramma melacara and red night shrimp (Rynchocienetes rigens were the most commonly identified stomach contents. The effects of the successful invasion and increasing population of P. volitans on San Salvador’s reef ecosystem are uncertain at this time; future monitoring of potential changes in coral and fish communities on the patch reefs of San Salvador is recommended to determine if population control measures need to be considered. Initial post-invasion data (2007, along with pre-invasion data (2001, are valuable benchmarks for future studies.

  6. Computational modeling of electric imaging in weakly electric fish: insights for physiology, behavior and evolution.

    Science.gov (United States)

    Gómez-Sena, Leonel; Pedraja, Federico; Sanguinetti-Scheck, Juan I; Budelli, Ruben

    2014-01-01

    Weakly electric fish can sense electric signals produced by other animals whether they are conspecifics, preys or predators. These signals, sensed by passive electroreception, sustain electrocommunication, mating and agonistic behavior. Weakly electric fish can also generate a weak electrical discharge with which they can actively sense the animate and inanimate objects in their surroundings. Understanding both sensory modalities depends on our knowledge of how pre-receptorial electric images are formed and how movements modify them during behavior. The inability of effectively measuring pre-receptorial fields at the level of the skin contrasts with the amount of knowledge on electric fields and the availability of computational methods for estimating them. In this work we review past work on modeling of electric organ discharge and electric images, showing the usefulness of these methods to calculate the field and providing a brief explanation of their principles. In addition, we focus on recent work demonstrating the potential of electric image modeling and what the method has to offer for experimentalists studying sensory physiology, behavior and evolution.

  7. Importance of Natural and Anthropogenic Environmental Factors to Fish Communities of the Fox River in Illinois

    Science.gov (United States)

    Schnier, Spencer; Cai, Ximing; Cao, Yong

    2016-02-01

    The dominant environmental determinants of aquatic communities have been a persistent topic for many years. Interactions between natural and anthropogenic characteristics within the aquatic environment influence fish communities in complex ways that make the effect of a single characteristic difficult to ascertain. Researchers are faced with the question of how to deal with a large number of variables and complex interrelationships. This study utilized multiple approaches to identify key environmental variables to fish communities of the Fox River Basin in Illinois: Pearson and Spearman correlations, an algorithm based on information theory called mutual information, and a measure of variable importance built into the machine learning algorithm Random Forest. The results are based on a dataset developed for this study, which uses a fish index of biological integrity (IBI) and its ten component metrics as response variables and a range of environmental variables describing geomorphology, stream flow statistics, climate, and both reach-scale and watershed-scale land use as independent variables. Agricultural land use and the magnitude and duration of low flow events were ranked by the algorithms as key factors for the study area. Reach-scale characteristics were dominant for native sunfish, and stream flow metrics were rated highly for native suckers. Regression tree analyses of environmental variables on fish IBI identified breakpoints in percent agricultural land in the watershed (~64 %), duration of low flow pulses (~12 days), and 90-day minimum flow (~0.13 cms). The findings should be useful for building predictive models and design of more effective monitoring systems and restoration plans.

  8. Patterns of fish community composition along a river affected by agricultural and urban disturbance in south-central Chile

    Energy Technology Data Exchange (ETDEWEB)

    Orrego, Rodrigo [University of Ontario Institute of Technology, Oshawa, Ontario; Barra, Ricardo [University of Concepcion, Eula, Chile; Chiang, Gustavo [University of Concepcion, Eula, Chile; Adams, Marshall [ORNL; Gavilan, Juan F. [University of Concepcion, Eula, Chile

    2008-03-01

    Patterns of fish community composition in a south-central Chile river were investigated along the altitudinal-spatial and environmental gradient and as a function of anthropogenic factors. The spatial pattern of fish communities in different biocoenotic zones of the Chillan River is influenced by both natural factors such a hydrologic features, habitat, and feeding types, and also by water quality variables which can reduce the diversity and abundance of sensitive species. A principal component analysis incorporating both water quality parameters and biomarker responses of representative fish species was used to evaluate the status of fish communities along the spatial gradient of the stream. The abundance and diversity of the fish community changed from a low in the upper reaches where the low pollution-tolerant species such as salmonid dominated, to a reduced diversity in the lower reaches of the river where tolerant browser species such as cypriniformes dominated. Even though the spatial pattern of fish community structure is similar to that found for the Chilean Rivers, the structure of these communities is highly influenced by human disturbance, particularly along the lower reaches of the river.

  9. An expanded map of vegetation communities at Big Muddy National Fish and Wildlife Refuge

    Science.gov (United States)

    Struckhoff, Matthew A.

    2013-01-01

    In 2012, a map of vegetation communities on Big Muddy National Fish and Wildlife Refuge was expanded based on interpretation of aerial photographs and field data. National Agricultural Imagery Program aerial photographs were used to identify distinct communities on previously unmapped refuge units and newly acquired parcels. Newly mapped polygons were then visited to adjust map boundaries, classify communities according to the National Vegetation Classification System, and quantify the abundance of dominant species and non-native, invasive species of concern to the refuge and other resource management agencies along the Missouri River. The expanded map now covers 6,136 hectares representing 33 community types, including 6 previously unmapped types. The full map includes 1,113 polygons, of which 627 are new, 21 are updated from the 2009 mapping effort, and 465 are unchanged from 2009. Mortality of primarily cottonwood stems, because of growing-season floods between 2008 and 2011, has reduced foliar cover of woody stems and created more open wooded communities. In herbaceous communities, dominance by herbaceous old fields has increased due to the inclusion of refuge units dominated by lands in recent agricultural production in the expanded map. Wetland community abundance has increased slightly due to recent flooding.

  10. The Adaptation of Fishing Instruments by a Farmers' Community in the Thung Kula Area, in North Eastern Thailand

    Directory of Open Access Journals (Sweden)

    Worawan Ubonlert

    2009-01-01

    Full Text Available Problem statement: In a historical study of the ancient communities in the area of Thung Kula, it was revealed that there are important resources including rice, fish, salt and iron. Salt is used in making fermented fish (known locally as Pla Daek, a culinary culture which has been prevalent in the ethnic groups of Laos and Khmer. The availability of rice and fish in Thung Kula has continued to this day. Thung Kula farmers have extended their fishing sources from the government-owned places to their own fields or ponds. Approach: They use fishing instruments that had been developed out of folk wisdom in combination with the new technology in order to increase the fishing yields adequate for their own consumption and for commerce. The present research aimed to study the adaptation of fishing instruments of the farmers at Ban Ta Yuak, Thung Luang sub-district, Suwannaphum district, Roi-Et province. The studied area was Thung Kula in the North East of Thailand. The research method was qualitative. Data were collected from relevant documents and from field studies with 25 informants. Structured and unstructured interviews were conducted with local tradesmen, consumers, fishing-instrument shop owners. Results: The results were presented descriptively below. The adaptation of fishing instruments of Ban Ta Yuak farmers began with the increased population, the changing ecological systems as a result of the government’s construction of reservoirs, canals, public ponds and the market-oriented economy which had attracted the local fishing markets across the Thung Kula area. Ban Ta Yuak farmers have then adapted their fishing instruments to fit the available kinds of fish and the ecological systems of the local water sources. With assistance from the government, the farmers have their own fishing ponds. It was found that prior to the application of the national economic and social plan of 1962 these farmers created simple fishing instruments such as Sai (a

  11. Ecomorphology as a predictor of fish diet: a case study on the North Sea benthic fish community

    NARCIS (Netherlands)

    Diderich, W.P.

    2006-01-01

    A methodological approach based on fish ecomorphology was chosen to predict potential fish diet. This study tests a method used in earlier research on a marine ecosystem containing phylogenetically diverse organisms: the North Sea. Fish feeding morphology imposes constraints on feeding options. A bo

  12. Assessing the effect of marine reserves on household food security in Kenyan coral reef fishing communities.

    Science.gov (United States)

    Darling, Emily S

    2014-01-01

    Measuring the success or failure of natural resource management is a key challenge to evaluate the impact of conservation for ecological, economic and social outcomes. Marine reserves are a popular tool for managing coastal ecosystems and resources yet surprisingly few studies have quantified the social-economic impacts of marine reserves on food security despite the critical importance of this outcome for fisheries management in developing countries. Here, I conducted semi-structured household surveys with 113 women heads-of-households to investigate the influence of two old, well-enforced, no-take marine reserves on food security in four coastal fishing communities in Kenya, East Africa. Multi-model information-theoretic inference and matching methods found that marine reserves did not influence household food security, as measured by protein consumption, diet diversity and food coping strategies. Instead, food security was strongly influenced by fishing livelihoods and household wealth: fishing families and wealthier households were more food secure than non-fishing and poorer households. These findings highlight the importance of complex social and economic landscapes of livelihoods, urbanization, power and gender dynamics that can drive the outcomes of marine conservation and management.

  13. Assessing the effect of marine reserves on household food security in Kenyan coral reef fishing communities.

    Directory of Open Access Journals (Sweden)

    Emily S Darling

    Full Text Available Measuring the success or failure of natural resource management is a key challenge to evaluate the impact of conservation for ecological, economic and social outcomes. Marine reserves are a popular tool for managing coastal ecosystems and resources yet surprisingly few studies have quantified the social-economic impacts of marine reserves on food security despite the critical importance of this outcome for fisheries management in developing countries. Here, I conducted semi-structured household surveys with 113 women heads-of-households to investigate the influence of two old, well-enforced, no-take marine reserves on food security in four coastal fishing communities in Kenya, East Africa. Multi-model information-theoretic inference and matching methods found that marine reserves did not influence household food security, as measured by protein consumption, diet diversity and food coping strategies. Instead, food security was strongly influenced by fishing livelihoods and household wealth: fishing families and wealthier households were more food secure than non-fishing and poorer households. These findings highlight the importance of complex social and economic landscapes of livelihoods, urbanization, power and gender dynamics that can drive the outcomes of marine conservation and management.

  14. Application of exploratory factor analysis to assess fish consumption in a university community

    Directory of Open Access Journals (Sweden)

    Erika da Silva Maciel

    2013-03-01

    Full Text Available The objective of this research was to use the technique of Exploratory Factor Analysis (EFA for the adequacy of a tool for the assessment of fish consumption and the characteristics involved in this process. Data were collected during a campaign to encourage fish consumption in Brazil with the voluntarily participation of members of a university community. An assessment instrument consisting of multiple-choice questions and a five-point Likert scale was designed and used to measure the importance of certain attributes that influence the choice and consumption of fish. This study sample was composed of of 224 individuals, the majority were women (65.6%. With regard to the frequency of fish consumption, 37.67% of the volunteers interviewed said they consume the product two or three times a month, and 29.6% once a week. The Exploratory Factor Analysis (EFA was used to group the variables; the extraction was made using the principal components and the rotation using the Quartimax method. The results show clusters in two main constructs, quality and consumption with Cronbach Alpha coefficients of 0.75 and 0.69, respectively, indicating good internal consistency.

  15. Assessing the Effect of Marine Reserves on Household Food Security in Kenyan Coral Reef Fishing Communities

    Science.gov (United States)

    Darling, Emily S.

    2014-01-01

    Measuring the success or failure of natural resource management is a key challenge to evaluate the impact of conservation for ecological, economic and social outcomes. Marine reserves are a popular tool for managing coastal ecosystems and resources yet surprisingly few studies have quantified the social-economic impacts of marine reserves on food security despite the critical importance of this outcome for fisheries management in developing countries. Here, I conducted semi-structured household surveys with 113 women heads-of-households to investigate the influence of two old, well-enforced, no-take marine reserves on food security in four coastal fishing communities in Kenya, East Africa. Multi-model information-theoretic inference and matching methods found that marine reserves did not influence household food security, as measured by protein consumption, diet diversity and food coping strategies. Instead, food security was strongly influenced by fishing livelihoods and household wealth: fishing families and wealthier households were more food secure than non-fishing and poorer households. These findings highlight the importance of complex social and economic landscapes of livelihoods, urbanization, power and gender dynamics that can drive the outcomes of marine conservation and management. PMID:25422888

  16. A sensory bias has triggered the evolution of egg-spots in cichlid fishes.

    Directory of Open Access Journals (Sweden)

    Bernd Egger

    Full Text Available Although, generally, the origin of sex-limited traits remains elusive, the sensory exploitation hypothesis provides an explanation for the evolution of male sexual signals. Anal fin egg-spots are such a male sexual signal and a key characteristic of the most species-rich group of cichlid fishes, the haplochromines. Males of about 1500 mouth-brooding species utilize these conspicuous egg-dummies during courtship--apparently to attract females and to maximize fertilization success. Here we test the hypothesis that the evolution of haplochromine egg-spots was triggered by a pre-existing bias for eggs or egg-like coloration. To this end, we performed mate-choice experiments in the basal haplochromine Pseudocrenilabrus multicolor, which manifests the plesiomorphic character-state of an egg-spot-less anal fin. Experiments using computer-animated photographs of males indeed revealed that females prefer images of males with virtual ('in-silico' egg-spots over images showing unaltered males. In addition, we tested for color preferences (outside a mating context in a phylogenetically representative set of East African cichlids. We uncovered a strong preference for yellow, orange or reddish spots in all haplochromines tested and, importantly, also in most other species representing more basal lines. This pre-existing female sensory bias points towards high-quality (carotenoids-enriched food suggesting that it is adaptive.

  17. Abyssal Scavenging Communities attracted to Sargassum and fish in the Sargasso Sea

    Science.gov (United States)

    Fleury, Aharon G.; Drazen, Jeffrey C.

    2013-02-01

    Deep-sea communities rely on epipelagic surface production as a primary source of energy and food. The flux of phytodetritus drives many abyssal ecological processes but the flux of large particles such as nekton carcasses, macroalgae, and wood may also be important. Recent baited camera experiments noted that some abyssal fish consumed spinach and phytoplankton placed on the seafloor. To evaluate if fish or other scavengers would consume natural plant or macroalgal material falling to the deep-sea floor we conducted camera experiments using Sargassum or mackerel bait in the Sargasso Sea. A benthic community of invertebrates was attracted to Sargassum, which naturally falls to the seafloor in this area. In five instances it was observed that an isopod Bathyopsurus sp. removed a piece of Sargassum from the main clump and left the field of view with it. An ophiuroid is also observed handling a piece of Sargassum. The group of scavengers attracted to mackerel bait was very different and was dominated by large ophidiid fish. In contrast to studies elsewhere in the abyssal North Atlantic, only a small number of rattails are observed, which could be related to water depth or an ichthyofaunal zonal change between oligotrophic and eutrophic regions.

  18. Water clarity of the Colorado River—Implications for food webs and fish communities

    Science.gov (United States)

    Voichick, Nicholas; Kennedy, Theodore; Topping, David; Griffiths, Ronald; Fry, Kyrie

    2016-11-01

    The closure of Glen Canyon Dam in 1963 resulted in drastic changes to water clarity, temperature, and flow of the Colorado River in Glen, Marble, and Grand Canyons. The Colorado River is now much clearer, water temperature is less variable throughout the year, and the river is much colder in the summer months. The flow—regulated by the dam—is now less variable annually, but has larger daily fluctuations than during pre-dam times. All of these changes have resulted in a different fish community and different food resources for fish than existed before the dam was built. Recent monitoring of water clarity, by measuring turbidity, has helped scientists and river managers understand modern water-clarity patterns in the dam-regulated Colorado River. These data were then used to estimate pre-dam turbidity in the Colorado River in order to make comparisons of pre-dam and dam-regulated conditions, which are useful for assessing biological changes in the river over time. Prior to dam construction, the large sediment load resulted in low water clarity almost all of the time, a condition which was more favorable for the native fish community.

  19. How Resilient Are Europe’s Inshore Fishing Communities to Change?

    DEFF Research Database (Denmark)

    Hadjimichael, Maria; Delaney, Alyne; J. Kaiser, Michel;

    2013-01-01

    protected as the interests of their offshore counterpart. Decisions and initiatives at global, EU, and sometimes national level, tend to take into account those fisheries sectors which have a national economic importance. A socio-ecological analysis can shift the focus from biological and economic aspects......One would hypothesize that the Common Fisheries Policy, as the umbrella framework for fisheries management in the EU would have the greatest impact on fishers’ communities across Europe. There are, however, biological, economic, social, and political factors, which vary among fishing communities...... that can affect how these communities react to changes. This paper explores the links between institutional arrangements and ecological dynamics in two European inshore fisheries socio-ecological systems, using a resilience framework. The Mediterranean small-scale fishers do not seem to have been...

  20. Characterization of water quality and biological communities, Fish Creek, Teton County, Wyoming, 2007-08

    Science.gov (United States)

    Eddy-Miller, Cheryl A.; Peterson, David A.; Wheeler, Jerrod D.; Leemon, Daniel J.

    2010-01-01

    Fish Creek, a tributary to the Snake River, is about 25 river kilometers long and is located in Teton County in western Wyoming near the town of Wilson. Public concern about nuisance growths of aquatic plants in Fish Creek have been increasing in recent years. To address this concern, the U.S. Geological Survey conducted a study in cooperation with the Teton Conservation District to characterize the water quality and biological communities in Fish Creek. Water-quality samples were collected for analyses of physical properties and water chemistry (nutrients, nitrate isotopes, and wastewater chemicals) between March 2007 and October 2008 from seven surface-water sites and three groundwater wells. During this same period, aquatic plant and macroinvertebrate samples were collected and habitat characteristics were measured at the surface-water sites. The main objectives of this study were to (1) evaluate nutrient concentrations (that influence biological indicators of eutrophication) and potential sources of nutrients by using stable isotope analysis and other indicator chemicals (such as caffeine and disinfectants) that could provide evidence of anthropogenic sources, such as wastewater or septic tank contamination in Fish Creek and adjacent groundwater, and (2) characterize the algal, macrophyte, and macroinvertebrate communities and habitat of Fish Creek. Nitrate was the dominant species of dissolved nitrogen present in all samples and was the only bioavailable species detected at concentrations greater than the laboratory reporting level in all surface-water samples. Average concentrations of dissolved nitrate in surface water were largest in samples collected from the two sites with seasonal flow near Teton Village and decreased downstream; the smallest concentration was at downstream site A-Wck. Concentrations of dissolved nitrate in groundwater were consistently greater than concentrations in corresponding surface-water sites during the same sampling event

  1. Intrasexual competition facilitates the evolution of alternative mating strategies in a colour polymorphic fish

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    Uy J Albert C

    2010-12-01

    Full Text Available Abstract Background Intense competition for access to females can lead to males exploiting different components of sexual selection, and result in the evolution of alternative mating strategies (AMSs. Males of Poecilia parae, a colour polymorphic fish, exhibit five distinct phenotypes: drab-coloured (immaculata, striped (parae, structural-coloured (blue and carotenoid-based red and yellow morphs. Previous work indicates that immaculata males employ a sneaker strategy, whereas the red and yellow morphs exploit female preferences for carotenoid-based colours. Mating strategies favouring the maintenance of the other morphs remain to be determined. Here, we report the role of agonistic male-male interactions in influencing female mating preferences and male mating success, and in facilitating the evolution of AMSs. Results Our study reveals variation in aggressiveness among P. parae morphs during indirect and direct interactions with sexually receptive females. Two morphs, parae and yellow, use aggression to enhance their mating success (i.e., number of copulations by 1 directly monopolizing access to females, and 2 modifying female preferences after winning agonistic encounters. Conversely, we found that the success of the drab-coloured immaculata morph, which specializes in a sneak copulation strategy, relies in its ability to circumvent both male aggression and female choice when facing all but yellow males. Conclusions Strong directional selection is expected to deplete genetic variation, yet many species show striking genetically-based polymorphisms. Most studies evoke frequency dependent selection to explain the persistence of such variation. Consistent with a growing body of evidence, our findings suggest that a complex form of balancing selection may alternatively explain the evolution and maintenance of AMSs in a colour polymorphic fish. In particular, this study demonstrates that intrasexual competition results in phenotypically distinct

  2. Abrupt shifts in the fish community of the hydrologically variable upper estuary of the Swan River

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    Kanandjembo, A. N.; Potter, I. C.; Platell, M. E.

    2001-09-01

    Fish were sampled in nearshore, shallow waters (fish species caught during the study spawn in the upper estuaries. These species, which include the semi-anadromous Nematalosa vlaminghi, comprised 50·0% of the number of species and 88·8% of the number of fish in shallow waters and 43·8 and 89·9%, respectively, of those in deeper waters. The two most abundant species in shallow waters, Engraulis australis and N. vlaminghi, contributed 36·0 and 19·6%, respectively, to the total numbers of fish in those waters, and the latter species comprised nearly 50% of the catch in deeper waters. During winter, when freshwater discharge increased sharply and salinities declined precipitously, the number of species and abundance of fish in shallow and deeper waters were generally at their lowest and the species composition was the most discrete. This reflected the downstream movement out of the upper estuary of substantial numbers of individuals of species such as N. vlaminghi, Acanthopagrus butcheri, Amniataba caudavittata, Atherinomorus ogilbyi, Atherinosoma elongata and Craterocephalus mugiloides and the upstream movement into the upper estuary of juvenile Mugil cephalus. The overall fish fauna then changed quite abruptly in spring, when large N. vlaminghi, A. butcheri and A. caudavittata became abundant as they migrated into the upper estuary where they then spawned. During summer and autumn, the fauna in the shallows then changed more gradually through, inter alia, the recruitment of juvenile fish community in winter contrasts with the gradual, cyclical changes undergone during the year by the ichthyofaunas of holarctic, macrotidal estuaries, such as the Severn Estuary in the UK, in which the hydrology does not undergo such sudden, extreme seasonal changes and the ichthyofauna is dominated by marine and diadromous species that each enter the estuary at specific, but varying times of the year. Differences between the fish faunas of the shallow waters of the Swan and

  3. Expanding perceptions of subsistence fish consumption: evidence of high commercial fish consumption and dietary mercury exposure in an urban coastal community.

    Science.gov (United States)

    Holloman, Erica L; Newman, Michael C

    2012-02-01

    Through collaborative partnerships established between current researchers and The Moton Community House (a local community center), African American women (ages 16-49yrs) from the Southeast Community of Newport News, Virginia, USA were surveyed to assess the reproducibility and consistency of fish consumption patterns (ingestion rates, exposure frequencies, weight, and fish consumption rates) derived from a community-specific fish consumption survey. Women were also surveyed to assess the reliability of the survey responses, and to estimate daily mercury intake. Fish consumption patterns were reproducible and the survey responses were reliable. Comparison between years revealed that fish consumption patterns remained consistent over time. In addition, the high fish consumption rate estimated in 2008 (147.8g/day; 95% CI: 117.6-185.8g/day) was confirmed with a rate (134.9g/day; 95% CI: 88-207g/day) not materially different and still considerably higher than mean fish consumption rates reported for U.S. women. Daily mercury intake rates were estimated using consumption data from 2008 and three consumption scenarios (canned white, canned light, and no tuna) due to confirmed differences in mercury concentration between canned white and light tuna. Arithmetic mean daily mercury intake rates were 0.284μg/kg bw/day (95% CI: 0.229-0.340μg/kg bw/day) using canned white tuna, 0.212μg/kg bw/day (95% CI: 0.165-0.259μg/kg bw/day) using light tuna, and 0.197μg/kg bw/day (95% CI: 0.151-0.243μg/kg bw/day) using no tuna. Approximately 58%-73% of the daily mercury intake rates for African American women in the Southeast Community exceeded US EPA's oral reference dose (RfD) of 0.10μg/kg bw/day for mercury. In addition, 2% of the rates exceeded a level (1.00μg/kg bw/day) documented to produce adverse health effects. Past and current investigations confirmed that even though women in this community were not subsistence fishers, they are subsistence fish consumers.

  4. Permian-Triassic Osteichthyes (bony fishes): diversity dynamics and body size evolution.

    Science.gov (United States)

    Romano, Carlo; Koot, Martha B; Kogan, Ilja; Brayard, Arnaud; Minikh, Alla V; Brinkmann, Winand; Bucher, Hugo; Kriwet, Jürgen

    2016-02-01

    significant reduction in osteichthyan body size. Neopterygii, the clade that encompasses the vast majority of extant fishes, underwent another diversification phase in the Late Triassic. The Triassic radiation of Osteichthyes, predominantly of Actinopterygii, which only occurred after severe extinctions among Chondrichthyes during the Middle-Late Permian, resulted in a profound change within global fish communities, from chondrichthyan-rich faunas of the Permo-Carboniferous to typical Mesozoic and Cenozoic associations dominated by actinopterygians. This turnover was not sudden but followed a stepwise pattern, with leaps during extinction events.

  5. Long Term Effect of Cyprinid Fishes on Phytoplankton and Zooplankton Communities in a Shallow Water Protection Reservoir

    Science.gov (United States)

    Mátyás, Kálmán; Korponai, János; Tátrai, István; Paulovits, Gábor

    2004-01-01

    The effects of fish kill and different fish stocks on the phytoplankton and zooplankton dynamics were studied in a shallow hypertrophic reservoir system. When fish stock was below 100 kg ha-1, nutrient availability was not the main limiting factor for growth of phytoplankton. Consequently top-down forces controlled phytoplankton. In the years with high fish stock (>100 kg ha-1) the bottom-up forces dominated as nutrient availability was the main limiting factor for growth of phytoplankton. We can conclude that significant water quality improvement can be achieved in the reservoir system by decreasing fish stock below 100 kg ha-1. Although clear-water phase could be stabilised temporary by macrophytes, stabilisation of good water quality requires continuous regulation of fish community. (

  6. Application of AI on exploring the relationship between fish community and water quality

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    Tsai, Wen-Ping; Chang, Fi-John

    2016-04-01

    Subject to the geographic environment and climatic conditions of Taiwan, rivers in Taiwan are of steep slopes and flow into oceans very quickly. Due to the severe intensity and short duration of typhoons and storms, sudden rainfall would easily cause huge variations and significant impacts on riverine eco-hydrological environments. To make an effective and comprehensive assessment for sustainable water resources management, this study aims to investigate the relationship between river flow and water quality on fish communities in order to comprehend the situations of the eco-hydrological system in this river basin. We collect a complete set of observational heterogeneity data, which include water quality parameters, stream flow and fish species in the Danshui River of northern Taiwan. This study attempts to improve the understanding of the relationship between water quality parameters, flow regime and fish species by using artificial neural networks (ANNs). The Self-organizing feature map (SOM) is an unsupervised learning algorithm used to cluster, analyze and visualize a large number of data. The results of map size selection for the SOM show that nine clusters (3x3) form the optimum map size based on the local minimum values of both quantization error (QE) and topographic error (TE). The clustering results demonstrate that the SOM is capable of clustering the datasets suitably and can be considered as a powerful tool for further exploration of the relationship between water quality parameters and fish species. It is noted that according to the results of the structure index, the representative indicators of water quality parameters and fish species in the Dahan River, the main tributary of the Danshui River, consist of dissolved oxygen (DO), total phosphorus (TP), water temperature, Onychostoma barbatulum, Rhinogobius candidianus, Unidentified Opsariichthys/Zacco spp., Formosania lacustre, Candidia barbata and Hemimyzon formosanus, respectively. The results of

  7. Assessing the efficacy of single-pass backpack electrofishing to characterize fish community structure

    Science.gov (United States)

    Meador, M.R.; McIntyre, J.P.; Pollock, K.H.

    2003-01-01

    Two-pass backpack electrofishing data collected as part of the U.S. Geological Survey's National Water-Quality Assessment Program were analyzed to assess the efficacy of single-pass backpack electrofishing. A two-capture removal model was used to estimate, within 10 river basins across the United States, proportional fish species richness from one-pass electrofishing and probabilities of detection for individual fish species. Mean estimated species richness from first-pass sampling (p??s1) ranged from 80.7% to 100% of estimated total species richness for each river basin, based on at least seven samples per basin. However, p??s1 values for individual sites ranged from 40% to 100% of estimated total species richness. Additional species unique to the second pass were collected in 50.3% of the samples. Of these, cyprinids and centrarchids were collected most frequently. Proportional fish species richness estimated for the first pass increased significantly with decreasing stream width for 1 of the 10 river basins. When used to calculate probabilities of detection of individual fish species, the removal model failed 48% of the time because the number of individuals of a species was greater in the second pass than in the first pass. Single-pass backpack electrofishing data alone may make it difficult to determine whether characterized fish community structure data are real or spurious. The two-pass removal model can be used to assess the effectiveness of sampling species richness with a single electrofishing pass. However, the two-pass removal model may have limited utility to determine probabilities of detection of individual species and, thus, limit the ability to assess the effectiveness of single-pass sampling to characterize species relative abundances. Multiple-pass (at least three passes) backpack electrofishing at a large number of sites may not be cost-effective as part of a standardized sampling protocol for large-geographic-scale studies. However, multiple

  8. Factors of ecologic succession in oligotrophic fish communities of the Laurentian Great Lakes

    Science.gov (United States)

    Smith, Stanford H.

    1972-01-01

    Oligotrophic fish communities of the Great Lakes have undergone successive disruptions since the mid-1800s. Major contributing factors have been intensive selective fisheries, extreme modification of the drainage, invasion of marine species, and progressive physical–chemical changes of the lake environments. Lake Ontario was the first to be affected as its basin was settled and industrialized earliest, and it was the first to be connected by canals to the mid-Atlantic where the alewife (Alosa pseudoharengus) and sea lamprey (Petromyzon marinus) which ultimately became established in the Great Lakes were abundant. Oligotrophic fish communities were successively disrupted in Lakes Erie, Huron, Michigan, and Superior as the affects of population growth, industrialization, and marine invaders spread upward in the Laurentian drainage.The degree and sequence of response of families offish and species within families differed for each factor, but the sequence of change among families and species has been the same in response to each factor as it affected various lakes at different times. The ultimate result of the disruption of fish communities has been a reduction of productivity of oligotrophic species that ranges from extreme in Lake Ontario to moderate in Lake Superior, and which has reached a state of instability and rapid change in the upper three Great Lakes by the rnid-1900s similar to the situation in Lake Ontario in the mid-1800s. Since oligotrophic species (primarily salmonines, coregonines, and deepwater cottids) are the only kinds of fish that fully occupied the entire volume of the deepwater Great Lakes (Ontario, Huron, Michigan, and Superior), the fish biomass of these lakes has been reduced as various species declined or disappeared. In Lake Erie, which is shallow, and in the shallow bays of the deep lakes, oligotrophic species were replaced by mesotrophic species, primarily percids, which have successively increased and declined. All oligotrophic

  9. Seasonal variation and community structure of fishes in the Mahananda River with special reference to conservation issues

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    Shams Muhammad Galib

    2016-04-01

    Full Text Available This study was carried out in the Mahananda River from January to December 2013 with a view to determining the seasonal variation and community structure of fishes along with some conservation issues. Monthly sampling was carried out using traditional fishing gears and fishes were identified based on morphometric and meristic characters. A total of 4082 individuals of native fish species were captured, analyzed and classified into 62 species belonging to 46 genera, 25 families and 9 orders. Cypriniformes and Siluriformes were the dominant fish orders represented by 19 species each and the most abundant family was Cyprinidae (14 species. In addition to indigenous individuals, 9 individuals of 2 exotic fish species (Hypophthalmichthys molitrix and Pangasius hypophthalmus were also recorded. Among three sampling sites, S-1 was the most diversified in terms of not only the number of individual fish but also the number of species present represented by mean (±SE individuals of 151.50±25.22 and species of 25.58±3.91. Three distinct fish groups of fish families were revealed from the cluster analysis of similarity. To improve the situation, control of illegal fishing gears, establishment of sanctuaries and legal protection for threatened species are recommended.

  10. Evolution of Innate Immunity: Clues from Invertebrates via Fish to Mammals.

    Science.gov (United States)

    Buchmann, Kurt

    2014-01-01

    and functions from their ancestors can be found. They exhibit numerous variants of innate recognition and effector molecules, which allow fast and innate responses toward diverse pathogens despite lack of adaptive responses. The primitive vertebrates (agnathans also termed jawless fish) were the first to supplement innate responses with adaptive elements. Thus hagfish and lampreys use LRRs as variable lymphocyte receptors, whereas higher vertebrates [cartilaginous and bony fishes (jawed fish), amphibians, reptiles, birds, and mammals] developed the major histocompatibility complex, T-cell receptors, and B-cell receptors (immunoglobulins) as additional adaptive weaponry to assist innate responses. Extensive cytokine networks are recognized in fish, but related signal molecules can be traced among invertebrates. The high specificity, antibody maturation, immunological memory, and secondary responses of adaptive immunity were so successful that it allowed higher vertebrates to reduce the number of variants of the innate molecules originating from both invertebrates and lower vertebrates. Nonetheless, vertebrates combine the two arms in an intricate inter-dependent network. Organisms at all developmental stages have, in order to survive, applied available genes and functions of which some may have been lost or may have changed function through evolution. The molecular mechanisms involved in evolution of immune molecules, might apart from simple base substitutions be as diverse as gene duplication, deletions, alternative splicing, gene recombination, domain shuffling, retrotransposition, and gene conversion. Further, variable regulation of gene expression may have played a role.

  11. Planktivory in the changing Lake Huron zooplankton community: Bythotrephes consumption exceeds that of Mysis and fish

    Science.gov (United States)

    Bunnell, D.B.; Davis, B.M.; Warner, D.M.; Chriscinske, M.A.; Roseman, E.F.

    2011-01-01

    Oligotrophic lakes are generally dominated by calanoid copepods because of their competitive advantage over cladocerans at low prey densities. Planktivory also can alter zooplankton community structure. We sought to understand the role of planktivory in driving recent changes to the zooplankton community of Lake Huron, a large oligotrophic lake on the border of Canada and the United States. We tested the hypothesis that excessive predation by fish (rainbow smelt Osmerus mordax, bloater Coregonus hoyi) and invertebrates (Mysis relicta, Bythotrephes longimanus) had driven observed declines in cladoceran and cyclopoid copepod biomass between 2002 and 2007. We used a field sampling and bioenergetics modelling approach to generate estimates of daily consumption by planktivores at two 91-m depth sites in northern Lake Huron, U.S.A., for each month, May-October 2007. Daily consumption was compared to daily zooplankton production. Bythotrephes was the dominant planktivore and estimated to have eaten 78% of all zooplankton consumed. Bythotrephes consumption exceeded total zooplankton production between July and October. Mysis consumed 19% of all the zooplankton consumed and exceeded zooplankton production in October. Consumption by fish was relatively unimportant - eating only 3% of all zooplankton consumed. Because Bythotrephes was so important, we explored other consumption estimation methods that predict lower Bythotrephes consumption. Under this scenario, Mysis was the most important planktivore, and Bythotrephes consumption exceeded zooplankton production only in August. Our results provide no support for the hypothesis that excessive fish consumption directly contributed to the decline of cladocerans and cyclopoid copepods in Lake Huron. Rather, they highlight the importance of invertebrate planktivores in structuring zooplankton communities, especially for those foods webs that have both Bythotrephes and Mysis. Together, these species occupy the epi-, meta- and

  12. Have superfetation and matrotrophy facilitated the evolution of larger offspring in poeciliid fishes?

    Science.gov (United States)

    Olivera-Tlahuel, Claudia; Ossip-Klein, Alison G.; Espinosa-Pérez, Héctor S.; Zúñiga-Vega, J. Jaime

    2015-01-01

    Superfetation is the ability of females to simultaneously carry multiple broods of embryos, with each brood at a different developmental stage. Matrotrophy is the post-fertilization maternal provisioning of nutrients to developing embryos throughout gestation. Several studies have demonstrated that, in viviparous fishes, superfetation and matrotrophy have evolved in a correlated way, such that species capable of bearing several simultaneous broods also exhibit advanced degrees of post-fertilization provisioning. The adaptive value of the concurrent presence of both reproductive modes may be associated with the production of larger newborns, which in turn may result in enhanced offspring fitness. In this study, we tested two hypotheses: (1) species with superfetation and moderate or extensive matrotrophy give birth to larger offspring compared to species without superfetation or matrotrophy; (2) species with higher degrees of superfetation and matrotrophy (i.e. more simultaneous broods and increased amounts of post-fertilization provisioning) give birth to larger offspring compared to species with relatively low degrees of superfetation and matrotrophy (i.e. fewer simultaneous broods and lesser amounts of post-fertilization provisioning). Using different phylogenetic comparative methods and data on 44 species of viviparous fishes of the family Poeciliidae, we found a lack of association between offspring size and the combination of superfetation and matrotrophy. Therefore, the concurrent presence of superfetation and moderate or extensive matrotrophy has not facilitated the evolution of larger offspring. In fact, these traits have evolved differently. Superfetation and matrotrophy have accumulated gradual changes that largely can be explained by Brownian motion, whereas offspring size has evolved fluidly, experiencing changes that likely resulted from selective responses to the local conditions. PMID:26617418

  13. Fish, fish-derived n-3 fatty acids, and risk of incident atrial fibrillation in the Atherosclerosis Risk in Communities (ARIC study.

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    Noelle N Gronroos

    Full Text Available BACKGROUND: Results of observational and experimental studies investigating the association between intake of long-chain n-3 polyunsaturated fatty acids (PUFAs and risk of atrial fibrillation (AF have been inconsistent. METHODS: We studied the association of fish and the fish-derived n-3 PUFAs eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA with the risk of incident AF in individuals aged 45-64 from the Atherosclerosis Risk in Communities (ARIC cohort (n = 14,222, 27% African Americans. Intake of fish and of DHA and EPA were measured via food frequency questionnaire. Plasma levels of DHA and EPA were measured in phospholipids in a subset of participants (n = 3,757. Incident AF was identified through the end of 2008 using ECGs, hospital discharge codes and death certificates. Cox proportional hazards regression was used to estimate hazard ratios of AF by quartiles of n-3 PUFAs or by fish intake. RESULTS: During the average follow-up of 17.6 years, 1,604 AF events were identified. In multivariable analyses, total fish intake and dietary DHA and EPA were not associated with AF risk. Higher intake of oily fish and canned tuna was associated with a nonsignificant lower risk of AF (p for trend = 0.09. Phospholipid levels of DHA+EPA were not related to incident AF. However, DHA and EPA showed differential associations with AF risk when analyzed separately, with lower risk of AF in those with higher levels of DHA but no association between EPA levels and AF risk. CONCLUSIONS: In this racially diverse sample, dietary intake of fish and fish-derived n-3 fatty acids, as well as plasma biomarkers of fish intake, were not associated with AF risk.

  14. Community assembly in Nothobranchius annual fishes: Nested patterns, environmental niche and biogeographic history.

    Science.gov (United States)

    Reichard, Martin; Janáč, Michal; Polačik, Matej; Blažek, Radim; Vrtílek, Milan

    2017-04-01

    The assembly of local communities from regional species pools is shaped by historical aspects of distribution, environmental conditions, and biotic interactions. We studied local community assembly patterns in African annual killifishes of the genus Nothobranchius (Cyprinodontiformes), investigating data from 168 communities across the entire range of regionally co-existing species. Nothobranchius are small fishes associated with annually desiccating pools. We detected a nested pattern of local communities in one region (Southern Mozambique, with Nothobranchius furzeri as the core and dominant species), but no nestedness was found in the second region (Central Mozambique, with Nothobranchius orthonotus being the dominant species). A checkerboard pattern of local Nothobranchius community assembly was demonstrated in both regions. Multivariate environmental niche modeling revealed moderate differences in environmental niche occupancy between three monophyletic clades that largely co-occurred geographically and greater differences between strictly allopatric species within the clades. Most variation among species was observed along an altitudinal gradient; N. furzeri and Nothobranchius kadleci were absent from coastal plains, Nothobranchius pienaari, Nothobranchius rachovii, and Nothobranchius krysanovi were associated with lower altitude and N. orthonotus was intermediate and geographically most widespread species. We discuss implications for ecological and evolutionary research in this taxon.

  15. Fish community of the river Tiber basin (Umbria-Italy: temporal changes and possible threats to native biodiversity

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    Carosi A.

    2015-01-01

    Full Text Available The introduction of exotic fish species in the river Tiber basin has probably caused a serious alteration of original faunal composition. The purpose of this research was to assess the changes occurred over time in the state of the fish communities with particular reference to the reduction of local communities of endemic species. The study area comprised 68 watercourses of the Umbrian portion of the River Tiber basin; the analyses were carried out using the data of the Regional Fish Map of 1st and 2nd level and the 1st update, respectively collected during the periods between the 1990–1996, 2000–2006 and 2007–2014, in 125 sampling stations. The results show a progressive alteration of the fish communities’ structure, as confirmed by the appearance in recent times of new alien species. A total of 40 species was found, only 14 native. The qualitative change of the fish communities appear to be closely related to the longitudinal gradient of the river. The results shows that particularly in the downstream reaches, the combined action of pollution and introduction of exotic species resulted in a gradual decrease in the indigenous component of fish communities. The information collected are the indispensable premise for taking the necessary strategies for conservation of endangered species.

  16. A fish is not a fish: patterns in fatty acid composition of aquatic food may have had implications for hominin evolution.

    Science.gov (United States)

    Joordens, Josephine C A; Kuipers, Remko S; Wanink, Jan H; Muskiet, Frits A J

    2014-12-01

    From c. 2 Ma (millions of years ago) onwards, hominin brain size and cognition increased in an unprecedented fashion. The exploitation of high-quality food resources, notably from aquatic ecosystems, may have been a facilitator or driver of this phenomenon. The aim of this study is to contribute to the ongoing debate on the possible role of aquatic resources in hominin evolution by providing a more detailed nutritional context. So far, the debate has focused on the relative importance of terrestrial versus aquatic resources while no distinction has been made between different types of aquatic resources. Here we show that Indian Ocean reef fish and eastern African lake fish yield on average similarly high amounts of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA). Hence a shift from exploiting tropical marine to freshwater ecosystems (or vice versa) would entail no material difference in dietary long-chain polyunsaturated fatty acid (LC-PUFA) availability. However, a shift to marine ecosystems would likely mean a major increase in access to brain-selective micronutrients such as iodine. Fatty fish from marine temperate/cold waters yield twice as much DHA and four times as much EPA as tropical fish, demonstrating that a latitudinal shift in exploitation of African coastal ecosystems could constitute a significant difference in LC-PUFA availability with possible implications for brain development and functioning. We conclude that exploitation of aquatic food resources could have facilitated the initial moderate hominin brain increase as observed in fossils dated to c. 2 Ma, but not the exceptional brain increase in later stages of hominin evolution. We propose that the significant expansion in hominin brain size and cognition later on may have been aided by strong directional selecting forces such as runaway sexual selection of intelligence, and nutritionally supported by exploitation of high-quality food resources in stable and

  17. New insights on early evolution of spiny-rayed fishes (Teleostei: Acanthomorpha

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    Wei-Jen eChen

    2014-10-01

    Full Text Available The Acanthomorpha is the largest group of teleost fishes with about one third of extant vertebrate species. In the course of its evolution this lineage experienced several episodes of radiation, leading to a large number of descendant lineages differing profoundly in morphology, ecology, distribution and behavior. Although Acanthomorpha was recognized decades ago, we are only now beginning to decipher its large-scale, time-calibrated phylogeny, a prerequisite to test various evolutionary hypotheses explaining the tremendous diversity of this group. In this study, we provide new insights into the early evolution of the acanthomorphs and the euteleost allies based on the phylogenetic analysis of a newly developed dataset combining nine nuclear and mitochondrial gene markers. Our inferred tree is time-calibrated using 15 fossils, some of which have not been used before. While our phylogeny strongly supports a monophyletic Neoteleostei, Ctenosquamata (i.e., Acanthomorpha plus Myctophiformes, and Acanthopterygii, we find weak support (bootstrap value < 48% for the traditionally defined Acanthomorpha, as well as evidence of non-monophyly for the traditional Paracanthopterygii, Beryciformes, and Percomorpha. We corroborate the new Paracanthopterygii sensu Miya et al. (2005 including Polymixiiformes, Zeiformes, Gadiformes, Percopsiformes, and likely the enigmatic Stylephorus chordatus. Our timetree largely agrees with other recent studies based on nuclear loci in inferring an Early Cretaceous origin for the acanthomorphs followed by a Late Cretaceous/Early Paleogene radiation of major lineages. This is in contrast to mitogenomic studies mostly inferring Jurassic or even Triassic ages for the origin of the acanthomorphs. We compare our results to those of previous studies, and attempt to address some of the issues that may have led to incongruence between the fossil record and the molecular clock studies, as well as between the different molecular

  18. Status and trends of the Lake Huron offshore Demersal fish community, 1976-2013

    Science.gov (United States)

    Riley, Stephen C.; Roseman, Edward F.; Chriscinske, Margret Ann; Tucker, Taaja R.; Ross, Jason E.; Armenio, Patricia M.; Watson, Nicole M.; Woelmer, Whitney

    2014-01-01

    The USGS Great Lakes Science Center has conducted trawl surveys to assess annual changes in the offshore demersal fish community of Lake Huron since 1973. Sample sites include five ports in U.S. waters with less frequent sampling near Goderich, Ontario. The 2013 fall bottom trawl survey was carried out between 25 October – 21 November 2013 and included all U.S. ports as well as Goderich, ON. The 2013 main basin prey fish biomass estimate for Lake Huron was 47 kilotonnes, less than half of the estimate in 2012 (97 Kt), and approximately 13 percent of the maximum estimate in the time series. The biomass etimate for YAO alewife in 2013 was lower than in 2012, remained much lower than levels observed before the crash in 2004, and populations were dominated by small fish. Estimated biomass of rainbow smelt also decreased and was the second lowest observed in the time series. Estimated YAO bloater biomass in Lake Huron was also reduced compared to 2012. YOY alewife, rainbow smelt, and bloater abundance and biomass increased over 2012. Biomass estimates for deepwater and slimy sculpins, trout-perch, ninespine stickleback, and round goby in 2013 were lower than in 2012 and remained low compared to historic estimates. Wild juvenile lake trout were captured again in 2013, suggesting that natural reproduction by lake trout continues to occur.

  19. Developing Linkages between Fish Metrics and Fluvial Variation to Explore Responses of Stream Fish Communities to Climate Change across the Conterminous United States

    Science.gov (United States)

    Tsang, Y.; Infante, D.; Wang, L.; Krueger, D. M.; Wieferich, D.

    2011-12-01

    conterminous United States, we then performed a classification to group stream arcs supporting similar fish assemblages and having similar natural characteristics including catchment area, stream reach slope, surficial geology, and the correlated climate variables. Through developed linkages, the identified habitat metrics provided insights on the preference of fish communities, and therefore indicated fish response to potential changes in fluvial conditions at a reach scale. With modeled climate changes, the ecological response could be implied by the relative changes in metrics and in some cases stream class. Assembling this reach-by-reach information, we have the ability to map each reach to projected changes in climate and to understand vulnerability on a regional basis, providing managers with better information to plan for potential changes.

  20. Food resource partitioning in a fish community of the central Amazon floodplain

    Directory of Open Access Journals (Sweden)

    Bernard de Mérona

    2004-06-01

    Full Text Available Diets of most of fish species inhabiting a floodplain lake in central Amazonia were studied over a two years and half period. Based on the percentage of relative occurrence of 11 major food categories a classification of species in 11 feeding guilds is proposed. Many species were found to be specialized feeders. Fish, detritus and insects were the most important food resources supporting the fish community in both seasons, but the proportions of fruits, invertebrates and fish were reduced during the low water season. At the community level mean diet overlap between species was low, suggesting efficient resource partitioning within the community. However mean overlap between unspecialized feeders was high. Based on the 23 most abundant species belonging to the different feeding guilds, there was no difference in mean overlap between seasons. Whereas individual species exhibited diet changes between high water and low water seasons, there was no general pattern of seasonal change within feeding guilds.Os regimes alimentares da maioria das espécies de peixes de um lago de várzea da Amazônia central foram estudados durante dois anos e meio. Baseada nas percentagens de ocorrência relativa de 11 maiores categorias alimentares, uma classificação das espécies em 11 guildas alimentares é proposta. Muitas espécies foram consideradas especializadas em relação aos seus comportamentos alimentares. Peixes, detritos e insetos foram os recursos alimentares mais importantes ao longo do ano, mas as proporções relativas de frutos, invertebrados e peixes foram reduzidas durante a época de águas baixas. A nível de comunidade a sobreposição média entre espécies foi baixa, sugerindo uma partição eficiente dos recursos alimentares. Entretanto, para espécies não especializadas, os valores de sobreposição foram elevados. Baseado em 23 espécies abundantes, pertencentes a diferentes guildas alimentares, não foi observada diferença na sobreposi

  1. Historical factors that have shaped the evolution of tropical reef fishes: A review of phylogenies, biogeography, and remaining questions.

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    Peter Francis Cowman

    2014-11-01

    Full Text Available Biodiversity patterns across the marine tropics have intrigued evolutionary biologists and ecologists alike. Tropical coral reefs host 1/3 of all marine species of fish on 0.1% of the ocean’s surface. Yet our understanding of how mechanistic processes have underpinned the generation of diversity is limited. However, it has become clear that the biogeographic history of the marine tropics has played an important role in shaping the diversity of tropical reef fishes we see today. In the last decade, molecular phylogenies and age estimation techniques have provided a temporal framework in which the ancestral biogeographic origins of reef fish lineages have been inferred, but few have included fully sampled phylogenies or made inferences at a global scale. We are currently at a point where new sequencing technologies are accelerating the reconstruction and the resolution of the Fish Tree of Life. How will a complete phylogeny of fishes benefit the study of biodiversity in the tropics? Here, I review the literature concerning the evolutionary history of reef-associated fishes from a biogeographic perspective. I summarize the major biogeographic and climatic events over the last 65 million years that have regionalized the tropical marine belt and what effect they have had on the molecular record of fishes and global biodiversity patterns. By examining recent phylogenetic trees of major reef associated groups, I identify gaps to be filled in order to obtain a clearer picture of the origins of coral reef fish assemblages. Finally, I discuss questions that remain to be answered and new approaches to uncover the mechanistic processes that underpin the evolution of biodiversity on coral reefs.

  2. Historical factors that have shaped the evolution of tropical reef fishes: a review of phylogenies, biogeography, and remaining questions.

    Science.gov (United States)

    Cowman, Peter F

    2014-01-01

    Biodiversity patterns across the marine tropics have intrigued evolutionary biologists and ecologists alike. Tropical coral reefs host 1/3 of all marine species of fish on 0.1% of the ocean's surface. Yet our understanding of how mechanistic processes have underpinned the generation of this diversity is limited. However, it has become clear that the biogeographic history of the marine tropics has played an important role in shaping the diversity of tropical reef fishes we see today. In the last decade, molecular phylogenies and age estimation techniques have provided a temporal framework in which the ancestral biogeographic origins of reef fish lineages have been inferred, but few have included fully sampled phylogenies or made inferences at a global scale. We are currently at a point where new sequencing technologies are accelerating the reconstruction and the resolution of the Fish Tree of Life. How will a complete phylogeny of fishes benefit the study of biodiversity in the tropics? Here, I review the literature concerning the evolutionary history of reef-associated fishes from a biogeographic perspective. I summarize the major biogeographic and climatic events over the last 65 million years that have regionalized the tropical marine belt and what effect they have had on the molecular record of fishes and global biodiversity patterns. By examining recent phylogenetic trees of major reef associated groups, I identify gaps to be filled in order to obtain a clearer picture of the origins of coral reef fish assemblages. Finally, I discuss questions that remain to be answered and new approaches to uncover the mechanistic processes that underpin the evolution of biodiversity on coral reefs.

  3. Designing long-term fish community assessments in connecting channels: Lessons from the Saint Marys River

    Science.gov (United States)

    Schaeffer, Jeff; Rogers, Mark W.; Fielder, David G.; Godby, Neal; Bowen, Anjanette K.; O'Connor, Lisa; Parrish, Josh; Greenwood, Susan; Chong, Stephen; Wright, Greg

    2014-01-01

    Long-term surveys are useful in understanding trends in connecting channel fish communities; a gill net assessment in the Saint Marys River performed periodically since 1975 is the most comprehensive connecting channels sampling program within the Laurentian Great Lakes. We assessed efficiency of that survey, with intent to inform development of assessments at other connecting channels. We evaluated trends in community composition, effort versus estimates of species richness, ability to detect abundance changes for four species, and effects of subsampling yellow perch catches on size and age-structure metrics. Efficiency analysis revealed low power to detect changes in species abundance, whereas reduced effort could be considered to index species richness. Subsampling simulations indicated that subsampling would have allowed reliable estimates of yellow perch (Perca flavescens) population structure, while greatly reducing the number of fish that were assigned ages. Analyses of statistical power and efficiency of current sampling protocols are useful for managers collecting and using these types of data as well as for the development of new monitoring programs. Our approach provides insight into whether survey goals and objectives were being attained and can help evaluate ability of surveys to answer novel questions that arise as management strategies are refined.

  4. Socio-demographic factors and fish eating trends in eastern community, Sri Lanka

    OpenAIRE

    Chandravathany Devadawson; Chamilla Jayasinghe; Ramaiah Sivakanesan

    2015-01-01

    Fish are considered as a unique source of protein and long chain polyunsaturated fatty acids (PUFA). In Sri Lankan population, fish consumption habits and attitudes are determined by the availability of fish and socio-demography of fish consumers. An extensive survey was carried out among fish consumers (N=1777) in stratified random manner. Among the total studied respondents, 73.3% of the respondents had eaten all type of fish while10% had only sea fishes, 19.5 % brackish water a...

  5. HIV and AIDS vulnerability in fishing communities in Mangochi district, Malawi.

    Science.gov (United States)

    Nagoli, Joseph; Holvoet, Katrien; Remme, Michelle

    2010-04-01

    The fisheries sector contributes significantly to Malawi's national economy and to the livelihoods of the poor as certain activities in the sector have relatively low barriers to entry. Various studies have shown that the fisheries sector suffers from high HIV prevalence in many low-income countries. In Malawi, HIV prevalence as well as the causes and impact of HIV infections among fisherfolk are yet to be assessed. Participatory action research was conducted in Mangochi District, in the southern part of Lake Malawi, between December 2007 and January 2008, to identify critical HIV-risk points along the value-chain for the Lake Sardine or usipa (Engraulicypris sardella) fishery. Data were collected through interviews with key informants and from focus group discussions at the community, institution, district and market levels. An analysis of vulnerability resulted in the formulation of mechanisms to redress HIV and AIDS prevention and mitigation at each point of vulnerability. The findings show that HIV and AIDS vulnerability in the fishery's market-chain is highest where fish processing and trading influence sexual relationships between fishermen and female fish traders. The period of high usipa catches (December to March) coincides with a period of food shortage and fishing offers income-generating opportunities for many food-insecure households. This increases competition in processing and trading fish, a socio-economic situation that may result in increased instances of transactional sex. The interactions along the usipa fishery's market-chain, from rural to urban settings, also favour the transmission of HIV from areas of high prevalence to areas with otherwise low HIV risk.

  6. Fish communities of the Wilderness Lakes System in the southern Cape, South Africa

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    Alexis A. Olds

    2016-03-01

    Full Text Available The Wilderness Lakes System, a temporarily open and closed estuary with three associated lakes situated in the southern Cape region of South Africa, was sampled using a range of sampling gears to assess the fish community. A total of 25 species were sampled throughout the system, with the highest diversity in the Touw Estuary (23 species and the lowest in Langvlei (11 species. Estuary-associated marine species (13 species dominated species richness with smaller proportions of estuarine resident (7 species, freshwater (3 species and catadromous species (2 species. Estuarine resident species dominated the catch numerically. The size–class distribution of euryhaline marine species indicated that upon entering the Touw Estuary as juveniles, the fish move up the system towards Rondevlei where they appear to remain. Three freshwater species were recorded in the system, all of which are alien to the Wilderness Lakes System. Decreasing salinity in the upper lakes appears to be a driving factor in the distribution and increasing abundance of the freshwater fishes. Sampling followed a drought, with the system experiencing substantially increased levels of mouth closure compared to a similar study conducted in the 1980s. The timing of mouth opening and the degree of connectivity between the lakes influence the nursery function of the system as a whole. Management actions need to focus on improving ecological functioning of this system, in particular how mouth opening is managed, to facilitate nursery function and limit the establishment of invasive species.Conservation implications: Key management actions are required to improve fish recruitment potential into and within the system. These include maintenance of adequate marine inflow through adherence to artificial mouth breaching protocols and improving connectivity between the lakes through sediment removal from localised deposition points within the connecting channels.

  7. Long-term fish community response to a reach-scale stream restoration

    Directory of Open Access Journals (Sweden)

    Patrick D. Shirey

    2016-09-01

    Full Text Available At a global scale, aquatic ecosystems are being altered by human activities at a greater rate than at any other time in history. In recent years, grassroots efforts have generated interest in the restoration of degraded or destroyed aquatic habitats, especially small wetlands and streams where such projects are feasible with local resources. We present ecological management lessons learned from 17 years of monitoring the fish community response to the channel relocation and reach-level restoration of Juday Creek, a 3rd-order tributary of the St. Joseph River in Indiana, USA. The project was designed to increase habitat complexity, reverse the effects of accumulated fine sediment (< 2 mm diameter, and mitigate for the impacts of a new golf course development. The 1997 restoration consisted of new channel construction within two reaches of a 1.2-km section of Juday Creek that also contained two control reaches. A primary social goal of the golf course development and stream restoration was to avoid harm to the non-native brown trout fishery, as symbolic of community concerns for the watershed. Our long-term monitoring effort revealed that, although fine sediment increased over time in the restored reaches, habitat conditions have promoted the resurgence of native fish species. Since restoration, the fish assemblage has shifted from non-native Salmonidae (brown trout, rainbow trout to native Centrarchidae (rock bass, largemouth bass, smallmouth bass. In addition, native, nongame species have remained stable or have increased in population abundance (e.g., Johnny darter, mottled sculpin. The results of this study demonstrate the value of learning from a restoration project to adjust management decisions that enhance environmental quality.

  8. Multiple watershed alterations influence fish community structure in Great Plains prairie streams

    Energy Technology Data Exchange (ETDEWEB)

    Perkin, Joshuah S. [Kansas State Univ., Manhattan, KS (United States). Division of Biology; Troia, Matthew J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kansas State Univ., Manhattan, KS (United States). Division of Biology; Shaw, Dustin C. R. [Kansas State Univ., Manhattan, KS (United States). Division of Biology; Gerken, Joseph E. [Kansas State Univ., Manhattan, KS (United States). Division of Biology. Kansas Cooperative Fish and Wildlife Research Unit; Gido, Keith B. [Kansas State Univ., Manhattan, KS (United States). Division of Biology

    2014-10-26

    Stream fish distributions are commonly linked to environmental disturbances affecting terrestrial landscapes. In Great Plains prairie streams, the independent and interactive effects of watershed impoundments and land cover changes remain poorly understood despite their prevalence and assumed contribution to declining stream fish diversity. We used structural equation models and fish community samples from third-order streams in the Kansas River and Arkansas River basins of Kansas, USA to test the simultaneous effects of geographic location, terrestrial landscape alteration, watershed impoundments and local habitat on species richness for stream-associated and impoundment-associated habitat guilds. Watershed impoundment density increased from west to east in both basins, while per cent altered terrestrial landscape (urbanisation + row-crop agriculture) averaged ~50% in the west, declined throughout the Flint Hills ecoregion and increased (Kansas River basin ~80%) or decreased (Arkansas River basin ~30%) to the east. Geographic location had the strongest effect on richness for both guilds across basins, supporting known zoogeography patterns. In addition to location, impoundment species richness was positively correlated with local habitat in both basins; whereas stream-species richness was negatively correlated with landscape alterations (Kansas River basin) or landscape alterations and watershed impoundments (Arkansas River basin). These findings suggest that convergences in the relative proportions of impoundment and stream species (i.e., community structure) in the eastern extent of both basins are related to positive effects of increased habitat opportunities for impoundment species and negative effects caused by landscape alterations (Kansas River basin) or landscape alterations plus watershed impoundments (Arkansas River basin) for stream species.

  9. Neofunctionalization of a duplicate hatching enzyme gene during the evolution of teleost fishes.

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    Sano, Kaori; Kawaguchi, Mari; Watanabe, Satoshi; Yasumasu, Shigeki

    2014-10-19

    Duplication and subsequent neofunctionalization of the teleostean hatching enzyme gene occurred in the common ancestor of Euteleostei and Otocephala, producing two genes belonging to different phylogenetic clades (clade I and II). In euteleosts, the clade I enzyme inherited the activity of the ancestral enzyme of swelling the egg envelope by cleavage of the N-terminal region of egg envelope proteins. The clade II enzyme gained two specific cleavage sites, N-ZPd and mid-ZPd but lost the ancestral activity. Thus, euteleostean clade II enzymes assumed a new function; solubilization of the egg envelope by the cooperative action with clade I enzyme. However, in Otocephala, the clade II gene was lost during evolution. Consequently, in a late group of Otocephala, only the clade I enzyme is present to swell the egg envelope. We evaluated the egg envelope digestion properties of clade I and II enzymes in Gonorynchiformes, an early diverging group of Otocephala, using milkfish, and compared their digestion with those of other fishes. Finally, we propose a hypothesis of the neofunctionalization process. The milkfish clade II enzyme cleaved N-ZPd but not mid-ZPd, and did not cause solubilization of the egg envelope. We conclude that neofunctionalization is incomplete in the otocephalan clade II enzymes. Comparison of clade I and clade II enzyme characteristics implies that the specificity of the clade II enzymes gradually changed during evolution after the duplication event, and that a change in substrate was required for the addition of the mid-ZPd site and loss of activity at the N-terminal region. We infer the process of neofunctionalization of the clade II enzyme after duplication of the gene. The ancestral clade II gene gained N-ZPd cleavage activity in the common ancestral lineage of the Euteleostei and Otocephala. Subsequently, acquisition of cleavage activity at the mid-ZPd site and loss of cleavage activity in the N-terminal region occurred during the evolution of

  10. Tracking adaptive evolution in the structure, function and molecular phylogeny of haemoglobin in non-Antarctic notothenioid fish species

    Science.gov (United States)

    Verde, Cinzia; Parisi, Elio; di Prisco, Guido

    2006-04-01

    With the notable exception of Antarctic icefishes, haemoglobin (Hb) is present in all vertebrates. In polar fish, Hb evolution has included adaptations with implications at the biochemical, physiological and molecular levels. Cold adaptation has been shown to be also linked to small changes in primary structure and post-translational modifications in proteins, including hydrophobic remodelling and increased flexibility. A wealth of knowledge is available on the oxygen-transport system of fish inhabiting Antarctic waters, but very little is known on the structure and function of Hb of non-Antarctic notothenioid fishes. The comparison of the biochemical and physiological adaptations between cold-adapted and non-cold-adapted species is a powerful tool to understand whether (and to what extent) extreme environments require specific adaptations or simply select for phenotypically different life styles. This study focuses on structure, function and molecular phylogeny of Hb in Antarctic and non-Antarctic notothenioid fishes. The rationale is to use the primary structure of Hb as tool of choice to gain insight into the pathways of the evolution history of α and β globins of notothenioids and also as a basis for reconstructing the phylogenetic relationships among Antarctic and non-Antarctic species.

  11. Composition of Fish Communities in a European Macrotidal Salt Marsh (the Mont Saint-Michel Bay, France)

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    Laffaille, P.; Feunteun, E.; Lefeuvre, J.-C.

    2000-10-01

    At least 100 fish species are known to be present in the intertidal areas (estuaries, mudflats and salt marshes) of Mont Saint-Michel Bay. These and other comparable shallow marine coastal waters, such as estuaries and lagoons, play a nursery role for many fish species. However, in Europe little attention has been paid to the value of tidal salt marshes for fishes. Between March 1996 and April 1999, 120 tides were sampled in a tidal creek. A total of 31 species were caught. This community was largely dominated by mullets ( Liza ramada represent 87% of the total biomass) and sand gobies ( Pomatoschistus minutus and P. lozanoi represent 82% of the total numbers). These species and also Gasterosteus aculeatus , Syngnathus rostellatus, Dicentrarchus labrax, Mugil spp., Liza aurata and Sprattus sprattus were the most frequent species (>50% of monthly frequency of occurrence). In Europe, salt marshes and their creeks are flooded only during high spring tides. So, fishes only invade this environment during short immersion periods, and no species can be considered as marsh resident. But, the salt marsh was colonized by fish every time the tide reached the creek, and during the short time of flood, dominant fishes fed actively and exploited the high productivity. Nevertheless, this study shows that there is little interannual variation in the fish community and there are three ' seasons ' in the fish fauna of the marsh. Marine straggler and marine estuarine dependent species colonize marshes between spring (recruitment period in the bay) and autumn before returning into deeper adjacent waters. Estuarine fishes are present all year round with maximum abundances in the end of summer. The presence of fishes confirms that this kind of wetland plays an important trophic and nursery role for these species. Differences in densities and stages distribution of these species into Mont Saint-Michel systems (tidal mudflats, estuaries and tidal salt marshes) can reduce the trophic

  12. Environmental Determinants Influencing Fish Community Structure and Diversity in Two Distinct Seasons among Wetlands of Northern Region (Ghana

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    Collins Ayine Nsor

    2016-01-01

    Full Text Available Fish community structure was assessed in six wetlands using cast nets, to correlate with environmental variables with diversity and distribution patterns, from 2010 to 2012. A total of 2,239 individuals belonging to 44 species and 1,938 individuals belonging to 40 species were sampled in the dry and wet seasons. Mochokid and Mormyrid families dominated fish community and constituted 14.8%, respectively, followed by Alestids (12.9% and Chlariids (11.1%. Rarer taxons were centropomids, channids, malapteruds, and oesteoglossids and represented 1.9%, respectively. Overall, CPUE per net did not vary significantly (Tukey HSD test, p=0.27 in the dry and wet seasons. Wuntori marsh consistently showed dominance in mean monthly CPUE per net (dry = 115±4.5; wet = 107±7.7 seasons, while Bunglung constructed wetland was the least recorded (dry = 56.5±6.2; wet = 58.3±4.1 seasons. Fish diversity and richness differed significantly (F=0.11, p=0.03 among seasons. Environmental disturbances were season-specific and did not differ significantly (F=0.16, df=14, p=0.97 among sites. A DCA ordination explained 69% variability in fish distribution patterns, while PCA showed that 81.8% of nitrate-nitrogen, phosphate, and grazing intensity on axis 1 and conductivity, temperature, and turbidity on axis 2 influenced fish community structure. Wetland conservation must be promoted to sustain fish abundance and overall ecosystem stability.

  13. Recovery of fish communities in the Finniss River, northern Australia, following remediation of the Rum Jungle uranium/copper mine site.

    Science.gov (United States)

    Jeffree, R A; Twining, J R; Thomson, J

    2001-07-15

    The Finniss River in the wet-dry tropics of northern Australia has received acid rock drainage (ARD) contaminants from the Rum Jungle uranium/copper mine site over more than four decades. Annual-cycle loads of Cu, Zn, Mn, and sulfate, calculated from daily water and flow measurements, have been determined both prior to and following mine-site remediation, that began in the early 1980s. The effects of varying contaminant loads on the relative abundances of seven fish species, sampled by enmeshing nets during dry seasons, were determined by nonmetric multidimensional scaling (nMDS), in combination with cluster-analysis and other nonparametric statistical techniques. These analyses showed that (i) prior to remediation, the impacted region of the Finniss River in 1974 had significantly dissimilar (P < 0.001) and more heterogeneous fish communities, generally characterized by reduced diversity and abundance, compared to sites unexposed to elevated contaminant water concentrations and (ii) postremediation, recovery in fish communities from the impacted region was indicated because they were not significantly dissimilar from those sampled at contemporary (P = 0.16) unimpacted sites, that were also similar to preremedial unimpacted sites. Even though considerable contaminant loads are still being delivered to the impacted region of the Finniss River over the annual cycle, the recovery in fish diversity and abundances is consistent with (a) reductions of in situ contaminant water concentrations at the time of fish sampling, (b) reductions in annual-cycle contaminant loads of sulfate, Cu, Zn, and Mn by factors of 3-7, (c) greatly reduced frequencies of occurrence and magnitude of elevated contaminant water concentrations over the annual cycle, that was most pronounced for Cu, and (d) the absence of extensive fish-kills during the first-flushes of contaminants into the Finniss river proper at the beginning of the wet season, that were observed prior to remediation. As such

  14. Fish-mediated changes in bacterioplankton community composition: an in situ mesocosm experiment

    Science.gov (United States)

    Luo, Congqiang; Yi, Chunlong; Ni, Leyi; Guo, Longgen

    2017-06-01

    We characterized variations in bacterioplankton community composition (BCC) in mesocosms subject to three different treatments. Two groups contained fish (group one: Cyprinus carpio; group two: Hypophthalmichthys molitrix); and group three, the untreated mesocosm, was the control. Samples were taken seven times over a 49-day period, and BCC was analyzed by PCR-denaturing gradient gel electrophoresis (DGGE) and real-time quantitative PCR (qPCR). Results revealed that introduction of C. carpio and H. molitrix had a remarkable impact on the composition of bacterioplankton communities, and the BCC was significantly different between each treatment. Sequencing of DGGE bands revealed that the bacterioplankton community in the different treatment groups was consistent at a taxonomic level, but differed in its abundance. H. molitrix promoted the richness of Alphaproteobacteria and Actinobacteria, while more bands affiliated to Cyanobacteria were detected inC. carpio mesocosms. The redundancy analysis (RDA) result demonstrated that the BCC was closely related to the bottom-up (total phosphorus, chlorophyll a, phytoplankton biomass) and top-down forces (biomass of copepods and cladocera) in C. carpio and control mesocosms, respectively. We found no evidence for top-down regulation of BCC by zooplankton in H. molitrix mesocosms, while grazing by protozoa (heterotrophic nanoflagellates, ciliates) became the major way to regulate BCC. Total bacterioplankton abundances were significantly higher in C. carpio mesocosms because of high nutrient concentration and suspended solids. Our study provided insights into the relationship between fish and bacterioplankton at species level, leading to a deep understanding of the function of the microbial loop and the aquatic ecosystem.

  15. Host specificity and the structure of helminth parasite communities of fishes in a Neotropical river in Mexico

    Science.gov (United States)

    Salgado-Maldonado, Guillermo; Novelo-Turcotte, María Teresa; Caspeta-Mandujano, Juan Manuel; Vazquez-Hurtado, Gabriela; Quiroz-Martínez, Benjamin; Mercado-Silva, Norman; Favila, Mario

    2016-01-01

    In a tropical locality of Río La Antigua, Veracruz, Mexico, 11 fish species, represented by 244 individual fish from six freshwater fish families living sympatrically and synchronically, were examined for helminth parasites. A total of 36 taxa of helminths were recorded, 24 autogenic and 12 allogenic forms, including 6 monogeneans, 14 trematodes, 1 cestode, and 15 nematodes. Most helminth taxa were recovered for 10/11 of the component communities we analyzed. The results contribute empirical evidence that host specificity is an important force in the development of helminth communities of freshwater fishes. Each fish family has their own set of parasites, host species belonging to the same taxon share parasite species. High component community similarity among related host species was recorded, demonstrated by high prevalence and abundance, as well as dominance, of autogenic specialist species in each component community. Most autogenic helminth species are numerically and reproductively successful in relatively few host species. Autogenic helminths common in one host species are not common in others. Our findings give empirical support to the idea that low levels of sharing of parasites favor animal coexistence and high species richness, because large phylogenetic differences allow potentially competing animals to consume the same resources without being sensitive of another’s parasites. PMID:28004635

  16. Host specificity and the structure of helminth parasite communities of fishes in a Neotropical river in Mexico

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    Salgado-Maldonado Guillermo

    2016-01-01

    Full Text Available In a tropical locality of Río La Antigua, Veracruz, Mexico, 11 fish species, represented by 244 individual fish from six freshwater fish families living sympatrically and synchronically, were examined for helminth parasites. A total of 36 taxa of helminths were recorded, 24 autogenic and 12 allogenic forms, including 6 monogeneans, 14 trematodes, 1 cestode, and 15 nematodes. Most helminth taxa were recovered for 10/11 of the component communities we analyzed. The results contribute empirical evidence that host specificity is an important force in the development of helminth communities of freshwater fishes. Each fish family has their own set of parasites, host species belonging to the same taxon share parasite species. High component community similarity among related host species was recorded, demonstrated by high prevalence and abundance, as well as dominance, of autogenic specialist species in each component community. Most autogenic helminth species are numerically and reproductively successful in relatively few host species. Autogenic helminths common in one host species are not common in others. Our findings give empirical support to the idea that low levels of sharing of parasites favor animal coexistence and high species richness, because large phylogenetic differences allow potentially competing animals to consume the same resources without being sensitive of another’s parasites.

  17. Fish community monitoring in Lisbon Bottom and Jameson Island, restoration units of the Big Muddy National Fish and Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Numerous braided channels, islands, backwaters, sloughs, wetlands, and sandbars historically characterized the Missouri River. Human modifications such as the...

  18. Sustainability of the Lake Superior fish community: Interactions in a food web context

    Science.gov (United States)

    Kitchell, James F.; Cox, Sean P.; Harvey, Chris J.; Johnson, Timothy B.; Mason, Doran M.; Schoen, Kurt K.; Aydin, Kerim; Bronte, Charles; Ebener, Mark; Hansen, Michael; Hoff, Michael; Schram, Steve; Schreiner, Don; Walters, Carl J.

    2000-01-01

    The restoration and rehabilitation of the native fish communities is a long-term goal for the Laurentian Great Lakes. In Lake Superior, the ongoing restoration of the native lake trout populations is now regarded as one of the major success stories in fisheries management. However, populations of the deepwater morphotype (siscowet lake trout) have increased much more substantially than those of the nearshore morphotype (lean lake trout), and the ecosystem now contains an assemblage of exotic species such as sea lamprey, rainbow smelt, and Pacific salmon (chinook, coho, and steelhead). Those species play an important role in defining the constraints and opportunities for ecosystem management. We combined an equilibrium mass balance model (Ecopath) with a dynamic food web model (Ecosim) to evaluate the ecological consequences of future alternative management strategies and the interaction of two different sets of life history characteristics for fishes at the top of the food web. Relatively rapid turnover rates occur among the exotic forage fish, rainbow smelt, and its primary predators, exotic Pacific salmonids. Slower turnover rates occur among the native lake trout and burbot and their primary prey—lake herring, smelt, deepwater cisco, and sculpins. The abundance of forage fish is a key constraint for all salmonids in Lake Superior. Smelt and Mysis play a prominent role in sustaining the current trophic structure. Competition between the native lake trout and the exotic salmonids is asymmetric. Reductions in the salmon population yield only a modest benefit for the stocks of lake trout, whereas increased fishing of lake trout produces substantial potential increases in the yields of Pacific salmon to recreational fisheries. The deepwater or siscowet morphotype of lake trout has become very abundant. Although it plays a major role in the structure of the food web it offers little potential for the restoration of a valuable commercial or recreational fishery

  19. Evolution of Wenger's concept of community of practice

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    Coyte Peter C

    2009-03-01

    Full Text Available Abstract Background In the experience of health professionals, it appears that interacting with peers in the workplace fosters learning and information sharing. Informal groups and networks present good opportunities for information exchange. Communities of practice (CoPs, which have been described by Wenger and others as a type of informal learning organization, have received increasing attention in the health care sector; however, the lack of uniform operating definitions of CoPs has resulted in considerable variation in the structure and function of these groups, making it difficult to evaluate their effectiveness. Objective To critique the evolution of the CoP concept as based on the germinal work by Wenger and colleagues published between 1991 and 2002. Discussion CoP was originally developed to provide a template for examining the learning that happens among practitioners in a social environment, but over the years there have been important divergences in the focus of the concept. Lave and Wenger's earliest publication (1991 centred on the interactions between novices and experts, and the process by which newcomers create a professional identity. In the 1998 book, the focus had shifted to personal growth and the trajectory of individuals' participation within a group (i.e., peripheral versus core participation. The focus then changed again in 2002 when CoP was applied as a managerial tool for improving an organization's competitiveness. Summary The different interpretations of CoP make it challenging to apply the concept or to take full advantage of the benefits that CoP groups may offer. The tension between satisfying individuals' needs for personal growth and empowerment versus an organization's bottom line is perhaps the most contentious of the issues that make CoPs difficult to cultivate. Since CoP is still an evolving concept, we recommend focusing on optimizing specific characteristics of the concept, such as support for members

  20. Coding early naturalists' accounts into long-term fish community changes in the Adriatic Sea (1800-2000.

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    Tomaso Fortibuoni

    Full Text Available The understanding of fish communities' changes over the past centuries has important implications for conservation policy and marine resource management. However, reconstructing these changes is difficult because information on marine communities before the second half of the 20(th century is, in most cases, anecdotal and merely qualitative. Therefore, historical qualitative records and modern quantitative data are not directly comparable, and their integration for long-term analyses is not straightforward. We developed a methodology that allows the coding of qualitative information provided by early naturalists into semi-quantitative information through an intercalibration with landing proportions. This approach allowed us to reconstruct and quantitatively analyze a 200-year-long time series of fish community structure indicators in the Northern Adriatic Sea (Mediterranean Sea. Our analysis provides evidence of long-term changes in fish community structure, including the decline of Chondrichthyes, large-sized and late-maturing species. This work highlights the importance of broadening the time-frame through which we look at marine ecosystem changes and provides a methodology to exploit, in a quantitative framework, historical qualitative sources. To the purpose, naturalists' eyewitness accounts proved to be useful for extending the analysis on fish community back in the past, well before the onset of field-based monitoring programs.

  1. The Capacity to Detect Change Stream Fish Communities Characteristics at the Site-Level in the Lake Ontario Basin

    Science.gov (United States)

    Jones, Nicholas Edward; Petreman, Ian Charles

    2012-07-01

    We investigate natural inter-annual variability of fish community measures within streams of the Lake Ontario basin. Given this variability, we examined coefficients of variation (CV) among the community measures and three scenarios pertaining to the capacity of biologists to detect changes in the fish community at the stream site level. Results indicate that Ontario's stream fish communities are highly variable in time. Young-of-the-year rainbow trout growth was the least variable whereas biomass density scored the highest CV of 0.50 among streams (range 0.22-0.99). Given the CVs and relatively equal sample sizes, our measures of the fish community can be ranked from least to most powerful: biomass, density, richness, diversity, and growth of young-of-the-year rainbow trout. Only large changes in measures can typically be detected. For instance, it would take 4-6 years of monitoring before and after a pulse perturbation to detect a 50 % change in species richness or diversity. We suggest that monitoring abundance is unlikely to result in the detection of small impacts within a short period of time and that large effects can be masked by low statistical power. This evidence voices the need for more research into better sampling methods, experimental designs, and choice of indicators to support monitoring programs for flowing waters.

  2. Effects of Dam Removal on Fish Community Interactions and Stability in the Eightmile River System, Connecticut, USA

    Science.gov (United States)

    Poulos, Helen M.; Chernoff, Barry

    2017-02-01

    New multivariate time-series methods have the potential to provide important insights into the effects of ecosystem restoration activities. To this end, we examined the temporal effects of dam removal on fish community interactions using multivariate autoregressive models to understand changes in fish community structure in the Eightmile River System, Connecticut, USA. We sampled fish for 6 years during the growing season; 1 year prior to, 2 years during, and for 3 years after a small dam removal event. The multivariate autoregressive analysis revealed that the site above the dam was the most reactive and least resilient sample site, followed in order by the below-dam and nearby reference site. Even 3 years after the dam removal event, the stream was still in a recovery stage that had failed to approximate the community structure of the reference site. This suggests that the reorganization of fish communities following dam removals, with the goal of ecological restoration, may take decades to centuries for the restored sites to approximate the community structure of nearby undisturbed sites. Results from this study also highlight the utility of multivariate autoregressive modeling for examining temporal interactions among species in response to adaptive management activities both in aquatic systems and elsewhere.

  3. Phylogenetic analyses provide insights into the historical biogeography and evolution of Brachyrhaphis fishes.

    Science.gov (United States)

    Ingley, Spencer J; Reina, Ruth G; Bermingham, Eldredge; Johnson, Jerald B

    2015-08-01

    The livebearing fish genus Brachyrhaphis (Poeciliidae) has become an increasingly important model in evolution and ecology research, yet the phylogeny of this group is not well understood, nor has it been examined thoroughly using modern phylogenetic methods. Here, we present the first comprehensive phylogenetic analysis of Brachyrhaphis by using four molecular markers (3mtDNA, 1nucDNA) to infer relationships among species in this genus. We tested the validity of this genus as a monophyletic group using extensive outgroup sampling based on recent phylogenetic hypotheses of Poeciliidae. We also tested the validity of recently described species of Brachyrhaphis that are part of the B. episcopi complex in Panama. Finally, we examined the impact of historical events on diversification of Brachyrhaphis, and made predictions regarding the role of different ecological environments on evolutionary diversification where known historical events apparently fail to explain speciation. Based on our results, we reject the monophyly of Brachyrhaphis, and question the validity of two recently described species (B. hessfeldi and B. roswithae). Historical biogeography of Brachyrhaphis generally agrees with patterns found in other freshwater taxa in Lower Central America, which show that geological barriers frequently predict speciation. Specifically, we find evidence in support of an 'island' model of Lower Central American formation, which posits that the nascent isthmus was partitioned by several marine connections before linking North and South America. In some cases where historic events (e.g., vicariance) fail to explain allopatric species breaks in Brachyrhaphis, ecological processes (e.g., divergent predation environments) offer additional insight into our understanding of phylogenetic diversification in this group.

  4. Evolution of opercle shape in cichlid fishes from Lake Tanganyika - adaptive trait interactions in extant and extinct species flocks.

    Science.gov (United States)

    Wilson, Laura A B; Colombo, Marco; Sánchez-Villagra, Marcelo R; Salzburger, Walter

    2015-11-20

    Phenotype-environment correlations and the evolution of trait interactions in adaptive radiations have been widely studied to gain insight into the dynamics underpinning rapid species diversification. In this study we explore the phenotype-environment correlation and evolution of operculum shape in cichlid fishes using an outline-based geometric morphometric approach combined with stable isotope indicators of macrohabitat and trophic niche. We then apply our method to a sample of extinct saurichthyid fishes, a highly diverse and near globally distributed group of actinopterygians occurring throughout the Triassic, to assess the utility of extant data to inform our understanding of ecomorphological evolution in extinct species flocks. A series of comparative methods were used to analyze shape data for 54 extant species of cichlids (N = 416), and 6 extinct species of saurichthyids (N = 44). Results provide evidence for a relationship between operculum shape and feeding ecology, a concentration in shape evolution towards present along with evidence for convergence in form, and significant correlation between the major axes of shape change and measures of gut length and body elongation. The operculum is one of few features that can be compared in extant and extinct groups, enabling reconstruction of phenotype-environment interactions and modes of evolutionary diversification in deep time.

  5. The community structure of over-wintering larval and small juvenile fish in a large estuary

    Science.gov (United States)

    Munk, Peter; Cardinale, Massimiliano; Casini, Michele; Rudolphi, Ann-Christin

    2014-02-01

    The Skagerrak and Kattegat are estuarine straits of high hydrographical and ecological diversity, situated between the saline waters of the North Sea and the brackish waters of the Baltic Sea. These sustain important nursery grounds of many fish species, of which several overwinter during the larval and early juvenile stages. In order to give more insight into the communities of the overwintering ichthyoplankton in estuarine areas, we examine an annual series of observations from a standard survey carried out 1992-2010. Species differences and annual variability in distributions and abundances are described, and linkages between ichthyoplankton abundances and corresponding hydrographical information are analysed by GAM methods. Communities were dominated by herring, gobies, butterfish, sprat, pipefishes, lemon sole and European eel (i.e. glass eel), and all the sampled species showed large annual fluctuations in abundances. The species showed quite specific patterns of distribution although species assemblages with common distributional characteristics were identified. Within these assemblages, the ichthyoplankton abundances showed linkage to environmental characteristics described by bottom-depth and surface temperature and salinity. Hence the study points to a significant structuring of overwintering ichthyoplankton communities in large estuaries, based on the species habitat choice and its response to physical gradients.

  6. Exploring the larval fish community of the central Red Sea with an integrated morphological and molecular approach

    KAUST Repository

    Isari, Stamatina

    2017-08-03

    An important aspect of population dynamics for coral reef fishes is the input of new individuals from the pelagic larval pool. However, the high biodiversity and the difficulty of identifying larvae of closely related species represent obstacles to more fully understanding these populations. In this study, we combined morphology and genetic barcoding (Cytochrome Oxidase I gene) to characterize the seasonal patterns of the larval fish community at two sites in close proximity to coral reefs in the central-north Red Sea: one shallower inshore location (50 m depth) and a nearby site located in deeper and more offshore waters (~ 500 m depth). Fish larvae were collected using oblique tows of a 60 cm-bongo net (500 μm mesh size) every month for one year (2013). During the warmer period of the year (June-November), the larval fish stock was comparable between sampling sites. However, during the colder months, abundances were higher in the inshore than in the offshore waters. Taxonomic composition and temporal variation of community structure differed notably between sites, potentially reflecting habitat differences, reproductive patterns of adults, and/or advective processes in the area. Eleven out of a total of 62 recorded families comprised 69–94% of the fish larval community, depending on sampling site and month. Richness of taxa was notably higher in the inshore station compared to the offshore, particularly during the colder period of the year and especially for the gobiids and apogonids. Two mesopelagic taxa (Vinciguerria sp. and Benthosema spp.) comprised an important component of the larval community at the deeper site with only a small and sporadic occurrence in the shallower inshore waters. Our data provide an important baseline reference for the larval fish communities of the central Red Sea, representing the first such study from Saudi Arabian waters.

  7. Environmental changes on freshwater fish communities in South America in the last five decades: a case study in northeast Argentina.

    Directory of Open Access Journals (Sweden)

    Alejandra Volpedo

    2017-01-01

    Full Text Available Environmental changes together with other stressors, such as habitat destruction, may cause widespread extinctions, decrease in biodiversity and disrupt natural communities, resulting in novel species assemblages. South America has a large diversity of freshwater fishes with complex evolutionary histories, mainly due to the presence of a wide variety of aquatic environments. Argentina has experienced an increase in rainfall in the last five decades leading to important climatic and hydrological changes. These changes caused the displacement of the isohyets towards the west. This study reports changes in the composition of freshwater fishes in northeast Argentina during the last five decades, and investigated a causal relationship between the variation in fish assemblages and climate change. The changes in the distribution and composition of fish communities between 1962 and 2010 were analyzed in 22 stations. These stations were agrouped in relation to the ichthyogeographic provinces: Great Rivers province (GRp and Pampean province (Pp. The correlation between rainfall in relation to the number total species from each of the studied provinces showed a significant positive correlation in Pp and not correlation in GRp. The annual mean river discharge and the number of total species from each ecoregion showed a significant positive correlation in GRp, and not correlation in Pp. The results of this study strongly suggest that the rainfall variations and river discharges observed in northeast Argentina induced changes in the composition of fish assemblages that lead to the redistribution of fish species among ichthyogeographic provinces.

  8. Evolution in the block: common elements of 5S rDNA organization and evolutionary patterns in distant fish genera.

    Science.gov (United States)

    Campo, Daniel; García-Vázquez, Eva

    2012-01-01

    The 5S rDNA is organized in the genome as tandemly repeated copies of a structural unit composed of a coding sequence plus a nontranscribed spacer (NTS). The coding region is highly conserved in the evolution, whereas the NTS vary in both length and sequence. It has been proposed that 5S rRNA genes are members of a gene family that have arisen through concerted evolution. In this study, we describe the molecular organization and evolution of the 5S rDNA in the genera Lepidorhombus and Scophthalmus (Scophthalmidae) and compared it with already known 5S rDNA of the very different genera Merluccius (Merluccidae) and Salmo (Salmoninae), to identify common structural elements or patterns for understanding 5S rDNA evolution in fish. High intra- and interspecific diversity within the 5S rDNA family in all the genera can be explained by a combination of duplications, deletions, and transposition events. Sequence blocks with high similarity in all the 5S rDNA members across species were identified for the four studied genera, with evidences of intense gene conversion within noncoding regions. We propose a model to explain the evolution of the 5S rDNA, in which the evolutionary units are blocks of nucleotides rather than the entire sequences or single nucleotides. This model implies a "two-speed" evolution: slow within blocks (homogenized by recombination) and fast within the gene family (diversified by duplications and deletions).

  9. Diversity of the bacterial community in Myanmar traditional salted fish yegyo ngapi.

    Science.gov (United States)

    Kobayashi, Takeshi; Taguchi, Chihiro; Kida, Kakeru; Matsuda, Hiroko; Terahara, Takeshi; Imada, Chiaki; Moe, Nant Kay Thwe; Thwe, Su Myo

    2016-10-01

    The distribution and characterization of bacteria including lactic acid bacteria (LAB) in the traditional and popular salted fish yegyo ngapi in Myanmar were studied to clarify the contribution of these bacteria to the curing and ripening of this product. Samples of yegyo ngapi purchased from a market in Yangon were used. Most of the isolates obtained using de Man, Rogosa and Sharpe medium containing 10 % NaCl were identified as coccoid LAB on the basis of their basic phenotypic characteristics. From the results of 16S rRNA gene sequencing and PCR-restriction fragment length polymorphism analysis of this gene, most of the isolates were identified as the halophilic LAB Tetragenococcus muriaticus. Analyses of the 16S rRNA gene based on the clone library using DNA extracted from salted fish products were also performed. The results of these molecular-analysis-based techniques showed that spore-forming and non-spore-forming anaerobic bacteria including the genera Clostridium and Halanaerobium in addition to T. muriaticus were also frequently found in bacterial communities. These findings suggest that the anaerobic condition during curing and ripening resulted in bacterial communities composed of strictly anaerobic bacteria and halophilic LAB, and that these bacteria might also contribute to the manufacturing processes of this product. In addition, DNA sequences similar to that of Clostridium botulinum were found in the clone library analysis. Therefore, despite no reports of botulism poisoning from the region where the samples were taken, closer surveillance should be carried out from the viewpoint of food safety.

  10. The influence of fire-coral colony size and agonistic behaviour of territorial damselfish on associated coral reef fish communities.

    Science.gov (United States)

    Leal, Isabela Carolina Silva; de Araújo, Maria Elisabeth; da Cunha, Simone Rabelo; Pereira, Pedro Henrique Cipresso

    2015-07-01

    Branching hydrocorals from the genus Millepora play an important ecological role in South Atlantic reefs, where branching scleractinian corals are absent. Previous studies have shown a high proportion of reef fish species using branching fire-coral colonies as shelter, breeding, and feeding sites. However, the effects of Millepora spp. colony size and how the agonistic behaviour of a competitive damselfish affect the associated reef fish community are still unknown. The present study examined how fire-coral colony volume and the presence of a highly territorial and aggressive damselfish (Brazilian endemic Stegastes fuscus) affects the reef fish community associated with the fire-coral Millepora alcicornis. M. alcicornis colonies were surveyed from September 2012 to April 2013 at Tamandaré Reefs off Northeast Brazil. Our results show that the abundance and richness of coral associated fish was positively correlated with M. alcicornis coral colony volume. Additionally, behaviour of S. fuscus, the most abundant reef fish species found associated with fire-coral colonies (almost 57% of the fish community), was also influenced by fire-coral colony volume. There was a clear trend of increased agonistic behaviour and feeding on coral polyps as colony volume increased. This trend was reversed for the non-occupational swimming category, which decreased as M. alcicornis colony volume increased. Behavioural ontogenetic changes were also detected for S. fuscus individuals. Juveniles mainly showed two distinct behaviours: sheltered on coral branches and feeding on coral polyps. In contrast, adults presented greater equitability among the behavioural categories, mostly non-occupational swimming around coral colonies and agonistic behaviour. Lastly, S. fuscus individuals actively defended fire-coral colonies from intruders. A large number of agonistic interactions occurred against potential food competitors, which were mainly roving herbivores, omnivores, and sessile

  11. Chromosome evolution in fishes: a new challenging proposal from Neotropical species

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    Mauro Nirchio

    2014-12-01

    Full Text Available We present a database containing cytogenetic data of Neotropical actinopterygian fishes from Venezuela obtained in a single laboratory for the first time. The results of this study include 103 species belonging to 74 genera assigned to 45 families and 17 out of the 40 teleost orders. In the group of marine fishes, the modal diploid number was 2n=48 represented in 60% of the studied species, while in the freshwater fish group the modal diploid complement was 2n=54, represented in 21.21 % of the studied species. The average number of chromosomes and the mean FN were statistically higher in freshwater fish than in marine fish. The degree of diversification and karyotype variation was also higher in freshwater fish in contrast to a more conserved cytogenetic pattern in marine fish. In contrast to the assumption according to which 48 acrocentric chromosomes was basal chromosome number in fish, data here presented show that there is an obvious trend towards the reduction of the diploid number of chromosomes from values near 2n=60 with high number of biarmed chromosomes in more basal species to 2n=48 acrocentric elements in more derived Actinopterygii.

  12. Evolution of the Sensor Fish Device for Measuring Physical Conditions in Severe Hydraulic Environments

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Thomas J.; Duncan, Joanne P.

    2003-02-28

    To assist in deriving biological specifications for design of turbine rehabilitation measures, new ''fish-friendly'' turbines, and spillway designs and operations, scientists at the Pacific Northwest National Laboratory (PNNL) have developed and tested an autonomous multi-sensor device called a Sensor Fish that can acquire pressure and tri-axial linear acceleration data during passage through severe hydraulic conditions. The purpose of the Sensor Fish is to characterize physical conditions fish experience during passage through hydro turbines, spill stilling basins, high-discharge outfalls, and other dam passage routes. The Sensor Fish was developed with the support of the U.S. Department of Energy's Advanced Hydropower Turbine System program. Field tests of the Sensor Fish at Rock Island, McNary, The Dalles, Bonneville, and Wanapum dams on the Columbia River and the Prosser Irrigation District on the Yakima River have shown that the device can withstand the severe environments of turbine, spill, and fish bypass passage and provide useful environmental data that can ultimately aid in the design and operation of new and existing turbines, spill, and dam fish bypass facilities.

  13. Trophic analysis of the fish community in the Ciénega Churince, Cuatro Ciénegas, Coahuila

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    Ariana Hernández

    2017-09-01

    Full Text Available Fish diets were analyzed to evaluate the dynamic trophs of the fish community in the Churince wetland system of the Cuatro Ciénegas, where the fauna consists of nine species: endemic, native and introduced. In nine sampling events (between February 2011 and May 2014 556 specimens of all nine species were collected. Stomach contents were analyzed and the Relative Importance Index (IRI was calculated. The feed coefficient (Q of the diets and the accumulated trophic diversity (Hk, as well as the amplitude of the trophic niche were evaluated. Feeding strategies in the fish community were found to be eurifagic. The main foods in general were insects, crustaceans, gastropods, plants and teleosts. According to the average linkage method, four functional trophic groups were defined, with no higher consumption species; nevertheless all were regulators, mainly invertebrates. Therefore, the chain reaction in food control was higher from top to bottom, meaning a downwards dietary control.

  14. Trophic analysis of the fish community in the Ciénega Churince, Cuatro Ciénegas, Coahuila.

    Science.gov (United States)

    Hernández, Ariana; Espinosa-Pérez, Hector S; Souza, Valeria

    2017-01-01

    Fish diets were analyzed to evaluate the dynamic trophs of the fish community in the Churince wetland system of the Cuatro Ciénegas, where the fauna consists of nine species: endemic, native and introduced. In nine sampling events (between February 2011 and May 2014) 556 specimens of all nine species were collected. Stomach contents were analyzed and the Relative Importance Index (IRI) was calculated. The feed coefficient (Q) of the diets and the accumulated trophic diversity (Hk), as well as the amplitude of the trophic niche were evaluated. Feeding strategies in the fish community were found to be eurifagic. The main foods in general were insects, crustaceans, gastropods, plants and teleosts. According to the average linkage method, four functional trophic groups were defined, with no higher consumption species; nevertheless all were regulators, mainly invertebrates. Therefore, the chain reaction in food control was higher from top to bottom, meaning a downwards dietary control.

  15. Fish community diversity in the middle continental shelf of the East China Sea

    Institute of Scientific and Technical Information of China (English)

    SHAN Xiujuan; JIN Xianshi; ZHOU Zhipeng; DAI Fangqun

    2011-01-01

    The status of fishery stocks in the coastal waters of China is far from ideal,mainly due to climate change and the impacts of human activities (e.g.,pollution and overfishing).Thus,the restoration and protection of fishery resources have become critical and complex.The stability and balanced structure of the fish community is a basic foundation for the protection of fishery resources.Based on data collected from bottom trawls by the R/V Beidou in continental shelf of the East China Sea in November 2006 and February 2007,changes in the composition and diversity of fish species and functional groups were analyzed.The research area was divided into offshore waters and inshore waters by the two-way indicator species analysis (TWIA).The results showed that the dominant species were different between offshore waters and inshore waters and also varied with the survey time.The most abundant family was Sciaenidae and Teraponidae in November 2006,Sciaenidae,Engraulidae and Triglidae were most abundant in February 2007.The species belonged mainly to mobile piscivores (G6),benthivores/piscivores (G4),benthivores (G3) and planktivores (G1),and the dominant species in November 2006 were commercial species (e.g.Larimichthys polyactis and Trichiurus japonicus),but small-sized species were dominant in February 2007 (e.g.,Harpadon nehereus,Benthosema pterotum,Champsodon capensis,and Acropoma japonicum).The species diversity showed a similar trend as the functional group diversity.Stations with higher diversity were mainly distributed in inshore waters in February 2007,whereas higher diversity was found in offshore waters in November 2006.The highest biomass and species number were found in G6 group,followed by the G4,G5 and G1 groups.The distribution of the number of individuals of each functional group showed the opposite trend as that of the biomass distribution.In addition,the size spectra were mainly concentrated around 3-29 cm,and the individual number of fish species gradually

  16. An assessment of fish communities along a piedmont river receiving organic pollution (Aconquija Mountains, Argentina

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    fernandez luis

    2010-08-01

    Full Text Available

    The relationships between fish assemblage structure and environmental variables along a pollution gradient in the Medina River were analyzed over a year in four sampling sites (S1-S4. The river flows in a mountain-plain transition and is affected by several small town wastewater and sugar cane industries effluents. Environmental variables were divided in two sets, hereafter named “pollution” and “natural”. The first set included water quality variables modified by anthropic activities such as D.O., C.O.D, and dissolved ion concentrations. Natural variables included altitude, position, and time of the year. The upstream site (S1 had the lowest species richness and CPUE; but the number of species and density increased downriver (S2-S3. S1 was inhabited by invertivore species (Trichomycterus corduvensis, having low tolerance to environmental conditions and high D.O. requirements. S4 sustained the most tolerant and abundant species (Otocinclus vittatus, Corydoras paleatus, enduring the lowest D.O. and the highest C.O.D. A significant Canonical Correspondence Analysis for natural variables showed a gradient of species composition related to altitude and discharge. Water quality degradation by sugar cane factories and urban development, coupled with natural climatic, topographic and hydrological factors explained a significant amount of spatial and temporal variation in fish community structure (@48%.

  17. Nitrogen cycling and community structure of proteobacterial ß-subgroup ammonia-oxidizing bacteria within polluted marine fish farm sediments

    NARCIS (Netherlands)

    McCaig, A.E.; Phillips, C.B.; Stephen, J.R.; Kowalchuk, G.A.; Harvey, S.M.; Herbert, R.A.; Embley, T.M.; Prosser, J.I.

    1999-01-01

    A multidisciplinary approach was used to study the effects of pollution from a marine fish farm on nitrification rates and on the community structure of ammonia-oxidizing bacteria in the underlying sediment. Organic content, ammonium concentrations, nitrification rates, and ammonia oxidizer most-pro

  18. Disentangling the influences of habitat structure and limnological predictors on stream fish communities of a coastal basin, southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Fabio Cop Ferreira

    Full Text Available In stream environments habitat structure and limnological factors interact regulating patterns of energy and material transfer and affecting fish communities. In the coastal basins of Southeastern Brazil, limnological and structural characteristics differ between clear and blackwaters streams. The former have a diversity of substrate types, higher water velocities, and lower water conductivity, while the latter have sandy substrate, tea-colored and acidic waters, and low water velocities. In this study, we verified the relative importance of habitat structure and limnological variables in predicting patterns of variation in stream fish communities. Eight first to third order streams were sampled in the coastal plain of Itanhaém River basin. We captured 34 fish species and verified that community structure was influenced by physical habitat and limnology, being the former more important. A fraction of the variation could not be totally decomposed, and it was assigned to the joint influence of limnology and habitat structure. Some species that were restricted to blackwater streams, may have physiological and behavioral adaptations to deal with the lower pH levels. When we examined only the clearwater streams, all the explained variation in fish community composition was assigned to structural factors, which express specific preferences for different types of habitats.

  19. Baseline assessment of fish communities, benthic macroinvertebrate communities, and stream habitat and land use, Big Thicket National Preserve, Texas, 1999-2001

    Science.gov (United States)

    Moring, J. Bruce

    2003-01-01

    The Big Thicket National Preserve comprises 39,300 hectares in the form of nine preserve units connected by four stream corridor units (with two more corridor units proposed) distributed over the lower Neches and Trinity River Basins of southeastern Texas. Fish and benthic macroinvertebrate data were collected at 15 stream sites (reaches) in the preserve during 1999–2001 for a baseline assessment and a comparison of communities among stream reaches. The fish communities in the preserve were dominated by minnows (family Cyprinidae) and sunfishes (family Centrarchidae). Reaches with smaller channel sizes generally had higher fish species richness than the larger reaches in the Neches River and Pine Island Bayou units of the preserve. Fish communities in geographically adjacent reaches were most similar in overall community structure. The blue sucker, listed by the State as a threatened species, was collected in only one reach—a Neches River reach a few miles downstream from the Steinhagen Lake Dam. Riffle beetles (family Elmidae) and midges (family Chironomidae) dominated the aquatic insect communities at the 14 reaches sampled for aquatic insects in the preserve. The Ephemeroptera, Plecoptera and Trichoptera (EPT) Index, an index sensitive to water-quality degradation, was smallest at the Little Pine Island Bayou near Beaumont reach that is in a State 303(d)-listed stream segment on Little Pine Island Bayou. Trophic structure of the aquatic insect communities is consistent with the river continuum concept with shredder and scraper insect taxa more abundant in reaches with smaller stream channels and filter feeders more abundant in reaches with larger channels. Aquatic insect community metrics were not significantly correlated to any of the stream-habitat or land-use explanatory variables. The percentage of 1990s urban land use in the drainage areas upstream from 12 bioassessment reaches were negatively correlated to the reach structure index, which indicates

  20. Human activities as a driver of spatial variation in the trophic structure of fish communities on Pacific coral reefs.

    Science.gov (United States)

    Ruppert, Jonathan L W; Vigliola, Laurent; Kulbicki, Michel; Labrosse, Pierre; Fortin, Marie-Josée; Meekan, Mark G

    2017-09-25

    Anthropogenic activities such as land-use change, pollution and fishing impact the trophic structure of coral reef fishes, which can influence ecosystem health and function. Although these impacts may be ubiquitous, they are not consistent across the tropical Pacific Ocean. Using an extensive database of fish biomass sampled using underwater visual transects on coral reefs, we modelled the impact of human activities on food webs at Pacific-wide and regional (1,000s-10,000s km) scales. We found significantly lower biomass of sharks and carnivores, where there were higher densities of human populations (hereafter referred to as human activity); however, these patterns were not spatially consistent as there were significant differences in the trophic structures of fishes among biogeographic regions. Additionally, we found significant changes in the benthic structure of reef environments, notably a decline in coral cover where there was more human activity. Direct human impacts were the strongest in the upper part of the food web, where we found that in a majority of the Pacific, the biomass of reef sharks and carnivores were significantly and negatively associated with human activity. Finally, although human-induced stressors varied in strength and significance throughout the coral reef food web across the Pacific, socioeconomic variables explained more variation in reef fish trophic structure than habitat variables in a majority of the biogeographic regions. Notably, economic development (measured as GDP per capita) did not guarantee healthy reef ecosystems (high coral cover and greater fish biomass). Our results indicate that human activities are significantly shaping patterns of trophic structure of reef fishes in a spatially nonuniform manner across the Pacific Ocean, by altering processes that organize communities in both "top-down" (fishing of predators) and "bottom-up" (degradation of benthic communities) contexts. © 2017 John Wiley & Sons Ltd.

  1. Genomic Organization of Repetitive DNA Elements and Its Implications for the Chromosomal Evolution of Channid Fishes (Actinopterygii, Perciformes)

    Science.gov (United States)

    Cioffi, Marcelo de Bello; Bertollo, Luiz Antonio Carlos; Villa, Mateo Andres; de Oliveira, Ezequiel Aguiar; Tanomtong, Alongklod; Yano, Cassia Fernanda; Supiwong, Weerayuth; Chaveerach, Arunrat

    2015-01-01

    Channid fishes, commonly referred to as “snakeheads”, are currently very important in Asian fishery and aquaculture due to the substantial decline in natural populations because of overexploitation. A large degree of chromosomal variation has been found in this family, mainly through the use of conventional cytogenetic investigations. In this study, we analyzed the karyotype structure and the distribution of 7 repetitive DNA sequences in several Channa species from different Thailand river basins. The aim of this study was to investigate the chromosomal differentiation among species and populations to improve upon the knowledge of its biodiversity and evolutionary history. Rearrangements, such as pericentric inversions, fusions and polyploidization, appear to be important events during the karyotypic evolution of this genus, resulting in the chromosomal diversity observed among the distinct species and even among populations of the same species. In addition, such variability is also increased by the genomic dynamism of repetitive elements, particularly by the differential distribution and accumulation of rDNA sequences on chromosomes. This marked diversity is likely linked to the lifestyle of the snakehead fishes and their population fragmentation, as already identified for other fish species. The karyotypic features highlight the biodiversity of the channid fishes and justify a taxonomic revision of the genus Channa, as well as of the Channidae family as a whole, as some nominal species may actually constitute species complexes. PMID:26067030

  2. Genomic Organization of Repetitive DNA Elements and Its Implications for the Chromosomal Evolution of Channid Fishes (Actinopterygii, Perciformes.

    Directory of Open Access Journals (Sweden)

    Marcelo de Bello Cioffi

    Full Text Available Channid fishes, commonly referred to as "snakeheads", are currently very important in Asian fishery and aquaculture due to the substantial decline in natural populations because of overexploitation. A large degree of chromosomal variation has been found in this family, mainly through the use of conventional cytogenetic investigations. In this study, we analyzed the karyotype structure and the distribution of 7 repetitive DNA sequences in several Channa species from different Thailand river basins. The aim of this study was to investigate the chromosomal differentiation among species and populations to improve upon the knowledge of its biodiversity and evolutionary history. Rearrangements, such as pericentric inversions, fusions and polyploidization, appear to be important events during the karyotypic evolution of this genus, resulting in the chromosomal diversity observed among the distinct species and even among populations of the same species. In addition, such variability is also increased by the genomic dynamism of repetitive elements, particularly by the differential distribution and accumulation of rDNA sequences on chromosomes. This marked diversity is likely linked to the lifestyle of the snakehead fishes and their population fragmentation, as already identified for other fish species. The karyotypic features highlight the biodiversity of the channid fishes and justify a taxonomic revision of the genus Channa, as well as of the Channidae family as a whole, as some nominal species may actually constitute species complexes.

  3. Whole Genome Sequencing of the Asian Arowana (Scleropages formosus) Provides Insights into the Evolution of Ray-Finned Fishes.

    Science.gov (United States)

    Austin, Christopher M; Tan, Mun Hua; Croft, Larry J; Hammer, Michael P; Gan, Han Ming

    2015-10-06

    The Asian arowana (Scleropages formosus) is of commercial importance, conservation concern, and is a representative of one of the oldest lineages of ray-finned fish, the Osteoglossomorpha. To add to genomic knowledge of this species and the evolution of teleosts, the genome of a Malaysian specimen of arowana was sequenced. A draft genome is presented consisting of 42,110 scaffolds with a total size of 708 Mb (2.85% gaps) representing 93.95% of core eukaryotic genes. Using a k-mer-based method, a genome size of 900 Mb was also estimated. We present an update on the phylogenomics of fishes based on a total of 27 species (23 fish species and 4 tetrapods) using 177 orthologous proteins (71,360 amino acid sites), which supports established relationships except that arowana is placed as the sister lineage to all teleost clades (Bayesian posterior probability 1.00, bootstrap replicate 93%), that evolved after the teleost genome duplication event rather than the eels (Elopomorpha). Evolutionary rates are highly heterogeneous across the tree with fishes represented by both slowly and rapidly evolving lineages. A total of 94 putative pigment genes were identified, providing the impetus for development of molecular markers associated with the spectacular colored phenotypes found within this species.

  4. Seasonal changes in community composition and trophic structure of fish populations of five salt marshes along the Essex coastline, United Kingdom

    Science.gov (United States)

    Green, Benjamin C.; Smith, David J.; Earley, Sarah E.; Hepburn, Leanne J.; Underwood, Graham J. C.

    2009-11-01

    European intertidal salt marshes are important nursery sites for juvenile fish and crustaceans. Due to the increasing threat of habitat loss, the seasonal changes of salt marsh fish communities need to be understood in order to appreciate the ecological and economic importance of the saltmarsh habitat. This study was the first in Great Britain to investigate the seasonal changes of salt marsh fish communities and the variation in community structure between closely located marsh habitats. Between February 2007 and March 2008, five marshes on three estuaries of the Essex coastline were sampled using flume nets to block off intertidal creeks at high tide. Fourteen fish species were caught. The community overall was dominated by three species that made up 91.6% of the total catch: the common goby Pomatoschistus microps (46.2% of the total catch), juvenile herring Clupea harengus (24.3%), and juvenile and larval sea bass Dicentrarchus labrax (21.2%). Cluster analysis demonstrated clear seasonal patterns, with some community structures unique to specific marshes or estuaries. The marsh fish community shifts from a highly diverse community during spring, to a community dominated by D. labrax and P. microps in autumn, and low diversity during winter months. Gravimetric stomach content analysis of fish community identified three main trophic guilds; macroinvertivores, planktivores and omnivores. The macroinvertivore feeding guild contained D. labrax and P. microps, the two most frequently occurring species. This investigation demonstrates the importance of British salt marshes as nursery habitats for commercial fish species.

  5. Agonistic behavior among three stocked trout species in a novel reservoir fish community

    Science.gov (United States)

    Budy, Phaedra; Hafen, Konrad

    2015-01-01

    The popularity of reservoirs to support sport fisheries has led to the stocking of species that did not co-evolve, creating novel reservoir fish communities. In Utah, the Bear Lake strain of Bonneville Cutthroat Trout Oncorhynchus clarkii utah and tiger trout (female Brown Trout Salmo trutta × male Brook Trout Salvelinus fontinalis) are being more frequently added to a traditional stocking regimen consisting primarily of Rainbow TroutO. mykiss. Interactions between these three predatory species are not well understood, and studies evaluating community interactions have raised concern for an overall decrease of trout condition. To evaluate the potential for negative interactions among these species, we tested aggression in laboratory aquaria using three-species and pairwise combinations at three densities. Treatments were replicated before and after feeding. During the three-species trials Rainbow Trout initiated 24.8 times more aggressive interactions than Cutthroat Trout and 10.2 times more aggressive interactions than tiger trout, and tiger trout exhibited slightly (1.9 times) more aggressive initiations than Cutthroat Trout. There was no significant difference in behavior before versus after feeding for any species, and no indication of increased aggression at higher densities. Although Rainbow Trout in aquaria may benefit from their bold, aggressive behavior, given observations of decreased relative survival in the field, these benefits may be outweighed in reservoirs, possibly through unnecessary energy expenditure and exposure to predators.

  6. Evolution of the sensor fish device for measuring physical conditions in sever hydraulic environments

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Thomas J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Duncan, J. P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2003-03-01

    To assist in deriving biological specifications for design of turbine rehabilitation measures, new “fish-friendly” turbines, and spillway designs and operations, Pacific Northwest National Laboratory (PNNL) scientists have developed and tested an autonomous multi-sensor device called a Sensor Fish that can acquire pressure and tri-axial linear acceleration data during passage through severe hydraulic conditions. The purpose of the Sensor Fish is to characterize physical conditions fish experience during passage through hydro turbines, spill stilling basins, high-discharge outfalls, and other dam passage routes. This report discusses the development and field tests of the Sensor Fish at Rock Island, McNary, The Dalles, Bonneville, and Wanapum dams on the Columbia River and the Prosser Irrigation District on the Yakima River, which have shown that the device can withstand the severe environments of turbine, spill, and fish bypass passage and provide useful environmental data that can ultimately aid in the design and operation of new and existing turbines, spill, and dam fish bypass facilities.

  7. More than one way to be an herbivore: convergent evolution of herbivory using different digestive strategies in prickleback fishes (Stichaeidae).

    Science.gov (United States)

    German, Donovan P; Sung, Aaron; Jhaveri, Parth; Agnihotri, Ritika

    2015-06-01

    In fishes, the evolution of herbivory has occured within a spectrum of digestive strategies, with two extremes on opposite ends: (i) a rate-maximization strategy characterized by high intake, rapid throughput of food through the gut, and little reliance on microbial digestion or (ii) a yield-maximization strategy characterized by measured intake, slower transit of food through the gut, and more of a reliance on microbial digestion in the hindgut. One of these strategies tends to be favored within a given clade of fishes. Here, we tested the hypothesis that rate or yield digestive strategies can arise in convergently evolved herbivores within a given lineage. In the family Stichaeidae, convergent evolution of herbivory occured in Cebidichthys violaceus and Xiphister mucosus, and despite nearly identical diets, these two species have different digestive physiologies. We found that C. violaceus has more digesta in its distal intestine than other gut regions, has comparatively high concentrations (>11 mM) of short-chain fatty acids (SCFA, the endpoints of microbial fermentation) in its distal intestine, and a spike in β-glucosidase activity in this gut region, findings that, when coupled to long retention times (>20 h) of food in the guts of C. violaceus, suggest a yield-maximizing strategy in this species. X. mucosus showed none of these features and was more similar to its sister taxon, the omnivorous Xiphister atropurpureus, in terms of digestive enzyme activities, gut content partitioning, and concentrations of SCFA in their distal intestines. We also contrasted these herbivores and omnivores with other sympatric stichaeid fishes, Phytichthys chirus (omnivore) and Anoplarchus purpurescens (carnivore), each of which had digestive physiologies consistent with the consumption of animal material. This study shows that rate- and yield-maximizing strategies can evolve in closely related fishes and suggests that resource partitioning can play out on the level of

  8. Repeated parallel evolution of parental care strategies within Xenotilapia, a genus of cichlid fishes from Lake Tanganyika.

    Directory of Open Access Journals (Sweden)

    Michael R Kidd

    Full Text Available The factors promoting the evolution of parental care strategies have been extensively studied in experiment and theory. However, most attempts to examine parental care in an evolutionary context have evaluated broad taxonomic categories. The explosive and recent diversifications of East African cichlid fishes offer exceptional opportunities to study the evolution of various life history traits based on species-level phylogenies. The Xenotilapia lineage within the endemic Lake Tanganyika cichlid tribe Ectodini comprises species that display either biparental or maternal only brood care and hence offers a unique opportunity to study the evolution of distinct parental care strategies in a phylogenetic framework. In order to reconstruct the evolutionary relationships among 16 species of this lineage we scored 2,478 Amplified Fragment Length Polymorphisms (AFLPs across the genome. We find that the Ectodini genus Enantiopus is embedded within the genus Xenotilapia and that during 2.5 to 3 million years of evolution within the Xenotilapia clade there have been 3-5 transitions from maternal only to biparental care. While most previous models suggest that uniparental care (maternal or paternal arose from biparental care, we conclude from our species-level analysis that the evolution of parental care strategies is not only remarkably fast, but much more labile than previously expected.

  9. Repeated parallel evolution of parental care strategies within Xenotilapia, a genus of cichlid fishes from Lake Tanganyika.

    Science.gov (United States)

    Kidd, Michael R; Duftner, Nina; Koblmüller, Stephan; Sturmbauer, Christian; Hofmann, Hans A

    2012-01-01

    The factors promoting the evolution of parental care strategies have been extensively studied in experiment and theory. However, most attempts to examine parental care in an evolutionary context have evaluated broad taxonomic categories. The explosive and recent diversifications of East African cichlid fishes offer exceptional opportunities to study the evolution of various life history traits based on species-level phylogenies. The Xenotilapia lineage within the endemic Lake Tanganyika cichlid tribe Ectodini comprises species that display either biparental or maternal only brood care and hence offers a unique opportunity to study the evolution of distinct parental care strategies in a phylogenetic framework. In order to reconstruct the evolutionary relationships among 16 species of this lineage we scored 2,478 Amplified Fragment Length Polymorphisms (AFLPs) across the genome. We find that the Ectodini genus Enantiopus is embedded within the genus Xenotilapia and that during 2.5 to 3 million years of evolution within the Xenotilapia clade there have been 3-5 transitions from maternal only to biparental care. While most previous models suggest that uniparental care (maternal or paternal) arose from biparental care, we conclude from our species-level analysis that the evolution of parental care strategies is not only remarkably fast, but much more labile than previously expected.

  10. Income and nutritional status of the fishing community residing in coastal bay of Bengal: a case study.

    Science.gov (United States)

    Pal, Baidyanath; Chattopadhyay, Manabendu; Maity, Moumita; Mukhopadhyay, Barun; Gupta, Ranjan

    2010-01-01

    This is part of a project on the disadvantaged, marginalized, vulnerable/weaker section of the population and their survival strategy. The paper presents the results of a survey carried out during 2006-07 with the objective of throwing light on the life and living conditions of an economically weaker community such as 'fishing community' residing in the coastal area of Bay of Bengal in West Bengal and Orissa, India, in the context of global scenario. Various scientists have conducted quite a large number of studies to ascertain the income and nutritional status of people in rural India. Very few attempts, however, have been made to investigate in detail regarding the living standards of some specific communities, which are very often referred to, as the 'weaker section' of the people. The people belonging to fishing community are, by and large, not only economically weak in terms of earning and availability of work, the majority of them are not able to procure the minimum nourishment. The present study shows that some notable elements of living conditions such as food, shelter, health etc. matters much more than the conventional income or calorie deficiency. Commonly, the social scientists equate poverty with income or calorie deficiency which may not be the case as is evident from this study. We have hinted some measures to be undertaken to ameliorate the sufferings of the fishing community.

  11. Influence of coral cover and structural complexity on the accuracy of visual surveys of coral-reef fish communities

    KAUST Repository

    Coker, D. J.

    2017-04-20

    Using manipulated patch reefs with combinations of varying live-coral cover (low, medium and high) and structural complexity (low and high), common community metrics (abundance, diversity, richness and community composition) collected through standard underwater visual census techniques were compared with exhaustive collections using a fish anaesthetic (clove oil). This study showed that reef condition did not influence underwater visual census estimates at a community level, but reef condition can influence the detectability of some small and cryptic species and this may be exacerbated if surveys are conducted on a larger scale.

  12. Impact of discards of beam trawl fishing on the nematode community from the Tagus estuary (Portugal)

    Energy Technology Data Exchange (ETDEWEB)

    Franco, M.A. [Marine Biology Section, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent (Belgium); Oceanography Institute, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisboa (Portugal); Steyaert, M. [Marine Biology Section, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent (Belgium); Cabral, H.N. [Oceanography Institute, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisboa (Portugal); Tenreiro, R.; Chambel, L. [Instituto de Ciencia Aplicada e Tecnologia, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisboa (Portugal); Vincx, M. [Marine Biology Section, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent (Belgium); Costa, M.J. [Oceanography Institute, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisboa (Portugal); Vanaverbeke, J. [Marine Biology Section, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent (Belgium)], E-mail: jan.vanaverbeke@ugent.be

    2008-10-15

    The impact of dead discards, originating from beam trawl fishing on the nematode community from the Tagus estuary was investigated in terms of vertical distribution of the dominant nematode groups. Sediment cores were collected from a mud-flat from the Tagus estuary. Crangoncrangon (Linnaeus, 1758) carcasses were added to the surface of the cores, simulating the settling of dead discards on the sediment. The vertical distribution of the dominant nematode groups was determined up to 4 cm deep at four different moments in time post deposition (0, 2, 4 and 6 h) and compared to control cores. The C.crangon addition to the sediment led to the formation of black spots and therefore oxygen depleted areas at the sediment surface. The Chromadora/Ptycholaimellus group, normally dominant at the surface layer, migrated downwards due to their high sensibility to toxic conditions. Sabatieria presented the opposite trend and became the dominant group at the surface layer. Since Sabatieria is tolerant to oxygen stressed conditions and high sulphide concentrations, we suggest that it migrated opportunistically towards an unoccupied niche. Daptonema, Metachromadora and Terschellingia did not show any vertical migration, reflecting their tolerance to anoxic and high sulphidic conditions. Our study showed that an accumulation of dead discards at the sediment surface might therefore alter the nematode community vertical distribution. This effect is apparently closely related to toxic conditions in the sediment, induced by the deposition of C.crangon at the sediment surface. These alterations might be temporal and reflect an adaptation of the nematode community to dynamic intertidal environments.

  13. Impact of discards of beam trawl fishing on the nematode community from the Tagus estuary (Portugal).

    Science.gov (United States)

    Franco, M A; Steyaert, M; Cabral, H N; Tenreiro, R; Chambel, L; Vincx, M; Costa, M J; Vanaverbeke, J

    2008-10-01

    The impact of dead discards, originating from beam trawl fishing on the nematode community from the Tagus estuary was investigated in terms of vertical distribution of the dominant nematode groups. Sediment cores were collected from a mud-flat from the Tagus estuary. Crangoncrangon (Linnaeus, 1758) carcasses were added to the surface of the cores, simulating the settling of dead discards on the sediment. The vertical distribution of the dominant nematode groups was determined up to 4cm deep at four different moments in time post deposition (0, 2, 4 and 6h) and compared to control cores. The C.crangon addition to the sediment led to the formation of black spots and therefore oxygen depleted areas at the sediment surface. The Chromadora/Ptycholaimellus group, normally dominant at the surface layer, migrated downwards due to their high sensibility to toxic conditions. Sabatieria presented the opposite trend and became the dominant group at the surface layer. Since Sabatieria is tolerant to oxygen stressed conditions and high sulphide concentrations, we suggest that it migrated opportunistically towards an unoccupied niche. Daptonema, Metachromadora and Terschellingia did not show any vertical migration, reflecting their tolerance to anoxic and high sulphidic conditions. Our study showed that an accumulation of dead discards at the sediment surface might therefore alter the nematode community vertical distribution. This effect is apparently closely related to toxic conditions in the sediment, induced by the deposition of C.crangon at the sediment surface. These alterations might be temporal and reflect an adaptation of the nematode community to dynamic intertidal environments.

  14. A description of the nearshore fish communities in the Huron-Erie Corridor using multiple gear types

    Science.gov (United States)

    Francis, James T.; Chiotti, Justin A.; Boase, James C.; Thomas, Mike V.; Manny, Bruce A.; Roseman, Edward F.

    2013-01-01

    Great Lakes coastal wetlands provide a critical habitat for many fish species throughout their life cycles. Once home to one of the largest wetland complexes in the Great Lakes, coastal wetlands in the Huron–Erie Corridor (HEC) have decreased dramatically since the early 1900s. We characterized the nearshore fish communities at three different wetland complexes in the HEC using electrofishing, seines, and fyke nets. Species richness was highest in the Detroit River (63), followed by the St. Clair Delta (56), and Western Lake Erie (47). The nearshore fish communities in the Detroit River and St. Clair Delta consisted primarily of shiners, bluntnose minnow, centrarchids, and brook silverside, while the Western Lake Erie sites consisted of high proportions of non-native taxa including common carp, gizzard shad, goldfish, and white perch. Species richness estimates using individual-based rarefaction curves were higher when using electrofishing data compared to fyke nets or seine hauls at each wetland. Twelve fish species were captured exclusively during electrofishing assessments, while one species was captured exclusively in fyke nets, and none exclusively during seine hauls. Western Lake Erie wetlands were more indicative of degraded systems with lower species richness, lower proportion of turbidity intolerant species, and increased abundance of non-native taxa. This work highlights the importance of coastal wetlands in the HEC by capturing 69 different fish species utilizing these wetlands to fulfill life history requirements and provides insight when selecting gears to sample nearshore littoral areas.

  15. The evolution of the Fenway Community Health model.

    Science.gov (United States)

    Mayer, K; Appelbaum, J; Rogers, T; Lo, W; Bradford, J; Boswell, S

    2001-06-01

    Fenway Community Health was founded by community activists in 1971 in the Fenway neighborhood of Boston, Mass, and within a decade had rapidly expanded its medical services for gay men in response to the AIDS epidemic. Increased expertise and cultural competence in lesbian, gay, bisexual, and transgender (LGBT) care led to expansion of medical services to address broader community concerns, ranging from substance use to parenting issues to domestic and homophobic violence, as well as specialized programs for lesbians, bisexuals, and transgendered individuals. Fenway began as a grassroots neighborhood clinic. In 1975, the center recorded 5000 patient care visits; in 2000, Fenway's clinical departments recorded 50,850 visits by 8361 individuals, including more than 1100 individuals receiving HIV-associated care. The center now has more than 170 staff people responsible for clinical programs, community education, research, administration, planning, and development. Over the past few years, Fenway's annual budget has exceeded $10 million. Fenway has established standards for improved cultural competence about LGBT health issues for other health providers and has developed programs to educate the general community about specific LGBT health concerns. This health center may provide a model of comprehensive LGBT health services that have a local impact.

  16. The Importance of Being Cis: Evolution of Orthologous Fish and Mammalian Enhancer Activity

    OpenAIRE

    Ritter, Deborah I.; Li, Qiang; Kostka, Dennis; Pollard, Katherine S.; Guo, Su; Chuang, Jeffrey H.

    2010-01-01

    Conserved noncoding elements (CNEs) in vertebrate genomes often act as developmental enhancers, but a critical issue is how well orthologous CNE sequences retain the same activity in their respective species, a characteristic important for generalization of model organism studies. To quantify how well CNE enhancer activity has been preserved, we compared the anatomy-specific activities of 41 zebra fish CNEs in zebra fish embryos with the activities of orthologous human CNEs in mouse embryos. ...

  17. Zebra fish myc family and max genes: differential expression and oncogenic activity throughout vertebrate evolution.

    OpenAIRE

    Schreiber-Agus, N; Horner, J.; Torres, R.; Chiu, F C; Depinho, R.A.

    1993-01-01

    To gain insight into the role of Myc family oncoproteins and their associated protein Max in vertebrate growth and development, we sought to identify homologs in the zebra fish (Brachydanio rerio). A combination of a polymerase chain reaction-based cloning strategy and low-stringency hybridization screening allowed for the isolation of zebra fish c-, N-, and L-myc and max genes; subsequent structural characterization showed a high degree of conservation in regions that encode motifs of known ...

  18. Changes in the fish community structure after the implementation of Marine Protected Areas in the south western coast of Portugal

    Directory of Open Access Journals (Sweden)

    Tadeu J. Pereira

    2015-10-01

    Full Text Available Marine Protected Areas (MPAs are increasingly being recommended as management tools for biodiversity conservation and fisheries. With the purpose of protecting the region’s biodiversity and prevent the over exploitation of marine resources, in February 2011 the MPAs of Ilha do Pessegueiro and Cabo Sardão were implemented in the “Parque Natural do Sudoeste Alentejano e Costa Vicentina “(PNSACV Natural Park, south western coast of Portugal. In these areas, commercial and recreational fishing became prohibited. In order to evaluate the effects of these MPAs, the structure of its fish communities and of adjacent control areas without fishing restrictions were studied in 2011/12 (immediately after implementation and 2013 (two years after implementation. A total of 4 sampling campaigns were conducted (summer 2011, winter 2012, summer 2013 and winter 2013 using bottom trawl and gillnets. Faunal communities from the MPAs (treatment were compared with adjacent areas (controls and changes evaluated with time. Results revealed significant changes on abundance, having this parameter a slight increase after the implementation of the MPAs. Also, significant differences were observed on the structure of the protected areas communities when compared with neighbouring areas where fishing was still allowed, even though the small amount of time elapsed. In addition, specimens of larger size occurred more frequently within Ilha do Pessegueiro MPA in the last year of the study. Despite the young age of these MPAs, changes on their fish communities’ structure are already visible after only 3 years of protection, showing that these management measures may promote sustainable exploitation of fishing resources as well as protect species with conservation interest, thus leading to a global biodiversity increase.

  19. Microbial community development of biofilm in Amaranth decolourization technology analysed by FISH

    Science.gov (United States)

    Belouhova, Mihaela; Schneider, Irina; Chakarov, Stoyan; Ivanova, Iliana; Topalova, Yana

    2014-01-01

    The aim of this study was to elucidate the role, the space distribution and the relationships of the bacteria from the genus Pseudomonas in a biofilm community during semi-continuous Amaranth decolourization process in model sand biofilters. The examined parameters of the process were as follows: technological parameters; key enzyme activities (azoreductase, succinate dehydrogenase, catechol-1,2-dioxygenase, catechol-2,3-dioxygenase); the number of azo-degrading bacteria and the bacteria from genus Pseudomonas (plate count technique); the amount and the location of Pseudomonas sp. using fluorescent in situ hybridization (FISH). The results showed that the increase of the Amaranth removal rate with 120% was accompanied with increase of the enzyme activities of the biofilm (azoreductase activity – with 25.90% and succinate dehydrogenase – with 10.61%). The enzyme assays showed absence of activity for сatechol-1,2-dioxygenase and catechol-2,3-dioxygenase at the early phase and high activities of the same oxygenases at the late phase (2.76 and 1.74 μmol/min mg protein, respectively). In the beginning of the process (0–191 h), the number of the culturable microorganisms from genus Pseudomonas was increased with 48.76% but at the late phase (191–455 h) they were decreased with 15.25% while the quantity of the non-culturable bacteria from this genus with synergetic relationships was increased with 23.26%. The dominant microbial factors were identified in the structure of the biofilm during the azo-degradation process by using FISH analysis. Furthermore, the inner mechanisms for increase of the rate and the range of the detoxification were revealed during the complex wastewater treatment processes. PMID:26019551

  20. The influence of flood pulse on fish communities of floodplain canals in the Middle Solimões River, Brazil

    Directory of Open Access Journals (Sweden)

    Raniere G. C. Sousa

    Full Text Available The functioning of large river systems with adjacent floodplains is strongly influenced by the flood pulse. This phenomenon is the main structuring force for the biota, including fish communities that use floodplain environments for spawning, feeding, nursery and refuge. In floodplains and in the entire basin, the volume of water controls internal flows. During rising water, the high discharge of the river acts as a natural barrier to the canals that connect floodplain lakes and the Solimões River, because the water flows from river to lake. During the dry period, there is a reduction of discharge and the water flow is reversed or stationary. These canals are environments with distinct ecological characteristics such as differentiated limnology and water level variation intensely affected by the hydrological cycle. Therefore, we surveyed the influence of the flood pulse on fish communities that inhabit two canals that connect floodplain lakes to the Middle Solimões River. Particularly, we evaluated the hypothesis that the Solimões River flow direction is not perfectly parallel to its banks, which creates peripheral flows that direct water from the rivers to the floodplain lake canals. Our analysis indicated that the seasonal pattern is stronger than the spatial. Beside this, we observed that the positions of the canals in relation to the main river flow somehow affect the fish assemblages. Finally, we conclude that the flood pulse is the main structuring force acting on these fish communities.

  1. How will coral reef fish communities respond to climate-driven disturbances? Insight from landscape-scale perturbations.

    Science.gov (United States)

    Adam, Thomas C; Brooks, Andrew J; Holbrook, Sally J; Schmitt, Russell J; Washburn, Libe; Bernardi, Giacomo

    2014-09-01

    Global climate change is rapidly altering disturbance regimes in many ecosystems including coral reefs, yet the long-term impacts of these changes on ecosystem structure and function are difficult to predict. A major ecosystem service provided by coral reefs is the provisioning of physical habitat for other organisms, and consequently, many of the effects of climate change on coral reefs will be mediated by their impacts on habitat structure. Therefore, there is an urgent need to understand the independent and combined effects of coral mortality and loss of physical habitat on reef-associated biota. Here, we use a unique series of events affecting the coral reefs around the Pacific island of Moorea, French Polynesia to differentiate between the impacts of coral mortality and the degradation of physical habitat on the structure of reef fish communities. We found that, by removing large amounts of physical habitat, a tropical cyclone had larger impacts on reef fish communities than an outbreak of coral-eating sea stars that caused widespread coral mortality but left the physical structure intact. In addition, the impacts of declining structural complexity on reef fish assemblages accelerated as structure became increasingly rare. Structure provided by dead coral colonies can take up to decades to erode following coral mortality, and, consequently, our results suggest that predictions based on short-term studies are likely to grossly underestimate the long-term impacts of coral decline on reef fish communities.

  2. The community composition and production of phytoplankton in fish pens of Cape Bolinao, Pangasinan: a field study.

    Science.gov (United States)

    Yap, Leni G; Azanza, Rhodora V; Talaue-McManus, Liana

    2004-11-01

    From 1995 up to the present, fish pens proliferated in the municipal waters of Bolinao, northern Philippines. Since then, fish kills and phytoplankton blooms have been recurrent. Have fishpens altered the phytoplankton community composition and production of these waters? The phytoplankton community in Cape Bolinao, Lingayen Gulf is typical of a tropical coastal area where diatoms alternate with dinoflagellates during the dry and wet seasons. In the nutrient-rich fish pens, phytoplankton in this study showed a lower diatom/dinoflagellate ratio and unusually high phytoplankton counts of 10(4) cells/l and even as high as 10(5) cells/l. Correlations between physico-chemical parameters, phytoplankton production and community composition were made in 2001. This paper tried to explain the occurrence of a Cylindrotheca closterium bloom (10(5) cells/l), during the dry season of the same year and a Prorocentrum minimum bloom (4.7 x 10(5) cells/l), which accompanied a massive fish kill during January 2002.

  3. The community composition and production of phytoplankton in fish pens of Cape Bolinao, Pangasinan: a field study

    Energy Technology Data Exchange (ETDEWEB)

    Yap, Leni G. [University of the Philippines in the Visayas, Tacloban College, Tacloban City, Leyte 6500 (Philippines)]. E-mail: leni@upmsi.ph; Azanza, Rhodora V. [Marine Science Institute, University of the Philippines, Diliman, Quezon City 1101 (Philippines)]. E-mail: rhod@upmsi.ph; Talaue-McManus, Liana [Division of Marine Affairs, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149 (United States)]. E-mail: lmcmanus@rsmas.miami.edu

    2004-11-01

    From 1995 up to the present, fish pens proliferated in the municipal waters of Bolinao, northern Philippines. Since then, fish kills and phytoplankton blooms have been recurrent. Have fishpens altered the phytoplankton community composition and production of these waters? The phytoplankton community in Cape Bolinao, Lingayen Gulf is typical of a tropical coastal area where diatoms alternate with dinoflagellates during the dry and wet seasons. In the nutrient-rich fish pens, phytoplankton in this study showed a lower diatom/dinoflagellate ratio and unusually high phytoplankton counts of 10{sup 4} cells/l and even as high as 10{sup 5} cells/l. Correlations between physico-chemical parameters, phytoplankton production and community composition were made in 2001. This paper tried to explain the occurrence of a Cylindrotheca closterium bloom (10{sup 5} cells/l), during the dry season of the same year and a Prorocentrum minimum bloom (4.7 x 10{sup 5} cells/l), which accompanied a massive fish kill during January 2002.

  4. Microbial community succession mechanism coupling with adaptive evolution of adsorption performance in chalcopyrite bioleaching.

    Science.gov (United States)

    Feng, Shoushuai; Yang, Hailin; Wang, Wu

    2015-09-01

    The community succession mechanism of Acidithiobacillus sp. coupling with adaptive evolution of adsorption performance were systematically investigated. Specifically, the μmax of attached and free cells was increased and peak time was moved ahead, indicating both cell growth of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans was promoted. In the mixed strains system, the domination courses of A. thiooxidans was dramatically shortened from 22th day to 15th day, although community structure finally approached to the normal system. Compared to A. ferrooxidans, more positive effects of adaptive evolution on cell growth of A. thiooxidans were shown in either single or mixed strains system. Moreover, higher concentrations of sulfate and ferric ions indicated that both sulfur and iron metabolism was enhanced, especially of A. thiooxidans. Consistently, copper ion production was improved from 65.5 to 88.5 mg/L. This new adaptive evolution and community succession mechanism may be useful for guiding similar bioleaching processes.

  5. Impact of mass coral bleaching on reef fish community and fishermen catches at Sabang, Aceh Province, Indonesia

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    Edi Rudi

    2012-12-01

    Full Text Available Mass coral bleaching was observed at Sabang, Aceh in early 2010, and approximately 60% ofhard coral in waters surrounding Sabang died post-event. Coral mortality was expected to affect thecomposition of reef fish due to decrease its function such as providing a shelter, feeding and spawninggrounds for fish and other marine organisms. The objectives of this research were to evaluate the impactof coral bleaching on coral reef fish community and to compare the composition of fishermen catchesbefore and after the coral bleaching. The data were collected before (in 2008 and after (in 2010 themass coral bleaching event in Sabang waters by using a photographic method and the data on theaverage catch of fishermen (catch per fishing effort was calculated in kg/hour. The data of theknowledge of fishermen on climate change was collected by questionnaire method. The results showedthat 259 species of coral reef fishes were caught by fishermen in 2008 and 2010. There was nosignificantly difference between the fish catches before and after the mass coral bleaching. However,species richness decreased up to 50% after the mass coral bleaching. The knowledge of fishermen onclimate change issue was very low.

  6. Aquatic insects as the main food resource of fish the community in a Neotropical reservoir

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    Ana Paula Vidotto-Magnoni

    2009-01-01

    Full Text Available We evaluated the feeding of fish species of the Nova Avanhandava Reservoir, low Tietê River, São Paulo State, Brazil. Fishes were collected in two stretches of the reservoir: Santa Bárbara (14 samples and Bonito (two samples between September 2002 and March 2004, using gill and seining nets. The results of stomach contents analysis were expressed with the frequency of occurrence and gravimetric method, combined in the Alimentary Index (AI. The 20 species studied consumed 52 food items, grouped in 10 food categories: aquatic insects, terrestrial insects, crustaceans, fish, macroinvertebrates, microcrustaceans, algae, vegetal matter, detritus/sediment and scales. The aquatic insects (mainly Chironomidae, Odonata and Ephemeroptera were the most common food resources, consumed by 18 species. The diet composition of the community (species grouped indicated that the dominant food category in the diet of fishes was aquatic insects (AI = 77.6%, followed by crustaceans (AI = 7.1%. Four trophic guilds were identified according a cluster analysis (Pearson distance: insectivorous (10 species, omnivorous (4 species, detritivorous (3 species and piscivorous/carcinophagous (3 species. Despite the highest number of species, the insectivorous guild was responsible for more than 80% in captures in number and biomass (CPUEn and CPUEb. The low values of niche breadth presented by all species, along with the low values of diet overlap between species pairs indicate a high degree of food resources partitioning among species. The aquatic insects, despite being the main food resource of insectivorous fishes, also complemented the diet of other species, which demonstrate the importance of this food resource for the fish community, sustaining a high diversity, abundance and biomass of fishes.Neste estudo foi avaliada a dieta das espécies de peixes do reservatório de Nova Avanhandava, baixo rio Tietê, Estado de São Paulo, Brasil. Os peixes foram coletados em dois

  7. Convergent evolution of modularity in metabolic networks through different community structures.

    Science.gov (United States)

    Zhou, Wanding; Nakhleh, Luay

    2012-09-14

    It has been reported that the modularity of metabolic networks of bacteria is closely related to the variability of their living habitats. However, given the dependency of the modularity score on the community structure, it remains unknown whether organisms achieve certain modularity via similar or different community structures. In this work, we studied the relationship between similarities in modularity scores and similarities in community structures of the metabolic networks of 1021 species. Both similarities are then compared against the genetic distances. We revisited the association between modularity and variability of the microbial living environments and extended the analysis to other aspects of their life style such as temperature and oxygen requirements. We also tested both topological and biological intuition of the community structures identified and investigated the extent of their conservation with respect to the taxonomy. We find that similar modularities are realized by different community structures. We find that such convergent evolution of modularity is closely associated with the number of (distinct) enzymes in the organism's metabolome, a consequence of different life styles of the species. We find that the order of modularity is the same as the order of the number of the enzymes under the classification based on the temperature preference but not on the oxygen requirement. Besides, inspection of modularity-based communities reveals that these communities are graph-theoretically meaningful yet not reflective of specific biological functions. From an evolutionary perspective, we find that the community structures are conserved only at the level of kingdoms. Our results call for more investigation into the interplay between evolution and modularity: how evolution shapes modularity, and how modularity affects evolution (mainly in terms of fitness and evolvability). Further, our results call for exploring new measures of modularity and network

  8. Convergent evolution of modularity in metabolic networks through different community structures

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    Zhou Wanding

    2012-09-01

    Full Text Available Abstract Background It has been reported that the modularity of metabolic networks of bacteria is closely related to the variability of their living habitats. However, given the dependency of the modularity score on the community structure, it remains unknown whether organisms achieve certain modularity via similar or different community structures. Results In this work, we studied the relationship between similarities in modularity scores and similarities in community structures of the metabolic networks of 1021 species. Both similarities are then compared against the genetic distances. We revisited the association between modularity and variability of the microbial living environments and extended the analysis to other aspects of their life style such as temperature and oxygen requirements. We also tested both topological and biological intuition of the community structures identified and investigated the extent of their conservation with respect to the taxomony. Conclusions We find that similar modularities are realized by different community structures. We find that such convergent evolution of modularity is closely associated with the number of (distinct enzymes in the organism’s metabolome, a consequence of different life styles of the species. We find that the order of modularity is the same as the order of the number of the enzymes under the classification based on the temperature preference but not on the oxygen requirement. Besides, inspection of modularity-based communities reveals that these communities are graph-theoretically meaningful yet not reflective of specific biological functions. From an evolutionary perspective, we find that the community structures are conserved only at the level of kingdoms. Our results call for more investigation into the interplay between evolution and modularity: how evolution shapes modularity, and how modularity affects evolution (mainly in terms of fitness and evolvability. Further, our results

  9. Temporal dynamics of a fish community in the lower portion of a tidal creek, Pando sub-estuarine system, Uruguay

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    Rodrigo Gurdek

    Full Text Available ABSTRACT Estuaries are highly dynamic ecosystems subjected to variability of their fish communities over different time scales. The nearshore fish community of the lower Pando estuary, a temperate sub-system of the Río de la Plata estuary, was sampled from May 2002 to June 2003. A total of 2,165 fishes, represented by 16 species were caught by seine netting. Captures were dominated by juveniles (>90%, as well as by the sciaenid Micropogonias furnieri (Desmarest, 1823 (82.8%. The fish community showed high seasonal variability, with the greatest diversity and biomass in summer and spring and the highest species richness during summer. Lowest values of all community parameters occurred in winter and autumn, seasons that presented the highest similarity in fish composition. Number of species was correlated with water temperature and salinity. The ichthyofaunal composition showed significant diel differences in summer and spring. Diel changes were observed in the density of M. furnieri and Odontesthes argentinensis (Valenciennes, 1835, occurring mainly during the day, and of Mugil liza Valenciennes, 1836, Parapimelodus valenciennis (Lütken, 1874 and Brevoortia aurea (Spix & Agassiz, 1829, caught mostly during the night. Temporal variability was attributed to environmental fluctuations, life cycle of species as well as to feeding patterns and small-scale displacements. Presented findings in the Pando sub-estuary denote similar juvenile use and seasonal patterns to those found in estuaries. Further studies in the nursery function and juvenile dynamics over the year are recommended in order to better understand the ecological role of sub-estuaries.

  10. Community structure of age-0 fishes in paired mainstem and created shallow-water habitats in the Lower Missouri River

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    Starks, T. A.; Long, James M.; Dzialowski, Andrew R.

    2016-01-01

    Anthropogenic alterations to aquatic ecosystems have greatly reduced and homogenized riverine habitat, especially those used by larval and juvenile fishes. Creation of shallow-water habitats is used as a restoration technique in response to altered conditions in several studies globally, but only recently in the USA. In the summer of 2012, the U.S. Army Corps of Engineers sampled larval and juvenile fishes at six paired sites (mainstem and constructed chute shallow-water habitats) along a section of the Missouri River between Rulo, NE and St. Louis, MO, USA. From those samples, we enumerated and identified a total of 7622 fishes representing 12 families. Community responses of fishes to created shallow-water habitats were assessed by comparisons of species richness and diversity measures between paired sites and among sampling events. Shannon entropy measures were transformed, and gamma diversity (total diversity) was partitioned into two components, alpha (within community) and beta (between community) diversity using a multiplicative decomposition method. Mantel test results suggest site location, time of sampling event and habitat type were drivers of larval and juvenile community structure. Paired t-test results indicated little to no differences in beta diversity between habitat types; however, chute habitats had significantly higher alpha and gamma diversity as well as increased abundances of Asian carp larvae when compared with mainstem shallow-water habitat. Our results not only show the importance of created shallow-water habitat in promoting stream fish diversity but also highlight the role space and time may play in future restoration and management efforts. 

  11. Evaluating seasonal dynamics of bacterial communities in marine fish aquaculture: a preliminary study before applying phage therapy.

    Science.gov (United States)

    Pereira, Carla; Salvador, Sara; Arrojado, Cátia; Silva, Yolanda; Santos, Ana L; Cunha, Angela; Gomes, Newton C M; Gomes, Newton; Almeida, Adelaide

    2011-04-01

    The increasing problem of antibiotic resistance in common pathogenic bacteria and the concern about the spreading of antibiotics in the environment bring the need to find new methods to control fish pathogens. Phage therapy represents a potential alternative to antibiotics, but its use in aquaculture requires a detailed understanding of bacterial communities, namely of fish pathogenic bacteria. Therefore, in this study the seasonal dynamics of the overall bacterial communities, microbiological water quality and disease-causing bacteria were followed in a marine aquaculture system of Ria de Aveiro (Portugal). Analysis of the bacterial diversity of the water samples by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments indicates that the bacterial community structure varied seasonally, showing a higher complexity during the warm season. The diversity of the main fish pathogenic bacteria, assessed by DGGE targeting the Vibrio genus, showed lower seasonal variation, with new dominating populations appearing mainly in the spring. Bacterial indicators, faecal coliforms and enterococci, enumerated by the filter-membrane method, also varied seasonally. The fluorescent in situ hybridization (FISH) results showed that the specific groups of bacteria varied during the study period and that the non-indigenous Enterobactereaceae family was the most abundant group followed by Vibrio and Aeromonas. The seasonal variation detected in terms of density and structure of total and pathogenic bacterial communities demonstrates the need for a careful monitoring of water through the year in order to select the suitable phages to inactivate fish pathogenic bacteria. The spring season seems to be the critical time period when phage therapy should be applied.

  12. The Impacts of Recently Established Fish Populations on Zooplankton Communities in a Desert Spring, and Potential Conflicts in Setting Conservation Goals

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    Sujan M. Henkanaththegedara

    2015-01-01

    Full Text Available Desert springs, which harbor diverse and endemic invertebrate assemblages, are often used as refuge habitats for protected fish species. Additionally, many of these springs have been colonized by invasive fish species. However, the potential impacts of recently established fish populations on invertebrate communities in desert springs have been relatively unexplored. We conducted a mesocosm experiment to assess the impact of both protected and invasive fish on community structure of spring-dwelling invertebrates focusing on zooplankton. Experimental populations of spring zooplankton communities were established and randomly assigned to one of three treatments, (1 invasive western mosquitofish (Gambusia affinis; (2 endangered Mohave tui chub (Siphateles bicolor mohavensis; and (3 fishless control. Final populations of zooplankton and fish were sampled, sorted, identified and counted. The treatment differences of zooplankton communities were analyzed by comparing the densities of six major zooplankton taxa. Further, we performed nonmetric multidimensional scaling (NMDS to visualize the patterns of zooplankton community assemblages. Four zooplankton taxa, crustacean nauplii, cladocera, calanoid and cyclopoid copepods had significantly lower densities in fish treatments compared to fishless control. Overall, invasive mosquitofish caused a 78.8% reduction in zooplankton density, while Mohave tui chub caused a 65.1% reduction. Both protected and invasive fish had similar effects on zooplankton except for cladocerans where tui chub caused a 60% reduction in density, whereas mosquitofish virtually eliminated cladocerans. The presence of fish also had a significant effect on zooplankton community structure due to population declines and local extirpations presumably due to fish predation. This work shows that conservation-translocations undertaken to conserve protected fish species may impact spring-dwelling invertebrate communities, and such impacts are

  13. Evolution of TQM Principles and Practices at Jackson Community College.

    Science.gov (United States)

    LeTarte, Clyde E.; Schwinn, Carole J.

    1994-01-01

    Describes the Total Quality Management (TQM) effort undertaken three years ago by Jackson Community College (JCC), in Michigan. Discusses the history of JCC, its early TQM efforts, the basic tenets of TQM, steps taken by JCC to integrate TQM practices into its evaluation methods, and benefits of TQM. (MAB)

  14. Evolution of TQM Principles and Practices at Jackson Community College.

    Science.gov (United States)

    LeTarte, Clyde E.; Schwinn, Carole J.

    1994-01-01

    Describes the Total Quality Management (TQM) effort undertaken three years ago by Jackson Community College (JCC), in Michigan. Discusses the history of JCC, its early TQM efforts, the basic tenets of TQM, steps taken by JCC to integrate TQM practices into its evaluation methods, and benefits of TQM. (MAB)

  15. The Evolution of Social and Semantic Networks in Epistemic Communities

    Science.gov (United States)

    Margolin, Drew Berkley

    2012-01-01

    This study describes and tests a model of scientific inquiry as an evolving, organizational phenomenon. Arguments are derived from organizational ecology and evolutionary theory. The empirical subject of study is an "epistemic community" of scientists publishing on a research topic in physics: the string theoretic concept of…

  16. The impact of thermal energy and materials derived from the hot spring drainage on the fish community near the estuary

    Science.gov (United States)

    Yamada, M.; Shoji, J.; Mishima, T.; Honda, H.; Fujii, M.; Ohsawa, S.; Taniguchi, M.

    2014-12-01

    Beppu is a region with many hot springs in Japan. Some of environmental studies of the rivers in this region (e.g. Kawano et al., 1998, Ohsawa et al., 2008) show that hot spring drainage flows into a river and then flow into the coastal are, and it strongly affects the river water quality. On the other hands, several kinds of tropical fish lives in those rivers (Hiramatu et al., 1995). We can easily have watched those fish there. Although the relationship between hot spring drainage and the fish community had not been investigated in the past in this area, it is easily assumed that thermal energy and materials derived from the hot spring drainage strongly affect the ecosystem. However, the impact of the hot spring drainage on the ecosystem in river and coastal area is not clear. We investigated the river water quality and physical property of six rivers in this region. Additionally, we investigated the fish community near the estuary at two rivers which are strongly affected by the hot spring drainage and not the influence of the hot spring at all. We tried an evaluation about the influence of thermal energy and materials derived from the hot spring drainage on the fish community near the estuary.The results of chemical and physical data in these rivers are as follows. The size of influence of hot spring drainage on river is different every river. In this region, Hirata River is most strongly affected by the hot spring drainage. The water temperature of Hirata River maintains 25 degrees Celsius or more through the year and the concentrations of dissolved component is very high. On the other hand, the water temperature and the concentrations of dissolved component of Hiya Rive is low. These data are similar to data of the upper side of Hirata River. The results of investigating the fish community indicate that Oreochromis niloticus and Rhinogobius giurinus is the dominant species at Hirata River and Hiya River respectively. In addition, there is more the number of

  17. MERCURY EXPOSURE FROM FISH CONSUMPTION WITHIN THE JAPANESE AND KOREAN COMMUNITIES

    Science.gov (United States)

    Public health guidance pertaining to fish consumption requires that we be cognizant of the health concerns associated with eating contaminated fish and the nutritional benefits obtained from fish consumption. In doing so, a need exists for an improved understanding of the extent ...

  18. Changes in fish communities on a small spatial scale, an effect of increased habitat complexity by an offshore wind farm.

    Science.gov (United States)

    van Hal, R; Griffioen, A B; van Keeken, O A

    2017-05-01

    The number of offshore wind farms (OWF) is increasing to meet the demands for renewable energy. The piles and hard substrate surrounding these piles creates new habitat for species with preference to hard substrates. We studied the impact of this hard substrate on the fish community in a Dutch OWF in the sandy southern North Sea, which had been in operation for five years. Multi-mesh gillnets were placed near the OWF structures on the hard substrate protection revetments and on the sandy bottom in the middle of the farm. The catches indicated attraction of cod, pouting, bullrout and edible and velvet crab, while attraction to the sandy habitat was shown for flatfish and whiting. Further, two species previously not caught in this area, goldsinny wrasse and grey trigger fish, were caught on the hard substrate. In addition a Dual-Frequency Identification Sonar (DIDSON) was used to record transects through the farm to observe individual fish in the water column throughout the farm and very near the OWF structures. High abundances of fish near the structure were observed during some days, while during other days equal distribution of fish in the area was observed. The area around the structures is thus only used temporarily for shelter or feeding. The DIDSON also allowed looking at the aggregation level of the fish. Seasonally the aggregation level differed most likely due to different species occurring in the area. In April, most fish were aggregated in schools, while in summer most observations were individual fish or loose aggregations. The wind farm structures had limited effect on the aggregation level compared to season or weather conditions.

  19. Bacteriophages with Potential for Inactivation of Fish Pathogenic Bacteria: Survival, Host Specificity and Effect on Bacterial Community Structure

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    Yolanda J. Silva

    2011-11-01

    Full Text Available Phage therapy may represent a viable alternative to antibiotics to inactivate fish pathogenic bacteria. Its use, however, requires the awareness of novel kinetics phenomena not applied to conventional drug treatments. The main objective of this work was to isolate bacteriophages with potential to inactivate fish pathogenic bacteria, without major effects on the structure of natural bacterial communities of aquaculture waters. The survival was determined in marine water, through quantification by the soft agar overlay technique. The host specificity was evaluated by cross infection. The ecological impact of phage addition on the structure of the bacterial community was evaluated by DGGE of PCR amplified 16S rRNA gene fragments. The survival period varied between 12 and 91 days, with a higher viability for Aeromonas salmonicida phages. The phages of Vibrio parahaemolyticus and of A. salmonicida infected bacteria of different families with a high efficacy of plating. The specific phages of pathogenic bacteria had no detectable impact on the structure of the bacterial community. In conclusion, V. parahaemolyticus and A. salmonicida phages show good survival time in marine water, have only a moderated impact on the overall bacterial community structure and the desired specificity for host pathogenic bacteria, being potential candidates for therapy of fish infectious diseases in marine aquaculture systems.

  20. Mitogenomic perspectives into sciaenid fishes' phylogeny and evolution origin in the New World.

    Science.gov (United States)

    Xu, Tianjun; Tang, Da; Cheng, Yuanzhi; Wang, Rixin

    2014-04-10

    Sciaenid fishes are widely distributed throughout the coastal waters and estuaries of the world. A total of 23 genera of this family are endemic to the Old World. However, evolutionary relationships among Old World sciaenid fishes and their origin have remained unresolved despite their diversity and importance. Besides, hypotheses that explain the origin and biogeographical distribution of sciaenid fishes are controversial. In this study, the complete mitochondrial genome sequences of seven representative sciaenid species were determined and a well-resolved tree was recovered. This new timescale demonstrated that the sciaenid originated during the late Jurassic to early Cretaceous Period. The estimated origin time of sciaenid fish is 208 Mya, and the origin of Old World sciaenid is estimated at 126 Mya. Reconstruction of ancestral distributions indicated a plesiomorphic distribution and center of origin in the New World, with at least one lineage subsequently dispersed to the Old World. Moreover, we conclude that the common ancestors of Old World sciaenid fishes were derived from species of New World.

  1. Upper and lower mesophotic coral reef fish communities evaluated by underwater visual censuses in two Caribbean locations

    Science.gov (United States)

    Pinheiro, H. T.; Goodbody-Gringley, G.; Jessup, M. E.; Shepherd, B.; Chequer, A. D.; Rocha, L. A.

    2016-03-01

    Despite more than 60 yr of coral reef research using scuba diving, mesophotic coral ecosystems (MCEs) between 30 and 150 m depth remain largely unknown. This study represents the first underwater visual census of reef fish communities in the Greater Caribbean on MCEs at depths up to 80 m in Bermuda and 130 m in Curaçao. Sampling was performed using mixed-gas closed-circuit rebreathers. Quantitative data on reef fish communities were obtained for four habitats: coral reefs (45-80 m), rhodolith beds (45-80 m), ledges (85-130 m) and walls (85-130 m). A total of 38 species were recorded in Bermuda and 66 in Curaçao. Mesophotic reef fish communities varied significantly between the two localities. MCEs in Bermuda had lower richness and abundance, but higher biomass than those in Curaçao. Richness, abundance and biomass increased with depth in Bermuda, but decreased in Curaçao. A high turnover of species was found among depth strata and between Bermuda and other Caribbean upper MCEs (45-80 m), indicating that depth was an important driver of community structure at all localities. However, local and evolutionary factors (habitat and endemism) are likely the main factors shaping communities in isolated locations such as Bermuda. High fishing pressure is evident in both localities, as total biomass of apex predators was generally low, and thus may be driving a "refugia" scenario in Bermuda, as the abundance and biomass of macro-carnivores increased with depth and distance from the coast.

  2. Evolution of Rotations in the Fish Creek Vallecito Basin, Western Salton Trough, CA

    Science.gov (United States)

    Housen, B. A.; Dorsey, R. J.; Janecke, S. U.; Axen, G. J.

    2006-12-01

    Rocks in the Western Salton Trough region record the history of slip on the transtensional West Salton detachment fault and initiation of younger strike-slip faults in this plate boundary zone. Spatial and temporal patterns of vertical axis rotations as determined by paleomagnetism can be used to provide valuable constraints on the structural-tectonic evolution of this area. Prior work includes the magnetostratigraphy of Plio-Pleistocene sedimentary rocks in the Fish Creek-Vallecito Basin (FCVB) (Opdyke et al., 1977; Johnson et al., 1983), who found that these rocks contain a complete record of geomagnetic field reversals spanning Pliocene-Pleistocene time. Johnson et al. (1983) also concluded that the FCVB had undergone 35° of CW rotation during the past 0.9 Ma. We resampled and reanalyzed their section, and sampled additional sedimentary and plutonic rocks in the Western Salton Trough in order to better document the history of vertical axis rotation recorded by these rocks. Results from 29 sites in the FCVB have well-defined magnetizations with two components. The first removed component in all samples is unblocked between 90 and 220 °C, and the second-removed components are unblocked between 300 and 590 °C. The second-removed components have either normal or reversed polarity. Sites from the Diablo Fm are predominantly reversed and have a mean of D = 204, I = -48.3, k = 37, α95 = 12.7°, N = 5. Sites from the middle of the section (Olla and Tapiado Fms) are predominantly normal and have a mean of D = 8.1, I = 48, k = 32, α95= 8.7°, N = 10. Sites from the upper portion of the section (Hueso Fm) have predominantly reversed polarity with means of D = 179.6, I = -43.4, k = 82, α95 = 10.2°, N = 4. Results from weakly-magnetized and deformed rocks of the La Posta pluton, on the south side of Whale Peak, have well-defined magnetizations with a group mean direction of D = 16.3, I = 37.3, k = 44, α95 = 7.4°, N = 10. The stratigraphic distribution of declination

  3. A reappraisal of the evolution of Asian snakehead fishes (Pisces, Channidae) using molecular data from multiple genes and fossil calibration.

    Science.gov (United States)

    Adamson, Eleanor A S; Hurwood, David A; Mather, Peter B

    2010-08-01

    Freshwater snakehead fishes (Channidae) provide an interesting target for phylogenetic analysis for the following reasons, their unusual biology, potential for cryptic diversity and availability of a good fossil record. Here, a multi-locus molecular phylogeny was constructed and calibrated using two fossil dates to estimate divergence times within the family. Sampling aimed to explore interspecific divergence of Channa species across Southeast Asia and intra-specific variation where species possessed natural geographical ranges that were extensive. Results contradict divergence times estimated previously independently from single locus mitochondrial data or the fossil record and suggest that after divergence from African taxa 40-50 Ma, evolution of Asian snakeheads has been heavily influenced by multiple broad scale dispersal events across India and Southeast Asia. A similar pattern of divergence within multiple clades suggests that west-east dispersal was limited for many taxa during the Miocene. Deep intra-specific divergence was inferred for C. striata, indicating that long historical periods of isolation ( approximately 8Ma) have not resulted in the evolution of reproductive isolation within this species. Results support suggestions that C. marulia like fishes in northern Cambodia may constitute an undescribed species, and that Indian C. diplogramma warrants taxonomic recognition as being distinct from Southeast Asian C. micropeltes, with the two taxa last sharing a common ancestor in the mid- to late-Miocene.

  4. Evolution study of contamination Russian Baltic fish by PCDD/F and WHO-PCB

    Energy Technology Data Exchange (ETDEWEB)

    Shelepchikov, A.; Brodsky, E. [Inst. of Ecology and Evolution of Russian Academy of Sciences (IPEE RAS) (Russian Federation); Shenderyuk, V.; Baholdina, L. [Atlantic Research Inst. of Fish Industry and Oceanography, (AtlantNIRO) (Russian Federation)

    2004-09-15

    Baltic Sea is well known as the most polluted sea in the world, but its fish products have a significant role in diet of Baltic countries habitants. In Dioxin 2003 meeting we have present first results of analysis of Baltic fishes caught by Russian fisherman for market. The results confirmed a rather high level of pollution in the Baltic seafood by PCDD/Fs and have shown necessity of the further researches. Although PCDD/Fs profile in fisher's body is not consist unsteady and was formed under affection of various factors, it was obvious that essential path comes with PCB; also previously were found that WHO-TEQ{sub PCB} in seafood could exceed WHO-TEQ{sub PCDD/F} level. In given works we present results of the analysis of two freshwater species of fishes and updating research of former analyzed kinds, included of WHO-PCBs determination.

  5. Genetic mating systems and reproductive natural histories of fishes: lessons for ecology and evolution.

    Science.gov (United States)

    Avise, John C; Jones, Adam G; Walker, DeEtte; DeWoody, J Andrew

    2002-01-01

    Fish species have diverse breeding behaviors that make them valuable for testing theories on genetic mating systems and reproductive tactics. Here we review genetic appraisals of paternity and maternity in wild fish populations. Behavioral phenomena quantified by genetic markers in various species include patterns of multiple mating by both sexes; frequent cuckoldry by males and rare cuckoldry by females in nest-tending species; additional routes to surrogate parentage via nest piracy and egg-thievery; egg mimicry by nest-tending males; brood parasitism by helper males in cooperative breeders; clutch mixing in oral brooders; kinship in schooling fry of broadcast spawners; sperm storage by dams in female-pregnant species; and sex-role reversal, polyandry, and strong sexual selection on females in some male-pregnant species. Additional phenomena addressed by genetic parentage analyses in fishes include clustered mutations, filial cannibalism, and local population size. All results are discussed in the context of relevant behavioral and evolutionary theory.

  6. Diel variation of fish community in sandy beaches of southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Luiz Ricardo Gaelzer

    2008-03-01

    Full Text Available Fish living in coastal waters present behavior patterns ruled by environmental light levels. Diel variations in fish community structure were investigated at Arraial do Cabo surf zone (22º58'S, 42º01'W. From September/2001 to August/2002 monthly sampling consisted of 12 hauls of a beach seine during the day and at night at Praia dos Anjos, Praia Grande and Prainha beaches. Different temporal distribution patterns of the ichthyc community were recorded. At Praia dos Anjos, total richness was higher at night while the average number of species, CPUE, Margalef's richness and Shannon diversity were generally higher during the day. We believe that this pattern was caused by the displacement of some species such as Harengula clupeola,Trachinotus carolinus and Umbrina coroides at night to deeper areas searching for food or for predator avoidance. At Praia Grande and Prainha the average number of species, CPUE, richness and diversity indexes were generally higher at night with the dominant species H. clupeola, Pomatomus saltatrix and Sardinella brasiliensis. It is suggested that the main factor to diel variation is the protection against predators due to darkness, making visualization of the prey difficult, besides the presence of seasonal macroalgae beds at Prainha, which might function as a food area for piscivorous fishes due to the proximity of larger individuals in shallower water especially at night.Peixes que vivem em águas costeiras marinhas exibem modelos de comportamento que são regulados pelos níveis de luz do ambiente. A variação nictemeral na estrutura da comunidade de peixes de zona de arrebentação foi investigada na região de Arraial do Cabo (22º58'S, 42º01'W. Desetembro/2001 a agosto/2002 foram realizadas coletas mensais, sendo efetuadas 12 arrastos utilizando cerco de praia nos períodos diurnos e noturnos na Praia dos Anjos, Praia Grande e Prainha. Diferentes padrões de distribuição da comunidade ictíca foram

  7. Community capacity as an "inside job": evolution of perceived ownership within a university-aboriginal community partnership.

    Science.gov (United States)

    Cargo, Margaret D; Delormier, Treena; Lévesque, Lucie; McComber, Alex M; Macaulay, Ann C

    2011-01-01

    PURPOSE. To assess the evolution of perceived ownership of a university-Aboriginal community partnership across three project stages. DESIGN. Survey administration to project partners during project formalization (1996-T1), mobilization (1999-T2), and maintenance (2004-T3). SETTING. Aboriginal community of Kahnawake, outside Montreal, Quebec, Canada. PARTICIPANTS. Partners involved in influencing decision making in the Kahnawake Schools Diabetes Prevention Project (KSDPP). MEASURE AND ANALYSIS . A measure of perceived primary ownership subjected to linear trend analysis. RESULTS. KSDPP staff were perceived as primary owner at T1 and shared ownership with Community Advisory Board (CAB) members at T2 and T3. Trend tests indicated greater perceived ownership between T1 and T3 for CAB (χ(2)(1)  =  12.3, p community driven from the beginning. It was not dependent on an external academic change agent to activate the community and develop the community's capacity to plan and implement a solution. It still took several years for the grassroots CAB to take responsibility from KSDPP staff, thus indicating the need for sustained funding to build grassroots community capacity.

  8. Fish genomes provide novel insights into the evolution of vertebrate secretin receptors and their ligand.

    Science.gov (United States)

    Cardoso, João C R; Félix, Rute C; Trindade, Marlene; Power, Deborah M

    2014-12-01

    The secretin receptor (SCTR) is a member of Class 2 subfamily B1 GPCRs and part of the PAC1/VPAC receptor subfamily. This receptor has long been known in mammals but has only recently been identified in other vertebrates including teleosts, from which it was previously considered to be absent. The ligand for SCTR in mammals is secretin (SCT), an important gastrointestinal peptide, which in teleosts has not yet been isolated, or the gene identified. This study revises the evolutionary model previously proposed for the secretin-GPCRs in metazoan by analysing in detail the fishes, the most successful of the extant vertebrates. All the Actinopterygii genomes analysed and the Chondrichthyes and Sarcopterygii fish possess a SCTR gene that shares conserved sequence, structure and synteny with the tetrapod homologue. Phylogenetic clustering and gene environment comparisons revealed that fish and tetrapod SCTR shared a common origin and diverged early from the PAC1/VPAC subfamily group. In teleosts SCTR duplicated as a result of the fish specific whole genome duplication but in all the teleost genomes analysed, with the exception of tilapia (Oreochromis niloticus), one of the duplicates was lost. The function of SCTR in teleosts is unknown but quantitative PCR revealed that in both sea bass (Dicentrarchus labrax) and tilapia (Oreochromis mossambicus) transcript abundance is high in the gastrointestinal tract suggesting it may intervene in similar processes to those in mammals. In contrast, no gene encoding the ligand SCT was identified in the ray-finned fishes (Actinopterygii) although it was present in the coelacanth (lobe finned fish, Sarcopterygii) and in the elephant shark (holocephalian). The genes in linkage with SCT in tetrapods and coelacanth were also identified in ray-finned fishes supporting the idea that it was lost from their genome. At present SCTR remains an orphan receptor in ray-finned fishes and it will be of interest in the future to establish why SCT was

  9. Insights into the evolution of proglucagon-derived peptides and receptors in fish and amphibians.

    Science.gov (United States)

    Ng, Stephanie Y L; Lee, Leo T O; Chow, Billy K C

    2010-07-01

    Glucagon and the glucagon-like peptides (GLP-1 and GLP-2) share a common evolutionary origin and are triplication products of an ancestral glucagon exon. In mammals, a standard scenario is found where only a single proglucagon-derived peptide set exists. However, fish and amphibians have either multiple proglucagon genes or exons that are likely resultant of duplication events. Through phylogenetic analysis and examination of their respective functions, the proglucagon ligand-receptor pairs are believed to have evolved independently before acquiring specificity for one another. This review will provide a comprehensive overview of current knowledge of proglucagon-derived peptides and receptors, with particular focus on fish and amphibian species.

  10. Chromosome evolution in Solanum traced by cross-species BAC-FISH

    NARCIS (Netherlands)

    Szinay, D.; Wijnker, E.; Berg, van den R.G.; Visser, R.G.F.; Jong, de J.H.S.G.M.; Bai, Y.

    2012-01-01

    Chromosomal rearrangements are relatively rare evolutionary events and can be used as markers to study karyotype evolution. This research aims to use such rearrangements to study chromosome evolution in Solanum. Chromosomal rearrangements between Solanum crops and several related wild species were

  11. Socio-demographic factors and fish eating trends in eastern community, Sri Lanka

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    Chandravathany Devadawson

    2015-10-01

    Full Text Available Fish are considered as a unique source of protein and long chain polyunsaturated fatty acids (PUFA. In Sri Lankan population, fish consumption habits and attitudes are determined by the availability of fish and socio-demography of fish consumers. An extensive survey was carried out among fish consumers (N=1777 in stratified random manner. Among the total studied respondents, 73.3% of the respondents had eaten all type of fish while10% had only sea fishes, 19.5 % brackish water and rest 4.2% had eaten fresh water fishes. Furthermore, of total 19.1 % people had consumed fish daily while 80.9% people had consumed fish weekly or monthly. Results of the study concluded that 64 % studied respondents had fish at both lunch and dinner time while 25% had three times and rest11% consumed only at lunch. The choice of fish in market were determined by various factors such as taste (5.7%, smell (8.5%, appearance (51.5%, nutrition (2.1%, availability (12.7%, prize (37.3%, health (14%, quality (53%, shape (26.7% and considered all (24.2%. However, consumers were drawn their attention more than one factors in selecting fish from market. The results explained that quality of fish considered mostly in selection of fish with factors like prices and availability of fish. Among the studied respondents, the quantity of fish consumption varied with age such as 37.8% respondents which were belongs to the 36- 45 age group had 30-40g, while27.5 % were between ages of 46-55 had 41-50g daily and frequency of consumption was not independent of age (P<0.001. Of the total respondents, the trends of fish consumption for health purpose were varied and 37% respondents consume it to cure from heart diseases, while the 23% had fish to release pressure stroke (15%, eyesight (13% and during pregnancy (7%.

  12. Effects of Temperature, Salinity and Fish in Structuring the Macroinvertebrate Community in Shallow Lakes: Implications for Effects of Climate Change

    Science.gov (United States)

    Brucet, Sandra; Boix, Dani; Nathansen, Louise W.; Quintana, Xavier D.; Jensen, Elisabeth; Balayla, David; Meerhoff, Mariana; Jeppesen, Erik

    2012-01-01

    Climate warming may lead to changes in the trophic structure and diversity of shallow lakes as a combined effect of increased temperature and salinity and likely increased strength of trophic interactions. We investigated the potential effects of temperature, salinity and fish on the plant-associated macroinvertebrate community by introducing artificial plants in eight comparable shallow brackish lakes located in two climatic regions of contrasting temperature: cold-temperate and Mediterranean. In both regions, lakes covered a salinity gradient from freshwater to oligohaline waters. We undertook day and night-time sampling of macroinvertebrates associated with the artificial plants and fish and free-swimming macroinvertebrate predators within artificial plants and in pelagic areas. Our results showed marked differences in the trophic structure between cold and warm shallow lakes. Plant-associated macroinvertebrates and free-swimming macroinvertebrate predators were more abundant and the communities richer in species in the cold compared to the warm climate, most probably as a result of differences in fish predation pressure. Submerged plants in warm brackish lakes did not seem to counteract the effect of fish predation on macroinvertebrates to the same extent as in temperate freshwater lakes, since small fish were abundant and tended to aggregate within the macrophytes. The richness and abundance of most plant-associated macroinvertebrate taxa decreased with salinity. Despite the lower densities of plant-associated macroinvertebrates in the Mediterranean lakes, periphyton biomass was lower than in cold temperate systems, a fact that was mainly attributed to grazing and disturbance by fish. Our results suggest that, if the current process of warming entails higher chances of shallow lakes becoming warmer and more saline, climatic change may result in a decrease in macroinvertebrate species richness and abundance in shallow lakes. PMID:22393354

  13. Fish community structure in freshwater karstic water bodies of the Sian Ka'an Reserve in the Yucatan peninsula, Mexico

    Science.gov (United States)

    Zambrano, L.; Vazquez-Dominguez, E.; Garcia-Bedoya, D.; Loftus, W.F.; Trexler, J.C.

    2006-01-01

    We evaluated the relationship between limnetic characteristics and fish community structure (based on species richness, abundance and individual size) in contrasting but interconnected inland aquatic habitats of freshwater karstic wetlands in the Yucatan peninsula, Mexico. In the western hemisphere, freshwater karstic wetlands are found in south-eastern Mexico, northern Belize, western Cuba, Andros Island, Bahamas and the Everglades of southern Florida. Only in the Everglades have fish communities been well described. Karstic wetlands are typically oligotrophic because calcium carbonate binds phosphorus, making it relatively unavailable for plants. Fourteen permanent and seasonally flooded water bodies were sampled in both wet and dry seasons in Sian Ka'an Biosphere Reserve, in the Mexican state of Quintana Roo. Water systems were divided by morphology in four groups: cenotes with vegetation (CWV), cenotes without vegetation (CNV), wetlands (WTL), and temporal cenotes (TPC). Discriminant analysis based on physical characteristics such as turbidity, temperature, depth and oxygen confirmed that these habitats differed in characteristics known to influence fish communities. A sample-based rarefaction test showed that species richness was significantly different between water systems groups, showing that WTL and CWV had higher richness values than CNV and TPC. The most abundant fish families, Poeciliidae, Cichlidae and Characidae, differed significantly in average size among habitats and seasons. Seasonal and inter-annual variation, reflecting temporal variation in rainfall, strongly influenced the environmental differences between shallow and deep habitats, which could be linked to fish size and life cycles. Five new records of species were found for the reserve, and one new record for Quintana Roo state. ?? 2006 by Verlag Dr. Friedrich Pfeil.

  14. Amphidromy links a newly documented fish community of continental Australian streams, to oceanic islands of the west Pacific.

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    Paul A Thuesen

    Full Text Available BACKGROUND: Indo-Pacific high island streams experience extreme hydrological variation, and are characterised by freshwater fish species with an amphidromous life history. Amphidromy is a likely adaptation for colonisation of island streams following stochastic events that lead to local extirpation. In the Wet Tropics of north-eastern Australia, steep coastal mountain streams share similar physical characteristics to island systems. These streams are poorly surveyed, but may provide suitable habitat for amphidromous species. However, due to their ephemeral nature, common non-diadromous freshwater species of continental Australia are unlikely to persist. Consequently, we hypothesise that coastal Wet Tropics streams are faunally more similar, to distant Pacific island communities, than to nearby faunas of large continental rivers. METHODS/PRINCIPAL FINDINGS: Surveys of coastal Wet Tropics streams recorded 26 species, 10 of which are first records for Australia, with three species undescribed. This fish community is unique in an Australian context in that it contains mostly amphidromous species, including sicydiine gobies of the genera Sicyopterus, Sicyopus, Smilosicyopus and Stiphodon. Species presence/absence data of coastal Wet Tropics streams were compared to both Wet Tropics river networks and Pacific island faunas. ANOSIM indicated the fish fauna of north-eastern Australian coastal streams were more similar to distant Pacific islands (R = 0.76, than to nearby continental rivers (R = 0.98. MAIN CONCLUSIONS/SIGNIFICANCE: Coastal Wet Tropics streams are faunally more similar to distant Pacific islands (79% of species shared, than to nearby continental fauna due to two factors. First, coastal Wet Tropics streams lack many non-diadromous freshwater fish which are common in nearby large rivers. Second, many amphidromous species found in coastal Wet Tropics streams and Indo-Pacific islands remain absent from large rivers of the Wet Tropics

  15. Performance of biological phosphorus removal and characteristics of microbial community in the oxic-settling-anaerobic process by FISH analysis

    Institute of Scientific and Technical Information of China (English)

    Jian-fang WANG; Qing-liang ZHAO; Wen-biao JIN; Shi-jie YOU; Jin-na ZHANG

    2008-01-01

    Performance of biological phosphorus removal in the oxic-settling-anaerobic (OSA) process was investigated. Cell staining and fluorescent in situ hybridization (FISH) were used to analyze characteristics and microbial community of sludge.Experimental results showed that phosphorus removal efficiency was near 60% and the amount of biological phosphorus accumulation in aerobic sludge of the OSA system was up to 26.9 mg/g. Biological phosphorus removal efficiency was partially inhibited by carbon sources in the continuous OSA system. Contrasted to the OSA system, biological phosphorus removal efficiency was enhanced by 14% and the average total phosphorus (TP) contents of aerobic sludge were increased by 0.36 mg/g when sufficient carbon sources were supplied in batch experiments. Staining methods indicated that about 35% of microorganisms had typical characteristics of phosphorus accumulating organisms (PAOs). FISH analysis demonstrated that PAOMIX-binding bacteria were predominant microbial communities in the OSA system, which accounted for around 28% of total bacteria.

  16. Impact of arachidonic acid enrichment of live rotifer prey on bacterial communities in rotifer and larval fish cultures.

    Science.gov (United States)

    Seychelles, Laurent H; Doiron, Kim; Audet, Céline; Tremblay, Réjean; Pernet, Fabrice; Lemarchand, Karine

    2013-03-01

    Rotifers (Brachionus plicatilis), commonly used at first feeding in commercial fish hatcheries, carry a large bacteria load. Because they are relatively poor in essential fatty acids, it is common practice to enrich them with fatty acids, including arachidonic acid (AA). This study aims to determine whether prey enrichment with AA may act as a prebiotic and modify the microbial community composition either in AA-enriched rotifer cultures or in larval-rearing water using winter flounder (Pseudopleuronectes americanus) as a larval fish model. AA enrichment modified the bacterial community composition in both the rotifer culture tanks and the larval-rearing tanks. We observed an increase in the number of cultivable bacteria on TCBS (thiosulfate-citrate-bile salts-sucrose) agar, used as a proxy for the abundance of Vibrio sp. The results suggest that AA may also play an indirect role in larval health.

  17. Inferring Diversity and Evolution in Fish by Means of Integrative Molecular Cytogenetics.

    Science.gov (United States)

    Artoni, Roberto Ferreira; Castro, Jonathan Pena; Jacobina, Uedson Pereira; Lima-Filho, Paulo Augusto; da Costa, Gideão Wagner Werneck Félix; Molina, Wagner Franco

    2015-01-01

    Fish constitute a paraphyletic and profusely diversified group that has historically puzzled ichthyologists. Hard efforts are necessary to better understand this group, due to its extensive diversity. New species are often identified and it leads to questions about their phylogenetic aspects. Cytogenetics is becoming an important biodiversity-detection tool also used to measure biodiversity evolutionary aspects. Molecular cytogenetics by fluorescence in situ hybridization (FISH) allowed integrating quantitative and qualitative data from DNA sequences and their physical location in chromosomes and genomes. Although there is no intention on presenting a broader review, the current study presents some evidences on the need of integrating molecular cytogenetic data to other evolutionary biology tools to more precisely infer cryptic species detection, population structuring in marine environments, intra- and interspecific karyoevolutionary aspects of freshwater groups, evolutionary dynamics of marine fish chromosomes, and the origin and differentiation of sexual and B chromosomes. The new cytogenetic field, called cytogenomics, is spreading due to its capacity to give resolute answers to countless questions that cannot be answered by traditional methodologies. Indeed, the association between chromosomal markers and DNA sequencing as well as between biological diversity analysis methodologies and phylogenetics triggers the will to search for answers about fish evolutionary, taxonomic, and structural features.

  18. Evolution of cadmium effects in the testis and sperm of the tropical fish Gymnotus carapo.

    Science.gov (United States)

    Vergilio, C S; Moreira, R V; Carvalho, C E V; Melo, E J T

    2015-04-01

    The present study investigated the testis and sperm morphology of the tropical fish Gymnotus carapo after exposure to increasing CdCl2 concentrations (5-40 μM) for 24 and 96 h. The treatments induced Cd accumulation in the testis and a decrease in the gonadosomatic index from a 10 μM. Cd induced alterations in testis since 24h; however the extension and severity of damages increased after 96 h in all tested concentrations. Marked variations in the cysts size, proliferation of the interstitial tissue, infiltration of inflammatory cells, necrosis, reduction of germ cells and sperm aggregation was observed in 96 h treated fishes. In this time, there was a complete absence of germ cells in the testis of fish treated with 40 μM. The ultrastructural analysis allowed for the visualization of the initial damages over germ cells, such as the presence of vacuoles in the cytoplasm of spermatogonia, spermatocytes, and spermatids. Exposed fish (20 μM for 24 and 96 h) had alterations in sperm number and morphology. These results are important for establishing a direct correlation between the Cd accumulation and incidence of damages and can help characterize the mechanism of Cd-induced pathogenesis in the male reproductive system.

  19. Inferring Diversity and Evolution in Fish by Means of Integrative Molecular Cytogenetics

    Directory of Open Access Journals (Sweden)

    Roberto Ferreira Artoni

    2015-01-01

    Full Text Available Fish constitute a paraphyletic and profusely diversified group that has historically puzzled ichthyologists. Hard efforts are necessary to better understand this group, due to its extensive diversity. New species are often identified and it leads to questions about their phylogenetic aspects. Cytogenetics is becoming an important biodiversity-detection tool also used to measure biodiversity evolutionary aspects. Molecular cytogenetics by fluorescence in situ hybridization (FISH allowed integrating quantitative and qualitative data from DNA sequences and their physical location in chromosomes and genomes. Although there is no intention on presenting a broader review, the current study presents some evidences on the need of integrating molecular cytogenetic data to other evolutionary biology tools to more precisely infer cryptic species detection, population structuring in marine environments, intra- and interspecific karyoevolutionary aspects of freshwater groups, evolutionary dynamics of marine fish chromosomes, and the origin and differentiation of sexual and B chromosomes. The new cytogenetic field, called cytogenomics, is spreading due to its capacity to give resolute answers to countless questions that cannot be answered by traditional methodologies. Indeed, the association between chromosomal markers and DNA sequencing as well as between biological diversity analysis methodologies and phylogenetics triggers the will to search for answers about fish evolutionary, taxonomic, and structural features.

  20. Understanding the Spatio-Temporal Response of Coral Reef Fish Communities to Natural Disturbances: Insights from Beta-Diversity Decomposition.

    Science.gov (United States)

    Lamy, Thomas; Legendre, Pierre; Chancerelle, Yannick; Siu, Gilles; Claudet, Joachim

    2015-01-01

    Understanding how communities respond to natural disturbances is fundamental to assess the mechanisms of ecosystem resistance and resilience. However, ecosystem responses to natural disturbances are rarely monitored both through space and time, while the factors promoting ecosystem stability act at various temporal and spatial scales. Hence, assessing both the spatial and temporal variations in species composition is important to comprehensively explore the effects of natural disturbances. Here, we suggest a framework to better scrutinize the mechanisms underlying community responses to disturbances through both time and space. Our analytical approach is based on beta diversity decomposition into two components, replacement and biomass difference. We illustrate this approach using a 9-year monitoring of coral reef fish communities off Moorea Island (French Polynesia), which encompassed two severe natural disturbances: a crown-of-thorns starfish outbreak and a hurricane. These disturbances triggered a fast logistic decline in coral cover, which suffered a 90% decrease on all reefs. However, we found that the coral reef fish composition remained largely stable through time and space whereas compensatory changes in biomass among species were responsible for most of the temporal fluctuations, as outlined by the overall high contribution of the replacement component to total beta diversity. This suggests that, despite the severity of the two disturbances, fish communities exhibited high resistance and the ability to reorganize their compositions to maintain the same level of total community biomass as before the disturbances. We further investigated the spatial congruence of this pattern and showed that temporal dynamics involved different species across sites; yet, herbivores controlling the proliferation of algae that compete with coral communities were consistently favored. These results suggest that compensatory changes in biomass among species and spatial

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

    Science.gov (United States)

    George-Nascimento, Mario; Oliva, Marcelo

    2015-01-01

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

  2. Trophic redundancy among fishes in an East African nearshore seagrass community inferred from stable-isotope analysis.

    Science.gov (United States)

    Matich, P; Kiszka, J J; Gastrich, K R; Heithaus, M R

    2017-08-01

    Stable-isotope analysis supplemented with stomach contents data from published sources was used to quantify the trophic niches, trophic niche overlaps and potential trophic redundancy for the most commonly caught fish species from an East African nearshore seagrass community. This assessment is an important first step in quantifying food-web structure in a region subject to intense fishing activities. Nearshore food webs were driven by at least two isotopically distinct trophic pathways, algal and seagrass, with a greater proportion of the sampled species feeding within the seagrass food web (57%) compared with the algal food web (33%). There was considerable isotopic niche overlap among species (92% of species overlapped with at least one other species). Narrow isotopic niche widths of most (83%) species sampled, low isotopic similarity (only 23% of species exhibited no differences in δ(13) C and δ(15) N) and low predicted trophic redundancy among fishes most commonly caught by fishermen (15%), however, suggest that adjustments to resource management concerning harvesting and gear selectivity may be needed for the persistence of artisanal fishing in northern Tanzania. More detailed trophic studies paired with information on spatio-temporal variation in fish abundance, especially for heavily targeted species, will assist in the development and implementation of management strategies to maintain coastal food-web integrity. © 2017 The Fisheries Society of the British Isles.

  3. From Static Content to Dynamic Communities: The Evolution of Networked Educational Resources.

    Science.gov (United States)

    Jacobs, Neil; Huxley, Lesly

    2002-01-01

    Discusses Web-based educational resources in the United Kingdom, focusing on current challenges of linking content with community and static information with dynamic news. Describes the evolution of three social sciences resources and examines sustainability, the need for collaboration, and data protection and privacy concerns. (Author/LRW)

  4. HIV infection in fishing communities of Lake Victoria Basin of Uganda--a cross-sectional sero-behavioral survey.

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    Alex Opio

    Full Text Available BACKGROUND: Uganda's first AIDS case was reported in a fishing village. Thereafter, due to varying risk factors, the epidemic spread heterogeneously to all regions, with some populations more affected. Given the recent rising trends in HIV infection in Uganda, it is crucial to know the risk factors in different populations. The aim of this study was to determine the prevalence and risk factors of HIV infection among fishing communities. METHODOLOGY: A cross-sectional survey of 46 fishing communities was conducted in 2010. Following written consent, 911 randomly selected respondents age 15-59 years were interviewed and gave blood for HIV testing. HIV testing was conducted in the field and central laboratory according to national algorithm. Survey protocol was approved by the Science and Ethics Committee of Uganda Virus Research Institute, and cleared by Uganda National Council for Science and Technology. Data was captured by EPIINFO and statistical analysis done in SPSS. FINDINGS: Overall HIV prevalence was 22%; there was no difference by sex (x (2 test, p>0.05. Association with HIV infection was determined by x (2 test, p<0.5. Never married respondents had lower HIV prevalence (6.2% than the ever married (24.1%. HIV prevalence was lower in younger respondents, age 15-24 years (10.8% than in age group 25 years and above (26.1%. Muslims had lower HIV prevalence (14.4% than Christians (25.2%. HIV prevalence was higher among respondents reporting 3 or more lifetime sexual partners (25.3% than in those reporting less numbers (10.8%. HIV prevalence was higher among uncircumcised men (27% than in circumcised men (11%. Multivariate analysis identified 4 risk factors for HIV infection; age, religion, ever condom use and number of lifetime sexual partners. CONCLUSIONS: HIV prevalence in the surveyed communities was three times higher than of general population. This underscores the need for tailor made HIV combination prevention interventions targeting

  5. The Effects of Run-of-River Hydroelectric Power Schemes on Fish Community Composition in Temperate Streams and Rivers.

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    Gary S Bilotta

    Full Text Available The potential environmental impacts of large-scale storage hydroelectric power (HEP schemes have been well-documented in the literature. In Europe, awareness of these potential impacts and limited opportunities for politically-acceptable medium- to large-scale schemes, have caused attention to focus on smaller-scale HEP schemes, particularly run-of-river (ROR schemes, to contribute to meeting renewable energy targets. Run-of-river HEP schemes are often presumed to be less environmentally damaging than large-scale storage HEP schemes. However, there is currently a lack of peer-reviewed studies on their physical and ecological impact. The aim of this article was to investigate the effects of ROR HEP schemes on communities of fish in temperate streams and rivers, using a Before-After, Control-Impact (BACI study design. The study makes use of routine environmental surveillance data collected as part of long-term national and international monitoring programmes at 23 systematically-selected ROR HEP schemes and 23 systematically-selected paired control sites. Six area-normalised metrics of fish community composition were analysed using a linear mixed effects model (number of species, number of fish, number of Atlantic salmon-Salmo salar, number of >1 year old Atlantic salmon, number of brown trout-Salmo trutta, and number of >1 year old brown trout. The analyses showed that there was a statistically significant effect (p<0.05 of ROR HEP construction and operation on the number of species. However, no statistically significant effects were detected on the other five metrics of community composition. The implications of these findings are discussed in this article and recommendations are made for best-practice study design for future fish community impact studies.

  6. Patterns of variation in parasite component communities and infracommunities of a littoral fish species from the northern coast of Chile.

    Science.gov (United States)

    Henríquez, Vania; González, M Teresa

    2014-03-01

    The structure and similarity of the parasite communities of fish can be evaluated at the component community (CC) and infracommunity (IC) levels. Both hierarchical levels have been used to assess parasite variations in fish at large (biogeographic) scales. However, studies evaluating the consistency between these two hierarchical levels at smaller geographical scales are scarce. In this study, the parasite assemblages of 124 Paralabrax humeralis collected by local fishermen by spear fishing at four sites (El Fierro, EF; P. Angamos, PA; Santa María, ISM; San Jorge, BSJ) in northern Chile were compared to assess the variability (or similarity) of their CCs and ICs at a limited geographical scale using multivariate analysis. At the IC level, discriminant analyses showed that P. humeralis parasite communities varied significantly among sites; 70% of ectoparasite ICs were correctly assigned to each site, but only 55% of helminth parasite ICs were correctly classified. At the CC level, the composition of parasite communities as assessed by correspondence analyses varied significantly between sites. Tagia sp., Neobenedenia sp. and Philometra sp. were associated with BSJ, ISM and PA, respectively; Corynosoma sp. and most digeneans were associated with both ISM and EF. Analysis of similarities (ANOSIM) showed significant variations in the degree of similarity between P. humeralis CCs from different sites, but not between ICs. Variations between CCs from different sites reflect fish population processes (e.g., population age, reproductive segregation) and the particular conditions of their respective habitats, whereas ICs reflect individual host movements. This study demonstrated that, when examined at a limited geographical scale, IC is better than CC at capturing the local pool of parasite assemblages when host populations are spatially segregated. Therefore, in this study, it is demonstrated that at a small geographic scale, CC variations are not reflected by IC, when

  7. Resilience strategies in the face of short- and long-term change: out-migration and fisheries regulation in Alaskan fishing communities

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    Amber Himes-Cornell

    2015-06-01

    Full Text Available Historically, communities persisted in remote, isolated areas of Alaska in large part because of the abundance of marine and terrestrial resources, as well as the ability of local people to opportunistically access those resources as they became available. Species switching and the ability to shift effort away from fisheries during poor years allowed local residents to diversify their livelihoods in the face of uncertainties and ecological change. The advent of modern fisheries management, which views Alaskan fisheries as the property of all citizens of the United States, has fundamentally altered the relationship of place-based communities to fishery resources. Local access to fisheries has been particularly affected by the development of transferable fishing privileges, making it possible for fishing rights to leave place-based communities through the choices of individual community members to sell or to move away. When fishing communities in Alaska lose active fishing businesses, over time the loss of various types of community capital will follow, including human, social, cultural, technical, and financial capital. In some cases, communities are able to adapt or transform through diversification of their local economies. In other cases, no alternatives to a fishery-based economy are accessible. We have used resilience theory to explore drivers of change affecting Alaskan fishing communities. Emphasis was placed on two primary change drivers, the regulatory environment and rural out-migration, as well as their interconnections and their impacts on individuals, communities, and the larger social-ecological system. We summarized several government programs that have been implemented to support the continued participation of communities in Alaskan fisheries. In addition, we reviewed informal and private-sector efforts to generate resilience strategies that can facilitate new entry into fisheries or retain fishing businesses and fishing rights

  8. Horizontal and vertical dynamics of zooplankton and larval fish communities during mid-summer in Disko Bay, West Greenland

    DEFF Research Database (Denmark)

    Munk, Peter; Nielsen, Torkel Gissel; Hansen, Benni Winding

    2015-01-01

    Disko Bay is a highly productive inlet at the border between high- and low-arctic sectors of west Greenland. The physical/chemical conditions in the bay have changed during recent decades, specifically during an inflow event in 1996–1997 that led to increased deep-water temperatures. To further...... and vertical distribution patterns, community composition and plankton trophodynamics. Plankton abundance was enhanced near-coast and across the pycnocline, and communities differed between regions. Polar cod (Boreogadus saida) and the sandeel (Ammodytes sp.) were among the abundant fish larvae. Productivity...

  9. Use of Modern Family Planning Methods in Fishing Communities of Lake Victoria, Uganda.

    Directory of Open Access Journals (Sweden)

    Annet Nanvubya

    Full Text Available Fishing communities (FCs in Uganda have high HIV infection rates but poor access to health services including family planning (FP. Although FP is a cost-effective public health intervention, there is a paucity of data on knowledge and use of modern FP in FCs. This study determined knowledge and use of modern FP methods in FCs of Uganda.Data were accrued from a 12-month follow up of 1,688 HIV-uninfected individuals, 18-49 years from 8 FCs along Lake Victoria, between September 2011 and March 2013. Data on knowledge and use of modern FP were collected through a semi-structured questionnaire. Prevalence Risk Ratios with corresponding 95% CIs were used to determine factors associated with Modern FP knowledge and use.The mean age was 31.4 years, with nearly half (48.8% being females while more than half (58.6% had attained up to primary education level. Knowledge of modern FP was high, 87.5% (1477/1688; significantly higher among females [adj. PRR = 4.84 (95% CI; 3.08, 7.61], among older respondents (25-29 years [adj. PRR = 1.83 (95% CI; 1.12, 2.99] compared to younger ones (18-24 years and among those conducting business [adj. PRR = 2.42(95% CI; 1.02, 5.74] relative to those primarily in fishing. Just over a third (35.2%, 595/1688 reported use of at least one modern FP method. Use of modern FP methods was significantly higher among females [adj. PRR = 2.04 (95% CI; 1.56, 2.65, and among those reporting multiple sexual partnerships [adj. PRR = 2.12, 95% CI; 1.63, 2.76]. Nonuse of modern methods was mostly due to desire for more children (30.6%, fear of side effects (12.2% and partner refusal (5.2%.Despite their high knowledge of FP, FCs have low use of modern FP methods. Key barriers to use of modern FP methods were high fertility desires, fear of perceived side effects and partner refusal of methods.

  10. Post-duplication charge evolution of phosphoglucose isomerases in teleost fishes through weak selection on many amino acid sites

    Directory of Open Access Journals (Sweden)

    Sato Yukuto

    2007-10-01

    Full Text Available Abstract Background The partitioning of ancestral functions among duplicated genes by neutral evolution, or subfunctionalization, has been considered the primary process for the evolution of novel proteins (neofunctionalization. Nonetheless, how a subfunctionalized protein can evolve into a more adaptive protein is poorly understood, mainly due to the limitations of current analytical methods, which can detect only strong selection for amino acid substitutions involved in adaptive molecular evolution. In this study, we employed a comparative evolutionary approach to this question, focusing on differences in the structural properties of a protein, specifically the electric charge, encoded by fish-specific duplicated phosphoglucose isomerase (Pgi genes. Results Full-length cDNA cloning, RT-PCR based gene expression analyses, and comparative sequence analyses showed that after subfunctionalization with respect to the expression organ of duplicate Pgi genes, the net electric charge of the PGI-1 protein expressed mainly in internal tissues became more negative, and that of PGI-2 expressed mainly in muscular tissues became more positive. The difference in net protein charge was attributable not to specific amino acid sites but to the sum of various amino acid sites located on the surface of the PGI molecule. Conclusion This finding suggests that the surface charge evolution of PGI proteins was not driven by strong selection on individual amino acid sites leading to permanent fixation of a particular residue, but rather was driven by weak selection on a large number of amino acid sites and consequently by steady directional and/or purifying selection on the overall structural properties of the protein, which is derived from many modifiable sites. The mode of molecular evolution presented here may be relevant to various cases of adaptive modification in proteins, such as hydrophobic properties, molecular size, and electric charge.

  11. Effect of magnesium peroxide biostimulation of fish feed-loaded marine sediments on changes in the bacterial community.

    Science.gov (United States)

    Santander-De Leon, Sheila Mae S; Okunishi, Suguru; Kihira, Masaki; Nakano, Miyo; Nuñal, Sharon N; Hidaka, Masayasu; Yoshikawa, Takeshi; Maeda, Hiroto

    2013-01-01

    The effect of an oxygen-releasing compound (ORC) magnesium peroxide (MgO(2)) on the changes in the bacterial community in organically polluted sediment of aquaculture farms was tested in a microcosm experiment. The sediment, to which fish feed was added, was treated with 1% or 5% MgO(2). The addition of fish feed induced a highly reduced environment with low redox potential, high total sulfides, and abundance of sulfate-reducing bacteria (SRB) . Although the sediment remained highly reduced at 1% MgO(2), there was a significant reduction of total sulfides, increase of redox potential, and resultant reduction of SRB. The bacterial community clearly changed with the treatments according to denaturing gradient gel electrophoresis (DGGE) analysis of 16S ribosomal RNA gene (16S rDNA) . Aerobes disappeared in the fish feed-added sediment, and some SRB emerged in place of these aerobes. On the other hand, the SRB disappeared in the ORC-amended sediment due to its highly oxic condition. This study revealed the bacterial community in the sediments was affected mainly by the redox potential and resultant sulfides produced by SRB, but total organic carbon and nitrogen were not determinants of the microbial population.

  12. Parallel evolution of genes controlling mitonuclear balance in short‐lived annual fishes

    National Research Council Canada - National Science Library

    Sahm, Arne; Bens, Martin; Platzer, Matthias; Cellerino, Alessandro

    2017-01-01

    .... Here, we investigated the pattern of positive selection in annual (i.e., short‐lived) and nonannual (i.e., longer‐lived) African killifishes to identify a genomic substrate for evolution of annual life history...

  13. Perceptions of HIV and Safe Male Circumcision in High HIV Prevalence Fishing Communities on Lake Victoria, Uganda.

    Science.gov (United States)

    Nevin, Paul E; Pfeiffer, James; Kibira, Simon P S; Lubinga, Solomon J; Mukose, Aggrey; Babigumira, Joseph B

    2015-01-01

    In 2010, the Uganda Ministry of Health introduced its Safe Male Circumcision (SMC) strategy for HIV prevention with the goal of providing 4.2 million voluntary medical male circumcisions by 2015. Fishing communities, where HIV prevalence is approximately 3-5 times higher than the national average, have been identified as a key population needing targeted HIV prevention services by the National HIV Prevention Strategy. This study aimed to understand perceptions of HIV and identify potential barriers and facilitators to SMC in fishing communities along Lake Victoria. We conducted 8 focus group discussions, stratified by sex and age, with 67 purposefully sampled participants in 4 communities in Kalangala District, Uganda. There was universal knowledge of the availability of SMC services, but males reported high uptake in the community while females indicated that it is low. Improved hygiene, disease prevention, and improved sexual performance and desirability were reported facilitators. Barriers included a perceived increase in SMC recipients' physiological libido, post-surgical abstinence, lost income during convalescence, and lengthier recovery due to occupational hazards. Both males and females reported concerns about spousal fidelity during post-SMC abstinence. Reported misconceptions and community-held cultural beliefs include fear that foreskins are sold after their removal, the belief that a SMC recipient's first sexual partner after the procedure should not be his spouse, and the belief that vaginal fluids aid circumcision wound healing. Previous outreach efforts have effectively reached these remote communities, where availability and health benefits of SMC are widely understood. However, community-specific intervention strategies are needed to address the barriers identified in this study. We recommend the development of targeted counseling, outreach, and communication strategies to address barriers, misconceptions, and community-held beliefs. Interventions

  14. Perceptions of HIV and Safe Male Circumcision in High HIV Prevalence Fishing Communities on Lake Victoria, Uganda.

    Directory of Open Access Journals (Sweden)

    Paul E Nevin

    Full Text Available In 2010, the Uganda Ministry of Health introduced its Safe Male Circumcision (SMC strategy for HIV prevention with the goal of providing 4.2 million voluntary medical male circumcisions by 2015. Fishing communities, where HIV prevalence is approximately 3-5 times higher than the national average, have been identified as a key population needing targeted HIV prevention services by the National HIV Prevention Strategy. This study aimed to understand perceptions of HIV and identify potential barriers and facilitators to SMC in fishing communities along Lake Victoria.We conducted 8 focus group discussions, stratified by sex and age, with 67 purposefully sampled participants in 4 communities in Kalangala District, Uganda.There was universal knowledge of the availability of SMC services, but males reported high uptake in the community while females indicated that it is low. Improved hygiene, disease prevention, and improved sexual performance and desirability were reported facilitators. Barriers included a perceived increase in SMC recipients' physiological libido, post-surgical abstinence, lost income during convalescence, and lengthier recovery due to occupational hazards. Both males and females reported concerns about spousal fidelity during post-SMC abstinence. Reported misconceptions and community-held cultural beliefs include fear that foreskins are sold after their removal, the belief that a SMC recipient's first sexual partner after the procedure should not be his spouse, and the belief that vaginal fluids aid circumcision wound healing.Previous outreach efforts have effectively reached these remote communities, where availability and health benefits of SMC are widely understood. However, community-specific intervention strategies are needed to address the barriers identified in this study. We recommend the development of targeted counseling, outreach, and communication strategies to address barriers, misconceptions, and community-held beliefs

  15. International Barcode of Life: Evolution of a global research community.

    Science.gov (United States)

    Adamowicz, Sarah J

    2015-05-01

    The 6th International Barcode of Life Conference (Guelph, Canada, 18-21 August 2015), themed Barcodes to Biomes, showcases the latest developments in DNA barcoding research and its diverse applications. The meeting also provides a venue for a global research community to share ideas and to initiate collaborations. All plenary and contributed abstracts are being published as an open-access special issue of Genome. Here, I use a comparison with the 3rd Conference (Mexico City, 2009) to highlight 10 recent and emerging trends that are apparent among the contributed abstracts. One of the outstanding trends is the rising proportion of abstracts that focus upon multiple socio-economically important applications of DNA barcoding, including studies of agricultural pests, quarantine and invasive species, wildlife forensics, disease vectors, biomonitoring of ecosystem health, and marketplace surveys evaluating the authenticity of seafood products and medicinal plants. Other key movements include the use of barcoding and metabarcoding approaches for dietary analyses-and for studies of food webs spanning three or more trophic levels-as well as the spread of next-generation sequencing methods in multiple contexts. In combination with the rising taxonomic and geographic scope of many barcoding iniatives, these developments suggest that several important questions in biology are becoming tractable. "What is this specimen on an agricultural shipment?", "Who eats whom in this whole food web?", and even "How many species are there?" are questions that may be answered in time periods ranging from a few years to one or a few decades. The next phases of DNA barcoding may expand yet further into prediction of community shifts with climate change and improved management of biological resources.

  16. Patterns of trophic niche divergence between invasive and native fishes in wild communities are predictable from mesocosm studies.

    Science.gov (United States)

    Tran, Thi Nhat Quyen; Jackson, Michelle C; Sheath, Danny; Verreycken, Hugo; Britton, J Robert

    2015-07-01

    Ecological theory attempts to predict how impacts for native species arise from biological invasions. A fundamental question centres on the feeding interactions of invasive and native species: whether invasion will result in increased interspecific competition, which would result in negative consequences for the competing species, or trophic niche divergence, which would facilitate the invader's integration into the community and their coexistence with native species. Here, the feeding interactions of a highly invasive fish, topmouth gudgeon Pseudorasbora parva, with three native and functionally similar fishes were studied to determine whether patterns of either niche overlap or divergence detected in mesocosm experiments were apparent between the species at larger spatial scales. Using stable isotope analysis, their feeding relationships were assessed initially in the mesocosms (1000 L) and then in small ponds (600 m(2) ). In the mesocosms, a consistent pattern of trophic niche divergence was evident between the sympatric fishes, with niches shifting further apart in isotopic space than suggested in allopatry, revealing that sharing of food resources was limited. Sympatric P. parva also had a smaller niche than their allopatric populations. In eight small ponds where P. parva had coexisted for several years with at least one of the fish species used in the mesocosms, strong patterns of niche differentiation were also apparent, with P. parva always at a lower trophic position than the other fishes, as also occurred in the mesocosms. Where these fishes were sympatric within more complex fish communities in the large ponds, similar patterns were also apparent, with strong evidence of trophic niche differentiation. Aspects of the ecological impacts of P. parva invasion for native communities in larger ponds were consistent with those in the mesocosm experiments. Their invasion resulted in divergence in trophic niches, partly due to their reduced niche widths

  17. Integrating evolution into geographical ecology: a phylogenetic perspective on palm distributions and community composition across scales

    DEFF Research Database (Denmark)

    Eiserhardt, Wolf L.; Svenning, J.-C.; Kissling, W. Daniel

    species pool effects, those processes also affect local community composition and richness. In addition, evolution directly affects local communities directly via niche-based assembly. We studied these effects with palms (Arecaceae) as a model group, using a) a dataset including >340,000 palm individuals...... in 430 transects in the Western Amazon, b) a set of range maps for all American palms (550 spp.), and c) global country-level presence/ absence data of all (>2400) palm species. These data were analysed with novel phylogenetic community structure and turnover methods. Globally, the phylogenetic structure...... of palm assemblages reflects several biogeographic and evolutionary processes. In the Americas, both dispersal limitation and a phylogenetically conserved temperature niche have constrained the evolution of palm species ranges. Broad-scale processes also influenced the local phylogenetic structure...

  18. Evolution of microhabitat association and morphology in a diverse group of cryptobenthic coral reef fishes (Teleostei: Gobiidae: Eviota).

    Science.gov (United States)

    Tornabene, Luke; Ahmadia, Gabby N; Berumen, Michael L; Smith, Dave J; Jompa, Jamaluddin; Pezold, Frank

    2013-01-01

    Gobies (Teleostei: Gobiidae) are an extremely diverse and widely distributed group and are the second most species rich family of vertebrates. Ecological drivers are key to the evolutionary success of the Gobiidae. However, ecological and phylogenetic data are lacking for many diverse genera of gobies. Our study investigated the evolution of microhabitat association across the phylogeny of 18 species of dwarfgobies (genus Eviota), an abundant and diverse group of coral reef fishes. In addition, we also explore the evolution of pectoral fin-ray branching and sensory head pores to determine the relationship between morphological evolution and microhabitat shifts. Our results demonstrate that Eviota species switched multiple times from a facultative hard-coral association to inhabiting rubble or mixed sand/rubble habitat. We found no obvious relationship between microhabitat shifts and changes in pectoral fin-ray branching or reduction in sensory pores, with the latter character being highly homoplasious throughout the genus. The relative flexibility in coral-association in Eviota combined with the ability to move into non-coral habitats suggests a genetic capacity for ecological release in contrast to the strict obligate coral-dwelling relationship commonly observed in closely related coral gobies, thus promoting co-existence through fine scale niche partitioning. The variation in microhabitat association may facilitate opportunistic ecological speciation, and species persistence in the face of environmental change. This increased speciation opportunity, in concert with a high resilience to extinction, may explain the exceptionally high diversity seen in Eviota compared to related genera in the family.

  19. The Influence of Community Management Agreements on Household Economic Strategies : Cattle Grazing and Fishing Agreements on the Lower Amazon Floodplain

    Directory of Open Access Journals (Sweden)

    David G. McGrath

    2007-10-01

    Full Text Available While the organizational dynamics of collective management systems have received much attention, relatively little work has focused on how households adapt their economic strategies in response to collective management regulations that impose constraints on the range of options available to households. In this paper we investigate the evolving interaction between household management strategies and collective management regulations for one or both of two ecologically interdependent floodplain resources, lake fisheries and seasonally inundated grasslands. Smallholder management strategies involve varying combinations of three main activities each associated with one of three main floodplain habitats: annual cropping on river levees, cattle ranching on natural grasslands and fishing in lakes. These three activities play complementary roles in the household economy. Annual cropping is both subsistence and market oriented, with cash from crop sales often invested in purchase of cattle. Fishing, in addition to providing animal protein, generates income for household purchases while crops are growing. Cattle ranching is the main savings strategy for smalholders, providing funds for family emergencies and capital investments. Despite the fertility of soils and the higher productivity per hectare of fishing, cattle ranching has expanded steadily on the floodplain at the expense of farming and fishing. Over the last two decades, communities throughout the Amazon floodplain have developed and implemented collective agreements to regulate access to and use of local lake fisheries. Depending on the measures included, the impact of these agreements on household management strategies can range from negligible to highly significant, requiring major adjustments to compensate for reduced fishing income. Expansion of smallholder cattle ranching has taken advantage of unregulated access to community grasslands. Unregulated access to community grasslands has been a

  20. Biogeographic characterization of fish and benthic communities, St Croix, US Virgin Islands 2012-05-07 to 2012-05-18 (NODC Accession 0125237)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Reef fish populations are a conspicuous and essential component of USVI coral reef ecosystems. Yet despite their importance, striking population and community level...

  1. Baseline assessment of fish and benthic communities of the Flower Garden Banks (2010 - present) using remotely operated vehicle (ROV) survey methods: 2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The proposed work develop baseline information on fish and benthic communities within the Flower Garden Banks National Marine Sanctuary (FGBNMS). Surveys will...

  2. Baseline assessment of fish and benthic communities of the Flower Garden Banks (2010 - present) using remotely operated vehicle (ROV) survey methods: 2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The proposed work develop baseline information on fish and benthic communities within the Flower Garden Banks National Marine Sanctuary (FGBNMS). Surveys will employ...

  3. U. S. Fish & Wildlife Service Aquatic Invertebrate Community Study at Prime Hook NWR, Bombay Hook NWR, Long Island NWR Complex, Supawna Meadows NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The immediate goal of this study in the summer of 2000 was to collect baseline data on the aquatic invertebrate communities present in wetlands where mosquito...

  4. Studies of the Ecophysiology of Single Cells in Microbial Communities by (Quantitative) Microautoradiography and Fluorescence In Situ Hybridization (MAR-FISH)

    DEFF Research Database (Denmark)

    Nierychlo, Marta; Nielsen, Jeppe Lund; Nielsen, Per Halkjær

    2015-01-01

    Microautoradiography (MAR) in combination with fluorescence in situ hybridization (FISH) is a powerful method of obtaining information about the ecophysiology of probe-defined single cells in mixed microbial communities. The incorporation of radiolabelled substrates can be quantified by automated...

  5. The Evolution of Bourgeois, Parasitic, and Cooperative Reproductive Behaviors in Fishes

    OpenAIRE

    Taborsky, M.

    2017-01-01

    Among vertebrate classes, fishes exhibit by far the greatest variability in competitive and cooperative behaviors in male reproduction. Scramble competition between reproductive males is one possibility. Another possibility occurs when resources, mates, or locations can be monopolized, in which case males may invest in primary access to fertilizations by adopting a "bourgeois” strategy, or they may employ alternative mating tactics to evade the reproductive monopoly of other males. Adaptation...

  6. Distribution and community structure of fish in Obitsu-gawa River Estuary of inner Tokyo Bay, central Japan

    Directory of Open Access Journals (Sweden)

    Joeppette J. Hermosilla

    2012-09-01

    Full Text Available The distribution and community structure of fish in Obitsu-gawa River Estuary of inner TokyoBay, central Japan was studied from May to December 2005 and March to April 2006. A total of 19,006individuals, represented by 25 species and some unidentified species under family Clupeidae, Cyprinidae,Gobiidae, Hemiramphidae, Mugilidae, Platycephidae, Pleuronectidae and Triglidae were collected. FamilyGobiidae had the most number of taxa with 13 genera and 10 species. Greatest fish abundancehappened in August and secondarily in April and May. Species richness was evident in the warmermonths particularly in May (17 taxa, August (21 taxa, September (15 taxa and October (17 taxa.Marine teleosts significantly contributed to the species richness and abundance of fish, whichcorresponded to 52.9% (10,046 individuals of the total catch while the estuarine fishes were the secondmost abundant group with 33.5% (6,372 individuals of the total catch. Species dominance was acoherent feature of this community. The proportional contribution of marine teleosts to the fishcommunity decreased with increase distance upstream while that of estuarine fishes increased withincrease distance upstream. The developmental stages of gobies range from larvae to adult but juvenilesconstitute 77.06% of the total sample. The distribution of developmental stage of estuarine gobies wasinfluenced to a greater extent by variation in monthly water temperature and station or the interaction ofboth. Adult estuarine gobies had the tendency to aggregate in the middle estuary reflecting their hightolerance to a wide range of water salinity inherent in this station but avoided the lower estuary mostlikely due to the predominance of high salinity waters.

  7. Impact of an oceanic port (Sines, Portugal on the fish community

    Directory of Open Access Journals (Sweden)

    Nuno Mamede

    2015-10-01

    These results suggest that this port may provide favorable conditions for the occurrence of a greater fish diversity and abundance than outside areas, particularly for some species that live in subtidal rocky substrates. Recreational and commercial fishing interdiction, in place in most areas of this port for several years, may be responsible for these patterns.

  8. Offshore windfarms and their impact on fish abundance and community structure

    DEFF Research Database (Denmark)

    Stenberg, Claus; Dinesen, Grete E.; Deurs, Mikael van;

    2012-01-01

    Deployment of offshore windfarms (OWF) is rapidly expanding. A before–after control impact (BACI) approach was used to study the impact of one of the world’s largest offshore windfarms (Horns Rev Offshore Windfarm) on fish assemblages and species diversity. Fish were generally more abundant...

  9. The impact of artisanal fishery on a tropical intertidal benthic fish community

    NARCIS (Netherlands)

    de Boer, WF; van Schie, AMP; Jocene, DF; Mabote, ABP; Guissamulo, A

    2001-01-01

    We examined the benthic fishes and artisanal fishery in the intertidal flats of Inhaca Island, Mozambique. Results of a questionnaire indicated that catches had decreased, and that piscivorous fish have disappeared. Results of a catch sampling study indicated that current catch rates are low, <2 kg

  10. The impact of artisanal fishery on a tropical intertidal benthic fish community

    NARCIS (Netherlands)

    de Boer, WF; van Schie, AMP; Jocene, DF; Mabote, ABP; Guissamulo, A

    2001-01-01

    We examined the benthic fishes and artisanal fishery in the intertidal flats of Inhaca Island, Mozambique. Results of a questionnaire indicated that catches had decreased, and that piscivorous fish have disappeared. Results of a catch sampling study indicated that current catch rates are low, <2 kg

  11. Testing for adaptive evolution of the female reproductive protein ZPC in mammals, birds and fishes reveals problems with the M7-M8 likelihood ratio test

    Directory of Open Access Journals (Sweden)

    Berlin Sofia

    2005-11-01

    Full Text Available Abstract Background Adaptive evolution appears to be a common feature of reproductive proteins across a very wide range of organisms. A promising way of addressing the evolutionary forces responsible for this general phenomenon is to test for adaptive evolution in the same gene but among groups of species, which differ in their reproductive biology. One can then test evolutionary hypotheses by asking whether the variation in adaptive evolution is consistent with the variation in reproductive biology. We have attempted to apply this approach to the study of a female reproductive protein, zona pellucida C (ZPC, which has been previously shown by the use of likelihood ratio tests (LRTs to be under positive selection in mammals. Results We tested for evidence of adaptive evolution of ZPC in 15 mammalian species, in 11 avian species and in six fish species using three different LRTs (M1a-M2a, M7-M8, and M8a-M8. The only significant findings of adaptive evolution came from the M7-M8 test in mammals and fishes. Since LRTs of adaptive evolution may yield false positives in some situations, we examined the properties of the LRTs by several different simulation methods. When we simulated data to test the robustness of the LRTs, we found that the pattern of evolution in ZPC generates an excess of false positives for the M7-M8 LRT but not for the M1a-M2a or M8a-M8 LRTs. This bias is strong enough to have generated the significant M7-M8 results for mammals and fishes. Conclusion We conclude that there is no strong evidence for adaptive evolution of ZPC in any of the vertebrate groups we studied, and that the M7-M8 LRT can be biased towards false inference of adaptive evolution by certain patterns of non-adaptive evolution.

  12. The hydraulic management of the Barra Bonita reservoir (SP, Brazil as a factor influencing the temporal succession of its fish community

    Directory of Open Access Journals (Sweden)

    ML. Petesse

    Full Text Available The temporal succession of fish communities allows evaluating the environmental conditions and the adaptation capacity of the fish species to anthropogenic stress in reservoirs. The fish community at Barra Bonita reservoir was sampled in two different periods of the year (dry and rainy and in three different areas of the reservoir (fluvial, transition, and lentic. The species list was compared to another four lists, trying to detect the transformations of the fish community for the last 15 years. In order to evaluate the adaptation of the present fish community to the hydraulic management of reservoir, the trophic and reproductive structures were studied. Temporal succession analysis shows little change in fish richness of the communities. The number of fish species varies between 23 and 39 for a total of 68 registered species. From this, 27 can be considered constant, 14 accessory and 27 accidental; the main differences observed were for Anostomidae, Loricariidae and Characidae families. In relation to the hydraulic management, we found a fish community stabilized and adapted to environmental stress. This is characterized by the dominance of small-sized fish species of opportunistic diet and high reproductive compensation (r-strategists. The overlap of biological cycles of the most abundant species with the reservoir level fluctuations points to the period from September to March-April as critical for reproductive success and only the species with partial reproductive strategy or parental care are best succeeded. These results, interpreted in the context of the reservoir aging process, indicate that Barra Bonita reservoir is entering a transition phase, between the colonization and aging stages.

  13. The evolution of coexistence: Reciprocal adaptation promotes the assembly of a simple community.

    Science.gov (United States)

    Bassar, Ronald D; Simon, Troy; Roberts, William; Travis, Joseph; Reznick, David N

    2017-02-01

    Species coexistence may result by chance when co-occurring species do not strongly interact or it may be an evolutionary outcome of strongly interacting species adapting to each other. Although patterns like character displacement indicate that coexistence has often been an evolutionary outcome, it is unclear how often the evolution of coexistence represents adaptation in only one species or reciprocal adaptation among all interacting species. Here, we demonstrate a strong role for evolution in the coexistence of guppies and killifish in Trinidadian streams. We experimentally recreated the temporal stages in the invasion and establishment of guppies into communities that previously contained only killifish. We combined demographic responses of guppies and killifish with a size-based integral projection model to calculate the fitness of the phenotypes of each species in each of the stages of community assembly. We show that guppies from locally adapted populations that are sympatric with killifish have higher fitness when paired with killifish than guppies from allopatric populations. This elevated fitness involves effects traceable to both guppy and killifish evolution. We discuss the implications of our results to the study of species coexistence and how it may be mediated through eco-evolutionary feedbacks. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  14. A RAD-tag genetic map for the platyfish (Xiphophorus maculatus) reveals mechanisms of karyotype evolution among teleost fish.

    Science.gov (United States)

    Amores, Angel; Catchen, Julian; Nanda, Indrajit; Warren, Wesley; Walter, Ron; Schartl, Manfred; Postlethwait, John H

    2014-06-01

    Mammalian genomes can vary substantially in haploid chromosome number even within a small taxon (e.g., 3-40 among deer alone); in contrast, teleost fish genomes are stable (24-25 in 58% of teleosts), but we do not yet understand the mechanisms that account for differences in karyotype stability. Among perciform teleosts, platyfish (Xiphophorus maculatus) and medaka (Oryzias latipes) both have 24 chromosome pairs, but threespine stickleback (Gasterosteus aculeatus) and green pufferfish (Tetraodon nigroviridis) have just 21 pairs. To understand the evolution of teleost genomes, we made a platyfish meiotic map containing 16,114 mapped markers scored on 267 backcross fish. We tiled genomic contigs along the map to create chromosome-length genome assemblies. Genome-wide comparisons of conserved synteny showed that platyfish and medaka karyotypes remained remarkably similar with few interchromosomal translocations but with numerous intrachromosomal rearrangements (transpositions and inversions) since their lineages diverged ∼120 million years ago. Comparative genomics with platyfish shows how reduced chromosome numbers in stickleback and green pufferfish arose by fusion of pairs of ancestral chromosomes after their lineages diverged from platyfish ∼195 million years ago. Zebrafish and human genomes provide outgroups to root observed changes. These studies identify likely genome assembly errors, characterize chromosome fusion events, distinguish lineage-independent chromosome fusions, show that the teleost genome duplication does not appear to have accelerated the rate of translocations, and reveal the stability of syntenies and gene orders in teleost chromosomes over hundreds of millions of years.

  15. Composition and structure of the larval fish community related to environmental parameters in a tropical estuary impacted by climate change

    Science.gov (United States)

    Sloterdijk, Hans; Brehmer, Patrice; Sadio, Oumar; Müller, Hanno; Döring, Julian; Ekau, Werner

    2017-10-01

    Mangrove ecosystems have long been considered essential habitats and are commonly viewed and referred to as "nursery areas". They are highly sensitive to climate change, and environmental transformations in these ecosystems are expected. The Sine Saloum estuary is a case of a system affected by global climate change where reduced precipitation and temperature increase have resulted in an inversion of the salinity gradient. Within the estuary, the composition and structure of the larval fish community related to environmental parameters were investigated using neuston and ring trawl nets. Larval fishes were sampled at 16 stations distributed along a salinity and distance-to-the-sea gradient during four field campaigns (November 2013, February, June, and August 2014) covering an annual cycle. This is the first study documenting the spatial and temporal assemblages of fish larvae in an inverse estuary. The total of 41 taxa representing 24 families and 34 genus identified in this study was lower than that of other tropical estuaries. Clupeidae spp. was the dominant taxon, accounting for 28.9% of the total number of fish larvae caught, followed by Gerreidae spp. (21.1%), Hyporamphus picarti (18.8%), Diplodus bellottii (8.9%), Hypleurochilus langi (4.8%), Mugilidae spp. (4.4%), and Gobiidae sp.1 (3.5%). A total of 20 taxa were recorded within the upper estuary region, whereas 29 and 37 taxa were observed in the middle and lower reaches, respectively. While larval fish were captured at all sites and during all seasons, abundances and richness decreased with increasing salinity. Larval fish assemblages also showed a clear vertical structure corresponding to three distinct water strata. Salinity, water temperature, and dissolved oxygen were the variables that best explained the spatial and temporal differences in larval fish assemblages. It is difficult to forecast the future situation for this system but so far, compared to other mangrove estuarine systems, we have

  16. A morphospace for reef fishes: elongation is the dominant axis of body shape evolution.

    Directory of Open Access Journals (Sweden)

    Thomas Claverie

    Full Text Available Tropical reef fishes are widely regarded as being perhaps the most morphologically diverse vertebrate assemblage on earth, yet much remains to be discovered about the scope and patterns of this diversity. We created a morphospace of 2,939 species spanning 56 families of tropical Indo-Pacific reef fishes and established the primary axes of body shape variation, the phylogenetic consistency of these patterns, and whether dominant patterns of shape change can be accomplished by diverse underlying changes. Principal component analysis showed a major axis of shape variation that contrasts deep-bodied species with slender, elongate forms. Furthermore, using custom methods to compare the elongation vector (axis that maximizes elongation deformation and the main vector of shape variation (first principal component for each family in the morphospace, we showed that two thirds of the families diversify along an axis of body elongation. Finally, a comparative analysis using a principal coordinate analysis based on the angles among first principal component vectors of each family shape showed that families accomplish changes in elongation with a wide range of underlying modifications. Some groups such as Pomacentridae and Lethrinidae undergo decreases in body depth with proportional increases in all body regions, while other families show disproportionate changes in the length of the head (e.g., Labridae, the trunk or caudal region in all combinations (e.g., Pempheridae and Pinguipedidae. In conclusion, we found that evolutionary changes in body shape along an axis of elongation dominates diversification in reef fishes. Changes in shape on this axis are thought to have immediate implications for swimming performance, defense from gape limited predators, suction feeding performance and access to some highly specialized habitats. The morphological modifications that underlie changes in elongation are highly diverse, suggesting a role for a range of

  17. A morphospace for reef fishes: elongation is the dominant axis of body shape evolution.

    Science.gov (United States)

    Claverie, Thomas; Wainwright, Peter C

    2014-01-01

    Tropical reef fishes are widely regarded as being perhaps the most morphologically diverse vertebrate assemblage on earth, yet much remains to be discovered about the scope and patterns of this diversity. We created a morphospace of 2,939 species spanning 56 families of tropical Indo-Pacific reef fishes and established the primary axes of body shape variation, the phylogenetic consistency of these patterns, and whether dominant patterns of shape change can be accomplished by diverse underlying changes. Principal component analysis showed a major axis of shape variation that contrasts deep-bodied species with slender, elongate forms. Furthermore, using custom methods to compare the elongation vector (axis that maximizes elongation deformation) and the main vector of shape variation (first principal component) for each family in the morphospace, we showed that two thirds of the families diversify along an axis of body elongation. Finally, a comparative analysis using a principal coordinate analysis based on the angles among first principal component vectors of each family shape showed that families accomplish changes in elongation with a wide range of underlying modifications. Some groups such as Pomacentridae and Lethrinidae undergo decreases in body depth with proportional increases in all body regions, while other families show disproportionate changes in the length of the head (e.g., Labridae), the trunk or caudal region in all combinations (e.g., Pempheridae and Pinguipedidae). In conclusion, we found that evolutionary changes in body shape along an axis of elongation dominates diversification in reef fishes. Changes in shape on this axis are thought to have immediate implications for swimming performance, defense from gape limited predators, suction feeding performance and access to some highly specialized habitats. The morphological modifications that underlie changes in elongation are highly diverse, suggesting a role for a range of developmental processes

  18. The evolution of the placenta drives a shift in sexual selection in livebearing fish

    NARCIS (Netherlands)

    Pollux, B.J.A.; Meredith, R.W.; Springer, M.S.; Garland, T.; Reznick, D.N.

    2014-01-01

    The evolution of the placenta from a non-placental ancestor causes a shift of maternal investment from pre- to post-fertilization, creating a venue for parent–offspring conflicts during pregnancy1, 2, 3, 4. Theory predicts that the rise of these conflicts should drive a shift from a reliance on

  19. PCB contamination in fish community from the Gironde Estuary (France): blast from the past.

    Science.gov (United States)

    Bodin, N; Tapie, N; Le Ménach, K; Chassot, E; Elie, P; Rochard, E; Budzinski, H

    2014-03-01

    The contamination of the Gironde Estuary, southwest of France, by polychlorinated biphenyls (PCBs) was assessed using six fish of high ecological and economic importance as bioindicator species. The concentrations of 21 PCB congeners and total fat contents were determined in the muscle and liver of eels (Anguilla anguilla), seabass (Dicentrarchus labrax), flounders (Platichthys flesus), meagres (Argyrosomus regius), mullets (Liza ramada), and soles (Solea vulgaris). In addition, information regarding the trophic ecology of the studied fish was obtained through the analysis of carbon and nitrogen stable isotopes (i.e., δ(13)C and δ(15)N) in muscle. Results revealed high PCB concentrations in fish compared to monitored European estuaries. The muscle of eels was by far the most contaminated fish flesh (Σ7PCBs=1000±440 ng g(-1) on a dry weight basis), while the higher PCB concentrations in liver were measured in flounder (Σ7PCBs=2040±1160 ng g(-1) d.w.). A quantile regression approach allowed to investigate the fate of PCBs in the Gironde estuarine fish assemblage, and revealed a general process of trophic magnification. Finally, most of the analysed fish presented PCB concentrations in muscle meat above the current European maximum limits for sea products, while the derived "Toxic Equivalent Quantity" (TEQ) revealed human health concerns only for high-fat fish consumption. Copyright © 2014. Published by Elsevier Ltd.

  20. Fish community structure and dynamics in a coastal hypersaline lagoon: Rio Lagartos, Yucatan, Mexico

    Science.gov (United States)

    Vega-Cendejas, Ma. Eugenia; Hernández de Santillana, Mireya

    2004-06-01

    Rio Lagartos, a tropical coastal lagoon in northern Yucatan Peninsula of Mexico, is characterized by high salinity during most of the year (55 psu annual average). Even though the area has been designated as a wetland of international importance because of its great biodiversity, fish species composition and distribution are unknown. To determine whether the salinity gradient was influencing fish assemblages or not, fish populations were sampled seasonally by seine and trawl from 1992 to 1993 and bimonthly during 1997. We identified 81 fish species, eight of which accounted for 53.1% considering the Importance Value Index ( Floridichthys polyommus, Sphoeroides testudineus, Eucinostomus argenteus, Eucinostomus gula, Fundulus majalis, Strongylura notata, Cyprinodon artifrons and Elops saurus). Species richness and density declined from the mouth to the inner zone where extreme salinity conditions are prominent (>80) and competitive interactions decreased. However, in Coloradas basin (53 average sanity) and in the inlet of the lagoon, the highest fish density and number of species were observed. Greater habitat heterogeneity and fish immigration were considered as the best explanation. Multivariate analysis found three zones distinguished by fish occurrence, abundance and distribution. Ichthyofaunal spatial differences were attributed to selective recruitment from the Gulf of Mexico due to salinity gradient and to changing climatic periods. Estuarine and euryhaline marine species are abundant, with estuarine dependent ones entering the system according to environmental preferences. This knowledge will contribute to the management of the Special Biosphere Reserve through baseline data to evaluate environmental and anthropogenic changes.

  1. Trophic designation and live coral cover predict changes in reef-fish community structure along a shallow to mesophotic gradient in Hawaii

    Science.gov (United States)

    Kane, Corinne N.; Tissot, Brian N.

    2017-09-01

    Reef-fish community structure and habitat associations are well documented for shallow coral reefs (reefs (mesophotic reefs; >30 m). We documented the community structure of fishes and seafloor habitat composition through visual observations at depth intervals from 3 to 50 m in West Hawaii. Community structure changed gradually with depth, with more than 78% of fish species observed at mesophotic depths also found in shallow reef habitats. Depth explained 17% of the variation in reef-fish community structure; live coral cover explained 10% and prevalence of sand accounted for 7% of the fitted variation indicating that depth-related factors and coral habitat play a predominant role in structuring these communities. Differences in community structure also appear to be linked closely with feeding behavior. Trophic designation accounted for 31% of the fitted variation, with changes in herbivore abundance accounting for 10% of the variation. These findings suggest that changes in reef-fish community composition from shallow to mesophotic environments are largely influenced by trophic position, coral habitat and indirect effects of depth itself.

  2. Composition of fish communities in macrotidal salt marshes of the Mont Saint-Michel bay (France)

    OpenAIRE

    Laffaille, Pascal; FEUNTEUN, ERIC; Lefeuvre, Jean-Claude

    2000-01-01

    International audience; At least 100 fish species are known to be present in the intertidal areas (estuaries, mudflats and salt marshes) of Mont Saint-Michel Bay. These and other comparable shallow marine coastal waters, such as estuaries and lagoons, play a nursery role for many fish species. However, in Europe little attention has been paid to the value of tidal salt marshes for fishes. Between March 1996 and April 1999, 120 tides were sampled in a tidal creek. A total of 31 species were ca...

  3. Life history traits of the fish community in Lake Annecy: evidence from the stable isotope composition of otoliths

    Directory of Open Access Journals (Sweden)

    Gerdeaux D.

    2015-01-01

    Full Text Available Stable isotope analysis (SIA of fish otoliths shows great potential for exploring the ecology of fish, but this method has not been applied to the study of lacustrine fish communities. Both sequential and whole-otolith SIAs were performed on six fish species of Lake Annecy and their results compared to muscle SIA. The first purpose of these investigations was to test the use of δ18Ooto values for reconstructing fish thermal history and delimiting spatial distribution in a stratified lake. Comparison of species-specific fractionation equations and the general equation developed for freshwater fishes showed that the general one was the best suited for thermal estimation of Lake Annecy fishes and suggested that inter-specific differences or specific “vital effects” are not the only reason for apparent difference in fractionation. Thermal estimations based on SIA were consistent with descriptions of thermal habitats in the literature, except in the case of roach (Rutilus rutilus. Based on the current results, roach appears to live in a colder habitat than do perch (Perca fluviatilis. The high water transparency and thermal stratification of Lake Annecy could explain this distribution. Moreover, perch juveniles were found to live in two different thermal niches. This finding highlights the great plasticity of the species. Second, the potential use of δ13Coto values to reconstruct variation in diet and metabolism was assessed. The proportion of metabolic carbon (M contributing to otolith carbon varies markedly among species. Comparison with δ13Cmuscle values shows no direct relationship between δ13Coto and diet at either the intra-individual or the inter-specific level. A strong linear relationship between either M or the isotopic offset between otolith and muscle (Δδ13Coto - muscle and δ18Ooto values was found; this relationship reveals the dependence of M on the ambient temperature at which the species occurs. This relationship might be

  4. Molecular Evolution of Multiple Arylalkylamine N-Acetyltransferase (AANAT in Fish

    Directory of Open Access Journals (Sweden)

    Bina Zilberman-Peled

    2011-05-01

    Full Text Available Arylalkylamine N-acetyltransferase (AANAT catalyzes the transfer of an acetyl group from acetyl coenzyme A (AcCoA to arylalkylamines, including indolethylamines and phenylethylamines. Multiple aanats are present in teleost fish as a result of whole genome and gene duplications. Fish aanat1a and aanat2 paralogs display different patterns of tissue expression and encode proteins with different substrate preference: AANAT1a is expressed in the retina, and acetylates both indolethylamines and phenylethylamines; while AANAT2 is expressed in the pineal gland, and preferentially acetylates indolethylamines. The two enzymes are therefore thought to serve different roles. Here, the molecular changes that led to their specialization were studied by investigating the structure-function relationships of AANATs in the gilthead seabream (sb, Sperus aurata. Acetylation activity of reciprocal mutated enzymes pointed to specific residues that contribute to substrate specificity of the enzymes. Inhibition tests followed by complementary analyses of the predicted three-dimensional models of the enzymes, suggested that both phenylethylamines and indolethylamines bind to the catalytic pocket of both enzymes. These results suggest that substrate selectivity of AANAT1a and AANAT2 is determined by the positioning of the substrate within the catalytic pocket, and its accessibility to catalysis. This illustrates the evolutionary process by which enzymes encoded by duplicated genes acquire different activities and play different biological roles.

  5. The Utility of Geometric Morphometrics to Elucidate Pathways of Cichlid Fish Evolution

    Directory of Open Access Journals (Sweden)

    Michaela Kerschbaumer

    2011-01-01

    Full Text Available Fishes of the family Cichlidae are famous for their spectacular species flocks and therefore constitute a model system for the study of the pathways of adaptive radiation. Their radiation is connected to trophic specialization, manifested in dentition, head morphology, and body shape. Geometric morphometric methods have been established as efficient tools to quantify such differences in overall body shape or in particular morphological structures and meanwhile found wide application in evolutionary biology. As a common feature, these approaches define and analyze coordinates of anatomical landmarks, rather than traditional counts or measurements. Geometric morphometric methods have several merits compared to traditional morphometrics, particularly for the distinction and analysis of closely related entities. Cichlid evolutionary research benefits from the efficiency of data acquisition, the manifold opportunities of analyses, and the potential to visualize shape changes of those landmark-based methods. This paper briefly introduces to the concepts and methods of geometric morphometrics and presents a selection of publications where those techniques have been successfully applied to various aspects of cichlid fish diversification.

  6. The evolution of bourgeois, parasitic, and cooperative reproductive behaviors in fishes.

    Science.gov (United States)

    Taborsky, M

    2001-01-01

    Among vertebrate classes, fishes exhibit by far the greatest variability in competitive and cooperative behaviors in male reproduction. Scramble competition between reproductive males is one possibility. Another possibility occurs when resources, mates, or locations can be monopolized, in which case males may invest in primary access to fertilizations by adopting a "bourgeois" strategy, or they may employ alternative mating tactics to evade the reproductive monopoly of other males. Adaptations in morphology, physiology, and behavior to bourgeois and alternative phenotypes are highly divergent. Here I review the functional characteristics that differ between bourgeois and parasitic phenotypes, and discuss the variability of alternative reproductive tactics at the levels of plasticity, determination, and selection. Examples will illustrate the importance of ecology, and will suggest that variation in reproductive tactics is largely adaptive. Behavioral solutions to competition for mates and fertilizations often involve agonistic behavior and conflict, but also cooperation among competitors (e.g., when subordinate males pay a price to bourgeois males for gaining access to fertilizable eggs). Application of molecular genetic tools has helped to uncover intricate sexual and social relationships in various fish species, including species that display some of the most complex reproductive and social patterns known among the vertebrates.

  7. Effects of a non-native cichlid fish (African jewelfish, Hemichromis letourneuxi Sauvage 1880) on a simulated Everglades aquatic community

    Science.gov (United States)

    Schofield, Pamela J.; Slone, Daniel H.; Gregoire, Denise R.; Loftus, William F.

    2014-01-01

    In an 8-month mesocosm experiment, we examined how a simulated Everglades aquatic community of small native fishes, snails, and shrimp changed with the addition of either a native predator (dollar sunfish Lepomis marginatus) or a non-native predator (African jewelfish Hemichromis letourneuxi) compared to a no-predator control. Two snail species (Planorbella duryi, Physella cubensis) and the shrimp (Palaemonetes paludosus) displayed the strongest predator-treatment effects, with significantly lower biomasses in tanks with Hemichromis. One small native fish (Heterandria formosa) was significantly less abundant in Hemichromis tanks, but there were no significant treatment effects for Gambusia holbrooki, Jordanella floridae, or Pomacea paludosa (applesnail). Overall, there were few treatment differences between native predator and no-predator control tanks. The results suggest that the potential of Hemichromis to affect basal food-web species that link primary producers with higher-level consumers in the aquatic food web, with unknown consequences for Florida waters.

  8. Pallid Sturgeon Population Assessment and Associated Fish Community Monitoring for the Missouri River: Segment 14

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Pallid Sturgeon (Scaphirhynchus albus) have declined throughout the Missouri River since dam construction and inception of the Bank Stabilization and Navigation...

  9. Fish community structures in Zostera and non-Zostera regions of the ...

    African Journals Online (AJOL)

    regions of the Kromme estuary, St Francis Bay. N. Hanekom and D. .... over the entire sampling period (January 1980-September 1981). The numbers of fish ... zoobenthos or zooplankton. In a few ..... Series No 18. pp.1 - 205. Mimeograph.

  10. Biscayne National Park study on reef fish community changes over time

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Reef fish assemblage structure was assessed in 20062007 (recent period) in Biscayne National Park, Florida, USA , and compared with data collected from 1977 to 1981...

  11. Modelling Fish Habitat Suitability in the Eastern English Channel. Application to community habitat level

    OpenAIRE

    Vaz, Sandrine; Carpentier, Andre; Loots, Christophe; Koubbi, Philippe

    2004-01-01

    Valuable marine habitats and living resources can be found in the Eastern English Channel and in 2003, a Franco-British Interreg IIIA project, ‘Eastern Channel Habitat Atlas for Marine Resource Management’ (CHARM), was initiated to support decision-making for management of essential fish habitats. Fish habitat corresponds to geographic areas within which ranges of environmental factors define the presence of a particular species. Habitat Suitability index (HSI) modelling was used to relate fi...

  12. Fishes of the Vitória-Trindade Chain: Biodiversity, Biogeography and Evolution

    OpenAIRE

    Pinheiro,Hudson Tercio

    2016-01-01

    Studies on the ecology and biogeography of seamounts and oceanic islands have advanced substantially in the last 60 years. However, few seamounts have been scientifically characterized, with basic aspects of their biodiversity still unknown and many hypotheses not empirically tested. Consequently, the role of seamounts in the evolution for marine species is still unclear. In the south Atlantic, the Vitória-Trindade Chain (VTC) extends ca. 1,200 km offshore the Brazilian coast. For a long time...

  13. Water-Quality and Fish-Community Data for the Niobrara National Scenic River, Nebraska, 2003-05

    Science.gov (United States)

    Dietsch, Benjamin

    2008-01-01

    In 1991, a 76-mile reach of the Niobrara River in north-central Nebraska was designated as a National Scenic River (NSR). This reach of the river hosts a unique ecosystem that provides habitat for a diverse fish and wildlife population that include several threatened and endangered species. The Niobrara NSR also is a popular destination for campers, canoeists, kayakers, and tubers. Changes in surface-water quality, related to recreation, industrial and municipal discharge, and agricultural activities in the region have the potential to affect fish and wildlife populations within the Niobrara NSR. Additionally, water users may be at risk if elevated concentrations of chemical or biological contaminants are present in the waterway. The U.S. Geological Survey (USGS) and the National Park Service (NPS) began a 3-year cooperative study of water-quality characteristics in Niobrara NSR in 2003. During the study, water samples were collected for analysis of a suite of physical, chemical, and biological indicators of water quality in the Niobrara River. The resulting data have been published previously (Hitch and others, 2004; Hitch and others, 2005) and included: major ions, nutrients, trace elements, pesticides, organic (wastewater) compounds, bacteria, and suspended sediment. In addition to water-quality sampling, fish communities were sampled to identify the presence and diversity of species at selected sites (data available online in Annual Water Data Reports). These water-quality and fish-community data are summarized in this report. The data were collected to provide baseline information that will help NPS managers determine if changes in recreational activities, land-use practices, and other factors are affecting the Niobrara River.

  14. Cascading effects of fishing on Galapagos rocky reef communities: reanalysis using corrected data

    Science.gov (United States)

    Sonnenholzner, Jorge I.; Ladah, Lydia B.; Lafferty, Kevin D.

    2009-01-01

    This article replaces Sonnenholzner et al. (2007; Mar Ecol Prog Ser 343:77–85), which was retracted on September 19, 2007, due to errors in entry of data on sea urchins. We sampled 10 highly fished and 10 (putatively) lightly fished shallow rocky reefs in the southeastern area of the Galapagos Marine Reserve, Ecuador. After the correction, these are the new results: there was a negative association between slate-pencil urchins Eucidaris galapagensis and non-coralline algae. In addition, pencil urchins were less abundant where there were many predators. An indirect positive association between predators and non-coralline algae occurred. Fishing appeared to affect this trophic cascade. The spiny lobster Panulirus penicillatus, the slipper lobster Scyllarides astori, and the Mexican hogfish Bodianus diplotaenia were significantly less abundant at highly fished sites. Urchin density was higher at highly fished sites. Non-coralline algae were nearly absent from highly fished sites, where a continuous carpet of the anemone Aiptasia sp. was recorded, and the algal assemblage was mainly structured by encrusting coralline and articulated calcareous algae.

  15. Mineralization of PAHs in coal-tar impacted aquifer sediments and associated microbial community structure investigated with FISH

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, S.W.; Ong, S.K.; Moorman, T.B. [Iowa State University, Ames, IA (USA)

    2007-11-15

    The microbial community structure and mineralization of polycyclic aromatic hydrocarbons (PAHs) in a coal-tar contaminated aquifer were investigated spatially using fluorescence in situ hybridization (FISH) and in laboratory-scale incubations of the aquifer sediments. DAPI-detected microbial populations in the contaminated sediments were three orders of magnitude greater than nearby uncontaminated sediments, suggesting growth on coal-tar constituents in situ. Actinobacteria, {beta}- and {gamma}-Proteobacteria, and Flavobacteria dominated the in situ aerobic (> 1 mg l{sup -1} dissolved oxygen) microbial community, whereas sulfate-reducing bacteria comprised 37% of the microbial community in the sulfidogenic region of the aquifer. Rapid mineralization of naphthalene and phenanthrene were observed in aerobic laboratory microcosms and resulted in significant enrichment of {beta}- and {gamma}-Proteobacteria potentially explaining their elevated presence in situ. Nitrate- and sulfate-limited mineralization of naphthalene in laboratory microcosms occurred to a small degree in aquifer sediments from locations where groundwater chemistry indicated nitrate- and sulfate-reduction, respectively. The results of this study suggest that FISH may be a useful tool for providing a link between laboratory microcosms and groundwater measurements made in situ necessary to better demonstrate the potential for natural attenuation at complex PAH contaminated sites.

  16. Evolution of microhabitat association and morphology in a diverse group of cryptobenthic coral reef fishes (Teleostei: Gobiidae: Eviota)

    KAUST Repository

    Tornabene, Luke

    2013-01-01

    Gobies (Teleostei: Gobiidae) are an extremely diverse and widely distributed group and are the second most species rich family of vertebrates. Ecological drivers are key to the evolutionary success of the Gobiidae. However, ecological and phylogenetic data are lacking for many diverse genera of gobies. Our study investigated the evolution of microhabitat association across the phylogeny of 18 species of dwarfgobies (genus Eviota), an abundant and diverse group of coral reef fishes. In addition, we also explore the evolution of pectoral fin-ray branching and sensory head pores to determine the relationship between morphological evolution and microhabitat shifts. Our results demonstrate that Eviota species switched multiple times from a facultative hard-coral association to inhabiting rubble or mixed sand/rubble habitat. We found no obvious relationship between microhabitat shifts and changes in pectoral fin-ray branching or reduction in sensory pores, with the latter character being highly homoplasious throughout the genus. The relative flexibility in coral-association in Eviota combined with the ability to move into non-coral habitats suggests a genetic capacity for ecological release in contrast to the strict obligate coral-dwelling relationship commonly observed in closely related coral gobies, thus promoting co-existence through fine scale niche partitioning. The variation in microhabitat association may facilitate opportunistic ecological speciation, and species persistence in the face of environmental change. This increased speciation opportunity, in concert with a high resilience to extinction, may explain the exceptionally high diversity seen in Eviota compared to related genera in the family. © 2012 Elsevier Inc.

  17. Evolution of the immune system influences speciation rates in teleost fishes.

    Science.gov (United States)

    Malmstrøm, Martin; Matschiner, Michael; Tørresen, Ole K; Star, Bastiaan; Snipen, Lars G; Hansen, Thomas F; Baalsrud, Helle T; Nederbragt, Alexander J; Hanel, Reinhold; Salzburger, Walter; Stenseth, Nils C; Jakobsen, Kjetill S; Jentoft, Sissel

    2016-10-01

    Teleost fishes constitute the most species-rich vertebrate clade and exhibit extensive genetic and phenotypic variation, including diverse immune defense strategies. The genomic basis of a particularly aberrant strategy is exemplified by Atlantic cod, in which a loss of major histocompatibility complex (MHC) II functionality coincides with a marked expansion of MHC I genes. Through low-coverage genome sequencing (9-39×), assembly and comparative analyses for 66 teleost species, we show here that MHC II is missing in the entire Gadiformes lineage and thus was lost once in their common ancestor. In contrast, we find that MHC I gene expansions have occurred multiple times, both inside and outside this clade. Moreover, we identify an association between high MHC I copy number and elevated speciation rates using trait-dependent diversification models. Our results extend current understanding of the plasticity of the adaptive immune system and suggest an important role for immune-related genes in animal diversification.

  18. Evolution of Fish-Shaped Reptiles (reptilia: Ichthyopterygia) in Their Physical Environments and Constraints

    Science.gov (United States)

    Motani, Ryosuke

    2005-01-01

    Ichthyosaurs were a group of Mesozoic marine reptiles that evolved fish-shaped body outlines. They are unique in several anatomical characters, including the possession of enormous eyeballs sometimes exceeding 25 cm and an enlarged manus with sometimes up to 20 bones in a single digit, or 10 digits per manus. They are also unique in that their biology has been studied from the perspective of physical constraints, which allowed estimation of such characteristics as optimal cruising speed, visual sensitivity, and even possible basal metabolic rate ranges. These functional inferences, although based on physical principles, obviously contain errors arising from the limitations of fossilized data, but are necessarily stronger than the commonly made inferences based on superficial correlations among quantities without mechanical or optical explanations for why such correlations exist.

  19. Divergent Evolution of Male Aggressive Behaviour: Another Reproductive Isolation Barrier in Extremophile Poeciliid Fishes?

    Directory of Open Access Journals (Sweden)

    David Bierbach

    2012-01-01

    Full Text Available Reproductive isolation among locally adapted populations may arise when immigrants from foreign habitats are selected against via natural or (inter-sexual selection (female mate choice. We asked whether also intrasexual selection through male-male competition could promote reproductive isolation among populations of poeciliid fishes that are locally adapted to extreme environmental conditions [i.e., darkness in caves and/or toxic hydrogen sulphide (H2S]. We found strongly reduced aggressiveness in extremophile Poecilia mexicana, and darkness was the best predictor for the evolutionary reduction of aggressiveness, especially when combined with presence of H2S. We demonstrate that reduced aggression directly translates into migrant males being inferior when paired with males from nonsulphidic surface habitats. By contrast, the phylogenetically old sulphur-endemic P. sulphuraria from another sulphide spring area showed no overall reduced aggressiveness, possibly indicating evolved mechanisms to better cope with H2S.

  20. Evolution of a Functional Head Joint in Deep-Sea Fishes (Stomiidae)

    Science.gov (United States)

    Johnson, G. David

    2017-01-01

    The head and anterior trunk region of most actinopterygian fishes is stiffened as, uniquely within vertebrates, the pectoral girdles have a direct and often strong connection through the posttemporal to the posterior region of the skull. Members of the mesopelagic fish family Stomiidae have their pectoral girdle separated from the skull. This connection is lost in several teleost groups, but the stomiids have an additional evolutionary novelty—a flexible connection between the occiput and the first vertebra, where only the notochord persists. Several studies suggested that stomiids engulf significantly large prey items and conjectured about the functional role of the anterior part of the vertebral column; however, there has been no precise anatomical description of this complex. Here we describe a unique configuration comprising the occiput and the notochordal sheath in Aristostomias, Eustomias, Malacosteus, Pachystomias, and Photostomias that represents a true functional head joint in teleosts and discuss its potential phylogenetic implications. In these genera, the chordal sheath is folded inward ventrally beneath its connection to the basioccipital and embraces the occipital condyle when in a resting position. In the resting position (wherein the head is not manipulatively elevated), this condyle is completely embraced by the ventral fold of the notochord. A manual manipulative elevation of the head in cleared and stained specimens unfolds the ventral sheath of the notochord. As a consequence, the cranium can be pulled up and back significantly farther than in all other teleost taxa that lack such a functional head joint and thereby can reach mouth gapes up to 120°. PMID:28146571

  1. Community structure and coral status across reef fishing intensity gradients in Palk Bay reef, southeast coast of India.

    Digital Repository Service at National Institute of Oceanography (India)

    Manikandan, B.; Ravindran, J.; Shrinivaasu, S.; Marimuthu, N.; Paramasivam, K.

    the neighbouring reefs, it becomes important to maintain a no fishing zones of reef fish in the neighbourhood of reef fishing hotspots. In addition, long term data on diversity, quantity, age, size structure and sex of the reef fishes exploited...

  2. Evolution of bower building in Lake Malawi cichlid fish: Phylogeny, morphology, and behavior

    Directory of Open Access Journals (Sweden)

    Ryan eYork

    2015-03-01

    Full Text Available Despite considerable research, we still know little about the proximate and ultimate causes behind behavioral evolution. This is partly because understanding the forces acting on behavioral phenotypes requires the study of species-rich clades with extensive variation in behavioral traits, of which we have few current examples. In this paper, we introduce the bower-building cichlids of the Lake Malawi adaptive radiation, a lineage with over 100 species, each possessing a distinct male extended phenotype used to signal reproductive fitness. Extended phenotypes are useful units of analysis for the study of behavior since they are static structures that can be precisely measured within populations. To this end we recognize two core types of bowers - mounds (castles and depressions (pits. We employ an established framework for the study of adaptive radiations to ask how traits related to other stages of radiations, macrohabitat and feeding morphology, are associated with the evolution of pit and castle phenotypes. We demonstrate that pits and castles are evolutionarily labile traits and have been derived numerous times in multiple Malawi genera. Using public ecological and phenotypic data sets we find significant and correlated differences in macrohabitat (depth, sensory ability (opsin expression, and feeding style (jaw morphology and biomechanics between pit-digging and castle-building species. Phylogeny-corrected comparisons also show significant differences in several measures of jaw morphology while indicating non-significant differences in depth. Finally, using laboratory observations we assay courtship behaviors in a pit-digging (Copadichromis virginalis and a castle-building species (Mchenga conophoros. Together, these results show that traits at multiple biological levels act to regulate the evolution of a courtship behavior within natural populations.

  3. An Evaluation of the Role of Sensory Drive in the Evolution of Lake Malawi Cichlid Fishes

    Directory of Open Access Journals (Sweden)

    Adam R. Smith

    2012-01-01

    Full Text Available Although the cichlids of Lake Malawi are an important model system for the study of sensory evolution and sexual selection, the evolutionary processes linking these two phenomena remain unclear. Prior works have proposed that evolutionary divergence is driven by sensory drive, particularly as it applies to the visual system. While evidence suggests that sensory drive has played a role in the speciation of Lake Victoria cichlids, the findings from several lines of research on cichlids of Lake Malawi are not consistent with the primary tenets of this hypothesis. More specifically, three observations make the sensory drive model implausible in Malawi: (i a lack of environmental constraint due to a broad and intense ambient light spectrum in species rich littoral habitats, (ii pronounced variation in receiver sensory characteristics, and (iii pronounced variability in male courtship signal characteristics. In the following work, we synthesize the results from recent studies to draw attention to the importance of sensory variation in cichlid evolution and speciation, and we suggest possible avenues of future research.

  4. Lipid droplet biology and evolution illuminated by the characterization of a novel perilipin in teleost fish

    Science.gov (United States)

    Granneman, James G; Kimler, Vickie A; Zhang, Huamei; Ye, Xiangqun; Luo, Xixia; Postlethwait, John H; Thummel, Ryan

    2017-01-01

    Perilipin (PLIN) proteins constitute an ancient family important in lipid droplet (LD) formation and triglyceride metabolism. We identified an additional PLIN clade (plin6) that is unique to teleosts and can be traced to the two whole genome duplications that occurred early in vertebrate evolution. Plin6 is highly expressed in skin xanthophores, which mediate red/yellow pigmentation and trafficking, but not in tissues associated with lipid metabolism. Biochemical and immunochemical analyses demonstrate that zebrafish Plin6 protein targets the surface of pigment-containing carotenoid droplets (CD). Protein kinase A (PKA) activation, which mediates CD dispersion in xanthophores, phosphorylates Plin6 on conserved residues. Knockout of plin6 in zebrafish severely impairs the ability of CD to concentrate carotenoids and prevents tight clustering of CD within carotenoid bodies. Ultrastructural and functional analyses indicate that LD and CD are homologous structures, and that Plin6 was functionalized early in vertebrate evolution for concentrating and trafficking pigment. DOI: http://dx.doi.org/10.7554/eLife.21771.001 PMID:28244868

  5. Integrating evolution into geographical ecology: a phylogenetic perspective on palm distributions and community composition across scales

    DEFF Research Database (Denmark)

    Eiserhardt, Wolf L.; Svenning, J.-C.; Kissling, W. Daniel;

    Species distributions, assemblage composition, and species richness depend on both current environment and the diversification of lineages in past environments. On broad scales, processes that constrain diversifying lineages to certain regions or environments are particularly important. Through...... species pool effects, those processes also affect local community composition and richness. In addition, evolution directly affects local communities directly via niche-based assembly. We studied these effects with palms (Arecaceae) as a model group, using a) a dataset including >340,000 palm individuals...... in 430 transects in the Western Amazon, b) a set of range maps for all American palms (550 spp.), and c) global country-level presence/ absence data of all (>2400) palm species. These data were analysed with novel phylogenetic community structure and turnover methods. Globally, the phylogenetic structure...

  6. Meiotic chromosomes and stages of sex chromosome evolution in fish: zebrafish, platyfish and guppy.

    Science.gov (United States)

    Traut, W; Winking, H

    2001-01-01

    We describe SC complements and results from comparative genomic hybridization (CGH) on mitotic and meiotic chromosomes of the zebrafish Danio rerio, the platyfish Xiphophorus maculatus and the guppy Poecilia reticulata. The three fish species represent basic steps of sex chromosome differentiation: (1) the zebrafish with an all-autosome karyotype; (2) the platyfish with genetically defined sex chromosomes but no differentiation between X and Y visible in the SC or with CGH in meiotic and mitotic chromosomes; (3) the guppy with genetically and cytogenetically differentiated sex chromosomes. The acrocentric Y chromosomes of the guppy consists of a proximal homologous and a distal differential segment. The proximal segment pairs in early pachytene with the respective X chromosome segment. The differential segment is unpaired in early pachytene but synapses later in an 'adjustment' or 'equalization' process. The segment includes a postulated sex determining region and a conspicuous variable heterochromatic region whose structure depends on the particular Y chromosome line. CGH differentiates a large block of predominantly male-specific repetitive DNA and a block of common repetitive DNA in that region.

  7. Evolution of melanocortin receptors in cartilaginous fish: melanocortin receptors and the stress axis in elasmobranches.

    Science.gov (United States)

    Liang, Liang; Reinick, Christina; Angleson, Joseph K; Dores, Robert M

    2013-01-15

    There is general agreement that the presence of five melanocortin receptor genes in tetrapods is the result of two genome duplications that occurred prior to the emergence of the gnathostomes, and at least one local gene duplication that occurred early in the radiation of the ancestral gnathostomes. Hence, it is assumed that representatives from the extant classes of gnathostomes (i.e., Chondrichthyes, Actinopterygii, Sarcopterygii) should also have five paralogous melanocortin genes. Current studies on cartilaginous fishes indicate that while there is evidence for five paralogous melanocortin receptor genes in this class, to date all five paralogs have not been detected in the genome of a single species. This mini-review will discuss the ligand selectivity properties of the melanocortin-3 receptor of the elephant shark (subclass Holocephali) and the ligand selectivity properties of the melanocortin-3 receptor, melanocortin-4 receptor, and the melanocortin-5 receptor of the dogfish (subclass Elasmobranchii). The potential relationship of these melanocortin receptors to the hypothalamus/pituitary/interrenal axis will be discussed.

  8. Scombroid fishes provide novel insights into the trait/rate associations of molecular evolution.

    Science.gov (United States)

    Qiu, Fan; Kitchen, Andrew; Burleigh, J Gordon; Miyamoto, Michael M

    2014-06-01

    The study of which life history traits primarily affect molecular evolutionary rates is often confounded by the covariance of these traits. Scombroid fishes (billfishes, tunas, barracudas, and their relatives) are unusual in that their mass-specific metabolic rate is positively associated with body size. This study exploits this atypical pattern of trait variation, which allows for direct tests of whether mass-specific metabolic rate or body size is the more important factor of molecular evolutionary rates. We inferred a phylogeny for scombroids from a supermatrix of molecular and morphological characters and used new phylogenetic comparative approaches to assess the associations of body size and mass-specific metabolic rate with substitution rate. As predicted by the body size hypothesis, there is a negative correlation between body size and substitution rate. However, unexpectedly, we also find a negative association between mass-specific metabolic and substitution rates. These relationships are supported by analyses of the total molecular data, separate mitochondrial and nuclear genes, and individual loci, and they are robust to phylogenetic uncertainty. The molecular evolutionary rates of scombroids are primarily tied to body size. This study demonstrates that groups with novel patterns of trait variation can be particularly informative for identifying which life history traits are the primary factors of molecular evolutionary rates.

  9. Lake depth rather than fish planktivory determines cladoceran community structure in Faroese lakes - evidence from contemporary data and sediments

    DEFF Research Database (Denmark)

    Amsinck, S.L.; Strzelczak, A.; Bjerring, R.

    2006-01-01

    1. This study describes the environmental conditions and cladoceran community structure of 29 Faroese lakes with special focus on elucidating the impact of fish planktivory. In addition, long-term changes in biological structure of the Faroese Lake Heygsvatn are investigated. 2. Present-day species...... richness and community structure of cladocerans were identified from pelagial snapshot samples and from samples of surface sediment (0-1 cm). Multivariate statistical methods were applied to explore cladoceran species distribution relative to measured environmental variables. For Lake Heygsvatn, lake...... development was inferred by cladoceran-based paleolimnological investigations of a 14C-dated sediment core covering the last ca 5700 years. 3. The 29 study lakes were overall shallow, small-sized, oligotrophic and dominated by brown trout (Salmo trutta). Cladoceran species richness was overall higher...

  10. Voluntary medical male circumcision for HIV prevention in fishing communities in Uganda: the influence of local beliefs and practice.

    Science.gov (United States)

    Mbonye, Martin; Kuteesa, Monica; Seeley, Janet; Levin, Jonathan; Weiss, Helen; Kamali, Anatoli

    2016-09-01

    Local beliefs and practices about voluntary medical male circumcision (VMMC) may influence uptake and effectiveness. Data were gathered through interviews with 40 people from four ethnically mixed fishing communities in Uganda. Some men believed that wound healing could be promoted by contact with vaginal fluids while sex with non-regular partners could chase away spirits - practices which encouraged unsafe sexual practices. Information given by providers stressed that VMMC did not afford complete protection from sexually-transmitted infections, however, a number of male community members held the view that they were fully protected once circumcised. Both men and women said that VMMC was good not just for HIV prevention but also as a way of maintaining hygiene among the men. The implementation of VMMC in high-HIV prevalence settings needs to take account of local beliefs about circumcision, working with local religious/social group leaders, women and peers in the roll-out of the intervention.

  11. OPTIMALISASI ZONA PEMANFAATAN WISATA TAMAN NASIONAL KARIMUNJAWA MELALUI KOMUNITAS IKAN KARANG (Optimizing The Tourism Utilization Zone Karimunjawa National Park through Coral Reef Fish Communities

    Directory of Open Access Journals (Sweden)

    Rohmani Sulisyati

    2016-07-01

    . Diving pemula dilakukan pada pulau-pulau dengan resiko penyelaman rendah dan sedikit famili, sementara untuk advanced dilakukan pada pulau-pulau dengan sumberdaya tinggi dan beragam famili ikan.  ABSTRACT Ecotourism was closely related to environmental conservation that could be mutually supported and valuated. Conservation related with the communities condition. The tourism utilization zone required the coral reef fish communities as a tourist attraction. The aim of the study was optimized the tourist utilization zone Karimunjawa National Park for tourism activities through coral reef fish communities. Coral reef fish data collected on a belt transect by a visual census, record families and the number of fishes are found and the approximate total length of fish. The research conducted  during November 2013 at 14 locations.  The transect was deployed at two depth variations i.e 3 and 6–8 meters to represent the shallow and the deep water. Quantitative analysis was done to measure the fish abundance and diversity index, evenness index and domination. The result showed in the shallow water found 18 coral fish families. Chaetodontidae, Labridae and Scaridae can be found at all locations. Fish abundance is moderate which a condition of fish community depressed to stable. While the deep water, there were 17 families. Caesionidae, Chaetodontidae, Labridae, and Scaridae can found in all locations. Fish abundance is moderate which a condition of fish community depressed to stable. In the shallow waters of the outer west island inhabited by a group of major fish with a little family; the center of the archipelago encountered diverse fish families and the outer islands west and east there is a dominance of fish. The islands were located in the middle of the islands suitable for snorkeling. In the deep waters were divided four groups of islands i.e. islands with fair coral cover and the few families of coral reef fish, islands which had a fair coral cover with abundant fish

  12. [Distribution and abundance of fish community in the littoral area of "Los Petenes" Biosphere Reserve, Campeche, Mexico].

    Science.gov (United States)

    Muñoz-Rojas, Sandra; Ayala-Pérez, Luis Amado; Sosa-López, Atahualpa; Villalobos-Zapata, Guillermo Jorge

    2013-03-01

    "Los Petenes" Biosphere Reserve (RBLP) is a critical habitat for many aquatic and terrestrial species. It has the biggest and better conserved seagrass beds, and it represents an important habitat for food, protection and breeding of aquatic organisms, and a temporal refuge for migratory species. The objective of this study was to describe the ichthyofauna diversity in the littoral coastal area of the RBLP, to identify the ecological dominant species, and to analyze the abundance of the fish community and its temporal and spatial changes, and their relationship with some environmental variables. Monthly fish samples were obtained with the aid of trawl nets, from 24 samplings sites distributed along the reserve, between May 2009 and April 2010. The trawl net was operated 288 times and 21 795 individuals with 279.5kg of weight were collected. A total of 46 fish species grouped in 34 genera and 23 families were identified. In a spatial scale, the abundance showed the next ranges: 0.018-0.094ind./m2; 0.249-1.072 g/m2 and 9.75-19.32g/ind.; the diversity indexes obtained were: H'n=1.46-2.15, J'=0.45-0.71 and D'=2.08-3.92. In a temporal scale, the abundance and diversity ranged between: 0.026-0.066ind./m2; 0.342-0.764g/m2 and 6.49-22.98g/ind.; H'n=1.76-2.08; J'=0.52-0.64 and D'=3.07-4.18. Eleven dominant species were identified with a representation of the 94.39% in number of individuals, and 89.66% in weight of the total catch. From the total, eight species had economic or commercial importance, especially Lagodon rhomboides and Haemulon plumierii. The cluster analyses identified four fish associations; these results are discussed in order to identify relationships between habitat-species. Finally, the canonical correspondence analysis evidenced an association between H. plumierii with salinity and dissolved solids. The RBLP has high habitat diversity and its fish community has developed strategies to use all the spatial and temporal conditions and to satisfy the needs

  13. [Environmental heterogeneity and its relationship with diversity and abundance of the fish community in a coastal system of Gulf of Mexico].

    Science.gov (United States)

    Aguirre-León, Arturo; Pérez-Ponce, Hilda Elín; Díaz-Ruiz, Silvia

    2014-03-01

    The coastal lagoons of Veracruz, Gulf of Mexico, include a great variety of biological resources. These resources, especially fish communities, have been barely described and that require more ecological studies. With this aim, this investigation analyzed the spatial and temporal variation of diversity, abundance and assemblages of the fish community and its relationship with physical-chemical parameters of the Chica-Grande coastal system. For this, eight defined sites were monthly sampled for water characteristics and fish community composition (10min hauls of 1 500m2 a shrimp trawl net), between September 2005 and November 2006. The spatial-temporal variation of physical-chemical parameters, allowed the definition of two contrasting environments according to salinity, temperature, transparency, dissolved oxygen and depth gradients. A total of 1 947 fishes were collected for a total weight of 57.88kg. From these, 22 species, 20 genera and 14 families were identified; and four species were new records for the system. As it was detected for the physical-chemical conditions, the diversity of the fish community also showed a spatial gradient, with high values (H'=2.37, D=3.35, J'=0.82) in the brackish habitat, and low ones in freshwater environments. Fish abundance did not show such a marked gradient response, however, it was higher in the freshwater habitat. The highest diversity (H'=2.05) and species richness (D=2.99) was recorded during the North winds ("nortes") months (November-February), while density and biomass were higher (0.034 ind./m2, 1.42g/m2) during the rainy months (July-October). The Importance Value Index (IVI) defined six dominant species accounting for 77.8% of the fish abundance and 87.9% of total catch by weight. The Canonical Correspondence Analysis (CCA) showed that the fish-habitat relationship was explained by 68% of total variance for the two first axes, where salinity, transparency and temperature changes were the most important

  14. Evolution of Mat Strength from the Paleoarchean to the Modern: A Record of Evolving Microbial Communities?

    Science.gov (United States)

    Tice, M.; Pope, M.; Thornton, D.

    2011-12-01

    Fossil microbial mats, i.e. surface-attached communities of benthic microorganisms, form the most extensive record of life on Earth. Qualitatively changing mat morphologies from 3.43-0.56-billion-years-ago may reflect the evolution of microorganism communities or changing environmental conditions. However, mat morphogenesis is not well understood or easily quantifiable, making interpretation of the mat record difficult. We show that microbial mat cohesion increased from ~1 Pa to ~13 Pa at 2.7-billion-years-ago (Ga), and has remained high for most of the rest of Earth history. This initial increase may represent an early increase in the productivity of mat communities, a change in the composition of extracellular polymeric substances (EPS) produced by mat-formers, or a change in the composition of seawater affecting EPS strength. The appearance of early high-strength communities was coincident with the appearance of voids representing gas bubbles in the apices of conical stromatolites; together, these changes may record the emergence of productive mat communities dominated by oxygenic cyanobacteria. The earliest high-strength communities, like early bubble-forming conical stromatolites, grew in low-energy environments. The appearance of high-strength communities in shallow-water environments starting 2.63-2.52 Ga coincided with the appearance of the first barrier reef complexes. We hypothesize that the first oxygenic cyanobacteria were most competitive with anoxygenic phototrophs in diffusion-limited environments. As the cyanobacteria became more proficient at oxygenic photosynthesis, they eventually outcompeted anoxygenic phototrophs in higher-energy environments. Competition with higher strength seaweed and grazing by metazoans has displaced mat communities from essentially all modern high-energy niches.

  15. Fish community modeling agents on an artificial reef on the northern coast of Rio de Janeiro - Brazil

    Directory of Open Access Journals (Sweden)

    Daniel Shimada Brotto

    2006-12-01

    Full Text Available Stationary visual census surveys were performed on an experimental artificial reef (21º29'S, 41º00'W to clarify the role of structural complexity and benthic community as fish community modeling agents. Concrete modules of four types were grouped according to the combination of structural complexity through the presence/absence of holes and favourable/unfavourable surface for benthic colonization by anti-fouling painting. The survey (December 2002 to March 2003 showed higher abundance, richness and diversity in the complex modules. The same habitat usage pattern was observed according to vertical position and bottom type categories: demersal, hard-bottom and habitat generalist fishes preferred the complex ones. A higher number of juveniles occurred at those modules. It is assumed that trophic relationships and different habitat selection related to ontogenetic stages are also important modeling agents to the fish community structure since juvenile fish seem to actively seek the experimental complex modules.Censos visuais estacionários foram realizados em um recife artificial (21º29'S, 41º00'W para determinar o papel da complexidade estrutural e da comunidade bêntica como agentes modeladores da comunidade íctica. Módulos de concreto foram agrupados de acordo com a combinação do fator complexidade estrutural através da presença/ausência de cavidades internas nos módulos e de superfícies favoráveis/desfavoráveis à colonização da comunidade bêntica através de tinta anti-incrustante. De dezembro de 2002 a março de 2003, foram registrados maiores valores de abundância, riqueza e diversidade nos módulos complexos. Padrões de uso de habitat similares foram observados de acordo com a posição vertical na coluna de água e tipo de fundo: peixes demersais, de fundo consolidado e habitat generalista preferiram módulos complexos. Os resultados indicam que relações tróficas e seleção de habitat relacionada ao estágio ontogen

  16. Electrofishing as a sampling technique for coastal stream fish populations and communities in the Southeast of Brazil.

    Science.gov (United States)

    Mazzoni; Fenerich-Verani; Caramaschi

    2000-05-01

    Electrofishing adequacy was tested as a technique to obtain quantitative data of coastal stream fish populations and communities in the Southeast of Brazil. Seven field trips, between July/94 and July/95, were done in 5 localities of the Ubatiba fluvial system (Maricá, RJ). Seventeen species, among the 22 collected, had their numbers estimated through the Zipping method, the model used to test the sampling methodology. At each field trip, three removals with electrofishing were done in each locality and, according to the number of obtained species at each locality/field trip, we analysed 315 cases. Nineteen cases, among 315, showed failure condition. Estimates were significant (p catchability and the estimated number of individuals and/or environmental characteristics. High values for sampling efficiency (> 85%) were found for all estimates. An experimental analyses were done for one locality and, the comparison between the estimates for 3 and 6 successive removals showed a mean error and a standard deviation of 5.5% and 2.1% respectively. Therefore, it can be concluded that electrofishing was an efficient method for quantitative data analysis of fish populations and communities in the Ubatiba fluvial system.

  17. Rapid assessment of visual impairment (RAVI in marine fishing communities in South India - study protocol and main findings

    Directory of Open Access Journals (Sweden)

    Madala Sreenivas R

    2011-09-01

    Full Text Available Abstract Background Reliable data are a pre-requisite for planning eye care services. Though conventional cross sectional studies provide reliable information, they are resource intensive. A novel rapid assessment method was used to investigate the prevalence and causes of visual impairment and presbyopia in subjects aged 40 years and older. This paper describes the detailed methodology and study procedures of Rapid Assessment of Visual Impairment (RAVI project. Methods A population-based cross-sectional study was conducted using cluster random sampling in the coastal region of Prakasam district of Andhra Pradesh in India, predominantly inhabited by fishing communities. Unaided, aided and pinhole visual acuity (VA was assessed using a Snellen chart at a distance of 6 meters. The VA was re-assessed using a pinhole, if VA was Results The data collection was completed in Conclusion There is a high prevalence of visual impairment in marine fishing communities in Prakasam district in India. The data from this rapid assessment survey can now be used as a baseline to start eye care services in this region. The rapid assessment methodology (RAVI reported in this paper is robust, quick and has the potential to be replicated in other areas.

  18. Picoplankton Community Composition by CARD-FISH and Flow Cytometric Techniques: A Preliminary Study in Central Adriatic Sea Water

    Directory of Open Access Journals (Sweden)

    Anita Manti

    2012-01-01

    Full Text Available Data concerning picoplanktonic community composition and abundance in the Central Adriatic Sea are presented in an effort to improve the knowledge of bacterioplankton and autotrophic picoplankton and their seasonal changes. Flow cytometry analyses revealed the presence of two distinct bacteria populations: HNA and LNA cells. HNA cells showed an explicit correlation with viable and actively respiring cells. The study of viability and activity may increase our knowledge of the part that contributes really to the remineralization and bacterial biomass production. Authotrophic picoplankton abundance, especially picocyanobacteria, was strongly influenced by seasonality, indicating that light availability and water temperature are very important regulating factors. In terms of total carbon biomass, the main contribution came from heterotrophic bacteria with a lower contribution from autotrophic picoplankton. CARD-FISH evidenced, within the Eubacteria domain, the dominance of members of the phyla Alphaproteobacteria, with a strong contribution from SAR11clade, followed by Cytophaga-Flavobacterium and Gammaproteobacteria. The bacterial groups detected contributed differently depending when the sample was taken, suggesting possible seasonal patterns. This study documents for the first time picoplankton community composition in the Central Adriatic Sea using two different approaches, FCM and CARD-FISH, and could provide preliminary data for future studies.

  19. Effects of drought and pluvial periods on fish and zooplankton communities in prairie lakes: systematic and asystematic responses.

    Science.gov (United States)

    Starks, Elizabeth; Cooper, Ryan; Leavitt, Peter R; Wissel, Björn

    2014-04-01

    The anticipated impacts of climate change on aquatic biota are difficult to evaluate because of potentially contrasting effects of temperature and hydrology on lake ecosystems, particularly those closed-basin lakes within semiarid regions. To address this shortfall, we quantified decade-scale changes in chemical and biological properties of 20 endorheic lakes in central North America in response to a pronounced transition from a drought to a pluvial period during the early 21st century. Lakes exhibited marked temporal changes in chemical characteristics and formed two discrete clusters corresponding to periods of substantially different effective moisture (as Palmer Drought Severity Index, PDSI). Discriminant function analysis (DFA) explained 90% of variability in fish assemblage composition and showed that fish communities were predicted best by environmental conditions during the arid interval (PDSI climatic variability on hydrology and the strong subsequent links to water chemistry and biota indicate that future changes in global climate could result in significant restructuring of aquatic communities. Together these findings suggest that semiarid lakes undergoing temporary climate shifts provide a useful model system for anticipating the effects of global climate change on lake food webs.

  20. Relationship between cyanobacteria community and water quality parameters on intertidal zone of fish ponds, Blanakan, West Java

    Science.gov (United States)

    Takarina, N. D.; Wardhana, W.

    2017-07-01

    The presence of cyanobacteria in the intertidal zone is strongly influenced by changes in physical and chemical parameters. In milkfish ponds, cyanobacteria community had been indirectly affected by the mixing of sea water and fresh water during low tides. To determine the relationship between the cyanobacteria community and water quality parameters, phytoplankton samples were taken both vertically and horizontally in three fish ponds at Blanakan Village on July and August 2016. The water quality parameters measured were temperature, DO, salinity, and pH. Based on the enumeration results of 36 samples of phytoplankton, 5 genus Cyanobacteria (Merismopedia, Microcystis, Lyngbya, Oscillatoria and Trichodesmium) were obtained. Cyanobacteria is a subdominant group after diatomae with dominance index between 2-21 %. Average of density ranged between 128-3563 plankters /10 dm3. High dominance level (97-99 %) between cyanobacteria and diatoms cause phytoplankton diversity indices in all three fish ponds were very small (0.0851 to 0.8734). Based on the analysis of the three main components (Principle Component Analysis) it was known that the presence of five cyanobacteria genus was determined by the differences of water quality parameters observed. Merismopedia was more affected by salinity and DO fluctuations. Oscillatoria, Trichodesmium and Lyngbya were determined by changes in temperature, whereas Microcystis was more affected by pH.

  1. Global study of probiotic effect on gut microbial communities in fish larvae

    Science.gov (United States)

    The goal of this project was to test the long term effects of early microbial colonization on fish gut microbiota composition. To do so, axenically raised tilapia larvae were either reared under conventional conditions in activated suspension tanks (AST) or first exposed to a single strain probioti...

  2. Carbon sources supporting a diverse fish community in a tropical coastal ecosystem (Gazi Bay, Kenya)

    NARCIS (Netherlands)

    Nyunja, J.; Ntiba, M.; Onyari, J.; Mavuti, K.; Soetaert, K.E.R.; Bouillon, S.

    2009-01-01

    Interlinked mangrove–seagrass ecosystems are characteristic features of many tropical coastal areas, where they act as feeding and nursery grounds for a variety of fishes and invertebrates. The autotrophic carbon sources supporting fisheries in Gazi bay (Kenya) were studied in three sites, two locat

  3. Fish community of a small, temperate, urban river in South Africa

    African Journals Online (AJOL)

    2015-10-05

    Oct 5, 2015 ... (23 km long), urban river in the Eastern Cape of South Africa that rises and ... Aonyx capensis, their use limits the maximum size of fish sampled in the .... Spearman Rank Correlation test was used to test for relation- ships between ... migrant species, the dominant, uniformly distributed alien spe- cies were ...

  4. Fish community response to dam removal in a Maine coastal river tributary

    Science.gov (United States)

    Zydlewski, Joseph; Hogg, Robert S.; Coghlan Jr., Stephen M.; Gardner, Cory

    2016-01-01

    Sedgeunkedunk Stream, a third-order tributary to the Penobscot River in Maine, historically has supported several anadromous fishes including Atlantic Salmon Salmo salar, Alewife Alosa pseudoharengus, and Sea Lamprey Petromyzon marinus. Two small dams constructed in the 1800s reduced or eliminated spawning runs entirely. In 2009, efforts to restore marine–freshwater connectivity in the system culminated in removal of the lowermost dam (Mill Dam) providing access to 4.7 km of lotic habitat and unimpeded passage into the lentic habitat of Fields Pond. In anticipation of these barrier removals, we initiated a modified before-after-control-impact study, and monitored stream fish assemblages in fixed treatment and reference sites. Electrofishing surveys were conducted twice yearly since 2007. Results indicated that density, biomass, and diversity of the fish assemblage increased at all treatment sites upstream of the 2009 dam removal. No distinct changes in these metrics occurred at reference sites. We documented recolonization and successful reproduction of Atlantic Salmon, Alewife, and Sea Lamprey in previously inaccessible upstream reaches. These results clearly demonstrate that dam removal has enhanced the fish assemblage by providing an undisrupted stream gradient linking a small headwater lake and tributary with a large coastal river, its estuary, and the Atlantic Ocean.

  5. Zooplankton, fish communities and the role of planktivory in nine Ethiopian lakes

    NARCIS (Netherlands)

    Vijverberg, J.; Dejen, E.; Getahun, A.; Nagelkerke, L.A.J.

    2014-01-01

    Fish and zooplankton populations of nine Ethiopian freshwater lakes were quantitatively sampled along a North–South gradient. Differences in altitude and latitude resulted in a temperature gradient from North to South. We tested three hypotheses: (1) the degree of zooplanktivory decreases with water

  6. Epidemiology of cholera outbreaks and socio-economic characteristics of the communities in the fishing villages of Uganda: 2011-2015.

    Science.gov (United States)

    Bwire, Godfrey; Munier, Aline; Ouedraogo, Issaka; Heyerdahl, Leonard; Komakech, Henry; Kagirita, Atek; Wood, Richard; Mhlanga, Raymond; Njanpop-Lafourcade, Berthe; Malimbo, Mugagga; Makumbi, Issa; Wandawa, Jennifer; Gessner, Bradford D; Orach, Christopher Garimoi; Mengel, Martin A

    2017-03-01

    The communities in fishing villages in the Great Lakes Region of Africa and particularly in Uganda experience recurrent cholera outbreaks that lead to considerable mortality and morbidity. We evaluated cholera epidemiology and population characteristics in the fishing villages of Uganda to better target prevention and control interventions of cholera and contribute to its elimination from those communities. We conducted a prospective study between 2011-15 in fishing villages in Uganda. We collected, reviewed and documented epidemiological and socioeconomic data for 10 cholera outbreaks that occurred in fishing communities located along the African Great Lakes and River Nile in Uganda. These outbreaks caused 1,827 suspected cholera cases and 43 deaths, with a Case-Fatality Ratio (CFR) of 2.4%. Though the communities in the fishing villages make up only 5-10% of the Ugandan population, they bear the biggest burden of cholera contributing 58% and 55% of all reported cases and deaths in Uganda during the study period. The CFR was significantly higher among males than females (3.2% vs. 1.3%, p = 0.02). The outbreaks were seasonal with most cases occurring during the months of April-May. Male children under age of 5 years, and 5-9 years had increased risk. Cholera was endemic in some villages with well-defined "hotspots". Practices predisposing communities to cholera outbreaks included: the use of contaminated lake water, poor sanitation and hygiene. Additional factors were: ignorance, illiteracy, and poverty. Cholera outbreaks were a major cause of morbidity and mortality among the fishing communities in Uganda. In addition to improvements in water, sanitation, and hygiene, oral cholera vaccines could play an important role in the prevention and control of these outbreaks, particularly when targeted to high-risk areas and populations. Promotion and facilitation of access to social services including education and reduction in poverty should contribute to cholera

  7. Patterns and drivers of fish community assembly in a large marine ecosystem

    DEFF Research Database (Denmark)

    Pécuchet, Lauréne; Törnroos, Anna; Lindegren, Martin

    2016-01-01

    shaping community composition. However, community composition in the eastern part, an area beyond the steep decline in salinity, was characterized by fewer species with largely different trait characteristics, indicating that community assembly is also affected by biotic interactions. Our results add......The presence and survival of the species in a community depend on their abilities to maximize fitness in a given environment. The study of the processes that control survival and co‑existence, termed ‘assembly rules’, follows various mechanisms, primarily related to biotic or abiotic factors....... To determine assembly rules, ecological similarities of co-occurring species are often investigated. This can be evaluated using trait-based indices summarizing the species’ niches in a given community. In order to investigate the underlying processes shaping community assembly in marine ecosystems, we...

  8. Variation in fish community structure, richness, and diversity in 56 Danish lakes with contrasting depth, size, and trophic state: does the method matter?

    DEFF Research Database (Denmark)

    Menezes, Rosemberg; Borchsenius, Finn; Svenning, J.-C.

    2013-01-01

    The distribution of freshwater fish is influenced by food availability, habitat heterogeneity, competition, predation, trophic state, and presence/absence of macrophytes. This poses a challenge to monitoring, and researchers have been struggling to develop accurate sampling methods for obtaining...... community, as all methods miss some important species that other methods capture. However, electrofishing seems to be a fast alternative to gillnets for monitoring fish species richness and composition in littoral habitats of Danish lakes....

  9. Parasite communities of the predatory fish, Acestrorhynchus falcatus and Acestrorhynchus falcirostris, living in sympatry in Brazilian Amazon

    Directory of Open Access Journals (Sweden)

    Maria Danielle Figueiredo Guimarães Hoshino

    2016-06-01

    Full Text Available Abstract This study investigated the parasite communities of wild Acestrorhynchus falcatus and Acestrorhynchus falcirostris populations living in sympatry in Brazilian Amazon. In these two hosts, a total of 12 parasite species e 1-9 parasite species were found per fish, and 10 of these species are metazoans. Eight species of parasites were common to both host species and four of them exhibited differences in abundance and/or prevalence. Parasite communities of the hosts were taxonomically similar (83% and composed of both ectoparasites and endoparasites, and characterized by high prevalence and high abundance of endoparasites and an aggregated dispersion pattern. For A. falcirostris, the dominant parasite was Ichthyophthirius multifiliis, and for A. falcatus, it was Piscinoodinium pillulare. Shannon diversity and Berger-Parker dominance were similar for both hosts, while the parasites species richness and evenness showed differences influenced by the ectoparasites species. These two populations of hosts that inhabited the same geographical area had different sizes, but were exposed to the same infective stages, and acquired qualitatively and quantitatively similar endoparasites community, thus indicating that the amounts and types of prey congeneric that they were eating were similar. Therefore, the overlap in the same occurrence area play an important role in the parasite communities to these phylogenetically related hosts.

  10. Metagenomic insights into evolution of heavy metal-contaminated groundwater microbial community

    Energy Technology Data Exchange (ETDEWEB)

    Hemme, C.L.; Deng, Y.; Gentry, T.J.; Fields, M.W.; Wu, L.; Barua, S.; Barry, K.; Green-Tringe, S.; Watson, D.B.; He, Z.; Hazen, T.C.; Tiedje, J.M.; Rubin, E.M.; Zhou, J.

    2010-07-01

    Understanding adaptation of biological communities to environmental change is a central issue in ecology and evolution. Metagenomic analysis of a stressed groundwater microbial community reveals that prolonged exposure to high concentrations of heavy metals, nitric acid and organic solvents ({approx}50 years) has resulted in a massive decrease in species and allelic diversity as well as a significant loss of metabolic diversity. Although the surviving microbial community possesses all metabolic pathways necessary for survival and growth in such an extreme environment, its structure is very simple, primarily composed of clonal denitrifying {gamma}- and {beta}-proteobacterial populations. The resulting community is overabundant in key genes conferring resistance to specific stresses including nitrate, heavy metals and acetone. Evolutionary analysis indicates that lateral gene transfer could have a key function in rapid response and adaptation to environmental contamination. The results presented in this study have important implications in understanding, assessing and predicting the impacts of human-induced activities on microbial communities ranging from human health to agriculture to environmental management, and their responses to environmental changes.

  11. Metagenomic Insights into Evolution of a Heavy Metal-Contaminated Groundwater Microbial Community

    Energy Technology Data Exchange (ETDEWEB)

    Hemme, Christopher L.; Deng, Ye; Gentry, Terry J.; Fields, Matthew W.; Wu, Liyou; Barua, Soumitra; Barry, Kerrie; Tringe, Susannah G.; Watson, David B.; He, Zhili; Hazen, Terry C.; Tiedje, James M.; Rubin, Edward M.; Zhou, Jizhong

    2010-02-15

    Understanding adaptation of biological communities to environmental change is a central issue in ecology and evolution. Metagenomic analysis of a stressed groundwater microbial community reveals that prolonged exposure to high concentrations of heavy metals, nitric acid and organic solvents (~;;50 years) have resulted in a massive decrease in species and allelic diversity as well as a significant loss of metabolic diversity. Although the surviving microbial community possesses all metabolic pathways necessary for survival and growth in such an extreme environment, its structure is very simple, primarily composed of clonal denitrifying ?- and ?-proteobacterial populations. The resulting community is over-abundant in key genes conferring resistance to specific stresses including nitrate, heavy metals and acetone. Evolutionary analysis indicates that lateral gene transfer could be a key mechanism in rapidly responding and adapting to environmental contamination. The results presented in this study have important implications in understanding, assessing and predicting the impacts of human-induced activities on microbial communities ranging from human health to agriculture to environmental management, and their responses to environmental changes.

  12. Character displacement and the evolution of niche complementarity in a model biofilm community.

    Science.gov (United States)

    Ellis, Crystal N; Traverse, Charles C; Mayo-Smith, Leslie; Buskirk, Sean W; Cooper, Vaughn S

    2015-02-01

    Colonization of vacant environments may catalyze adaptive diversification and be followed by competition within the nascent community. How these interactions ultimately stabilize and affect productivity are central problems in evolutionary ecology. Diversity can emerge by character displacement, in which selection favors phenotypes that exploit an alternative resource and reduce competition, or by facilitation, in which organisms change the environment and enable different genotypes or species to become established. We previously developed a model of long-term experimental evolution in which bacteria attach to a plastic bead, form a biofilm, and disperse to a new bead. Here, we focus on the evolution of coexisting mutants within a population of Burkholderia cenocepacia and how their interactions affected productivity. Adaptive mutants initially competed for space, but later competition declined, consistent with character displacement and the predicted effects of the evolved mutations. The community reached a stable equilibrium as each ecotype evolved to inhabit distinct, complementary regions of the biofilm. Interactions among ecotypes ultimately became facilitative and enhanced mixed productivity. Observing the succession of genotypes within niches illuminated changing selective forces within the community, including a fundamental role for genotypes producing small colony variants that underpin chronic infections caused by B. cenocepacia.

  13. Single-cell transcriptome analysis of fish immune cells provides insight into the evolution of vertebrate immune cell types

    Science.gov (United States)

    Ferreira, Lauren; Macaulay, Iain C.; Stubbington, Michael J.T.

    2017-01-01

    The immune system of vertebrate species consists of many different cell types that have distinct functional roles and are subject to different evolutionary pressures. Here, we first analyzed conservation of genes specific for all major immune cell types in human and mouse. Our results revealed higher gene turnover and faster evolution of trans-membrane proteins in NK cells compared with other immune cell types, and especially T cells, but similar conservation of nuclear and cytoplasmic protein coding genes. To validate these findings in a distant vertebrate species, we used single-cell RNA sequencing of lck:GFP cells in zebrafish and obtained the first transcriptome of specific immune cell types in a nonmammalian species. Unsupervised clustering and single-cell TCR locus reconstruction identified three cell populations, T cells, a novel type of NK-like cells, and a smaller population of myeloid-like cells. Differential expression analysis uncovered new immune-cell–specific genes, including novel immunoglobulin-like receptors, and neofunctionalization of recently duplicated paralogs. Evolutionary analyses confirmed the higher gene turnover of trans-membrane proteins in NK cells compared with T cells in fish species, suggesting that this is a general property of immune cell types across all vertebrates. PMID:28087841

  14. The Integrated Genomic Architecture and Evolution of Dental Divergence in East African Cichlid Fishes (Haplochromis chilotes x H. nyererei).

    Science.gov (United States)

    Hulsey, C Darrin; Machado-Schiaffino, Gonzalo; Keicher, Lara; Ellis-Soto, Diego; Henning, Frederico; Meyer, Axel

    2017-09-07

    The independent evolution of the two toothed jaws of cichlid fishes is thought to have promoted their unparalleled ecological divergence and species richness. However, dental divergence in cichlids could exhibit substantial genetic covariance and this could dictate how traits like tooth numbers evolve in different African Lakes and on their two jaws. To test this hypothesis, we used a hybrid mapping cross of two trophically divergent Lake Victoria species (Haplochromis chilotes × Haplochromis nyererei) to examine genomic regions associated with cichlid tooth diversity. Surprisingly, a similar genomic region was found to be associated with oral jaw tooth numbers in cichlids from both Lake Malawi and Lake Victoria. Likewise, this same genomic location was associated with variation in pharyngeal jaw tooth numbers. Similar relationships between tooth numbers on the two jaws in both our Victoria hybrid population and across the phylogenetic diversity of Malawi cichlids additionally suggests that tooth numbers on the two jaws of haplochromine cichlids might generally coevolve owing to shared genetic underpinnings. Integrated, rather than independent, genomic architectures could be key to the incomparable evolutionary divergence and convergence in cichlid tooth numbers. Copyright © 2017 Hulsey et al.

  15. The Integrated Genomic Architecture and Evolution of Dental Divergence in East African Cichlid Fishes (Haplochromis chilotes x H. nyererei

    Directory of Open Access Journals (Sweden)

    C. Darrin Hulsey

    2017-09-01

    Full Text Available The independent evolution of the two toothed jaws of cichlid fishes is thought to have promoted their unparalleled ecological divergence and species richness. However, dental divergence in cichlids could exhibit substantial genetic covariance and this could dictate how traits like tooth numbers evolve in different African Lakes and on their two jaws. To test this hypothesis, we used a hybrid mapping cross of two trophically divergent Lake Victoria species (Haplochromis chilotes × Haplochromis nyererei to examine genomic regions associated with cichlid tooth diversity. Surprisingly, a similar genomic region was found to be associated with oral jaw tooth numbers in cichlids from both Lake Malawi and Lake Victoria. Likewise, this same genomic location was associated with variation in pharyngeal jaw tooth numbers. Similar relationships between tooth numbers on the two jaws in both our Victoria hybrid population and across the phylogenetic diversity of Malawi cichlids additionally suggests that tooth numbers on the two jaws of haplochromine cichlids might generally coevolve owing to shared genetic underpinnings. Integrated, rather than independent, genomic architectures could be key to the incomparable evolutionary divergence and convergence in cichlid tooth numbers.

  16. Origin and evolution of B chromosomes in the cichlid fish Astatotilapia latifasciata based on integrated genomic analyses.

    Science.gov (United States)

    Valente, Guilherme T; Conte, Matthew A; Fantinatti, Bruno E A; Cabral-de-Mello, Diogo C; Carvalho, Robson F; Vicari, Marcelo R; Kocher, Thomas D; Martins, Cesar

    2014-08-01

    Approximately 15% of eukaryotes contain supernumerary B chromosomes. When present, B chromosomes frequently represent as much as 5% of the genome. Despite thousands of reports describing the distribution of supernumeraries in various taxa, a comprehensive theory for the origin, maintenance, and evolution of B chromosomes has not emerged. Here, we sequence the complete genomes of individual cichlid fish (Astatotilapia latifasciata) with and without B chromosomes, as well as microdissected B chromosomes, to identify DNA sequences on the B. B sequences were further analyzed through quantitative polymerase chain reaction and in situ hybridization. We find that the B chromosome contains thousands of sequences duplicated from essentially every chromosome in the ancestral karyotype. Although most genes on the B chromosome are fragmented, a few are largely intact, and we detect evidence that at least three of them are transcriptionally active. We propose a model in which the B chromosome originated early in the evolutionary history of Lake Victoria cichlids from a small fragment of one autosome. DNA sequences originating from several autosomes, including protein-coding genes and transposable elements, subsequently inserted into this proto-B. We propose that intact B chromosome genes involved with microtubule organization, kinetochore structure, recombination and progression through the cell cycle may play a role in driving the transmission of the B chromosome. Furthermore, our work suggests that karyotyping is an essential step prior to genome sequencing to avoid problems in genome assembly and analytical biases created by the presence of high copy number sequences on the B chromosome.

  17. Reproductive histology of Tomeurus gracilis Eigenmann, 1909 (Teleostei: Atherinomorpha: Poeciliidae) with comments on evolution of viviparity in atherinomorph fishes.

    Science.gov (United States)

    Parenti, Lynne R; LoNostro, Fabiana L; Grier, Harry J

    2010-11-01

    Tomeurus gracilis is a species long considered pivotal in understanding the evolution of livebearing in atherinomorph fishes. Tomeurus gracilis is a zygoparous or embryoparous poeciliid: internal fertilization is followed by females laying fertilized eggs singly or retaining fertilized eggs until or near hatching. Tomeurus was hypothesized as the sister group of the viviparous poeciliids until it was proposed as a close relative of a derived viviparous poeciliid, Cnesterodon, hence nested among viviparous taxa rather than near the root of the tree. Here, we describe and compare reproductive morphological characters of the little-known Tomeurus with those of representative atherinomorphs. In Tomeurus and Cnesterodon, sperm are packaged in naked sperm bundles, or spermatozeugmata, in a configuration considered here diagnostic of viviparous poeciliids. Testes are single and free sperm are stored in the ovary in both taxa in contrast to oviparous atherinomorphs in which testes are paired and sperm are not packaged and not stored in the ovary. Efferent ducts in Cnesterodon testes and other viviparous poeciliids have a PAS-positive secretion demonstrating presence of a glycoprotein that inactivates sperm or prevents final sperm maturation. No PAS-positive staining secretion was observed in Tomeurus or oviparous atherinomorphs. Tomeurus shares apomorphic reproductive characters, such as sperm bundle and testis morphology and a gonopodium, with viviparous poeciliids and plesiomorphic characters, such as a thick zona pellucida with filaments, with oviparous taxa. We do not postulate loss or reversal of viviparity in Tomeurus, and we corroborate its phylogenetic position as sister to the viviparous poeciliids.

  18. Fish communities and their relation to physical and chemical characteristics of streams from selected environmental settings in the Lower Susquehanna River basin, 1993-95

    Science.gov (United States)

    Bilger, Michael D.; Brightbill, Robin A.

    1998-01-01

    Studies of fish-community composition were conducted annually in selected reaches (from 100 to 303 meters in length) on seven streams from June 1993 to June 1995 within the Lower Susquehanna River Basin. In 1994, additional