WorldWideScience

Sample records for forage fish species

  1. Foraging preferences influence microplastic ingestion by six marine fish species from the Texas Gulf Coast.

    Science.gov (United States)

    Peters, Colleen A; Thomas, Peyton A; Rieper, Kaitlyn B; Bratton, Susan P

    2017-07-11

    This study evaluated the influence of foraging preferences on microplastic ingestion by six marine fish species from the Texas Gulf Coast. A total of 1381 fish were analyzed and 42.4% contained ingested microplastic, inclusive of fiber (86.4%), microbead (12.9% %), and fragment (<1.0%) forms. Despite a substantial overlap in diet, ordination of ingested prey items clustered samples into distinctive species groupings, reflective of the foraging gradient among species. Orthopristis chrysoptera displayed the lowest overall frequency of microplastic ingestion and the most distinctive ordination grouping, indicating their selective invertebrate foraging preferences. Cluster analysis of O. chrysoptera most closely classified microplastic with the ingestion of benthic invertebrates, whereas the ingestion of microplastic by all other species most closely classified with the ingestion of vegetation and shrimp. O. chrysoptera, as selective invertebrate foragers, are less likely to ingest microplastics than species exhibiting generalist foraging preferences and methods of prey capture. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2016-01-01

    Benthic foraging by fish can modify the nature and rates of fine sediment accrual and the structure and topography of coarse-grained fluvial substrates, with the potential to alter bed material characteristics, particle entrainment thresholds, and bedload transport fluxes. However, knowledge of what controls the nature, extent, and intensity of benthic foraging and the consequent influence of these controls on geomorphic impact remain rudimentary. An ex-situ experiment utilising Barbel Barbus barbus and Chub Leuciscus cephalus extended previous work by considering the role of fish size and species as controls of sediment disturbance by foraging and the implications for bed material characteristics and bedload transport. In a laboratory flume, changes in bed microtopography and structure were measured when a water-worked bed of 5.6-22.6 mm gravels was exposed to four size classes of Barbel (4-5″, 5-6″, 6-8″, 8-10″ in length) and a single size class of Chub (8-10″). In line with other studies that have investigated animal size as a control of zoogeomorphic agency, increasing the size of Barbel had a significant effect on measured disturbance and transport metrics. Specifically, the area of disturbed substrate, foraging depth, and the fish's impact on microtopographic roughness and imbrication all increased as a function of fish size. In a comparison of the foraging effects of like-sized Barbel and Chub, 8-10″ in length, Barbel foraged a larger area of the test bed and had a greater impact on microtopographic roughness and sediment structure. Relative to water-worked beds that were not foraged, bed conditioning by both species was associated with increased bedload transport during the subsequent application of high flows. However, the bedload flux after foraging by Barbel, which is a specialist benthivore, was 150% higher than that following foraging by Chub, which feed opportunistically from the bed, and the total transported mass of sediment was 98

  3. Trace elements in Antarctic fish species and the influence of foraging habitats and dietary habits on mercury levels

    Energy Technology Data Exchange (ETDEWEB)

    Goutte, Aurélie, E-mail: aurelie.goutte@ephe.sorbonne.fr [École Pratique des Hautes Études (EPHE), SPL, UPMC Univ Paris 06, UMR 7619 METIS, F-75005, 4 place Jussieu, Paris (France); Cherel, Yves [Centre d' Etudes Biologiques de Chizé, UMR 7372, CNRS-Université de La Rochelle, 79360 Villiers-en-Bois (France); Churlaud, Carine [Littoral Environnement et Sociétés (LIENSs), UMR 7266, CNRS-Université de la Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France); Ponthus, Jean-Pierre [École Pratique des Hautes Études (EPHE), SPL, UPMC Univ Paris 06, UMR 7619 METIS, F-75005, 4 place Jussieu, Paris (France); Massé, Guillaume [Unité Mixte Internationale Takuvik, Pavillon Alexandre-Vachon, Université Laval, QC, Québec (Canada); Bustamante, Paco [Littoral Environnement et Sociétés (LIENSs), UMR 7266, CNRS-Université de la Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France)

    2015-12-15

    This study aims at describing and interpreting concentration profiles of trace elements in seven Antarctic fish species (N = 132 specimens) off Adélie Land. Ichthyofauna plays a key role in the Antarctic ecosystem, as they occupy various ecological niches, including cryopelagic (ice-associated), pelagic, and benthic habitats. Firstly, trace element levels in the studied specimens were similar to those previously observed in fish from the Southern Ocean. Apart from manganese and zinc, concentrations of arsenic, cadmium, copper, iron, mercury (Hg), nickel, selenium and silver differed among fish species. Muscle δ{sup 13}C and δ{sup 15}N values were determined to investigate whether the fish foraging habitats and dietary habits could explain Hg levels. Species and foraging habitat (δ{sup 13}C) were strong predictors for variations of Hg concentrations in muscle tissues. The highest Hg contamination was found in shallow benthic fish compared to cryopelagic and pelagic fish. This pattern was likely due to the methylation of Hg in the coastal sediment and the photodemethylation by ultraviolet radiation in surface waters. - Highlights: • Trace elements and stable isotopes were analyzed in seven Antarctic fish species. • Levels of trace elements in liver and in muscle differed among species. • Hg load was higher in benthic fish than in cryopelagic and pelagic fish. • These findings could be due to the high methylation rate of Hg in the sediment.

  4. Fishing amplifies forage fish population collapses.

    Science.gov (United States)

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

    2015-05-26

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

  5. Forage fish, their fisheries, and their predators: who drives whom?

    DEFF Research Database (Denmark)

    Engelhard, Georg H.; Peck, Myron A.; Rindorf, Anna;

    2014-01-01

    The North Sea has a diverse forage fish assemblage, including herring, targeted for human consumption; sandeel, sprat, and Norway pout, exploited by industrial fisheries; and some sardine and anchovy, supporting small-scale fisheries. All show large abundance fluctuations, impacting on fisheries...... exist, as in the North Sea. Sandeel appears to be the most important prey forage fish. Seabirds are most dependent on forage fish, due to specialized diet and distributional constraints (breeding colonies). Other than fisheries, key predators of forage fish are a few piscivorous fish species including...... saithe, whiting, mackerel, and horse-mackerel, exploited in turn by fisheries; seabirds and seals have a more modest impact. Size-based foodwebmodelling suggests that reducing fishing mortality may not necessarily lead to larger stocks of piscivorous fish, especially if their early life stages compete...

  6. Fish foraging patterns, vulnerability to fishing, and implications for the management of ecosystem function across scales.

    Science.gov (United States)

    Nash, Kirsty L; Graham, Nicholas A J; Bellwood, David R

    2013-10-01

    The function of species has been recognized as critical for the maintenance of ecosystems within desired states. However, there are still considerable gaps in our knowledge of interspecific differences in the functional roles of organisms, particularly with regard to the spatial scales over which functional impact is exerted. This has implications for the delivery of function and the maintenance of ecosystem processes. In this study we assessed the allometric relationship between foraging movements and fish body length at three sites, for 20 species of herbivorous reef fishes within four different functional groups: browsers, farmers, grazer/ detritivores, and scraper/excavators. The relationship between vulnerability of species to fishing and their scale of foraging was also examined. We present empirical evidence of the strong, positive, log-linear relationship between the scale of foraging movement and fish body length. This relationship was consistent among sites and between the two different movement metrics used. Phylogeny did not affect these results. Functional groups foraged over contrasting ranges of spatial scales; for example, scraper/excavators performed their role over a wide range of scales, whereas browsers were represented by few species and operated over a narrow range of scales. Overfishing is likely not only to remove species operating at large scales, but also to remove the browser group as a whole. Large fishes typically have a significant role in removing algae on reefs, and browsers are key to controlling macroalgae and reversing shifts to macroalgal-dominated states. This vulnerability to exploitation has serious consequences for the ability of fish assemblages to deliver their functional role in the face of anthropogenic impacts. However, identification of the scales at which herbivorous fish assemblages are susceptible to fishing provides managers with critical knowledge to design management strategies to support coral-dominated reefs by

  7. Foraging Behaviour Patterns of Four Sympatric Demersal Fishes

    Science.gov (United States)

    Labropoulou, M.; Papadopoulou-Smith, K.-N.

    1999-08-01

    The trophic relationships of four sympatric demersal fish species (Mullus barbatus, Mullus surmuletus, Pagrus pagrus and Gobius niger) which dominate the shallow coastal areas (25-30 m) of Iraklion Bay (S Aegean, NE Mediterranean) were investigated from samples collected on a monthly basis (August 1990-August 1992). Stomach content analysis revealed that all four species were carnivorous, feeding mainly on benthic invertebrates. Although these species displayed different feeding modes based on principal prey type utilization, they all consumed a considerable number of polychaetes. In order to understand any underlying patterns of predation on polychaetes, prey items were identified to the lowest possible taxonomic level. The polychaete species were further classified into groups according to their microhabitat (surface or burrowing) and feeding (feeding mode, motility and morphology) guilds. Comparisons of the feeding habits were made using the percentage contribution by number of each prey species in the diet of the predators. Similarities in the diets between the fish species were calculated and cluster analysis was used to describe interspecific variations in food selection, concerning polychaetes. The predatory preferences of each fish species were related to the microhabitat distribution of prey species in the sediment. The differential exploitation of polychaete species was a good indicator of disparate foraging behaviour among the fish species examined, since it reflects a transition from a non-selective to a specialized feeding method. The effects of predator size and morphology of feeding apparatus and the availability of polychaete species in the environment are also discussed to explain the differential exploitation of polychaetes exhibited by the fish.

  8. Fatty acid composition of forage herb species

    DEFF Research Database (Denmark)

    Warner, D.; Jensen, Søren Krogh; Cone, J.W.

    2010-01-01

    The use of alternative forage species in grasslands for intensive livestock production is receiving renewed attention. Data on fatty acid composition of herbs are scarce, so four herbs (Plantago lanceolata, Achillea millefolium, Cichorium intybus, Pastinaca sativa) and one grass species (timothy......, Phleum pratense) were sown in a cutting trial. The chemical composition and concentration of fatty acids (FA) of individual species were determined during the growing season. Concentrations of crude protein and FA were generally higher in the herbs than in timothy. C. intybus had the highest nutritive...

  9. Foraging habits of reef fishes associated with mangroves and seagrass beds in a Caribbean lagoon: A stable isotope approach

    OpenAIRE

    2015-01-01

    Mangroves and seagrass beds represent suitable fish habitats as nurseries or feeding areas. This study was conducted in a Caribbean lagoon to assess the foraging habits of juvenile transient reef fishes in these two habitats. Twelve fish species were sampled in coastal mangroves, an offshore mangrove islet, and a seagrass bed site, and stable isotope analyses were performed on fishes and their prey items. The SIAR mixing model indicated that transient fishes from both mangroves and s...

  10. Conservation and Ecology of Marine Forage Fishes--Proceedings of a Research Symposium, September 2012

    Science.gov (United States)

    Liedtke, Theresa; Gibson, Caroline; Lowry, Dayv; Fagergren, Duane

    2013-01-01

    Locally and globally, there is growing recognition of the critical roles that herring, smelt, sand lance, eulachon, and other forage fishes play in marine ecosystems. Scientific and resource management entities throughout the Salish Sea, agree that extensive information gaps exist, both in basic biological knowledge and parameters critical to fishery management. Communication and collaboration among researchers also is inadequate. Building on the interest and enthusiasm generated by recent forage fish workshops and symposia around the region, the 2012 Research Symposium on the Conservation and Ecology of Marine Forage Fishes was designed to elucidate practical recommendations for science and policy needs and actions, and spur further collaboration in support for the precautionary management of forage fish. This dynamic and productive event was a joint venture of the Northwest Straits Commission Forage Fish Program, U.S. Geological Survey (USGS), Washington Department of Fish and Wildlife (WDFW), and The Puget Sound Partnership. The symposium was held on September 12–14, 2012, at the University of Washington, Friday Harbor Laboratories campus. Sixty scientists, graduate students, and fisheries policy experts convened; showcasing ongoing research, conservation, and management efforts targeting forage fish from regional and national perspectives. The primary objectives of this event were to: (1) review current research and management related to marine forage fish species; and (2) identify priority science and policy needs and actions for Washington, British Columbia, and the entire West Coast. Given the diversity of knowledge, interests, and disciplines surrounding forage fish on both sides of the international border, the organizing committee made a concerted effort to contact many additional experts who, although unable to attend, provided valuable insights and ideas to the symposium structure and discussions. The value of the symposium format was highlighted in

  11. Forage fish, their fisheries and their predators: who drives whom?

    NARCIS (Netherlands)

    Engelhard, G.H.; Peck, M.A.; Rindorf, A.; Smout, S.C.; Deurs, van M.; Raab, K.E.; Andersen, K.H.; Garthe, S.; Lauerburg, R.A.M.; Scott, F.; Brunel, T.P.A.; Aarts, G.M.; Kooten, van T.; Dickey-Collas, M.

    2014-01-01

    The North Sea has a diverse forage fish assemblage, including herring, targeted for human consumption; sandeel, sprat, and Norway pout, exploited by industrial fisheries; and some sardine and anchovy, supporting small-scale fisheries. All show large abundance fluctuations, impacting on fisheries and

  12. Nitrogen transfer between herbivores and their forage species

    NARCIS (Netherlands)

    Sjogersten, Sofie; Kuijper, Dries P. J.; van der Wal, Rene; Loonen, Maarten J. J. E.; Huiskes, Ad H. L.; Woodin, Sarah J.

    2010-01-01

    Herbivores may increase the productivity of forage plants; however, this depends on the return of nutrients from faeces to the forage plants. The aim of this study was to test if nitrogen (N) from faeces is available to forage plants and whether the return of nutrients differs between plant species

  13. Sex-specific foraging behavior in response to fishing activities in a threatened seabird.

    Science.gov (United States)

    García-Tarrasón, Manuel; Bécares, Juan; Bateman, Santiago; Arcos, José Manuel; Jover, Lluís; Sanpera, Carolina

    2015-06-01

    Some seabird species have learnt to efficiently exploit fishing discards from trawling activities. However, a discard ban has been proposed as necessary in Europe to ensure the sustainability of the seas. It is of crucial importance for the management and conservation purposes to study the potential consequences of a discard ban on the foraging ecology of threatened seabirds. We assessed the influence of fishing activities on the feeding habits of 22 male and 15 female Audouin's gulls (Larus audouinii) from the Ebro Delta (Mediterranean Sea) during the breeding period using GPS loggers together with Stable Isotope Analysis (SIA), which provided new insights into their foraging behavior and trophic ecology, respectively. GPS data revealed different sex-specific foraging patterns between workdays and weekends. Females were highly consistent in that they foraged at sea throughout the week even though discarding stops at weekends. In contrast, males switched from foraging at sea during the week (when discards are produced) to an increased use of rice field habitats at weekends (when fishermen do not work). This sex-specific foraging behavior could be related to specific nutritional requirements associated with previous egg production, an energetically demanding period for females. However, on a broader time scale integrated by the SIA, both sexes showed a high degree of individual specialization in their trophic ecology. The need to obtain detailed information on the dependence and response of seabirds to fishing activities is crucial in conservation sciences. In this regard, sex-specific foraging behavior in relation to fisheries has been overlooked, despite the ecological and conservation implications. For instance, this situation may lead to sex differentiation in bycatch mortality in longlines when trawlers do not operate. Moreover, any new fisheries policy will need to be implemented gradually to facilitate the adaptation of a specialized species to a discard ban

  14. Vermetid gastropods reduce foraging by herbivorous fishes on algae on coral reefs

    Science.gov (United States)

    Tootell, Jesse S.; Steele, Mark A.

    2014-12-01

    Vermetid gastropods have the potential to reduce foraging by herbivorous fishes on algae on coral reefs because they produce mucous nets that cover the surfaces of coral skeletons, potentially inhibiting foraging by fishes. We assessed this possibility using both observational and experimental approaches in Moorea, French Polynesia. Foraging rates of herbivorous fishes (total number of bites by all species per minute) were recorded in plots that varied naturally in the cover of vermetid mucous nets. This study, done at six sites, revealed that foraging on algal turf declined with increasing cover of vermetid mucous nets, ranging from ~2 to 22 bites m-2 min-1 at 0 % coverage to 0-5 bites m-2 min-1 at 100 % coverage. The magnitude of this effect of vermetid nets varied among microhabitats (high, mid, and low bommies) and sites, presumably due to variation in the intensity of herbivory. Experimental removal of vermetid mucous nets from plots more than doubled the foraging intensity on turf algae relative to when vermetid nets were present at high (≥70 %) cover. Our results indicate that algal turf on coral reefs may benefit from associational refuge from grazing provided by vermetid gastropods, which might in turn harm corals via increased competition with algal turf.

  15. Forage fish of the Pacific Rim as revealed by diet of a piscivorous seabird: Synchrony and relationships with sea surface temperature

    Science.gov (United States)

    Thayer, J.A.; Bertram, D.F.; Hatch, Shyla A.; Hipfner, M.J.; Slater, L.; Sydeman, W.J.; Watanuki, Y.

    2008-01-01

    We tested the hypothesis of synchronous interannual changes in forage fish dynamics around the North Pacific Rim. To do this, we sampled forage fish communities using a seabird predator, the rhinoceros auklet (Cerorhinca monocerata), at six coastal study sites from Japan to California. We investigated whether take of forage fishes was related to local marine conditions as indexed by sea surface temperature (SST). SST was concordant across sites in the eastern Pacific, but inversely correlated between east and west. Forage fish communities consisted of anchovy (Engraulis spp.), sandlance (Ammodytes spp.), capelin (Mallotus spp.), and juvenile rockfish (Sebastes spp.), among others, and take of forage fish varied in response to interannual and possibly lower-frequency oceanographic variability. Take of primary forage species were significantly related to changes in SST only at the eastern sites. We found synchrony in interannual variation of primary forage fishes across several regions in the eastern Pacific, but no significant east-west correlations. Specifically in the Japan Sea, factors other than local SST or interannual variability may more strongly influence forage fishes. Predator diet sampling offers a fishery-independent, large-scale perspective on forage fish dynamics that may be difficult to obtain using conventional means of study. ?? 2008 NRC.

  16. Biomass of deepwater demersal forage fishes in Lake Huron, 1994-2007: Implications for offshore predators

    Science.gov (United States)

    Roseman, E.F.; Riley, S.C.

    2009-01-01

    We estimated the biomass of deepwater demersal forage fishes (those species common in the diets of lake trout and Chinook salmon) in Lake Huron during the period 1994-2007. The estimated total lake-wide biomass of deepwater demersal fishes in 2007 was reduced by 87 percent of that observed in 1994. Alewife biomass remained near the record low observed in 2004. Biomass of young-of-the-year rainbow smelt was at a record high in 2005, but little recruitment appears to have occurred in 2006 or 2007. Record-high estimates of young-of-the-year bloater biomass were observed in 2005 and 2007, and an increase in the biomass of adult bloater in 2007 suggests that some recruitment may be occurring. The biomass of other potential deepwater demersal forage fish species (sculpins, ninespine stickleback, trout-perch and round goby) has also declined since 1994 and remained low in 2007. The forage fish community in 2007 was dominated by small (< 120 mm) bloater and rainbow smelt. These results suggest that lake trout and Chinook salmon in Lake Huron may face nutritional stress in the immediate future.

  17. Dworshak Reservoir Investigations: Trout, Bass and Forage Species, 1989 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Statler, David P.

    1990-07-01

    The Nez Perce Tribe and the Idaho Department of Fish and Game (IDFG) entered into separate intergovernmental agreements with the Bonneville Power Administration in a cooperative four-year effort to study impacts of Dworshak Dam operation on resident fisheries. This third annual report focuses on rainbow trout, smallmouth bass, and forage species. 22 refs., 19 figs., 11 tabs.

  18. Food of forage fishes in western Lake Erie, 1975-76

    Science.gov (United States)

    Muth, Kenneth M.; Busch, Wolf-Dieter N.

    1989-01-01

    In western Lake Erie in the summer and fall of 1975–1976, food eaten by seven forage fishes—emerald shiner (Notropis atherinoides), spottail shiner (Notropis hudsonius), trout-perch (Percopsis omiscomaycus), andyoung-of-the-year (YOY) of alewife (Alosa pseudoharengus), gizzard shad (Dorosoma cepedianum), white bass (Morone chrysops), and freshwater drum (Aplodi-notus grunniens)—was divided among six major taxa: Cladocera, Copepoda, Diptera, Ostracoda, Amphipoda, and Algae. In addition, fish were eaten by YOY white bass, and Rotifera were consumed by YOY gizzard shad. Interspecies diet overlap indices, calculated to compare the food of the different species and to evaluate diet similarities, were usually highest for YOY white bass and YOY freshwater drum when compared with the other species and usually lowest between emerald shiners and all other forage fishes. Understanding the feeding interactions among fishes that could influence production at the forage-food level of the food web could provide insight into how cascading trophic interactions influence the production of piscivorous predators.

  19. Simulating mechanisms for dispersal, production and stranding of small forage fish in temporary wetland habitats

    Science.gov (United States)

    Yurek, Simeon; DeAngelis, Donald L.; Trexler, Joel C.; Jopp, Fred; Donalson, Douglas D.

    2013-01-01

    Movement strategies of small forage fish (stranded fish in accessible depths. Expansion and contraction of seasonal wetlands induce a sequential alternation between rapid biomass growth and concentration, creating the conditions for local stranding of small fish as they move in response to varying water levels. To better understand how landscape topography, hydrology, and fish behavior interact to create high densities of stranded fish, we first simulated population dynamics of small fish, within a dynamic food web, with different traits for movement strategy and growth rate, across an artificial, spatially explicit, heterogeneous, two-dimensional marsh slough landscape, using hydrologic variability as the driver for movement. Model output showed that fish with the highest tendency to invade newly flooded marsh areas built up the largest populations over long time periods with stable hydrologic patterns. A higher probability to become stranded had negative effects on long-term population size, and offset the contribution of that species to stranded biomass. The model was next applied to the topography of a 10 km × 10 km area of Everglades landscape. The details of the topography were highly important in channeling fish movements and creating spatiotemporal patterns of fish movement and stranding. This output provides data that can be compared in the future with observed locations of fish biomass concentrations, or such surrogates as phosphorus ‘hotspots’ in the marsh.

  20. Evaluation of nutritional value some forage species available in Iran ...

    African Journals Online (AJOL)

    Novin

    2012-07-17

    Jul 17, 2012 ... between gas production parameters and CP content of forage species. The study shows that these ..... Legume, grass and legume-grass mixture quality standards. Quality standard1 ..... Temperature effects on anatomy and ...

  1. Ecosystem-based management objectives for the North Sea: riding the forage fish rollercoaster

    DEFF Research Database (Denmark)

    Dickey-Collas, Mark; Engelhard, Georg H.; Rindorf, Anna

    2014-01-01

    The North Sea provides a useful model for considering forage fish (FF) within ecosystem-based management as it has a complex assemblage of FF species. This paper is designed to encourage further debate and dialogue between stakeholders about management objectives. Changing the management of fishe......The North Sea provides a useful model for considering forage fish (FF) within ecosystem-based management as it has a complex assemblage of FF species. This paper is designed to encourage further debate and dialogue between stakeholders about management objectives. Changing the management...... of fisheries on FF will have economic consequences for all fleets in the North Sea. The predators that are vulnerable to the depletion of FF are Sandwich terns, great skua and common guillemots, and to a lesser extent, marine mammals. Comparative evaluations of management strategies are required to consider...... whether maintaining the reserves of prey biomass or a more integral approach of monitoring mortality rates across the trophic system is more robust under the ecosystem approach. In terms of trophic energy transfer, stability, and resilience of the ecosystem, FF should be considered as both a sized...

  2. Bottom-up regulation of capelin, a keystone forage species.

    Directory of Open Access Journals (Sweden)

    Alejandro D Buren

    Full Text Available The Northwest Atlantic marine ecosystem off Newfoundland and Labrador, Canada, has been commercially exploited for centuries. Although periodic declines in various important commercial fish stocks have been observed in this ecosystem, the most drastic changes took place in the early 1990s when the ecosystem structure changed abruptly and has not returned to its previous configuration. In the Northwest Atlantic, food web dynamics are determined largely by capelin (Mallotus villosus, the focal forage species which links primary and secondary producers with the higher trophic levels. Notwithstanding the importance of capelin, the factors that influence its population dynamics have remained elusive. We found that a regime shift and ocean climate, acting via food availability, have discernible impacts on the regulation of this population. Capelin biomass and timing of spawning were well explained by a regime shift and seasonal sea ice dynamics, a key determinant of the pelagic spring bloom. Our findings are important for the development of ecosystem approaches to fisheries management and raise questions on the potential impacts of climate change on the structure and productivity of this marine ecosystem.

  3. Isotopic signatures, foraging habitats and trophic relationships between fish and seasnakes on the coral reefs of New Caledonia

    Science.gov (United States)

    Brischoux, F.; Bonnet, X.; Cherel, Y.; Shine, R.

    2011-03-01

    A predator's species, sex and body size can influence the types of prey that it consumes, but why? Do such dietary divergences result from differences in foraging habitats, or reflect differential ability to locate, capture or ingest different types of prey? That question is difficult to answer if foraging occurs in places that preclude direct observation. In New Caledonia, amphibious sea kraits ( Laticauda laticaudata and L. saintgironsi) mostly eat eels—but the species consumed differ between snake species and vary with snake body size and sex. Because the snakes capture eels within crevices on the sea floor, it is not possible to observe snake foraging on any quantitative basis. We used stable isotopes to investigate habitat-divergence and ontogenetic shifts in feeding habits of sympatric species of sea kraits. Similarities in δ15 N (~10.5‰) values suggest that the two snake species occupy similar trophic levels in the coral-reef foodweb. However, δ13C values differed among the eight eel species consumed by snakes, as well as between the two snake species, and were linked to habitat types. Specifically, δ13C differed between soft- vs. hard-substrate eel species, and consistently differed between the soft-bottom forager L. laticaudata (~ -14.7‰) and the hard-bottom forager L. saintgironsi (~ -12.5‰). Differences in isotopic signatures within and between the two sea krait species and their prey were consistent with the hypothesis of habitat-based dietary divergence. Isotopic composition varied with body size within each of the snake species and varied with body size within some eel species, reflecting ontogenetic shifts in feeding habits of both the sea kraits and their prey. Our results support the findings of previous studies based on snake stomach contents, indicating that further studies could usefully expand these isotopic analyses to a broader range of trophic levels, fish species and spatial scales.

  4. Emergent Sandbar Construction for Least Terns on the Missouri River: Effects on Forage Fishes in Shallow-Water Habitats

    Science.gov (United States)

    Stucker, J.H.; Buhl, D.A.; Sherfy, M.H.

    2011-01-01

    Emergent sandbars on the Missouri River are actively managed for two listed bird species, piping plovers and interior least terns. As a plunge-diving piscivore, endangered least terns rely on ready access to appropriately sized slender-bodied fish: Engineers mechanically created several emergent sandbars on the Missouri River. However, it was unknown whether sandbar construction is a benefit or a detriment to forage abundance for least terns. Therefore, we studied the shallowwater (mechanically created emergent sandbars during three nesting seasons (2006-2008). We sampled every 2 weeks each year from late May to July within 15-16 areas to document the relative abundance, species richness and size classes of fish. Fish relative abundance was negatively related to depth. Catches were dominated by schooling species, including emerald shiner, sand shiner, spotfin shiner and bigmouth buffalo. Significant inter-annual differences in relative abundance were observed, with generally increasing trends in intra-seasonal relative abundance of shiners and the smallest size classes of fish (mechanical sandbar habitats host comparable fish communities at similar levels of relative abundance. Further analyses are required to evaluate if the levels of fish relative abundance are adequate to support least tern foraging and reproduction.

  5. Turtle cleaners: reef fishes foraging on epibionts of sea turtles in the tropical Southwestern Atlantic, with a summary of this association type

    Directory of Open Access Journals (Sweden)

    Cristina Sazima

    Full Text Available In the present study we record several instances of reef fish species foraging on epibionts of sea turtles (cleaning symbiosis at the oceanic islands of Fernando de Noronha Archipelago and near a shipwreck, both off the coast of Pernambuco State, northeast Brazil. Nine reef fish species and three turtle species involved in cleaning are herein recorded. Besides our records, a summary of the literature on this association type is presented. Postures adopted by turtles during the interaction are related to the habits of associated fishes. Feeding associations between fishes and turtles seem a localized, albeit common, phenomenon.

  6. Organochlorine and mercury residues in forage fish from littoral habitats in Green Bay, Lake Michigan

    Energy Technology Data Exchange (ETDEWEB)

    Brazner, J.; DeVita, W. [Environmental Protection Agency, Duluth, MN (United States). Environmental Research Lab.]|[Univ. of Wisconsin, Stevens Point, WI (United States). Environmental Task Force Lab.

    1995-12-31

    Forage fish were collected with a variety of gears in August and September, 1991 to characterize human disturbance at 24 coastal wetland and beach sites in Green Bay. Disturbance characterization included analysis of contaminant residues in young-of-the-year fish for at least one species per site. Yellow perch and spottail shiners were the primary species sampled, but species composition varied with location so other species were also utilized. Homogenized composites of 5 to 10 fish were analyzed for PCBs and p,p{prime}-DDE using gas chromatography/mass spectrometry (ion trap). Total mercury was determined by standard cold vapor flameless atomic absorption. There were no differences in lipid normalized residues for any of the contaminants among species, but there were differences in total PCBs, most PCB homologs, and mercury among regions. Distance from the Fox River mouth explained most of the variance (r{sup 2} = 0.81) in PCB concentrations. These ranged from an average of 11 ng/g in the upper bay to 207 ng/g in the lower bay where one yellow perch sample measured 1,076 ng/g and all 14 samples exceeded the IJC Aquatic Life Guideline of 100 ng/g. In addition, PCBs were most concentrated in beach dwelling fishes in the lower bay. Distribution of PCBs was skewed in that tri and tetrachlorobiphenyl homologs were most prevalent in the lower bay just as penta and hexachlorobiphenyl homologs were in the upper bay. Concentrations and distributions of p,p{prime}-DDE (regional means ranged from 2.8 to 4.6 ng/g) and mercury (regional means ranged from 26 to 44 ng/g) were lower and less skewed than for PCBS, suggesting primarily nonpoint sources.

  7. Grey seal predation on forage fish in the Baltic Sea

    DEFF Research Database (Denmark)

    Eero, Aro; Neuenfeldt, Stefan; Aho, Teija;

    has increased accordingly. The diet of grey seal in the Baltic consists of ca. 20 fish species. The most abundant prey items in the Baltic proper are Baltic herring, sprat, and cod, and in the Bothnian Sea and Bothnian Bay Baltic herring, Coregonus sp., Baltic salmon, and sea trout. An adult seal...... consumes on average round 4.5 kg fish per day, of which 55% are clupeoids in the Baltic Main basin and 70% in the Bothnian Sea and Bothnian Bay. According to acoustic estimates, predator– prey distribution patterns, migration patterns, and multispecies analysis (SMS), the predation effect of grey seals...... on Baltic herring and sprat stocks is still at a very low level. Hence, with present grey seal stock sizes, the impact of seal predation can be ignored in whole Baltic‐scale herring and sprat stock management considerations. Locally, however, grey seal–fishery interactions play an important role and should...

  8. The global susceptibility of coastal forage fish to competition by large jellyfish

    DEFF Research Database (Denmark)

    Schnedler-Meyer, Nicolas Azaña; Mariani, Patrizio; Kiørboe, Thomas

    2016-01-01

    , but the lack of both good quality data and a robust theoretical framework have prevented general global analyses. Here, we present a general mechanistic food web model that considers fundamental differences in feeding modes and predation pressure between fish and jellyfish. The model predicts forage fish...

  9. A day in the life of fish larvae: modeling foraging and growth using quirks.

    Directory of Open Access Journals (Sweden)

    Klaus B Huebert

    Full Text Available This article introduces "Quirks," a generic, individual-based model synthesizing over 40 years of empirical and theoretical insights into the foraging behavior and growth physiology of marine fish larvae. In Quirks, different types of larvae are defined by a short list of their biological traits, and all foraging and growth processes (including the effects of key environmental factors are modeled following one unified set of mechanistic rules. This approach facilitates ecologically meaningful comparisons between different species and environments. We applied Quirks to model young exogenously feeding larvae of four species: 5.5-mm European anchovy (Engraulis encrasicolus, 7-mm Atlantic cod (Gadus morhua, 13-mm Atlantic herring (Clupea harengus, and 7-mm European sprat (Sprattus sprattus. Modeled growth estimates explained the majority of variability among 53 published empirical growth estimates, and displayed very little bias: 0.65% ± 1.2% d(-1 (mean ± standard error. Prey organisms of ∼ 67% the maximum ingestible prey length were optimal for all larval types, in terms of the expected ingestion per encounter. Nevertheless, the foraging rate integrated over all favorable prey sizes was highest when smaller organisms made up >95% of the prey biomass under the assumption of constant normalized size spectrum slopes. The overall effect of turbulence was consistently negative, because its detrimental influence on prey pursuit success exceeded its beneficial influence on prey encounter rate. Model sensitivity to endogenous traits and exogenous environmental factors was measured and is discussed in depth. Quirks is free software and open source code is provided.

  10. Predictors of mercury spatial patterns in San Francisco Bay forage fish.

    Science.gov (United States)

    Greenfield, Ben K; Slotton, Darell G; Harrold, Katherine H

    2013-12-01

    Pollution reduction efforts should be targeted toward those sources that result in the highest bioaccumulation. For mercury (Hg) in estuaries and other complex water bodies, carefully designed biosentinel monitoring programs can help identify predictors of bioaccumulation and inform management priorities for source reduction. This study employed a probabilistic forage fish Hg survey with hypothesis testing in San Francisco Bay (California, USA). The goal was to determine what pollution sources, regions, and landscape features were associated with elevated Hg bioaccumulation. Across 99 sites, whole-body Hg concentrations in Mississippi silversides (Menidia audens) and topsmelt (Atherinops affinis) followed a broad spatial gradient, declining with distance from the Guadalupe River (Pearson's r = -0.69 and -0.42, respectively), which drains historic mining areas. Site landscape attributes and local Hg sources had subtle effects, which differed between fish species. Topsmelt Hg increased in embayment sites (i.e., enclosed sites including channels, creek mouths, marinas, and coves) and sites with historic Hg-contaminated sediment, suggesting an influence of legacy industrial and mining contamination. In 2008, Mississippi silverside Hg was reduced at sites draining wastewater-treatment plants. Fish Hg was not related to abundance of surrounding wetland cover but was elevated in some watersheds draining from historic Hg-mining operations. Results indicated both regional and site-specific influences for Hg bioaccumulation in San Francisco Bay, including legacy contamination and proximity to treated wastewater discharge. © 2013 SETAC.

  11. Germinative potential of encrusted seed of tropical forage species

    Directory of Open Access Journals (Sweden)

    José Rafael de Souza

    Full Text Available ABSTRACT: Brazil is the largest producer, consumer and exporter of seeds of forage species, thus the adoption of new technologies for expansion and maintenance of this market is of great importance. The aim of this work was to evaluate encrustation effect on germination potential in seeds of Brachiaria sp. species. The experiment was carried out in Biofabrica laboratory from June to August 2014, in Universidade Estadual do Sudoeste da Bahia, Vitória da Conquista-BA. The experimental design was completely randomized, in a factorial scheme 6x2, with two treatments (with and without coating and four replications. For germination quality of seeds were evaluated germination and vigor (emergence, emergence speed index, total length of seedling, shoot and root. The encrustation affected positively the germination of seeds in all species tested and encrustation did not affect the total length, shoot and root of the seedlings. Coating after chemical scarification is an alternative to improve germination of the seeds of tropical forage species.

  12. Foraging segregation of two congeneric diving seabird species breeding on St. George Island, Bering Sea

    Science.gov (United States)

    Kokubun, Nobuo; Yamamoto, Takashi; Sato, Nobuhiko; Watanuki, Yutaka; Will, Alexis; Kitaysky, Alexander S.; Takahashi, Akinori

    2016-04-01

    Subarctic environmental changes are expected to affect the foraging ecology of marine top predators, but the response to such changes may vary among species if they use food resources differently. We examined the characteristics of foraging behavior of two sympatric congeneric diving seabird: common (Uria aalge: hereafter COMUs) and thick-billed (U. lomvia: hereafter TBMUs) murres breeding on St. George Island, located in the seasonal sea-ice region of the Bering Sea. We investigated their foraging trip and flight durations, diel patterns of dive depth, and underwater wing strokes, along with wing morphology and blood stable isotope signatures and stress hormones. Acceleration-temperature-depth loggers were attached to chick-guarding birds, and data were obtained from 7 COMUs and 12 TBMUs. Both species showed similar mean trip duration (13.2 h for COMUs and 10.5 h for TBMUs) and similar diurnal patterns of diving (frequent dives to various depths in the daytime and less frequent dives to shallow depths in the nighttime). During the daytime, the dive depths of COMUs had two peaks in shallow (18.1 m) and deep (74.2 m) depths, while those of TBMUs were 20.2 m and 59.7 m. COMUs showed more frequent wing strokes during the bottom phase of dives (1.90 s-1) than TBMUs (1.66 s-1). Fish occurred more frequently in the bill loads of COMUs (85 %) than those of TBMUs (56 %). The δ15N value of blood was significantly higher in COMUs (14.5 ‰) than in TBMUs (13.1 ‰). The relatively small wing area (0.053 m2) of COMUs compared to TBMUs (0.067 m2) may facilitate their increased agility while foraging and allow them to capture more mobile prey such as larger fishes that inhabit deeper depths. These differences in food resource use may lead to the differential responses of the two murre species to marine environmental changes in the Bering Sea.

  13. Herbaceous plant species invading natural areas tend to have stronger adaptive root foraging than other naturalized species.

    Science.gov (United States)

    Keser, Lidewij H; Visser, Eric J W; Dawson, Wayne; Song, Yao-Bin; Yu, Fei-Hai; Fischer, Markus; Dong, Ming; van Kleunen, Mark

    2015-01-01

    Although plastic root-foraging responses are thought to be adaptive, as they may optimize nutrient capture of plants, this has rarely been tested. We investigated whether nutrient-foraging responses are adaptive, and whether they pre-adapt alien species to become natural-area invaders. We grew 12 pairs of congeneric species (i.e., 24 species) native to Europe in heterogeneous and homogeneous nutrient environments, and compared their foraging responses and performance. One species in each pair is a USA natural-area invader, and the other one is not. Within species, individuals with strong foraging responses, measured as plasticity in root diameter and specific root length, had a higher biomass. Among species, the ones with strong foraging responses, measured as plasticity in root length and root biomass, had a higher biomass. Our results therefore suggest that root foraging is an adaptive trait. Invasive species showed significantly stronger root-foraging responses than non-invasive species when measured as root diameter. Biomass accumulation was decreased in the heterogeneous vs. the homogeneous environment. In aboveground, but not belowground and total biomass, this decrease was smaller in invasive than in non-invasive species. Our results show that strong plastic root-foraging responses are adaptive, and suggest that it might aid in pre-adapting species to becoming natural-area invaders.

  14. Has eutrophication promoted forage fish production in the Baltic Sea?

    DEFF Research Database (Denmark)

    Eero, Margit; Andersson, Helén C; Almroth-Rosell, Elin

    2016-01-01

    Reducing anthropogenic nutrient inputs is a major policy goal for restoring good environmental status of coastal marine ecosystems. However, it is unclear to what extent reducing nutrients would also lower fish production and fisheries yields. Empirical examples of changes in nutrient loads and c...

  15. Linkage between fishes'foraging, market and fish stocks density: Examples from some North Sea fisheries

    NARCIS (Netherlands)

    Marchal, P.; Poos, J.J.; Quirijns, F.J.

    2007-01-01

    This study has investigated some properties of fishermen's foraging, using Levy flights theory. The case studies examined were a selection of North Sea Dutch and French vessels, for which catch and effort data were collected on a haul-by-haul basis. Foraging behavior could reasonably be represented

  16. A new approach to study of seabird-fishery overlap: Connecting chick feeding with parental foraging and overlap with fishing vessels

    Directory of Open Access Journals (Sweden)

    Junichi Sugishita

    2015-07-01

    Full Text Available Incidental fisheries bycatch is recognised as a major threat to albatross populations worldwide. However, fishery discards and offal produced in large quantities might benefit some scavenging seabirds. Here, we demonstrate an integrated approach to better understand the ecological ramifications of fine-scale overlap between seabirds and fisheries. As a case study, we examined whether foraging in association with a fishing vessel is advantageous for chick provisioning in terms of quantity of food delivered to chicks, in northern royal albatross (Diomedea sanfordi at Taiaroa Head, New Zealand. Fine-scale overlap between albatrosses and vessels was quantified by integrating GPS tracking and Vessel Monitoring Systems (VMS. Meal size delivered to chicks was measured using custom-designed nest balances, and monitoring of attendance of adults fitted with radio transmitters was used in conjunction with time-lapse photography at the nest allowed us to allocate each feeding event to a specific parent. The combination of these techniques enabled comparison of meal sizes delivered to chicks with parental foraging trip durations with or without fishing vessels association. A total of 45 foraging trips and associated chick feeding events were monitored during the chick-rearing period in 2012. Differences in the meal size and foraging trip duration relative to foraging overlap with fisheries were examined using a linear mixed-effect model, adjusted for chick age. Our results, based on three birds, suggest that foraging in association with vessels does not confer an advantage for chick feeding for this population that demonstrated low rates of overlap while foraging. The integrated research design presented can be applied to other seabird species that are susceptible to bycatch, and offers a valuable approach to evaluate habitat quality by linking habitat use and foraging success in terms of total amount of food delivered to offspring.

  17. Effect of species and harvest maturity on the fatty acids profile of tropical forages

    NARCIS (Netherlands)

    Khan, N.A.; Farooq, M.W.; Ali, M.; Suleman, M.; Ahmad, N.; Sulaiman, S.M.; Cone, J.W.; Hendriks, W.H.

    2015-01-01

    The aim of this study was to quantify the fatty acid (FA) content and composition of forages commonly fed to dairy animals in the tropics. Twelve forage species, namely, Trifolium alexandrinum, Cichorium intybus, Hordeum vulgare L., Medicago sativa, Avena sativa, Pennisetum purpureum Setaria anceps,

  18. Dworshak Reservoir Investigations: Trout, Bass and Forage Species, 1987 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Statler, David P.

    1988-05-01

    Dworshak Dam and Reservoir is a Corps of Engineers facility located on the North Fork Clearwater River 3.2 km upstream from the Mainstem Clearwater confluence. Since initial filling in 1971, conversion of 87 km of river habitat to a 6644 hectare impoundment has had a profound influence on resident fisheries. The Nez Perce Tribe and the Idaho Department of Fish and Game (IDFG) entered into separate intergovernmental agreements with the Bonneville Power Administration in a cooperative effort to study these impacts. The kokanee Oncorhynchus nerka assessment is included in the IDFG agreement, and is not addressed in this report. This project pertains primarily to rainbow trout Salmo gairdneri, smallmouth bass (Micropterus dolomieui), and forage species. For the period November 1987 through February 1988, an estimated 4339 angler-hours were expended to catch 430 rainbow trout. An estimated 20 bull trout Salvelinus confluentus, 4 smallmouth bass, and 4 suckers Catostomus spp. were also caught. Catch rates were generally poor through the period, at .091 fish per hour for all species combined (excluding kokanee). Shasta strain hatchery rainbow trout were dominant in the creel, comprising 53.9 percent of the catch, although this strain was last planted in the reservoir in June 1986. Bank anglers caught a higher percentage (93.5 percent) of the total catch of Shasta strain rainbows than Kamloops strain rainbows (33.3 percent). 11 refs., 4 figs., 6 tabs.

  19. Invasive clonal plant species have a greater root-foraging plasticity than non-invasive ones.

    Science.gov (United States)

    Keser, Lidewij H; Dawson, Wayne; Song, Yao-Bin; Yu, Fei-Hai; Fischer, Markus; Dong, Ming; van Kleunen, Mark

    2014-03-01

    Clonality is frequently positively correlated with plant invasiveness, but which aspects of clonality make some clonal species more invasive than others is not known. Due to their spreading growth form, clonal plants are likely to experience spatial heterogeneity in nutrient availability. Plasticity in allocation of biomass to clonal growth organs and roots may allow these plants to forage for high-nutrient patches. We investigated whether this foraging response is stronger in species that have become invasive than in species that have not. We used six confamilial pairs of native European clonal plant species differing in invasion success in the USA. We grew all species in large pots under homogeneous or heterogeneous nutrient conditions in a greenhouse, and compared their nutrient-foraging response and performance. Neither invasive nor non-invasive species showed significant foraging responses to heterogeneity in clonal growth organ biomass or in aboveground biomass of clonal offspring. Invasive species had, however, a greater positive foraging response in terms of root and belowground biomass than non-invasive species. Invasive species also produced more total biomass. Our results suggest that the ability for strong root foraging is among the characteristics promoting invasiveness in clonal plants.

  20. Effects of habitat composition and landscape structure on worker foraging distances of five bumble bee species.

    Science.gov (United States)

    Redhead, John W; Dreier, Stephanie; Bourke, Andrew F G; Heard, Matthew S; Jordan, William C; Sumner, Seirian; Wang, Jinliang; Carvell, Claire

    2016-04-01

    Bumble bees (Bombus spp.) are important pollinators of both crops and wildflowers. Their contribution to this essential ecosystem service has been threatened over recent decades by changes in land use, which have led to declines in their populations. In order to design effective conservation measures, it is important to understand the effects of variation in landscape composition and structure on the foraging activities of worker bumble bees. This is because the viability of individual colonies is likely to be affected by the trade-off between the energetic costs of foraging over greater distances and the potential gains from access to additional resources. We used field surveys, molecular genetics, and fine resolution remote sensing to estimate the locations of wild bumble bee nests and to infer foraging distances across a 20-km² agricultural landscape in southern England, UK. We investigated five species, including the rare B. ruderatus and ecologically similar but widespread B. hortorum. We compared worker foraging distances between species and examined how variation in landscape composition and structure affected foraging distances at the colony level. Mean worker foraging distances differed significantly between species. Bombus terrestris, B. lapidarius, and B. ruderatus exhibited significantly greater mean foraging distances (551, 536, and 501 m, respectively) than B. hortorum and B. pascuorum (336 and 272 m, respectively). There was wide variation in worker foraging distances between colonies of the same species, which was in turn strongly influenced by the amount and spatial configuration of available foraging habitats. Shorter foraging distances were found for colonies where the local landscape had high coverage and low fragmentation of semi-natural vegetation, including managed agri-environmental field margins. The strength of relationships between different landscape variables and foraging distance varied between species, for example the strongest

  1. Spatial management of marine resources can enhance the recovery of predators and avoid local depletion of forage fish

    DEFF Research Database (Denmark)

    Eero, Margit; Vinther, Morten; Haslob, Holger;

    2012-01-01

    fish, i.e., sprat and herring, is historic low in this area, which in combination with increasing cod stock results in locally high predation mortality of forage fish and cannibalism of cod. In line with low prey availability, body weight and nutritional condition of cod drastically declined...

  2. Spatial management of marine resources can enhance the recovery of predators and avoid local depletion of forage fish

    DEFF Research Database (Denmark)

    Eero, Margit; Vinther, Morten; Haslob, Holger

    2012-01-01

    fish, i.e., sprat and herring, is historic low in this area, which in combination with increasing cod stock results in locally high predation mortality of forage fish and cannibalism of cod. In line with low prey availability, body weight and nutritional condition of cod drastically declined...

  3. Digesting or swimming? Integration of the postprandial metabolism, behavior and locomotion in a frequently foraging fish.

    Science.gov (United States)

    Nie, Li-Juan; Cao, Zhen-Dong; Fu, Shi-Jian

    2017-02-01

    Fish that are active foragers usually perform routine activities while digesting their food; thus, their postprandial swimming capacity and related behavior adjustments might be ecologically important. To test whether digestion affect swimming performance and the relationships of digestion with metabolism and behavior in an active forager, we investigated the postprandial metabolic response, spontaneous swimming activities, critical swimming speed (Ucrit), and fast-start escape performance of both fasted and digesting (3h after feeding to satiation) juvenile rose bitterling (Rhodeus ocellatus). Feeding to satiation elicited a 50% increase in the oxygen consumption rate, which peaked at 3h after feeding and returned to the prefeeding state after another 3h. However, approximately 50% and 90% of individuals resumed feeding behavior at 2 and 3h postfeeding, respectively, although the meal size varied substantially. Digestion showed no effect on either steady swimming performance as suggested by the Ucrit or unsteady swimming performance indicated by the maximum linear velocity in fast-start escape movement. However, digesting fish showed more spontaneous activity as indicated by the longer total distance traveled, mainly through an increased percentage of time spent moving (PTM). A further analysis found that fasting individuals with high swimming speed were more inclined to increase their PTM during digestive processes. The present study suggests that as an active forager With a small meal size and hence limited postprandial physiological and morphological changes, the swimming performance of rose bitterling is maintained during digestion, which might be crucial for its active foraging mode and anti-predation strategy. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Food searching behaviour of a Lepidoptera pest species is modulated by the foraging gene polymorphism.

    Science.gov (United States)

    Chardonnet, Floriane; Capdevielle-Dulac, Claire; Chouquet, Bastien; Joly, Nicolas; Harry, Myriam; Le Ru, Bruno; Silvain, Jean-François; Kaiser, Laure

    2014-10-01

    The extent of damage to crop plants from pest insects depends on the foraging behaviour of the insect's feeding stage. Little is known, however, about the genetic and molecular bases of foraging behaviour in phytophagous pest insects. The foraging gene (for), a candidate gene encoding a PKG-I, has an evolutionarily conserved function in feeding strategies. Until now, for had never been studied in Lepidoptera, which includes major pest species. The cereal stem borer Sesamia nonagrioides is therefore a relevant species within this order with which to study conservation of and polymorphism in the for gene, and its role in foraging - a behavioural trait that is directly associated with plant injuries. Full sequencing of for cDNA in S. nonagrioides revealed a high degree of conservation with other insect taxa. Activation of PKG by a cGMP analogue increased larval foraging activity, measured by how frequently larvae moved between food patches in an actimeter. We found one non-synonymous allelic variation in a natural population that defined two allelic variants. These variants presented significantly different levels of foraging activity, and the behaviour was positively correlated to gene expression levels. Our results show that for gene function is conserved in this species of Lepidoptera, and describe an original case of a single nucleotide polymorphism associated with foraging behaviour variation in a pest insect. By illustrating how variation in this single gene can predict phenotype, this work opens new perspectives into the evolutionary context of insect adaptation to plants, as well as pest management.

  5. Sensory quality criteria for five fish species

    DEFF Research Database (Denmark)

    Warm, Karin; Nielsen, Jette; Hyldig, Grethe;

    2000-01-01

    Sensory profiling has been used to develop one sensory vocabulary for five fish species: cod (Gadus morhua), saithe (Pollachius virens), rainbow trout (Salmo gardineri), herring (Clupea harengus) and flounder (Platichthys flessus). A nine- member trained panel assessed 18 samples with variation...... variation and by presenting references, panel discussions and interpreting plots from multivariate data analysis. The developed profile can be used as a sensory wheel for these species, and with minor changes it may be adapted to similar species...

  6. Topographic variables improve climate models of forage species abundance in the northeastern United States

    Science.gov (United States)

    Species distribution modeling has most commonly been applied to presence-only data and to woody species, but detailed predicted abundance maps for forage species would be of great value for agricultural management and land use planning. We used field data from 107 farms across the northeastern Unite...

  7. Habitat simplification affects nuclear-follower foraging association among stream fishes

    Directory of Open Access Journals (Sweden)

    Fabrício Barreto Teresa

    Full Text Available Nuclear-follower interaction is a particular kind of interspecific foraging association that includes a nuclear species, which dig in or inspect the bottom, and follower species, which access the food items made available by the nuclear. In this study we examined the effect of habitat structure on nuclear-follower relationship in a stream of Bodoquena Plateau, Central-West Brazil. Foraging associations were registered while snorkeling in 24 observation sessions, totaling six hours in unaltered and altered sites. Overall, 272 nuclear-follower associations were registered, having four species acting as nuclear and seven as followers. The dominant nuclear species were different in each site. Prochilodus lineatus was the main nuclear species in the altered site and Leporinus macrocephalus in the unaltered site. The richness of follower species was similar between sites, however, follower species abundance per interaction were significantly higher in the unaltered site than in the altered site. These differences seem to be a consequence of the alterations in assemblage composition and feeding behavior of the nuclear species that presumably are affected by different substrate composition and food availability between the structurally distinct areas.

  8. A foraging cost of migration for a partially migratory cyprinid fish

    DEFF Research Database (Denmark)

    Chapman, Ben B; Eriksen, Anders; Baktoft, Henrik

    2013-01-01

    Rutilus rutilus, which migrates from shallow lakes to streams during winter. By sampling fish from stream and lake habitats in the autumn and spring and measuring their stomach fullness and diet composition, we tested if migrating roach pay a cost of reduced foraging when migrating. Resident fish had......Migration has evolved as a strategy to maximise individual fitness in response to seasonally changing ecological and environmental conditions. However, migration can also incur costs, and quantifying these costs can provide important clues to the ultimate ecological forces that underpin migratory...... behaviour. A key emerging model to explain migration in many systems posits that migration is driven by seasonal changes to a predation/growth potential (p/g) trade-off that a wide range of animals face. In this study we assess a key assumption of this model for a common cyprinid partial migrant, the roach...

  9. Disruption of foraging by a dominant invasive species to decrease its competitive ability.

    Science.gov (United States)

    Westermann, Fabian Ludwig; Suckling, David Maxwell; Lester, Philip John

    2014-01-01

    Invasive species are a major threat to biodiversity when dominant within their newly established habitat. The globally distributed Argentine ant Linepithema humile has been reported to break the trade-off between interference and exploitative competition, achieve high population densities, and overpower nests of many endemic ant species. We have used the sensitivity of the Argentine ant to the synthetic trail pheromone (Z)-9-hexadecanal to investigate species interactions for the first time. We predicted that disrupting Argentine ant trail following behaviour would reduce their competitive ability and create an opportunity for three other resident species to increase their foraging success. Argentine ant success in the control was reduced with increasing pheromone concentration, as predicted, but interactions varied among competing resident species. These behavioural variations provide an explanation for observed differences in foraging success of the competing resident species and how much each of these individual competitors can increase their foraging if the competitive ability of the dominant invader is decreased. The mechanism for the observed increase in resource acquisition of resident species appears to be a decrease in aggressive behaviour displayed by the Argentine ant, which may create an opportunity for other resident species to forage more successfully. Our demonstration of species interactions with trail pheromone disruption is the first known case of reduced dominance under a pheromone treatment in ants.

  10. Disruption of foraging by a dominant invasive species to decrease its competitive ability.

    Directory of Open Access Journals (Sweden)

    Fabian Ludwig Westermann

    Full Text Available Invasive species are a major threat to biodiversity when dominant within their newly established habitat. The globally distributed Argentine ant Linepithema humile has been reported to break the trade-off between interference and exploitative competition, achieve high population densities, and overpower nests of many endemic ant species. We have used the sensitivity of the Argentine ant to the synthetic trail pheromone (Z-9-hexadecanal to investigate species interactions for the first time. We predicted that disrupting Argentine ant trail following behaviour would reduce their competitive ability and create an opportunity for three other resident species to increase their foraging success. Argentine ant success in the control was reduced with increasing pheromone concentration, as predicted, but interactions varied among competing resident species. These behavioural variations provide an explanation for observed differences in foraging success of the competing resident species and how much each of these individual competitors can increase their foraging if the competitive ability of the dominant invader is decreased. The mechanism for the observed increase in resource acquisition of resident species appears to be a decrease in aggressive behaviour displayed by the Argentine ant, which may create an opportunity for other resident species to forage more successfully. Our demonstration of species interactions with trail pheromone disruption is the first known case of reduced dominance under a pheromone treatment in ants.

  11. Disruption of Foraging by a Dominant Invasive Species to Decrease Its Competitive Ability

    Science.gov (United States)

    Westermann, Fabian Ludwig; Suckling, David Maxwell; Lester, Philip John

    2014-01-01

    Invasive species are a major threat to biodiversity when dominant within their newly established habitat. The globally distributed Argentine ant Linepithema humile has been reported to break the trade-off between interference and exploitative competition, achieve high population densities, and overpower nests of many endemic ant species. We have used the sensitivity of the Argentine ant to the synthetic trail pheromone (Z)-9-hexadecanal to investigate species interactions for the first time. We predicted that disrupting Argentine ant trail following behaviour would reduce their competitive ability and create an opportunity for three other resident species to increase their foraging success. Argentine ant success in the control was reduced with increasing pheromone concentration, as predicted, but interactions varied among competing resident species. These behavioural variations provide an explanation for observed differences in foraging success of the competing resident species and how much each of these individual competitors can increase their foraging if the competitive ability of the dominant invader is decreased. The mechanism for the observed increase in resource acquisition of resident species appears to be a decrease in aggressive behaviour displayed by the Argentine ant, which may create an opportunity for other resident species to forage more successfully. Our demonstration of species interactions with trail pheromone disruption is the first known case of reduced dominance under a pheromone treatment in ants. PMID:24594633

  12. Fisheries oceanography of northern pelagic fish species

    DEFF Research Database (Denmark)

    Tsoukali, Stavroula

    of the species they consume now and increased availability of new species. In addition, there will likely be economic impacts on the local fishing communities. How species respond to climate change is a field of research that receives great attention because the responses will affect the management of fisheries...... range that maximizes survival among different species, but the sensitivity of egg development rate in a degree of temperature increase is similar among the 32 species and populations I analysed. I also found that adults spawn at temperature conditions that are generally close to the egg preferences...... seasons, at lower latitudes, are able to produce 10 times more eggs during their life time than species than have a limited spawning season. This may reflect the more un-predictable environmental conditions at lower latitudes. People are also familiar with the words "climate change" and "warming...

  13. The Relationships between Morphological Characteristics and Foraging Behavior in Four Selected Species of Shorebirds and Water Birds Utilizing Tropical Mudflats.

    Science.gov (United States)

    Norazlimi, Nor Atiqah; Ramli, Rosli

    2015-01-01

    A study was conducted to investigate the relationship between the physical morphology of shorebirds and water birds (i.e., Lesser adjutant (Leptoptilos javanicus), Common redshank (Tringa totanus), Whimbrel (Numenius phaeopus), and Little heron (Butorides striata)) and their foraging behavior in the mudflats area of Selangor, Peninsular Malaysia, from August 2013 to July 2014 by using direct observation techniques (using binoculars and a video recorder). The actively foraging bird species were watched, and their foraging activities were recorded for at least 30 seconds for up to a maximum of five minutes. A Spearman Rank Correlation highlighted a significant relationship between bill size and foraging time (R = 0.443, p birds (mm) and species (H = 15.96, p = 0.0012). Three foraging techniques were recorded: pause-travel, visual-feeding, and tactile-hunting. Thus, morphological characteristics of bird do influence their foraging behavior and strategies used when foraging.

  14. Forage fish interactions: A symposium on creating the tools for ecosystem-based management of marine resources

    DEFF Research Database (Denmark)

    Peck, M.A.; Neuenfeldt, Stefan; Essington, V.M.

    2014-01-01

    Forage fish (FF) have a unique position within marine foodwebs and the development of sustainable harvest strategies for FF will be a critical step in advancing and implementing the broader, ecosystem-based management of marine systems. In all, 70 scientists from 16 nations gathered for a symposium...

  15. Forage Fish Interactions: a symposium on "Creating the tools for ecosystem-based management of marine resources

    NARCIS (Netherlands)

    Peck, M.A.; Neuenfeldt, S.; Essington, T.E.; Dickey-Collas, M.

    2014-01-01

    Forage fish (FF) have a unique position within marine foodwebs and the development of sustainable harvest strategies for FF will be a critical step in advancing and implementing the broader, ecosystem-based management of marine systems. In all, 70 scientists from 16 nations gathered for a symposium

  16. Individual diet variation in a marine fish assemblage: Optimal Foraging Theory, Niche Variation Hypothesis and functional identity

    Science.gov (United States)

    Cachera, M.; Ernande, B.; Villanueva, M. C.; Lefebvre, S.

    2017-02-01

    Individual diet variation (i.e. diet variation among individuals) impacts intra- and inter-specific interactions. Investigating its sources and relationship with species trophic niche organization is important for understanding community structure and dynamics. Individual diet variation may increase with intra-specific phenotypic (or "individual state") variation and habitat variability, according to Optimal Foraging Theory (OFT), and with species trophic niche width, according to the Niche Variation Hypothesis (NVH). OFT proposes "proximate sources" of individual diet variation such as variations in habitat or size whereas NVH relies on "ultimate sources" related to the competitive balance between intra- and inter-specific competitions. The latter implies as a corollary that species trophic niche overlap, taken as inter-specific competition measure, decreases as species niche width and individual niche variation increase. We tested the complementary predictions of OFT and NVH in a marine fish assemblage using stomach content data and associated trophic niche metrics. The NVH predictions were tested between species of the assemblage and decomposed into a between- and a within-functional group component to assess the potential influence of species' ecological function. For most species, individual diet variation and niche overlap were consistently larger than expected. Individual diet variation increased with intra-specific variability in individual state and habitat, as expected from OFT. It also increased with species niche width but in compliance with the null expectation, thus not supporting the NVH. In contrast, species niche overlap increased significantly less than null expectation with both species niche width and individual diet variation, supporting NVH corollary. The between- and within-functional group components of the NVH relationships were consistent with those between species at the assemblage level. Changing the number of prey categories used to

  17. Quality of the forage apparently consumed by beef calves in natural grassland under fertilization and oversown with cool season forage species

    Directory of Open Access Journals (Sweden)

    Denise Adelaide Gomes Elejalde

    2012-06-01

    Full Text Available The objective of this study was to evaluate the chemical composition of the forage apparently consumed by steers in a natural grassland on region of Campanha, in Rio Grande do Sul, Brazil, subjected or not to different inputs: NP - natural pasture without inputs; FNP - fertilized natural pasture and INP - improved natural grassland with fertilization and over-seeded with cultivated winter species. Three Angus steers testers and a variable number of regulator animals per experimental unit were utilized in order to maintain 13 kg of DM/100 kg of live weight (LW as forage allowance. One time at each season, hand plucking samples were performed along the daily grazing time simulating forage harvested by the animals. The collected samples after drying and grind were submitted to chemical analysis to determine the forage quality. Except in winter and spring, the values of neutral detergent fiber were higher than the critical value of 550 g/kg of DM, which could limit forage intake, demonstrating that the values of forage on offer provided (15.6; 13.7; 13.5; 15.8 kg of DM/100 kg of LW/day in summer, autumn, winter and spring, respectively were not restrictive to intake. The oversowing of winter cultivated species or fertilization positively alter the degradable fiber content. The seasons had marked influence on the chemical composition of forage apparently consumed; positively increasing some fractions of forage chemical composition in the seasons in which native or cultivated winter species increased their participation. The forage chemical composition is the determining factor in animal performance in natural pasture.

  18. Paternity testing a non-linkage based marker assisted selection scheme for outbred forage species

    Science.gov (United States)

    In many major perennial forage species, genomic tools and infrastructure development has advanced enough that their utilization in marker assisted selection (MAS) can be cheaply explored. This paper presents a paternity testing MAS in diploid red clover (Trifolium pratense L.). Utilizing individual ...

  19. Yield and soil carbon sequestration in grazed pastures sown with two or five forage species

    Science.gov (United States)

    Increasing plant species richness is often associated with an increase in productivity and associated ecosystem services such as soil C sequestration. In this paper we report on a nine-year experiment to evaluate the relative forage production and C sequestration potential of grazed pastures sown to...

  20. Abundance of sardine fish species in Bangladesh

    Directory of Open Access Journals (Sweden)

    Roy Bikram Jit

    2012-06-01

    Full Text Available The study was conducted during January, 2012 to December 2012 in the sardine fisheries which is occurred both in artisanal and industrial fishing sector in the marine water of the Bay of Bengal of Bangladesh region. During this study period the total landing amounts by weight of sardines were 7352.99 MT, among these 23.76% (1747.22 MT was exploited by the artisanal mechanized boats and 76.24% (5605.77 MT captured through different industrial fishing trawlers and contributed 17.51% of the total marine fish production by commercial fish trawlers during the study period. 4 sardine species have been recorded from our marine territory. Among them, 2 sardine species are highly abundant, Sardinella fimbriata total production volumes was 5495.79 MT (74.74% contributed 1747.22MT (31.79% from the artisanal and 3748.57MT (68.21% from the industrial sector and Dussumieria acuta production amounts was 1857.20MT (25.26% contributed only from the industrial fishing sector.Species wise contribution shows that S. fimbriata contributed 100% in the artisanal sector and in the industrial fishing S. fimbriata contributed 66.87% and D. acuta contributed the rest 33.13%. The distribution of the S. fimbriata is within 10-20 meters depth and abundance was observed in the southern part of the South patches and South of south patches (N: 210.09// -22, E: 920.04/-07 to N: 200.45/-25, E: 920.18/-56 and 10-50m depth in onshore and off shore areas in the north-west to north-east of Middle ground (Kohinoor point -N: 210.36/.23, E: 900.06/.43 to N: 210.18/.18, E 910.17/.57. The distribution of the D. acuta is within 40-60 m. depth and abundance was observed in the north-west to north-east of Middle ground areas (Kohinoor point - N: 210.36/.23, E: 900.06/.43 to N: 210.18/.18, E 910.17/.57 and south-west to south-east of Middle ground (Kohinoor point- N: 200-17/.29, E: 900.15/.21 to N: 200.29/.56, E: 910.24/.22 in the Bay of Bengal of Bangladesh region. The peak capture season of

  1. Turtle cleaners: reef fishes foraging on epibionts of sea turtles in the tropical Southwestern Atlantic, with a summary of this association type

    Directory of Open Access Journals (Sweden)

    Cristina Sazima

    2010-03-01

    Full Text Available In the present study we record several instances of reef fish species foraging on epibionts of sea turtles (cleaning symbiosis at the oceanic islands of Fernando de Noronha Archipelago and near a shipwreck, both off the coast of Pernambuco State, northeast Brazil. Nine reef fish species and three turtle species involved in cleaning are herein recorded. Besides our records, a summary of the literature on this association type is presented. Postures adopted by turtles during the interaction are related to the habits of associated fishes. Feeding associations between fishes and turtles seem a localized, albeit common, phenomenon.No presente estudo registramos diversos episódios de peixes recifais alimentando-se de epibiontes sobre o corpo de tartarugas marinhas (simbiose de limpeza nas ilhas oceânicas do arquipélago de Fernando de Noronha e próximo a um naufrágio na costa de Pernambuco, nordeste do Brasil. Nove espécies de peixes recifais e três espécies de tartarugas envolvidas nas associações são aqui registradas. Além de nossos registros, apresentamos também um resumo da literatura sobre o tema. As posturas adotadas pelas tartarugas durante as interações estão relacionadas com os hábitos dos peixes associados. Associações alimentares entre peixes e tartarugas podem ser consideradas como um fenômeno local, embora comum.

  2. Medusivorous fishes, a review

    NARCIS (Netherlands)

    Ates, R.M.L.

    1988-01-01

    A preliminary review is presented of fish species having consumed pelagic Cnidaria (Scyphozoa and Hydrozoa) as well as Ctenophora. Quantitative data are scarce. Knowledge of morphological and physiological adaptations of fishes foraging on gelatinous plankton is almost non-existent. Many fish specie

  3. Medusivorous fishes, a review

    OpenAIRE

    Ates, R.M.L.

    1988-01-01

    A preliminary review is presented of fish species having consumed pelagic Cnidaria (Scyphozoa and Hydrozoa) as well as Ctenophora. Quantitative data are scarce. Knowledge of morphological and physiological adaptations of fishes foraging on gelatinous plankton is almost non-existent. Many fish species consume medusae and some reasons to suspect that there are even more that do so, are discussed.

  4. Vast assembly of vocal marine mammals from diverse species on fish spawning ground.

    Science.gov (United States)

    Wang, Delin; Garcia, Heriberto; Huang, Wei; Tran, Duong D; Jain, Ankita D; Yi, Dong Hoon; Gong, Zheng; Jech, J Michael; Godø, Olav Rune; Makris, Nicholas C; Ratilal, Purnima

    2016-03-17

    Observing marine mammal (MM) populations continuously in time and space over the immense ocean areas they inhabit is challenging but essential for gathering an unambiguous record of their distribution, as well as understanding their behaviour and interaction with prey species. Here we use passive ocean acoustic waveguide remote sensing (POAWRS) in an important North Atlantic feeding ground to instantaneously detect, localize and classify MM vocalizations from diverse species over an approximately 100,000 km(2) region. More than eight species of vocal MMs are found to spatially converge on fish spawning areas containing massive densely populated herring shoals at night-time and diffuse herring distributions during daytime. We find the vocal MMs divide the enormous fish prey field into species-specific foraging areas with varying degrees of spatial overlap, maintained for at least two weeks of the herring spawning period. The recorded vocalization rates are diel (24 h)-dependent for all MM species, with some significantly more vocal at night and others more vocal during the day. The four key baleen whale species of the region: fin, humpback, blue and minke have vocalization rate trends that are highly correlated to trends in fish shoaling density and to each other over the diel cycle. These results reveal the temporospatial dynamics of combined multi-species MM foraging activities in the vicinity of an extensive fish prey field that forms a massive ecological hotspot, and would be unattainable with conventional methodologies. Understanding MM behaviour and distributions is essential for management of marine ecosystems and for accessing anthropogenic impacts on these protected marine species.

  5. Grey seals use anthropogenic signals from acoustic tags to locate fish: evidence from a simulated foraging task.

    Science.gov (United States)

    Stansbury, Amanda L; Götz, Thomas; Deecke, Volker B; Janik, Vincent M

    2015-01-07

    Anthropogenic noise can have negative effects on animal behaviour and physiology. However, noise is often introduced systematically and potentially provides information for navigation or prey detection. Here, we show that grey seals (Halichoerus grypus) learn to use sounds from acoustic fish tags as an indicator of food location. In 20 randomized trials each, 10 grey seals individually explored 20 foraging boxes, with one box containing a tagged fish, one containing an untagged fish and all other boxes being empty. The tagged box was found after significantly fewer non-tag box visits across trials, and seals revisited boxes containing the tag more often than any other box. The time and number of boxes needed to find both fish decreased significantly throughout consecutive trials. Two additional controls were conducted to investigate the role of the acoustic signal: (i) tags were placed in one box, with no fish present in any boxes and (ii) additional pieces of fish, inaccessible to the seal, were placed in the previously empty 18 boxes, making possible alternative chemosensory cues less reliable. During these controls, the acoustically tagged box was generally found significantly faster than the control box. Our results show that animals learn to use information provided by anthropogenic signals to enhance foraging success.

  6. Electric signals and species recognition in the wave-type gymnotiform fish Apteronotus leptorhynchus.

    Science.gov (United States)

    Fugère, V; Krahe, R

    2010-01-15

    Gymnotiformes are South American weakly electric fish that produce weak electric organ discharges (EOD) for orientation, foraging and communication purposes. It has been shown that EOD properties vary widely across species and could thus be used as species recognition signals. We measured and quantified the electric signals of various species using a landmark-based approach. Using discriminant function analysis to verify whether these signals are species specific based on different signal parameters, we found that the EOD waveform is a more specific cue than EOD frequency, which shows large overlap across species. Using Apteronotus leptorhynchus as a focal species, we then performed a series of playback experiments using stimuli of different species (varying in frequency, waveform, or both). In an experiment with restrained fish, we found, in contrast to what we predicted, that the choice of stimulus waveform did not affect the production of communication signals. In an experiment with free-swimming fish, the animals spent more time near the playback electrodes and produced more communication signals when the stimuli were within their conspecific frequency range. Waveform again had no measurable effect. The production of communication signals correlated with the frequency difference between the stimulus and the fish's own EOD, but approach behavior did not.

  7. Grey seals use anthropogenic signals from acoustic tags to locate fish : evidence from a simulated foraging task

    OpenAIRE

    Stansbury, Amanda; Gotz, Thomas; Deecke, Volker Bernt; Janik, Vincent M.

    2014-01-01

    This study was conducted under Home Office licence number 60/3303 Anthropogenic noise can have negative effects on animal behaviour and physiology. However, noise is often introduced systematically and potentially provides information for navigation or prey detection. Here, we show that grey seals (Halichoerus grypus) learn to use sounds from acoustic fish tags as an indicator of food location. In 20 randomized trials each, 10 grey seals individually explored 20 foraging boxes, with one bo...

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

  10. Fish Springs National Wildlife Refuge Odonata species checklist 2007

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Species check list for Odonata (damselflies and dragonflies) located at Fish Springs National Wildlife Refuge in August, 2007. Scientific name and common name is...

  11. 分类觅食人工鱼群算法%Assorted foraging artificial fish swarm algorithm

    Institute of Scientific and Technical Information of China (English)

    李辉

    2016-01-01

    针对人工鱼群算法搜索速度和搜索精度不高,且对高维问题寻优能力较差等缺点,提出了一种改进的人工鱼群算法——分类觅食人工鱼群算法(Assorted Foraging Artificial Fish Swarm Algorithm-AFAFSA).该算法对执行觅食行为的个体分类进行更新,既保持种群的多样性又通过觅食行为加快算法的搜索速度,同时加入禁忌的思想帮助算法跳出局部最优,提高算法的性能.通过一系列的测试试验,发现改进算法在收敛速度和精度方面都有了明显的提高,对于高维问题有也具有较好的寻优能力.

  12. Alien fish species in reservoir systems in Turkey: a review

    Directory of Open Access Journals (Sweden)

    Deniz Innal

    2012-12-01

    Full Text Available Turkey’s natural river systems have been anthropogenically altered in the past century. Native fish communities of river systems have comeunder increasing pressure from water engineering projects, pollution, overfishing and the movements of alien fish species. Introduction ofalien fishes is one of the main threats to the survival and genetic integrity of native fishes around the world. In Turkey, alien freshwater fish are continuing to increase in number of species, abundance, and distribution. The present paper reviews fish stocking studies in Turkey’s reservoirs.

  13. Forage fish quality: seasonal lipid dynamics of herring (Clupea harengus L.) and sprat (Sprattus sprattus L.) in the Baltic Sea

    DEFF Research Database (Denmark)

    Røjbek, Maria; Tomkiewicz, Jonna; Jacobsen, Charlotte

    2013-01-01

    This study investigates lipid content and fatty acid composition of two important forage fish, sprat (Sprattus sprattus) and herring (Clupea harengus) in the Baltic Sea ecosystem. Seasonal variation in lipids was studied during three periods following the annual reproductive cycle considering...... potential differences relating to fish size, sex, and reproductive status. The isopod Saduria entomon, being at times an important prey for predatory fish, was included for comparison. In both sprat and herring, lipid content and absolute contents of essential polyunsaturated fatty acids (PUFAs) varied...... seasonally with high levelstowards the end of the annual zooplankton production cycle, succeeded by a decline. Lipid content and fatty acid composition differed significantly between sprat and herring. Sprat lipid content was higher than herring, increasing with fish size and characterized by large...

  14. Detection of Vibrio Species Isolated from Ornamental Guppy Fish in Kashan, Isfahan, Iran Fish culturing Pounds

    National Research Council Canada - National Science Library

    Samira Kiani; Nafiseh Sadat Naghavi; Alireza Nazari

    2016-01-01

    .... Materials and methods: In the present study Vibrio species isolated from ornamental guppy fish in Kashan, Isfahan, Iran fish ponds and were detected according to molecular detection and genetic alignment...

  15. Root foraging for Patchy Phosphorus of Plant Species with Contrasting Foraging Strategy - Role of Roots and Mycorrhiza

    Science.gov (United States)

    Felderer, B.; Robinson, B. H.; Jansa, J.; Vontobel, P.; Frossard, E.; Schulin, R.

    2009-04-01

    Plant nutrients are distributed heterogeneously in soil. Thus the nutrient distribution together with nutrient availability, temporal and spatial development of roots determine nutrient uptake by the plants. Plants have developed several strategies to cope with the patchy nutrient distribution. Preferential root development within nutrient-enriched patches is a prominent response to heterogeneous nutrient distribution. This capacity to precisely allocate roots is called morphological plasticity and is highly variable between plant species. Another strategy is the increased nutrient uptake per unit of root surface in the nutrient-rich patches as compared to root zones outside such patches, so-called physiological plasticity . Additionally, enhanced nutrient uptake from nutrient-rich patches might be supported by increased production of mycorrhizal extraradical hyphae. We refer to this phenomenon as plastic response of the mycorrhiza-plant association. Relative importance for nutrient acquisition of these responses to heterogeneous nutrient distribution might vary between plant species. However, quantitative data are very rare. We will investigate nutrient acquisition and root development over time in sandy substrate with heterogeneous phosphorus (P) distribution of two model plant species with different nutrient foraging strategies (Lotus corniculatus, Trifolium arvense). These plant species are characterized by high and low morphological plasticity, respectively (according to results of preliminary experiments). We follow three main goals in a single mesocosm experiment, where P is to be homogeneously or patchily distributed in a sandy substrate: 1. - Imaging of root architecture of Lotus corniculatus and Trifolium arvense on a time line. 2. - Assessment of the physiological plasticity of Lotus corniculatus and Trifolium arvense 3. - Determination of the plasticity of mycorrhiza-plant association of Lotus corniculatus and Trifolium arvense associated with either of

  16. Fish species recognition using computer vision and a neural network

    NARCIS (Netherlands)

    Storbeck, F.; Daan, B.

    2001-01-01

    A system is described to recognize fish species by computer vision and a neural network program. The vision system measures a number of features of fish as seen by a camera perpendicular to a conveyor belt. The features used here are the widths and heights at various locations along the fish. First

  17. Forage yield and nutritive value of Elephant grass, Italian ryegrass and spontaneous growing species mixed with forage peanut or red clover

    Directory of Open Access Journals (Sweden)

    Michelle Schalemberg Diehl

    2014-10-01

    Full Text Available The objective of this research was to evaluate of three grazing systems (GS with elephant grass (EG, Italian ryegrass (IR + spontaneous growing species (SGS; EG + IR + SGS + forage peanut (FP; and EG + IR + SGS + red clover (RC, during the winter and summer periods in rotational grazing with dairy cattle. Experimental design was completely randomized with three treatments, two replicates with repeated measures. Lactating Holstein cows receiving 1% BW-daily feed supplement with concentrate were used in the evaluation. Eight grazing cycles were performed during the experimental period. The values of pre forage mass and stocking rate were 2.52, 2.60 and 2.99 t ha-1 and 2.64, 2.77 and 3.14 animal unit ha-1, respectively for GS. Samples of forage were collected by hand-plucking technique to analyze the crude protein (CP, neutral detergent fiber (NDF, in situ dry matter digestibility (ISDMD, in situ organic matter digestibility (ISOMD of forage present between rows of elephant grass, in the rows of elephant grass and the legumes. Higher value of CP, ISOMD and lower of NDF were observed for the grazing systems mixed with legumes forage.

  18. Hatching asynchrony vs. foraging efficiency: the response to food availability in specialist vs. generalist tit species

    Science.gov (United States)

    Barrientos, R.; Bueno-Enciso, J.; Sanz, J. J.

    2016-01-01

    Breeding mistiming is increasingly frequent in several ecosystems in the face of current climate change. Species belonging to higher trophic levels must employ mechanisms to reduce it. One of these mechanisms is hatching asynchrony, with the eggs in a clutch hatching over a period of several days. Some authors have suggested it to be adaptive when food is unpredictable. However, these birds can also suffer associated costs. We tested whether a species with higher foraging efficiency avoid hatching asynchrony compared to its sister species. We studied hatching asynchrony and nestling provisioning in relation to food availability in sympatric populations of blue and great tits. For the first time, we show that sister species respond to food availability with different strategies. Blue tit feeding rates readily responded to the abundance of their main prey, and also reduced the impact of nestling size hierarchy on mean nestling weight, consequently increasing fledging rate. Our results suggest that levels of hatching asynchrony seem to be influenced by species-specific life history traits, as generalist foragers rely less on it. They also highlight the importance of multi-species approaches when studying the response of organisms to environmental unpredictability. PMID:27892941

  19. 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.

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

    Science.gov (United States)

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

    2016-04-01

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

  1. A model for habitat selection and species distribution derived from central place foraging theory.

    Science.gov (United States)

    Olsson, Ola; Bolin, Arvid

    2014-06-01

    We have developed a habitat selection model based on central place foraging theory. An individual's decision to include a patch in its habitat depends on the marginal fitness contribution of that patch, which is characterized by its quality and distance to the central place. The essence of the model we have developed is a fitness isocline which is a function of patch quality and travel time to the patch. It has two parameters: the maximum travel distance to a patch of infinite quality and a coefficient that appropriately scales quality by travel time. Patches falling below the isocline will have positive marginal fitness values and should be included in the habitat. The maximum travel distance depends on the availability and quality of patches, as well as on the forager's life history, whereas the scaling parameter mostly depends on life history properties. Using the model, we derived a landscape quality metric (which can be thought of as a connectivity measure) that sums the values of available habitat in the landscape around a central place. We then fitted the two parameters to foraging data on breeding white storks (Ciconia ciconia) and estimated landscape quality, which correlated strongly with reproductive success. Landscape quality was then calculated for a larger region where re-introduction of the species is currently going on in order to demonstrate how this model can also be regarded as a species distribution model. In conclusion, we have built a general habitat selection model for central place foragers and a novel way of estimating landscape quality based on a behaviorally scaled connectivity metric.

  2. Medusivorous fishes, a review

    NARCIS (Netherlands)

    Ates, R.M.L.

    1988-01-01

    A preliminary review is presented of fish species having consumed pelagic Cnidaria (Scyphozoa and Hydrozoa) as well as Ctenophora. Quantitative data are scarce. Knowledge of morphological and physiological adaptations of fishes foraging on gelatinous plankton is almost non-existent. Many fish

  3. The Relationships between Morphological Characteristics and Foraging Behavior in Four Selected Species of Shorebirds and Water Birds Utilizing Tropical Mudflats

    Directory of Open Access Journals (Sweden)

    Nor Atiqah Norazlimi

    2015-01-01

    Full Text Available A study was conducted to investigate the relationship between the physical morphology of shorebirds and water birds (i.e., Lesser adjutant (Leptoptilos javanicus, Common redshank (Tringa totanus, Whimbrel (Numenius phaeopus, and Little heron (Butorides striata and their foraging behavior in the mudflats area of Selangor, Peninsular Malaysia, from August 2013 to July 2014 by using direct observation techniques (using binoculars and a video recorder. The actively foraging bird species were watched, and their foraging activities were recorded for at least 30 seconds for up to a maximum of five minutes. A Spearman Rank Correlation highlighted a significant relationship between bill size and foraging time (R=0.443, p<0.05, bill size and prey size (R=-0.052, p<0.05, bill size and probing depth (R=0.42, p=0.003, and leg length and water/mud depth (R=0.706, p<0.005. A Kruskal-Wallis Analysis showed a significant difference between average estimates of real probing depth of the birds (mm and species (H=15.96, p=0.0012. Three foraging techniques were recorded: pause-travel, visual-feeding, and tactile-hunting. Thus, morphological characteristics of bird do influence their foraging behavior and strategies used when foraging.

  4. Detection of Vibrio Species Isolated from Ornamental Guppy Fish in Kashan, Isfahan, Iran Fish culturing Pounds

    OpenAIRE

    Samira Kiani; Nafiseh Sadat Naghavi; Alireza Nazari

    2016-01-01

    Introduction: Gram-negative bacteria are the most pathogenic bacteria for marine organisms including ornamental fish. Materials and methods: In the present study Vibrio species isolated from ornamental guppy fish in Kashan, Isfahan, Iran fish ponds and were detected according to molecular detection and genetic alignment. Liver, kidney, skin, brain and gill samples were taken from ornamental guppy fish in Kashan, Isfahan, Iran. Samples were cultured on enriched culture media and purificati...

  5. Past and present fish species recorded in the estuarine Lake Ichkeul ...

    African Journals Online (AJOL)

    Past and present fish species recorded in the estuarine Lake Ichkeul, northern Tunisia. ... appear to be the principal causes for the decline in fish abundance and diversity. Keywords: estuarine fish, freshwater fish, marine fish, salinity, seasonal ...

  6. Identification And Study Of Fish Species In Karkheh River (Iran

    Directory of Open Access Journals (Sweden)

    Khoshnood Zahra

    2014-10-01

    Full Text Available For the investigation of fish from Karkheh River, sampling was performed in a six month period from August 2014 to January 2015. All sampled fish were measured for biometrical values (length and weight. General results of the sampling and identification of the fish showed the presence of 14 species from four fish families of Cyprinidae, Mugilidae, Siluridae and Macrostomidae, out of which the Cyprinidae family were the most frequent of the sampled fish. The most significant abundance belongs to Cyprinus carpio. The fish sampled in the present study were: Liza abu, Ctenopharyngodon idella, Barbel sp., Cyprinion macrostomum, Barbus sharpeyi, Hypophthalmichthys molitrix, Barbus esocinus, Barbus barbulus, Barbus luteus, Barbus grypus, Cyprinus carpio, Silurus triostegus, Mastacembelus circumcinctus and Capoeta trutta. Shannon Index results showed that the fish biodiversity in the studyed area followed a uniform path and additionally that the considered area at the studied period has good fish biodiversity.

  7. POPs and stable isotopes in bird and forage fish tissues - Persistent organic pollutant levels in juvenile salmonids, forage fish and their avian predators from Puget Sound and the outer WA coast

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This project is examining contaminant loads of fish prey species of a resident marine bird (Rhinoceros Auklet) breeding in inland waters (Puget Sound) and in the...

  8. Ethnobotanical study of forage/fodder plant species in and around the semi-arid Awash National Park, Ethiopia

    Institute of Scientific and Technical Information of China (English)

    Tinsae Bahru; Zemede Asfaw; Sebsebe Demissew

    2014-01-01

    We undertook ethnobotanical study of forage/fodder plant species used by the Afar and Oromo (Kereyu and Ittu) Nations in and around the semi-arid Awash National Park (ANP), Ethiopia. The study aimed at investigating and documenting indigenous knowledge (IK) on forage/fodder plant species and threats to their survival. Ninety-six in-formants between 20 and 80 years old were selected using prior informa-tion. Data were collected using semi-structured interview, guided field walk, discussion and field observation. Preference ranking, Jaccard’s coefficient of similarity and priority ranking were used for data analysis. One hundred twenty-six forage/fodder species of 90 genera and 43 fami-lies were collected in the study area. More than 88%of the species were reported with their vernacular names, where 68% were reported by the Afar Nation and 70%by the Oromo Nation. Family Poaceae was repre-sented by 25 species (20%), followed by Fabaceae 18 (14%). Preference ranking for the most preferred forage grasses as perceived by key infor-mants revealed that Chrysopogon plumulosus was the most important forage/fodder species. Overgrazing was the major threat in the study area, scoring 22%.

  9. The Natural Diet of Five Cyprinid Fish Species

    Directory of Open Access Journals (Sweden)

    Marina Piria

    2005-03-01

    There are very few published papers on the biology of these fish species, and even less on their natural feeding in the open waters. Although these fish species economically less important, is play an important role in the open waters ecological niche. One of the most important factors for the ecological niche is food web. Therefore, the purpose of this paper was to revise the research and written documentation collected on the feeding of chub, bleak, spirlin, barbel and stream barbel in Croatia and in Europe. More important results on recent research done for each fish species in various waters in Europe are also presented in this paper.

  10. Effects of tree species richness and composition on moose winter browsing damage and foraging selectivity: an experimental study.

    Science.gov (United States)

    Milligan, Harriet T; Koricheva, Julia

    2013-07-01

    The optimal foraging theory, the nutrient balance hypothesis, and the plant association theories predict that foraging decisions and resulting tree damage by large mammalian browsers may be influenced by the species richness and species composition of forest stands. This may lead to either associational susceptibility (increased damage on a focal plant in a mixed stand) or associational resistance (reduced damage in a mixed stand). Better understanding of the mechanisms and the relative importance of tree species richness and composition effects on foraging by mammalian browsers is needed to support sustainable management of forests and mammal populations. However, existing knowledge of forest diversity effects on foraging by large mammalian browsers comes largely from observational studies while experimental evidence is limited. We analysed winter browsing by moose (Alces alces L.) in a long-term, large-scale experiment in Finland, which represents a tree species richness gradient from monocultures to 2-, 3- and 5-species mixtures composed of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L.), Siberian larch (Larix sibirica Ledeb.), silver birch (Betula pendula Roth.) and black alder (Alnus glutinosa L.). The intensity of browsing per plot increased with tree species richness while browsing selectivity decreased with tree species being targeted more equally in species-rich mixtures. Tree species composition of a plot was also an important determinant of intensity of browsing. The greatest browsing occurred in plots containing preferred species (pine and birch) while intermediate preference species (larch and alder) experienced associational susceptibility when growing with pine and birch compared with their monocultures or mixtures without pine and birch. In contrast, we found no evidence of associational resistance; the presence of a least preferred species (spruce) in a mixture had no significant effect on moose browsing on other tree species. We

  11. Endangered fish species of the world - a review

    Directory of Open Access Journals (Sweden)

    Radu Hărşan

    2008-12-01

    Full Text Available The present paper summarizes a large part of the endangered and critically endangered fish species of the world. The list was constructed using the comprehensive IUCN Red List of Threatened Species (available in December 2008 and the well elaborated FISHBASE (available on the official website, in 2008 for taxonomy and accepted scientific names of the species. To these two important sources, many scientific papers and communications were added when recent and useful reports were found. However, there is a long way from the fish species list of this review to the world?s complete list of endangered and critically endangered fish species. In our list were not included subspecies, populations, varieties, or species having a debatable taxonomic status. The scope of this review was not to inventorize all the fishes included in these two categories, but to make possible drawing some general conclusions regarding most important possible causes of fish species extinction and to make suggestions concerning fish species conservation possibilities through aquaculture.

  12. Characterization and identification of Pediococcus species isolated from forage crops and their application for silage preparation.

    Science.gov (United States)

    Cai, Y; Kumai, S; Ogawa, M; Benno, Y; Nakase, T

    1999-07-01

    Pediococcus species isolated from forage crops were characterized, and their application to silage preparation was studied. Most isolates were distributed on forage crops at low frequency. These isolates could be divided into three (A, B, and C) groups by their sugar fermentation patterns. Strains LA 3, LA 35, and LS 5 are representative isolates from groups A, B, and C, respectively. Strains LA 3 and LA 35 had intragroup DNA homology values above 93.6%, showing that they belong to the species Pediococcus acidilactici. Strain LS 5 belonged to Pediococcus pentosaceus on the basis of DNA-DNA relatedness. All three of these strains and strain SL 1 (Lactobacillus casei, isolated from a commercial inoculant) were used as additives to alfalfa and Italian ryegrass silage preparation at two temperatures (25 and 48 degrees C). When stored at 25 degrees C, all of the inoculated silages were well preserved and exhibited significantly (P ammonia-nitrogen content, gas production, and dry matter loss and significantly (P < 0.05) higher lactate content than the control, but silages inoculated with LS 5 and SL 1 were of poor quality. P. acidilactici LA 3 and LA 35 are considered suitable as potential silage inoculants.

  13. Native Freshwater Fish and Mussel Species Richness

    Data.gov (United States)

    U.S. Environmental Protection Agency — These data represent predicted current distributions of all native freshwater fish and freshwater mussels in the Middle-Atlantic region. The data are available for...

  14. GRASS SPECIES FROM C-4 CARBON FIXATION GROUP: POLISH EXPERIMENT WITH A NOVEL ENERGY AND FORAGE PURPOSES CROP

    Directory of Open Access Journals (Sweden)

    Włodzimierz Majtkowski

    2010-02-01

    Full Text Available Experiment was conducted during four years 2003-2006. Materials used were three genus grass species of C-4 photosynthesis: Andropogon gerardi Vitman, Panicum virgatum L. and Miscanthus sacchariflorus (Maxim. Hack. Plants were planted at spring 1998. Agrotechnical part of experiment was conducted in Botanical Garden of Plant Breeding Acclimatization Institute in Bydgoszcz and analytical part in Department of Animal Nutrition and Feed Management, Faculty of Animal Breeding and Biology of University of Technology and Life Science in Bydgoszcz. Forage from grass C-4 photosynthesis were material of good ensilage suitability. High structural carbohydrates (NDF, ADF contents in tested forage dry matter suggest ensilage at early phases of plant development. Above results suggest to possibility of usage of forage from grass C-4 carbon fixation group for animal feeding purposes. C-4 grass forage should be recognized as a supplementary source of green matter in periods of insufficient access to traditional silage sources.

  15. Modeling of Valued Fish Species in River Networks

    Science.gov (United States)

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

  16. Study on Microelements of Ten Consumed Fish Species by NAA

    Institute of Scientific and Technical Information of China (English)

    YUAN; Guo-jun; XIAO; Cai-jin; JIN; Xiang-chun; YANG; Wei; ZHANG; Gui-ying; WANG; Ping-sheng; NI; Bang-fa

    2012-01-01

    <正>As the improvement of the living standard, people are more and more concerned about the safety of food currently. The fish is healthy food with more protein but less fat. We bought ten species of fish from the market, which are often eaten by Chinese, and analyzed the microelement of them by NAA.

  17. Climate induced increases in species richness of marine fishes

    NARCIS (Netherlands)

    Hiddink, J.G.; Hofstede, ter R.

    2008-01-01

    Climate change has been predicted to lead to changes in local and regional species richness through species extinctions and latitudinal ranges shifts. Here, we show that species richness of fish in the North Sea, a group of ecological and socio-economical importance, has increased over a 22-year per

  18. Consequences of seasonal variation in reservoir water level for predatory fishes: linking visual foraging and prey densities

    Science.gov (United States)

    Klobucar, Stephen L.; Budy, Phaedra

    2016-01-01

    In reservoirs, seasonal drawdown can alter the physical environment and may influence predatory fish performance. We investigated the performance of lake trout (Salvelinus namaycush) in a western reservoir by coupling field measurements with visual foraging and bioenergetic models at four distinct states (early summer, mid-summer, late summer, and fall). The models suggested that lake trout prey, juvenile kokanee (Oncorhynchus nerka), are limited seasonally by suitable temperature and dissolved oxygen. Accordingly, prey densities were greatest in late summer when reservoir volume was lowest and fish were concentrated by stratification. Prey encounter rates (up to 68 fish·day−1) and predator consumption are also predicted to be greatest during late summer. However, our models suggested that turbidity negatively correlates with prey detection and consumption across reservoir states. Under the most turbid conditions, lake trout did not meet physiological demands; however, during less turbid periods, predator consumption reached maximum bioenergetic efficiency. Overall, our findings demonstrate that rapid reservoir fluctuations and associated abiotic conditions can influence predator–prey interactions, and our models describe the potential impacts of water level fluctuation on valuable sport fishes.

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

    Science.gov (United States)

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

    2012-01-01

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

  20. DEVELOPMENT OF TECHNOLOGY FOR FISH CANNED PATE'S COD-FISH SPECIES

    OpenAIRE

    A. A. Efremova; L. K. Kuranova; O. A. Nikolaenko

    2014-01-01

    Summary. Fish and seafood play an important role in a balanced diet. The most reliable method of preservation is the production of canned fish. Cod fishery considered traditional objects of the North Basin, which catches in recent years stored at a consistently high level. They are represented, mainly cod, haddock, pollack, whiting. Lately there has been a tendency to increase yield loaves (polar bib). The aim of this work - the development of technology - canned pate's cod fish species with ...

  1. Model for Predicting Passage of Invasive Fish Species Through Culverts

    Science.gov (United States)

    Neary, V.

    2010-12-01

    Conservation efforts to promote or inhibit fish passage include the application of simple fish passage models to determine whether an open channel flow allows passage of a given fish species. Derivations of simple fish passage models for uniform and nonuniform flow conditions are presented. For uniform flow conditions, a model equation is developed that predicts the mean-current velocity threshold in a fishway, or velocity barrier, which causes exhaustion at a given maximum distance of ascent. The derivation of a simple expression for this exhaustion-threshold (ET) passage model is presented using kinematic principles coupled with fatigue curves for threatened and endangered fish species. Mean current velocities at or above the threshold predict failure to pass. Mean current velocities below the threshold predict successful passage. The model is therefore intuitive and easily applied to predict passage or exclusion. The ET model’s simplicity comes with limitations, however, including its application only to uniform flow, which is rarely found in the field. This limitation is addressed by deriving a model that accounts for nonuniform conditions, including backwater profiles and drawdown curves. Comparison of these models with experimental data from volitional swimming studies of fish indicates reasonable performance, but limitations are still present due to the difficulty in predicting fish behavior and passage strategies that can vary among individuals and different fish species.

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

    Directory of Open Access Journals (Sweden)

    Anna Hubackova

    2014-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  4. The composition of mixed-species foraging flocks of birds in Kruger National Park, South Africa

    Directory of Open Access Journals (Sweden)

    Guy Hausler

    2016-03-01

    Full Text Available Mixed-species foraging flocks (MSFFs of birds can be defined as aggregations of more than two species that actively initiate and continue their association while foraging, without being drawn to a single resource. MSFFs have been well documented for terrestrial habitats globally, but rarely in southern Africa. This study describes the composition of MSFFs in two habitat types (Acacia and Combretum within the southern Kruger National Park, South Africa during the late dry season. Thirty-one MSFFs were recorded in each of the two habitat types, with 1251 individuals of 74 different species being observed. We found that compared to Combretum, (mean: 10.7 ± 5.2 s.d. Acacia had significantly more individuals per MSFFs (mean: 21.5 ± 12.6 s.d. and more species per MSFF (Acacia mean: 8.7 ± 3.5 s.d.; Combretum mean: 5.9 ± 1.7 s.d.. The mean number of individuals per species per 31 MSFFs was 9.3 (± 4.5 s.d. and 7.6 (± 5.6 s.d. in the Acacia and Combretum habitat types respectively. The most frequently occurring species in both habitat types was the Fork-tailed Drongo (Dicrurus adsimilis. There was a significant association between certain species pairs in both habitats. Future studies in this area could be done to investigate the reasons behind the differences in MSFF sizes and species numbers between habitats. The season during which this study was performed excluded all summer migrants and a similar investigation in the wet season may reveal a different MSFF composition.Conservation implications: Understanding the dynamics and compositions of MSFFs, could form a valuable component of avian biodiversity monitoring both in and outside of protected areas. Within a given area, changes in the composition and behaviour of MSFFs over time could potentially be used as early indicator of threats to biodiversity.Keywords: avian; habitat; savanna

  5. Shape and Texture Based Classification of Fish Species

    DEFF Research Database (Denmark)

    Larsen, Rasmus; Ólafsdóttir, Hildur; Ersbøll, Bjarne Kjær

    2009-01-01

    In this paper we conduct a case study of ¯sh species classi- fication based on shape and texture. We consider three fish species: cod, haddock, and whiting. We derive shape and texture features from an appearance model of a set of training data. The fish in the training images were manual outlined...... to discriminate between the fish types, as well as conducted a preliminary classfication. In a linear discrimant analysis based on the two best combined modes of variation we obtain a resubstitution rate of 76 %...

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

    Directory of Open Access Journals (Sweden)

    Manfred Schartl

    2014-02-01

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

  7. 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

  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. Habitat use pattern of three species of egrets in a small coastal ...

    African Journals Online (AJOL)

    ... in Ghana to determine the extent of utilisation of non-fish resources by these species, ... whereas those in marginal water forage on fish and possibly aquatic invertebrates. ... Keywords: arthropods, Egretta, fish, human-wildlife conflict, niche ...

  10. Swimming strategy and body plan of the world’s largest fish: implications for foraging efficiency and thermoregulation

    Directory of Open Access Journals (Sweden)

    Mark eMeekan

    2015-09-01

    Full Text Available The largest animals in the oceans eat prey that are orders of magnitude smaller than themselves, implying strong selection for cost-effective foraging to meet their energy demands. Whale sharks (Rhincodon typus may be especially challenged by warm seas that elevate their metabolism and contain sparse prey resources. Using a combination of biologging and satellite tagging, we show that whale sharks use four strategies to save energy and improve foraging efficiency: 1 fixed, low power swimming, 2 constant low speed swimming, 3 gliding and 4 asymmetrical diving. These strategies increase foraging efficiency by 22 – 32% relative to swimming horizontally and resolve the energy-budget paradox of whale sharks. However, sharks in the open ocean must access food resources that reside in relatively cold waters (up to 20oC cooler than the surface at depths of 250-500 m during the daytime, where long, slow gliding descents, continuous ram ventilation of the gills and filter-feeding could rapidly cool the circulating blood and body tissues. We suggest that whale sharks may overcome this problem through their large size and a specialized body plan that isolates highly vascularized red muscle on the dorsal surface, allowing heat to be retained near the centre of the body within a massive core of white muscle. This could allow a warm-adapted species to maintain enhanced function of organs and sensory systems while exploiting food resources in deep, cool water.

  11. Gulf Watch Alaska Forage Fish Component: Fish Morph data in Prince William Sound, Alaska 2012-2015

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are part of the Gulf Watch Alaska (GWA) long term monitoring program, pelagic monitoring component. This dataset contains fish morph data from summer...

  12. The bottlenose dolphin Tursiops truncatus foraging around a fish farm: Effects of prey abundance on dolphins’ behavior

    Directory of Open Access Journals (Sweden)

    Bruno Díaz LÓPEZ

    2009-08-01

    Full Text Available The extent to which prey abundance influences both bottlenose dolphin foraging behavior and group size in the presence of human activities has not previously been studied. The primary aim of this study was to identify and quantify how wild bottlenose dolphins respond, individually and as groups, to the relative abundance of prey around a fish farm. Detailed views of dolphins’ behavior were obtained by focal following individual animals whilst simultaneously collecting surface and underwater behavioral data. A total of 2150 dive intervals were analyzed, corresponding to 342 focal samples, lasting over 34 hours. Bottlenose dolphins remained submerged for a mean duration of 46.4 seconds and a maximum of 249 seconds. This study provides the first quantified data on bottlenose dolphin diving behavior in a marine fin-fish farm area. This study’s results indicate that within a fish farm area used intensively by bottlenose dolphins for feeding, dolphins did not modify dive duration. Additionally, underwater observations confirmed that dolphins find it easier to exploit a concentrated food source and it appears that hunting tactic and not group size plays an important role during feeding activities. Thus, bottlenose dolphins appear capable of modifying their hunting tactics according to the abundance of prey. When top predators display behavioral responses to activities not directed at them, the task of studying all possible effects of human activities can become even more challenging [Current Zoology 55(4: 243–248, 2009].

  13. How Do Grass Species, Season and Ensiling Influence Mycotoxin Content in Forage?

    Directory of Open Access Journals (Sweden)

    Adam Nawrath

    2013-11-01

    Full Text Available Mycotoxins are secondary metabolites produced by fungal species that have harmful effects on mammals. The aim of this study was to assess the content of mycotoxins in fresh-cut material of selected forage grass species both during and at the end of the growing season. We further assessed mycotoxin content in subsequently produced first-cutting silages with respect to the species used in this study: Lolium perenne (cv. Kentaur, Festulolium pabulare (cv. Felina, Festulolium braunii (cv. Perseus, and mixtures of these species with Festuca rubra (cv. Gondolin or Poa pratensis (Slezanka. The mycotoxins deoxynivalenol, zearalenone and T-2 toxin were mainly detected in the fresh-cut grass material, while fumonisin and aflatoxin contents were below the detection limits. July and October were the most risky periods for mycotoxins to occur. During the cold temperatures in November and December, the occurrence of mycotoxins in fresh-cut material declined. Although June was a period with low incidence of mycotoxins in green silage, contents of deoxynivalenol and zearalenone in silages from the first cutting exceeded by several times those determined in their biomass collected directly from the field. Moreover, we observed that use of preservatives or inoculants did not prevent mycotoxin production.

  14. How do grass species, season and ensiling influence mycotoxin content in forage?

    Science.gov (United States)

    Skladanka, Jiri; Adam, Vojtech; Dolezal, Petr; Nedelnik, Jan; Kizek, Rene; Linduskova, Hana; Mejia, Jhonny Edison Alba; Nawrath, Adam

    2013-11-12

    Mycotoxins are secondary metabolites produced by fungal species that have harmful effects on mammals. The aim of this study was to assess the content of mycotoxins in fresh-cut material of selected forage grass species both during and at the end of the growing season. We further assessed mycotoxin content in subsequently produced first-cutting silages with respect to the species used in this study: Lolium perenne (cv. Kentaur), Festulolium pabulare (cv. Felina), Festulolium braunii (cv. Perseus), and mixtures of these species with Festuca rubra (cv. Gondolin) or Poa pratensis (Slezanka). The mycotoxins deoxynivalenol, zearalenone and T-2 toxin were mainly detected in the fresh-cut grass material, while fumonisin and aflatoxin contents were below the detection limits. July and October were the most risky periods for mycotoxins to occur. During the cold temperatures in November and December, the occurrence of mycotoxins in fresh-cut material declined. Although June was a period with low incidence of mycotoxins in green silage, contents of deoxynivalenol and zearalenone in silages from the first cutting exceeded by several times those determined in their biomass collected directly from the field. Moreover, we observed that use of preservatives or inoculants did not prevent mycotoxin production.

  15. ASSESSMENT OF THE DEVELOPMЕNT OF POND FORAGE BASE WHEN REARING CARP (CYPRINUS CARPIO CARPIO FISH SEEDS AT FISH FARM «MERKURIY»

    Directory of Open Access Journals (Sweden)

    B. Grishin

    2015-09-01

    Full Text Available Purpose. To assess the development of main components of natural forage base in nursery ponds during the period of rearing the carp fish seeds in monoculture. Methodology. Hydrobiological (bacterioplankton, phytoplankton, zooplankton, zoobenthos and hydrochemical samples have been collected and processes according to generally accepted methods. Findings. Qualitative and quantitative parameters of the development of bacterio-, phyto-, zooplankton and zoobenthos in nursery ponds have been studied when rearing young-of-the-year Lubin few scale carp, Antoninsko-Zozulenets carp and their reciprocal crosses in monoculture (50 thousand fish/ha. General water mineralization in ponds was 292.7–315.7 mg/dm3 and according to O.A. Alekin’s classification, pond water belonged to hydrocarbonate class of calcium group. Water pH was 7.4–7.5. Permanganate values were 12.5–14.9 mgO/dm3. On average, average ammonium nitrogen content, nitrite nitrogen and nitrate nitrogen, mineral phosphorus, total iron did not exceed normative values. Qualitative and quantitative parameters of phyto-, bacterio-, zooplankton of nursery ponds have been studied. The seasonal development of phytoplankton was within 15.96–20.88 mg/dm3 with the predominance of Chlorococcales in the floristic spectrum. The development of bacterioplankton was within 5.08–5.81 mg/dm3. Zooplankton was dominated by cladoceran-copepod complex with average seasonal values of 5.27–17.20 g/m3. Zoobenthos was formed of Diptera larvae (Chironomidae and Chaoboridae with average seasonal biomasses of 0.51–1.8 g/m2. According to saprobic parameters, pond water belonged to β-mesosabrobic zone and corresponded to the water quality class II (“clean enough” category. Fish productivity of nursery ponds was within 617.2–815.2 kg/ha; output of carp young-of-the-year was within 39.82–43.56%, mean weight of young-of-the-year was 31.0–39.3 g. Originality. For the first time we carried out a

  16. The influence of chemoreception on the foraging behaviour of two species of sandpiper, calidris alba and calidris alpina

    Science.gov (United States)

    Van Heezik, Y. M.; Gerritsen, A. F. C.; Swennen, C.

    This study is concerned with the ability of two wader species, the sanderling, Calidris alba and the dunlin, C. alpina to determine the presence of prey in a sediment by using their sense of taste, and whether they use this information while foraging for prey hidden in the sediment. Preference tests were designed in which the birds were presented with a choice of 2 jars filled with sand from 3 possible combination pairs: (1) "food" and "no taste", (2) "food" and "taste", and (3) "taste" and "no taste". Preferences were measured as the relative amount of time spent foraging in each jar of each pair. Significantly more time was spent on "taste" than on "no taste" for the "taste" and "no taste" combination. More time was spent on "taste" than on "no taste" when each was paired with "food" for 3 out of 4 situations. Foraging technique on "taste" was observed to be more purposeful and methodical than on "no taste". Both species are shown to be able to use taste while foraging to determine whether prey is present, and can modify their foraging behaviour by persisting in a spot that gives no information on the presence of prey other than taste, and by using a different, more determined searching technique.

  17. Dworshak Reservoir Investigations: Trout, Bass and Forage Species, 1988 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Statler, David P.

    1989-07-01

    For the period March 1988 through February 1989, an estimated 154,558 angler-hours were expended to catch 20,037 rainbow trout, 3,933 smallmouth bass, and 14 bull trout. Estimated catch of other species, including cutthroat trout, whitefish, suckers, and squawfish totalled 84. Subcatchable rainbow trout (135 to 185mm) caught and released by boat anglers comprised 53% (12,770) of the total catch. An estimated 88.6% of the smallmouth bass caught were under the minimum legal size limit of 305mm and were released. Estimated harvest of smallmouth bass was 450. The highest monthly catch rate documented for all species excluding kokanee was 1.81 fish per hour during October. Severe weather conditions during February reduced effort and no fish were documented in the creel. Cumulative catch rates through the survey period for rainbow trout and smallmouth bass were .13 and .02, respectively. The lowest monthly catch rates generally occurred when fishing pressure was the highest, with fishing effort targeting on kokanee during the May through July high use periods. The Arlee strain rainbow trout was somewhat more vulnerable to boat anglers than the Shasta strain during the early post-release period. 20 refs., 16 figs., 12 tabs.

  18. Marine foraging and annual fish consumption of a south polar Skua population in the maritime Antarctic

    NARCIS (Netherlands)

    Hahn, S.M.; Ritz, M.S.; Reinhardt, K.

    2008-01-01

    Pelagic fish are an important component of Antarctic food webs but few quantitative data exist on energy transfer from fish to seabirds for the Seasonal Pack-ice Zone. We studied a local population of south polar, skuas Catharacta maccormicki during a whole breeding cycle and estimated its entire

  19. Patrones de forrajeo en dos especies de peces intermareales herbívoros de las costas de Chile: Efecto de la abundancia y composición química del alimento Foraging patterns of two species of intertidal herbivorous fishes: Effect of food abundance and chemical composition

    Directory of Open Access Journals (Sweden)

    CRISTIAN W. CACERES

    2000-06-01

    in relation to fish herbivory are: i which are the factors that determine the selection or rejection of a given algal item? and ii are herbivorous fishes capable of extracting the nutrients and energy of a macroalgal diet? In this work, we studied in two species of herbivorous intertidal fishes, Scartichthys viridis and Girella laevifrons, the patterns of food selectivity in the field and in laboratory experiments, the assimilation efficiency for different dietary algal items, and the relationship between the observed patterns and the chemical composition of the algae. The results showed that more than 90% of the diet of these organisms consisted of benthic macroalgae. In the field both species present a non-selective trophic behavior in summer and selective one in winter, characterized by the consumption of green algae in the later season. Furthermore, in the experiments of food selection both species showed a similar pattern characterized by the preference of green and red algae. The results of the assimilation experiments, indicate that Girella laevifrons presents higher values of this parameter than Scartichthys viridis, being in the former the green algae Ulva and Enteromorpha, the items that present a higher efficiency of assimilation. Finally, the results obtained suggest in this herbivorous species a strong relationship among the patterns of food selection and the relationship between food composition and digestive characteristics

  20. CAGE BREEDING OF WARM WATER FRESHWATER FISH SPECIES

    Directory of Open Access Journals (Sweden)

    Roman Safner

    2008-10-01

    Full Text Available In the 1970s, Croatia became actively involved in the contemporary trend of breeding fish in floating cages. In addition to various species of marine fishes, breeding was attempted with trout, carp, catfish, cisco and salmon. Of the above freshwater fish species, specific standards were established only for the cage breeding of rainbow trout. Cage breeding of the remaining species remained at the level of occasional attempts, with more of an experimental than a commercial character. The regular attempts to master this technique for cage breeding of warm water freshwater fish species were aimed at achieving the known benefits of such breeding, such as simplicity of implementing technological measures, easier establishment of the breeding system, simpler manipulation, the possibility of denser colonies per unit volume with a high level of production, easier adaptations to market conditions and fewer initial structural investments. Despite the many advantages, the main reasons for the lack of greater implementation of the cage breeding technology for warm water species of freshwater fish include problems in obtaining the appropriate category and quantity of healthy fry, the specificity and applicability of physical and chemical properties of the recipients and human error. In evaluating the advantages and disadvantages, the final decision on the justification of cage breeding for individual warm water freshwater species must be based on both biological and economic factors. Based on the knowledge of cage breeding acquired to date, the rule for virtually all intensive breeding systems is that it is only recommended for those species with high market demand and a high market price. The technology that demands nutrition with highly concentrated feed and other production expenditures is costly, and is therefore not profitable with less expensive fish species. Furthermore, production must be market oriented, i.e. the appropriate market research measures

  1. Following a foraging fish-finder: diel habitat use of Blainville's beaked whales revealed by echolocation.

    Directory of Open Access Journals (Sweden)

    Patricia Arranz

    Full Text Available Simultaneous high resolution sampling of predator behavior and habitat characteristics is often difficult to achieve despite its importance in understanding the foraging decisions and habitat use of predators. Here we tap into the biosonar system of Blainville's beaked whales, Mesoplodon densirostris, using sound and orientation recording tags to uncover prey-finding cues available to echolocating predators in the deep-sea. Echolocation sounds indicate where whales search and encounter prey, as well as the altitude of whales above the sea-floor and the density of organisms around them, providing a link between foraging activity and the bio-physical environment. Tagged whales (n = 9 hunted exclusively at depth, investing most of their search time either in the lower part of the deep scattering layer (DSL or near the sea-floor with little diel change. At least 43% (420/974 of recorded prey-capture attempts were performed within the benthic boundary layer despite a wide range of dive depths, and many dives included both meso- and bentho-pelagic foraging. Blainville's beaked whales only initiate searching when already deep in the descent and encounter prey suitable for capture within 2 min of the start of echolocation, suggesting that these whales are accessing prey in reliable vertical strata. Moreover, these prey resources are sufficiently dense to feed the animals in what is effectively four hours of hunting per day enabling a strategy in which long dives to exploit numerous deep-prey with low nutritional value require protracted recovery periods (average 1.5 h between dives. This apparent searching efficiency maybe aided by inhabiting steep undersea slopes with access to both the DSL and the sea-floor over small spatial scales. Aggregations of prey in these biotopes are located using biosonar-derived landmarks and represent stable and abundant resources for Blainville's beaked whales in the otherwise food-limited deep-ocean.

  2. Following a foraging fish-finder: diel habitat use of Blainville's beaked whales revealed by echolocation.

    Science.gov (United States)

    Arranz, Patricia; Aguilar de Soto, Natacha; Madsen, Peter T; Brito, Alberto; Bordes, Fernando; Johnson, Mark P

    2011-01-01

    Simultaneous high resolution sampling of predator behavior and habitat characteristics is often difficult to achieve despite its importance in understanding the foraging decisions and habitat use of predators. Here we tap into the biosonar system of Blainville's beaked whales, Mesoplodon densirostris, using sound and orientation recording tags to uncover prey-finding cues available to echolocating predators in the deep-sea. Echolocation sounds indicate where whales search and encounter prey, as well as the altitude of whales above the sea-floor and the density of organisms around them, providing a link between foraging activity and the bio-physical environment. Tagged whales (n = 9) hunted exclusively at depth, investing most of their search time either in the lower part of the deep scattering layer (DSL) or near the sea-floor with little diel change. At least 43% (420/974) of recorded prey-capture attempts were performed within the benthic boundary layer despite a wide range of dive depths, and many dives included both meso- and bentho-pelagic foraging. Blainville's beaked whales only initiate searching when already deep in the descent and encounter prey suitable for capture within 2 min of the start of echolocation, suggesting that these whales are accessing prey in reliable vertical strata. Moreover, these prey resources are sufficiently dense to feed the animals in what is effectively four hours of hunting per day enabling a strategy in which long dives to exploit numerous deep-prey with low nutritional value require protracted recovery periods (average 1.5 h) between dives. This apparent searching efficiency maybe aided by inhabiting steep undersea slopes with access to both the DSL and the sea-floor over small spatial scales. Aggregations of prey in these biotopes are located using biosonar-derived landmarks and represent stable and abundant resources for Blainville's beaked whales in the otherwise food-limited deep-ocean.

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

    Science.gov (United States)

    Raibaut, André; Combes, Claude; Benoit, Françoise

    1998-06-01

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

  4. Nonindigenous Aquatic Species Database Marine Fishes

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The Nonindigenous Aquatic Species Database (NAS) information resource is an established central repository for spatially referenced biogeographic accounts of...

  5. Female social response to male sexual harassment in poeciliid fish: a comparison of six species.

    Science.gov (United States)

    Dadda, Marco

    2015-01-01

    Sexual harassment is common among poeciliid fish. In some fishes, males show a high frequency of sneak copulation; such sexual activity is costly to the females in terms of foraging efficiency. In mosquitofish (Gambusia holbrooki), when males are present, the distance between females tends to decrease, and this behavior has been interpreted as an adaptive strategy to dilute the costs of male sexual activity. In this study, the tendency to reduce distance in the presence of a male has been investigated in females of six poeciliid species (Girardinus metallicus, Girardinus falcatus, G. holbrooki, Poecilia reticulata, Xiphophorus hellerii, and Xiphophorus mayae) that exhibit different male mating strategies and different levels of sexual activity. Results revealed large interspecific differences in the pattern of female aggregation. Females of species with a high frequency of sneak copulations tended to reduce their social distance in the presence of a male. By contrast, species that rely mainly on courtship showed little or no variation in social distance. The proportion of sneak copulations predicts the degree of variation in female social response, but the amount of total sexual activity does not, suggesting that the change in females' social distance when a male is present may indeed serve to reduce the costs of male sexual harassment.

  6. Female social response to male sexual harassment in poeciliid fish: A comparison of six species

    Directory of Open Access Journals (Sweden)

    Marco eDadda

    2015-09-01

    Full Text Available Sexual harassment is common among poeciliid fish. In some fishes, males show a high frequency of sneak copulation; such sexual activity is costly to the females in terms of foraging efficiency. In mosquitofish (Gambusia holbrooki, when males are present, the distance between females tends to decrease, and this behavior has been interpreted as an adaptive strategy to dilute the costs of male sexual activity. In this study, the tendency to reduce distance in the presence of a male has been investigated in females of 6 poeciliid species (Girardinus metallicus, Girardinus falcatus, Gambusia holbrooki, Poecilia reticulata, Xiphophorus hellerii and Xiphophorus mayae that exhibit different male mating strategies and different levels of sexual activity. Results revealed large interspecific differences in the pattern of female aggregation. Females of species with a high frequency of sneak copulations tended to reduce their social distance in the presence of a male. By contrast, species that rely mainly on courtship showed little or no variation in social distance. The proportion of sneak copulations predicts the degree of variation in female social response, but the amount of total sexual activity does not, suggesting that the change in females’ social distance when a male is present may indeed serve to reduce the costs of male sexual harassment.

  7. Seasonal plankton-fish interactions: light regime, prey phenology, and herring foraging.

    Science.gov (United States)

    Varpe, Øystein; Fiksen, Øyvind

    2010-02-01

    When prey and predator are seasonal migrants, encounters depend on migration phenologies and environmental constraints on predation. Here we investigate the relative contribution of seasonality in irradiance and prey abundance in shaping the rapid seasonal body condition increase of a migrating predator searching visually for its prey: the Norwegian spring-spawning herring, Clupea harengus, feeding on the copepod Calanus finmarchicus. Two main seasonal pulses of prey are available to herring: (1) the parent generation of C. finmarchicus, with peak abundance in March-April, which appear too early to cause the main increase in herring condition; and (2) the abundant offspring generation of C. finmarchicus, with peak abundance in June-July, too late to explain the main increase in body condition. However, a mechanistic model of ingestion rate, including both solar irradiance and prey abundance, predicted seasonal food intake in good accordance with observed herring body condition. This suggests that the seasonality in herring foraging and energy storage is closely linked to the return of longer days in spring, and less dependent on a match or mismatch with seasonal peaks in abundance of their zooplankton prey. Consequently, light related constraints on foraging may make visually searching predators at high latitudes resilient to changes and fluctuations in prey phenology and abundance, but vulnerable to changes in the light regime, such as water clarity.

  8. Feeding Relationships of Dominant Fish Species in the Visayan Sea

    Directory of Open Access Journals (Sweden)

    Annie Trixie Mequila

    2007-06-01

    Full Text Available This study examines the diet composition of 15 fish species belonging to 11 families in the Visayan Sea. A total of 50 prey items were identified from 323 stomachs examined. Cluster analysis was used to assess similarities in the composition of prey items in individuals of similar sizes but of different species, and in individuals of the same species but of different size categories. The results showed high similarity among individuals of the same species and low similarity between different species of similar size categories. Two major clusters were formed, showing generalist feeding (high niche widths and trophic segregation (low food niche overlap. These suggest that food resources in the Visayan Sea are not limited and that a wide range of habitats is available to the fish community.

  9. Euclinostomum heterostomum (Rudolphi, 1809 Metacercarial Infection in Three Osphronemid Fish Specieshree Osphronemid Fish Species

    Directory of Open Access Journals (Sweden)

    Watchariya PURIVIROJKUL

    2013-02-01

    Full Text Available Trematode metacercariae, Euclinostomum heterostomum from naturally infested osphronemid fish in Thailand were investigated. Encysted musculature was observed in the case of heavy infestation in all three osphronemid fish species, Trichopsis vittata, Betta splendens and Betta imbellis. Infected fish showed tubercle-like thickened areas of different size, 0.2 - 0.5 cm which appear on the skin. A histological study showed metacercaria were enclosed by a thin sheet of connective tissue. This is a new recorded host of E. heterostomum.

  10. Domestication of Marine Fish Species: Update and Perspectives

    Directory of Open Access Journals (Sweden)

    Fabrice Teletchea

    2015-10-01

    Full Text Available Domestication is a long and endless process during which animals become, generations after generations, more adapted to both captive conditions and humans. Compared to land animals, domestication of fish species has started recently. This implies that most farmed marine fish species have only changed slightly from their wild counterparts, and production is based partly or completely on wild inputs. In the past decades, global marine fish production has increased tremendously, particularly since the 1990s, to reach more than 2.2 million tons in 2013. Among the 100 marine fish species listed in the FAO’s database in 2013, 35 are no longer produced, and only six have a production higher than 100,000 tons. The top ten farmed marine species accounted for nearly 90% of global production. The future growth and sustainability of mariculture will depend partly on our ability to domesticate (i.e., control the life cycle in captivity of both currently farmed and new species.

  11. Contents of lead and cadmium in selected fish species consumed in Finland in 1993-1994.

    Science.gov (United States)

    Tahvonen, R; Kumpulainen, J

    1996-01-01

    The lead and cadmium contents of the main fish species consumed in Finland were determined by ETAAS after wet digestion with HNO3. Analytical quality was controlled with blanks, reference materials and blind replicates. Mean and median lead contents of domestic fish species were fish and imported canned or salted fish ranged from fish species were fish contained canned or salted fish 9-42 micrograms Cd per kg. Higher fish consumption would not increase lead or cadmium intake significantly in Finland. At present fish contributes about 4% of the average lead intake and 3% of cadmium intake.

  12. 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

  13. Effect of different forage species supplemented with two carbohydrate sources on short and medium chain fatty acids in sheep milk

    Directory of Open Access Journals (Sweden)

    G. Piredda

    2010-04-01

    Full Text Available Sixty four Sarda dairy sheep fed with diets based on fresh forage were allocated to eight groups to evaluate the effect of corn or beet pulp based supplementation on milk fatty acid composition. Four forage species were compared: annual ryegrass (RY, Lolium rigidum Gaudin, sulla (SU, Hedysarum coronarium L., burr medic (BM, Medicago polymorpha L., and garland, a daisy forb, (CH, Chrysanthemum coronarium L.. The supplements were iso-nitrogenous but differed in carbohydrate composition consisting either of 60% (DM of corn (concentrate C or 40% sugar beet pulp (concentrate BP. The supplementation was iso-energetic (500 and 530 g/d, respectively. Overall during winter period (growing stage of the forages SU and RY groups showed higher levels of atherogenicity index and C16:0. In winter period BP outperformed C for palmitic acid. In spring AI showed a trend similar to that of winter. Moreover C concentrate gave a better level of AI and myristic acid than BP. This study confirms that forage species and, to a lesser extent, carbohydrate source in the supplement markedly affect mediumchain FA profile and hence atherogenicity index in sheep milk.

  14. Long-term species, sexual and individual variations in foraging strategies of fur seals revealed by stable isotopes in whiskers.

    Directory of Open Access Journals (Sweden)

    Laëtitia Kernaléguen

    Full Text Available BACKGROUND: Individual variations in the use of the species niche are an important component of diversity in trophic interactions. A challenge in testing consistency of individual foraging strategy is the repeated collection of information on the same individuals. METHODOLOGY/PRINCIPAL FINDINGS: The foraging strategies of sympatric fur seals (Arctocephalus gazella and A. tropicalis were examined using the stable isotope signature of serially sampled whiskers. Most whiskers exhibited synchronous δ(13C and δ(15N oscillations that correspond to the seal annual movements over the long term (up to 8 years. δ(13C and δ(15N values were spread over large ranges, with differences between species, sexes and individuals. The main segregating mechanism operates at the spatial scale. Most seals favored foraging in subantarctic waters (where the Crozet Islands are located where they fed on myctophids. However, A. gazella dispersed in the Antarctic Zone and A. tropicalis more in the subtropics. Gender differences in annual time budget shape the seal movements. Males that do not perform any parental care exhibited large isotopic oscillations reflecting broad annual migrations, while isotopic values of females confined to a limited foraging range during lactation exhibited smaller changes. Limited inter-individual isotopic variations occurred in female seals and in male A. tropicalis. In contrast, male A. gazella showed large inter-individual variations, with some males migrating repeatedly to high-Antarctic waters where they fed on krill, thus meaning that individual specialization occurred over years. CONCLUSIONS/SIGNIFICANCE: Whisker isotopic signature yields unique long-term information on individual behaviour that integrates the spatial, trophic and temporal dimensions of the ecological niche. The method allows depicting the entire realized niche of the species, including some of its less well-known components such as age-, sex-, individual- and

  15. Long-Term Species, Sexual and Individual Variations in Foraging Strategies of Fur Seals Revealed by Stable Isotopes in Whiskers

    Science.gov (United States)

    Kernaléguen, Laëtitia; Cazelles, Bernard; Arnould, John P. Y.; Richard, Pierre; Guinet, Christophe; Cherel, Yves

    2012-01-01

    Background Individual variations in the use of the species niche are an important component of diversity in trophic interactions. A challenge in testing consistency of individual foraging strategy is the repeated collection of information on the same individuals. Methodology/Principal Findings The foraging strategies of sympatric fur seals (Arctocephalus gazella and A. tropicalis) were examined using the stable isotope signature of serially sampled whiskers. Most whiskers exhibited synchronous δ13C and δ15N oscillations that correspond to the seal annual movements over the long term (up to 8 years). δ13C and δ15N values were spread over large ranges, with differences between species, sexes and individuals. The main segregating mechanism operates at the spatial scale. Most seals favored foraging in subantarctic waters (where the Crozet Islands are located) where they fed on myctophids. However, A. gazella dispersed in the Antarctic Zone and A. tropicalis more in the subtropics. Gender differences in annual time budget shape the seal movements. Males that do not perform any parental care exhibited large isotopic oscillations reflecting broad annual migrations, while isotopic values of females confined to a limited foraging range during lactation exhibited smaller changes. Limited inter-individual isotopic variations occurred in female seals and in male A. tropicalis. In contrast, male A. gazella showed large inter-individual variations, with some males migrating repeatedly to high-Antarctic waters where they fed on krill, thus meaning that individual specialization occurred over years. Conclusions/Significance Whisker isotopic signature yields unique long-term information on individual behaviour that integrates the spatial, trophic and temporal dimensions of the ecological niche. The method allows depicting the entire realized niche of the species, including some of its less well-known components such as age-, sex-, individual- and migration-related changes. It

  16. DEVELOPMENT OF TECHNOLOGY FOR FISH CANNED PATE'S COD-FISH SPECIES

    Directory of Open Access Journals (Sweden)

    A. A. Efremova

    2014-01-01

    Full Text Available Summary. Fish and seafood play an important role in a balanced diet. The most reliable method of preservation is the production of canned fish. Cod fishery considered traditional objects of the North Basin, which catches in recent years stored at a consistently high level. They are represented, mainly cod, haddock, pollack, whiting. Lately there has been a tendency to increase yield loaves (polar bib. The aim of this work - the development of technology - canned pate's cod fish species with the addition of plant materials. We used the adopted research microbiological, chemical and physical methods. The weight proportion of water, lipids, protein, mineral raw determined according to State standard 7636-85. Developed a technology - canned pate's cod fish species with the addition of plant materials. Optimized formulation is set to sterilization. Experimentally determined parameters of quality canned and given comprehensive assessment nutritional value of new products, organoleptic, physico-chemical, biochemical and microbiological tests showed that canned pates of Gadidae species of fish with vegetables, meet all safety requirements and are characterized, along with excellent consumer properties, high nutritional value. Based on the results of the research complex developed technical documentation for production of canned vegetables, pates of Gadidae species.

  17. Colour forms of Amazonian cichlid fish represent reproductively isolated species.

    Science.gov (United States)

    Ready, J S; Sampaio, I; Schneider, H; Vinson, C; Dos Santos, T; Turner, G F

    2006-07-01

    Laboratory mate choice experiments have confirmed species status for cichlid fish in the African Great Lakes that differ in colour and little else. Colour differences between allopatric populations of the South American cichlid genus Apistogramma are known for many species, yet the status of such populations has not been previously tested. Analysis of the genetic relationships and mate choice characteristics of populations previously described as Apistogramma caetei from eastern Amazonia indicates genetic differentiation into at least three allopatric lineages, which also show strong prezygotic isolation through female mate choice, confirming them as Biological species. If future studies confirm that this result is indicative of a general trend, the species richness of the South American cichlid fishes may presently be seriously underestimated.

  18. Determinants of tree species preference for foraging by insectivorous birds in a novel Prosopis - Leucaena woodland in Puerto Rico: the role of foliage palatability

    Science.gov (United States)

    W. Beltran; J.M. Wunderle Jr.

    2013-01-01

    The foliage palatability hypothesis predicts that avian insectivores will preferentially forage in tree species with the greatest abundance of their arthropod prey, which in turn are associated with the tree’s foliage nutrition and palatability. We tested this hypothesis in a novel Prosopis–Leucaena woodland in Puerto Rico by determining foraging preferences of five...

  19. Chemical composition and in vitro total gas and methane production of forage species from the Mid Rift Valley grasslands of Ethiopia

    NARCIS (Netherlands)

    Bezabih, M.; Pellikaan, W.F.; Tolera, A.; Khan, N.A.; Hendriks, W.H.

    2014-01-01

    There is increasing interest in sustainable land use in the tropics to optimize animal production while also reducing methane (CH4) emissions, but information on nutritive value and CH4-emission potential of tropical forage species is limited. Samples of 24 grasses and five other forages were collec

  20. As multiple fish species in large marine ecosystems are harvested ...

    African Journals Online (AJOL)

    CMPTMAC10

    culling to increase fish available for human harvesting ... species to develop positive surplus production invari- ... Whole-ecosystem foodweb models, specifically the dynamic model ECOSIM, contain specific ... of younger animals, would unrealistically overestimate ..... sidered to have sufficient weight to have reproductive.

  1. Production of trans C18:1 and conjugated linoleic acid in continuous culture fermenters fed diets containing fish oil and sunflower oil with decreasing levels of forage.

    Science.gov (United States)

    Abughazaleh, A; Jacobson, B N

    2007-06-01

    Previously, feeding fish oil (FO) and sunflower seeds to dairy cows resulted in the greatest increases in the concentrations of vaccenic acid (VA, t11 C18:1) and conjugated linoleic acid (CLA) in milk fat. The objective of this study was to evaluate the effects of forage level in diets containing FO and sunflower oil (SFO) on the production of trans C18:1 and CLA by mixed ruminal microbes. A dual-flow continuous culture system consisting of three fermenters was used in a 3 × 3 Latin-square design. Treatments consisted of (1) 75:25 forage:concentrate (HF); (2) 50:50 forage:concentrate (MF); and (3) 25:75 forage:concentrate (LF). FO and SFO were added to each diet at 1 and 2 g/100 g dry matter (DM), respectively. The forage source was alfalfa pellets. During 10-day incubations, fermenters were fed treatment diets three times daily (140 g/day, divided equally between three feedings) as TMR diet. Effluents from the last 3 days of incubation were collected and composited for analysis. The concentration of trans C18:1 (17.20, 26.60, and 36.08 mg/g DM overflow for HF, MF, and LF treatments, respectively) increased while CLA (2.53, 2.35, and 0.81 mg/g DM overflow) decreased in a linear manner ( P effluent increased ( P effluent decreased in a linear manner ( P < 0.05) as dietary forage levels decreased. Decreasing dietary forage levels resulted in t10 C18:1 and t10c12 CLA replacing VA and c9t11 CLA, respectively, in fermenters fed FO and SFO.

  2. Legumes and forage species sole or intercropped with corn in soybean-corn succession in midwestern Brazil

    Directory of Open Access Journals (Sweden)

    Gessí Ceccon

    2013-02-01

    Full Text Available The feasibility of no-tillage in the Cerrado (Savanna-like vegetation of Brazil depends on the production of sufficient above-ground crop residue, which can be increased by corn-forage intercropping. This study evaluated how above-ground crop residue production and yields of soybean and late-season corn in a soybean-corn rotation were influenced by the following crops in the year before soybean: corn (Zea mays L. intercropped with Brachiaria (Urochloa brizantha cv. Marandu, B. decumbens cv. Basilisk, B. ruziziensis, cv. comum., Panicummaximum cv. Tanzânia, sunn hemp (Crotalaria juncea L., pigeon pea [Cajanus cajan (L. Millsp]; sole corn, forage sorghum [Sorghum bicolor (L. Moench (cv. Santa Elisa], and ruzi grass. In March 2005, corn and forage species were planted in alternate rows spaced 0.90 m apart, and sole forage species were planted in rows spaced 0.45 m apart. In October 2005, the forages were killed with glyphosate and soybean was planted. After the soybean harvest in March 2006, sole late-season corn was planted in the entire experimental area. Corn grain and stover yields were unaffected by intercropping. Above-ground crop residue was greater when corn was intercropped with Tanzania grass (10.7 Mg ha-1, Marandu (10.1 Mg ha-1, and Ruzi Grass (9.8 Mg ha-1 than when corn was not intercropped (4.0 Mg ha-1. The intercropped treatments increased the percentage of soil surface covered with crop residue. Soybean and corn grain yields were higher after sole ruzi grass and intercropped ruzi grass than after other crops. The intercropping corn with Brachiaria spp. and corn with Panicum spp. increases above-ground crop residue production and maintains nutrients in the soil without reducing late-season corn yield and the viability of no-till in the midwestern region of Brazil.

  3. Alley cropping of legumes with grasses as forages : Effect of different grass species and row spacing of gliricidia on the growth and biomass production of forages

    Directory of Open Access Journals (Sweden)

    Siti Yuhaeni

    1998-12-01

    Full Text Available A study to evaluate the effect of different grass species and row spacing of gliricidia (Gliricidia sepium on the growth and biomass production of forages in an alley cropping system was conducted in two different agroclimatical zones i.e. Bogor, located at 500 m a .s .l . with an average annual rainfall of 3,112 nun/year and Sukabumi located at 900 m a .s .l . with an average annual rainfall of 1,402 mm/year . Both locations have low N, P, and K content and the soil is classified as acidic. The experimental design used was a split plot design with 3 replicates . The main plots were different grass species i.e. king grass (Pennisetum purpureum x P. typhoides and elephant grass (P. purpureum. The sub plots were the row spacing of gliricidia at 2, 3, 4, 6 m (1 hedgerows and 4 m (2 hedgerows. The results indicated that the growth and biomass production of grasses were significantly affected (P<0 .05 by the treatments in Bogor. The highest biomass productions was obtained from the 2 m row spacing which gave the highest dry matter production of grasses (1 .65 kg/hill and gliricidia (0 .086 kg/tree . In Sukabumi the growth and biomass production of grasses and gliricidia were also significantly affected by the treatments . The highest dry matter production was obtained with 2 m row spacing (dry matter of grasses and gliricidia were 1 .12 kg/hill and 0 .026 kg/tree, respectively . The result further indicated that biomass production of forages increased with the increase in gliricidia population. The alley cropping system wich is suitable for Bogor was the 2 m row spacing of gliricidia intercropped with either king or elephant grass and for Sukabumi 2 and 4 m (2 rows of gliricidia row spacing intercropped with king or elephant grass .

  4. Experimental cultivation of a new forage species - Silphium perfoliatum L. - in the Agrobotanical Garden from Cluj-Napoca

    Directory of Open Access Journals (Sweden)

    Ioan PUIA

    1985-08-01

    Full Text Available Based on results of Niqueux (1981 Silphium perfoliatum (Asteroideae, Heliantheae germplasm preserved in our garden was used for the introduction of this newly emerging forage species in experimental cultivation. As generative reproduction proved to be allowed, plants were reproduced by rhizomes. The influence of bud number per rhizome, fertilization and the inclination of the plot on the growth dynamics and production were studied. Plots were harvested in 1983 and 1984 for silage and seed. The average production of hay in one cut was 6,7 t/ha in 1983 and 6,3 t/ha in 1984. The best plot yiealded 15,7 (1983 and 10,8 t/ha hay. Average seed yield was in 1984: 587 kg/ha, the highest yield was 1265 kg/ha. In so far as we know, this is the first introduction of the species in cultivation for economic purposes (forage or biomass in Romania.

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

    OpenAIRE

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

    2014-01-01

    A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6°C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg·h...

  6. Experimental cultivation of a new forage species - Silphium perfoliatum L. - in the Agrobotanical Garden from Cluj-Napoca

    OpenAIRE

    1985-01-01

    Based on results of Niqueux (1981) Silphium perfoliatum (Asteroideae, Heliantheae) germplasm preserved in our garden was used for the introduction of this newly emerging forage species in experimental cultivation. As generative reproduction proved to be allowed, plants were reproduced by rhizomes. The influence of bud number per rhizome, fertilization and the inclination of the plot on the growth dynamics and production were studied. Plots were harvested in 1983 and 1984 for silage and seed. ...

  7. A new approach to study of seabird-fishery overlap: Connecting chick feeding with parental foraging and overlap with fishing vessels

    OpenAIRE

    Junichi Sugishita; Leigh G Torres; Philip J Seddon

    2015-01-01

    Incidental fisheries bycatch is recognised as a major threat to albatross populations worldwide. However, fishery discards and offal produced in large quantities might benefit some scavenging seabirds. Here, we demonstrate an integrated approach to better understand the ecological ramifications of fine-scale overlap between seabirds and fisheries. As a case study, we examined whether foraging in association with a fishing vessel is advantageous for chick provisioning in terms of quantity of f...

  8. Dworshak Dam Impact Assessment and Fishery Investigation and Trout, Bass and Forage Species: Combined Project Completion Report.

    Energy Technology Data Exchange (ETDEWEB)

    Maiolie, Melo; Statler, David P.; Elam, Steve

    1992-10-01

    The Nez Perce Tribe (NPT) and the Idaho Department of Fish and Game (IDFG) entered into separate intergovernmental agreements with the Bonneville Power Administration in a cooperative four-year effort to study impacts of Dworshak Dam operation on resident fisheries. The NPT Department of Fisheries Management focused on rainbow trout, smallmouth bass and forage fish. The IDFG's segment of the project was to document kokanee population dynamics, relate it to the changing nutrient status of the reservoir, evaluate kokanee losses through Dworshak Dam, and make kokanee management recommendations. This final report includes findings for 1990 and 1991 and relates these data to information previously presented in annual reports for 1987, 1988 and 1989.

  9. Dynamic habitat selection by two wading bird species with divergent foraging strategies in a seasonally fluctuating wetland

    Science.gov (United States)

    Beerens, J.M.; Gawlik, D.E.; Herring, G.; Cook, Mark I.

    2011-01-01

    Seasonal and annual variation in food availability during the breeding season plays an influential role in the population dynamics of many avian species. In highly dynamic ecosystems like wetlands, finding and exploiting food resources requires a flexible behavioral response that may produce different population trends that vary with a species' foraging strategy. We quantified dynamic foraging-habitat selection by breeding and radiotagged White Ibises (Eudocimus albus) and Great Egrets (Ardea alba) in the Florida Everglades, where fluctuation in food resources is pronounced because of seasonal drying and flooding. The White Ibis is a tactile "searcher" species in population decline that specializes on highly concentrated prey, whereas the Great Egret, in a growing population, is a visual "exploiter" species that requires lower prey concentrations. In a year with high food availability, resource-selection functions for both species included variables that changed over multiannual time scales and were associated with increased prey production. In a year with low food availability, resource-selection functions included short-term variables that concentrated prey (e.g., water recession rates and reversals in drying pattern), which suggests an adaptive response to poor foraging conditions. In both years, the White Ibis was more restricted in its use of habitats than the Great Egret. Real-time species-habitat suitability models were developed to monitor and assess the daily availability and quality of spatially explicit habitat resources for both species. The models, evaluated through hindcasting using independent observations, demonstrated that habitat use of the more specialized White Ibis was more accurately predicted than that of the more generalist Great Egret. ?? The American Ornithologists' Union, 2011.

  10. Production Performance of Root Systems of Four Forage Legume Species and Their Development Characteristics in Loess Plateau,China

    Institute of Scientific and Technical Information of China (English)

    Zhang; Jianquan; Zhang; Jiyu; Wang; Yanrong; Xie; Wengang; Li; Juncheng

    2014-01-01

    Production performance of four forage legumes species of Medicago sativa,Onobrychis viciifolia,Lotus corniculatus and Galega officinalis were determined,including plant height,above-ground biomass per unit area,tillers per unit area,fertile tillers per unit area,shoot /leaf ratio and fresh /dry matter weight ratio,and the distribution characteristics of their root systems in 0- 100 cm soil layers with 10 cm interval were studied. Results showed that the average aboveground fresh biomass(4 a and 5 a) of four forage legumes species successively were L. corniculatus > M. sativa > O. viciifolia > G. officinalis. The average plant heights in two years successively were O. viciifolia > M. sativa > G. officinalis > L. corniculatus. Tillers per unit area of four forage legume species in two years successively were M. sativa > L. corniculatus > O. viciifolia > G. officinalis. Fertile tillers per unit area in two years were O. viciifolia > M. sativa > L. corniculatus > G. officinalis. Average shoot /leaf ratio in two years were G. officinalis > M. sativa > O. viciifolia > L. corniculatus. Average moisture contents of four forage legume species in two years successively were G. officinalis > L. corniculatus > M. sativa = O. viciifolia. The distribution characteristics of root systems of four forage legumes species in 0- 100 cm soil layers were as follows: the root weights of M. sativa in 0- 40 cm soil layers accounted for about 98. 3% of total root weight,that of O. viciifolia in 0- 30 cm soil layers was 85. 8%,that of L. corniculatus in 0- 10 cm soil layers was 80%,and that of G. officinalis in 0- 40 cm soil layers was 81. 4%. The results suggested that L. corniculatus was suited to plant in slighter degraded pasture to control water and soil erosion in early stage,G. officinalis with strong lateral roots was adapted to degraded grassland in the Loess Plateau where soil nutrient was poor,while O. viciifolia and M. sativa with potentially strong main root were fit for water

  11. Detection of Vibrio Species Isolated from Ornamental Guppy Fish in Kashan, Isfahan, Iran Fish culturing Pounds

    Directory of Open Access Journals (Sweden)

    Samira Kiani

    2016-03-01

    Full Text Available Introduction: Gram-negative bacteria are the most pathogenic bacteria for marine organisms including ornamental fish. Materials and methods: In the present study Vibrio species isolated from ornamental guppy fish in Kashan, Isfahan, Iran fish ponds and were detected according to molecular detection and genetic alignment. Liver, kidney, skin, brain and gill samples were taken from ornamental guppy fish in Kashan, Isfahan, Iran. Samples were cultured on enriched culture media and purification steps were performed based on microbiological methods. Primary identification was done using biochemical characterization of the isolated bacteria. Molecular detection was done based on amplification of 16SrDNA sequence of Vibrio cholera genome containing ITS (internal transcribed spacer; and sequence alignment of the amplified nucleotides. Results: The isolated bacteria detected as Vibrio spp., including Vibrio cholera (99% sequence similarity, Vibrio alginolyticus, Vibrio mimicus and Vibrio parahaemolyticus (up to 90% similarity in the genome sequence. The aquaculture ponds had alkaline water and the amount of five-day BOD was not in a safe range, which are favorable conditions for Vibrio species. Discussion and conclusion: Aquatic organisms in Iran can be carriers of human pathogens such as Vibrio species. The results obtained in the present study and similar investigations should be mentioned in aquaculture healthcare systems.

  12. A highly permeable species boundary between two anadromous fishes.

    Science.gov (United States)

    Coscia, I; Rountree, V; King, J J; Roche, W K; Mariani, S

    2010-10-01

    Meristic identification, mitochondrial DNA and a suite of microsatellite markers were employed to estimate the incidence of hybridization in wild populations of anadromous Allis shad Alosa alosa and twaite shad Alosa fallax in southern Irish riverine and estuarine waters. It was shown that 16% of the fishes examined were misclassified using meristic count of gill rakers. Next, a significant proportion of fishes that were robustly assigned to a species using nuclear markers were shown to possess the mtDNA of the other. The genomes of A. alosa and A. fallax in Ireland are extensively introgressed, which suggests a complex history of hybridization between these species, which can only partially be explained by recent man-made habitat changes.

  13. Yield and Quality of Forage Sorghum and Different Amaranth Species (Amaranthus spp. Biomass

    Directory of Open Access Journals (Sweden)

    Ana Pospišil

    2009-06-01

    Full Text Available The objective of investigations carried out on the experimental field of the Faculty of Agriculture, Zagreb, in 2002, 2003 and 2004 was to compare green mass and dry matter yields of forage sorghum and amaranth, and the nutritional value of these two crops at several development stages. Investigations included two amaranth cultivars: ‘1008’ (Amaranthus hypochondriacus L. and ‘Koniz’ (Amaranthus hypochondriacus L. x Amaranthus hybridus L., and forage sorghum, hybrid Grazer N (Sorghum bicolor x S. sudanense. In all three trial years, forage sorghum gave the highest green mass and dry matter yield at the tasselling stage. In 2003, also amaranth, cultivar 1008, gave a high green mass yield at the flowering, which was in the same rank as forage sorghum. Decline of biomass quality was observed at later development stages due to a decrease in the concentration of crude and digestible proteins and an increase in NDF (neutral detergent fibre and ADF (acid detergent fibre concentrations. High quality of amaranth biomass was determined. Higher concentrations of crude and digestible proteins were found in amaranth aboveground biomass compared to forage sorghum while sorghum had a higher NDF concentration.

  14. Phototaxic foraging of the archaepaddler, a hypothetical deep-sea species.

    Science.gov (United States)

    Bertin, R J; van de Grind, W A

    1998-01-01

    An autonomous agent (animat, hypothetical animal), called the (archae) paddler, is simulated in sufficient detail to regard its simulated aquatic locomotion (paddling) as physically possible. The paddler is supposed to be a model of an animal that might exist, although it is perfectly possible to view it as a model of a robot that might be built. The agent is assumed to navigate in a simulated deep-sea environment, where it forages for autoluminescent prey. It uses a biologically inspired phototaxic foraging strategy, while paddling in a layer just above the bottom. The advantage of this living space is that the navigation problem--and hence our model--is essentially two-dimensional. Moreover, the deep-sea environment is physically simple (and hence easy to simulate): no significant currents, constant temperature, completely dark. A foraging performance metric is developed that circumvents the necessity to solve the traveling salesman problem. A parametric simulation study then quantifies the influence of habitat factors, such as the density of prey, and body geometry (e.g., placement, direction and directional selectivity of the eyes) on foraging success. Adequate performance proves to require a specific body geometry adapted to the habitat characteristics. In general, performance degrades gracefully for modest changes of the geometric and habitat parameters, indicating that we work in a stable region of "design space." The parameters have to strike a compromise between, on the one hand, to "see" as many targets at the same time as possible. One important conclusion is that simple reflex-based navigation can be surprisingly efficient. Additionally, performance in a global task (foraging) depends strongly on local parameters such as visual direction tuning, position of the eyes and paddles, and so forth. Behavior and habitat "mold" the body, and the body geometry strongly influences performance. The resulting platform enables further testing of foraging strategies

  15. Variation in fatty acid composition among nine forage species from a southeastern US estuarine and nearshore coastal ecosystem.

    Science.gov (United States)

    Recks, Melissa A; Seaborn, Gloria T

    2008-09-01

    The fatty acid (FA) composition of nine potentially important forage species was determined (n = 330): red drum (Sciaenops ocellatus), spot (Leiostomus xanthurus), spotted seatrout (Cynoscion nebulosus), striped mullet (Mugil cephalus), pinfish (Lagodon rhomboides), Atlantic croaker (Micropogonias undulatus), star drum (Stellifer lanceolatus), striped anchovy (Anchoa hepsetus), and brief squid (Lolliguncula brevis). Samples were collected from estuarine and nearshore coastal waters around Charleston, South Carolina, USA, from March 2002-February 2003. Twenty-nine of 125 identified FAs were included in multivariate analyses of FA profiles. Despite existing intraspecific variation, the PRIMER routine analysis of similarity (ANOSIM) indicated each species was distinct, and discriminant function analysis correctly classified 99.5% of the training data set samples (n = 221) and 98.2% of the validation samples (n = 109). Most species could be characterized by distinctive levels of a suite of FAs. Our results indicated FA profiles can be used to reliably distinguish even closely related forage species in this southeastern US estuarine ecosystem. The information gained from this study not only provides insight into the biochemical composition of these important species but also provides fundamental information to support studies on the feeding ecology of local higher-level predators.

  16. Tree species preferences of foraging songbirds during spring migration in floodplain forests of the Upper Mississippi River

    Science.gov (United States)

    Kirsch, Eileen M.; Wellik, Mike J.

    2017-01-01

    Floodplain forest of the Upper Mississippi River is important for songbirds during spring migration. However, the altered hydrology of this system and spread of reed canary grass (Phalaris arundinacea) and emerald ash borer (Agrilus planipennis) threaten tree diversity and long-term sustainability of this forest. We estimated tree preferences of songbirds during spring migration 2010–2013 to help guide management decisions that promote tree diversity and forest sustainability and to evaluate yearly variation in tree selection. We used the point center-quarter method to assess relative availability of tree species and tallied bird foraging observations on tree species as well as recording the phenophase of used trees on five 40 ha plots of contiguous floodplain forest between La Crosse, Wisconsin and New Albin, Iowa, from 15 April through 1 June. We quantified bird preferences by comparing proportional use of tree species by each bird species to estimates of tree species availability for all 4 y and for each year separately. Species that breed locally preferred silver maple (Acer saccharinum), which is dominant in this forest. The common transient migrant species and the suite of 17 transient wood warbler species preferred hackberry (Celtis occidentalis) and oaks (Quercus spp.), which are limited to higher elevations on the floodplain. We observed earlier leaf development the warm springs of 2010 and 2012 and later leaf development the cold springs of 2011 and 2013. Yellow-rumped Warbler (Setophaga coronata), American Redstart (S. ruticilla), Warbling Vireo (Vireo gilvus) and Baltimore Oriole (Icterus galbula), and the suite of transient migrant wood warblers spread their foraging efforts among tree species in colder springs and were more selective in warmer springs. All three of the important tree species are not regenerating well on the UMR and widespread die-off of silver maple is possible in 50 y without large scale management.

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

    Science.gov (United States)

    França, Susana; Cabral, Henrique N.

    2016-10-01

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

  18. The Colletotrichum destructivum species complex - hemibiotrophic pathogens of forage and field crops

    NARCIS (Netherlands)

    Damm, U.; O'Connell, R.J.; Groenewald, J.Z.; Crous, P.W.

    2014-01-01

    Colletotrichum destructivum is an important plant pathogen, mainly of forage and grain legumes including clover, alfalfa, cowpea and lentil, but has also been reported as an anthracnose pathogen of many other plants worldwide. Several Colletotrichum isolates, previously reported as closely related t

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

    Science.gov (United States)

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

    2015-10-01

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

  20. Foraging behavior and success of a mesopelagic predator in the northeast Pacific Ocean: insights from a data-rich species, the northern elephant seal.

    Directory of Open Access Journals (Sweden)

    Patrick W Robinson

    Full Text Available The mesopelagic zone of the northeast Pacific Ocean is an important foraging habitat for many predators, yet few studies have addressed the factors driving basin-scale predator distributions or inter-annual variability in foraging and breeding success. Understanding these processes is critical to reveal how conditions at sea cascade to population-level effects. To begin addressing these challenging questions, we collected diving, tracking, foraging success, and natality data for 297 adult female northern elephant seal migrations from 2004 to 2010. During the longer post-molting migration, individual energy gain rates were significant predictors of pregnancy. At sea, seals focused their foraging effort along a narrow band corresponding to the boundary between the sub-arctic and sub-tropical gyres. In contrast to shallow-diving predators, elephant seals target the gyre-gyre boundary throughout the year rather than follow the southward winter migration of surface features, such as the Transition Zone Chlorophyll Front. We also assessed the impact of added transit costs by studying seals at a colony near the southern extent of the species' range, 1,150 km to the south. A much larger proportion of seals foraged locally, implying plasticity in foraging strategies and possibly prey type. While these findings are derived from a single species, the results may provide insight to the foraging patterns of many other meso-pelagic predators in the northeast Pacific Ocean.

  1. Habitat-specific foraging strategies in Australasian gannets

    Directory of Open Access Journals (Sweden)

    Melanie R. Wells

    2016-07-01

    Full Text Available Knowledge of top predator foraging adaptability is imperative for predicting their biological response to environmental variability. While seabirds have developed highly specialised techniques to locate prey, little is known about intraspecific variation in foraging strategies with many studies deriving information from uniform oceanic environments. Australasian gannets (Morus serrator typically forage in continental shelf regions on small schooling prey. The present study used GPS and video data loggers to compare habitat-specific foraging strategies at two sites of contrasting oceanographic regimes (deep water near the continental shelf edge, n=23; shallow inshore embayment, n=26, in south-eastern Australia. Individuals from the continental shelf site exhibited pelagic foraging behaviours typical of gannet species, using local enhancement to locate and feed on small schooling fish; in contrast only 50% of the individuals from the inshore site foraged offshore, displaying the typical pelagic foraging strategy. The remainder adopted a strategy of searching sand banks in shallow inshore waters in the absence of conspecifics and other predators for large, single prey items. Furthermore, of the individuals foraging inshore, 93% were male, indicating that the inshore strategy may be sex-specific. Large inter-colony differences in Australasian gannets suggest strong plasticity in foraging behaviours, essential for adapting to environmental change.

  2. Habitat-specific foraging strategies in Australasian gannets.

    Science.gov (United States)

    Wells, Melanie R; Angel, Lauren P; Arnould, John P Y

    2016-07-15

    Knowledge of top predator foraging adaptability is imperative for predicting their biological response to environmental variability. While seabirds have developed highly specialised techniques to locate prey, little is known about intraspecific variation in foraging strategies with many studies deriving information from uniform oceanic environments. Australasian gannets (Morus serrator) typically forage in continental shelf regions on small schooling prey. The present study used GPS and video data loggers to compare habitat-specific foraging strategies at two sites of contrasting oceanographic regimes (deep water near the continental shelf edge, n=23; shallow inshore embayment, n=26), in south-eastern Australia. Individuals from the continental shelf site exhibited pelagic foraging behaviours typical of gannet species, using local enhancement to locate and feed on small schooling fish; in contrast only 50% of the individuals from the inshore site foraged offshore, displaying the typical pelagic foraging strategy. The remainder adopted a strategy of searching sand banks in shallow inshore waters in the absence of conspecifics and other predators for large, single prey items. Furthermore, of the individuals foraging inshore, 93% were male, indicating that the inshore strategy may be sex-specific. Large inter-colony differences in Australasian gannets suggest strong plasticity in foraging behaviours, essential for adapting to environmental change.

  3. Seasonal Changes in Leaf Tissue Rehydration of One Annual and Two Perennial Grass Forage Species Induced by Bioclimate

    Directory of Open Access Journals (Sweden)

    Eirini - Ia KAPSALI

    2015-12-01

    Full Text Available Bioclimate signifies the continuous interplay between plants and climate factors (primarily drought and has a direct impact on the water relations and the duration of the rehydration process in water stressed plants. To explore the association between bioclimate and water physiology of forage species in semi-arid Mediterranean grasslands, we determined the seasonal variation in leaf water potential, turgid weight and relative water content in wild growing Dactylis glomerata L., Bromus inermis Leyss (perennial and Bromus sterilis L. (annual during the growing season. The study was conducted at the farm of the Aristotle University of Thessaloniki. The results of the current study reveal that B. sterilis maintained high levels of water potential most probably by accelerating its biological cycle and decreasing water content because it fails to sustain turgidity. Dactylis glomerata and B. inermis presented even higher water contents than B. sterilis for the same water potential. Dactylis glomerata exhibited substantially higher water potential and content than B. inermis by keeping the rehydration duration stable. The extensive creeping rhizome seems to allow B. inermis to sustain high values of water potential and content possibly ensuring turgidity. Regardless of the grass species the duration of rehydration ranged from 2.5 to 3.5 hours throughout the growing season. Our findings demonstrate that (a D. glomerata and B. inermis are better adapted to Mediterranean semiarid conditions than B. sterilis and (b turgid weight in Mediterranean forage species can safely be determined after a rehydration period of 3.5 hours.

  4. 78 FR 18273 - Draft Guidance for Industry on Purchasing Reef Fish Species Associated With the Hazard of...

    Science.gov (United States)

    2013-03-26

    ... Reef Fish Species Associated With the Hazard of Ciguatera Fish Poisoning; Availability AGENCY: Food and...: Purchasing Reef Fish Species Associated With the Hazard of Ciguatera Fish Poisoning.'' The draft guidance... of ciguatera fish poisoning (CFP) from fish that they distribute. The draft guidance is intended...

  5. Logging impacts on avian species richness and composition differ across latitudes and foraging and breeding habitat preferences.

    Science.gov (United States)

    LaManna, Joseph A; Martin, Thomas E

    2016-10-10

    Understanding the causes underlying changes in species diversity is a fundamental pursuit of ecology. Animal species richness and composition often change with decreased forest structural complexity associated with logging. Yet differences in latitude and forest type may strongly influence how species diversity responds to logging. We performed a meta-analysis of logging effects on local species richness and composition of birds across the world and assessed responses by different guilds (nesting strata, foraging strata, diet, and body size). This approach allowed identification of species attributes that might underlie responses to this anthropogenic disturbance. We only examined studies that allowed forests to regrow naturally following logging, and accounted for logging intensity, spatial extent, successional regrowth after logging, and the change in species composition expected due to random assembly from regional species pools. Selective logging in the tropics and clearcut logging in temperate latitudes caused loss of species from nearly all forest strata (ground to canopy), leading to substantial declines in species richness (up to 27% of species). Few species were lost or gained following any intensity of logging in lower-latitude temperate forests, but the relative abundances of these species changed substantially. Selective logging at higher-temperate latitudes generally replaced late-successional specialists with early-successional specialists, leading to no net changes in species richness but large changes in species composition. Removing less basal area during logging mitigated the loss of avian species from all forests and, in some cases, increased diversity in temperate forests. This meta-analysis provides insights into the important role of habitat specialization in determining differential responses of animal communities to logging across tropical and temperate latitudes.

  6. Logging impacts on avian species richness and composition differ across latitudes relative to foraging and breeding habitat preferences

    Science.gov (United States)

    LaManna, Joseph A.; Martin, Thomas E.

    2017-01-01

    Understanding the causes underlying changes in species diversity is a fundamental pursuit of ecology. Animal species richness and composition often change with decreased forest structural complexity associated with logging. Yet differences in latitude and forest type may strongly influence how species diversity responds to logging. We performed a meta-analysis of logging effects on local species richness and composition of birds across the world and assessed responses by different guilds (nesting strata, foraging strata, diet, and body size). This approach allowed identification of species attributes that might underlie responses to this anthropogenic disturbance. We only examined studies that allowed forests to regrow naturally following logging, and accounted for logging intensity, spatial extent, successional regrowth after logging, and the change in species composition expected due to random assembly from regional species pools. Selective logging in the tropics and clearcut logging in temperate latitudes caused loss of species from nearly all forest strata (ground to canopy), leading to substantial declines in species richness (up to 27% of species). Few species were lost or gained following any intensity of logging in lower-latitude temperate forests, but the relative abundances of these species changed substantially. Selective logging at higher-temperate latitudes generally replaced late-successional specialists with early-successional specialists, leading to no net changes in species richness but large changes in species composition. Removing less basal area during logging mitigated the loss of avian species from all forests and, in some cases, increased diversity in temperate forests. This meta-analysis provides insights into the important role of habitat specialization in determining differential responses of animal communities to logging across tropical and temperate latitudes.

  7. Interactions between shoal size and conformity in guppy social foraging

    NARCIS (Netherlands)

    Day, R.L.; Macdonald, T.; Brown, C.; Laland, K.N.; Reader, S.M.

    2001-01-01

    Previous experimental studies have established that shoaling fish forage more effectively in large than small groups. We investigated how shoal size affects the foraging efficiency of laboratory populations of the guppy, Poecilia reticulata, exposed to different foraging tasks. Experiment 1

  8. Diversity of the skin microbiota of fishes: evidence for host species specificity.

    Science.gov (United States)

    Larsen, Andrea; Tao, Zhen; Bullard, Stephen A; Arias, Covadonga R

    2013-09-01

    Skin microbiota of Gulf of Mexico fishes were investigated by ribosomal internal spacer analysis (RISA) and 16S rRNA gene sequencing. A total of 102 fish specimens representing six species (Mugil cephalus, Lutjanus campechanus, Cynoscion nebulosus, Cynoscion arenarius, Micropogonias undulatus, and Lagodon rhomboides) were sampled at regular intervals throughout a year. The skin microbiota from each individual fish was analyzed by RISA and produced complex profiles with 23 bands on average. Similarities between RISA profiles ranged from 97.5% to 4.0%. At 70% similarity, 11 clusters were defined, each grouping individuals from the same fish species. Multidimensional scaling and analysis of similarity correlated the RISA-defined clusters with geographic locality, date, and fish species. Global R values indicated that fish species was the most indicative variable for group separation. Analysis of 16S rRNA gene sequences (from pooled samples of 10 individual fish for each fish species) showed that the Proteobacteria was the predominant phylum in skin microbiota, followed by the Firmicutes and the Actinobacteria. The distribution and abundance of bacterial sequences were different among all species analyzed. Aeribacillus was found in all fish species representing 19% of all clones sequenced, while some genera were fish species-specific (Neorickettsia in M. cephalus and Microbacterium in L. campechanus). Our data provide evidence for the existence of specific skin microbiota associated with particular fish species. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  9. Metazoan parasite species richness in Neotropical fishes: hotspots and the geography of biodiversity.

    Science.gov (United States)

    Luque, J L; Poulin, R

    2007-06-01

    Although research on parasite biodiversity has intensified recently, there are signs that parasites remain an underestimated component of total biodiversity in many regions of the planet. To identify geographical hotspots of parasite diversity, we performed qualitative and quantitative analyses of the parasite-host associations in fishes from Latin America and the Caribbean, a region that includes known hotspots of plant and animal biodiversity. The database included 10,904 metazoan parasite-host associations involving 1660 fish species. The number of host species with at least 1 parasite record was less than 10% of the total known fish species in the majority of countries. Associations involving adult endoparasites in actinopterygian fish hosts dominated the database. Across the whole region, no significant difference in parasite species richness was detected between marine and freshwater fishes. As a rule, host body size and study effort (number of studies per fish species) were good predictors of parasite species richness. Some interesting patterns emerged when we included only the regions with highest fish species biodiversity and study effort (Brazil, Mexico and the Caribbean Islands). Independently of differences in study effort or host body sizes, Mexico stands out as a hotspot of parasite diversity for freshwater fishes, as does Brasil for marine fishes. However, among 57 marine fish species common to all 3 regions, populations from the Caribbean consistently harboured more parasite species. These differences may reflect true biological patterns, or regional discrepancies in study effort and local priorities for fish parasitology research.

  10. Diversity of Fusarium species isolated from UK forage maize and the population structure of F. graminearum from maize and wheat.

    Science.gov (United States)

    Basler, Ryan

    2016-01-01

    Pre-harvest contamination of forage maize by mycotoxin producing Fusarium species was investigated in the UK in 2011 and 2012. A total of 15 Fusarium species were identified from a collection of 1,761 Fusarium isolates recovered from maize stalks and kernels. This study characterized the diversity of Fusarium species present in forage maize in the UK. The predominant species detected were F. graminearum (32.9%) and F. culmorum (34.1%). Along with those species; F. avenacem, F. cerealis, F. equiseti, F. langsethiae, F. napiforme, F. oxysporum, F. poae, F. proliferatum, F. scripi, F. solani, F. subglutinans, F. tricinctum and, F. verticillioides were occasionally isolated. The trichothecene genotypes for F. graminearum were determined to be 84.9% deoxynivalenol (DON) and 15.0% nivalenol (NIV) while F. culmorum isolates were determined to have 24.9% DON and 75.1% NIV genotypes. A Bayesian model-based clustering method with nine variable number of tandem repeat markers was used to evaluate the population genetic structure of 277 F. graminearum isolates from the maize and wheat in the UK. There were three genetic clusters detected which were DON in maize, NIV in maize and DON in wheat. There were high admixture probabilities for 14.1% of the isolates in the populations. In conclusion, increased maize production in the UK and the high admixture rates in a significant portion of F. graminearum populations in maize and wheat will contribute to a new pathogen population which will further complicate breeding strategies for tolerance or resistance to this pathogen in both crops.

  11. Distribution of the three major species of fish in the Hartbeespoort ...

    African Journals Online (AJOL)

    1985-08-05

    Aug 5, 1985 ... ... of fish in the. Hartbeespoort Dam in relation to some environmental .... The factors considered most likely to influence fish distribution were ..... and species diversity of benthic invertebrates decreases with increasing depth ...

  12. Fish species list for Carolina Sandhills National Wildlife Refuge, Chesterfield County, South Carolina

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Document includes the following information about the fish species found on the refuge: commonname (scientific name), field number(s), date(s) and stream name(s)....

  13. Foraging segregation of two congeneric diving seabird species (common and thick-billed murres breeding on St. George Island, Bering Sea

    Directory of Open Access Journals (Sweden)

    N. Kokubun

    2015-11-01

    Full Text Available Sub-arctic environmental changes are expected to affect the ecology of marine top predators. We examined the characteristics of foraging behavior of two sympatric congeneric diving seabirds, common (Uria aalge: hereafter COMU and thick-billed (U. lomvia: hereafter TBMU murres breeding on St. George Island located in the seasonal sea-ice region of the Bering Sea. We investigated their flight duration, diel patterns of dive depth, and underwater wing strokes, along with morphology and blood stable isotopes. Acceleration-temperature-depth data loggers were attached to chick-guarding birds, and behavioral data were obtained from 7 COMU and 12 TBMU. Both species showed similar trip duration (13.21 ± 4.79 h for COMU and 10.45 ± 7.09 h for TBMU and similar diurnal patterns of diving (frequent dives to various depths in the daytime and less frequent dives to shallow depths in the nighttime. During the daytime, dive depths of COMU had two peaks in shallow (18.1 ± 6.0 m and deep (74.2 ± 8.7 m depths, while those of TBMU were 20.2 ± 7.4 m and 59.7 ± 7.9 m. COMU showed more frequent wing strokes during the bottom phase of dives (1.90 ± 0.11 s−1 than TBMU (1.66 ± 0.15 s−1. Fishes occurred with higher proportion in the bill-loads brought back to chicks in COMU (85 % than in TBMU (56 %. δ15N value of blood was significantly higher in COMU (14.47 ± 0.27 ‰ than in TBMU (13.14 ± 0.36 ‰. Relatively small wing area (0.053 ± 0.007 m2 of COMU compared to TBMU (0.067 ± 0.007 m2 may make them more agile underwater and thus enable them to target more mobile prey including larger fishes that inhabit deeper depths. These differences in foraging behavior between COMU and TBMU might explain the differences in their responses to long-term marine environmental changes.

  14. Foraging Activity of Four Bee Species on Sesame Flowers During Two Successive Seasons in Ismailia Governorate, Egypt

    Directory of Open Access Journals (Sweden)

    Soliman M. Kamel

    2013-01-01

    Full Text Available Foraging activity of four bee species, Apis mellifera L., Osmia spp., Ceratina tarsataMorawitz and Xylocopa pubescens Spinola on sesame flowers was studied during two successiveseasons of 2011 and 2012. Experimental observations were made during four periodsof the day: 9:00-11:00 am, 11:00 am-1:00 pm, 1:00-3:00 pm and 3:00-5:00 pm, startingfrom initial flowering until the final session. Observation time was five minutes during eachperiod and four bee species were observed visiting each square meter area. Five spots of 1m2 area were selected randomly, and the number of different species of bees visiting wascounted for five minutes by using electronic stopwatch, voice recorder and digital videocamera. The results of the study indicated that the four bee species were most abundanton sesame flowers between 11:00 am and 1:00 pm, and between 1:00 and 3:00 pm. Amongthe bees, Apis mellifera was the predominant species, followed by Ceratina tarsata, in theseason of 2011, while a reverse order of the two was recorded in 2012. The average timespent per flower was highly significantly different among these four species.

  15. The Foraging Ecology of the Endangered Cape Verde Shearwater, a Sentinel Species for Marine Conservation off West Africa.

    Science.gov (United States)

    Paiva, Vitor H; Geraldes, Pedro; Rodrigues, Isabel; Melo, Tommy; Melo, José; Ramos, Jaime A

    2015-01-01

    Large Marine Ecosystems such as the Canary Current system off West Africa sustains high abundance of small pelagic prey, which attracts marine predators. Seabirds are top predators often used as biodiversity surrogates and sentinel species of the marine ecosystem health, thus frequently informing marine conservation planning. This study presents the first data on the spatial (GPS-loggers) and trophic (stable isotope analysis) ecology of a tropical seabird-the endangered Cape Verde shearwater Calonectris edwardsii-during both the incubation and the chick-rearing periods of two consecutive years. This information was related with marine environmental predictors (species distribution models), existent areas of conservation concern for seabirds (i.e. marine Important Bird Areas; marine IBAs) and threats to the marine environment in the West African areas heavily used by the shearwaters. There was an apparent inter-annual consistency on the spatial, foraging and trophic ecology of Cape Verde shearwater, but a strong alteration on the foraging strategies of adult breeders among breeding phases (i.e. from incubation to chick-rearing). During incubation, birds mostly targeted a discrete region off West Africa, known by its enhanced productivity profile and thus also highly exploited by international industrial fishery fleets. When chick-rearing, adults exploited the comparatively less productive tropical environment within the islands of Cape Verde, at relatively close distance from their breeding colony. The species enlarged its trophic niche and increased the trophic level of their prey from incubation to chick-rearing, likely to provision their chicks with a more diversified and better quality diet. There was a high overlap between the Cape Verde shearwaters foraging areas with those of European shearwater species that overwinter in this area and known areas of megafauna bycatch off West Africa, but very little overlap with existing Marine Important Bird Areas. Further

  16. The Foraging Ecology of the Endangered Cape Verde Shearwater, a Sentinel Species for Marine Conservation off West Africa.

    Directory of Open Access Journals (Sweden)

    Vitor H Paiva

    Full Text Available Large Marine Ecosystems such as the Canary Current system off West Africa sustains high abundance of small pelagic prey, which attracts marine predators. Seabirds are top predators often used as biodiversity surrogates and sentinel species of the marine ecosystem health, thus frequently informing marine conservation planning. This study presents the first data on the spatial (GPS-loggers and trophic (stable isotope analysis ecology of a tropical seabird-the endangered Cape Verde shearwater Calonectris edwardsii-during both the incubation and the chick-rearing periods of two consecutive years. This information was related with marine environmental predictors (species distribution models, existent areas of conservation concern for seabirds (i.e. marine Important Bird Areas; marine IBAs and threats to the marine environment in the West African areas heavily used by the shearwaters. There was an apparent inter-annual consistency on the spatial, foraging and trophic ecology of Cape Verde shearwater, but a strong alteration on the foraging strategies of adult breeders among breeding phases (i.e. from incubation to chick-rearing. During incubation, birds mostly targeted a discrete region off West Africa, known by its enhanced productivity profile and thus also highly exploited by international industrial fishery fleets. When chick-rearing, adults exploited the comparatively less productive tropical environment within the islands of Cape Verde, at relatively close distance from their breeding colony. The species enlarged its trophic niche and increased the trophic level of their prey from incubation to chick-rearing, likely to provision their chicks with a more diversified and better quality diet. There was a high overlap between the Cape Verde shearwaters foraging areas with those of European shearwater species that overwinter in this area and known areas of megafauna bycatch off West Africa, but very little overlap with existing Marine Important Bird

  17. Determining spatio-temporal distribution of bee forage species of Al-Baha region based on ground inventorying supported with GIS applications and Remote Sensed Satellite Image analysis.

    Science.gov (United States)

    Adgaba, Nuru; Alghamdi, Ahmed; Sammoud, Rachid; Shenkute, Awraris; Tadesse, Yilma; Ansari, Mahammad J; Sharma, Deepak; Hepburn, Colleen

    2017-07-01

    In arid zones, the shortage of bee forage is critical and usually compels beekeepers to move their colonies in search of better forages. Identifying and mapping the spatiotemporal distribution of the bee forages over given area is important for better management of bee colonies. In this study honey bee plants in the target areas were inventoried following, ground inventory work supported with GIS applications. The study was conducted on 85 large plots of 50 × 50 m each. At each plot, data on species name, height, base diameter, crown height, crown diameter has been taken for each plant with their respective geographical positions. The data were stored, and processed using Trimble GPS supported with ArcGIS10 software program. The data were used to estimate the relative frequency, density, abundance and species diversity, species important value index and apicultural value of the species. In addition, Remotely Sensed Satellite Image of the area was obtained and processed using Hopfield Artificial Neural Network techniques. During the study, 182 species from 49 plant families were identified as bee forages of the target area. From the total number of species; shrubs, herbs and trees were accounting for 61%, 27.67%, and 11.53% respectively. Of which Ziziphus spina-christi, Acacia tortilis, Acacia origina, Acacia asak, Lavandula dentata, and Hypoestes forskaolii were the major nectar source plants of the area in their degree of importance. The average vegetation cover values of the study areas were low (place. The Remote Sensed Satellite Image analysis confirmed the spatial distribution of the bee forage resources as determined by the ground inventory work. An integrated approach, combining the ground inventory work with GIS and satellite image processing techniques could be an important tool for characterizing and mapping the available bee forage resources leading to their efficient and sustainable utilization.

  18. Mercury pollution in fish from South China Sea: levels, species-specific accumulation, and possible sources.

    Science.gov (United States)

    Liu, Jinling; Xu, Xiangrong; Yu, Shen; Cheng, Hefa; Hong, Yiguo; Feng, Xinbin

    2014-05-01

    Both total mercury (THg) and methylmercury (MeHg) levels in fish collected from South China Sea (SCS) were studied to understand Hg pollution in Chinese tropical marine ecosystems. The average THg concentrations in fish species ranged from 39.6 μg/kg for rabbitfish (Siganus fuscessens) to 417 μg/kg for thornfish (Terapon jarbua), while those of MeHg varied from 13 μg/kg (rabbitfish) to 176 μg/kg (thornfish). The median values of MeHg/THg ratios in different fish species ranged from 36 to 85%. Significant inter-species differences of THg and MeHg in fish were observed due to feeding habits and fish sizes. Overall, carnivorous fish had higher levels of THg, MeHg and MeHg/THg ratios than omnivorous and herbivorous fish. High Hg levels in fish of the SCS were probably related to Hg input from atmospheric deposition and anthropogenic activities.

  19. Influence of honey bee, Apis mellifera, hives and field size on foraging activity of native bee species in pumpkin fields.

    Science.gov (United States)

    Artz, Derek R; Hsu, Cynthia L; Nault, Brian A

    2011-10-01

    The purpose of this study was to identify bee species active in pumpkin fields in New York and to estimate their potential as pollinators by examining their foraging activity. In addition, we examined whether foraging activity was affected by either the addition of hives of the honey bee, Apis mellifera L., or by field size. Thirty-five pumpkin (Cucurbita spp.) fields ranging from 0.6 to 26.3 ha, 12 supplemented with A. mellifera hives and 23 not supplemented, were sampled during peak flowering over three successive weeks in 2008 and 2009. Flowers from 300 plants per field were visually sampled for bees on each sampling date. A. mellifera, Bombus impatiens Cresson, and Peponapis pruinosa (Say) accounted for 99% of all bee visits to flowers. A. mellifera and B. impatiens visited significantly more pistillate flowers than would be expected by chance, whereas P. pruinosa showed no preference for visiting pistillate flowers. There were significantly more A. mellifera visits per flower in fields supplemented with A. mellifera hives than in fields not supplemented, but there were significantly fewer P. pruinosa visits in supplemented fields. The number of B. impatiens visits was not affected by supplementation, but was affected by number of flowers per field. A. mellifera and P. pruinosa visits were not affected by field size, but B. impatiens visited fewer flowers as field size increased in fields that were not supplemented with A. mellifera hives. Declining A. mellifera populations may increase the relative importance of B. impatiens in pollinating pumpkins in New York.

  20. Study of parasites native and introduced species of fish in Caspian Sea

    OpenAIRE

    Bozorgnia, Abbas

    2007-01-01

    Seven native and introduced species of fish in south east Caspian Sea coast examined for parasite infestation during 2004-2006. Native fishes include Barbus capito, Carassius auratus, Cyprinus carpio, Rutilus frisii kutum, Rutilus rutilus, Stizostidion lucioperca, Alosa caspia persica, 24 ecto and endo parasites were found in different organs of 7 species of fishes of them 2 of the metazoan 12 species of crustacean Lernaea cyprinacea , Lamproglena pukhella nematodea and cestodea parasite were...

  1. California Least Tern Foraging Ecology in Southern California: A Review of Foraging Behavior Relative to Proposed Dredging Locations

    Science.gov (United States)

    2016-05-01

    freshwater species, including killifish (Fundulus parvipinnis) and mosquito fish (Gambusia affinis) (Atwood and ERDC/EL CR-16-3 2 Kelly 1984...event of oil spill. Three portable pools with mosquito fish provided near Pier 400 nesting site. Included surveys at 3 preferred foraging areas...review summarized available information on CLT biology , ecology, and predators in the first four sections; Section 5 is entitled “Known Effects of

  2. 78 FR 69992 - Guidance for Industry on Purchasing Reef Fish Species Associated With the Hazard of Ciguatera...

    Science.gov (United States)

    2013-11-22

    ... Fish Species Associated With the Hazard of Ciguatera Fish Poisoning; Availability AGENCY: Food and Drug... Species Associated with the Hazard of Ciguatera Fish Poisoning.'' The document provides guidance to primary seafood processors who purchase reef fish on how to minimize the risk of ciguatera fish...

  3. Fish passage in plains and prairie waterways and predicting fish response to climate change: Fine scale fish passage and physiological response data needed to restore and conserve plains and prairie pothole fish species

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The research aims to build on two existing projects underway: (1) to improve fish passage and landscape connectivity for native species; and (2) determine thermal...

  4. Differences in sensitivity of native and exotic fish species to changes in river temperature

    Institute of Scientific and Technical Information of China (English)

    R.S.E.W. LEUVEN; A.J. HENDRIKS; M.A.J. HULJBREGTS; H.J.R. LENDERS; J. MATTHEWS; G. VAN DER VELDE

    2011-01-01

    This paper describes the effects that temperature changes in the Rhine river distributaries have on native and exotic fish diversity.Site-specific potentially affected fractions (PAFs) of the regional fish species pool were derived using species sensitivity distributions (SSDs) for water temperature.The number of fish species in the river distributaries has changed remarkably over the last century.The number of native rheophilous species declined up until 1980 due to anthropogenic disturbances such as commercial fishing,river regulation,migration barriers,habitat deterioration and water pollution.In spite of progress in river rehabilitation,the native rheophilous fish fauna has only partially recovered thus far.The total number of species has strongly increased due to the appearance of more exotic species.After the opening of the Rhine-Main-Danube waterway in 1992,many fish species originating from the Ponto-Caspian area colonized the Rhine basin.The yearly minimum and maximum river temperatures at Lobith have increased by circa 4 ℃ over the period 1908-2010.Exotic species show lower PAFs than native species at both ends of the temperature range.The interspecific variation in the temperature tolerance of exotic fish species was found to be large.Using temporal trends in river temperature allowed past predictions of PAFs to demonstrate that the increase in maximum river temperature negatively affected a higher percentage of native fish species than exotic species.Our results support the hypothesis that alterations of the river Rhine's temperature regime caused by thermal pollution and global warming limit the full recovery of native fish fauna and facilitate the establishment of exotic species which thereby increases competition between native and exotic species.Thermal refuges are important for the survival of native fish species under extreme summer or winter temperature conditions [Current Zoology 57 (6):852-862,2011].

  5. Advanced phenotyping offers opportunities for improved breeding of forage and turf species

    DEFF Research Database (Denmark)

    Walter, Achim; Studer, Bruno; Kölliker, Roland

    2012-01-01

    Background and Aims Advanced phenotyping, i.e. the application of automated, high-throughput methods to characterize plant architecture and performance, has the potential to accelerate breeding progress but is far from being routinely used in current breeding approaches. In forage and turf...... improvement programmes, in particular, where breeding populations and cultivars are characterized by high genetic diversity and substantial genotype × environment interactions, precise and efficient phenotyping is essential to meet future challenges imposed by climate change, growing demand and declining...... resources. Scope This review highlights recent achievements in the establishment of phenotyping tools and platforms. Some of these tools have originally been established in remote sensing, some in precision agriculture, while others are laboratory-based imaging procedures. They quantify plant colour...

  6. Associations of Pseudomonas species and forage grasses enhance degradation of chlorinated benzoic acids in soil

    Energy Technology Data Exchange (ETDEWEB)

    Siciliano, S. D.

    1998-12-01

    Using chlorinated benzoic acid (CBA) as a model compound, this study attempted to show that microorganisms and plants can be used as bioremediation agents to clean up contaminated soil sites in a cost effective and environmentally friendly manner. CBA was used because it is present in soils contaminated with polychlorinated biphenyls (PCBs), or chlorinated pesticides. Sixteen forage grasses were screened in combination with 12 bacterial inoculants for their ability to promote the degradation of CBA in soil. Five associations of plants and bacteria were found to degrade CBA to a greater extent than plants without bacterial inoculants. Bacterial inoculants were shown to stimulate CBA degradation by altering the microbial community present on the root surface and thereby increasing the ability of this community to degrade CBA.

  7. Pyrosequencing as a tool for rapid fish species identification and commercial fraud detection.

    Science.gov (United States)

    De Battisti, Cristian; Marciano, Sabrina; Magnabosco, Cristian; Busato, Sara; Arcangeli, Giuseppe; Cattoli, Giovanni

    2014-01-08

    The increased consumption of fish products, as well as the occurrence of exotic fish species in the Mediterranean Sea and in the fish market, has increased the risk of commercial fraud. Furthermore, the great amount of processed seafood products has greatly limited the application of classic identification systems. DNA-based identification allows a clear and unambiguous detection of polymorphisms between species, permitting differentiation and identification of both commercial fraud and introduction of species with potential toxic effects on humans. In this study, a novel DNA-based approach for differentiation of fish species based on pyrosequencing technology has been developed. Raw and processed fish products were tested, and up to 25 species of fish belonging to Clupeiformes and Pleuronectiformes groups were uniquely and rapidly identified. The proper identification based on short and unique genetic sequence signatures demonstrates that this approach is promising and cost-effective for large-scale surveys.

  8. Changes in understory species occurrence of a secondary broadleaved forest after mass mortality of oak trees under deer foraging pressure

    Directory of Open Access Journals (Sweden)

    Hiroki Itô

    2016-12-01

    Full Text Available The epidemic of mass mortality of oak trees by Japanese oak wilt has affected secondary deciduous broadleaved forests that have been used as coppices in Japan. The dieback of oak trees formed gaps in the crown that would be expected to enhance the regeneration of shade-intolerant pioneer species. However, foraging by sika deer Cervus nippon has also affected forest vegetation, and the compound effects of both on forest regeneration should be considered when they simultaneously occur. A field study was conducted in Kyôto City, Japan to investigate how these compound effects affected the vegetation of the understory layer of these forests. The presence/absence of seedlings and saplings was observed for 200 quadrats sized 5 m ×5 m for each species in 1992, before the mass mortality and deer encroachment, and in 2014 after these effects. A hierarchical Bayesian model was constructed to explain the occurrence, survival, and colonization of each species with their responses to the gaps that were created, expanded, or affected by the mass mortality of Quercus serrata trees. The species that occurred most frequently in 1992, Eurya japonica, Quercus glauca, and Cleyera japonica, also had the highest survival probabilities. Deer-unpalatable species such as Symplocos prunifolia and Triadica sebifera had higher colonization rates in the gaps, while the deer-palatable species Aucuba japonica had the smallest survival probability. The gaps thus promoted the colonization of deer-unpalatable plant species such as Symplocos prunifolia and Triadica sebifera. In the future, such deer-unpalatable species may dominate gaps that were created, expanded, or affected by the mass mortality of oak trees.

  9. The effects of turbidity and an invasive species on foraging success of rosyside dace (Clinostomus funduloides)

    Science.gov (United States)

    Peter D. Hazelton; Gary D. Grossman

    2009-01-01

    Habitat degradation and biological invasions are important threats to fish diversity worldwide. We experimentally examined the effects of turbidity, velocity and intra- and interspecific competition on prey capture location, reactive distance and prey capture success of native rosyside dace (Clinostomus funduloides) and invasive yellowfin shiners (Notropis lutipinnis)...

  10. [Species composition and geographical distribution of threatened fishes in Yunnan Province of Southwest China].

    Science.gov (United States)

    Zhang, Qian; Zhong, Jin-Xin

    2013-05-01

    Based on the related published papers, and by using Geographic Information System (ArcGIS 9.3), this paper analyzed the species composition and geographical distribution of threatened fishes in Yunnan Province of Southwest China. There were 83 threatened species living in the Province, belonging to 5 orders, 13 families, and 47 genera. Cypriniformes was absolutely dominant, with 64 species, followed by Siluriformes, with 16 species. Cyprinidae fishes had 51 species, accounting for 79.7% of Cypriniformes. The most species of Cyprinid fishes were of Barbinae (14 species), Cyprininae (10 species), and Cultrinae (10 species). The threatened fishes could be divided into two zoogeographical regions, i. e., Tibetan Plateau region and Oriental region, and their species composition and geographical distribution were resulted from the historical evolution adapted to the related environments. Whatever in rivers and in lakes, the Cyprinid fishes were both absolutely dominant, occupying 36.1% and 31.3% of the total, respectively. The Cyprinid fishes in rivers were mostly of endangered species, while those in lakes were mostly of vulnerable species. The factors affecting the threatened fishes in the Province were discussed from the two aspects of geodynamic evolution and present situation.

  11. Seasonal sexual segregation in two Thalassarche albatross species: competitive exclusion, reproductive role specialization or foraging niche divergence?

    Science.gov (United States)

    Phillips, R A; Silk, J R D; Phalan, B; Catry, P; Croxall, J P

    2004-06-22

    Sexual segregation by micro- or macrohabitat is common in birds, and usually attributed to size-mediated dominance and exclusion of females by larger males, trophic niche divergence or reproductive role specialization. Our study of black-browed albatrosses, Thalassarche melanophrys, and grey-headed albatrosses, T. chrysostoma, revealed an exceptional degree of sexual segregation during incubation, with largely mutually exclusive core foraging ranges for each sex in both species. Spatial segregation was not apparent during brood-guard or post-guard chick rearing, when adults are constrained to feed close to colonies, providing no evidence for dominance-related competitive exclusion at the macrohabitat level. A comprehensive morphometric comparison indicated considerable species and sexual dimorphism in wing area and wing loading that corresponded, both within and between species, to broad-scale habitat preferences relating to wind strength. We suggest that seasonal sexual segregation in these two species is attributable to niche divergence mediated by differences in flight performance. Such sexual segregation may also have implications for conservation in relation to sex-specific overlap with commercial fisheries.

  12. Forage Species Suitability Mapping for China Using Topographic, Climatic and Soils Spatial Data and Quantitative Plant Tolerances

    Institute of Scientific and Technical Information of China (English)

    David B Hannaway; LI Xiang-lin; Christopher Daly; CAO Wei-xing; LUO Wei-hong; WEI Yu-rong; ZHANG Wei-li; XU Ai-guo; LU Chang-ai; SHI Xue-zheng

    2005-01-01

    Selecting plants adapted to the climatic and soil conditions of specific locations is essential for environmental protection and economic sustainability of agricultural and pastoral systems. This is particularly true for countries like China with a diversity of climates and soils and intended uses. Currently, proper species selection is difficult due to the absence of computer-based selection tools. Climate and soil GIS layers, matched with a matrix of plant characteristics through rules describing species tolerances would greatly improve the selection process. Better matching will reduce environmental hazards and economic risks associated with sub-optimal plant selection and performance. GIS-based climate and soil maps have been developed for China. A matrix of quantitative species tolerances has been developed for example forage species and used in combination with an internet map server that allows customized map creation. A web-based decision support system has been developed to provide current information and links to original data sources, supplementary materials, and selection strategies.

  13. Determining spatio-temporal distribution of bee forage species of Al-Baha region based on ground inventorying supported with GIS applications and Remote Sensed Satellite Image analysis

    Directory of Open Access Journals (Sweden)

    Nuru Adgaba

    2017-07-01

    Full Text Available In arid zones, the shortage of bee forage is critical and usually compels beekeepers to move their colonies in search of better forages. Identifying and mapping the spatiotemporal distribution of the bee forages over given area is important for better management of bee colonies. In this study honey bee plants in the target areas were inventoried following, ground inventory work supported with GIS applications. The study was conducted on 85 large plots of 50 × 50 m each. At each plot, data on species name, height, base diameter, crown height, crown diameter has been taken for each plant with their respective geographical positions. The data were stored, and processed using Trimble GPS supported with ArcGIS10 software program. The data were used to estimate the relative frequency, density, abundance and species diversity, species important value index and apicultural value of the species. In addition, Remotely Sensed Satellite Image of the area was obtained and processed using Hopfield Artificial Neural Network techniques. During the study, 182 species from 49 plant families were identified as bee forages of the target area. From the total number of species; shrubs, herbs and trees were accounting for 61%, 27.67%, and 11.53% respectively. Of which Ziziphus spina-christi, Acacia tortilis, Acacia origina, Acacia asak, Lavandula dentata, and Hypoestes forskaolii were the major nectar source plants of the area in their degree of importance. The average vegetation cover values of the study areas were low (<30% with low Shannon’s species diversity indices (H′ of 0.5–1.52 for different sites. Based on the eco-climatological factors and the variations in their flowering period, these major bee forage species were found to form eight distinct spatiotemporal categories which allow beekeepers to migrate their colonies to exploit the resources at different seasons and place. The Remote Sensed Satellite Image analysis confirmed the spatial

  14. ON THE PROBLEM OF REALIZATION THE STRATEGY OF VALUABLE MARKETABLE FISH SPECIES REPRODUCTION IN BASHKORTOSTAN

    OpenAIRE

    2009-01-01

    It is stated that to solve the problem of sufficient food supply for the citizens of our country it is necessary to enhance the development of the fishing industry. The results of the study on the fish and fish products consumer demand in the Republic of Bashkortostan are suggested in the paper. The data obtained allow to substantiate the necessity of the soonest possible realization of the strategy of valuable marketable fish species reproduction in the country.

  15. Locational differences in mercury and selenium levels in 19 species of saltwater fish from New Jersey.

    Science.gov (United States)

    Burger, Joanna; Jeitner, Christian; Gochfeld, Michael

    2011-01-01

    Individuals who fish, and their families that ingest self-caught fish, make decisions about where to fish, what type of fish to eat, and the quantity of fish to eat. While federal and state agencies often issue consumption advisories for some fish with high mercury (Hg) concentrations, advisories seldom provide the actual metal levels to the general public. There are few data for most saltwater fish, and even less information on variations in Hg levels in fish within a state or geographical region. The objective of this study was to provide Hg concentrations from 19 species of fish caught in different locations in New Jersey to (1) test the hypothesis that mean metal levels vary geographically, (2) provide this information to individuals who fish these coastal waters, and (3) provide a range of values for risk assessors who deal with saltwater fish exposure in the Northeastern United States. Selenium (Se) was also examined because of its purported moderating effect on the toxicity of Hg. Hg levels showed significant geographical variation for 10 of 14 species that were caught in more than one region of New Jersey, but there were significant locational differences for Se in only 5 of the fish. Mercury levels were significantly lower in fish collected from northern New Jersey (except for ling, Molva molva), compared to other regions. As might be expected, locational differences in Hg levels were greatest for fish species with the highest Hg concentrations (shark, Isurus oxyrinchus; tuna, Thunnus thynnus and T. albacares; striped bass, Morone saxatilis; bluefish, Pomatomus saltatrix). Fishers and their families might reduce their risk from Hg exposure not only by selecting fish generally lower in Hg, but by fishing predominantly in some regions over others, further lowering the potential risk. Health professionals might use these data to advise patients on which fish are safest to consume (in terms of Hg exposure) from particular geographical regions.

  16. Species List of Alaskan Birds, Mammals, Fish, Amphibians, Reptiles, and Invertebrates. Alaska Region Report Number 82.

    Science.gov (United States)

    Taylor, Tamra Faris

    This publication contains a detailed list of the birds, mammals, fish, amphibians, reptiles, and invertebrates found in Alaska. Part I lists the species by geographical regions. Part II lists the species by the ecological regions of the state. (CO)

  17. Indigenous fish species in the modern ichthyofauna of the Balkhash basin

    Directory of Open Access Journals (Sweden)

    Nadir Shamilevich Mamilov

    2015-11-01

    Full Text Available Indigenous fish fauna of the Balkhash basin was mostly formed in the postglacial period and consists of 10 species from Cyprinidae family, 5 from Balitoridae, and 1 from Percidae. More than 20 alien fish species were introduced here during XXth century that led to eradication of indigenous fishes from the Balkhash Lake and the Ili River. Our investigations of the fish fauna during last 25 years revealed permanent shortage of living area of indigenous fishes. Nowadays fish communities from only indigenous fish species exist in some remote and isolated water bodies. Areas of all indigenous fish species are become disconnected. Reduction of habitats goes relatively slow for naked osman Gymnodiptychus dybowskii (Kessler, 1874, spotted thicklip loach Triplophysa strauchii (Kessler, 1874, and gray loach Triplophysa dorsalis (Kessler, 1872. Drastic reductions of areas were revealed for Ili marinka Schizothorax pseudoaksaiensis Herzenstein 1889, Balkhash marinka Schizothorax argentatus Kessler 1874, Severtsov’s loach Triplophysa sewerzowii (G.Nikolskii, 1938, Seven River’s minnow Phoxinus brachyurus Berg 1912, Balkhsh minnow Rhynchocypris poljakowii Kessler 1879, and Balkhash perch Perca schrenkii Kessler 1874. Marinkas, osmans and perch often become victims of overfishing and poaching of local people. In that region water resources usually are used by wasteful way and loaded with pollutants. Many indigenous fish species are able to bear relatively high level of environment pollution. Hence, the main threats for indigenous fishes are introductions of trout and sander, habitats lose and unstable hydrological regimen.

  18. Jointness through fishing days input in a multi-species fishery

    DEFF Research Database (Denmark)

    Hansen, Lars Gårn; Jensen, Carsten Lynge

    .g. translog, normalized quadratic). In this paper we argue that jointness in the latter, essentially separable fishery is caused by allocation of fishing days input among harvested species. We developed a structural model of a multi-species fishery where the allocation of fishing days input causes production...

  19. Jointness through fishing days input in a multi-species fishery

    DEFF Research Database (Denmark)

    Hansen, Lars Gårn; Jensen, Carsten Lynge

    .g. translog, normalized quadratic). In this paper we argue that jointness in the latter, essentially separable fishery is caused by allocation of fishing days input among harvested species. We developed a structural model of a multi-species fishery where the allocation of fishing days input causes production...

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Christopher M Free

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

  2. Can grey parrots (Psittacus erithacus) succeed on a "complex" foraging task failed by nonhuman primates (Pan troglodytes, Pongo abelii, Sapajus apella) but solved by wrasse fish (Labroides dimidiatus)?

    Science.gov (United States)

    Pepperberg, Irene M; Hartsfield, Leigh Ann

    2014-08-01

    Linking specific cognitive abilities of nonhuman species on a laboratory task to their evolutionary history-ecological niche can be a fruitful exercise in comparative psychology. Crucial issues, however, are the choice of task, the specific conditions of the task, and possibly the subjects' understanding or interpretation of the task. Salwiczek et al. (2012) compared cleaner wrasse fish (Labroides dimidaitus) to several nonhuman primate species (capuchins, Sapajus paella; chimpanzees, Pan troglodytes; orangutans, Pongo abelii) on a task purportedly related to the ecological demands of the fish, but not necessarily of the nonhuman primates; fish succeeded whereas almost all of the nonhuman primates that were tested failed. We replicated the two-choice paradigm of the task with three Grey parrots (Psittacus erithacus), whose ecology, evolutionary history, and cortical capacity are arguably more like those of nonhuman primates than fish. Greys succeeded at levels more like fish than all the nonhuman primates, suggesting possible alternative explanations for their success. Fish and nonhuman primate subjects also experienced a reversal of the initial conditions to test for generalization: Greys were similarly tested; they performed more like fish and capuchins (who now succeeded) than the apes (who continued to fail).

  3. Emerging asymmetric interactions between forage and predator fisheries impose management trade-offs

    DEFF Research Database (Denmark)

    Houle, J.E.; Andersen, Ken Haste; Farnsworth, K.D.;

    2013-01-01

    A size and trait-based marine community model was used to investigate interactions, with potential implications for yields, when a fishery targeting forage fish species (whose main adult diet is zooplankton) co-occurs with a fishery targeting larger-sized predator species. Predicted effects on th...

  4. The Long-Term Effects of Reduced Competitive Ability on Foraging Success of an Invasive Pest Species.

    Science.gov (United States)

    Westermann, Fabian Ludwig; Bell, Vaughn Antony; Suckling, David Maxwell; Lester, Philip John

    2016-08-01

    Ant species like Pheidole megacephala (F.), Solenopsis invicta (Buren), and the Argentine ant, Linepithema humile (Mayr), have repeatedly been reported to be strongly associated with honeydew-producing arthropods like aphids, scale insects, and mealybugs, effectively protecting them from biological control agents like parasitoids. Here we report the results of a successful trial using pheromone dispensers to suppress Argentine ant activity over large sections in a commercial vineyard over a period of two months and preventing ant access into and foraging within the vine canopy. We found Argentine ant activity to be significantly reduced in pheromone-treated plots for the duration of the trial period compared with control plots. Our results showed a significant reduction in the numbers of Argentine ant workers recruited to randomly placed food resources within treated plots compared with untreated plots. Furthermore, spatial distribution of Argentine ants alongside transects in untreated plots remained relatively continuous, while increasing sharply beyond the borders of treated plots. Lastly, we measured the body fat content of workers and found a significant reduction in fat among workers from treated plots compared with untreated plots, suggesting an adverse effects on nest fitness. Additionally, we provide an initial assessment of the feasibility of the presented approach. Our results showed that it is possible to control Argentine ant, preventing them access to and foraging within the vine canopy, thereby reducing Argentine ants' access to honeydew. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Study of the heavy metal phytoextraction capacity of two forage species growing in an hydroponic environment

    Energy Technology Data Exchange (ETDEWEB)

    Bonfranceschi, Barros A. [Centro de Investigacion y Desarrollo en Fermentaciones Industriales (CINDEFI, UNLP-CCT La Plata, CONICET), Facultad de Ciencias Exactas (UNLP), Calle 50 y 115, 1900 La Plata (Argentina); Flocco, C.G. [Consejo Nacional de Investigaciones Cientificas y Tecnologicas (CONICET), Buenos Aires (Argentina); Donati, E.R., E-mail: donati@quimica.unlp.edu.ar [Centro de Investigacion y Desarrollo en Fermentaciones Industriales (CINDEFI, UNLP-CCT La Plata, CONICET), Facultad de Ciencias Exactas (UNLP), Calle 50 y 115, 1900 La Plata (Argentina)

    2009-06-15

    Sorghum and alfalfa are two important forage crops. We studied their capacity for accumulating heavy metals in hydroponic experiments. Cadmium, nickel (as divalent cations) and chromium (trivalent and hexavalent) were added individually to the nutrient solution in a range of concentrations from 1 to 80 mg/l. Cr(III) was complexed with EDTA to increase its bioavailability. In alfalfa the increases in the concentration of Cr(III) and Cr(VI) favoured translocation of the metals to the upper parts of the plants, while with Ni(II) the level of translocated metal remained almost unchanged. In sorghum, both Cr(VI) and Ni(II) produced similar results to those in alfalfa, but increases in the concentrations of Cd(II) and Cr(III) in the solution lead to a higher accumulation of the metal at the root level. The concentrations referred to the dry biomass of alfalfa were 500 mg/kg (aerial parts) and 1500 mg/kg (roots) of Cr(III), simultaneously enhancing plant growth. Sorghum captured 500 and 1100 mg/kg (in aerial parts) and 300 and 2000 mg/kg (in roots) for Ni(II) and Cd(II) respectively, without significant damage to its biomass. The results show that alfalfa and sorghum can not only grow in the presence of high heavy metal concentration but also capture and translocate them to the aerial parts; because of these results special attention should be given to these crop plants for their possible use in phytoremediation of large contaminated areas but especially to avoid the possible introduction of the metals accumulated in aerial parts into the food chain when those plants grow in contaminated areas.

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

    Science.gov (United States)

    Kellnreitner, Florian; Pockberger, Moritz; Asmus, Harald

    2012-08-01

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

  7. Total mercury levels in commercial fish species from Italian fishery and aquaculture.

    Science.gov (United States)

    Di Lena, Gabriella; Casini, Irene; Caproni, Roberto; Fusari, Andrea; Orban, Elena

    2017-01-29

    Total mercury levels were measured in 42 commercial fish species caught off the Central Adriatic and Tyrrhenian coasts of Italy and in 6 aquaculture species. The study on wild fish covered species differing in living habitat and trophic level. The study on farmed fish covered marine and freshwater species from intensive and extensive aquaculture and their feed. Mercury levels were analysed by thermal decomposition-amalgamation-atomic absorption spectrophotometry. Total mercury concentrations in the muscle of wild fish showed a high variability among species (0.025-2.20 mg kg(-1) wet weight). The lowest levels were detected in low trophic-level demersal and pelagic-neritic fish and in young individuals of high trophic-level species. Levels exceeding the European Commission limits were found in large-size specimens of high trophic-level pelagic and demersal species. Fish from intensive farming showed low levels of total mercury (0.008-0.251 mg kg(-1)). Fish from extensive rearing showed variable contamination levels, depending on the area of provenience. An estimation of the human intake of mercury associated to the consumption of the studied fish and its comparison with the tolerable weekly intake is provided.

  8. Effects of forest fertilization on nitrate and crude protein content in some important reindeer forage species

    Directory of Open Access Journals (Sweden)

    Gustaf Åhman

    1984-05-01

    Full Text Available When forests are fertilized with ammonia nitrate it is possible that grazing reindeer ingest ammonia nitrate by eating grains of fertilizer from the ground or by drinking contaminated water. They can also get nitrate through plants that have absorbed and disposed nitrate. This latter factor is studied in this report. In addition the effect of fertilization on crude protein content in forage plants is investigated. Fertilizing trials were done within two different areas. One was a dry scotch pine forest and the other a humid scotch pine forest. Both were situated 10 to 15 km north west of Lycksele (northern Sweden. Three different rations (75, 150 and 250 kg N/ha of ammonianitrate and one (150 kg N/ha of urea was used. Fertilization was done at two occations, in June and in July. To investigate the effect of fertilization on nitrate and crude protein content in reindeer forage plants, samples were taken of reindeer lichens (Cladina spp., heather {Calluna vulgaris, crowberry (Empetrum spp., cowberry (Vaccinium vitis ideae, blueberry (Vaccinium myrtillus and hair-grass (Deschampsia flexuosa at different times after fertilization. In this trial we could not find any higher degree of contamination of nitrate in lichens. The highest value was 0.013% nitrate-N in dry matter (table 1. Nitrate accumulation was low in shrubs and grass (table 2. The highest value (0.05% was found in heather. The concentrations were definitly below the level that could be considered as injurious to the reindeer. The effect of fertilization on crude protein content in reindeer forage plants was obvious. It was most evident in hair-grass. Four weeks after fertilization with 150 kg N/ha, crude protein content was more than doubled and reached 20% in dry matter (figure 1 and 2. In withered hair-grass in the autumn the effect was very small. One year after fertilization a small rise in crude protein was registered in both grass and shrubs (table 3. Some effect still remained

  9. Explorations on Temperature, Oxygen, Nutrients and Habitat Demands of Fish Species Found in River Coruh

    Directory of Open Access Journals (Sweden)

    Bilal Akbulut

    2009-04-01

    Full Text Available For the protection of our natural resources, fish species being economic and ecological richness of the natural in the basin of the Çoruh to know their request is extremely a vital important issue. In this study, temperature and oxygen demand, food and habitat of 18 fish species in six families found in river Çoruh assessed and discussed with the literature and database. Limiting the impact of water temperature on the reproductive, growth and nutrition emphasized. The fish species in the basin spawn at temperatures between 14-30°C according to database. Three species belonging to a family feed with animal food floating in the water. The species belonging to the other families more feed mixed with plant and animal foods diet in the floor or near the ground. Importance of their environmental demands has clarified for conservation and sustainable use of these fish species inhabiting in Çoruh River.

  10. Fishes and other aquatic species in the Byzantine literature. Classification, terminology and scientific names.

    Directory of Open Access Journals (Sweden)

    Maria CHRONE-VAKALOPOULOS

    2009-01-01

    Full Text Available Fishes and other aquatic species were substantial food in the every day life of Byzantine people. The predomination of Christianity contributed to the increased consumption of fishes and other seafood compared to the meat of land animals and chicken. More than a hundred ten names of fishes and about thirty names of other aquatic organisms are found in the sources of the Byzantine literature. Most frequent references are found in the medical texts of the Byzantine doctors, where, fishes are classified in categories depending on their physiology and origin, because, according to the writers, these are determining factors for the evaluation of the nutritional value of each species.The purpose of this study is to present the terminology of the fishes and the various aquatic species that are found in the Byzantine sources and to identify, in parallel, each species with its current scientific name.  

  11. Energetic cost of foraging in free-diving emperor penguins.

    Science.gov (United States)

    Nagy, K A; Kooyman, G L; Ponganis, P J

    2001-01-01

    Hypothesizing that emperor penguins (Aptenodytes forsteri) would have higher daily energy expenditures when foraging for their food than when being hand-fed and that the increased expenditure could represent their foraging cost, we measured field metabolic rates (FMR; using doubly labeled water) over 4-d periods when 10 penguins either foraged under sea ice or were not allowed to dive but were fed fish by hand. Surprisingly, penguins did not have higher rates of energy expenditure when they dove and captured their own food than when they did not forage but were given food. Analysis of time-activity and energy budgets indicated that FMR was about 1.7 x BMR (basal metabolic rate) during the 12 h d(-1) that penguins were lying on sea ice. During the remaining 12 h d(-1), which we termed their "foraging period" of the day, the birds were alert and active (standing, preening, walking, and either free diving or being hand-fed), and their FMR was about 4.1 x BMR. This is the lowest cost of foraging estimated to date among the eight penguin species studied. The calculated aerobic diving limit (ADL(C)), determined with the foraging period metabolic rate of 4.1 x BMR and known O(2) stores, was only 2.6 min, which is far less than the 6-min ADL previously measured with postdive lactate analyses in emperors diving under similar conditions. This indicates that calculating ADL(C) from an at-sea or foraging-period metabolic rate in penguins is not appropriate. The relatively low foraging cost for emperor penguins contributes to their relatively low total daily FMR (2.9 x BMR). The allometric relationship for FMR in eight penguin species, including the smallest and largest living representatives, is kJ d(-1)=1,185 kg(0.705).

  12. Optimising invasive fish management in the context of invasive species legislation in South Africa

    OpenAIRE

    Woodford, Darragh J.; Phillip Ivey; Jordaan, Martine S.; Peter K. Kimberg; Tsungai Zengeya; Olaf L.F. Weyl

    2017-01-01

    Background: South Africa hosts a large number of non-native freshwater fishes that were introduced for various industries. Many of these species are now listed under the National Environmental Management: Biodiversity Act (NEM:BA) Alien and Invasive Species (A&IS) lists and regulations, though the practical options available to conservation agencies to effectively manage these fishes vary greatly among species and regions. Objectives & methods: We assessed the history and status of na...

  13. Life history strategies of fish species and biodiversity in eastern USA streams

    Science.gov (United States)

    Meador, Michael R.; Brown, Larry M.

    2015-01-01

    Predictive models have been used to determine fish species that occur less frequently than expected (decreasers) and those that occur more frequently than expected (increasers) in streams in the eastern U.S. Coupling life history traits with 51 decreaser and 38 increaser fish species provided the opportunity to examine potential mechanisms associated with predicted changes in fish species distributions in eastern streams. We assigned six life history traits – fecundity, longevity, maturation age, maximum total length, parental care, and spawning season duration – to each fish species. Decreaser species were significantly smaller in size and shorter-lived with reduced fecundity and shorter spawning seasons compared to increaser species. Cluster analysis of traits revealed correspondence with a life history model defining equilibrium (low fecundity, high parental care), opportunistic (early maturation, low parental care), and periodic (late maturation, high fecundity, low parental care) end-point strategies. Nearly 50 % of decreaser species were associated with an intermediate opportunistic-periodic strategy, suggesting that abiotic factors such as habitat specialization and streamflow alteration may serve as important influences on life history traits and strategies of decreaser species. In contrast, the percent of increaser species among life history strategy groups ranged from 21 to 32 %, suggesting that life history strategies of increaser species were more diverse than those of decreaser species. This study highlights the utility of linking life history theory to biodiversity to better understand mechanisms that contribute to fish species distributions in the eastern U.S.

  14. Foraging activity and seasonal food preference of Linepithema micans (Hymenoptera: Formicidae), a species associated with the spread of Eurhizococcus brasiliensis (Hemiptera: Margarodidae).

    Science.gov (United States)

    Nondillo, Aline; Ferrari, Leonardo; Lerin, Sabrina; Bueno, Odair Correa; Bottona, Marcos

    2014-08-01

    Linepithema micans (Forel) (Hymenoptera: Formicidae) is the main ant species responsible for the spread of Eurhizococcus brasiliensis (Wille) (Hemiptera: Margarodidae), a soil scale that damages vine plants in southern Brazil. The daily foraging activity of L. micans and its seasonal preference for protein- and carbohydrate-based foods were evaluated. The study was carried out in a greenhouse using seedlings of the Paulsen 1103 rootstock (Vitis berlandieri x Vitis rupestris) planted individually in pots and infested with colonies of L. micans. To determine the daily foraging activity and seasonal preference, a cricket (Gryllus sp.) and a 70% solution of inverted sugar and water were offered once a month for 12 mo. The ants foraging on each food source were counted hourly for 24 h. L. micans foraged from dusk until the end of the next morning, with higher intensity in the spring and summer. Workers of L. micans showed changes in food preference during the year, with a predominance of protein-based food during winter and spring and carbohydrate-based food during autumn. The implications of this behavior for control of the species with the use of toxic baits are discussed.

  15. Experimental study to control the upstream migration of invasive alien fish species by submerged weir

    Science.gov (United States)

    Sakuma, Masami; Kunimatsu, Fumihiro; Tsuchiya, Taku; Kawamura, Makiko; Fujita, Hiroshi

    Largemouth bass and Bluegill, major invasive alien fish species in Japan, have been extending their habitat ranges over not only Lake Biwa and the lagoons but also surrounding waters connected to them through small rivers and canals. Their increasing number is bringing about the reduction in the number of native fish species. To prevent the spread of these alien species through small rivers and canals during breeding season of the native fish (crucian carp), this study experimentally examined the effect of a submerged weir on controlling upstream migration of the alien species and the native fish. As a result of the experiment, the ratio of the alien species migrating upstream decreased as the weir height rose, whereas the ratio did not show the same trend in the case of the native fish. The ratio of the alien species also decreased as the overflow velocity over the weir rose. On the other hand, the ratio of the native fish increased as the overflow velocity rose up to 1.0m/s and decreased thereafter. These results suggest that the submerged weir may control upstream migration of the alien species to surrounding waters through small rivers and canals without interfering with the reproductive migration of the native fish.

  16. Is There a Relationship between Fish Cannibalism and Latitude or Species Richness?

    Science.gov (United States)

    Pereira, Larissa Strictar; Keppeler, Friedrich Wolfgang; Agostinho, Angelo Antonio; Winemiller, Kirk O

    2017-01-01

    Cannibalism has been commonly observed in fish from northern and alpine regions and less frequently reported for subtropical and tropical fish in more diverse communities. Assuming all else being equal, cannibalism should be more common in communities with lower species richness because the probability of encountering conspecific versus heterospecific prey would be higher. A global dataset was compiled to determine if cannibalism occurrence is associated with species richness and latitude. Cannibalism occurrence, local species richness and latitude were recorded for 4,100 populations of 2,314 teleost fish species. Relationships between cannibalism, species richness and latitude were evaluated using generalized linear mixed models. Species richness was an important predictor of cannibalism, with occurrences more frequently reported for assemblages containing fewer species. Cannibalism was positively related with latitude for both marine and freshwater ecosystems in the Northern Hemisphere, but not in the Southern Hemisphere. The regression slope for the relationship was steeper for freshwater than marine fishes. In general, cannibalism is more frequent in communities with lower species richness, and the relationship between cannibalism and latitude is stronger in the Northern Hemisphere. In the Southern Hemisphere, weaker latitudinal gradients of fish species richness may account for the weak relationship between cannibalism and latitude. Cannibalism may be more common in freshwater than marine systems because freshwater habitats tend to be smaller and more closed to dispersal. Cannibalism should have greatest potential to influence fish population dynamics in freshwater systems at high northern latitudes.

  17. Effects of Water Pollution in Koluama Area, Niger Delta Area, Nigeria Fish Species Composition, Histology, Shrimp Fishery and Fishing Gear Type

    National Research Council Canada - National Science Library

    J.F.N. Abowei; E.N. Ogamba

    2013-01-01

    The effect of water pollution in Koluama Area in the Niger Delta region of Nigeria to determine its effects on fish species composition, histology, shrimp fishery and fishing gear type. A total of twenty (20...

  18. Effects of reserve protection level on the vulnerable fish species Sciaena umbra and implications for fishing management and policy

    Directory of Open Access Journals (Sweden)

    Mireille Harmelin-Vivien

    2015-01-01

    Full Text Available The brown meagre Sciaena umbra, an iconic demersal fish species in Mediterranean coastal habitats, is particularly vulnerable to fishing pressure and presents a worrying population decline. Fish numbers and sizes were surveyed by visual census at Scandola (Corsica in and outside reserve zones subject to increasing levels of protection, including unprotected zones (UP where all fishing activities are permitted, buffer zones (BZ subject to partial protection and a totally protected no-take integral reserve zone (IR. The numerical abundance, individual size and biomass of the brown meagre were found to increase with levels of reserve protection. The abundance of the larger size classes and the numbers of fish per shoal were significantly lower in unprotected zones. A comparison with similar censuses performed in 1983 showed a significant increase of S. umbra abundance in IR, but no difference in UP. That increasing levels of protection resulted in increased abundance and biomass of the brown meagre suggested a prominent role of fishing, particularly spearfishing, activities in the persistence of its low abundance in the unprotected zones. As a consequence, protective action for the brown meagre (including a ban on both spearfishing and recreational hook-and-line fishing has been introduced in France since January 2014.

  19. Species persistence: a re-look at the freshwater fish fauna of Chennai, India

    Directory of Open Access Journals (Sweden)

    J.D.M. Knight

    2010-11-01

    Full Text Available Loss of habitat is one of the prime reasons for species extinction. It is generally established that certain classes of animals are more prone to extinction than others due to their restricted use of available habitats. Freshwater fish are among these sensitive animals. While local extinctions have rendered some species rare throughout their geographical range, many others have demonstrated higher levels of persistence. This paper focuses on a recent in-depth study of the primary freshwater fishes in and around Chennai. The study that spanned a period of two years recorded a total of 75 species of primary freshwater fish, of which 17 are new reports.

  20. The diet and consumption of dominant fish species in the upper Scheldt estuary, Belgium

    DEFF Research Database (Denmark)

    Maes, J.; De Brabandere, Loreto; Ollevier, F.

    2003-01-01

    Seasonal changes in the diet composition and trophic niche overlap were examined for the dominant members of the fish assemblage of the turbid low-salinity zone of the Scheldt estuary (Belgium). Samples of fish were taken in the cooling water of a power plant. Juveniles of eight species dominated...... of trophic niche overlap showed that, in general, niche overlap between individuals of the same species was significantly higher than overlap between individuals from different species, suggesting that the available food resources were partitioned. The total annual prey consumption by the dominant fish...

  1. total mercury distribution in different fish species representing ...

    African Journals Online (AJOL)

    DEPT OF AGRICULTURAL ENGINEERING

    tion; and suggest a relatively clean marine environment that has not yet been significantly im- ..... Positive relationship between fish mercury ... tion was reported for tuna which is a carnivore ... duce the effect of variable size composition of.

  2. Threatened and Endangered Freshwater Fish and Mussel Species Richness

    Data.gov (United States)

    U.S. Environmental Protection Agency — These data represent predicted current distributions of all US listed Threatened and Endangered freshwater fish and freshwater mussels in the Middle-Atlantic region....

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Elena L.E.S. Wagner

    2015-12-01

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

  5. Foraging ecology of least terns and piping plovers nesting on Central Platte River sandpits and sandbars

    Science.gov (United States)

    Sherfy, Mark H.; Anteau, Michael J.; Shaffer, Terry L.; Sovada, Marsha A.; Stucker, Jennifer H.

    2012-01-01

    Federally listed least terns (Sternula antillarum) and piping plovers (Charadrius melodus) nest on riverine sandbars on many major midcontinent river systems. On the Central Platte River, availability of sandbar habitat is limited, and both species nest on excavated sandpits in the river's floodplain. However, the extent to which sandpit-nesting birds use riverine habitats for foraging is unknown. We evaluated use of foraging habitats by least terns and piping plovers by collecting data on movements, behavior, foraging habitat, and productivity. We radiomarked 16 piping plovers and 23 least terns in 2009-2010 and monitored their movements using a network of fixed telemetry dataloggers. Piping plovers were detected primarily by the datalogger located in their nesting sandpit, whereas least terns were more frequently detected on dataloggers outside of the nesting sandpit. Telemetry data and behavioral observations showed that least terns tended to concentrate at the Kearney Canal Diversion Gates, where forage fish were apparently readily available. Fish sampling data suggested that forage fish were more abundant in riverine than in sandpit habitats, and behavioral observations showed that least terns foraged more frequently in riverine than in sandpit habitats. Piping plovers tended to forage in wet substrates along sandpit shorelines, but also used dry substrates and sandpit interior habitats. The greater mobility of least terns makes a wider range of potential foraging habitats available during brood rearing, making them able to exploit concentrations of fish outside the nesting colony. Thus, our data suggest that different spatial scales should be considered in managing nesting and foraging habitat complexes for piping plovers and least terns.

  6. Nitrogen transfer from forage legumes to nine neighbouring plants in a multi-species grassland

    DEFF Research Database (Denmark)

    Pirhofer-Walzl, Karin; Høgh Jensen, Henning; Eriksen, Jørgen

    2012-01-01

    Legumes play a crucial role in nitrogen supply to grass-legume mixtures for ruminant fodder. To quantify N transfer from legumes to neighbouring plants in multi-species grasslands we established a grass-legume-herb mixture on a loamy-sandy site in Denmark. White clover (Trifolium repens L.), red...... amounts of N from legumes than dicotyledonous plants which generally have taproots. Slurry application mainly increased N transfer from legumes to grasses. During the growing season the three legumes transferred approximately 40 kg N ha-1 to neighbouring plants. Below-ground N transfer from legumes...

  7. Survey of fungal infestation of some fish species from Tagwai dam, Minna, Niger State

    OpenAIRE

    Tsadu, S.M.; Ojutiku, R.O.; Ayanwale, A.V.

    2005-01-01

    Survey of Fungal infestation of some species of fish in Tagwai Dam Minna was carried out from March to June 2002. Fungi were isolated from the scale/skin, gills and fins. Twenty-one fungi species were identified from 18 species of fish microbial growth was measured by direct cell count using Stuart colony counter. Most of the fungi encountered were of the mould group and infestation occurred among all the species sampled. The infestation was predominantly by Aspergillus species and the scale/...

  8. Foraging behaviors of two sympatric ant species in response to lizard eggs.

    Science.gov (United States)

    Huang, Wen-San

    2010-03-01

    The trade-off between behavioral dominance and resource discovery ability represents a mechanism which could facilitate the coexistence of species, but evidence of the existence of this trade-off is limited and is often derived from experiments using artificial bait. In this study, I performed a field experiment to investigate the outcome of potential food competition between an encounter species (Paratrechina longicornis) and an exploitative one (Pheidole taivanensis) and to examine the factors that may explain the behavior of P. taivanensis when obtaining food (lizard eggs) without being attacked by P. longicornis. When P. longicornis was experimentally introduced to eggs occupied by P. taivanensis for 1 day, it displaced P. taivanensis. However, P. longicornis ignored lizard eggs which had been occupied by P. taivanensis for 2 or more days, and did not displace P. taivanensis, because by that time the eggshells had been damaged by P. taivanensis so they could no longer be used by P. longicornis. Eggshells were damaged more quickly by P. taivanensis at Santimen, southwestern Taiwan, than at four other study sites where there were lower intensities of food competition between P. taivanensis and P. longicornis. The displacement percentage was higher at Santimen which had higher ant population densities. The present study shows that lizard eggs may constitute a natural, ephemeral resource for which ants compete in space and time. Comparisons between study sites with and without ants suggest the existence of a trade-off between resource discovery and territorial defense.

  9. 77 FR 67794 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2012-11-14

    ... mechanisms that affect growth at these life stages. During the mid- water trawls, the fish would be... identified by species and measured, have a tissue sample taken (to determine their origin), and be released... salmonid populations. The UW proposes capturing fish by mid-water trawl, beach seine, and purse seine. The...

  10. 76 FR 67121 - Atlantic Highly Migratory Species; 2012 Atlantic Shark Commercial Fishing Season

    Science.gov (United States)

    2011-10-31

    ... Species; 2012 Atlantic Shark Commercial Fishing Season AGENCY: National Marine Fisheries Service (NMFS... season for the Atlantic commercial shark fisheries. Quotas would be adjusted based on any over- and/or underharvests experienced during the 2010 and 2011 Atlantic commercial shark fishing seasons. In addition,...

  11. 78 FR 52487 - Atlantic Highly Migratory Species; 2014 Atlantic Shark Commercial Fishing Season

    Science.gov (United States)

    2013-08-23

    ... Species; 2014 Atlantic Shark Commercial Fishing Season AGENCY: National Marine Fisheries Service (NMFS... season for the Atlantic commercial shark fisheries. Quotas would be adjusted as allowable based on any..., fishing opportunities for commercial shark fishermen in all regions and areas. The proposed measures...

  12. 76 FR 27017 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2011-05-10

    ... and migration. Monitoring the restoration sites will help determine the projects' effectiveness and... the species by removing existing human-made fish barriers or possibly replacing them with structures... monitor the effects of recovery actions. The NMFSC would capture fish on a monthly basis using a...

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

    Directory of Open Access Journals (Sweden)

    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.

  14. 75 FR 76302 - Atlantic Highly Migratory Species; 2011 Commercial Fishing Season and Adaptive Management...

    Science.gov (United States)

    2010-12-08

    ... Species; 2011 Commercial Fishing Season and Adaptive Management Measures for the Atlantic Shark Fishery... currently affecting management of the shark fishery, including commercial landings that exceed the quotas... and 2010 Atlantic commercial shark fishing seasons. NMFS is taking this action to establish the...

  15. Connecting ground water influxes with fish species diversity in an urbanized watershed

    Science.gov (United States)

    Steffy, L.Y.; McGinty, A.L.; Welty, C.; Kilham, S.S.

    2004-01-01

    Valley Creek watershed is a small stream system that feeds the Schuylkill River near Philadelphia, Pennsylvania. The watershed is highly urbanized, including over 17 percent impervious surface cover (ISC) by area. Imperviousness in a watershed has been linked to fish community structure and integrity. Generally, above 10 to 12 percent ISC there is marked decline in fish assemblages with fish being absent above 25 percent ISC. This study quantifies the importance of ground water in maintaining fish species diversity in subbasins with over 30 percent ISC. Valley Creek contains an atypical fish assemblage in that the majority of the fish are warm-water species, and the stream supports naturally reproducing brown trout, which were introduced and stocked from the early 1900s to 1985. Fish communities were quantified at 13 stations throughout the watershed, and Simpson's species diversity index was calculated. One hundred and nine springs were located, and their flow rates measured. A cross covariance analysis between Simpson's species diversity index and spring flow rates upstream of fish stations was performed to quantify the spatial correlation between these two variables. The correlation was found to be highest at lag distances up to about 400 m and drop off significantly beyond lag distances of about 800 m.

  16. Multiplexed identification of different fish species by detection of parvalbumin, a common fish allergen gene: a DNA application of multi-analyte profiling (xMAP) technology.

    Science.gov (United States)

    Hildebrandt, Sabine

    2010-07-01

    Fish are a common cause of allergic reactions associated with food consumption, with parvalbumin being the major allergenic protein. Some fish-hypersensitive patients tolerate some fish species while being allergic to others. Reliable detection methods for allergenic fish species in foods are necessary to ensure compliance with food allergen labeling guidelines to protect fish-allergic consumers. The objective of this project was to develop a multi-analyte detection method for the presence of fish in food. Therefore, conserved parvalbumin exon sequences were utilized for the design of universal PCR primers amplifying intron DNA and small regions of exons flanking the enclosed intron from even very distantly related fish species. An assay for the identification of eight fish species was developed using xMAP technology with probes targeting species-specific parvalbumin intron regions. Additionally, a universal fish probe was designed targeting a highly conserved exon region located between the intron and the reverse primer region. The universal fish assay showed no cross-reactivity with other species, such as beef, pork, lamb, chicken, turkey, and shrimp. Importantly, with the exception of one notable case with fish in the same subfamily, species-specific detection showed no cross-reactivity with other fish species. Limits of detection for these eight species were experimentally estimated to range from 0.01% to 0.04%, with potential to increase the detection sensitivity. This report introduces a newly developed method for the multiplex identification of at least eight allergenic fish species in food, which could conceivably be extended to detect up to 100 species simultaneously in one sample.

  17. Spawning and nursery habitats of neotropical fish species in the tributaries of a regulated river

    Science.gov (United States)

    Makrakis, Maristela Cavicchioli; da Silva, Patrícia S.; Makrakis, Sergio; de Lima, Ariane F.; de Assumpção, Lucileine; de Paula, Salete; Miranda, Leandro E.; Dias, João Henrique Pinheiro

    2012-01-01

    This chapter provides information on ontogenetic patterns of neotropical fish species distribution in tributaries (Verde, Pardo, Anhanduí, and Aguapeí rivers) of the Porto Primavera Reservoir, in the heavily dammed Paraná River, Brazil, identifying key spawning and nursery habitats. Samplings were conducted monthly in the main channel of rivers and in marginal lagoons from October through March during three consecutive spawning seasons in 2007-2010. Most species spawn in December especially in Verde River. Main river channels are spawning habitats and marginal lagoons are nursery areas for most fish, mainly for migratory species. The tributaries have high diversity of larvae species: a total of 56 taxa representing 21 families, dominated by Characidae. Sedentary species without parental care are more abundant (45.7%), and many long-distance migratory fish species are present (17.4%). Migrators included Prochilodus lineatus, Rhaphiodon vulpinus, Hemisorubim platyrhynchos, Pimelodus maculatus, Pseudoplatystoma corruscans, Sorubim lima, two threatened migratory species: Salminus brasiliensis and Zungaro jahu, and one endangered migratory species: Brycon orbignyanus. Most of these migratory species are vital to commercial and recreational fishing, and their stocks have decreased drastically in the last decades, attributed to habitat alteration, especially impoundments. The fish ladder at Porto Primavera Dam appears to be playing an important role in re-establishing longitudinal connectivity among critical habitats, allowing ascent to migratory fish species, and thus access to upstream reaches and tributaries. Establishment of Permanent Conservation Units in tributaries can help preserve habitats identified as essential spawning and nursery areas, and can be key to the maintenance and conservation of the fish species in the Paraná River basin.

  18. [Identification of fish species based on ribosomal DNA ITS2 locus].

    Science.gov (United States)

    Yuan, Wan-An

    2010-04-01

    To prevent illegal fishing and sale, the most difficult problem is identification of marketed fish species, especially the parts that are difficult to be differentiated with morphological method (e.g., larval, eggs, scales, meat, products etc. To assist conservation and management of fishery resources, this paper reported a molecular genetic approach based on ribosomal internal transcribed spacer 2 locus. The method includes two steps: (1) the order general primers were designed according to the conservative nature of 5.8SrRAN and 28SrRNA genes within an order, and the DNA ribosomal internal transcribed spacer 2 locus fragment were then amplified and sequenced. (2) The species-specific ladders and the species-specific primers for each species were designed according to the sequencing results. The map of molecular taxonomy was constructed. This approach employs multiplex PCR that is formatted for fish species identification. We tested 210 single-species samples and 40 mix-species samples from different regions of China. The approach distinguished accurately and sensitively samples from each of the five species. This genetic and molecular approach will be useful for fish conservation, assessment, management and exploitation, strengthen in law enforcement of fishery manager, combat rare and endangered fish smuggling, and prevent commercial fraud and biological invasion by harmful nonnative species.

  19. Paternity Testing, a Poor Man’s Marker Assisted Breeding Strategy to Increase Selection Gains in Outbred Forage Species

    Science.gov (United States)

    Many methods to incorporate molecular markers into breeding programs have been proposed. Most existing marker assisted selection strategies use selection based on molecular marker linkage to achieve selection gains. Such strategies are often prohibitively expensive in forage breeding (Riday, 2007)...

  20. Endangered Species Consultation Request : Opening to Sports & Commercial Fishing Ottawa and Cedar Point NWR’s

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Endangered Species Consultation Request states that the Ottawa and Cedar Point NWRs Fishery Management Plan will not affect bald eagles on the Refuge.

  1. Petroleum hydrocarbon concentration in selected species of fish and prawn form northwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Mehta, P.; Kadam, A.N.; Gajbhiye, S.N.; Desai, B.N.

    Concentration of petroleum hydrocarbons in 6 fish and prawn species sampled at 10 transects from Veraval to Ratnagiri were determined using alkali digestion and alumina column chromatography followed by fluorescence spectroscopy. Efficiency...

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

    Science.gov (United States)

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

    2016-04-30

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

  3. Florida Reef Fish Visual Census 1994 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  4. Florida Reef Fish Visual Census 1997 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  5. Florida Reef Fish Visual Census 1984 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  6. Florida Reef Fish Visual Census 1987 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  7. Florida Reef Fish Visual Census 1988 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  8. Florida Reef Fish Visual Census 1991 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  9. Florida Reef Fish Visual Census 1998 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  10. Florida Reef Fish Visual Census 1979 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  11. Florida Reef Fish Visual Census 1993 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  12. Florida Reef Fish Visual Census 1981 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  13. Florida Reef Fish Visual Census 1986 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  14. Florida Reef Fish Visual Census 1992 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  15. Florida Reef Fish Visual Census 1982 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  16. Florida Reef Fish Visual Census 1995 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  17. Florida Reef Fish Visual Census 1985 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  18. Florida Reef Fish Visual Census 1990 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  19. Florida Reef Fish Visual Census 1980 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  20. Florida Reef Fish Visual Census 1996 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  1. Florida Reef Fish Visual Census 1983 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  2. Florida Reef Fish Visual Census 1989 Species Site Matrix (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida Keys. The...

  3. [Invertebrate species variety and quantity for selected units, Fish Springs NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this survey was to determine if invertebrate species diversity and abundance were affected by a draw down. It was concluded that there was an inverse...

  4. A Record of Small-Clawed Otters (Aonyx cinereus) Foraging on an Invasive Pest Species, Golden Apple Snails (Pomacea canaliculata) in a West Sumatra Rice Field

    OpenAIRE

    Jabang; Wilson Novarino; Aadrean

    2011-01-01

    A small-clawed otter (Aonyx cinereus) survey in West Sumatran rice fields was conducted from April to September 2010. During this survey, golden apple snail (Pomacea canaliculata) shell remains were found on a rice field bank as suspected prey remains of small-clawed otters. This suspicion was later proved by the occurrence of snail material (pieces of operculum and shell) in otter spraints. This is the first evidence of small-clawed otters foraging on this invasive pest species. Characterist...

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

    Science.gov (United States)

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

    2006-07-01

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

  6. Levels of genetic diversity and taxonomic status of Epinephelus species in United Arab Emirates fish markets.

    Science.gov (United States)

    Ketchum, Remi N; Dieng, Mame M; Vaughan, Grace O; Burt, John A; Idaghdour, Youssef

    2016-04-30

    Understanding the patterns of genetic diversity of fish species is essential for marine conservation and management. This is particularly important in the Arabian Gulf where marine life is subject to extreme environmental conditions that could impact genetic diversity. Here we assess genetic diversity of the most commercially important fish in the United Arab Emirates; groupers (Epinephelus spp.). Sequencing of 973 bp mitochondrial DNA from 140 tissue samples collected in four main fish markets revealed 58 haplotypes clustered within three groups. Data analysis revealed the presence of three distinct Epinephelus species being marketed as one species (hammour): Epinephelus coioides, Epinephelus areolatus and Epinephelus bleekeri. We report species-specific genetic markers and demonstrate that all three species exhibit relatively low levels of genetic variation, reflecting the effect of overfishing and environmental pressures. In light of the genetic evidence presented here, conservation and management of groupers in the UAE warrant the implementation of species-specific measures.

  7. Nitrogen and carbohydrate fractions in exclusive Tifton 85 and in pasture oversown with annual winter forage species - 10.4025/actascianimsci.v34i1.11428

    Directory of Open Access Journals (Sweden)

    Ana Claudia Ruggieri

    2011-11-01

    Full Text Available The experiment was undertaken at the Faculty of Agrarian and Veterinary Sciences (FCAV Jaboticabal, São Paulo State, Brazil, during winter-spring-summer of 2001-2002, to determine the fractionation of nitrogen and carbohydrates in Tifton 85 (Cynodon dactylon Vanderyst x Cynodon nlemfuensis (L. Pers, exclusively or oversown with winter annual forage species. Treatments comprised bristle oat (Avena strigosa Schreb, yellow oat (Avena byzantina C. Koch, triticale (X Triticosecale Wittmack, bristle oat + yellow oat, bristle oat + triticale, yellow oat + triticale, bristle oat + yellow oat + triticale seeded in Tifton 85 and sole crop (control. Experimental design was composed of completely randomized blocks with three replications. Fodder was cut 20 cm high (presence of winter forage and 10 cm high (Tifton 85 pasture. Crude protein, total carbohydrate and the fractions of nitrogen compounds and carbohydrates were determined. Decrease was reported in the levels of chemical compounds in winter forage species and in Tifton 85 during the evaluation periods. The content of nitrogen compounds and carbohydrates varied widely during the evaluation period according to the morphological characteristics of grass species and botanical composition of pastures.

  8. Flowering, pollen characteristics and insect foraging on Campanula bononiensis (Campanulaceae, a protected species in Poland

    Directory of Open Access Journals (Sweden)

    Bożena Denisow

    2014-07-01

    Full Text Available This study investigated the floral biology and pollen quantity and quality of Campanula bononiensis L. (Campanulaceae, a protected species in Poland. Observations and measurements were made during the years 2007–2009 in natural phytocoenoses from the Festuco-Brometea class situated within the Lublin area, SE Poland. A considerable decrease (approx. 87% in population density was observed. Significant variations both in the amount of pollen (18.5%–34.8% of pollen in the total anther dry weight, i.e. 0.5–1.5 mg per 10 anthers and in pollen viability (38.8–97.0% were noted. Both a low amount of pollen and low pollen viability may reduce the reproductive success of individuals. The most frequent visiting insects were bees (Apoidea, including solitary bees 45.7%, honeybees 20.4%, and bumblebees 11.4%. Dipterans, coleopterans (weevils, lepidopterans and ants were also recorded, implying a strong impact of C. bononiensis on insect biodiversity within grasslands.

  9. Reef fishes in biodiversity hotspots are at greatest risk from loss of coral species.

    Science.gov (United States)

    Holbrook, Sally J; Schmitt, Russell J; Messmer, Vanessa; Brooks, Andrew J; Srinivasan, Maya; Munday, Philip L; Jones, Geoffrey P

    2015-01-01

    Coral reef ecosystems are under a variety of threats from global change and anthropogenic disturbances that are reducing the number and type of coral species on reefs. Coral reefs support upwards of one third of all marine species of fish, so the loss of coral habitat may have substantial consequences to local fish diversity. We posit that the effects of habitat degradation will be most severe in coral regions with highest biodiversity of fishes due to greater specialization by fishes for particular coral habitats. Our novel approach to this important but untested hypothesis was to conduct the same field experiment at three geographic locations across the Indo-Pacific biodiversity gradient (Papua New Guinea; Great Barrier Reef, Australia; French Polynesia). Specifically, we experimentally explored whether the response of local fish communities to identical changes in diversity of habitat-providing corals was independent of the size of the regional species pool of fishes. We found that the proportional reduction (sensitivity) in fish biodiversity to loss of coral diversity was greater for regions with larger background species pools, reflecting variation in the degree of habitat specialization of fishes across the Indo-Pacific diversity gradient. This result implies that habitat-associated fish in diversity hotspots are at greater risk of local extinction to a given loss of habitat diversity compared to regions with lower species richness. This mechanism, related to the positive relationship between habitat specialization and regional biodiversity, and the elevated extinction risk this poses for biodiversity hotspots, may apply to species in other types of ecosystems.

  10. Reef fishes in biodiversity hotspots are at greatest risk from loss of coral species.

    Directory of Open Access Journals (Sweden)

    Sally J Holbrook

    Full Text Available Coral reef ecosystems are under a variety of threats from global change and anthropogenic disturbances that are reducing the number and type of coral species on reefs. Coral reefs support upwards of one third of all marine species of fish, so the loss of coral habitat may have substantial consequences to local fish diversity. We posit that the effects of habitat degradation will be most severe in coral regions with highest biodiversity of fishes due to greater specialization by fishes for particular coral habitats. Our novel approach to this important but untested hypothesis was to conduct the same field experiment at three geographic locations across the Indo-Pacific biodiversity gradient (Papua New Guinea; Great Barrier Reef, Australia; French Polynesia. Specifically, we experimentally explored whether the response of local fish communities to identical changes in diversity of habitat-providing corals was independent of the size of the regional species pool of fishes. We found that the proportional reduction (sensitivity in fish biodiversity to loss of coral diversity was greater for regions with larger background species pools, reflecting variation in the degree of habitat specialization of fishes across the Indo-Pacific diversity gradient. This result implies that habitat-associated fish in diversity hotspots are at greater risk of local extinction to a given loss of habitat diversity compared to regions with lower species richness. This mechanism, related to the positive relationship between habitat specialization and regional biodiversity, and the elevated extinction risk this poses for biodiversity hotspots, may apply to species in other types of ecosystems.

  11. Shearwater foraging in the Southern Ocean: the roles of prey availability and winds.

    Directory of Open Access Journals (Sweden)

    Ben Raymond

    Full Text Available BACKGROUND: Sooty (Puffinus griseus and short-tailed (P. tenuirostris shearwaters are abundant seabirds that range widely across global oceans. Understanding the foraging ecology of these species in the Southern Ocean is important for monitoring and ecosystem conservation and management. METHODOLOGY/PRINCIPAL FINDINGS: Tracking data from sooty and short-tailed shearwaters from three regions of New Zealand and Australia were combined with at-sea observations of shearwaters in the Southern Ocean, physical oceanography, near-surface copepod distributions, pelagic trawl data, and synoptic near-surface winds. Shearwaters from all three regions foraged in the Polar Front zone, and showed particular overlap in the region around 140 degrees E. Short-tailed shearwaters from South Australia also foraged in Antarctic waters south of the Polar Front. The spatial distribution of shearwater foraging effort in the Polar Front zone was matched by patterns in large-scale upwelling, primary production, and abundances of copepods and myctophid fish. Oceanic winds were found to be broad determinants of foraging distribution, and of the flight paths taken by the birds on long foraging trips to Antarctic waters. CONCLUSIONS/SIGNIFICANCE: The shearwaters displayed foraging site fidelity and overlap of foraging habitat between species and populations that may enhance their utility as indicators of Southern Ocean ecosystems. The results highlight the importance of upwellings due to interactions of the Antarctic Circumpolar Current with large-scale bottom topography, and the corresponding localised increases in the productivity of the Polar Front ecosystem.

  12. Interactions between shoal size and conformity in guppy social foraging

    OpenAIRE

    Day, R.L.; MacDonald, T; Brown, C.; Laland, K.N.; Reader, S.M.

    2001-01-01

    Previous experimental studies have established that shoaling fish forage more effectively in large than small groups. We investigated how shoal size affects the foraging efficiency of laboratory populations of the guppy, Poecilia reticulata, exposed to different foraging tasks. Experiment 1 confirmed the prediction that in open water the first fish and focal fish of larger shoals locate food faster than in smaller shoals. However, a second experiment, in which shoals of fish were required to ...

  13. Observations of the distributions of five fish species in a small Appalachian stream

    Science.gov (United States)

    Larson, Gary L.; Hoffman, Robert L.; Moore, S.E.

    2002-01-01

    The notion has been growing that resident stream fishes exhibit a greater capacity for movement than was previously thought. In this study, we recorded the distributions of four resident fish species (longnose dace Rhinichthys cataractae, blacknose dace R. atratulus, mottled sculpin Cottus bairdi, and rainbow trout Oncorhynchus mykiss) and one nonresident species (central stoneroller Campostoma anomalum) in Rock Creek, a small tributary of Cosby Creek in Great Smoky Mountains National Park, over the period 1979a??1995. During this study, 1,998 individuals of resident species were collected from stream sections considered to be within a common area of distribution for each species. Forty-five individuals of resident and nonresident species were captured upstream of these areas, and eight of these fish were considered to be larger than individuals considered typical for each species. Small mammal dispersal theory concepts were used to classify and describe fish movements outside of common areas of distribution. These movements were identified as important in maintaining population connectivity within stream drainages, contributing to reducing the potential for local extinctions of populations and to the recolonization of unoccupied habitats. This study highlights the need for continued study of fish movements in stream drainages and for development of appropriate resource management strategies based partly on the spatial dynamics of fish populations and communities.

  14. Study on Fishery Ecological Environment and Fish Species Diversity in Yantan Water Area

    Institute of Scientific and Technical Information of China (English)

    Yaoquan; HAN; Anyou; HE; Li; HUANG; Jun; SHI; Dapeng; WANG; Weijun; WU

    2015-01-01

    Through analysis on water quality,planktonic organism,fish resources,and fish species diversity in Yantan water area,this paper evaluated current situation of quality of fishery ecological environment in Yantan water area. The survey recorded all 52365 fishes and 1410. 2kg catches obtained by fishermen in half a year,and more than 98% catches are small fishes. The Shannon-Weiner diversity index of Yantan water area is 0. 162,Wilhm improvement index is 1. 814,DG- Findex is 0. 083,and the index of fish species diversity is far lower than other water areas. The average quantity per unit of phytoplankton is 1. 0134 million ind. / L,and the average quantity per unit of organisms is 1. 1151 mg / L. The average quantity per unit of zooplankton is 459. 6 ind. / L,and the average quantity per unit of organisms is 0. 6422 mg / L. Evaluation results indicate that water quality and planktonic organism in Yantan water area are basically normal,but fish resources are increasingly exhausted,fish resource composition is not reasonable,and fish species diversity is extremely low. From the perspective of biomanipulation,it is required to restore fishery ecological environment of reservoir area through restoring normal composition of aquatic organisms.

  15. Nutrient composition of important fish species in Bangladesh and potential contribution to recommended nutrient intakes

    DEFF Research Database (Denmark)

    Bogard, Jessica R.; Thilsted, Shakuntala H.; Marks, Geoffrey C.;

    2015-01-01

    Fish, in Bangladesh where malnutrition remains a significant development challenge, is an irreplaceable animal-source food in the diet of millions. However, existing data on the nutrient composition of fish do not reflect the large diversity available and have focused on only a few select nutrients....... The purpose of this study was to fill the gaps in existing data on the nutrient profiles of common fish in Bangladesh by analysing the proximate, vitamin, mineral and fatty acid composition of 55 fish, shrimp and prawn species from inland capture, aquaculture and marine capture fisheries. When comparing......, and all typically consumed whole with head and bones, could potentially contribute ≥25% of RNIs for three or more of these nutrients, simultaneously, from a standard portion. This illustrates the diversity in nutrient content of fish species and in particular the rich nutrient composition of small...

  16. The effect of seasonality on fish species composition and abundance in Rungan river floodplain, Palangkaraya, Central Kalimantan

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    BAMBANG SULISTIYARTO

    2007-10-01

    Full Text Available Tropical floodplain rivers are home to the largest fraction of freshwater fish diversity and as such should be a focal point of fish conservation efforts. The aim of this study was to inventory of the fish fauna and analyzing the effect of seasonality on fish species composition and abundance in the Rungan river floodplain at Palangkaraya Municipality. The results of this study provide background data for conserving fish resources. Fishes were sampled at monthly intervals between May 2005 and April 2006 with gillnets of standardized dimensions with several mesh sizes. These were carried out at three stations with different habitat type, includes forested swamp, opened swamp, and river. A total of 4278 fishes were collected consisting of 50 species and 19 families. Seasonality effects on fish species composition and abundance in forested swamp and river. Fish species composition and abundance in opened swamp tend not to drive by seasonality.

  17. Using a Popular Pet Fish Species to Study Territorial Behaviour

    Science.gov (United States)

    Abante, Maria E.

    2005-01-01

    The colourful, vigorous territorial display behaviour of the Siamese fighting fish, "Betta splendens", has great appeal for both pet enthusiasts and animal behaviourists. Their beauty, longevity, easy maintenance and rearing make them a popular pet and an ideal science laboratory specimen. This investigation utilises "B. splendens" to test for the…

  18. Discriminant classification of different fish-species backscattering

    Science.gov (United States)

    Zhang, Qiao; Xu, Feng; Liu, Yin; Zhang, Chun

    2012-11-01

    The complex structure of fish and multispecies composition complicate the analysis of acoustic data. Consequently, it is difficult to obtain a highly accurate rate of classification by using current approaches. This paper introduces two discriminating methods: the adaptive segmentation temporal centroid method and the wavelet packet multi-scale information entropy method. To verify and compare these two methods, an ex situ experiment has been performed with three kinds of fish: Crucian carp (Carassius auratus), Yellow-headed catfish (Pelteobagrus fulvidraco) and Bluntnose black bream (Megalobrama amblycephale). The backscattering signals of these fishes are obtained. Then the temporal centroid in the divided sub-segmentation of the backscattering envelope is calculated, and the multi-scale information entropy of the wavelet packet decomposition in different frequency bands is extracted. Finally, three kinds of fish are successfully classified by using a BP neural network. The result shows that the adaptive segmentation temporal centroid method is 4% more accurate than the wavelet packet multi-scale information entropy method.

  19. DNA barcoding for species assignment: the case of Mediterranean marine fishes.

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    Monica Landi

    Full Text Available BACKGROUND: DNA barcoding enhances the prospects for species-level identifications globally using a standardized and authenticated DNA-based approach. Reference libraries comprising validated DNA barcodes (COI constitute robust datasets for testing query sequences, providing considerable utility to identify marine fish and other organisms. Here we test the feasibility of using DNA barcoding to assign species to tissue samples from fish collected in the central Mediterranean Sea, a major contributor to the European marine ichthyofaunal diversity. METHODOLOGY/PRINCIPAL FINDINGS: A dataset of 1278 DNA barcodes, representing 218 marine fish species, was used to test the utility of DNA barcodes to assign species from query sequences. We tested query sequences against 1 a reference library of ranked DNA barcodes from the neighbouring North East Atlantic, and 2 the public databases BOLD and GenBank. In the first case, a reference library comprising DNA barcodes with reliability grades for 146 fish species was used as diagnostic dataset to screen 486 query DNA sequences from fish specimens collected in the central basin of the Mediterranean Sea. Of all query sequences suitable for comparisons 98% were unambiguously confirmed through complete match with reference DNA barcodes. In the second case, it was possible to assign species to 83% (BOLD-IDS and 72% (GenBank of the sequences from the Mediterranean. Relatively high intraspecific genetic distances were found in 7 species (2.2%-18.74%, most of them of high commercial relevance, suggesting possible cryptic species. CONCLUSION/SIGNIFICANCE: We emphasize the discriminatory power of COI barcodes and their application to cases requiring species level resolution starting from query sequences. Results highlight the value of public reference libraries of reliability grade-annotated DNA barcodes, to identify species from different geographical origins. The ability to assign species with high precision from DNA

  20. Food limitation of sea lion pups and the decline of forage off central and southern California.

    Science.gov (United States)

    McClatchie, Sam; Field, John; Thompson, Andrew R; Gerrodette, Tim; Lowry, Mark; Fiedler, Paul C; Watson, William; Nieto, Karen M; Vetter, Russell D

    2016-03-01

    California sea lions increased from approximately 50 000 to 340 000 animals in the last 40 years, and their pups are starving and stranding on beaches in southern California, raising questions about the adequacy of their food supply. We investigated whether the declining sea lion pup weight at San Miguel rookery was associated with changes in abundance and quality of sardine, anchovy, rockfish and market squid forage. In the last decade off central California, where breeding female sea lions from San Miguel rookery feed, sardine and anchovy greatly decreased in biomass, whereas market squid and rockfish abundance increased. Pup weights fell as forage food quality declined associated with changes in the relative abundances of forage species. A model explained 67% of the variance in pup weights using forage from central and southern California and 81% of the variance in pup weights using forage from the female sea lion foraging range. A shift from high to poor quality forage for breeding females results in food limitation of the pups, ultimately flooding animal rescue centres with starving sea lion pups. Our study is unusual in using a long-term, fishery-independent dataset to directly address an important consequence of forage decline on the productivity of a large marine predator. Whether forage declines are environmentally driven, are due to a combination of environmental drivers and fishing removals, or are due to density-dependent interactions between forage and sea lions is uncertain. However, declining forage abundance and quality was coherent over a large area (32.5-38° N) for a decade, suggesting that trends in forage are environmentally driven.

  1. Characterization of the gut microbiota of three commercially valuable warmwater fish species.

    Science.gov (United States)

    Larsen, A M; Mohammed, H H; Arias, C R

    2014-06-01

    Due to the strong influence of the gut microbiota on fish health, dominant bacterial species in the gut are strong candidates for probiotics. This study aimed to characterize the gut microbiota of channel catfish Ictalurus punctatus, largemouth bass Micropterus salmoides and bluegill Lepomis macrochirus to provide a baseline for future probiotic studies. The gut microbiota of five pooled individuals from each fish species was identified using 16S rRNA pyrosequencing. Microbiota differed significantly between fish species in terms of bacterial species evenness. However, all gut communities analysed were dominated by the phylum Fusobacteria, specifically the species Cetobacterium somerae. Relatively high abundances of the human pathogens Plesiomonas shigelloides and Fusobacterium mortiferum, as well as members of the genus Aeromonas, suggest these species are normal inhabitants of the gut. The overwhelming dominance of the genus Cetobacterium in all species warrants further investigation into its role in the fish gut microbiota. This study provides the first characterization of the gut microbiota of three economically significant fishes and establishes a baseline for future probiotic trials. © 2014 The Society for Applied Microbiology.

  2. [Inner- and inter-species differences of mercury concentration in common fishes from the Yellow Sea].

    Science.gov (United States)

    Zhu, Ai-Jia; Xu, Zhan-Zhou; Liu, Gui-Ze; Deng, Li-Jie; Fang, Hong-Da; Huang, Liang-Min

    2014-02-01

    Mercury concentration in marine fishes and its influencing factors are the key problems in the study of mercury biomagnification in marine ecosystems. In order to understand the inner- and inter-species differences of mercury concentration in fishes from the Yellow Sea, a total of 164 marine wild fishes covering nine different species were collected from the area from August to October, 2012. Mercury (total mercury) concentration in fish muscle tissue was measured by a direct mercury analyzer. Body length and wet weight of each sample were also determined. Moreover, feeding habit and trophic level of different species were examined. Hg concentrations (dry weight) in the muscle tissues of the 164 individuals ranged from 0.025 micro x g(-1) to 0.526 microg x g(-1), with an average of (0.124 +/- 0.096) microg x g(-1). By an inner-species analysis, log10 Hg concentration was significantly correlated to their body length and wet weight. Predator fishes with trophic level > 2.8 were more readily to be contaminated by Hg than the filter feeder with trophic level fishes from the Yellow Sea, while dietary preference, trophic level and increasing rate of weight are the main factors affecting the inter-species difference from the Yellow Sea.

  3. Primary versus secondary drivers of foraging activity in sandeel schools (Ammodytes tobianus)

    DEFF Research Database (Denmark)

    Deurs, Mikael van; Behrens, Jane; Warnar, Thomas

    2011-01-01

    to fishery biologists and has consequences for a wide range of predators ranging from birds and mammals to commercially important species. However, experimental studies that shed light on the primary drivers of foraging activity in fish are rare. In the present study, whole schools of sandeel (A. tobianus...

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

    Directory of Open Access Journals (Sweden)

    Gretchen J A Hansen

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

  5. Effect of processing conditions on trace elements in fish roe from six commercial new zealand fish species.

    Science.gov (United States)

    Bekhit, Alaa El-Din A; Morton, James D; Dawson, Chris O

    2008-06-25

    The concentrations of trace elements in fish roes and the effect of processing conditions (karasumi-like or karashi mentaiko) were investigated in six commercial fish species from New Zealand. The studied elements were As, Cd, Cr, Cu, Hg, Pb, and Zn, and the roes were from the following species: chinook salmon ( Oncorhynchus tshawytscha), hoki ( Macruronus novaezelandiae), southern blue whiting ( Micromesistius australis), hake ( Merluccius australis), blue warehou ( Seriolella brama), and barracouta ( Thyrsites atun). The concentrations of As, Cd, Cr, Hg, and Pb in the roes were lower than literature values for fish muscles. Only Zn in barracouta roe and Cu in salmon roe and their products were relatively higher than the generally accepted levels in fish muscles and could be of safety concern. Hence, the consumption of barracouta and salmon roes among certain parts of the population needs to be monitored and assessed. Dry salting (karasumi-like) processing increased ( P elements while salting fermentation (karashi mentaiko) processing tended to decrease the levels of trace elements. Fermentation may be a useful process to decrease the level of toxic trace elements.

  6. Species richness and patterns of invasion in plants, birds, and fishes in the United States

    Science.gov (United States)

    Stohlgren, Thomas J.; Barnett, David; Flather, Curtis; Fuller, Pamela L.; Peterjohn, Bruce G.; Kartesz, John; Master, Lawrence L.

    2006-01-01

    We quantified broad-scale patterns of species richness and species density (mean # species/km2) for native and non-indigenous plants, birds, and fishes in the continental USA and Hawaii. We hypothesized that the species density of native and non-indigenous taxa would generally decrease in northern latitudes and higher elevations following declines in potential evapotranspiration, mean temperature, and precipitation. County data on plants (n = 3004 counties) and birds (n=3074 counties), and drainage (6 HUC) data on fishes (n = 328 drainages) showed that the densities of native and non-indigenous species were strongly positively correlated for plant species (r = 0.86, P coast with high precipitation and productivity (vegetation carbon). We show that (1) native species richness can be moderately well predicted with abiotic factors; (2) human populations have tended to settle in areas rich in native species; and (3) the richness and density of non-indigenous plant, bird, and fish species can be accurately predicted from biotic and abiotic factors largely because they are positively correlated to native species densities. We conclude that while humans facilitate the initial establishment, invasions of non-indigenous species, the spread and subsequent distributions of non-indigenous species may be controlled largely by environmental factors.

  7. Linking fish species traits to environmental conditions in the Jakarta Bay-Pulau Seribu coral reef system.

    Science.gov (United States)

    Cleary, Daniel F R

    2017-09-15

    Coral reefs around the globe have been subjected to a wide range of stressors. In the present study, fish species were recorded across a pronounced in-to-offshore gradient in the Jakarta Bay-Pulau Seribu reef system. In addition to this, fish species traits were obtained from FishBase. RLQ analysis revealed a significant association between fish species traits and environmental variables. Fish species associated with perturbed, inshore waters were resilient to disturbance, had higher mortality rates, higher growth rates and mainly consumed animals. In contrast, fish species associated with less perturbed, mid- and offshore waters had greater life expectancy, higher age at maturity, greater life span, greater generation time and mainly fed on plants or plants and animals. Eutrophication, pollution and physical destruction of coral substrate in inshore waters has thus selected for a low biomass and depauperate fish community characterised by fast growing and short lived species. Copyright © 2017. Published by Elsevier Ltd.

  8. Distribution Species Composition And Size Of Flying Fish Exocoetidae In The Ceram Sea

    Directory of Open Access Journals (Sweden)

    Friesland Tuapetel

    2015-03-01

    Full Text Available Abstract Ceram Sea is new resources area of catching flying fish. The purpose of study is to determine the species composition size and distribution of flying fish caught by drifting baits. Flying fish data collection was conducted in June until October 2013 in three locations i.e Kaimana East Ceram and Fak-Fak. There are three flying fish species collected namely Hirundichthys oxycephalus Torani Cypselurus poecilopterus Banggulung and Chellopogon abeia yellow wing. The results was showed that in Fak-Fak and Kaimana there are two types of fly fishing that H. oxycephalus andC. poecilopterus whereas in East Ceram found three types including H. oxycephalus C. poecilopterus and C. abeia. The dominant type of flying fish in three locations is H. oxycephalus. Flying fish has a variety size range of body size from 195.6 to 243.6 mm in Kaimana East Ceram range from 206.3 to 284.3 mm while Fak-Fak range from 187.1 to 243.1 mm. The result is expected to be a reference literature as basic data for the management and sustainable utilization of flyling fish in Ceram sea.

  9. Marine fronts are important fishing areas for demersal species at the Argentine Sea (Southwest Atlantic Ocean)

    Science.gov (United States)

    Alemany, Daniela; Acha, Eduardo M.; Iribarne, Oscar O.

    2014-03-01

    The high primary and secondary production associated with frontal systems attract a diversity of organisms due to high prey availability; this is why a strong relationship between fronts and pelagic fisheries has been shown worldwide. In the Argentine Sea, demersal resources are the most important, both in economical and in ecological sense; so we hypothesize that fronts are also preferred fishing areas for demersal resources. We evaluated the relationship between spatial distribution of fishing effort and oceanographic fronts, analyzing three of the most important frontal systems located in the Argentine Sea: the shelf-break front, the southern Patagonia front and the mid-shelf front. Individual vessel satellite monitoring system data (VMS; grouped by fleet type: ice-trawlers, freezer-trawlers and jigging fleet) were studied and fishing events were identified. Fishing events per area were used as a proxy of fishing effort and its spatial distribution by fleet type was visualized and analyzed with Geographic Information Systems. Oceanographic fronts were defined using polygons based on satellite chlorophyll amplitude values, and the percentage of fishing events within each polygon was calculated. Results showed a positive association between fronts and fishing activities of the different fleets, which suggests the aggregation of target species in these zones. The coupling of the freezer-trawler and jigging fleets (that operate on lower trophic level species; Macruronus magellanicus and Illex argentinus respectively) with fronts was higher than the ice-trawler fleet, targeting species of higher trophic level (Merluccius hubbsi). Marine fronts represent important fishing areas, even for demersal resources, as the distribution of fishing fleets and fishing effort are positively associated with frontal zones.

  10. Polychlorinated biphenyls in sediments and fish species from the Murchison Bay of Lake Victoria, Uganda.

    Science.gov (United States)

    Ssebugere, Patrick; Sillanpää, Mika; Wang, Pu; Li, Yingming; Kiremire, Bernard T; Kasozi, Gabriel N; Zhu, Chaofei; Ren, Daiwei; Zhu, Nali; Zhang, Haidong; Shang, Hongtao; Zhang, Qinghua; Jiang, Guibin

    2014-06-01

    Polychlorinated biphenyls (PCBs) were determined in sediments and two fish species collected from the Murchison Bay in Lake Victoria, using high resolution gas chromatography coupled to a high resolution mass spectrometer. Total PCB concentrations (Σ18PCBs) varied widely with mean values ranging from 777 to 4325pg g(-1) dry weight (dw) for sediments and 80 to 779pg g(-1) wet weight (ww) for fish. The PCB levels in the sediments were significantly higher at the station closest to Nakivubo channel, presumably due to effluents discharged by the channel, which may contain domestically produced commercial PCB mixtures. For fish, the concentrations in Nile perch (Lates niloticus) were significantly greater than those in Nile tilapia (Oreochromis niloticus) at all study stations, possibly due to dietary differences among species. World Health Organization-toxic equivalents (WHO2005-TEQs) for the dioxin-like PCBs were 0.04-0.64pg g(-1) dw and 0.01-0.39pg g(-1) ww for sediments and fish, respectively. The non-ortho PCBs exhibited the highest contribution to the Σ12TEQs (>75%) compared to the mono-ortho PCBs in both fish species. The TEQs in the present study were lower than many reported worldwide in literature for fish and were within the permissible level recommended by the European Commission, implying that the fish did not pose health hazards related to PCBs to the consumers.

  11. Heavy metals toxicity and bioaccumulation patterns in the body organs of four fresh water fish species

    Directory of Open Access Journals (Sweden)

    Safina Kousar and Muhammad Javed

    2014-04-01

    Full Text Available Various environmental pollutants, including metals can cause toxicological effects on aquatic animals especially fish species. Laboratory experiments were conducted to determine acute toxicity and bioaccumulation patterns of arsenic (As, nickel (Ni and zinc (Zn in 150-day old fish species (Labeo rohita, Cirrhina mrigala, Catla catla and Ctenopharyngodon idella, separately, in glass aquaria under constant water temperature (30oC, total hardness (300 mg L-1 and pH (7.5. Catla catla showed significantly (PNi>As. Among exposed fish species, Cirrhina mrigala exhibited significantly higher ability to amass Ni (146.8±149.1 μg g-1 and Zn (243.0±190.5 μg g-1, followed by Ctenopharyngodon idella, Labeo rohita and Catla catla at 96-h LC50. Liver showed higher tendency to accumulate Ni, followed by gills and kidney with significant differences while kidney showed higher tendency to accumulate As, followed by liver. Fins and scales exhibited significantly (P<0.05 least tendency to accumulate all the three metals. Accumulation of metals in different fish species is the function of their membrane permeability, which is highly species specific. Due to this reason different fish species showed different amount of metal accumulated in their bodies. This study also reveals that the metals, being conservative in nature have higher ability of biomagnifications.

  12. Sampling effort and fish species richness in small terra firme forest streams of central Amazonia, Brazil

    Directory of Open Access Journals (Sweden)

    Maeda Batista dos Anjos

    Full Text Available Small streams are important components of the landscape in terra firme forests in central Amazonia and harbor a large number of fish species. Nevertheless, the lack of a common sampling protocol in studies of this ichthyofauna hinders comparisons among available results. This study evaluates how the length of stream reach sampled affects estimates of local fish species density in 1st, 2nd, and 3rd order streams, and proposes a mean minimum sampling length that best approximates the absolute number of species in a given stream segment. We sampled three streams in the Biological Dynamics of Forest Fragments Project's study sites, between May and August 2004. At each stream, one 1st order, one 2nd order, and one 3rd order segment was sampled. We sampled five 20-m reaches in each stream segment. Three to four people collected along each reach for 45 to 60 minutes. We used Jaccard's coefficient to estimate the similarity of species composition among stream reaches and segments. Estimates of species richness were obtained with Jackknife 1 and Bootstrap algorithms and species accumulation curves. We used simple linear regressions to look for relationships between species density and fish abundance and between species density and the volume of 100-m stream segments. Species density in 1st order stream reaches was slightly higher than in 2nd and 3rd order stream reaches, whereas fish abundance was apparently higher in 3rd order reaches. Similarity in fish species composition between 20-m reaches was low for all studied streams. Species density values in pooled 100-m stream segments represented 71.4% to 94.1% of the estimated values for these streams. Species density showed a direct relationship both with volume of the sampled stream segment and fish abundance. It seems plausible that larger streams contain a higher number of microhabitat types, which allow for the presence of more fish species per stream length. Based on the values of asymptotes and

  13. Role of self-caught fish in total fish consumption rates for recreational fishermen: Average consumption for some species exceeds allowable intake.

    Science.gov (United States)

    Burger, Joanna

    2013-01-01

    Studies of fish consumption focus on recreational or subsistence fishing, on awareness and adherence to advisories, consumption patterns, and contaminants in fish. Yet the general public obtains their fish from commercial sources. In this paper I examine fish consumption patterns of recreational fishermen in New Jersey to determine: 1) consumption rates for self-caught fish and for other fish, 2) meals consumed per year, 3) average meal size, and average daily intake of mercury, and 4) variations in these parameters for commonly-consumed fish, and different methods of computing intake. Over 300 people were interviewed at fishing sites and fishing clubs along the New Jersey shore. Consumption patterns of anglers varied by species of fish. From 2 to 90 % of the anglers ate the different fish species, and between 9 and 75 % gave fish away to family or friends. Self-caught fish made up 7 to 92 % of fish diets. On average, self-caught fish were eaten for only 2 to 6 months of the year, whereas other fish (commercial or restaurant) were eaten up to 10 months a year. Anglers consumed from 5 to 36 meals of different fish a year, which resulted in intake of mercury ranging from 0.01 to 0.22 ug/kg/day. Average intake of Mako shark, swordfish, and tuna (sushi, canned tuna, self-caught tuna) exceeded the U.S. Environmental Protection Agency's oral, chronic reference dose for mercury of 0.1 ug/kg/day. However, computing intake using consumption for the highest month results in average mercury intake exceeding the reference dose for striped bass and bluefish as well. These data, and the variability in consumption patterns, have implications for risk assessors, risk managers, and health professionals.

  14. Do low-mercury terrestrial resources subsidize low-mercury growth of stream fish? Differences between species along a productivity gradient.

    Directory of Open Access Journals (Sweden)

    Darren M Ward

    Full Text Available Low productivity in aquatic ecosystems is associated with reduced individual growth of fish and increased concentrations of methylmercury (MeHg in fish and their prey. However, many stream-dwelling fish species can use terrestrially-derived food resources, potentially subsidizing growth at low-productivity sites, and, because terrestrial resources have lower MeHg concentrations than aquatic resources, preventing an increase in diet-borne MeHg accumulation. We used a large-scale field study to evaluate relationships among terrestrial subsidy use, growth, and MeHg concentrations in two stream-dwelling fish species across an in-stream productivity gradient. We sampled young-of-the-year brook trout (Salvelinus fontinalis and Atlantic salmon (Salmo salar, potential competitors with similar foraging habits, from 20 study sites in streams in New Hampshire and Massachusetts that encompassed a wide range of aquatic prey biomass. Stable isotope analysis showed that brook trout used more terrestrial resources than Atlantic salmon. Over their first growing season, Atlantic salmon tended to grow larger than brook trout at sites with high aquatic prey biomass, but brook grew two-fold larger than Atlantic salmon at sites with low aquatic prey biomass. The MeHg concentrations of brook trout and Atlantic salmon were similar at sites with high aquatic prey biomass and the MeHg concentrations of both species increased at sites with low prey biomass and high MeHg in aquatic prey. However, brook trout had three-fold lower MeHg concentrations than Atlantic salmon at low-productivity, high-MeHg sites. These results suggest that differential use of terrestrial resource subsidies reversed the growth asymmetry between potential competitors across a productivity gradient and, for one species, moderated the effect of low in-stream productivity on MeHg accumulation.

  15. Regional warming chnages fish species richness in the eastern North Atlantic Ocean

    NARCIS (Netherlands)

    Hofstede, ter R.; Hiddink, J.G.; Rijnsdorp, A.D.

    2010-01-01

    Regional warming causes changes in local communities due to species extinctions and latitudinal range shifts. We show that the species richness of fish in 3 regional seas in the eastern North Atlantic Ocean has changed over time (1997 to 2008), and we relate this to higher water temperatures and the

  16. Longitudinal zonation of Pacific Northwest (USA) fish assemblages and the species-discharge relationship

    Science.gov (United States)

    Fish ecologists often use species-discharge relationships (SDRs) to understand how species richness varies with aquatic habitat availability, but few SDR studies have considered whether the reported SDRs are scale-dependent, or attributed the SDR to a specific causal mechanism. ...

  17. Genome analysis of 7 Kengyilia (Triticeae Poaceae) species with FISH and GISH

    Science.gov (United States)

    Genome composition of and genetic relationships among seven Kengyilia species were assessed using a technique of sequential FISH (fluorescence in situ hybridization) and GISH (genomic in situ hybridization). Five of these 7 species, K. kokonorica, K. rigidula, K. hirsula, K. grandiglumis, and K. th...

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

    Science.gov (United States)

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

    2014-07-01

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

  19. Application of instrumental neutron activation analysis for the analysis of six fish species

    Energy Technology Data Exchange (ETDEWEB)

    Moon, J. H.; Oh, M.; Kim, S. H.; Chung, Y. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    According to the meeting report of the Food and Agriculture Organization (FAO), annual food fish supply per capita has increased from an average of 9.9 kg in the 1960s to 18.4 kg in 2009, and fish consumption was lowest in Africans (9.1 kg per capita), while Asians consumed 20.7 kg per capita. From the viewpoint of food safety, fish accumulates environmental contaminants and an analysis of hazardous chemical species including toxic heavy metals is important for human health. The aims of this study were to determine the inorganic elemental content in six popular fish species of Korea by NAA and to aid in the evaluation of dietary intake levels in terms of toxic and essential elements. An INAA for the six fish species that are popular in Korea was performed, and sixteen elemental contents were determined. Based on these analytical data and survey data in 2010, intake levels for 3 toxic heavy metals by each fish species are evaluated for Koreans. These dietary intake values for heavy metals can be used for an assessment of human health risk.

  20. Fishes associated with spinner dolphins at Fernando de Noronha Archipelago, tropical Western Atlantic: an update and overview

    Directory of Open Access Journals (Sweden)

    Ivan Sazima

    Full Text Available An update is presented for fish species associated with spinner dolphins at Fernando de Noronha Archipelago, tropical Western Atlantic, providing a general view of their diversity. The associates are mostly reef-dwelling fishes that feed on the dolphin wastes. Twelve species are habitual or occasional plankton-eaters and two species are herbivores that occasionally forage on floating pieces of algae. One species is a strict carnivore, one species is a hitchhiker that forages on a variety of foods including parasites and dead tissue from the dolphins, and one species is a carnivore that joins the dolphin groups to forage on schools of small fishes or squids. We predict that the list of fish associated with spinner dolphins will expand mostly with addition of habitual or occasional plankton-eaters.

  1. Competition for shelter between four invasive gobiids and two native benthic fish species

    Directory of Open Access Journals (Sweden)

    N. VAN KESSEL, M. DORENBOSCH, M.R.M. DE BOER, R.S.E.W. LEUVEN,G. VAN DER VELDE

    2011-12-01

    Full Text Available Recent invasions by non-native gobiid fish species that are ongoing in the Western European rivers Rhine and Meuse, will lead to interactions with native benthic fish species. Since both non-native gobiids and native benthic species are bottom dwelling species with a preference for shelter during at least part of their life cycle, it is likely that competition for shelter will occur between these non-native and native species when shelter is a limiting factor. To investigate the importance of this mechanism for species replacements, various habitat choice experiments were conducted between two common native benthic fish species (Cottus perifretum and Barbatula barbatula and four invasive non-native gobiid species (Proterorhinus semilunaris, Neogobius melanostomus, N. kessleri and N. fluviatilis. The first series of single specimen experiments determined the habitat choice of each individual fish species. In a second series of competition experiments, shifts in habitat choice in comparison with the previously observed habitat choice, were determined when a native benthic fish species co-occurred with non-native gobiid species. Native C. perifretum displayed a significant shift in habitat choice in co-occurrence with the gobiids N. kessleri or P. semilunaris. C. perifretum was outcompeted and moved from the available shelter place to less preferred habitat types. During the competition experiments no change in habitat choice of B. barbatula was shown. Our study therefore suggests that competition for shelter is likely to occur in rivers invaded by N. kessleri and P. semilunaris at sites where shelter is limiting [Current Zoology 57 (6: 844–851, 2011].

  2. Competition for shelter between four invasive gobiids and two native benthic fish species

    Institute of Scientific and Technical Information of China (English)

    N. VAN KESSEL; M. DORENBOSCH; M.R.M. DE BOER; R.S.E.W. LEUVEN; G. VAN DER VELDE

    2011-01-01

    Recent invasions by non-native gobiid fish species that are ongoing in the Western European rivers Rhine and Meuse,will lead to interactions with native benthic fish species.Since both non-native gobiids and native benthic species are bottom dwelling species with a preference for shelter during at least part of their life cycle,it is likely that competition for shelter will occur between these non-native and native species when shelter is a limiting factor.To investigate the importance of this mechanism for species replacements,various habitat choice experiments were conducted between two common native benthic fish species ( Cottus perifretum and Barbatula barbatula) and four invasive non-native gobiid species ( Proterorhinus semilunaris,Neogobius melanostomus,N.kessleri and N.fluviatilis).The first series of single specimen experiments determined the habitat choice of each individual fish species.In a second series of competition experiments,shifts in habitat choice in comparison with the previously observed habitat choice,were determined when a native benthic fish species co-occurred with non-native gobiid species.Native C.perifretum displayed a significant shift in habitat choice in co-occurrence with the gobiids N.kessleri or P.semilunaris.C.perifretum was outcompeted and moved from the available shelter place to less preferred habitat types.During the competition experiments no change in habitat choice of B.barbatula was shown.Our study therefore suggests that competition for shelter is likely to occur in rivers invaded by N.kessleri and P.semilunaris at sites where shelter is limiting [Current Zoology 57 (6):844-851,2011].

  3. Fish farming of native species in Colombia: current situation and perspectives

    DEFF Research Database (Denmark)

    Cruz-Casallas, P. E.; Medina-Robles, V. M.; Velasco-Santamaria, Y. M.

    2011-01-01

    . The Colombian pisciculture is based on red Tilapia Oreochromis sp. (Linnaeus), Rainbow trout Oncorhynchus mykiss (Walbaum) and cachama blanca Piaractus brachypomus (Cuvier), which currently represent around 96% of the total national production. The remaining 4% comes from other farmed species such as bocachico......, food conversion and disease resistance. The limited offer of Colombian fish farmed species determines its currently low competitiveness and restricted impact on the international markets; thus making necessary to explore the potential of new fish species in order to introduce them to the pisciculture...

  4. Comparative study of infection with Tetrahymena of different ornamental fish species

    DEFF Research Database (Denmark)

    Sharon, G.; Leibowitz, M. Pimenta; Chettri, Jiwan Kumar;

    2014-01-01

    Tetrahymena is a ciliated protozoan that can infect a wide range of fish species, although it is most commonly reported in guppies (Poecilia reticulata). The aim of this study was to compare the susceptibility to infection with Tetrahymena of five different ornamental fish species from two...... different super orders. The species examined were platy (Xiphophorus), molly (Poecilia sphenops) and angelfish (Pterophyllum scalare) of the Acanthopterygii super order (which also includes guppies) and goldfish (Carassius auratus auratus) and koi carp (Cyprinus carpio) of the Ostariophysi super order...

  5. Competition in three Cyprinodont fish species in the Netherlands Antilles

    NARCIS (Netherlands)

    Kristensen, Ingvar

    1970-01-01

    Cyprinodon dearborni, Poecilia sphenops and Rivulus marmoratus seem to fill almost the same niche. In most of the landlocked bays, lagoons or pools the three species were not found together. In only two landlocked locations two of the species were found together. In the locations with an open connec

  6. Competition in three Cyprinodont fish species in the Netherlands Antilles

    NARCIS (Netherlands)

    Kristensen, Ingvar

    1970-01-01

    Cyprinodon dearborni, Poecilia sphenops and Rivulus marmoratus seem to fill almost the same niche. In most of the landlocked bays, lagoons or pools the three species were not found together. In only two landlocked locations two of the species were found together. In the locations with an open connec

  7. Content of essential polyunsaturated fatty acids in three canned fish species.

    Science.gov (United States)

    Gladyshev, Michail I; Sushchik, Nadezhda N; Makhutova, Olesia N; Kalachova, Galina S

    2009-05-01

    Three canned fish species--Pacific saury (Cololabis saira), Pacific herring (Clupea harengus) and Baltic sprat (Sprattus sprattus)--most common and popular in Russia, were analyzed for fatty acids. Special attention was paid to long-chain essential polyunsaturated fatty acids: eicosapentaenoic acid (20:5omega3) and docosahexaenoic acid (22:6omega3). Sums of eicosapentaenoic acid and docosahexaenoic acid in saury, herring and sprat were, on average, 2.42, 1.80 and 1.43 g/100 g product, respectively. Contents of these essential acids in all the canned fish species were found to be very high compared with many other fish reported in the available literature. All the canned fish appeared to be highly valuable products for human nutrition concerning the content of eicosapentaenoic and docosahexaenoic acids.

  8. Comparison of the Condition Factor of Five Fish Species of the Araguaia River Basin, Central Brazil

    Directory of Open Access Journals (Sweden)

    Bruno Bastos Gonçalves

    2016-06-01

    Full Text Available This study aims to assess the condition factor (K of five fish species (Serrasalmus rhombeus, Psectrogaster amazonica, Loricaria cataphracta, Panaque nigrolineatus and Squaliforma emarginata. Samplings were conducted during the low-water period of 2007 and 2008 using gillnets and minnow traps. All equipments were placed along a stretch of 1000 m at 5 pm and retrieved at 7 am. Collected fish were taxonomically identified, weighed (g and measured (standard length; mm. The fish fitness was assessed by the condition factor (K=W/L³ and compared among groups of tributaries by a Kruskal-Wallis test. From the five species considered, two (S. emarginata and P. amazonica displayed significant differences of the condition factor among the groups of tributaries. The highest values of K correspond to fish located in the headwaters, while lowest values are observed in tributaries located in the floodplain.

  9. Isolation of Birnavirus serogroup B in wild and aquacultured fish species

    DEFF Research Database (Denmark)

    Skall, Helle Frank; Mellergaard, Stig; Olesen, Niels Jørgen

    2000-01-01

    and the Kattegat. Surveillance of aquacultured fish, mainly rainbow trout (Oncorhynchus mykiss), for VHS, IHN and IPN, in Denmark during the previous 30 years, have resulted in Birnavirus serogroup B isolations twice. These isolations were from healthy rainbow trout. Samples sent to the Danish Veterinary......During cruises with Danish research vessels more than 17,000 wild marine fish belonging to 41 different species were sampled and examined virologically. Birnavirus serogroup B was isolated from 7 marine fish species: plaice (Pleuronectes platessa), dab (Limanda limanda), flounder (Platichthys...... Laboratory for virological examination and characterisation have revealed the presence of Birnavirus serogroup B in haddock (ML Melanogrammus aeglefinus), plaice and dab from wild marine fish caught by Irish fishermen and from Icelandic farmed halibut (Hippoglossus hippoglossus)....

  10. [Fish species richness evaluation in Mexican coastal lagoons: a case study in the Gulf of Mexico].

    Science.gov (United States)

    Pérez-Hernández, M A; Torres-Orozco, R E

    2000-01-01

    We analyze the origin of knowledge about fish species richness in the Tuxpan-Tampamachoco estuarine system, in Veracuz, México. A complete inventory of the fish species known to date for this system (N = 179) was elaborated from published lists and from sampling seagrass meadows of Tampamachoco Lagoon, which yielded 14 previously unknown species. When compared, the different lists showed a low similarity that may reflect differences in sampling methods and collecting strategies. Current data suggest that fish species richness in Mexican coastal lagoons (Gulf of Mexico) is not related with lagoon surface area, as has been suggested, but with the number of inventories available for each lagoon, being these a reflection of the sampling effort. A sampling design for the assessment of fish species richness in estuarine systems should consider: a) using the highest possible variety of sampling fishing gears, b) collecting in all microhabitat types and c) the preference of bimonthly or quarterly samplings for two or more years over monthly samplings in a single year.

  11. 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.

  12. Accumulation of trace elements in sediment and fish species of Paira River, Bangladesh

    Directory of Open Access Journals (Sweden)

    Md. Saiful Islam

    2017-03-01

    Full Text Available Sediments and tissues of eleven fish species (Channa punctata, Cyprinus carpio, Heteropneustes fossilis, Colisa fasciata, Channa striata, Notopterus notopterus, Tenualosa ilisha and Corica soborna were analyzed for (chromium (Cr, nickel (Ni, copper (Cu, arsenic (As, cadmium (Cd and lead (Pb. The abundance of trace elements in sediments were Cr > Ni > Cu > Pb > As > Cd and in fish species were Cu > Ni > Cr > Pb > As > Cd. The range of mean element concentration in fish species were Cr (0.44–0.97, Ni (0.45–1.1, Cu (0.91–1.5, As (0.18–0.37, Cd (0.016–0.20 and Pb (0.47–0.92 mg/kg wet weight (ww. The concentrations of Ni, Cd and Pb in some fish species exceeded the international permissible standards suggesting that these species are not safe for human consumption. The biota-sediment accumulation factor for the studied elements in C. soborna and T. ilisha were slightly higher than the other species indicated that these species can be used as a potential bio-indicator for the contamination study of trace elements.

  13. Identification of Cryptosporidium Species in Fish from Lake Geneva (Lac Leman in France.

    Directory of Open Access Journals (Sweden)

    Gabriela Certad

    Full Text Available Cryptosporidium, a protozoan parasite that can cause severe diarrhea in a wide range of vertebrates including humans, is increasingly recognized as a parasite of a diverse range of wildlife species. However, little data are available regarding the identification of Cryptosporidium species and genotypes in wild aquatic environments, and more particularly in edible freshwater fish. To evaluate the prevalence of Cryptosporidiumspp. in fish from Lake Geneva (Lac Léman in France, 41 entire fish and 100 fillets (cuts of fish flesh were collected from fishery suppliers around the lake. Nested PCR using degenerate primers followed by sequence analysis was used. Five fish species were identified as potential hosts of Cryptosporidium: Salvelinus alpinus, Esox lucius, Coregonus lavaretus, Perca fluviatilis, and Rutilus rutilus. The presence of Cryptosporidium spp. was found in 15 out of 41 fish (37%, distributed as follows: 13 (87% C. parvum, 1 (7% C. molnari, and 1 (7% mixed infection (C. parvum and C. molnari. C. molnari was identified in the stomach, while C. parvum was found in the stomach and intestine. C. molnari was also detected in 1 out of 100 analyzed fillets. In order to identify Cryptosporidium subtypes, sequencing of the highly polymorphic 60-kDa glycoprotein (gp60 was performed. Among the C. parvum positive samples, three gp60 subtypes were identified: IIaA15G2R1, IIaA16G2R1, and IIaA17G2R1. Histological examination confirmed the presence of potential developmental stages of C. parvum within digestive epithelial cells. These observations suggest that C. parvum is infecting fish, rather than being passively carried. Since C. parvum is a zoonotic species, fish potentially contaminated by the same subtypes found in terrestrial mammals would be an additional source of infection for humans and animals, and may also contribute to the contamination of the environment with this parasite. Moreover, the risk of human transmission is strengthened by

  14. Species richness and distribution of chondrichthyan fishes in the Arctic Ocean and adjacent seas

    DEFF Research Database (Denmark)

    Lynghammar, A.; Christiansen, J. S.; Mecklenburg, C. W.

    2013-01-01

    The sea ice cover decreases and human activity increases in Arctic waters. Fisheries and bycatch issues, shipping and petroleum exploitation (pollution issues) make it imperative to establish biological baselines for the marine fishes inhabiting the Arctic Ocean and adjacent seas (AOAS). Species...... richness, zoogeographic affiliations and Red List statuses among chondrichthyan fishes (Chondrichthyes) were examined across 16 AOAS regions as a first step towards credible conservation actions. Published literature and museum vouchers were consulted for presence/absence data. Although many regions...

  15. Identification of Cryptosporidium Species in Fish from Lake Geneva (Lac Léman) in France

    Science.gov (United States)

    Certad, Gabriela; Dupouy-Camet, Jean; Gantois, Nausicaa; Hammouma-Ghelboun, Ourida; Pottier, Muriel; Guyot, Karine; Benamrouz, Sadia; Osman, Marwan; Delaire, Baptiste; Creusy, Colette; Viscogliosi, Eric; Aliouat-Denis, Cecile Marie; Follet, Jérôme

    2015-01-01

    Cryptosporidium, a protozoan parasite that can cause severe diarrhea in a wide range of vertebrates including humans, is increasingly recognized as a parasite of a diverse range of wildlife species. However, little data are available regarding the identification of Cryptosporidium species and genotypes in wild aquatic environments, and more particularly in edible freshwater fish. To evaluate the prevalence of Cryptosporidiumspp. in fish from Lake Geneva (Lac Léman) in France, 41 entire fish and 100 fillets (cuts of fish flesh) were collected from fishery suppliers around the lake. Nested PCR using degenerate primers followed by sequence analysis was used. Five fish species were identified as potential hosts of Cryptosporidium: Salvelinus alpinus, Esox lucius, Coregonus lavaretus, Perca fluviatilis, and Rutilus rutilus. The presence of Cryptosporidium spp. was found in 15 out of 41 fish (37%), distributed as follows: 13 (87%) C. parvum, 1 (7%) C. molnari, and 1 (7%) mixed infection (C. parvum and C. molnari). C. molnari was identified in the stomach, while C. parvum was found in the stomach and intestine. C. molnari was also detected in 1 out of 100 analyzed fillets. In order to identify Cryptosporidium subtypes, sequencing of the highly polymorphic 60-kDa glycoprotein (gp60) was performed. Among the C. parvum positive samples, three gp60 subtypes were identified: IIaA15G2R1, IIaA16G2R1, and IIaA17G2R1. Histological examination confirmed the presence of potential developmental stages of C. parvum within digestive epithelial cells. These observations suggest that C. parvum is infecting fish, rather than being passively carried. Since C. parvum is a zoonotic species, fish potentially contaminated by the same subtypes found in terrestrial mammals would be an additional source of infection for humans and animals, and may also contribute to the contamination of the environment with this parasite. Moreover, the risk of human transmission is strengthened by the

  16. Culverts in paved roads as suitable passages for Neotropical fish species

    OpenAIRE

    Sergio Makrakis; Theodore Castro-Santos; Maristela Cavicchioli Makrakis; Ricardo Luiz Wagner; Maurício Spagnolo Adames

    2012-01-01

    Improperly installed or poorly maintained culverts can pose a serious threat to fish by disrupting their habitat and endangering spawning success. Road culverts that are not designed for fish passage frequently can become obstacles. This can be especially problematic for migratory species, but can lead to fragmentation of resident populations as well. This study evaluated 40 culverts of 29 sites within a 25-km radius from Toledo city, Paraná State, southern Brazil, with respect to their likel...

  17. Distribution of Aeromonas Species in the Intestinal Tracts of River Fish

    OpenAIRE

    1995-01-01

    Aeromonas isolates were obtained from fish intestines, water, and sediments from an urban river and identified by the DNA-DNA microplate hybridization method. The isolates were Aeromonas veronii (22%), Aeromonas caviae (18%), Aeromonas hydrophila (13%), Aeromonas sobria (8%), Aeromonas jandaei (7%), and other Aeromonas spp. (33%). Aeromonas species occurred at high densities with high incidences, regardless of season. The results strongly suggest that aeromonads are indigenous in fish intesti...

  18. Identification of Cryptosporidium Species in Fish from Lake Geneva (Lac Léman) in France.

    Science.gov (United States)

    Certad, Gabriela; Dupouy-Camet, Jean; Gantois, Nausicaa; Hammouma-Ghelboun, Ourida; Pottier, Muriel; Guyot, Karine; Benamrouz, Sadia; Osman, Marwan; Delaire, Baptiste; Creusy, Colette; Viscogliosi, Eric; Dei-Cas, Eduardo; Aliouat-Denis, Cecile Marie; Follet, Jérôme

    2015-01-01

    Cryptosporidium, a protozoan parasite that can cause severe diarrhea in a wide range of vertebrates including humans, is increasingly recognized as a parasite of a diverse range of wildlife species. However, little data are available regarding the identification of Cryptosporidium species and genotypes in wild aquatic environments, and more particularly in edible freshwater fish. To evaluate the prevalence of Cryptosporidiumspp. in fish from Lake Geneva (Lac Léman) in France, 41 entire fish and 100 fillets (cuts of fish flesh) were collected from fishery suppliers around the lake. Nested PCR using degenerate primers followed by sequence analysis was used. Five fish species were identified as potential hosts of Cryptosporidium: Salvelinus alpinus, Esox lucius, Coregonus lavaretus, Perca fluviatilis, and Rutilus rutilus. The presence of Cryptosporidium spp. was found in 15 out of 41 fish (37%), distributed as follows: 13 (87%) C. parvum, 1 (7%) C. molnari, and 1 (7%) mixed infection (C. parvum and C. molnari). C. molnari was identified in the stomach, while C. parvum was found in the stomach and intestine. C. molnari was also detected in 1 out of 100 analyzed fillets. In order to identify Cryptosporidium subtypes, sequencing of the highly polymorphic 60-kDa glycoprotein (gp60) was performed. Among the C. parvum positive samples, three gp60 subtypes were identified: IIaA15G2R1, IIaA16G2R1, and IIaA17G2R1. Histological examination confirmed the presence of potential developmental stages of C. parvum within digestive epithelial cells. These observations suggest that C. parvum is infecting fish, rather than being passively carried. Since C. parvum is a zoonotic species, fish potentially contaminated by the same subtypes found in terrestrial mammals would be an additional source of infection for humans and animals, and may also contribute to the contamination of the environment with this parasite. Moreover, the risk of human transmission is strengthened by the

  19. Can pelagic forage fish and spawning cisco (Coregonus artedi) biomass in the western arm of Lake Superior be assessed with a single summer survey?

    Science.gov (United States)

    Yule, D.L.; Stockwell, J.D.; Schreiner, D.R.; Evrard, L.M.; Balge, M.; Hrabik, T.R.

    2009-01-01

    Management efforts to rehabilitate lake trout Salvelinus namaycush in Lake Superior have been successful and the recent increase in their numbers has led to interest in measuring biomass of pelagic prey fish species important to these predators. Lake Superior cisco Coregonus artedi currently support roe fisheries and determining the sustainability of these fisheries is an important management issue. We conducted acoustic and midwater trawl surveys of the western arm of Lake Superior during three periods: summer (July-August), October, and November 2006 to determine if a single survey can be timed to estimate biomass of both prey fish and spawning cisco. We evaluated our methods by comparing observed trawl catches of small (cisco increased substantially in November, while small bloater Coregonus hoyi biomass was lower. We compared our summer 2006 estimates of total fish biomass to the results of a summer survey in 1997 and obtained similar results. We conclude that the temporal window for obtaining biomass estimates of pelagic prey species in the western arm of Lake Superior is wide (July through October), but estimating spawning cisco abundance is best done with a November survey.

  20. Salinity and temperature tolerance of an emergent alien species, the Amazon fish Astronotus ocellatus

    Science.gov (United States)

    Gutierrel, Silvia M M; Schofield, Pam; Prodocimo, Viviane

    2016-01-01

    Astronotus ocellatus (oscar), is native to the Amazon basin and, although it has been introduced to many countries, little is known regarding its tolerances for salinity and temperature. In this report, we provide data on the tolerance of A. ocellatus to abrupt and gradual changes in salinity, its high and low temperature tolerance, and information on how salinity, temperature, and fish size interact to affect survival. Fish were able to survive abrupt transfer to salinities as high as 16 ppt with no mortality. When salinity change was gradual (2 ppt/day), fish in the warm-temperature experiment (28°C) survived longer than fish in the cool-temperature experiment (18°C). Larger fish survived longer than smaller ones at the higher salinities when the temperature was warm, but when the temperature was cool fish size had little effect on survival. In the temperature-tolerance experiments, fish survived from 9 to 41°C for short periods of time. Overall, the species showed a wide range of temperature and salinity tolerance. Thus, in spite of the tropical freshwater origin of this species, physiological stress is not likely to hinder its dispersal to brackish waters, especially when temperatures are warm.

  1. Hazardous impact of arsenic on tissues of same fish species collected from two ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Abdul Qadir, E-mail: aqshah07@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Kazi, Tasneem Gul, E-mail: tgkazi@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Arain, Mohammad Balal, E-mail: bilal_KU2004@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Baig, Jameel Ahmed, E-mail: jab_mughal@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Afridi, Hassan Imran, E-mail: hassanimranafridi@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Kandhro, Ghulam Abbas, E-mail: gakandhro@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Khan, Sumaira, E-mail: skhanzai@gmail.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Jamali, Mohammad Khan, E-mail: mkhanjamali@yahoo.com [Government degree college Usta Mohammad Balochistan Pakistan (Pakistan)

    2009-08-15

    The purpose of this paper is to develop a database of fish tissues and to evaluate concentration of arsenic (As) in five tissues of fish species collected from Manchar Lake Pakistan and to compare concentration of As in fish tissues of same fish species collected from the Indus River, Pakistan. A sensitive and precise, hydride generation atomic absorption spectrometry (HG AAS) method is presented for the determination of total Arsenic (As). Microwave acid-assisted digestion (MAD) procedure based on the mixture HNO{sub 3}/H{sub 2}O{sub 2} was evaluated. The method was successfully validated against CRM DORM-2 (dogfish muscle). Quantitative As recovery in CRM (DORM-2) was obtained and no statistical differences were found at 95% level by applying the t-test. The limit of detection (LOD) and limit of quantitation (LOQ), for As were established as 0.022 and 0.063 {mu}g g{sup -1}, respectively. The results of this study indicated that As concentration in fish tissues from the Indus River are generally lower than in tissues of fishes from Manchar Lake. Arsenic concentrations in fish tissues of Indus River are although above the respective human health-based concentrations.

  2. Chlamydial infections of fish: diverse pathogens and emerging causes of disease in aquaculture species.

    Science.gov (United States)

    Stride, M C; Polkinghorne, A; Nowak, B F

    2014-05-14

    Chlamydial infections of fish are emerging as an important cause of disease in new and established aquaculture industries. To date, epitheliocystis, a skin and gill disease associated with infection by these obligate intracellular pathogens, has been described in over 90 fish species, including hosts from marine and fresh water environments. Aided by advances in molecular detection and typing, recent years have seen an explosion in the description of these epitheliocystis-related chlamydial pathogens of fish, significantly broadening our knowledge of the genetic diversity of the order Chlamydiales. Remarkably, in most cases, it seems that each new piscine host studied has revealed the presence of a phylogenetically unique and novel chlamydial pathogen, providing researchers with a fascinating opportunity to understand the origin, evolution and adaptation of their traditional terrestrial chlamydial relatives. Despite the advances in this area, much still needs to be learnt about the epidemiology of chlamydial infections in fish if these pathogens are to be controlled in farmed environments. The lack of in vitro methods for culturing of chlamydial pathogens of fish is a major hindrance to this field. This review provides an update on our current knowledge of the taxonomy and diversity of chlamydial pathogens of fish, discusses the impact of these infections on the health, and highlights further areas of research required to understand the biology and epidemiology of this important emerging group of fish pathogens of aquaculture species.

  3. Effects of low-frequency naval sonar exposure on three species of fish.

    Science.gov (United States)

    Halvorsen, Michele B; Zeddies, David G; Chicoine, David; Popper, Arthur N

    2013-08-01

    To address growing concern over the impact of anthropogenic sound on fishes, a series of experiments was conducted that exposed several fish species to high-intensity low-frequency naval sonar. This study extends auditory findings by adding largemouth bass, yellow perch, and channel catfish. No effects on hearing were found in largemouth bass and yellow perch and only small effects in channel catfish (a fish with morphological adaptations for enhanced pressure reception). Together with prior findings, these results suggest limited impact on hearing from high-intensity sonar. Susceptibility may be due to genetic stock, developmental conditions, seasonal variation, and/or buoyancy during exposure.

  4. Paternal identity impacts embryonic development for two species of freshwater fish

    DEFF Research Database (Denmark)

    Siddique, Mohammad Abdul Momin; Linhart, Otomar; Krejszeff, Sławomir;

    2017-01-01

    Paternal, compared to maternal, contributions were believed to have only a limited influence on embryonic development and larval fitness traits in fishes. Therefore, the perspective of male influence on early life history traits has come under scrutiny. This study was conducted to determine paren...... into consideration for reproduction of these and likely other economically important fish species.......Paternal, compared to maternal, contributions were believed to have only a limited influence on embryonic development and larval fitness traits in fishes. Therefore, the perspective of male influence on early life history traits has come under scrutiny. This study was conducted to determine...

  5. Notes concerning the distribution of Asian fish species, Pseudorasbora parva, in Europe

    OpenAIRE

    Claudiu Gavriloaie; Laurenţiu Burlacu; Cecilia Bucur; Corina Berkesy

    2014-01-01

    In this paper we discuss about the origin and distribution of a gobionin fish species, the topmouth gudgeon (Pseudorasbora parva) in the inland waters of Europe. This species was introduced in our continent for the first time in Romania in 1961 and in Albania, probably in 1960, direct from China. Later, the topmouth gudgeon spread extremely fast in almost the whole Europe, only in a few countries the species being so far absent. In the most cases, this spreading was possible due t...

  6. Reproductive characteristics of characid fish species (Teleostei, Characiformes) and their relationship with body size and phylogeny

    OpenAIRE

    Azevedo,Marco A.

    2010-01-01

    In this study, I investigated the reproductive biology of fish species from the family Characidae of the order Characiformes. I also investigated the relationship between reproductive biology and body weight and interpreted this relationship in a phylogenetic context. The results of the present study contribute to the understanding of the evolution of the reproductive strategies present in the species of this family. Most larger characid species and other characiforms exhibit a reproductive p...

  7. Fatty acid metabolism in fish species as a biomarker for environmental monitoring.

    Science.gov (United States)

    Olivares-Rubio, Hugo F; Vega-López, Armando

    2016-11-01

    Pollution by Organic Contaminants (OC) in aquatic environments is a relevant issue at the global scale. Lipids comprised of Fatty Acids (FA) play many important roles in the physiology and life history of fishes. Toxic effects of OC are partly dependent on its bioaccumulation in the lipids of aquatic organisms due its physicochemical properties. Therefore, there is an increasing interest to investigate the gene expression as well as the presence and activity of proteins involved in FA metabolism. The attention on Peroxisome Proliferation Activate Receptors (PPARs) also prevails in fish species exposed to OC and in the transport, biosynthesis and β-oxidation of FA. Several studies have been conducted under controlled conditions to evaluate these biological aspects of fish species exposed to OC, as fibrates, endocrine disrupting compounds, perfluoroalkyl acids, flame retardants, metals and mixtures of organic compounds associated with a polluted area. However, only fibrates, which are agonists of PPARs, induce biological responses suitable to be considered as biomarkers of exposure to these pollutants. According to the documented findings on this topic, it is unlikely that these physiological aspects are suitable to be employed as biomarkers with some noticeable exceptions, which depend on experimental design. This emphasises the need to investigate the responses in fish treated with mixtures of OC and in wild fish species from polluted areas to validate or refute the suitability of these biomarkers for environmental or fish health monitoring.

  8. Nutritive values of some food plants, fresh and processed fish species

    Directory of Open Access Journals (Sweden)

    Ali Aberoumand

    2015-12-01

    Full Text Available The chemical composition of four edible plant foods species, three fish species and one prawn were analyzed in Food Chemistry Laboratory of Behbahan Khatam Alanbia University of Technology, Behbahan, Iran in 2014. The analysis of fatty acid and sugars composition were performed by gas liquid chromatography and high performance liquid chromatography, respectively. Protein and lipid content were founded higher in baked and fried in fish S. commersonnianus (74.29%, (20.20%, fish Sphyraena helleri (88.12% and (17.77%, respectively. Ash content in fish S. commersonnianus varies from 9.80% to 15.34%, and in fish S. helleri from 5.83% to 7.68%. Based on the proximate analysis, it can be calculated that an edible portion of 100 g of studied edible plant foods provides, on average, around 303.9±1.04 kcal. The plant Portulaca neglecta is suitable for high temperature food processes. The macronutrient profile in general revealed that the wild plant foods were with rich sources of protein and carbohydrates, and had low amounts of fat. The highest protein, the lowest fat and energy contents were found in boiled in both fish species; therefore, boiling can be recommended as the best cooking method for healthy diet.

  9. Biomagnification of DDT and its metabolites in four fish species of a tropical lake.

    Science.gov (United States)

    Deribe, Ermias; Rosseland, Bjørn Olav; Borgstrøm, Reidar; Salbu, Brit; Gebremariam, Zinabu; Dadebo, Elias; Skipperud, Lindis; Eklo, Ole Martin

    2013-09-01

    The concentrations and biomagnifications of dichlorodiphenyltrichloroethane (DDT) and its metabolites were examined in four fish species (Clarias gariepinus, Oreochromis niloticus, Tilapia zillii, and Carassius auratus) from Lake Ziway, Rift Valley, Ethiopia. Paired stomach content analysis, and stable isotope ratio of nitrogen (δ(15)N, ‰) and carbon (δ(13)C, ‰) were used to study the trophic position of the fish species in the lake. 4,4'-DDE, 4,4'-DDT and 4,4'-DDD were the main DDTs identified in the fish samples, with 4,4'-DDE as the most predominant metabolite, with mean concentration ranging from 1.4 to 17.8 ng g(-1) wet weight (ww). The concentrations of DDTs found in fish from Lake Ziway were, in general lower than those found in most studies carried out in other African Lakes. However, the presence of DDT in all tissue samples collected from all fish species in the lake indicates the magnitude of the incidence. Moreover, the observed mean 4,4'-DDE to 4,4'-DDT ratio below 1 in C. auratus from Lake Ziway may suggest a recent exposure of these species to DDT, indicating that a contamination source is still present. 4,4'-DDE was found to biomagnify in the fish species of the lake, and increases with trophic level, however, the biomagnification rate was generally lower than what has been reported from other areas. Significantly higher concentrations of 4,4'-DDE were found in the top consumer fish in Lake Ziway, C. gariepinus than in O. niloticus (t=2.6, P<0.01), T. zillii (t=2.5, P<0.02) and C. auratus (t=2.2, P<0.03).

  10. Methylmercury levels in predatory fish species marketed in Canada.

    Science.gov (United States)

    Forsyth, Don S; Casey, V; Dabeka, R W; McKenzie, A

    2004-09-01

    Mercury was detected in all analysed samples of swordfish, marlin, shark and tuna purchased from major supermarket outlets and fish retailers in three cities across Canada. Total mercury and methylmercury levels ranged up to 3845 and 2346 ng g(-1), respectively. Swordfish contained the highest levels, followed by shark, fresh/frozen tuna and marlin. Levels in canned tuna were considerably less than the other examined samples. Methylmercury was extracted with toluene from enzymatically hydrolysed samples after the addition of sulphuric acid and potassium bromide. An L-cysteine back-extraction was used to separate the methylmercury from most organic co-extractives. Analysis of methylmercury (as methylmercury bromide) was by gas chromatography with pulsed discharge detection.

  11. Fish species substitution and misnaming in South Africa: An economic, safety and sustainability conundrum revisited.

    Science.gov (United States)

    Cawthorn, Donna-Mareè; Duncan, John; Kastern, Chris; Francis, Junaid; Hoffman, Louwrens C

    2015-10-15

    While fish species mislabelling has emerged as a global problem, the tracking of improvements or deteriorations in seafood trading practices is challenging without a consistent basis for monitoring. The aim of this study was to develop a robust, repeatable species authentication protocol that could be used to benchmark the current and future incidences of fish mislabelling in South Africa. Using this approach, 149 fish samples collected from restaurants and retailers in three provinces (KwaZulu-Natal, Western Cape and Gauteng) were identified using DNA barcoding, supplemented in certain cases with mitochondrial control region sequencing. Overall, 18% of samples were incorrectly described in terms of species, with similar misrepresentation rates in restaurants (18%) and retail outlets (19%). While there appears to be some improvement in the transparency of local seafood marketing compared to previous studies, the results remain of concern and signal the need for enhanced seafood labelling regulations, monitoring and law enforcement.

  12. Facilitation and Dominance in a Schooling Predator: Foraging Behavior of Florida Pompano, Trachinotus carolinus.

    Directory of Open Access Journals (Sweden)

    Meagan N Schrandt

    Full Text Available Presumably an individual's risk of predation is reduced by group membership and this 'safety in numbers' concept has been readily applied to investigations of schooling prey; however, foraging in groups may also be beneficial. We tested the hypothesis that, when feeding in groups, foraging of a coastal fish (Florida Pompano, Trachinotus carolinus on a benthic prey source would be facilitated (i.e. fish feeding in groups will consume more prey items. Although this question has been addressed for other fish species, it has not been previously addressed for Florida Pompano, a fish known to exhibit schooling behavior and that is used for aquaculture, where understanding the feeding ecology is important for healthy and efficient grow-out. In this experiment, juvenile Florida Pompano were offered a fixed number of coquina clams (Donax spp. for one hour either in a group or as individuals. The following day they were tested in the opposite configuration. Fish in groups achieved greater consumption (average of 26 clams consumed by the entire group than the individuals comprising the group (average of 14 clams consumed [sum of clams consumed by all individuals of the group]. Fish in groups also had fewer unsuccessful foraging attempts (2.75 compared to 4.75 hr(-1 and tended to have a shorter latency until the first feeding activity. Our results suggest fish in groups were more comfortable feeding and more successful in their feeding attempts. Interestingly, the consumption benefit of group foraging was not shared by all--not all fish within a group consumed equal numbers of clams. Taken together, the results support our hypothesis that foraging in a group provides facilitation, but the short-term benefits are not equally shared by all individuals.

  13. Trace elements in muscle of three fish species from Todos os Santos Bay, Bahia State, Brazil.

    Science.gov (United States)

    de Santana, Carolina Oliveira; de Jesus, Taíse Bomfim; de Aguiar, William Moura; de Jesus Sant'anna Franca-Rocha, Washington; Soares, Carlos Alberto Caroso

    2017-03-01

    In this study, an analysis was performed on the concentrations of the trace elements Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn in muscle of two carnivorous and one planktivorous fish species collected at Todos os Santos Bay (BTS). The accumulation order of the trace elements in Lutjanus analis was Al >Zn >Fe >Cr >Ba >Ni. In Cetengraulis edentulus, the order was Al >Fe >Zn >Cr >Ni >Mn >As. In the species Diapterus rhombeus, the order was Al >Fe >Zn >Cr >Ni >Mn >Cd. To determine the risk related to the consumption of fish, toxicity guidelines were used as standard references. It was observed that the species C. edentulus contained concentrations of As exceeding WHO limits, but these concentrations were acceptable according to the Agência Nacional de Vigilância Sanitária (ANVISA) guidelines. Cd levels were found only in D. rhombeus and in low concentrations according to the determinations of WHO and ANVISA. Pb levels were not detected in any of the three fish species. The analyzed elements did not differ statistically according to the species and feeding habits. The results point to possible risks of human contamination by As related to the consumption of the fish species C. edentulus from the BTS.

  14. [Bycatch fish species from shrimp industrial fishery in the Gulf of California, Mexico].

    Science.gov (United States)

    López-Martínez, Juana; Herrera-Valdivia, Eloisa; Rodríguez-Romero, Jesús; Hernández-Vázquez, Sergio

    2010-09-01

    Bycatch fish species from shrimp industrial fishery in the Gulf of California, Mexico. The shrimp fishery in the Gulf of California is one the most important activities of revenue and employment for communities. Nevertheless, this fishery has also created a large bycatch problem, principally fish. To asses this issue, a group of observers were placed on board the industrial shrimp fleet and evaluated the Eastern side of the Gulf during 2004 and 2005. Studies consisted on 20kg samples of the capture for each trawl, and made possible a systematic list of species for this geographic area. Fish represented 70% of the capture. A total of 51 101 fish were collected, belonging to two classes, 20 orders, 65 families, 127 genera, and 241 species. The order Perciformes was the most diverse with 31 families, 78 genera, and 158 species. The best represented families by number of species were: Sciaenidae (34) and Paralichthyidae (18) and Haemulidae and Carangidae (16 each). The best represented genera in number of species were Symphurus (nine) and Diplectrum and Cynoscion (six); other important genera were Larimus and Porichthys with five species each. The best represented species in number were Syacium ovale, Pseudupeneus grandisquamis, Haemulopsis nitidos, Diplectrum pacificum, Synodus scituliceps, Balistes polylepis, Eucinostomus currani, Eucinostomus gracilis, Porichthys analis, Chloroscombrus orqueta, Selene peruviana, Orthopristis reddingi, Etropus crossotus, Scorpaena sonorae and Urobatis halleri. The number of recorded species is notably high, compared with demersal fauna of other areas of the Mexican Pacific, such as Gulf of Tehuantepec (178), Nayarit, Michoacán, Guerrero (174, 120 and 166), Jalisco and Colima (161 species), and those of the Western coast of the Baja California Peninsula (220 species).

  15. Trimethylamine oxide, dimethylamine, trimethylamine and formaldehyde levels in main traded fish species in Hong Kong.

    Science.gov (United States)

    Chung, S W C; Chan, B T P

    2009-01-01

    Levels of trimethylamine oxide (TMAO), dimethylamine (DMA), trimethylamine (TMA) and formaldehyde (FA) were studied in 266 different fishes, including fresh/frozen raw whole fishes of 89 different species that traded in Hong Kong, China. Determination of TMAO can confirm the source of DMA and FA if present in the sample. These samples were purchased from different commercial outlets between April and August 2007. All samples of raw whole fish were identified for their species by the Agriculture, Fisheries and Conservation Department. The content of TMAO was determined by high-performance liquid chromatography (HPLC) coupled with a chemiluminescent nitrogen detector. The possible decomposition products of TMAO, DMA and TMA were analysed by headspace solid-phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC-MS), while FA was conducted by steam distillation then quantified by a HPLC. The range for TMAO of all samples was <5-3800 mg kg(-1) with median of 970 mg kg(-1), while the endogenous enzymatic cleavage products DMA, TMA and FA were in the range of <2-320, <1-190 and <1-160 mg kg(-1), respectively. These cleavage products were mainly found in three fish species, Harpadon nehereus, Saurida elongata and Saurida tumbil, that belong to the family Synodontidae (Lizardfishes) and subfamily Harpadontinae. Besides, freshwater fish species, namely, Micropterus salmoides, Oreochromis niloticus niloticus and Siniperca chuatsi, were found to contain TMAO in the range of 510-760, 85-720 and 400-640 mg kg(-1), respectively.

  16. Fish, fans and hydroids: host species of pygmy seahorses

    Science.gov (United States)

    Reijnen, Bastian T.; van der Meij, Sancia E.T.; van Ofwegen, Leen P.

    2011-01-01

    Abstract An overview of the octocoral and hydrozoan host species of pygmy seahorses is provided based on literature records and recently collected field data for Hippocampus bargibanti, Hippocampus denise and Hippocampus pontohi. Seven new associations are recognized and an overview of the so far documented host species is given. A detailed re-examination of octocoral type material and a review of the taxonomic history of the alcyonacean genera Annella (Subergorgiidae) and Muricella (Acanthogorgiidae) are included as baseline for future revisions. The host specificity and colour morphs of pygmy seahorses are discussed, as well as the reliability of (previous) identifications and conservation issues. PMID:21747677

  17. Social learning of an associative foraging task in zebrafish

    Science.gov (United States)

    Zala, Sarah M.; Määttänen, Ilmari

    2013-05-01

    The zebrafish ( Danio rerio) is increasingly becoming an important model species for studies on the genetic and neural mechanisms controlling behaviour and cognition. Here, we utilized a conditioned place preference (CPP) paradigm to study social learning in zebrafish. We tested whether social interactions with conditioned demonstrators enhance the ability of focal naïve individuals to learn an associative foraging task. We found that the presence of conditioned demonstrators improved focal fish foraging behaviour through the process of social transmission, whereas the presence of inexperienced demonstrators interfered with the learning of the control focal fish. Our results indicate that zebrafish use social learning for finding food and that this CPP paradigm is an efficient assay to study social learning and memory in zebrafish.

  18. Social learning of an associative foraging task in zebrafish.

    Science.gov (United States)

    Zala, Sarah M; Määttänen, Ilmari

    2013-05-01

    The zebrafish (Danio rerio) is increasingly becoming an important model species for studies on the genetic and neural mechanisms controlling behaviour and cognition. Here, we utilized a conditioned place preference (CPP) paradigm to study social learning in zebrafish. We tested whether social interactions with conditioned demonstrators enhance the ability of focal naïve individuals to learn an associative foraging task. We found that the presence of conditioned demonstrators improved focal fish foraging behaviour through the process of social transmission, whereas the presence of inexperienced demonstrators interfered with the learning of the control focal fish. Our results indicate that zebrafish use social learning for finding food and that this CPP paradigm is an efficient assay to study social learning and memory in zebrafish.

  19. Experimental infection of Aphanomyces invadans and susceptibility in seven species of tropical fish

    Science.gov (United States)

    Afzali, Seyedeh F.; Mohd Daud, Hassan Hj.; Sharifpour, Issa; Afsharnasab, Mohammad; Shankar, Shiv

    2015-01-01

    Aim: Epizootic ulcerative syndrome (EUS) causes by aquatic oomycete fungus, Aphanomyces invadans is a dangerous fish disease of a wide range of fresh and brackish water, wild and farmed fish throughout the world. The objective of the present study was to determine the susceptibility of a number of tropical fish species to the EUS and compare the severity of infection between experimental groups. Materials and Methods: Snakehead, Channa striata (Bloch, 1793); snakeskin gourami, Trichopodus pectoralis (Regan, 1910); koi carp, Cyprinus carpio (Linnaeus, 1758); broadhead catfish, Clarias macrocephalus (Günther, 1864); goldfish, Carassius auratus (Linnaeus, 1758); climbing perch, Anabas testudineus (Bloch, 1792); and Nile tilapia, Oreochromis niloticus (Linnaeus, 1758) were challenged by intramuscular injection using zoospores of Aphanomyces invadans (NJM9701). The infected fish skins and muscles were examined for EUS histopathological characteristics, and the results on the severity of lesions and mortality were analyzed using SPSS program. Results: All zoospore-injected fish were shown to be susceptible to the EUS infection except Nile tilapia. Although, the general histopathological pattern was similar in the zoospore-injected group, but there were some variation in granulomatous reaction, that is the presence or absence of giant cells, and time of mortality were detected. The result of statistical analysis showed that there was a significant difference between species, (c2=145.11 and p<0.01). Conclusion: Gourami, koi carp, and catfish were demonstrated to be highly susceptible while goldfish and climbing perch were found to be moderately susceptible to the EUS infection. These findings suggested that the cellular response of fish to mycotic infection and granulomatous reaction varied in different fish species, which could not be an indicator of susceptibility or resistant to the EUS itself, although it was shown that the granulation rate and the level of maturity

  20. Experimental infection of Aphanomyces invadans and susceptibility in seven species of tropical fish

    Directory of Open Access Journals (Sweden)

    Seyedeh F. Afzali

    2015-09-01

    Full Text Available Aim: Epizootic ulcerative syndrome (EUS causes by aquatic oomycete fungus, Aphanomyces invadans is a dangerous fish disease of a wide range of fresh and brackish water, wild and farmed fish throughout the world. The objective of the present study was to determine the susceptibility of a number of tropical fish species to the EUS and compare the severity of infection between experimental groups. Materials and Methods: Snakehead, Channa striata (Bloch, 1793; snakeskin gourami, Trichopodus pectoralis (Regan, 1910; koi carp, Cyprinus carpio (Linnaeus, 1758; broadhead catfish, Clarias macrocephalus (Günther, 1864; goldfish, Carassius auratus (Linnaeus, 1758; climbing perch, Anabas testudineus (Bloch, 1792; and Nile tilapia, Oreochromis niloticus (Linnaeus, 1758 were challenged by intramuscular injection using zoospores of Aphanomyces invadans (NJM9701. The infected fish skins and muscles were examined for EUS histopathological characteristics, and the results on the severity of lesions and mortality were analyzed using SPSS program. Results: All zoospore-injected fish were shown to be susceptible to the EUS infection except Nile tilapia. Although, the general histopathological pattern was similar in the zoospore-injected group, but there were some variation in granulomatous reaction, that is the presence or absence of giant cells, and time of mortality were detected. The result of statistical analysis showed that there was a significant difference between species, (c2=145.11 and p<0.01. Conclusion: Gourami, koi carp, and catfish were demonstrated to be highly susceptible while goldfish and climbing perch were found to be moderately susceptible to the EUS infection. These findings suggested that the cellular response of fish to mycotic infection and granulomatous reaction varied in different fish species, which could not be an indicator of susceptibility or resistant to the EUS itself, although it was shown that the granulation rate and the level of

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

    Directory of Open Access Journals (Sweden)

    Derbel H.

    2012-05-01

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

  2. Seven species of Pseudopecoeloides Yamaguti, 1940 (Digenea, Opecoelidae from temperate marine fishes of Australia, including five new species

    Directory of Open Access Journals (Sweden)

    Thelma Aken’Ova

    2009-02-01

    Full Text Available Seven species of Pseudopecoeloides including five new are described from marine fishes in the waters off the coasts of Queensland, and West and South Australia. The new species are Pseudopecoeloides hickmani n. sp. from Pseudocaranx wrighti (Carangidae, P. lesteri n. sp. from Pseudocaranx dentex and Pseudocaranx wrighti, P. arripi n. sp. from Arripis georgianus (Arripidae, P. atherinomori n. sp. from Atherinonmorus ogilbyi (Atherinidae, P, hafeezullahi n. sp. from Trachurus novaezealandiae (Carangidae. Pseudopecoeloides scomberi Hafeezullah, 1971, which was transferred to Opecoeloides (Odhner, 1928 by Madhavi (1975 is reported from Scomberoides lysan (Carangidae and returned to Pseudopecoeloides. Pseudopecoeloides tenuis Yamaguti, 1940 is reported from a new host species, Priacanthus macracanthus (Priacanthidae.

  3. Nutritional Properties of Some Novel Selected Fish Species in Khuzestan Province, Iran

    OpenAIRE

    Ali Aberoumand

    2014-01-01

    The proximate biochemical contents of some fish species i. e. Thunnus alalunga, Evynnis japonica, Caulerpa lentillifera, Orcynopsis unicolor and Euthynnus affinis were analyzed. Protein contents was determined in T. alalunga (22 %), E. japonica (13.02%), C.lentillifera (26.9%), O. unicolor (22%) and in E. affinis (24%) respectively. Fat content was recorded as 23.3%, 0.24%, 15%, 16% and 14% respectively in the five species of fish. The ash content was highest in C. lentillifera (8.8%). The pr...

  4. Anticholinesterase effect of eserine (physostigmine in fish and crustacean species

    Directory of Open Access Journals (Sweden)

    José M. Monserrat

    2001-03-01

    Full Text Available The kinetic characteristic (Km of cholinesterase from the crab Chasmagnathus granulata, the shrimp Farfantepenaeus paulensis and the fish Odontesthes bonaeriensis were compared and correlated with the anticholinesterasic effect of eserine (physostigmine. For the crustaceans, the estimated Km values were about 5-8 times higher than that estimated for the fish (0.04 mM. In the crab and the shrimp, the concentration of eserine which inhibited 50% of cholinesterase activity (IC50 was estimated as 5.33x10-4 and 4.33x10-4 mM, respectively. In both cases, it was significantly higher (P As caraterísticas cinéticas (Km de colinesterases do caranguejo Chasmagnathus granulata, o camarão Farfantepenaeus paulensis e o peixe Odontesthes bonaeriensis foram comparadas e correlacionadas com os efeitos anticolinesterásicos da eserina (fisostigmina. Nos crustáceos, o valores estimados de Km foram aproximadamente 5-8 vezes maiores do que aquele estimado para a espécie de peixe (0.04 mM. No caranguejo e camarão, a concentração de eserina que inibiu 50% da atividade colinesterásica (CI50 foi estimada em 5.33x10-4 e 4.33x10-4 mM, respectivamente. Estes valores foram significativamente maiores (P < 0.05 que aquele estimado para as larvas de peixes (7.43x10-5 mM. Um valor de Km mais elevado poderia refletir uma menor afinidade da colinesterase pelo seu substrato natural, acetilcolina, ou análogos tais como inseticidas carbamatos e fosforados. Se a CI50 para eserina é considerada como um índice da susceptibilidade da enzima a inibição por inseticidas, logo a colinesterase de larvas de peixes poderiam ser uma ferramenta mais útil no monitoramento de inseticidas do que aquelas das espécies de crustáceos.

  5. The influence of arbuscular mycorrhizae on root precision nutrient foraging of two pioneer plant species during early reclamation

    Science.gov (United States)

    Boldt-Burisch, Katja; Naeth, M. Anne

    2017-04-01

    On many post mining sites in the Lusatian Mining District (East Germany) soil heterogeneity consists of sandy soil with embedded clay-silt fragments. Those clays silt fragments might act as nutrient hotspots. Arbuscular mycorrhizal fungi in an infertile ecosystem could enhance a plant's ability to selectively forage for those nutrients and thus to improve plants nutrient supply. In our study we investigated whether silt-clay fragments within a sandy soil matrix induced preferential root growth of Lotus corniculatus and Calamagrostis epigeios, whether arbuscular mycorrhizae influenced root foraging patterns, and to what extent selective rooting in clay silt fragments influenced plant growth were addressed in this research. Soil types were sterile and non-sterile sandy soil and clay-silt fragments. Treatments were with and without arbuscular mycorrhizae, with and without soil solution, and soil solution and mycorrhizal inoculum combined. Root biomass, root density and intraradical fungal alkaline phosphatase activity and frequency were determined in fragments relative to sandy soil. Furthermore, temporal relationship of number of roots in fragments and plant height was assessed. Lotus corniculatus showed strong selective rooting into fragments especially with those plants treated with commercial cultivated arbuscular mycorrhizae; Calamagrostis epigeios did not. Without arbuscular mycorrhizae, L. corniculatus growth was significantly reduced and selective rooting did not occur. Selective rooting induced significant growth spurts of L. corniculatus. Roots in fragments had higher fungal alkaline phosphatase activity suggesting that mycorrhizal efficiency and related plants phosphorus supply is enhanced in roots in fragments. The application of cultivated arbuscular mycorrhizal fungi significantly and quickly influenced root foraging patterns, especially those of L. corniculatus, suggesting mycorrhizae may also enhance the ability of other plants to selectively forage

  6. Testing the influence of environmental heterogeneity on fish species richness in two biogeographic provinces

    Directory of Open Access Journals (Sweden)

    Philippe Massicotte

    2015-02-01

    Full Text Available Environmental homogenization in coastal ecosystems impacted by human activities may be an important factor explaining the observed decline in fish species richness. We used fish community data (>200 species from extensive surveys conducted in two biogeographic provinces (extent >1,000 km in North America to quantify the relationship between fish species richness and local (grain <10 km2 environmental heterogeneity. Our analyses are based on samples collected at nearly 800 stations over a period of five years. We demonstrate that fish species richness in coastal ecosystems is associated locally with the spatial heterogeneity of environmental variables but not with their magnitude. The observed effect of heterogeneity on species richness was substantially greater than that generated by simulations from a random placement model of community assembly, indicating that the observed relationship is unlikely to arise from veil or sampling effects. Our results suggest that restoring or actively protecting areas of high habitat heterogeneity may be of great importance for slowing current trends of decreasing biodiversity in coastal ecosystems.

  7. Trophodynamics and diet overlap of small pelagic fish species in the Bay of Biscay

    KAUST Repository

    Bachiller, E

    2015-08-27

    Small pelagic fish are the link between planktonic production and higher trophic levels. Competition for resources may play a role in the population dynamics of species, some of them probably standing out from the others due to greater feeding success. It is therefore important to understand the trophic niche of species overlapping both spatially and temporally. In this study, we have investigated the diet, prey preference, trophic niche breadth and diet overlap of the 8 major small pelagic species (anchovy, sardine, sprat, Atlantic and Mediterranean horse mackerel, bogue, Atlantic mackerel and Atlantic chub mackerel) inhabiting the Bay of Biscay. Results indicate that all fish feed mainly on calanoid copepods, incorporating larger prey like euphausiids and decapods to complete their diet. Differences in ingested prey diversity seem to be more limited by the available zooplankton at sea than by a specific diet preference by fish species, resulting in an overall high diet overlap, especially within clupeids but also between clupeids and other (larger) predator species. Consumption estimations for different prey groups could therefore determine whether such a large diet overlap between small pelagic fish, together with spatial co-occurrence, results in competition or enhances the effects of intraguild predation, which is important in terms of an ecosystem approach to fisheries management.

  8. Characterization factors for water consumption and greenhouse gas emissions based on freshwater fish species extinction.

    Science.gov (United States)

    Hanafiah, Marlia M; Xenopoulos, Marguerite A; Pfister, Stephan; Leuven, Rob S E W; Huijbregts, Mark A J

    2011-06-15

    Human-induced changes in water consumption and global warming are likely to reduce the species richness of freshwater ecosystems. So far, these impacts have not been addressed in the context of life cycle assessment (LCA). Here, we derived characterization factors for water consumption and global warming based on freshwater fish species loss. Calculation of characterization factors for potential freshwater fish losses from water consumption were estimated using a generic species-river discharge curve for 214 global river basins. We also derived characterization factors for potential freshwater fish species losses per unit of greenhouse gas emission. Based on five global climate scenarios, characterization factors for 63 greenhouse gas emissions were calculated. Depending on the river considered, characterization factors for water consumption can differ up to 3 orders of magnitude. Characterization factors for greenhouse gas emissions can vary up to 5 orders of magnitude, depending on the atmospheric residence time and radiative forcing efficiency of greenhouse gas emissions. An emission of 1 ton of CO₂ is expected to cause the same impact on potential fish species disappearance as the water consumption of 10-1000 m³, depending on the river basin considered. Our results make it possible to compare the impact of water consumption with greenhouse gas emissions.

  9. Nitrogen and carbohydrate fractions on Tifton-85 pastures overseeded with annual winter and summer forage species in different seasons

    Directory of Open Access Journals (Sweden)

    Andréia Luciane Moreira

    2012-09-01

    Full Text Available An experiment was conducted during the 2001-2002 winter-spring-summer to determine the nitrogen and carbohydrate fractions in Tifton-85 pastures exclusively or overseeded with oats, millet and sorghum-sudangrass hybrids. The treatments were Tifton-85 overseeded with millet + bristle oat; sorghum-sudangrass + bristle oat, on 06/19/2002 and 07/02/2002, respectively; and Tifton-85 (Control. The experiment was conducted in a randomized block design with three replications. Nitrogen and carbohydrate fractions were affected by the nitrogen and total carbohydrate contents observed in the pasture overseeded at different seeding times, and by the different growth periods. The highest nitrogen fractions (A + B1 were observed in the early growth periods. Overseeding affected the forage nitrogen and carbohydrate fraction contents positively. The high solubility of both carbohydrate and protein from millet + bristle oat and bristle oat + sorghum-sudangrass mixtures indicates the quality of these forages and their potential use as an important supplement in forage systems based on tropical pastures.

  10. Cadmium concentration in three species of freshwater fishes from Keuretoe River, Northern Aceh, Indonesia

    Directory of Open Access Journals (Sweden)

    Muhammad A. Sarong

    2013-09-01

    Full Text Available The objectives of present study was to evaluate cadmium (Cd concentration in some freshwater fishes found in Keuretoe Rivers and to determine the most effective freshwater fishes (Osphronemus goramy, Anguilla marmorata and Hemibagrus nemurus in accumulating of cadmium. A total of three sampling locations were determined using the purposive of random sampling. A total of three individual fishes at every sampling location were collected, the tissues were processed for Atomic Absorption Spectrophotometry (AAS and data were analyzed by Anova followed by Duncan multiple range test. The result revealed that the cadmium concentration ranges between 0.0064 ppm and 0.0260 ppm. Anova test showed that the sampling locations did not significantly affect the cadmium accumulation in fishes, but the fish species gave significantly effect on the cadmium accumulation in their tissue. The Duncan test showed that high cadmium accumulation was found in gourami at Station 2 and in mottled eel at Station 1, the concentrations were significantly different from Cd content in bagrid catfish at all sampling locations. The higher of cadmium pollution was recorded in Station 3 and gourami accumulated higher cadmium than other fishes studied. Keuretoe River is contaminated with cadmium and the fishes should not be consumed.

  11. Fish species identification based on its acoustic target strength using in situ measurement

    Directory of Open Access Journals (Sweden)

    Raja-Bidin Raja-Hassan

    2010-11-01

    Full Text Available The purpose of this study is fish species identification using acoustic target strength (TS. Insitu measurement has been deployed at the South China Sea of Terengganu Malaysia using Furuno FQ-80 Scientific Echo Sounder which included in the research vessel of KK Senangin II. The transducer isplaced 2.8 meter under sea surface while fish put in the net cage under the vessel. TS data have beencollected independently for commercial fish in Malaysia, there are Selar boops (Oxeye scad, Alepesdjedaba (Shrimp scad, Megalaspis cordyla (Torpedo scad, and Decapterus maruadsi/b> (Japanese scad.TS value, depth, and position of specific target have been observed using echogram. TS of every speciesis different although similar size and at the similar range from transducer. Thus, the specific fish specieshas been identified based on its acoustic target strength.

  12. Functional invertebrate prey groups reflect dietary responses to phenology and farming activity and pest control services in three sympatric species of aerially foraging insectivorous birds.

    Directory of Open Access Journals (Sweden)

    Grzegorz Orłowski

    Full Text Available Farming activity severely impacts the invertebrate food resources of farmland birds, with direct mortality to populations of above-ground arthropods thorough mechanical damage during crop harvests. In this study we assessed the effects of phenological periods, including the timing of harvest, on the composition and biomass of prey consumed by three species of aerial insectivorous birds. Common Swifts Apus apus, Barn Swallows Hirundo rustica and House Martins Delichon urbica breed sympatrically and most of their diet is obtained from agricultural sources of invertebrate prey, especially from oil-seed rape crops. We categorized invertebrate prey into six functional groups, including oil-seed rape pests; pests of other arable crops; other crop-provisioned taxa; coprophilous taxa; and taxa living in non-crop and mixed crop/non-crop habitats. Seasonality impacted functional groups differently, but the general direction of change (increase/decrease of all groups was consistent as indexed by prey composition of the three aerial insectivores studied here. After the oil-seed rape crop harvest (mid July, all three species exhibited a dietary shift from oil-seed rape insect pests to other aerial invertebrate prey groups. However, Common Switfts also consumed a relative large quantity of oil-seed rape insect pests in the late summer (August, suggesting that they could reduce pest insect emigration beyond the host plant/crop. Since these aerially foraging insectivorous birds operate in specific conditions and feed on specific pest resources unavailable to foliage/ground foraging avian predators, our results suggest that in some crops like oil-seed rape cultivations, the potential integration of the insectivory of aerial foraging birds into pest management schemes might provide economic benefits. We advise further research into the origin of airborne insects and the role of aerial insectivores as agents of the biological control of crop insect pests

  13. Functional invertebrate prey groups reflect dietary responses to phenology and farming activity and pest control services in three sympatric species of aerially foraging insectivorous birds.

    Science.gov (United States)

    Orłowski, Grzegorz; Karg, Jerzy; Karg, Grzegorz

    2014-01-01

    Farming activity severely impacts the invertebrate food resources of farmland birds, with direct mortality to populations of above-ground arthropods thorough mechanical damage during crop harvests. In this study we assessed the effects of phenological periods, including the timing of harvest, on the composition and biomass of prey consumed by three species of aerial insectivorous birds. Common Swifts Apus apus, Barn Swallows Hirundo rustica and House Martins Delichon urbica breed sympatrically and most of their diet is obtained from agricultural sources of invertebrate prey, especially from oil-seed rape crops. We categorized invertebrate prey into six functional groups, including oil-seed rape pests; pests of other arable crops; other crop-provisioned taxa; coprophilous taxa; and taxa living in non-crop and mixed crop/non-crop habitats. Seasonality impacted functional groups differently, but the general direction of change (increase/decrease) of all groups was consistent as indexed by prey composition of the three aerial insectivores studied here. After the oil-seed rape crop harvest (mid July), all three species exhibited a dietary shift from oil-seed rape insect pests to other aerial invertebrate prey groups. However, Common Switfts also consumed a relative large quantity of oil-seed rape insect pests in the late summer (August), suggesting that they could reduce pest insect emigration beyond the host plant/crop. Since these aerially foraging insectivorous birds operate in specific conditions and feed on specific pest resources unavailable to foliage/ground foraging avian predators, our results suggest that in some crops like oil-seed rape cultivations, the potential integration of the insectivory of aerial foraging birds into pest management schemes might provide economic benefits. We advise further research into the origin of airborne insects and the role of aerial insectivores as agents of the biological control of crop insect pests, especially the

  14. Levels of organochlorine pesticides, polychlorinated biphenyls and polybrominated diphenyl ethers in fish species from Kahramanmaras, Turkey.

    Science.gov (United States)

    Erdogrul, Ozlem; Covaci, Adrian; Schepens, Paul

    2005-07-01

    The levels of organohalogenated contaminants, such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were measured in four fish species (Acanthobrama marmid (kalashpa), Cyprinus carpio (carp), Chondrostoma regium (nose-carp), and Silurus glanis (wels)) from the Sir Dam Lake, Kahramanmaras, Turkey. These species were selected for their characteristic feeding behaviour and their importance to local human fish consumption. DDTs were the predominant organohalogenated contaminants in all species, with the p,p'-DDE contributing to more than 90% to the total DDTs. Other OCPs, such as hexachlorocyclohexane (HCH) isomers, chlordanes and hexachlorobenzene (HCB) were found at much lower levels in all five species. The levels of PCBs and PBDEs (on wet weight basis) were lower than in similar species from European or American freshwater systems. PBDE data were measured for the first time in fish species from Turkish environment. Lipid-based concentrations of OCPs, PCBs and PBDEs were higher in wels than in the other species and this was related to its piscivorous feeding mode and to its higher lipid content. Contrarily, concentrations of pollutants in nose-carp were the lowest, in agreement with its more herbivorous diet. A preferential accumulation in muscle compared to liver was observed for all OCPs, PCBs, and PBDEs in wels and carp, while in nose-carp, a preferential accumulation in liver was observed only for PBDEs, p,p'-DDT and PCBs. Racemic amounts for alpha-HCH were measured in all investigated muscle and liver samples, except for carp muscle.

  15. Floods and fish : recruitment and distribution of fish in the Volga River floodplain

    NARCIS (Netherlands)

    Górski, K.

    2010-01-01

    Natural river floodplains are among the most diverse and productive ecosystems on Earth and provide key habitats for foraging, spawning and as a nursery for many riverine fish species. Periodic flooding plays a principal role in the ecological processes in floodplain systems resulting in high produc

  16. SNP Discovery In Marine Fish Species By 454 Sequencing

    DEFF Research Database (Denmark)

    Panitz, Frank; Nielsen, Rasmus Ory; van Houdt, Jeroen K J

    2011-01-01

    (Solea solea). For each species, a total of 7-8 individuals from 4-5 populations, that in most cases spanned major parts of the species’ distributions, were individually tagged and subsequently pooled for cDNA library construction. After 454 sequencing reads were de-multiplexed, cleaned, repeat...... using GigaBayes (http://bioinformatics.bc.edu/marthlab/GigaBayes). From the predicted polymorphic sites potential SNPs were filtered for intron-exon boundaries and visually inspected. We selected 1,536 candidate SNPs which were then used to design probes for validation by large-scale genotyping assays...

  17. Current knowledge on the photoneuroendocrine regulation of reproduction in temperate fish species.

    Science.gov (United States)

    Migaud, H; Davie, A; Taylor, J F

    2010-01-01

    Seasonality is an important adaptive trait in temperate fish species as it entrains or regulates most physiological events such as reproductive cycle, growth profile, locomotor activity and key life-stage transitions. Photoperiod is undoubtedly one of the most predictable environmental signals that can be used by most living organisms including fishes in temperate areas. This said, however, understanding of how such a simple signal can dictate the time of gonadal recruitment and spawning, for example, is a complex task. Over the past few decades, many scientists attempted to unravel the roots of photoperiodic signalling in teleosts by investigating the role of melatonin in reproduction, but without great success. In fact, the hormone melatonin is recognized as the biological time-keeping hormone in fishes mainly due to the fact that it reflects the seasonal variation in daylength across the whole animal kingdom rather than the existence of direct evidences of its role in the entrainment of reproduction in fishes. Recently, however, some new studies clearly suggested that melatonin interacts with the reproductive cascade at a number of key steps such as through the dopaminergic system in the brain or the synchronization of the final oocyte maturation in the gonad. Interestingly, in the past few years, additional pathways have become apparent in the search for a fish photoneuroendocrine system including the clock-gene network and kisspeptin signalling and although research on these topics are still in their infancy, it is moving at great pace. This review thus aims to bring together the current knowledge on the photic control of reproduction mainly focusing on seasonal temperate fish species and shape the current working hypotheses supported by recent findings obtained in teleosts or based on knowledge gathered in mammalian and avian species. Four of the main potential regulatory systems (light perception, melatonin, clock genes and kisspeptin) in fish reproduction

  18. Warming impacts on fish species composition in the Kattegat-Belt Sea

    DEFF Research Database (Denmark)

    Bryndum, Karoline Minna; MacKenzie, Brian

    Sea temperatures have been rising in the waters near Denmark during the past 1-2 decades and are expected to affect marine populations, species, communities and foodwebs. Here we investigate whether and how the species richness and composition of the marine fish community in the Kattegat and Belt...... Sea have been influenced by these changes. We hypothesize that the recent warming has led to an increase in species richness of the local community and that this increase is due to immigration of species from warmer areas. We use spring and fall survey data collected by DTU Aqua during the years 1994...

  19. Physiological and ecological factors influencing the radiocaesium contamination of fish species from Kiev reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Koulikov, A.O. [A.N. Severtzov Institute of Evolutionary Morphology and Ecology of Animals, Russian Academy of Sciences, Moscow (Russian Federation)

    1995-11-23

    The monitoring of {sup 137}Cs contamination of fish from the northern part of the Kiev reservoir between 1987 and 1992 indicated systematic differences in the long-term average contamination levels of different species, which are closely related to their trophic levels. The average contamination of the predatory species: perch (Perca fluviatilis) and pike (Esox lucius) were roughly factors of 6.3 and 4.4 respectively, higher than those of the nonpredatory species: bream (Abramis brama), silver bream (Blicca bjoerkna) and rudd (Scardinius erythrophothalmus). For tench (Tinca tinca) and goldfish (Carassius sp.), this factor is 2. The solution of the caesium balance equation in fish obtained for equilibrium conditions, which is applicable to the long-term contamination, provides some explanations for these accumulation differences between the species with respect to influences by different ecological and physiological factors.

  20. Length-weight relationships for six freshwater fish species in Iran

    Institute of Scientific and Technical Information of China (English)

    M. S. HEYDARNEJAD

    2009-01-01

    The aim of this study is to report the length-weight relationship parameters (a and b) for some economically important fish species from Iranian freshwaters. The length-weight relationships (LWR) are calculated for six freshwater fish species collected during 2006 and 2007 in Iran. The values of the exponent b in the LWR (W=aLb) vary between 2.985 and 3.543. The LWR with high correlation coefficient (r2) is significant for all the species. These parameters are of great importance to evaluate the relative condition of populations, biology, species management and their fisheries and stock assessment. The application of the length-weight relationships presented here should be limited to the observed length ranges.

  1. A new fish species of the subfamily Serraninae (Perciformes, Serranidae) from the Philippines.

    Science.gov (United States)

    Williams, Jeffrey T; Carpenter, Kent E

    2015-01-19

    A new species of serranine fish is described from the Philippine Islands. A single specimen of a new species, Chelidoperca santosi, captured by fishermen working in Palawan waters was discovered in the public fish market in Iloilo City, Panay, Philippines. Two additional specimens of the new species, also from the Philippines, were subsequently discovered in the collections of the Museum Victoria, Australia. The new species is currently known only from the Philippines and is characterized by its distinctive coloration with a row of four small dark spots on the snout (two in front of each eye) and two dark spots on the chin (one on each side of the symphysis of the dentaries), a white anal fin with six large yellow spots separated by broad white interspaces and a narrow yellow distal border, caudal fin with narrow yellow bars and a yellowish distal margin and no dark spots, and a combination of meristic and morphological characters. 

  2. Impacts of fishing low-trophic level species on marine ecosystems.

    Science.gov (United States)

    Smith, Anthony D M; Brown, Christopher J; Bulman, Catherine M; Fulton, Elizabeth A; Johnson, Penny; Kaplan, Isaac C; Lozano-Montes, Hector; Mackinson, Steven; Marzloff, Martin; Shannon, Lynne J; Shin, Yunne-Jai; Tam, Jorge

    2011-08-26

    Low-trophic level species account for more than 30% of global fisheries production and contribute substantially to global food security. We used a range of ecosystem models to explore the effects of fishing low-trophic level species on marine ecosystems, including marine mammals and seabirds, and on other commercially important species. In five well-studied ecosystems, we found that fishing these species at conventional maximum sustainable yield (MSY) levels can have large impacts on other parts of the ecosystem, particularly when they constitute a high proportion of the biomass in the ecosystem or are highly connected in the food web. Halving exploitation rates would result in much lower impacts on marine ecosystems while still achieving 80% of MSY.

  3. Classification accuracy of algorithms for blood chemistry data for three aquaculture-affected marine fish species.

    Science.gov (United States)

    Coz-Rakovac, R; Topic Popovic, N; Smuc, T; Strunjak-Perovic, I; Jadan, M

    2009-11-01

    The objective of this study was determination and discrimination of biochemical data among three aquaculture-affected marine fish species (sea bass, Dicentrarchus labrax; sea bream, Sparus aurata L., and mullet, Mugil spp.) based on machine-learning methods. The approach relying on machine-learning methods gives more usable classification solutions and provides better insight into the collected data. So far, these new methods have been applied to the problem of discrimination of blood chemistry data with respect to season and feed of a single species. This is the first time these classification algorithms have been used as a framework for rapid differentiation among three fish species. Among the machine-learning methods used, decision trees provided the clearest model, which correctly classified 210 samples or 85.71%, and incorrectly classified 35 samples or 14.29% and clearly identified three investigated species from their biochemical traits.

  4. Mercury Contamination in an Indicator Fish Species from Andean Amazonian Rivers Affected by Petroleum Extraction.

    Science.gov (United States)

    Webb, Jena; Coomes, Oliver T; Mainville, Nicolas; Mergler, Donna

    2015-09-01

    Elevated mercury (Hg) concentrations in fish from Amazonia have been associated with gold-mining, hydroelectric dams and deforestation but few studies consider the role of petroleum extraction. Hg levels were determined in fish samples collected in three river basins in Ecuador and Peru with contrasting petroleum exploitation and land-use characteristics. The non-migratory, piscivorous species, Hoplias malabaricus, was used as a bioindicator. The rate of Hg increase with body weight for this species was significantly higher on the Corrientes River, near the site of a recent oil spill, than on the other two rivers. In the absence of substantial deforestation and other anthropogenic sources in the Corrientes River basin, this finding suggests that oil contamination in Andean Amazonia may have a significant impact on Hg levels in fish.

  5. Patterns of energy allocation to reproduction in three Amazonian fish species

    Directory of Open Access Journals (Sweden)

    Rodrigo N. dos Santos

    Full Text Available The study considered the influence of the hydrological cycle and gonadal development on the accumulation and use of energy in three fish species from an Amazonian flooded area. Fishes were sampled over a 24 hour period at monthly intervals between July 2004 and June 2005 using gillnets of different mesh sizes. Body cavity fat and gonadosomatic indices were determined, as well as energy content of gonads and muscles. Amongst the studied species, different means of energy allocation for reproduction were found: Acestrorhynchus falcirostris allocate energy from body cavity fat to its gonads; Pygocentrus nattereri uses mainly energy accumulated in the muscles for the process of gonadal maturation; and Hoplosternum littorale uses energy accumulated in their muscles and body cavity fat for reproductive processes. It is quite clear that the flood pulse regulates the gain and use of the energy reserves in fishes from the Amazonian floodplain.

  6. Investigation of sensory profiles and hedonic drivers of emerging aquaculture fish species.

    Science.gov (United States)

    Alexi, Niki; Byrne, Derek V; Nanou, Evangelia; Grigorakis, Kriton

    2017-07-24

    The aquaculture sector needs to increase the diversity fish species and their processed products to cover rising consumer demands. Candidates for this diversification have been identified to be meagre, greater amberjack, pikeperch and wreckfish. Yet scientific knowledge on their sensory profiles and consumer hedonic responses is scarce. The aim of the current study was to investigate these aspects, since they are essential for product development and market targeting. Species exhibited different sensory profiles with the exception of the odor/flavor profiles of meagre and greater amberjack, which were similar. Texture was more important than odor/flavor in explaining interspecies differences. Yet the hedonic responses were equally related to texture and odor/flavor. None of the species received negative hedonic scores. Both positive and negative hedonic drivers were identified within the odor/flavor and texture modalities. The distinct profiles of meagre, greater amberjack, pikeperch and wreckfish make these fish species valuable first materials for new product development and for covering markets with different sensory preferences. Differences in fish texture are more easily perceivable, yet small variations in fish odor/flavor can have a great impact on consumers' hedonic responses. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  7. Record of the species of Tripartiella (Lom, 1959) from fishes of Manipur.

    Science.gov (United States)

    Mohilal, Naorem; Hemananda, Thounaojam

    2012-04-01

    Survey on Trichodinid ciliophorans from the fresh water fishes of Manipur revealed three known species of the genus Tripartiella from the gills of major carps Labeo rohita (Hamilton); Cirrhinus mrigala (Hamilton); Catla catla and Ciprinus carpio. These are redescribed in this communication.

  8. 77 FR 75896 - Atlantic Highly Migratory Species; 2013 Atlantic Shark Commercial Fishing Season

    Science.gov (United States)

    2012-12-26

    ... Species; 2013 Atlantic Shark Commercial Fishing Season AGENCY: National Marine Fisheries Service (NMFS... the Atlantic commercial shark fisheries (sandbar sharks, non-sandbar large coastal sharks, blue sharks, porbeagle sharks, and pelagic sharks (other than porbeagle and blue sharks), non-blacknose small...

  9. 77 FR 61562 - Atlantic Highly Migratory Species; 2013 Atlantic Shark Commercial Fishing Season

    Science.gov (United States)

    2012-10-10

    ... Species; 2013 Atlantic Shark Commercial Fishing Season AGENCY: National Marine Fisheries Service (NMFS... season for the Atlantic commercial shark fisheries. Quotas would be adjusted as allowable based on any over- and/or underharvests experienced during the 2011 and 2012 Atlantic commercial shark...

  10. 77 FR 24466 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2012-04-24

    ... Covered in This Notice The following listed species are covered in this notice: Chinook salmon... recovery plans and land- and fish-management decisions. The SBT would count and monitor adult spr/sum... conducted using boat electrofishing equipment, fyke nets, tangle nets, and pop-nets in the littoral zones...

  11. Divergent mating preferences and nuptial coloration in sibling species of cichlid fish

    NARCIS (Netherlands)

    Sluijs, Inke van der

    2008-01-01

    Mate choice by female cichlid fish from Lake Victoria plays an important role in speciation and the maintenance of species. Females are expected to select against males that are intermediate in their phenotype during the process of speciation driven by sexual selection. To test this, we hybridized

  12. Karyotype similarity between two sympatric Schizodon fish species (Anostomidae, Characiformes from the Paraguay River basin

    Directory of Open Access Journals (Sweden)

    Martins Cesar

    1998-01-01

    Full Text Available Fish of the neotropical family Anostomidae generally show low karyotype variability. Nevertheless, karyotype variants have been identified within some genera, providing information about their evolutionary history. Species of the genus Schizodon show a high degree of morphological and ecological similarity compared to other anostomids. In the present study, karyotype characteristics of Schizodon borelli (40 individuals and S. isognathum (one individual, two sympatric species found in the Paraguay River basin, were studied. C-banding, GC-specific fluorochrome Mitramycin (MM and Ag staining as well as in situ hybridization (FISH with rDNA probes were used. The karyotypes of these species were found to be very similar. Only two NORs were detected in a common chromosome pair of both species under Ag, MM and FISH treatments. Similar heterochromatin distribution patterns were also observed. A parallelism between the small karyotype variation and low morphological and ecological divergence observed for this genus is discussed. Their karyotype homogeneity might be related to populational features or, alternatively, might indicate that the maintenance of a symmetric and conserved karyotype structure represents optimal genomic organization among these fish.

  13. 78 FR 31518 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2013-05-24

    ... Anadromous Fish AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... Genetic Management Plans (HGMPs), pursuant to the Endangered Species Act of 1973, as amended (ESA). The... the draft environmental assessment should be sent to Brett Farman, National Marine Fisheries...

  14. Ocean warming, a rapid distributional shift, and the hybridization of a coastal fish species.

    Science.gov (United States)

    Potts, Warren M; Henriques, Romina; Santos, Carmen V; Munnik, Kate; Ansorge, Isabelle; Dufois, Francois; Booth, Anthony J; Kirchner, Carola; Sauer, Warwick H H; Shaw, Paul W

    2014-09-01

    Despite increasing awareness of large-scale climate-driven distribution shifts in the marine environment, no study has linked rapid ocean warming to a shift in distribution and consequent hybridization of a marine fish species. This study describes rapid warming (0.8 °C per decade) in the coastal waters of the Angola-Benguela Frontal Zone over the last three decades and a concomitant shift by a temperature sensitive coastal fish species (Argyrosomus coronus) southward from Angola into Namibia. In this context, rapid shifts in distribution across Economic Exclusive Zones will complicate the management of fishes, particularly when there is a lack of congruence in the fisheries policy between nations. Evidence for recent hybridization between A. coronus and a congener, A. inodorus, indicate that the rapid shift in distribution of A. coronus has placed adults of the two species in contact during their spawning events. Ocean warming may therefore revert established species isolation mechanisms and alter the evolutionary history of fishes. While the consequences of the hybridization on the production of the resource remain unclear, this will most likely introduce additional layers of complexity to their management.

  15. Divergent mating preferences and nuptial coloration in sibling species of cichlid fish

    NARCIS (Netherlands)

    Sluijs, Inke van der

    2008-01-01

    Mate choice by female cichlid fish from Lake Victoria plays an important role in speciation and the maintenance of species. Females are expected to select against males that are intermediate in their phenotype during the process of speciation driven by sexual selection. To test this, we hybridized t

  16. Divergent mating preferences and nuptial coloration in sibling species of cichlid fish

    NARCIS (Netherlands)

    Sluijs, Inke van der

    2008-01-01

    Mate choice by female cichlid fish from Lake Victoria plays an important role in speciation and the maintenance of species. Females are expected to select against males that are intermediate in their phenotype during the process of speciation driven by sexual selection. To test this, we hybridized t

  17. 77 FR 75611 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2012-12-21

    ..., and for a period following, dam removal when natural productivity conditions will be poor. The... levels are high and detrimental to natural-origin fish survival due to dam removal activities. The... intended to protect five species of salmon and steelhead (two of them ESA-listed) during the removal of...

  18. 78 FR 18963 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2013-03-28

    ... population segment of North American (SDPS) green sturgeon (Acipenser medirostris). ] Authority Scientific...-listed salmonid and non-listed fish species distribution, population abundance, habitat utilization, and... the effects of water diversion facilities maintained by the Turlock and Modesto Irrigation Districts...

  19. Food resources used by three species of fish in the semi-arid region of Brazil

    Directory of Open Access Journals (Sweden)

    Márcio J. da Silva

    Full Text Available Temporary and semi-permanent aquatic habitats in semi-arid Brazil have been reported as important sites supporting a diverse fish fauna. As such, they must be able to trophically sustain fish species that feed at different trophic levels. This study aims to describe the diets of Astyanax aff. bimaculatus, Hoplias malabaricus and Prochilodus brevis in aquatic systems in semi-arid Brazil, providing evidence of the importance of these habitats as supporters of large consumers like fish. The diet of the three species studied was diverse, feeding on a range of food items, from microalgae to fish. Despite that, a few items were more important to each of the study species. These results and the relatively high rates of stomach fullness indicate that a diverse and abundant food range is available in the study sites, but species seem to select some food resources. The present study provides evidence that despite being highly variable, intermittent and semi-permanent aquatic systems in semi-arid Brazil are able to trophically sustain large consumers.

  20. Unsaturated fish assemblages in rivers of the North-Western France : potential consequences for species introductions

    Directory of Open Access Journals (Sweden)

    BELKESSAM D.

    1997-01-01

    Full Text Available Introductions of freshwater fish into French rivers have been carried out with increasing frequency in the last decades. Thus, the potential impact of these introductions is of major concern for biologists and fishery managers. Knowledge of the degree of saturation of a community provides an important basis for understanding how the community reacts or will react to the introduction of new species. In this paper, we compare local and regional freshwater fish species richness in similar sizes tributaries and coastal rivers located in the same biogeographic region (North-Western France. We show 1 that species richness is greater for tributaries than for coastal rivers on both local (station and regional (catchment scales, and 2 that, whatever the rivers studied (tributaries or coastal rivers, there is a significant, positive linear relationship between local species richness and regional species richness. These findings suggest that local, and probably regional, freshwater fish communities in North-Western French rivers are unsaturated and thus, that major impacts on the community, such as short-term extinctions, are not to be expected. However, competition for food and space, predation, introduction of exotic parasites and diseases, could also affect some native species.

  1. Fish Species Observed in the Hawaiian Exclusive Economic Zone from the 1750s through 2003 (NODC Accession 0001486)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A list of Hawaiian fish species was created from contemporary and historical documents dating back to 1758. For each species, the name of the person who described...

  2. Fish Species Observed in the Hawaii Exclusive Economic Zone from the 1750s through 2003 (NODC Accession 0001486)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A list of Hawaiian fish species was created from contemporary and historical documents dating back to 1758. For each species, the name of the person who described...

  3. The future distribution of river fish: The complex interplay of climate and land use changes, species dispersal and movement barriers.

    Science.gov (United States)

    Radinger, Johannes; Essl, Franz; Hölker, Franz; Horký, Pavel; Slavík, Ondřej; Wolter, Christian

    2017-05-13

    The future distribution of river fishes will be jointly affected by climate and land use changes forcing species to move in space. However, little is known whether fish species will be able to keep pace with predicted climate and land use-driven habitat shifts, in particular in fragmented river networks. In this study, we coupled species distribution models (stepwise boosted regression trees) of 17 fish species with species-specific models of their dispersal (fish dispersal model FIDIMO) in the European River Elbe catchment. We quantified (i) the extent and direction (up- vs. downstream) of predicted habitat shifts under coupled "moderate" and "severe" climate and land use change scenarios for 2050, and (ii) the dispersal abilities of fishes to track predicted habitat shifts while explicitly considering movement barriers (e.g., weirs, dams). Our results revealed median net losses of suitable habitats of 24 and 94 river kilometers per species for the moderate and severe future scenarios, respectively. Predicted habitat gains and losses and the direction of habitat shifts were highly variable among species. Habitat gains were negatively related to fish body size, i.e., suitable habitats were projected to expand for smaller-bodied fishes and to contract for larger-bodied fishes. Moreover, habitats of lowland fish species were predicted to shift downstream, whereas those of headwater species showed upstream shifts. The dispersal model indicated that suitable habitats are likely to shift faster than species might disperse. In particular, smaller-bodied fish (species might substantially be restricted by movement barriers to respond to predicted climate and land use changes, while smaller-bodied species are rather restricted by their specific dispersal ability. © 2017 John Wiley & Sons Ltd.

  4. Genome analysis of seven species of Kengyilia (Triticeae: Poaceae) with FISH and GISH.

    Science.gov (United States)

    Dou, Quanwen; Wang, Richard R-C; Lei, Yuting; Yu, Feng; Li, Yuan; Wang, Haiqing; Chen, Zhiguo

    2013-11-01

    The genome compositions and genetic relationships of seven species of Kengyilia were assessed using a sequential fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH) technique. Five species, K. kokonorica, K. rigidula, K. hirsuta, K. grandiglumis, and K. thoroldiana, are native to Qinghai (China). The other two, K. alatavica and K. batalinii, are distributed in Xinjiang (China) and Kyrgyzstan, respectively. Each chromosome could be easily identified using chromosome markers (45S rDNA, 5S rDNA, pAs1, and AAG repeats) by FISH and allocated to the St, P, or Y genome by GISH. Molecular karyotype comparison indicated that K. alatavica and K. batalinii were distinct from the Qinghai species in all three genomes. These results support that the species of Kengyilia from Central Asia and the Qinghai-Tibetan plateau have independent origins. Genomic differentiation was still detected among the species of Kengyilia from Qinghai. Specifically, a common species-specific pericentric inversion was identified in both K. grandiglumis and K. thoroldiana, and an identical St-P non-Robertsonian translocation was frequently detected in K. hirsuta. The Qinghai species formed three genetic groups, K. kokonorica-K. rigidula, K. hirsuta, and K. grandiglumis-K. thoroldiana. The possible role of species-specific inversions and translocations in the evolution of StPY species is discussed.

  5. Risk-benefit evaluation of fish from Chinese markets: Nutrients and contaminants in 24 fish species from five big cities and related assessment for human health

    Energy Technology Data Exchange (ETDEWEB)

    Du, Zhen-Yu, E-mail: zdu@nifes.no [National Institute of Nutrition and Seafood Research (NIFES), N-5817 Bergen (Norway); Zhang, Jian [National Institute of Nutrition and Seafood Research (NIFES), N-5817 Bergen (Norway); Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing, 100050 (China); Department of Biomedicine, University of Bergen (Norway); Wang, Chunrong; Li, Lixiang; Man, Qingqing [Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing, 100050 (China); Lundebye, Anne-Katrine; Froyland, Livar [National Institute of Nutrition and Seafood Research (NIFES), N-5817 Bergen (Norway)

    2012-02-01

    The risks and benefits of fish from markets in Chinese cities have not previously been fully evaluated. In the present study, 24 common fish species with more than 400 individual samples were collected from markets from five big Chinese cities in 2007. The main nutrients and contaminants were measured and the risk-benefit was evaluated based on recommended nutrient intakes and risk level criteria set by relevant authorities. The comprehensive effects of nutrients and contaminants in marine oily fish were also evaluated using the data of two related human dietary intervention trials performed in dyslipidemic Chinese men and women in 2008 and 2010, respectively. The results showed that concentrations of contaminants analyzed including DDT, PCB{sub 7}, arsenic and cadmium were much lower than their corresponding maximum limits with the exception of the mercury concentration in common carp. Concentrations of POPs and n-3 LCPUFA, mainly EPA and DHA, were positively associated with the lipid content of the fish. With a daily intake of 80-100 g marine oily fish, the persistent organic pollutants in fish would not counteract the beneficial effects of n-3 LCPUFA in reducing cardiovascular disease (CVD) risk markers. Marine oily fish provided more effective protection against CVD than lean fish, particularly for the dyslipidemic populations. The risk-benefit assessment based on the present daily aquatic product intake in Chinese urban residents (44.9 and 62.3 g for the average values for all cities and big cities, respectively) indicated that fish, particularly marine oily fish, can be regularly consumed to achieve optimal nutritional benefits from n-3 LCPUFA, without causing significant contaminant-related health risks. However, the potential health threat from contaminants in fish should still be emphasized for the populations consuming large quantities of fish, particularly wild fish. - Highlights: Black-Right-Pointing-Pointer We collected 24 fish species with more than

  6. Turbidity interferes with foraging success of visual but not chemosensory predators

    Directory of Open Access Journals (Sweden)

    Jessica Lunt

    2015-09-01

    Full Text Available Predation can significantly affect prey populations and communities, but predator effects can be attenuated when abiotic conditions interfere with foraging activities. In estuarine communities, turbidity can affect species richness and abundance and is changing in many areas because of coastal development. Many fish species are less efficient foragers in turbid waters, and previous research revealed that in elevated turbidity, fish are less abundant whereas crabs and shrimp are more abundant. We hypothesized that turbidity altered predatory interactions in estuaries by interfering with visually-foraging predators and prey but not with organisms relying on chemoreception. We measured the effects of turbidity on the predation rates of two model predators: a visual predator (pinfish, Lagodon rhomboides and a chemosensory predator (blue crabs, Callinectes sapidus in clear and turbid water (0 and ∼100 nephelometric turbidity units. Feeding assays were conducted with two prey items, mud crabs (Panopeus spp. that rely heavily on chemoreception to detect predators, and brown shrimp (Farfantepenaus aztecus that use both chemical and visual cues for predator detection. Because turbidity reduced pinfish foraging on both mud crabs and shrimp, the changes in predation rates are likely driven by turbidity attenuating fish foraging ability and not by affecting prey vulnerability to fish consumers. Blue crab foraging was unaffected by turbidity, and blue crabs were able to successfully consume nearly all mud crab and shrimp prey. Turbidity can influence predator–prey interactions by reducing the feeding efficiency of visual predators, providing a competitive advantage to chemosensory predators, and altering top-down control in food webs.

  7. Human Health Risk from Metals in Fish from Saudi Arabia: Consumption Patterns for Some Species Exceed Allowable Limits

    KAUST Repository

    Burger, Joanna

    2014-10-06

    ABSTRACT: Fish are a healthful source of protein, but contaminants in some fish pose a risk. While there are multiple risk assessments from Europe and North America, there are far fewer for other parts of the world. We examined the risks from mercury, arsenic, lead, and other metals in fish consumed by people in Jeddah area, Saudi Arabia, using site-specific data on consumption patterns and metal levels in fish. The U.S. Environmental Protection Agency\\'s Hazard Quotient (HQ) and cumulative Hazard Index (HI) for non-cancer endpoints and Carcinogenic Index for cancer were used to determine the health risk based on fish consumption rates. Of the 13 fish species examined, HQ was greater than 1 (indicating elevated risk) in two species for arsenic, and seven species for methylmercury. The cumulative HI for all metals was above 1 for all but three species of fish at the mean consumption rates. Generally, fish species with HI above 1 for one sampling location, had HI above 1 for all sampling locations. The implications of these findings are discussed in the light of strategies for reducing risk from fish consumption while encouraging dietary intakes of fish with low mercury and arsenic levels.

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

    Science.gov (United States)

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

    2013-11-01

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

  9. 50 CFR 222.309 - Permits for listed species of sea turtles involving the Fish and Wildlife Service.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Permits for listed species of sea turtles involving the Fish and Wildlife Service. 222.309 Section 222.309 Wildlife and Fisheries NATIONAL MARINE... species of sea turtles involving the Fish and Wildlife Service. (a) This section establishes...

  10. Condition factor in nine species of fish of the Characidae family in the upper Paraná River floodplain, Brazil

    Directory of Open Access Journals (Sweden)

    LIZAMA M. DE LOS A. P.

    2002-01-01

    Full Text Available The condition factor for nine species of tropical freshwater fish of the Characidae family in the upper Paraná River floodplain is described. Fish were caught over a period of 12 months (February 1993 to March 1994. Knowledge of the nine species is important for adequate management and maintenance of the biological equilibrium of the ecosystem.

  11. Diel variation in feeding and vertical distribution of ten co- occurring fish species: consequences for resource partitioning

    NARCIS (Netherlands)

    Piet, G.J.; Guruge, W.A.H.P.

    1997-01-01

    The diel variations in feeding behaviour and vertical distribution were determined for ten species of a tropical fish community in a shallow SE Sri Lankan reservoir. The fish community consisted of two introduced exotic tilapias and eight indigenous riverine species including five cyprinids, one cla

  12. Occurrence and Intensity of Anisakid Nematode Larvae in Some Commercially Important Fish Species in Persian Gulf

    Directory of Open Access Journals (Sweden)

    Maryam DADAR

    2016-10-01

    Full Text Available Background: Anisakid nematodes are common parasites of fish, mammals, fish-eating birds, and reptiles with a worldwide distribution, causing diseases in human, fish and important economic losses.Methods: A preliminary epidemiological study was carried out on Anisakid nematodes larvae in some commercially important fish species to evaluate the anisakid nematode larvae from greater lizardfish, (Saurida tumbil, Japanese thread fin bream (Nemipterus japonicus, crocodile longtom (Tylosurus crocodilus crocodiles and longfin trevally (Carangoides armatus from the Persian Gulf of Iran.Result: The collected larvae were identified mainly as the third larval stage (L3 of Hysterothylacium larval type A, B and C, Anisakis sp., Raphidascaris sp., Pseudoterranova sp. and Philometra sp. (Nematoda: Philometridae. The prevalence of Anisakid larvae infection of examined fishes was 97.2% in N. japonicus, 90.3% in S. tumbil, 20.5% in crocodile longtom and 5.5% in longfin trevally. Anisakis type III for the first time was different from Anisakis type I and Anisakis type II.Discussion: Zoonotic anisakids by high prevalence in edible fish could be a health hazard for people. So health practices should be considered in these areas.

  13. Nutritional evaluation of commercially important fish species of Lakshadweep archipelago, India.

    Directory of Open Access Journals (Sweden)

    Kottila Veettil Dhaneesh

    Full Text Available Estimation of nutrition profile of edible fishes is essential and thus a bio-monitoring study was carried out to find out the nutritional composition of commonly available fishes in Agatti Island water of Lakshadweep Sea. Protein, carbohydrate, lipid, ash, vitamin, amino acid and fatty acid composition in the muscle of ten edible fish species were studied. Proximate analysis revealed that the protein, carbohydrate, lipid and ash contents were high in Thunnus albacares (13.69%, Parupeneus bifasciatus (6.12%, Hyporhamphus dussumieri (6.97% and T. albacares (1.65%, respectively. Major amino acids were lysine, leucine and methionine, registering 2.84-4.56%, 2.67-4.18% and 2.64-3.91%, respectively. Fatty acid compositions ranged from 31.63% to 38.97% saturated (SFA, 21.99-26.30% monounsaturated (MUFAs, 30.32-35.11% polyunsaturated acids (PUFAs and 2.86-7.79% branched fatty acids of the total fatty acids. The ω-3 and ω-6 PUFAs were ranged 13.05-21.14% and 6.88-9.82% of the total fatty acids, respectively. Hence, the fishes of Lakshadweep Sea are highly recommended for consumption, since these fishes are highly enriched with nutrition. The results can be used as a baseline data for comparing the various nutritional profiles of fishes in future.

  14. Light climate and dissolved organic carbon concentration influence species-specific changes in fish zooplanktivory

    Science.gov (United States)

    Weidel, Brian C.; Baglini, Katherine; Jones, Stuart E.; Kelly, Patrick T.; Solomon, Christopher T.; Zwart, Jacob A.

    2017-01-01

    Dissolved organic carbon (DOC) in lakes reduces light penetration and limits fish production in low nutrient lakes, reportedly via reduced primary and secondary production. Alternatively, DOC and light reductions could influence fish by altering their visual feeding. Previous studies report mixed effects of DOC on feeding rates of zooplanktivorous fish, but most investigators tested effects of a single concentration of DOC against clear-water, turbid, or algal treatments. We used a controlled laboratory study to quantify the effects of a DOC gradient (3–19 mg L−1) on average light climate and the zooplankton feeding rate of 3 common, north temperate fishes. Light availability, which was inversely related to DOC concentration, had a positive and linear effect on zooplankton consumption by juvenile largemouth bass (Micropterus salmoides) and bluegill (Lepomis macrochirus), explaining 22% and 28% of the variation in consumption, respectively. By contrast, zooplankton feeding rates by fathead minnow (Pimephales promelas) were best predicted by a nonlinear, negative influence of light (R2 = 0.13). In bluegill feeding trials we found a general trend for positive selection of larger zooplankton (Cladocera and Chaoboridae); however, the light climate did not influence the selection of prey type. Largemouth bass selected for larger-bodied zooplankton, with weak evidence that selectivity for large Cladocera changed from negative to neutral selection based on electivity values across the light gradient. Our results suggest that the effect of DOC on the light climate of lakes may directly influence fish zooplanktivory and that this influence may vary among fish species.

  15. Impact of genetically improved fish species and technology on selected hatchery and fish production in Bangladesh

    Directory of Open Access Journals (Sweden)

    MS Islam

    2017-06-01

    Full Text Available The study was carried out in IAPP commanding areas from July to September 2015. A total of 8 hatchery and 240 farmers were selected for this study from Rangpur and Barisal region. About 153% Tilapia production increased which was from 34 to 86 lakh, which was 148% in Rangpur district. Thai koi production was increased about 320% in Rangpur and it was 152% in Barisal. It was observed that, per hatchery Tilapia profit was Tk. 17.35 lakh and Tk. 17.18 lakh in Rangpur and Barisal, respectively. While, total profit was 3.9 times more for Thai koi in Rangpur and it was about 1.7 times more in Barisal after IAPP-BFRI project implementation. Impact of improved germplasm on grow out system was estimated. Finding shows that before IAPP-BFRI project the average harvesting weight of tilapia fish was 122g but after using IAPP-BFRI germplasm, it increased to 194g in Rangpur district. In case of Thai Koi, the harvesting weight gain was 26% in Rangpur district and it was statistically significant at 1% level. Survey results also show that per acre profit was only Tk.86671 for Tilapia farming before IAPP whereas it was increased to Tk. 234853 after IAPP-BFRI intervention. At the same time, profit from Thai Koi was increased about 189% after IAPPBFRI activities. Similarly, profit was increased about 86% in case of Pangus farming and this positive impact was statistically significant at 1% level. Therefore, it may conclude that, farmers can significantly increase Tilapia, Thai Koi and Pangus production as well as can maximize profit using IAPP technology.

  16. 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

  17. Composition of fish species in the Bering and Chukchi Seas and their responses to changes in the ecological environment

    Institute of Scientific and Technical Information of China (English)

    LIN Longshan; CHEN Yongjun; LIAO Yunchih; ZHANG Jing; SONG Puqing; YU Xingguang; WU Risheng; SHAO Kwang-tsao

    2014-01-01

    Based on trawl surveys in the Bering Sea and Chukchi Sea during the 2010 Chinese National Arctic Research Expedition, fish biodiversity characteristics, such as fish composition, dominant species, biodiversity, and faunal characteristics were conducted. We also discussed the responses of fishes to the quick changes in Arctic climate. The results showed that a total of 41 species in 14 families were recorded in these waters. The dominant species were Hippoglossoides robustus, Boreogadus saida, Myoxocephalus scorpius, Lumpenus fa-bricii, and Artediellus scaber. There were 35 coldwater species, accounting for 85.37%, and six cold temperate species, occupying 14.63%. The habitat types of fish could be grouped as follows:35 species of demersal fish-es, five benthopelagic fishes, and one pelagic fish. The Shannon-Wiener diversity index (H′) (range between 0 and 2.18, 1.21 on average) was not high, and descended from south to north. Climate change has caused some fishes to shift along their latitudinal and longitudinal distribution around the Arctic and Subarctic areas, and this could lead to the decline of Arctic fishery resources.

  18. Effects of species diversity on functional trait of legume forage%物种多样性对豆科牧草功能特征的影响

    Institute of Scientific and Technical Information of China (English)

    张灵菲; 魏斌; 郝敏; 葛庆征; 傅华; 张卫国; 江小雷

    2012-01-01

    利用室外盆栽实验方法就物种多样性对豆科牧草功能特征及生产力的影响进行了研究。结果表明,物种多样性对豆科牧草比叶面积、株高有促进作用,二者呈显著正相关关系;对相对生长率、根深、叶干物质含量和单位叶面积根量4个功能特征有负面影响,4个变量均随物种多样性的增加而显著下降(P〈0.05)。豆科牧草的地上、地下生产力都随着物种多样性的增加而下降。研究结果说明。随着物种多样性的增加,种间竞争作用导致豆科牧草的比叶面积和株高增加,而导致相对生长率、根深、叶干物质含量和单位叶面积根量4个与生产力密切相关的功能特征值减小,进而限制混播群落中豆科牧草的生产力。%A pot experiment was used to determine the effects of species diversity on functional traits of legume forages by measuring the relative growth rate, specific leaf area, leaf dry mass content, plant height, root depth and root mass per unit leaf area, and productivity. The results of this study indicated that the species diversity had a positive effect on specific leaf area and plant height, and a negative effect on relative growth rate, root depth, leaf dry mass content, and root mass per unit leaf area. The productivity, aboveground and belowground biomass of legume forage decreased as the species diversity increased. These results suggested that the increasing interspecific competition caused by the increase of species diversity increased the specific leaf area and plant height, but restricted other four functional traits and the productivity of legume forages.

  19. Population and biological parameters of selected fish species from the middle Xingu River, Amazon Basin.

    Science.gov (United States)

    Camargo, M; Giarrizzo, T; Isaac, V J

    2015-08-01

    This study estimates the main biological parameters, including growth rates, asymptotic length, mortality, consumption by biomass, biological yield, and biomass, for the most abundant fish species found on the middle Xingu River, prior to the construction of the Belo Monte Dam. The specimens collected in experimental catches were analysed with empirical equations and length-based FISAT methods. For the 63 fish species studied, high growth rates (K) and high natural mortality (M) were related to early sexual maturation and low longevity. The predominance of species with short life cycles and a reduced number of age classes, determines high rates of stock turnover, which indicates high productivity for fisheries, and a low risk of overfishing.

  20. Toxic Metals in Pelagic, Benthic and Demersal Fish Species from Mediterranean FAO Zone 37.

    Science.gov (United States)

    Naccari, Clara; Cicero, Nicola; Ferrantelli, Vincenzo; Giangrosso, Giuseppe; Vella, Antonio; Macaluso, Andrea; Naccari, Francesco; Dugo, Giacomo

    2015-11-01

    Fish represents a nutrient-rich food but, at the same time, is one of the most important contributor to the dietary intake of heavy metals. The aim of this study was to assess residual levels of Pb, Cd and Hg in different species, caught from FAO zones 37 1.3 and 37 2.2, particularly small pelagic, benthic and demersal fishes. The results obtained showed the absence of toxic metal in fishes from FAO zone 37 1.3. Relating to FAO zone 37 2.2, instead, in all samples we observed the absence of Pb, small concentrations of Cd (0.081±0.022 mg/kg) and higher Hg residual levels (0.252±0.033 mg/kg). Particularly, the trend of Cd contamination was similar in all species whereas Hg showed high levels in demersal, intermediate in pelagic and low in benthic species. However, only Cd concentrations exceed the MRL in mackerel, mullet, sea-bream fishes, according to Regulation CE n. 629/2008 and n. 488/2014.

  1. Assessment of trace metals in fish species of urban rivers in Bangladesh and health implications.

    Science.gov (United States)

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

    2015-01-01

    Levels of six metals i.e. chromium (Cr), nickel (Ni), copper (Cu), arsenic (As), cadmium (Cd) and lead (Pb) in three fish species (Channa punctatus, Heteropneustes fossilis and Trichogaster fasciata) from three urban rivers in Bangladesh were measured. Concentrations of Cr, Ni, Cu, As, Cd and Pb in fish species were 0.75-4.8, 0.14-3.1, 1.1-7.2, 0.091-0.53, 0.007-0.13, and 0.052-2.7mg/kg ww, respectively. The analyzed metals were significantly different between species and seasons (p<0.05). The target hazard quotients (THQs) and carcinogenic risk (CR) for individual metal showed that As and Pb in muscle was particularly hazardous and potential risk for the low, medium and high fish consumer in Bangladesh. Some of the trace metals' concentrations are higher than the recommended value, which suggest that the water and fish of these rivers are not completely safe for human health.

  2. Biomarker sensitivity for polynuclear and halogenated aromatic hydrocarbon contamination in fish species from Galveston Bay

    Energy Technology Data Exchange (ETDEWEB)

    Willett, K.; McDonald, S.; Steinberg, M.; Beatty, K.; Safe, S. [Texas A and M Univ., College Station, TX (United States)

    1995-12-31

    The Galveston Bay estuary exhibits a contamination gradient for polynuclear aromatic hydrocarbons (PAHs) and halogenated aromatic hydrocarbons, which is useful for comparing biomarker response sensitivity in fish taken from different bay locations. Two fish species, hardhead catfish (Arius felis) and Atlantic croaker (Micropogon undulatus), were collected from four stations where sediment total PAHs ranged from 68 to > 1,000 ng/g. Hardhead catfish showed no consistent CYP1A mediated responses (hepatic ethoxyresorufin-O-deethylase activity (EROD), CYP1A mRNA levels, or CYP1A immunoreactive protein) in the field collected fish or in fish dosed with up to 15 mg/kg benzo(a)pyrene (BaP). Significant differences were seen in field collected hardhead catfish in biliary concentrations of naphthalene, phenanthrene, and BaP metabolites. Conversely, in croakers taken from the same four Galveston Bay locations, there were significant elevations IN EROD and glutathione-S-transferase activities, CYP1A immunoreactive protein, and biliary PAH metabolites at the contaminated stations. These studies suggest that croaker is a good monitoring species especially with respect to induction of CYP1A mediated responses by PAHs. Biliary PAH metabolites and PAH-DNA adducts were sensitive to PAH contamination in both species.

  3. Cadmium and lead in selected tissues of two commercially important fish species from the Adriatic Sea.

    Science.gov (United States)

    Gaspić, Z Kljaković; Zvonarić, T; Vrgoc, N; Odzak, N; Barić, A

    2002-12-01

    Baseline levels of cadmium and lead were determined in muscle tissue and liver of hake (Merluccius merluccius) and red mullet (Mullus barbatus), two commercially important fish species from the eastern Adriatic. Concentrations of trace metals in liver (Cd: 6-183 microg kg(-1) w. wt. ; Pb: 39-970 microg kg(-1) w. wt.) were within the range of recently published data for the Mediterranean. In the muscle tissue, cadmium concentrations (4.1-29 microg kg(-1) w. wt.) were among the lowest reported values for the Mediterranean, whereas lead levels (49-158 microg kg(-1) w. wt.) were within the range of values reported for various coastal areas of the Mediterranean. Presented data on cadmium and lead content in the studied fish species provide no proof of the general pollution of the Adriatic. Obtained data were tested in relation to fish length. Metal concentrations in liver decreased with the increase in fish size, whereas no significant correlation was found between trace metal levels in the muscle tissue and the length of both species. Relationships between metal concentrations and sex were also tested, but they gave no significant results. A comparison of contaminant concentrations in the edible tissue of hake and red mullet with the Croatian legislation shows that the consumption of their meat is not harmful for humans, not even for the most endangered population from the coastal region.

  4. Note on the distribution of ectopic thyroid tissue in five species of poeciliid fishes

    Energy Technology Data Exchange (ETDEWEB)

    Woodhead, A.D.; Bryant, P.C.

    1982-01-01

    The intraperitoneal injection of polycylic aromatic hydrocarbons in young Amazon mollies induces proliferation of ectopic thyroid tissue in the spleen. The authors have surveyed untreated mollies, Poecilia formosa, and four closely related poeciliid fishes to see if ectopic thyroid tissue occurs normally in the spleen. If this were the case, it is possible that the tissue may have been stimulated to proliferate by the injected compounds. We found no instances of ectopic thyroid at any site in 50 untreated Amazon mollies examined nor in some 50 spleens dissected from other untreated fish. Splenic thyroid tissue was found in five guppies from 50 surveyed, but did not occur in other species.

  5. Mapping spatial variation in demersal fish species diversity and composition in the North Sea: accounting for species- and size-related catchability in survey trawls

    NARCIS (Netherlands)

    Fraser, H.M.; Greenstreet, S.P.R.; Fryer, R.J.; Piet, G.J.

    2008-01-01

    The paper maps spatial patterns of groundfish species diversity. It considers how the catchability of different fish species in two different types of bottom trawls, the IBTS GOV and the 8-m beam trawl, influences the estimates of species diversity. Maps of groundfish species diversity derived from

  6. Optimising invasive fish management in the context of invasive species legislation in South Africa

    Directory of Open Access Journals (Sweden)

    Darragh J. Woodford

    2017-03-01

    Full Text Available Background: South Africa hosts a large number of non-native freshwater fishes that were introduced for various industries. Many of these species are now listed under the National Environmental Management: Biodiversity Act (NEM:BA Alien and Invasive Species (A&IS lists and regulations, though the practical options available to conservation agencies to effectively manage these fishes vary greatly among species and regions. Objectives & methods: We assessed the history and status of national legislation pertaining to invasive freshwater fishes, and the practical implications of the legislation for managing different species with contrasting distributions, impacts and utilisation value. Results: The smallmouth bass, despite being a potential conflict-generating species, is fairly straightforward to manage based on current legislation. Two species of trout, which remain absent from the NEM:BA A&IS lists because of ongoing consultation with stakeholders, continue to be managed in regions like the Western Cape province using existing provincial legislation. To maximise the limited capacity for management within conservation agencies, we proposed a decision-support tool that prioritises invasive fish populations that represent high environmental risk and low potential for conflict with stakeholders. Using three case studies, we demonstrated how the tool can be used to set management goals of ‘eradicate’, ‘manage against impacts and further spread’ and ‘continue to monitor population’ as the most pragmatic solutions given the state of an invasion, its socio-economic impact and the capacity of the responsible agency to act. Conclusion: By choosing a pragmatic management strategy, conservation agencies can maximise the effective deployment of limited resources, while minimising avoidable conflicts with stakeholders.

  7. Global and Regional Patterns in Riverine Fish Species Richness: A Review

    Directory of Open Access Journals (Sweden)

    Thierry Oberdorff

    2011-01-01

    Full Text Available We integrate the respective role of global and regional factors driving riverine fish species richness patterns, to develop a synthetic model of potential mechanisms and processes generating these patterns. This framework allows species richness to be broken down into different components specific to each spatial extent and to establish links between these components and the processes involved. This framework should help to answer the questions that are currently being asked by society, including the effects of species invasions, habitat loss, or fragmentation and climate change on freshwater biodiversity.

  8. Evaluation of Trace Metal Levels in Tissues of Two Commercial Fish Species in Kapar and Mersing Coastal Waters, Peninsular Malaysia

    Directory of Open Access Journals (Sweden)

    Fathi Alhashmi Bashir

    2012-01-01

    Full Text Available This study is focused on evaluating the trace metal levels in water and tissues of two commercial fish species Arius thalassinus and Pennahia anea that were collected from Kapar and Mersing coastal waters. The concentrations of Fe, Zn, Al, As, Cd and Pb in these coastal waters and muscle, liver and gills tissues of the fishes were quantified. The relationship among the metal concentrations and the height and weight of the two species were also examined. Generally, the iron has the highest concentrations in both water and the fish species. However, Cd in both coastal waters showed high levels exceeding the international standards. The metal level concentration in the sample fishes are in the descending order livers > gills > muscles. A positive association between the trace metal concentrations and weight and length of the sample fishes was investigated. Fortunately the level of these metal concentrations in fish has not exceeded the permitted level of Malaysian and international standards.

  9. A new simplex approach to highlight multi-scale feeding behaviors in forager species from stomach contents: application to insectivore lizard population.

    Science.gov (United States)

    Semmar, Nabil; Roux, Maurice

    2014-04-01

    Stomach contents represent complex mixture systems which depend on feeding mode and level of forager species (carnivores, herbivores) as well as on natural availability/distribution of food resources (preys, plants). Such mixture systems can be considered as small black boxes condensing wide ecological information on (i) feeding behaviors of predator (or herbivore) and (ii) local diversity of preys (or host plants). Feeding behaviors of a hunter species toward different prey taxa show a complex variability whose investigation requires multivariate statistical tools. This paper presents a new computational approach which statistically analyzes stomach contents' variability in a predator population to graphically highlight different feeding behaviors. It is a simulation approach iteratively combining the variability of different diet patterns by using a simplex mixture design. Average combinatorial results are graphically visualized to highlight scale-dependent relationships between consumption rates of different food types found in the stomachs. The simplex approach was applied on different subpopulations of Phrynosoma douglassi brevirostre, an insectivore lizard species. These subpopulations were initially defined by different criteria including statistical clusters, gender and sampling periods. Results highlighted successive trade-offs over months of captured potential preys switching from small and less mobile preys to large and flying ones. In these dietary transitions, P. douglassi manifested a systematic memorization of previous preys and a gradual foraging learning of the next ones. These results highlighted lightness on dietary flexibility helping this specialist predator to switch between diets based on different potential preys. Adult male and adult female lizards showed different feeding behaviors due to some predation lag-time between them and different dietary ratios toward the same considered preys.

  10. Integrative taxonomy detects cryptic and overlooked fish species in a neotropical river basin.

    Science.gov (United States)

    Gomes, Laís Carvalho; Pessali, Tiago Casarim; Sales, Naiara Guimarães; Pompeu, Paulo Santos; Carvalho, Daniel Cardoso

    2015-10-01

    The great freshwater fish diversity found in the neotropical region makes management and conservation actions challenging. Due to shortage of taxonomists and insufficient infrastructure to deal with such great biodiversity (i.e. taxonomic impediment), proposed remedies to accelerate species identification and descriptions include techniques that combine DNA-based identification and concise morphological description. The building of a DNA barcode reference database correlating meristic and genetic data was developed for 75 % of the Mucuri River basin's freshwater fish. We obtained a total of 141 DNA barcode sequences from 37 species belonging to 30 genera, 19 families, and 5 orders. Genetic distances within species, genera, and families were 0.74, 9.5, and 18.86 %, respectively. All species could be clearly identified by the DNA barcodes. Divergences between meristic morphological characteristics and DNA barcodes revealed two cryptic species among the Cyphocharax gilbert and Astyanax gr. bimaculatus specimens, and helped to identify two overlooked species within the Gymnotus and Astyanax taxa. Therefore, using a simplified model of neotropical biodiversity, we tested the efficiency of an integrative taxonomy approach for species discovery, identification of cryptic diversity, and accelerating biodiversity descriptions.

  11. Meta-analysis of carrying capacity and abundance-area relationships in marine fish species

    DEFF Research Database (Denmark)

    Mantzouni, Irene

    fish produced by spawners in a given year which subsequently grow and survive to become vulnerable to fishing gear) have reacted to temperature fluctuations, and in particular to extremes of temperature, throughout the north Atlantic. Meta-analytical methods based on effect sizes were employed......Knowledge on the carrying capacity and the abundance-area relationships of fish is critical to evaluate the impacts of exploitation and climate on the sustainability and also the recovery potential of the populations. Of particular interest is climate change, inducing major consequences...... for population dynamics and life histories of marine biota as it progresses in the 21st century. In the present PhD project, a variety of meta-analytic methods was employed to statistically combine data across the north Atlantic distributions of 3 commercially and ecologically important species; cod (Gadus...

  12. Small Fish Species as Powerful Model Systems to Study Vertebrate Physiology in Space

    Science.gov (United States)

    Muller, M.; Aceto, J.; Dalcq, J.; Alestrom, P.; Nourizadeh-Lillabadi, R.; Goerlich, R.; Schiller, V.; Winkler, C.; Renn, J.; Eberius, M.; Slenzka, K.

    2008-06-01

    Small fish models, mainly zebrafish (Danio rerio) and medaka (Oryzias latipes), have been used for many years as powerful model systems for vertebrate developmental biology. Moreover, these species are increasingly recognized as valuable systems to study vertebrate physiology, pathology, pharmacology and toxicology, including in particular bone physiology. The biology of small fishes presents many advantages, such as transparency of the embryos, external and rapid development, small size and easy reproduction. Further characteristics are particularly useful for space research or for large scale screening approaches. Finally, many technologies for easily characterizing bones are available. Our objective is to investigate the changes induced by microgravity in small fish. By combining whole genome analysis (microarray, DNA methylation, chromatin modification) with live imaging of selected genes in transgenic animals, a comprehensive and integrated characterization of physiological changes in space could be gained, especially concerning bone physiology.

  13. Intra-seasonal variation in foraging behavior among Adélie penguins (Pygocelis adeliae) breeding at Cape Hallett, Ross Sea, Antarctica

    Science.gov (United States)

    Lyver, P.O.B.; MacLeod, C.J.; Ballard, G.; Karl, B.J.; Barton, K.J.; Adams, J.; Ainley, D.G.; Wilson, P.R.

    2011-01-01

    We investigated intra-seasonal variation in foraging behavior of chick-rearing Adélie penguins, Pygoscelis adeliae, during two consecutive summers at Cape Hallett, northwestern Ross Sea. Although foraging behavior of this species has been extensively studied throughout the broad continental shelf region of the Ross Sea, this is the first study to report foraging behaviors and habitat affiliations among birds occupying continental slope waters. Continental slope habitat supports the greatest abundances of this species throughout its range, but we lack information about how intra-specific competition for prey might affect foraging and at-sea distribution and how these attributes compare with previous Ross Sea studies. Foraging trips increased in both distance and duration as breeding advanced from guard to crèche stage, but foraging dive depth, dive rates, and vertical dive distances travelled per hour decreased. Consistent with previous studies within slope habitats elsewhere in Antarctic waters, Antarctic krill (Euphausia superba) dominated chick meal composition, but fish increased four-fold from guard to crèche stages. Foraging-, focal-, and core areas all doubled during the crèche stage as individuals shifted distribution in a southeasterly direction away from the coast while simultaneously becoming more widely dispersed (i.e., less spatial overlap among individuals). Intra-specific competition for prey among Adélie penguins appears to influence foraging behavior of this species, even in food webs dominated by Antarctic krill.

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

    Science.gov (United States)

    Salzburger, Walter; Meyer, Axel

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

  15. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (south Florida)

    Energy Technology Data Exchange (ETDEWEB)

    Jory, D.E.; Iversen, E.S. (Miami Univ., FL (USA). Rosenstiel School of Marine and Atmospheric Sciences)

    1989-08-01

    Black, red, and Nassau groupers (Mycteroperca bonaci, Epinephelus morio, and E. striatus, respectively) are widely distributed on rocky bottoms and reefs along the south Florida coast. They are the most valuable marine finfish group in Florida, comprising about 25% of the total value of landings in 1984. The three species can be distinguished by morphometric, meristic, and body color characteristics. Younger fish are typically found in shallow, inshore grass beds, and larger, older fish are generally restricted to deep waters. The three species are protogynous hermaphrodites. Sexual transition can occur at any length over about 300 mm SL. An offshore movement apparently coincides with the onset of sexual maturity. Spawning aggregations have been observed throughout the year, but occur mostly between late spring and early summer. Fecundity estimates range from about 800,000 to 5,000,000 eggs per female. Both the eggs and the larvae are planktonic. Their early life history is poorly known. Larvae probably leave the plankton and become benthic at around 20--30 mm SL. Growth rates range from about 2 to 10 mm/month. The three species are unspecialized carnivores, feeding on a variety of fishes, crustaceans, and mollusks. Interspecific competition for food and shelter may be common because of the overlap in distribution, habitat, size, and food habitats. For the three species, a number of predators and parasites have been reported. Both the black and red groupers have been implicated in ciguatera poisonings in south Florida. 70 refs., 3 figs., 3 tabs.

  16. Steroid Content of Some Species of Deep Sea Fish in Western Sumatra and Southern Java Ocean

    Directory of Open Access Journals (Sweden)

    Sugeng Heri Suseno

    2013-11-01

    Full Text Available In this research, some researchers suspect steroid hormone content on Bathypteorois and Erimoensis species of Bajacalifornia atricolor. The purpose of this research is to know steroid content. This research used the 11 species of marine fish in the Western ocean obtained in Southern Sumatra and Java through research vessel Baruna Jaya IV, in September and October 2004. The species are Alepocephalus bicolor, Antigonia rubescens, Barbourisia rufa, Bajacalifornia eromoensis, Caelorinchus divergens, Polymixiasp, Rouleina guentheri, Setarches guentheri, Synagrops japonicus, Tydermania dalgleishi, Xenolepidichthys. From the results of proximate analysis, the nutrient content in some marine fish are 11.94-20.81% protein contents, 0.01-4.84% fat contents, 73.29-82.73% moisture contents and 1.07-2.49% ash content. On analysis of HPLC (High Performance Liquid Chromatography the fat contents of steroid obtained are between 0026-0.016%. Deep sea fish species that assumed have steroids compounds are Bajacalifornia eriomoensis, Caelorinchus divergens, Tydermania navigatoris, Roulenia guentheri, Antigonia rubencens, Alepocephalus bicolor, Synagrops japonicus, Bajacalifornia erimoensis showed the best results on HPLC test so it continued with infrared test to show the similarity of steroid group.

  17. Ecological conversion efficiency and its influencers in twelve species of fish in the Yellow Sea Ecosystem

    Science.gov (United States)

    Tang, Qisheng; Guo, Xuewu; Sun, Yao; Zhang, Bo

    2007-09-01

    The ecological conversion efficiencies in twelve species of fish in the Yellow Sea Ecosystem, i.e., anchovy ( Engraulis japonicus), rednose anchovy ( Thrissa kammalensis), chub mackerel ( Scomber japonicus), halfbeak ( Hyporhamphus sajori), gizzard shad ( Konosirus punctatus), sand lance ( Ammodytes personatus), red seabream ( Pagrus major), black porgy ( Acanthopagrus schlegeli), black rockfish ( Sebastes schlegeli), finespot goby ( Chaeturichthys stigmatias), tiger puffer ( Takifugu rubripes), and fat greenling ( Hexagrammos otakii), were estimated through experiments conducted either in situ or in a laboratory. The ecological conversion efficiencies were significantly different among these species. As indicated, the food conversion efficiencies and the energy conversion efficiencies varied from 12.9% to 42.1% and from 12.7% to 43.0%, respectively. Water temperature and ration level are the main factors influencing the ecological conversion efficiencies of marine fish. The higher conversion efficiency of a given species in a natural ecosystem is acquired only under the moderate environment conditions. A negative relationship between ecological conversion efficiency and trophic level among ten species was observed. Such a relationship indicates that the ecological efficiency in the upper trophic levels would increase after fishing down marine food web in the Yellow Sea ecosystem.

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

    Science.gov (United States)

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

    2010-03-01

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

  19. Susceptibility of Japanese Cyprininae fish species to cyprinid herpesvirus 2 (CyHV-2).

    Science.gov (United States)

    Ito, Takafumi; Maeno, Yukio

    2014-03-14

    Cyprinid herpesvirus 2 (CyHV-2) is known as the causative agent of herpesviral haematopoietic necrosis (HVHN) of goldfish (Carassius auratus). Recently, the virus has also been detected from Prussian carp (C. gibelio) and crucian carp (C. carassius) from European and Asian countries. To analyze the risk of spreading to new host species, the susceptibility of other fish species to the virus is essential. In this study experimental infections of indigenous Cyprininae species in Japan were performed by immersion in and intraperitoneal injection of a CyHV-2 isolate. Although Edonishiki, a variety of goldfish, immersed with the virus showed a cumulative mortality of 90%, no mortality was observed in ginbuna C. auratus langsdorfii, nagabuna C. auratus buergeri, nigorobuna C. auratus grandoculis and common carp Cyprinus carpio. Cumulative mortality was 100, 20 and 10% in intraperitoneally injected Edonishiki, ginbuna and nagabuna, respectively. Furthermore all Edonishiki immersed with the virus died. However, even after stimuli of sudden temperature changes, the immersed ginbuna and nagabuna did not die. Moreover no mortality was observed in co-reared Ranchu, another variety of goldfish, with immersed ginbuna and nagabuna although all three Ranchu co-reared with immersed Edonishiki died. CyHV-2 DNA was detected and the virus was re-isolated from all dead fish. Moreover CyHV-2 DNA was detected from some of the surviving Carassius spp. These results revealed that susceptibility of Japanese indigenous Cyprininae fish species to CyHV-2 is much lower than for goldfish. In addition, ability of replication of CyHV-2 might be different among Carassius fish species.

  20. Impact of salinity on early life history traits of three estuarine fish species in Senegal

    Science.gov (United States)

    Labonne, Maylis; Morize, Eric; Scolan, Pierre; Lae, Raymond; Dabas, Eric; Bohn, Marcel

    2009-05-01

    The adaptive mechanisms on the early life stages of fishes to hypersaline stress are still poorly understood and probably determine the resistance of a population to disruption, compared with other less plastic species. The Casamance River in Senegal is an ideal location to test the adaptation to salinity as a dam was built in 1998 to exclude saline water intrusion. This lowered the salinity from 70 to 5 upstream and 60 downstream. The salinity influence on the growth in the early life of three West African fish species ( Ethmalosa fimbriata, Sarotherodon melanotheron, and Tilapia guineensis) was studied using the width of microstructures in the otoliths and the individual migratory behaviour analysed from strontium (Sr) to calcium (Ca) ratios in the otoliths. The Sr:Ca ratio was quantified along individual transects measured from the posterior edge of the otolith to the core. The fishes were sampled on both sides of the dam that separated water with low salinity upstream from metahaline and hyperhaline water downstream. The results showed that salinity has different influence on the growth of each species. Ethmalosa fimbriata has the highest growth during the first 180 days in the freshwaters, indicating growth inhibition in the hyperhaline areas. For the two other species no growth difference were found. The Sr/Ca ratio varied widely, in Tilapia and Sarotherodon from below the dam. Individual life histories were more heterogeneous than upstream and showed a crossing of the dam for some individuals which could reach half of the fishes analysed. On the contrary in E. fimbriata, despite the large range of salinity, identical Sr/Ca profiles were found both upstream and downstream. This indicated that Sr/Ca ratio was not appropriate to evaluate life history patterns linked to salinity for this specie.

  1. Ocean acidification alters the otoliths of a pantropical fish species with implications for sensory function.

    Science.gov (United States)

    Bignami, Sean; Enochs, Ian C; Manzello, Derek P; Sponaugle, Su; Cowen, Robert K

    2013-04-30

    Ocean acidification affects a wide diversity of marine organisms and is of particular concern for vulnerable larval stages critical to population replenishment and connectivity. Whereas it is well known that ocean acidification will negatively affect a range of calcareous taxa, the study of fishes is more limited in both depth of understanding and diversity of study species. We used new 3D microcomputed tomography to conduct in situ analysis of the impact of ocean acidification on otolith (ear stone) size and density of larval cobia (Rachycentron canadum), a large, economically important, pantropical fish species that shares many life history traits with a diversity of high-value, tropical pelagic fishes. We show that 2,100 μatm partial pressure of carbon dioxide (pCO2) significantly increased not only otolith size (up to 49% greater volume and 58% greater relative mass) but also otolith density (6% higher). Estimated relative mass in 800 μatm pCO2 treatments was 14% greater, and there was a similar but nonsignificant trend for otolith size. Using a modeling approach, we demonstrate that these changes could affect auditory sensitivity including a ∼50% increase in hearing range at 2,100 μatm pCO2, which may alter the perception of auditory information by larval cobia in a high-CO2 ocean. Our results indicate that ocean acidification has a graded effect on cobia otoliths, with the potential to substantially influence the dispersal, survival, and recruitment of a pelagic fish species. These results have important implications for population maintenance/replenishment, connectivity, and conservation efforts for other valuable fish stocks that are already being deleteriously impacted by overfishing.

  2. Effects of fishing technique on assessing species composition in aquatic systems in semi-arid Brazil

    Directory of Open Access Journals (Sweden)

    ESF Medeiros

    Full Text Available In most ecological field research, appropriate sampling is critical for the understanding of processes underlying fish populations and communities, and is even more important in heterogeneous environments such as the aquatic systems of the semi-arid region of Brazil. This study intends to make a contribution to the development of sampling programs and gear selection in aquatic systems of semi-arid Brazil by evaluating the effects of different fishing techniques on the assessment of richness and composition of the fish fauna in selected aquatic environments. Six sites were selected to represent typical artificial (reservoirs and natural (intermittent streams environments and four different types of sampling gear were applied to each site during four occasions. The present study shows that when selecting sampling techniques to be used in aquatic systems in semi-arid Brazil, one must consider the objectives of the study, e.g. ecological or taxonomic, in order to decide on inclusion of rare species in the sampling population. Also, the effect of the sampling gear on natural abundances of fish must be considered given that some sampling techniques are highly detrimental to fish population numbers.

  3. Spatial variation in elemental composition of otoliths of three species of fish (family Sparidae)

    Science.gov (United States)

    Gillanders, B. M.; Kingsford, M. J.

    2003-08-01

    Determining the nursery habitat of fishes that have moved from estuarine nursery habitats is difficult. The elemental fingerprints of otoliths of three species of sparids were determined to investigate their utility as a natural tag of the nursery habitat. Juvenile Pagrus auratus (snapper), Rhabdosargus sarba (tarwhine) and Acanthopagrus australis (bream) were collected from two sites in each of 15, six and three estuaries, respectively, and their otoliths analysed by solution-based inductively coupled plasma-mass spectrometry. Significant differences in otolith chemistry were found for all three species of juveniles collected from different estuaries. The same patterns among estuaries were not seen for all species, although it was not possible to sample the same sites within an estuary for all species. For bream, significant differences in otolith chemistry were found among all three estuaries, whereas for tarwhine the six estuaries were separated into three groups. For snapper, a number of estuaries could be separated, but there was some overlap for other estuaries. All three species were collected from the same site within one estuary and their otoliths analysed. Significant differences were found among species, but the implication of this finding remains unclear as the three species show differences in microhabitat use and may also differ in age. Because the elemental fingerprints of juveniles vary among estuaries or groups of estuaries, the nursery or recruitment estuary of adult fish could now be determined by analysing the juvenile region of adult otoliths. Thus, connectivity between estuaries and open coastal populations could be determined. Such information will have major implications for fisheries management because it will provide information on the distance that fish have moved from their recruitment estuary and the number of estuaries that contribute to each adult population.

  4. Chromosomal diversity in three species of electric fish (Apteronotidae, Gymnotiformes) from the Amazon Basin.

    Science.gov (United States)

    Silva, Fernando Henrique Ramos; Pieczarka, Julio Cesar; Cardoso, Adauto Lima; da Silva, Patrícia Corrêa; de Oliveira, Jonas Alves; Nagamachi, Cleusa Yoshiko

    2014-10-01

    Cytogenetic studies were carried out on samples of Parapteronotus hasemani, Sternarchogiton preto and Sternarchorhamphus muelleri (Apteronotidae, Gymnotiformes) from the Amazon basin. The first two species exhibited both a 2n = 52 karyotype, but differed in their karyotypic formulae, distribution of constitutive heterochromatin, and chromosomal location of the NOR. The third species, Sternarchorhamphus muelleri, was found to have a 2n = 32 karyotype. In all three species the DAPI and chromomycin A3 staining results were consistent with the C-banding results and nucleolar organizer region (NOR) localization. The 18S rDNA probe confirmed that there was only one pair of ribosomal DNA cistron bearers per species. The telomeric probe did not reveal interstitial telomeric sequences (ITS). The karyotypic differences among these species can be used for taxonomic identification. These data will be useful in future studies of these fishes and help understanding the phylogenetic relationships and chromosomal evolution of the Apteronotidae.

  5. Morphometrics and levels of infections of digeneans in belonid fish species off the coast of Tunisia.

    Science.gov (United States)

    Châari, M; Derbel, H; Neifar, L

    2016-09-01

    Three species of belonid fish, Belone belone gracilis Lowe, 1839, Belone svetovidovi Collette & Parin, 1970 and Tylosurus acus imperialis (Rafinesque, 1810), caught off the eastern Tunisian coast were infected with eight species of Digenea. Among these, four species were commonly found in B. b. gracilis and are new host records for B. svetovidovi. They are: Lecithostaphylus retroflexus (Molin, 1859), Tergestia acanthocephala (Stossich, 1887) Stossich, 1899 and Aponurus laguncula Looss, 1907 in the intestine, and the metacercaria Condylocotyla pilodora Pearson and Prévot, 1985 in the pericardial sac. Four other digenean species were recorded from T. a. imperialis: Lecithostaphylus tylosuri Châari et al., 2013 and Tetrochetus coryphaenae Yamaguti, 1934 in the intestine, Oesophagotrema mediterranea Châari et al., 2011 in the oesophagus and vomer teeth, and Sclerodistomoides pacificus Kamegai, 1971 in the gall bladder. Tetrochetus coryphaenae and S. pacificus represent new host and geographical records. The spatial variation of digenean parasites within belonid host species is discussed.

  6. Novel brominated flame retardants and dechloranes in three fish species from the St. Lawrence River, Canada.

    Science.gov (United States)

    Houde, Magali; Berryman, David; de Lafontaine, Yves; Verreault, Jonathan

    2014-05-01

    Restrictions in the utilization of polybrominated diphenyl ether (PBDE) mixtures have led to the increased usage of alternative flame retardant additives in a wide range of commercial applications. The present study examined the occurrence of established and emerging flame retardants (FRs) in fish from a densely-populated urbanized sector of the St. Lawrence River (Montreal, Quebec, Canada). Thirty-eight PBDE congeners and sixteen emerging FRs were determined in fish belonging to three predatory species (yellow perch, northern pike, and muskellunge). The ∑PBDE in fish were up to 24,115 ng/g lipid weight (l.w.) in the apex predator muskellunge. Twelve emerging FRs including bis(2-ethylhexyl)-tetrabromophthalate (BEHTBP), pentabromoethylbenzene (PBEB), Dechlorane Plus (anti and syn), dechloranes (Dec) 602, Dec 604, Dec 604 Compound B (Dec 604 CB), and Chlordene Plus (CP) were detected (>0.01 ng/gl.w.) in the liver of muskellunge and northern pike but not in yellow perch homogenates. This is the first report of Dec 604 CB in any fish species. The bioavailability of these FRs in human-impacted aquatic ecosystems warrants further environmental assessment and toxicity testing.

  7. Evaluation of a Method for Quantifying Eugenol Concentrations in the Fillet Tissue from Freshwater Fish Species.

    Science.gov (United States)

    Meinertz, Jeffery R; Schreier, Theresa M; Porcher, Scott T; Smerud, Justin R

    2016-01-01

    AQUI-S 20E(®) (active ingredient, eugenol; AQUI-S New Zealand Ltd, Lower Hutt, New Zealand) is being pursued for approval as an immediate-release sedative in the United States. A validated method to quantify the primary residue (the marker residue) in fillet tissue from AQUI-S 20E-exposed fish was needed. A method was evaluated for determining concentrations of the AQUI-S 20E marker residue, eugenol, in freshwater fish fillet tissue. Method accuracies from fillet tissue fortified at nominal concentrations of 0.15, 1, and 60 μg/g from six fish species ranged from 88-102%. Within-day and between-day method precisions (% CV) from the fortified tissue were ≤8.4% CV. There were no coextracted compounds from the control fillet tissue of seven fish species that interfered with eugenol analyses. Six compounds used as aquaculture drugs did not interfere with eugenol analyses. The lower limit of quantitation (LLOQ) was 0.012 μg/g. The method was robust, i.e., in most cases, minor changes to the method did not impact method performance. Eugenol was stable in acetonitrile-water (3 + 7, v/v) for at least 14 days, in fillet tissue extracts for 4 days, and in fillet tissue stored at ~ -80°C for at least 84 days.

  8. Evaluation of a method for quantifying eugenol concentrations in the fillet tissue from freshwater fish species

    Science.gov (United States)

    Meinertz, Jeffery R.; Schreier, Theresa M.; Porcher, Scott T.; Smerud, Justin R.

    2016-01-01

    AQUI-S 20E® (active ingredient, eugenol; AQUI-S New Zealand Ltd, Lower Hutt, New Zealand) is being pursued for approval as an immediate-release sedative in the United States. A validated method to quantify the primary residue (the marker residue) in fillet tissue from AQUI-S 20E–exposed fish was needed. A method was evaluated for determining concentrations of the AQUI-S 20E marker residue, eugenol, in freshwater fish fillet tissue. Method accuracies from fillet tissue fortified at nominal concentrations of 0.15, 1, and 60 μg/g from six fish species ranged from 88–102%. Within-day and between-day method precisions (% CV) from the fortified tissue were ≤8.4% CV. There were no coextracted compounds from the control fillet tissue of seven fish species that interfered with eugenol analyses. Six compounds used as aquaculture drugs did not interfere with eugenol analyses. The lower limit of quantitation (LLOQ) was 0.012 μg/g. The method was robust, i.e., in most cases, minor changes to the method did not impact method performance. Eugenol was stable in acetonitrile–water (3 + 7, v/v) for at least 14 days, in fillet tissue extracts for 4 days, and in fillet tissue stored at ~ −80°C for at least 84 days.

  9. Predator avoidance, microhabitat shift, and risk-sensitive foraging in larval dragonflies.

    Science.gov (United States)

    Pierce, C L

    1988-10-01

    Dragonfly larvae (Odonata: Anisoptera) are often abundant in shallow freshwater habitats and frequently co-occur with predatory fish, but there is evidence that they are underutilized as prey. This suggests that species which successfully coexist with fish may exhibit behaviors that minimize their risk of predation. I conducted field and laboratory experiments to determine whether: 1) dragonfly larvae actively avoid fish, 2) microhabitat use and foraging success of larvae are sensitive to predation risk, and 3) vulnerability of larvae is correlated with microhabitat use. I experimentally manipulated the presence of adult bluegills (Lepomis macrochirus) in defaunated patches of littoral substrate in a small pond to test whether colonizing dragonfly larvae would avoid patches containing fish. The two dominant anisopteran species, Tetragoneuria cynosura and Ladona deplanata (Odonata: Libellulidae), both strongly avoided colonizing patches where adult bluegills were present. Laboratory experiments examined the effects of diel period and bluegills on microhabitat use and foraging success, using Tetragoneuria, Ladona and confamilial Sympetrum semicictum, found in a nearby fishless pond. Tetragoneuria and Ladona generally occupied microhabitats offering cover, whereas Sympetrum usually occupied exposed locations. Bluegills induced increased use of cover in all three species, and use of cover also tended to be higher during the day than at night. Bluegills depressed foraging in Tetragoneuria and to a lesser extent in Ladona, but foraging in Sympetrum appeared unaffected. Other laboratory experiments indicated that Sympetrum were generally more vulnerable than Tetragoneuria or Ladona to bluegill predation, and that vulnerability was positively correlated with use of exposed microhabitats. Both fixed (generally low use of exposed microhabitats, diel microhabitat shifts) and reactive (predator avoidance, predator-sensitive microhabitat shifts) behavioral responses appear to

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

    Science.gov (United States)

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

    2014-09-01

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

  11. Testing for synchrony in recruitment among four Lake Michigan fish species

    Science.gov (United States)

    Bunnell, David; Höök, Tomas O.; Troy, Cary D.; Liu, Wentao; Madenjian, Charles P.; Adams, Jean V.

    2017-01-01

    In the Great Lakes region, multiple fish species display intra-specific spatial synchrony in 28 recruitment success, with inter-annual climate variation hypothesized as the most likely driver. 29 In Lake Michigan, we evaluated whether climatic or other physical variables could also induce 30 spatial synchrony across multiple species, including bloater (Coregonus hoyi), rainbow smelt 31 (Osmerus mordax), yellow perch (Perca flavescens), and alewife (Alosa pseudoharengus). The 32 residuals from stock-recruitment relationships revealed yellow perch recruitment to be correlated 33 with recruitment of both rainbow smelt (r = 0.37) and alewife (r = 0.36). Across all four species, 34 higher than expected recruitment occurred in 5 years between 1978 and 1987 and then switched 35 to lower than expected recruitment in 5 years between 1996 and 2004. Generalized additive 36 models revealed warmer spring and summer water temperatures and lower wind speeds 37 corresponded to higher than expected recruitment for the nearshore-spawning species, and 38 overall variance explained ranged from 14% (yellow perch) to 61% (alewife). For all species 39 but rainbow smelt, higher recruitment also occurred in extremely high or low years of the North 40 Atlantic Oscillation index. Future development of indices that describe the physical Great Lakes 41 environment could improve understanding of how climate can synchronize fish populations 42 within and across species.

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

    Science.gov (United States)

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

    2012-06-01

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

  13. Variability of PCB burden in 5 fish and sharks species of the French Mediterranean continental slope.

    Science.gov (United States)

    Cresson, Pierre; Fabri, Marie Claire; Miralles, Françoise Marco; Dufour, Jean-Louis; Elleboode, Romain; Sevin, Karine; Mahé, Kelig; Bouchoucha, Marc

    2016-05-01

    Despite being generally located far from contamination sources, deep marine ecosystems are impacted by chemicals like PCB. The PCB contamination in five fish and shark species collected in the continental slope of the Gulf of Lions (NW Mediterranean Sea) was measured, with a special focus on intra- and interspecific variability and on the driving factors. Significant differences occurred between species. Higher values were measured in Scyliorhinus canicula, Galeus melastomus and Helicolenus dactylopterus and lower values in Phycis blennoides and Lepidorhombus boscii. These differences might be explained by specific abilities to accumulate and eliminate contaminant, mostly through cytochrome P450 pathway. Interindividual variation was also high and no correlation was observed between contamination and length, age or trophic level. Despite its major importance, actual bioaccumulation of PCB in deep fish is not as documented as in other marine ecosystems, calling for a better assessment of the factors driving individual bioaccumulation mechanisms and originating high variability in PCB contamination.

  14. Morphometric and molecular descriptions of three new species of Hysterothylacium (Nematoda: Raphidascarididae) from Australian marine fish.

    Science.gov (United States)

    Shamsi, S

    2017-09-01

    Three new species of Hysterothylacium Ward & Magath, 1917, including H. australe, H. kajikiae and H. brucei, from Australian marine fish are described and illustrated by light microscopy followed by genetic characterization of their first and second internal transcribed spacers (ITS-1 and ITS-2, respectively). This is the first study reporting ITS sequence data for adult Hysterothylacium spp. in Australia, which provides an insight into the identification of some of the Hysterothylacium larval types. Alignment of ITS sequences of these species with Hysterothylacium larval types previously reported in Australia showed that fourth-stage Hysterothylacium larval type XI from Seriola lalandi and third-stage Hysterothylacium larval type X from Sphyraene novae-hollandiae are identical with ITS sequences of H. australe, suggesting that these fish are natural intermediate/paratenic hosts of H. australe.

  15. Selenium and mercury molar ratios in saltwater fish from New Jersey: Individual and species variability complicate use in human health fish consumption advisories☆

    Science.gov (United States)

    Burger, Joanna; Gochfeld, Michael

    2014-01-01

    Balancing risk versus benefits to humans and other organisms from consuming fish is a national concern in the USA, as well as in many other parts of the world. Protecting public health is both a federal and state responsibility, and states respond by issuing fish consumption advisories, particularly for mercury. Recently it has been emphasized that the protective role of selenium against mercury toxicity depends on their molar ratios, which should be evaluated as an indication of selenium’s protective capacity, and incorporated in risk assessments for fish consumption. However, there is no single “protective” ratio agreed upon. In this paper we examine the selenium:mercury (Se:Hg) molar ratios in a wide range of saltwater fish caught and eaten by recreational fishers along the New Jersey coast. We were particularly interested in interspecific and intraspecific variability, and whether the molar ratios were consistent within a species, allowing for its use in managing risk. The selenium–mercury molar ratio showed significant variation among and within fish species. The molar ratio decreased with the size of the fish species, decreased with the mercury levels, and within a fish species, the selenium:mercury ratio decreased with fish size. As an essential element, selenium undergoes some homeostatic regulation, but it is also highly toxic. Within species, mercury level tends to increase with size, accounting for the negative relationship between size and ratio. This variability may make it difficult to use the selenium:mercury molar ratio in risk assessment, risk management, and risk communication at this time, and more information is needed on how mercury and selenium actually interact and on the relationship between the molar ratios and health outcomes. PMID:22405995

  16. Improvement scheme for the determination of arsenic species in mussel and fish tissues

    DEFF Research Database (Denmark)

    Lagarde, F.; Amran, M. B.; Leroy, M. J. F.

    1999-01-01

    Six interlaboratory studies were organised by the Standard, Measurement and Testing Programme of the European Commission on the determination of arsenic species (arsenobetaine, arsenocholine, monomethylarsonic acid, dimethylarsinic acid, As(III) and As(V)) in marine matrices and soil. A step...... and at the end of the six campaigns allowed the certification of a reference material of tuna-fish tissue (BCR-CRM 627) for its total arsenic, arsenobetaine and dimethylarsinic acid contents....

  17. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Northwest). Amphipods.

    Science.gov (United States)

    1986-08-01

    Body slender and resembling that of a 1973). praying mantis (except for whale lice). Marine. Includes skeleton shrimp Suborder Caprellidea. MORPHOLOGY...Abdomen not vestigial. Body neither slender nor resembling that of a praying mantis . ...... 2 REASON FOR INCLUSION IN SERIES lb. Pereon with six...according to Smith and Mudd (1976) and patchy, small localized perturbations for other fish species, as well as are likely to create more patchiness, shrimp

  18. Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (South Atlantic). Striped Bass

    Science.gov (United States)

    1989-12-01

    the sides (Werner 1980). Osteological vomer and paiatines (Hardy 1978). differences are also evident in the three species (Woolcott 1957; Harrell 1984...Percichthyidae) by means of osteological patterns, meristics and Holland, B.F., Jr., and G.F. Yelverton. 1973. morphometrics. Ph.D. Dissertation. Uni...1957. Comparative osteology Striped Bass Subcommittee of the House of of serranid fishes of the genus Roccus Representatives. 9 pp. (Mitchill). Copeia

  19. Changes of bacterioplankton apparent species richness in two ornamental fish aquaria

    OpenAIRE

    2013-01-01

    We analysed the 16S rRNA gene diversity within the bacterioplankton community in the water column of the ornamental fish Pterophyllum scalare and Archocentrus nigrofasciatus aquaria during a 60-day growth experiment in order to detect any dominant bacterial species and their possible association with the rearing organisms. The basic physical and chemical parameters remained stable but the bacterial community at 0, 30 and 60 days showed marked differences in bacterial cell abundance and divers...

  20. Sex determination studies in two species of teleost fish, Oreochromis niloticus and Leporinus elongatus

    OpenAIRE

    Baroiller, Jean-Francois; Nakayama, Ichiro; FORESTI,FAUSTO; Chourrout, Daniel

    1996-01-01

    Genetic analyses of sex determination have identified sex chromosomes in many teleost fish species. However, there are several cases for which sex ratios do not fit perfectly with the expectations of heterogametic systems, suggesting the influence of either minor sex determining genes or environmental influences on the process of sex differentiation. The frequent absence of sex chromosome markers makes the identification of minor sex-determining genes very difficult. It is easier to test firs...

  1. Retinol, alpha-tocopherol and fatty acid content in Bulgarian black Sea fish species

    OpenAIRE

    Stancheva, M; Galunska, B.; Dobreva, A. D.; Merdzhanova, A.

    2012-01-01

    The aim of the present study was to measure and evaluate the total lipids, fatty acid profile, retinol content and alpha-tocopherol content in the edible tissue of four commercially important fish species from the Bulgarian Black sea: Sprat (Sprattus sprattus), Round Goby (Neogobius rattan), Black Sea Horse Mackerel (Trahurus medditeraneus ponticus) and Shad (Alosa pontica). Fat soluble vitamins were analyzed simultaneously usi...

  2. Some philometrid nematodes (Philometridae), including four new species of Philometra, from marine fishes off New Caledonia

    OpenAIRE

    Moravec, F.; Justine, Jean-Lou

    2008-01-01

    Examinations of marine fishes off New Caledonia, South Pacific, carried out in 2003-2006, yielded some nematodes of the genus Philometra Costa, 1845, including the following three new species: P. cyanopodi sp. nov. (males and subgravid females) and P. lethrini sp. nov. (males and subgravid females) from the gonads of Epinephelus cyanopodus (Richardson) (Serranidae) and Lethrinus genivittatus Valenciennes (Lethrinidae), respectively, and P. lagocephali sp. nov. (gravid female) from the abdomin...

  3. Two species of Philometra (Nematoda, Philometridae) from serranid fishes off New Caledonia

    OpenAIRE

    Moravec, F.; Justine, Jean-Lou

    2005-01-01

    Two nematode species of the genus Philometra Costa, 1845, P. ocularis Moravec, Ogawa, Suzuki, Miyazaki et Donai, 2002 (gravid and nongravid females) and P. lateolabracis (Yamaguti, 1935) (males and nongravid females), were recorded from the ocular cavity and ovaries, respectively, of serranid fishes (Serranidae, Perciformes) off New Caledonia, South Pacific. The gravid female of P. ocularis was found to attain a body length up to 96 mm, (as compared to 59 mm in the original description). The ...

  4. Propensity of marine reserves to reduce the evolutionary effects of fishing in a migratory species

    OpenAIRE

    Dunlop, E.S.; Baskett, M. L.; M. Heino; Dieckmann, U.

    2009-01-01

    Evolutionary effects of fishing can have unwanted consequences diminishing a fishery's value and sustainability. Reserves, or no-take areas, have been proposed as a management tool for reducing fisheries-induced selection, but their effectiveness for migratory species has remained unexplored. Here we develop an eco-genetic model to predict the effects of marine reserves on fisheries-induced evolution under migration. To represent a stock that undergoes an annual migration between feeding and ...

  5. Genome analysis of Betanodavirus from cultured marine fish species in Malaysia.

    Science.gov (United States)

    Ransangan, Julian; Manin, Benny Obrain

    2012-04-23

    Betanodavirus is the causative agent of the viral nervous necrosis (VNN) or viral encephalopathy and retinopathy disease in marine fish. This disease is responsible for most of the mass mortalities that occurred in marine fish hatcheries in Malaysia. The genome of this virus consists of two positive-sense RNA molecules which are the RNA1 and RNA2. The RNA1 molecule contains the RdRp gene which encodes for the RNA-dependent RNA polymerase and the RNA2 molecule contains the Cp gene which encodes for the viral coat protein. In this study, total RNAs were extracted from 32 fish specimens representing the four most cultured marine fish species in Malaysia. The fish specimens were collected from different hatcheries and aquaculture farms in Malaysia. The RNA1 was successfully amplified using three pairs of overlapping PCR primers whereas the RNA2 was amplified using a pair of primers. The nucleotide analysis of RdRp gene revealed that the Betanodavirus in Malaysia were 94.5-99.7% similar to the RGNNV genotype, 79.8-82.1% similar to SJNNV genotype, 81.5-82.4% similar to BFNNV genotype and 79.8-80.7% similar to TPNNV genotype. However, they showed lower similarities to FHV (9.4-14.2%) and BBV (7.2-15.7%), respectively. Similarly, the Cp gene revealed that the viruses showed high nucleotide similarity to RGNNV (95.9-99.8%), SJNNV (72.2-77.4%), BFNNV (80.9-83.5%), TPNNV (77.2-78.1%) and TNV (75.1-76.5%). However, as in the RdRp gene, the coat protein gene was highly dissimilar to FHV (3.0%) and BBV (2.6-4.1%), respectively. Based on the genome analysis, the Betanodavirus infecting cultured marine fish species in Malaysia belong to the RGNNV genotype. However, the phylogenetic analysis of the genes revealed that the viruses can be further divided into nine sub-groups. This has been expected since various marine fish species of different origins are cultured in Malaysia.

  6. Assessing species boundaries using multilocus species delimitation in a morphologically conserved group of neotropical freshwater fishes, the Poecilia sphenops species complex (Poeciliidae.

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    Justin C Bagley

    Full Text Available Accurately delimiting species is fundamentally important for understanding species diversity and distributions and devising effective strategies to conserve biodiversity. However, species delimitation is problematic in many taxa, including 'non-adaptive radiations' containing morphologically cryptic lineages. Fortunately, coalescent-based species delimitation methods hold promise for objectively estimating species limits in such radiations, using multilocus genetic data. Using coalescent-based approaches, we delimit species and infer evolutionary relationships in a morphologically conserved group of Central American freshwater fishes, the Poecilia sphenops species complex. Phylogenetic analyses of multiple genetic markers (sequences of two mitochondrial DNA genes and five nuclear loci from 10/15 species and genetic lineages recognized in the group support the P. sphenops species complex as monophyletic with respect to outgroups, with eight mitochondrial 'major-lineages' diverged by ≥2% pairwise genetic distances. From general mixed Yule-coalescent models, we discovered (conservatively 10 species within our concatenated mitochondrial DNA dataset, 9 of which were strongly supported by subsequent multilocus Bayesian species delimitation and species tree analyses. Results suggested species-level diversity is underestimated or overestimated by at least ~15% in different lineages in the complex. Nonparametric statistics and coalescent simulations indicate genealogical discordance among our gene tree results has mainly derived from interspecific hybridization in the nuclear genome. However, mitochondrial DNA show little evidence for introgression, and our species delimitation results appear robust to effects of this process. Overall, our findings support the utility of combining multiple lines of genetic evidence and broad phylogeographical sampling to discover and validate species using coalescent-based methods. Our study also highlights the

  7. Assessing species boundaries using multilocus species delimitation in a morphologically conserved group of neotropical freshwater fishes, the Poecilia sphenops species complex (Poeciliidae).

    Science.gov (United States)

    Bagley, Justin C; Alda, Fernando; Breitman, M Florencia; Bermingham, Eldredge; van den Berghe, Eric P; Johnson, Jerald B

    2015-01-01

    Accurately delimiting species is fundamentally important for understanding species diversity and distributions and devising effective strategies to conserve biodiversity. However, species delimitation is problematic in many taxa, including 'non-adaptive radiations' containing morphologically cryptic lineages. Fortunately, coalescent-based species delimitation methods hold promise for objectively estimating species limits in such radiations, using multilocus genetic data. Using coalescent-based approaches, we delimit species and infer evolutionary relationships in a morphologically conserved group of Central American freshwater fishes, the Poecilia sphenops species complex. Phylogenetic analyses of multiple genetic markers (sequences of two mitochondrial DNA genes and five nuclear loci) from 10/15 species and genetic lineages recognized in the group support the P. sphenops species complex as monophyletic with respect to outgroups, with eight mitochondrial 'major-lineages' diverged by ≥2% pairwise genetic distances. From general mixed Yule-coalescent models, we discovered (conservatively) 10 species within our concatenated mitochondrial DNA dataset, 9 of which were strongly supported by subsequent multilocus Bayesian species delimitation and species tree analyses. Results suggested species-level diversity is underestimated or overestimated by at least ~15% in different lineages in the complex. Nonparametric statistics and coalescent simulations indicate genealogical discordance among our gene tree results has mainly derived from interspecific hybridization in the nuclear genome. However, mitochondrial DNA show little evidence for introgression, and our species delimitation results appear robust to effects of this process. Overall, our findings support the utility of combining multiple lines of genetic evidence and broad phylogeographical sampling to discover and validate species using coalescent-based methods. Our study also highlights the importance of testing for

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

    Science.gov (United States)

    Katz, Rachel A.; Freeman, Mary C.

    2015-01-01

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

  9. Development of aquarium fish models for environmental carcinogenesis: tumor induction in seven species

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, W.E.; Overstreet, R.M.; Fournie, J.W.; Walker, W.W.

    1985-08-01

    For small fish species to be utilized as models for carcinogenicity testing they should be capable of developing neoplasms, preferably in multiple tissues, when exposed to known carcinogens. Seven species of small fish were exposed to methylazoxymethanol acetate (MAM-Ac) and tumor development was monitored. Specimens 6-10 days old were exposed to nominal concentrations of MAM-Ac up to 100 mg 1( ) for 2 h, then transferred to carcinogen-free water. Hepatic neoplasms developed in the Japanese medaka, guppy, and sheepshead minnow. All tumors were diagnosed in specimens within 1 year post-exposure. Early signs of liver tumors appeared in medaka and guppy at about 1 month post-exposure. These studies show that both medaka and guppy would be good models because they appear sensitive to carcinogens, develop tumors in multiple tissues and are easy to breed and maintain. Certain other small fish species also may prove to be good models because of habitat preferences, breeding strategies, or genetic attributes.

  10. Host-parasite interaction between crustaceans of six fish species from the Brazilian Amazon

    Directory of Open Access Journals (Sweden)

    Huann Carllo Gentil Vasconcelos

    2016-07-01

    Full Text Available Host-parasite interactions between crustaceans and six fish species (Psectrogaster falcata, Ageneiosus ucayalensis, Acestrorhynchus falcirostris, Hemiodus unimaculatus, Serrasalmus gibbus and Geophagus proximus from a reservoir in eastern Amazon, northern Brazil, were investigated. Eight hundred and seventy-eight parasites belonging to three crustacean species, Excorallana berbicensis, Argulus chicomendesi and Ergasilus turucuyus, which parasitized the hosts’ mouth, gills and tegument, were collected from 295 fish and examined. High infestation levels were caused by E. berbicensis on the body surface of the hosts. Excorallana berbicensis showed aggregate dispersion, except in S. gibbus, while E. turucuyus showed random dispersion in A. falcirostris. The host’s sex did not influence infestation by E. berbicensis, and high parasitism failed to affect the body conditions of the fish. In the case of some hosts, rainfall rates, temperature, dissolved oxygen levels and water pH affected the prevalence and abundance of E. berbicensis, the dominant parasite species. Results revealed that the environment and life-style of the hosts were determining factors in infestations by parasites. Current assay is the first report on E. berbicensis for the six hosts, as well as on A. chicomendesi for G. proximus and P. falcata.

  11. Mercury and selenium levels in 19 species of saltwater fish from New Jersey as a function of species, size, and season

    Science.gov (United States)

    Burger, Joanna; Gochfeld, Michael

    2014-01-01

    There are few data on risks to biota and humans from mercury levels in saltwater fish. This paper examines mercury and selenium levels in muscle of 19 species of fish caught by recreational fisherfolk off the New Jersey shore, as a function of species of fish, size, and season, and risk of mercury to consumers. Average mercury levels ranged from 0.01 ppm (wet weight) (Menhaden Brevoortia tyrannus) to 1.83 ppm (Mako Shark Isurus oxyrinchus). There were four categories of mercury levels: very high (only Mako), high (averaging 0.3–0.5 ppm, 3 species), medium (0.14–0.20 ppm, 10 species), and low (below 0.13 ppm, 5 species). Average selenium levels for the fish species ranged from 0.18 ppm to 0.58 ppm, and had lower variability than mercury (coefficient of variation=38.3 vs 69.1%), consistent with homeostatic regulation of this essential element. The correlation between mercury and selenium was significantly positive for five and negative for two species. Mercury levels showed significant positive correlations with fish size for ten species. Size was the best predictor of mercury levels. Selenium showed no consistent relationship to fish length. Over half of the fish species had some individual fish with mercury levels over 0.3 ppm, and a third had fish with levels over 0.5 ppm, levels that pose a human health risk for high end consumers. Conversely several fish species had no individuals above 0.5 ppm, and few above 0.3 ppm, suggesting that people who eat fish frequently, can reduce their risk from mercury by selecting which species (and which size) to consume. Overall, with the exception of shark, Bluefin Tuna (Thunnus thynnus), Bluefish (Pomatomus saltatrix) and Striped Bass (Morone saxatilis), the species sampled are generally medium to low in mercury concentration. Selenium:mercury molar ratios were generally above 1:1, except for the Mako shark. PMID:21292311

  12. [Finding of the bacterial species Edwardsiella tarda in the aquarium fish Betta splendens].

    Science.gov (United States)

    Vladík, P; Prouza, A; Vítovec, J

    1983-01-01

    A case of the mass occurrence of a disease in the aquarium fish species Betta splendens is described; morphologically the disease was characterized by the finding of large dermal changes located mainly in the dorsal part and by miliary granulomata in liver, spleen and kidneys. The granulomata consisted of epitheloid light cells with centrally located necrosis. Gram-negative bacteria with morphological and biochemical characteristics corresponding to the bacterial species Edwardsiella tarda were isolated from the kidneys, liver and from the dermal lesion. The characteristics of the strains isolated by us were compared with the reference Edwardsiella strain (Bth 1/64) obtained from the Czechoslovak collection of type cultures, Prague.

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

    Science.gov (United States)

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

    2014-03-01

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

  14. Prescription of antimicrobial drugs in Norwegian aquaculture with an emphasis on "new" fish species.

    Science.gov (United States)

    Grave, Kari; Hansen, Magne Kjerulf; Kruse, Hilde; Bangen, Marit; Kristoffersen, Anja Bråthen

    2008-02-01

    The usage of antimicrobial (AM) drugs in farmed fish in Norwegian aquaculture for the period 2000-2005 was investigated by using prescription data. These data were validated against national sales data of AM drugs sold for use in farmed fish and were found to be highly valid. The defined course dose (DCD) was applied as the unit of measurement to correct for the variations in the dosages between different AM drugs. The DCD(kg) was the amount of an AM drug recommended for the treatment of a 1-kg fish. The calculated number of prescribed DCD(kg)s is an estimate of the biomass of farmed fish that can be treated with a certain amount AM drug. In the present study, the number of prescriptions issued (i.e., numbers of initiated treatments), weight of active substance prescribed and biomass treated were applied to describe the usage. An increase, although modest, in the AM drug usage in Norwegian aquaculture was observed from 2002 to 2005. This increase was accounted for by new-farmed fish species (other than Atlantic salmon and rainbow trout), especially Atlantic cod. The increased usage of AM drugs in cod in the study period was significantly positively correlated to the biomass produced; even so from 2001 to 2005 the number of prescriptions for cod relative to the produced biomass declined. The AM drug usage in Atlantic halibut as well as the production varied during the study period. For other species such as turbot, coalfish and wolffish the usage of AM drugs was found to be negligible. "Mono-therapy" with quinolones may present a selective pressure in regard to development of quinolone resistance.

  15. Host range, host ecology, and distribution of more than 11800 fish parasite species

    Science.gov (United States)

    Strona, Giovanni; Palomares, Maria Lourdes D.; Bailly, Nicholas; Galli, Paolo; Lafferty, Kevin D.

    2013-01-01

    Our data set includes 38 008 fish parasite records (for Acanthocephala, Cestoda, Monogenea, Nematoda, Trematoda) compiled from the scientific literature, Internet databases, and museum collections paired to the corresponding host ecological, biogeographical, and phylogenetic traits (maximum length, growth rate, life span, age at maturity, trophic level, habitat preference, geographical range size, taxonomy). The data focus on host features, because specific parasite traits are not consistently available across records. For this reason, the data set is intended as a flexible resource able to extend the principles of ecological niche modeling to the host–parasite system, providing researchers with the data to model parasite niches based on their distribution in host species and the associated host features. In this sense, the database offers a framework for testing general ecological, biogeographical, and phylogenetic hypotheses based on the identification of hosts as parasite habitat. Potential applications of the data set are, for example, the investigation of species–area relationships or the taxonomic distribution of host-specificity. The provided host–parasite list is that currently used by Fish Parasite Ecology Software Tool (FishPEST, http://purl.oclc.org/fishpest), which is a website that allows researchers to model several aspects of the relationships between fish parasites and their hosts. The database is intended for researchers who wish to have more freedom to analyze the database than currently possible with FishPEST. However, for readers who have not seen FishPEST, we recommend using this as a starting point for interacting with the database.

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

    OpenAIRE

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

    2016-01-01

    In the past decade, significant efforts have been made to describe fish-habitat associations. However, most studies have oversimplified actual connections between fish assemblages and their habitats by using univariate correlations. The purpose of this study was to identify the features of habitat forming corals that facilitate and influences assemblages of associated species such as fishes. For this we developed three-dimensional models of colonies of Acropora cervicornis to estimate geometr...

  17. Integrated Taxonomy Reveals Hidden Diversity in Northern Australian Fishes: A New Species of Seamoth (Genus Pegasus.

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    Deborah Osterhage

    Full Text Available Fishes are one of the most intensively studied marine taxonomic groups yet cryptic species are still being discovered. An integrated taxonomic approach is used herein to delineate and describe a new cryptic seamoth (genus Pegasus from what was previously a wide-ranging species. Preliminary mitochondrial DNA barcoding indicated possible speciation in Pegasus volitans specimens collected in surveys of the Torres Strait and Great Barrier Reef off Queensland in Australia. Morphological and meristic investigations found key differences in a number of characters between P. volitans and the new species, P. tetrabelos. Further mt DNA barcoding of both the COI and the slower mutating 16S genes of additional specimens provided strong support for two separate species. Pegasus tetrabelos and P. volitans are sympatric in northern Australia and were frequently caught together in trawls at the same depths.

  18. Fish species of greatest conservation need in wadeable Iowa streams: current status and effectiveness of Aquatic Gap Program distribution models

    Science.gov (United States)

    Sindt, Anthony R.; Pierce, Clay; Quist, Michael C.

    2012-01-01

    Effective conservation of fish species of greatest conservation need (SGCN) requires an understanding of species–habitat relationships and distributional trends. Thus, modeling the distribution of fish species across large spatial scales may be a valuable tool for conservation planning. Our goals were to evaluate the status of 10 fish SGCN in wadeable Iowa streams and to test the effectiveness of Iowa Aquatic Gap Analysis Project (IAGAP) species distribution models. We sampled fish assemblages from 86 wadeable stream segments in the Mississippi River drainage of Iowa during 2009 and 2010 to provide contemporary, independent fish species presence–absence data. The frequencies of occurrence in stream segments where species were historically documented varied from 0.0% for redfin shiner Lythrurus umbratilis to 100.0% for American brook lampreyLampetra appendix, with a mean of 53.0%, suggesting that the status of Iowa fish SGCN is highly variable. Cohen's kappa values and other model performance measures were calculated by comparing field-collected presence–absence data with IAGAP model–predicted presences and absences for 12 fish SGCN. Kappa values varied from 0.00 to 0.50, with a mean of 0.15. The models only predicted the occurrences of banded darterEtheostoma zonale, southern redbelly dace Phoxinus erythrogaster, and longnose daceRhinichthys cataractae more accurately than would be expected by chance. Overall, the accuracy of the twelve models was low, with a mean correct classification rate of 58.3%. Poor model performance probably reflects the difficulties associated with modeling the distribution of rare species and the inability of the large-scale habitat variables used in IAGAP models to explain the variation in fish species occurrences. Our results highlight the importance of quantifying the confidence in species distribution model predictions with an independent data set and the need for long-term monitoring to better understand the

  19. Species-specific impacts of a small marine reserve on reef fish production and fishing productivity in the Turks and Caicos Islands

    OpenAIRE

    Tupper, M.H.; Rudd, M.A.

    2002-01-01

    Marine reserves are widely considered to potentially benefit reef fisheries through emigration, yet the empirical basis for predicting the extent of this for small reserves is weak. The effects of fishing pressure and habitat on biomass and catch per unit effort (CPUE) of three species of exploited reef fish were studied at South Caicos, Turks and Caicos Islands. Distribution and abundance of hogfish (Lachnolaimus maximus) and white margate (Haemulon album) were inversely correlated with cove...

  20. A histology-based fish health assessment to determine the health status and edibility of two indicator fish species from the Roodeplaat Dam

    OpenAIRE

    2011-01-01

    M.Sc. A comprehensive histology-based fish health assessment was implemented at the Roodeplaat Dam (RD), Pretoria, South Africa, to determine the health status of two fresh water fish species, Clarias gariepinus (n = 20) and Oreochromis mossambicus (n = 18), after exposure to pollutants. RD is known to be polluted, being impacted from two sewage treatment plants, industry, housing and agriculture all upstream of the reserve. Excessive nutrient loads, such as orthophosphate, resulted in the...

  1. Bayesian hierarchical model used to analyze regression between fish body size and scale size: application to rare fish species Zingel asper

    Directory of Open Access Journals (Sweden)

    Fontez B.

    2014-04-01

    Full Text Available Back-calculation allows to increase available data on fish growth. The accuracy of back-calculation models is of paramount importance for growth analysis. Frequentist and Bayesian hierarchical approaches were used for regression between fish body size and scale size for the rare fish species Zingel asper. The Bayesian approach permits more reliable estimation of back-calculated size, taking into account biological information and cohort variability. This method greatly improves estimation of back-calculated length when sampling is uneven and/or small.

  2. Biometric indices and size at first sexual maturity of eight alien fish species from Bangladesh

    Directory of Open Access Journals (Sweden)

    Md. Yeamin Hossain

    2016-09-01

    Full Text Available The biometric indices and size at first sexual maturity of eight alien fish species from several water bodies in Bangladesh were studied for the first time. A total of 273 individuals of eight alien fish species (Barbonymus gonionotus, Clarias gariepinus, Ctenopharyngodon idella, Cyprinus carpio, Hypophthalmichthys molitrix, H. nobilis, Oreochromis niloticus and Pangasianodon hypophthalmus were collected using traditional fishing gears from June 2014 to May 2015. Among the four condition factors (Allometric condition factor, Fulton’s condition factor, Relative condition factor, and Relative weight studied, Fulton’s condition factor was the best for assessing the well-being of these alien species in their natural habitat, based on the relationships of condition factors with body weight and total length. The calculated form factor was 0.0270 for B. gonionotus, 0.0077 for C. gariepinus, 0.0119 for C. idella, 0.0194 for C. carpio, 0.0101 for H. molitrix, 0.0092 for H. nobilis, 0.0158 for O. niloticus and 0.0105 for P. hypophthalmus. The size at first sexual maturity was estimated in TL as 12.30 cm for B. gonionotus, 25.53 cm for C. gariepinus, 32.80 cm for C. idella, 18.22 cm for C. carpio, 23.92 cm for H. molitrix, 30.18 cm for H. nobilis, 21.78 cm for O. niloticus, and 21.32 cm for P. hypophthalmus. The present study also calculates form factor and first sexual maturity of these alien species from different water-bodies world over. The findings of this study can be very helpful for sustainable management of these alien species in Bangladesh and similar ecosystems.

  3. Isotopic variation in five species of stream fishes under the influence of different land uses.

    Science.gov (United States)

    Carvalho, D R; Castro, D; Callisto, M; Moreira, M Z; Pompeu, P S

    2015-09-01

    The aim of this study was to test if changes in land use alter the isotopic signature of fish species, promoting changes in the trophic position and food resource partitioning between these consumers. Three different systems were investigated: pasture streams (n = 3), streams in sugar cane plantations (n = 3) and reference streams (n = 3). Fish species Aspidoras fuscoguttatus, Astyanax altiparanae, Characidium zebra, Hisonotus piracanjuba and Knodus moenkhausii were selected, and their nitrogen and carbon isotopic compositions were estimated to assess changes in the trophic level and partitioning of food items consumed. The composition of δ(13) C (‰) only differed among the land use categories for A. altiparanae, H. piracanjuba and K. moenkhausii. Resource partitioning was different for all species, with changes in the sources or proportions they consumed in each land use category, but only A. altiparanae introduced new food sources in large quantity in altered land uses. It is important to note, however, that the results from the resource partitioning analysis are limited due to large overlapping of isotopic signatures between the analysed food resources. All fish species exhibited variation in δ(15) N (‰), with the highest values found in streams under sugar cane or pasture influence. Despite the variation in nitrogen isotopic values, only C. zebra and H. piracanjuba displayed changes in trophic level. Therefore, it is believed that the increase in the δ(15) N (‰) value of the individuals collected in streams under the influence of sugar cane or pasture was due to the greater influence of livestock dung and chemical and organic fertilizers. The results also highlight the importance of studying consumer species along with all forms of resources available at each location separately, because the signatures of these resources also vary within different land uses.

  4. FRESHWATER FISH AND DECAPOD CRUSTACEAN POPULATIONS ON RÉUNION ISLAND, WITH AN ASSESSMENT OF SPECIES INTRODUCTIONS.

    Directory of Open Access Journals (Sweden)

    KEITH P.

    2002-01-01

    Full Text Available Streams of Réunion Island shelter with 26 fish species and 11 decapod crustacean species. Some species have been introduced (18%, some other are endemic to the island or to the Madagascar-Mascarenes region (16.2%, are originated from Indo-Pacific area (35.2% or from Indo-African area (27%. Gobiidae and Palaemonidae are the prevailing family in freshwaters, with the highest number of species. 16 species were introduced, mainly fishes, beginning at the turn of the 19th century, but only 4 of those have become acclimatised, while 7 have disappeared and the status of the other is uncertain.

  5. Summer distribution and species richness of non-native fishes in the mainstem Willamette River, oregon, 1944-2006

    Science.gov (United States)

    We reviewed the results of seven extensive and two reach-specific fish surveys conducted on the mainstem Willamette River between 1944 and 2006 to document changes in the summer distribution and species richness of non-native fishes through time and the relative abundances of the...

  6. Toxic and essential trace elemental contents in fish species from the Black Sea, Turkey.

    Science.gov (United States)

    Tuzen, Mustafa

    2009-08-01

    Toxic and essential element content of ten different fish species from the Black Sea were determined by atomic absorption spectrometry after microwave digestion method. The validation of the presented procedure is performed by the analysis of standard reference materials (NRCC-DORM 2 Dogfish Muscle). The relative standard deviations were found to be lower than 10%. Toxic element content in fish samples were found 25-84 microg/kg for mercury, 0.11-0.32 microg/g for arsenic, 0.28-0.87 microg/g for lead, 0.10-0.35 microg/g for cadmium, 1.14-3.60 microg/g for nickel. Trace element content in fish samples were found 36.2-145 microg/g for iron, 0.65-2.78 microg/g for copper, 2.76-9.10 microg/g for manganese, 38.8-93.4 microg/g for zinc, 0.19-0.85 microg/g for selenium, 0.63-1.74 microg/g for chromium. The levels of lead and cadmium in fish samples were higher than the recommended legal limits for human consumption.

  7. Culverts in paved roads as suitable passages for Neotropical fish species

    Directory of Open Access Journals (Sweden)

    Sergio Makrakis

    Full Text Available Improperly installed or poorly maintained culverts can pose a serious threat to fish by disrupting their habitat and endangering spawning success. Road culverts that are not designed for fish passage frequently can become obstacles. This can be especially problematic for migratory species, but can lead to fragmentation of resident populations as well. This study evaluated 40 culverts of 29 sites within a 25-km radius from Toledo city, Paraná State, southern Brazil, with respect to their likely effects on movement of the local ichthyofauna. We collected data on the shape and length of culverts, culvert material, waterfall height, water column depth, slope, and estimated flow velocity. Culverts were categorized by level of barrier risk for upstream migration: high, medium, low, and impassable, as well as the type of barrier posed (fall height, depth, length and velocity. Most of culverts analyzed were considered potential barriers to fish movement, with 45% classified as impassible, 45% as high risk, 10% as medium risk, and no culverts as low risk. Brazilian culverts as fishways will require additional monitoring and studies to corroborate the premises proposed in the present study. Road culvert projects that are properly built and maintained will be able to simultaneously improve function of roadways and protect fish populations.

  8. Multiple factors and thresholds explaining fish species distributions in lowland streams

    Directory of Open Access Journals (Sweden)

    Cristina Trigal

    2015-07-01

    Full Text Available Appropriate restoration and conservation measures require a good understanding of the factors limiting the distribution of species, the presence of steep changes in the distribution along environmental gradients and the effect of environmental interactions on species distribution. We used 12 environmental variables describing connectivity, hydrology, climate and stream morphology, to model the distributions of 17 fish species from 2005 Swedish stream sites that were sampled between 2000 and 2011. Modeling was performed using boosted regression trees and random forest, two machine learning techniques to assess the relationship between species distributions and their environment. Temperature, width and connectivity (minimum distance to lake or the sea and water discharge, were the most important variables explaining changes in species distribution at large spatial scales. Response curves of fitted occurrence probabilities along predictors often showed abrupt changes, however, clear threshold effects were difficult to detect. Our results show also differences across species and even in the outcomes of the two algorithms, implying that a simultaneous assessment of multiple species may provide a better signal of ecosystem change than the use of surrogate species.

  9. Common descent of B chromosomes in two species of the fish genus Prochilodus (Characiformes, Prochilodontidae).

    Science.gov (United States)

    Voltolin, T A; Pansonato Alves, J C; Senhorini, J A; Foresti, F; Camacho, J P M; Porto-Foresti, F

    2013-01-01

    To ascertain the origin of B chromosomes in 2 fish species of the genus Prochilodus, i.e. P. lineatus and P. nigricans, we microdissected them and generated B-specific DNA probes. These probes were used to perform chromosome painting in both species and in 3 further ones belonging to the same genus (P. argenteus, P. brevis and P. costatus). Both probes hybridized with the B chromosomes in P. lineatus and P. nigricans, but with none of the chromosomes in the 5 species. This indicates that the B chromosomes have low similarity with DNAs located in the A chromosomes and suggests the possibility that the B chromosomes in the 2 species have a common origin. The most parsimonious explanation would imply intergeneric hybridization in an ancestor of P. lineatus and P. nigricans yielding the B chromosome as a byproduct, which remained in these 2 species after their phylogenetic origin, but was perhaps lost in other Prochilodus species. This hypothesis predicts that B chromosomes are old genomic elements in this genus, and this could be tested once a species from a relative genus would be found showing homology of its A chromosomes with the B-probes employed here, through a comparison of B chromosome DNA sequences with those in the A chromosomes of this other species.

  10. Fish predation on a Daphnia hybrid species complex: A factor explaining species coexistence?

    NARCIS (Netherlands)

    Spaak, P.; Hoekstra, J.F.

    1997-01-01

    Recent studies on the life histories of Daphnia hybrids and their parental species have revealed that hybrids can combine an intermediate size with a relatively high reproductive rate, which might explain their success in many European lakes. Based on this information, we formulated the temporal

  11. Species-and tissue-specific mercury bioaccumulation in five fish species from Laizhou Bay in the Bohai Sea of China

    Institute of Scientific and Technical Information of China (English)

    LIU Jinhu; CAO Liang; HUANG Wei; DOU Shuozeng

    2013-01-01

    Mercury (Hg) concentrations in the tissues (muscle,stomach,liver,gills,skin,and gonads)of five fish species (mullet Liza haematocheilus,flathead fish Platycephalus indicus,sea bass Lateolabrax japonicus,mackerel Scomberomorus niphonius and silver pomfret Pampus argenteus) collected from Laizhou Bay in the Bohai Sea of China were investigated.The results indicate that Hg bioaccumulation in the five fish was tissue-specific,with the highest levels in the muscle and liver,followed by the stomach and gonads.The lowest levels were found in the gills and skin.Fish at higher trophic levels (flathead fish and sea bass) exhibited higher Hg concentrations than consumers at lower trophic levels.Mercury bioaccumulation tended to be positively correlated with fish length in mullet,silver pomfret,mackerel,and flathead fish,but was negatively correlated with fish length in sea bass.The Hg concentrations in the muscles of all fish species in Laizhou Bay were within the permissible limits of food safety set by national and international criteria.However,the suggesting maximum consumption of sea bass is 263 g per week for human health.

  12. Tolerance of native and non-native fish species to chemical stress: a case study for the River Rhine

    NARCIS (Netherlands)

    A. Fedorenkova; J.A. Vonk; A.M. Breure; A.J. Hendriks; R.S.E.W. Leuven

    2013-01-01

    Freshwater ecosystems can be impacted by invasive species. Non-native species can become invasive due to their high tolerance to environmental stressors (e.g., pollution and habitat modifications). Yet, tolerance of native and non-native fish species exposed simultaneously to multiple chemical stres

  13. Investigating photoreceptor densities, potential visual acuity, and cone mosaics of shallow water, temperate fish species.

    Science.gov (United States)

    Hunt, D E; Rawlinson, N J F; Thomas, G A; Cobcroft, J M

    2015-06-01

    The eye is an important sense organ for teleost species but can vary greatly depending on the adaption to the habitat, environment during ontogeny and developmental stage of the fish. The eye and retinal morphology of eight commonly caught trawl bycatch species were described: Lepidotrigla mulhalli; Lophonectes gallus; Platycephalus bassensis; Sillago flindersi; Neoplatycephalus richardsoni; Thamnaconus degeni; Parequula melbournensis; and Trachurus declivis. The cone densities ranged from 38 cones per 0.01 mm(2) for S. flindersi to 235 cones per 0.01 mm(2) for P. melbournensis. The rod densities ranged from 22800 cells per 0.01 mm(2) for L. mulhalli to 76634 cells per 0.01 mm(2) for T. declivis and potential visual acuity (based on anatomical measures) ranged from 0.08 in L. gallus to 0.31 in P. melbournensis. Higher rod densities were correlated with maximum habitat depths. Six species had the regular pattern of four double cones arranged around a single cone in the photoreceptor mosaic, while T. declivis had only rows of double cones. P. melbournensis had the greatest potential ability for detecting fine detail based on eye anatomy. The potential visual acuity estimates and rod densities can be applied to suggest the relative detection ability of different species in a commercial fishing context, since vision is a critical sense in an illuminated environment for perceiving an oncoming trawl.

  14. Segregation of Species-Specific Male Attractiveness in F2 Hybrid Lake Malawi Cichlid Fish

    Directory of Open Access Journals (Sweden)

    Ola Svensson

    2011-01-01

    Full Text Available Among the huge radiations of haplochromine cichlid fish in Lakes Malawi and Victoria, closely related species are often reproductively isolated via female mate choice although viable fertile hybrids can be produced when females are confined only with heterospecific males. We generated F2 hybrid males from a cross between a pair of closely related sympatric cichlid fish from Lake Malawi. Laboratory mate choice experiments using microsatellite paternity analysis demonstrated that F2 hybrid males differed significantly in their attractiveness to females of the two parental species, indicating heritable variation in traits involved in mate choice that may contribute to reproductive isolation between these species. We found no significant correlation between male mating success and any measurement of male colour pattern. A simple quantitative genetic model of reproductive isolation suggests that there may be as few as two chromosomal regions controlling species-specific attractiveness. We propose that adaptive radiation of Lake Malawi cichlids could be facilitated by the presence of genes with major effects on mate choice and reproductive isolation.

  15. Gastrointestinal Helminth Parasites Community of Fish Species in a Niger Delta Tidal Creek, Nigeria

    Directory of Open Access Journals (Sweden)

    Anthony Ekata Ogbeibu

    2014-01-01

    Full Text Available A pool of fish species in a Niger Delta tidal creek, Buguma Creek, Nigeria, collected monthly from November 2004 to June 2006, at flood tides, were examined for gastrointestinal helminth parasites. The fish species were caught with hooks and lines and cast nets. Only nematode parasites were encountered in the study. Of the 1,149 fish specimens examined, 213 (representing 18.5% were infected with various nematodes parasites. Dasyatis margarita had the highest prevalence rate of 66.7% (2 infected out of 3 examined, followed by Pseudotolithus (Pseudotolithus senegalensis with a prevalence of 41.7% (10 infected out of 24, while the least infected were Arius gigas and Pomadasys jubelini with prevalence of 3.8% and 1.4%, respectively. No infection was recorded in Elops lacerta, Gobius sp., Lutjanus agennes, L. goreensis, Argyrosomus regius, Sphyraena guachancho, S. sphyraena, Cynoglossus senegalensis, Sarotherodon melanotheron, Tilapia guineensis, Liza falcipinnis, Mugil cephalus, and M. curema. The nematode parasites, Capillaria zederi, and Aplectana hamatospicula had the highest prevalence of 33.3% in D. margarita. Laurotravassoxyuris sp. also had the same prevalence in Trichiurus lepturus. Goezia sigalasi had the second highest prevalence of 12.5% in P. (Fonticulus elongatus which had the highest number examined, due to its high dominance in the water.

  16. Valorization of By-Products from Commercial Fish Species: Extraction and Chemical Properties of Skin Gelatins.

    Science.gov (United States)

    Sousa, Sérgio C; Vázquez, José A; Pérez-Martín, Ricardo I; Carvalho, Ana P; Gomes, Ana M

    2017-09-14

    Fish skins constitute an important fraction of the enormous amount of wastes produced by the fish processing industry, part of which may be valorized through the extraction of gelatins. This research exploited the extraction and characterization of gelatins from the skin of three seawater fish species, namely yellowfin tuna (Thunnus albacares), blue shark (Prionace glauca), and greenland halibut (Reinhardtius hippoglossoides). Characterization included chemical composition, rheology, structure, texture, and molecular weight, whereas extraction studies intended to reduce costly steps during extraction process (reagents concentration, water consumption, and time of processing), while maintaining extraction efficiency. Chemical and physical characterization of the obtained gelatins revealed that the species from which the gelatin was extracted, as well as the heat treatment used, were key parameters in order to obtain a final product with specific properties. Therefore, the extraction conditions selected during gelatin production will drive its utilization into markets with well-defined specifications, where the necessity of unique products is being claimed. Such achievements are of utmost importance to the food industry, by paving the way to the introduction in the market of gelatins with distinct rheological and textural properties, which enables them to enlarge their range of applications.

  17. Effects of the synthetic pyrethroid insecticide, permethrin, on two estuarine fish species.

    Science.gov (United States)

    Parent, Lindsey M; Delorenzo, Marie E; Fulton, Michael H

    2011-01-01

    Limited toxicity data are available for estuarine and marine species and the widely used pyrethroid insecticide, permethrin. This study determined acute effects of permethrin on survival, lipid peroxidation, acetylcholinesterase activity, and splenocyte proliferation for two fish species found in South Carolina estuaries; juvenile red drum (Sciaenops ocellatus) and adult mummichog (Fundulus heteroclitus). Juvenile S. ocellatus were significantly more sensitive than adult F. heteroclitus to permethrin exposure, with a 96-h LC50 value of 8 μg/L determined for red drum compared to 23 μg/L for mummichog. Lipid peroxidation activity of the liver increased in permethrin-treated fish compared to control animals after 24 h and decreased after 96 h. Permethrin had no effect on acetylcholinesterase activity of the brain at the concentrations tested. Permethrin exposure significantly inhibited splenocyte proliferation, indicating an immunosuppressive effect. Most of the effects of permethrin on fish cellular stress enzymes and survival occurred at concentrations much higher than those typically measured in the environment. However, inhibition of splenocyte proliferation in juvenile red drum occurred at approximately twice that of measured permethrin concentrations in surface water. These findings may prove useful to the future management and regulation of pyrethroid insecticide use near estuarine habitats.

  18. Antimicrobial Activity of Various Plant Extracts on Pseudomonas Species Associated with Spoilage of Chilled Fish

    Directory of Open Access Journals (Sweden)

    Osan Bahurmiz

    2016-11-01

    Full Text Available The antimicrobial activity of various plant extracts on Pseudomonas bacteria isolated from spoiled chilled tilapia (Oreochromis sp. was evaluated in this study. In the first stage of this study, red tilapia was subjected to chilled storage (4°C for 3 weeks, and spoilage bacteria were isolated and identified from the spoiled fish. Pseudomonas was the dominant bacteria isolated from the spoiled fish and further identification revealed that P. putida, P. fluorescens and Pseudomonas spp. were the main species of this group. In the second stage, methanolic extracts of 15 selected plant species were screened for their antimicrobial activity, by agar disc diffusion method, against the Pseudomonas isolates. Results indicated that most of the extracts had different degrees of activity against the bacterial isolates. The strongest activity was exhibited by bottlebrush flower (Callistemon viminalis extract. This was followed by extracts from guava bark (Psidium guajava and henna leaf (Lawsonia inermis. Moderate antimicrobial activities were observed in extracts of clove (Syzygium aromaticum, leaf and peel of tamarind (Tamarindus indica, cinnamon bark (Cinnamomum zeylanicum, wild betel leaf (Piper sarmentosum and fresh thyme (Thymus spp.. Weak or no antimicrobial activity was observed from the remaining extracts. The potential antimicrobial activity shown by some plant extracts in this study could significantly contribute to the fish preservation.

  19. Elucidating the diversity of aquatic microdochium and trichoderma species and their activity against the fish pathogen Saprolegnia diclina

    NARCIS (Netherlands)

    Liu, Yiying; Zachow, Christin; Raaijmakers, J.M.; Bruijn, De Irene

    2016-01-01

    Animals and plants are increasingly threatened by emerging fungal and oomycete diseases. Amongst oomycetes, Saprolegnia species cause population declines in aquatic animals, especially fish and amphibians, resulting in significant perturbation in biodiversity, ecological balance and food security

  20. Elucidating the diversity of aquatic microdochium and trichoderma species and their activity against the fish pathogen Saprolegnia diclina

    NARCIS (Netherlands)

    Liu, Yiying; Zachow, Christin; Raaijmakers, J.M.; Bruijn, De Irene

    2016-01-01

    Animals and plants are increasingly threatened by emerging fungal and oomycete diseases. Amongst oomycetes, Saprolegnia species cause population declines in aquatic animals, especially fish and amphibians, resulting in significant perturbation in biodiversity, ecological balance and food

  1. Elucidating the diversity of aquatic Microdochium and Trichoderma species and their activity against the fish pathogen Saprolegnia diclina

    NARCIS (Netherlands)

    Liu, Yiying; Zachow, Christin; Raaijmakers, J.M.; De Bruijn, I.

    2016-01-01

    Animals and plants are increasingly threatened by emerging fungal and oomycete diseases. Amongst oomycetes, Saprolegnia species cause population declines in aquatic animals, especially fish and amphibians, resulting in significant perturbation in biodiversity, ecological balance and food security.

  2. Coral reef fish species survey data GIS from the Florida Keys National Marine Sanctuary (NODC Accession 0001394)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of an ArcView shapefile set that contains locations of sampled coral reef fish species at the National Marine Sanctuary along the Florida...

  3. Mixed function oxidase dependent biotransformation of polychlorinated biphenyls by different species of fish from the North Sea

    DEFF Research Database (Denmark)

    Mehrtens, G.; Laturnus, F.

    1999-01-01

    Mixed function oxidase (MFO) dependent biotransformation of polychlorinated biphenyls (PCBs) was measured in three different fish species from the North Sea. Liver microsomes of plaice (Pleuronectes platessa), dab (Limanda limanda) and cod (Gadus morhua) were isolated and incubated with different...

  4. Microsomal EROD data of fish liver sample assay from species collected in the Salt and Gila Rivers, Arizona

    Science.gov (United States)

    Nicks, Diane

    2017-01-01

    This dataset includes microsomal ERDO data from an assay done with liver samples from several fish species that are found in Arizona at sites that are being assessed for PBDE contamination. The data was created in September and October 2016.

  5. Experiment on an Integrated Ricefish Polyculture System (6 Species, 1- 2 fish/m2 in the Mekong Delta

    Directory of Open Access Journals (Sweden)

    Lan, LM.

    2002-01-01

    Full Text Available Our ricefish polyculture (6 species results at two stocking densities (1 and 2 fish/m2 show that: The water quality in a ricefish polyculture system, such as water temperature (29.1 – 29.0 °C, water pH (6.6 – 6.7, water transparency (18.0 – 20.8 cm, dissolved O2 (4.7 – 4.6 ppm, CO2 (22.8 – 23.1 ppm, COD (11.9 – 12.7 ppm, are similar at both densities and acceptable for the 6 tropical fish species. Ammonium and phosphorus concentrations are statistically higher at 1 fish/m2 (0.4 and 0.2 ppm. The primary productivity is similar for both densities (6.5 – 6.8 g O2/m3/day and suitable for fish culture. The phytoplankton biodiversity is relatively high and at the same level for both treatments (74 – 63 taxa, but the densities of phytoplankton, of zooplankton, and the biomass of zoobenthos are lower at the highest density (2 fish/m2, probably due to a higher predation by fish.The fish yield (808 kg/ha at 2 fish/m2 is higher than at 1 fish/m2 (482 kg/ha. The cost ratio benefit (1.84 and the cost ratio profit (1.81 for farm households at 1 fish/m2 are lower than those values at 2 fish/m2 (2.1 and 2.05 respectively. Regarding the aquaculture extension program, the model of the ricefish polyculture (6 species system with the stocking density of 2 fish/m2 could be extended in the rice fields to improve farmer's income in the Mekong delta.

  6. The sialate O-acetylesterase EstA from gut Bacteroidetes species enables sialidase-mediated cross-species foraging of 9-O-acetylated sialoglycans

    Science.gov (United States)

    Robinson, Lloyd S.; Lewis, Warren G.

    2017-01-01

    The gut harbors many symbiotic, commensal, and pathogenic microbes that break down and metabolize host carbohydrates. Sialic acids are prominent outermost carbohydrates on host glycoproteins called mucins and protect underlying glycan chains from enzymatic degradation. Sialidases produced by some members of the colonic microbiota can promote the expansion of several potential pathogens (e.g. Clostridium difficile, Salmonella, and Escherichia coli) that do not produce sialidases. O-Acetyl ester modifications of sialic acids help resist the action of many sialidases and are present at high levels in the mammalian colon. However, some gut bacteria, in turn, produce sialylate-O-acetylesterases to remove them. Here, we investigated O-acetyl ester removal and sialic acid degradation by Bacteroidetes sialate-O-acetylesterases and sialidases, respectively, and subsequent utilization of host sialic acids by both commensal and pathogenic E. coli strains. In vitro foraging studies demonstrated that sialidase-dependent E. coli growth on mucin is enabled by Bacteroides EstA, a sialate O-acetylesterase acting on glycosidically linked sialylate-O-acetylesterase substrates, particularly at neutral pH. Biochemical studies suggested that spontaneous migration of O-acetyl esters on the sialic acid side chain, which can occur at colonic pH, may serve as a switch controlling EstA-assisted sialic acid liberation. Specifically, EstA did not act on O-acetyl esters in their initial 7-position. However, following migration to the 9-position, glycans with O-acetyl esters became susceptible to the sequential actions of bacterial esterases and sialidases. We conclude that EstA specifically unlocks the nutritive potential of 9-O-acetylated mucus sialic acids for foraging by bacteria that otherwise are prevented from accessing this carbon source. PMID:28526748

  7. The sialate O-acetylesterase EstA from gut Bacteroidetes species enables sialidase-mediated cross-species foraging of 9-O-acetylated sialoglycans.

    Science.gov (United States)

    Robinson, Lloyd S; Lewis, Warren G; Lewis, Amanda L

    2017-07-14

    The gut harbors many symbiotic, commensal, and pathogenic microbes that break down and metabolize host carbohydrates. Sialic acids are prominent outermost carbohydrates on host glycoproteins called mucins and protect underlying glycan chains from enzymatic degradation. Sialidases produced by some members of the colonic microbiota can promote the expansion of several potential pathogens (e.g. Clostridium difficile, Salmonella, and Escherichia coli) that do not produce sialidases. O-Acetyl ester modifications of sialic acids help resist the action of many sialidases and are present at high levels in the mammalian colon. However, some gut bacteria, in turn, produce sialylate-O-acetylesterases to remove them. Here, we investigated O-acetyl ester removal and sialic acid degradation by Bacteroidetes sialate-O-acetylesterases and sialidases, respectively, and subsequent utilization of host sialic acids by both commensal and pathogenic E. coli strains. In vitro foraging studies demonstrated that sialidase-dependent E. coli growth on mucin is enabled by Bacteroides EstA, a sialate O-acetylesterase acting on glycosidically linked sialylate-O-acetylesterase substrates, particularly at neutral pH. Biochemical studies suggested that spontaneous migration of O-acetyl esters on the sialic acid side chain, which can occur at colonic pH, may serve as a switch controlling EstA-assisted sialic acid liberation. Specifically, EstA did not act on O-acetyl esters in their initial 7-position. However, following migration to the 9-position, glycans with O-acetyl esters became susceptible to the sequential actions of bacterial esterases and sialidases. We conclude that EstA specifically unlocks the nutritive potential of 9-O-acetylated mucus sialic acids for foraging by bacteria that otherwise are prevented from accessing this carbon source. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. DNA BARCODING OF FISH SPECIES FROM THE MEDITERRANEAN COAST OF ISRAEL

    Directory of Open Access Journals (Sweden)

    A. SHIRAK

    2014-06-01

    Full Text Available Accurately-classified genomic data in the Barcode of Life Data System (BOLD database is vital to the protection and conservation of marine biodiversity in the Mediterranean Sea. The taxonomic classifications of 468 fish of 50 Mediterranean species were analyzed using the BOLD Identifier tool for variation in the cytochrome oxidase subunit I (COI mitochondrial gene. Within species, nucleotide maximum composite likelihood was low with a mean of 0.0044±0.0008. Three presumptive species had significantly higher values e.g., Arnoglossus spp. (0.07, Torquigener flavimaculosus (0.013 and Boops boops (0.028. However, samples of Arnoglossus species were sub-classified into two groups that were finally identified as two different species e.g., Arnoglossus laterna and Arnoglossus thori. For the different species, BLAST searches against the BOLD database using our DNA barcoding data as the query sequences designated the most similar targets into groups. For each analyzed species, the similarity of the first and second threshold groups ranged from 95 to 99% and from 83 to 98%, respectively. Sequence based classification for the first threshold group was concordant with morphology-based identification. However, for 34 analyzed species (68% overlaps of species between the two threshold groups hampered classification. Tree-based phylogeny analysis detected more than one cluster in the first threshold group for 22 out of 50 species, representing genetic subgroups and geographic origins. There was a tendency for higher conservation and lower number of clusters in the Lessepsian (Red Sea migrant versus indigenous species.

  9. Prey selection by two benthic fish species in a Mato Grosso stream, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Carla Ferreira Rezende

    2011-12-01

    Full Text Available Key to understand predator choice is the relationship between predator and prey abundance. There are few studies related to prey selection and availability. Such an approach is still current, because the ability to predict aspects of the diet in response to changes in prey availability is one of the major problems of trophic ecology. The general objective of this study was to evaluate prey selection by two species (Characidium cf. vidali and Pimelodella lateristriga of the Mato Grosso stream, in Saquarema, Rio de Janeiro, Brazil. Benthos and fishes were collected in June, July and September of 2006 and January and February of 2007. Fish were collected with electric fishing techniques and benthos with a surber net. Densities of benthic organisms were expressed as the number of individuals per/m2. After sampling, the invertebrates were fixed in 90% ethanol, and, in the laboratory, were identified to the lowest taxonomical level. Approximately, seventy individuals from each species were selected randomly in each month. Fishes were fixed in 10% formalin in the field and transferred to 70o GL ethanol in the laboratory. Fishes had their stomachs removed for subsequent analysis. Fish diet was described according to the numeric frequency method. The Manly Electivity I ndex was applied in order to verify prey selection. The most abundant families in both benthos and diet of both fish species were the same, indicating that these species consume mainly most abundant prey in the environment. We concluded that prey selection occurs even for preys that had small abundance in the environment . However, it is the availability of the macroinvertebrate resources that determines the major composition of items in diet of fish, demonstrating that the abundance is the factor that most influences the choice of prey. Rev. Biol. Trop. 59 (4: 1697-1706. Epub 2011 December 01.Existen muy pocos estudios relacionados con la selección y disponibilidad de las presas por

  10. FAST Real Time PCR for control of intra-species recycling in aquaculture feed, focused to the most relevant fish species farmed in Europe.

    Science.gov (United States)

    Espiñeira, Montserrat; Vieites, Juan M

    2016-08-01

    Recent regulations in animal feed composition prohibit intra-species recycling, the recycling of one given animal species to the same species, in order to avoid potential safety risks to human and animal health. These regulations have generated the need of their control in aquaculture by effective and specific analytical techniques. To date, most studies of species identification and detection in feedstuffs are focused on land species, but few studies are focused on species composition in fish feed. The present work describes five methodologies based in Real Time PCR for detection of the most relevant fish species farmed in Europe: gilthead sea bream (Sparus aurata); sea bass (Dicentrarchus labrax); turbot (Scophthalmus maximus); rainbow trout (Onchorynchus mykiss); and salmon (Salmo salar), in order to guarantee the intra-species recycling regulation in aquaculture feedstuffs.

  11. Hypermethylated Chromosome Regions in Nine Fish Species with Heteromorphic Sex Chromosomes.

    Science.gov (United States)

    Schmid, Michael; Steinlein, Claus; Yano, Cassia F; Cioffi, Marcelo B

    2015-01-01

    Sites and amounts of 5-methylcytosine (5-MeC)-rich chromosome regions were detected in the karyotypes of 9 Brazilian species of Characiformes fishes by indirect immunofluorescence using a monoclonal anti-5-MeC antibody. These species, belonging to the genera Leporinus, Triportheus and Hoplias, are characterized by highly differentiated and heteromorphic ZW and XY sex chromosomes. In all species, the hypermethylated regions are confined to constitutive heterochromatin. The number and chromosome locations of hypermethylated heterochromatic regions in the karyotypes are constant and species-specific. Generally, heterochromatic regions that are darkly stained by the C-banding technique are distinctly hypermethylated, but several of the brightly fluorescing hypermethylated regions merely exhibit moderate or faint C-banding. The ZW and XY sex chromosomes of all 9 analyzed species also show species-specific heterochromatin hypermethylation patterns. The analysis of 5-MeC-rich chromosome regions contributes valuable data for comparative cytogenetics of closely related species and highlights the dynamic process of differentiation operating in the repetitive DNA fraction of sex chromosomes.

  12. Flat and complex temperate reefs provide similar support for fish: Evidence for a unimodal species-habitat relationship.

    Science.gov (United States)

    Paxton, Avery B; Pickering, Emily A; Adler, Alyssa M; Taylor, J Christopher; Peterson, Charles H

    2017-01-01

    Structural complexity, a form of habitat heterogeneity, influences the structure and function of ecological communities, generally supporting increased species density, richness, and diversity. Recent research, however, suggests the most complex habitats may not harbor the highest density of individuals and number of species, especially in areas with elevated human influence. Understanding nuances in relationships between habitat heterogeneity and ecological communities is warranted to guide habitat-focused conservation and management efforts. We conducted fish and structural habitat surveys of thirty warm-temperate reefs on the southeastern US continental shelf to quantify how structural complexity influences fish communities. We found that intermediate complexity maximizes fish abundance on natural and artificial reefs, as well as species richness on natural reefs, challenging the current paradigm that abundance and other fish community metrics increase with increasing complexity. Naturally occurring rocky reefs of flat and complex morphologies supported equivalent abundance, biomass, species richness, and community composition of fishes. For flat and complex morphologies of rocky reefs to receive equal consideration as essential fish habitat (EFH), special attention should be given to detecting pavement type rocky reefs because their ephemeral nature makes them difficult to detect with typical seafloor mapping methods. Artificial reefs of intermediate complexity also maximized fish abundance, but human-made structures composed of low-lying concrete and metal ships differed in community types, with less complex, concrete structures supporting lower numbers of fishes classified largely as demersal species and metal ships protruding into the water column harboring higher numbers of fishes, including more pelagic species. Results of this study are essential to the process of evaluating habitat function provided by different types and shapes of reefs on the seafloor

  13. Modeling the Relations Between Flow Regime Components, Species Traits, and Spawning Success of Fishes in Warmwater Streams

    Science.gov (United States)

    Craven, Scott W.; Peterson, James T.; Freeman, Mary C.; Kwak, Thomas J.; Irwin, Elise

    2010-08-01

    Modifications to stream hydrologic regimes can have a profound influence on the dynamics of their fish populations. Using hierarchical linear models, we examined the relations between flow regime and young-of-year fish density using fish sampling and discharge data from three different warmwater streams in Illinois, Alabama, and Georgia. We used an information theoretic approach to evaluate the relative support for models describing hypothesized influences of five flow regime components representing: short-term high and low flows; short-term flow stability; and long-term mean flows and flow stability on fish reproductive success during fish spawning and rearing periods. We also evaluated the influence of ten fish species traits on fish reproductive success. Species traits included spawning duration, reproductive strategy, egg incubation rate, swimming locomotion morphology, general habitat preference, and food habits. Model selection results indicated that young-of-year fish density was positively related to short-term high flows during the spawning period and negatively related to flow variability during the rearing period. However, the effect of the flow regime components varied substantially among species, but was related to species traits. The effect of short-term high flows on the reproductive success was lower for species that broadcast their eggs during spawning. Species with cruiser swimming locomotion morphologies (e.g., Micropterus) also were more vulnerable to variable flows during the rearing period. Our models provide insight into the conditions and timing of flows that influence the reproductive success of warmwater stream fishes and may guide decisions related to stream regulation and management.

  14. Different phylogenomic approaches to resolve the evolutionary relationships among model fish species.

    Science.gov (United States)

    Negrisolo, Enrico; Kuhl, Heiner; Forcato, Claudio; Vitulo, Nicola; Reinhardt, Richard; Patarnello, Tomaso; Bargelloni, Luca

    2010-12-01

    Comparative genomics holds the promise to magnify the information obtained from individual genome sequencing projects, revealing common features conserved across genomes and identifying lineage-specific characteristics. To implement such a comparative approach, a robust phylogenetic framework is required to accurately reconstruct evolution at the genome level. Among vertebrate taxa, teleosts represent the second best characterized group, with high-quality draft genome sequences for five model species (Danio rerio, Gasterosteus aculeatus, Oryzias latipes, Takifugu rubripes, and Tetraodon nigroviridis), and several others are in the finishing lane. However, the relationships among the acanthomorph teleost model fishes remain an unresolved taxonomic issue. Here, a genomic region spanning over 1.2 million base pairs was sequenced in the teleost fish Dicentrarchus labrax. Together with genomic data available for the above fish models, the new sequence was used to identify unique orthologous genomic regions shared across all target taxa. Different strategies were applied to produce robust multiple gene and genomic alignments spanning from 11,802 to 186,474 amino acid/nucleotide positions. Ten data sets were analyzed according to Bayesian inference, maximum likelihood, maximum parsimony, and neighbor joining methods. Extensive analyses were performed to explore the influence of several factors (e.g., alignment methodology, substitution model, data set partitions, and long-branch attraction) on the tree topology. Although a general consensus was observed for a closer relationship between G. aculeatus (Gasterosteidae) and Di. labrax (Moronidae) with the atherinomorph O. latipes (Beloniformes) sister taxon of this clade, with the tetraodontiform group Ta. rubripes and Te. nigroviridis (Tetraodontiformes) representing a more distantly related taxon among acanthomorph model fish species, conflicting results were obtained between data sets and methods, especially with respect

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

    Directory of Open Access Journals (Sweden)

    Esteban A. Agudo-Adriani

    2016-04-01

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

  16. ABUNDANCE AND BIOMASS ESTIMATES OF COMMERCIAL FISH SPECIES USING HYDRO-ACOUSTIC METHOD IN JAKARTA BAY, INDONESIA

    Directory of Open Access Journals (Sweden)

    Andria Ansri Utama

    2015-06-01

    Full Text Available The Jakarta Bay is known as a fishing ground area for several traditional types of fishing gears. The fishery has important role to provide nutrition, sustainable livelihoods, and poverty alleviation around the area. Abundance estimation of commercial fish species in the Jakarta Bay is essential particularly comparable of series data in order to evaluate the potential changes in distribution and abundance. The purpose of this study is analyzing the distribution of commercial fish species in the Jakarta Bay and estimate their abundance and biomass. Fish assemblages were concentrated in the eastern and central part of bay. Apparently salinity and DO associated with rich density of phytoplankton and zooplankton may explain the spatial variability of short-bodied mackerel and pony fish, while assemblages pattern of spiny hairtail and croaker might be driven by the availability of small planktivorous fish as their diet. The most abundant commercial fish in the Jakarta Bay are Short-bodied mackerel (Rastrelliger brachysoma, Ponyfish (Leiognathus sp., Croaker (Johnius sp. dan Spiny hairtail (Lepturacanthus savala respectively. Furthermore, biomass estimates for those species showed short-bodied mackerel has the highest biomass followed by spiny hairtail, croaker, and ponyfish.

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

    Science.gov (United States)

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

    2016-01-01

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

  18. Experimental infection of six North American fish species with the North Carolina strain of spring Viremia of Carp Virus

    Science.gov (United States)

    Emmenegger, Eveline J.; Sanders, George E.; Conway, Carla M.; Binkowski, Fred P.; Winton, James R.; Kurath, Gael

    2016-01-01

    Spring viremia of carp virus (SVCV) is a rhabdoviral pathogen associated with disease outbreaks in cultured and wild fish worldwide. Common carp (Cyprinus carpio carp), and koi (C. carpio koi) suffer the highest mortalities from SVCV infections, while other cyprinid fish species have varying susceptibility. Although salmonid fish typically are considered refractory to infection by SVCV, there have been a few reports suggesting infection has occurred in rainbow trout (Oncorhynchus mykiss). There have been no reports of Percid fish being infected with SVCV. Since the first North American outbreak of SVCV at a North Carolina koi farm in 2002 there have been eight subsequent detections or outbreaks of SVCV among fish species from the families of Cyprinidae andCentrarchidae within the US and Canada. Thus, this exotic virus is considered a potential threat to native and cultured fish populations in North America. We performed multiple experimental challenges with fish species from three families (Salmonidae, Cyprinidae, and Percidae) to identify the potential risk associated with SVCV exposure of resident fish populations in North America.

  19. Distribution and bioaccumulation of steroidal and phenolic endocrine disrupting chemicals in wild fish species from Dianchi Lake, China

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jingliang; Wang Renmin; Huang Bin; Lin Chan; Wang Yu [Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China); Pan Xuejun, E-mail: xjpan@kmust.edu.cn [Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China)

    2011-10-15

    The distribution and bioaccumulation of steroidal and phenolic endocrine disrupting chemicals (EDCs) were studied in various tissues of wild fish species from Dianchi Lake, China. In muscle tissue, 4-tert-octylphenol, 4-cumylphenol, 4-nonlyphenol and bisphenol A were detected in fish from each sampling site, with maximal concentrations of 4.6, 4.4, 18.9 and 83.5 ng/g dry weight (dw), respectively. Steroids (estrone, 17{beta}-estradiol 17{alpha}-ethynylestradiol and estriol) were found at lower levels (<11.3 ng/g dw) and less frequently in muscle samples. The highest concentrations of steroids and phenols were found in liver, followed by those in gill and the lowest concentration was found in muscle. The field bioconcentration factors (BCFs) of phenols were calculated in fish species ranged from 18 to 97. Moreover, the measured tissue concentrations were utilized in order to estimate water concentration of steroids (4.4-18.0 ng/L). These results showed that steroidal and phenolic EDCs were likely ubiquitous contaminants in wild fish. - Highlights: > We assess the occurrence of EDCs in wild fish from Dianchi Lake, China. > We investigate the distribution of steroidal and phenolic EDCs in fish tissues. > We estimate the bioaccumulation of wild fish to steroidal and phenolic EDCs. > Steroidal and phenolic EDCs are likely ubiquitous contaminants in wild fish. - Contaminants of endocrine disrupting chemicals in wild fish.

  20. Consumptive effects of fish reduce wetland crayfish recruitment and drive species turnover.

    Science.gov (United States)

    Kellogg, Christopher M; Dorn, Nathan J

    2012-04-01

    Predators and dry-disturbances have pronounced effects on invertebrate communities and can deterministically affect compositional turnover between discrete aquatic habitats. We examined the effect of sunfish (Lepomis spp.) predators on two native crayfish, Procambarus alleni and P. fallax, that regionally coexist in an expansive connected wetland in order to test the hypotheses that sunfish predation limits crayfish recruitment (both species) and that it disproportionately affects P. alleni, the species inhabiting temporary wetlands. In replicate vegetated wetlands (18.6 m(2)), we quantified summertime crayfish recruitment and species compositio