Science.gov

Sample records for freshwater fish gambusia

  1. Ecotoxicological effect of zinc pyrithione in the freshwater fish Gambusia holbrooki.

    PubMed

    Nunes, B; Braga, M R; Campos, J C; Gomes, R; Ramos, A S; Antunes, S C; Correia, A T

    2015-11-01

    Currently diverse biocidal agents can be used for distinct applications, such as personal hygiene, disinfection, antiparasitic activity, and antifouling effects. Zinc pyrithione is an organometallic biocide, with bactericidal, algicidal and fungicidal activities. It has been recently incorporated in antifouling formulas, such as paints, which prevent the establishment of a biofilm on surfaces exposed to the aquatic environment. It has also been used in cosmetics, such as anti-dandruff shampoos and soaps. Previously reported data has shown the presence of this substance in the aquatic compartment, a factor contributing to the potential exertion of toxic effects, and there is also evidence that photodegradation products of zinc pyrithione were involved in neurotoxic effects, namely by inhibiting cholinesterases in fish species. Additional evidence points to the involvement of zinc pyrithione in alterations of metal homeostasis and oxidative stress, in both aquatic organisms and human cell models. The present work assesses the potential ecotoxicity elicited by zinc pyrithione in the freshwater fish Gambusia holbrooki after an acute (96 h) exposure. The oxidative stress was assessed by the quantification of the activities of specific enzymes from the antioxidant defense system, such as catalase, and glutathione-S-transferases; and the extent of peroxidative damage was quantified by measuring the thiobarbituric acid reactive substances levels. Neurotoxicity was assessed through measurement of acetylcholinesterase activity; and a standardized method for the description and assessment of histological changes in liver and gills of was also used. Zinc pyrithione caused non-specific and reversible tissue alterations, both in liver and gills of exposed organisms. However, histopathological indices were not significantly different from the control group. In terms of oxidative stress biomarkers, none of the tested biomarkers indicated the occurrence of pro-oxidative effects

  2. Digestive enzymes of two freshwater fishes (Limia vittata and Gambusia punctata) with different dietary preferences at three developmental stages.

    PubMed

    Falcón-Hidalgo, Banessa; Forrellat-Barrios, Alina; Carrillo Farnés, Olimpia; Ubieta Hernández, Kenia

    2011-02-01

    The variation of activity of some digestive enzymes was studied in three age groups of two freshwater endemic fishes from Cuba: Limia vittata and Gambusia punctata. Trypsin, chymotrypsin and amylase activities showed a different pattern between both species. Trypsin and chymotrypsin activity increased with the age of fishes, while amylase activity decreased. The highest activity of trypsin and chymotrypsin was registered in G. punctata while the highest amylase activity was detected in L. vittata. Zymograms revealed proteases with molecular masses similar to trypsin and chymotrypsin reported for other fish species. Amylase electrophoresis showed the presence of this enzyme; in L. vittata amylase zymograms showed two bands with molecular masses of 175 and 100 kDa and in G. punctata four bands of 175, 100, 46 and 30 kDa respectively were found. The activity of the digestive enzymes can be used as an effective indicator of the feeding habits and the development of the digestive tracts in L. vittata and G. punctata. PMID:21044696

  3. Acute effects of tetracycline exposure in the freshwater fish Gambusia holbrooki: antioxidant effects, neurotoxicity and histological alterations.

    PubMed

    Nunes, B; Antunes, S C; Gomes, R; Campos, J C; Braga, M R; Ramos, A S; Correia, A T

    2015-02-01

    A large body of evidence was compiled in the recent decades showing a noteworthy increase in the detection of pharmaceutical drugs in aquatic ecosystems. Due to its ubiquitous presence, chemical nature, and practical purpose, this type of contaminant can exert toxic effects in nontarget organisms. Exposure to pharmaceutical drugs can result in adaptive alterations, such as changes in tissues, or in key homeostatic mechanisms, such as antioxidant mechanisms, biochemical/physiological pathways, and cellular damage. These alterations can be monitored to determine the impact of these compounds on exposed aquatic organisms. Among pharmaceutical drugs in the environment, antibiotics are particularly important because they include a variety of substances widely used in medical and veterinary practice, livestock production, and aquaculture. This wide use constitutes a decisive factor contributing for their frequent detection in the aquatic environment. Tetracyclines are the individual antibiotic subclass with the second highest frequency of detection in environmental matrices. The characterization of the potential ecotoxicological effects of tetracycline is a much-required task; to attain this objective, the present study assessed the acute toxic effects of tetracycline in the freshwater fish species Gambusia holbrooki by the determination of histological changes in the gills and liver, changes in antioxidant defense [glutathione S-transferase (GST), catalase (CAT), and lipoperoxidative damage] as well as potential neurotoxicity (acetylcholinesterase activity). The obtained results suggest the existence of a cause-and-effect relationship between the exposure to tetracycline and histological alterations (more specifically in gills) and enzymatic activity (particularly the enzyme CAT in liver and GST in gills) indicating that this compound can exert a pro-oxidative activity. PMID:25475590

  4. Development of critical life stage assays: Teratogenic effects of SRS effluent components on freshwater fish, gambusia

    SciTech Connect

    Guram, M.S.

    1990-11-01

    The final report of the research carried out at Voorhees College contains a composite compilation of the last two years work. The data note variation in the number of young fish delivered per female vary markedly between several ponds on the SRS and of SRS ponds. The reasons for this are unknown at present. Initial research was carried out on the effects on the developing fish fetus of various substances that may have produced these variations. Further study is necessary to identify the factors that produce the observed alterations. 7 figs., 5 tabs.

  5. Development of critical life stage assays: Teratogenic effects of ash basin effluent components on freshwater fish, Gambusia affinis and Daphnia: Progress report, May 21, 1987-- June 1, 1988

    SciTech Connect

    Guram, M.S.; Boatwright, B.

    1988-04-06

    The Voorhees College research project directed toward describing and evaluating the reproductive activity of a representative fish species (Gambusia) in several ponds on the SRP property has established several important points during the first phase (year I) of its operation. It has been demonstrated that significant numbers of the selected fish can be obtained from each of the test ponds, and can be returned to the Voorhees College laboratories in good physiological condition. This is shown by very minimal loss of fish during and following capture, transportation, and subsequent placement in individual tanks for rearing young when delivered during subsequent weeks. Forty individual fry rearing tanks are now functioning with capture of fry being carried out as they are delivered by each female fish. Preservation of fry is made in Bouins solution for detailed analysis of any abnormalities. The goal of the first phase is to establish a year long (several seasons) profile of the number of fry delivered per female fish, presence or absence of abnormal fry at birth, variation in fry between successive deliveries of fry, variations throughout the year, and variations of fry characteristics between the several ponds from which the adult female fish were obtained. Excellent technical help has been obtained from Voorhees College senior biology major students. These students have maintained the health of the rearing ranks throughout the study period, have collected the fry as they are born, and analyzed data obtained in observations on those fry.

  6. Mosquitofish (Gambusia affinis) responds differentially to a robotic fish of varying swimming depth and aspect ratio.

    PubMed

    Polverino, Giovanni; Porfiri, Maurizio

    2013-08-01

    In this study, we explore the feasibility of using bioinspired robotics to influence the behaviour of mosquitofish (Gambusia affinis), a social freshwater fish species that is extensively studied for the ecological issues associated with its diffusion in non-native environments. Specifically, in a dichotomous choice test, we investigate the behavioural response of small shoals of mosquitofish to a robotic fish inspired by mosquitofish in its colouration, shape, aspect ratio, and locomotion. Our results indicate that the swimming depth and the aspect ratio of the robotic fish are both determinants of mosquitofish preference. In particular, we find that mosquitofish are never attracted by a robotic fish whose colouration and shape are inspired by live subjects and that the degree of repulsion varies as a function of the swimming depth and the aspect ratio. PMID:23684918

  7. Mercury bio-concentration factor in mosquito fish (Gambusia spp.) in the Florida Everglades.

    PubMed

    Julian, Paul

    2013-03-01

    The aim of this study was to evaluate Gambusia spp. (mosquito-fish) mercury bio-concentration factor in relation to marsh surface water sulfate concentration. As part of the everglades regional environmental monitoring and assessment marsh biogeochemical parameters were collected by the US Environmental Protection agency between 1995 and 2005 within the Everglades Protection Area and Everglades National Park (ENP). Surface water sulfate and methyl-mercury concentration data in combination with mosquito-fish total mercury concentration data was used to elucidate the gambusia mercury bio-concentration and surface water sulfate relationship. Previous studies hypothesized that the relationship of biota mercury and surface water sulfate concentrations is unimodal. However this study shows that the relationship of biota mercury and sulfate surface water concentrations in mosquito-fish adheres closely with a log-log relationship. Furthermore mosquito-fish bio-concentration factor were similar for Water Conservation Area (WCA) 1 and WCA2, while WCA3 and ENP were significantly different between all pairs throughout the study period. This difference in hypothesized relationships versus the relationship defined in this study could be the result of life span (extent of exposure) or life history of mosquito-fish. PMID:23269441

  8. [Lactobacilli of freshwater fishes].

    PubMed

    Kvasnikov, E I; Kovalenko, N K; Materinskaia, L G

    1977-01-01

    Normal microflora in the intestinal tract of fishes inhabiting fresh-water reservoirs includes lactic bacteria. The number of the bacteria depends on the animal species, the composition of food, the age, and the season. The highest number of these microorganisms (hundreds of millions per gram of the intestinal content) is found in carps. Enterococci are most often encountered in fishes inhabiting ponds: Streptococcus faecalis Andrewes a. Horder, Str. faecium Orla-Jensen, Str. bovis Orla-Jensen. Lactobacilli are more typical of fishes in water reserviors: Lactobacillus plantarum (Orla-Jensen) Bergey et al., L. casei (Orla-Jensen) Hansen a. Lessel, L. casei var. casei, L. casei var. rhamnosus, L. Casei var. alactosus, L. leichmannii (Henneberg) Bergey et al., L. acidophillus (Moro) Hansen a. Mocquot, L. Fermenti Beijerinck, L. cellobiosus Rogosa et al., L. Buchneri (Henneberg) Bergey et al. The content of lactic bacteria varies in water reservoirs; their highest content is found in ooze (tens of thousands per gram). PMID:909475

  9. Folkbiology of Freshwater Fish

    ERIC Educational Resources Information Center

    Medin, Douglas L.; Ross, Norbert O.; Atran, Scott; Cox, Douglas; Coley, John; Proffitt, Julia B.; Blok, Sergey

    2006-01-01

    Cross-cultural comparisons of categorization often confound cultural factors with expertise. This paper reports four experiments on the conceptual behavior of Native American and majority-culture fish experts. The two groups live in the same general area and engage in essentially the same set of fishing-related behaviors. Nonetheless, cultural…

  10. Bioconcentration and depuration of endosulfan sulfate in mosquito fish (Gambusia affinis).

    PubMed

    Hoang, Tham C; Rand, Gary M; Gardinali, Piero R; Castro, Joffre

    2011-07-01

    Endosulfan is an insecticide which has been widely used in agriculture. The technical grade material consists of two isomers (alpha and beta). Under natural environmental conditions, endosulfan is metabolized through oxidation and the main metabolite in the environment is endosulfan sulfate. Most ecotoxicology research has been conducted with technical grade endosulfan to determine effects on non-target aquatic organisms. Little data on the effects of endosulfan sulfate on aquatic organisms are available in the literature. This study characterizes endosulfan sulfate bioconcentration and depuration in mosquito fish (Gambusia affinis). During the study, G. affinis was exposed to an environmentally relevant endosulfan sulfate concentration of 0.25 μg L(-1) for 5 weeks (uptake phase) followed by a 3-week period (depuration phase) in clean water. This study found that G. affinis bioconcentrated endosulfan sulfate. During the exposure phase, fish tissue concentrations of endosulfan sulfate increased with time up to 730 μg kg(-1) dw or 215 μg kg(-1) ww. The bioconcentration data followed Michaelis-Menten kinetics better than the one-compartment first order kinetics (1-CFOK). Using these models, the bioconcentration factors for endosulfan sulfate-exposed G. affinis were from 687 to 888 L kg(-1) in wet weight or 2263 to 2936 L kg(-1) in dry weight. During the depuration phase, endosulfan sulfate concentrations in tissue significantly decreased and the data followed first order kinetics. The half-life of endosulfan sulfate in G. affinis was about 9 d. There was no significant difference in standard length or weight between control and exposed fish. The growth data followed the von Bertalanffy growth model. However, the condition factor of exposed fish increased with time during the exposure phase. PMID:21550631

  11. Water quality for freshwater fish

    SciTech Connect

    Howells, G. )

    1994-01-01

    This timely and up-to-date volume brings together recent critical reviews on water quality requirements for freshwater fish commissioned by the European Inland Fisheries Advisory Commission, an agency of the United Nations Food and Agriculture Organization. It provides a unique and authoritative source of critically evaluated water quality data concerning the effects of chromium, nickel, aluminum and nitrite on freshwater fish and includes an assessment of the toxicity of mixtures. The reports presented in this volume cover all stages of the life cycle and relevant trophic levels, including aquatic invertebrates and plants and potential bioaccumulation through the food chain. An extensive bibliography is provided for each chapter as well as a glossary of terms and a list of fish species mentioned in the text. This compilation of papers is the definitive reference volume for chemists, biologists, ecologists and toxicologists as well as for water resource managers concerned with management and control of pollution in fresh waters.

  12. Gravid Spot Predicts Developmental Progress and Reproductive Output in a Livebearing Fish, Gambusia holbrooki

    PubMed Central

    Norazmi-Lokman, Nor Hakim; Purser, G. J.; Patil, Jawahar G.

    2016-01-01

    In most livebearing fish, the gravid spot is an excellent marker to identify brooding females, however its use to predict progress of embryonic development, brood size, timing of parturition and overall reproductive potential of populations remain unexplored. Therefore, to understand these relationships, this study quantified visual attributes (intensity and size) of the gravid spot in relation to key internal development in Gambusia holbrooki. Observations show that the colour of the gravid spot arises from progressive melanisation on the surface of the ovarian sac at its hind margin, rather than melanisation of the developing embryos or the skin of the brooding mother. More importantly, the gravid spot intensity and size were closely linked with both developmental stages and clutch size, suggesting their reliable use as external surrogates of key internal developmental in the species. Using predictive consistency of the gravid spot, we also determined the effect of rearing temperature (23°C and 25°C) on gestation period and parturition behaviour. The results show that gestation period was significantly reduced (F = 364.58; df = 1,48; P˃0.05) at 25°C. However there was no significant difference in average number of fry parturated in the two temperature groups (P<0.05), reaffirming that gravid spot intensity is a reliable predictor of reproductive output. The parturition in the species occurred predominantly in the morning and in contrast to earlier reports, tails of the fry emerged first with a few exceptions of head-first, twin and premature births. This study demonstrates utility of the gravid spot for downstream reproductive investigations in a live-bearing fish both in the field and laboratory. The reproducibility of the relationships (intensity with both developmental stage and clutch size), imply that they are also relevant to wild populations that experience varying temperature climes and stressors, significant deviations of which may serve as

  13. Gravid Spot Predicts Developmental Progress and Reproductive Output in a Livebearing Fish, Gambusia holbrooki.

    PubMed

    Norazmi-Lokman, Nor Hakim; Purser, G J; Patil, Jawahar G

    2016-01-01

    In most livebearing fish, the gravid spot is an excellent marker to identify brooding females, however its use to predict progress of embryonic development, brood size, timing of parturition and overall reproductive potential of populations remain unexplored. Therefore, to understand these relationships, this study quantified visual attributes (intensity and size) of the gravid spot in relation to key internal development in Gambusia holbrooki. Observations show that the colour of the gravid spot arises from progressive melanisation on the surface of the ovarian sac at its hind margin, rather than melanisation of the developing embryos or the skin of the brooding mother. More importantly, the gravid spot intensity and size were closely linked with both developmental stages and clutch size, suggesting their reliable use as external surrogates of key internal developmental in the species. Using predictive consistency of the gravid spot, we also determined the effect of rearing temperature (23 °C and 25 °C) on gestation period and parturition behaviour. The results show that gestation period was significantly reduced (F = 364.58; df = 1,48; P ˃ 0.05) at 25 °C. However there was no significant difference in average number of fry parturated in the two temperature groups (P<0.05), reaffirming that gravid spot intensity is a reliable predictor of reproductive output. The parturition in the species occurred predominantly in the morning and in contrast to earlier reports, tails of the fry emerged first with a few exceptions of head-first, twin and premature births. This study demonstrates utility of the gravid spot for downstream reproductive investigations in a live-bearing fish both in the field and laboratory. The reproducibility of the relationships (intensity with both developmental stage and clutch size), imply that they are also relevant to wild populations that experience varying temperature climes and stressors, significant deviations of which may serve as

  14. Acute toxicity of certain organochlorine, organophosphorus, synthetic pyrethroid and microbial insecticides to the mosquito fish Gambusia affinis (Baird and Girard).

    PubMed

    Mittal, P K; Adak, T; Sharma, V P

    1991-09-01

    Acute toxicity of certain organochlorine, organophosphorus, synthetic pyrethroid and microbial insecticides to the mosquito fish Gambusia affinis were determined to collect baseline data for selecting the resistant strains of the fish. The synthetic pyrethroid, Lambdacyhalothrin was most toxic to the fish (LC50 = 0.0022 ppm), followed by deltamethrin, cypermethrin and fenvalerate. Organochlorine insecticides, DDT and gamma-HCH, were less toxic than the pyrethroids, and these were followed by organophosphorus insecticides, malathion, fenthion, monocrotophos and temephos. The last two insecticides were least toxic among the different chemical insecticides (LC50 greater than 80 ppm ai). The microbial insecticide ABG-6262 (Vectolex 2.5 AS), a Bacillus sphaericus preparation, was totally harmless to the fish at 2500 microliters/l up to one week. PMID:1822454

  15. Effects of Pollution on Freshwater Fish.

    ERIC Educational Resources Information Center

    Brungs, W. A.; And Others

    1978-01-01

    Presents a literature review of the effects of pollution on freshwater fish, covering publications of 1976-77. This review includes: (1) water quality; (2) pesticide pollutants; (3) chemical pollutants; (4) miscellaneous pollutants; and (5) physical factors of pollution on freshwater fish. A list of 338 references is also presented. (HM)

  16. Toxicological effects of the herbicide oxyfluorfen on acetylcholinesterase in two fish species: Oreochromis niloticus and Gambusia affinis.

    PubMed

    Hassanein, Hamdy M A

    2002-01-01

    The alterations of the AChE activity in the brains of two fresh water fishes; Oreochromis niloticus and Gambusia affinis were measured after exposure to acute, sub-acute and chronic concentrations from the widely used herbicide; oxyfluorfen. Bioassays were conducted under controlled laboratory conditions. The used concentrations were acute: LC50 for 6 days, sub-acute 1/3 LC50 for 15 days and chronic 1/10 LC50 for 30 days. The obtained results showed marked inhibitory effects of the herbicide on the activity of AChE in both fishes. However, these effects were more pronounced in O. niloticus where the decline in the enzyme activity ranged from 19.7 to 81.28% while in case of G. affinis it ranged from 5.7 to 36.7%. These findings demonstrate that G. affinis is most tolerant to oxyfluorfen toxicity compared with O. niloticus. PMID:12046652

  17. Why are freshwater fish so threatened?

    USGS Publications Warehouse

    Closs, Gerard P.; Angermeier, Paul; Darwall, William R.T.; Balcombe, Stephen R.

    2015-01-01

    Understanding why so many freshwater fish species are threatened requires some understanding of their biology, diversity, distribution, biogeography and ecology, but also some appreciation of the social, economic and political forces that are causing humans to destroy the natural ecosystems upon which we all ultimately depend. To begin to understand the diversity of freshwater fishes, we first need to consider the processes that generated and continue to sustain the diversity of species we see today. Based on an understanding of how freshwater fish diversity is generated and sustained, we consider how vulnerable or resilient various freshwater fishes are to the range of anthropogenic impacts that impinge on freshwater ecosystems. Finally, we discuss how social, political and economic drivers influence human impacts on natural systems, and the changes needed to current models of development that can lead to a sustainable future for humans and the diverse range of freshwater fish species with which we share our planet. The aim of this chapter is to provide an overview of the key issues and threats driving the declines in freshwater fish diversity identified in Chapter 1; subsequent chapters provide more detail on the key issues and address our options for developing a sustainable future for freshwater fishes.

  18. Uptake and depuration of pharmaceuticals in reclaimed water by mosquito fish (Gambusia holbrooki): a worst-case, multiple-exposure scenario.

    PubMed

    Wang, Jian; Gardinali, Piero R

    2013-08-01

    Previous studies showed that caffeine, diphenhydramine, and carbamazepine were bioconcentrated by mosquito fish (Gambusia holbrooki) from freshwater bodies directly affected by reclaimed water. To understand the uptake, depuration, and bioconcentration factors (BCFs) under the worst-case conditions, the authors exposed 84 mosquito fish to reclaimed water under static renewal for 7 d, followed by a 14-d depuration phase in clean water. Characterization of the exposure media revealed the presence of 26 pharmaceuticals, whereas only 5 pharmaceuticals-caffeine, diphenhydramine, diltiazem, carbamazepine, and ibuprofen-were present in the organisms after only 5 h of exposure. Caffeine, diltiazem, and carbamazepine were quickly taken up by mosquito fish following a similar uptake curve. Diphenhydramine and ibuprofen, on the other hand, were more gradually taken up by mosquito fish but were also eliminated fairly quickly, resulting in the 2 shortest depuration half-lives at 34 h and 32 h, respectively. For comparison, BCFs based on rate constants (BCFb ), steady-state concentrations (BCFa ), and saturation-state concentrations (BCFc ) were calculated. Values of BCFb ranged from 0.23 to 29 and increased in the order of caffeine < carbamazepine < diltiazem < diphenhydramine < ibuprofen. Values of BCFa and BCFc ranged from 2.0 to 28 and increased in the order of carbamazepine < caffeine < diltiazem < diphenhydramine < ibuprofen. This is the first study using a nonartificial exposure-treated wastewater matrix to generate pharmacokinetic data for pharmaceutical mixtures in aquatic organisms. Environ Toxicol Chem 2013;32:1752-1758. © 2013 SETAC. PMID:23595768

  19. NATIVE FRESHWATER FISH AND MUSSEL SPECIES RICHNESS

    EPA Science Inventory

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

  20. EFFECTS OF POLLUTION ON FRESHWATER FISH

    EPA Science Inventory

    An extensive literature review is presented which is concerned with the effects of pollutants (metals, pesticides, detergents, industrial wastes) on freshwater fish; chemical and biological methods for identifying and determining the effects of such pollutants; and the effects of...

  1. In Brief: Europe's freshwater fish threatened

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2007-11-01

    Two hundred of Europe's 522 freshwater fish species are threatened with extinction and 12 are already extinct, according to the Handbook of European Freshwater Fishes, published in collaboration with the World Conservation Union (IUCN) and released on 1 November 2007. IUCN notes that the main threats to fish species stem from development and population growth and include water withdrawals, large dams, and inappropriate fisheries management that has led to overfishing and the introduction of alien species. Authors Maurice Kottelat, former president of the European Ichthyological Society, and Jörg Freyhof, scientist from Leibniz Institute of Freshwater Ecology, noted that fish conservation should be managed by agencies in charge of conservation, and not as a crop by agencies in charge of agriculture. William Darwall, senior program officer with IUCN's Species Program, said the species ``are critical to the freshwater ecosystems upon which we do depend, such as for water purification and flood control.'' For more information, visit the Web site: http://www.iucn.org.

  2. Monogeneans of freshwater fishes from cenotes (sinkholes) of the Yucatan Peninsula, Mexico.

    PubMed

    Mendoza-Franco, E F; Scholz, T; Vivas-Rodríguez, C; Vargas-Vázquez, J

    1999-01-01

    During a survey of the parasites of freshwater fishes from cenotes (sinkholes) of the Yucatan Peninsula the following species of monogeneans were found on cichlid, pimelodid, characid and poeciliid fishes: Sciadicleithrum mexicanum Kritsky, Vidal-Martinez et Rodriguez-Canul, 1994 from Cichlasoma urophthalmus (Günther) (type host), Cichlasoma friedrichsthali (Heckel), Cichlasoma octofasciatum (Regan), and Cichlasoma synspilum Hubbs, all new host records; Sciadicleithrum meekii Mendoza-Franco, Scholz et Vidal-Martínez, 1997 from Cichlasoma meeki (Brind); Urocleidoides chavarriai (Price, 1938) and Urocleidoides travassosi (Price, 1938) from Rhamdia guatemalensis (Günther); Urocleidoides costaricensis (Price et Bussing, 1967), Urocleidoides heteroancistrium (Price et Bussing, 1968), Urocleidoides anops Kritsky et Thatcher, 1974, Anacanthocotyle anacanthocotyle Kritsky et Fritts, 1970, and Gyrodactylus neotropicalis Kritsky et Fritts, 1970 from Astyanax fasciatus; and Gyrodactylus sp. from Gambusia yucatana Regan. Urocleidoides chavarriai, U. travassosi, U. costaricensis, U. heteroancistrium, U. anops, Anacanthocotyle anacanthocotyle and Gyrodactylus neotropicalis are reported from North America (Mexico) for the first time. These findings support the idea about the dispersion of freshwater fishes and their monogenean parasites from South America through Central America to southeastern Mexico, following the emergence of the Panamanian isthmus between 2 and 5 million years ago. PMID:10730199

  3. Zebrafish (Danio rerio) behavioural response to bioinspired robotic fish and mosquitofish (Gambusia affinis).

    PubMed

    Polverino, Giovanni; Porfiri, Maurizio

    2013-12-01

    The field of ethorobotics holds promise in aiding fundamental research in animal behaviour, whereby it affords fully controllable and easily reproducible experimental tools. Most of the current ethorobotics studies are focused on the behavioural response of a selected target species as it interacts with a biologically-inspired robot in controlled laboratory conditions. In this work, we first explore the interactions between two social fish species and a robotic fish, whose design is inspired by salient visual features of one of the species. Specifically, this study investigates the behavioural response of small shoals of zebrafish interacting with a zebrafish-inspired robotic fish and small shoals of mosquitofish in a basic ecological context. Our results demonstrate that the robotic fish differentially influences the behaviour of the two species by consistently attracting zebrafish, while repelling mosquitofish. This selective behavioural control is successful in spatially isolating the two species, which would otherwise exhibit prey-predator interactions, with mosquitofish attacking zebrafish. PMID:23999758

  4. Carcinogens and cancers in freshwater fishes.

    PubMed Central

    Black, J J; Baumann, P C

    1991-01-01

    Epizootics of neoplasms in freshwater fish species are considered in relation to circumstantial and experimental evidence that suggest that some epizootics of neoplasia of hepatocellular, cholangiocellular, epidermal, and oral epithelial origin may be causally related to contaminant exposure. Although there is concern for the safety of consuming fish affected with neoplasms, this concern may be misdirected as direct transmission of cancer by ingesting cancerous tissue would seem unlikely. Of greater concern is the matter of toxic and cancer-causing chemicals present in edible fish that exhibit neoplasia as a symptom of past exposure via residence in a polluted waterway. There is ample evidence to suggest that contaminant chemicals ingested via contaminated Great Lakes fish may already be affecting both human and ecosystem health, but these effects are subtle and may require new approaches to the study of the affected systems. PMID:2050071

  5. The decline of North American freshwater fishes

    USGS Publications Warehouse

    Walsh, Stephen J.; Jelks, Howard L.; Burkhead, Noel M.

    2009-01-01

    North America has a broad array of freshwater ecosystems because of the continent's complex geography and geological history. Within a multitude of habitats—that include streams, large rivers, natural lakes, springs, and wetlands—rich assemblages of fishes reside, representing diverse taxonomic groups with unique ecological requirements. They face an unprecedented conservation crisis.1 In the last few decades, the proportion of inland fishes of North America, which are considered imperiled or extinct, increased from 20 to 40%.2 Although extinctions have occurred, many species and populations are declining in range size and abundance. The fish biota of the continent as a whole remains diverse; however, we can take action to stem any further declines.

  6. Forests fuel fish growth in freshwater deltas

    PubMed Central

    Tanentzap, Andrew J.; Szkokan-Emilson, Erik J.; Kielstra, Brian W.; Arts, Michael T.; Yan, Norman D.; Gunn, John M.

    2014-01-01

    Aquatic ecosystems are fuelled by biogeochemical inputs from surrounding lands and within-lake primary production. Disturbances that change these inputs may affect how aquatic ecosystems function and deliver services vital to humans. Here we test, using a forest cover gradient across eight separate catchments, whether disturbances that remove terrestrial biomass lower organic matter inputs into freshwater lakes, thereby reducing food web productivity. We focus on deltas formed at the stream-lake interface where terrestrial-derived particulate material is deposited. We find that organic matter export increases from more forested catchments, enhancing bacterial biomass. This transfers energy upwards through communities of heavier zooplankton, leading to a fourfold increase in weights of planktivorous young-of-the-year fish. At least 34% of fish biomass is supported by terrestrial primary production, increasing to 66% with greater forest cover. Habitat tracers confirm fish were closely associated with individual catchments, demonstrating that watershed protection and restoration increase biomass in critical life-stages of fish. PMID:24915965

  7. Forests fuel fish growth in freshwater deltas.

    PubMed

    Tanentzap, Andrew J; Szkokan-Emilson, Erik J; Kielstra, Brian W; Arts, Michael T; Yan, Norman D; Gunn, John M

    2014-01-01

    Aquatic ecosystems are fuelled by biogeochemical inputs from surrounding lands and within-lake primary production. Disturbances that change these inputs may affect how aquatic ecosystems function and deliver services vital to humans. Here we test, using a forest cover gradient across eight separate catchments, whether disturbances that remove terrestrial biomass lower organic matter inputs into freshwater lakes, thereby reducing food web productivity. We focus on deltas formed at the stream-lake interface where terrestrial-derived particulate material is deposited. We find that organic matter export increases from more forested catchments, enhancing bacterial biomass. This transfers energy upwards through communities of heavier zooplankton, leading to a fourfold increase in weights of planktivorous young-of-the-year fish. At least 34% of fish biomass is supported by terrestrial primary production, increasing to 66% with greater forest cover. Habitat tracers confirm fish were closely associated with individual catchments, demonstrating that watershed protection and restoration increase biomass in critical life-stages of fish. PMID:24915965

  8. Climate and local abundance in freshwater fishes

    PubMed Central

    Knouft, Jason H.; Anthony, Melissa M.

    2016-01-01

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

  9. Climate and local abundance in freshwater fishes.

    PubMed

    Knouft, Jason H; Anthony, Melissa M

    2016-06-01

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

  10. Extinction rates in North American freshwater fishes, 1900-2010

    USGS Publications Warehouse

    Burkhead, Noel M.

    2012-01-01

    Widespread evidence shows that the modern rates of extinction in many plants and animals exceed background rates in the fossil record. In the present article, I investigate this issue with regard to North American freshwater fishes. From 1898 to 2006, 57 taxa became extinct, and three distinct populations were extirpated from the continent. Since 1989, the numbers of extinct North American fishes have increased by 25%. From the end of the nineteenth century to the present, modern extinctions varied by decade but significantly increased after 1950 (post-1950s mean = 7.5 extinct taxa per decade). In the twentieth century, freshwater fishes had the highest extinction rate worldwide among vertebrates. The modern extinction rate for North American freshwater fishes is conservatively estimated to be 877 times greater than the background extinction rate for freshwater fishes (one extinction every 3 million years). Reasonable estimates project that future increases in extinctions will range from 53 to 86 species by 2050.

  11. Institutional development of freshwater fish stocking in Mexico.

    PubMed

    Ibáñez, A L; Pérez-Ramírez, M; García-Calderón, J L

    2014-12-01

    By using freshwater fish stocking information from the Mexican government, this work described the current situation of the national stocking and its associated fishery policy. There is a lack of effective freshwater stocking programmes as a result of limited fisheries management, unharmonized fisheries regulations and institutional performance. The fry production has decreased from 140 to 20 million in the past 11 years. PMID:25146570

  12. THREATENED AND ENDANGERED FRESHWATER FISH AND MUSSEL SPECIES RICHNESS

    EPA Science Inventory

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

  13. Predicting spatial similarity of freshwater fish biodiversity

    PubMed Central

    Azaele, Sandro; Muneepeerakul, Rachata; Maritan, Amos; Rinaldo, Andrea; Rodriguez-Iturbe, Ignacio

    2009-01-01

    A major issue in modern ecology is to understand how ecological complexity at broad scales is regulated by mechanisms operating at the organismic level. What specific underlying processes are essential for a macroecological pattern to emerge? Here, we analyze the analytical predictions of a general model suitable for describing the spatial biodiversity similarity in river ecosystems, and benchmark them against the empirical occurrence data of freshwater fish species collected in the Mississippi–Missouri river system. Encapsulating immigration, emigration, and stochastic noise, and without resorting to species abundance data, the model is able to reproduce the observed probability distribution of the Jaccard similarity index at any given distance. In addition to providing an excellent agreement with the empirical data, this approach accounts for heterogeneities of different subbasins, suggesting a strong dependence of biodiversity similarity on their respective climates. Strikingly, the model can also predict the actual probability distribution of the Jaccard similarity index for any distance when considering just a relatively small sample. The proposed framework supports the notion that simplified macroecological models are capable of predicting fundamental patterns—a theme at the heart of modern community ecology. PMID:19359481

  14. Freshwater Fish Assemblage Patterns in Rhode Island Streams and Rivers

    EPA Science Inventory

    Patterns in fish assemblages in streams and rivers can inform watershed and water management, yet these patterns are not well characterized for the U.S. state of Rhode Island. Here we relate freshwater fish data collected by the Rhode Island Department of Environmental Managemen...

  15. Extinction rates in North American freshwater fishes, 1900-2010

    USGS Publications Warehouse

    Burkhead, Noel M.

    2012-01-01

    Widespread evidence shows that the modern rates of extinction in many plants and animals exceed background rates in the fossil record. In the present article, I investigate this issue with regard to North American freshwater fishes. From 1898 to 2006, 57 taxa became extinct, and three distinct populations were extirpated from the continent. Since 1989, the numbers of extinct North American fishes have increased by 25%. From the end of the nineteenth century to the present, modern extinctions varied by decade but significantly increased after 1950 (post-1950s mean = 7.5 extinct taxa per decade). The modern extinction rate for North American freshwater fishes is conservatively estimated to be 877 times greater than the background extinction rate for freshwater fishes (one extinction every 3 million years). Reasonable estimates project that future increases in extinctions will range from 53 to 86 species by 2050.

  16. Heads or tails: do stranded fish (mosquitofish, Gambusia affinis) know where they are on a slope and how to return to the water?

    PubMed

    Boumis, Robert J; Ferry, Lara A; Pace, Cinnamon M; Gibb, Alice C

    2014-01-01

    Aquatic vertebrates that emerge onto land to spawn, feed, or evade aquatic predators must return to the water to avoid dehydration or asphyxiation. How do such aquatic organisms determine their location on land? Do particular behaviors facilitate a safe return to the aquatic realm? In this study, we asked: will fully-aquatic mosquitofish (Gambusia affinis) stranded on a slope modulate locomotor behavior according to body position to facilitate movement back into the water? To address this question, mosquitofish (n = 53) were placed in four positions relative to an artificial slope (30° inclination) and their responses to stranding were recorded, categorized, and quantified. We found that mosquitofish may remain immobile for up to three minutes after being stranded and then initiate either a "roll" or a "leap". During a roll, mass is destabilized to trigger a downslope tumble; during a leap, the fish jumps up, above the substrate. When mosquitofish are oriented with the long axis of the body at 90° to the slope, they almost always (97%) initiate a roll. A roll is an energetically inexpensive way to move back into the water from a cross-slope body orientation because potential energy is converted back into kinetic energy. When placed with their heads toward the apex of the slope, most mosquitofish (>50%) produce a tail-flip jump to leap into ballistic flight. Because a tail-flip generates a caudually-oriented flight trajectory, this locomotor movement will effectively propel a fish downhill when the head is oriented up-slope. However, because the mass of the body is elevated against gravity, leaps require more mechanical work than rolls. We suggest that mosquitofish use the otolith-vestibular system to sense body position and generate a behavior that is "matched" to their orientation on a slope, thereby increasing the probability of a safe return to the water, relative to the energy expended. PMID:25162613

  17. Biomarkers of Type II Synthetic Pyrethroid Pesticides in Freshwater Fish

    PubMed Central

    2014-01-01

    Type II synthetic pyrethroids contain an alpha-cyano group which renders them more neurotoxic than their noncyano type I counterparts. A wide array of biomarkers have been employed to delineate the toxic responses of freshwater fish to various type II synthetic pyrethroids. These include hematological, enzymatic, cytological, genetic, omic and other types of biomarkers. This review puts together the applications of different biomarkers in freshwater fish species in response to the toxicity of the major type II pyrethroid pesticides and assesses their present status, while speculating on the possible future directions. PMID:24868555

  18. Effects of pollution on freshwater fish and amphibians

    SciTech Connect

    Pickering, Q.H.; Hunt, E.P.; Phipps, G.L.; Roush, T.H.; Smith, W.E.; Spehar, D.L.; Stephan, C.E.; Tanner, D.K.

    1983-06-01

    A literature review is presented dealing with studies on the effects of pollution on freshwater fish and amphibians. The pollutants studied included acid mine drainage, PCBs, cadmium, lead, naphthalene, plutonium, in addition to several studies dealing with pH effects. (JMT)

  19. Restricted-Range Fishes and the Conservation of Brazilian Freshwaters

    PubMed Central

    Nogueira, Cristiano; Buckup, Paulo A.; Menezes, Naercio A.; Oyakawa, Osvaldo T.; Kasecker, Thais P.; Ramos Neto, Mario B.; da Silva, José Maria C.

    2010-01-01

    Background Freshwaters are the most threatened ecosystems on earth. Although recent assessments provide data on global priority regions for freshwater conservation, local scale priorities remain unknown. Refining the scale of global biodiversity assessments (both at terrestrial and freshwater realms) and translating these into conservation priorities on the ground remains a major challenge to biodiversity science, and depends directly on species occurrence data of high taxonomic and geographic resolution. Brazil harbors the richest freshwater ichthyofauna in the world, but knowledge on endemic areas and conservation in Brazilian rivers is still scarce. Methodology/Principal Findings Using data on environmental threats and revised species distribution data we detect and delineate 540 small watershed areas harboring 819 restricted-range fishes in Brazil. Many of these areas are already highly threatened, as 159 (29%) watersheds have lost more than 70% of their original vegetation cover, and only 141 (26%) show significant overlap with formally protected areas or indigenous lands. We detected 220 (40%) critical watersheds overlapping hydroelectric dams or showing both poor formal protection and widespread habitat loss; these sites harbor 344 endemic fish species that may face extinction if no conservation action is in place in the near future. Conclusions/Significance We provide the first analysis of site-scale conservation priorities in the richest freshwater ecosystems of the globe. Our results corroborate the hypothesis that freshwater biodiversity has been neglected in former conservation assessments. The study provides a simple and straightforward method for detecting freshwater priority areas based on endemism and threat, and represents a starting point for integrating freshwater and terrestrial conservation in representative and biogeographically consistent site-scale conservation strategies, that may be scaled-up following naturally linked drainage systems

  20. Freshwater fishes of Patagonia: conservation and fisheries.

    PubMed

    Cussac, V E; Habit, E; Ciancio, J; Battini, M A; Riva Rossi, C; Barriga, J P; Baigún, C; Crichigno, S

    2016-07-01

    The absence of much literature on the Patagonian fish fauna in comparison with that of the neotropics, has previously been blamed on its poor species diversity. Knowledge of the fishes of Patagonia, however, rose sharply at the beginning of the present century, allowing for an understanding of the complex biogeographical history that has led to the present diversity and distribution patterns. There are several new and potential threats to biodiversity and conservation of Patagonian fishes, such as the introduction of exotic species, damming, climate change and changes geared to safeguard economic interests, often acting synergistically. A great amount of new information is now available and the aim of the present review is to articulate this knowledge in a comprehensive way in order to aid in the development of tools to face the increasing challenges posed by environmental change and human activity. Knowledge about fishes of Patagonia has grown at the same time as human actions, and presence. PMID:27284012

  1. Book review: Ecology of North American freshwater fishes

    USGS Publications Warehouse

    Bonar, Scott A.

    2014-01-01

    This book will be important in courses for upper undergraduates studying fish ecology or for graduate students. However, it will also be an excellent reference for the fishery manager who asks ‘Why does this fish do that?’. With the wealth of great information contained in Ross’ book, chances are an answer will be found. Review info: Ecology of North American freshwater fishes. Edited by Stephen T. Ross, 2013. ISBN: 978-0520249455, 408 pp.

  2. Toxicity of 33 NCS to freshwater fish and sea lamprey

    USGS Publications Warehouse

    Marking, Leif L.; King, Everett L.; Walker, Charles R.; Howell, John H.

    1970-01-01

    The chemical 33NCS (3'-chloro-3-nitrosalicylanilide) was evaluated as a fish control agent and as a larvicide for sea lampreys at the Fish Control Laboratories of the Bureau of Sport Fisheries and Wildlife and the Hammond Bay Biological Station of the Bureau of Commercial Fisheries. The chemical is rapidly toxic to many species. Sea lampreys, bowfin, and channel catfish are the most sensitive species. Carp are more sensitive than trouts or sunfishes. Use of 33NCS in selective control of freshwater fishes or sea lampreys requires precise control because its toxicity is strongly influenced by variations in water quality.

  3. The gastrointestinal phage communities of the cultivated freshwater fishes.

    PubMed

    He, Yang; Yang, Hongjiang

    2015-03-01

    The phage communities in the gut of 62 cultivated freshwater fish were investigated by culture-based methods. Using three selective media, 445 pathogenic bacilli strains were isolated and used as indicators for subsequent phage isolations. Totally, 63 phages were detected and the respective host strains were identified with the comparative sequence analysis of 16S rRNA gene, including Aeromonas (29), Vibrio (1), Citrobacter (16), Serratia (4), Enterobacter (2), Proteus (3), Buttiauxella (2), Plesiomonas (2), Kluyvera (1), Morgenella (2) and Providencia (1). The diversity of Aeromonas phages was assessed by discrimination of their host strains with random amplified polymorphic DNA method. Furthermore, the isolated Aeromonas phages were characterized by host range and growth inhibition assay. The results demonstrated that there were abundant and diverse phage populations in the gut environment of the cultivated freshwater fishes. The phages could contribute to the microbiota balance in the gut ecosystem of fishes and provide reliable phage sources for future applications. PMID:25743067

  4. Effects of mosquitofish, Gambusia affinis, on channel catfish, Ictalurus puncatatus, production ponds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mosquitofish, Gambusia sp., have been spread throughout the world to biologically control mosquitoes. However, the fish has gained a reputation as an invasive species and has been implicated in displacing native aquatic species. Gambusia affinis are native to the southeastern United States and commo...

  5. Effects of mosquitofish, gambusia affinis, on channel catfish, Ictalurus puncatatus, production ponds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mosquitofish, Gambusia sp., have been spread throughout the world to biologically control mosquitoes. However, the fish has gained a reputation as an invasive species and has been implicated in displacing native aquatic species. Gambusia affinis is native to the southeastern United States and comm...

  6. Classification of species attributes for Pacific Northwest freshwater fishes

    USGS Publications Warehouse

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

    1999-01-01

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

  7. Evolutionary landscape of amphibians emerging from ancient freshwater fish inferred from complete mitochondrial genomes.

    PubMed

    Wang, Xiao-Tong; Zhang, Yan-Feng; Wu, Qian; Zhang, Hao

    2012-05-01

    It is very interesting that the only extant marine amphibian is the marine frog, Fejervarya cancrivora. This study investigated the reasons for this apparent rarity by conducting a phylogenetic tree analysis of the complete mitochondrial genomes from 14 amphibians, 67 freshwater fishes, four migratory fishes, 35 saltwater fishes, and one hemichordate. The results showed that amphibians, living fossil fishes, and the common ancestors of modern fishes are phylogenetically separated. In general, amphibians, living fossil fishes, saltwater fishes, and freshwater fishes are clustered in different clades. This suggests that the ancestor of living amphibians arose from a type of primordial freshwater fish, rather than the coelacanth, lungfish, or modern saltwater fish. Modern freshwater fish and modern saltwater fish were probably separated from a common ancestor by a single event, caused by crustal movement. PMID:22503684

  8. Standard methods for sampling North American freshwater fishes

    USGS Publications Warehouse

    Bonar, Scott A.; Hubert, Wayne A.; Willis, David W.

    2009-01-01

    This important reference book provides standard sampling methods recommended by the American Fisheries Society for assessing and monitoring freshwater fish populations in North America. Methods apply to ponds, reservoirs, natural lakes, and streams and rivers containing cold and warmwater fishes. Range-wide and eco-regional averages for indices of abundance, population structure, and condition for individual species are supplied to facilitate comparisons of standard data among populations. Provides information on converting nonstandard to standard data, statistical and database procedures for analyzing and storing standard data, and methods to prevent transfer of invasive species while sampling.

  9. Lead-induced biochemical changes in freshwater fish Oreochromis mossambicus

    SciTech Connect

    Ruparelia, S.G.; Verma, Y.; Mehta, N.S.; Salyed, S.R. )

    1989-08-01

    Lead, a non-essential and non-beneficial element has considerably added the problem of health hazard to human and experimental mammals. It has also received much attention over the past few years as potentially important aquatic pollutant. Fishes are of great nutritional significance and their intoxication by lead causes retardation of growth and deterioration in the nutritional value. Very little attention has been paid to biochemical changes which develop more quickly in response to toxicants than any apparent morphological changes. Therefore, the present investigation was undertaken to evaluate the effect of lead on plasma chemistry of freshwater fish Oreochromis mossambicus. This fish was selected because of its wide availability, edibility in India and its suitability as a model fish for toxicity testing. The variables such as glucose, cholesterol and protein representing carbohydrate, lipid and protein metabolism were studied.

  10. Homogenization patterns of the world’s freshwater fish faunas

    PubMed Central

    Villéger, Sébastien; Blanchet, Simon; Beauchard, Olivier; Oberdorff, Thierry; Brosse, Sébastien

    2011-01-01

    The world is currently undergoing an unprecedented decline in biodiversity, which is mainly attributable to human activities. For instance, nonnative species introduction, combined with the extirpation of native species, affects biodiversity patterns, notably by increasing the similarity among species assemblages. This biodiversity change, called taxonomic homogenization, has rarely been assessed at the world scale. Here, we fill this gap by assessing the current homogenization status of one of the most diverse vertebrate groups (i.e., freshwater fishes) at global and regional scales. We demonstrate that current homogenization of the freshwater fish faunas is still low at the world scale (0.5%) but reaches substantial levels (up to 10%) in some highly invaded river basins from the Nearctic and Palearctic realms. In these realms experiencing high changes, nonnative species introductions rather than native species extirpations drive taxonomic homogenization. Our results suggest that the “Homogocene era” is not yet the case for freshwater fish fauna at the worldwide scale. However, the distressingly high level of homogenization noted for some biogeographical realms stresses the need for further understanding of the ecological consequences of homogenization processes. PMID:22025692

  11. Consumption of freshwater fish in Kahnawake: Risks and benefits

    SciTech Connect

    Chan, H.M.; Trifonopoulos, M.; Ing, A.; Receveur, O.; Johnson, E.

    1999-02-01

    Kahnawake is a Mohawk community located on the south shore of the Saint Lawrence River near Montreal. A comprehensive study was conducted in 1996--1997 to address the local concern regarding health risks of contaminant exposure associated with freshwater fish consumption. Forty-two participants, including most of the identified active fishermen were interviewed. Walleye, perch, bullhead, and smallmouth bass were the species most consumed. Average daily intake of locally caught fish was 23 g/day. Nutrient and contaminant levels of locally collected fish were analyzed. Fish were good sources of protein, polyunsaturated fatty acids, calcium, zinc, and iron. Levels of cadmium, lead, arsenic, polychlorinated biphenyls (PCBs), and other chlorinated pesticides were at least 10 times lower than the guideline levels. Mercury levels of some predatory fish exceeded the guideline of 0.5 {micro}g/g. Average daily intakes of all contaminants were below the guideline levels by a factor of 10 except for mercury. Average mercury intake rate was about one-third that of the guideline level. Contrary to residents` perception, Kahnawake fish were not particularly contaminated. In view of the nutritional as well as cultural benefits, fishing and fish consumption may be promoted.

  12. Beginnings and success in preventing anophelism by means of gambusia fish on the island of Krk in Croatia from 1922 to 1927.

    PubMed

    Skrobonja, Ante; Materljan, Neven; Skrobonja, Ivana

    2010-08-01

    The introductory part has summarized the role of malaria in the course of history and various attempts of its eradication in Croatia before the World War I. Furthemore, there is a list of activities and results accomplished between 1922 and 1927 on the island of Krk by Dr. Otmar Trausmiller. After a systematic sanitation of all anopheles habitats, primarily natural and artificial bodies of still water, and introduction of imported gambusia to those bodies of water, anopheles was virtually eradicated on the island. What followed was an evident decrease of new malaria incidents, and in the campaign against malaria there was still major concern in the form of chronic patients and intensive quinine therapy. Today, about eighty years after it was introduced to Krk, gambusia still abides in ponds across the island and it represents one of the main factors in the protection against potential revival of indigenous malaria. PMID:21258304

  13. Fish stranding in freshwater systems: sources, consequences, and mitigation.

    PubMed

    Nagrodski, Alexander; Raby, Graham D; Hasler, Caleb T; Taylor, Mark K; Cooke, Steven J

    2012-07-30

    Fish can become stranded when water levels decrease, often rapidly, as a result of anthropogenic (e.g., canal drawdown, hydropeaking, vessel wakes) and natural (e.g., floods, drought, winter ice dynamics) events. We summarize existing research on stranding of fish in freshwater, discuss the sources, consequences, and mitigation options for stranding, and report current knowledge gaps. Our literature review revealed that ∼65.5% of relevant peer-reviewed articles were found to focus on stranding associated with hydropower operations and irrigation projects. In fact, anthropogenic sources of fish stranding represented 81.8% of available literature compared to only 19.9% attributed to natural fish stranding events. While fish mortality as a result of stranding is well documented, our analysis revealed that little is known about the sublethal and long-term consequences of stranding on growth and population dynamics. Furthermore, the contribution of stranding to annual mortality rates is poorly understood as are the potential ecosystem-scale impacts. Mitigation strategies available to deal with stranding include fish salvage, ramping rate limitations, and physical habitat works (e.g., to contour substrate to minimize stranding). However, a greater knowledge of the factors that cause fish stranding would promote the development and refinement of mitigation strategies that are economically and ecologically sustainable. PMID:22481278

  14. Histopathological study on parasites in freshwater ornamental fishes in Iran.

    PubMed

    Nematollahi, A; Jaberi, S; Helan, J Ashrafi; Sheikhzadeh, N

    2016-09-01

    During March 2012 through February 2013, 100 freshwater ornamental fishes in 22 species from some aquarium fish shops were examined. Specimens were dissected and tissue samples consisted of liver, kidney, spleen, heart, intestine, ovary, brain and eye were fixed in 10 % buffered formalin and sections were provided and stained with hematoxylin and eosin, Periodic Acid-Schiff, Giemsa and acid-fast staining (Ziehl-Neelsen). At present study six species of protozoans consisting of Eimeria spp. Cryptosporidium spp., Tetrahymena corlissi, Thecamoeba spp., Giardia spp., Myxobolus spp. and two metazoan parasite consisting of Nematoda spp. and Benedenia monticelli were identified. Thecamoeba, B. monticelli and Cryptosporidium spp. were not reported in previous Iranian studies and it is the first report of infestation to this parasite in ornamental fish in Iran. PMID:27605779

  15. A portable freshwater closed-system fish egg incubation system

    USGS Publications Warehouse

    Sutherland, Jenny L.; Manny, Bruce A.; Kennedy, Gregory W.; Roseman, Edward F.; Allen, Jeffrey D.; Black, M. Glen

    2014-01-01

    To identify fish eggs collected in the field to species, a portable closed-system fish egg incubation system was designed and used to incubate and hatch the eggs in the laboratory. The system is portable, small in scale (2.54 × 1.52 × 2.03 m), and affordable, with the approximate cost of the system being US$8,300 (2012). The main tank is 678 L and holds a battery of up to 21 (egg) incubation jars. The system includes three independent water pumping systems to (1) provide aerated water to hatching jars, (2) filter and sterilize incubation water, and (3) provide temperature-controlled water in the main tank bath and the incubation jars. The system was successfully used to incubate freshwater fish eggs to raise resulting larvae to the post-yolk-sac stage for three seasons (spring 2012, spring 2013, and fall 2013) over two consecutive years, at two different locations, enabling us to identify fish eggs to species by providing identifiable fish larvae from incubated fish eggs.

  16. Conservation status of imperiled north American freshwater and diadromous fishes

    USGS Publications Warehouse

    Jelks, H.L.; Walsh, S.J.; Burkhead, N.M.; Contreras-Balderas, Salvador; Diaz-Pardo, E.; Hendrickson, D.A.; Lyons, J.; Mandrak, N.E.; McCormick, F.; Nelson, Joseph S.; Platania, S.P.; Porter, B.A.; Renaud, C.B.; Schmitter-Soto, J. J.; Taylor, E.B.; Warren, M.L., Jr.

    2008-01-01

    This is the third compilation of imperiled (i.e., endangered, threatened, vulnerable) plus extinct freshwater and diadromous fishes of North America prepared by the American Fisheries Society's Endangered Species Committee. Since the last revision in 1989, imperilment of inland fishes has increased substantially. This list includes 700 extant taxa representing 133 genera and 36 families, a 92% increase over the 364 listed in 1989. The increase reflects the addition of distinct populations, previously non-imperiled fishes, and recently described or discovered taxa. Approximately 39% of described fish species of the continent are imperiled. There are 230 vulnerable, 190 threatened, and 280 endangered extant taxa, and 61 taxa presumed extinct or extirpated from nature. Of those that were imperiled in 1989, most (89%) are the same or worse in conservation status; only 6% have improved in status, and 5% were delisted for various reasons. Habitat degradation and nonindigenous species are the main threats to at-risk fishes, many of which are restricted to small ranges. Documenting the diversity and status of rare fishes is a critical step in identifying and implementing appropriate actions necessary for their protection and management.

  17. Development of intermediate foodstuff derived from freshwater fish in China

    NASA Astrophysics Data System (ADS)

    Wang, Xichang; Fukuda, Yutaka; Chen, Shunsheng; Yokoyama, Masahito; Cheng, Yudong; Yuan, Chunhong; Qu, Yinghong; Sakaguchi, Morihiko

    2005-07-01

    According to the three-dimensional contour maps showing the gel-forming properties of surimi derived from freshwater fish, 8 species of surimi were classified into two types. The V-valley type surimi (silver carp, big-head carp, Chinese snake head and blunt snout bream) shows easy setting, low resistance to gel collapse, high enhancement ability with two-step heating, and narrow optimum heating temperature and time area, which are of the same characteristics as the wall-eye pollack surimi. In contrast, the Plateau type surimi (tilapia, grass carp, mud carp and common carp) exhibits difficult setting, high resistance to gel collapse, no enhancement ability with two-step heating, and wide optimum heating temperature and time area. There are seasonal changes of gelling properties of silver carp surimi, and the setting ability of surimi gel is higher in winter and lower in summer. The marine fish meat gels and the freshwater fish meat gels have the same acceptability for inland Chinese according to the sensory evaluation results. A slight increase in sensory scorings of kamaboko gels occurred when the extract from walleye pollack muscle was added, especially in the odor scoring of silver carp kamaboko gels.

  18. Contrasting "Fish" Diversity Dynamics between Marine and Freshwater Environments.

    PubMed

    Guinot, Guillaume; Cavin, Lionel

    2015-08-31

    Two theoretical models have been proposed to describe long-term dynamics of diversification: the equilibrium model considers the Earth as a closed system with a fixed maximum biological carrying capacity, whereas the expansion model hypothesizes a continuously increasing diversification of life. Based on the analysis of the fossil record of all organisms, Benton suggested contrasting models of diversity dynamics between marine and continental realms. Diversity in marine environments is characterized by phases of rapid diversification followed by plateaux, i.e., an equilibrium model directly derived from insular biogeography theories, whereas diversity in continental environments is characterized by exponential growth. Previous studies that aimed at testing these models with empirical data were based on datasets extracted directly from the reading of the vagaries of the raw fossil record, without correcting for common fossil record biases (preservation and sampling). Although correction of datasets for the incompleteness of the fossil record is now commonly performed for addressing long-term biodiversity variations, only a few attempts have been made to produce diversity curves corrected by phylogenetic data from extant and extinct taxa. Here we show that phylogenetically corrected diversity curves for "fish" (actinopterygians and elasmobranchs) during the last 200 million years fit an equilibrium model in the marine realm and an expansion model in the freshwater realm. These findings demonstrate that the rate of diversification has decreased for marine fish over the Cenozoic but is in sharp expansion for freshwater fish. PMID:26279235

  19. Diversity, distribution, and conservation status of the native freshwater fishes of the southern United States

    USGS Publications Warehouse

    Warren, Melvin L., Jr.; Burr, Brooks M.; Walsh, Stephen J.; Bart, Henry L., Jr.; Cashner, Robert C.; Etnier, David A.; Freeman, Byron J.; Kuhajda, Bernard R.; Mayden, Richard L.; Robison, Henry W.; Ross, Stephen T.; Starnes, Wayne C.

    2000-01-01

    The Southeastern Fishes Council Technical Advisory Committee reviewed the diversity, distribution, and status of all native freshwater and diadromous fishes across 51 major drainage units of the southern United States. The southern United States supports more native fishes than any area of comparable size on the North American continent north of Mexico, but also has a high proportion of its fishes in need of conservation action. The review included 662 native freshwater and diadromous fishes and 24 marine fishes that are significant components of freshwater ecosystems. Of this total, 560 described, freshwater fish species are documented, and 49 undescribed species are included provisionally pending formal description. Described subspecies (86) are recognized within 43 species, 6 fishes have undescribed subspecies, and 9 others are recognized as complexes of undescribed taxa. Extinct, endangered, threatened, or vulnerable status is recognized for 28% (187 taxa) of southern freshwater and diadromous fishes. To date, 3 southern fishes are known to be extinct throughout their ranges, 2 are extirpated from the study region, and 2 others may be extinct. Of the extant southern fishes, 41 (6%) are regarded as endangered, 46 (7%) are regarded as threatened, and 101 (15%) are regarded as vulnerable. Five marine fishes that frequent fresh water are regarded as vulnerable. Our assessment represents a 75% increase in jeopardized southern fishes since 1989 and a 125% increase in 20 years. The trend for fishes in the southern United States is clear; jeopardized fishes are successively being moved from the vulnerable category to that of imminent threat of extinction.

  20. Ecosystem connectivity: anadromous fish migration linked to freshwater amphipods

    NASA Astrophysics Data System (ADS)

    Macavoy, S. E.; Fogel, M. L.; Fong, D.; Hanson, N.

    2009-12-01

    Anadromous fish migrate to coastal streams to spawn each spring and may transfer marine derived nutrients to oligotrophic tidal freshwater. River herring (Alosa sp) are the dominant anadromous genus in Virginia, USA. This study investigates whether marine nutrients derived by the spawning Alosa were incorporated into benthic invertebrates by using the stable isotopes of carbon and nitrogen. Spawning Alosa had higher δ13C and δ15N than resident freshwater omnivorous fishes (-18.5 and 13.9‰ versus -25.7 and 11.8‰). In a tidal stream supporting abundant spawning Alosa, significant 13C and 15N enrichment was observed among stream invertebrates, particularly in the amphipod Gammarus fasciatus, coincident with the Alosa spawning migration. Among G. fasciatus, δ13C increased from -28.5 to -26.0‰ between early and late April then fell to -28.1‰ in early June. A similar trend was observed in mayflies (Heptageniidae). In an adjacent tidal stream that did not support spawning Alosa, enrichment among invertebrates was not observed. Particulate organic matter and sediments from both streams remained 13C and 15N depleted during the Alosa spawning run (between -29 and -28‰, 0.5 and 3.0‰ respectively), suggesting that marine material was not present. Although marine organic material may have been incorporated into stream invertebrates, it did not become a substantial component of other ecosystem components measured.

  1. High prevalence of trypanosome co-infections in freshwater fishes.

    PubMed

    Grybchuk-Ieremenko, Anastasiia; Losev, Alexander; Kostygov, Alexei Yu; Lukeš, Julius; Yurchenko, Vyacheslav

    2014-12-01

    One thousand three hundred seventy three fish specimens of eight different species from the vicinity of Kyiv, Ukraine, were examined for the presence of trypanosomes and 921 individuals were found to be infected. The prevalence of infection ranged from 24% in freshwater bream, Abramis brama (Linnaeus), to 100% in spined loach, Cobitis 'taenia' Linnaeus. The level of parasitaemia also varied significantly between generally mild infections in pikeperch, Sander lucioperca (Linnaeus), and heavy ones in C. 'taenia'. In most cases the infections with trypanosomes were asymptomatic. Cases of co-infection with species of Trypanoplasma Laveran et Mesnil, 1901 were documented for five out of eight examined host species. Molecular analysis of the 18S rDNA sequences revealed that four hosts, namely northern pike, Esox lucius Linnaeus, freshwater bream, spined loach and European perch, Perca fluviatilis Linnaeus, were simultaneously infected with two different trypanosome species. Our findings advocate the view that to avoid the risk posed by mixed infections, subsequent molecular taxonomic studies should be performed on clonal lines derived from laboratory cultures of fish trypanosomes. PMID:25651690

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

    PubMed

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

    2016-04-01

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

  3. Can DNA barcoding accurately discriminate megadiverse Neotropical freshwater fish fauna?

    PubMed Central

    2013-01-01

    Background The megadiverse Neotropical freshwater ichthyofauna is the richest in the world with approximately 6,000 recognized species. Interestingly, they are distributed among only 17 orders, and almost 80% of them belong to only three orders: Characiformes, Siluriformes and Perciformes. Moreover, evidence based on molecular data has shown that most of the diversification of the Neotropical ichthyofauna occurred recently. These characteristics make the taxonomy and identification of this fauna a great challenge, even when using molecular approaches. In this context, the present study aimed to test the effectiveness of the barcoding methodology (COI gene) to identify the mega diverse freshwater fish fauna from the Neotropical region. For this purpose, 254 species of fishes were analyzed from the Upper Parana River basin, an area representative of the larger Neotropical region. Results Of the 254 species analyzed, 252 were correctly identified by their barcode sequences (99.2%). The main K2P intra- and inter-specific genetic divergence values (0.3% and 6.8%, respectively) were relatively low compared with similar values reported in the literature, reflecting the higher number of closely related species belonging to a few higher taxa and their recent radiation. Moreover, for 84 pairs of species that showed low levels of genetic divergence (<2%), application of a complementary character-based nucleotide diagnostic approach proved useful in discriminating them. Additionally, 14 species displayed high intra-specific genetic divergence (>2%), pointing to at least 23 strong candidates for new species. Conclusions Our study is the first to examine a large number of freshwater fish species from the Neotropical area, including a large number of closely related species. The results confirmed the efficacy of the barcoding methodology to identify a recently radiated, megadiverse fauna, discriminating 99.2% of the analyzed species. The power of the barcode sequences to identify

  4. Physiological basis for large differences in resistance to nitrite among freshwater and freshwater-acclimated euryhaline fishes.

    PubMed

    Tomasso, Joseph R; Grosell, Martin

    2005-01-01

    Uptake of environmental NO2- by most freshwater fishes occurs at the gills where NO2- is actively transported into the blood by the Cl- uptake pathway. Some freshwater fishes do not concentrate NO2- in their plasma, regardless of environmental NO2- exposure and exhibit a high degree of resistance to NO2-. Recent studies indicate that freshwater-adapted killifish (Fundulidae: Fundulus heteroclitus) and European eel (Anguillidae: Anguilla anguilla) have no or minimal Cl- uptake activity at the gills relative to most freshwater fishes; rather, Cl- requirements are met in other ways (probably dietary). We hypothesized that different rates of Cl- uptake by the gill may explain the observed differences in NO2- uptake and consequent toxicity among freshwater fishes. Cl- influx rates of channel catfish (Ictaluridae: Ictalurus punctatus), a species that concentrates NO2- in the plasma and is sensitive to NO2-, and bluegill (Centrarchidae: Lepomis macrochirus), a species that does not concentrate NO2- in the plasma and is resistant to NO2-, were determined over a range of environmental Cl- concentrations. Channel catfish actively transported chloride into the plasma (Km = 155.6+/-101.2 micromol/L Cl-; Jmax = 414.9+/-51.4 nmol/g/h; +/-SEM). In contrast, bluegill exhibited no observable Cl- uptake. We placed our results and previously reported results in a phylogenetic context and concluded that differences in Cl- uptake mechanisms among groups of freshwater fishes may explain, in large part, the wide range of sensitivity to environmental NO2-. NO2- uptake determinations may also prove to be an easy screening method when studying the phylogenetic distribution and nature of Cl- uptake mechanisms in the gills of fishes. PMID:15667081

  5. Interactions between water temperature and contaminant toxicity to freshwater fish.

    PubMed

    Patra, Ronald W; Chapman, John C; Lim, Richard P; Gehrke, Peter C; Sunderam, Ramasamy M

    2015-08-01

    Warming of freshwaters as a result of climate change is expected to have complex interactions with the toxicity of contaminants to aquatic organisms. The present study evaluated the effects of temperature on the acute toxicity of endosulfan, chlorpyrifos, and phenol to 3 warm water species of fish-silver perch, rainbowfish, and western carp gudgeon-and 1 cold water species, rainbow trout. Endosulfan was more toxic to silver perch at 30 °C and 35 °C than at 15 °C, 20 °C and 25 °C during short exposures of 24 h, but at 96 h, temperature had no effect on toxicity. Toxicity to rainbow trout increased with increasing temperature, whereas warm water species exhibited maximum toxicity at around 30 °C, decreasing again toward 35 °C. Chlorpyrifos became more toxic to all species with increasing temperature. Phenol toxicity to all species decreased at low to intermediate temperatures; but as temperatures increased further toward the upper thermal limit, phenol became more toxic. Increasing toxicity in the upper thermal range of cold water species may contribute to upstream range contraction in rivers with high toxicant loads. In contrast, warm water species may not exhibit a range shift within rivers as a result of interactions between temperature and toxicity. Catchment management to offset global warming at local scales may present opportunities to mitigate increased toxicity of contaminants to fish. PMID:26033197

  6. How restructuring river connectivity changes freshwater fish biodiversity and biogeography

    USGS Publications Warehouse

    Lynch, Heather L.; Grant, Evan H. Campbell; Muneepeerakul, Rachata; Arunachalam, Muthukumarasamy; Rodriguez-Iturbe, Ignacio; Fagan, William F.

    2011-01-01

    Interbasin water transfer projects, in which river connectivity is restructured via man-made canals, are an increasingly popular solution to address the spatial mismatch between supply and demand of fresh water. However, the ecological consequences of such restructuring remain largely unexplored, and there are no general theoretical guidelines from which to derive these expectations. River systems provide excellent opportunities to explore how network connectivity shapes habitat occupancy, community dynamics, and biogeographic patterns. We apply a neutral model (which assumes competitive equivalence among species within a stochastic framework) to an empirically derived river network to explore how proposed changes in network connectivity may impact patterns of freshwater fish biodiversity. Without predicting the responses of individual extant species, we find the addition of canals connecting hydrologically isolated river basins facilitates the spread of common species and increases average local species richness without changing the total species richness of the system. These impacts are sensitive to the parameters controlling the spatial scale of fish dispersal, with increased dispersal affording more opportunities for biotic restructuring at the community and landscape scales. Connections between isolated basins have a much larger effect on local species richness than those connecting reaches within a river basin, even when those within-basin reaches are far apart. As a result, interbasin canal projects have the potential for long-term impacts to continental-scale riverine communities.

  7. Prevalence of Ingested Fish Hooks in Freshwater Turtles from Five Rivers in the Southeastern United States

    PubMed Central

    Steen, David A.; Hopkins, Brittney C.; Van Dyke, James U.; Hopkins, William A.

    2014-01-01

    Freshwater turtles may ingest baited fish hooks because many are opportunistic scavengers. Although the ingestion of fish hooks is known to be a source of mortality in multiple vertebrate groups, the prevalence of hook ingestion by freshwater turtles has not been well studied. We trapped turtles from five rivers in the southeastern United States and used radiographs to examine over 600 individuals of four species. Depending on the species, sex, and age class, 0–33% of turtles contained ingested fish hooks. For some species, larger turtles were more likely to contain a fish hook than smaller individuals. Freshwater turtle demography suggests that even small increases in adult mortality may lead to population declines. If our study areas are representative of other aquatic systems that receive fishing pressure, this work likely identifies a potential conflict between a widespread, common recreational activity (i.e., fishing) and an imperiled taxonomic group. PMID:24621919

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  9. HEAVY METAL ACCUMULATION IN SEDIMENT AND FRESHWATER FISH IN U.S. ARCTIC LAKES

    EPA Science Inventory

    Metal concentrations in sediment and two species of freshwater fish (lake trout [Salvelinus namaycush], and grayling [Thymallus arcticus]} were examined in four Arctic lakes in Alaska. Concentrations of several metals were naturally high in the sediment relative to uncontaminated...

  10. Caryophyllidean tapeworms (Platyhelminthes: Eucestoda) from freshwater fishes in Japan.

    PubMed

    Scholz, T; Shimazu, T; Olson, P D; Nagasawa, K

    2001-01-01

    The following caryophyllidean tapeworms were found in freshwater fishes from Japan (species reported from Japan for the first time marked with an asterisk): family Caryophyllaeidae: Paracaryophyllaeus gotoi (Motomura, 1927) from Misgurnus anguillicaudatus (Cantor); Archigetes sieboldi Leuckart, 1878 from Pseudorasbora parva (Temminck et Schlegel) and Sarcocheilichthys variegatus microoculus Mori (new hosts); family Lytocestidae: *Caryophyllaeides ergensi Scholz, 1990 from Tribolodon hakuensis (Günther), T. ezoe Okada et Ikeda, Hemibarbus barbus (Temminck et Schlegel) and Chaenogobius sp. (new hosts); Khawia japonensis (Yamaguti, 1934) from Cyprinus carpio Linnaeus; K. sinensis Hsü, 1935 from H. barbus (new host) and C. carpio; *K. parva (Zmeev, 1936) from Carassius auratus langsdorfii Valenciennes in Cuvier et Valenciennes and Carassius sp. (new hosts); and *Atractolytocestus sagittatus (Kulakovskaya et Akhmerov, 1962) from C. carpio; family Capingentidae: *Breviscolex orientalis Kulakovskaya, 1962 from H. barbus (new host); and Caryophyllidea gen. sp. (probably Breviscolex orientalis) from C. carpio. The validity of C. ergensi, originally described from Leuciscus leuciscus baicalensis from Mongolia, is confirmed on the basis of an evaluation of extensive material from Japan. Atractolytocestus sagittatus (syn. Markevitschia sagittata) is tentatively considered a valid species, differing from the only congener, A. huronensis Anthony, 1958, in its considerably greater number of testes. PMID:11817451

  11. Effects of salinity on freshwater fishes in coastal plain drainages in the southeastern U.S.

    USGS Publications Warehouse

    Peterson, Mark S.; Meador, Michael R.

    1994-01-01

    This review focuses on the influence of salinity on freshwater fishes in coastal rivers and estuaries of the southeastern U.S. Influences of salinity on freshwater fish species can be explained partly through responses evidenced by behavior, physiology, growth, reproduction, and food habits during all aspects of life history. Factors influencing the rate of salinity change affect the community structure and dynamics of freshwater fishes in brackish environments. Our understanding of the relation between salinity and the life history of freshwater fishes is limited because little ecological research has been conducted in low-salinity habitats that we consider an “interface” between freshwater streams and the estuary proper. Much of the available data are descriptive in nature and describe best general patterns, but more specific studies are required to better determine the influence of salinity on freshwater fishes. Improved understanding of the influence of human-induced changes on the productivity and viability of these important systems will require a new research focus.

  12. The host effects of Gambusia affinis with an antibiotic-disrupted microbiome.

    PubMed

    Carlson, Jeanette M; Hyde, Embriette R; Petrosino, Joseph F; Manage, Ananda B W; Primm, Todd P

    2015-12-01

    While serving as critical tools against bacterial infections, antimicrobial therapies can also result in serious side effects, such as antibiotic-associated entercolitis. Recent studies utilizing next generation sequencing to generate community 16S gene profiles have shown that antibiotics can strongly alter community composition and deplete diversity. However, how these community changes in the microbiota are related to the host side effects is still unclear. We have used the freshwater Western mosquitofish (Gambusia affinis) as a tractable vertebrate model system to study host effects following exposure to a broad spectrum antibiotic, rifampicin. After 3days of exposure, the bacterial communities of the mucosal skin and gut microbiomes lost diversity and shifted composition. Compared to unexposed controls, treated fish were more susceptible to a specific pathogen, Edwardsiella ictaluri, yet displayed no survival differences when subjected to a polymicrobial water challenge of soil or feces. Treated fish were more susceptible to osmotic stress from NaCl, but not to the toxin nitrate. Treated fish failed to gain weight as well as controls over one month when fed a matched diet. Because of small sample sizes, pathogen susceptibility and weight gain differences were not statistically significant. This study provides supporting evidence in an experimental laboratory system that an antibiotic can have significant and persistent negative host effects, and provides for future study into the mechanisms of these effects. PMID:26475244

  13. The Microbiota of Freshwater Fish and Freshwater Niches Contain Omega-3 Fatty Acid-Producing Shewanella Species

    PubMed Central

    McGraw, Joseph E.; Jensen, Brittany J.; Bishop, Sydney S.; Lokken, James P.; Dorff, Kellen J.; Ripley, Michael P.; Munro, James B.

    2015-01-01

    Approximately 30 years ago, it was discovered that free-living bacteria isolated from cold ocean depths could produce polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) (20:5n-3) or docosahexaenoic acid (DHA) (22:6n-3), two PUFA essential for human health. Numerous laboratories have also discovered that EPA- and/or DHA-producing bacteria, many of them members of the Shewanella genus, could be isolated from the intestinal tracts of omega-3 fatty acid-rich marine fish. If bacteria contribute omega-3 fatty acids to the host fish in general or if they assist some bacterial species in adaptation to cold, then cold freshwater fish or habitats should also harbor these producers. Thus, we undertook a study to see if these niches also contained omega-3 fatty acid producers. We were successful in isolating and characterizing unique EPA-producing strains of Shewanella from three strictly freshwater native fish species, i.e., lake whitefish (Coregonus clupeaformis), lean lake trout (Salvelinus namaycush), and walleye (Sander vitreus), and from two other freshwater nonnative fish, i.e., coho salmon (Oncorhynchus kisutch) and seeforellen brown trout (Salmo trutta). We were also able to isolate four unique free-living strains of EPA-producing Shewanella from freshwater habitats. Phylogenetic and phenotypic analyses suggest that one producer is clearly a member of the Shewanella morhuae species and another is sister to members of the marine PUFA-producing Shewanella baltica species. However, the remaining isolates have more ambiguous relationships, sharing a common ancestor with non-PUFA-producing Shewanella putrefaciens isolates rather than marine S. baltica isolates despite having a phenotype more consistent with S. baltica strains. PMID:26497452

  14. The Microbiota of Freshwater Fish and Freshwater Niches Contain Omega-3 Fatty Acid-Producing Shewanella Species.

    PubMed

    Dailey, Frank E; McGraw, Joseph E; Jensen, Brittany J; Bishop, Sydney S; Lokken, James P; Dorff, Kellen J; Ripley, Michael P; Munro, James B

    2016-01-01

    Approximately 30 years ago, it was discovered that free-living bacteria isolated from cold ocean depths could produce polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) (20:5n-3) or docosahexaenoic acid (DHA) (22:6n-3), two PUFA essential for human health. Numerous laboratories have also discovered that EPA- and/or DHA-producing bacteria, many of them members of the Shewanella genus, could be isolated from the intestinal tracts of omega-3 fatty acid-rich marine fish. If bacteria contribute omega-3 fatty acids to the host fish in general or if they assist some bacterial species in adaptation to cold, then cold freshwater fish or habitats should also harbor these producers. Thus, we undertook a study to see if these niches also contained omega-3 fatty acid producers. We were successful in isolating and characterizing unique EPA-producing strains of Shewanella from three strictly freshwater native fish species, i.e., lake whitefish (Coregonus clupeaformis), lean lake trout (Salvelinus namaycush), and walleye (Sander vitreus), and from two other freshwater nonnative fish, i.e., coho salmon (Oncorhynchus kisutch) and seeforellen brown trout (Salmo trutta). We were also able to isolate four unique free-living strains of EPA-producing Shewanella from freshwater habitats. Phylogenetic and phenotypic analyses suggest that one producer is clearly a member of the Shewanella morhuae species and another is sister to members of the marine PUFA-producing Shewanella baltica species. However, the remaining isolates have more ambiguous relationships, sharing a common ancestor with non-PUFA-producing Shewanella putrefaciens isolates rather than marine S. baltica isolates despite having a phenotype more consistent with S. baltica strains. PMID:26497452

  15. Fishborne Trematode Metacercariae in Freshwater Fish from Guangxi Zhuang Autonomous Region, China

    PubMed Central

    Eom, Keeseon S.; Min, Duk-Young; Rim, Han-Jong; Hoang, Eui-Hyug; Yang, Yichao; Li, Xueming

    2009-01-01

    A survey was performed to investigate the infection status of fishborne trematode (FBT) metacercariae in freshwater fish from Guangxi Zhuang Autonomous Region, China. A total of 307 freshwater fish of 31 species were collected from 5 administrative regions of Guangxi Zhuang Autonomous Region. They were examined by artificial digestion method from July 2003 to August 2004. No metacercariae were detected in fish from Fusui-xian. In fish from Mashan-xian and a market in Nanning, 3 species of metacercariae, Haplorchis taichui, Haplorchis pumilio, and Centrocestus formosanus, were mainly detected. Metacercariae (8 in number) of Clonorchis sinensis were found in 1 Chanodichthys dabryi purchased from a market in Nanning. In fish from Yangshuo, Metagonimus yokogawai metacercariae were detected from all 18 fish species examined. Total 13 C. sinensis metacercariae were found in 3 out of 10 Hemibarbus maculatus from Yangshuo. All 7 Zacco platypus from Yangshuo were infected with 8-112 Echinochasmus perfoliatus metacercariae. In fish from Binyang-xian, H. pumilo metacercariae were mainly detected in all 5 fish species examined, and only 1 metacercaria of C. sinensis was found in a Hemiculter leucisculus. From the above results, it was confirmed that some species of freshwater fish play a role of second intermediate hosts for FBT in Guangxi Zhuang Autonomous Region, China. In particular, 4 species of intestinal flukes, M. yokogawai, H. taichui, H. pumilio, and C. formosanus, were prevalent in fish hosts, whereas C. sinensis metacercariae were detected only in 3 fish species. PMID:19724698

  16. Freshwater Fish Assemblage Patterns in Rhode Island Streams and Rivers (ESA)

    EPA Science Inventory

    Patterns in fish assemblages in streams and rivers can inform watershed and water management, yet these patterns are not well characterized for the U.S. state of Rhode Island. Here we relate freshwater fish data collected by the Rhode Island Department of Environmental Managemen...

  17. Use of an indigenous fish species, Fundulus zebrinus, in a mosquito abatement program: a field comparison with the mosquitofish, Gambusia affinis.

    PubMed

    Nelson, S M; Keenan, L C

    1992-09-01

    Studies were conducted relating mosquito production in small ponds to presence or absence of larvivorous fishes. Data collected showed that native killifish and introduced mosquitofish controlled mosquito larvae at the same level and support the use of indigenous fish species in mosquito abatement programs. PMID:1357089

  18. Residual levels of rare earth elements in freshwater and marine fish and their health risk assessment from Shandong, China.

    PubMed

    Yang, Luping; Wang, Xining; Nie, Hongqian; Shao, Lijun; Wang, Guoling; Liu, Yongjun

    2016-06-15

    The total concentrations of rare earth elements (ΣREE) were quantified in 251 samples from 10 common species of freshwater and marine fish in seventeen cities of Shandong, China. ΣREE obtained from the freshwater fish ranged from 34.0 to 37.9ngg(-1) (wet weight) and marine fish from 12.7 to 37.6ngg(-1). The ratio of LREE to HREE was 13.7:1 and 10:1 for freshwater and marine fish, respectively. This suggests that freshwater fish exhibit greater REE concentrations than marine fish and the biological effects of LREE are higher than HREE. Results revealed a similar REE distribution pattern between those fish and coastal sediments, abiding the "abundance law". The health risk assessment demonstrated the EDIs of REEs in fish were significantly lower than the ADI, indicating that the consumption of these fish presents little risk to human health. PMID:27016961

  19. Effects of low arsenic concentration exposure on freshwater fish in the presence of fluvial biofilms.

    PubMed

    Tuulaikhuu, Baigal-Amar; Bonet, Berta; Guasch, Helena

    2016-02-15

    Arsenic (As) is a highly toxic element and its carcinogenic effect on living organisms is well known. However, predicting real effects in the environment requires an ecological approach since toxicity is influenced by many environmental and biological factors. The purpose of this paper was to evaluate if environmentally-realistic arsenic exposure causes toxicity to fish. An experiment with four different treatments (control (C), biofilm (B), arsenic (+As) and biofilm with arsenic (B+As)) was conducted and each one included sediment to enhance environmental realism, allowing the testing of the interactive effects of biofilm and arsenic on the toxicity to fish. Average arsenic exposure to Eastern mosquitofish (Gambusia holbrooki) was 40.5 ± 7.5 μg/L for +As treatment and 34.4 ± 1.4 μg/L for B+As treatment for 56 days. Fish were affected directly and indirectly by this low arsenic concentration since exposure did not only affect fish but also the function of periphytic biofilms. Arsenic effects on the superoxide dismutase (SOD) and glutathione reductase (GR) activities in the liver of mosquitofish were ameliorated in the presence of biofilms at the beginning of exposure (day 9). Moreover, fish weight gaining was only affected in the treatment without biofilm. After longer exposure (56 days), effects of exposure were clearly seen. Fish showed a marked increase in the catalase (CAT) activity in the liver but the interactive influence of biofilms was not further observed since the arsenic-affected biofilm had lost its role in water purification. Our results highlight the interest and application of incorporating some of the complexity of natural systems in ecotoxicology and support the use of criterion continuous concentration (CCC) for arsenic lower than 150 μg/L and closer to the water quality criteria to protect aquatic life recommended by the Canadian government which is 5 μg As/L. PMID:26657392

  20. A sieving method for collecting the metacercariae of trematode parasites from freshwater fish.

    PubMed

    Fan, P C; Wu, C C; Huang, P; Yen, C W

    2002-03-01

    This study describes a sieving method for the collection of metacercariae from frozen (-20 degrees C) freshwater fish. Digested fish tissue is filtered through a series of sieves; the crude filtrate is then centrifuged. Centrifugation produces a sediment from which metacercariae can be removed. Half of the metracercariae that were obtained from the fish meat that had been frozen for 10 days (-20 degrees C) were dead; the other half were alive and some larvae were moving slowly. PMID:12118453

  1. Mosquitofish (Gambusia affinis) Preference and Behavioral Response to Animated Images of Conspecifics Altered in Their Color, Aspect Ratio, and Swimming Depth

    PubMed Central

    Polverino, Giovanni; Liao, Jian Cong; Porfiri, Maurizio

    2013-01-01

    Mosquitofish (Gambusia affinis) is an example of a freshwater fish species whose remarkable diffusion outside its native range has led to it being placed on the list of the world’s hundred worst invasive alien species (International Union for Conservation of Nature). Here, we investigate mosquitofish shoaling tendency using a dichotomous choice test in which computer-animated images of their conspecifics are altered in color, aspect ratio, and swimming level in the water column. Pairs of virtual stimuli are systematically presented to focal subjects to evaluate their attractiveness and the effect on fish behavior. Mosquitofish respond differentially to some of these stimuli showing preference for conspecifics with enhanced yellow pigmentation while exhibiting highly varying locomotory patterns. Our results suggest that computer-animated images can be used to understand the factors that regulate the social dynamics of shoals of Gambusia affinis. Such knowledge may inform the design of control plans and open new avenues in conservation and protection of endangered animal species. PMID:23342131

  2. Response of mosquitofish (Gambusia affinis) populations to seasonally unpredictable perturbations

    SciTech Connect

    Horn, M.J.; Stewart, A.J.

    1990-07-01

    Many questions remain unresolved about the linkages between life history attributes of fishes and the tactics that these organisms employ in response to environmental uncertainty. Such questions include (1). If a perturbation affects the entire ecosystem, what are the consequences for a given population of fish (2) What tactics can a fish employ to increase its chances of leaving offspring (3) Do fish respond differently to such perturbations depending on the season (4) How do these changes relate to the overall resilience of the population The research reported here was designed to address such questions. Mosquito fish (Gambusia affinis) populations in thirteen experimental ponds at Oak Ridge National Laboratory were sampled ten times between June 1988, and July 1989 in response to a series of chemical disturbances. During each sampling period the population size and total biomass of Gambusia in each pond was estimated using photographs and a length weight regression. Size-frequency histograms were used to examine seasonal and dose-related changes in population structure. Lipid content and reproductive allotment were measured for a series of fish from each pond on all dates to explore the energy allocation patterns at the individual. 106 refs., 38 figs., 16 tabs.

  3. Host specificity, pathogenicity, and mixed infections of trypanoplasms from freshwater fishes.

    PubMed

    Losev, Alexander; Grybchuk-Ieremenko, Anastasiia; Kostygov, Alexei Yu; Lukeš, Julius; Yurchenko, Vyacheslav

    2015-03-01

    This work summarizes the results of the 8-year study focused on Trypanoplasma sp. parasitizing freshwater fishes in the vicinity of Kyiv, Ukraine. Out of 570 fish specimens of 2 different species analyzed, 440 individuals were found to be infected. The prevalence of infection ranged from 24 % in Abramis brama Linnaeus (freshwater bream) to 100 % in Cobitis taenia Linnaeus (spined loach). The level of parasitemia also varied between moderate in freshwater bream and very high in spined loach. Interestingly, no clinical manifestations of trypanoplasmosis were observed even in extremely heavily infected C. taenia. We hypothesize that different species may differ in evolutionary timing allowing for reciprocal adaptation of the members of the "host-parasite" system. Molecular analysis of the 18S rRNA sequences revealed that several specimens were simultaneously infected with at least two different trypanoplasm species. To the best of our knowledge, this is the first report of the mixed infection with fish trypanoplasms. PMID:25544706

  4. Arsenic contamination in the freshwater fish ponds of Pearl River Delta: bioaccumulation and health risk assessment.

    PubMed

    Cheng, Zhang; Chen, Kun-Ci; Li, Kai-Bin; Nie, Xiang-Ping; Wu, Sheng Chun; Wong, Chris Kong-Chu; Wong, Ming-Hung

    2013-07-01

    This study investigated the extent of arsenic (As) contamination in five common species of freshwater fish (northern snakehead [Channa argus], mandrarin fish [Siniperca chuatsi], largemouth bass [Lepomis macrochirous], bighead carp [Aristichthys nobilis] and grass carp [Ctenopharyngodon idellus]) and their associated fish pond sediments collected from 18 freshwater fish ponds around the Pearl River Delta (PRD). The total As concentrations detected in fish muscle and sediment in freshwater ponds around the PRD were 0.05-3.01 mg kg(-1) wet weight (w. wt) and 8.41-22.76 mg kg(-1) dry weight (d. wt), respectively. In addition, the As content was positively correlated (p < 0.05) to total organic carbon (TOC) contents in sediments. Biota sediment accumulation factor (BSAF) showed that omnivorous fish and zooplankton accumulated higher concentrations of heavy metals from the sediment than carnivorous fish. In addition, feeding habits of fish also influence As accumulation in different fish species. In this study, two typical food chains of the aquaculture ponds were selected for investigation: (1) omnivorous food chain (zooplankton, grass carp and bighead carp) and (2) predatory food chain (zooplankton, mud carp and mandarin fish). Significant linear relationships were obtained between log As and δ (15)N. The slope of the regression (-0.066 and -0.078) of the log transformed As concentrations and δ (15)N values, as biomagnifications power, indicated there was no magnification or diminution of As from lower trophic levels (zooplankton) to fish in the aquaculture ponds. Consumption of largemouth bass, northern snakehead and bighead carp might impose health risks of Hong Kong residents consuming these fish to the local population, due to the fact that its cancer risk (CR) value exceeded the upper limit of the acceptable risk levels (10(-4)) stipulated by the USEPA. PMID:23247527

  5. Fishborne Trematode Metacercariae Detected in Freshwater Fish from Vientiane Municipality and Savannakhet Province, Lao PDR

    PubMed Central

    Rim, Han-Jong; Yong, Tai-Soon; Eom, Keeseon S.; Chai, Jong-Yil; Min, Duk-Young; Lee, Soon-Hyung; Hoang, Eui-Hyug; Phommasack, Bounlay; Insisengmay, Sithat

    2008-01-01

    Freshwater fish from Vientiane Municipality and Savannakhet Province, Lao PDR were examined by the muscle compression and artificial digestion methods to know the infection status with trematode metacercariae. In the fish from Savannakhet, 2 species of metacercariae, Opisthorchis viverrini and Haplorchis taichui, were detected. O. viverrini metacercariae were found in 6 species of fish, Puntius brevis, Hampala dispar, Esomus metallicus, Mystacoleucus marginatus, Puntioplites falcifer, and Cyclocheilichthys armatus. H. taichui metacercariae were detected in 3 species of fish, P. brevis, P. falcifer, and M. marginatus. In the fish from Vientiane, 4 species of metacercariae, O. viverrini, H. taichui, Haplorchis yokogawai, and Centrocestus formosanus, were detected. Among them, O. viverrini metacercariae were found in 7 species of fish, Onychostoma elongatum, C. armatus, H. dispar, P. brevis, Cyclocheilichthys repasson, Osteochilus hasseltii, and Hypsibarbus lagleri. The metacercariae of H. taichui were detected in 6 species of fish, C. repasson, O. elongatum, C. armatus, H. dispar, Labiobarbus leptocheila, and Cirrhinus molitorella. The metacercariae of H. yokogawai were found in 9 species of fish, C. repasson, O. elongatum, C. armatus, H. dispar, Labiobarbus leptocheila, O. hasseltii. C. molitorella, Hypsibarbus wetmorei, and H. lagleri. The metacercariae of C. formosanus were detected in 4 species of fish, C. repasson, P. brevis, O. hasseltii, and C. molitorella. From these results, it is confirmed that fishborne trematode metacercariae, i.e. O. viverrini, H. taichui, H. yokogawai and C. formosanus, are prevalent in various species of freshwater fish from Savannakhet Province and Vientiane Municipality, Lao PDR. PMID:19127332

  6. Research on marine and freshwater fish identification model based on hyper-spectral imaging technology

    NASA Astrophysics Data System (ADS)

    Fu, Yan; Guo, Pei-yuan; Xiang, Ling-zi; Bao, Man; Chen, Xing-hai

    2013-08-01

    With the gradually mature of hyper spectral image technology, the application of the meat nondestructive detection and recognition has become one of the current research focuses. This paper for the study of marine and freshwater fish by the pre-processing and feature extraction of the collected spectral curve data, combined with BP network structure and LVQ network structure, a predictive model of hyper spectral image data of marine and freshwater fish has been initially established and finally realized the qualitative analysis and identification of marine and freshwater fish quality. The results of this study show that hyper spectral imaging technology combined with the BP and LVQ Artificial Neural Network Model can be used for the identification of marine and freshwater fish detection. Hyper-spectral data acquisition can be carried out without any pretreatment of the samples, thus hyper-spectral imaging technique is the lossless, high- accuracy and rapid detection method for quality of fish. In this study, only 30 samples are used for the exploratory qualitative identification of research, although the ideal study results are achieved, we will further increase the sample capacity to take the analysis of quantitative identification and verify the feasibility of this theory.

  7. Vectors of invasions in freshwater invertebrates and fishes

    USGS Publications Warehouse

    Fuller, Pam L.

    2015-01-01

    Without human assistance, the terrestrial environment and oceans represent barriers to the dispersal of freshwater aquatic organisms. The ability to overcome such barriers depends on the existence of anthropogenic vectors that can transport live organisms to new areas, and the species’ biology to survive the transportation and transplantation into the new environment (Johnson et al., 2006).

  8. Climate change vulnerability of native and alien freshwater fishes of California: a systematic assessment approach.

    PubMed

    Moyle, Peter B; Kiernan, Joseph D; Crain, Patrick K; Quiñones, Rebecca M

    2013-01-01

    Freshwater fishes are highly vulnerable to human-caused climate change. Because quantitative data on status and trends are unavailable for most fish species, a systematic assessment approach that incorporates expert knowledge was developed to determine status and future vulnerability to climate change of freshwater fishes in California, USA. The method uses expert knowledge, supported by literature reviews of status and biology of the fishes, to score ten metrics for both (1) current status of each species (baseline vulnerability to extinction) and (2) likely future impacts of climate change (vulnerability to extinction). Baseline and climate change vulnerability scores were derived for 121 native and 43 alien fish species. The two scores were highly correlated and were concordant among different scorers. Native species had both greater baseline and greater climate change vulnerability than did alien species. Fifty percent of California's native fish fauna was assessed as having critical or high baseline vulnerability to extinction whereas all alien species were classified as being less or least vulnerable. For vulnerability to climate change, 82% of native species were classified as highly vulnerable, compared with only 19% for aliens. Predicted climate change effects on freshwater environments will dramatically change the fish fauna of California. Most native fishes will suffer population declines and become more restricted in their distributions; some will likely be driven to extinction. Fishes requiring cold water (<22°C) are particularly likely to go extinct. In contrast, most alien fishes will thrive, with some species increasing in abundance and range. However, a few alien species will likewise be negatively affected through loss of aquatic habitats during severe droughts and physiologically stressful conditions present in most waterways during summer. Our method has high utility for predicting vulnerability to climate change of diverse fish species. It

  9. Distinguishing between invasions and habitat changes as drivers of diversity loss among California's freshwater fishes.

    PubMed

    Light, Theo; Marchetti, Michael P

    2007-04-01

    Many of California's native populations of freshwater fish are in serious decline, as are freshwater faunas worldwide. Habitat loss and alteration, hydrologic modification, water pollution, and invasions have been identified as major drivers of these losses. Because these potential causes of decline are frequently correlated, it is difficult to separate direct from indirect effects of each factor and to appropriately rank their importance for conservation action. Recently a few authors have questioned the conservation significance of invasions, suggesting that they are "passengers" rather than "drivers" of ecological change. We compiled an extensive, watershed-level data set of fish presence and conservation status, land uses, and hydrologic modifications in California and used an information theoretic approach (Akaike's information criterion, AIC) and path analysis to evaluate competing models of native fish declines. Hydrologic modification (impoundments and diversions), invasions, and proportion of developed land were all predictive of the number of extinct and at-risk native fishes in California watersheds in the AIC analysis. Although nonindigenous fish richness was the best single predictor (after native richness) of fishes of conservation concern, the combined ranking of models containing hydrologic modification variables was slightly higher than that of models containing nonindigenous richness. Nevertheless, the path analysis indicated that the effects of both hydrologic modification and development on fishes of conservation concern were largely indirect, through their positive effects on nonindigenous fish richness. The best-fitting path model was the driver model, which included no direct effects of abiotic disturbance on native fish declines. Our results suggest that, for California freshwater fishes, invasions are the primary direct driver of extinctions and population declines, whereas the most damaging effect of habitat alteration is the tendency of

  10. Climate Change Vulnerability of Native and Alien Freshwater Fishes of California: A Systematic Assessment Approach

    PubMed Central

    Moyle, Peter B.; Kiernan, Joseph D.; Crain, Patrick K.; Quiñones, Rebecca M.

    2013-01-01

    Freshwater fishes are highly vulnerable to human-caused climate change. Because quantitative data on status and trends are unavailable for most fish species, a systematic assessment approach that incorporates expert knowledge was developed to determine status and future vulnerability to climate change of freshwater fishes in California, USA. The method uses expert knowledge, supported by literature reviews of status and biology of the fishes, to score ten metrics for both (1) current status of each species (baseline vulnerability to extinction) and (2) likely future impacts of climate change (vulnerability to extinction). Baseline and climate change vulnerability scores were derived for 121 native and 43 alien fish species. The two scores were highly correlated and were concordant among different scorers. Native species had both greater baseline and greater climate change vulnerability than did alien species. Fifty percent of California’s native fish fauna was assessed as having critical or high baseline vulnerability to extinction whereas all alien species were classified as being less or least vulnerable. For vulnerability to climate change, 82% of native species were classified as highly vulnerable, compared with only 19% for aliens. Predicted climate change effects on freshwater environments will dramatically change the fish fauna of California. Most native fishes will suffer population declines and become more restricted in their distributions; some will likely be driven to extinction. Fishes requiring cold water (<22°C) are particularly likely to go extinct. In contrast, most alien fishes will thrive, with some species increasing in abundance and range. However, a few alien species will likewise be negatively affected through loss of aquatic habitats during severe droughts and physiologically stressful conditions present in most waterways during summer. Our method has high utility for predicting vulnerability to climate change of diverse fish species. It

  11. TOXIC EFFECT OF WATER SOLUBLE POLLUTANTS ON FRESHWATER FISH

    EPA Science Inventory

    Studies of the effect of inorganic and organic mercury on trout indicated that uptake was primarily via the gills in non-feeding fish. Organic mercury entered fish at a faster rate than inorganic mercury. Exposure of trout to 10 micrograms Hg/l (methyl form) had no effect on the ...

  12. Patterns of Distribution of the Helminth Parasites of Freshwater Fishes of Mexico

    PubMed Central

    Quiroz-Martínez, Benjamín; Salgado-Maldonado, Guillermo

    2013-01-01

    In order to draw patterns in helminth parasite composition and species richness in Mexican freshwater fishes we analyse a presence-absence matrix representing every species of adult helminth parasites of freshwater fishes from 23 Mexican hydrological basins. We examine the distributional patterns of the helminth parasites with regard to the main hydrological basins of the country, and in doing so we identify areas of high diversity and point out the biotic similarities and differences among drainage basins. Our dataset allows us to evaluate the relationships among drainage basins in terms of helminth diversity. This paper shows that the helminth fauna of freshwater fishes of Mexico can characterise hydrological basins the same way as fish families do, and that the basins of south-eastern Mexico are home to a rich, predominantly Neotropical, helminth fauna whereas the basins of the Mexican Highland Plateau and the Nearctic area of Mexico harbour a less diverse Nearctic fauna, following the same pattern of distribution of their fish host families. The composition of the helminth fauna of each particular basin depends on the structure of the fish community rather than on the limnological characteristics and geographical position of the basin itself. This work shows distance decay of similarity and a clear linkage between host and parasite distributions. PMID:23359347

  13. UPTAKE AND DEPURATION STUDIES OF PCDDS AND PCDFS IN FRESHWATER FISH

    EPA Science Inventory

    The bioavailability of PCDD/PCDFs from municipal incinerator fly ash and sediment to freshwater fish has been studied. A preference to selectively bioaccumulate PCDD/PCDF isomers substituted in the 2,3,7, and 8 positions was observed. The depuration half life of 2,3,7,8-TCDD from...

  14. HABITAT USE OF TWENTY-FIVE COMMON SPECIES OF OREGON FRESHWATER FISHES

    EPA Science Inventory

    This study had two objectives. he first was to determine the use of the physical habitat by the 25 most common native freshwater fishes of Oregon, and the second was to evaluate the use of a large computer database of museum records in the determination. he database encompasses 2...

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

    PubMed

    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. PMID:21574555

  16. Global-Scale Relationships between Colonization Ability and Range Size in Marine and Freshwater Fish

    PubMed Central

    Strona, Giovanni; Galli, Paolo; Montano, Simone; Seveso, Davide; Fattorini, Simone

    2012-01-01

    Although fish range sizes are expected to be associated with species dispersal ability, several studies failed to find a clear relationship between range size and duration of larval stage as a measure of dispersal potential. We investigated how six characteristics of the adult phase of fishes (maximum body length, growth rate, age at first maturity, life span, trophic level and frequency of occurrence) possibly associated with colonization ability correlate with range size in both freshwater and marine species at global scale. We used more than 12 million point records to estimate range size of 1829 freshwater species and 10068 marine species. As measures of range size we used both area of occupancy and extent of occurrence. Relationships between range size and species traits were assessed using Canonical Correlation Analysis. We found that frequency of occurrence and maximum body length had a strong influence on range size measures, which is consistent with patterns previously found (at smaller scales) in several other taxa. Freshwater and marine fishes showed striking similarities, suggesting the existence of common mechanisms regulating fish biogeography in the marine and freshwater realms. PMID:23185338

  17. HISTOPATHOLOGIC BIOMARKERS IN FERAL FRESHWATER FISH POPULATIONS EXPOSED TO DIFFERENT TYPES OF CONTAMINANT STRESS. (R825433)

    EPA Science Inventory

    Histopathologic alterations of gill, liver, and spleen were studied in feral fish from three freshwater ecosystems that experience different types of contaminant stress. East Fork Poplar Creek (EFPC), a third-order stream in East Tennessee, receives point source discharges of ...

  18. Biogeography of Iberian freshwater fishes revisited: The roles of historical versus contemporary constraints

    USGS Publications Warehouse

    Filipe, Ana F.; Araújo, Miguel B.; Doadrio, Ignacio; Angermeier, Paul L.; Collares-Pereira, Maria J.

    2009-01-01

    Main conclusions The results support the hypothesis that historical factors exert greater constraints on native freshwater fish assemblages in the Iberian Peninsula than do current environmental factors. After examining patterns of assemblage variation across space, as evidenced by the biogeographical provinces, we discuss the likely dispersal and speciation events that underlie these patterns. 

  19. CONDITIONS FOR COEXISTENCE OF FRESHWATER MUSSEL SPECIES VIA PARTITIONING OF FISH HOST RESOURCES

    EPA Science Inventory

    Riverine freshwater mussel species can be found in highly diverse communities where many similar species coexist. Mussel species potentially compete for food and space as adults, and for fish host resources during the larval (glochidial) stage. Resource partitioning at the larv...

  20. Draft Genome Sequence of the Radioresistant Bacterium Deinococcus grandis, Isolated from Freshwater Fish in Japan

    PubMed Central

    Onodera, Takefumi; Omoso, Kota; Takeda-Yano, Kiyoko; Katayama, Takeshi; Oono, Yutaka; Narumi, Issay

    2016-01-01

    Deinococcus grandis is a radioresistant bacterium isolated from freshwater fish in Japan. Here we reported the draft genome sequence of D. grandis (4.1 Mb), which will be useful for elucidating the common principles of radioresistance in Deinococcus species through the comparative analysis of genomic sequences. PMID:26868384

  1. Global-scale relationships between colonization ability and range size in marine and freshwater fish.

    PubMed

    Strona, Giovanni; Galli, Paolo; Montano, Simone; Seveso, Davide; Fattorini, Simone

    2012-01-01

    Although fish range sizes are expected to be associated with species dispersal ability, several studies failed to find a clear relationship between range size and duration of larval stage as a measure of dispersal potential. We investigated how six characteristics of the adult phase of fishes (maximum body length, growth rate, age at first maturity, life span, trophic level and frequency of occurrence) possibly associated with colonization ability correlate with range size in both freshwater and marine species at global scale. We used more than 12 million point records to estimate range size of 1829 freshwater species and 10068 marine species. As measures of range size we used both area of occupancy and extent of occurrence. Relationships between range size and species traits were assessed using Canonical Correlation Analysis. We found that frequency of occurrence and maximum body length had a strong influence on range size measures, which is consistent with patterns previously found (at smaller scales) in several other taxa. Freshwater and marine fishes showed striking similarities, suggesting the existence of common mechanisms regulating fish biogeography in the marine and freshwater realms. PMID:23185338

  2. Assessing Essential Fish Habitat in Freshwater Environments Using Otolith Chemistry: Spring River, AR.

    NASA Astrophysics Data System (ADS)

    Bickford, N. A.; Hamilton, B.; Hannigan, R. E.

    2002-12-01

    The identification of essential fish habitat within freshwater systems is critical to the management of the game fish populations. In order to accurately assess habitat we investigated the physical and chemical hydrological controls on game fish abundances and distributions with the 92-km reach of the Spring River of Arkansas. The hydrology of the river was integrated in to the chemical analyses of otolith chemistry of game fish from habitats throughout the river. Identified spatial and temporal variations in metal concentration within the Spring River are an important factor in the recognition of essential fish habitat. In the Spring River, where spatial and temporal metal concentration variations are significant, otolith chemistry has the potential to serve as a marker of essential habitat in much the same way as in estuarine and marine settings. Using otolith chemistry to identify essential habitat in freshwater systems has the potential to revolutionize ecological management strategies. Fish otolith chemistry shows both inter-species variations and spatial variations. Spatial variations in the otolith chemistry as recorded over the life of the fish allow identification of the nursery habitat and feeding range of game fish. Using otolith chemistry, particularly variations in trace element composition rather than the traditional major element ratios (i.e., Mg/Ca), we are able to identify essential habitats and provide managers data needed for conservation and preservation of these habitats.

  3. FishTraits: a database of ecological and life-history traits of freshwater fishes of the United States

    USGS Publications Warehouse

    Frimpong, Emmanuel A.; Angermeier, Paul L.

    2009-01-01

    The need for integrated and widely accessible sources of species traits data to facilitate studies of ecology, conservation, and management has motivated development of traits databases for various taxa. In spite of the increasing number of traits-based analyses of freshwater fishes in the United States, no consolidated database of traits of this group exists publicly, and much useful information on these species is documented only in obscure sources. The largely inaccessible and unconsolidated traits information makes large-scale analysis involving many fishes and/or traits particularly challenging. We have compiled a database of > 100 traits for 809 (731 native and 78 nonnative) fish species found in freshwaters of the conterminous United States, including 37 native families and 145 native genera. The database, named Fish Traits, contains information on four major categories of traits: (1) trophic ecology; (2) body size, reproductive ecology, and life history; (3) habitat preferences; and (4) salinity and temperature tolerances. Information on geographic distribution and conservation status was also compiled. The database enhances many opportunities for conducting research on fish species traits and constitutes the first step toward establishing a central repository for a continually expanding set of traits of North American fishes.

  4. FishTraits: a database of ecological and life-history traits of freshwater fishes of the United States

    USGS Publications Warehouse

    Angermeier, Paul L.; Frimpong, Emmanuel A.

    2011-01-01

    The need for integrated and widely accessible sources of species traits data to facilitate studies of ecology, conservation, and management has motivated development of traits databases for various taxa. In spite of the increasing number of traits-based analyses of freshwater fishes in the United States, no consolidated database of traits of this group exists publicly, and much useful information on these species is documented only in obscure sources. The largely inaccessible and unconsolidated traits information makes large-scale analysis involving many fishes and/or traits particularly challenging. We have compiled a database of > 100 traits for 809 (731 native and 78 nonnative) fish species found in freshwaters of the conterminous United States, including 37 native families and 145 native genera. The database, named Fish Traits, contains information on four major categories of traits: (1) trophic ecology; (2) body size, reproductive ecology, and life history; (3) habitat preferences; and (4) salinity and temperature tolerances. Information on geographic distribution and conservation status was also compiled. The database enhances many opportunities for conducting research on fish species traits and constitutes the first step toward establishing a central repository for a continually expanding set of traits of North American fishes.

  5. Accidental Bait: Do Deceased Fish Increase Freshwater Turtle Bycatch in Commercial Fyke Nets?

    NASA Astrophysics Data System (ADS)

    Larocque, Sarah M.; Watson, Paige; Blouin-Demers, Gabriel; Cooke, Steven J.

    2012-07-01

    Bycatch of turtles in passive inland fyke net fisheries has been poorly studied, yet bycatch is an important conservation issue given the decline in many freshwater turtle populations. Delayed maturity and low natural adult mortality make turtles particularly susceptible to population declines when faced with additional anthropogenic adult mortality such as bycatch. When turtles are captured in fyke nets, the prolonged submergence can lead to stress and subsequent drowning. Fish die within infrequently checked passive fishing nets and dead fish are a potential food source for many freshwater turtles. Dead fish could thus act as attractants and increase turtle captures in fishing nets. We investigated the attraction of turtles to decomposing fish within fyke nets in eastern Ontario. We set fyke nets with either 1 kg of one-day or five-day decomposed fish, or no decomposed fish in the cod-end of the net. Decomposing fish did not alter the capture rate of turtles or fish, nor did it alter the species composition of the catch. Thus, reducing fish mortality in nets using shorter soak times is unlikely to alter turtle bycatch rates since turtles were not attracted by the dead fish. Interestingly, turtle bycatch rates increased as water temperatures did. Water temperature also influences turtle mortality by affecting the duration turtles can remain submerged. We thus suggest that submerged nets to either not be set or have reduced soak times in warm water conditions (e.g., >20 °C) as turtles tend to be captured more frequently and cannot withstand prolonged submergence.

  6. The global status of freshwater fish age validation studies and a prioritization framework for future research

    USGS Publications Warehouse

    Pope, Kevin L.; Hamel, Martin J.; Pegg, Mark A.; Spurgeon, Jonathan J.

    2016-01-01

    Age information derived from calcified structures is commonly used to estimate recruitment, growth, and mortality for fish populations. Validation of daily or annual marks on age structures is often assumed, presumably due to a lack of general knowledge concerning the status of age validation studies. Therefore, the current status of freshwater fish age validation studies was summarized to show where additional effort is needed, and increase the accessibility of validation studies to researchers. In total, 1351 original peer-reviewed articles were reviewed from freshwater systems that studied age in fish. Periodicity and age validation studies were found for 88 freshwater species comprising 21 fish families. The number of age validation studies has increased over the last 30 years following previous calls for more research; however, few species have validated structures spanning all life stages. In addition, few fishes of conservation concern have validated ageing structures. A prioritization framework, using a combination of eight characteristics, is offered to direct future age validation studies and close the validation information gap. Additional study, using the offered prioritization framework, and increased availability of published studies that incorporate uncertainty when presenting research results dealing with age information are needed.

  7. Toxicity of 33NCS (3'-chloro-3-nitrosalicylanilide) to freshwater fish and sea lampreys

    USGS Publications Warehouse

    Marking, Leif L.; King, Everett L.; Walker, Charles R.; Howell, John H.

    1970-01-01

    The chemical 33NCS (3'-chloro-3-nitrosalicylanilide) was evaluated as a fish control agent and as a larvicide for sea lampreys at the Fish Control Laboratories of the Bureau of Sport Fisheries and Wildlife and the Hammond Bay Biological Station of the Bureau of Commercial Fisheries. The chemical is rapidly toxic to many species. Sea lampreys, bowfin, and channel catfish are the most sensitive species. Carp are more sensitive than trouts or sunfishes. Use of 33NCS in selective control of freshwater fishes or sea lampreys requires precise control because its toxicity is strongly influenced by variations in water quality.

  8. Prevalence of Zoonotic Trematode Metacercariae in Freshwater Fish from Gangwon-do, Korea

    PubMed Central

    Cho, Shin-Hyeong; Lee, Won-Ja; Kim, Tong-Soo; Seok, Won-Seok; Lee, Taejoon; Jeong, Kyungjin; Na, Byoung-Kuk

    2014-01-01

    The infection status of zoonotic trematode metacercariae was investigated in a total of 2,293 freshwater fish collected from 11 rivers or streams in 9 administrative regions of Gangwon-do, Korea for 5 years (2009-2013). All fish were collected by netting methods and examined using the artificial digestion methods. Clonorchis sinensis metacercariae were detected in 4 fish species, i.e., Pungtungia herzi, Squalidus japonicus coreanus, Acheilognathus rhombeus, and Ladislabia taczanowskii, from only Hantangang in Cheorwon-gun. Metagonimus spp. metacercariae were found in 1,154 (50.3%) fish and their average number per infected fish was 55.8. Among the positive fish species, especially Tribolodon hakonensis from Namdaecheon in Yangyang-gun and Plecoglossus altivelis from Osipcheon in Samcheok-si were most heavily infected. Centrocestus armatus metacercariae were detected in 611 (26.7%) fish and the average metacercarial burden per infected fish was 1,032. Two chub species, Zacco platypus and Zacco temminckii were highly and heavily infected with C. armatus metacercariae in almost all regions surveyed. Echinostoma spp. metacercariae were also found in 24 fish from a few localities, but their numbers per fish infected were very low. From the above results, it is confirmed that the metacercariae of intestinal flukes, especially Metagonimus spp. and C. armatus, were heavily infected, while C. sinensis metacercariae were rarely found in fish from Gangwon-do, Korea. PMID:25246719

  9. Prevalence of zoonotic trematode metacercariae in freshwater fish from Gangwon-do, Korea.

    PubMed

    Cho, Shin-Hyeong; Lee, Won-Ja; Kim, Tong-Soo; Seok, Won-Seok; Lee, Taejoon; Jeong, Kyungjin; Na, Byoung-Kuk; Sohn, Woon-Mok

    2014-08-01

    The infection status of zoonotic trematode metacercariae was investigated in a total of 2,293 freshwater fish collected from 11 rivers or streams in 9 administrative regions of Gangwon-do, Korea for 5 years (2009-2013). All fish were collected by netting methods and examined using the artificial digestion methods. Clonorchis sinensis metacercariae were detected in 4 fish species, i.e., Pungtungia herzi, Squalidus japonicus coreanus, Acheilognathus rhombeus, and Ladislabia taczanowskii, from only Hantangang in Cheorwon-gun. Metagonimus spp. metacercariae were found in 1,154 (50.3%) fish and their average number per infected fish was 55.8. Among the positive fish species, especially Tribolodon hakonensis from Namdaecheon in Yangyang-gun and Plecoglossus altivelis from Osipcheon in Samcheok-si were most heavily infected. Centrocestus armatus metacercariae were detected in 611 (26.7%) fish and the average metacercarial burden per infected fish was 1,032. Two chub species, Zacco platypus and Zacco temminckii were highly and heavily infected with C. armatus metacercariae in almost all regions surveyed. Echinostoma spp. metacercariae were also found in 24 fish from a few localities, but their numbers per fish infected were very low. From the above results, it is confirmed that the metacercariae of intestinal flukes, especially Metagonimus spp. and C. armatus, were heavily infected, while C. sinensis metacercariae were rarely found in fish from Gangwon-do, Korea. PMID:25246719

  10. Pre-anthropocene mercury residues in North American freshwater fish.

    PubMed

    Hope, Bruce K; Louch, Jeff

    2014-04-01

    Mercury (Hg) has been entering the environment from both natural and anthropogenic sources for millennia, and humans have been influencing its environmental transport and fate from well before the Industrial Revolution. Exposure to Hg (as neurotoxic monomethylmercury [MeHg]) occurs primarily through consumption of finfish, shellfish, and marine mammals, and regulatory limits for MeHg concentrations in fish tissue have steadily decreased as information on its health impacts has become available. These facts prompted us to consider 2 questions: 1) What might the MeHg levels in fish tissue have been in the pre-Anthropocene, before significant human impacts on the environment? and 2) How would these pre-Anthropocene levels have compared with current regulatory criteria for MeHg residues in fish tissue? We addressed the first question by estimating pre-Anthropocene concentrations of MeHg in the tissues of prey and predatory fish with an integrated Hg speciation, transport, fate, and food web model (SERAFM), using estimated Hg concentrations in soil, sediment, and atmospheric deposition before the onset of significant human activity (i.e., ≤2000 BCE). Model results show MeHg residues in fish varying depending on the characteristics of the modeled water body, which suggests that Hg in fish tissue is best considered at the scale of individual watersheds or water bodies. We addressed the second question by comparing these model estimates with current regulatory criteria and found that MeHg residues in predatory (but not prey) fish could have approached or exceeded these criteria in some water bodies during the pre-Anthropocene. This suggests that the possibility of naturally occurring levels of Hg in fish below which it is not possible to descend, regardless of where those levels stand with respect to current regulatory limits. Risk management decisions made under these circumstances have the potential to be ineffectual, frustrating, and costly for decision makers and

  11. Concentrations of microcystins in tissues of several fish species from freshwater reservoirs and ponds.

    PubMed

    Kopp, Radovan; Palíková, Miroslava; Adamovský, Ondřej; Ziková, Andrea; Navrátil, Stanislav; Kohoutek, Jiří; Mareš, Jan; Bláha, Luděk

    2013-12-01

    The aim of this study is to summarise the determination of concentrations of microcystins (MCs) in muscle and liver of freshwater fish species caught in stagnant waters of the Czech Republic. Within the years 2007-2009, 351 muscle samples and 291 liver samples of 16 freshwater fish species derived from four fishponds, and four water reservoirs were analysed. MCs were detected in 53 liver samples. The highest concentrations of microcystins were determined in liver samples of carnivorous fish species; 50.3 ng/g of fresh weight (FW) in perch (Perca fluviatilis) and 22.7 ng/g FW in pikeperch (Sander lucioperca). MCs in liver were detected in other five fish species; asp (Aspius aspius), pike (Esox lucius), common carp (Cyprinus carpio), grass carp (Ctenopharyngodon idella) and European eel (Anguilla anguilla). Concentrations of MCs in liver of nine fish species (European bream, whitefish, tench, silver carp, European catfish, roach, chub, crucian carp and rudd) were below the detection limit of 1.2-5.4 ng/g FW for different MC congeners. However, the concentrations of MCs in all muscle samples were below the detection limit. The assessment of MCs concentrations might be influenced by the detection method used. Due to the concentrations of MCs being below the detection limit in muscle samples of all fish species analysed, it seems that there might be a low potential threat for human health in case of fish muscle consumption. PMID:23756815

  12. [Overview of the artificial enhancement and release of endemic freshwater fish in China].

    PubMed

    Yang, Jun-Xing; Pan, Xiao-Fu; Chen, Xiao-Yong; Wang, Xiao-Ai; Zhao, Ya-Peng; Li, Jian-You; Li, Zai-Yun

    2013-08-01

    Due to declining fishery resources and the growing development of conservation aquaculture, artificial freshwater fish enhancement and releasing have begun to replace traditional means of recovering endemic and rare fish populations. Artificial proliferation can be beneficial both to endemic fish conservation and technical bottleneck breakthroughs. This overview presents a review of the latest research and the underlying principles behind the conservation implementation processes, as well as the research status of artificial enhancement and release of endangered freshwater fish species in China, such as Mylopharyngodon piceus, Ctenopharyngodon idellus, Hypophthalmichthys molitrix, H. nobilis, Acipenser sinensis, Myxocyprinus asiaticus, and Sinocyclocheilus grahami. The overview also presents evolutionarily significant units, sperm and egg quality, and cryopreservation technologies and cell cultures used in artificial enhancement and release, which help standardize genetic management and minimize the genetic differences between hatched and wild populations. Monitoring fish from cultivation to release is essential to evaluating wild population recovery and adjusting recovery plans. Moreover, the remaining problems of artificial releases are discussed in-depth, touching on issues such as the limitations of domestic hatching, the base number of wild populations necessary to the environment, the proper size at which to release juveniles' into the environment, the geographic confusion of populations, the contradictions in commercial fish selection and fish conservation, and "exotic species" invasion. PMID:23913882

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

    USGS Publications Warehouse

    Rashleigh, B.; DeAngelis, D.L.

    2007-01-01

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

  14. A multi-indicator framework for mapping cultural ecosystem services: The case of freshwater recreational fishing

    USGS Publications Warehouse

    Villamagna, Amy M.; Mogollon, Beatriz; Angermeier, Paul

    2014-01-01

    Despite recent interest, ecosystem services are not yet fully incorporated into private and public decisions about natural resource management. Cultural ecosystem services (CES) are among the most challenging of services to include because they comprise complex ecological and social properties and processes that make them difficult to measure, map or monetize. Like others, CES are vulnerable to landscape changes and unsustainable use. To date, the sustainability of services has not been adequately addressed and few studies have considered measures of service capacity and demand simultaneously. To facilitate sustainability assessments and management of CES, our study objectives were to (1) develop a spatially explicit framework for mapping the capacity of ecosystems to provide freshwater recreational fishing, an important cultural service, (2) map societal demand for freshwater recreational fishing based on license data and identify areas of potential overuse, and (3) demonstrate how maps of relative capacity and relative demand could be interfaced to estimate sustainability of a CES. We mapped freshwater recreational fishing capacity at the 12-digit hydrologic unit-scale in North Carolina and Virginia using a multi-indicator service framework incorporating biophysical and social landscape metrics and mapped demand based on fishing license data. Mapping of capacity revealed a gradual decrease in capacity eastward from the mountains to the coastal plain and that fishing demand was greatest in urban areas. When comparing standardized relative measures of capacity and demand for freshwater recreational fishing, we found that ranks of capacity exceeded ranks of demand in most hydrologic units, except in 17% of North Carolina and 5% of Virginia. Our GIS-based approach to view freshwater recreational fishing through an ecosystem service lens will enable scientists and managers to examine (1) biophysical and social factors that foster or diminish cultural ecosystem

  15. Biodiversity of trematodes in their intermediate mollusc and fish hosts in the freshwater ecosystems of Europe.

    PubMed

    Faltýnková, Anna; Sures, Bernd; Kostadinova, Aneta

    2016-03-01

    We analysed two novel databases containing 2,380 and 8,202 host-parasite-locality records for trematode parasites of molluscs and fishes, respectively, to assess the biodiversity of trematodes in their intermediate mollusc and fish hosts in the freshwater environment in Europe. The "mollusc" dataset covers large numbers of pulmonate (29 spp.), "prosobranch" (15 spp.) and bivalve (11 spp.) molluscs acting as first intermediate hosts for 171 trematode species of 89 genera and 35 families. Of these, 23 and 40 species utilise freshwater fishes as definitive and second intermediate hosts, respectively. The most frequently recorded families are the Echinostomatidae Looss, 1899, Diplostomidae Poirier, 1886 and Schistosomatidae Stilles & Hassal, 1898, and the most frequently recorded species are Diplostomum spathaceum (Rudolphi, 1819), D. pseudospathaceum Niewiadomska, 1984 and Echinoparyphium recurvatum (von Linstow, 1873). Four snail species harbour extremely rich trematode faunas: Lymnaea stagnalis (L.) (41 spp.); Planorbis planorbis (L.) (39 spp.); Radix peregra (O.F. Müller) (33 spp.); and R. ovata (Draparnaud) (31 spp.). The "fish" dataset covers 99 fish species of 63 genera and 19 families acting as second intermediate hosts for 66 species of 33 genera and nine families. The most frequently recorded families are the Diplostomidae Poirier, 1886, Strigeidae Railliet, 1919 and Bucephalidae Poche, 1907, and the most frequently recorded species are Diplostomum spathaceum (Rudolphi, 1819), Tylodelphys clavata (von Nordmann, 1832) and Posthodiplostomum cuticola (von Nordmann, 1832). Four cyprinid fishes exhibit the highest species richness of larval trematodes: Rutilus rutilus (L.) (41 spp.); Abramis brama (L.) (34 spp.); Blicca bjoerkna (L.) (33 spp.); and Scardinius erythrophthalmus (L.) (33 spp.). Larval stages of 50 species reported in fish are also reported in freshwater molluscs, thus indicating a relatively good knowledge of the life-cycles of fish trematodes in

  16. A novel oxyconforming response in the freshwater fish Galaxias maculatus.

    PubMed

    Urbina, Mauricio A; Glover, Chris N; Forster, Malcolm E

    2012-03-01

    How fish oxygen consumption is modulated by external PO(2) has long been a matter of interest, yet is an experimentally complicated question to answer. In this study closed and semi-closed respirometry were used to evaluate the oxygen consumption rate of the scaleless galaxiid fish, inanga (Galaxias maculatus) as a function of decreasing external PO(2). Both respirometry techniques showed that as environmental oxygen levels declined, oxygen consumption rates also decreased. At no point did inanga regulate oxygen consumption. This is strong evidence that inanga is an oxyconformer. Partitioned respirometry experiments showed that skin plays an important role in oxygen uptake in this fish species, and cutaneous oxygen uptake may have an important role in shaping the oxygen consumption response to hypoxia. PMID:22138470

  17. Parasitic infections in freshwater ornamental fish in Sri Lanka.

    PubMed

    Thilakaratne, I D S I P; Rajapaksha, G; Hewakopara, A; Rajapakse, R P V J; Faizal, A C M

    2003-03-31

    A total of 1520 ornamental fish of 13 species from 26 export farms in Sri Lanka were collected between October 1999 and March 2000 and examined for parasites. Fish species examined were guppy Poecilia reticulata, goldfish Carassius auratus, platy Xiphophorus maculatus, molly Poecilia sphenops, angel Pterophyllum scalare, swordtail Xiphophorus helleri, tetras Hyphessobrycon species, barbs Capeota and Puntius spp., gourami Colisa sp., carp Cyprinus carpio, fighters Betta spelendens and others (Brachydanio and Astronotus spp.). Nine species of monogenean trematodes (Dactylogyrus extensus, Dactylogyrus cf. extensus, D. vastator, Dactylogyrus cf. vastator Dactylogyrus spp., Gyrodactylus turnbulli, G. katherineri, Gyrodactylus cf. katherineri, Gyrodactylus spp.), 7 protozoan species (Trichodina nigra, Trichodina spp., Tetrahymena corlissi, T. pyriformis, Ichthyophthirius multifiliis, Ichthyobodo necator, Piscinoodinium spp.), 3 species of copepod arthropods (Lernaea cyprinacea, Ergasilus ceylonensis, Argulus foliaceus), 1 metacercarial stage of a digenean trematode (Centrocestus spp.) and 1 nematode (Capillaria spp.) were identified. Parasites were found in fish from 23 of the 26 farms with an overall prevalence of parasitism in 45.3% of fish. The variation in farm prevalence among different parasites was significant (p < 0.01). Fish infection rates with monogenean trematodes, protozoans, copepod crustaceans, digenean trematodes and nematodes were 28.3, 18.4, 4.8, 0.8 and 0.4%, respectively. In all, 50 out of 590 (50/590) guppies were infected with Tetrahymena, compared with 13/930 for all other species, which is a statistically significant result (p < 0.01). Similarly, 13/44 and 18/44 carp were infected with Argulus foliaceus and Lernaea cyprinacea, compared with 7/1476 and 15/1476, respectively, for all other species combined (p < 0.01). Capillaria spp. was found only in guppies (4/590) and angel fish (3/92) while Centrocestus spp. was found in goldfish (12/153) only

  18. Parasitic infections in live freshwater tropical fishes imported to Korea.

    PubMed

    Kim, Jeong-Ho; Hayward, Craig James; Joh, Seong-Joon; Heo, Gang-Joon

    2002-11-22

    We examined 15 species of ornamental tropical fishes originating from Southeast Asia to determine the cause of losses among 8 fish farms in Korea. A total of 351 individuals belonging to 5 different families (1 species of Characidae, 6 of Cichlidae, 3 of Cyprinidae, 1 of Heleostomatidae, and 4 of Poecilidae) were collected for the purpose of detecting metazoan and protozoan parasites. Parasites were fixed and stained using routine methods, and identified. We found 3 ciliates, 2 monogeneans, 1 nematode, and 1 copepod from 7 host species. Of these, Ichthyophthirius multifiliis was the most common parasite in our study, and together with Trichodina sp., caused mass mortality of Sumatra barb Puntius tetrazona at 1 farm. We also found Camallanus cotti and Tetrahymena corlissi from guppies Poecilia reticulata, both for the first time in Korea. Farmers consider these 2 pathogens to be the most serious ones in Korea. Gussevia asota from oscar Astronotus ocellatus, and Gyrodactylus bullatarudis from platy Xiphophorus maculatus were also found in Korea for the first time. We believe that appropriate quarantine practices for tropical ornamental fishes should be introduced because the failure to require and implement quarantines has already resulted in the accidental introduction of exotic parasites to fish farms, and because these parasites can cause further economic losses if they become established in the wild. PMID:12542094

  19. LARVAL FISH HABITAT QUALITY : THE EFFECTS OF FRESHWATER FLOW

    EPA Science Inventory

    We sampled larval fish in Suisun Marsh, in the San Francisco Bay estuary from February to June 1994-1999. We used principal components analysis (PCA) and canonical correspondence analysis (CCA) on 13 taxonomic groups making up 99.7% of the catch and several environmental variable...

  20. Hidalgo Fishes: Dataset on freshwater fishes of Hidalgo state (Mexico) in the MZNA fish collection of the University of Navarra (Spain).

    PubMed

    Galicia, David; Pulido-Flores, Griselda; Miranda, Rafael; Monks, Scott; Amezcua-Martínez, Ana; Imas-Lecumberri, María; Chaves-Illana, Angel; Ariño, Arturo H

    2014-01-01

    The state of Hidalgo (Mexico) is an important region from the point of view of biodiversity. However, there exists a significant gap in accessible knowledge about species diversity and distribution, especially regarding to freshwater ecosystems. This dataset comprises the sampling records of two projects developed in Hidalgo between 2007 and 2009 about the freshwater fish communities of Tecocomulco lake and rivers belonging to the Metztitlán Canyon Biosphere Reserve. It contains the taxonomic identity (species level) and basic biometric data (total length and weight) as well as date of collection and coordinates of more than 9000 specimens. This dataset is the primary result of the first and unrepeated exhaustive freshwater fish's survey of Metztitlán Canyon Biosphere Reserve and Tecocomulco lake. It incorporates seven more species to the regional fish fauna, and new exclusive biometric data of ten species. This dataset can be used by studies dealing with, among other interests, North American freshwater fish diversity (species richness, distribution patterns) and biometric analyses, useful for the management and conservation of these areas. The complete dataset is also provided in Darwin Core Archive format. PMID:24843267

  1. Characterizing lentic freshwater fish assemblages using multiple sampling methods

    USGS Publications Warehouse

    Fischer, Jesse R.; Quist, Michael

    2014-01-01

    Characterizing fish assemblages in lentic ecosystems is difficult, and multiple sampling methods are almost always necessary to gain reliable estimates of indices such as species richness. However, most research focused on lentic fish sampling methodology has targeted recreationally important species, and little to no information is available regarding the influence of multiple methods and timing (i.e., temporal variation) on characterizing entire fish assemblages. Therefore, six lakes and impoundments (48–1,557 ha surface area) were sampled seasonally with seven gear types to evaluate the combined influence of sampling methods and timing on the number of species and individuals sampled. Probabilities of detection for species indicated strong selectivities and seasonal trends that provide guidance on optimal seasons to use gears when targeting multiple species. The evaluation of species richness and number of individuals sampled using multiple gear combinations demonstrated that appreciable benefits over relatively few gears (e.g., to four) used in optimal seasons were not present. Specifically, over 90 % of the species encountered with all gear types and season combinations (N = 19) from six lakes and reservoirs were sampled with nighttime boat electrofishing in the fall and benthic trawling, modified-fyke, and mini-fyke netting during the summer. Our results indicated that the characterization of lentic fish assemblages was highly influenced by the selection of sampling gears and seasons, but did not appear to be influenced by waterbody type (i.e., natural lake, impoundment). The standardization of data collected with multiple methods and seasons to account for bias is imperative to monitoring of lentic ecosystems and will provide researchers with increased reliability in their interpretations and decisions made using information on lentic fish assemblages.

  2. A review of the global relationship among freshwater fish, autotrophic activity, and regional climate

    USGS Publications Warehouse

    Deines, Andrew M.; Bunnell, David B.; Rogers, Mark W.; Beard, T. Douglas, Jr.; Taylor, William W.

    2015-01-01

    The relationship between autotrophic activity and freshwater fish populations is an important consideration for ecologists describing trophic structure in aquatic communities, fisheries managers tasked with increasing sustainable fisheries development, and fish farmers seeking to maximize production. Previous studies of the empirical relationships of autotrophic activity and freshwater fish yield have found positive relationships but were limited by small sample sizes, small geographic scopes, and the inability to compare patterns among many types of measurement techniques. Individual studies and reviews have also lacked consistent consideration of regional climate factors which may inform relationships between fisheries and autotrophic activity. We compiled data from over 700 freshwater systems worldwide and used meta-analysis and linear models to develop a comprehensive global synthesis between multiple metrics of autotrophic activity, fisheries, and climate indicators. Our results demonstrate that multiple metrics of fish (i.e., catch per unit effort, yield, and production) increase with autotrophic activity across a variety of fisheries. At the global scale additional variation in this positive relationship can be ascribed to regional climate differences (i.e., temperature and precipitation) across systems. Our results provide a method and proof-of-concept for assessing inland fisheries production at the global scale, where current estimates are highly uncertain, and may therefore inform the continued sustainable use of global inland fishery resources.

  3. Key contributors to variations in fish mercury within and among freshwater reservoirs in Oklahoma, USA.

    PubMed

    Dong, Zhao; Lynch, Robert A; Schaider, Laurel A

    2016-02-01

    Elevated fish mercury (Hg) concentrations in freshwater ecosystems worldwide are a significant human and ecological health concern. Mercury bioaccumulation and biomagnification in lakes and reservoirs are controlled by numerous biogeochemical and ecological factors, contributing to variability in fish Hg concentrations both within and among systems. We measured total mercury concentrations ([THg]) and stable isotopes (δ(15)N, δ(13)C) in over 30 fish species in two connected subtropical freshwater reservoirs (Grand Lake and Lake Hudson, Oklahoma, USA), their tributaries, and local farm ponds, all of which are potentially impacted by nearby atmospheric Hg sources. We also conducted an inter-system analysis among 61 reservoirs in Oklahoma to explore biological, chemical and physical factors associated with fish [THg] across systems. We found that [THg] for most species in Grand Lake and Lake Hudson were relatively low compared to other reservoirs in Oklahoma. There were significant spatial variations in many species within and between Grand Lake and Lake Hudson, even after accounting for length and/or trophic position (based on δ(15)N). Fish in local farm ponds, commonly used in agricultural regions for raising game fish, had 2-17 times higher [THg] than fish of a similar length in nearby reservoirs. The inter-system analysis revealed that pH, water color, rainfall, and nutrients are the best predictors of fish [THg] across systems. Our results provide insight into the key factors associated with fish [THg] variations both within and across systems, and may be useful for exposure assessment and for identifying sites and water bodies prone to high fish [THg] as monitoring priorities. PMID:26729635

  4. Changes of Gel-forming Ability of Surimi from Freshwater fish during Frozen Storage

    NASA Astrophysics Data System (ADS)

    Chang, Jiangzhou; Mori, Satoko; Aoki, Mayumi; Ichikawa, Hisashi; Goto, Shingi; Osatomi, Kiyoshi; Nozaki, Yukinori

    With the view of utilizing a freshwater fish, carp, rainbow trout and silver crucian carp, especially, for fish-paste products, the changes of gel-forming ability of the surimi from these fishes during frozen storage were examined. The gel-forming ability of the surimi with the general cryoprotective additives decreased gradually during frozen storage, but the gel-forming abiIity of surimi with additives in six months after frozen storage was higher than that of additives-free surimi. Each surimi from the three fish species showed resistance to freezing in the order of carp>rainbow trout>silver crucian carp. The gel-forming ability of the surimi from these fishes is low, but the present freshwater fish surimi have the permissible abiIity used for the practical kamaboko making like sardine surimi. On the other hand, a high correlation between gel-forming ability of surimi and total myofibrilIar Ca-ATPase activity, solubiIity and amount of unfrozen water was found.

  5. Assessing Potential Conservation and Restoration Areas of Freshwater Fish Fauna in the Indian River Basins

    NASA Astrophysics Data System (ADS)

    Bhatt, Jay P.; Manish, Kumar; Mehta, Rajender; Pandit, Maharaj K.

    2016-05-01

    Conservation efforts globally are skewed toward terrestrial ecosystems. To date, conservation of aquatic ecosystems, in particular fish fauna, is largely neglected. We provide a country-wide assessment of Indian river ecosystems in order to identify and prioritize areas for protection and restoration of freshwater fish fauna. Using various biodiversity and anthropogenic attributes, coupled with tools of ecological modeling, we delineated areas for fish fauna conservation and restoration in the 20 major river basins of India. To do this, we used prioritization analyses and reserve selection algorithms to derive conservation value index (CVI) and vulnerability index (VI) of the river basins. CVI was estimated using endemicity, rarity, conservation value, and taxonomic singularity, while VI was estimated using a disturbance index derived from percent geographic area of the basin under human settlements, human population density, predominant land use, and total number of exotic fish species in each basin. The two indices, CVI and VI, were converted into geo-referenced maps, and each map was super-imposed onto species richness and forest cover maps, respectively. After superimposition, areas with high CVI and low VI shade intensities were delineated for conservation, while areas with high CVI and high VI shade intensities were demarcated for restoration. In view of the importance of freshwater fish for human livelihoods and consumption, and ecosystems of India's rivers, we call for urgent attention to the conservation of their fish fauna along with restoration of their degraded habitats.

  6. A simple web-based tool to compare freshwater fish data collected using AFS standard methods

    USGS Publications Warehouse

    Bonar, Scott A.; Mercado-Silva, Norman; Rahr, Matt; Torrey, Yuta T.; Cate, Averill, Jr.

    2016-01-01

    The American Fisheries Society (AFS) recently published Standard Methods for Sampling North American Freshwater Fishes. Enlisting the expertise of 284 scientists from 107 organizations throughout Canada, Mexico, and the United States, this text was developed to facilitate comparisons of fish data across regions or time. Here we describe a user-friendly web tool that automates among-sample comparisons in individual fish condition, population length-frequency distributions, and catch per unit effort (CPUE) data collected using AFS standard methods. Currently, the web tool (1) provides instantaneous summaries of almost 4,000 data sets of condition, length frequency, and CPUE of common freshwater fishes collected using standard gears in 43 states and provinces; (2) is easily appended with new standardized field data to update subsequent queries and summaries; (3) compares fish data from a particular water body with continent, ecoregion, and state data summaries; and (4) provides additional information about AFS standard fish sampling including benefits, ongoing validation studies, and opportunities to comment on specific methods. The web tool—programmed in a PHP-based Drupal framework—was supported by several AFS Sections, agencies, and universities and is freely available from the AFS website and fisheriesstandardsampling.org. With widespread use, the online tool could become an important resource for fisheries biologists.

  7. Use of seasonal freshwater wetlands by fishes in a temperate river floodplain

    USGS Publications Warehouse

    Henning, Julie A.; Gresswell, Robert E.; Fleming, Ian A.

    2007-01-01

    This study examined the use of freshwater wetland restoration and enhancement projects (i.e. non-estuarine wetlands subject to seasonal drying) by fish populations. To quantify fish use of freshwater emergent wetlands and assess the effect of wetland enhancement (i.e. addition of water control structures), two enhanced and two unenhanced emergent wetlands were compared, as well as two oxbow habitats within the Chehalis River floodplain. Eighteen fish species were captured using fyke nets and emigrant traps from January to the beginning of June, with the most abundant being three-spined stickleback Gasterosteus aculeatus and Olympic mudminnow Novumbra hubbsi. Coho salmon Oncorhynchus kisutch was the dominant salmonid at all sites. Enhanced wetlands, with their extended hydroperiods, had significantly higher abundances of yearling coho salmon than unenhanced wetlands. Both enhanced and unenhanced emergent wetlands yielded higher abundances of non-game native fishes than oxbow habitats. Oxbow habitats, however, were dominated by coho salmon. Fish survival in the wetland habitats was dependent on emigration to the river before dissolved oxygen concentrations decreased and wetlands became isolated and stranding occurred. This study suggests that wetland enhancement projects with an outlet to the river channel appear to provide fishes with important temporary habitats if they have the opportunity to leave the wetland as dissolved oxygen levels deteriorate.

  8. Trematode Metacercariae in Freshwater Fish from Water Systems of Hantangang and Imjingang in Republic of Korea

    PubMed Central

    Sohn, Woon-Mok; Na, Byoung-Kuk; Cho, Shin-Hyeong; Lee, Soon-Won; Choi, Seung-Bong; Seok, Won-Seok

    2015-01-01

    The infection status of freshwater fish with digenetic trematode metacercariae was examined in water systems of Hantangang and Imjingang (River), the Republic of Korea. A total of 877 (594 from Hantangang and 283 from Imjingang) fishes were examined by the artificial digestion methods. Clonorchis sinensis metacercariae were detected in 7 (1.2%) fishes (in 3 spp.) from Hantangang in Cheorwon-gun, Gangwon-do, and 40 (14.1%) fishes (in 7 spp.) from Munsancheon in Paju-si, Gyeonggi-do. The average densities were 1.9 and 35.6 per fish infected, respectively. Metagonimus spp. metacercariae were detected in 312 (52.5%) and 113 (39.9%) fishes from Hantangang and Imjingang, and their average densities were 47.5 and 9.6 per fish infected, respectively. Centrocestus armatus metacercariae were found in 161 (27.1%) and 70 (24.7%) fishes from Hantangang and Imjingang, and their average number per fish infected was 694 and 82, respectively. Echinostoma spp. metacercariae were detected in 50 (8.4%) and 94 (33.2%) fishes from Hantangang and Imjingang, and their average densities were 9.6 and 23.1 per fish infected, respectively. The infection status of fishes with metacercariae of Stephanoprora spp., Diplostomum spp., Clinostomum complanatum, Metorchis orientalis, and Metorchis taiwanensis were analyzed by surveyed regions. Conclusively, it was confirmed that C. sinensis metacercariae were quite commonly detected in fishes from Munsancheon but rarely from other localities, whereas the metacercariae of other digenetic trematodes were relatively prevalent in fishes from water systems of Hantangang and Imjingang in Korea. PMID:26174822

  9. Ecotoxicology of Hexavalent Chromium in Freshwater Fish: A Critical Review

    PubMed Central

    Velma, Venkatramreddy; Vutukuru, S.S.; Tchounwou, Paul B.

    2010-01-01

    Chromium (Cr) is a naturally occurring element found in rocks, animals, plants, and soil, predominantly in its insoluble trivalent form [Cr(III)]. Intense industrialization and other anthropogenic activities have led to the global occurrence of soluble Cr(VI), which is readily leached from soil to groundwater or surface water, in concentrations above permissible levels. The ecotoxicology of Cr(VI) is linked to its environmental persistence and the ability to induce a variety of adverse effects in biologic systems, including fish. In aquatic ecosystems, Cr(VI) exposure poses a significant threat to aquatic life. This paper reviews the fate and transport of Cr(VI) in the environment and its acute and chronic effects on fish. We also discuss Cr(VI) toxicity at the cellular, biochemical, and genetic levels. An attempt is made in this review to comprehend the staggered data on the toxic effects of Cr(VI) to various species of fish. Such data are extremely useful to the scientific community and public officials involved in health risk assessment and management of environmental contaminants as a guide to the best course of action to restore ecosystems and, in turn, to preserve human health. PMID:19658319

  10. Ecotoxicology of hexavalent chromium in freshwater fish: a critical review.

    PubMed

    Velma, Venkatramreddy; Vutukuru, S S; Tchounwou, Paul B

    2009-01-01

    Chromium (Cr) is a naturally occurring element found in rocks, animals, plants, and soil, predominantly in its insoluble trivalent form [Cr(III)]. Intense industrialization and other anthropogenic activities have led to the global occurrence of soluble hexavalent chromium Cr(VI), which is readily leached from soil to groundwater or surface water, in concentrations above permissible levels. The ecotoxicology of Cr(VI) is linked to its environmental persistence and the ability to induce a variety of adverse effects in biologic systems, including fish. In aquatic ecosystems, Cr(VI) exposure poses a significant threat to aquatic life. This paper reviews the fate and transport of Cr(VI) in the environment and its acute and chronic effects on fish. We also discuss Cr(VI) toxicity at the cellular, biochemical, and genetic levels. An attempt is made in this review to comprehend the staggered data on the toxic effects of Cr(VI) to various species of fish. Such data are extremely useful to the scientific community and public officials involved in health risk assessment and management of environmental contaminants as a guide to the best course of action to restore ecosystems and, in turn, to preserve human health. PMID:19658319

  11. Genotoxicity Effects in Freshwater Fish from a Brazilian Impacted River.

    PubMed

    de Jesus, Isac Silva; Cestari, Marta Margarete; Bezerra, Marcos de Almeida; Affonso, Paulo Roberto Antunes de Mello

    2016-04-01

    This study evaluated the incidence of nuclear abnormalities (NA) in four fish species from an impacted river in Northeastern Brazil, characterized by accumulation of heavy metals and organic sewage. Two carnivores (Serrasalmus brandtii and Hoplias malabaricus) and two omnivore species (Oreochromis niloticus and Geophagus brasiliensis), used as food sources by local populations, were collected during the dry and the rainy season along Contas River basin. Nuclear abnormalities (bulbs, binuclei, lobes, micronuclei, notches, and vacuoles) were reported in all fish samples, with high occurrence in S. brandtii and H. malabaricus, species commonly found in local fish markets. This result agrees with previous analyses of accumulation of trace metals in both species, suggesting an association of genotoxic effects and biomagnification. Moreover, native specimens collected near urban areas presented higher frequencies of NA while O. niloticus seems to be more tolerant to environmental contamination. Therefore, effective policies are required to reduce the contamination of Contas River, since pollution by xenobiotics are potential threats to both local biodiversity and human population. PMID:26894492

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

    USGS Publications Warehouse

    Choudhury, A.; Dick, T.A.

    2000-01-01

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

  13. Effects of chlorine on freshwater fish under various time and chemical conditions: toxicity of chlorine to freshwater fish. Final report

    SciTech Connect

    Brooks, A.S.; Bartos, J.M.; Danos, P.T.

    1982-07-01

    Laboratory bioassays to determine the acute toxicity of monochloramine, dichloramine, hypochlorous acid, and hypochlorite ion to emerald shiners, channel catfish, and rainbow trout were conducted. Four exposure regimes typical of chlorination schedules at operating steam electric power plants were used. Fish were exposed to single 15-minute, 30-minute, 120-minute, and quadruple 30-minute periods. No mortality or LC50 values were determined for each species of fish and chemical species of chlorine. Hypochlorous acid was the most toxic form of chlorine studied, followed closely by dichloramine. Monochloramine and hypochlorite ion were three to four times less toxic than hypochlorous acid and dichloramine. On the average, emerald shiners were 1.8 times more sensitive to chlorine than channel catfish and 3.3 times more sensitive than rainbow trout to the four forms of chlorine. The fish were more tolerant of chlorine during short duration exposures and most sensitive during the continuous 120-minute exposures. The significant differences in toxicity noted among the various chlorine species suggest that careful attention should be paid not only to total residual chlorine but to both the chlorine and fish species present and the duration of exposure expected in establishing chlorination regimes.

  14. Eutrophication as a driver of r-selection traits in a freshwater fish.

    PubMed

    Lin, M; Chevalier, M; Lek, S; Zhang, L; Gozlan, R E; Liu, J; Zhang, T; Ye, S; Li, W; Li, Z

    2014-08-01

    This study tested whether eutrophication could influence life-history traits of a cyprinid, Chanodichthys erythropterus, in 10 Chinese lakes. Using the von Bertalanffy growth model, the asymptotic length (L∞ ) and the growth performance index (IGRO ) were significantly affected by eutrophication. The gonado-somatic index (IG ) and relative fecundity (FR ) were significantly lower in mesotrophic lakes than in eutrophic and hypertrophic lakes. These results indicate that increasing eutrophication affects the life-history tactics of a freshwater fish. PMID:24925695

  15. Hidalgo Fishes: Dataset on freshwater fishes of Hidalgo state (Mexico) in the MZNA fish collection of the University of Navarra (Spain)

    PubMed Central

    Galicia, David; Pulido-Flores, Griselda; Miranda, Rafael; Monks, Scott; Amezcua-Martínez, Ana; Imas-Lecumberri, María; Chaves-Illana, Angel; Ariño, Arturo H.

    2014-01-01

    Abstract The state of Hidalgo (Mexico) is an important region from the point of view of biodiversity. However, there exists a significant gap in accessible knowledge about species diversity and distribution, especially regarding to freshwater ecosystems. This dataset comprises the sampling records of two projects developed in Hidalgo between 2007 and 2009 about the freshwater fish communities of Tecocomulco lake and rivers belonging to the Metztitlán Canyon Biosphere Reserve. It contains the taxonomic identity (species level) and basic biometric data (total length and weight) as well as date of collection and coordinates of more than 9000 specimens. This dataset is the primary result of the first and unrepeated exhaustive freshwater fish’s survey of Metztitlán Canyon Biosphere Reserve and Tecocomulco lake. It incorporates seven more species to the regional fish fauna, and new exclusive biometric data of ten species. This dataset can be used by studies dealing with, among other interests, North American freshwater fish diversity (species richness, distribution patterns) and biometric analyses, useful for the management and conservation of these areas. The complete dataset is also provided in Darwin Core Archive format. PMID:24843267

  16. First isolation of hirame rhabdovirus from freshwater fish in Europe.

    PubMed

    Borzym, E; Matras, M; Maj-Paluch, J; Baud, M; De Boisséson, C; Talbi, C; Olesen, N J; Bigarré, L

    2014-05-01

    A rhabdovirus was isolated in cell culture inoculated with tissue material from diseased grayling, Thymallus thymallus (L.), originating from a fish farm affected by a mortality episode in Poland. Diagnostics tests showed that the virus was not related to novirhabdoviruses known in Europe, nor to vesiculovirus-like species, except perch rhabdovirus (PRhV) with which it shared moderate serological relations. However, RT-PCR with PRhV probes gave negative results. To identify the virus, a random-priming sequence-independent single primer amplification was adopted. Surprisingly, two of the obtained sequences exhibited a high identity (>99%) with hirame rhabdovirus (HIRRV), a novirhabdovirus usually found in fish in marine Asiatic countries, for instance Japan, China and Korea. The full-length sequence of the phosphoprotein gene (P) demonstrated a higher identity of the present isolate with HIRRV from China compared with the Korean isolate. An identical viral sequence was also found in brown trout, Salmo trutta trutta L., affected by mortalities in a second farm in the same region, after a likely contamination from the grayling farm. To our knowledge, this is the first report of HIRRV in Europe, and in two hosts from fresh water that have not been described before as susceptible species. PMID:23962315

  17. A New Freshwater Biodiversity Indicator Based on Fish Community Assemblages

    PubMed Central

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

    2013-01-01

    Biodiversity has reached a critical state. In this context, stakeholders need indicators that both provide a synthetic view of the state of biodiversity and can be used as communication tools. Using river fishes as model, we developed community indicators that aim at integrating various components of biodiversity including interactions between species and ultimately the processes influencing ecosystem functions. We developed indices at the species level based on (i) the concept of specialization directly linked to the niche theory and (ii) the concept of originality measuring the overall degree of differences between a species and all other species in the same clade. Five major types of originality indices, based on phylogeny, habitat-linked and diet-linked morphology, life history traits, and ecological niche were analyzed. In a second step, we tested the relationship between all biodiversity indices and land use as a proxy of human pressures. Fish communities showed no significant temporal trend for most of these indices, but both originality indices based on diet- and habitat- linked morphology showed a significant increase through time. From a spatial point of view, all indices clearly singled out Corsica Island as having higher average originality and specialization. Finally, we observed that the originality index based on niche traits might be used as an informative biodiversity indicator because we showed it is sensitive to different land use classes along a landscape artificialization gradient. Moreover, its response remained unchanged over two other land use classifications at the global scale and also at the regional scale. PMID:24278356

  18. Identifying correlates of success and failure of native freshwater fish reintroductions.

    PubMed

    Cochran-Biederman, Jennifer L; Wyman, Katherine E; French, William E; Loppnow, Grace L

    2015-02-01

    Reintroduction of imperiled native freshwater fish is becoming an increasingly important conservation tool amidst persistent anthropogenic pressures and new threats related to climate change. We summarized trends in native fish reintroductions in the current literature, identified predictors of reintroduction outcome, and devised recommendations for managers attempting future native fish reintroductions. We constructed random forest classifications using data from 260 published case studies of native fish reintroductions to estimate the effectiveness of variables in predicting reintroduction outcome. The outcome of each case was assigned as a success or failure on the basis of the author's perception of the outcome and on whether or not survival, spawning, or recruitment were documented during post-reintroduction monitoring. Inadequately addressing the initial cause of decline was the best predictor of reintroduction failure. Variables associated with habitat (e.g., water quality, prey availability) were also good predictors of reintroduction outcomes, followed by variables associated with stocking (e.g., genetic diversity of stock source, duration of stocking event). Consideration of these variables by managers during the planning process may increase the likelihood for successful outcomes in future reintroduction attempts of native freshwater fish. PMID:25115187

  19. Risk assessment of residual DDTs in freshwater and marine fish cultivated around the Pearl River Delta, China.

    PubMed

    Leung, S Y; Kwok, C K; Nie, X P; Cheung, K C; Wong, M H

    2010-02-01

    Six species of freshwater fish collected from 10 fishponds in Shunde and Zhongshan, China, four species of marine fishes collected from different mariculture farms [four in Hong Kong (Tung Lung Chau, Ma Wan, Cheung Chau and Kat O) and two in mainland China (Daya Bay and Shenzhen)] together with feed (both trash fish and commercial pellets) and sediment were analyzed for DDTs. Total DDTs in freshwater fish flesh decreased in the order of: carnivores [1742 microg/kg lipid weight (l.w.)] > herbivores (165 microg/kg, l.w.) > omnivores (42.5 microg/kg, l.w.), with the highest concentration detected in mandarin fish (Siniperca chuatsi) (2641 microg/kg, l.w.). For marine fish, snubnose pompano (Trachinotus blochii) and orange-spotted grouper (Epinephelus coioides) collected in Ma Wan contained elevated levels of total DDTs (2590 and 2034 microg/kg l.w., respectively). Trash fish used in both freshwater and marine fish farms contained significantly higher levels (86.5-641 microg/kg l.w.) (p < 0.05) of DDTs than in commercial pellets, but correlations between DDT levels in fish feed and muscle were not significant. The elevated biota-sediment accumulating factor for tilapia (Tilapia mossambicus) (24.1) indicated that accumulation of DDTs from sediment to the fish was evident. It can be concluded that trash fish should not be used for fish culture in order to lower the level of residual DDTs in fish muscle. PMID:19603131

  20. Chemical analysis of endolymph and the growing otolith: fractionation of metals in freshwater fish species.

    PubMed

    Melancon, Sonia; Fryer, Brian J; Markham, James L

    2009-06-01

    The fractionation of metals from water to otolith is an area of research that has received relatively limited attention, especially in freshwater systems. The objectives of the present research were to study the metal partitioning between otolith and endolymph of two freshwater species: Lake trout (Salvelinus namaycush), and burbot (Lota lota). We also included the chemical analyses of water and blood from fish of the same species collected in the same area but during different years. These results provide insight regarding the partition of metals between water and fish. This is one of the first studies to provide a range of trace metal concentrations for endolymph and the growing otolith (both aragonite and vaterite) and to directly measure otolith-endolymph partition coefficients for freshwater fish. The trace elements (Mg, Sr, and Ba) most often used as otolith elemental tracers were the ones with the lowest uptake from water to blood. We found that endolymph and whole blood had similar metal concentrations, with Mg and Fe being the only elements enriched in whole blood. Results showed few significant differences in trace metal content between wild lake trout and burbot endolymph (except for K, Mg, and Ba), but significant differences existed between their aragonitic otoliths. These results suggest two different crystallization processes in these species or the presence of different proteins (and/or organic matrices) that would selectively influence elemental incorporation in the otoliths. PMID:19154085

  1. Molecular Zoogeography of Freshwater Fishes in the Southeastern United States

    PubMed Central

    Bermingham, Eldredge; Avise, John C.

    1986-01-01

    Restriction fragment length polymorphisms in mitochondrial DNA (mtDNA) were used to reconstruct evolutionary relationships of conspecific populations in four species of freshwater fish—Amia calva, Lepomis punctatus, L. gulosus, and L. microlophus. A suite of 14-17 endonucleases was employed to assay mtDNAs from 305 specimens collected from 14 river drainages extending from South Carolina to Louisiana. Extensive mtDNA polymorphism was observed within each assayed species. In both phenograms and Wagner parsimony networks, mtDNA clones that were closely related genetically were usually geographically contiguous. Within each species, major mtDNA phylogenetic breaks also distinguished populations from separate geographic regions, demonstrating that dispersal and gene flow have not been sufficient to override geographic influences on population subdivision.—Importantly, there were strong patterns of congruence across species in the geographic placements of the mtDNA phylogenetic breaks. Three major boundary regions were characterized by concentrations of phylogenetic discontinuities, and these zones agree well with previously described zoogeographic boundaries identified by a different kind of data base—distributional limits of species—suggesting that a common set of historical factors may account for both phenomena. Repeated episodes of eustatic sea level change along a relatively static continental morphology are the likely causes of several patterns of drainage isolation and coalescence, and these are discussed in relation to the genetic data.—Overall, results exemplify the positive role that intraspecific genetic analyses may play in historical zoogeographic reconstruction. They also point out the potential inadequacies of any interpretations of population genetic structure that fail to consider the influences of history in shaping that structure. PMID:17246340

  2. Costs influence male mate choice in a freshwater fish.

    PubMed

    Wong, Bob B M; Jennions, Michael D

    2003-08-01

    It is well known that female mate choice decisions depend on the direct costs of choosing (either because of search costs or male-imposed costs). Far less is known about how direct fitness costs affect male mate choice. We conducted an experiment to investigate male mate choice in a fish, the Pacific blue-eye (Pseudomugil signifer). Preferred females were larger, probably because larger females are also more fecund. Males, however, were consistent in their choice of female only when the costs of associating with prospective mates were equal. By contrast, males were far less consistent in their choice when made to swim against a current to remain with their initially preferred mate. Our results suggest that males may also respond adaptively to changes in the costs of choosing. PMID:12952630

  3. Reproductive biology of freshwater fishes from the Venezuelan floodplains.

    PubMed

    Guerrero, H Y; Cardillo, E; Poleo, G; Marcano, D

    2009-03-01

    This review describes the endocrine changes that occur during the annual reproductive cycle of Pygocentrus cariba, Pimelodus blochii, and Oxydoras sifontesi and their relationships with the environmental characteristics of Venezuelan floodplains. Most reproductive studies of teleosts have focused on changes that occur during annual cycles in temperate species but, in tropical fish, this has been examined less frequently. P. cariba, P. blochii, and O. sifontesi are seasonal breeders widely distributed along the Orinoco River. Under natural conditions they have an annual gonadal cycle closely related to changes in the annual hydrology cycle of the Orinoco River which defines two seasons on the floodplain: inundation and isolation. The reproductive cycle of these species seems to be controlled by cues from the external environment. Relevant data about gonadal maturation, for example gonadosomatic index and sexual hormones secretion, are contrasted. The role of catecholamines in neuroendocrine control of the reproductive axis is also considered in this work. PMID:18726246

  4. Species-specific preferences of German recreational anglers for freshwater fishing experiences, with emphasis on the intrinsic utilities of fish stocking and wild fishes.

    PubMed

    Arlinghaus, R; Beardmore, B; Riepe, C; Meyerhoff, J; Pagel, T

    2014-12-01

    To answer the question, whether anglers have an intrinsic preference for stocking or a preference for catch outcomes (e.g. catch rates) believed to be maintained by stocking, a discrete choice experiment was conducted among a sample of anglers (n = 1335) in Lower Saxony, Germany. After controlling for catch aspects of the fishing experience, no significant influence of two stocking attributes (stocking frequency and composition of the catch in terms of wild v. hatchery fishes) on the utility gained from fishing was found for any of the freshwater species that were studied. It was concluded that the previously documented large appreciation of fish stocking by anglers may be indicative of an underlying preference for sufficiently high catches rather than reflect an intrinsic preference for stocking or the catching of wild fishes per se. PMID:25469949

  5. Characterization of fish assemblages and population structure of freshwater fish in two Tunisian reservoirs: implications for fishery management.

    PubMed

    Mili, Sami; Ennouri, Rym; Dhib, Amel; Laouar, Houcine; Missaoui, Hechmi; Aleya, Lotfi

    2016-06-01

    To monitor and assess the state of Tunisian freshwater fisheries, two surveys were undertaken at Ghezala and Lahjar reservoirs. Samples were taken in April and May 2013, a period when the fish catchability is high. The selected reservoirs have different surface areas and bathymetries. Using multi-mesh gill nets (EN 14575 amended) designed for sampling fish in lakes, standard fishing methods were applied to estimate species composition, abundance, biomass, and size distribution. Four species were caught in the two reservoirs: barbel, mullet, pike-perch, and roach. Fish abundance showed significant change according to sampling sites, depth strata, and the different mesh sizes used. From the reservoir to the tributary, it was concluded that fish biomass distribution was governed by depth and was most abundant in the upper water layers. Species size distribution differed significantly between the two reservoirs, exceeding the length at first maturity. Species composition and abundance were greater in Lahjar reservoir than in Ghezala. Both reservoirs require support actions to improve fish productivity. PMID:27220503

  6. Chemicals of predatory mosquitofish (Gambusia affinis) influence selection of oviposition site by Culex mosquitoes.

    PubMed

    Angelon, Kim A; Petranka, James W

    2002-04-01

    Ovipositing insects may avoid aquatic sites where there is high predation risk to their offspring, but the proximate mechanisms that mediate avoidance behavior are poorly resolved. We conducted an experiment to determine whether mosquitoes would reduce oviposition rates in pools containing chemicals of the mosquitofish (Gambusia affinis), a voracious predator that is widely employed to control mosquitoes. Experimental treatments consisted of outdoor pools that contained known concentrations of fish chemicals (low, medium, or high) or no fish chemicals (control). The pools were arranged in a randomized block design, and the number of mosquito larvae in each pool served as the response variable to estimate relative oviposition rate. Members of the Culex pipiens complex were the main colonizers of the pools. The mean number of larvae per pool differed among treatments (P = 0.026) and was about three times greater in control pools compared with those receiving medium and high concentrations of fish chemicals. Pairwise comparisons indicate that only medium and high treatments differed significantly from controls, suggesting that a threshold concentration exists below which mosquitoes cannot reliably detect predators. Our data suggest that the effectiveness of Gambusia affinis in controlling mosquitoes may be compromised if adult mosquitoes respond to fish stocking by shifting to nearby breeding sites that lack fish. We discuss issues conceming the use of Gambusia in biological control programs within the context of these new findings. PMID:12035927

  7. Do freshwater fishes diversify faster than marine fishes? A test using state-dependent diversification analyses and molecular phylogenetics of new world silversides (atherinopsidae).

    PubMed

    Bloom, Devin D; Weir, Jason T; Piller, Kyle R; Lovejoy, Nathan R

    2013-07-01

    Freshwater habitats make up only ∼0.01% of available aquatic habitat and yet harbor 40% of all fish species, whereas marine habitats comprise >99% of available aquatic habitat and have only 60% of fish species. One possible explanation for this pattern is that diversification rates are higher in freshwater habitats than in marine habitats. We investigated diversification in marine and freshwater lineages in the New World silverside fish clade Menidiinae (Teleostei, Atherinopsidae). Using a time-calibrated phylogeny and a state-dependent speciation-extinction framework, we determined the frequency and timing of habitat transitions in Menidiinae and tested for differences in diversification parameters between marine and freshwater lineages. We found that Menidiinae is an ancestrally marine lineage that independently colonized freshwater habitats four times followed by three reversals to the marine environment. Our state-dependent diversification analyses showed that freshwater lineages have higher speciation and extinction rates than marine lineages. Net diversification rates were higher (but not significant) in freshwater than marine environments. The marine lineage-through time (LTT) plot shows constant accumulation, suggesting that ecological limits to clade growth have not slowed diversification in marine lineages. Freshwater lineages exhibited an upturn near the recent in their LTT plot, which is consistent with our estimates of high background extinction rates. All sequence data are currently being archived on Genbank and phylogenetic trees archived on Treebase. PMID:23815658

  8. The influence of external subsidies on diet, growth and Hg concentrations of freshwater sport fish: implications for management and fish consumption advisories.

    PubMed

    Lepak, Jesse M; Hooten, Mevin B; Johnson, Brett M

    2012-10-01

    Mercury (Hg) contamination in sport fish is a global problem. In freshwater systems, food web structure, sport fish sex, size, diet and growth rates influence Hg bioaccumulation. Fish stocking is a common management practice worldwide that can introduce external energy and contaminants into freshwater systems. Thus, stocking can alter many of the factors that influence Hg concentrations in sport fish. Here we evaluated the influence of external subsidies, in the form of hatchery-raised rainbow trout Oncorhynchus mykiss on walleye Sander vitreus diet, growth and Hg concentrations in two freshwater systems. Stocking differentially influenced male and female walleye diets and growth, producing a counterintuitive size-contamination relationship. Modeling indicated that walleye growth rate and diet were important explanatory variables when predicting Hg concentrations. Thus, hatchery contributions to freshwater systems in the form of energy and contaminants can influence diet, growth and Hg concentrations in sport fish. Given the extensive scale of fish stocking, and the known health risks associated with Hg contamination, this represents a significant issue for managers monitoring and manipulating freshwater food web structures, and policy makers attempting to develop fish consumption advisories to protect human health in stocked systems. PMID:22699411

  9. The influence of external subsidies on diet, growth and Hg concentrations of freshwater sport fish: implications for management and fish consumption advisories

    USGS Publications Warehouse

    Lepak, J.M.; Hooten, M.B.; Johnson, B.M.

    2012-01-01

    Mercury (Hg) contamination in sport fish is a global problem. In freshwater systems, food web structure, sport fish sex, size, diet and growth rates influence Hg bioaccumulation. Fish stocking is a common management practice worldwide that can introduce external energy and contaminants into freshwater systems. Thus, stocking can alter many of the factors that influence Hg concentrations in sport fish. Here we evaluated the influence of external subsidies, in the form of hatchery-raised rainbow trout Oncorhynchus mykiss on walleye Sander vitreus diet, growth and Hg concentrations in two freshwater systems. Stocking differentially influenced male and female walleye diets and growth, producing a counterintuitive size-contamination relationship. Modeling indicated that walleye growth rate and diet were important explanatory variables when predicting Hg concentrations. Thus, hatchery contributions to freshwater systems in the form of energy and contaminants can influence diet, growth and Hg concentrations in sport fish. Given the extensive scale of fish stocking, and the known health risks associated with Hg contamination, this represents a significant issue for managers monitoring and manipulating freshwater food web structures, and policy makers attempting to develop fish consumption advisories to protect human health in stocked systems.

  10. Accumulation of heavy metals in freshwater fish in cage aquaculture at Cirata Reservoir, West Java, Indonesia.

    PubMed

    Salami, Indah Rachmatiah Siti; Rahmawati, Suphia; Sutarto, Ratri Indri Hapsari; Jaya, Pinilih Marendra

    2008-10-01

    Freshwater fish demand in West Java is supported by cage aquaculture in reservoirs. Cirata Reservoir is one of three cascading hydropower reservoirs built along the Citarum River that receives domestic and industrial wastes. Water pollution by heavy metals, such as copper and lead, increases the health risk of humans who consume the fish. The study was aimed to evaluate the concentration of copper and lead in fish, specifically on Cyprinus carpio, that are widely cultivated in the Cirata Reservoir. Two sizes of fish were collected from five sampling points around floating-cage area. The liver of the fish was found to contain the highest copper level, followed by gills, skin, and muscle. In contrast, lead was also high in the liver, followed by skin, gills, and the muscle, but the copper concentration found in the tissues studied was much higher (31.111 +/- 17.911 mg/kg dry wt) than the lead content (0.290 +/- 0.346 mg/kg dry wt). The concentration of metals in smaller fish was always higher than than that in bigger fish. The metals content was also compared to those in fish exposed in a semistatic laboratory-scale study using Oreochromis niloticus. After 28 days exposure with 0.01 mg Cu/L, fish accumulated 21.53 mg Cu/kg dry wt, whereas for Pb exposure of 0.016 mg/L, fish accumulated up to 7 mg/kg dry wt. However, estimates of Cu and Pb intake from C. carpio consumption were still below the average daily intake (ADI) limit. This study suggested that monitoring of water quality and heavy metals in cultured fish is important in protecting human health. PMID:18991927

  11. Discrimination between several diterpenoid compounds in feeding by Gambusia affinis.

    PubMed

    Aceret, T L; Sammarco, P W; Coll, J C; Uchio, Y

    2001-01-01

    The alcyonacean soft coral Sinularia flexibilis Quoy and Gaimard produces a number of bioactive complementary (secondary) metabolites. The ability of three of these diterpenes - flexibilide, sinulariolide and dihydroflexibilide - to elicit differential discriminatory feeding behavior in Gambusia affinis was assessed in a feeding deterrence study. Terpene-impregnated fish flakes were offered to fish trained to feed on such food, and their responses (acceptance, rejection, avoidance, or no response) were assessed as indicative of feeding deterrence. Food treated with sinulariolide (a compound previously determined to be non-bioactive) was generally accepted at a 1% concentration. It was avoided and rejected, however, at a concentration of 10%, a concentration level generally restricted to polyp-rich branchlets. This indicated negative olfactory and palatability cues, respectively. Flexibilide-treated flakes were accepted to some extent by the fish at the 1% concentration, but strongly avoided at the 10% concentration, indicating effective feeding deterrence via olfaction. Dihydroflexibilide-impregnated flakes were strongly rejected even at low concentrations (1%) after tasting, indicating a negative palatibility cue. They were strongly avoided or rejected at higher concentrations (10%), indicating a negative olfactory cue as well. This response at higher concentrations indicates that sinulariolide and flexibilide become effective at concentrations between 1% and 10%. Such concentrations may be found in the polypary (polyp-bearing portion) of the soft coral colonies. Dihydroflexibilide elicited the strongest negative palatability response from these test fish. The feeding deterrence characteristics of the compounds determined here represent the potentials of individual compounds to elicit differential feeding responses in organisms like Gambusia which are capable of discriminating between different but closely related complementary (secondary) metabolites. PMID

  12. A longitudinal study of mercury exposure associated with consumption of freshwater fish from a reservoir in rural south central USA.

    PubMed

    Dong, Zhao; Jim, Rebecca C; Hatley, Earl L; Backus, Ann S N; Shine, James P; Spengler, John D; Schaider, Laurel A

    2015-01-01

    Methylmercury (MeHg) exposure through fish consumption is a worldwide health concern. Saltwater fish account for most dietary MeHg exposure in the general U.S. population, but less is known about seasonal variations in MeHg exposure and fish consumption among millions of freshwater anglers. This longitudinal study examined associations between MeHg exposure and fish consumption in a rural, low-income population relying on a freshwater reservoir (Oklahoma, USA) for recreational and subsistence fishing. We interviewed 151 participants, primarily anglers and their families, seasonally for one year using 90-day recall food frequency questionnaires to assess general and species-specific fish consumption, and tested hair biomarker samples for total mercury (THg hair). Mean THg hair was 0.27 μg/g (n=595, range: 0.0044-3.1 μg/g), with 4% of participants above U.S. EPA's guideline for women of childbearing age and children. Mean fish consumption was 58 g/d (95% CI: 49-67 g/d), within the range previously reported for recreational freshwater anglers and above the national average. Unlike the general U.S. population, freshwater species contributed the majority of fish consumption (69%) and dietary Hg exposure (60%) among participants, despite relatively low THg in local fish. THg hair increased with fish consumption, age, and education, and was higher among male participants and the lowest in winter. Our results suggest that future studies of anglers should consider seasonality in fish consumption and MeHg exposure and include household members who share their catch. Efforts to evaluate benefits of reducing Hg emissions should consider dietary patterns among consumers of fish from local freshwater bodies. PMID:25460632

  13. A Longitudinal Study of Mercury Exposure Associated with Consumption of Freshwater Fish from a Reservoir in Rural South Central USA

    PubMed Central

    Dong, Zhao; Jim, Rebecca C.; Hatley, Earl L.; Backus, Ann S. N.; Shine, James P.; Spengler, John D.; Schaider, Laurel A.

    2015-01-01

    Methylmercury (MeHg) exposure through fish consumption is a worldwide health concern. Saltwater fish account for most dietary MeHg exposure in the general U.S. population, but less is known about seasonal variations in MeHg exposure and fish consumption among millions of freshwater anglers. This longitudinal study examined associations between MeHg exposure and fish consumption in a rural, low-income population relying on a freshwater reservoir (Oklahoma, USA) for recreational and subsistence fishing. We interviewed 151 participants, primarily anglers and their families, seasonally for one year using 90-day recall food frequency questionnaires to assess general and species-specific fish consumption, and tested hair biomarker samples for total mercury (THghair). Mean THghair was 0.27 μg/g (n=595, range: 0.0044–3.1 μg/g), with 4% of participants above U.S. EPA's guideline for women of childbearing age and children. Mean fish consumption was 58 g/d (95% CI: 49–67 g/d), within the range previously reported for recreational freshwater anglers and above the national average. Unlike the general U.S. population, freshwater species contributed the majority of fish consumption (69%) and dietary Hg exposure (60%) among participants, despite relatively low THg in local fish. THghair increased with fish consumption, age, and education, and was higher among male participants and lowest in winter. Our results suggest that future studies of anglers should consider seasonality in fish consumption and MeHg exposure and include household members who share their catch. Efforts to evaluate benefits of reducing Hg emissions should consider dietary patterns among consumers of fish from local freshwater bodies. PMID:25460632

  14. Isolation and characterisation of flavobacteria from wild and cultured freshwater fish species in Hungary.

    PubMed

    Varga, Zsuzsanna; Sellyei, Boglárka; Paulus, Petra; Papp, Melitta; Molnár, Kálmán; Székely, Csaba

    2016-03-01

    The objective of this study was to survey the incidence of Flavobacterium columnare in wild and cultured freshwater fish species in Hungary. This bacterium usually causes disease in waters of more than 25 °C temperature. However, with the introduction of intensive fish farming systems, infected fish exposed to stress develop disease signs also at lower temperatures; in addition, the temperature of natural waters rises to the critical level due to global warming. Twenty-five isolates from wild and cultured freshwater fishes were identified as F. columnare by specific PCR, although both the fragment lengths and the results of PCRRFLP genotyping with BsuRI (HaeIII) and RsaI restriction enzymes raised doubts regarding this species classification. Sequencing of the 16S ribosomal RNA gene revealed that 23 isolates belonged to the species F. johnsoniae and two represented Chryseobacterium spp. The isolates were found to have high-level multidrug resistance: all were resistant to ampicillin and polymyxin B, the 23 F. johnsoniae strains to cotrimoxazole, 88% of them to gentamicin, and 72% to chloramphenicol. The majority of the 25 isolates were sensitive to erythromycin (88%), furazolidone (76%), and florfenicol (68%). PMID:26919138

  15. Planning for Production of Freshwater Fish Fry in a Variable Climate in Northern Thailand

    NASA Astrophysics Data System (ADS)

    Uppanunchai, Anuwat; Apirumanekul, Chusit; Lebel, Louis

    2015-10-01

    Provision of adequate numbers of quality fish fry is often a key constraint on aquaculture development. The management of climate-related risks in hatchery and nursery management operations has not received much attention, but is likely to be a key element of successful adaptation to climate change in the aquaculture sector. This study explored the sensitivities and vulnerability of freshwater fish fry production in 15 government hatcheries across Northern Thailand to climate variability and evaluated the robustness of the proposed adaptation measures. This study found that hatcheries have to consider several factors when planning production, including: taking into account farmer demand; production capacity of the hatchery; availability of water resources; local climate and other area factors; and, individual species requirements. Nile tilapia is the most commonly cultured species of freshwater fish. Most fry production is done in the wet season, as cold spells and drought conditions disrupt hatchery production and reduce fish farm demand in the dry season. In the wet season, some hatcheries are impacted by floods. Using a set of scenarios to capture major uncertainties and variability in climate, this study suggests a couple of strategies that should help make hatchery operations more climate change resilient, in particular: improving hatchery operations and management to deal better with risks under current climate variability; improving monitoring and information systems so that emerging climate-related risks are known sooner and understood better; and, research and development on alternative species, breeding programs, improving water management and other features of hatchery operations.

  16. Environmental indicators of habitat quality in a migratory freshwater fish fauna

    SciTech Connect

    McDowall, R.M.; Taylor, M.J.

    2000-04-01

    In general, diadromous (and particularly amphidromous and catadromous) freshwater fishes decline in frequency of occurrence, change age/size structure, and probability also decline in abundance with increasing elevation and distance upstream from the sea. In freshwater fish faunas with a high proportion of migratory species, as in New Zealand, these changes in occurrence and abundance result in a breakdown of the relationship between fish abundance and habitat quality, making application of the index of biotic integrity (IBI) as a measure of habitat quality problematical since the index depends on the relationship between population metrics and habitat quality. An alternative approach applicable to assessing temporal changes in habitat quality and that uses a large database on fish distributions, involves analysis of the distribution of species across their natural distributions. In this paper, the authors generate curves of occurrence of species across ranges of altitude and distance inland and show, through comparisons of data subsets, that the curves are consistent estimators of species' occurrence and therefore useful as indicators of habitat quality.

  17. Planning for Production of Freshwater Fish Fry in a Variable Climate in Northern Thailand.

    PubMed

    Uppanunchai, Anuwat; Apirumanekul, Chusit; Lebel, Louis

    2015-10-01

    Provision of adequate numbers of quality fish fry is often a key constraint on aquaculture development. The management of climate-related risks in hatchery and nursery management operations has not received much attention, but is likely to be a key element of successful adaptation to climate change in the aquaculture sector. This study explored the sensitivities and vulnerability of freshwater fish fry production in 15 government hatcheries across Northern Thailand to climate variability and evaluated the robustness of the proposed adaptation measures. This study found that hatcheries have to consider several factors when planning production, including: taking into account farmer demand; production capacity of the hatchery; availability of water resources; local climate and other area factors; and, individual species requirements. Nile tilapia is the most commonly cultured species of freshwater fish. Most fry production is done in the wet season, as cold spells and drought conditions disrupt hatchery production and reduce fish farm demand in the dry season. In the wet season, some hatcheries are impacted by floods. Using a set of scenarios to capture major uncertainties and variability in climate, this study suggests a couple of strategies that should help make hatchery operations more climate change resilient, in particular: improving hatchery operations and management to deal better with risks under current climate variability; improving monitoring and information systems so that emerging climate-related risks are known sooner and understood better; and, research and development on alternative species, breeding programs, improving water management and other features of hatchery operations. PMID:26105968

  18. Literature review of the concentration ratios of selected radionuclides in freshwater and marine fish

    SciTech Connect

    Poston, T.M.; Klopfer, D.C.

    1986-09-01

    Concentration ratios (CR's) used for modeling the uptake and food chain transport of radionuclides in fish have usually been conservative; that is, at the high end of reported values. This practice ensures that the dose to the consumer of contaminated fish will not be underestimated. In many models, however, conservative values have been used for all variables that have any uncertainty associated with them. As a result the dose to the consumer is overestimated. Realistic CR values need to be developed to establish model parameters that will accurately reflect tissue burdens in fish and resulting dose rates to consumers. This report reviews and summarizes published literature on the uptake and distribution of stable and radioactive isotopes of 26 elements. Based on this review, we have made recommendations on CR values to be used for modeling the accumulation of radionuclides in fish. Our recommendations are compared with CR values reported in other publications. A generic discussion of abiotic and biotic factors that influence CR values is provided so that CR values may be adjusted based on site-specific characteristics of the fishes habitat. Recommended CR values for freshwater fish and for marine fish are listed. Although this report emphasizes radionuclides, it is applicable to stable elements as well.

  19. New trends in parasitic infections of cultured freshwater fish.

    PubMed

    Odening, K

    1989-07-01

    The 1980s are characterized by the appearance of new fish parasitoses, the clarification of the aetiology of diseases and new insights into the process of infection and the development of important parasites, especially myxosporidians. Two phaerosporoses have entered into the foreground: swimbladder inflammation (SBI) caused by Sphaerospora renicola in common carp and proliferative kidney disease (PKD) in salmonids. Both diseases must be reported in the German Democratic Republic (GDR). The connection between the "C-protozoa" in the blood and S. renicola in SBI was recently clarified by experiments by Molnar (1988). The results of our own investigations indicate that the "K-protozoa" phase of S. renicola parasitizes mainly the brain and sometimes the spleen, pancreas and liver before appearing in the swimbladder. Hedrick et al. (1988) in the USA and Odening et al. (1988b) in Europe first reported a Sphaerospora sp. in Salmo gairdneri in connection with PKD. The spectacular findings by Wolf and Markiw (1984) and El-Matbouli (1988) elucidating on the life cycle of Myxobolus cerebralis have not yet brought the revolutionary change expected for a general new estimation of myxosporidian transmission as a basis for ecotechnological control measures. Examples for the formation of new regionally specific parasite colonizations offer the far Eastern cyprinids introduced into Europe. In the GDR the silver carp is infected by Chloromyxum barbi (Myxosporidia) (Sedlazsek), the pathogenic Gyrodactylus sprostonae and two new Gyrodactylus species (Pectobathrii) (Lux). Eel parasites new to Europe are the obviously imported and highly pathogenic nematodes Anguillicola crassus and A. novaezelandiae (Paggi et al., 1982; Moravec and Taraschewski, 1988). In Central Europe the infestation of rainbow trout by the tapeworm Proteocephalus neglectus is increasing (Priemer, 1980; Hanzelova et al., 1988). PMID:2669320

  20. Influence of protective agents in the toxicity of cadmium to a freshwater fish (Channa punctatus)

    SciTech Connect

    Sastry, K.V.; Shukla, V. )

    1994-11-01

    Toxicity of cadmium to fishes has stimulated considerable interest in recent years. Studies have shown that other metals, vitamins, chelating agents and protein diets which alter the physiological, biochemical and behavioral aspects in fish also influence cadmium toxicity. Selenium, as a micronutrient, and zinc, as an essential metal, have been well known for many years for their role in animal physiology. Respiratory parameters of an animal are important for assessing the toxic stress, as they are valuable indicators of the functions of all vital life-sustaining processes. In the present study, the effects of cadmium on the rate of uptake of oxygen by the whole body and different tissues of the freshwater fish Channa punctatus were investigated. The influence of zinc, selenium and ascorbic acid on the toxicity of cadmium were also examined. 14 refs., 6 tabs.

  1. A NATIONAL COMPENDIUM OF FRESHWATER FISH AND WATER TEMPERATURE DATA. VOLUME I: DATA MANAGEMENT TECHNIQUES, OUTPUT EXAMPLES AND LIMITATIONS

    EPA Science Inventory

    The present study resulted in the compilation of a computer data base containing historical fish distribution data with accompanying water temperature data from about 1930-1972 for over 300 species of freshwater fish from 574 locations in the United States and provides the first ...

  2. Assessment of freshwater fish assemblages and their habitats in the National Park Service system of the southeastern United States

    USGS Publications Warehouse

    Long, James M.; Nibbelink, Nathan P.; McAbee, Kevin T.; Stahli, Julie W.

    2012-01-01

    The southeast region of the United States contains the highest diversity of freshwater fish species in the country: approximately 662 species. Existing protected areas like units of the National Park Service (NPS) should reflect this biodiversity, but there has been no broad-scale assessment. We compiled several data sets identifying native freshwater fish species distributions in and surrounding NPS units and threats to those resources. Focusing on the 26 NPS units containing only freshwater fish species, we documented 288 species within NPS boundaries. The largest NPS units tended to have the most fish species and aquatic habitat but also the greatest amount of alteration. Increasing rates of urbanization, declines in percentage agriculture land cover, and increased density of road-stream crossings in surrounding watersheds were good predictors of nonindigenous species presence within NPS unit boundaries. These results help document the role of NPS units in conserving freshwater fish diversity and, in this region, suggest that measures aimed at controlling urbanization in the adjacent watersheds could affect the diversity of freshwater fish communities in these units.

  3. Genetic evidence of population structuring in the neotropical freshwater fish Brycon hilarii (Valenciennes, 1850).

    PubMed

    Sanches, A; Galetti Jr, P M

    2007-12-01

    Brycon hilarii is a migratory fish widely distributed throughout the Paraguay River Basin. It is appreciated in sport fishing and for its superior meat quality. It is also the main species for tourist attraction in the Bonito region (State of Mato Grosso do Sul, Brazil). Considering the lack of information on the genetic structure of the fish of this species, the aim of the present study was to detect the genetic variability of Brycon hilarii through RAPD markers. A total of eighty specimens collected in different seasons at four sites of the Miranda River sub-basin (Paraguay River Basin, Brazil) were used for analysis. The results of genetic similarity, Shannon diversity, and AMOVA revealed differences between the sampling sites. Through AMOVA, differences between populations were more evident among the animals collected during the non-reproductive season, corresponding to a time of less movement of these fish. A population structuring model in which B. hilarii appears organized into genetically differentiated reproductive units that coexist and co-migrate through the studied system was suggested, contrasting the currently accepted idea that freshwater migratory fish form large panmictic populations in a determined hydrographic system. Despite the lack of a complete picture regarding the distribution of B. hilarii in the studied region, this initial idea on its population genetic structure could be an important contribution to providing aid for management and conservation programs of these fish. PMID:18278356

  4. Risk assessment of trace elements in cultured freshwater fishes from Jiangxi province, China.

    PubMed

    Zhang, Li; Zhang, Dawen; Wei, Yihua; Luo, Linguan; Dai, Tingcan

    2014-04-01

    The levels of trace elements (As, Cd, Cr, Cu, Fe, Ni, Pb, Se, and Zn) in eight species of cultured freshwater fishes from Jiangxi province were determined by inductively coupled plasma-mass spectroscopy. All the studied trace element levels in fish muscles from Jiangxi province did not exceed Chinese national standard and European Union standard, and they were often lower than previous studies. The calculated target hazard quotient values for all the studied trace elements in fish samples were much less than 1, suggesting that the studied trace elements in fish muscles from Jiangxi province had not pose obvious health hazards to consumers. As and Cd concentrations in northern snakehead were much higher than that in other fishes, demonstrating that this fish species could be valuable as a bioindicator of As and Cd in environmental surveys. In addition, the highest concentrations of Fe, Zn, and moderate contents of other essential trace elements in crucian carp indicated that crucian carp could be a good nutrient source of essential trace elements for human health. PMID:24258771

  5. Colossal Aggregations of Giant Alien Freshwater Fish as a Potential Biogeochemical Hotspot

    PubMed Central

    Boulêtreau, Stéphanie; Cucherousset, Julien; Villéger, Sébastien; Masson, Rémi; Santoul, Frédéric

    2011-01-01

    The ubiquity and fascinating nature of animal aggregations are widely recognised. We report here consistent and previously undocumented occurences of aggregations of a giant alien freshwater fish, the Wels catfish (Silurus glanis). Aggregative groups were on average composed of 25 (±10 SD, ranging from 15 to 44) adults with estimated average total biomass of 651 kg (386 – 1132) and biomass density of 23 kg m−2 (14 – 40). Aggregations always occurred within the same location. No foraging, reproductive or anti-predator behaviour were observed during the aggregations. A mass-balance model estimated that these colossal aggregations of an alien species can locally release, through excretion only, up to 70 mg P m−2 h−1 and 400 mg N m−2 h−1, potentially representing the highest biogeochemical hotspots reported in freshwater ecosystems and another unexpected ecological effect of alien species. PMID:21998687

  6. Total and inorganic arsenic in freshwater fish and prawn in Thailand.

    PubMed

    Saipan, Piyawat; Ruangwises, Suthep; Tengjaroenkul, Bundit; Ruangwises, Nongluck

    2012-10-01

    Total and inorganic arsenic levels were determined in 120 samples of eight freshwater animal species collected from five distribution centers in the central region of Thailand between January and March 2011. Eight species with the highest annual catch, consisting of seven fish species and one prawn species, were analyzed. Concentrations of inorganic arsenic (on a wet weight basis) ranged from 0.010 μg/g in giant prawn (Macrobrachium rosenbergii) to 0.230 μg/g in striped snakehead (Channa striata). Climbing perch (Anabas testudineus) exhibited the highest mean concentrations of total arsenic (0.459 ± 0.137 μg/g), inorganic arsenic (0.121 ± 0.044 μg/g), and percentage of inorganic arsenic (26.2%). Inorganic arsenic levels found in freshwater animals in this study were much lower than the Thai regulatory standard of 2 μg/g. PMID:23043844

  7. Life cycle stages of heterophyid trematodes in Vietnamese freshwater fishes traced by molecular and morphometric methods.

    PubMed

    Skov, Jakob; Kania, Per W; Dalsgaard, Anders; Jørgensen, Thomas R; Buchmann, Kurt

    2009-03-01

    A survey of digenean zoonotic trematodes infecting snails and fishes in a North Vietnamese freshwater fish culture system revealed shedding of three types of parapleurolophocercous cercariae from the snail host Melanoides tuberculata and the presence of metacercariae within the genus Haplorchis (H. pumilio and H. taichui) and Procerovum sp. in tissues of cultured fishes (silver carp, Indian carp and climbing perch). No morphological characters were able to link the different cercariae specifically to any of the metacercariae. Subsequent molecular work including PCR and sequencing of ribosomal DNA (the ITS2 region) in cercariae and metacercariae associated only one type of the cercariae to the recovered H. pumilio metacercariae. Further, full identity (100%) was found with regard to the ITS sequence of adult H. pumilio obtained from the same North Vietnamese region. None of the cercariae showed sequence identities with H. taichui but more than 99% identity was found between one cercaria type and the Procerovum sp. metacercaria. It was indicated that trematode parasites of farmed fishes may originate from sources outside the fish ponds and may be introduced as free-swimming cercariae when pond water is being replenished by river water. Likewise, cercariae from the ponds may not always result in metacercarial infections of the farmed fishes. The present study frames the needs for including molecular techniques as auxiliary tools when conducting ecological studies of cercariae in complex ecosystems. The parasites recorded in the fish ponds are not only known to affect the health of aquacultured fishes but also the documented zoonotic potential of the diagnosed metacercaria calls for alerts regarding human consumption of raw or inadequately processed fish dishes. PMID:19056180

  8. Ecotoxicological effects of jute retting on the survival of two freshwater fish and two invertebrates.

    PubMed

    Mondal, Debjit Kumar; Kaviraj, Anilava

    2008-04-01

    Severe deterioration of water quality occurs during jute retting in ponds, canals, floodplain lakes, and other inland water bodies in the rural areas of West Bengal in India. Attempts were made to evaluate changes in the physicochemical parameters of water caused by jute retting, and their impact on the survival of two species of freshwater fish (Labeo rohita and Hypophthalmicthys molitrix) and two species of freshwater invertebrate (Daphnia magna, a Cladocera, and Branchiura sowerbyi, an Oligochaeta). Results showed that jute retting in a pond for 30 days resulted in a sharp increase in the BOD (>1,000 times) and COD (>25 times) of the water, along with a sharp decrease in dissolved oxygen (DO). Free CO(2), total ammonia, and nitrate nitrogen also increased (three to five times) in water as a result of jute retting. Ninety-six-hour static bioassays performed in the laboratory with different dilutions of jute-retting water (JRW) revealed that D. magna and B. sowerbyi were not susceptible to even the raw JRW whereas fingerlings of both species of fish were highly susceptible, L. rohita being more sensitive (96 h LC(50) 37.55% JRW) than H. molitrix (96 h LC(50) 57.54% JRW). Mortality of fish was significantly correlated with the percentage of JRW. PMID:18157635

  9. Linking stream ecology with morphological variability in a native freshwater fish from semi-arid Australia.

    PubMed

    Lostrom, Samantha; Evans, Jonathan P; Grierson, Pauline F; Collin, Shaun P; Davies, Peter M; Kelley, Jennifer L

    2015-08-01

    Environmental variation is a potent force affecting phenotypic expression. While freshwater fishes have provided a compelling example of the link between the environment and phenotypic diversity, few studies have been conducted with arid-zone fishes, particularly those that occur in geographically isolated regions where species typically inhabit intermittent and ephemeral creeks. We investigated morphological variation of a freshwater fish (the western rainbowfish, Melanotaenia australis) inhabiting creeks in the Pilbara region of northwest Australia to determine whether body shape variation correlated with local environmental characteristics, including water velocity, habitat complexity, predator presence, and food availability. We expected that the geographic isolation of creeks within this arid region would result in habitat-specific morphological specializations. We used landmark-based geometric morphometrics to quantify the level of morphological variability in fish captured from 14 locations within three distinct subcatchments of a major river system. Western rainbowfish exhibited a range of morphologies, with variation in body depth accounting for a significant proportion (>42%) of the total variance in shape. Sexual dimorphism was also apparent, with males displaying deeper bodies than females. While the measured local habitat characteristics explained little of the observed morphological variation, fish displayed significant morphological differentiation at the level of the subcatchment. Local adaptation may partly explain the geographic patterns of body shape variation, but fine-scale genetic studies are required to disentangle the effects of genetic differentiation from environmentally determined phenotypic plasticity in body shape. Developing a better understanding of environment-phenotype relationships in species from arid regions will provide important insights into ecological and evolutionary processes in these unique and understudied habitats. PMID

  10. Linking stream ecology with morphological variability in a native freshwater fish from semi-arid Australia

    PubMed Central

    Lostrom, Samantha; Evans, Jonathan P; Grierson, Pauline F; Collin, Shaun P; Davies, Peter M; Kelley, Jennifer L

    2015-01-01

    Environmental variation is a potent force affecting phenotypic expression. While freshwater fishes have provided a compelling example of the link between the environment and phenotypic diversity, few studies have been conducted with arid-zone fishes, particularly those that occur in geographically isolated regions where species typically inhabit intermittent and ephemeral creeks. We investigated morphological variation of a freshwater fish (the western rainbowfish, Melanotaenia australis) inhabiting creeks in the Pilbara region of northwest Australia to determine whether body shape variation correlated with local environmental characteristics, including water velocity, habitat complexity, predator presence, and food availability. We expected that the geographic isolation of creeks within this arid region would result in habitat-specific morphological specializations. We used landmark-based geometric morphometrics to quantify the level of morphological variability in fish captured from 14 locations within three distinct subcatchments of a major river system. Western rainbowfish exhibited a range of morphologies, with variation in body depth accounting for a significant proportion (>42%) of the total variance in shape. Sexual dimorphism was also apparent, with males displaying deeper bodies than females. While the measured local habitat characteristics explained little of the observed morphological variation, fish displayed significant morphological differentiation at the level of the subcatchment. Local adaptation may partly explain the geographic patterns of body shape variation, but fine-scale genetic studies are required to disentangle the effects of genetic differentiation from environmentally determined phenotypic plasticity in body shape. Developing a better understanding of environment–phenotype relationships in species from arid regions will provide important insights into ecological and evolutionary processes in these unique and understudied habitats

  11. Distribution and relationships of As, Cd, Pb and Hg in freshwater fish from five French fishing areas.

    PubMed

    Noël, Laurent; Chekri, Rachida; Millour, Sandrine; Merlo, Mathilde; Leblanc, Jean-Charles; Guérin, Thierry

    2013-02-01

    The concentrations of arsenic, cadmium, mercury and lead in 149 muscle samples of eight freshwater fish species (European eel, bream, common carp, European catfish, roach, perch, pike and pikeperch) from five different French fishing areas from contaminated and control sites were measured by inductively coupled plasma mass spectrometry after microwave digestion under pressure. No significant correlation was found between the condition factor (CF), based on the length-mass relationship, and As, Cd and Pb levels in all the samples analysed, but a positive correlation was detected between CF and Hg levels (P<0.0001, R=0.49). Positive correlations with body length were only found for Hg in roach (P<0.05, R=0.32) and Pb in bream (P<0.05, R=0.48) and correlations with both body weight and length were also found for Hg in pike (P<0.05, R=0.90 and 0.86) and Cd in European eel (P<0.01, R=-0.35 and -0.37). The average content and the standard deviation in fish muscle samples was 0.007±0.012, 0.102±0.077, 0.142±0.097 and 0.035±0.053 mg kg(-1) of wet mass for Cd, As, Hg and Pb, respectively. Significant differences were established between groups of predatory fish and non-predatory fish for Hg and Pb, and between control and contaminated sites in the whole selection and also within feeding guilds, i.e. the values of Hg in the benthophagic fish were significantly different between these sites. Finally, these results were also compared for each species with previous French and European studies. PMID:23177713

  12. Global functional diversity of freshwater fish is concentrated in the Neotropics while functional vulnerability is widespread

    PubMed Central

    Toussaint, A.; Charpin, N.; Brosse, S.; Villéger, S.

    2016-01-01

    Worldwide biodiversity assessments have mainly focused on species richness but little is known about the diversity of species roles, i.e. functional diversity, while this is a key facet to understanding the consequences of global changes on the ecosystem services to human societies. Here, we report the world pattern of functional diversity of freshwater fish using a database encompassing morphological characteristics of more than 9,000 species. The Neotropical realm hosts more than 75% of global functional diversity while other realms each host less than 25%. This discrepancy is mediated by high functional uniqueness in some diversified Neotropical fish orders. Surprisingly, functional diversity patterns were weakly related to functional vulnerability. In the Neotropics the loss of threatened species will cause a limited loss of functional diversity (<10%) whereas in the Nearctic and Palearctic realms, decline of the functional diversity will reach 43% and 33%, respectively, conferring a high functional vulnerability to these realms. Conservation of the Neotropical fish diversity is a key target to maintain world fish functional diversity, but this should not hide the pressing need to conserve the vulnerable fish faunas of the rest of the world, in which functional diversity is to a large extent supported by threatened species. PMID:26980070

  13. New and previously described species of Dactylogyridae (Monogenoidea) from the gills of Panamanian freshwater fishes (Teleostei).

    PubMed

    Mendoza-Franco, Edgar F; Aguirre-Macedo, M Leopoldina; Vidal-Martínez, Victor M

    2007-08-01

    During an investigation of the diversity of metazoan parasites of 7 freshwater fish species from 3 localities in central Panama, the following gill dactylogyrid (Monogenoidea) species were found: Aphanoblastella chagresii n. sp. from Pimelodella chagresi (Heptapteridae); Aphanoblastella travassosi (Price, 1938) Kritsky, Mendoza-Franco, and Scholz, 2000 from Rhamdia quelen (Heptapteridae); Diaphorocleidus petrosusi n. sp. from Brycon petrosus (Characidae); Gussevia asota Kritsky, Thatcher, and Boeger, 1989, from Astronotus ocellatus (Cichlidae); Sciadicleithrum panamensis n. sp. from Aequidens coeruleopunctatus (Cichlidae); Urocleidoides flegomai n. sp. from Piabucina panamensis (Lebiasinidae); and Urocleidoides similuncus n. sp. from Poecilia gillii (Poeciliidae). Consideration of the comparative morphology and distribution of these parasites along with the evolutionary history of the host fishes suggests that diversification may be associated with geotectonic events that provided isolation of the Central American fauna with the uplift of the Panamanian Isthmus during early Pliocene (3 mya). PMID:17918354

  14. Mercury in freshwater fish and clams from the Cerro Prieto geothermal field of Baja California, Mexico

    SciTech Connect

    Gutierrez-Galindo, E.A.; Munoz, G.F.; Flores, A.A.

    1988-08-01

    Several reports have expressed concern about the potential toxicity hazards and environmental contamination of mercury emissions from geothermal fields in Hawaii, New Zealand, Iceland, California and Mexico. Inorganic mercury discharged from the sources may accumulate in the sediments of rivers or lakes and, after microbiological methylation may become concentrated in the edible tissue of fish. This study involves assessment of geothermal mercury pollution arising from Cerro Prieto. For this purpose the fish Tilapia mossambica and the clam Corbicula fluminea were collected from the freshwater courses of the Mexicali Valley. Reports indicated that in 1982, 13 t of T. mossambica were destinated for human consumption. A further aim was to provide base line data and information relevant to the level of mercury contamination for the Mexicali Valley.

  15. Phylogenetic diversity and biological activity of culturable Actinobacteria isolated from freshwater fish gut microbiota.

    PubMed

    Jami, Mansooreh; Ghanbari, Mahdi; Kneifel, Wolfgang; Domig, Konrad J

    2015-06-01

    The diversity of Actinobacteria isolated from the gut microbiota of two freshwater fish species namely Schizothorax zarudnyi and Schizocypris altidorsalis was investigated employing classical cultivation techniques, repetitive sequence-based PCR (rep-PCR), partial and full 16S rDNA sequencing followed by phylogenetic analysis. A total of 277 isolates were cultured by applying three different agar media. Based on rep-PCR profile analysis a subset of 33 strains was selected for further phylogenetic investigations, antimicrobial activity testing and diversity analysis of secondary-metabolite biosynthetic genes. The identification based on 16S rRNA gene sequencing revealed that the isolates belong to eight genera distributed among six families. At the family level, 72% of the 277 isolates belong to the family Streptomycetaceae. Among the non-streptomycetes group, the most dominant group could be allocated to the family of Pseudonocardiaceae followed by the members of Micromonosporaceae. Phylogenetic analysis clearly showed that many of the isolates in the genera Streptomyces, Saccharomonospora, Micromonospora, Nocardiopsis, Arthrobacter, Kocuria, Microbacterium and Agromyces formed a single and distinct cluster with the type strains. Notably, there is no report so far about the occurrence of these Actinobacteria in the microbiota of freshwater fish. Of the 33 isolates, all the strains exhibited antibacterial activity against a set of tested human and fish pathogenic bacteria. Then, to study their associated potential capacity to synthesize diverse bioactive natural products, diversity of genes associated with secondary-metabolite biosynthesis including PKS I, PKS II, NRPS, the enzyme PhzE of the phenazine pathways, the enzyme dTGD of 6-deoxyhexoses glycosylation pathway, the enzyme Halo of halogenation pathway and the enzyme CYP in polyene polyketide biosynthesis were investigated among the isolates. All the strains possess at least two types of the investigated

  16. Biochemical responses in freshwater fish after exposure to water-soluble fraction of gasoline.

    PubMed

    Bettim, Franciele Lima; Galvan, Gabrieli Limberger; Cestari, Marta Margarete; Yamamoto, Carlos Itsuo; de Assis, Helena Cristina Silva

    2016-02-01

    The water-soluble fraction of gasoline (WSFG) is a complex mixture of mono-polycyclic aromatic hydrocarbons. The study aimed to evaluate the effects of WSFG diluted 1.5% on freshwater fish. Astyanax altiparanae were exposed to the WSFG for 96 h, under a semi-static system, with renewal of 25% of the gasoline test solution every 24 h. In addition, a decay of the contamination (DC) was carried out. During DC, the fish was exposed to the WSFG for 8 d, followed by another 7 d with renewal of 25% of volume aquaria with clean water every 24 h. For depuration, fish were transferred to aquaria with clean water, and in addition, 25% of the water was replaced every 24 h. The liver and kidney biotransformation, antioxidant defenses and lipid peroxidation (LPO) levels were evaluated. In the liver, the WSFG 1.5% caused reduction of glutathione S-transferase (GST) after 96 h and DC. In the kidney, only in depuration an increased GST activity was observed, and after DC a higher LPO levels. An increase of the superoxide dismutase (SOD) activity occurred at 96 h in both tissues; however, in the liver was also observed during the depuration. In WSFG 96 h, the glutathione peroxidase (GPx) activity in the kidney increased. As biomarkers of neurotoxicity, the brain and muscle acetylcholinesterase activities were measured, but the WSFG 1.5% did not change them. Therefore, this study brought forth more data about WSFG effects on freshwater fish after lower concentrations exposure and a DC, simulating an environmental contamination. PMID:26495832

  17. (90)Sr in fish from the southern Baltic Sea, coastal lagoons and freshwater lake.

    PubMed

    Zalewska, Tamara; Saniewski, Michał; Suplińska, Maria; Rubel, Barbara

    2016-07-01

    Activity concentrations of radioactive (90)Sr were studied in four fish species: herring, flounder, sprat and cod caught in the southern Baltic Sea in two periods: 2005-2009 and 2013-2014. The study included also perch from the coastal lagoons - Vistula Lagoon and Szczcin Lagoon and a freshwater lake - Żarnowieckie Lake as well as additional lake species: pike and bream. (90)Sr activity concentrations were compared in relation to species and to particular tissue: muscle, whole fish (eviscerated) and bones. In 2014, in the Baltic, the maximal (90)Sr concentrations were found in fishbones: herring - 0.39 Bq kg(-1) w.w., cod - 0.48 Bq kg(-1) w.w., and flounder - 0.54 Bq kg(-1) w.w. In the whole fish the maximal concentrations were found in flounder - 0.16 Bq kg(-1) w.w. and cod - 0.15 Bq kg(-1) w.w., while in herring - 0.022 Bq kg(-1) w.w. and sprat - 0.026 Bq kg(-1) w.w. they stayed at lower level. Relatively high (90)Sr concentrations were detected in whole fish from freshwater Lake Żarnowieckie: perch - 0.054 Bq kg(-1) w.w., pike - 0.062 Bq kg(-1) w.w. and bream - 0.140 Bq kg(-1) w.w. Concentration ratio (CR) determined for particular fish tissues and for whole eviscerated fish in relation to (90)Sr concentrations in seawater and lake water were showing significant variability unlike the corresponding (137)Cs concentration ratios which are stable and specific for fish species. The study corroborates with the conviction of the growing role of (90)Sr in the overall radioactivity in the southern Baltic Sea as compared to (137)Cs. PMID:27061778

  18. Community ecology of the metazoan parasites of freshwater fishes of Kerala.

    PubMed

    Beevi, M Razia; Radhakrishnan, S

    2012-10-01

    The prevalence and mean intensity of metazoan parasite infection, the community characteristics (richness index, dominance index, evenness index and Shannon index of diversity) and the qualitative similarity of the metazoan parasite fauna among the species and families of the fishes were determined of 13 fish species of freshwater fishes of Kerala belonging to seven families. The metazoan parasite fauna of this geographical area is very diverse; it consisted of 33 species of parasites belonging to seven major taxa: ten species of Monogenea, nine Digenea, two Cestoda, six Nematoda, three Acanthocephala, two Copepoda and one Isopoda. Prevalence of infection ranged from 32.9% (Puntius vittatus) to 87.1% (Mystus oculatus) and mean intensity from 3.8 (Puntius vittatus) to 27.6 (Aplocheilus lineatus). The infra- and component communities of parasites were somewhat characteristic. The dominance pattern of the major taxa was in the order Digenea > Nematoda > Monogenea = Acanthocephala > Cestoda = Copepoda > Isopoda. Macropodus cupanus harboured the richest fauna and Puntius vittatus had the least rich fauna. The parasite fauna of A. lineatus was the most heterogeneous and that of M. cavasius, the most homogeneous. The diversity of the parasite fauna was the greatest in M. cavasius and the least in A. lineatus. The parasite faunas of A. lineatus and M. cupanus and of M. cavasius and M. oculatus were similar. However, in spite of the taxonomic nearness and the similarity of the habits and habitats of the four species of cyprinids (P. amphibius, P. filamentosus, P. sarana and P. vittatus), their parasite fauna were qualitatively very dissimilar-of the seven species of parasites encountered in them only one was shared by the four host species. The cyprinid, Rasbora daniconius, had its own characteristic component community of parasites consisting of six species none of which was shared by the other four cyprinids. The richest parasite fauna was that of the family

  19. Trematode diversity in freshwater fishes of the Globe II: 'New World'.

    PubMed

    Choudhury, Anindo; Aguirre-Macedo, M Leopoldina; Curran, Stephen S; de Núñez, Margarita Ostrowski; Overstreet, Robin M; de León, Gerardo Pérez-Ponce; Santos, Cláudia Portes

    2016-03-01

    We provide a summary overview of the diversity of trematode parasites in freshwater fishes of the 'New World', i.e. the Americas, with emphasis on adult forms. The trematode fauna of three regions, South America, Middle America, and USA and Canada (North America north of Mexico), are considered separately. In total, 462 trematode species have been reported as adults from the Americas. The proportion of host species examined for parasites varies widely across the Americas, from a high of 45% in the Mexican region of Middle America to less than 5% in South America. North and South America share no adult species, and one exclusively freshwater genus, Creptotrema Travassos, Artigas & Pereira, 1928 in the Allocreadiidae Looss, 1902 is the most widely distributed. Metacercariae of strigeiforms maturing in fish-eating birds (e.g. species of the Diplostomidae Poirier, 1886) are common and widely distributed. The review also highlights the paucity of known life-cycles. The foreseeable future of diversity studies belongs to integrative approaches and the application of molecular ecological methods. While opportunistic sampling will remain important in describing and cataloguing the trematode fauna, a better understanding of trematode diversity and biology will also depend on strategic sampling throughout the Americas. PMID:26898590

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

    USGS Publications Warehouse

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

    2005-01-01

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

  1. The cold-water connection: Bergmann's rule in North American freshwater fishes.

    PubMed

    Rypel, Andrew L

    2014-01-01

    Understanding general rules governing macroecological body size variations is one of the oldest pursuits in ecology. However, this science has been dominated by studies of terrestrial vertebrates, spurring debate over the validity of such rules in other taxonomic groups. Here, relationships between maximum body size and latitude, temperature, and elevation were evaluated for 29 North American freshwater fish species. Bergmann's rule (i.e., that body size correlates positively with latitude and negatively with temperature) was observed in 38% of species, converse Bergmann's rule (that body size correlates negatively with latitude and positively with temperature) was observed in 34% of species, and 28% of species showed no macroecological body size relationships. Most notably, every species that expressed Bergmann's rule was a cool- or cold-water species while every species that expressed converse Bergmann's rule was a warm-water species, highlighting how these patterns are likely connected to species thermal niches. This study contradicts previous research suggesting Bergmann's rule does not apply to freshwater fishes, and is congruent with an emerging paradigm of variable macroecological body size patterns in poikilotherms. PMID:24334744

  2. Chronic Effects of Realistic Concentrations of Non-essential and Essential Metals (Lead and Zinc) on Oxidative Stress Biomarkers of the Mosquitofish, Gambusia holbrooki.

    PubMed

    Nunes, Bruno; Caldeira, Carina; Luísa Pereira, Joana; Gonçalves, Fernando; Correia, Alberto Teodorico

    2015-11-01

    Metallic contamination is widespread, particularly in areas impacted by human activities. Human activities result in high loads of metals being discarded into the aquatic compartment, reinforcing the need to evaluate their toxic effects especially on exposed fish. The purpose of this study was to determine the toxic response (namely, antioxidant levels and lipoperoxidative damage) in both liver and gills of the freshwater fish species Gambusia holbrooki, exposed to lead and zinc. Fish were exposed for 28 days (chronic exposure) to ecologically relevant concentrations of the selected compounds. The following oxidative stress/damage biomarkers were evaluated: glutathione-S-transferases (GSTs), glutathione reductase (GR), and thiobarbituric acid reactive substances (TBARS). The results indicate that lead caused a significant oxidative response, with significant increase of the enzymatic antioxidant defense (GSTs activity in hepatic tissue, and GR activity in branchial tissue) of exposed organisms. On the other hand, zinc caused a significant inhibition of G. holbrooki hepatic GR, a biological response that may be related to the antioxidant activity exhibited by this metal. The obtained results are of high importance, especially if one considers that the obtained toxic responses occurred at low, albeit ecologically relevant, levels of exposure. PMID:26184506

  3. Effects of ecologically relevant concentrations of cadmium in a freshwater fish.

    PubMed

    Pereira, L S; Ribas, J L C; Vicari, T; Silva, S B; Stival, J; Baldan, A P; Valdez Domingos, F X; Grassi, M T; Cestari, M M; Silva de Assis, H C

    2016-08-01

    Sub-chronic effects of ecologically relevant concentrations of cadmium (Cd) were evaluated in the catfish Rhamdia quelen. The fish were exposed to Cd (0, 0.1, 1, 10 and 100μgL(-1)) for 15 days. Bioconcentration was observed in the liver of fish exposed to 10 and 100μgL(-1) of cadmium. The liver glutathione S-transferase activity decreased at 0.1 and 1μgL(-1) and increased at 100μgL(-1) and lipoperoxidation increased in all tested concentrations. Fish exposed to 0.1, 1 and 100µgL(-1) Cd presented increase in hepatic lesion index. In the kidney, the catalase activity and LPO reduced in all exposed groups. The gluthatione peroxidase, etoxiresorufin-O-deethylase activities and metallothionein increased at the highest concentration of Cd, but the level of reduced glutathione decreased. The genotoxicity was observed at 0.1 and 100μgL(-1). Neurotoxicity was not observed. The results showed that low concentrations (range of μgL(-1)) of Cd caused hepato-, nephro- and hematological alterations in this freshwater fish species. PMID:27062343

  4. Evaluation of a method for quantifying eugenol concentrations in the fillet tissue from freshwater fish species

    USGS Publications Warehouse

    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.

  5. Sperm quality and cryopreservation of Brazilian freshwater fish species: a review.

    PubMed

    Viveiros, A T M; Godinho, H P

    2009-03-01

    The Brazilian freshwater fish diversity is the richest in the world. Only 0.7% of all Brazilian species have had any aspect of their sperm biology addressed up to this date. The majority of the fish species described in this review migrate during the spawning season (a phenomenon known as piracema). Urbanization, pollution, hydroelectric dams and deforestation are some of the causes of stock depletion or even local extinction of some of these species. The knowledge concerning sperm quality and minimum sperm:egg ratio is important to maximize the use of males without reducing hatching rates. Furthermore, sperm cryopreservation and gene banking can guarantee the conservation of genetic diversity and development of adequate breeding programs of native fish species. In this review, we present and evaluate the existing information on Brazilian fish species that have been subject to sperm quality and cryopreservation studies. The following parameters were evaluated: volume of extractable sperm, sperm motility, sperm concentration, freezing media, freezing methods, and post-thaw sperm quality. Although the existing protocols yield relatively high post-thaw motility and fertilization rates, the use of cryopreserved sperm in routine hatchery production is still limited in Brazil. PMID:19189240

  6. Bioconcentration and Acute Intoxication of Brazilian Freshwater Fishes by the Methyl Parathion Organophosphate Pesticide

    PubMed Central

    Bosco de Salles, João; Matos Lopes, Renato; de Salles, Cristiane M. C.; Cassano, Vicente P. F.; de Oliveira, Manildo Marcião; Cunha Bastos, Vera L. F.; Bastos, Jayme Cunha

    2015-01-01

    Three species of freshwater Brazilian fishes (pacu, Piaractus mesopotamicus; piavussu, Leporinus macrocephalus, and curimbatá, Prochilodus lineatus) were exposed to an acute dose of 5 ppm methyl parathion organophosphate pesticide. Three to five individuals per species were exposed, one at a time, to 40 liters tap water spiked with Folidol 600. Pesticide concentrations and cholinesterase (ChE) activities were evaluated in serum, liver, brain, heart, and muscle. The bioconcentration of methyl parathion was similar for all studied fishes. Brain tissue showed the highest pesticide concentration, reaching 80 ppm after exposure for 30 min to methyl parathion. Three to 5 hours of 5 ppm methyl parathion exposure provoked the death of all P. lineatus at 92% brain AChE inhibition, whereas fish from the other two species survived for up to 78 hours with less than 80% brain AChE inhibition. Our results indicate that acute toxic effects of methyl parathion to fish are correlated with brain AChE sensitivity to methyl paraoxon. PMID:26339593

  7. Bioconcentration and Acute Intoxication of Brazilian Freshwater Fishes by the Methyl Parathion Organophosphate Pesticide.

    PubMed

    de Salles, João Bosco; Lopes, Renato Matos; de Salles, Cristiane M C; Cassano, Vicente P F; de Oliveira, Manildo Marcião; Bastos, Vera L F Cunha; Bastos, Jayme Cunha

    2015-01-01

    Three species of freshwater Brazilian fishes (pacu, Piaractus mesopotamicus; piavussu, Leporinus macrocephalus, and curimbatá, Prochilodus lineatus) were exposed to an acute dose of 5 ppm methyl parathion organophosphate pesticide. Three to five individuals per species were exposed, one at a time, to 40 liters tap water spiked with Folidol 600. Pesticide concentrations and cholinesterase (ChE) activities were evaluated in serum, liver, brain, heart, and muscle. The bioconcentration of methyl parathion was similar for all studied fishes. Brain tissue showed the highest pesticide concentration, reaching 80 ppm after exposure for 30 min to methyl parathion. Three to 5 hours of 5 ppm methyl parathion exposure provoked the death of all P. lineatus at 92% brain AChE inhibition, whereas fish from the other two species survived for up to 78 hours with less than 80% brain AChE inhibition. Our results indicate that acute toxic effects of methyl parathion to fish are correlated with brain AChE sensitivity to methyl paraoxon. PMID:26339593

  8. Evaluation of a Method for Quantifying Eugenol Concentrations in the Fillet Tissue from Freshwater Fish Species.

    PubMed

    Meinertz, Jeffery R; Schreier, Theresa M; Porcher, Scott T; Smerud, Justin R

    2016-03-01

    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. PMID:27010409

  9. Can backcalculation models unravel complex larval growth histories in a tropical freshwater fish?

    PubMed

    Starrs, D; Ebner, B C; Fulton, C J

    2013-07-01

    This experimental study compared the precision and accuracy of the biological intercept (BI), modified fry (MF) and time-varying growth (TVG) backcalculation models in estimating the early growth of the tropical freshwater purple-spotted gudgeon Mogurnda adspersa. Larvae were reared up to 41 days post hatching under two temperatures and four different feeding regimes. Food and temperature treatments induced complex growth profiles among fish, and although total length (LT ) and otolith radius were related under all conditions, some uncoupling was evident in the otolith-somatic-growth (OSG) relationship of fish subjected to periods of changing food availability. Furthermore, otolith growth was found to be significantly influenced by temperature, but not by food availability. Analysis of backcalculation residuals by linear mixed effects modelling revealed that BI and TVG were equally precise in predicting somatic growth, with the highest accuracy provided by TVG. The performance of all the three models declined as the OSG relationship weakened under low-food conditions, with maximum errors estimated to be 39, 60 and 36% of observed LT for the BI, MF and TVG models, respectively. The need for careful validation of backcalculation models is emphasized when examining fishes subjected to variable environmental conditions, and when exploring the differential influence of temperature and food on fish LT and otolith growth. PMID:23808694

  10. An eDNA Assay to Monitor a Globally Invasive Fish Species from Flowing Freshwater.

    PubMed

    Adrian-Kalchhauser, Irene; Burkhardt-Holm, Patricia

    2016-01-01

    Ponto-Caspian gobies are a flock of five invasive fish species that have colonized freshwaters and brackish waters in Europe and North America. One of them, the round goby Neogobius melanostomus, figures among the 100 worst invaders in Europe. Current methods to detect the presence of Ponto-Caspian gobies involve catching or sighting the fish. These approaches are labor intense and not very sensitive. Consequently, populations are usually detected only when they have reached high densities and when management or containment efforts are futile. To improve monitoring, we developed an assay based on the detection of DNA traces (environmental DNA, or eDNA) of Ponto-Caspian gobies in river water. The assay specifically detects invasive goby DNA and does not react to any native fish species. We apply the assay to environmental samples and demonstrate that parameters such as sampling depth, sampling location, extraction protocol, PCR protocol and PCR inhibition greatly impact detection. We further successfully outline the invasion front of Ponto-Caspian gobies in a large river, the High Rhine in Switzerland, and thus demonstrate the applicability of the assay to lotic environments. The eDNA assay requires less time, equipment, manpower, skills, and financial resources than the conventional monitoring methods such as electrofishing, angling or diving. Samples can be taken by untrained individuals, and the assay can be performed by any molecular biologist on a conventional PCR machine. Therefore, this assay enables environment managers to map invaded areas independently of fishermen's' reports and fish community monitorings. PMID:26814998

  11. Circannual rhythms of acetylcholinesterase (AChE) activity in the freshwater fish Cnesterodon decemmaculatus.

    PubMed

    Menéndez-Helman, Renata J; Ferreyroa, Gisele V; dos Santos Afonso, Maria; Salibián, Alfredo

    2015-01-01

    The use of biomarkers as a tool to assess responses of organisms exposed to pollutants in toxicity bioassays, as well as in aquatic environmental risk assessment protocols, requires the understanding of the natural fluctuation of the particular biomarker. The aim of this study was to characterize the intrinsic variations of acetylcholinesterase (AChE) activity in tissues of a native freshwater teleost fish to be used as biomarker in toxicity tests, taking into account both seasonal influence and fish size. Specific AChE activity was measured by the method of Ellman et al. (1961) in homogenates of fish anterior section finding a seasonal variability. The highest activity was observed in summer, decreasing significantly below 40% in winter. The annual AChE activity cycle in the anterior section was fitted to a sinusoidal function with a period of 11.2 months. Moreover, an inverse relationship between enzymatic activity and the animal size was established. The results showed that both the fish length and seasonal variability affect AChE activity. AChE activity in fish posterior section showed a similar trend to that in the anterior section, while seasonal variations of the activity in midsection were observed but differences were not statistically significant. In addition, no relationship between AChE and total tissue protein was established in the anterior and posterior sections suggesting that the circannual rhythms observed are AChE-specific responses. Results highlight the importance of considering both the fish size and season variations to reach valid conclusions when AChE activity is employed as neurotoxicity biomarker. PMID:25450939

  12. Mitigating the impact of oil-palm monoculture on freshwater fishes in Southeast Asia.

    PubMed

    Giam, Xingli; Hadiaty, Renny K; Tan, Heok Hui; Parenti, Lynne R; Wowor, Daisy; Sauri, Sopian; Chong, Kwek Yan; Yeo, Darren C J; Wilcove, David S

    2015-10-01

    Anthropogenic land-cover change is driving biodiversity loss worldwide. At the epicenter of this crisis lies Southeast Asia, where biodiversity-rich forests are being converted to oil-palm monocultures. As demand for palm oil increases, there is an urgent need to find strategies that maintain biodiversity in plantations. Previous studies found that retaining forest patches within plantations benefited some terrestrial taxa but not others. However, no study has focused on aquatic taxa such as fishes, despite their importance to human well-being. We assessed the efficacy of forested riparian reserves in conserving freshwater fish biodiversity in oil-palm monoculture by sampling stream fish communities in an oil-palm plantation in Central Kalimantan, Indonesia. Forested riparian reserves maintained preconversion local fish species richness and functional diversity. In contrast, local and total species richness, biomass, and functional diversity declined markedly in streams without riparian reserves. Mechanistically, riparian reserves appeared to increase local species richness by increasing leaf litter cover and maintaining coarse substrate. The loss of fishes specializing in leaf litter and coarse substrate decreased functional diversity and altered community composition in oil-palm plantation streams that lacked riparian reserves. Thus, a land-sharing strategy that incorporates the retention of forested riparian reserves may maintain the ecological integrity of fish communities in oil-palm plantations. We urge policy makers and growers to make retention of riparian reserves in oil-palm plantations standard practice, and we encourage palm-oil purchasers to source only palm oil from plantations that employ this practice. PMID:25800305

  13. Higher freshwater fish and sea fish intake is inversely associated with colorectal cancer risk among Chinese population: a case-control study

    PubMed Central

    Xu, Ming; Fang, Yu-Jing; Chen, Yu-Ming; Lu, Min-Shan; Pan, Zhi-Zhong; Yan, Bo; Zhong, Xiao; Zhang, Cai-Xia

    2015-01-01

    The association between specific fish intake and colorectal cancer risk remains controversial. This study aimed to examine the association between specific fish intake and colorectal cancer risk in Chinese population in a large case control study. During July 2010 to November 2014, 1189 eligible colorectal cancer cases and 1189 frequency-matched controls (age and sex) completed in-person interviews. A validated food frequency questionnaire was used to estimate dietary intake. Multivariate logistical regression models were used to estimate the odds ratio (OR) and 95% confidence interval (95% CI) after adjusting for various confounders. A strong inverse association was found between freshwater fish intake and colorectal cancer risk. Compared with the lowest quartile, the highest quartile intake showed a risk reduction of 53% (OR 0.47, 95% CI = 0.36–0.60, Ptrend < 0.01) after adjustment for various confounders. The inverse association were also observed for sea fish (OR 0.79, 95%CI = 0.62–0.99, Ptrend < 0.01) and fresh fish (OR 0.49, 95%CI = 0.38–0.62, Ptrend < 0.01). No statistically significant association was found between dried/salted fish and shellfish intake and colorectal cancer risk. These results indicate that higher consumption of freshwater fish, sea fish and fresh fish is associated with a lower risk of colorectal caner. PMID:26264963

  14. The impacts of stress on sodium metabolism and copper accumulation in a freshwater fish.

    PubMed

    Harley, Rachel A; Glover, Chris N

    2014-02-01

    In freshwater fish, stress can often result in significant modifications to Na(+) metabolism and may be an important aspect to consider in conservation efforts; as maintaining ion balance is critical to survival and ion transport is also a key determinant of metal toxicity. In order to better quantify the response of stress, Na(+) influx, Na(+) efflux, and copper accumulation were measured as a result of handling stress in inanga (Galaxias maculatus). This species is a culturally and economically important fish in New Zealand as one of the major species in the local 'whitebait' fishery. Na(+) influx rates in inanga were found to be 2-3 times greater after handling than in 'recovered' fish, and Na(+) efflux rates increased in the range of 5-6 times. Both influx and efflux rates quickly returned to resting levels within 24h. Increases in Na(+) efflux were strongly correlated with opercular beat frequency. This suggests an increas in ventilation, and subsequent enhanced diffusive loss of Na(+), as the mechanism of increased Na(+) efflux. Total body copper levels were also measured under similar treatments. Fish had significantly higher levels of copper directly after handling than following a 24h recovery; likely due to a shared Na(+)/copper uptake pathway. As accumulation is linked to toxicity, fish exposed to elevated copper levels in stressful environments will consequently be more at risk to metal toxicity. In a natural environment, stress can come from many different sources; among which, anthropogenic disturbances can often be a cause. Given that inanga must migrate through metal-contaminated coastal regions to reach breeding habitats, they will be exposed to toxicants under conditions where perfusion and ventilation of the gill is increased. As such, ion loss would be exacerbated, leading to an enhanced compensatory ion uptake and an increase in accumulation of ion-mimicking toxicants such as copper, exacerbating toxicity. This is a concern as conservation

  15. A Qualitative Meta-Analysis Reveals Consistent Effects of Atrazine on Freshwater Fish and Amphibians

    PubMed Central

    Rohr, Jason R.; McCoy, Krista A.

    2010-01-01

    Objective The biological effects of the herbicide atrazine on freshwater vertebrates are highly controversial. In an effort to resolve the controversy, we conducted a qualitative meta-analysis on the effects of ecologically relevant atrazine concentrations on amphibian and fish survival, behavior, metamorphic traits, infections, and immune, endocrine, and reproductive systems. Data sources We used published, peer-reviewed research and applied strict quality criteria for inclusion of studies in the meta-analysis. Data synthesis We found little evidence that atrazine consistently caused direct mortality of fish or amphibians, but we found evidence that it can have indirect and sublethal effects. The relationship between atrazine concentration and timing of amphibian metamorphosis was regularly nonmonotonic, indicating that atrazine can both accelerate and delay metamorphosis. Atrazine reduced size at or near metamorphosis in 15 of 17 studies and 14 of 14 species. Atrazine elevated amphibian and fish activity in 12 of 13 studies, reduced antipredator behaviors in 6 of 7 studies, and reduced olfactory abilities for fish but not for amphibians. Atrazine was associated with a reduction in 33 of 43 immune function end points and with an increase in 13 of 16 infection end points. Atrazine altered at least one aspect of gonadal morphology in 7 of 10 studies and consistently affected gonadal function, altering spermatogenesis in 2 of 2 studies and sex hormone concentrations in 6 of 7 studies. Atrazine did not affect vitellogenin in 5 studies and increased aromatase in only 1 of 6 studies. Effects of atrazine on fish and amphibian reproductive success, sex ratios, gene frequencies, populations, and communities remain uncertain. Conclusions Although there is much left to learn about the effects of atrazine, we identified several consistent effects of atrazine that must be weighed against any of its benefits and the costs and benefits of alternatives to atrazine use. PMID

  16. Spatial Representativeness of Environmental DNA Metabarcoding Signal for Fish Biodiversity Assessment in a Natural Freshwater System

    PubMed Central

    Civade, Raphaël; Dejean, Tony; Valentini, Alice; Roset, Nicolas; Raymond, Jean-Claude; Bonin, Aurélie; Taberlet, Pierre; Pont, Didier

    2016-01-01

    In the last few years, the study of environmental DNA (eDNA) has drawn attention for many reasons, including its advantages for monitoring and conservation purposes. So far, in aquatic environments, most of eDNA research has focused on the detection of single species using species-specific markers. Recently, species inventories based on the analysis of a single generalist marker targeting a larger taxonomic group (eDNA metabarcoding) have proven useful for bony fish and amphibian biodiversity surveys. This approach involves in situ filtering of large volumes of water followed by amplification and sequencing of a short discriminative fragment from the 12S rDNA mitochondrial gene. In this study, we went one step further by investigating the spatial representativeness (i.e. ecological reliability and signal variability in space) of eDNA metabarcoding for large-scale fish biodiversity assessment in a freshwater system including lentic and lotic environments. We tested the ability of this approach to characterize large-scale organization of fish communities along a longitudinal gradient, from a lake to the outflowing river. First, our results confirm that eDNA metabarcoding is more efficient than a single traditional sampling campaign to detect species presence, especially in rivers. Second, the species list obtained using this approach is comparable to the one obtained when cumulating all traditional sampling sessions since 1995 and 1988 for the lake and the river, respectively. In conclusion, eDNA metabarcoding gives a faithful description of local fish biodiversity in the study system, more specifically within a range of a few kilometers along the river in our study conditions, i.e. longer than a traditional fish sampling site. PMID:27359116

  17. Homogenization dynamics and introduction routes of invasive freshwater fish in the Iberian Peninsula.

    PubMed

    Clavero, Miguel; García-Berthou, Emili

    2006-12-01

    Nonnative invasive species are one of the main global threats to biodiversity. The understanding of the traits characterizing successful invaders and invasion-prone ecosystems is increasing, but our predictive ability is still limited. Quantitative information on biotic homogenization and particularly its temporal dynamics is even scarcer. We used freshwater fish distribution data in the Iberian Peninsula in four periods (before human intervention, 1991, 1995, and 2001) to assess the temporal dynamics of biotic homogenization among river basins. The percentage of introduced species among fish faunas has increased in recent times (from 41.8% in 1991 to 52.5% in 2001), leading to a clear increase in the similarity of community composition among basins. The mean Jaccard's index increase (a measure of biotic homogenization) from the pristine situation to the present (17.1%) was similar to that for Californian fish but higher than for other studies. However, biotic homogenization was found to be a temporally dynamic process, with finer temporal grain analyses detecting transient stages of biotic differentiation. Introduced species assemblages were spatially structured along a latitudinal gradient in the Iberian Peninsula, with species related to sport fishing being characteristic of northern basins. Although the comparison of fish distributions in the Iberian Peninsula and France showed significant and generalized biotic homogenization, nonnative assemblages of northeastern Iberian basins were more similar to those of France than to those of the rest of the Iberian Peninsula, indicating a main introduction route. Species introduced to the Iberian Peninsula tended to be mainly piscivores or widely introduced species that previously had been introduced to France. Our results indicate that the simultaneous analysis of the spatial distribution of introduced assemblages (excluding native species that reflect other biogeographical patterns) and their specific traits can be an

  18. Restoration and colonization of freshwater mussels and fish in a southeastern United States tailwater

    USGS Publications Warehouse

    Layzer, J.B.; Scott, E.M., Jr.

    2006-01-01

    The French Broad River originates in North Carolina, flows west into Tennessee and at its confluence with the Holston River forms the Tennessee River. Douglas Dam, located on the French Broad River 52 km above its mouth, is operated primarily for peaking hydroelectric power and flood control. Prior to completion of the dam in 1943, the lower French Broad River contained about 53 species of freshwater mussels and 100 species of fish. By 1977, the fauna in the 52-km-long tailwater was reduced to 12 species of mussels and 42 native species of fish. Improvements in tailwater conditions occurred following initiation of minimum flows in 1987, and consistent reaeration of discharge in 1993. From 1988 to 2002, we sampled three sites (4, 28, and 39 km downstream of the dam) to monitor the fish assemblage. Each year since 1988, we have collected one or more additional species, indicating continued immigration. We collected 82 native and 9 exotic species of fish overall, but the maximum of 67 species in 1 year suggests that some species reside in the tailwater at low densities or all immigrants may not successfully colonize the tailwater. There is limited potential for most extirpated species of mussels to naturally recolonize the tailwater because source populations are isolated. Consequently, 19 754 adult mussels of 19 species were introduced between 1997 and 2000. Survival of translocated mussels has been high, and successful reproduction of at least one translocated species has occurred. Additionally, four mussel species are naturally colonizing the tailwater. Colonization and recruitment of additional mussel species is expected as populations of their host fishes increase. We believe that the improved conditions of the tailwater may allow for the re-establishment of sustaining populations of 30 mussel species of historic occurrence, but the continued operation of Douglas Dam as a peaking hydroelectric project will reduce the probability of successfully reintroducing some

  19. Using Historical Atlas Data to Develop High-Resolution Distribution Models of Freshwater Fishes

    PubMed Central

    Huang, Jian; Frimpong, Emmanuel A.

    2015-01-01

    Understanding the spatial pattern of species distributions is fundamental in biogeography, and conservation and resource management applications. Most species distribution models (SDMs) require or prefer species presence and absence data for adequate estimation of model parameters. However, observations with unreliable or unreported species absences dominate and limit the implementation of SDMs. Presence-only models generally yield less accurate predictions of species distribution, and make it difficult to incorporate spatial autocorrelation. The availability of large amounts of historical presence records for freshwater fishes of the United States provides an opportunity for deriving reliable absences from data reported as presence-only, when sampling was predominantly community-based. In this study, we used boosted regression trees (BRT), logistic regression, and MaxEnt models to assess the performance of a historical metacommunity database with inferred absences, for modeling fish distributions, investigating the effect of model choice and data properties thereby. With models of the distribution of 76 native, non-game fish species of varied traits and rarity attributes in four river basins across the United States, we show that model accuracy depends on data quality (e.g., sample size, location precision), species’ rarity, statistical modeling technique, and consideration of spatial autocorrelation. The cross-validation area under the receiver-operating-characteristic curve (AUC) tended to be high in the spatial presence-absence models at the highest level of resolution for species with large geographic ranges and small local populations. Prevalence affected training but not validation AUC. The key habitat predictors identified and the fish-habitat relationships evaluated through partial dependence plots corroborated most previous studies. The community-based SDM framework broadens our capability to model species distributions by innovatively removing the

  20. Using Historical Atlas Data to Develop High-Resolution Distribution Models of Freshwater Fishes.

    PubMed

    Huang, Jian; Frimpong, Emmanuel A

    2015-01-01

    Understanding the spatial pattern of species distributions is fundamental in biogeography, and conservation and resource management applications. Most species distribution models (SDMs) require or prefer species presence and absence data for adequate estimation of model parameters. However, observations with unreliable or unreported species absences dominate and limit the implementation of SDMs. Presence-only models generally yield less accurate predictions of species distribution, and make it difficult to incorporate spatial autocorrelation. The availability of large amounts of historical presence records for freshwater fishes of the United States provides an opportunity for deriving reliable absences from data reported as presence-only, when sampling was predominantly community-based. In this study, we used boosted regression trees (BRT), logistic regression, and MaxEnt models to assess the performance of a historical metacommunity database with inferred absences, for modeling fish distributions, investigating the effect of model choice and data properties thereby. With models of the distribution of 76 native, non-game fish species of varied traits and rarity attributes in four river basins across the United States, we show that model accuracy depends on data quality (e.g., sample size, location precision), species' rarity, statistical modeling technique, and consideration of spatial autocorrelation. The cross-validation area under the receiver-operating-characteristic curve (AUC) tended to be high in the spatial presence-absence models at the highest level of resolution for species with large geographic ranges and small local populations. Prevalence affected training but not validation AUC. The key habitat predictors identified and the fish-habitat relationships evaluated through partial dependence plots corroborated most previous studies. The community-based SDM framework broadens our capability to model species distributions by innovatively removing the

  1. Acute Toxicity and Bioaccumulation of Chloroform to Four Species of Freshwater Fish

    SciTech Connect

    ,

    1980-08-01

    Acute toxicity of chloroform to four species of freshwater fish was studied in flow-through 96-hr toxicity tests. Chloroform is toxic to fish in the tens of parts per million, a concentration well above that which would be expected to be produced under normal power plant chlorination conditions. Investigations of acute toxicity of chloroform and the bioaccumulation of chlorinated compounds in tissues of fish revealed differences in tolerance levels and tissue accumulations. Mean 96-hr LC{sub 50}s for chloroform were 18 ppm for rainbow trout and bluegill, 51 ppm for largemouth bass and 75 ppm for channel catfish. Mortalities of bluegill and largemouth bass occurred during the first 4 hr of exposure while rainbow trout and channel catfish showed initial tolerance and mortalities occurred during the latter half of the 96-hr exposure. Rainbow trout had the highest level of chloroform tissue accumulation, 7 {micro}g/g tissue, catfish the second highest, 4 {micro}g/g tissue, followed by bluegill and largemouth bass which each accumulated about 3 {micro}g/g tissue. Accumulation of chloroform was less than one order of magnitude above water concentrations for all species.

  2. Iridovirus disease in two ornamental tropical freshwater fishes: African lampeye and dwarf gourami.

    PubMed

    Sudthongkong, Chaiwud; Miyata, Masato; Miyazaki, Teruo

    2002-04-01

    Many species of ornamental freshwater fishes are imported into Japan from all over the world. We found African lampeye Aplocheilichthys normani and dwarf gourami Colisa lalia suffering from an iridovirus infection just after being imported by tropical fish wholesalers from Singapore. African lampeye were cultured on the Indonesian Island of Sumatra and dwarf gourami were cultured in Malaysia before export. Diseased fishes displayed distinct histopathological signs of iridovirus infection: systemic appearance of inclusion body-bearing cells, and necrosis of splenocytes and hematopoietic cells. Electron microscopy revealed viral particles (African lampeye:180 to 200 nm in edge to edge diameter; dwarf gourami: 140 to 150 nm in diameter) in an inclusion body within the cytoplasm of inclusion body-bearing cells as well as in the cytoplasm of necrotized cells. Experimental infection with an iridovirus isolate from African lampeye (ALIV) revealed pathogenicity of ALIV to African lampeye and pearl gourami Trichogaster leeri. Polymerase chain reaction (PCR) products from ALIV and an iridovirus isolate from dwarf gourami (DGIV) using iridovirus-specific primers were indistinguishable. The nucleotide sequence of PCR products derived from ALIV (696 base pairs) and DGIV (701 base pairs) had 95.3% identity. These results indicate that ALIV and DGIV have a single origin. PMID:12033703

  3. BIOAVAILABILITY OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN FROM MUNICIPAL INCINERATOR FLY ASH TO FRESHWATER FISH

    EPA Science Inventory

    The bioavailability of 2,3,7,8-TCDD from municipal incinerator fly ash to freshwater fish was determined. It was observed that carp exposed to fly ash containing all 22 TCDD isomers, or the solvent extract of the fly ash, retain only 2,3,7,8-TCDD. Exposures with fly ash appears t...

  4. Prevalence of Eustrongylides ignotus in mosquitofish (Gambusia holbrooki) in Florida: historical and regional comparisons.

    PubMed

    Frederick, P C; McGehee, S M; Spalding, M G

    1996-07-01

    We examined mosquitofish (Gambusia holbrooki) caught between January 1990 and December 1991 from 24 sites in northern Florida (USA), and preserved specimens collected from 32 sites throughout Florida between 1930 and 1978, for presence of the larval nematode Eustrongylides ignotus. We found 10 (42%) of the 24 recently-sampled sites in northern and central Florida had at least one larval nematode present in the fish; combining these data with results of previous work, 11 (15%) of 75 recently sampled sites throughout Florida had at least one nematode. By comparison, in the museum collections fish from only one (3%) of the 32 sites had the nematode, and none in northern Florida. PMID:8827688

  5. Development and characterization of 24 polymorphic microsatellite loci for the freshwater fish Ichthyoelephas longirostris (Characiformes: Prochilodontidae)

    PubMed Central

    Landínez-García, Ricardo M.

    2016-01-01

    The Neotropical freshwater fish Ichthyoelephas longirostris (Characiformes: prochilodontidae) is a short-distance migratory species endemic to Colombia. This study developed for the first time a set of 24 polymorphic microsatellite loci by using next-generation sequencing to explore the population genetics of this commercially exploited species. Nineteen of these loci were used to assess the genetic diversity and structure of 193 I. longirostris in three Colombian rivers of the Magdalena basin. Results showed that a single genetic stock circulates in the Cauca River, whereas other single different genetic stock is present in the rivers Samaná Norte and San Bartolomé-Magdalena. Additionally, I. longirostris was genetically different among and across rivers. This first insight about the population genetic structure of I. longirostris is crucial for monitoring the genetic diversity, the management and conservation of its populations, and complement the genetic studies in Prochilodontidae.

  6. Cladistics of the Lernaeidae (Cyclopoida), a major family of freshwater fish parasites

    NASA Astrophysics Data System (ADS)

    Ho, Ju-shey

    1998-06-01

    Currently about 110 species of lernaeid copepods are known from 332 species of freshwater fishes belonging to 161 genera in 41 families. Fourteen lernaeid genera are recognized in this study with two of them Lamproglena and Lernaea, containing the bulk of the species (81/113 or 71.7%). Two trees were obtained from a cladistic analysis with length of 14 steps, consistency index of 92 and a retention index of 97. The adopted phylogenetic hypothesis shows that the Lernaeidae can be divided into two subfamilies: Lernaeinae (including Areotrachelus, Dysphorus, Lernaea, Lernaeogiraffa, Opistholernaea, Pillainus, Taurocheros) and Lamprogleinae (including Afrolernaea, Catlaphilla, Indolernaea, Indopeniculus, Lamproglena, Lamproglenoides, Pseudolamproglena); while the Lernaeinae have wide geographic distribution, members of the Lamprogleninae are confined to Africa and Asia. Analysis of the area cladogram revealed that this pattern of uneven distribution has resulted from an explosive cladogenesis of the Lamprogleninae on the mobile `Indian Raft' in the Tertiary, before collision of this subcontinent with the Asian continent.

  7. Trematode diversity in freshwater fishes of the Globe I: 'Old World'.

    PubMed

    Scholz, Tomáš; Besprozvannykh, Vladimir V; Boutorina, Tamara E; Choudhury, Anindo; Cribb, Thomas H; Ermolenko, Alexey V; Faltýnková, Anna; Shedko, Marina B; Shimazu, Takeshi; Smit, Nico J

    2016-03-01

    In this paper, we review, continent by continent, the trematode fauna of freshwater fishes of the 'Old World', a vast area consisting of the Palaearctic, Ethiopian, Oriental and Australasian zoogeographical regions. Knowledge of this fauna is highly uneven and clearly incomplete for almost all regions, sometimes dramatically so. Although the biggest problem remains the completion of the 'first pass' of alpha taxonomy, there are in addition great problems relating to biogeography and elucidation of life-cycles. For the latter, molecular data, i.e. matching DNA sequences of larval stages and corresponding adults, may represent a powerful tool that should be used in future studies. Another challenging problem represents the existence of cryptic species and, in particular, considerable decrease of experts in taxonomy and life-cycles of trematodes. PMID:26898589

  8. Defining conservation priorities for freshwater fishes according to taxonomic, functional, and phylogenetic diversity

    USGS Publications Warehouse

    Strecker, Angela; Olden, Julian D.; Whittier, Joanna B.; Paukert, Craig P.

    2011-01-01

    To date, the predominant use of systematic conservation planning has been to evaluate and conserve areas of high terrestrial biodiversity. Although studies in freshwater ecosystems have received recent attention, research has rarely considered the potential trade-offs between protecting different dimensions of biodiversity and the ecological processes that maintain diversity. We provide the first systematic prioritization for freshwaters (focusing on the highly threatened and globally distinct fish fauna of the Lower Colorado River Basin, USA) simultaneously considering scenarios of: taxonomic, functional, and phylogenetic diversity; contemporary threats to biodiversity (including interactions with nonnative species); and future climate change and human population growth. There was 75% congruence between areas of highest conservation priority for different aspects of biodiversity, suggesting that conservation efforts can concurrently achieve strong complementarity among all types of diversity. However, sizable fractions of the landscape were incongruent across conservation priorities for different diversity scenarios, underscoring the importance of considering multiple dimensions of biodiversity and highlighting catchments that contribute disproportionately to taxonomic, functional, and phylogenetic diversity in the region. Regions of projected human population growth were not concordant with conservation priorities; however, higher human population abundance will likely have indirect effects on native biodiversity by increasing demand for water. This will come in direct conflict with projected reductions in precipitation and warmer temperatures, which have substantial overlap with regions of high contemporary diversity. Native and endemic fishes in arid ecosystems are critically endangered by both current and future threats, but our results highlight the use of systematic conservation planning for the optimal allocation of limited resources that incorporates

  9. Defining conservation priorities for freshwater fishes according to taxonomic, functional, and phylogenetic diversity

    USGS Publications Warehouse

    Strecker, A.L.; Olden, J.D.; Whittier, Joanna B.; Paukert, C.P.

    2011-01-01

    To date, the predominant use of systematic conservation planning has been to evaluate and conserve areas of high terrestrial biodiversity. Although studies in freshwater ecosystems have received recent attention, research has rarely considered the potential tradeoffs between protecting different dimensions of biodiversity and the ecological processes that maintain diversity. We provide the first systematic prioritization for freshwaters (focusing on the highly threatened and globally distinct fish fauna of the Lower Colorado River Basin, USA) simultaneously considering scenarios of: taxonomic, functional, and phylogenetic diversity;contemporary threats to biodiversity (including interactions with nonnative species);and future climate change and human population growth. There was 75% congruence between areas of highest conservation priority for different aspects of biodiversity, suggesting that conservation efforts can concurrently achieve strong complementarity among all types of diversity. However, sizable fractions of the landscape were incongruent across conservation priorities for different diversity scenarios, underscoring the importance of considering multiple dimensions of biodiversity and highlighting catchments that contribute disproportionately to taxonomic, functional, and phylogenetic diversity in the region. Regions of projected human population growth were not concordant with conservation priorities;however, higher human population abundance will likely have indirect effects on native biodiversity by increasing demand for water. This will come in direct conflict with projected reductions in precipitation and warmer temperatures, which have substantial overlap with regions of high contemporary diversity. Native and endemic fishes in arid ecosystems are critically endangered by both current and future threats, but our results highlight the use of systematic conservation planning for the optimal allocation of limited resources that incorporates multiple

  10. Taxonomic Distinctness and Richness of Helminth Parasite Assemblages of Freshwater Fishes in Mexican Hydrological Basins

    PubMed Central

    Quiroz-Martínez, Benjamín; Salgado-Maldonado, Guillermo

    2013-01-01

    In this paper, we analyse the distributional patterns of adult helminth parasites of freshwater fishes with respect to the main hydrological basins of Mexico. We use the taxonomic distinctness and the variation in taxonomic distinctness to explore patterns of parasite diversity and how these patterns change between zoogeographical regions. We address questions about the factors that determine the variation of observed diversity of helminths between basins. We also investigate patterns of richness, taxonomic distinctness and distance decay of similarity amongst basins. Our analyses suggest that the evolution of the fauna of helminth parasites in Mexico is mostly dominated by independent host colonization events and that intra - host speciation could be a minor factor explaining the origin of this diversity. This paper points out a clear separation between the helminth faunas of northern - nearctic and southern - neotropical components in Mexican continental waters, suggesting the availability of two distinct taxonomic pools of parasites in Mexican drainage basins. Data identifies Mexican drainage basins as unities inhabited by freshwater fishes, hosting a mixture of neotropical and nearctic species, in addition, data confirms neotropical and neartic basins/helminth faunas. The neotropical basins of Mexico are host to a richest and more diversified helminth fauna, including more families, genera and species, compared to the less rich and less diverse helminth fauna in the nearctic basins. The present analysis confirms distance - decay as one of the important factors contributing to the patterns of diversity observed. The hypothesis that helminth diversity could be explained by the ichthyological diversity of the basin received no support from present analysis. PMID:24086342

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

    PubMed

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

    2015-10-01

    Genetic diversity is an essential aspect of species viability, and assessments of neutral genetic diversity are regularly implemented in captive breeding and conservation programs. Despite their importance, information from adaptive markers is rarely included in such programs. A promising marker of significance in fitness and adaptive potential is the major histocompatibility complex (MHC), a key component of the adaptive immune system. Populations of Australian freshwater fishes are generally declining in numbers due to human impacts and the introduction of exotic species, a scenario of particular concern for members of the family Percichthyidae, several of which are listed as nationally vulnerable or endangered, and hence subject to management plans, captive breeding, and restoration plans. We used a next-generation sequencing approach to characterize the MHC IIB locus and provide a conservative description of its levels of diversity in four endangered percichthyids: Gadopsis marmoratus, Macquaria australasica, Nannoperca australis, and Nannoperca obscura. Evidence is presented for a duplicated MHC IIB locus, positively selected sites and recombination of MHC alleles. Relatively moderate levels of diversity were detected in the four species, as well as in different ecotypes within each species. Phylogenetic analyses revealed genus specific clustering of alleles and no allele sharing among species. There were also no shared alleles observed between two ecotypes within G. marmoratus and within M. australasica, which might be indicative of ecologically-driven divergence and/or long divergence times. This represents the first characterization and assessment of MHC diversity for Percichthyidae, and also for Australian freshwater fishes in general, providing key genetic resources for a vertebrate group of increasing conservation concern. PMID:26093210

  12. Conflict between background matching and social signalling in a colour-changing freshwater fish.

    PubMed

    Kelley, Jennifer L; Rodgers, Gwendolen M; Morrell, Lesley J

    2016-06-01

    The ability to change coloration allows animals to modify their patterning to suit a specific function. Many freshwater fishes, for example, can appear cryptic by altering the dispersion of melanin pigment in the skin to match the visual background. However, melanin-based pigments are also used to signal dominance among competing males; thus colour change for background matching may conflict with colour change for social status signalling. We used a colour-changing freshwater fish to investigate whether colour change for background matching influenced aggressive interactions between rival males. Subordinate males that had recently darkened their skin for background matching received heightened aggression from dominant males, relative to males whose coloration had not changed. We then determined whether the social status of a rival male, the focal male's previous social status, and his previous skin coloration, affected a male's ability to change colour for background matching. Social status influenced skin darkening in the first social encounter, with dominant males darkening more than subordinate males, but there was no effect of social status on colour change in the second social encounter. We also found that the extent of skin colour change (by both dominant and subordinate males) was dependent on previous skin coloration, with dark males displaying a smaller change in coloration than pale males. Our findings suggest that skin darkening for background matching imposes a significant social cost on subordinate males in terms of increased aggression. We also suggest that the use of melanin-based signals during social encounters can impede subsequent changes in skin coloration for other functions, such as skin darkening for background matching. PMID:27429764

  13. Conflict between background matching and social signalling in a colour-changing freshwater fish

    PubMed Central

    Rodgers, Gwendolen M.; Morrell, Lesley J.

    2016-01-01

    The ability to change coloration allows animals to modify their patterning to suit a specific function. Many freshwater fishes, for example, can appear cryptic by altering the dispersion of melanin pigment in the skin to match the visual background. However, melanin-based pigments are also used to signal dominance among competing males; thus colour change for background matching may conflict with colour change for social status signalling. We used a colour-changing freshwater fish to investigate whether colour change for background matching influenced aggressive interactions between rival males. Subordinate males that had recently darkened their skin for background matching received heightened aggression from dominant males, relative to males whose coloration had not changed. We then determined whether the social status of a rival male, the focal male's previous social status, and his previous skin coloration, affected a male's ability to change colour for background matching. Social status influenced skin darkening in the first social encounter, with dominant males darkening more than subordinate males, but there was no effect of social status on colour change in the second social encounter. We also found that the extent of skin colour change (by both dominant and subordinate males) was dependent on previous skin coloration, with dark males displaying a smaller change in coloration than pale males. Our findings suggest that skin darkening for background matching imposes a significant social cost on subordinate males in terms of increased aggression. We also suggest that the use of melanin-based signals during social encounters can impede subsequent changes in skin coloration for other functions, such as skin darkening for background matching. PMID:27429764

  14. Can Species Distribution Models Aid Bioassessment when Reference Sites are Lacking? Tests Based on Freshwater Fishes

    NASA Astrophysics Data System (ADS)

    Labay, Ben J.; Hendrickson, Dean A.; Cohen, Adam E.; Bonner, Timothy H.; King, Ryan S.; Kleinsasser, Leroy J.; Linam, Gordon W.; Winemiller, Kirk O.

    2015-10-01

    Recent literature reviews of bioassessment methods raise questions about use of least-impacted reference sites to characterize natural conditions that no longer exist within contemporary landscapes. We explore an alternate approach for bioassessment that uses species site occupancy data from museum archives as input for species distribution models (SDMs) stacked to predict species assemblages of freshwater fishes in Texas. When data for estimating reference conditions are lacking, deviation between richness of contemporary versus modeled species assemblages could provide a means to infer relative biological integrity at appropriate spatial scales. We constructed SDMs for 100 freshwater fish species to compare predicted species assemblages to data on contemporary assemblages acquired by four independent surveys that sampled 269 sites. We then compared site-specific observed/predicted ratios of the number of species at sites to scores from a multimetric index of biotic integrity (IBI). Predicted numbers of species were moderately to strongly correlated with the numbers observed by the four surveys. We found significant, though weak, relationships between observed/predicted ratios and IBI scores. SDM-based assessments identified patterns of local assemblage change that were congruent with IBI inferences; however, modeling artifacts that likely contributed to over-prediction of species presence may restrict the stand-alone use of SDM-derived patterns for bioassessment and therefore warrant examination. Our results suggest that when extensive standardized survey data that include reference sites are lacking, as is commonly the case, SDMs derived from generally much more readily available species site occupancy data could be used to provide a complementary tool for bioassessment.

  15. Toxicity, sublethal effects, and potential modes of action of select fungicides on freshwater fish and invertebrates

    USGS Publications Warehouse

    Elskus, Adria A.

    2012-01-01

    Despite decades of agricultural and urban use of fungicides and widespread detection of these pesticides in surface waters, relatively few data are available on the effects of fungicides on fish and invertebrates in the aquatic environment. Nine fungicides are reviewed in this report: azoxystrobin, boscalid, chlorothalonil, fludioxonil, myclobutanil, fenarimol, pyraclostrobin, pyrimethanil, and zoxamide. These fungicides were identified as emerging chemicals of concern because of their high or increasing global use rates, detection frequency in surface waters, or likely persistence in the environment. A review of the literature revealed significant sublethal effects of fungicides on fish, aquatic invertebrates, and ecosystems, including zooplankton and fish reproduction, fish immune function, zooplankton community composition, metabolic enzymes, and ecosystem processes, such as leaf decomposition in streams, among other biological effects. Some of these effects can occur at fungicide concentrations well below single-species acute lethality values (48- or 96-hour concentration that effects a response in 50 percent of the organisms, that is, effective concentration killing 50 percent of the organisms in 48 or 96 hours) and chronic sublethal values (for example, 21-day no observed adverse effects concentration), indicating that single-species toxicity values may dramatically underestimate the toxic potency of some fungicides. Fungicide modes of toxic action in fungi can sometimes reflect the biochemical and (or) physiological effects of fungicides observed in vertebrates and invertebrates; however, far more studies are needed to explore the potential to predict effects in nontarget organisms based on specific fungicide modes of toxic action. Fungicides can also have additive and (or) synergistic effects when used with other fungicides and insecticides, highlighting the need to study pesticide mixtures that occur in surface waters. For fungicides that partition to

  16. Radiological impact of the nuclear power plant accident on freshwater fish in Fukushima: An overview of monitoring results.

    PubMed

    Wada, Toshihiro; Tomiya, Atsushi; Enomoto, Masahiro; Sato, Toshiyuki; Morishita, Daigo; Izumi, Shigehiko; Niizeki, Kouji; Suzuki, Shunji; Morita, Takami; Kawata, Gyo

    2016-01-01

    Radionuclide ((131)I, (134)Cs, and (137)Cs) concentrations of monitored freshwater fish species collected from different habitats (rivers, lakes, and culture ponds) in Fukushima Prefecture during March 2011-December 2014 (total 16 species, n = 2692) were analyzed to present a detailed description of radionuclide contamination after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, and to elucidate species-specific spatiotemporal declining trends of (137)Cs concentration for their respective habitats. Low concentrations of (131)I (≤24 Bq kg(-1)-wet) were detected from only 11 samples collected during March-June 2011, demonstrating that (131)I transferred to freshwater fish were not intense. In river and lake fishes, a more gradual decrease and higher radiocesium ((134)Cs, (137)Cs) concentrations were observed than in culture pond fishes, which strongly implied that radiocesium in freshwater fish species was mainly bioaccumulated through the food web in the wild. During 2011-2014, percentages above the Japanese regulatory limit of 100 Bq kg(-1)-wet for radiocesium in river and lake fish (14.0% and 39.6%, respectively) were higher than in monitored marine fish (9.9%), indicating longer-term contamination of freshwater fish species, especially in lakes. Higher radiocesium concentrations (maximum 18.7 kBq kg(-1)-wet in Oncorhynchus masou) were found in the northwestern areas from the FDNPP with higher deposition. However, radiocesium contamination levels were regarded as 1-2 orders of magnitude less than those after the Chernobyl accident. Lagged increase of (137)Cs concentration and longer ecological half-lives (Teco: 1.2-2.6 y in the central part of Fukushima Prefecture) were observed in carnivorous salmonids (O. masou, Salvelinus leucomaenis), whereas a rapid increase and decrease of (137)Cs concentration and shorter Teco (0.99 and 0.69 y) were found in herbivorous and planktivorous osmerids (Plecoglossus altivelis, Hypomesus nipponensis) with

  17. Transcriptome profiling of two Iberian freshwater fish exposed to thermal stress.

    PubMed

    Jesus, Tiago Filipe; Grosso, Ana Rita; Almeida-Val, Vera Maria Fonseca; Coelho, Maria Manuela

    2016-01-01

    The congeneric freshwater fish Squalius carolitertii and S. torgalensis inhabit different Iberian regions with distinct climates; Atlantic in the North and Mediterranean in the South, respectively. While northern regions present mild temperatures, fish in southern regions often experience harsh temperatures and droughts. Previous work with two hsp70 genes suggested that S. torgalensis is better adapted to harsher thermal conditions than S. carolitertii as a result of the different environmental conditions. We present a transcriptomic characterisation of these species' thermal stress responses. Through differential gene expression analysis of the recently available transcriptomes of these two endemic fish species, comprising 12 RNA-seq libraries from three tissues (skeletal muscle, liver and fins) of fish exposed to control (18 °C) and test (30 °C) conditions, we intend to lay the foundations for further studies on the effects of temperature given predicted climate changes. Results showed that S. carolitertii had more upregulated genes, many of which are involved in transcription regulation, whereas S. torgalensis had more downregulated genes, particularly those responsible for cell division and growth. However, both species displayed increased gene expression of many hsps genes, suggesting that they are able to deal with protein damage caused by heat, though with a greater response in S. torgalensis. Together, our results suggest that S. torgalensis may have an energy saving strategy during short periods of high temperatures, re-allocating resources from growth to stress response mechanisms. In contrast, S. carolitertii regulates its metabolism by increasing the expression of genes involved in transcription and promoting the stress response, probably to maintain homoeostasis. Additionally, we indicate a set of potential target genes for further studies that may be particularly suited to monitoring the responses of Cyprinidae to changing temperatures, particularly

  18. An eDNA Assay to Monitor a Globally Invasive Fish Species from Flowing Freshwater

    PubMed Central

    Adrian-Kalchhauser, Irene; Burkhardt-Holm, Patricia

    2016-01-01

    Ponto-Caspian gobies are a flock of five invasive fish species that have colonized freshwaters and brackish waters in Europe and North America. One of them, the round goby Neogobius melanostomus, figures among the 100 worst invaders in Europe. Current methods to detect the presence of Ponto-Caspian gobies involve catching or sighting the fish. These approaches are labor intense and not very sensitive. Consequently, populations are usually detected only when they have reached high densities and when management or containment efforts are futile. To improve monitoring, we developed an assay based on the detection of DNA traces (environmental DNA, or eDNA) of Ponto-Caspian gobies in river water. The assay specifically detects invasive goby DNA and does not react to any native fish species. We apply the assay to environmental samples and demonstrate that parameters such as sampling depth, sampling location, extraction protocol, PCR protocol and PCR inhibition greatly impact detection. We further successfully outline the invasion front of Ponto-Caspian gobies in a large river, the High Rhine in Switzerland, and thus demonstrate the applicability of the assay to lotic environments. The eDNA assay requires less time, equipment, manpower, skills, and financial resources than the conventional monitoring methods such as electrofishing, angling or diving. Samples can be taken by untrained individuals, and the assay can be performed by any molecular biologist on a conventional PCR machine. Therefore, this assay enables environment managers to map invaded areas independently of fishermen’s’ reports and fish community monitorings. PMID:26814998

  19. Gasoline effects on biotransformation and antioxidant defenses of the freshwater fish Prochilodus lineatus.

    PubMed

    Simonato, Juliana D; Fernandes, Marisa Narciso; Martinez, Cláudia B R

    2011-08-01

    Biochemical biomarkers in the Neotropical freshwater fish Prochilodus lineatus were evaluated following acute exposures to the water-soluble fraction of gasoline (WSFG). Fish were exposed to the WSFG diluted to 5% in water (WSFG group) or only to water (Control group) for 6, 24 and 96 h and the gills and liver were removed for the biochemical analyses. Fish exposed to WSFG for 24 and 96 h showed significant increase in the activity of 7-ethoxyresorufin-O-deethylase (EROD) and glutathione-S-transferase (GST) both in liver and gills, pointing toward phase I and phase II biotransformation of the compounds present in the WSFG. The results also indicated the activation of antioxidant defenses in both the liver and gills after fish exposure to WSFG. The liver showed activation of catalase (CAT) and glutathione peroxidase (GPx) after 96 h exposure. An increase in hepatic content of reduced glutathione (GSH) together with decreased glutathione reductase (GR) activity was observed after 24 and 96 h of exposure to WSFG. In the gills, only catalase (CAT) activity augmented after 6 and 24 h of exposure and GSH content increased after 24 h of WSFG exposure. However, in both the organs, activation of the antioxidant defenses was not enough to prevent oxidative damage since they showed lipid peroxidation (LPO) at one of the experimental times: the liver after 6 h and the gills only after 96 h of exposure to WSFG. This may indicate better adaptation of the liver to longer exposures, starting from 24 h. As the gills are the first organ to be exposed to xenobiotics, the antioxidant defenses were triggered immediately upon exposure to WSFG and were able to prevent the occurrence of LPO during the initial times. PMID:21560013

  20. Cardiorespiratory toxicity of environmentally relevant zinc oxide nanoparticles in the freshwater fish Catostomus commersonii.

    PubMed

    Bessemer, Robin Anne; Butler, Kathryn Marie Alison; Tunnah, Louise; Callaghan, Neal Ingraham; Rundle, Amanda; Currie, Suzanne; Dieni, Christopher Anthony; MacCormack, Tyson James

    2015-01-01

    The inhalation of zinc oxide engineered nanomaterials (ENMs) has been linked to cardiorespiratory dysfunction in mammalian models but the effects of aquatic ENM exposure on fish have not been fully investigated. Nano-zinc oxide (nZnO) is widely used in consumer products such as sunscreens and can make its way into aquatic ecosystems from domestic and commercial wastewater. This study examined the impact of an environmentally relevant nZnO formulation on cardiorespiratory function and energy metabolism in the white sucker (Catostomus commersonii), a freshwater teleost fish. Evidence of oxidative and cellular stress was present in gill tissue, including increases in malondialdehyde levels, heat shock protein (HSP) expression, and caspase 3/7 activity. Gill Na(+)/K(+)-ATPase activity was also higher by approximately three-fold in nZnO-treated fish, likely in response to increased epithelial permeability or structural remodeling. Despite evidence of toxicity in gill, plasma cortisol and lactate levels did not change in animals exposed to 1.0 mg L(-1) nZnO. White suckers also exhibited a 35% decrease in heart rate during nZnO exposure, with no significant changes in resting oxygen consumption or tissue energy stores. Our results suggest that tissue damage or cellular stress resulting from nZnO exposure activates gill neuroepithelial cells, triggering a whole-animal hypoxic response. An increase in parasympathetic nervous signaling will decrease heart rate and may reduce energy demand, even in the face of an environmental toxicant. We have shown that acute exposure to nZnO is toxic to white suckers and that ENMs have the potential to negatively impact cardiorespiratory function in adult fish. PMID:25427894

  1. Prevalence and antimicrobial resistance of Salmonella spp. in raw retail frozen imported freshwater fish to Eastern Province of Saudi Arabia

    PubMed Central

    Elhadi, Nasreldin

    2014-01-01

    Objective To determine the proportion of imported frozen fish contaminated with Salmonella among retail food stores and supermarkets in the Eastern Province of Saudi Arabia. Methods A total of 223 frozen freshwater fish purchased from different supermarkets and grocery stores were analyzed for the presence of foodborne pathogen Salmonella. The isolation of Salmonella was determined and confirmed by using the methods of US Food and Drug Administration's Bacteriological Analytical Manual, CHROMagar Salmonella plus, biochemical tests and API 20E strips. Antimicrobial susceptibilities of Salmonella isolates were determined by the disk diffusion method on Muller-Hinton agar, as described by Kirby-Bauer, in accordance with the guidelines of the Clinical and Laboratory Standards Institute. Results Out of the total 223 fish samples (20 of catfish, 18 of carfu, 20 of mirgal, 25 of milkfish, 35 of mackerel, 75 of tilapia, and 30 of rohu), 89 (39.9%) were tested positive for Salmonella. The prevalence of positive samples were reported for the freshwater fish of pangas (60.0%, n=12), carfu (27.7%, n=5), mirgal (35.0%, n=7), milkfish (52.0%, n=13), mackerel (31.4 %, n=11), tilapia imported from Thailand (64.0%, n=16), tilapia imported from India (28.0%, n=14), rohu imported from Thailand (26.6%, n=4) and rohu imported from Myanmar (46.6%, n=7). A total of 140 isolates of Salmonella spp. were yielded from at least seven different types of frozen freshwater fish imported from 5 different countries and were tested for their susceptibility to 16 selected antimicrobial agents. The highest antibiotic resistance was observed to tetracycline (90.71%) followed by ampicillin (70%) and amoxicillin-clavulanic acid (45%). Conclusions The obtained results of this study shows that these raw retail imported frozen freshwater fish are contaminated with potentially pathogenic Salmonella spp. And the study recommend and suggest that there is a need for adequate consumer measures. PMID:25182443

  2. Population genetic structure of the acanthocephalan Acanthosentis cheni in anadromous, freshwater, and landlocked stocks of its fish host, Coilia nasus.

    PubMed

    Song, Rui; Li, Wen X; Wu, Shan G; Zou, Hong; Wang, Gui T

    2014-04-01

    The acanthocephalan Acanthosentis cheni was found in anadromous, freshwater, and landlocked stocks of its fish host, Coilia nasus. To examine the genetic variations of the acanthocephalan among the 3 populations with the adaptation of the host to the freshwater, the genetic structure of the helminth was investigated in anadromous (Zhoushan and Chongming islands, and Anqing), freshwater (Anqing, Ezhou, and Poyang Lake), and landlocked (Tian'ezhou Reserve) populations by sequencing intergenic transcribed spacers (ITS) of the ribosomal RNA coding genes. Low Fst values and high gene flow were found among the 7 populations (Fst = 0.0135, P = 0.2723; Nm = 36.48) and the 3 ecotypes of Acanthosentis cheni (Fst = 0.0178, P = 0.1044; Nm = 27.67). On the other hand, significant genetic differentiation of the C. nasus host populations was detected between the upstream and downstream areas of Xiaogu Mountain (Fst = 0.1961, P = 0.0030; Nm = 2.05), which is the farthest location of spawning migration for C. nasus . However, the migration break of the fish host appeared not to cause significant genetic differentiation of A. cheni populations between the upper and lower reaches of Xiaogu Mountain. Other factors might promote genetic exchange of A. cheni populations such as dispersal of the intermediate host by flooding or other fish species serving as the definitive or paratenic hosts. In Anqing, nucleotide diversity of the acanthocephalan was highest in the freshwater population (0.0038) and lower in the anadromous population (0.0026). This suggested that new mutations may have occurred in the freshwater A. cheni population in Anqing when adapting to a freshwater environment. PMID:24224788

  3. Prevalence and intensity of fish-borne zoonotic trematodes in cultured freshwater fish from rural and urban areas of northern Vietnam.

    PubMed

    Van De, Nguyen; Le, Thanh Hoa; Murrell, K D

    2012-10-01

    Consumption of raw freshwater fish produced in both rural farm and urban wastewater ponds is a common practice in Vietnam. The present study assessed the risk of fish-borne zoonotic trematode (FZT) infection from fish raised in both these aquaculture systems in northern Vietnam. The diversity, prevalence, and infection intensity of FZT metacercariae in 1,500 freshwater fish collected from 6 sites located in rural and urban areas in northern Vietnam were investigated. The specific diagnosis of species was made by morphologic methods. The overall FZT prevalence in fish from both urban wastewater ponds and rural farm ponds was 11.2%. In wastewater ponds, the overall prevalence was 5.1%, ranging from 2.0% in tilapia to 7.3% in common and grass carp. In fish from farm ponds, the prevalence was 17.3%, and ranged from 6.7% in mud carp to 26.7% in common carp. The mean intensity of FZT infection was also higher in fish from farm ponds than that in fish from wastewater ponds (6.0% and 8.4%, respectively). The FZT species recovered from infected fish included both liver (Clonorchis sinensis) and intestinal flukes (Haplorchis taichui, Haplorchis pumilio, and Centrocestus formosanus). The prevalence of FZT in fish raised in these common farm systems represents a significant public health risk for a population with a strong cultural preference for consuming raw or inadequately prepared fish. These research results should encourage the public health and agriculture sectors to conduct the risk factor research required to develop control programs for FZT. PMID:22471793

  4. Phylogenetic relationships and evolutionary history of the Mesoamerican endemic freshwater fish family Profundulidae (Cyprinodontiformes: Actinopterygii).

    PubMed

    Morcillo, Felipe; Ornelas-García, Claudia Patricia; Alcaraz, Lourdes; Matamoros, Wilfredo A; Doadrio, Ignacio

    2016-01-01

    Freshwater fishes of Profundulidae, which until now was composed of two subgenera, represent one of the few extant fish families endemic to Mesoamerica. In this study we investigated the phylogenetic relationships and evolutionary history of the eight recognized extant species (from 37 populations) of Profundulidae using three mitochondrial and one nuclear gene markers (∼2.9 Kbp). We applied a Bayesian species delimitation method as a first approach to resolving speciation patterns within Profundulidae considering two different scenarios, eight-species and twelve-species models, obtained in a previous phylogenetic analysis. Based on our results, each of the two subgenera was resolved as monophyletic, with a remarkable molecular divergence of 24.5% for mtDNA and 7.8% for nDNA uncorrected p distances, and thus we propose that they correspond to separate genera. Moreover, we propose a conservative taxonomic hypothesis with five species within Profundulus and three within Tlaloc, although both eight-species and twelve-species models were highly supported by the bayesian species delimitation analysis, providing additional evidence of higher taxonomic diversity than currently recognized in this family. According to our divergence time estimates, the family originated during the Upper Oligocene 26 Mya, and Profundulus and Tlaloc diverged in the Upper Oligocene or Lower Miocene about 20 Mya. PMID:26364972

  5. Mercury concentrations of a resident freshwater forage fish at Adak Island, Aleutian Archipelago, Alaska.

    PubMed

    Kenney, Leah A; von Hippel, Frank A; Willacker, James J; O'Hara, Todd M

    2012-11-01

    The Aleutian Archipelago is an isolated arc of over 300 volcanic islands stretching 1,600 km across the interface of the Bering Sea and North Pacific Ocean. Although remote, some Aleutian Islands were heavily impacted by military activities from World War II until recently and were exposed to anthropogenic contaminants, including mercury (Hg). Mercury is also delivered to these islands via global atmospheric transport, prevailing ocean currents, and biotransport by migratory species. Mercury contamination of freshwater ecosystems is poorly understood in this region. Total Hg (THg) concentrations were measured in threespine stickleback fish (Gasterosteus aculeatus) collected from eight lakes at Adak Island, an island in the center of the archipelago with a long military history. Mean THg concentrations for fish whole-body homogenates for all lakes ranged from 0.314 to 0.560 mg/kg dry weight. Stickleback collected from seabird-associated lakes had significantly higher concentrations of THg compared to non-seabird lakes, including all military lakes. The δ(13)C stable isotope ratios of stickleback collected from seabird lakes suggest an input of marine-derived nutrients and/or marine-derived Hg. PMID:22912068

  6. MERCURY CONCENTRATIONS OF A RESIDENT FRESHWATER FORAGE FISH AT ADAK ISLAND, ALEUTIAN ARCHIPELAGO, ALASKA

    PubMed Central

    Kenney, Leah A.; von Hippel, Frank A.; Willacker, James J.; O’Hara, Todd M.

    2015-01-01

    The Aleutian Archipelago is an isolated arc of over 300 volcanic islands stretching 1,600 km across the interface of the Bering Sea and North Pacific Ocean. Although remote, some Aleutian Islands were heavily impacted by military activities from World War II until recently and were exposed to anthropogenic contaminants, including mercury (Hg). Mercury is also delivered to these islands via global atmospheric transport, prevailing ocean currents, and biotransport by migratory species. Mercury contamination of freshwater ecosystems is poorly understood in this region. Total Hg (THg) concentrations were measured in threespine stickleback fish (Gasterosteus aculeatus) collected from eight lakes at Adak Island, an island in the center of the archipelago with a long military history. Mean THg concentrations for fish whole-body homogenates for all lakes ranged from 0.314 to 0.560 mg/kg dry weight. Stickleback collected from seabird-associated lakes had significantly higher concentrations of THg compared to non-seabird lakes, including all military lakes. The δ13C stable isotope ratios of stickleback collected from seabird lakes suggest an input of marine-derived nutrients and/or marine-derived Hg. PMID:22912068

  7. Effects of degraded optical conditions on behavioural responses to alarm cues in a freshwater fish.

    PubMed

    Ranåker, Lynn; Nilsson, P Anders; Brönmark, Christer

    2012-01-01

    Prey organisms often use multiple sensory cues to gain reliable information about imminent predation threat. In this study we test if a freshwater fish increases the reliance on supplementary cues when the reliability of the primary cue is reduced. Fish commonly use vision to evaluate predation threat, but may also use chemical cues from predators or injured conspecifics. Environmental changes, such as increasing turbidity or water colour, may compromise the use of vision through changes in the optical properties of water. In an experiment we tested if changes in optical conditions have any effects on how crucian carp respond to chemical predator cues. In turbidity treatments we added either clay or algae, and in a brown water colour treatment we added water with a high humic content. We found that carp reduced activity in response to predator cues, but only in the turbidity treatments (clay, algae), whereas the response in the brown water treatment was intermediate, and not significantly different from, clear and turbid water treatments. The increased reliance on chemical cues indicates that crucian carp can compensate for the reduced information content from vision in waters where optical conditions are degraded. The lower effect in brown water may be due to the reduction in light intensity, changes in the spectral composition (reduction of UV light) or to a change in chemical properties of the cue in humic waters. PMID:22745663

  8. Validating methods for measuring delta18O and delta13C in otoliths from freshwater fish.

    PubMed

    Guiguer, K R R A; Drimmie, R; Power, M

    2003-01-01

    The ability of the phosphoric acid digestion technique to extract carbon dioxide from biogenic carbonates and reliably reproduce delta(18)O and delta(13)C signatures from standard reference materials (NBS-18, NBS-19) was tested and shown to produce accurate, unbiased measurements of non-biologic materials. The effects of roasting preparation methods commonly reported when analyzing biogenic carbonates were also tested in a series of experiments using reference standards and otoliths obtained from aquacultured Arctic charr and rainbow trout. Roasting had no effect on the isotope measurement of reference standards. No significant differences between mean oxygen isotope signatures from paired experiments with roasted and non-roasted fish otoliths were found. However, otolith oxygen isotope measurements were significantly enriched in comparison to rearing water-based measurements for both species. Agreement between expected isotopic equilibrium and measured otolith delta(18)O values varied as a function of roasting temperature and between species. Criteria for the selection of appropriate roasting temperatures are suggested and favour 350 degrees C in freshwater fish where unbiased estimates of average rearing water temperatures and known differences in rearing temperatures were obtained. Carbon isotopic disequilibria were observed for both species. A mixing model analysis established differences in the percentage of metabolically derived carbon in studied otoliths, with Arctic charr deriving a greater proportion of otolith delta(13)C from metabolism as a result of higher metabolic rates. PMID:12590395

  9. Shape up or ship out: migratory behaviour predicts morphology across spatial scale in a freshwater fish.

    PubMed

    Chapman, Ben B; Hulthén, Kaj; Brönmark, Christer; Nilsson, P Anders; Skov, Christian; Hansson, Lars-Anders; Brodersen, Jakob

    2015-09-01

    1. Migration is a widespread phenomenon, with powerful ecological and evolutionary consequences. Morphological adaptations to reduce the energetic costs associated with migratory transport are commonly documented for migratory species. However, few studies have investigated whether variation in body morphology can be explained by variation in migratory strategy within a species. 2. We address this question in roach Rutilus rutilus, a partially migratory freshwater fish that migrates from lakes into streams during winter. We both compare body shape between populations that differ in migratory opportunity (open vs. closed lakes), and between individuals from a single population that vary in migratory propensity (migrants and residents from a partially migratory population). Following hydrodynamic theory, we posit that migrants should have a more shallow body depth, to reduce the costs associated with migrating into streams with higher flow conditions than the lakes the residents occupy all year round. 3. We find evidence both across and within populations to support our prediction, with individuals from open lakes and migrants from the partially migratory population having a more slender, shallow-bodied morphology than fish from closed lakes and all-year residents. 4. Our data suggest that a shallow body morphology is beneficial to migratory individuals and our study is one of the first to link migratory strategy and intraspecific variation in body shape. PMID:25823702

  10. Cerium oxide nanoparticles exhibit minimal cardiac and cytotoxicity in the freshwater fish Catostomus commersonii.

    PubMed

    Rundle, Amanda; Robertson, Anne B; Blay, Alexandra M; Butler, Kathryn M A; Callaghan, Neal I; Dieni, Christopher A; MacCormack, Tyson J

    2016-01-01

    Metal oxide nanomaterials can cause oxidative, cardiorespiratory, and osmoregulatory stress in freshwater fish. In contrast, cerium oxide nanoparticles (nCeO2) can have antioxidant effects but their aquatic toxicity has not been fully characterized. Heart rate and heart rate variability were followed in white sucker (Catostomus commersonii) acutely exposed to 1.0 mg L(-1) nCeO2 for 25 h. Malondialdehyde (MDA) was measured to assess oxidative tissue damage, and plasma cortisol, glucose, lactate, and osmolality were assessed as indicators of physiological and osmoregulatory stress. There was no MDA accumulation in gill or heart of fish exposed to nCeO2 and heart function was unchanged over the 25 h treatment. Plasma cortisol increased 6-fold but there was no change in plasma glucose or lactate. Cellular osmoregulatory toxicity was studied using an isolated red blood cell (RBC) model. In vitro exposure to 1.0 mg L(-1) nCeO2 for 1h had no effect on cell morphological parameters and did not sensitize RBCs to hemolysis under hypotonic stress. Overall, there were no indications of oxidative, cardiorespiratory, or osmoregulatory stress following acute exposure to nCeO2. Elevated plasma cortisol levels suggest that nCeO2 may exert mild toxicity to tissues outside of the cardiorespiratory system. PMID:26743956

  11. Comparing distribution models for small samples of overdispersed counts of freshwater fish

    NASA Astrophysics Data System (ADS)

    Vaudor, Lise; Lamouroux, Nicolas; Olivier, Jean-Michel

    2011-05-01

    The study of species abundance often relies on repeated abundance counts whose number is limited by logistic or financial constraints. The distribution of abundance counts is generally right-skewed (i.e. with many zeros and few high values) and needs to be modelled for statistical inference. We used an extensive dataset involving about 100,000 fish individuals of 12 freshwater fish species collected in electrofishing points (7 m 2) during 350 field surveys made in 25 stream sites, in order to compare the performance and the generality of four distribution models of counts (Poisson, negative binomial and their zero-inflated counterparts). The negative binomial distribution was the best model (Bayesian Information Criterion) for 58% of the samples (species-survey combinations) and was suitable for a variety of life histories, habitat, and sample characteristics. The performance of the models was closely related to samples' statistics such as total abundance and variance. Finally, we illustrated the consequences of a distribution assumption by calculating confidence intervals around the mean abundance, either based on the most suitable distribution assumption or on an asymptotical, distribution-free (Student's) method. Student's method generally corresponded to narrower confidence intervals, especially when there were few (≤3) non-null counts in the samples.

  12. Ranking freshwater fish farms for the risk of pathogen introduction and spread.

    PubMed

    Oidtmann, B C; Crane, C N; Thrush, M A; Hill, B J; Peeler, E J

    2011-12-15

    A semi-quantitative model is presented to rank freshwater rainbow trout farms within a country or region with regards to the risk of becoming infected and spreading a specified pathogen. The model was developed to support a risk-based surveillance scheme for notifiable salmonid pathogens. Routes of pathogen introduction and spread were identified through a process of expert consultation in a series of workshops. The routes were combined into themes (e.g. exposure via water, mechanical transmission). Themes were weighted based on expert opinion. Risk factors for each route were scored and combined into a theme score which was adjusted by the weight. The number of sources and consignments were used to assess introduction via live fish movements onto the farm. Biosecurity measures were scored to assess introduction on fomites. Upstream farms, wild fish and processing plants were included in assessing the likelihood of introduction by water. The scores for each theme were combined to give separate risk scores for introduction and spread. A matrix was used to combine these to give an overall risk score. A case study for viral haemorrhagic septicaemia is presented. Nine farms that represent a range of farming practices of rainbow trout farms in England and Wales are used as worked examples of the model. The model is suited to risk rank freshwater salmonid farms which are declared free of the pathogen(s) under consideration. The score allocated to a farm does not equate to a quantitative probability estimate of the farm to become infected or spread infection. Nevertheless, the method provides a transparent approach to ranking farms with regards to pathogen transmission risks. The output of the model at a regional or national level allows the allocation of surveillance effort to be risk based. It also provides fish farms with information on how they can reduce their risk score by improving biosecurity. The framework of the model can be applied to different production

  13. Mercury contamination in freshwater, estuarine, and marine fishes in relation to small-scale gold mining in Suriname, South America.

    PubMed

    Mol, J H; Ramlal, J S; Lietar, C; Verloo, M

    2001-06-01

    The extent of mercury contamination in Surinamese food fishes due to small-scale gold mining was investigated by determination of the total mercury concentration in 318 freshwater fishes, 109 estuarine fishes, and 110 fishes from the Atlantic Ocean. High background levels were found in the piranha Serrasalmus rhombeus (0.35 microg Hg x g(-1) muscle tissue, wet mass basis) and the peacock cichlid Cichla ocellaris (0.39 microg x g(-1)) from the Central Suriname Nature Reserve. Average mercury levels in freshwater fishes were higher in piscivorous species than in nonpiscivorous species, both in potentially contaminated water bodies (0.71 and 0.19 microg x g(-1), respectively) and in the control site (0.25 and 0.04 microg x g(-1), respectively). Mercury concentrations in piscivorous freshwater fishes were significantly higher in rivers potentially affected by gold mining than in the control site. In 57% of 269 piscivorous freshwater fishes from potentially contaminated sites, mercury levels exceeded the maximum permissible concentration of 0.5 microg Hg x g(-1). The highest mercury concentrations (3.13 and 4.26 microg x g(-1)) were found in two piranhas S. rhombeus from the hydroelectric reservoir Lake Brokopondo. The high mercury levels in fishes from Lake Brokopondo were to some extent related to gold mining because fishes collected at eastern sites (i.e., close to the gold fields) showed significantly higher mercury concentrations than fishes from western localities. In the estuaries, mercury levels in ariid catfish (0.22 microg x g(-1)) and croakers (0.04-0.33 microg x g(-1)) were distinctly lower than those in piscivorous fishes from contaminated freshwater sites. In the isolated Bigi Pan Lagoon, the piscivores snook Centropomus undecimalis (0.04 microg x g(-1)) and tarpon Megalops atlanticus (0.03 microg x g(-1)) showed low mercury levels. Mercury levels were significantly higher in marine fishes than in estuarine fishes, even with the Bigi Pan fishes excluded

  14. Frequent isolation of Edwardsiella tarda and Pleisiomonas shigelloides from healthy Zairese freshwater fish: a possible source of sporadic diarrhea in the tropics.

    PubMed Central

    Van Damme, L R; Vandepitte, J

    1980-01-01

    The intestinal contents of 59 Zairese freshwater fish were examined for the presence of potential human enteric pathogens. Edwardsiella tarda and Plesiomonas shigelloides were isolated from 57 and 59% of them, respectively. For both microorganisms there was a significant difference between the isolation rates from lake and river fish: whereas E. tarda was much more frequently isolated from lake fish than was P. shigelloides, the reverse was observed for river fish. The authors hypothesize that sporadic cases of tropical diarrhea with E. tarda or P. shigelloides can be traced to contact with or consumption of freshwater fish. PMID:7387150

  15. Variation in freshwater fish assemblages along a regional elevation gradient in the northern Andes, Colombia

    PubMed Central

    Carvajal-Quintero, Juan D; Escobar, Federico; Alvarado, Fredy; Villa-Navarro, Francisco A; Jaramillo-Villa, Úrsula; Maldonado-Ocampo, Javier A

    2015-01-01

    Studies on elevation diversity gradients have covered a large number of taxa and regions throughout the world; however, studies of freshwater fish are scarce and restricted to examining their changes along a specific gradient. These studies have reported a monotonic decrease in species richness with increasing elevation, but ignore the high taxonomic differentiation of each headwater assemblage that may generate high β-diversity among them. Here, we analyzed how fish assemblages vary with elevation among regional elevation bands, and how these changes are related to four environmental clines and to changes in the distribution, habitat use, and the morphology of fish species. Using a standardized field sampling technique, we assessed three different diversity and two structural assemblage measures across six regional elevation bands located in the northern Andes (Colombia). Each species was assigned to a functional group based on its body shape, habitat use, morphological, and/or behavioral adaptations. Additionally, at each sampling site, we measured four environmental variables. Our analyses showed: (1) After a monotonic decrease in species richness, we detected an increase in richness in the upper part of the gradient; (2) diversity patterns vary depending on the diversity measure used; (3) diversity patterns can be attributed to changes in species distribution and in the richness and proportions of functional groups along the regional elevation gradient; and (4) diversity patterns and changes in functional groups are highly correlated with variations in environmental variables, which also vary with elevation. These results suggest a novel pattern of variation in species richness with elevation: Species richness increases at the headwaters of the northern Andes owing to the cumulative number of endemic species there. This highlights the need for large-scale studies and has important implications for the aquatic conservation of the region. PMID:26257874

  16. Cladogenesis and loss of the marine life-history phase in freshwater galaxiid fishes (Osmeriformes: Galaxiidae).

    PubMed

    Waters, J M; Wallis, G P

    2001-03-01

    Switches from migratory (diadromous) to nonmigratory (freshwater) life histories are known to have occurred repeatedly in some aquatic taxa. However, the significance of the loss of diadromy as an initiator for speciation remains poorly understood. The rivers of New Zealand's South Island house a species flock of recently derived nonmigratory galaxiid fishes known as the Galaxias vulgaris complex. Members of this complex are morphologically and genetically similar to the diadromous G. brevipinnis found in New Zealand and southeastern Australia. We hypothesised that South Island's G. vulgaris complex (at least 10 nonmigratory lineages) represents a number of independent radiations from a migratory G. brevipinnis stock, with repeated loss of diadromy. Sequence data were obtained for 31 ingroup samples (G. vulgaris complex and G. brevipinnis) plus four outgroup taxa. A well-resolved phylogeny based on 5039 base pairs of the mitochondrial genome suggests that diadromy has been lost on three separate occasions. Thus, speciation in these galaxiid fishes is partly an incidental phenomenon caused by switches from diadromous to nonmigratory strategies. However, much of the subsequent nonmigratory diversity is monophyletic, suggesting that drainage evolution (vicariance) has also played a major role in cladogenesis. Levels of sequence divergence among major ingroup lineages (1.6-12.7%) suggest that the radiation is considerably older relative to Northern Hemisphere (postglacial) complexes of salmonid, osmerid, and gasterosteid fishes. Sympatric taxa are not monophyletic, suggesting that their coexistence reflects secondary contact rather than sympatric speciation. The monophyly of New Zealand G. brevipinnis is well supported, but both mitochondrial DNA and nuclear sequences indicate that G. brevipinnis is paraphyletic on an intercontinental scale. The divergence (maximum 11.5%) between Tasmanian and New Zealand G. brevipinnis, although large, supports marine dispersal rather

  17. Variation in freshwater fish assemblages along a regional elevation gradient in the northern Andes, Colombia.

    PubMed

    Carvajal-Quintero, Juan D; Escobar, Federico; Alvarado, Fredy; Villa-Navarro, Francisco A; Jaramillo-Villa, Úrsula; Maldonado-Ocampo, Javier A

    2015-07-01

    Studies on elevation diversity gradients have covered a large number of taxa and regions throughout the world; however, studies of freshwater fish are scarce and restricted to examining their changes along a specific gradient. These studies have reported a monotonic decrease in species richness with increasing elevation, but ignore the high taxonomic differentiation of each headwater assemblage that may generate high β-diversity among them. Here, we analyzed how fish assemblages vary with elevation among regional elevation bands, and how these changes are related to four environmental clines and to changes in the distribution, habitat use, and the morphology of fish species. Using a standardized field sampling technique, we assessed three different diversity and two structural assemblage measures across six regional elevation bands located in the northern Andes (Colombia). Each species was assigned to a functional group based on its body shape, habitat use, morphological, and/or behavioral adaptations. Additionally, at each sampling site, we measured four environmental variables. Our analyses showed: (1) After a monotonic decrease in species richness, we detected an increase in richness in the upper part of the gradient; (2) diversity patterns vary depending on the diversity measure used; (3) diversity patterns can be attributed to changes in species distribution and in the richness and proportions of functional groups along the regional elevation gradient; and (4) diversity patterns and changes in functional groups are highly correlated with variations in environmental variables, which also vary with elevation. These results suggest a novel pattern of variation in species richness with elevation: Species richness increases at the headwaters of the northern Andes owing to the cumulative number of endemic species there. This highlights the need for large-scale studies and has important implications for the aquatic conservation of the region. PMID:26257874

  18. Survival of cool and warm freshwater fish following chloramine-T exposure

    USGS Publications Warehouse

    Gaikowski, M.P.; Larson, W.J.; Gingerich, W.H.

    2008-01-01

    Chloramine-T is presently available in the USA to control mortalities associated with bacterial gill disease or external columnaris only through an Investigational New Animal Drug Permit authorized by the US Food and Drug Administration (FDA). Its US approval hinges on FDA's acceptance of several key data, including those describing animal safety. Chloramine-T is presently applied in US aquaculture, by permit only, once daily on consecutive or alternate days for 1??h at 10 to 20??mg/L to control mortalities associated with bacterial gill disease or external columnaris. Our objective was to determine the safety of chloramine-T bath exposures at multiples of the proposed maximum treatment concentration (i.e., 0, 20, 60, 100, and 200??mg/L) administered on four consecutive days at 20????C to lake sturgeon Acipenser fulvescens, northern pike Esox lucius, and walleye Sander vitreum, or at 27????C to channel catfish Ictalurus punctatus, and largemouth bass Micropterus salmoides. All fish were tested as five to eight week old fry except for walleye and channel catfish which were tested as both fry and fingerling (fingerlings were at least four weeks older than the fry tested). Walleye and channel catfish were selected to evaluate the effects of life stage (fry vs. fingerling), temperature (walleye - 15, 20, or 25????C; channel catfish - 22, 27, or 32????C), exposure duration (60 vs. 180??min), and water chemistry (walleye only - reconstituted soft water vs. well water). Except for channel catfish fry, survival was significantly reduced only when fish were treated at 100 or 200??mg/L. Channel catfish fry survival was significantly reduced when exposed at 60??mg/L for 180??min at 27????C. Based on our mortality data, chloramine-T administered once daily for 60??min on four consecutive days at concentrations of up to 20??mg/L is not likely to adversely affect survival of cool or warmwater fish cultured in freshwater. Crown Copyright ?? 2007.

  19. Laboratory Studies of the Short-term Responses of Freshwater Fish to Electromagnetic Fields

    SciTech Connect

    Bevelhimer, Mark S; Cada, Glenn F; Fortner, Allison M; Schweizer, Peter E; Riemer, Kristina P

    2013-01-01

    Hydrokinetic energy technologies are being proposed as an environmentally preferred means of generating electricity from river and tidal currents. Among the potential issues that must be investigated in order to resolve environmental concerns are the effects on aquatic organisms of electromagnetic fields created by underwater generators and transmission cables. The behavioral responses of common freshwater fishes to static and variable electromagnetic fields (EMF) that may be emitted by hydrokinetic projects were evaluated in laboratory experiments. Various fish species were exposed to either static (DC) EMF fields created by a permanent bar magnet or variable (AC) EMF fields created by a switched electromagnet for 48 h, fish locations were recorded with a digital imaging system, and changes in activity level and distribution relative to the magnet position were quantified at 5-min intervals. Experiments with fathead minnows, redear sunfish, striped bass, lake sturgeon, and channel catfish produced mixed results. Except for fathead minnows there was no effect on activity level. Only redear sunfish and channel catfish exhibited a change in distribution relative to the position of the magnet with an apparent attraction to the EMF source. In separate experiments, rapid behavioral responses of paddlefish and lake sturgeon to onset of the AC field were recorded with high-speed video. Paddlefish did not react to a variable, 60-Hz magnetic field like that which would be emitted by an AC generator or cable, but lake sturgeon consistently responded to the variable, AC-generated magnetic field with a variety of altered swimming behaviors. These results will be useful for determining under what circumstances cables or generators need to be positioned to minimize interactions with sensitive species.

  20. Hepatic antioxidative responses to PCDPSs and estimated short-term biotoxicity in freshwater fish.

    PubMed

    Li, Ying; Li, Mei; Shi, Jiaqi; Yang, Xi; Wang, Zunyao

    2012-09-15

    This study evaluated the short-term toxicity of polychlorinated diphenylsulfides (PCDPSs) in freshwater fish. Laboratory experiments were performed to determine the oxidative stress and antioxidative responses of 12 different types of PCDPSs in the liver of goldfish, Carassius auratus. Fish were injected with increasing concentrations (0.1, 1, 10, 100 μg/kg body weight for various PCDPSs and 1, 10, 100 mg/kg for diphenylsulfides (DPS)) of test compounds for 12h, with one group assigned as the control. We simultaneously evaluated the time-dependent effects of PCDPSs on the antioxidant defense system, using Tris-, Penta- and Hepta-CDPS. Fish were acutely injected with either 10 μg/kg of such PCDPSs or corn oil alone (control), and then liver samples were collected at 0.5, 1, 2, 3 and 5d for analysis of antioxidant content. Changes in the activities of superoxide dismutase (SOD), catalase (CAT), and in the levels of malondialdehyde (MDA) were detected, suggesting that PCDPSs exhibit potential biotoxicity. In addition, our data indicated that PCDPS toxicity varies with the degree of substitution and the position of substitution attached to two benzene rings, results that were also partly supported by the time-dependent effects elicited by the Tris-, Penta- and Hepta-CDPSs. In particular, our results indicate that Penta- and Hexa-CDPSs may act as highly toxic contaminants that exhibit striking enzymatic inhibitory activity. Furthermore, our results suggest that altered levels of antioxidant enzymes, including SOD and CAT, along with MDA, may serve as potential biomarkers of PCDPS contamination. PMID:22640874

  1. Residual levels of DDTs and PAHs in freshwater and marine fish from Hong Kong markets and their health risk assessment.

    PubMed

    Cheung, K C; Leung, H M; Kong, K Y; Wong, M H

    2007-01-01

    Axial and ventral muscle from 10 each species of freshwater and marine fish purchased from markets in Hong Kong were analyzed for dichlorodiphenyltrichloroethane (total DDTs including DDE, DDD and DDT) and polycyclic aromatic hydrocarbons (PAHs). Among the 10 freshwater fish species, rice field eel (Monopterus albus) showed significantly higher levels of DDTs in both ventral (125 ng/g wet wt) and axial muscle (127 ng/g wet wt) than the other species. The highest concentration of PAHs was detected in catfish (Clarias fuscus), with 24.8 ng/g in ventral muscle and 9.1 ng/g in axial muscle. As to marine fish, snubnose pompano (Trachinotus blochii) showed significantly higher levels of DDT and its metabolites (1018 ng/g in ventral and 409 ng/g wet wt in axial tissues) than all other marine fish species. The overall concentrations of PAHs in marine fish species were 15.5-57.0 ng/g (axial muscle) and 18.1-118 ng/g wet wt (ventral muscle) where yellow seafin (Acanthopeyrus latus) and golden threadfin bream (Nemipterus virgatus) exhibited the highest concentrations of PAHs in the axial and ventral muscles, respectively. In general, results showed that levels of PAHs in Hong Kong market fish was low and do not expect to cause any concern for human consumption. However, the levels of DDTs in fish samples ranged from 1.10 to 1018 ng/g wet wt, and based on a fish consumption rate of 142.2g/day to calculate the screening value of 14.4 ng/g wet wt for human consumption (USEPA, 2000. Guidance for assessing chemical contaminant, data for use in fish advisories, vol. 1: fish sampling and analysis, third ed. EPA 823-R-95-007. Office of Water, Washington, DC), there were 9 out of 20 (45%) muscle samples of freshwater fish species and 14 out of 20 (70%) muscle samples of marine fish species had elevated levels of DDTs exceeded the screening value. It was also suggested to use ventral muscle for detecting concentrations of persistent organic pollutants in fish. PMID:16870232

  2. Late Pleistocene fishes of the Tennessee River Basin: an analysis of a late Pleistocene freshwater fish fauna from Bell Cave (site ACb-2) in Colbert County, Alabama, USA

    PubMed Central

    Ebersole, Jun A.; Dickinson, William C.; Ciampaglio, Charles N.

    2016-01-01

    The Tennessee River Basin is considered one of the most important regions for freshwater biodiversity anywhere on the globe. The Tennessee River Basin currently includes populations of at least half of the described contemporary diversity of extant North American freshwater fishes, crayfish, mussel, and gastropod species. However, comparatively little is known about the biodiversity of this basin from the Pleistocene Epoch, particularly the late Pleistocene (∼10,000 to 30,000 years B.P.) leading to modern Holocene fish diversity patterns. The objective of this study was to describe the fish assemblages of the Tennessee River Basin from the late Pleistocene using a series of faunas from locales throughout the basin documented from published literature, unpublished reports, and an undocumented fauna from Bell Cave (site ACb-2, Colbert County, AL). Herein we discuss 41 unequivocal taxa from 10 late Pleistocene localities within the basin and include a systematic discussion of 11 families, 19 genera, and 24 identifiable species (28 unequivocal taxa) specific to the Bell Cave locality. Among the described fauna are several extirpated (e.g., Northern Pike Esox lucius, Northern Madtom Noturus stigmosus) and a single extinct (Harelip Sucker Moxostoma lacerum) taxa that suggest a combination of late Pleistocene displacement events coupled with more recent changes in habitat that have resulted in modern basin diversity patterns. The Bell Cave locality represents one of the most intact Pleistocene freshwater fish deposits anywhere in North America. Significant preservational, taphonomic, sampling, and identification biases preclude the identification of additional taxa. Overall, this study provides a detailed look into paleo-river ecology, as well as freshwater fish diversity and distribution leading up to the contemporary biodiversity patterns of the Tennessee River Basin and Mississippi River Basin as a whole. PMID:26855876

  3. Late Pleistocene fishes of the Tennessee River Basin: an analysis of a late Pleistocene freshwater fish fauna from Bell Cave (site ACb-2) in Colbert County, Alabama, USA.

    PubMed

    Jacquemin, Stephen J; Ebersole, Jun A; Dickinson, William C; Ciampaglio, Charles N

    2016-01-01

    The Tennessee River Basin is considered one of the most important regions for freshwater biodiversity anywhere on the globe. The Tennessee River Basin currently includes populations of at least half of the described contemporary diversity of extant North American freshwater fishes, crayfish, mussel, and gastropod species. However, comparatively little is known about the biodiversity of this basin from the Pleistocene Epoch, particularly the late Pleistocene (∼10,000 to 30,000 years B.P.) leading to modern Holocene fish diversity patterns. The objective of this study was to describe the fish assemblages of the Tennessee River Basin from the late Pleistocene using a series of faunas from locales throughout the basin documented from published literature, unpublished reports, and an undocumented fauna from Bell Cave (site ACb-2, Colbert County, AL). Herein we discuss 41 unequivocal taxa from 10 late Pleistocene localities within the basin and include a systematic discussion of 11 families, 19 genera, and 24 identifiable species (28 unequivocal taxa) specific to the Bell Cave locality. Among the described fauna are several extirpated (e.g., Northern Pike Esox lucius, Northern Madtom Noturus stigmosus) and a single extinct (Harelip Sucker Moxostoma lacerum) taxa that suggest a combination of late Pleistocene displacement events coupled with more recent changes in habitat that have resulted in modern basin diversity patterns. The Bell Cave locality represents one of the most intact Pleistocene freshwater fish deposits anywhere in North America. Significant preservational, taphonomic, sampling, and identification biases preclude the identification of additional taxa. Overall, this study provides a detailed look into paleo-river ecology, as well as freshwater fish diversity and distribution leading up to the contemporary biodiversity patterns of the Tennessee River Basin and Mississippi River Basin as a whole. PMID:26855876

  4. Gene trees versus species trees: reassessing life-history evolution in a freshwater fish radiation.

    PubMed

    Waters, Jonathan M; Rowe, Diane L; Burridge, Christopher P; Wallis, Graham P

    2010-10-01

    Mechanisms of speciation are best understood in the context of phylogenetic relationships and as such have often been inferred from single gene trees, typically those derived from mitochondrial DNA (mtDNA) markers. Recent studies, however, have noted the potential for phylogenetic discordance between gene trees and underlying species trees (e.g., due to stochastic lineage sorting, introgression, or selection). Here, we employ a variety of nuclear DNA loci to reassess evolutionary relationships within a recent freshwater fish radiation to reappraise modes of speciation. New Zealand's freshwater-limited Galaxias vulgaris complex is thought to have evolved from G. brevipinnis, a widespread migratory species that retains a plesiomorphic marine juvenile phase. A well-resolved tree, based on four mtDNA regions, previously suggested that marine migratory ability has been lost on 3 independent occasions in the evolution of this species flock (assuming that loss of diadromy is irreversible). Here, we use pseudogene (galaxiid Numt: 1801 bp), intron (S: 903 bp), and exon (RAG-1: 1427 bp) markers, together with mtDNA, to reevaluate this hypothesis of parallel evolution. Interestingly, partitioned Bayesian analysis of concatenated nuclear sequences (3141 bp) and concatenated nuclear and mtDNA (4770 bp) both recover phylogenies implying a single loss of diadromy, not three parallel losses as previously inferred from mtDNA alone. This phylogenetic result is reinforced by a multilocus analysis performed using Bayesian estimation of species trees (BEST) software that estimates the posterior distribution of species trees under a coalescent model. We discuss factors that might explain the apparently misleading phylogenetic inferences generated by mtDNA. PMID:20603441

  5. Selenium:mercury molar ratios in freshwater fish from Tennessee: individual, species, and geographical variations have implications for management.

    PubMed

    Burger, Joanna; Gochfeld, Michael; Jeitner, C; Donio, M; Pittfield, T

    2012-06-01

    Vertebrates, including humans, can experience adverse effects from mercury consumed in fish. Humans often prefer large predatory fish that bioaccumulate high mercury levels. Recent attention has focused on the role of selenium countering mercury toxicity, but there is little research on the selenium:mercury molar ratios in freshwater fish. We examine selenium:mercury molar ratios in freshwater fish from Tennessee at Poplar Creek which receives ongoing inputs of mercury from the Department of Energy's Oak Ridge Y-12 facility. Our objective was to determine variation of the ratios within species that might affect the protectiveness of selenium against mercury toxicity. Within species, the ratio was correlated significantly and positively with fish length only for two species. There was great individual variation in the selenium:mercury molar ratio within each species, except striped bass. The lack of a clear relationship between the selenium:mercury molar ratio and fish length, and the intraspecific variation, suggests that it would be difficult to use the molar ratio in predicting either the risk from mercury toxicity or in devising consumption advisories. PMID:22456727

  6. Selenium:Mercury Molar Ratios in Freshwater Fish from Tennessee: Individual, Species, and Geographical Variations have Implications for Management

    PubMed Central

    Burger, Joanna; Gochfeld, Michael; Jeitner, C.; Donio, M.; Pittfield, T.

    2014-01-01

    Vertebrates, including humans, can experience adverse effects from mercury consumed in fish. Humans often prefer large predatory fish that bioaccumulate high mercury levels. Recent attention has focused on the role of selenium countering mercury toxicity, but there is little research on the selenium:mercury molar ratios in freshwater fish. We examine selenium:mercury molar ratios in freshwater fish from Tennessee at Poplar Creek which receives ongoing inputs of mercury from the Department of Energy’s Oak Ridge Y-12 facility. Our objective was to determine variation of the ratios within species that might affect the protectiveness of selenium against mercury toxicity. Within species, the ratio was correlated significantly and positively with fish length only for two species. There was great individual variation in the selenium:mercury molar ratio within each species, except striped bass. The lack of a clear relationship between the selenium:mercury molar ratio and fish length, and the intraspecific variation, suggests that it would be difficult to use the molar ratio in predicting either the risk from mercury toxicity or in devising consumption advisories. PMID:22456727

  7. Assessing Potential Conservation and Restoration Areas of Freshwater Fish Fauna in the Indian River Basins.

    PubMed

    Bhatt, Jay P; Manish, Kumar; Mehta, Rajender; Pandit, Maharaj K

    2016-05-01

    Conservation efforts globally are skewed toward terrestrial ecosystems. To date, conservation of aquatic ecosystems, in particular fish fauna, is largely neglected. We provide a country-wide assessment of Indian river ecosystems in order to identify and prioritize areas for protection and restoration of freshwater fish fauna. Using various biodiversity and anthropogenic attributes, coupled with tools of ecological modeling, we delineated areas for fish fauna conservation and restoration in the 20 major river basins of India. To do this, we used prioritization analyses and reserve selection algorithms to derive conservation value index (CVI) and vulnerability index (VI) of the river basins. CVI was estimated using endemicity, rarity, conservation value, and taxonomic singularity, while VI was estimated using a disturbance index derived from percent geographic area of the basin under human settlements, human population density, predominant land use, and total number of exotic fish species in each basin. The two indices, CVI and VI, were converted into geo-referenced maps, and each map was super-imposed onto species richness and forest cover maps, respectively. After superimposition, areas with high CVI and low VI shade intensities were delineated for conservation, while areas with high CVI and high VI shade intensities were demarcated for restoration. In view of the importance of freshwater fish for human livelihoods and consumption, and ecosystems of India's rivers, we call for urgent attention to the conservation of their fish fauna along with restoration of their degraded habitats. PMID:26872885

  8. Assessment of risk to humans of bisphenol A in marine and freshwater fish from Pearl River Delta, China.

    PubMed

    Wei, Xi; Huang, Yeqing; Wong, Ming H; Giesy, John P; Wong, Chris K C

    2011-09-01

    Bisphenol A (BPA) is a high production-volume chemical used in the manufacture of a wide variety of consumer products. However it is also a ubiquitous contaminant that can interfere with endocrine systems of wildlife and humans. China is the "world factory" and the Pearl River Delta is the major manufacturing center and is consequently polluted. Concentrations of BPA in meats of marketable fish had not been previously reported for this region. In the study upon which we report here concentrations of BPA were determined in 20 common species of freshwater and marine fish, collected from markets in Hong Kong, SAR, China. A comprehensive analytical method based on SPE extraction and liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was developed, validated and applied. The method limit of detection (LOD) and limit of quantification (LOQ) were 0.5 and 1.25 ng g(-1) dw, respectively. BPA was detected in 19 species of fish at concentrations, ranging from 0.5 to 2.0 ng g(-1) ww. Average daily BPA intake per person ranged from 1.1×10(2) ng d(-1) for marine fish and 2.2×10(2) ng d(-1) for freshwater fish. Concentrations of BPA in fish from Hong Kong markets unlikely would be causing adverse population-level effects in humans. PMID:21700311

  9. Laboratory Studies of the Effects of Static and Variable Magnetic Fields on Freshwater Fish

    SciTech Connect

    Cada, Glenn F; Bevelhimer, Mark S; Fortner, Allison M; Riemer, Kristina P; Schweizer, Peter E

    2012-04-01

    benthic invertebrates (Gill et al. 2005, 2009). It is known that numerous marine and freshwater organisms are sensitive to electrical and magnetic fields, often depending on them for such diverse activities as prey location and navigation (DOE 2009; Normandeau et al. 2011). Despite the wide range of aquatic organisms that are sensitive to EMF and the increasing numbers of underwater electrical transmitting cables being installed in rivers and coastal waters, little information is available to assess whether animals will be attracted, repelled, or unaffected by these new sources of EMF. This knowledge gap is especially significant for freshwater systems, where electrosensitive organisms such as paddlefish and sturgeon may interact with electrical transmission cables. We carried out a series of laboratory experiments to test the sensitivity of freshwater fish and invertebrates to the levels of EMF that are expected to be produced by HK projects in rivers. In this context, EM fields are likely to be emitted primarily by generators in the water column and by transmission cables on or buried in the substrate. The HK units will be located in areas of high-velocity waters that are used as only temporary habitats for most riverine species, so long-term exposure of fish and benthic invertebrates to EMF is unlikely. Rather, most aquatic organisms will be briefly exposed to the fields as they drift downstream or migrate upstream. Because the exposure of most aquatic organisms to EMF in a river would be relatively brief and non-lethal, we focused our investigations on detecting behavioral effects. For example, attraction to the EM fields could result in prolonged exposures to the fields or the HK rotor. On the other hand, avoidance reactions might hinder upstream migrations of fish. The experiments reported here are a continuation of studies begun in FY 2010, which focused on the potential effects of static magnetic fields on snails, clams, and fathead minnows (Cada et al. 2011

  10. A population assessment of mercury exposure from two cities of Pakistan with respect to freshwater and marine fish consumption.

    PubMed

    Shah, Abdul Qadir; Kazi, Tasneem Gul; Afridi, Hassan Imran; Arain, Mohammad Balal

    2016-06-01

    In this study, we aimed to estimate the level of mercury (Hg) in scalp hair samples of human subjects and its association with consumption of sea- and freshwater fish species. The scalp hairs were collected from both genders (male and female) aged between 15 and 50 years (n = 200), living in coastal areas of Karachi, who mostly consumed sea fish species, referred to as exposed subjects. For comparison purposes, scalp hair samples of both genders (n = 160) were collected from the inhabitants of Karachi and Hyderabad cities who consumed freshwater fish species termed as referent subjects. The frequently consumed fresh and marine fish species were also collected. The level of Hg was determined in fish and scalp hair samples by cold vapor atomic absorption spectrometry, prior to ultrasonic-assisted acid digestion in a mixture of nitric acid and hydrogen peroxide. The validity of methodology was checked by certified reference material (CRM) BCR 397 (human hair) and DORM-2. The concentrations of Hg in sea- and freshwater fish were found in the range of 1.47-2.09 and 0.402-0.676 μg/g, respectively. The exposed subjects had significantly elevated levels of Hg in scalp hair samples (1.8-4.3 μg/g) as compared to referent subjects (0.87-1.95 μg/g) (p < 0.001). A significant positive correlation was obtained between the concentration of Hg in hair and age of study population. Exposed and referent female subjects had higher levels of Hg in scalp hair than that in males of both study groups (p = 0.02-0.031). PMID:25147303

  11. Extreme Genetic Structure in a Small-Bodied Freshwater Fish, the Purple Spotted Gudgeon, Mogurnda adspersa (Eleotridae)

    PubMed Central

    Hughes, Jane M.; Real, Kathryn M.; Marshall, Jonathan C.; Schmidt, Daniel J.

    2012-01-01

    Freshwater fish are a group that is especially susceptible to biodiversity loss as they often exist naturally in small, fragmented populations that are vulnerable to habitat degradation, pollution and introduction of exotic species. Relatively little is known about spatial dynamics of unperturbed populations of small-bodied freshwater fish species. This study examined population genetic structure of the purple spotted gudgeon (Mogurnda adspersa, Eleotridae), a small-bodied freshwater fish that is widely distributed in eastern Australia. The species is threatened in parts of its range but is common in coastal streams of central Queensland where this study took place. Microsatellite (msat) and mitochondrial DNA (mtDNA) variation was assessed for nine sites from four stream sections in two drainage basins. Very high levels of among population structure were observed (msat FST = 0.18; mtDNA ΦST = 0.85) and evidence for contemporary migration among populations was rare and limited to sites within the same section of stream. Hierarchical structuring of variation was best explained by stream section rather than by drainage basin. Estimates of contemporary effective population size for each site was low (range 28 – 63, Sibship method), but compared favorably with similar estimates for other freshwater fish species, and there was no genetic evidence for inbreeding or recent population bottlenecks. In conclusion, within a stable part of its range, M adspersa exists as a series of small, demographically stable populations that are highly isolated from one another. Complimentary patterns in microsatellites and mtDNA indicate this structuring is the result of long-term processes that have developed over a remarkably small spatial scale. High population structure and limited dispersal mean that recolonisation of locally extinct populations is only likely to occur from closely situated populations within stream sections. Limited potential for recolonisation should be

  12. Spinitectus mexicanus n. sp. (Nematoda : Cystidicolidae) from the intestine of the freshwater fish Heterandria bimaculata in Mexico.

    PubMed

    Caspeta-Mandujano, J M; Moravec, F; Salgado-Maldonado, G

    2000-02-01

    A new nematode, Spinitectus mexicanus n. sp., is described on the basis of the specimens recovered from the intestine of Heterandria bimaculata (Heckel) (Poeciliidae, Cyprinodontiformes) from 3 rivers of the Papaloapan River basin (type locality La Basura River), Los Tuxtlas, Veracruz State, Mexico. It differs from its congeners mainly in having the spination of the cuticle separated into 4 longitudinal sectors, each with posteriorly diminishing numbers of larger spines at the anterior part of body. It is the first species of Spinitectus described from a poeciliid fish and the second reported from freshwater fishes in Mexico. PMID:10701569

  13. Freshwater fish faunas, habitats and conservation challenges in the Caribbean river basins of north-western South America.

    PubMed

    Jiménez-Segura, L F; Galvis-Vergara, G; Cala-Cala, P; García-Alzate, C A; López-Casas, S; Ríos-Pulgarín, M I; Arango, G A; Mancera-Rodríguez, N J; Gutiérrez-Bonilla, F; Álvarez-León, R

    2016-07-01

    The remarkable fish diversity in the Caribbean rivers of north-western South America evolved under the influences of the dramatic environmental changes of neogene northern South America, including the Quechua Orogeny and Pleistocene climate oscillations. Although this region is not the richest in South America, endemism is very high. Fish assemblage structure is unique to each of the four aquatic systems identified (rivers, streams, floodplain lakes and reservoirs) and community dynamics are highly synchronized with the mono-modal or bi-modal flooding pulse of the rainy seasons. The highly seasonal multispecies fishery is based on migratory species. Freshwater fish conservation is a challenge for Colombian environmental institutions because the Caribbean trans-Andean basins are the focus of the economic development of Colombian society, so management measures must be directed to protect aquatic habitat and their connectivity. These two management strategies are the only way for helping fish species conservation and sustainable fisheries. PMID:27401480

  14. Larvae of Contracaecum sp. (Nematoda: Anisakidae) in the threatened freshwater fish Sandelia capensis (Anabantidae) in South Africa.

    PubMed

    Moravec, Franti Ek; van Rensburg, Candice Jansen; Van As, Liesl L

    2016-08-01

    Third-stage larvae of the nematode genus Contracaecum Railliet et Henry, 1912 (Contracaecum sp.) were, for the first time, recorded from the abdominal cavity of the threatened endemic freshwater fish Sandelia capensis (Cuvier) in South Africa. The larval morphology indicated that they belong to a species of which the adults are parasitic in fish-eating birds. Although the nematode seems to be a common parasite of S. capensis in the locality under study (prevalence 23%), the low intensity of infection recorded (1 to 4) and the generally known low pathogenicity of Contracaecum larvae in fish indicate that this parasite probably does not represent a danger to the local population of this threatened fish species. PMID:27503922

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

    PubMed

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

    2016-04-01

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

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

    USGS Publications Warehouse

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

    2016-01-01

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

  17. Automated detection of broadband clicks of freshwater fish using spectro-temporal features.

    PubMed

    Kottege, Navinda; Jurdak, Raja; Kroon, Frederieke; Jones, Dean

    2015-05-01

    Large scale networks of embedded wireless sensor nodes can passively capture sound for species detection. However, the acoustic recordings result in large amounts of data requiring in-network classification for such systems to be feasible. The current state of the art in the area of in-network bioacoustics classification targets narrowband or long-duration signals, which render it unsuitable for detecting species that emit impulsive broadband signals. In this study, impulsive broadband signals were classified using a small set of spectral and temporal features to aid in their automatic detection and classification. A prototype system is presented along with an experimental evaluation of automated classification methods. The sound used was recorded from a freshwater invasive fish in Australia, the spotted tilapia (Tilapia mariae). Results show a high degree of accuracy after evaluating the proposed detection and classification method for T. mariae sounds and comparing its performance against the state of the art. Moreover, performance slightly improves when the original signal was down-sampled from 44.1 to 16 kHz. This indicates that the proposed method is well-suited for detection and classification on embedded devices, which can be deployed to implement a large scale wireless sensor network for automated species detection. PMID:25994683

  18. In vitro probiotic profiling of novel Enterococcus faecium and Leuconostoc mesenteroides from Tunisian freshwater fishes.

    PubMed

    El-Jeni, Rim; El Bour, Monia; Calo-Mata, Pilar; Böhme, Karola; Fernández-No, Inmaculada C; Barros-Velázquez, Jorge; Bouhaouala-Zahar, Balkiss

    2016-01-01

    Novel lactic acid bacteria isolated from different organs of freshwater fish were examined for their potential application as probiotics in raw and processed foods. Four isolates of Enterococcus faecium and Leuconostoc mesenteroides were identified at the molecular level by 16S rRNA sequencing and random amplification of polymorphic DNA - polymerase chain reaction, and their antimicrobial activity against a panel of pathogens and food-poisoning bacteria was investigated. The whole bacteriocins of the 4 isolates were characterized by enterobacterial repetitive intergenic consensus sequences in PCR. The isolates exhibited high inhibitory activities against food-borne pathogens and spoilage microbial species and have significant probiotic profiles, since they survived at pH 3.0 and in the presence of bile salts, pancreatin, and pepsin, without any detectable hemolytic activity. Further, moderate heat resistance, adhesion ability to steel surfaces, and sensitivity to clinically relevant antimicrobial agents were revealed for all the isolates. These results highlight the specific probiotic properties of the strains and give evidence for potential application in minimally processed foods subjected to moderate heat processing. PMID:26651241

  19. Descriptions of diplostomid metacercariae (Digenea: Diplostomidae) from freshwater fishes in the Tshwane area.

    PubMed

    Moema, Esmey B E; King, Pieter H; Rakgole, Johnny N; Baker, Chantélle

    2013-01-01

    The metacercarial (larval) stages of diplostomid digeneans are known to inhabit freshwater fish, causing tissue damage in the process. Due to their widespread diversity, little is known about their life cycle. The classification of these parasitic stages to the species level using only the morphology is very challenging due to the lack of genitalia; they are regarded to be the most important structures in the identification of these organisms. In this study, additional morphological information through light and scanning electron microscopy is given for two different diplostomids found in the cranial cavity of Clarias gariepinus and the vitreous chambers of Tilapia sparrmanii and Pseudocrenilabrus philander. The diplostomid metacercaria inhabiting the cranial cavity of Clarias gariepinus was morphologically identified as Diplostomulum (Tylodelphys) mashonense and an unknown metacercaria of the genus Diplostomum was found in the vitreous chambers of Pseudocrenilabrus philander and Tilapia sparrmanii. Both parasitic species' 28S recombinant deoxyribonucleic acid genomic regions were successfully amplified using Dig 125/1500R primer pairs. The assay yielded a product of approximately 1300 base pairs as seen on the gel images. There were 14 nucleotide differences over the entire analysed sequences resulting in a 1.1% (14/1273) nucleotide difference. In line with the morphological characteristics of these parasites, there seemed to be a slight difference in their genetic make-up. The application of molecular techniques on digenetic trematodes seems very promising and may yield great potential in future descriptions of morphologically similar parasitic species. PMID:24396918

  20. Molecular diversity of Germany's freshwater fishes and lampreys assessed by DNA barcoding.

    PubMed

    Knebelsberger, Thomas; Dunz, Andreas R; Neumann, Dirk; Geiger, Matthias F

    2015-05-01

    This study represents the first comprehensive molecular assessment of freshwater fishes and lampreys from Germany. We analysed COI sequences for almost 80% of the species mentioned in the current German Red List. In total, 1056 DNA barcodes belonging to 92 species from all major drainages were used to (i) build a reliable DNA barcode reference library, (ii) test for phylogeographic patterns, (iii) check for the presence of barcode gaps between species and (iv) evaluate the performance of the barcode index number (BIN) system, available on the Barcode of Life Data Systems. For over 78% of all analysed species, DNA barcodes are a reliable means for identification, indicated by the presence of barcode gaps. An overlap between intra- and interspecific genetic distances was present in 19 species, six of which belong to the genus Coregonus. The Neighbour-Joining phenogram showed 60 nonoverlapping species clusters and three singleton species, which were related to 63 separate BIN numbers. Furthermore, Barbatula barbatula, Leucaspius delineatus, Phoxinus phoxinus and Squalius cephalus exhibited remarkable levels of cryptic diversity. In contrast, 11 clusters showed haplotype sharing, or low levels of divergence between species, hindering reliable identification. The analysis of our barcode library together with public data resulted in 89 BINs, of which 56% showed taxonomic conflicts. Most of these conflicts were caused by the use of synonymies, inadequate taxonomy or misidentifications. Moreover, our study increased the number of potential alien species in Germany from 14 to 21 and is therefore a valuable groundwork for further faunistic investigations. PMID:25186809

  1. Fish species introductions provide novel insights into the patterns and drivers of phylogenetic structure in freshwaters.

    PubMed

    Strecker, Angela L; Olden, Julian D

    2014-03-01

    Despite long-standing interest of terrestrial ecologists, freshwater ecosystems are a fertile, yet unappreciated, testing ground for applying community phylogenetics to uncover mechanisms of species assembly. We quantify phylogenetic clustering and overdispersion of native and non-native fishes of a large river basin in the American Southwest to test for the mechanisms (environmental filtering versus competitive exclusion) and spatial scales influencing community structure. Contrary to expectations, non-native species were phylogenetically clustered and related to natural environmental conditions, whereas native species were not phylogenetically structured, likely reflecting human-related changes to the basin. The species that are most invasive (in terms of ecological impacts) tended to be the most phylogenetically divergent from natives across watersheds, but not within watersheds, supporting the hypothesis that Darwin's naturalization conundrum is driven by the spatial scale. Phylogenetic distinctiveness may facilitate non-native establishment at regional scales, but environmental filtering restricts local membership to closely related species with physiological tolerances for current environments. By contrast, native species may have been phylogenetically clustered in historical times, but species loss from contemporary populations by anthropogenic activities has likely shaped the phylogenetic signal. Our study implies that fundamental mechanisms of community assembly have changed, with fundamental consequences for the biogeography of both native and non-native species. PMID:24452027

  2. Osmoregulatory adaptations of freshwater air-breathing snakehead fish (Channa striata) after exposure to brackish water.

    PubMed

    Nakkrasae, La-iad; Wisetdee, Khanitha; Charoenphandhu, Narattaphol

    2015-07-01

    NaCl-rich rock salt dissolved in natural water source leads to salinity fluctuation that profoundly affects freshwater ecosystem and aquatic fauna. The snakehead (Channa striata) can live in saline water, but the osmoregulatory mechanisms underlying this ability remain unclear. Herein, we found that exposure to salinities ≥ 10‰ NaCl markedly elevated plasma cortisol and glucose levels, and caused muscle dehydration. In a study of time-dependent response after being transferred from fresh water (0‰ NaCl, FW) to salt-dissolved brackish water (10‰ NaCl, SW), FW-SW, cortisol increased rapidly along with elevations of plasma glucose and lactate. Interestingly, plasma cortisol returned to baseline after prolonged exposure, followed by a second peak that probably enhanced the branchial Na(+)/K(+)-ATPase activity. Under SW-FW condition, Na(+)/K(+)-ATPase activity was not altered as compared to SW-adapted fish. In conclusion, salinity change, especially FW-SW, induced a stress response and hence cortisol release in C. striata, which might increase plasma glucose and lactate to energize the branchial Na(+)/K(+)-ATPase. PMID:25899744

  3. Fish species introductions provide novel insights into the patterns and drivers of phylogenetic structure in freshwaters

    PubMed Central

    Strecker, Angela L.; Olden, Julian D.

    2014-01-01

    Despite long-standing interest of terrestrial ecologists, freshwater ecosystems are a fertile, yet unappreciated, testing ground for applying community phylogenetics to uncover mechanisms of species assembly. We quantify phylogenetic clustering and overdispersion of native and non-native fishes of a large river basin in the American Southwest to test for the mechanisms (environmental filtering versus competitive exclusion) and spatial scales influencing community structure. Contrary to expectations, non-native species were phylogenetically clustered and related to natural environmental conditions, whereas native species were not phylogenetically structured, likely reflecting human-related changes to the basin. The species that are most invasive (in terms of ecological impacts) tended to be the most phylogenetically divergent from natives across watersheds, but not within watersheds, supporting the hypothesis that Darwin's naturalization conundrum is driven by the spatial scale. Phylogenetic distinctiveness may facilitate non-native establishment at regional scales, but environmental filtering restricts local membership to closely related species with physiological tolerances for current environments. By contrast, native species may have been phylogenetically clustered in historical times, but species loss from contemporary populations by anthropogenic activities has likely shaped the phylogenetic signal. Our study implies that fundamental mechanisms of community assembly have changed, with fundamental consequences for the biogeography of both native and non-native species. PMID:24452027

  4. Effects of predatory fish on survival and behavior of larval gopher frogs (Rana capito) and Southern Leopard Frogs (Rana sphenocephala)

    USGS Publications Warehouse

    Gregoire, D.R.; Gunzburger, M.S.

    2008-01-01

    Southern Leopard Frogs, Rana sphenocephala, are habitat generalists occurring in virtually all freshwater habitats within their geographic range, whereas Gopher Frogs, Rana capito, typically breed in ponds that do not normally contain fish. To evaluate the potential for predation by fish to influence the distribution of these species, we conducted a randomized factorial experiment. We examined the survival rate and behavior of tadpoles when exposed to Warmouth Sunfish, Lepomis gulosus, Banded Sunfish, Enneacanthus obesus, and Eastern Mosquitofish, Gambusia holbrooki. We also conducted a choice experiment to examine the survival rate of the two species of tadpoles when a predator is given a choice of both species simultaneously. Lepomis gulosus consumed the most tadpoles and ate significantly more tadpoles of R. capito than R. sphenocephala. Gambusia holbrooki injured the most tadpoles, especially R. capito. Enneacanthus obesus did not have an effect on behavior or survival of either anuran species. Tadpoles of both anurans increased hiding when in the presence of L. gulosus and G. holbrooki, but a greater proportion of R. capito hid than did R. sphenocephala. Our results suggest that R. capito are more vulnerable to predation by fish than are R. sphenocephala. The introduction of fish may play a role in population declines of certain anurans breeding in normally fish-free wetlands, and even small fish, such as mosquitofish, may have significant negative effects on the tadpoles of R. capito. Copyright 2008 Society for the Study or Amphibians and Reptiles.

  5. SE Asian freshwater fish population and networks: the impacts of climatic and environmental change on a vital resource

    NASA Astrophysics Data System (ADS)

    Santos, Rita; Parsons, Daniel; Cowx, Ian

    2016-04-01

    The Mekong River is the 10th largest freshwater river in the world, with the second highest biodiversity wealth, behind the much larger Amazon basin. The fisheries activity in the Lower Mekong countries counts for 2.7 million tons of fish per year, with an estimated value worth up to US 7 billion. For the 60 million people living in the basin, fish represent their primary source of economic income and protein intake, with an average per capita consumption estimated at 45.4 Kg. The proposed hydropower development in the basin is threatening its sustainability and resilience. Such developments affect fish migration patterns, hydrograph flood duration and magnitudes and sediment flux. Climate change is also likely to impact the basin, exacerbating the issues created by development. As a monsoonal system, the Mekong River's pronounced annual flood pulse cycle is important in creating variable habitat for fish productivity. Moreover, the annual flood also triggers fish migration and provides vital nutrients carried by the sediment flux. This paper examines the interactions between both dam development and climate change scenarios on fish habitat and habitat connectivity, with the aim of predicting how these will affect fish species composition and fisheries catch. The project will also employ Environmental DNA (eDNA) to quantify and understand the species composition of this complex and large freshwater system. By applying molecular analysis, it is possible to trace species abundance and migration patterns of fish and evaluate the ecological networks establish between an inland system. The aim of this work is to estimate, using process-informed models, the impacts of the proposed dam development and climate change scenarios on the hydrological and hydraulic conditions of habitat availability for fish. Furthermore, it will evaluate the connectivity along the Mekong and its tributaries, and the importance of maintaining these migration pathways, used by a great diversity

  6. Water Quality Influences Reproduction in Female Mosquitofish (Gambusia holbrooki) from Eight Florida Springs

    PubMed Central

    Edwards, Thea M.; Miller, Hilary D.; Guillette, Louis J.

    2006-01-01

    Contamination of freshwater ecosystems with nitrate is a growing global concern. Although nitrate pollution is recognized as a cause of aquatic eutrophication, few studies have examined the possible physiological impacts of nitrate exposure. In this study, we surveyed several reproductive variables of viviparous female Gambusia holbrooki (Poeciliidae) captured from eight springs in Florida. The eight springs represent a gradient of nitrate contamination (1–5 mg/L nitrate–nitrogen). We had two objectives in this study: to describe reproductive biology of female mosquitofish in the springs and to understand reproductive variation in the context of water quality, particularly the nitrate concentration. Our data show a significant negative association between nitrate and both dry weight of developing embryos and rate of reproductive activity among mature females. In addition, variation in Gambusia condition index and embryo number and dry weight was related to temperature variation, and hepatic weight was negatively related to dissolved oxygen concentration. Finally, we observed that many of the measured reproductive variables were interrelated and changeable, depending on gestational stage. Specifically, we provide evidence that maternal support of the embryo occurs at least during the first two thirds of gestation and that female fecundity is affected by an apparent tradeoff between embryo size and embryo number. PMID:16818249

  7. Relative impacts of the fragmentation and spatial structure of habitats on freshwater fish distributions: application on French watersheds (Invited)

    NASA Astrophysics Data System (ADS)

    Le Pichon, C.; Belliard, J.; Talès, E.; Gorges, G.; Clément, F.

    2009-12-01

    Most of the rivers of the Ile de France region, intimately linked with the megalopolis of Paris, are severely altered and freshwater fishes are exposed to habitat alteration, reduced connectivity and pollution. Several species thus present fragmented distributions and decreasing densities. In this context, the European Water Framework Directive (2000) has goals of hydrosystems rehabilitation and no further damage. In particular, the preservation and restoration of ecological connectivity of river networks is a key element for fish populations. These goals require the identification of natural and anthropological factors which influence the spatial distribution of species. We have proposed a riverscape approach, based on landscape ecology concepts, combined with a set of spatial analysis methods to assess the multiscale relationships between the spatial pattern of fish habitats and processes depending on fish movements. In particular, we used this approach to test the relative roles of spatial arrangement of fish habitats and the presence of physical barriers in explaining fish spatial distributions in a small rural watershed (106 km2). We performed a spatially continuous analysis of fish-habitat relationships. Fish habitats and physical barriers were mapped along the river network (33 km) with a GPS and imported into a GIS. In parallel, a longitudinal electrofishing survey of the distribution and abundance of fishes was made using a point abundance sampling scheme. Longitudinal arrangement of fish habitats were evaluated using spatial analysis methods: patch/distance metrics and moving window analysis. Explanatory models were developed to test the relative contribution of local environmental variables and spatial context in explaining fish presence. We have recorded about 100 physical barriers, on average one every 330 meters; most artificial barriers were road pipe culverts, falls associated with ponds and sluice gates. Contrasted fish communities and densities

  8. Determination of moderately polar arsenolipids and mercury speciation in freshwater fish of the River Elbe (Saxony, Germany).

    PubMed

    Arroyo-Abad, Uriel; Pfeifer, Matthias; Mothes, Sibylle; Stärk, Hans-Joachim; Piechotta, Christian; Mattusch, Jürgen; Reemtsma, Thorsten

    2016-01-01

    Arsenic and mercury are frequent contaminants in the environment and care must be taken to limit their entrance into the food chain. The toxicity of both elements strongly depends upon their speciation. Total amounts of As and Hg as well as their species were analyzed in muscle and liver of 26 fishes of seven freshwater fish species caught in the River Elbe. The median concentrations of As were 162 μg kg(-1) w.w. in liver and 92 μg kg(-1) w.w. in muscle. The median concentrations of total Hg were 241 μg kg(-1) w.w. in liver and 256 μg kg(-1) w.w. in muscle. While this level of Hg contamination of the freshwater fish in the River Elbe is significantly lower than 20 years ago, it exceeds the recommended environmental quality standard of 20 μg Hg kg(-1) w.w. by a factor of 5-50. However, the European maximum level of 500 μg Hg kg(-1) for fish for human consumption is rarely exceeded. Arsenic-containing fatty acids and hydrocarbons were determined and partially identified in methanolic extracts of the fish by HPLC coupled in parallel to ICP-MS (element specific detection) and ESI-Q-TOF-MS (molecular structure detection). While arsenobetaine was the dominant As species in the fish, six arsenolipids were detected and identified in the extracts of liver tissue in common bream (Abramis brama), ide (Leuciscus idus), asp (Aspius aspius) and northern pike (Esox lucius). Four arsenic-containing fatty acids (AsFA) and two arsenic-containing hydrocarbons (AsHC) are reported in freshwater fish for the first time. With respect to mercury the more toxic MeHg(+) was the major species in muscle tissue (>90% of total Hg) while in liver Hg(2+) and MeHg(+) were of equal importance. The results show the high relevance of element speciation in addition to the determination of total element concentrations to correctly assess the burden of these two elements in fish. PMID:26552521

  9. Mercury and selenium concentrations in muscle tissue of different species of predatory freshwater fish and correlation between these elements.

    PubMed

    Strapáč, Imrich; Sokol, Jozef; Žatko, Daniel; Baranová, Mária

    2012-01-01

    Concentrations of total mercury and selenium were determined in 49 and 42 muscle tissue samples, respectively, of six species of predatory freshwater fish, dace (Leuciscus leuciscus), pike perch (Sander lucioperca), pike (Esox lucius), European catfish (Silurus glanis), rainbow trout (Oncorhynchus mykiss) and asp (Aspius aspius). Muscle selenium concentration did not correlate with the corresponding total mercury concentration (R² < 0.198) in all examined predatory fish species. There was an inverse correlation between the ratio Se/Hg content and the total mercury content in the muscle tissues of dace, pike perch, pike, European catfish and asp. The muscle tissue of rainbow trout exhibits a linear correlation between the ratio Se/Hg content and the total mercury content. The total mercury concentration of all examined samples did not exceed the hygienic limit for Hg for predatory fish. PMID:24779785

  10. Scales of freshwater fish Labeo rohita as bioindicators of water pollution in Tung Dhab Drain, Amritsar, Punjab, India.

    PubMed

    Kaur, Rajbir; Dua, Anish

    2015-01-01

    This study examined the impact of municipal wastewater on scale morphology of freshwater fish Labeo rohita. Fish were exposed to sublethal concentrations (17.7, 26.6, or 35.4%) of municipal wastewater for durations of 15, 30, and 60 d. Recovery experiments were also performed for a duration of 60 d. Scales were extracted after respective exposure periods, cleaned, and processed for scanning electron microscopy. Results showed concentration- and exposure duration-dependent alterations in the morphology of scales. Severe damage was observed at the anterior and posterior portions of scales in the form of lepidontal breakage and uprooting, destructions at the base of circuli and radii along with complete structural loss in the focal region and adjacent circuli and radii, and alterations in structure of tubercles. Data indicate that scales of fish L. rohita may be employed as bioindicators of water pollution and could be incorporated into water monitoring surveillance. PMID:25734766

  11. Acute lethal toxicity of some reference chemicals to freshwater fishes of Scandinavia

    SciTech Connect

    Oikari, A.O.J.

    1987-07-01

    Relevance of the choice of a test organism intended to be representative for a given environment seems to be under continual debate in aquatic ecotoxicology. For instance, it is commonly argue that acute toxicity tests with rainbow trout, the species most often recommended as a standard cold water teleost, were not representative for Nordic countries because the species is an alien in local faunas. A comparative study with several freshwater species was therefore initiated to clarify the validity of this assumption. As a first approximation, standard LC 50 assays were conducted. The species used were chosen only on the basis of their local availability, i.e, they randomly represented the fish fauna of Nordic inland waters. Furthermore, inter-species variation of toxicity response was compared with certain other, quantitatively more important, intra-species sources of variability affecting the toxicity of chemicals. Use of reference toxicants has been recommended as a means of standardizing bioassays. Compounds, characteristic of effluents from the pulp and paper industry, were selected for the present study. The toxicity of organic acids such a phenols and resin acids, as well as that of pupmill effluents, strongly depends on water pH. Because of the possibility that species differences could exist in this respect, effects of water acidity on toxicity of these types of substances to a randomly selected local species was investigated. Finally, as an example of the biological source of assay variability, the effect of yolk absorption was studied with a subsequent crisis period due to moderate starvation under laboratory conditions.

  12. Establishment Patterns of Non-native Fishes: Lessons from the Duluth-Superior Harbor and Lower St. Louis River, an Invasion-prone Great Lakes Freshwater Estuary

    EPA Science Inventory

    The St. Louis River freshwater estuary which drains into western Lake Superior and includes the Duluth-Superior (MN-WI) harbor, has a long history of non-native fish introductions. From 1985 to 2002, seven new fishes were identified in the estuary, an unprecedented rate of non-n...

  13. Analysis of retinol, 3-hydroxyretinol and 3,4-didehydroretinol in North American farm-raised freshwater fish liver, muscle and feed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vitamin A (retinol; ROL) is an essential micronutrient in fish, vital for vision and cell growth. Freshwater fish species also synthesize uncommon forms of VA, such as 3,4-didehydrotinol (DROL) and 3-hydroxyretinol (3ROL) that have biological activity. However, little information is available abou...

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

    PubMed

    Kraus, Richard T; Jones, R Christian

    2012-05-01

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

  15. Molecular and structural composition of phospholipid membranes in livers of marine and freshwater fish in relation to temperature.

    PubMed Central

    Dey, I; Buda, C; Wiik, T; Halver, J E; Farkas, T

    1993-01-01

    The compositions and physical states of the liver phospholipids of marine and freshwater fish adapted to relatively constant but radically different temperatures were investigated. Fish adapted to low temperature (5-10 degrees C) accumulated more unsaturated fatty acids than those in a warm (25-27 degrees C) environment. There were no measurable differences in the gross fatty acid compositions of the total liver phospholipids from identical thermal environments. Docosahexaenoic acid (22:6) did not seem to participate in the process of adaptation. Cold adaptation was coincidental with oleic acid (18:1) accumulation, preferentially in the phosphatidylethanolamine. Determination of the molecular species composition of phosphatidylethanolamine revealed a 2- to 3-fold and 10-fold increase in the level of 18:1/22:6 and 18:1/20:5 species, respectively. ESR spectroscopy revealed a 7-10% compensation in the ordering state of native phospholipids with temperature. Combination of 16:0/22:6 phosphatidylcholine with phosphatidylethanolamines of cold-adapted marine fish showed a drastic fluidization near the C-2 segment of the bilayer, but not in the deeper regions. An appropriate combination (75:25) of phosphatidylcholines from warmth-adapted marine fish with phosphatidylethanolamines from cold-adapted marine fish mimicked a 100% adaptational efficacy in the C-2 segment as compared with the phosphatidylethanolamines of warmth-adapted marine fish. A specific role of 18:1/22:6 phosphatidylethanolamine in controlling membrane structure and physical state with thermal adaptation is proposed. PMID:8356045

  16. An inventory of coastal freshwater fishes from Amapá highlighting the occurrence of eight new records for Brazil

    PubMed Central

    Melo, Bruno F.; Benine, Ricardo C.; Britzke, Ricardo; Gama, Cecile S.; Oliveira, Claudio

    2016-01-01

    Abstract The Amazon Basin occupies a vast portion of northern South America and contains some of the highest species richness in the world. The northern Brazilian state of Amapá is delimited by the Amazonas River to the south, the Oyapock River to the northern boundary with French Guyana, and the Atlantic northeastern coast to Amazon estuary. Despite several expeditions to the Amazon in recent decades, little is known about the freshwater ichthyofauna from Amapá, with records limited to local inventories and species descriptions. This paper presents a compilation of the freshwater fish diversity sampled in fifteen sites covering two major Amapá ecoregions during the dry season of 2015. 120 species representing eight orders and 40 families are reported upon in this work. Eight species appear for the first time in the Brazilian territory providing new information for future conservation status evaluations. PMID:27551225

  17. Cross-Cordillera exchange mediated by the Panama Canal increased the species richness of local freshwater fish assemblages.

    PubMed

    Smith, Scott A; Bell, Graham; Bermingham, Eldredge

    2004-09-22

    Completion of the Panama Canal in 1914 breached the continental divide and set into motion a natural experiment of unprecedented magnitude by bringing previously isolated freshwater fish communities into contact. The construction of a freshwater corridor connecting evolutionarily isolated communities in Pacific and Caribbean watersheds dramatically increased the rate of dispersal, without directly affecting species interactions. Here, we report that a large fraction of species have been able to establish themselves on the other side of the continental divide, whereas no species have become extinct, leading to a local increase in species richness. Our results suggest that communities are not saturated and that competitive exclusion does not occur over the time-scale previously envisioned. Moreover, the results of this unintentional experiment demonstrate that community composition and species richness were regulated by the regional process of dispersal, rather than by local processes such as competition and predation. PMID:15347510

  18. An inventory of coastal freshwater fishes from Amapá highlighting the occurrence of eight new records for Brazil.

    PubMed

    Melo, Bruno F; Benine, Ricardo C; Britzke, Ricardo; Gama, Cecile S; Oliveira, Claudio

    2016-01-01

    The Amazon Basin occupies a vast portion of northern South America and contains some of the highest species richness in the world. The northern Brazilian state of Amapá is delimited by the Amazonas River to the south, the Oyapock River to the northern boundary with French Guyana, and the Atlantic northeastern coast to Amazon estuary. Despite several expeditions to the Amazon in recent decades, little is known about the freshwater ichthyofauna from Amapá, with records limited to local inventories and species descriptions. This paper presents a compilation of the freshwater fish diversity sampled in fifteen sites covering two major Amapá ecoregions during the dry season of 2015. 120 species representing eight orders and 40 families are reported upon in this work. Eight species appear for the first time in the Brazilian territory providing new information for future conservation status evaluations. PMID:27551225

  19. Fish diets in a freshwater-deprived semiarid estuary (The Coorong, Australia) as inferred by stable isotope analysis

    NASA Astrophysics Data System (ADS)

    Lamontagne, S.; Deegan, B. M.; Aldridge, K. T.; Brookes, J. D.; Geddes, M. C.

    2016-09-01

    In 2007, high rates of water extraction combined with a regional drought stopped freshwater discharge to the Coorong, a ∼120 km estuarine and coastal lagoon system at the outlet of the River Murray (Australia). The sources of organic matter sustaining the Coorong food web in the absence of river-borne organic matter and nutrient inputs were evaluated by measuring δ13C, δ15N and δ34S in large-bodied fish and their prey. In general, the δ34S of the food web (mean = 11.3‰; range = 4.32-18.9‰) suggested a comparable contribution from autochthonous pelagic (∼21‰) and benthic (<5‰) primary production. A relatively high δ13C in all organisms (-20 to -9.2‰) was also consistent with a dominant contribution from autochtonous sources to the food web. A Bayesian mixing model framework (SIMMR) was used to estimate the diet of large-bodied fish for statistically-determined prey groups based on their similarity in isotopic composition. Argyrosomus japonicus preyed primarily on Fish Group 1 (small pelagic fish like galaxiids and Hyperlophus vittatus), Rhombosolea tapirina on Invertebrate Group 2 (polychaetes like Capitella spp.) but Acanthopagrus butcheri fed on a wide variety of fish and invertebrate groups. A partial switch in diet to other prey groups suggested larger Ar. japonicus fed on larger prey, such as crabs and adult Aldrichetta forsteri. Despite being numerically abundant at the time, Fish Group 2 (benthic species) was a relatively low proportion of large-bodied fish diets. This probably reflected the tendency of some salt-tolerant members of this group (such as Atherinosoma microstoma) to prefer hypersaline habitats, which the large-bodied fish avoided. As the heavily preyed-on Fish Group 1 included species with a marine component to their life-cycle, marine productivity may also help to maintain this estuarine ecosystem in the absence of river-borne organic matter inputs.

  20. Evaluation of Common Angling-Induced Sources of Epithelial Damage for Popular Freshwater Sport Fish using Fluorescein

    SciTech Connect

    Colotelo, Alison HA; Cooke, Steven J.

    2011-05-01

    Angling is a popular recreational activity across the globe and a large proportion of fish captured by anglers are released due to voluntary or mandatory catch-and-release practices. The handling associated with hook removal and return of the fish to their environment can cause physical damage to the epidermal layer of the fish which may affect the condition and survival of released fish. This study investigated possible sources of epithelial damage associated with several different handling methods (i.e. landing net types, interactions with different boat floor surfaces, tournament procedures) commonly used in recreational angling for two popular freshwater sport fish species, largemouth bass (Micropterus salmoides) and northern pike (Esox lucius). Epithelial damage was examined using fluorescein, a non-toxic dye, which has been shown to detect latent epithelial damage. Northern pike exhibited extensive epithelial damage after exposure to several of the induced treatments (i.e., interaction with a carpeted surface, knotted nylon net, and line rolling) but relatively little epithelial damage when exposed to others (i.e., knotless rubber nets, smooth boat surfaces, or lip gripping devices). Largemouth bass did not show significant epithelial damage for any of the treatments, with the exception of fish caught in a semi-professional live release tournament. The detection of latent injuries using fluorescein can be an important management tool as it provides visual examples of potential damage that can be caused by different handling methods. Such visualizations can be used to encourage fish friendly angler behaviour and enhance the survival and welfare of released fish. It can also be used to test new products that are intended to or claim to reduce injury to fish that are to be released. Future research should evaluate the relationship between different levels of epithelial damage and mortality across a range of environmental conditions.

  1. An Androgenic Agricultural Contaminant Impairs Female Reproductive Behaviour in a Freshwater Fish

    PubMed Central

    Saaristo, Minna; Tomkins, Patrick; Allinson, Mayumi; Allinson, Graeme; Wong, Bob B. M.

    2013-01-01

    Endocrine disrupting chemicals (EDCs) are a large group of environmental pollutants that can interfere with the endocrine system function of organisms at very low levels. One compound of great concern is trenbolone, which is widely used as a growth promoter in the cattle industry in many parts of the world. The aim of this study was to test how short-term (21-day) exposure to an environmentally relevant concentration of 17β-trenbolone (measured concentration 6 ng/L) affects reproductive behaviour and fin morphology in the eastern mosquitofish (Gambusia holbrooki). The mosquitofish is a sexually dimorphic livebearer with males inseminating females using their modified anal fin, the gonopodium, as an intromittent organ. Although the species has a coercive mating system, females are able to exert some control over the success of male mating attempts by selectively associating with, or avoiding, certain males over others. We found that females exposed to trenbolone approached males less and spent more time swimming away from males than non-exposed (control) females. By contrast, we found no difference in the behaviour of exposed and non-exposed males. Furthermore, exposure did not affect the anal fin morphology of males or females. This is the first study to demonstrate that exposure to an androgenic EDC can impair female (but not male) behaviour. Our study illustrates how anthropogenic contaminants can have sex-specific effects, and highlights the need to examine the behavioural responses of environmental contaminants in both sexes. PMID:23671634

  2. Sex ratio variation shapes the ecological effects of a globally introduced freshwater fish.

    PubMed

    Fryxell, David C; Arnett, Heather A; Apgar, Travis M; Kinnison, Michael T; Palkovacs, Eric P

    2015-10-22

    Sex ratio and sexual dimorphism have long been of interest in population and evolutionary ecology, but consequences for communities and ecosystems remain untested. Sex ratio could influence ecological conditions whenever sexual dimorphism is associated with ecological dimorphism in species with strong ecological interactions. We tested for ecological implications of sex ratio variation in the sexually dimorphic western mosquitofish, Gambusia affinis. This species causes strong pelagic trophic cascades and exhibits substantial variation in adult sex ratios. We found that female-biased populations induced stronger pelagic trophic cascades compared with male-biased populations, causing larger changes to key community and ecosystem responses, including zooplankton abundance, phytoplankton abundance, productivity, pH and temperature. The magnitude of such effects indicates that sex ratio is important for mediating the ecological role of mosquitofish. Because both sex ratio variation and sexual dimorphism are common features of natural populations, our findings should encourage broader consideration of the ecological significance of sex ratio variation in nature, including the relative contributions of various sexually dimorphic traits to these effects. PMID:26490793

  3. Fish community structure in freshwater karstic water bodies of the Sian Ka'an Reserve in the Yucatan peninsula, Mexico

    USGS Publications Warehouse

    Zambrano, L.; Vazquez-Dominguez, E.; Garcia-Bedoya, D.; Loftus, W.F.; Trexler, J.C.

    2006-01-01

    We evaluated the relationship between limnetic characteristics and fish community structure (based on species richness, abundance and individual size) in contrasting but interconnected inland aquatic habitats of freshwater karstic wetlands in the Yucatan peninsula, Mexico. In the western hemisphere, freshwater karstic wetlands are found in south-eastern Mexico, northern Belize, western Cuba, Andros Island, Bahamas and the Everglades of southern Florida. Only in the Everglades have fish communities been well described. Karstic wetlands are typically oligotrophic because calcium carbonate binds phosphorus, making it relatively unavailable for plants. Fourteen permanent and seasonally flooded water bodies were sampled in both wet and dry seasons in Sian Ka'an Biosphere Reserve, in the Mexican state of Quintana Roo. Water systems were divided by morphology in four groups: cenotes with vegetation (CWV), cenotes without vegetation (CNV), wetlands (WTL), and temporal cenotes (TPC). Discriminant analysis based on physical characteristics such as turbidity, temperature, depth and oxygen confirmed that these habitats differed in characteristics known to influence fish communities. A sample-based rarefaction test showed that species richness was significantly different between water systems groups, showing that WTL and CWV had higher richness values than CNV and TPC. The most abundant fish families, Poeciliidae, Cichlidae and Characidae, differed significantly in average size among habitats and seasons. Seasonal and inter-annual variation, reflecting temporal variation in rainfall, strongly influenced the environmental differences between shallow and deep habitats, which could be linked to fish size and life cycles. Five new records of species were found for the reserve, and one new record for Quintana Roo state. ?? 2006 by Verlag Dr. Friedrich Pfeil.

  4. Where Are All the Fish: Potential of Biogeographical Maps to Project Current and Future Distribution Patterns of Freshwater Species

    PubMed Central

    Markovic, Danijela; Freyhof, Jörg; Wolter, Christian

    2012-01-01

    The dendritic structure of river networks is commonly argued against use of species atlas data for modeling freshwater species distributions, but little has been done to test the potential of grid-based data in predictive species mapping. Using four different niche-based models and three different climate change projections for the middle of the 21st century merged pairwise as well as within a consensus modeling framework, we studied the variability in current and future distribution patterns of 38 freshwater fish species across Germany. We used grid-based (11×11 km) fish distribution maps and numerous climatic, topographic, hydromorphologic, and anthropogenic factors derived from environmental maps at a finer scale resolution (250 m–1 km). Apart from the explicit predictor selection, our modeling framework included uncertainty estimation for all phases of the modeling process. We found that the predictive performance of some niche-based models is excellent independent of the predictor data set used, emphasizing the importance of a well-grounded predictor selection process. Though important, climate was not a primary key factor for any of the studied fish species groups, in contrast to substrate preferences, hierarchical river structure, and topography. Generally, distribution ranges of cold-water and warm-water species are expected to change significantly in the future; however, the extent of changes is highly uncertain. Finally, we show that the mismatch between the current and future ranges of climatic variables of more than 90% is the most limiting factor regarding reliability of our future estimates. Our study highlighted the underestimated potential of grid cell information in biogeographical modeling of freshwater species and provides a comprehensive modeling framework for predictive mapping of species distributions and evaluation of the associated uncertainties. PMID:22792361

  5. TOXICITY OF TEXTILE MILL EFFLUENTS TO FRESHWATER AND ESTUARINE ALGAE, CRUSTACEANS AND FISHES

    EPA Science Inventory

    The toxicity of secondary waste effluents from textile manufacturing plants was determined with freshwater (Selenastrum capricornutum, Daphnia pulex, Pimephales promelus) and estuarine (Skeletonema costatum, Palaemonetes pugio, Cyprinodon variegatus) organisms. Daphnia pulex was ...

  6. Trichodina nobilis Chen, 1963 and Trichodina reticulata Hirschmann et Partsch, 1955 from ornamental freshwater fishes in Brazil.

    PubMed

    Martins, M L; Marchiori, N; Roumbedakis, K; Lami, F

    2012-05-01

    In the present work Trichodina reticulata and T. nobilis (Ciliophora: Trichodinidae) are morphologically characterised from ornamental freshwater fish culture in the State of Santa Catarina, Brazil. The prevalence of infection and a list of comparative measurements are discussed. We examined "southern platyfish" Xiphophorus maculatus (n = 35), "goldfish" Carassius auratus (n = 31), "guppy" Poecilia reticulata (n = 20), "sailfin molly" Poecilia latipinna (n = 6), "beta" Betta splendens (n = 2) and "spotted headstander" Chilodus punctatus (n = 1). After being anesthetised in a benzocaine solution, fishes were examined for parasitological evaluation. A total of 51.57% fishes were parasitised by Trichodina spp. Carassius auratus was the most parasitised species, followed by X. maculatus and P. reticulata. Beta splendens, C. punctatus and P. latipinna were not parasitised by any trichodinid species. Two species of Trichodina were collected from the skin of fish: T. nobilis was found in C. auratus, P. reticulata and X. maculatus and T. reticulata was only observed in C. auratus. The importance of adequate handling in ornamental fish culture are also discussed. PMID:22735135

  7. Climate warming reduces fish production and benthic habitat in Lake Tanganyika, one of the most biodiverse freshwater ecosystems.

    PubMed

    Cohen, Andrew S; Gergurich, Elizabeth L; Kraemer, Benjamin M; McGlue, Michael M; McIntyre, Peter B; Russell, James M; Simmons, Jack D; Swarzenski, Peter W

    2016-08-23

    Warming climates are rapidly transforming lake ecosystems worldwide, but the breadth of changes in tropical lakes is poorly documented. Sustainable management of freshwater fisheries and biodiversity requires accounting for historical and ongoing stressors such as climate change and harvest intensity. This is problematic in tropical Africa, where records of ecosystem change are limited and local populations rely heavily on lakes for nutrition. Here, using a ∼1,500-y paleoecological record, we show that declines in fishery species and endemic molluscs began well before commercial fishing in Lake Tanganyika, Africa's deepest and oldest lake. Paleoclimate and instrumental records demonstrate sustained warming in this lake during the last ∼150 y, which affects biota by strengthening and shallowing stratification of the water column. Reductions in lake mixing have depressed algal production and shrunk the oxygenated benthic habitat by 38% in our study areas, yielding fish and mollusc declines. Late-20th century fish fossil abundances at two of three sites were lower than at any other time in the last millennium and fell in concert with reduced diatom abundance and warming water. A negative correlation between lake temperature and fish and mollusc fossils over the last ∼500 y indicates that climate warming and intensifying stratification have almost certainly reduced potential fishery production, helping to explain ongoing declines in fish catches. Long-term declines of both benthic and pelagic species underscore the urgency of strategic efforts to sustain Lake Tanganyika's extraordinary biodiversity and ecosystem services. PMID:27503877

  8. Suppression of osteoclastic activities by calcitonin in the scales of goldfish (freshwater teleost) and nibbler fish (seawater teleost).

    PubMed

    Suzuki, N; Suzuki, T; Kurokawa, T

    2000-01-01

    Using a tartrate-resistant acid phosphatase (TRACP) activity, the effects of calcitonin (CT) and estradiol-17beta(E(2)) on osteoclastic activities in cultured scales of goldfish (freshwater fish) and nibbler fish (seawater fish) were examined. In mature male and female goldfish, scales were collected and incubated in Earle's minimun essential medium (MEM) supplemented with either CT (100 ng/ml) or E(2) (100 ng/ml). In both sexes, CT suppressed TRACP activities in the scales, whereas E(2) increased them. When CT (100 ng/ml) and E(2) (100 ng/ml) were added simultaneously to MEM, TRACP activities in the scales did not change as compared with the control. Similar results were obtained with the scales of female nibbler fish. In goldfish, furthermore, the activation of scale TRACP by E(2) was suppressed, depending on CT concentrations (100 pg/ml to 1 microg/ml). In fish reproduction, this function of CT may be useful to protect scales from excess degradation of calcium at vitellogenesis. PMID:10704727

  9. Fish-borne zoonotic trematodes in cultured and wild-caught freshwater fish from the Red River Delta, Vietnam.

    PubMed

    Phan, Van Thi; Ersbøll, Annette Kjaer; Bui, Te Quang; Nguyen, Hang Thi; Murrell, Darwin; Dalsgaard, Anders

    2010-11-01

    Nam Dinh province in Red River Delta, Vietnam, is an endemic area for the human liver fluke Clonorchis sinensis, but little is known about its occurrence in the fish intermediate host in this region. A cross-sectional study was carried out to identify fish-borne zoonotic trematodes (FZT) species diversity and to estimate the prevalence and infection densities of FZT in three major types of fish: cultured species and self-recruiting species from family ponds and wild-caught species from irrigation canals in Nam Dinh province. A total of 714 wild-caught fish from canals and 829 fish from family ponds were examined for FZT infection. Only a single fish from a pond was infected with Cl. sinensis. The intestinal fluke Haplorchis pumilio was very common and found in more than 50% of fish irrespective of origin. Four other intestinal FZT species were found at low prevalence (<4.0%) except Procerovum varium, which was found in 14.4% of wild-caught fish. There was no significant difference (p > 0.05) in FZT prevalence in cultured fish (64.3%) compared with wild-caught fish (68.9%), nor between cultured fish species (65.1%) and self-recruiting species obtained from ponds (58.1%). The prevalence of FZT in silver carp (Hypophthalmichthys molitrix) (82.7%), grass carp (Ctenopharyngodon idellus) (76.9%), and mrigal (Cirrhinus mrigala) (63.8%) was significantly higher than that in rohu (Labeo rohita) (49.1%) (p < 0.001). The density of FZT metacercariae in fish from canals (0.56 metacercariae/g) was significantly higher (p < 0.001) than that in fish from ponds (0.03 metacercariae/g). The frequent occurrence of intestinal flukes in all fish types indicates that wild-caught and cultured fish are equally at risk of infection with FZT, particularly in species commonly used in Nam Dinh to prepare raw fish dishes. These results underscore the need for greater awareness of the risk from raw fish dishes among public health agencies and consumers. PMID:20370427

  10. A new species of Dermoergasilus Ho & Do, 1982 (Copepoda: Ergasilidae) from freshwater fishes in the south-west of Western Australia.

    PubMed

    Hassan, Marina; Jones, Brian; Lymbery, Alan J

    2009-10-01

    A new species of Dermoergasilus Ho & Do, 1982 is described from freshwater fish hosts in the south west of Western Australia. D. occidentalis n. sp. differs from previously described species in the genus principally by the armature of the legs. The new species was found on the gills of the freshwater cobbler Tandanus bostocki Whitely and western minnow Galaxias occidentalis Ogilby in two different river systems. PMID:19731098

  11. Inventory of the freshwater fishes from a densely collected area in South America-a case study of the current knowledge of Neotropical fish diversity.

    PubMed

    Bertaco, Vinicius A; Ferrer, Juliano; Carvalho, Fernando R; Malabarba, Luiz R

    2016-01-01

    We herein analyse the history of the description of the freshwater fish fauna from three drainages in one of the most densely collected areas of Brazil, and possibly of South America, the Rio Grande do Sul State, southern Brazil. An updated inventory of the freshwater fish species from rio Uruguay (partial) in Brazil, Laguna dos Patos (complete) and rio Tramandaí basins (complete) is presented. We found the number of new species described in these drainages increased nearly 56% since 1981, reaching a total of 422 species, but even now 10% of this number still corresponds to undescribed species. This rate of species description suggests that previous estimates of the Neotropical fish fauna are low, and we predict a final number of Neotropical fishes larger than the largest prediction estimate (8,000 species), after other regions of South and Central Americas become densely sampled. We discuss and attempt to demonstrate that species diversity knowledge is historically and strictly related to collecting efforts. We also demonstrate that the ecoregions in eastern South America with the highest density of species per area correspond to the areas more densely sampled in collections, and this may represent a bias in such kinds of analyses. This uneven sampling in Brazilian regions is apparently associated with the uneven distribution of Zoological research centers in different regions of the country. Small-sized species represents an important source of new species, along with little explored regions or little explored habitats, sometimes associated with restricted range species, and species complexes that need revisionary work. In contrast to other Neotropical regions, Atheriniformes are relatively diverse, sharing the fifth place in species richness with Gymnotiformes, and there is a remarkably high number of species of Rivulidae. Eight species are endemic to the rio Tramandaí drainage, 68 to the Laguna dos Patos system, and 78 to the rio Uruguay drainage. Almost 10

  12. Helminth parasites of freshwater fishes from Cuatro Ciénegas, Coahuila, in the Chihuahuan Desert of Mexico: inventory and biogeographical implications.

    PubMed

    Aguilar-Aguilar, Rogelio; Martínez-Aquino, Andrés; Espinosa-Pérez, Héctor; Pérez-Ponce de León, Gerardo

    2014-06-01

    As part of an ongoing inventory of the helminth parasites of freshwater fishes in Mexico, 570 individual fish were collected between Apr 2008 and Oct 2011 in 26 localities along the Cuatro Ciénegas region in Coahuila State, northern Mexico. Seventeen species of hosts, mostly corresponding to Nearctic freshwater elements, were studied. A total of 8324 individual worms were collected during this survey, representing 25 species of helminths, of which 9 were digeneans, 3 monogeneans, 3 acanthocephalans, 9 nematodes and 1 cestode. Most of the records in this checklist represent new host or locality records. The information provided in this checklist may be helpful for our understanding of the biodiversity and historical biogeography of this host-parasite system, because in the Cuatro Ciénegas region occur a Nearctic freshwater fish fauna, along with Neotropical and endemic elements, and from a biogeographical point of view, this may represent a transitional area. PMID:24952970

  13. Bioaccumulation and distribution of /sup 95m/Tc in an experimental freshwater pond

    SciTech Connect

    Blaylock, B.G.; Frank, M.L.

    1981-01-01

    An acute release of /sup 95m/Tc was made to a small experimental freshwater pond to determine the behavior of technetium in a freshwater ecosystem. The objectives of the study were (1) to determine the distribution of /sup 95m/Tc in the components of the ecosystem and (2) to determine the concentration in freshwater biota. Prior to the release of /sup 95m/Tc, the pond was stocked with aquatic macrophytes, fish, and invertebrates. All components of the pond were sampled for a period of 37 d. Analyses of filtered and unfiltered water samples showed that /sup 95m/Tc did not sorb significantly to particulates suspended in the water but remained dissolved. Sediments accumulated /sup 95m/Tc slowly as the experiment progressed. In the biota, periphyton accumulated /sup 95m/Tc rapidly, reaching the highest concentration (3482 dpm/g dry wt) 4 h after the release and maintaining a relatively high concentration throughout the experiment. Fish and invertebrates accumulated /sup 95m/Tc gradually. Elimination studies and tissue analyses showed that a large percentage of the body burden was in the digestive system of all fish, suggesting that fish were accumulating /sup 95m/Tc through the food chain. Biological half-lives determined from elimination studies for carp (Cyprinus carpio), mosquitofish (Gambusia affinis), and snails (Helisoma sp.) were 2.5, 4.3, and 21.3 d, respectively. Calculated concentration factors for the same species were 11 for carp, 75 for mosquito fish, and 121 for snails. The estimated size of the biomass components in the ecosystem in descending order were: periphyton, macrophytes, invertebrates, fish, and algae. Based on biomass estimates and concentrations of the /sup 95m/Tc in the aquatic biota, approximately 1% of the /sup 95m/Tc accumulated in the biota.

  14. Effects of nutritional status on metabolic rate, exercise and recovery in a freshwater fish

    SciTech Connect

    Gingerich, Andrew J.; Philipp, D. P.; Suski, C. D.

    2010-11-20

    The influence of feeding on swimming performance and exercise recovery in fish is poorly understood. Examining swimming behavior and physiological status following periods of feeding and fasting is important because wild fish often face periods of starvation. In the current study, researchers force fed and fasted groups of largemouth bass (Micropterus salmoides) of similar sizes for a period of 16 days. Following this feeding and fasting period, fish were exercised for 60 s and monitored for swimming performance and physiological recovery. Resting metabolic rates were also determined. Fasted fish lost an average of 16 g (nearly 12%) of body mass, while force fed fish maintained body mass. Force fed fish swam 28% further and required nearly 14 s longer to tire during exercise. However, only some physiological conditions differed between feeding groups. Resting muscle glycogen concentrations was twofold greater in force fed fish, at rest and throughout recovery, although it decreased in both feeding treatments following exercise. Liver mass was nearly three times greater in force fed fish, and fasted fish had an average of 65% more cortisol throughout recovery. Similar recovery rates of most physiological responses were observed despite force fed fish having a metabolic rate 75% greater than fasted fish. Results are discussed as they relate to largemouth bass starvation in wild systems and how these physiological differences might be important in an evolutionary context.

  15. Concentration-dependent toxicity effect of SDBS on swimming behavior of freshwater fishes.

    PubMed

    Zhang, Ying; Ma, Jing; Zhou, Siyun; Ma, Fang

    2015-07-01

    Sodium dodecyl benzene sulfonate (SDBS) is a kind of widely used anionic surfactant and its discharge may pose potential risk to the receiving aquatic ecosystem. The aim of our study is to investigate the toxic effect of SDBS on fish swimming behavior quantitatively, followed by examination whether there are significant differences of swimming behavior among applied fish species (i.e. zebra fish (Danio rerio), Japanese medaka (Oryzias latipes) and red carp (Cyprinus carpio)). The swimming speed and vertical position were analyzed after the fish exposed to SDBS aiming to reflect the toxicity of SDBS on fish. Our results showed that the swimming behavior of three fishes was significantly affected by SDBS, although there were slight differences of swimming pattern changes among three fish species when they exposed to the same concentration of SDBS. It could be seen that red carp, one of the native fish species in China, can be used as a model fish to reflect the water quality changes as well as zebra fish and Japanese medaka which are commonly used as model fishes. Our study also illustrated that the swimming behavior monitoring may have a good application prospect in pre-warning of water quality. PMID:26093194

  16. Spatial extent and dynamics of dam impacts on tropical island freshwater fish assemblages

    USGS Publications Warehouse

    Cooney, Patrick B.; Kwak, Thomas J.

    2013-01-01

    Habitat connectivity is vital to the persistence of migratory fishes. Native tropical island stream fish assemblages composed of diadromous species require intact corridors between ocean and riverine habitats. High dams block fish migration, but low-head artificial barriers are more widespread and are rarely assessed for impacts. Among all 46 drainages in Puerto Rico, we identified and surveyed 335 artificial barriers that hinder fish migration to 74.5% of the upstream habitat. We also surveyed occupancy of native diadromous fishes (Anguillidae, Eleotridae, Gobiidae, and Mugilidae) in 118 river reaches. Occupancy models demonstrated that barriers 2 meters (m) high restricted nongoby fish migration and extirpated those fish upstream of 4-m barriers. Gobies are adapted to climbing and are restricted by 12-m barriers and extirpated upstream of 32-m barriers. Our findings quantitatively illustrate the extensive impact of low-head structures on island stream fauna and provide guidance for natural resource management, habitat restoration, and water development strategies.

  17. Leptospira infections in freshwater fish in Morogoro Tanzania: a hidden public health threat.

    PubMed

    Mgode, Georgis F; Mhamphi, Ginethon G; Katkweba, Abdul S; Thomas, Michael

    2014-04-01

    Leptospirosis caused by spirochete bacterium of genus Leptospira affects humans and animals worldwide. Rodents are major reservoirs of leptospires whereas wetland and aquatic migratory birds also carry and transmit leptospires. Leptospirosis studies in fish are lacking in African countries despite favourable environment and abundant reservoirs, which can spread leptospires into aquatic habitats and infect fish. The objectives of this study were to determine presence of Leptospira in fish; the prevalent Leptospira serovars and whether are related to serovars reported in animals; and to ascertain potential public health risk. Live tilapia, catfish and eel fish (n = 48) were caught in Mindu Dam in Morogoro Municipality in eastern Tanzania. Blood sample was collected using syringes and needles to obtain serum for serological detection of leptospirosis using gold standard microagglutination test utilizing local and reference Leptospira serovars Sokoine, Kenya, Pomona and Hebdomadis. Twenty-six fish (54.2%) were positive for serovar Kenya (29.2%) and Sokoine (25%). Leptospira prevalence was high in both catfish (58.3%) and tilapia fish (47.8%). Thus, different fish types are infected with Leptospira found in animals. Fish could be source of Leptospira infection to humans since tilapia and catfish are the common fish type widely consumed in Tanzania. Further study covering lakes, rivers and dams is required to better understand the prevalence of Leptospira in fish and actual public health threats. PMID:26875305

  18. Survey of parasitic fauna of different ornamental freshwater fish species in Iran.

    PubMed

    Adel, Milad; Ghasempour, Fatemeh; Azizi, Hamid Reza; Shateri, Mohamad Hadi; Safian, Ahmad Reza

    2015-01-01

    Parasitic diseases are harmful and limiting factors in breeding and rearing ornamental fish industry. In this study, 400 apparently healthy ornamental fishes from five species (each species 80 specimens) including: Goldfish (Carassius auratus), guppy (Poecilia reticulate), angelfish (Pterophyllum scalare), discus (Symphsodon discus) and sailfin mollies (Poecilia latipinna) was obtained from a local ornamental fish farm in the north of Iran during 2011 to 2012. The primary purpose of this study was to determine the parasitic infections of aquarium fish in Iran. For this purpose, fish were first examined for ectoparasites using wet mount under a light microscope. Then, the alimentary ducts of fish were observed under light and stereo microscope. In survey of different infection rates for different parasitic infections in examining fish: Dactylogyrus sp., Gyrodactylus sp., Ichthyophthirius multifiliis Trichodina reticulata, Capillaria sp. and Lernaea cyprinacea were collected from five species. All five fish species had Monogenea (Gyrodactylidae and Dactylogyridae) in their skins and gills, the highest prevalence was observed in C. auratus and the lowest was in P. scalare and S. discus. Also, Capillaria sp. was reported as a first record from the abdominal cavity of P. scalare in Iran. Our findings revealed that the protozoal infections are very common among aquarium fishes. Although, no gross pathology was observed among infected fishes, but it is likely that in case of any changes in the environment, then parasitic infections could be harmful. PMID:25992255

  19. Fish composition and species richness in eastern South American coastal lagoons: additional support for the freshwater ecoregions of the world.

    PubMed

    Petry, A C; Guimarães, T F R; Vasconcellos, F M; Hartz, S M; Becker, F G; Rosa, R S; Goyenola, G; Caramaschi, E P; Díaz de Astarloa, J M; Sarmento-Soares, L M; Vieira, J P; Garcia, A M; Teixeira de Mello, F; de Melo, F A G; Meerhoff, M; Attayde, J L; Menezes, R F; Mazzeo, N; Di Dario, F

    2016-07-01

    The relationships between fish composition, connectivity and morphometry of 103 lagoons in nine freshwater ecoregions (FEOW) between 2·83° S and 37·64° S were evaluated in order to detect possible congruence between the gradient of species richness and similarities of assemblage composition. Most lagoons included in the study were <2 km(2) , with a maximum of 3975 km(2) in surface area. Combined surface area of all lagoons included in the study was 5411 km(2) . Number of species varied locally from one to 76. A multiple regression revealed that latitude, attributes of morphometry and connectivity, and sampling effort explained a large amount of variability in species richness. Lagoon area was a good predictor of species richness except in low latitude ecoregions, where lagoons are typically small-sized and not affected by marine immigrants, and where non-native fish species accounted for a significant portion of species richness. Relationships between species and area in small-sized lagoons (<2 km(2) ) is highly similar to the expected number in each ecoregion, with systems located between 18·27° S and 30·15° S attaining higher levels of species richness. Similarities in species composition within the primary, secondary and peripheral or marine divisions revealed strong continental biogeographic patterns only for species less tolerant or intolerant to salinity. Further support for the FEOW scheme in the eastern border of South America is therefore provided, and now includes ecotonal systems inhabited simultaneously by freshwater and marine species of fishes. PMID:27401481

  20. Climate change impacts on freshwater fish, coral reefs, and related ecosystem services in the United States

    EPA Science Inventory

    We analyzed the potential physical and economic impacts of climate change on freshwater fisheries and coral reefs in the United States, examining a reference scenario and two policy scenarios that limit global greenhouse gas (GHG) emissions. We modeled shifts in suitable habitat ...

  1. A new species of Philometra Costa, 1845 (Nematoda: Philometridae) from the freshwater fish (red piranha) Pygocentrus nattereri Kner (Characidae) in Amazonia, Brazil.

    PubMed

    Cárdenas, Melissa Q; Moravec, František; Fernandes, Berenice M M; Morais, Aprigio Mota

    2012-10-01

    A new nematode species, Philometra nattereri n. sp. (Philometridae), is described from female specimens found in the oculo-orbits and nasal cavity of the red piranha Pygocentrus nattereri Kner (Characiformes: Characidae) from five lakes in Central Amazonia, Brazil, collected in 2008 and 2009 (overall prevalence 12%, intensity 1-3 nematodes per fish). Based on light and scanning electron microscopical examination, the new species differs from most other congeners parasitising freshwater fishes in that its oesophageal gland extends anteriorly far anterior to the level of the nerve-ring, in the presence of 14 small cephalic papillae arranged in two circles and in having two minute caudal projections. This is the first species of Philometra Costa, 1845 reported from fishes of the family Characidae and the second valid species of this genus parasitic in freshwater fishes of Brazil and South America. PMID:22983801

  2. Presence of lactobacilli in the intestinal content of freshwater fish from a river and from a farm with a recirculation system.

    PubMed

    Bucio, Adolfo; Hartemink, Ralf; Schrama, Johan W; Verreth, Johan; Rombouts, Frans M

    2006-08-01

    Lactobacilli are Gram-positive and catalase negative rods commonly found in lactic acid fermented foods and in the gastrointestinal tract of mammals and birds. Few studies have described lactobacilli in freshwater fish. We analysed the presence of lactobacilli in the intestines of young and adult freshwater fish inhabiting a river environment and from fish reared in an aquaculture unit with a water recirculation system. Various species of lactobacilli were present in relatively high number in the intestines of edible fresh water fish from the river, especially in the warm season but in low numbers in the cold season. Lactobacilli were scarcely found in the intestines of edible farmed fish reared in a recirculation system in warm water. Lactobacilli are reported for the first time from the intestines of wild European eel, perch, rudd, ruffe, bleak, silver bream, chub, somnul and farmed African catfish. The two first fishes, and the last one are highly valuable species for fisheries and aquaculture. Additionally, improved methods for storage and bacteriological analysis of fish intestinal content are described. The natural presence of lactic acid bacteria in fish may be of great interest in producing fermented fish products worldwide. PMID:16943040

  3. Heavy metals: confounding factors in the response of New Zealand freshwater fish assemblages to natural and anthropogenic acidity.

    PubMed

    Greig, Hamish S; Niyogi, Dev K; Hogsden, Kristy L; Jellyman, Phillip G; Harding, Jon S

    2010-07-15

    Acidification of freshwaters is a global phenomenon, occurring both through natural leaching of organic acids and through human activities from industrial emissions and mining. The West Coast of the South Island, New Zealand, has both naturally acidic and acid mine drainage (AMD) streams enabling us to investigate the response of fish communities to a gradient of acidity in the presence and absence of additional stressors such as elevated concentrations of heavy metals. We surveyed a total of 42 streams ranging from highly acidic (pH 3.1) and high in heavy metals (10 mg L(-)(1) Fe; 38 mg L(-)(1) Al) to circum-neutral (pH 8.1) and low in metals (0.02 mg L(-)(1) Fe; 0.05 mg L(-)(1) Al). Marked differences in pH and metal tolerances were observed among the 15 species that we recorded. Five Galaxias species, Anguilla dieffenbachii and Anguillaaustralis were found in more acidic waters (pH<5), while bluegill bullies (Gobiomorphus hubbsi) and torrentfish (Cheimarrichthys fosteri) were least tolerant of low pH (minimum pH 6.2 and 5.5, respectively). Surprisingly, the strongest physicochemical predictor of fish diversity, density and biomass was dissolved metal concentrations (Fe, Al, Zn, Mn and Ni) rather than pH. No fish were detected in streams with dissolved metal concentrations >2.7 mg L(-)(1) and nine taxa were only found in streams with metal concentrations <1 mg L(-)(1). The importance of heavy metals as critical drivers of fish communities has not been previously reported in New Zealand, although the mechanism of the metal effects warrants further study. Our findings indicate that any remediation of AMD streams which seeks to enable fish recolonisation should aim to improve water quality by raising pH above approximately 4.5 and reducing concentrations of dissolved Al and Fe to <1.0 mg L(-)(1). PMID:20478612

  4. Cobalt Chloride Treatment Used to Ablate the Lateral Line System Also Impairs the Olfactory System in Three Freshwater Fishes

    PubMed Central

    Butler, Julie M.; Field, Karen E.; Maruska, Karen P.

    2016-01-01

    Fishes use multimodal signals during both inter- and intra-sexual displays to convey information about their sex, reproductive state, and social status. These complex behavioral displays can include visual, auditory, olfactory, tactile, and hydrodynamic signals, and the relative role of each sensory channel in these complex multi-sensory interactions is a common focus of neuroethology. The mechanosensory lateral line system of fishes detects near-body water movements and is implicated in a variety of behaviors including schooling, rheotaxis, social communication, and prey detection. Cobalt chloride is commonly used to chemically ablate lateral line neuromasts, thereby eliminating water-movement cues to test for mechanosensory-mediated behavioral functions. However, cobalt acts as a nonspecific calcium channel antagonist and could potentially disrupt function of all superficially located sensory receptor cells, including those for chemosensing. Here, we examined whether CoCl2 treatment used to ablate the lateral line system also impairs olfaction in three freshwater fishes, the African cichlid fish Astatotilapia burtoni, goldfish Carassius auratus, and the Mexican blind cavefish Astyanax mexicanus. To examine the impact of CoCl2 on the activity of peripheral receptors, we quantified DASPEI fluorescence intensity of the olfactory epithelium from fish exposed to control and CoCl2 solutions. In addition, we examined brain activation in olfactory processing regions of A. burtoni immersed in either control or cobalt solutions. All three species exposed to CoCl2 had decreased DASPEI staining of the olfactory epithelium, and in A. burtoni, cobalt treatment caused reduced neural activation in olfactory processing regions of the brain. To our knowledge this is the first empirical evidence demonstrating that the same CoCl2 treatment used to ablate the lateral line system also impairs olfactory function. These data have important implications for the use of CoCl2 in future

  5. Cobalt Chloride Treatment Used to Ablate the Lateral Line System Also Impairs the Olfactory System in Three Freshwater Fishes.

    PubMed

    Butler, Julie M; Field, Karen E; Maruska, Karen P

    2016-01-01

    Fishes use multimodal signals during both inter- and intra-sexual displays to convey information about their sex, reproductive state, and social status. These complex behavioral displays can include visual, auditory, olfactory, tactile, and hydrodynamic signals, and the relative role of each sensory channel in these complex multi-sensory interactions is a common focus of neuroethology. The mechanosensory lateral line system of fishes detects near-body water movements and is implicated in a variety of behaviors including schooling, rheotaxis, social communication, and prey detection. Cobalt chloride is commonly used to chemically ablate lateral line neuromasts, thereby eliminating water-movement cues to test for mechanosensory-mediated behavioral functions. However, cobalt acts as a nonspecific calcium channel antagonist and could potentially disrupt function of all superficially located sensory receptor cells, including those for chemosensing. Here, we examined whether CoCl2 treatment used to ablate the lateral line system also impairs olfaction in three freshwater fishes, the African cichlid fish Astatotilapia burtoni, goldfish Carassius auratus, and the Mexican blind cavefish Astyanax mexicanus. To examine the impact of CoCl2 on the activity of peripheral receptors, we quantified DASPEI fluorescence intensity of the olfactory epithelium from fish exposed to control and CoCl2 solutions. In addition, we examined brain activation in olfactory processing regions of A. burtoni immersed in either control or cobalt solutions. All three species exposed to CoCl2 had decreased DASPEI staining of the olfactory epithelium, and in A. burtoni, cobalt treatment caused reduced neural activation in olfactory processing regions of the brain. To our knowledge this is the first empirical evidence demonstrating that the same CoCl2 treatment used to ablate the lateral line system also impairs olfactory function. These data have important implications for the use of CoCl2 in future

  6. First DNA Barcode Reference Library for the Identification of South American Freshwater Fish from the Lower Paraná River.

    PubMed

    Díaz, Juan; Villanova, Gabriela Vanina; Brancolini, Florencia; Del Pazo, Felipe; Posner, Victoria Maria; Grimberg, Alexis; Arranz, Silvia Eda

    2016-01-01

    Valid fish species identification is essential for biodiversity conservation and fisheries management. Here, we provide a sequence reference library based on mitochondrial cytochrome c oxidase subunit I for a valid identification of 79 freshwater fish species from the Lower Paraná River. Neighbour-joining analysis based on K2P genetic distances formed non-overlapping clusters for almost all species with a ≥99% bootstrap support each. Identification was successful for 97.8% of species as the minimum genetic distance to the nearest neighbour exceeded the maximum intraspecific distance in all these cases. A barcoding gap of 2.5% was apparent for the whole data set with the exception of four cases. Within-species distances ranged from 0.00% to 7.59%, while interspecific distances varied between 4.06% and 19.98%, without considering Odontesthes species with a minimum genetic distance of 0%. Sequence library validation was performed by applying BOLDs BIN analysis tool, Poisson Tree Processes model and Automatic Barcode Gap Discovery, along with a reliable taxonomic assignment by experts. Exhaustive revision of vouchers was performed when a conflicting assignment was detected after sequence analysis and BIN discordance evaluation. Thus, the sequence library presented here can be confidently used as a benchmark for identification of half of the fish species recorded for the Lower Paraná River. PMID:27442116

  7. Evaluation of a polyclonal antibody for the detection and identification of ranaviruses from freshwater fish and amphibians.

    PubMed

    Cinkova, Katerina; Reschova, Stanislava; Kulich, Pavel; Vesely, Tomas

    2010-04-01

    A rabbit polyclonal antibody (PAb) raised against European catfish virus (ECV; isolated from black bullhead Ameiurus melas in France) was produced and then evaluated using a panel of 9 ranavirus isolates collected from different lower vertebrate species originating from Australia, North and South America, Southeast Asia, and Europe. Using ranavirus-infected epithelioma papillosum cyprini (EPC) cell cultures, the specificity of the PAb was determined by Western blot, immunogold electron microscopy, and direct enzyme-linked immunosorbent assay (ELISA). Western blot analysis demonstrated that the PAb reacted strongly with a protein with a molecular weight corresponding to approximately 49 kDa. Immunogold electron microscopy provided direct evidence that the epitopes recognized by this PAb were located on the outer surface of virions. The PAb was used for the preparation of a peroxidase-labeled conjugate for the direct ELISA detection of ranaviruses in infected EPC cell cultures. The specificity of the conjugated PAb was tested using ranaviruses, some representative fish viruses of the genera Rhabdovirus and Birnavirus, and samples from various non-infected fish species. The PAb detected all tested ranaviruses except for 2 Santee-Cooper ranaviruses. The direct ELISA enabled the detection of ranavirus from a concentration of 10(3.5) to 10(3.8) TCID50 ml(-1) cell culture. The results of this study revealed that the rabbit PAb raised against ECV could be useful for the development of specific and standardized diagnostic assays for the detection of ranaviruses from freshwater fish and amphibians. PMID:20481086

  8. First DNA Barcode Reference Library for the Identification of South American Freshwater Fish from the Lower Paraná River

    PubMed Central

    Brancolini, Florencia; del Pazo, Felipe; Posner, Victoria Maria; Grimberg, Alexis; Arranz, Silvia Eda

    2016-01-01

    Valid fish species identification is essential for biodiversity conservation and fisheries management. Here, we provide a sequence reference library based on mitochondrial cytochrome c oxidase subunit I for a valid identification of 79 freshwater fish species from the Lower Paraná River. Neighbour-joining analysis based on K2P genetic distances formed non-overlapping clusters for almost all species with a ≥99% bootstrap support each. Identification was successful for 97.8% of species as the minimum genetic distance to the nearest neighbour exceeded the maximum intraspecific distance in all these cases. A barcoding gap of 2.5% was apparent for the whole data set with the exception of four cases. Within-species distances ranged from 0.00% to 7.59%, while interspecific distances varied between 4.06% and 19.98%, without considering Odontesthes species with a minimum genetic distance of 0%. Sequence library validation was performed by applying BOLDs BIN analysis tool, Poisson Tree Processes model and Automatic Barcode Gap Discovery, along with a reliable taxonomic assignment by experts. Exhaustive revision of vouchers was performed when a conflicting assignment was detected after sequence analysis and BIN discordance evaluation. Thus, the sequence library presented here can be confidently used as a benchmark for identification of half of the fish species recorded for the Lower Paraná River. PMID:27442116

  9. Levels, Distribution, and Health Risks of Polycyclic Aromatic Hydrocarbons in Four Freshwater Edible Fish Species from the Beijing Market

    PubMed Central

    Wu, Wen-Jing; Qin, Ning; He, Wei; He, Qi-Shuang; Ouyang, Hui-Ling; Xu, Fu-Liu

    2012-01-01

    We first estimated the content of polycyclic aromatic hydrocarbons (PAHs) in the brain, liver, bladder, roe, and muscle of four species of edible freshwater fish from the Beijing market. The distribution characteristics of PAHs in these tissues and organs were analyzed to determine their health risks to humans. The results showed that the residual levels of wet weight and lipid-normalized weight ∑PAHs in various tissues of these fish ranged from 0.51 ng·g−1 to 28.78 ng·g−1 and from 93.62 ng·g−1 to 8203.43 ng·g−1, respectively. The wet weight contents of ∑PAHs were relatively higher in the brain and lower in the liver and muscle. But the differences were not significant. And the differences of lipid-normalized weight PAHs were significant, which in the bighead carp were found significantly the highest, followed in crucian carp, and the lowest in grass carp and carp. The contents of ∑PAHs were the highest in the liver and the lowest in the brain. In the tissues with a higher lipid content, higher residual levels of PAHs were found. The carcinogenic risks for humans from residual ∑PAHs in the various fish tissues were far below 10−5. PMID:23365511

  10. Investigation of bioaccumulation and biotransformation of polybrominated diphenyl ethers, hydroxylated and methoxylated derivatives in varying trophic level freshwater fishes.

    PubMed

    Kim, Un-Jung; Jo, Hyunbin; Lee, In-Seok; Joo, Gea-Jae; Oh, Jeong-Eun

    2015-10-01

    The concentrations and distributions of polybrominated diphenyl ethers (PBDEs) and their hydroxylated and methoxylated derivatives (OH- and MeO-BDEs) were determined in seven representative fish species from a river in the Republic of Korea. The PBDEs and their derivatives were found to be accumulated in the internal organs of the fish to different extents. PBDEs were preferentially accumulated in the internal organs rather than muscle tissue, and especially, showed increasing accumulation tendencies with increasing bromination level in liver. The OH-BDEs and MeO-BDEs were preferentially accumulated in the liver and gastrointestinal tract, respectively. MeO-BDE concentrations were found to increase according to relative trophic level, suggesting that the PBDE derivatives can be biomagnified to a greater extent than the parent PBDEs in freshwater food webs. In a comparison with the dissolved analyte concentrations in the water that were measured by using semi-permeable membrane devices, the greater uptake of non-ortho substituted MeO-BDEs by fish was observed. PMID:26092317

  11. Discovering hidden biodiversity: the use of complementary monitoring of fish diet based on DNA barcoding in freshwater ecosystems.

    PubMed

    Jo, Hyunbin; Ventura, Marc; Vidal, Nicolas; Gim, Jeong-Soo; Buchaca, Teresa; Barmuta, Leon A; Jeppesen, Erik; Joo, Gea-Jae

    2016-01-01

    Ecological monitoring contributes to the understanding of complex ecosystem functions. The diets of fish reflect the surrounding environment and habitats and may, therefore, act as useful integrating indicators of environmental status. It is, however, often difficult to visually identify items in gut contents to species level due to digestion of soft-bodied prey beyond visual recognition, but new tools rendering this possible are now becoming available. We used a molecular approach to determine the species identities of consumed diet items of an introduced generalist feeder, brown trout (Salmo trutta), in 10 Tasmanian lakes and compared the results with those obtained from visual quantification of stomach contents. We obtained 44 unique taxa (OTUs) belonging to five phyla, including seven classes, using the barcode of life approach from cytochrome oxidase I (COI). Compared with visual quantification, DNA analysis showed greater accuracy, yielding a 1.4-fold higher number of OTUs. Rarefaction curve analysis showed saturation of visually inspected taxa, while the curves from the DNA barcode did not saturate. The OTUs with the highest proportions of haplotypes were the families of terrestrial insects Formicidae, Chrysomelidae, and Torbidae and the freshwater Chironomidae. Haplotype occurrence per lake was negatively correlated with lake depth and transparency. Nearly all haplotypes were only found in one fish gut from a single lake. Our results indicate that DNA barcoding of fish diets is a useful and complementary method for discovering hidden biodiversity. PMID:26811787

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

    PubMed Central

    Pollom, Riley A.; Rose, George A.

    2015-01-01

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

  13. Handbook of Techniques and Guides for the Study of the San Francisco Bay-Delta-Estuary Complex, Part 5. Keys to the Freshwater and Anadromous Fishes of California.

    ERIC Educational Resources Information Center

    Kimsey, J. B.; Fisk, Leonard O.

    1960-01-01

    This key to freshwater and anadromous fishes of California is included as the fifth of a series of guides being produced by Project MER (Marine Ecology Research). This project is part of the effort to improve environmental education in the San Francisco Bay Area schools by gathering and organizing data on the ecological character of the San…

  14. Validation and Extension of a Rapid Method of Dioxin Screening in Marine and Freshwater Fish through Multivariate Statistical Analysis of Fatty Acid Profiles

    EPA Science Inventory

    Over 95% of human exposure to dioxin is through ingestion of animal fats. Studies have identified both freshwater and marine fish, from wild and farmed stocks, as a significant source of human exposure to dioxins (Alcock and others 1998; Turyk and others, in press; Rawn and othe...

  15. Allozyme genotype in mosquitofish, Gambusia holbrooki, during mercury exposure: Temporal stability, concentration effects and field verification

    SciTech Connect

    Heagler, M.G. Rutgers, The State Univ. of New Jersey, New Brunswick )

    1993-02-01

    Genotype frequencies at nine enzyme loci were examined in a population of mosquito fish, Gambusia holbrooki, during acute inorganic mercury exposure at three concentration. Genotype at one locus, glucose phosphate isomerase-2 (Gpi-2), was correlated with time to death (TTD) at the low mercury concentration, but genotypes at none of the nine loci were related to TTD at the medium or the high mercury concentration. A survey of mosquitofish from a mercury-contaminated canal was undertaken to determine if the results of laboratory exposures could be used to predict accurately the genetic profile of mercury-contaminated field populations. Mosquitofish collected from the contaminated canal had a significantly lower frequency of the Gpi-2[sup 38] allele than mosquitofish collected from the adjacent noncontaminated river. The Gpi-2 allozymes may be useful as an indicator of pollutant stress if used in conjunction with a thorough understanding of the structure and history of the population.

  16. A new species of Dactylogyrus (Monogenea: Dactylogyridae) parasitic on an endangered freshwater fish, Rhodeus atremius atremius, endemic to Japan.

    PubMed

    Nitta, Masato; Nagasawa, Kazuya

    2016-10-01

    A new dactylogyrid monogenean Dactylogyrus bicorniculus sp. nov. is described from the gills of the kazetoge bitterling, Rhodeus atremius atremius (Jordan and Thompson, 1914), an endemic species in Japan, from Saga Prefecture, northern Kyūshū. D. bicorniculus sp. nov. resembles Dactylogyrus bicornis Malevitskaja, 1941 and Dactylogyrus lophogonus Zhang and Ji, 1980 because they have two common features, a large V-shaped ventral bar and well-developed second marginal hooks. However, the new species is distinguished from these congeners by a shorter penis and an accessory piece. A phylogenetic analysis of 28S rDNA shows that D. bicorniculus sp. nov. is a basal species with the T-shaped ventral bar in the genus. The new species has strict host-specificity to R. a. atremius, one of the endangered freshwater fishes in Japan, and may face the danger of co-extinction with its host. PMID:27377236

  17. Automatic underwater radiotelemetry system to monitor temperature responses of fish in a freshwater environment

    SciTech Connect

    Prepejchal, W.; Thommes, M.M.; Spigarelli, S.A.; Haumann, J.R.; Hess, P.E.

    1980-11-01

    An automated radiotelemetry system developed to monitor body and water temperature of free-swimming fish is described. The receiving and data acquisition unit can be programmed to monitor as many as 16 transmitters (fish); each transmitter can time-multiply data from up to 9 resistive transducers. A typical transmitter with saddle-type attachment, suitable for fish weighing 1 to over 10 kg, has a submerged weight of less than 10 g. The typical range is 2700 m for fish 1 m below the surface. Complete schematics and operational logic are provided for the receiver and data processing printed circuit boards, for 3 types of fish transmitters, and for an environmental parameter monitor. Construction methods, calibration and tagging procedures, and the required computer programs are detailed. This system was in operation for 3 years at the Point Beach Nuclear Power Plant, Two Creeks, Wisconsin. Of the 89 fish tagged, 77 fish provided useable body and water temperature information with tracking times ranging from 0.5 to 505 hours. Modifications which would further improve the system's reliability are discussed.

  18. Host tropism of infectious salmon anaemia virus in marine and freshwater fish species.

    PubMed

    Aamelfot, M; Dale, O B; McBeath, A; Falk, K

    2015-08-01

    The aquatic orthomyxovirus infectious salmon anaemia virus (ISAV) causes a severe disease in farmed Atlantic salmon, Salmo salar L. Although some ISA outbreaks are caused by horizontal transmission of virus between farms, the source and reservoir of the virus is largely unknown and a wild host has been hypothesized. Atlantic salmon are farmed in open net-pens, allowing transmission of pathogens from wild fish and the surrounding environment to the farmed fish. In this study, a large number of fish species were investigated for ISAV host potential. For orthomyxoviruses, a specific receptor binding is the first requirement for infection; thus, the fish species were investigated for the presence of the ISAV receptor. The receptor was found to be widely distributed across the fish species. All salmonids expressed the receptor. However, only some of the cod-like and perch-like fish did, and all flat fish were negative. In the majority of the positive species, the receptor was found on endothelial cells and/or on red blood cells. The study forms a basis for further investigations and opens up the possibility for screening species to determine whether a wild host of ISAV exists. PMID:25048819

  19. Physiological response of some economically important freshwater salmonids to catch-and-release fishing

    USGS Publications Warehouse

    Wedemeyer, G.A.; Wydoski, R.S.

    2008-01-01

    Catch-and-release fishing regulations are widely used by fishery resource managers to maintain both the quantity and quality of sport fish populations. We evaluated blood chemistry disturbances in wild brook trout Salvelinus fontinalis, brown trout Salmo trutta, cutthroat trout Oncorhynchus clarkii, and Arctic grayling Thymallus arcticus that had been hooked and played for 1-5 min in waters of the intermountain western United States. A hatchery stock of brown trout was included for comparison. To assess time needed for recovery, additional test groups were played for 5 min and then released into net-pens, where they were held for up to 72 h. The osmoregulatory and metabolic disturbances associated with catch-and-release fishing under the conditions we tested were minimal and judged to be well within normal physiological tolerance limits. In fish that were held for recovery, the blood chemistry alterations that did occur appeared to be related to stress from confinement in the net-pens. Our results confirm the results of previous studies, showing that prerelease air exposure and handling cause more physiological stress than does either hooking per se or playing time. Fishery managers must be aware of the differences in the perceptions, attitudes, and values of different societal groups, some of which feel that catch-and-release fishing should be banned because it is cruel to the animals. On the basis of brain anatomy, it seems highly unlikely that fish experience pain in the same manner as humans experience it, because fish lack a neocortex, the brain structure that enables the sensation of pain in higher vertebrates. However, independent of the neurobiological argument, our results indicate that under conditions similar to those tested, fish subjected to catch and release are neither suffering nor particularly stressed. Improved education programs about the relatively benign physiological effects of catch-and-release fishing as a fishery management practice would

  20. Modeling seasonal dynamics of the small fish cohorts in fluctuating freshwater marsh landscapes

    USGS Publications Warehouse

    Jopp, Fred; DeAngelis, Donald L.; Trexler, Joel C.

    2010-01-01

    Small-bodied fishes constitute an important assemblage in many wetlands. In wetlands that dry periodically except for small permanent waterbodies, these fishes are quick to respond to change and can undergo large fluctuations in numbers and biomasses. An important aspect of landscapes that are mixtures of marsh and permanent waterbodies is that high rates of biomass production occur in the marshes during flooding phases, while the permanent waterbodies serve as refuges for many biotic components during the dry phases. The temporal and spatial dynamics of the small fishes are ecologically important, as these fishes provide a crucial food base for higher trophic levels, such as wading birds. We develop a simple model that is analytically tractable, describing the main processes of the spatio-temporal dynamics of a population of small-bodied fish in a seasonal wetland environment, consisting of marsh and permanent waterbodies. The population expands into newly flooded areas during the wet season and contracts during declining water levels in the dry season. If the marsh dries completely during these times (a drydown), the fish need refuge in permanent waterbodies. At least three new and general conclusions arise from the model: (1) there is an optimal rate at which fish should expand into a newly flooding area to maximize population production; (2) there is also a fluctuation amplitude of water level that maximizes fish production, and (3) there is an upper limit on the number of fish that can reach a permanent waterbody during a drydown, no matter how large the marsh surface area is that drains into the waterbody. Because water levels can be manipulated in many wetlands, it is useful to have an understanding of the role of these fluctuations.

  1. Fish predation by semi-aquatic spiders: a global pattern.

    PubMed

    Nyffeler, Martin; Pusey, Bradley J

    2014-01-01

    More than 80 incidences of fish predation by semi-aquatic spiders--observed at the fringes of shallow freshwater streams, rivers, lakes, ponds, swamps, and fens--are reviewed. We provide evidence that fish predation by semi-aquatic spiders is geographically widespread, occurring on all continents except Antarctica. Fish predation by spiders appears to be more common in warmer areas between 40° S and 40° N. The fish captured by spiders, usually ranging from 2-6 cm in length, are among the most common fish taxa occurring in their respective geographic area (e.g., mosquitofish [Gambusia spp.] in the southeastern USA, fish of the order Characiformes in the Neotropics, killifish [Aphyosemion spp.] in Central and West Africa, as well as Australian native fish of the genera Galaxias, Melanotaenia, and Pseudomugil). Naturally occurring fish predation has been witnessed in more than a dozen spider species from the superfamily Lycosoidea (families Pisauridae, Trechaleidae, and Lycosidae), in two species of the superfamily Ctenoidea (family Ctenidae), and in one species of the superfamily Corinnoidea (family Liocranidae). The majority of reports on fish predation by spiders referred to pisaurid spiders of the genera Dolomedes and Nilus (>75% of observed incidences). There is laboratory evidence that spiders from several more families (e.g., the water spider Argyroneta aquatica [Cybaeidae], the intertidal spider Desis marina [Desidae], and the 'swimming' huntsman spider Heteropoda natans [Sparassidae]) predate fish as well. Our finding of such a large diversity of spider families being engaged in fish predation is novel. Semi-aquatic spiders captured fish whose body length exceeded the spiders' body length (the captured fish being, on average, 2.2 times as long as the spiders). Evidence suggests that fish prey might be an occasional prey item of substantial nutritional importance. PMID:24940885

  2. Fish Predation by Semi-Aquatic Spiders: A Global Pattern

    PubMed Central

    Nyffeler, Martin; Pusey, Bradley J.

    2014-01-01

    More than 80 incidences of fish predation by semi-aquatic spiders – observed at the fringes of shallow freshwater streams, rivers, lakes, ponds, swamps, and fens – are reviewed. We provide evidence that fish predation by semi-aquatic spiders is geographically widespread, occurring on all continents except Antarctica. Fish predation by spiders appears to be more common in warmer areas between 40° S and 40° N. The fish captured by spiders, usually ranging from 2–6 cm in length, are among the most common fish taxa occurring in their respective geographic area (e.g., mosquitofish [Gambusia spp.] in the southeastern USA, fish of the order Characiformes in the Neotropics, killifish [Aphyosemion spp.] in Central and West Africa, as well as Australian native fish of the genera Galaxias, Melanotaenia, and Pseudomugil). Naturally occurring fish predation has been witnessed in more than a dozen spider species from the superfamily Lycosoidea (families Pisauridae, Trechaleidae, and Lycosidae), in two species of the superfamily Ctenoidea (family Ctenidae), and in one species of the superfamily Corinnoidea (family Liocranidae). The majority of reports on fish predation by spiders referred to pisaurid spiders of the genera Dolomedes and Nilus (>75% of observed incidences). There is laboratory evidence that spiders from several more families (e.g., the water spider Argyroneta aquatica [Cybaeidae], the intertidal spider Desis marina [Desidae], and the ‘swimming’ huntsman spider Heteropoda natans [Sparassidae]) predate fish as well. Our finding of such a large diversity of spider families being engaged in fish predation is novel. Semi-aquatic spiders captured fish whose body length exceeded the spiders’ body length (the captured fish being, on average, 2.2 times as long as the spiders). Evidence suggests that fish prey might be an occasional prey item of substantial nutritional importance. PMID:24940885

  3. Hepatic oxidative stress biomarker responses in freshwater fish Carassius auratus exposed to four benzophenone UV filters.

    PubMed

    Liu, Hui; Sun, Ping; Liu, Hongxia; Yang, Shaogui; Wang, Liansheng; Wang, Zunyao

    2015-09-01

    Benzophenone (BP) type UV filters are widely used in many personal care products to protect human from UV irradiation. Despite the estrogenic potencies to fish and the environmental occurrences of BP derivatives in aquatic systems, little information is available regarding their effects on the antioxidant defense system in fish. In this work, the oxidative stress induced in livers of Carassius auratus was assessed using four biomarkers. The integrated biomarker response (IBR) was applied to assess the overall antioxidant status in fish. Moreover, liver tissues were also studied histologically. The changes in the activities of antioxidant enzymes and glutathione levels suggested that BPs generates oxidative stress in fish. The IBR index revealed that the hepatic oxidative toxicity followed the order BP-1>BP-2>BP-4>BP-3. The histopathological analysis revealed lesions caused by BPs. This investigation provides essential information for assessing the potential ecological risk of BP-type UV filters. PMID:25996523

  4. Bioaccumulation and ROS generation in liver of freshwater fish, goldfish Carassius auratus under HC Orange No 1 exposure.

    PubMed

    Sun, Yuanyuan; Yin, Ying; Zhang, Jingfei; Yu, Hongxia; Wang, Xiaorong

    2007-06-01

    HC Orange No. 1 (CAS No. 54381-08-7, 2-nitro-4'-hydroxydiphenylamine) is used as a color additive in hair dyes. In this study, laboratory experiment was carried out to determine HC Orange No. 1 bioaccumulation and oxidative stress in the liver of freshwater fish, goldfish Carassius auratus. Fish were exposed to different concentrations (0.05, 0.1, 0.2, 0.5, and 1.0 mg/L) of HC Orange No. 1 for 10 days, with one group assigned as control. The accumulation of HC Orange No. 1 in liver increased with the exposure concentration (R(2) = 0.94). A secondary spin trapping technique was used followed by electron paramagnetic resonance (EPR) analysis to study the reactive oxygen species (ROS) production. On the basis of the hyperfine splitting constants and shape of the EPR spectrum, the ROS generated in fish liver after exposure was identified as hydroxyl radical (*OH). There is a good correlation between the exposure concentrations and *OH generation (R(2) = 0.92). The *OH signal intensity of the EPR spectrum showed a significant increase (P < 0.05) when the HC Orange No. 1 concentration was 1.0 mg/L, compared with that of the control. A good positive relationship (R(2) = 0.95) was found between the *OH formation and accumulation level of HC Orange No. 1 in liver. The changes of the activities of catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), and contents of reduced glutathione (GSH) were also detected. These observations indicated a possible mechanism of oxidative stress induced by HC Orange No. 1 on fish. PMID:17497642

  5. Understanding behavioral responses of fish to pheromones in natural freshwater environments

    USGS Publications Warehouse

    Johnson, Nicholas S.; Li, Weiming

    2010-01-01

    There is an abundance of experimental studies and reviews that describe odorant-mediated behaviors of fish in laboratory microcosms, but research in natural field conditions has received considerably less attention. Fish pheromone studies in laboratory settings can be highly productive and allow for controlled experimental designs; however, laboratory tanks and flumes often cannot replicate all the physical, physiological and social contexts associated with natural environments. Field experiments can be a critical step in affirming and enhancing understanding of laboratory discoveries and often implicate the ecological significance of pheromones employed by fishes. When findings from laboratory experiments have been further tested in field environments, often different and sometimes contradictory conclusions are found. Examples include studies of sea lamprey (Petromyzon marinus) mating pheromones and fish alarm substances. Here, we review field research conducted on fish pheromones and alarm substances, highlighting the following topics: (1) contradictory results obtained in laboratory and field experiments, (2) how environmental context and physiological status influences behavior, (3) challenges and constraints of aquatic field research and (4) innovative techniques and experimental designs that advance understanding of fish chemical ecology through field research.

  6. Rapidly shifting maturation schedules following reduced commercial harvest in a freshwater fish

    PubMed Central

    Feiner, Zachary S; Chong, Stephen C; Knight, Carey T; Lauer, Thomas E; Thomas, Michael V; Tyson, Jeffrey T; Höök, Tomas O

    2015-01-01

    Size-selective harvest of fish stocks can lead to maturation at smaller sizes and younger ages, which may depress stock productivity and recovery. Such changes in maturation may be very slow to reverse, even following complete fisheries closures. We evaluated temporal trends in maturation of five Great Lakes stocks of yellow perch (Perca flavescens Mitchill) using indices that attempt to disentangle plastic and evolutionary changes in maturation: age at 50% maturity and probabilistic maturation reaction norms (PMRNs). Four populations were fished commercially throughout the time series, while the Lake Michigan fishery was closed following a stock collapse. We documented rapid increases in PMRNs of the Lake Michigan stock coincident with the commercial fishery closure. Saginaw Bay and Lake Huron PMRNs also increased following reduced harvest, while Lake Erie populations were continuously fished and showed little change. The rapid response of maturation may have been enhanced by the short generation time of yellow perch and potential gene flow between northern and southern Lake Michigan, in addition to potential reverse adaptation following the fishing moratorium. These results suggest that some fish stocks may retain the ability to recover from fisheries-induced life history shifts following fishing moratoria. PMID:26240608

  7. The gut microbiome and degradation enzyme activity of wild freshwater fishes influenced by their trophic levels

    PubMed Central

    Liu, Han; Guo, Xianwu; Gooneratne, Ravi; Lai, Ruifang; Zeng, Cong; Zhan, Fanbin; Wang, Weimin

    2016-01-01

    Vertebrate gut microbiome often underpins the metabolic capability and provides many beneficial effects on their hosts. However, little was known about how host trophic level influences fish gut microbiota and metabolic activity. In this study, more than 985,000 quality-filtered sequences from 24 16S rRNA libraries were obtained and the results revealed distinct compositions and diversities of gut microbiota in four trophic categories. PCoA test showed that gut bacterial communities of carnivorous and herbivorous fishes formed distinctly different clusters in PCoA space. Although fish in different trophic levels shared a large size of OTUs comprising a core microbiota community, at the genus level a strong distinction existed. Cellulose-degrading bacteria Clostridium, Citrobacter and Leptotrichia were dominant in the herbivorous, while Cetobacterium and protease-producing bacteria Halomonas were dominant in the carnivorous. PICRUSt predictions of metagenome function revealed that fishes in different trophic levels affected the metabolic capacity of their gut microbiota. Moreover, cellulase and amylase activities in herbivorous fishes were significantly higher than in the carnivorous, while trypsin activity in the carnivorous was much higher than in the herbivorous. These results indicated that host trophic level influenced the structure and composition of gut microbiota, metabolic capacity and gut content enzyme activity. PMID:27072196

  8. The gut microbiome and degradation enzyme activity of wild freshwater fishes influenced by their trophic levels.

    PubMed

    Liu, Han; Guo, Xianwu; Gooneratne, Ravi; Lai, Ruifang; Zeng, Cong; Zhan, Fanbin; Wang, Weimin

    2016-01-01

    Vertebrate gut microbiome often underpins the metabolic capability and provides many beneficial effects on their hosts. However, little was known about how host trophic level influences fish gut microbiota and metabolic activity. In this study, more than 985,000 quality-filtered sequences from 24 16S rRNA libraries were obtained and the results revealed distinct compositions and diversities of gut microbiota in four trophic categories. PCoA test showed that gut bacterial communities of carnivorous and herbivorous fishes formed distinctly different clusters in PCoA space. Although fish in different trophic levels shared a large size of OTUs comprising a core microbiota community, at the genus level a strong distinction existed. Cellulose-degrading bacteria Clostridium, Citrobacter and Leptotrichia were dominant in the herbivorous, while Cetobacterium and protease-producing bacteria Halomonas were dominant in the carnivorous. PICRUSt predictions of metagenome function revealed that fishes in different trophic levels affected the metabolic capacity of their gut microbiota. Moreover, cellulase and amylase activities in herbivorous fishes were significantly higher than in the carnivorous, while trypsin activity in the carnivorous was much higher than in the herbivorous. These results indicated that host trophic level influenced the structure and composition of gut microbiota, metabolic capacity and gut content enzyme activity. PMID:27072196

  9. Mechanisms of maintenance of tropical freshwater fish communities in the face of disturbance.

    PubMed

    Martin-Smith, K M; Laird, L M; Bullough, L; Lewis, M G

    1999-11-29

    Community resistance to, and resilience from, perturbation will determine the trajectory of recovery from disturbance. Although selective timber extraction is considered a severe disturbance, fish communities from headwater streams around Danum Valley Field Centre, Sabah, Malaysia, showed few long-term changes in species composition or abundance. However, some species showed short-term (< 18 months) absence or decrease in abundance. These observations suggested that both resistance and resilience were important in maintaining long-term fish community structure. Resistance to perturbation was tested by monitoring fish communities before and after the creation of log-debris dams, while resilience was investigated by following the time-course of recolonization following complete removal of all fish. High community resistance was generally shown although the response was site-specific, dependent on the composition of the starting community, the size of the stream and physical habitat changes. High resilience was demonstrated in all recolonization experiments with strong correlations between pre- and post-defaunation communities, although there was a significant difference between pool and riffle habitats in the time-course of recovery. These differences can be explained by the movement characteristics of the species found in the different habitats. Resilience appeared to be a more predictable characteristic of the community than resistance and the implications of this for ensuring the long-term persistence of fish in the area are discussed. PMID:11605623

  10. Myxobolus myleus n. sp. infecting the bile of the Amazonian freshwater fish Myleus rubripinnis (Teleostei: Serrasalmidae): morphology and pathology.

    PubMed

    Azevedo, Carlos; São Clemente, Sérgio Carmona; Casal, Graça; Matos, Patrícia; Alves, Ângela; Al-Quraishy, Saleh; Matos, Edilson

    2012-07-01

    Myxobolus myleus n. sp. is described from the gall-bladder of the freshwater fish Myleus rubripinnis collected near the city of Oriximiná in the Amazon System, Brazil. The spores obtained from the bile contained two equal symmetrical and smooth valves, each forming the spore wall. The spores were large, with a cone-like form, a semi spherical basal contour and measured (in μm) 19.3 ± 0.5 (n = 25) × 8.3 ± 0.5 (n = 25) × 4.0 ± 0.3 (n = 15). The apical end of the spores contained two elongate, equal and pointed conical polar capsules measuring 13.2 ± 0.4 μm (n = 25) in length and 3.0 ± 0.3 μm (n = 15) in width, each having a slightly tapering polar filament with 19 to 21 turns. The polar capsules were extended below at about 4/5 of the total length of the spores. The sporoplasm was binucleate and contained some sporoplasmosomes. All infected fish presented hypertrophy of the gall-bladder due to presence of the brownish parasite floating in the bile. In this paper we describe this new species of myxosporean based on light and ultrastructural observations, together with its associated pathology. PMID:22711511

  11. Hepatoprotective activity of Tribulus terrestris extract against acetaminophen-induced toxicity in a freshwater fish (Oreochromis mossambicus).

    PubMed

    Kavitha, P; Ramesh, R; Bupesh, G; Stalin, A; Subramanian, P

    2011-12-01

    The potential protective role of Tribulus terrestris in acetaminophen-induced hepatotoxicity in Oreochromis mossambicus was investigated. The effect of oral exposure of acetaminophen (500 mg/kg) in O. mossambicus at 24-h duration was evaluated. The plant extract (250 mg/kg) showed a remarkable hepatoprotective activity against acetaminophen-induced hepatotoxicity. It was judged from the tissue-damaging level and antioxidant levels in liver, gill, muscle and kidney tissues. Further acetaminophen impact induced a significant rise in the tissue-damaging level, and the antioxidant level was discernible from the enzyme activity modulations such as glutamate oxaloacetic transaminase, glutamate pyruvic transaminase, alkaline phosphatase, acid phosphatase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase, lipid peroxidase and reduced glutathione. The levels of all these enzymes have significantly (p < 0.05) increased in acetaminophen-treated fish tissues. The elevated levels of these enzymes were significantly controlled by the treatment of T. terrestris extract (250 kg/mg). Histopathological changes of liver, gill and muscle samples were compared with respective controls. The results of the present study specify the hepatoprotective and antioxidant properties of T. terrestris against acetaminophen-induced toxicity in freshwater fish, O. mossambicus. PMID:21975853

  12. A new model for fish ion regulation: identification of ionocytes in freshwater- and seawater-acclimated medaka (Oryzias latipes).

    PubMed

    Hsu, Hao-Hsuan; Lin, Li-Yih; Tseng, Yung-Che; Horng, Jiun-Lin; Hwang, Pung-Pung

    2014-07-01

    The ion regulation mechanisms of fishes have been recently studied in zebrafish (Danio rerio), a stenohaline species. However, recent advances using this organism are not necessarily applicable to euryhaline fishes. The euryhaline species medaka (Oryzias latipes), which, like zebrafish, is genetically well categorized and amenable to molecular manipulation, was proposed as an alternative model for studying osmoregulation during acclimation to different salinities. To establish its suitability as an alternative, the present study was conducted to (1) identify different types of ionocytes in the embryonic skin and (2) analyze gene expressions of the transporters during seawater acclimation. Double/triple in situ hybridization and/or immunocytochemistry revealed that freshwater (FW) medaka contain three types of ionocyte: (1) Na(+)/H(+) exchanger 3 (NHE3) cells with apical NHE3 and basolateral Na(+)-K(+)-2Cl(-) cotransporter (NKCC), Na(+)-K(+)-ATPase (NKA) and anion exchanger (AE); (2) Na(+)-Cl(-) cotransporter (NCC) cells with apical NCC and basolateral H(+)-ATPase; and (3) epithelial Ca(2+) channel (ECaC) cells [presumed accessory (AC) cells] with apical ECaC. On the other hand, seawater (SW) medaka has a single predominant ionocyte type, which possesses apical cystic fibrosis transmembrane conductance regulator (CFTR) and NHE3 and basolateral NKCC and NKA and is accompanied by smaller AC cells that express lower levels of basolateral NKA. Reciprocal gene expressions of decreased NHE3, AE, NCC and ECaC and increased CFTR and NKCC in medaka gills during SW were revealed by quantative PCR analysis. PMID:24842048

  13. Size-selective feeding on phytoplankton by two morpho-groups of the small freshwater fish Amblypharyngodon mola.

    PubMed

    Nandi, S; Saikia, S K

    2015-08-01

    Two morpho-groups (i.e., small, MGS and big, MGL) of the small freshwater fish Amblypharyngodon mola were studied for their feeding behaviour in the natural environment. Both the morpho-groups fed on a variety of phytoplankton including Cyanophyceae, Chlorophyceae, Bacillariophyceae and Euglenophyceae. The fish had more Chlorophyceae and Bacillariophyceae in their gut than other phytoplankton. Costello's selectivity plots revealed that the MGS fed on the smaller phytoplankters (2-6 µm in size), whereas the MGL fed on both the small and large (up to 12 µm in size) phytoplankters. The differences in mouth areas between the two morpho-groups were explained as a possible reason of size-selective feeding and contribute to overcome gape limitation in A. mola. This is further accompanied by the uniform pore size of the gills (2 µm) in all the morpho-groups. This study concluded that A. mola exhibits a size-dependent feeding strategy regulated by gape limitation at the ingestion level. With ontogenetic shifts, flexibility appears to overcome such a limitation in the MGL, having a wider mouth area supported by jaw opening ability. PMID:26084383

  14. Responses of antioxidant defense system to polyfluorinated dibenzo-p-dioxins (PFDDs) exposure in liver of freshwater fish Carassius auratus.

    PubMed

    Li, Chenguang; Qin, Li; Qu, Ruijuan; Sun, Ping; Wang, Zunyao

    2016-04-01

    In this study, we evaluated the toxicity of ten polyfluorinated dibenzo-p-dioxins (PFDDs) congeners to freshwater fish Carassius auratus, by determining the antioxidative responses and lipid peroxidation in the liver after the fish were injected with two different concentrations (10 and 100 µmol/kg) of individual PFDDs for 3 and 14 days. The results showed that oxidative stress was obviously induced in some PFDDs-treated groups, as implied by the significantly inhibited antioxidants levels (superoxide dismutase, catalase, reduced glutathione, and glutathione S-transferase) and elevated malondialdehyde content. In addition, the oxidative stress inducing ability was variable for different PFDDs congeners, which was related with the substitution number and position of fluorine atom. Based on the calculated integrated biomarker response (IBR) values, the toxicity was ranked as 2,3,7,8-FDD>Octa-FDD>1,2,3,4,7-FDD>1,3,6,8-FDD>1,2,3,4,6,7-FDD>1,2,6,7-FDD>1,2,7-FDD>DD>2,7-FDD>2-FDD. This study can enhance the general understanding of the PFDDs induced oxidative stress in aquatic organisms. PMID:26761781

  15. Application of sulphur isotope ratios to examine weaning patterns and freshwater fish consumption in Roman Oxfordshire, UK

    NASA Astrophysics Data System (ADS)

    Nehlich, Olaf; Fuller, Benjamin T.; Jay, Mandy; Mora, Alice; Nicholson, Rebecca A.; Smith, Colin I.; Richards, Michael P.

    2011-09-01

    This study investigates the application of sulphur isotope ratios (δ 34S) in combination with carbon (δ 13C) and nitrogen (δ 15N) ratios to understand the influence of environmental sulphur on the isotopic composition of archaeological human and faunal remains from Roman era sites in Oxfordshire, UK. Humans ( n = 83), terrestrial animals ( n = 11), and freshwater fish ( n = 5) were analysed for their isotope values from four locations in the Thames River Valley, and a broad range of δ 34S values were found. The δ 34S values from the terrestrial animals were highly variable (-13.6‰ to +0.5‰), but the δ 34S values of the fish were clustered and 34S-depleted (-20.9‰ to -17.3‰). The results of the faunal remains suggest that riverine sulphur influenced the terrestrial sulphur isotopic signatures. Terrestrial animals were possibly raised on the floodplains of the River Thames, where highly 34S-depleted sulphur influenced the soil. The humans show the largest range of δ 34S values (-18.8‰ to +9.6‰) from any archaeological context to date. No differences in δ 34S values were found between the males (-7.8 ± 6.0‰) and females (-5.3 ± 6.8‰), but the females had a linear correlation ( R2 = 0.71; p < 0.0001) between their δ 15N and δ 34S compositions. These δ 34S results suggest a greater dietary variability for the inhabitants of Roman Oxfordshire than previously thought, with some individuals eating solely terrestrial protein resources and others showing a diet almost exclusively based on freshwater protein such as fish. Such large dietary variability was not visible by analysing only the carbon and nitrogen isotope ratios, and this research represents the largest and most detailed application of δ 34S analysis to examine dietary practices (including breastfeeding and weaning patterns) during the Romano-British Period.

  16. Evolutionary history of Otophysi (Teleostei), a major clade of the modern freshwater fishes: Pangaean origin and Mesozoic radiation

    PubMed Central

    2011-01-01

    Background Freshwater harbors approximately 12,000 fish species accounting for 43% of the diversity of all modern fish. A single ancestral lineage evolved into about two-thirds of this enormous biodiversity (≈ 7900 spp.) and is currently distributed throughout the world's continents except Antarctica. Despite such remarkable species diversity and ubiquity, the evolutionary history of this major freshwater fish clade, Otophysi, remains largely unexplored. To gain insight into the history of otophysan diversification, we constructed a timetree based on whole mitogenome sequences across 110 species representing 55 of the 64 families. Results Partitioned maximum likelihood analysis based on unambiguously aligned sequences (9923 bp) confidently recovered the monophyly of Otophysi and the two constituent subgroups (Cypriniformes and Characiphysi). The latter clade comprised three orders (Gymnotiformes, Characiformes, Siluriformes), and Gymnotiformes was sister to the latter two groups. One of the two suborders in Characiformes (Characoidei) was more closely related to Siluriformes than to its own suborder (Citharinoidei), rendering the characiforms paraphyletic. Although this novel relationship did not receive strong statistical support, it was supported by analyzing independent nuclear markers. A relaxed molecular clock Bayesian analysis of the divergence times and reconstruction of ancestral habitats on the timetree suggest a Pangaean origin and Mesozoic radiation of otophysans. Conclusions The present timetree demonstrates that survival of the ancestral lineages through the two consecutive mass extinctions on Pangaea, and subsequent radiations during the Jurassic through early Cretaceous shaped the modern familial diversity of otophysans. This evolutionary scenario is consistent with recent arguments based on biogeographic inferences and molecular divergence time estimates. No fossil otophysan, however, has been recorded before the Albian, the early Cretaceous 100

  17. National contaminant biomonitoring program: rEesidues of organochlorine chemicals in U.S. Freshwater Fish, 1976–1984

    USGS Publications Warehouse

    Schmitt, Christopher J.; Zajicek, Jim L.; Peterman, Paul H.

    1990-01-01

    The U.S. Fish and Wildlife Service periodically determines concentrations of organochlorine chemicals in freshwater fish collected from a nationwide network of stations as part of the National Contaminant Biomonitoring Program (NCBP, formerly a part of the National Pesticide Monitoring Program). From late 1984 to early 1985, a total of 321 composite fish samples were collected from 112 stations and analyzed for organochlorine chemical residues. The mean concentrations of total DDT did not change from 1980–81 to 1984, following a period of steady decline through the 1970's; however, the mean concentrations ofp,p′-DDT declined significantly. The most persistent DDT homolog (p,p′-DDE) was detected at 98% of the stations sampled in 1984, and constituted 73% of total DDT residues, up from 70% in 1974–79. Collectively, these findings indicate a low rate of influx and continued weathering of DDT in the environment. Residues of polychlorinated biphenyls (PCBs) also remained widespread, but a significant downward trend in total PCBs was evident, and early eluting PCB components were present at fewer stations than in the past. Mean concentrations of dieldrin have not changed since 1978–79; concentrations remained highest in Hawaii and in the Great Lakes. Toxaphene concentrations declined from 1980–81 to 1984, especially in the Great Lakes, and the incidence of toxaphene declined from 88% of the stations sampled in 1980–81 to 69% in 1984. Mean chordane concentrations did not change from 1980–81 to 1984, following a period of decline; however,trans-nonachlor replacedcis-chlordane as the most abundant component, suggesting a lower influx of chlordane to the aquatic environment. Residues of other organochlorines—mirex, pentachloroanisole (PCA), benzene hexachloride (BHC) isomers, endrin, heptachlor, hexachlorobenzene (HCB), and Dacthal® (DCPA)—were either found at relatively few (<25%) of the stations sampled in 1984 or were characterized by relatively low

  18. Ethyl-p-aminobenzoate (Benzocaine): efficacy as an anesthetic for five species of freshwater fish

    USGS Publications Warehouse

    Dawson, V.K.; Gilderhus, P.A.

    1979-01-01

    Ethyl-p-aminobenzoate (benzocaine) was tested for its efficacy as an anesthetic for rainbow trout (Salmo gairdnerii, brown trout (Salmo truttas, northern pike (Esox lucius). carp (Cyprinus carpio), and largemouth bass (Mieropterus salmoidesi. Since benzocaine is not water soluble, it was applied with acetone as a carrier. Concentrations of 100 to 200 mg!l were required for large adult northern pike, compared with 50 to 100 mg/l for small fish. Rates of sedation and recovery were slower in cold water than in warm water. Water hardness had little influence on the activity of benzocaine. Fish were anesthetized faster and recovered more slowly in acid than in alkaline water. Benzocaine produced deep anesthesia, but concentrations that rendered the fish handleable within 5 min were generally not safe for exposures longer than 15 min. Concentrations of benzocaine efficacious for fish were not acutely toxic to eggs of coho salmon (Oncorhynchus kisutch), chinook salmon (Oncorhynchus tshauiytschas, rainbow trout, brown trout, or lake trout (Salvelinus namaycush). Benzocaine is not registered for fishery use and is neither more effective nor safer than the registered anesthetic, tricaine methanesulfonate (MS-222l.

  19. Absence of fractionation of mercury isotopes during trophic transfer of methylmercury to freshwater fish in captivity

    PubMed Central

    Kwon, Sae Yun; Blum, Joel D; Carvan, Michael J; Basu, Niladri; Head, Jessica A; Madenjian, Charles P; David, Solomon R

    2015-01-01

    We performed two controlled experiments to determine the amount of mass-dependent and mass-independent fractionation (MDF and MIF) of methylmercury (MeHg) during trophic transfer into fish. In Experiment 1, juvenile yellow perch (Perca flavescens) were raised in captivity on commercial food pellets and then their diet was either maintained on un-amended food pellets (0.1 µg/g MeHg), or was switched to food pellets with 1.0 µg/g or 4.0 µg/g of added MeHg, for a period of 2 months. The difference in δ202Hg (MDF) and Δ199Hg (MIF) between fish tissues and food pellets with added MeHg were within the analytical uncertainty (δ202Hg; 0.07 ‰, Δ199Hg; 0.06 ‰) indicating no isotope fractionation. In Experiment 2, lake trout (Salvelinus namaycush) were raised in captivity on food pellets, and then shifted to a diet of bloater (Coregonus hoyi) for 6 months. The δ202Hg and Δ199Hg of the lake trout equaled the isotopic composition of the bloater after 6 months, reflecting re-equilibration of the Hg isotopic composition of the fish to new food sources and a lack of isotope fractionation during trophic transfer. We suggest that the stable Hg isotope ratios in fish can be used to trace environmental sources of Hg in aquatic ecosystems. PMID:22681311

  20. Absence of fractionation of mercury isotopes during trophic transfer of methylmercury to freshwater fish in captivity.

    PubMed

    Kwon, Sae Yun; Blum, Joel D; Carvan, Michael J; Basu, Niladri; Head, Jessica A; Madenjian, Charles P; David, Solomon R

    2012-07-17

    We performed two controlled experiments to determine the amount of mass-dependent and mass-independent fractionation (MDF and MIF) of methylmercury (MeHg) during trophic transfer into fish. In experiment 1, juvenile yellow perch (Perca flavescens) were raised in captivity on commercial food pellets and then their diet was either maintained on unamended food pellets (0.1 μg/g MeHg) or was switched to food pellets with 1.0 μg/g or 4.0 μg/g of added MeHg, for a period of 2 months. The difference in δ(202)Hg (MDF) and Δ(199)Hg (MIF) between fish tissues and food pellets with added MeHg was within the analytical uncertainty (δ(202)Hg, 0.07 ‰; Δ(199)Hg, 0.06 ‰), indicating no isotope fractionation. In experiment 2, lake trout (Salvelinus namaycush) were raised in captivity on food pellets and then shifted to a diet of bloater (Coregonus hoyi) for 6 months. The δ(202)Hg and Δ(199)Hg of the lake trout equaled the isotopic composition of the bloater after 6 months, reflecting reequilibration of the Hg isotopic composition of the fish to new food sources and a lack of isotope fractionation during trophic transfer. We suggest that the stable Hg isotope ratios in fish can be used to trace environmental sources of Hg in aquatic ecosystems. PMID:22681311

  1. NATIVE AND INTRODUCED LARVAL FISHES IN SUISAN MARSH, CALIFORNIA,: THE EFFECTS OF FRESHWATER FLOW

    EPA Science Inventory

    We sampled ichthyoplankton weekly in Suisun Marsh in the San Francisco Estuary from February to June each year from 1994 to 1999. We collected approximately 227,900 fish, predominantly shimofuri goby Tridentiger bifasciatus (60%) and prickly sculpin Cottus asper (33%). Principal ...

  2. Continental paleothermometry and seasonality using the isotopic composition of aragonitic otoliths of freshwater fishes

    NASA Astrophysics Data System (ADS)

    Patterson, William P.; Smith, Gerald R.; Lohmann, Kyger C.

    To investigate the applicability of oxygen isotope themometry using fish aragonite, the δ18O values of paired otolith and water samples were analyzed from six large modem temperate lakes. Otoliths are accretionaiy aragonitic structures which are precipitated within the sacculus of fish ears. Deep-water obligate benthic species from the hypolimnion of the Laurentian Great Lakes of North America and Lake Baikal, Siberia, provided cold-water end member values for aragonite δ18O. Warm-water values were obtained from naturally grown warm-water stenothermic species and from fish grown in aquaria under controlled conditions. These two groups, which represent growth over a temperature range of 3.2-30.3°C. were employed to determine the oxygen isotope temperature fractionation relationship for aragonite-water: 103lnα = 18.56 (±0.319)·(103)T-1 K -33.49 (±0.307). Empirical calibration of a fish aragonite thennometry equation allows its direct application to studies of paleoclimate. For example, high-resolution sampling of shallow-water eurythermic species coupled with a knowledge of the isotopic composition of meteoric waters can be used to determine seasonal temperature variation. This approach was tested using a modem shallow-water eurythermic species from Sandusky Bay, Lake Erie. Temperatures calculated from carbonate composition agree with meteorological records from the Sandusky Bay weather station for the same time period.

  3. The inner ears of Northern Canadian freshwater fishes following exposure to seismic air gun sounds.

    PubMed

    Song, Jiakun; Mann, David A; Cott, Peter A; Hanna, Bruce W; Popper, Arthur N

    2008-08-01

    An earlier study examined the effects of exposure to seismic air guns on the hearing of three species of fish from the Mackenzie River Delta in Northern Canada [Popper et al. (2005). "Effects of exposure to seismic airgun use on hearing of three fish species," J. Acoust. Soc. Am. 117, 3958-3971]. The sound pressure levels to which the fishes were exposed were a mean received level of 205-209 dB re 1 microPa (peak) per shot and an approximate received mean SEL of 176-180 dB re 1 microPa(2) s per shot. In this report, the same animals were examined to determine whether there were effects on the sensory cells of the inner ear as a result of the seismic exposure. No damage was found to the ears of the fishes exposed to seismic sounds despite the fact that two of the species, adult northern pike and lake chub, had shown a temporary threshold shift in hearing studies. PMID:18681621

  4. The inner ears of Northern Canadian freshwater fishes following exposure to seismic air gun sounds

    PubMed Central

    Song, Jiakun; Mann, David A.; Cott, Peter A.; Hanna, Bruce W.; Popper, Arthur N.

    2008-01-01

    An earlier study examined the effects of exposure to seismic air guns on the hearing of three species of fish from the Mackenzie River Delta in Northern Canada [Popper et al. (2005). “Effects of exposure to seismic airgun use on hearing of three fish species,” J. Acoust. Soc. Am. 117, 3958–3971]. The sound pressure levels to which the fishes were exposed were a mean received level of 205–209 dB re 1 μPa (peak) per shot and an approximate received mean SEL of 176–180 dB re 1 μPa2 s per shot. In this report, the same animals were examined to determine whether there were effects on the sensory cells of the inner ear as a result of the seismic exposure. No damage was found to the ears of the fishes exposed to seismic sounds despite the fact that two of the species, adult northern pike and lake chub, had shown a temporary threshold shift in hearing studies. PMID:18681621

  5. Devicyprin induced gonadal impairment in a freshwater food fish, Channa punctatus (Bloch).

    PubMed

    Srivastava, Rajesh K; Yadav, Kamlesh K; Trivedi, Sunil P

    2008-03-01

    Synthetic pyrethroids are the recent major class of broad spectrum, photostable, organic insecticides used in agricultural, domestic and veterinary applications and now account for more than 30% of global insecticide use. Cypermethrin is metabolized and eliminated significantly more slowly by fish than by mammals or birds, which may explain this compound's high toxicity in fish compared to other organisms. The present communication deals with histoanatomical alterations in the gonads of a local fresh water food fish, Channa punctatus exposed to 0.033 ppm (96 hr LC50 X 1/10) concentration of a synthetic pyrethroid, devicyprin (cypermethrin 25%) in aquatic medium of aged tap water for 15, 30 and 45 days respectively. In testis, exposure dependent histological damage has been observed in terms of vacuolization, condensation of spermatogonic cells, distortion of tubular epithelium, shrinkage of interstitial cells and general inflammatory responses. Longest exposure of 45 days has resulted in peculiar starry-sky appearance of the testicular tissue. Gross histo-anatomy of ovarian tissue reveals epithelial lesions, inflammatory responses, stromal hemorrhage, increased interstitium and shrinkage of yolk vesicles towards periphery These findings are quite suggestive of reproductive impairments leading to delayed gonadal maturity and adversely affecting processes of sperm production and ovulation and thus, the fish production. PMID:18831372

  6. RELATIVE BINDING AFFINITY OF ENDOCRINE DISRUPTING CHEMICALS TO ESTROGEN RECEPTOR IN TWO SPECIES OF FRESHWATER FISH

    EPA Science Inventory

    The US EPA has been mandated to screen industrial chemicals and pesticides for potential endocrine activity. To evaluate the potential for chemicals to cause endocrine disruption in fish we have previously measured the affinity of a number of chemicals for the rainbow trout estr...

  7. Condition dependent intra-individual repeatability of stress-induced cortisol in a freshwater fish.

    PubMed

    Cook, K V; O'Connor, C M; McConnachie, S H; Gilmour, K M; Cooke, S J

    2012-03-01

    The glucocorticoid (GC) stress response is thought to be an individual trait associated with behaviour and life history strategies. Studies exploring such relationships typically assume measured hormone values to be repeatable within an individual. However, repeatability of GCs has proven variable in wild animals and underlying reasons remain unknown. We assessed individual repeatability of circulating stress-induced cortisol, the primary GC in teleost fish, and glucose concentrations in a wild teleost fish held under consistent laboratory conditions. We also tested the hypothesis that the magnitude of intra-individual variability in stress-induced cortisol concentrations ("cortisol variability") is influenced by body condition. Wild-caught bluegill sunfish (Lepomis macrochirus) were subjected to repeated standardized stressors and blood sampled (3 times over 6 days) once cortisol concentrations peaked. Various indicators of fish condition, both whole body and physiological, were also measured. Overall, stress-induced circulating cortisol concentrations were repeatable but stress-induced glucose was not. Cortisol variability was related to Fulton's condition factor and size (eviscerated mass) where smaller fish in poor condition exhibited increased cortisol variability. The findings have implications for the interpretation of studies that examine correlates of GC concentrations as they suggest consistency in stress responsiveness is influenced by factors such as size and condition. PMID:22179071

  8. Absence of fractionation of mercury isotopes during trophic transfer of methylmercury to freshwater fish in captivity

    USGS Publications Warehouse

    Kwon, Sae Yun; Blum, Joel D.; Carvan, Michael J.; Basu, Niladri; Head, Jessica A.; Madenjian, Charles P.; David, Solomon R.

    2012-01-01

    We performed two controlled experiments to determine the amount of mass-dependent and mass-independent fractionation (MDF and MIF) of methylmercury (MeHg) during trophic transfer into fish. In experiment 1, juvenile yellow perch (Perca flavescens) were raised in captivity on commercial food pellets and then their diet was either maintained on unamended food pellets (0.1 μg/g MeHg) or was switched to food pellets with 1.0 μg/g or 4.0 μg/g of added MeHg, for a period of 2 months. The difference in δ202Hg (MDF) and Δ199Hg (MIF) between fish tissues and food pellets with added MeHg was within the analytical uncertainty (δ202Hg, 0.07 ‰; Δ199Hg, 0.06 ‰), indicating no isotope fractionation. In experiment 2, lake trout (Salvelinus namaycush) were raised in captivity on food pellets and then shifted to a diet of bloater (Coregonus hoyi) for 6 months. The δ202Hg and Δ199Hg of the lake trout equaled the isotopic composition of the bloater after 6 months, reflecting reequilibration of the Hg isotopic composition of the fish to new food sources and a lack of isotope fractionation during trophic transfer. We suggest that the stable Hg isotope ratios in fish can be used to trace environmental sources of Hg in aquatic ecosystems.

  9. METAL TOXICITY TO EMBRYOS AND LARVAE OF EIGHT SPECIES OF FRESHWATER FISH--II: COPPER

    EPA Science Inventory

    Fish larvae and early juveniles of all species tested (brook trout, rainbow trout, brown trout, lake trout, northern pike, white sucker, herring and smallmouth bass) were more sensitive to copper than the embryos. Embryo survival was affected only at the higher concentrations tes...

  10. Toxicity of retene to early life stages of two freshwater fish species

    SciTech Connect

    Billiard, S.M.; Querbach, K.; Hodson, P.V.

    1999-09-01

    Larval zebrafish (Danio rerio) were exposed for 14 d to graded nominal concentrations of waterborne retene (7-isopropyl-1-methylphenanthrene) from 5 to 336 h postfertilization. Reduced growth, yolk sac edema, and mortality were observed before swim up at nominal concentrations of 320 {micro}g/L and higher in a concentration-dependent manner. Similarly, exposures of rainbow trout (Oncorhynchus mykiss) to retene (32--320 {micro}g/L) for 42 d from the eyed egg stage to hatch and from hatch to the onset of swim up behavior caused exposure-related increases in blue sac disease posthatch. Symptoms included increased activity of cytochrome P4501A (CYPIA) enzymes, yolk sac edema, subcutaneous hemorrhaging, reduced growth, and craniofacial malformations. Chronic exposure to retene resulted in mortality before swim up. Blue sac symptoms were observed in fish exposed to nominal concentrations as low as 32 {micro}g/L, the lowest concentration tested, and fin erosion and opercular sloughing were evident in 100% of retene-exposed swim up larvae. No symptoms were observed in control fish or in fish exposed to acetone, the solvent carrier. The observed pathology resembles the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity to developing stages of fish, and results suggest that chronic exposure to polycyclic aromatic hydrocarbons may be responsible for recruitment failure associated with pulp mill effluents and oil spills.

  11. How reproductive ecology contributes to the spread of a globally invasive fish.

    PubMed

    Deacon, Amy E; Ramnarine, Indar W; Magurran, Anne E

    2011-01-01

    Invasive freshwater fish represent a major threat to biodiversity. Here, we first demonstrate the dramatic, human-mediated range expansion of the Trinidadian guppy (Poecilia reticulata), an invasive fish with a reputation for negatively impacting native freshwater communities. Next, we explore possible mechanisms that might explain successful global establishment of this species. Guppies, along with some other notable invasive fish species such as mosquitofish (Gambusia spp.), have reproductive adaptations to ephemeral habitats that may enable introductions of very small numbers of founders to succeed. The remarkable ability of single pregnant guppies to routinely establish viable populations is demonstrated using a replicated mesocosm set up. In 86% of cases, these populations persisted for two years (the duration of the experiment). Establishment success was independent of founder origin (high and low predation habitats), and there was no loss of behavioural performance amongst mesocosm juveniles. Behavioural "signatures" of the founding locality were, however, evident in mesocosm fish. Our results demonstrate that introductions consisting of a single individual can lead to thriving populations of this invasive fish and suggest that particular caution should be exercised when introducing this species, or other livebearers, to natural water bodies. PMID:21957449

  12. Volatile dimethylsiloxanes in market seafood and freshwater fish from the Xúquer River, Spain.

    PubMed

    Sanchís, Josep; Llorca, Marta; Picó, Yolanda; Farré, Marinella; Barceló, Damià

    2016-03-01

    Volatile dimethylsiloxanes are a family of synthetic organosilicon-compounds, which have received rising attention because of their widespread use and occurrence in the environment. In the present work, an analytical method based on ultrasound-assisted solid-liquid extraction (USAE) followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) has been optimized and applied to assess the presence of eight volatile dimethyl siloxanes (VMS) (hexamethylcyclotrisiloxane (D3), octamethylcyclotetra-siloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6), octamethyltrisiloxane (MDM), decamethyltetrasiloxane (MD2M) and dodecamethylpentasiloxane (MD3M) and tetradecamethylhexasiloxane (MD4M)) in fish. The optimized method presented limits of quantification between 0.1 and 1.3 pg/g for linear volatile dimethylsiloxanes (lVMS) and between 13 and 39 pg/g for cyclic volatile dimethylsiloxanes (cVMS) and intraday relative standard deviation (between 1.9 and 7.0%). Recovery yields were between 71 and 92%. 40 fish samples collected in different markets in Barcelona, (Spain), and 16 samples of fish directly collected at the Xúquer River were analysed. cVMS were detected in almost all the river fish samples at concentrations between pg/g and ng/g, with a significant correlation between the fat content and VMS concentrations in fish. In addition, significant higher concentrations were found in market samples, suggesting sources of contamination from their manipulation and storage in indoor environments. Multivariate analyses were applied to the results and the siloxane profiles and analyte correlations are discussed. PMID:26747987

  13. Effects of pollution on freshwater organisms

    SciTech Connect

    Phipps, G.L.; Harden, M.J.; Leonard, E.N.; Roush, T.H; Spehar, D.L.; Stephan, C.E.; Pickering, Q.H.; Buikema, A.L. Jr.

    1984-06-01

    This review includes subjects in last year's reviews on effects of pollution on freshwater invertebrates and effects of pollution on freshwater fish and amphibians. This review also includes information on the effects of pollution on freshwater plants. 625 references.

  14. Molecular phylogeny and phylogeography of the Australian freshwater fish genus Galaxiella, with an emphasis on dwarf galaxias (G. pusilla).

    PubMed

    Unmack, Peter J; Bagley, Justin C; Adams, Mark; Hammer, Michael P; Johnson, Jerald B

    2012-01-01

    The freshwater fauna of Southern Australia is primarily restricted to the southwestern and southeastern corners of the continent, and is separated by a large, arid region that is inhospitable to this biota. This geographic phenomenon has attracted considerable interest from biogeographers looking to explain evolutionary diversification in this region. Here, we employed phylogenetic and phylogeographic approaches to evaluate the effect of this barrier on a group of four galaxiid fish species (Galaxiella) endemic to temperate Southern Australia. We also tested if continental shelf width has influenced connectivity among populations during low sea levels when rivers, now isolated, could have been connected. We addressed these questions by sampling each species across its range using multiple molecular markers (mitochondrial cytochrome b sequences, nuclear S7 intron sequences, and 49 allozyme loci). These data also allowed us to assess species boundaries, to refine phylogenetic affinities, and to estimate species ages. Interestingly, we found compelling evidence for cryptic species in G. pusilla, manifesting as allopatric eastern and western taxa. Our combined phylogeny and dating analysis point to an origin for the genus dating to the early Cenozoic, with three of the four species originating during the Oligocene-Miocene. Each Galaxiella species showed high levels of genetic divergences between all but the most proximate populations. Despite extensive drainage connections during recent low sea levels in southeastern Australia, populations of both species within G. pusilla maintained high levels of genetic structure. All populations experienced Late Pleistocene-Holocene population growth, possibly in response to the relaxation of arid conditions after the last glacial maximum. High levels of genetic divergence and the discovery of new cryptic species have important implications for the conservation of this already threatened group of freshwater species. PMID:22693638

  15. Molecular Phylogeny and Phylogeography of the Australian Freshwater Fish Genus Galaxiella, with an Emphasis on Dwarf Galaxias (G. pusilla)

    PubMed Central

    Unmack, Peter J.; Bagley, Justin C.; Adams, Mark; Hammer, Michael P.; Johnson, Jerald B.

    2012-01-01

    The freshwater fauna of Southern Australia is primarily restricted to the southwestern and southeastern corners of the continent, and is separated by a large, arid region that is inhospitable to this biota. This geographic phenomenon has attracted considerable interest from biogeographers looking to explain evolutionary diversification in this region. Here, we employed phylogenetic and phylogeographic approaches to evaluate the effect of this barrier on a group of four galaxiid fish species (Galaxiella) endemic to temperate Southern Australia. We also tested if continental shelf width has influenced connectivity among populations during low sea levels when rivers, now isolated, could have been connected. We addressed these questions by sampling each species across its range using multiple molecular markers (mitochondrial cytochrome b sequences, nuclear S7 intron sequences, and 49 allozyme loci). These data also allowed us to assess species boundaries, to refine phylogenetic affinities, and to estimate species ages. Interestingly, we found compelling evidence for cryptic species in G. pusilla, manifesting as allopatric eastern and western taxa. Our combined phylogeny and dating analysis point to an origin for the genus dating to the early Cenozoic, with three of the four species originating during the Oligocene-Miocene. Each Galaxiella species showed high levels of genetic divergences between all but the most proximate populations. Despite extensive drainage connections during recent low sea levels in southeastern Australia, populations of both species within G. pusilla maintained high levels of genetic structure. All populations experienced Late Pleistocene-Holocene population growth, possibly in response to the relaxation of arid conditions after the last glacial maximum. High levels of genetic divergence and the discovery of new cryptic species have important implications for the conservation of this already threatened group of freshwater species. PMID:22693638

  16. Laboratory Experiments on the Effects of Blade Strike from Hydrokinetic Energy Technologies on Larval and Juvenile Freshwater Fishes

    SciTech Connect

    Schweizer, Peter E; Cada, Glenn F; Bevelhimer, Mark S

    2012-03-01

    will make contact with the rotor blade or will bypass the blade while entrained in the boundary layer of water flowing over the blade surface. The study quantified both immediate and delayed mortalities (observed immediately, 3 hours, and 24 hours after encountering the blade) among freshwater YOY fish resulting from contact with the blade or turbulent flows in the wake of the blade.

  17. Cancer in wild freshwater fish populations with emphasis on the Great Lakes

    SciTech Connect

    Baumann, P.C.

    1984-01-01

    Papillomas in white sucker, gonadal tumors in carp x goldfish hybrids, and thyroid hyperplasia in coho salmon seem to be widespread in occurrence throughout the Great Lakes. In all cases, however, tumor incidence increases near areas contaminated by industrial effluents such as polychlorinated biphenyls, and polynuclear aromatic hydrocarbons (PAHs). Liver tumors in bullhead occur frequently at a site with large amounts of PAH in the sediment, and liver tumors in sauger and walleye occur in a lake which has been a dump site for copper mine wastes. Therefore, tumor incidence in certain species of fish may be a sensitive indicator of the level of carcinogenic compounds in the environment. The Great Lakes apparently contain a number of localized areas in which carcinogenic contaminants are now affecting the health of resident fish species. 15 references.

  18. Self-confidence of anglers in identification of freshwater sport fish

    USGS Publications Warehouse

    Chizinski, C.J.; Martin, D. R.; Pope, Kevin L.

    2014-01-01

    Although several studies have focused on how well anglers identify species using replicas and pictures, there has been no study assessing the confidence that can be placed in angler's ability to identify recreationally important fish. Understanding factors associated with low self-confidence will be useful in tailoring education programmes to improve self-confidence in identifying common species. The purposes of this assessment were to quantify the confidence of recreational anglers to identify 13 commonly encountered warm water fish species and to relate self-confidence to species availability and angler experience. Significant variation was observed in anglers self-confidence among species and levels of self-declared skill, with greater confidence associated with greater skill and with greater exposure. This study of angler self-confidence strongly highlights the need for educational programmes that target lower skilled anglers and the importance of teaching all anglers about less common species, regardless of skill level.

  19. Freshwater Fishes of Gunung Jerai, Kedah Darul Aman: A Preliminary Study

    PubMed Central

    Shah, Amir Shah Ruddin Md; Hashim, Zarul Hazrin; Sah, Shahrul Anuar Mohd

    2009-01-01

    A total of 37 fish species from 14 families were observed during surveys conducted from January to March 2005 at 8 selected streams near the Gunung Jerai Forest Reserve. The list includes two species (Rasbora trilineata and Systomus partipentazona) that were visually identified at the lower part of the Sungai Teroi stream. Single specimens of Leiocassis micropogon, Clarias macrocephalus and Hampala macrolepidota were also obtained at certain sampling stations. Devario regina and Systomus binotatus were the most abundant species at all sampling stations. However, the list is still incomplete as the study was carried out over a short time period and there are large areas that have not yet been surveyed. The presence of exotic species (Carassius auratus) at Sungai Badak indicates anthropogenic influences. Therefore, a long-term monitoring program for Gunung Jerai Forest Reserve streams should be planned and carried out to assess the impacts of future development on fish biodiversity and water quality. PMID:24575179

  20. Erythrocytic and leukocytic responses to cadmium poisoning in freshwater fish, Puntius conchonius Ham

    SciTech Connect

    Gill, T.S.; Pant, J.C.

    1985-04-01

    Chronically sublethal concentrations of cadmium caused conspicuous hematological anomalies in the cyprinid fish, Puntius conchonius. Exposure to 0.63 and 0.84 mg/liter cadmium chloride (1/20 and 1/15 of 96-hr LC/sub 50/) induced morphological aberrations in mature erythrocytes including cytoplasmic vacuolation, hypochromia, deterioration of cellular membrane, basophilic stippling of cytoplasm, clumping of chromatin material and extrusion of nuclei, and schistocytosis. Anomalous basophils and monocytes were also encountered though less frequently. Decreased erythrocyte counts, hemoglobin and hematocrit values were also associated with chronic cadmium poisoning. The mean corpuscular hemoglobin and mean corpuscular volume increased (30 days) but mean corpuscular hemoglobin concentration showed no obvious change. A significant thrombocytopenia (90 days), elevated small lymphocyte and basophil populations, and a mild neutropenia were manifested in the cadmium-exposed fish. Large lymphocytes were not significantly affected.

  1. Sex identification and PIT-tagging: tools and prospects for studying intersexual differences in freshwater fishes.

    PubMed

    Hulthén, K; Chapman, B B; Nilsson, P A; Hansson, L-A; Skov, C; Baktoft, H; Brodersen, J; Brönmark, C

    2014-02-01

    This study evaluated a technique to allow the long-term monitoring of individual fishes of known sex in the wild using sex confirmation in close proximity to the reproductive period combined with individual tagging. Hundreds of partially migratory roach Rutilus rutilus were tagged with passive integrated transponders (PIT) following sex determination in spring and various performance measures were compared with fish tagged outside the reproductive period in autumn. Short-term survival was >95% for R. rutilus sexed and tagged under natural field conditions. Total length (LT ) did not affect the probability of survival within the size range tagged (119-280 mm), nor were there differences in timing of migration the following season between individuals sexed and tagged in spring and individuals tagged in autumn (i.e. outside the reproductive period). Also, a similar per cent of R. rutilus sexed and tagged in spring and tagged in autumn migrated the following season (34·5 and 34·7%). Moreover, long-term recapture data revealed no significant differences in body condition between R. rutilus individuals sexed and tagged in spring, individuals tagged in autumn and unmanipulated individuals. The observed sex ratio of recaptured fish did not differ from the expected values of equal recapture rates between males and females. Hence, there is no observable evidence for an adverse effect of tagging close to the reproductive period and therefore this method is suitable for studying intersexual differences and other phenotypic traits temporarily expressed during reproduction at the individual level in fishes. PMID:24490936

  2. Procedures for use of freshwater fishes in the development of reproducible toxicological information.

    PubMed

    Marking, L L

    1984-05-01

    Toxicity testing with fish began early in this century, but standardized methods have been developed only within the last three decades. Standardized test procedures promote reproducibility of results; healthy fish properly handled and acclimated to test conditions are a given prerequisite. The principles of acute toxicity testing are important in the design of chronic tests for suspected carcinogens because certain factors influence the activity of chemicals or contaminants. The pH of test water is a critical factor in governing the uptake of chemicals by fish. Buffering is required so that uniform pH in waters of different hardnesses and different pHs in water of a given hardness are maintained. The importance of water quality control is graphically demonstrated by the lampricide 3-trifluoromethyl-4-nitrophenol; the toxicant is over 50 times more toxic in water at pH 6.5 than at pH 9.5. Results of laboratory tests on toxicity or carcinogenicity of single compounds in a clean environment represent an oversimplification of the real world because organisms are actually exposed to multiple chemicals or stresses. Because the environment is a complex interaction of physical, chemical, and biological factors that are extremely variable and dynamic, simulation of these systems in the laboratory is, at best, artificial; therefore, results developed must be considered to be predictive. PMID:6749253

  3. Conversion of carotenoids into vitamins A(1) and A(2) in two species of freshwater fish.

    PubMed

    Gross, J; Budowski, P

    1966-12-01

    1. Examination of two zooplankton species predominating in fish ponds, Daphnia magna and Chironomus larvae, revealed the presence of alpha- and beta-carotene, echinenone, canthaxanthin and 3-hydroxy-4-oxo-beta-carotene in Daphnia, and beta-carotene and cryptoxanthin ester in Chironomus. No specific provitamins A(2) (containing a 3,4-dehydro-beta-ionone ring) were detected. 2. Guppies (Lebistes reticulatus) and platies (Xiphophorus variatus) were found to form vitamin A from beta-carotene and from its oxygen-containing derivatives isozeaxanthin, canthaxanthin and astaxanthin. Slight conversion into vitamin A(2) seemed to occur simultaneously. 3,4-Dehydro-3'-hydroxy-beta-carotene formed little vitamin A, and the latter was mainly of the A(2) type. Lutein was devoid of provitamin A properties. 3. In addition to vitamin A, beta-carotene was detected in fish receiving the 4-oxo- and 4-hydroxy-carotenoids. A reaction scheme for the conversion of carotenoids into retinal and and 3,4-dehydroretinal is presented. 4. It is concluded that natural 4-oxo derivatives of beta-carotene may play a significant role as vitamin A precursors for fish. PMID:16742455

  4. Conversion of carotenoids into vitamins A1 and A2 in two species of freshwater fish

    PubMed Central

    Gross, Jeana; Budowski, P.

    1966-01-01

    1. Examination of two zooplankton species predominating in fish ponds, Daphnia magna and Chironomus larvae, revealed the presence of α- and β-carotene, echinenone, canthaxanthin and 3-hydroxy-4-oxo-β-carotene in Daphnia, and β-carotene and cryptoxanthin ester in Chironomus. No specific provitamins A2 (containing a 3,4-dehydro-β-ionone ring) were detected. 2. Guppies (Lebistes reticulatus) and platies (Xiphophorus variatus) were found to form vitamin A from β-carotene and from its oxygen-containing derivatives isozeaxanthin, canthaxanthin and astaxanthin. Slight conversion into vitamin A2 seemed to occur simultaneously. 3,4-Dehydro-3′-hydroxy-β-carotene formed little vitamin A, and the latter was mainly of the A2 type. Lutein was devoid of provitamin A properties. 3. In addition to vitamin A, β-carotene was detected in fish receiving the 4-oxo- and 4-hydroxy-carotenoids. A reaction scheme for the conversion of carotenoids into retinal and and 3,4-dehydroretinal is presented. 4. It is concluded that natural 4-oxo derivatives of β-carotene may play a significant role as vitamin A precursors for fish. PMID:16742455

  5. Agricultural sources of contaminants of emerging concern and adverse health effects on freshwater fish

    USGS Publications Warehouse

    Tillitt, Donald E.; Buxton, Herbert T.

    2011-01-01

    Agricultural contaminants of emerging concern (CECs) are generally thought of as certain classes of chemicals associated with animal feeding and production facilities. Veterinary pharmaceuticals used in animal food production systems represent one of the largest groups of CECs. In our review, we discuss the extensive increase in use of antibiotics in animal feeding operations (AFOs) around the world. AFOs are a major consumer of antibiotics and other veterinary pharmaceuticals and over the past decade there has been growing information on the occurrence, release, and fate of CECs from animal food production operations, including the application of pharmaceutical-containing manure to agricultural fields and releases from waste lagoons. Concentrations of CECs in surface and ground water in proximity to AFOs correspond to their presence in the AFO wastes. In many cases, the environmental concentrations of agriculturally-derived CECs are below toxicity thresholds. Hormones and hormone replacement compounds are a notable exception, where chemical concentrations near AFOs can exceed concentrations known to cause adverse effects on endocrine-related functions in fish. In addition, some agricultural pesticides, once thought to be safe to non-target organisms, have demonstrated endocrine-related effects that may pose threats to fish populations in agricultural regions. That is, we have pesticides with emerging concerns, thus, the concern is emerging and not necessarily the chemical. In this light, one must consider certain agricultural pesticides to be included in the list of CECs. Even though agricultural pesticides are routinely evaluated in regulatory testing schemes which have been used for decades, the potential hazards of some pesticides have only recently been emerging. Emerging concerns of pesticides in fish include interference with hormone signaling pathways; additive (or more than additive) effects from pesticide mixtures; and adverse population-level effects at

  6. Assessment of risk of PCDD/Fs and dioxin-like PCBs in marine and freshwater fish in Pearl River Delta, China.

    PubMed

    Wei, X; Leung, K S; Wong, M H; Giesy, J; Cai, Z W; Wong, Chris K C

    2011-01-01

    Fish consumption is known to be beneficial to human health. However since the age of industrialization, the released/disposed chemical pollutants into water systems make fish a source of various environmental toxicants to humans. In oceanic cities with heavy industrial activities, fish products contribute the greatest proportion of exposure to pollutants. In this study, risks and potential effects of dioxins to health of coastal populations in the Pearl River Delta were assessed. Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) were measured in common fish species purchased at local markets. Concentrations of total dioxins in fish ranged from 0.481 to 9.05 pg TEQ/g wet weight were similar to the lesser concentrations reported for fish from other countries. The greatest concentrations of dioxins were measured in mandarin fish, a carnivorous freshwater fish. Exposure of murine primary leydig and ovarian cells to 2,3,7,8-tetrachlorinated dibenzo-p-dioxins (2,3,7,8-TCDD) reduced the synthesis of progesterone, testosterone and/or estrogen. The reductions were probably via inhibitory effects on the expression of the steroidogenic enzymes, steroidogenic acute regulatory protein (StAR) and cytochrome P450 side-chain cleavage enzyme (P450scc). Based on these reproductive parameters, the concentrations of dioxins and dioxin-like residues represent a moderate health risk due to consumption of fish. PMID:21392810

  7. Behavioral and biochemical responses in freshwater fish Carassius auratus exposed to sertraline.

    PubMed

    Xie, Zhengxin; Lu, Guanghua; Li, Sheng; Nie, Yang; Ma, Binni; Liu, Jianchao

    2015-09-01

    Sertraline is one of the most commonly prescribed selective serotonin reuptake inhibitors and is frequently detected in the aquatic environment. However, knowledge regarding relationships among molecular or biochemical endpoints involved in modes of action (MOAs) of sertraline and ecologically important behavioral responses of fish is insufficient. The present study aimed to investigate the bioconcentration and possible adverse outcomes pathways (AOPs) in crucian carp (Carassius auratus) exposed to various concentrations of sertraline (4.36, 21.3 and 116 μg L(-1)) for 7 d. Bioconcentration factor values were in the range of 19.5-626 in liver, 6.94-285 in brain, 4.01-146 in gill and 0.625-43.1 in muscle during the entire period of exposure. Liver superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activities and brain acetylcholinesterase (AChE) activity were selected as biochemical endpoints associated with MOAs. Swimming activity, shoaling, feeding rate and food consumption were determined to assess behavioral responses. Fish plasma levels of sertraline exceeding human therapeutic doses were also predicted from external exposure concentrations. Significant enhancements in CAT, GPx, AChE and swimming activities and decreases in shoaling tendency, feeding rate and food consumption were observed when fish plasma levels exceeded human therapeutic thresholds. Shoaling, feeding rate and food consumption were correlated with the activities of SOD, CAT and GST. A significant positive correlation between swimming activity and AChE activity was also observed. As such, our study provides important AOPs linking biochemical responses with ultimate ecologically relevant behavioral endpoints. PMID:25950408

  8. Prevalence and characterization of plasmid-mediated quinolone resistance genes in Aeromonas spp. isolated from South African freshwater fish.

    PubMed

    Chenia, Hafizah Yousuf

    2016-08-16

    An increasing incidence of multidrug-resistant Aeromonas spp., which are both fish and emerging opportunistic human pathogens, has been observed worldwide. Quinolone-resistant Aeromonas spp. isolates are increasingly being observed in clinical and environmental settings, and this has been attributed primarily to target gene alterations, efflux, and transferable quinolone resistance. Thirty-four Aeromonas spp., obtained from freshwater aquaculture systems, were screened for the presence of GyrA and ParC substitutions, efflux activity and the prevalence of plasmid-mediated quinolone resistance genes, qnr and aac-6'-Ib-cr. Although 44% of isolates were resistant to nalidixic acid, the majority were susceptible to ciprofloxacin and ofloxacin. The predominant GyrA substitution was Ser-83→Val among Aeromonas veronii isolates whilst Aeromonas hydrophila isolates displayed a Ser-83→Ile substitution, and Ser-80→Ile substitutions were observed in ParC. Minimum inhibitory concentrations of fluoro(quinolones) were determined in the presence and absence of the efflux pump inhibitor, phenylalanine-arginine β-naphthylamide (PAβN). Addition of PAβN had no effect on the levels of fluoro(quinolone) resistance observed for these isolates. Although no aac-6'-Ib-cr variant genes were identified, qnrB and qnrS were detected for 41% and 24% of isolates, respectively, by Southern hybridization and confirmed by PCR and sequencing. Quinolone resistance in these fish-associated Aeromonas isolates was related to mutations in the quinolone resistance determining regions of GyrA and ParC and presence of qnrB and qnrS. The presence of qnr alleles in Aeromonas spp. isolates may facilitate high-level fluoroquinolone resistance and potentially serve as reservoirs for the dissemination of qnr genes to other aquatic microbes. PMID:27180024

  9. Toxicity assessment on haemotology, biochemical and histopathological alterations of silver nanoparticles-exposed freshwater fish Labeo rohita

    NASA Astrophysics Data System (ADS)

    Rajkumar, K. S.; Kanipandian, N.; Thirumurugan, R.

    2016-01-01

    The increasing use of nano based-products induces the potential hazards from their manufacture, transportation, waste disposal and management processes. In this report, we emphasized the acute toxicity of silver nanoparticles (AgNPs) using freshwater fish Labeo rohita as an aquatic animal model. The AgNPs were synthesized using chemical reduction method and the formation of AgNPs was monitored by UV-Visible spectroscopy analysis. The functional groups, crystaline nature and morphological characterizations were carried out by fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) analysis. UV-Vis range was observed at 420 nm and XRD pattern showed that the particles are crystalline nature. HRTEM analysis revealed that the morphology of particles was spherical and size ranges between 50 and 100 nm. This investigation was extended to determine the potential acute toxicity, L. rohita was treated orally with the lethal concentration (LC50) of AgNPs. The antioxidative responses were studied in the three major tissues such as gill, liver and muscle of L. rohita. The results of this investigation showed that increasing the concentration of AgNPs led to bioaccumulation of AgNPs in the major tissues. The haematological parameters showed significant alterations in the treated fish. The histological changes caused by chemically synthesized AgNPs demonstrated the damages in the tissues, primary lamella and blood vessels of L. rohita. The histological study also displayed the formation of vacuolation in liver and muscle when compared with untreated tissues (control) of L. rohita.

  10. Out-of-season sperm cryopreserved in different media of the Amazonian freshwater fish pirapitinga (Piaractus brachypomus).

    PubMed

    Nascimento, A F; Maria, A N; Pessoa, N O; Carvalho, M A M; Viveiros, A T M

    2010-04-01

    The pirapitinga (Piaractus brachypomus) is a freshwater fish that inhabits the Amazon and Orinoco River basins. The use of cryopreserved sperm has been considered to facilitate procedures during the artificial reproduction. The aim of the present study was to develop a freezing protocol for pirapitinga sperm collected outside the spawning season. Sperm samples were diluted in four freezing media prepared by a combination of two extenders (glucose and BTS-Beltsville Thawing Solution) and two cryoprotectant agents (DMSO and methylglycol) loaded into 0.5-mL straws, frozen in a nitrogen-vapor shipping dewar (dry-shipper) and stored in liquid nitrogen at -196 degrees C. Post-thaw sperm motility was evaluated both subjectively using a light microscope and by a computer-assisted sperm analyzer (CASA). Curvilinear, average path and straight-line velocities were also determined. There were no differences (P>0.05) in post-thaw sperm motility between evaluations performed subjectively and using the CASA. Sperm samples cryopreserved in glucose-methylglycol yielded the greatest post-thaw sperm motility (81%) and fastest sperm velocities when compared to the samples frozen in the other three media (P<0.05). Out-of-season sperm cryopreserved in glucose and methylglycol under the conditions described above is of high quality and can therefore be used to facilitate artificial reproduction procedures, as only females will need handling for hormonal induction and gamete collection during the spawning season. Although the CASA system provides precise data on sperm motility, the subjective evaluation is practical and can be conducted by well-trained personnel at commercial fish farms as an acceptable evaluation of sperm quality. PMID:19679412

  11. Ecotoxicological effects of carbofuran and oxidised multiwalled carbon nanotubes on the freshwater fish Nile tilapia: nanotubes enhance pesticide ecotoxicity.

    PubMed

    Campos-Garcia, Janaína; Martinez, Diego Stéfani T; Alves, Oswaldo L; Leonardo, Antônio Fernando Gervásio; Barbieri, Edison

    2015-01-01

    The interactions of carbon nanotubes with pesticides, such as carbofuran, classical contaminants (e.g., pesticides, polyaromatic hydrocarbons, heavy metals, and dyes) and emerging contaminants, including endocrine disruptors, are critical components of the environmental risks of this important class of carbon-based nanomaterials. In this work, we studied the modulation of acute carbofuran toxicity to the freshwater fish Nile tilapia (Oreochromis niloticus) by nitric acid treated multiwalled carbon nanotubes, termed HNO3-MWCNT. Nitric acid oxidation is a common chemical method employed for the purification, functionalisation and aqueous dispersion of carbon nanotubes. HNO3-MWCNT were not toxic to Nile tilapia at concentrations ranging from 0.1 to 3.0 mg/L for exposure times of up to 96 h. After 24, 48, 72 and 96 h, the LC50 values of carbofuran were 4.0, 3.2, 3.0 and 2.4 mg/mL, respectively. To evaluate the influence of carbofuran-nanotube interactions on ecotoxicity, we exposed the Nile tilapia to different concentrations of carbofuran mixed together with a non-toxic concentration of HNO3-MWCNT (1.0 mg/L). After 24, 48, 72, and 96 h of exposure, the LC50 values of carbofuran plus nanotubes were 3.7, 1.6, 0.7 and 0.5 mg/L, respectively. These results demonstrate that HNO3-MWCNT potentiate the acute toxicity of carbofuran, leading to a more than five-fold increase in the LC50 values. Furthermore, the exposure of Nile tilapia to carbofuran plus nanotubes led to decreases in both oxygen consumption and swimming capacity compared to the control. These findings indicate that carbon nanotubes could act as pesticide carriers affecting fish survival, metabolism and behaviour. PMID:25450925

  12. Five new species of Urocleidoides (Monogenoidea) (Mizelle and Price 1964) Kritsky, Thatcher, and Boeger, 1986, parasitizing the gills of Panamanian freshwater fishes.

    PubMed

    Mendoza-Franco, Edgar F; Reina, Ruth G

    2008-08-01

    During an investigation of gill monogenoidean parasites from freshwater fishes in central Panama, 5 new species of Urocleidoides (sensu stricto) were found: Urocleidoides cultellus n. sp., Urocleidoides visiofortatus n. sp., and Urocleidoides advenai n. sp. from the gymnotiform Brachyhypopomus occidentalis (Hypopomidae); Urocleidoides neotropicalis n. sp. and Urocleidoides piriatiu n. sp. from the characiforms Saccodon dariensis (Parodontidae) and Ctenolucius beani (Ctenoluciidae), respectively. Our findings represent the first known species of Urocleidoides from these fishes in Central America and demonstrate that they are morphologically linked to their South American congeners. PMID:18837577

  13. Distinct migratory and non-migratory ecotypes of an endemic New Zealand eleotrid (Gobiomorphus cotidianus) – implications for incipient speciation in island freshwater fish species

    PubMed Central

    2008-01-01

    Background Many postglacial lakes contain fish species with distinct ecomorphs. Similar evolutionary scenarios might be acting on evolutionarily young fish communities in lakes of remote islands. One process that drives diversification in island freshwater fish species is the colonization of depauperate freshwater environments by diadromous (migratory) taxa, which secondarily lose their migratory behaviour. The loss of migration limits dispersal and gene flow between distant populations, and, therefore, is expected to facilitate local morphological and genetic differentiation. To date, most studies have focused on interspecific relationships among migratory species and their non-migratory sister taxa. We hypothesize that the loss of migration facilitates intraspecific morphological, behavioural, and genetic differentiation between migratory and non-migratory populations of facultatively diadromous taxa, and, hence, incipient speciation of island freshwater fish species. Results Microchemical analyses of otolith isotopes (88Sr, 137Ba and 43Ca) differentiated migratory and non-migratory stocks of the New Zealand endemic Gobiomorphus cotidianus McDowall (Eleotridae). Samples were taken from two rivers, one lake and two geographically-separated outgroup locations. Meristic analyses of oculoscapular lateral line canals documented a gradual reduction of these structures in the non-migratory populations. Amplified fragment length polymorphism (AFLP) fingerprints revealed considerable genetic isolation between migratory and non-migratory populations. Temporal differences in reproductive timing (migratory = winter spawners, non-migratory = summer spawners; as inferred from gonadosomatic indices) provide a prezygotic reproductive isolation mechanism between the two ecotypes. Conclusion This study provides a holistic look at the role of diadromy in incipient speciation of island freshwater fish species. All four analytical approaches (otolith microchemistry, morphology

  14. Notes on the occurrence of Trypanosoma sp. (Kinetoplastida: Trypanosomatidae) in freshwater fishes from South Africa.

    PubMed

    Ferreira, Maryke L; Avenant-Oldewage, Annemariè

    2013-01-01

    A total of 257 fishes from four families, Clariidae, Cichlidae, Cyprinidae and Schilbeidae were collected from three localities: the Sand River Dam, Swaziland; the Nylsvlei Nature Reserve, South Africa and the Vaal Dam and Vaal River Barrage, South Africa. Only fishes (n= 154) from Clariidae and Cichlidae were found to be infected with trypanosomes. A total of 221 Clarias gariepinus (Burchell 1822) were collected from the Vaal Dam and Vaal Barrage area, South Africa. Of these, 74%(89/121) were infected with trypanosomes from the Vaal Dam and 63%(63/100) from the Vaal River Barrage, with no seasonal infection pattern. A prevalence of 25%(1/4) was found in C. gariepinus from the Sand River Dam, Swaziland, and a 50% (1/2) prevalence was found in Tilapia sparrmanii from the Nylsvlei Nature Reserve, South Africa. Standard measurements conformed closely to the morphometric and morphological descriptions of Trypanosoma mukasai. This article provides new locality records for T. mukasai from the Vaal Dam, Vaal River Barrage and Nylsvlei Nature Reserve (South Africa) and the Sand River Dam (Swaziland). Tilapia sparrmanii collected in the Sand River Dam in Swaziland is also noted as a new host record. PMID:23718161

  15. Unraveling the sequence information in COI barcode to achieve higher taxon assignment based on Indian freshwater fishes.

    PubMed

    Chakraborty, Mohua; Ghosh, Sankar Kumar

    2015-04-01

    Efficacy of cytochrome c oxidase subunit I (COI) DNA barcode in higher taxon assignment is still under debate in spite of several attempts, using the conventional DNA barcoding methods, to assign higher taxa. Here we try to understand whether nucleotide and amino acid sequence in COI gene carry sufficient information to assign species to their higher taxonomic rank, using 160 species of Indian freshwater fishes. Our results reveal that with increase in the taxonomic rank, sequence conservation decreases for both nucleotides and amino acids. Order level exhibits lowest conservation with 50% of the nucleotides and amino acids being conserved. Among the variable sites, 30-50% were found to carry high information content within an order, while it was 70-80% within a family and 80-99% within a genus. High information content shows sites with almost conserved sequence but varying at one or two locations, which can be due to variations at species or population level. Thus, the potential of COI gene in higher taxon assignment is revealed with validation of ample inherent signals latent in the gene. PMID:24409929

  16. Aquatic safety of Lagenidium giganteum: effects on freshwater fish and invertebrates.

    PubMed

    Nestrud, L B; Anderson, R L

    1994-11-01

    Eleven freshwater species were exposed to a zoosporeproducing fungus, Lagenidium giganteum, with the goal of determining species sensitivity with standard and new test procedures. The tests included standard, 4-day acute exposures of cladocerans (Ceriodaphnia dubia, Daphnia pulex, and D. magna) and the fathead minnow (Pimephales promelas). Standard 7-day chronic exposures of C. dubia and a 7-day embryo-larval exposure of P. promelas were also conducted. New, 4-day acute, methods were developed for mosquitos (Aedes aegypti), chironomids (Chironomus sp.), oligochaetes (Lumbriculus sp.), cyclopoid copepods, snails (Physa sp.), hydrozoans (Hydra sp.), and ostracods. To assess L. giganteum zoospore (z) infectivity, each test included daily bioassays with the mosquito (A. aegypti), a target organism. Four-day A. aegypti LC50s ranged from 81 to 516 z/ml. Ceriodaphnia dubia acute test LC50s were as low as 6700 z/ml and the 96-hr LC50 from the chronic test was near 6250 z/ml with reproductive impairment at 12,500 z/ml. Daphnia sp. were also susceptible, with LC50s near 7700 z/ml for D. pulex and 9400 z/ml for D. magna. Chironomus tentans was infected at concentrations of > or = 5000 z/ml, but mortality was low and an LC50 could not be calculated even after exposures to 50,000 z/ml. The 7-day, early life stage test with P. promelas produced reduced larva growth in most treatments. Several species (Hydra sp., L. variegatus, ostracoda, copepoda, Physa sp., and P. promelas) were not affected in acute tests at exposures of 50,000 z/ml. The data show, contrary to many reports, that L. giganteum may affect some nontarget aquatic species. The key to successful laboratory tests is monitoring and maintaining the zoospores infection capacity. PMID:7806894

  17. Factors influencing tropical island freshwater fishes:Species, status, and management implications in puerto rico [Factores que influencian a los peces tropicales de agua dulce: Especies, estado actual e implicaciones para el manejo en Puerto Rico

    USGS Publications Warehouse

    Wesley, Neal J.; Lilyestrom, C.G.; Kwak, T.J.

    2009-01-01

    Anthropogenic effects including river regulation, watershed development, contamination, and fish introductions have substantially affected the majority of freshwater habitats in Europe and North America. This pattern of resource development and degradation is widespread in the tropics, and often little is known about the resources before they are lost. This article describes the freshwater resources of Puerto Rico and identifies factors that threaten conservation of native fishes. The fishes found in freshwater habitats of Puerto Rico represent a moderately diverse assemblage composed of 14 orders, 29 families, and 82 species. There are fewer than 10 species of native peripherally-freshwater fish that require a link to marine systems. Introductions of nonindigenous species have greatly expanded fish diversity in freshwater systems, and native estuarine and marine species (18 families) also commonly enter lowland rivers and brackish lagoons. Environmental alterations, including land use and development, stream channelization, pollution, and the impoundment of rivers, combined with nonnative species introductions threaten the health and sustainability of aquatic resources in Puerto Rico. Six principal areas for attention that are important influences on the current and future status of the freshwater fish resources of Puerto Rico are identified and discussed.

  18. Variable survival across low pH gradients in freshwater fish species.

    PubMed

    Jellyman, P G; Harding, J S

    2014-11-01

    A series of 14 day experiments was conducted on five common New Zealand fish species (redfin bully Gobiomorphus huttoni, inanga Galaxias maculatus, brown trout Salmo trutta, longfin eel Anguilla dieffenbachii and koaro Galaxias brevipinnis) to assess the effect of pH on survival and changes in body mass. No species survived in water of pH <4 although there was 100% survival of all adults at pH 4.5, G. maculatus larvae were also tested and had high mortality at this pH. Results suggest that adults are tolerant of low-pH waters; however, successful remediation of anthropogenically acidified streams will require an understanding of the susceptibility to low pH on different life cycle stages. PMID:25230112

  19. [Diet of the tropical freshwater fish Heterandria bimaculata (Haeckel) and Poecilia sphenops Valenciennes (Cyprinidontiformes: Poeciliidae)].

    PubMed

    Trujillo-Jiménez, Patricia; Beto, Héctor Toledo

    2007-06-01

    We analyzed the diet and feeding habits of the fishes Heterandria bimaculata and Poecilia sphenops. Specimens were captured monthly in "Los Carros" damp, Morelos, Mexico (18 degrees 37' N, 98 degrees 43' W). We quantified gut content by the numerical method and by the frequency of occurrence method; and used the MacArthur and Levin's indices for niche overlap. The diet of H. bimaculata was composed by 16 prey categories, mainly dipterans (Culicidae predominated), independently of sex, size and season. The index of niche overlap was high, from 0.74 to 0.99. The diet of P. sphenops consisted of 11 items, detritus being the most consumed, also independently of sex, size and season. The niche overlap index was high (0.99), indicating overlapping for all analyses. There was little diet overlap (0.26) between the two species. PMID:19069770

  20. Individuals' diet diversity influences gut microbial diversity in two freshwater fish (threespine stickleback and Eurasian perch)

    PubMed Central

    Bolnick, Daniel I; Snowberg, Lisa K; Hirsch, Philipp E; Lauber, Christian L; Knight, Rob; Caporaso, J Gregory; Svanbäck, Richard; Post, David

    2014-01-01

    Vertebrates' diets profoundly influence the composition of symbiotic gut microbial communities. Studies documenting diet-microbiota associations typically focus on univariate or categorical diet variables. However, in nature individuals often consume diverse combinations of foods. If diet components act independently, each providing distinct microbial colonists or nutrients, we expect a positive relationship between diet diversity and microbial diversity. We tested this prediction within each of two fish species (stickleback and perch), in which individuals vary in their propensity to eat littoral or pelagic invertebrates or mixtures of both prey. Unexpectedly, in most cases individuals with more generalised diets had less diverse microbiota than dietary specialists, in both natural and laboratory populations. This negative association between diet diversity and microbial diversity was small but significant, and most apparent after accounting for complex interactions between sex, size and diet. Our results suggest that multiple diet components can interact non-additively to influence gut microbial diversity. PMID:24847735

  1. [Citogenetic characterization of the tropical freshwater fish Parachromis managuensis (Pisces: Cichlidae)].

    PubMed

    Arias-Rodríguez, Lenin; Páramo-Delgadillo, Salomón; Durán-González, Alicia de la Luz

    2006-03-01

    To describe the cytogenetics of the jaguar cichlid fish Parachromis managuensis, we collected eight males and 13 females in Villahermosa, Tabasco, México. The specimens were processed with standard cytogenetic techniques (slightly modified), and high quality fields of chromosomes in mitosis and meiosis were obtained; 14 of these fields were analyzed by meristics and statistics methods. The specimens presented a diploid modal number of 2n = 48 chromosomes, which is similar to the number reported for others Central American cichlids; five pairs were submetacentric-metacentrics (biarmed) and 19 were subtelocentric-telocentric (uni-armed), giving a fundamental number (NF) of 58. The haploid number was confirmed by counting meiotic fields in metaphase I. There was not evidence of heteromorphism: sexual chromosomes were not identifiable. PMID:18457172

  2. Distribution of mercury in the tissues of five species of freshwater fish from Lake Mead, USA.

    PubMed

    Cizdziel, J; Hinners, T; Cross, C; Pollard, J

    2003-10-01

    Total mercury (Hg) concentrations were determined in seven tissues (skeletal muscle, liver, blood, gonad, brain, gill, and heart) of 59 striped bass and four tissues (muscle, liver, blood, and gonad) of 69 largemouth bass, 76 channel catfish, 12 bluegill, and 22 blue tilapia collected from Lake Mead, USA. Mercury levels generally increased according to trophic level and fish length. For striped bass, mean Hg levels (ng g(-1), wet mass) were highest in the liver (531), followed by muscle (309), heart (186), gonad (136), brain (77), gill (52), and blood (36). Similarly, Hg levels in the catfish and tilapia were liver > muscle > gonad > blood. In contrast, largemouth bass and bluegill had the highest levels in muscle, followed by liver, gonad, and blood. Generally, Hg levels were strongly correlated among the tissues, especially for blood/muscle and blood/liver. As the body burden of Hg increased, the concentration in blood and organs increased relative to the concentration in muscle. The trend was most pronounced for the liver. These relationships could form the basis of a predictive model and suggest that blood and muscle (plugs) could be useful for a non-lethal measure of Hg concentration and exposure in fish. For the striped bass, elevated Hg levels in the tissues were also correlated with degree of emaciation. Liver-to-muscle ratios were similar to literature values, except for tilapia with an average ratio of approximately 1.7, which is higher than generally reported for non-piscivores. Finally, this study demonstrates the usefulness of a solid sampling approach in trace element monitoring, especially as pertaining to in vivo analysis, analysis of a large number of samples and reduction of contamination risk. PMID:14587853

  3. Effects of trophic exposure to dexamethasone and diclofenac in freshwater fish.

    PubMed

    Guiloski, Izonete Cristina; Ribas, João Luiz Coelho; Pereira, Letícia da Silva; Neves, Ana Paula Perbiche; Silva de Assis, Helena Cristina

    2015-04-01

    Steroidal and non-steroidalanti-inflammatories are pharmaceutical prescribed in human medicine and have the potential to contaminate water and sediments via inputs from sewage treatment plants. Their impacts on humans and ecosystems are emerging issues in environmental health. The aim of the present work was to evaluate the effects of diclofenac and dexamethasone in male fish Hoplias malabaricus after trophic exposure. Fish were fed twice every week with Astyanax sp. submitted to intraperitoneal inoculation with diclofenac (0; 0.2; 2.0 or 20.0 μg/kg) or dexamethasone (0; 0.03; 0.3 or 3.0 μg/kg). After 12 doses, blood was collected for testosterone dosage. The gonad and liver were collected to calculate gonadosomatic (GSI) and hepatosomatic index (HSI). Antioxidants enzymes activity and biotransformation were also evaluated in liver and gonads. In liver, diclofenac caused oxidative stress with increased superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and lipoperoxidation (LPO). The GST activity was reduced by diclofenac in liver. Trophic exposure of H. malabaricus to dexamethasone caused an increase in antioxidant system (GPx, CAT, GST, and GSH) and LPO in liver. However, it reduced antioxidant system (GPX and GST activities and GSH) in gonads. Both diclofenac and dexamethasone reduced the levels of testosterone, causing impairment to reproduction. Diclofenac reduced HSI at the 0.2 μg/kg, but not GSI. Our results suggest that the anti-inflammatory drugs diclofenac and dexamethasone caused oxidative stress and reduced testosterone levels that can have a negative impact in aquatic organisms. PMID:25645142

  4. Effects of anti-inflammatory drugs in primary kidney cell culture of a freshwater fish.

    PubMed

    Ribas, João Luiz Coelho; da Silva, Cesar A; de Andrade, Lucas; Galvan, Gabrieli Limberger; Cestari, Marta Margarete; Trindade, Edvaldo S; Zampronio, Aleksander R; de Assis, Helena C Silva

    2014-09-01

    The non-steroidal anti-inflammatory drugs are emerging contaminants in aquatic ecosystems. This study aimed to evaluate toxic effects of some representative drugs of this pharmaceutical group on primary culture of monocytic lineage of Hoplias malabaricus anterior kidney. The effects of diclofenac, acetaminophen and ibuprofen in cell viability, lipopolysaccharide (LPS)-induced NO production and genotoxicity were evaluated. Cytometry analysis CD11b(+) cells showed 71.5% of stem cells, 19.5% of macrophages and 9% of monocytes. Cell viability was lower in the ficoll compared to percoll separation. LPS-induced NO production by these cells was blocked after treatment with dexamethasone and NG-Methyl-L-Arginine (L-NMMA). Exposure of the cells to diclofenac (0.2-200 ng/mL), acetaminophen (0.025-250 ng/mL) ibuprofen (10-1000 ng/mL) reduced basal NO production and inhibited LPS-induced NO production at all concentrations after 24 h of exposure. Genotoxicity occurred at the highest concentration of diclofenac and at the intermediary concentration of acetaminophen. Genotoxicity was also observed by ibuprofen. In summary, the pharmaceuticals influenced NO production and caused DNA damage in monocytic cells suggesting that these drugs can induce immunosuppression and genotoxicity in fish. PMID:25038277

  5. Enantioselective analysis of non-steroidal anti-inflammatory drugs in freshwater fish based on microextraction with a supramolecular liquid and chiral liquid chromatography-tandem mass spectrometry.

    PubMed

    Caballo, Carmen; Sicilia, Maria Dolores; Rubio, Soledad

    2015-06-01

    Toxicity of pharmaceuticals to aquatic biota is still largely unknown, and no research on the stereoselective toxicity of chiral drugs to these organisms has been undertaken to date. Because of the lack of analytical methods available for this purpose, this manuscript deals, for the first time, with the enantioselective analysis of the non-steroidal anti-inflammatory drugs (NSAIDs) ibuprofen, naproxen and ketoprofen in freshwater fish. The method was based on the microextraction of NSAIDs from fish muscle with a supramolecular liquid made up of inverted hexagonal aggregates of decanoic acid, their enantiomeric separation by liquid chromatography onto a (R)-1-naphthylglycine and 3,5-dinitrobenzoic acid stationary phase and quantification by tandem mass spectrometry. Limits of quantitation (LOQs) for NSAID enantiomers were in the range 1.7-3.3 ng g(-1). Absolute recoveries were from 97 to 104 %, which indicated the high extraction efficiency of the supramolecular solvent. Extraction equilibrium conditions were reached after 10 min which permitted fast sample treatment. Relative standard deviations for enantiomers in fish muscle were always below 6 %. Isotopically labelled internal standards were used to compensate for matrix interferences. The method in-house validation was carried out with the Oncorhynchus mykiss species, and it was applied to the determination of NSAID enantiomers in different fortified freshwater fish species (Alburnus alburnus, Lepomis gibbosus, Micropterus salmoides, O. mykiss and Cyprinus carpio). PMID:25869485

  6. Gene Flow and Maintenance of Genetic Diversity in Invasive Mosquitofish (Gambusia holbrooki)

    PubMed Central

    Díez-del-Molino, David; Carmona-Catot, Gerard; Araguas, Rosa-Maria; Vidal, Oriol; Sanz, Nuria; García-Berthou, Emili; García-Marín, Jose-Luis

    2013-01-01

    Genetic analyses contribute to studies of biological invasions by mapping the origin and dispersal patterns of invasive species occupying new territories. Using microsatellite loci, we assessed the genetic diversity and spatial population structure of mosquitofish (Gambusia holbrooki) that had invaded Spanish watersheds, along with the American locations close to the suspected potential source populations. Mosquitofish populations from the Spanish streams that were studied had similar levels of genetic diversity to the American samples; therefore, these populations did not appear to have undergone substantial losses of genetic diversity during the invasion process. Population structure analyses indicated that the Spanish populations fell into four main clusters, which were primarily associated with hydrography. Dispersal patterns indicated that local populations were highly connected upstream and downstream through active dispersal, with an average of 21.5% fish from other locations in each population. After initially introducing fish to one location in a given basin, such dispersal potential might contribute to the spread and colonization of suitable habitats throughout the entire river basin. The two-dimension isolation-by-distance pattern here obtained, indicated that the human-mediated translocation of mosquitofish among the three study basins is a regular occurrence. Overall, both phenomena, high natural dispersal and human translocation, favor gene flow among river basins and the retention of high genetic diversity, which might help retain the invasive potential of mosquitofish populations. PMID:24358194

  7. Ecotoxicities of polyquaterniums and their associated polyelectrolyte-surfactant aggregates (PSA) to Gambusia holbrooki.

    PubMed

    Cumming, Janet L; Hawker, Darryl W; Nugent, Kerry W; Chapman, Heather F

    2008-02-01

    The toxicity of 11 polyquaterniums used in cosmetic applications, and polydimethyldiallylammonium chloride (poly(DADMAC)) were studied for toxicity of the polyquaternium alone, and of a polyquaternium/anionic surfactant complex as occurs in some cosmetic formulations. The surfactant used in the study was sodium dodecyl sulfate (SDS), which is used in cosmetic formulations under its International Nomenclature of Cosmetic Ingredients (INCI) name Sodium Laurel Sulfate. In fish immobilization studies with Gambusia holbrooki, the EC(50) of the polyquaternium/surfactant complex was found to be the same as or similar to the EC(50) for the polyquaternium alone. The toxicity of the polyquaterniums investigated was similar to the published values for other cationic polyelectrolytes and cationic surfactants, in the range from < 1.0 to 10 mg/L, with the exception of low charge density cellulosic polyquaterniums. The anionic surfactant alone was not toxic to fish in the concentration range tested. Results thus showed the toxicity of the polyquaternium was not mitigated by the presence of the anionic surfactant. PMID:18172802

  8. Laboratory and field validation of a simple method for detecting four species of non-native freshwater fish using eDNA.

    PubMed

    Davison, P I; Créach, V; Liang, W-J; Andreou, D; Britton, J R; Copp, G H

    2016-09-01

    This paper presents the first phase in the development and validation of a simple and reliable environmental (e)DNA method using conventional PCR to detect four species of non-native freshwater fish: pumpkinseed Lepomis gibbosus, sunbleak Leucaspius delineatus, fathead minnow Pimephales promelas and topmouth gudgeon Pseudorasbora parva. The efficacy of the approach was demonstrated in indoor tank (44 l) trials in which all four species were detected within 24 h. Validation was through two field trials, in which L. gibbosus was detected 6-12 h after its introduction into outdoor experimental ponds and P. parva was successfully detected in disused fish rearing ponds where the species was known to exist. Thus, the filtration of small (30 ml) volumes of pond water was sufficient to capture fish eDNA and the approach emphasised the importance of taking multiple water samples of sufficient spatial coverage for detecting species of random or patchy distribution. PMID:27465299

  9. Reconciling patterns of genetic variation with stream structure, earth history and biology in the Australian freshwater fish Craterocephalus stercusmuscarum (Atherinidae).

    PubMed

    McGlashan, D J; Hughes, J M

    2000-11-01

    We examined the consequences of barriers, stream architecture and putative dispersal capability on levels of genetic differentiation among populations of the freshwater fish Craterocephalus stercusmuscarum. Seven polymorphic allozyme loci and sequences of a 498-bp fragment of the ATPase 6 mitochondrial DNA (mtDNA) gene were used to assess patterns of genetic variation among 16 populations from upland and lowland streams of five drainages in northern Queensland, Australia. Concordant patterns at both genetic markers revealed that there were significant levels of genetic subdivision among all populations, while an analysis of molecular variation showed that the distribution of genetic diversity was not consistent with contemporary drainage structure. There were reciprocally monophyletic mtDNA clades and fixed or large frequency differences at allozyme loci either side of instream barriers such as waterfalls. This implied barriers were effective in restricting gene flow between upland and lowland populations separated by waterfalls. However, there were two genetically distinct groups in upland areas, even within the same subcatchment, as well as high levels of genetic subdivision among lowland populations, suggesting barriers alone do not explain the patterns of genetic diversity. The data revealed a complex phylogeographic pattern, which we interpreted to be the result of one or more invasion events of independent lineages to different sections of each drainage, possibly mediated by well documented geomorphological changes. Our results highlight the importance of earth structure and history in shaping population genetic structure in stream organisms where dispersal capability may be limited, and reveal that the contemporary structure of drainages is not necessarily a good indicator of genetic relationships among populations. PMID:11091310

  10. Evaluating the effects of laboratory protocols on eDNA detection probability for an endangered freshwater fish.

    PubMed

    Piggott, Maxine P

    2016-05-01

    The effectiveness and accuracy of detection using environmental DNA (eDNA) is dependent on understanding the influence laboratory methods such as DNA extraction and PCR strategies have on detection probability. Ideally choice of sampling and extraction method will maximize eDNA yield and detection probability. Determining the survey effort required to reach a satisfactory detection probability (via increased PCR replicates or more sampling) could compensate for a lower eDNA yield if the sampling and extraction method has other advantages for a study, species or system. I analysed the effect of three different sampling and extraction methods on eDNA yield, detection probability and PCR replication for detecting the endangered freshwater fish Macquaria australasica from water samples. The impact of eDNA concentration, PCR strategy, target amplicon size and two marker regions: 12S (a mitochondrial gene) and 18S (a nuclear gene) was also assessed. The choice of sampling and extraction method and PCR strategy, rather than amplicon size and marker region, had the biggest effect on detection probability and PCR replication. The PCR replication effort required to achieve a detection probability of 0.95, ranged from 2 to 6 PCR replicates depending on the laboratory method used. As all methods yielded eDNA from which M. australasica was detected using the three target amplicons, differences in eDNA yield and detection probability between the three methods could be mitigated by determining the appropriate PCR replication effort. Evaluating the effect sampling and extraction methods will have on the detection probability and determining the laboratory protocols and PCR replication required to maximize detection and minimize false positives and negatives is a useful first step for eDNA occupancy studies. PMID:27066248

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

    USGS Publications Warehouse

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

    2009-01-01

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

  12. Organochlorine residues and elemental contaminants in U.S. freshwater fish, 1976-1986: National Contaminant Biomonitoring Program.

    PubMed

    Schmitt, C J; Zajicek, J L; May, T W; Cowman, D F

    1999-01-01

    As part of the National Contaminant Biomonitoring Program (NCBP, formerly a component of the National Pesticide Monitoring Program), the U.S. Fish and Wildlife Service periodically determined concentrations of organochlorine chemical residues and elemental contaminants in freshwater fish collected from a nationwide network of stations. In late 1986 and early 1987, the last time the network was sampled, a total of 319 composite fish samples were collected from 97 NCBP stations. The samples were analyzed for residues of organochlorine chemicals and the elements As, Cd, Cu, Hg, Pb, Se, and Zn. The mean concentration of total DDT and its homologs (p,p'-constituents) declined from 1984 to 1986, thus continuing a trend that began in 1970. The most persistent DDT homolog (p,p'-DDE) was detected at all stations sampled in 1986, and averaged 74% of total DDT residues, up from 70% in 1974-1979 but essentially unchanged from 1984. Collectively, these findings indicated a low rate of influx and continued weathering of DDT in the environment; nevertheless, DDT concentrations in fish from some stations in the South remained high enough to constitute a threat to piscivorous wildlife. Residues of polychlorinated biphenyls (PCBs) also remained widespread, but a significant downward trend in total PCB concentrations and incidence was evident, and PCB mixtures containing early eluting components were present at fewer stations than in the past. PCB concentrations were generally highest in fish from the industrialized rivers of the Northeast and Midwest and from the Great Lakes. Concentrations of toxaphene also declined, as did its incidence, from 88% of the stations sampled in 1980-1981 to 64% in 1986; however, analytical problems with the 1986 samples may have contributed to the latter. The risks represented by PCBs and toxaphene could not be evaluated on the basis of our data. Among cyclodiene insecticides, dieldrin and chlordane-related residues were the most widespread. Mean

  13. Phylogeography, historical demography and habitat suitability modelling of freshwater fishes inhabiting seasonally fluctuating Mediterranean river systems: a case study using the Iberian cyprinid Squalius valentinus.

    PubMed

    Perea, S; Doadrio, I

    2015-07-01

    The Mediterranean freshwater fish fauna has evolved under constraints imposed by the seasonal weather/hydrological patterns that define the Mediterranean climate. These conditions have influenced the genetic and demographic structure of aquatic communities since their origins in the Mid-Pliocene. Freshwater species in Mediterranean-type climates will likely constitute genetically well-differentiated populations, to varying extents depending on basin size, as a consequence of fragmentation resulting from drought/flood cycles. We developed an integrative framework to study the spatial patterns in genetic diversity, demographic trends, habitat suitability modelling and landscape genetics, to evaluate the evolutionary response of Mediterranean-type freshwater fish to seasonal fluctuations in weather. To test this evolutionary response, the model species used was Squalius valentinus, an endemic cyprinid of the Spanish Levantine area, where seasonal weather fluctuations are extreme, although our findings may be extrapolated to other Mediterranean-type species. Our results underscore the significant role of the Mediterranean climate, along with Pleistocene glaciations, in diversification of S. valentinus. We found higher nuclear diversity in larger drainage basins, but higher mitochondrial diversity correlated to habitat suitability rather than basin size. We also found strong correlation between genetic structure and climatic factors associated with Mediterranean seasonality. Demographic and migration analyses suggested population expansion during glacial periods that also contributed to the current genetic structure of S. valentinus populations. The inferred models support the significant contribution of precipitation and temperature to S. valentinus habitat suitability and allow recognizing areas of habitat stability. We highlight the importance of stable habitat conditions, fostered by typical karstic springs found on the Mediterranean littoral coasts, for the

  14. Occurrence of a novel acetylated amino acid, N(alpha)-acetylhistidine, in skeletal muscle of freshwater fish and other ectothermic vertebrates.

    PubMed

    Yamada, Shoji; Kawashima, Kazuto; Baba, Kyoko; Oku, Takahiro; Ando, Seiichi

    2009-03-01

    The occurrence of N(alpha)-acetylhistidine (NAH) in skeletal muscle of 91 species of freshwater fish and 9 species of other ectothermic vertebrates was investigated, with consideration of phylogenetic relationships. Of the 91 freshwater fish species examined, 13 species (7 cichlids, 5 anabantids, and 1 catfish) contained considerable amounts (>1 micromol/g) of NAH in their skeletal muscles. The highest level (10.37 micromol/g) of NAH was found in the tissue of Betta splendens (Siamese fighting fish). Moreover, the NAH contents in the tissues of Trichogaster trichopterus (three spot gourami), Kryptopterus bicirrhis (glass catfish), Oreochromis niloticus (Nile tilapia), Mikrogeophagus ramirezi (ram cichlid) and Parachromis managuensis (Guapote tigre) were 3.17-6.16 micromol/g. The skeletal muscle of amphibians (5 species) and reptiles (4 species) had a low level (<0.25 micromol/g) of NAH. The present findings clearly demonstrate NAH as the fifth imidazole-related compound, in addition to histidine, carnosine, anserine and ophidine (balenine), recognized as a major non-protein nitrogenous constituent in the skeletal muscle of vertebrate animals. PMID:19100335

  15. Toxicity of the Herbicide Atrazine: Effects on Lipid Peroxidation and Activities of Antioxidant Enzymes in the Freshwater Fish Channa Punctatus (Bloch)

    PubMed Central

    Nwani, Christopher Ddidigwu; Lakra, Wazir Singh; Nagpure, Naresh Sahebrao; Kumar, Ravindra; Kushwaha, Basdeo; Srivastava, Satish Kumar

    2010-01-01

    The present study was undertaken to evaluate the toxicity and effects of a commercial formulation of the herbicide atrazine (Rasayanzine) on lipid peroxidation and antioxidant enzyme system in the freshwater air breathing fish Channa punctatus. The 12, 24, 48, 72 and 96 h LC50 of atrazine, calculated by probit analysis, were determined to be 77.091, 64.053, 49.100, 44.412 and 42.381 mg·L−1, respectively, in a semi static system with significant difference (p < 0.05) in LC10–90 values obtained for different times of exposure. In addition to concentration and time dependent decrease in mortality rate, stress signs in the form of behavioral changes were also observed in response to the test chemical. In fish exposed for 15 days to different sublethal concentrations of the herbicide (1/4 LC50 = ∼10.600 mg·L−1, 1/8 LC50 = ∼5.300 mg·L−1 and 1/10 LC50 = ∼4.238 mg·L−1) induction of oxidative stress in the liver was evidence by increased lipid peroxidation levels. The antioxidants superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) responded positively in a concentration dependent pattern, thus, suggesting the use of these antioxidants as potential biomarkers of toxicity associated with contaminations exposure in freshwater fishes. PMID:20948961

  16. SIMULTANEOUS MULTIPLE SPECIES TESTING: ACUTE TOXICITY OF 13 CHEMICALS TO 12 DIVERSE FRESHWATER AMPHIBIAN, FISH, AND INVERTEBRATE FAMILIES

    EPA Science Inventory

    The test series developed methods for testing a compliment of aquatic organisms in a single test that satisfies the freshwater acute toxicity requirements for setting water quality criteria. Species tested included fathead minnows Pimephales promelas, rainbow trout Salmo gairdner...

  17. Site-specific water quality criteria for lethal/sublethal protection of freshwater fish exposed to zinc in southern Taiwan.

    PubMed

    Chen, Wei-Yu; Chen, Tzu-Yin; Hsieh, Nan-Hung; Ju, Yi-Ting

    2016-09-01

    There were considerable concerns about the zinc (Zn) pollution caused by electroplating, chemical, and computer-related high-tech industrial discharges in Kaohsiung Rivers situated at south Taiwan. There is, however, a lack of site-specific water chemistry based toxicity assessment and little is known about the sublethal toxicity on freshwater fish. This study proposes an integrated framework to link experimental and mechanistic model-based data analysis of lethal and sublethal Zn toxicities for grass carp (Ctenopharyn odon idellus) populations for providing the site-specific Zn water quality threshold in Kaohsiung Rivers. A biotic ligand model (BLM) that relates toxicity impairment of physiological active sites impacted by Zn species was used to elucidate the site-specific water chemistry affecting the bioavailability and biological response of grass carp exposed to Zn. Results indicated that 96-h LC50 for mortality and 28-d EC50 for growth inhibition were 474.7 ± 1.3 (mean ± SE) and 149 ± 23.5 μg L(-1), respectively. Here the BLM-based predicted steady-state LC50s for mortality were 2110.7, 818.2, 1303.6, 563.3, and 497.1 μg L(-1), whereas measured steady-state EC50s for growth inhibition were 726.8, 326.2, 373.4, 193.9, and 170.5 μg L(-1) for the Agongdian, Houling, Love, Fengshan, and Gaoping Rivers, respectively. A positive correlation between Mg(2+) and EC50 values were found in both acute (r = 0.94, p < 0.01) and chronic (r = 0.97, p < 0.01) Zn exposures. This study suggests that the use of site-specific water chemistry data and ecophysiological traits would enhance the predictive capacities to assess the potential effect of metal toxicity posed to aquatic organisms. PMID:27337432

  18. Effects of Roundup formulations, nutrient addition, and Western mosquitofish (Gambusia affinis) on aquatic communities.

    PubMed

    Geyer, Rebecca L; Smith, Geoffrey R; Rettig, Jessica E

    2016-06-01

    Aquatic communities can be affected by herbicides, nutrient addition, and non-native fish species. We conducted a mesocosm experiment to examine the direct and interactive effects of three stressors: (1) Roundup formulations (Roundup Weed and Grass Killer(®) and Roundup Poison Ivy and Tough Brush Killer Plus(®)), (2) nutrient addition, and (3) the presence of the non-native Western mosquitofish (Gambusia affinis), on experimental pond communities. Roundup formulations had the most widespread effects on the zooplankton community, but effects varied between formulations and among taxa. The only significant effect of nutrient addition was a lowering of Daphnia abundance in the nutrient addition treatments. The abundances of Daphnia, mid-sized cladocerans, and total zooplankton were lowered by mosquitofish, but no other taxa showed significant mosquitofish effects. We found several two-way and three-way interactions among the stressors, but these varied among zooplankton taxa. Chlorophyll a levels were higher with nutrient addition but were not significantly affected by Roundup formulation or mosquitofish. Our results suggest toxicity of Roundup formulations varies among taxa, and Roundup formulations differ in their toxicity to zooplankton, but with no cascading effects on primary producers. In addition, interactions among stressors affected the zooplankton community. PMID:26944427

  19. Telomeric attrition with age and temperature in Eastern mosquitofish ( Gambusia holbrooki)

    NASA Astrophysics Data System (ADS)

    Rollings, Nicky; Miller, Emily; Olsson, Mats

    2014-03-01

    Telomeric attrition has repeatedly been found to correlate with the ageing of organisms; however, recent research is increasingly showing that the determinants of attrition dynamics are not well understood. This study examined the relative telomere lengths in Eastern mosquitofish, Gambusia holbrooki, kept at different temperatures and at different ages. Newly born fry were randomly selected for one of four treatment groups: 20, 30, 20-30, and 30-20 °C, where the third and fourth treatment groups were gradually changed from their starting temperature to their final temperature between days 10 and 14. Telomere length was measured, and it was found that length decreased with age and that fish exposed to the 20 °C treatment had significantly shorter telomeres than those that received the 30-20 °C treatment. Telomeric attrition with age agrees with results previously found in studies of telomeres; however, the variation in attrition with temperature was not simply predictable and may be the synergistic effects of temperature and some other factor.

  20. Feminization and masculinization of western mosquitofish (Gambusia affinis) observed in rivers impacted by municipal wastewaters

    PubMed Central

    Huang, Guo-Yong; Liu, You-Sheng; Chen, Xiao-Wen; Liang, Yan-Qiu; Liu, Shuang-Shuang; Yang, Yuan-Yuan; Hu, Li-Xin; Shi, Wen-Jun; Tian, Fei; Zhao, Jian-Liang; Chen, Jun; Ying, Guang-Guo

    2016-01-01

    Municipal wastewaters have been known to contain various estrogens and androgens. Little is known about the joint action of these chemicals from wastewaters on fishes in the aquatic environment. The objectives of this study were to investigate the estrogenic and/or androgenic effects in wild mosquitofish (Gambusia affinis) of two effluent-impacted rivers in South China by determining morphological changes and hepatic mRNA expression levels of relevant genes such as vitellogenin (Vtg), estrogen receptor (ERα) and androgen receptors (ARα and ARβ), and to assess the linkages of those morphological changes and hepatic mRNA expression levels to the chemical concentrations measured by in vitro bioassays and chemical analysis. The results showed a significant induction of Vtg and ERα mRNA in the livers of the males and a gonopodium-like anal fin in the females collected at the majority of sites. Redundancy analysis and Pearson correlation analysis showed that the chemical concentrations obtained by in vitro bioassays and chemical analysis had significant correlations with some of the endpoints for the estrogenic and/or androgenic effects in mosquitofish. The findings from this study indicate that the estrogens and androgens present in the two rivers could cause the observed estrogenic and androgenic effects in mosquitofish. PMID:26876344

  1. Acute toxicity of mosquitocidal compounds to young mosquitofish, Gambusia affinis.

    PubMed

    Tietze, N S; Hester, P G; Hallmon, C F; Olson, M A; Shaffer, K R

    1991-06-01

    Toxicity of Florida mosquito larvicides and adulticides to 3-5 day old Gambusia affinis was determined in the laboratory. After 24-h exposure, the larvicides, temephos, fenoxycarb and petroleum distillates had LC50 values of 5.60, 1.05 and 593.4 ppm, respectively. After 24 h the adulticides resmethrin, fenthion, naled and malathion had LC50 values of 0.007, 2.94, 3.50 and 12.68 ppm, respectively. The only compound toxic to young mosquitofish at maximum field application rates was resmethrin. However, in the light of earlier tests, aerially applied adulticides generally reach the water surface at reduced concentrations and thus probably pose little or no risk to mosquitofish populations. PMID:1716659

  2. Effects of herbal essential oils used to extend the shelf life of freshwater-reared Asian sea bass fish (Lates calcarifer).

    PubMed

    Harpaz, S; Glatman, L; Drabkin, V; Gelman, A

    2003-03-01

    Sensory and microbiological characteristics of Asian sea bass (Lates calcarifer) fish raised in a freshwater pond were evaluated during cold storage for 33 days. Whole fish (averaging 400 g each) were stored in a cold storage room at 0 to 2 degrees C. Essential oils of herbs--thyme (Thymus vulgaris) and oregano (Origanum vulgare)--added at 0.05% (vol/vol) were used as preservatives. On the basis of the sensory test results as well as the bacteriological tests, the addition of oregano and thyme essential oils can considerably slow the process of spoilage. The fish treated with these oils were still fit for human consumption after 33 days of storage. The results obtained through sensory tests are corroborated to a great extent by the chemical (hypoxanthine) tests and to a lesser extent by the physical (Cosmos units) tests. The initial total bacteriological counts were 1.7 x 10(3) CFU/cm2 on the fish surface and <10(2) CFU/g in the fish flesh, and in the control treatment (without preservatives), these counts rose continuously, reaching around 10(7) CFU/cm2 on the fish surface and 10(3) CFU/g in the flesh after 33 days of storage at 0 to 2 degrees C. The use of herbal essential oils as preservatives, on the other hand, resulted in a maximal count of 10(5) CFU/cm2 on the fish surface, while the bacterial count in the flesh remained <10(2) CFU/g by the end of the 33-day storage period at 0 to 2 degrees C. PMID:12636293

  3. Ecological risk assessment of silicon dioxide nanoparticles in a freshwater fish Labeo rohita: Hematology, ionoregulation and gill Na(+)/K(+) ATPase activity.

    PubMed

    Krishna Priya, K; Ramesh, M; Saravanan, M; Ponpandian, N

    2015-10-01

    The fate and effect of nanomaterials in the environment has raised concern about their environmental risk to aquatic organisms. Silica nanoparticles (SiO2-NPs) find its uses in various fields and are inevitably released into the environment. However, the ecotoxicological effects of SiO2-NPs on the freshwater fish remain poorly understood. The aim of this study was to evaluate the effect of different concentrations (1, 5 and 25mgL(-1)) of SiO2-NPs on certain hematological, ionoregulatory and enzymological profiles of a freshwater teleost fish Labeo rohita. Hematological parameters such as hemoglobin (Hb), hematocrit (Hct), red blood cells (RBC), white blood cells (WBC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) values were altered in SiO2-NPs treated groups. Likewise, plasma electrolytes such as plasma sodium (Na(+)), potassium (K(+)) and chloride (Cl(-)) levels and Na(+)/K(+) ATPase activity in gill of SiO2-NPs treated groups were altered in all concentrations throughout the study period (96h). The alterations of these parameters were found to be dependent on dose and exposure period. The results of the present study indicate that the alterations of these parameters may relate to physiological stress system to SiO2-NPs toxicity and also demonstrate that manufactured metal oxide NPs in aquatic environment may affect the health condition of the aquatic organisms. PMID:26094035

  4. Occurrence of Trichodinid Ciliophorans (Ciliophora: Peritrichida) in the freshwater fishes of the river Churni with description of Trichodina glossogobae sp. nov. in West Bengal, India.

    PubMed

    Mitra, Amlan Kumar; Bandyopadhyay, Probir K; Gong, Yingchun; Bhowmik, Biplab

    2012-04-01

    Between January 2011 and March 2011 occurrence of trichodinid ciliophorans were studied in the freshwater fishes of the river Churni. The biodiversity survey revealed presence of a new species of the genus Trichodina (Ehrenberg 1830) infesting Glossogobius giuris (Hamilton-Buchanan). Another freshwater fish Labeo bata (Hamilton 1822) were found to be infested with two species of the genus Tripartiella Lom 1959: Tripartiella bulbosa (Davis 1947) Lom 1959 and T. copiosa Lom 1959. Adhesive disc size of the new Trichodina species is small measuring 30.6-46.9 (36.2 ± 3.9) μm in diameter. The centre of the disc is finely granular and transforms into dark when impregnated with silver. The overall prevalence of this species is 15.6% (12/77). Tripartiella bulbosa and T. copiosa are very small sized ciliophorans, measuring 16.7-23.8 (20.6 ± 2.2) μm and 15.2-22.4 (19.7 ± 1.9) μm in diameter, respectively. PMID:23542238

  5. Distribution of brominated flame retardants and dechloranes between sediments and benthic fish--A comparison of a freshwater and marine habitat.

    PubMed

    Sühring, Roxana; Busch, Friederike; Fricke, Nicolai; Kötke, Danijela; Wolschke, Hendrik; Ebinghaus, Ralf

    2016-01-15

    A total of 53 halogenated flame retardants (HFRs) were analysed in sediments, European eels and dabs from both freshwater and marine sampling stations in the German Bight and the river Elbe. Classic HFRs, such as polybrominated diphenylethers (PBDEs), were the highest concentrated HFRs in eels as well as in most dabs (apart from 1,2,5,6-tetrabromocyclooctane (TBCO)). In sediments, on the other hand, alternate BFRs and especially dechloranes dominated the contamination pattern. Dabs were still found to be statistically representative for the contamination patterns and relative magnitude in sediments from their respective habitats. Contamination patterns in eels seemed to be more driven by the contamination situation in the food chain or historical contamination of their habitat. Unsuspectedly the alternate flame retardant TBCO was found in comparably high concentrations (up to 12 ng g(-1) ww) in dabs from two sampling stations as well as in sediments from these stations (up to 1.2 ng g(-1) dw). It could not be detected in any other analysed fish or sediment samples, indicating a localised contamination source in the area. This study provides information on HFR contamination patterns and behaviour in both marine and freshwater sediments and their potential role as contamination source for benthic fish. PMID:26544886

  6. Spatial and temporal patterns of mercury concentrations in freshwater fish across the Western United States and Canada.

    PubMed

    Eagles-Smith, Collin A; Ackerman, Joshua T; Willacker, James J; Tate, Michael T; Lutz, Michelle A; Fleck, Jacob A; Stewart, A Robin; Wiener, James G; Evers, David C; Lepak, Jesse M; Davis, Jay A; Pritz, Colleen Flanagan

    2016-10-15

    Methylmercury contamination of fish is a global threat to environmental health. Mercury (Hg) monitoring programs are valuable for generating data that can be compiled for spatially broad syntheses to identify emergent ecosystem properties that influence fish Hg bioaccumulation. Fish total Hg (THg) concentrations were evaluated across the Western United States (US) and Canada, a region defined by extreme gradients in habitat structure and water management. A database was compiled with THg concentrations in 96,310 fish that comprised 206 species from 4262 locations, and used to evaluate the spatial distribution of fish THg across the region and effects of species, foraging guilds, habitats, and ecoregions. Areas of elevated THg exposure were identified by developing a relativized estimate of fish mercury concentrations at a watershed scale that accounted for the variability associated with fish species, fish size, and site effects. THg concentrations in fish muscle ranged between 0.001 and 28.4 (μg/g wet weight (ww)) with a geometric mean of 0.17. Overall, 30% of individual fish samples and 17% of means by location exceeded the 0.30μg/g ww US EPA fish tissue criterion. Fish THg concentrations differed among habitat types, with riverine habitats consistently higher than lacustrine habitats. Importantly, fish THg concentrations were not correlated with sediment THg concentrations at a watershed scale, but were weakly correlated with sediment MeHg concentrations, suggesting that factors influencing MeHg production may be more important than inorganic Hg loading for determining fish MeHg exposure. There was large heterogeneity in fish THg concentrations across the landscape; THg concentrations were generally higher in semi-arid and arid regions such as the Great Basin and Desert Southwest, than in temperate forests. Results suggest that fish mercury exposure is widespread throughout Western US and Canada, and that species, habitat type, and region play an important

  7. A survey of coccidian infections of freshwater fishes of Peninsular Malaysia, with descriptions of three species of Goussia Labbé, 1896 (Apicomplexa: Eimeriidae).

    PubMed

    Molnár, K; Shaharom-Harrison, F; Székely, Cs

    2003-05-01

    Ninety-five specimens of 14 freshwater fish species from small streams in the Kuala Terengganu district and the Lake Kenyir Reservoir, Malaysia, were surveyed for coccidian infections. Six fish species proved to be infected with apicomplexans belonging to the genus Goussia. In all of these fishes Goussia species were found in unsporulated and semisporulated stages. Oöcysts of four species inhabiting the intestinal epithelium became sporulated in tap-water within 24 hours. In two fish species sporulation failed and only unsporulated oöcysts were recorded in the intestine. Three of the intestinal species finishing sporulation proved to be new to science and were described as Goussia malayensis n. sp., G. bettae n. sp. and G. pogonognathi n. sp. from Apocheilus panchax, Betta splendens and Hemirhamphodon pogonognatus, respectively. The fourth species, found in Trichogaster pectoralis, was identified as G. trichogasteri Székely & Molnár, 1992, a species known from aquarium-cultured T. trichopterus. PMID:12815211

  8. Metals (Ag(+) , Cd(2+) , Cr(6+) ) affect ATPase activity in the gill, kidney, and muscle of freshwater fish Oreochromis niloticus following acute and chronic exposures.

    PubMed

    Atli, Gülüzar; Canli, Mustdafa

    2013-12-01

    Freshwater fish Oreochromis niloticus were individually acutely exposed to different concentrations (0, 0.1, 0.5, 1.0, and 1.5 μg/mL) of Cd(2+) , Cr(6+) , and Ag(+) for 96 h and 0.05 μg/mL concentration of the same metals for different periods (0, 5, 10, 20, and 30 days) chronically. Following each experimental protocol, Na(+) /K(+) -ATPase, Mg(2+) -ATPase, and Ca(2+) -ATPase activities were measured in the gill, kidney, and muscle of O. niloticus. In vitro experiments were also performed to determine the direct effects of metal ions (0, 0.1, 0.5, 1.0, and 1.5 μg/mL) on ATPases. Except Ag(+) , none of the metals caused fish mortality within 30 days. Silver killed all the fishes within 16 days. Metal exposures generally decreased Na(+) /K(+) -ATPase and Ca(2+) -ATPase activities in the tissues of O. niloticus, although there were some fluctuations in Mg(2+) -ATPase activity. Ag(+) and Cd(2+) were found to be more toxic to ATPase activities than Cr(6+) . It was also observed that metal efficiency was higher in the gill than in the other tissues. Results indicated that the response of ATPases varied depending on metals, exposure types, and tissues. Because ATPases are sensitive to metal toxicity, their activity can give valuable data about fish physiology. Therefore, they may be used as a sensitive biomarker in environmental monitoring in contaminated waters. PMID:21901811

  9. The effects of laboratory housing and spatial enrichment on brain size and metabolic rate in the eastern mosquitofish, Gambusia holbrooki

    PubMed Central

    Turschwell, Mischa P.; White, Craig R.

    2016-01-01

    ABSTRACT It has long been hypothesised that there is a functional correlation between brain size and metabolic rate in vertebrates. The present study tested this hypothesis in wild-caught adult mosquitofish Gambusia holbrooki by testing for an intra-specific association between resting metabolic rate (RMR) and brain size while controlling for variation in body size, and through the examination of the effects of spatial enrichment and laboratory housing on body mass-independent measures of brain size and RMR. Controlling for body mass, there was no relationship between brain size and RMR in wild-caught fish. Contrary to predictions, spatial enrichment caused a decrease in mass-independent brain size, highlighting phenotypic plasticity in the adult brain. As expected, after controlling for differences in body size, wild-caught fish had relatively larger brains than fish that had been maintained in the laboratory for a minimum of six weeks, but wild-caught fish also had significantly lower mass-independent RMR. This study demonstrates that an organisms' housing environment can cause significant plastic changes to fitness related traits including brain size and RMR. We therefore conclude that current standard laboratory housing conditions may cause captive animals to be non-representative of their wild counterparts, potentially undermining the transferability of previous laboratory-based studies of aquatic ectothermic vertebrates to wild populations. PMID:26794608

  10. The effects of laboratory housing and spatial enrichment on brain size and metabolic rate in the eastern mosquitofish, Gambusia holbrooki.

    PubMed

    Turschwell, Mischa P; White, Craig R

    2016-01-01

    It has long been hypothesised that there is a functional correlation between brain size and metabolic rate in vertebrates. The present study tested this hypothesis in wild-caught adult mosquitofish Gambusia holbrooki by testing for an intra-specific association between resting metabolic rate (RMR) and brain size while controlling for variation in body size, and through the examination of the effects of spatial enrichment and laboratory housing on body mass-independent measures of brain size and RMR. Controlling for body mass, there was no relationship between brain size and RMR in wild-caught fish. Contrary to predictions, spatial enrichment caused a decrease in mass-independent brain size, highlighting phenotypic plasticity in the adult brain. As expected, after controlling for differences in body size, wild-caught fish had relatively larger brains than fish that had been maintained in the laboratory for a minimum of six weeks, but wild-caught fish also had significantly lower mass-independent RMR. This study demonstrates that an organisms' housing environment can cause significant plastic changes to fitness related traits including brain size and RMR. We therefore conclude that current standard laboratory housing conditions may cause captive animals to be non-representative of their wild counterparts, potentially undermining the transferability of previous laboratory-based studies of aquatic ectothermic vertebrates to wild populations. PMID:26794608

  11. Laboratory evaluation of the predation efficacy of native Australian fish on Culex annulirostris (Diptera: Culicidae).

    PubMed

    Hurst, Timothy P; Brown, Michael D; Kay, Brian H

    2004-09-01

    The introduction and establishment of fish populations can provide long-term, cost-effective mosquito control in habitats such as constructed wetlands and ornamental lakes. The predation efficacy of 7 native Brisbane freshwater fish on 1st and 4th instars of the freshwater arbovirus vector Culex annulirostris was evaluated in a series of 24-h laboratory trials. The trials were conducted in 30-liter plastic carboys at 25+/-1 degrees C under a light:dark cycle of 14:10 h. The predation efficacy of native crimson-spotted rainbowfish Melanotaenia duboulayi (Melanotaeniidae), Australian smelt Retropinna semoni (Retropinnadae), Pacific blue-eye Pseudomugil signifer (Atherinidae), fly-specked hardyhead Craterocephalus stercusmuscarum (Atherinidae), firetail gudgeon Hypseleotris galii (Eleotridae), empire gudgeon Hypseleotris compressa (Eleotridae), and estuary perchlet Ambassis marianus (Ambassidae) was compared with the exotic eastern mosquitofish Gambusia holbrooki (Poeciliidae). This environmentally damaging exotic has been disseminated worldwide and has been declared noxious in Queensland. Melanotaenia duboulayi was found to consume the greatest numbers of both 1st and 4th instars of Cx. annulirostris. The predation efficacy of the remaining Australian native species was comparable with that of the exotic G. holbrooki. With the exception of A. marianus, the maximum predation rates of these native species were not statistically different whether tested individually or in a school of 6. Based on these data, M. duboulayi, H. compressa, and A. marianus warrant further investigation as biological control agents in pilot field trials. PMID:15532929

  12. Shifts in stable-isotope signatures confirm parasitic relationship of freshwater mussel glochidia attached to host fish

    USGS Publications Warehouse

    Fritts, Mark W.; Fritts, Andrea K.; Carleton, Scott A.; Bringolf, Robert B.

    2013-01-01

    The parasitic nature of the association between glochidia of unionoidean bivalves and their host fish (i.e. the role of fish hosts in providing nutritional resources to the developing glochidia) is still uncertain. While previous work has provided descriptions of development of glochidia on fish hosts, earlier studies have not explicitly documented the flow of nutrition from the host fish to the juvenile mussel. Therefore, our objective was to use stable isotope analysis to quantitatively document nutrient flow between fish and glochidia. Glochidia were collected from nine adult Lampsilis cardium and used to inoculate Micropterus salmoides(n = 27; three fish per maternal mussel) that produced juvenile mussels for the experiment. Adult mussel tissue samples, glochidia, transformed juvenile mussels and fish gill tissues were analysed for δ15N and δ13C isotope ratios. We used a linear mixing model to estimate the fraction of juvenile mussel tissue derived from the host fish's tissue during attachment. Our analyses indicate a distinct shift in both C and N isotopic ratios from the glochidial stage to the juvenile stage during mussel attachment and development. Linear mixing model analysis indicated that 57.4% of the δ15N in juvenile tissues were obtained from the host fish. This work provides novel evidence that larval unionoideans are true parasites that derive nutrition from host fish during their metamorphosis into the juvenile stage.

  13. The influence of environmental calcium concentrations on calcium flux, compensatory drinking and epithelial calcium channel expression in a freshwater cartilaginous fish.

    PubMed

    Allen, Peter J; Weihrauch, Dirk; Grandmaison, Vanessa; Dasiewicz, Patricia; Peake, Stephan J; Anderson, W Gary

    2011-03-15

    Calcium metabolism and mRNA levels of the epithelial calcium channel (ECaC) were examined in a freshwater cartilaginous fish, the lake sturgeon Acipenser fulvescens. Lake sturgeon were acclimated for ≥2 weeks to 0.1 (low), 0.4 (normal) or 3.3 (high) mmol l(-1) environmental calcium. Whole-body calcium flux was examined using (45)Ca as a radioactive marker. Net calcium flux was inward in all treatment groups; however, calcium influx was greatest in the low calcium environment and lowest in the high calcium environment, whereas efflux had the opposite relationship. A significant difference in the concentration of (45)Ca in the gastrointestinal tract (GIT) of fish in the low calcium environment led to the examination of drinking rate and calcium flux across the anterior-middle (mid) intestine. Drinking rate was not different between treatments; however, calcium influx across the mid-intestine in the low calcium treatment was significantly greater than that in both the normal and high calcium treatments. The lake sturgeon ECaC was 2831 bp in length, with a predicted protein sequence of 683 amino acids that shared a 66% identity with the closest sequenced ECaCs from the vertebrate phyla. ECaC mRNA levels were examined in the gills, kidney, pyloric caeca, mid-intestine and spiral intestine. Expression levels were highest in the gills, then the kidneys, and were orders of magnitude lower in the GIT. Contrary to existing models for calcium uptake in the teleost gill, ECaC expression was greatest in high calcium conditions and kidney ECaC expression was lowest in low calcium conditions, suggesting that cellular transport mechanisms for calcium may be distinctly different in these freshwater cartilaginous fishes. PMID:21346128

  14. Measured Mercury Contamination in Freshwater Fish in Rhode Island Compared with Predictions From a Regional Environmental Mercury Model

    EPA Science Inventory

    Edible tissue of largemouth bass collected at 29 freshwater sites across the variable landscape of Rhode Island, USA showed a 27 fold range in total mercury concentrations [Hg], from 0.04 to 1.0 ppm (wet). Twenty-one variables, including water quality data and geographic informat...

  15. Molecular evidence for the predation of Critically Endangered endemic Aphanius transgrediens from the stomach contents of world wide invasive Gambusia affinis.

    PubMed

    Keskin, Emre

    2016-01-01

    Predation and competition among native and invasive species are difficult to study in aquatic environments. Identification of preys from semi-digested body parts sampled from stomach contents of the predator is very challenging. Recent studies were mainly based on use of DNA extracted from stomach content to identify the prey species. This study presents the molecular evidence that reveals the predation of critically endangered Aphanius transgrediens by world-wide invasive Gambusia affinis for a better understanding of the link between the invasion and the extinction of native species in freshwater ecosystems. DNA samples were extracted from semi-digested stomach contents of the invader and short fragments of mitochondrial NADH1 gene were amplified using species-specific primers designed in this study to make identification at species level. Existence of both the prey and the predator species were also confirmed using environmental DNA extracted from water samples. PMID:25082451

  16. New nematode species, Orientatractis mekongensis n. sp. (Atractidae) and Neosynodontisia suratthaniensis n. g., n. sp. (Pharyngodonidae) from freshwater fishes in Thailand.

    PubMed

    Moravec, František; Kamchoo, Kanda; Pachanawan, Adithepchaikarn

    2015-11-01

    Based on light and scanning electron microscopical studies, two new species of nematode parasites are described from freshwater fishes in Thailand: Orientatractis mekongensis n. sp. (Atractidae) from the intestine of Pangasius bocourti Sauvage (type-host) and Helicophagus leptorhynchus Ng & Kottelat (both Pangasiidae, Siluriformes), and Neosynodontisia suratthaniensis n. sp. (Pharyngodonidae) from the intestine of Labiobarbus siamensis (Sauvage) (Cyprinidae, Cypriniformes), for which a new genus Neosynodontisia n. g. is established. Orientatractis mekongensis is mainly characterised by the number and distribution of caudal papillae (2 preanal, 1 adanal and 5 postanal pairs), the length of the left spicule (306-384 µm) and large body sizes (length of males and gravid females 5.4-6.7 mm and 7.8-9.0 mm, respectively). Neosynodontisia differs from other pharyngodonid genera with representatives parasitic in fishes not only by some morphological features (mouth withdrawn into the cephalic end with inflated cuticle, structure of the male caudal end, filamented eggs), but mainly by the occurrence of males inside the body of females. A key to the genera of the Pharyngodonidae with representatives parasitising fishes is provided. PMID:26446542

  17. Fermentative recovery of lipids and proteins from freshwater fish head waste with reference to antimicrobial and antioxidant properties of protein hydrolysate.

    PubMed

    Ruthu; Murthy, Pushpa S; Rai, Amit Kumar; Bhaskar, N

    2014-09-01

    Effectiveness of fermentation using lactic acid bacteria (LAB) for recovering lipids and proteins simultaneously from freshwater fish head (FWH) was evaluated. Three different proteolytic LAB (Pediococcus acidilactici NCIM5368, Enterococcus faecium NCIM5335 and Pediococcus acidilactici FD3) isolated from fish processing wastes were employed in the fermentation process. The fermentation conditions involved 10 % (w/w) glucose, 2 % (w/w) NaCl and 10 % (v/w) LAB cultures at 37 °C. The process resulted in 38.4 % of degree of hydrolysis (in case proteins) and a recovery of 63.6 % of the oil present in the material. The fermentation process did not affect the fatty acid profile of lipids. The hydrolyzed protein rich fermentation liquor exhibited DPPH radical scavenging activity (EC50 - 5.1 mg protein) as well as antagonistic properties towards several bacterial and fungal pathogens. The minimum inhibitory concentrations (MIC) of fermentated liquor (with E. faecium NCIM5335 as starter) were 10 and 12 mg/ml for Listeria monocytogenes and Salmonella itridicus, respectively. A higher MIC (60 and 96 mg/ml for Aspergillus ochraceus and Penicillium chrysogenum, respectively) was observed in case of fungal pathogens. Both the oil and protein hydrolysate rich liquor from fish head can be used as biofunctional ingredients in both human food as well as livestock feed formulations. PMID:25190843

  18. Distribution of polycyclic aromatic hydrocarbon (PAH) residues in several tissues of edible fishes from the largest freshwater lake in China, Poyang Lake, and associated human health risk assessment.

    PubMed

    Zhao, Zhonghua; Zhang, Lu; Cai, Yongjiu; Chen, Yuwei

    2014-06-01

    The residual levels, tissue distribution and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in edible fishes, bighead carp (Aristichthys nobilis) and silver carp (Hypophthalmichthys molitrix), from the largest freshwater lake in China, Poyang Lake, were studied. PAH concentrations ranged from 105 to 513ng g(-1)ww and from 53.9 to 401ng g(-1)ww in different tissues of bighead carp and silver carp, respectively. Low molecular weight (LMW) PAHs were the predominant compounds, suggesting the gill-water transfer might be the major exposure route for PAHs in the studied fish species. Tissue distribution indicated that the hepatobiliary system accumulated higher concentrations of PAHs than the extrahepatic tissues with bile being the most predominant tissue for both species. Composition analysis demonstrated that PAHs were from the combined petrogenic and pyrogenic origin, and the gasoline combustion might be the main source. A preliminary evaluation of human health risk using benzo[a]pyrene (BaP) potency equivalent concentration (PEC) as well as the incremental lifetime cancer risk (ILCR) indicated that PAHs in fish would induce potential carcinogenic effects. PMID:24732028

  19. Suitability of magnetic particle immunoassay for the analysis of PBDEs in Hawaiian freshwater fish and crabs in comparison with gas chromatography/electron capture detection-ion trap mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A gas chromatograph/electron capture detector-ion trap mass spectrometer (GC/ECD-ITMS) was used for the determination of polybrominated diphenyl ethers (PBDEs) in freshwater fish and crabs. The samples were also analyzed with an enzyme-linked immunosorbent assay (ELISA). GC/ECD-ITMS results showed...

  20. Application of DNA barcoding for identification of freshwater carnivorous fish diets: Is number of prey items dependent on size class for Micropterus salmoides?

    PubMed

    Jo, Hyunbin; Gim, Jeong-An; Jeong, Kwang-Seuk; Kim, Heui-Soo; Joo, Gea-Jae

    2014-01-01

    Understanding predator-prey interactions is a major challenge in ecological studies. In particular, the accurate identification of prey is a fundamental requirement in elucidating food-web structure. This study took a molecular approach in determining the species identity of consumed prey items of a freshwater carnivorous fish (largemouth bass, Micropterus salmoides), according to their size class. Thirty randomly selected gut samples were categorized into three size classes, based on the total length of the bass. Using the universal primer for the mtDNA cytochrome oxidase I (COI) region, polymerase chain reaction (PCR) amplification was performed on unidentified gut contents and then sequenced after cloning. Two gut samples were completely empty, and DNA materials from 27 of 28 gut samples were successfully amplified by PCR (success rate: 96.4%). Sequence database navigation yielded a total of 308 clones, containing DNA from 26 prey items. They comprised four phyla, including seven classes, 12 orders, and 12 families based on BLAST and BOLD database searches. The results indicate that largemouth bass show selective preferences in prey item consumption as they mature. These results corroborate a hypothesis, presence of ontogenetic diet shift, derived through other methodological approaches. Despite the practical limitations inherent in DNA barcoding analysis, high-resolution (i.e., species level) identification was possible, and the predation patterns of predators of different sizes were identifiable. The utilization of this method is strongly recommended for determining specific predator-prey relationships in complex freshwater ecosystems. PMID:24558577

  1. Application of DNA barcoding for identification of freshwater carnivorous fish diets: Is number of prey items dependent on size class for Micropterus salmoides?

    PubMed Central

    Jo, Hyunbin; Gim, Jeong-An; Jeong, Kwang-Seuk; Kim, Heui-Soo; Joo, Gea-Jae

    2014-01-01

    Understanding predator–prey interactions is a major challenge in ecological studies. In particular, the accurate identification of prey is a fundamental requirement in elucidating food-web structure. This study took a molecular approach in determining the species identity of consumed prey items of a freshwater carnivorous fish (largemouth bass, Micropterus salmoides), according to their size class. Thirty randomly selected gut samples were categorized into three size classes, based on the total length of the bass. Using the universal primer for the mtDNA cytochrome oxidase I (COI) region, polymerase chain reaction (PCR) amplification was performed on unidentified gut contents and then sequenced after cloning. Two gut samples were completely empty, and DNA materials from 27 of 28 gut samples were successfully amplified by PCR (success rate: 96.4%). Sequence database navigation yielded a total of 308 clones, containing DNA from 26 prey items. They comprised four phyla, including seven classes, 12 orders, and 12 families based on BLAST and BOLD database searches. The results indicate that largemouth bass show selective preferences in prey item consumption as they mature. These results corroborate a hypothesis, presence of ontogenetic diet shift, derived through other methodological approaches. Despite the practical limitations inherent in DNA barcoding analysis, high-resolution (i.e., species level) identification was possible, and the predation patterns of predators of different sizes were identifiable. The utilization of this method is strongly recommended for determining specific predator–prey relationships in complex freshwater ecosystems. PMID:24558577

  2. On two new species of the genus Cornudescoides Kulkarni, 1969 (Monogenea: Ancyrocephalinae) from a freshwater fish Mystus vittatus from Meerut (U.P.), India.

    PubMed

    Rastogi, Pragati; Mishra, Deepmala; Singh, Jyoti; Rani, Kavita

    2012-04-01

    During study of freshwater monogeneans of Meerut region, we came across five infected specimen of fish Mystus vittatus, infected with monogeneans belonging to the genus Cornudescoides Kulkarni 1969. On subsequent study, the worms appear new to us and are described here in as such. C. kulkarnii n. sp. is characterized by four pairs of head organs, nut cracker shaped accessory piece of cirrus, capitulum or patches with proximal conical protruberance, longer inner root of dorsal anchor and difference in shape and extension of dorsal bars. While C. susanii n. sp. is characterized by presence of seven pairs of head organs, caliper like accessory piece of cirrus, longer and inwardly curved lateral hooks, prominently protruded outer roots and larger inner roots of dorsal anchor. PMID:23543628

  3. Testing for shared biogeographic history in the lower Central American freshwater fish assemblage using comparative phylogeography: concerted, independent, or multiple evolutionary responses?

    PubMed Central

    Bagley, Justin C; Johnson, Jerald B

    2014-01-01

    A central goal of comparative phylogeography is determining whether codistributed species experienced (1) concerted evolutionary responses to past geological and climatic events, indicated by congruent spatial and temporal patterns (“concerted-response hypothesis”); (2) independent responses, indicated by spatial incongruence (“independent-response hypothesis”); or (3) multiple responses (“multiple-response hypothesis”), indicated by spatial congruence but temporal incongruence (“pseudocongruence”) or spatial and temporal incongruence (“pseudoincongruence”). We tested these competing hypotheses using DNA sequence data from three livebearing fish species codistributed in the Nicaraguan depression of Central America (Alfaro cultratus, Poecilia gillii, and Xenophallus umbratilis) that we predicted might display congruent responses due to co-occurrence in identical freshwater drainages. Spatial analyses recovered different subdivisions of genetic structure for each species, despite shared finer-scale breaks in northwestern Costa Rica (also supported by phylogenetic results). Isolation-with-migration models estimated incongruent timelines of among-region divergences, with A. cultratus and Xenophallus populations diverging over Miocene–mid-Pleistocene while P. gillii populations diverged over mid-late Pleistocene. Approximate Bayesian computation also lent substantial support to multiple discrete divergences over a model of simultaneous divergence across shared spatial breaks (e.g., Bayes factor [B10] = 4.303 for Ψ [no. of divergences] > 1 vs. Ψ = 1). Thus, the data support phylogeographic pseudoincongruence consistent with the multiple-response hypothesis. Model comparisons also indicated incongruence in historical demography, for example, support for intraspecific late Pleistocene population growth was unique to P. gillii, despite evidence for finer-scale population expansions in the other taxa. Empirical tests for phylogeographic congruence

  4. Geographical origin of Amazonian freshwater fishes fingerprinted by ⁸⁷Sr/⁸⁶Sr ratios on fish otoliths and scales.

    PubMed

    Pouilly, Marc; Point, David; Sondag, Francis; Henry, Manuel; Santos, Roberto V

    2014-08-19

    Calcified structures such as otoliths and scales grow continuously throughout the lifetime of fishes. The geochemical variations present in these biogenic structures are particularly relevant for studying fish migration and origin. In order to investigate the potential of the (87)Sr/(86)Sr ratio as a precise biogeochemical tag in Amazonian fishes, we compared this ratio between the water and fish otoliths and scales of two commercial fish species, Hoplias malabaricus and Schizodon fasciatus, from three major drainage basins of the Amazon: the Madeira, Solimões, and Tapajós rivers, displaying contrasted (87)Sr/(86)Sr ratios. A comparison of the (87)Sr/(86)Sr ratios between the otoliths and scales of the same individuals revealed similar values and were very close to the Sr isotopic composition of the local river where they were captured. This indicates, first, the absence of Sr isotopic fractionation during biological uptake and incorporation into calcified structures and, second, that scales may represent an interesting nonlethal alternative for (87)Sr/(86)Sr ratio measurements in comparison to otoliths. Considering the wide range of (87)Sr/(86)Sr variations that exist across Amazonian rivers, we used variations of (87)Sr/(86)Sr to discriminate fish origin at the basin level, as well as at the sub-basin level between the river and savannah lakes of the Beni River (Madeira basin). PMID:24971992

  5. Effects of a Dam Reservoir on the Distribution of Heavy Metals in Two Chilean Native Freshwater Fish Species.

    PubMed

    Copaja, S V; Muñoz, G S; Nuñez, V R; Pérez, C; Vila, I; Véliz, D

    2016-07-01

    In order to determine the effect of a dam on metal concentrations in riverine fish species, we studied fish inhabiting the influent (Cachapoal River) and effluent (Rapel River) of the Rapel Reservoir in central Chile. Heavy metals were quantified in gills, liver and muscle of the catfish Trichomycterus areolatus and the silverside Basilichthys microlepidotus. Also, the bioaccumulation index (BAI) was estimated by considering heavy metal concentrations obtained from water and sediment. Results showed the presence of Al, Cu, Fe, Mn, Pb and Zn in the fish organs. The analysis showed high metal concentrations in catfish inhabiting the influent compared to those collected in the effluent. These results indicate a possible filter effect of the dam for most of the metals identified in the fish organs, because metal concentrations decreased in the effluent. Finally, catfish exhibited a larger BAI for most metals analyzed. PMID:27230028

  6. Comparison of the elemental composition of different hard parts (otoliths, scales, fin rays, vertebrae and eye lenses) of freshwater fish using ICPMS

    NASA Astrophysics Data System (ADS)

    Kirchmaier, Leo; Irrgeher, Johanna; Prohaska, Thomas; Zitek, Andreas

    2013-04-01

    Elemental and isotopic fingerprints of different hard parts of fish are a powerful tool to gain life history information of individual fish. Most of these structures, like otoliths, scales, fin rays and vertebrae show incremental growth, allowing for a time resolved analysis of this information using e.g. laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS). Scales and fin-rays serve as important non-lethal alternatives to otoliths. Additional structures without incremental growth such as eye lenses might contain complementary information. However, there is a lack of solid matrix-matched reference materials that are needed to quantify elemental concentrations using LA-ICPMS. In this study we determined the elemental composition ("elemental fingerprint") of otoliths, scales, fin rays, vertebrae and eye lenses from freshwater fish of the Danube catchment using microwave-assisted digestion and solution based inductively coupled plasma mass spectrometry in order to gain information on the natural concentration ranges of various elements of interest in such samples. The investigation has focused on macro (Ca, Mg and P), minor and trace elements (Ba, Cu, Mn, Pb, Sr and Zn). Method validation was performed using the following certified reference materials (CRMs): riverine water (NRC SLRS-5), bone ash (NIST SRM 1400), bone meal (NIST SRM 1486) and fish otolith (NRC FEBS-1). Significant differences in elemental concentrations among different hard parts analyzed were found suggesting that different structures might be suited for a particular research purpose e.g. tracing environmental pollution. Based on this work, the preparation of in-house certified matrix-matched reference materials (co-precipitated hydroxyapatite calibration standards pressed to pellets) is established allowing for the quantification of the elemental concentration on a time resolved level in different hard parts by direct solid sampling via laser.

  7. Fine-tuning for the tropics: application of eDNA technology for invasive fish detection in tropical freshwater ecosystems.

    PubMed

    Robson, Heather L A; Noble, Tansyn H; Saunders, Richard J; Robson, Simon K A; Burrows, Damien W; Jerry, Dean R

    2016-07-01

    Invasive species pose a major threat to aquatic ecosystems. Their impact can be particularly severe in tropical regions, like those in northern Australia, where >20 invasive fish species are recorded. In temperate regions, environmental DNA (eDNA) technology is gaining momentum as a tool to detect aquatic pests, but the technology's effectiveness has not been fully explored in tropical systems with their unique climatic challenges (i.e. high turbidity, temperatures and ultraviolet light). In this study, we modified conventional eDNA protocols for use in tropical environments using the invasive fish, Mozambique tilapia (Oreochromis mossambicus) as a detection model. We evaluated the effects of high water temperatures and fish density on the detection of tilapia eDNA, using filters with larger pores to facilitate filtration. Large-pore filters (20 μm) were effective in filtering turbid waters and retaining sufficient eDNA, whilst achieving filtration times of 2-3 min per 2-L sample. High water temperatures, often experienced in the tropics (23, 29, 35 °C), did not affect eDNA degradation rates, although high temperatures (35 °C) did significantly increase fish eDNA shedding rates. We established a minimum detection limit for tilapia (1 fish/0.4 megalitres/after 4 days) and found that low water flow (3.17 L/s) into ponds with high fish density (>16 fish/0.4 megalitres) did not affect eDNA detection. These results demonstrate that eDNA technology can be effectively used in tropical ecosystems to detect invasive fish species. PMID:26849294

  8. High variability in stable isotope diet-tissue discrimination factors of two omnivorous freshwater fishes in controlled ex situ conditions.

    PubMed

    Busst, Georgina M A; Britton, J Robert

    2016-04-01

    Diet-tissue discrimination factors (Δ(13)C and Δ(15)N) are influenced by variables including the tissues being analysed and the taxon of the consumer and its prey. Whilst differences in Δ(13)C and Δ(15)N are apparent between herbivorous and piscivorous fishes, there is less known for omnivorous fishes that consume plant and animal material. Here, the omnivorous cyprinid fishes Barbus barbus and Squalius cephalus were held in tank aquaria and exposed to three diets that varied in their constituents (plant based to fishmeal based) and protein content (13% to 45%). After 100 days and isotopic replacement in fish tissues to 98%, samples of the food items, and dorsal muscle, fin tissue and scales were analysed for δ(13)C and δ(15)N. For both species and all diets, muscle was always enriched in δ(15)N and depleted in δ(13)C compared with fin tissue and scales. Across the different diets, Δ(13)C ranged between 2.0‰ and 5.6‰ and Δ(15)N ranged between 2.0‰ and 6.9‰. The diet based on plant material (20% protein) always resulted in the highest discrimination factors for each tissue, whilst the diet based on fishmeal (45% protein) consistently resulted in the lowest. The discrimination factors produced by non-fish diets were comparatively high compared with values in the literature, but were consistent with general patterns for some herbivorous fishes. These outputs suggest that the diet-tissue discrimination factors of omnivorous fishes will vary considerably between animal and plant prey, and these specific differences need consideration in predictions of their diet composition and trophic position. PMID:26896544

  9. Cascading life-history interactions: alternative density-dependent pathways drive recruitment dynamics in a freshwater fish.

    PubMed

    Vandenbos, Rena E; Tonn, William M; Boss, Shelly M

    2006-07-01

    Although density-dependent mechanisms in early life-history are important regulators of recruitment in many taxa, consequences of such mechanisms on other life-history stages are poorly understood. To examine interacting and cascading effects of mechanisms acting on different life-history stages, we stocked experimental ponds with fathead minnow (Pimephales promelas) at two different densities. We quantified growth and survival of the stocked fish, the eggs they produced, and the resulting offspring during their first season of life. Per-capita production and survival of eggs were inversely related to density of stocked fish; significant egg cannibalism by stocked minnows resulted in initial young-of-the-year (YOY) densities that were inversely related to adult densities. Subsequent growth and survival of YOY were then inversely related to these initial YOY densities, and survival of YOY was selective for larger fish. Because of these compensatory processes in the egg and YOY stages, treatments did not differ in YOY abundance and mean size at the end of the growing season. Because of differences in the intensity of size-selective mortality, however, variation in end-of season sizes of YOY was strongly (and inversely) related to densities of stocked fish. When mortality was severe in the egg stage (high densities of stocked fish), final YOY size distributions were more variable than when the dominant mortality was size-selective in the YOY stage (low stocked fish densities). These differences in size variation could have subsequent recruitment consequences, as overwinter survival is typically selective for YOY fish larger than a critical threshold size. Density-dependent effects on a given life stage are not independent, but will be influenced by earlier stages; alternative recruitment pathways can result when processes at earlier stages differ in magnitude or selectivity. Appreciation of these cascading effects should enhance our overall understanding of the

  10. Effects of different cooking methods on fatty acid profiles in four freshwater fishes from the Laurentian Great Lakes region.

    PubMed

    Neff, Margaret R; Bhavsar, Satyendra P; Braekevelt, Eric; Arts, Michael T

    2014-12-01

    Fish is often promoted as a healthy part of the human diet due its high content of long chain n-3 polyunsaturated fatty acids (LC-PUFA). Previous studies have shown that cooked fish can have different fatty acid profiles than raw fillets, depending on the cooking method and fish species. In this study, the fatty acid content of broiled, baked or fried skinless, boneless fillets of four fish species from the tributaries of the Great Lakes, or connecting rivers, was compared to fatty acid profiles in raw sections from the same fillet. Cooking treatments had little effect on n-3 fatty acid content; however, fried treatments generally had higher n-6 and MUFA content, which is likely a result of the cooking oil used (canola). Broiling or baking is generally the most healthy option presented in this study, as these methods result in lower levels of less-favourable fatty acids; however, the choice of cooking oil may also influence the overall fatty acid content in cooked fish. PMID:24996368

  11. Pharmacodynamic interaction of Spirulina platensis and deltamethrin in freshwater fish Nile tilapia, Oreochromis niloticus: impact on lipid peroxidation and oxidative stress.

    PubMed

    Abdelkhalek, Nevien K M; Ghazy, Emad W; Abdel-Daim, Mohamed M

    2015-02-01

    Spirulina platensis (SP) is one of the most commonly used dietary supplements in human and many animal species, including fish. Recently, it has gained more attention in fish not only for its growth-promoting and immunomodulatory effects but also for its antioxidant potential. The present study was conducted to investigate the protective role of two different dietary levels of SP on freshwater Nile tilapia; Oreochromis niloticus exposed to subacute deltamethrin (DLM) intoxication. Spirulina was supplemented at levels of 0.5 and 1 % in the diet along with DLM at a concentration of 1.46 μg/l for 28 days. Serum biochemical parameters, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total protein, albumin, cholesterol, urea, uric acid and creatinine, were estimated. In addition, the level of malondialdehyde (MDA) was analysed as a lipid peroxidation marker. Reduced glutathione (GSH) content and glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) activities were analysed as antioxidant biomarkers in liver, kidney and gills. The results revealed that DLM intoxication increased serum AST, ALT, ALP, cholesterol, urea, uric acid, creatinine and tissue MDA, while decreased serum total protein and albumin as well as tissue GSH level and GSH-Px, SOD and CAT activities. SP supplementation at the two tested levels enhanced all altered serum biochemical parameters as well as tissue lipid peroxidation and antioxidant biomarkers. Therefore, it could be concluded that SP administration could minimize DLM-induced toxic effects by its free radical scavenging and potent antioxidant activity. PMID:25231739

  12. Evaluation of a method for determining concentrations of isoeugenol, an AQUI-S residue, in fillet tissue from freshwater fish species.

    USGS Publications Warehouse

    Meinertz, J.R.; Schreier, T.M.; Bernardy, J.A.

    2008-01-01

    AQUI-S is a fish anesthetic/sedative that is approved for use in a number of countries throughout the world and has the potential for use in the United States. The active ingredient in AQUI-S is isoeugenol. A method for determining isoeugenol concentrations in edible fillet tissue is needed for regulatory purposes, including surveillance and potential use in studies fulfilling human food safety data requirements if U.S. Food and Drug Administration approval is pursued. A method was developed and evaluated for determining isoeugenol concentrations in fillet tissue using relatively common procedures and equipment. The method produced accurate and precise results with fillet tissue from 10 freshwater fish species. The percentage of isoeugenol recovered from samples fortified with isoeugenol at nominal concentrations of 1, 50, and 100 microg/g for all species was always >80 and <97%. Within-day precision for samples fortified at those same concentrations was < or =10%, and day-to-day precision was < or =4.0%. Method precision with fillet tissue containing biologically incurred isoeugenol was < or =8.1%. There were no or minimal chromatographic interferences in control fillet tissue extracts from 9 of the 10 species. The method detection limits for all but one species ranged from 0.004 to 0.014 microg/g, and the quantitation limits ranged from 0.012 to 0.048 microg/g.

  13. TROPHIC STRUCTURE MODIFICATIONS BY PLANKTIVOROUS FISH IN AQUATIC MICROCOSMS

    EPA Science Inventory

    Two of 4 replicate 700-liter aquatic microcosms each were stocked with 2 mosquito fish (Gambusia affinis). The dominant zooplankter shifted from the large cladoceran Simocephalus vetulus to the smaller Alona guttata. The subsequent release of grazing pressure resulted in a rise i...

  14. Clear as mud: a meta-analysis on the effects of sedimentation on freshwater fish and the effectiveness of sediment-control measures.

    PubMed

    Chapman, Jacqueline M; Proulx, Catherine L; Veilleux, Maxime A N; Levert, Caroline; Bliss, Shireen; André, Marie-Ève; Lapointe, Nicolas W R; Cooke, Steven J

    2014-06-01

    Increase in fine sediments in freshwater resulting from anthropogenic development is a potential stressor for fish and thus may cause population declines. Though a large body of literature exists on the topic, there have been few attempts to synthesize this information in a quantitative manner. Through meta-analysis we investigated the effects of sediment in lotic environments on resident ichthyofauna using ecologically-relevant endpoints for tolerant (e.g., northern pike Esox lucius) and intolerant (e.g., brook trout Salvelinus fontinalis) species. Further, the efficiency of sediment-control devices was explored to inform mitigation measures. An increase in suspended and deposited sediments was demonstrated to have a negative effect on all parameters and tolerances tested (feeding behavior [feeding rate, reaction distance to food item]; spawning success [survival of fry to eyed stage, fry emergence]; species richness; P < 0.001) except fish abundance (P = 0.058). Heterogeneity between studies was a factor in all analyses. Although there were insufficient studies to conduct meta-analysis on sediment-control devices, weighted percent efficiency estimates revealed that properly installed sediment-control fences tended to have a higher percent efficiency (73-80%) than sediment traps and basins (40-52%). These results highlight the negative impact that increases in suspended and deposited sediments can have on resident fishes from the individual to the population, and the need for more transparent and thorough statistical reporting. The analysis also identifies a clear need for rigorous experimental studies contrasting different sediment-control devices and strategies given that little such work has been published. That alone is remarkable given that sediment-control devices are often a requirement of regulators for riparian development activities, yet the evidence to support the effectiveness of the primary mitigative strategies is weak. PMID:24681235

  15. Oil shale processing as a source of aquatic pollution: monitoring of the biologic effects in caged and feral freshwater fish.

    PubMed Central

    Tuvikene, A; Huuskonen, S; Koponen, K; Ritola, O; Mauer, U; Lindström-Seppä, P

    1999-01-01

    The biologic effects of the oil shale industry on caged rainbow trout (Oncorhynchus mykiss) as well as on feral perch (Perca fluviatilis) and roach (Rutilus rutilus) were studied in the River Narva in northeast Estonia. The River Narva passes the oil shale mining and processing area and thus receives elevated amounts of polycyclic aromatic hydrocarbons (PAHs), heavy metals, and sulfates. The effects of the chemical load were monitored by measuring cytochrome P4501A (CYP1A)-dependent monooxygenase (MO) activities [7-ethoxyresorufin O-deethylase and aryl hydrocarbon hydroxylase (AHH)] as well as conjugation enzyme activities [glutathione S-transferase (GST) and UDP-glucuronosyltransferase] in the liver of fish. CYP1A induction was further studied by detecting the amount and occurrence of the CYP1A protein. Histopathology of tissues (liver, kidney, spleen, and intestine) and the percentage of micronuclei in fish erythrocytes were also determined. Selected PAHs and heavy metals (Cd, Cu, Hg, and Pb) were measured from fish muscle and liver. In spite of the significant accumulation of PAHs, there was no induction of MO activities in any studied fish species. When compared to reference samples, AHH activities were even decreased in feral fish at some of the exposed sites. Detection of CYP1A protein content and the distribution of the CYP1A enzyme by immunohistochemistry also did not show extensive CYP1A induction. Instead, GST activities were significantly increased at exposed sites. Detection of histopathology did not reveal major changes in the morphology of tissues. The micronucleus test also did not show any evidence of genotoxicity. Thus, from the parameters studied, GST activity was most affected. The lack of catalytic CYP1A induction in spite of the heavy loading of PAHs was not studied but has been attributed to the elevated content of other compounds such as heavy metals, some of which can act as inhibitors for MOs. Another possible explanation of this lack of

  16. Environmental contaminants in freshwater fish and their risk to piscivorous wildlife based on a national monitoring program

    USGS Publications Warehouse

    Hinck, J.E.; Schmitt, C.J.; Chojnacki, K.A.; Tillitt, D.E.

    2009-01-01

    Organochlorine chemical residues and elemental concentrations were measured in piscivorous and benthivorous fish at 111 sites from large U.S. river basins. Potential contaminant sources such as urban and agricultural runoff, industrial discharges, mine drainage, and irrigation varied among the sampling sites. Our objectives were to provide summary statistics for chemical contaminants and to determine if contaminant concentrations in the fish were a risk to wildlife that forage at these sites. Concentrations of dieldrin, total DDT, total PCBs, toxaphene, TCDD-EQ, cadmium, chromium, mercury, lead, selenium, and zinc exceeded toxicity thresholds to protect fish and piscivorous wildlife in samples from at least one site; most exceedences were for total PCBs, mercury, and zinc. Chemical concentrations in fish from the Mississippi River Basin exceeded the greatest number of toxicity thresholds. Screening level wildlife risk analysis models were developed for bald eagle and mink using no adverse effect levels (NOAELs), which were derived from adult dietary exposure or tissue concentration studies and based primarily on reproductive endpoints. No effect hazard concentrations (NEHC) were calculated by comparing the NOAEL to the food ingestion rate (dietary-based NOAEL) or biomagnification factor (tissue-based NOAEL) of each receptor. Piscivorous wildlife may be at risk from a contaminant if the measured concentration in fish exceeds the NEHC. Concentrations of most organochlorine residues and elemental contaminants represented no to low risk to bald eagle and mink at most sites. The risk associated with pentachloroanisole, aldrin, Dacthal, methoxychlor, mirex, and toxaphene was unknown because NOAELs for these contaminants were not available for bald eagle or mink. Risk differed among modeled species and sites. Our screening level analysis indicates that the greatest risk to piscivorous wildlife was from total DDT, total PCBs, TCDD-EQ, mercury, and selenium. Bald eagles

  17. Environmental contaminants in freshwater fish and their risk to piscivorous wildlife based on a national monitoring program.

    PubMed

    Hinck, Jo Ellen; Schmitt, Christopher J; Chojnacki, Kimberly A; Tillitt, Donald E

    2009-05-01

    Organochlorine chemical residues and elemental concentrations were measured in piscivorous and benthivorous fish at 111 sites from large U.S. river basins. Potential contaminant sources such as urban and agricultural runoff, industrial discharges, mine drainage, and irrigation varied among the sampling sites. Our objectives were to provide summary statistics for chemical contaminants and to determine if contaminant concentrations in the fish were a risk to wildlife that forage at these sites. Concentrations of dieldrin, total DDT, total PCBs, toxaphene, TCDD-EQ, cadmium, chromium, mercury, lead, selenium, and zinc exceeded toxicity thresholds to protect fish and piscivorous wildlife in samples from at least one site; most exceedences were for total PCBs, mercury, and zinc. Chemical concentrations in fish from the Mississippi River Basin exceeded the greatest number of toxicity thresholds. Screening level wildlife risk analysis models were developed for bald eagle and mink using no adverse effect levels (NOAELs), which were derived from adult dietary exposure or tissue concentration studies and based primarily on reproductive endpoints. No effect hazard concentrations (NEHC) were calculated by comparing the NOAEL to the food ingestion rate (dietary-based NOAEL) or biomagnification factor (tissue-based NOAEL) of each receptor. Piscivorous wildlife may be at risk from a contaminant if the measured concentration in fish exceeds the NEHC. Concentrations of most organochlorine residues and elemental contaminants represented no to low risk to bald eagle and mink at most sites. The risk associated with pentachloroanisole, aldrin, Dacthal, methoxychlor, mirex, and toxaphene was unknown because NOAELs for these contaminants were not available for bald eagle or mink. Risk differed among modeled species and sites. Our screening level analysis indicates that the greatest risk to piscivorous wildlife was from total DDT, total PCBs, TCDD-EQ, mercury, and selenium. Bald eagles

  18. Two new species of Phyllodistomum Braun, 1899 (Digenea: Gorgoderidae), from freshwater fishes (Cyprinodontiformes: Goodeidae: Goodeinae) in central Mexico: An integrative taxonomy approach using morphology, ultrastructure and molecular phylogenetics.

    PubMed

    Pérez-Ponce de León, Gerardo; Martínez-Aquino, Andrés; Mendoza-Garfias, Berenit

    2015-01-01

    An integrative taxonomy approach is used to characterise the diversity of gorgoderid trematodes that parasitize freshwater fishes of the subfamily Goodeinae in central Mexico. Records of Phyllodistomum sp. and Dendrorchis sp. from the urinary bladder of goodeines have been previously published, although the identification at species level was not achieved. A few specimens were collected and fixed to conduct a scanning electron microscopy study, and to obtain sequences of a mitochondrial (COI) and nuclear (28S rRNA) gene, to be analysed in the context of the molecular phylogeny of gorgoderid trematodes. Based on the new findings, two new species of Phyllodistomum Braun, 1899 are described. Phyllodistomum cribbi n. sp. was found in Zoogoneticus quitzeoensis (Bean), Allotoca zacapuensis Meyer, Radda & Domínguez-Domínguez, Hubbsina turneri de Buen and Z. purhepechus Domínguez-Domínguez, Pérez-Rodríguez & Doadrio from Zacapu Lake, and La Luz Spring, in Michoacan, central Mexico. Phyllodistomum wallacei n. sp. parasitized Xenotaenia resolanae Turner, Ilyodon furcidens (Jordan & Gilbert), and Allodontichthys tamazulae Turner from the Cuzalapa, Ayuquila and Tamazula Rivers in Jalisco, western Mexico. These species are compared with several freshwater Phyllodistomum species from different areas of the world, especially a group of eight species that comprise a monophyletic clade in recent phylogenetic hypotheses of the Gorgoderidae Looss, 1899. The two new species are distinguished from other close relatives by the combination of morphological traits such as the body shape, sucker ratio, shape of the gonads, and extension of intestinal ceca. The new species are distinct in some ultrastructural characters of the body surface when compared with those species where scanning electron micrographs (SEM) and/or microphotographs are available. Data of two molecular markers (28S rRNA and COI genes) demonstrate that the two new species are distinct from each other and from those

  19. A comparative analysis on the in vivo toxicity of copper nanoparticles in three species of freshwater fish.

    PubMed

    Song, Lan; Vijver, Martina G; Peijnenburg, Willie J G M; Galloway, Tamara S; Tyler, Charles R

    2015-11-01

    Copper nanoparticles (CuNPs) are used extensively in a wide range of products and the potential for toxicological impacts in the aquatic environment is of high concern. In this study, the fate and the acute toxicity of spherical 50nm copper nanoparticles was assessed in juvenile rainbow trout (Oncorhynchus mykiss), fathead minnow (Pimephales promelas) and zebrafish (Danio rerio) for in vivo aqueous exposures following standardized OECD 203 guideline tests. The fate of the CuNPs in the aqueous media was temperature dependent. At the higher study temperature (26±1°C), there was both an enhanced particle aggregation and higher rate of dissolution compared with that at the lower study temperature (15±1°C). 96h LC50s of the CuNPs were 0.68±0.15, 0.28±0.04 and 0.22±0.08mg Cu/L for rainbow trout, fathead minnow and zebrafish, respectively. The 96h lowest-observed-effect concentration (LOEC) for the CuNPs were 0.17, 0.023 and <0.023mg/L for rainbow trout, fathead minnow, and zebrafish respectively, and are below the predicted environmental concentration of CuNPs for some aquatic environments suggesting a possible ecotoxicological risk to fish. Soluble copper was one of main drivers for the acute toxicity of the copper nanoparticles suspensions. Both CuNPs suspension and copper nitrate caused damage to gill filaments and gill pavement cells, with differences in sensitivity for these effects between the fish species studied. We show therefore common toxicological effects of CuNPs in different fish species but with differences in sensitivity with implications for hazard extrapolation between fish species. PMID:26121603

  20. Vitamins A{sub 1}, A{sub 2}, and E in minks exposed to polychlorinated biphenyls (Aroclor 1242{reg{underscore}sign}) and copper, via diet based on freshwater or marine fish

    SciTech Connect

    Kaekelae, R.; Kaekelae, A.; Hyvaerinen, H.; Asikainen, J.; Dahl, S.K.

    1999-11-01

    Minks (Mustela vison) fed diets based on either freshwater fish or marine fish were exposed to 1 mg of polychlorinated biphenyls (PCBs) (Aroclor 1242) daily for 28 d. To minks on the freshwater diet, copper was also given with or without PCBs. The marine diet included more vitamin A, and E than the freshwater diet. The authors studied how the exposures affected levels of vitamins A{sub 1}, A{sub 2}, and E in liver and adipose tissues and levels of vitamins A{sub 1} and A{sub 2} in plasma. In females and males on the freshwater diet, the hepatic level of vitamin A{sub 2} was decreased because of the PCBs, and in these males the hepatic levels of vitamin E also decreased. Interestingly, with coexposure to PCBs and copper, the vitamin levels were, in general, close to the control values. In adipose tissues also, the PCBs induced significant changes in the concentrations of vitamins A{sub 1} and A{sub 2}. In plasma, vitamins A{sub 1} and A{sub 2} were decreased in all patterns of exposure and on both diets. However, plasma thyroxine was slightly increased, a finding opposite to that reported previously in rodent studies. The results suggest that, in mink, diet greatly modulates the responses to PCBs, which may also differ in males and females. Furthermore, vitamins A{sub 1} and A{sub 2} may not be metabolized equally during PCB administration.

  1. Geographic variation within a tandemly repeated mitochondrial DNA D-loop region of a North American freshwater fish, Pylodictis olivaris.

    PubMed

    Padhi, Abinash

    2014-03-15

    The present study reports the distribution of a 35-bp mitochondrial DNA (mtDNA) D-loop tandemly repeated sequence in the populations of a North American freshwater catfish, Pylodictis olivaris, and the important role of a past geological event in the phylogeographic pattern of this species. A total of 330 individuals of flathead catfish, representing 34 drainages throughout the species' native range in the United States, were collected. While more than 70% of individuals sampled from the Southeastern Gulf Coast drainages were characterized by the presence of a 35-bp mtDNA D-loop tandem repeat proximal to the 5' end, more than 95% of samples from the Mississippi River and its tributaries, as well as from the drainages of the Southwest Gulf Coast region, lack this tandem repeat. Concomitantly, phylogenetic analyses revealed the existence of two distinct matrilineal lineages (lineage I and II) of P. olivaris, which were estimated to have diverged from a common ancestor sometime between 0.70 and 2.05myr ago. While one lineage is comprised of samples from the Mississippi River and its tributaries and rivers draining to the Southwest Gulf Coast, the other lineage is comprised of samples from the Southeastern Gulf Coast drainages. Each lineage also has two sub-lineages, which also showed geographic specificity. PMID:24440244

  2. Record of Urocleidoides vaginoclaustrum Jogunoori, Kritsky and Venkatanarasaiah, 2004 (Monogenea: Dactylogyridae) from a freshwater fish in Mexico.

    PubMed

    Mendoza-Palmero, C A; Aguilar-Aguilar, R

    2008-10-01

    We describe herein the first occurrence of the monogenean Urocleidoides vaginoclaustrum in the wild. This monogenean was originally described from an aquarium neotropical fish examined in India. Worms were collected from the gills of Xiphophorus hellerii, a species native to tropical Mexico but introduced to the Los Berros Spring in the State of Durango, Northern Mexico. These specimens showed slight morphological differences in the sclerotized structures of the haptor with respect to the specimens described from India. A brief morphological characterization of this species is presented. PMID:18661283

  3. Freshwater Macroinvertebrates.

    ERIC Educational Resources Information Center

    Nalepa, T. F.

    1978-01-01

    Presents a literature review of freshwater biology particularly freshwater macroinvertebrates and their effect on water pollution, covering publications of 1976-77. A list of 158 references is also presented. (HM)

  4. Isolation and characterization of potential lactic acid bacteria (LAB) from freshwater fish processing wastes for application in fermentative utilisation of fish processing waste.

    PubMed

    R, Jini; Hc, Swapna; Rai, Amit Kumar; R, Vrinda; Pm, Halami; Nm, Sachindra; N, Bhaskar

    2011-10-01

    Proteolytic and/or lipolytic lactic acid bacteria (LAB) were isolated from visceral wastes of different fresh water fishes. LAB count was found to be highest in case of visceral wastes of Mrigal (5.88 log cfu/g) and lowest in that of tilapia (4.22 log cfu/g). Morphological, biochemical and molecular characterization of the selected LAB isolates were carried out. Two isolates FJ1 (E. faecalis NCIM5367) and LP3 (P. acidilactici NCIM5368) showed both proteolytic and lipolytic properties. All the six native isolates selected for characterization showed antagonistic properties against several human pathogens. All the native isolates were sensitive to antibiotics cephalothin and clindamycin; and, resistant to cotrimoxazole and vancomycin. Considering individually, P. acidilactici FM37, P. acidilactici MW2 and E. faecalis FD3 were sensitive to erythromycin. The two strains FJ1 (E. faecalis NCIM 5367) and LP3 (P. acidilactici NCIM 5368) that had both proteolytic and lipolytic properties have the potential for application in fermentative recovery of lipids and proteins from fish processing wastes. PMID:24031786

  5. Population substructuring in a migratory freshwater fish Prochilodus argenteus (Characiformes, Prochilodontidae) from the São Francisco River.

    PubMed

    Hatanaka, Terumi; Henrique-Silva, Flávio; Galetti, Pedro Manoel

    2006-01-01

    The construction of hydroelectric dams, pollution of rivers and other environmental changes are responsible for the disappearance of many natural fish stocks. The purpose of this work was to analyze the fish Prochilodus argenteus inhabiting the region of the Três Marias dam in the São Francisco River (Brazil) collected in two sites having distinct environmental characteristics. Three novel homologous and one known cross-specific microsatellites were used to assess genetic variation within and between the two collection sites (namely A and B) in order to confirm the occurrence of population substructuring previously suggested using RAPD markers. A higher number of exclusive alleles and a greater genetic variability in region B strongly reinforce the co-existence of different reproductive units in this area. F(ST) estimates showed a significant population differentiation between the two sites, indicating the possible existence of distinct gene pools. Considering the economic importance of this fishery resource in the São Francisco River, these findings could provide very important information for fisheries management, aquaculture and conservation of the stocks of this species. PMID:16502092

  6. Evaluation of a recirculating pond system for rearing juvenile freshwater mussels at White Sulphur Springs National Fish Hatchery, West Virginia, U.S.A.

    USGS Publications Warehouse

    Mummert, A.; Newcomb, T.J.; Neves, R.J.; Parker, B.

    2006-01-01

    A recirculating double-pond system at White Sulphur Springs National Fish Hatchery in West Virginia, U.S.A., was evaluated for suitability for culturing juvenile freshwater mussels. Newly metamorphosed juveniles of Villosa iris and Lampsilis fasciola were placed in the system, and their growth and survival were evaluated for 94 days. Throughout the study, parameters of water quality remained within ranges suitable for mussel survival. Planktonic algal densities in the pond system ranged from 2850 to 6892 cells/ml. Thirty-seven algal taxa were identified, primarily green algae (Chlorophyta), diatoms (Bacillariophyceae), and blue-green algae (Cyanoprokaryota). Over the culture period, juveniles of L. fasciola experienced significantly lower (p < 0.001) survival (6.3% ?? 4.5) than those of V. iris (49.8% ?? 14.5). The very low survival rate of L. fasciola may indicate a failure of the flow-through pond environment to meet its habitat requirements or that variable microhabitat conditions within culture containers existed. Growth did not differ significantly between the species (p = 0.13). Survival of V. iris and growth of both species were similar to previous trials to culture juvenile mussels. Survival rates as high as 66.4% at 93 days for V. iris suggest that juveniles of some riverine species can be successfully cultured in a recirculating pond environment.

  7. Detection, partial purification and characterization of bacteriocin produced by Lactobacillus brevis FPTLB3 isolated from freshwater fish: Bacteriocin from Lb. brevis FPTLB3.

    PubMed

    Banerjee, Shiba Prosad; Dora, Krushna Chandra; Chowdhury, Supratim

    2013-02-01

    Lactobacillus brevis FPTLB3 was isolated from freshwater fish, capable of producing bacteriocin that had broad spectrum of inhibition (3200 AU/ml) against Escherichia coli MTCC 1563, Enterococcus faecalis MTCC 2729, Lactobacillus casei MTCC 1423, Lactobacillus sakei ATCC 15521 and Staphylococcus aureus ATCC 25923. The antimicrobial activity of crude supernatant fluid was stable after heating at 121 °C for 60 min and declined thereafter. Stability of antimicrobial activity was observed at pH range of 2.0 to 8.0. Its active principle was proteinaceous in nature since the bacteriocin was inactivated by proteolytic enzymes, but not by other non-proteolytic enzymes. Mitomycin C and UV light did not affect the activity of the bacteriocin, while chloroform extraction completely destroyed their activity. Exposure to surfactant resulted in an increase in titre, except Nonidet P-40, which led to total loss of activity. No bacteriocin adsorption was detected at pH 1 to 2, whereas 100% bacteriocin adsorption was found at pH 6.5. Based on Tricine SDS-PAGE the estimated molecular mass of bacteriocin was 54 kDa. No plasmid was found to present in the isolate. PMID:24425883

  8. Potaspora aequidens n. sp. (Microsporidia, Tetramicridae), a parasite infecting the freshwater fish Aequidens plagiozonatus (Teleostei, Cichlidae) from Brazil.

    PubMed

    Videira, Marcela; Casal, Graça; Rocha, Sónia; Gonçalves, Evonnildo; Azevedo, Carlos; Velasco, Michele; Matos, Edilson Rodrigues

    2015-07-01

    Morphological and molecular procedures were used to describe a new species of microsporidian that infects the muscles of the sub-opercular region and the caudal fins of the freshwater Aequidens plagiozonatus in Brazil. This microsporidian forms whitish xenomas containing variable number of spores, reaching up to ~0.4 mm in diameter. The mature spores, pyriformin shape, with slightly round ends, measured 3.4 ± 0.5 μm long and 1.9 ± 0.3 μm wide (n = 50) and showed characteristics typical of Microsporidia. The average thickness of the spore wall was 100 (96-108) nm (n = 50), and the spore wall was composed of two layers, a thin, electron-dense exospore and a thick electron-transparent endospore. The exospore was surrounded by a thin, irregular layer of granular material. The anchoring disc was mushroom-like, located in the apical region of the spore in an eccentric position relative to the spore axis, rendering bilateral asymmetry to the spore. The anterior part of the polar filament (PF) (manubrium) measured approximately 125 (122-128) nm thick (n = 30), and the angle of tilt between the anterior PF and the spore axis was ~45°; the posterior part was packed in 8-9 coils. Phylogenetic analysis showed a strongly supported clade containing family Spragueidae Weissenberg, 1976, family Tetramicridae Matthews and Matthews, 1980, Microsporidium sp. RBS1, and Kabatana spp. In conclusion, the available morphological, ultrastructural, and molecular data shows that this microsporidian is a new species belonging to group 4, classified as Potaspora aequidens n. sp. This is the second species described in the genus Potaspora. PMID:25813455

  9. Phylogeny and biogeography of highly diverged freshwater fish species (Leuciscinae, Cyprinidae, Teleostei) inferred from mitochondrial genome analysis.

    PubMed

    Imoto, Junichi M; Saitoh, Kenji; Sasaki, Takeshi; Yonezawa, Takahiro; Adachi, Jun; Kartavtsev, Yuri P; Miya, Masaki; Nishida, Mutsumi; Hanzawa, Naoto

    2013-02-10

    The distribution of freshwater taxa is a good biogeographic model to study pattern and process of vicariance and dispersal. The subfamily Leuciscinae (Cyprinidae, Teleostei) consists of many species distributed widely in Eurasia and North America. Leuciscinae have been divided into two phyletic groups, leuciscin and phoxinin. The phylogenetic relationships between major clades within the subfamily are poorly understood, largely because of the overwhelming diversity of the group. The origin of the Far Eastern phoxinin is an interesting question regarding the evolutionary history of Leuciscinae. Here we present phylogenetic analysis of 31 species of Leuciscinae and outgroups based on complete mitochondrial genome sequences to clarify the phylogenetic relationships and to infer the evolutionary history of the subfamily. Phylogenetic analysis suggests that the Far Eastern phoxinin species comprised the monophyletic clades Tribolodon, Pseudaspius, Oreoleuciscus and Far Eastern Phoxinus. The Far Eastern phoxinin clade was independent of other Leuciscinae lineages and was closer to North American phoxinins than European leuciscins. All of our analysis also suggested that leuciscins and phoxinins each constituted monophyletic groups. Divergence time estimation suggested that Leuciscinae species diverged from outgroups such as Tincinae to be 83.3 million years ago (Mya) in the Late Cretaceous and leuciscin and phoxinin shared a common ancestor 70.7 Mya. Radiation of Leuciscinae lineages occurred during the Late Cretaceous to Paleocene. This period also witnessed the radiation of tetrapods. Reconstruction of ancestral areas indicates Leuciscinae species originated within Europe. Leuciscin species evolved in Europe and the ancestor of phoxinin was distributed in North America. The Far Eastern phoxinins would have dispersed from North America to Far East across the Beringia land bridge. The present study suggests important roles for the continental rearrangements during the

  10. A new fish cell line derived from the caudal fin of freshwater angelfish Pterophyllum scalare: development and characterization.

    PubMed

    Swaminathan, T R; Kumar, Raj; Jency, P M E; Charan, R; Syamkrishnan, M U; Basheer, V S; Sood, N; Jena, J K

    2016-09-01

    In this study, a new cell line derived from the caudal fin of the freshwater angelfish Pterophyllum scalare was developed and characterized. The cell line was designated angelfish fin (AFF) and subcultured 44 times since its development. These cells grew well in Leibovitz's -15 medium supplemented with 10% foetal bovine saline (FBS) at 28° C and the modal chromosome number (2n) was 48. The AFF cell-line is mainly comprised of epithelial cells as confirmed by immunocytological technique using anti-cytokeratin antibodies, an epithelial cell marker. This cell line was tested for growth in a temperatures range from 20 to 37° C and at various FBS concentrations of 5-20% at 28° C. The cell line was cryopreserved at different passage levels and revived successfully with 80% survival rate. Polymerase chain reaction amplification and sequencing of partial mitochondrial 16s rRNA and coI genes confirmed that the AFF cell-line originated from angelfish. Mycoplasma sp. contamination was not detected in AFF cells and checked by Hoechst 33258 fluorescence staining. At the 42nd passage the cells were transfected with 2 μg of pAcGFP1-N1 expression vector. The AFF cells exhibited cytotoxic effects when exposed to the bacterial extra cellular products from Serratia marcescens and Proteus hauseri. The AFF cells and cells from kidney and brain did not show cytopathic effect when exposed to cyprinid herpes virus2 and viral nervous necrosis virus. The newly developed AFF cell line will be useful for the isolation of viruses affecting angelfishes, such as iridoviruses, in the future. PMID:27458084

  11. Life history pattern of mosquitofish Gambusia holbrooki (Girard, 1859) in the Tajan River (Southern Caspian Sea to Iran)

    NASA Astrophysics Data System (ADS)

    Patimar, Rahman; Ghorbani, Mohsen; Gol-Mohammadi, Ali; Azimi-Glugahi, Hoda

    2011-01-01

    Investigation of the ecology of introduced species in new habitats can allow determinations of the degree, direction, and rate of evolutionary change. The introduction of Gambusia holbrooki in the southern Caspian Sea presents such a situation. We evaluated the life history traits of mosquitofish in the Tajan River basin. A total of 744 G. holbrooki specimens were collected between January and December 2008. The maximum observed ages are 0+ years for males and 1+ years for females. Both sexes grew allometrically (negative for males: b=2.442 and positive for females: b=3.232). The overall sex ratio is unbalanced and dominated by females. GSI values suggest that this population of G. holbrooki matures between February-July. The highest mean GSI value is 1.80 for males and 15.97 for females in May. Egg diameter ranges from 1.00 to 3.00 mm with a mean value of 2.098 mm. Absolute fecundity varied from 7 to 57 eggs. Both ova diameter and absolute fecundity were positively correlated to fish size (length and weight). Fecundity relative to total weight fluctuated from 34.44 to 582.64 eggs/g, and to total length from 2.33 to 12.95 eggs/cm. Both were negatively correlated with female size. The characteristics of this population are important with respect to life history of the species.

  12. Experimental Study on the Diet of Mosquitofish (Gambusia holbrooki) under Different Ecological Conditions in a Shallow Lake

    NASA Astrophysics Data System (ADS)

    Blanco, Saúl; Romo, Susana; Villena, María-José

    2004-07-01

    We studied the diet of the eastern mosquitofish Gambusia holbrooki with in situ experimental mesocosms located in a shallow lake. Different nutrient concentrations (phosphorus and nitrogen) and fish population densities were tested. Our results confirm that it is a planktivorous species, with also a great ingestion of algae and detritus. Nutrient fertilization caused almost no changes in this species feeding behavior, but larger mosquitofish stocks induced a shift to zooplanktivory and a decline in detritivory. When macrophytes were present, the predation effect focused on zooplankton and plant-associated animals, otherwise predation on bottom macroinvertebrates increased. Females preyed upon almost all groups more intensely, including detritus. Males and juveniles did not overlap diet, the former being more selective on ostracods, while juveniles consumed detritus, rotifers and cladoceran. Our data support the idea that mosquitofish can cause important top-down effects in shallow lakes under a wide variety of ecological conditions, being an important zooplanktivore in both turbid and plant-dominated shallow lakes especially in the Mediterranean zone, where high temperatures and absence of piscivores promote maintenance of its populations during the whole year. (

  13. Discovering the African freshwater "torpedo": legendary Ethiopia, religious controversies, and a catfish capable of reanimating dead fish.

    PubMed

    Piccolino, Marco; Finger, Stanley; Barbara, Jean-Gaël

    2011-07-01

    The electric catfishes of African rivers and lakes, once depicted on Egyptian tomb art, have been largely overlooked in histories and reviews of electric fish biology and animal electricity. This article examines how Westerners, especially Dominican and Jesuit missionaries, discovered them in Ethiopia and other parts of Africa at the beginning of the seventeenth century. What transpired took place against the backdrop of tales involving the Bible, Prester John's mythical empire, and imaginary animals with fabulous powers. In effect, how they were found is related to attempts to convert Ethiopian Christians to true Catholicism, hopes of discovering great riches, and opportunities to trade, and not with the efforts of skilled natural philosophers to document and conduct experiments on the wildlife of this continent. Nevertheless, the early descriptions by Europeans circulated, and during the next century these catfishes began to be used in experiments that helped to make animal electricity a reality. PMID:21736441

  14. The morphology and systematics of Rhabdochona paski Baylis, 1928 (Nematoda: Rhabdochonidae), a widespread parasite of freshwater fishes in Africa.

    PubMed

    Moravec, František; Charo-Karisa, Harrison; Jirků, Miloslav

    2013-05-01

    Nematodes of the genus Rhabdochona Railliet, 1916, identified as R. paski Baylis, 1928, were collected from the intestine of Hydrocynus forskahlii (Cuvier) (Characiformes: Alestidae), Oreochromis niloticus (Linnaeus) and Tilapia zillii (Gervais) (both Perciformes: Cichlidae) from Lake Turkana, Kenya during 2007-2009. Their morphology was studied in detail using light and scanning electron microscopy. Paratypes of R. paski and museum specimens of R. congolensis Campana-Rouget, 1961 from six other host species were examined for comparison. Based on these studies and the available literature data, Rhabdochona congolensis, R. aegyptiaca El-Nafar & Saoud, 1974 (emend.) and R. vesterae Boomker & Petter, 1993 are considered to be junior synonyms of R. paski. The occurrence of this widely distributed African nematode in many fish species belonging to different families and orders suggests that most of them are probably not definitive hosts of this parasite, but only serve as paratenic, paradefinitive or postcyclic hosts (sensu Odening, 1976). True definitive hosts of R. paski appear to be characiform species belonging to some genera (e.g., Alestes, Brycinus, Hydrocynus) of the family Alestidae. PMID:23595492

  15. From richer to poorer: successful invasion by freshwater fishes depends on species richness of donor and recipient basins.

    PubMed

    Fitzgerald, Daniel B; Tobler, Michael; Winemiller, Kirk O

    2016-07-01

    Evidence for the theory of biotic resistance is equivocal, with experiments often finding a negative relationship between invasion success and native species richness, and large-scale comparative studies finding a positive relationship. Biotic resistance derives from local species interactions, yet global and regional studies often analyze data at coarse spatial grains. In addition, differences in competitive environments across regions may confound tests of biotic resistance based solely on native species richness of the invaded community. Using global and regional data sets for fishes in river and stream reaches, we ask two questions: (1) does a negative relationship exist between native and non-native species richness and (2) do non-native species originate from higher diversity systems. A negative relationship between native and non-native species richness in local assemblages was found at the global scale, while regional patterns revealed the opposite trend. At both spatial scales, however, nearly all non-native species originated from river basins with higher native species richness than the basin of the invaded community. Together, these findings imply that coevolved ecological interactions in species-rich systems inhibit establishment of generalist non-native species from less diverse communities. Consideration of both the ecological and evolutionary aspects of community assembly is critical to understanding invasion patterns. Distinct evolutionary histories in different regions strongly influence invasion of intact communities that are relatively unimpacted by human actions, and may explain the conflicting relationship between native and non-native species richness found at different spatial scales. PMID:26582547

  16. Fine structure of the skin cells of a stenohaline freshwater fish Cyprinus carpio exposed to diluted seawater.

    PubMed

    Abraham, M; Iger, Y; Zhang, L

    2001-02-01

    Seawater diluted to half (1.750% salinity) is lethal for adult carps after 3 h and 15 min. At lower salinities (0.350%-0.875%), the fish survived for longer periods, but only 0.175% salinity was innocuous. In carps, adapted to 0.175% salinity, the secretory activity of pavement cells was very high and their external ridges flattened or even disappeared. Mucus secretion was conspicuous, characterized by holocriny of old cells and apparition of young ones in large numbers. The intracellular mucus droplets often coalesced. Pavement cells and mucus cells were disconnected from their neighboring tissue fabric and were sloughing off. Mitotic figures of filament cells were frequent, suggesting high turnover. Club cells appeared near the epidermal surface. The number of pinocytotic vesicles of the basal cell layer markedly decreased, indicating a possible decrease in dermis-epidermis molecular transfers. Leucocytes, mainly lymphocytes penetrated into the epidermis, where also rodlet cells appeared. The low salinity tolerance of the carp might be related among other possible factors to the absence of chloride cells in the skin. PMID:11292170

  17. Exposure to an agricultural contaminant, 17β-trenbolone, impairs female mate choice in a freshwater fish.

    PubMed

    Tomkins, Patrick; Saaristo, Minna; Allinson, Mayumi; Wong, Bob B M

    2016-01-01

    Despite the pivotal role sexual selection plays in population dynamics and broader evolutionary processes, the impact of chemical pollution on female mate choice is poorly understood. One group of chemical contaminants with the potential to disrupt the mechanisms of female mate choice is endocrine disrupting chemicals (EDCs); a broad class of environmental pollutants that can interfere with the endocrinology of organisms at extremely low concentrations. Recent research has revealed that estrogenic EDCs can affect female mate choice in fish, but the impact of androgenic EDC exposure is yet to be studied. To address this, we investigated the effects of an environmentally relevant concentration of trenbolone - an androgenic steroid used as a growth promoter in the cattle industry - on female mate choice in wild-caught guppies (Poecilia reticulata). We exposed male and female guppies to 17β-trenbolone for 21 days (measured concentration 4ng/L) via a flow-through system, and found that trenbolone-exposed female guppies spent less time associating with males, and were less choosy, compared to unexposed females. In contrast, trenbolone had no impact on male reproductive behavior or morphology. This is the first study to show that androgenic EDC exposure can disrupt female mate choice, highlighting the need for studies to investigate the behavioral impacts of environmental contaminants on both sexes. PMID:26466515

  18. Diversity, specificity and speciation in larval Diplostomidae (Platyhelminthes: Digenea) in the eyes of freshwater fish, as revealed by DNA barcodes.

    PubMed

    Locke, Sean A; Al-Nasiri, Fatima S; Caffara, Monica; Drago, Fabiana; Kalbe, Martin; Lapierre, Angela Rose; McLaughlin, J Daniel; Nie, Pin; Overstreet, Robin M; Souza, Geza T R; Takemoto, Ricardo M; Marcogliese, David J

    2015-11-01

    Larvae (metacercariae) in some species of Diplostomidae (Platyhelminthes: Digenea) inhabit fish eyes and are difficult to identify to species based on morphology. DNA barcoding has clarified the diversity and life cycles of diplostomids in North America, Europe and Africa, but has seldom been used in parasites sampled in large numbers or at large spatial scales. Here, distance-based analysis of cytochrome c oxidase 1 barcodes and, in some specimens, internal transcribed spacer (ITS-1, 5.8S, ITS-2) sequences was performed for over 2000 diplostomids from Africa, the Middle East, Europe, Asia and the Americas. Fifty-two species of Diplostomum, Tylodelphys and Austrodiplostomum (Digenea: Diplostomidae) were distinguished. The 52 species comprise 12 identified species, six species in two species complexes and 34 putative species, and 33/52 had been delineated in previous studies. Most (23/40) of the unidentified, putative species distinguished by cytochrome c oxidase 1 distances were supported by at least one additional line of evidence. As the intensity of sampling of the 52 species increased, variation in cytochrome c oxidase 1 decreased between and increased within species, while the spatial scale at which species were sampled had no effect. Nonetheless, variation between species always exceeded variation within species. New life-cycle linkages, geographic and host records, and genetic data were recorded in several species, including Tylodelphys jenynsiae, Tylodelphys immer and Diplostomum ardeae. Species of Diplostomum inhabiting the lens are less host-specific and less numerous than those infecting other tissues, suggesting that reduced immune activity in the lens has influenced rates of speciation. PMID:26276524

  19. Behavioural and physical effects of arsenic exposure in fish are aggravated by aquatic algae.

    PubMed

    Magellan, Kit; Barral-Fraga, Laura; Rovira, Marona; Srean, Pao; Urrea, Gemma; García-Berthou, Emili; Guasch, Helena

    2014-11-01

    Arsenic contamination has global impacts and freshwaters are major arsenic repositories. Arsenic toxicity depends on numerous interacting factors which makes effects difficult to estimate. The use of aquatic algae is often advocated for bioremediation of arsenic contaminated waters as they absorb arsenate and transform it into arsenite and methylated chemical species. Fish are another key constituent of aquatic ecosystems. Contamination in natural systems is often too low to cause mortality but sufficient to interfere with normal functioning. Alteration of complex, naturally occurring fish behaviours such as foraging and aggression are ecologically relevant indicators of toxicity and ideal for assessing sublethal impacts. We examined the effects of arsenic exposure in the invasive mosquitofish, Gambusia holbrooki, in a laboratory experiment incorporating some of the complexity of natural systems by including the interacting effects of aquatic algae. Our aims were to quantify the effects of arsenic on some complex behaviours and physical parameters in mosquitofish, and to assess whether the detoxifying mechanisms of algae would ameliorate any effects of arsenic exposure. Aggression increased significantly with arsenic whereas operculum movement decreased non-significantly and neither food capture efficiency nor consumption were notably affected. Bioaccumulation increased with arsenic and unexpectedly so did fish biomass. Possibly increased aggression facilitated food resource defence allowing fish to gain weight. The presence of algae aggravated the effects of arsenic exposure. For increase in fish biomass, algae acted antagonistically with arsenic, resulting in a disadvantageous reduction in weight gained. For bioaccumulation the effects were even more severe, as algae operated additively with arsenic to increase arsenic uptake and/or assimilation. Aggression was also highest in the presence of both algae and arsenic. Bioremediation of arsenic contaminated waters

  20. Screening and characterization of sex-specific DNA fragments in the freshwater fish matrinchã, Brycon amazonicus (Teleostei: Characiformes: Characidae).

    PubMed

    da Silva, Eder Marques; Wong, Marina Sek Lien; Martins, Cesar; Wasko, Adriane Pinto

    2012-10-01

    The matrinchã Brycon amazonicus, a commercially important freshwater fish resource, has no heteromorphic sex chromosomes so far described. In the present study, we performed a screening of sex-associated DNA markers in this species, through the use of a random amplified polymorphic DNA (RAPD) assay and a genomic DNA restriction digestion analysis. DNA digestions evidenced no differences between sexes. Sixty-six random primers were used in pooled and individual DNA samples of males and females, and the analysis of the RAPD fingerprints revealed one female sex-associated band. Cloning and sequencing of this band led to the identification of two distinct DNA segments. While one of the isolated fragments showed a significant identity with a described protein gene (phosphatidylinositol glycan anchor biosynthesis, class W), the other fragment, composed of 535 bp, corresponds to a novel DNA marker. Further experiments were performed with this second DNA fragment in order to verify its sex-specificity. Data on dot blot hybridization, using total DNA of both sexes, confirmed its female-specificity in B. amazonicus. A primer set was designed based on its sequence data and used in PCR with DNA samples of this species, leading to diagnose the animals' sexes with a 100 % overall accuracy through a sequence characterized amplified region approach. No amplification results were found for two other species of the genus--B. orbignyanus and B. lundii. The obtained data can lead to the hypothesis that B. amazonicus may present heteromorphic sex chromosomes that should be in an early phase of differentiation. PMID:22527611

  1. Assessing species boundaries using multilocus species delimitation in a morphologically conserved group of neotropical freshwater fishes, the Poecilia sphenops species complex (Poeciliidae).

    PubMed

    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-lineag