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Sample records for sailfin silversides telmatherinidae

  1. Physical quality of Simental Ongole crossbred silverside meat at various boiling times

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    Riyanto, J.; Cahyadi, M.; Guntari, W. S.

    2018-03-01

    This study aims to determine the physical quality of silverside beef meat at various boiling times. Samples that have been used are the back thigh or silverside meat. Treatment of boiling meat included TR (meat without boiled), R15 (boiled 15 minutes), and R30 (boiled for 30 minutes). The experimental design using Completely Randomized Design with 3 replications. Each replication was done in triple physical quality test. Determination of physical quality was performed at the Livestock Industry and Processing Laboratory at Sebelas Maret University Surakarta and the Meat Technology Laboratory at the Faculty of Animal Husbandry of Gadjah Mada University. The result of variance analysis showed that boiling affect cooking loss (P≥0.05) and but did not affect (P≤0,05) pH, water holding capacity and meat tenderness. The conclusions of the study showed that boiling for 15 minutes and 30 minutes decreased the cooking loss of Simental Ongole Crossbred silverside meat. Meat physical quality of pH, water holding capacity and the value of tenderness is not affected by boiling for 15 and 30 minutes.

  2. Ecotoxicological tests with cadmium and chromium using postlarvae of silverside Odontesthes (Austromenidia regia regia Hildebrand

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    Giovana Vera

    2014-06-01

    Full Text Available In the present paper, the mean effective concentrations (EC50% of cadmium (Cd+2 and chromium (Cr+6 using postlarvae of the silverside fish Odontesthes (Austromenidia regia regia were determined. The postlarvae were exposed to different concentrations of the metals, between 0,142 and 1,208 mg.L–1 of cadmium and between 0,53 and 33,74 mg.L–1 of chromium. The mean effective concentrations (EC50% obtained were 0,648 mg.L–1 of cadmium (at 96 h and 2,68 mg.L–1 of chromium (at 96 h. Comparatively, cadmium is more toxic than chromium, and silverside is more tolerant than other organisms.

  3. Silversides (Odontesthes bonariensis) reside within freshwater and estuarine habitats, not marine environments

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    Avigliano, Esteban; Miller, Nathan; Volpedo, Alejandra Vanina

    2018-05-01

    Otolith core-to-edge Sr:Ca ratio was determined by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to analyze the salinity-habitat migration history of the silverside, Odontesthes bonariensis, within the Uruguay River (freshwater) and Río de la Plata Estuary (estuarine water) (Plata Basin, South America). Regular core-to-edge oscillations in Sr:Ca suggest that the silverside makes annual migrations between freshwater (1 PSU) habitats, with no evidence of marine incursion or non-migratory individuals. Empirical equations that represent the relationship between conductivity/salinity and otolith Sr:Ca ratio were used to identify where in an otolith an individual transitioned between freshwater and brackish habitats. In most specimens, the first migration between habitats likely occurred within the first year of life. Average numbers of changes between stable Sr:Ca signatures (sites with different salinities) determined by Change-Point analysis were similar from Uruguay River (8.9 ± 3.7) and Río de la Plata Estuary (7.5 ± 2.5) for comparable age fish (p < 0.05), suggesting that habitat use is similar in both collection sites.

  4. Burrowing by Sailfin Catfish (Pterygoplichthys sp.): A Potential Cause of Erosion in Disturbed Environments

    Science.gov (United States)

    2014-03-01

    originates at a large levee, which was built to create a water retention (to control excess water) and water bird management area. The levee and canal...each sample was dried in stainless steel trays in a 60 °C convection oven . Two methods of quantitative analysis were performed to determine the...ERDC/TN ANSRP-14-1 March 2014 Approved for public release; distribution is unlimited. Burrowing by Sailfin Catfish (Pterygoplichthys sp.): A

  5. Parasites of two coexisting invasive sailfin catfishes (Siluriformes: Loricariidae in a tropical region of Mexico

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    María Amparo Rodríguez-Santiago

    Full Text Available ABSTRACT Currently many species of Amazon sailfin catfishes (Loricariidae have been introduced to wild environments outside their native range. There is, however, little knowledge about their role as vectors of parasites that can infect native fish or even humans through its consumption. The aim of the present study was to determine the parasitic fauna of the invasive sailfin catfish species Pterygoplichthys pardalis (leopard pleco and P. disjunctivus (vermiculated pleco from freshwater systems in the southeast of Mexico. Four ectoparasite species were found in P. pardalis (1 protozoan: Ichthyophthirius multifiliis ; 2 monogeneans: Urocleidoides vaginoclastrum and Heteropriapulus heterotylus ; 1 digenean: Clinostomum sp., and only one in Heteropriapulus disjunctivus (H. heterotylus . No endoparasites were found. Ichthyophthirius multifiliis , U. vaginoclaustrum and Clinostomum sp. , were considered as rare species (prevalence <5% since they were found in a single individual of P. pardalis . H. heterotylus was the only species shared among both host species and it occurs throughout the year. This monogenean species represents 96% of total parasites recorded in P. pardalis and 100% in P. disjunctivus. Monthly values of prevalence, intensity and abundance of H. heterotylus in both host species showed important intra-annual variations, but not differ significantly between both hosts.

  6. Regional differentiation and post-glacial expansion of the Atlantic silverside, Menidia menidia, an annual fish with high dispersal potential

    OpenAIRE

    Mach, Megan E.; Sbrocco, Elizabeth J.; Hice, Lyndie A.; Duffy, Tara A.; Conover, David O.; Barber, Paul H.

    2010-01-01

    The coastal marine environment of the Northwest Atlantic contains strong environmental gradients that create distinct marine biogeographic provinces by limiting dispersal, recruitment, and survival. This region has also been subjected to numerous Pleistocene glacial cycles, resulting in repeated extirpations and recolonizations in northern populations of marine organisms. In this study, we examined patterns of genetic structure and historical demography in the Atlantic silverside, Menidia men...

  7. The virtual lover: variable and easily guided 3D fish animations as an innovative tool in mate-choice experiments with sailfin mollies-II. Validation.

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    Gierszewski, Stefanie; Müller, Klaus; Smielik, Ievgen; Hütwohl, Jan-Marco; Kuhnert, Klaus-Dieter; Witte, Klaudia

    2017-02-01

    The use of computer animation in behavioral research is a state-of-the-art method for designing and presenting animated animals to live test animals. The major advantages of computer animations are: (1) the creation of animated animal stimuli with high variability of morphology and even behavior; (2) animated stimuli provide highly standardized, controlled and repeatable testing procedures; and (3) they allow a reduction in the number of live test animals regarding the 3Rs principle. But the use of animated animals should be attended by a thorough validation for each test species to verify that behavior measured with live animals toward virtual animals can also be expected with natural stimuli. Here we present results on the validation of a custom-made simulation for animated 3D sailfin mollies Poecilia latipinna and show that responses of live test females were as strong to an animated fish as to a video or a live male fish. Movement of an animated stimulus was important but female response was stronger toward a swimming 3D fish stimulus than to a "swimming" box. Moreover, male test fish were able to discriminate between animated male and female stimuli; hence, rendering the animated 3D fish a useful tool in mate-choice experiments with sailfin mollies.

  8. The virtual lover: variable and easily guided 3D fish animations as an innovative tool in mate-choice experiments with sailfin mollies-I. Design and implementation.

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    Müller, Klaus; Smielik, Ievgen; Hütwohl, Jan-Marco; Gierszewski, Stefanie; Witte, Klaudia; Kuhnert, Klaus-Dieter

    2017-02-01

    Animal behavior researchers often face problems regarding standardization and reproducibility of their experiments. This has led to the partial substitution of live animals with artificial virtual stimuli. In addition to standardization and reproducibility, virtual stimuli open new options for researchers since they are easily changeable in morphology and appearance, and their behavior can be defined. In this article, a novel toolchain to conduct behavior experiments with fish is presented by a case study in sailfin mollies Poecilia latipinna . As the toolchain holds many different and novel features, it offers new possibilities for studies in behavioral animal research and promotes the standardization of experiments. The presented method includes options to design, animate, and present virtual stimuli to live fish. The designing tool offers an easy and user-friendly way to define size, coloration, and morphology of stimuli and moreover it is able to configure virtual stimuli randomly without any user influence. Furthermore, the toolchain brings a novel method to animate stimuli in a semiautomatic way with the help of a game controller. These created swimming paths can be applied to different stimuli in real time. A presentation tool combines models and swimming paths regarding formerly defined playlists, and presents the stimuli onto 2 screens. Experiments with live sailfin mollies validated the usage of the created virtual 3D fish models in mate-choice experiments.

  9. Evaluation of Reference Genes to Analyze Gene Expression in Silverside Odontesthes humensis Under Different Environmental Conditions

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    Tony L. R. Silveira

    2018-03-01

    Full Text Available Some mammalian reference genes, which are widely used to normalize the qRT-PCR, could not be used for this purpose due to its high expression variation. The normalization with false reference genes leads to misinterpretation of results. The silversides (Odontesthes spp. has been used as models for evolutionary, osmoregulatory and environmental pollution studies but, up to now, there are no studies about reference genes in any Odontesthes species. Furthermore, many studies on silversides have used reference genes without previous validations. Thus, present study aimed to was to clone and sequence potential reference genes, thereby identifying the best ones in Odontesthes humensis considering different tissues, ages and conditions. For this purpose, animals belonging to three ages (adults, juveniles, and immature were exposed to control, Roundup®, and seawater treatments for 24 h. Blood samples were subjected to flow-cytometry and other collected tissues to RNA extraction; cDNA synthesis; molecular cloning; DNA sequencing; and qRT-PCR. The candidate genes tested included 18s, actb, ef1a, eif3g, gapdh, h3a, atp1a, and tuba. Gene expression results were analyzed using five algorithms that ranked the candidate genes. The flow-cytometry data showed that the environmental challenges could trigger a systemic response in the treated fish. Even during this systemic physiological disorder, the consensus analysis of gene expression revealed h3a to be the most stable gene expression when only the treatments were considered. On the other hand, tuba was the least stable gene in the control and gapdh was the least stable in both Roundup® and seawater groups. In conclusion, the consensus analyses of different tissues, ages, and treatments groups revealed that h3a is the most stable gene whereas gapdh and tuba are the least stable genes, even being considered two constitutive genes.

  10. A Spatio-Temporal Model of Phenotypic Evolution in the Atlantic Silverside (Menidia menidia) and Its Implications for Size-Selective Fishing in a Warmer World

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    Sbrocco, E. J.

    2016-02-01

    A pervasive phenotypic pattern observed across marine fishes is that vertebral number increases with latitude. Jordan's Rule, as it is known, holds true both within and across species, and like other ecogeographic principles (e.g., Bergmann's Rule), it is presumed to be an adaptive response to latitudinal gradients in temperature. As such, future ocean warming is expected to impact not only the geographic range limits of marine fishes that conform to Jordan's Rule, but also their phenotype, with warmer waters selecting for fish with fewer vertebrae at any given latitude. Here I present a model of phenotypic evolution over space and time for the Atlantic silverside (Menidia menidia), a common marine fish found in coastal waters along the western North Atlantic. This species has long served as a model organism for the study of fisheries-induced selection and exhibits numerous latitudinal clines in phenotypic and life-history traits, including vertebral number. Common garden experiments have shown that vertebral number is genetically determined in this species, but correlative models of observed vertebral counts and climate reveal that SST is the single strongest predictor of phenotype, even after accounting for gene flow. This result indicates that natural selection is responsible for maintaining vertebral clines in the silverside, and allows for the prediction of phenotypic responses to ocean warming. By integrating genetic estimates of population connectivity, species distribution models, and statistical models, I find that by the end of the 21st century, ocean warming will select for silversides with up to 8% fewer vertebrae. Mid-Atlantic populations are the most mal-adapted for future conditions, but may be rescued by migration from small-phenotype southern neighbors or by directional selection. Despite smaller temperature anomalies, the strongest impacts of warming will be felt at both northern and southern edges of the distribution, where genetic rescue from

  11. Assessment of persistent organic pollutants accumulation and lipid peroxidation in two reproductive stages of wild silverside (Odontesthes bonariensis).

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    Barni, María Florencia Silva; Gonzalez, Mariana; Miglioranza, Karina S B

    2014-01-01

    Persistent organic pollutants (POPs) in streamwater can sometimes exceed the guidelines values reported for biota and human protection in watersheds with intensive agriculture. Oxidative stress and cytotoxicity are some of the markers of exposure to POPs in fish. Accumulation of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) as well as lipid peroxidation (LPO) was assessed in wild silverside (Odontesthes bonariensis) from maturation and pre-spawning stages sampled in a typical soybean growing area. Pollutants were quantified by gas chromatography with electron capture detection and LPO by the method of thiobarbituric acid reactive substances. Concentrations of POPs were in the following order: OCPs>PCBs>PBDEs in all organs and stages. Liver, gills and gonads had the highest OCP concentrations in both sexes and stages with a predominance of endosulfan in all samples. Matured individuals, sampled after endosulfan application period, showed higher endosulfan concentrations than pre-spawning individuals. The predominance of endosulfan sulfate could be due to direct uptake from diet and water column, as well as to the metabolism of the parent compounds in fish. The prevalence of p,p'-DDE in liver would also reflect both the direct uptake and the metabolic transformation of p,p'-DDT to p,p'-DDE by fish. The highest levels of PBDEs and PCBs were found in gills and brain of both stages of growth. The pattern BDE-47>BDE-100 in all samples corresponds to pentaBDE exposure. In the case of PCBs, penta (#101 and 110) and hexa-CB congeners (#153 and 138) dominated in the maturation stages and tri (#18) and tetra-CB (#44 and 52) in pre-spawning stages, suggesting biotransformation or preferential accumulation of heavier congeners during gonadal development. Differences in LPO levels in ovaries were associated with growth dilution and reproductive stage. Differences in LPO levels in gills were related with pesticide

  12. Feeding ecology of the beach silverside Atherinella blackburni (Atherinopsidae in a tropical sandy beach, Southeastern Brazil

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    Júlio Guazzelli Gonzalez

    Full Text Available Abstract The feeding ecology of the beach silverside (Atherinella blackburni in the surf zone of a tropical sand beach, located in the southeastern Brazil, was accessed through the gut content analysis of 198 fish. Factors such as fish's size, season and day period were analysed to understand how these variables affect the diet composition of the species. Results show that A. blackburni is a coastal neritic fish with a broad feeding niche. Most recurrent prey were zooplanktonic crustaceans, insects and benthic molluscs, in which Copepoda crustaceans were the dominant dietary item in occurrence and abundance. A. blackburni appears to have a slight ontogenetic shift in its diet, changing from benthic molluscs to crustaceans and insects along its life cycle. The diel activity also reveals to be an important factor to the A. blackburni feeding ecology. The predominant occurrence of small fish during the morning, along with the main preys for this size class, suggests that small individuals use shallower waters as feeding grounds during the morning and, during the night, they move to deeper waters for protection against predators.

  13. Histological and ultrastructural characteristics of the testis of the invasive suckermouth sailfin catfish Pterygoplichthys disjunctivus (Siluriformes: loricariidae) from Marikina River, Philippines.

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    Jumawan, Joycelyn C; Herrera, Annabelle A

    2015-02-01

    The histological and ultrastructural features of the testis of the invasive suckermouth sailfin catfish Pterygoplichthys disjunctivus rapidly proliferating in Marikina River, Philippines were characterized during the fish's 2010-2011 reproductive season. The germinal compartment of the testes was composed of anastomosing tubules with cysts undergoing synchronous development. Spermatogenic cells were along the length of the testes indicate it to be of the unrestricted spermatogonial type. The spermatozoon is classified as type 1 ect aquasperm devoid of acrosome, has rounded nucleus, and a long flagellum - characteristics necessary for external fertilization. Male P. disjunctivus was reproductively active during half of the year-long study with peak spawning during the most rainy months (June-August) and prolonged recrudescence during the dry months (February-May). Results from this study form a histological baseline to describe the gonad dynamics and reproduction of this invasive fish species as well as provide possible means of mechanical control to curb the population of the fish in this river. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Do different degrees of human activity affect the diet of Brazilian silverside Atherinella brasiliensis?

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    Alves, V E N; Patrício, J; Dolbeth, M; Pessanha, A; Palma, A R T; Dantas, E W; Vendel, A L

    2016-08-01

    The aim of the present study was to test whether different degrees of human activity affect the diet of the Brazilian silverside Atherinella brasiliensis in two tropical estuaries. Fish were collected along the salinity gradient of two Brazilian estuaries, the heavily impacted Paraiba Estuary and the less impacted Mamanguape Estuary, in the dry and wet seasons. The findings confirm that A. brasiliensis has generalist feeding habits and is able to change its diet under different environmental conditions. The results indicate clear spatial (i.e. along the estuarine gradient) changes in diet composition in both estuaries, but diet was also influenced by the degree of anthropogenic disturbance. During the wet season in the nutrient enriched Paraiba Estuary, when human activity was higher, the diet of A. brasiliensis was poorer and dominated by few dietary items, reflecting the potential impoverishment of prey items in this heavily disturbed system. The specimens collected in the most affected estuary also had a greater frequency of micro-plastics and parasites in their stomachs, reflecting the greater degree of human disturbance in the estuary. The present findings suggest that the diet of A. brasiliensis could be a useful indicator of changes in the ecological quality of these and other tropical estuaries of the western Atlantic Ocean. © 2016 The Fisheries Society of the British Isles.

  15. Odontesthes mirinensis, sp.n. um novo peixe-rei (Pisces, Atherinidae, Atherinopsinae para o extremo sul do Brasil Odontesthes mirinensis, sp.n. a new silverside (Pisces, Atherinidae, Atherinopsinae from southern Brazil

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    Marlise de Azevedo Bemvenuti

    1995-01-01

    Full Text Available Odontesthes mirinensis, a new species of silverside, is described in coastal lagoons system of Rio Grande do Sul, Brazil. The new species is distinguished from other Odontesthes species by short snout and having 24-29 gill rakers on the lower branch of the first branchial arch. Osteological features (bones of the skull, axial skeleton and girdles are included and discussed. Meristic and morphometric variables were analyzed separately, through multivariate procedures. Principal Component Analysis show that Odontesthes mirinensis, sp.n. does not exhibit significant geographic variation on body shape.

  16. Growth of the silverside Atherinella brasiliensis in a subtropical estuary with some insights concerning the weight-length relationship

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    BARBARA M. DE CARVALHO

    Full Text Available ABSTRACT Specimens of Brazilian silverside (Atherinella brasiliensis, n=9672 with a length range of 1.5 to 14.2 cm were captured in the intertidal areas of the Estuarine Complex of Paranaguá, Brazil, between August 2010 and July 2011. The species’ weight-length relationship was represented by the equation W=0.00533 L3.136 with a slightly positive allometry (b>3 and could be divided into two growth stanzas: W = W1 + W2; Stanza 1: W1= SW. (0.005239 L3.152; Stanza 2: W2= (1 - SW. (0.000699 L3.913; Switch-Function: SW = [1 + e1.204 (L - 11.66]-1. The breakpoint between the first and second stanza (11.66 cm matches published values for the estimated size at first maturity of adult females. Frequency distributions indicate that the species is present in the shallow areas of the Estuarine Complex of Paranaguá during all phases of its ontogenetic development, with the recruitment of juveniles taking place between October and November. Modal displacement was monitored throughout 12 months. The von Bertalanffy growth model and longevity was estimated as follow: asymptotic length (L∞ of 17.5 cm, growth coefficient (K of 0.89 (year-1 and longevity (A95 of 3.33 years. We present some considerations with regard to the general methodology for adjusting weight-length relationships.

  17. Biological aspects of the Sailfin dory Zenopsis conchifer (Lowe, 1852 caught by deep-sea trawling fishery off southern Brazil

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    Rodrigo Silvestre Martins

    2012-06-01

    Full Text Available Biological aspects of sailfin dory, Zenopsis conchifer, were studied from 839 individuals obtained from deep-sea commercial bottom trawling off southern Brazil at depths up to 526 m in 2002 and 2003. Samples included fish from 101 mm Lt and 15 g up to 640 mm Lt and 2,9 g. The sex-ratio was 50% at 150 mm Lt and between 300-350 mm Lt, with females outnumbering males in the remaining size classes. Reproductive activity seems to peak between July and August (austral winter. Size at attainment of 50% maturity (Lt50 was 311 mm Lt in females. The mean length and maturity of the specimens increased with depth, suggesting that larger fish concentrate in deeper waters.Aspectos biológicos do peixe-galo-de-profundidade, Zenopsis conchifer, foram estudados a partir de 839 peixes amostrados na pesca comercial de arrasto de profundidade (até 526 m no sul do Brasil entre 2002 e 2003. As amostras incluíram peixes entre 101 mm TL e 15 g até 640 mm TL e 2.952 g. A proporção sexual foi próxima à paridade na classe de tamanho de 150 mm TL e entre 300-350 mm TL, sendo que as fêmeas predominaram nas demais classes. A atividade reprodutiva apresentou um pico durante o inverno. O tamanho de primeira maturação (TL50 nas fêmeas foi de 311 mm TL. Os comprimentos corporais e a maturidade sexual aumentaram com a profundidade, sugerindo que os maiores exemplares se concentram águas profundas.

  18. Hábito alimentar e osteologia da boca do peixe-rei, Odontesthes humensis de Buen (Atheriniformes, Atherinopsidae na Lagoa Mirim, Rio Grande do Sul, Brasil Feeding habits and mouth osteology of silverside, Odontesthes humensis de Buen (Atheriniformes, Atherinopsidae in the Mirim Lagoon, Rio Grande do Sul, Brazil

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    Fábio Lameiro Rodrigues

    2001-09-01

    Full Text Available Gut contents of 304 individuals of the silverside Odontesthes humensis de Buen, 1953 were analyzed using frequency of occurrence (FO% and gravimetric (P% methods. A total of 207 individuals (68.1% had some food itens in the gut, while 97 individuals (31.9% had empty guts. The silverside Odontesthes humensis has presented a benthic carnivorous diet, preying mainly on molluscs and arthropods. The molluscs Heleobia sp. (FO = 61.35% and Corbicula fluminea (Müller, 1774 (FO = 57.97% were the most frequent itens, followed by Neocorbicula limosa (Maton, 1811 (FO = 17.39%. Among the arthropods, the coleoptera insects (FO= 18.84% were dominant followed by, insect larvae (FO = 6.76%, the crustacean Palaemonetes argentinus Nobili, 1901 (FO = 1.93% and isopods (FO = 1.45%. Vegetal remains, organic matter and digested fish were grouped due to low frequency (FO = 9.13% being considered occasional. Juvenile fed mainly on insect larvae and moluscs, while the adults preferred molluscs and coleoptera. On the description of its feeding apparatus the importance of a protrusible upper jaw was observed, being important on the capture of prey in inaccessible places. A protrusible mouth and the format of the pharingean plates, are important morphological characters that assist on the capture and handling of prey. The molariform shaped pharingean teeth help break hard food items, as shells and carapaces.

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

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    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. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  20. Progress in the development of short term chronic toxicity testing methods for crude oil and commercial bioremediation agents

    International Nuclear Information System (INIS)

    Cavender, R.C.; Cherry, D.S.; Dobbs, M.G.; Bidwell, J.R.; Yeager, M.M.

    1995-01-01

    Proposed modifications to the National Oil and Hazardous Substance Pollution Contingency Plan (NCP) have prompted examinations of the methodology used in toxicity testing of the water soluble fraction of oil, commercial bioremediation agents (CBA), and a combination of the two. The specific concerns addressed by this research are the use of unweathered Alaska North Slope (ANS) crude oil instead of the more expensive, less environmentally realistic distillate ANS-521, and the appropriate laboratory preparation methodology for the water soluble fraction (WSF) used in testing. Seven-day chronic tests exposing the inland silverside (Menidia beryllina) and estuarine mysid (Mysidopsis bahia) to the water soluble fraction of unweathered ANS and ANS-521 showed that mysids responded similarly to the two types of oils while silversides were more sensitive to unweathered ANS. In the presence of a CBA and WSF, the mortality of the organisms and the mysid growth were similar in both types of oil. The NOEC for silverside growth, however, was lower in the combined exposure of a CBA with ANS-521 WSF than it was in the CBA-WSF unweathered ANS. Testing is underway to determine if the stirring time length effects the toxicity of the WSF, or the WSF and CBA combination. In chronic tests using both the silverside and mysid there were no differences in growth and mortality of the organisms tested in WSF prepared from 10 and 20 hours of stirring, however, the 5 hour stirring exposure is less toxic to both organisms

  1. Recrutamento do peixe-rei, Atherinella brasiliensis (Quoy & Gaimard (Atheriniformes, Atherinopsidae, na margem continental da Baía de Sepetiba, Rio de Janeiro, Brasil Recruitament of the silverside, Atherinella brasiliensis (Quoy & Gaimard (Atheriniformes, Atherinopsidae, in continental margin of Sepetiba Bay, Rio de Janeiro, Brazil

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    André Luiz Machado Pessanha

    2001-12-01

    Full Text Available The silverside, Atherinella brasiliensis (Quoy & Gaimard, 1824, a resident species of the shallows of bays, estuaries and coastal lagoons, was studied during two annual cycles, using beach seines (July 1996 to June 1998, in the continental margin of the Sepetiba Bay, aiming to assess recruitment and distribution patterns. A wide recruitment period, with young-of-the-year appearing from early spring to early autumn, was shown, with peaks of juveniles (Total Length-LT = 10-30 mm being recorded in two periods of the year; one in November and another in March. The highest abundances, of both juvenile and adults, were recorded in Coroa Grande and Itacuruçá, sites located in the outer Bay, during the whole summer, with significant differences were found. In spite of not having been found any statistically significant relationship between the environmental factors and the occurrence of this species, a trend of higher abundance in colder and more saline waters was detected. High values of growth coefficient (K = 0.93 and low asymptotic lenght (L∞ = 11.6 cm indicated that this species shows a high growth rate and short life cycle, with life span of 3.09 years, in this system.

  2. Heavy Metal Content in Chilean Fish Related to Habitat Use, Tissue Type and River of Origin.

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    Copaja, S V; Pérez, C A; Vega-Retter, C; Véliz, D

    2017-12-01

    In this study, we analyze the concentration of ten metals in two freshwater fish-the benthic catfish Trichomycterus areolatus and the limnetic silverside Basilichthys microlepidotus-in order to detect possible accumulation differences related to fish habitat (benthic or pelagic), tissue type (gill, liver and muscle), and the river of origin (four different rivers) in central Chile. The MANOVA performed with all variables and metals, revealed independent effects of fish, tissue and river. In the case of the fish factor, Cu, Cr, Mo and Zn showed statistically higher concentrations in catfish compared with silverside for all tissues and in all rivers (p food sources and respiration.

  3. Age and growth of three Odontesthes species from Southern Brazil (Atherinopsidae, with reference to phylogenetic constraints in their life-history

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    Becker F. G.

    2003-01-01

    Full Text Available The age and growth of three silverside species are described, and a discussion on possible phylogenetic constraints on life-history characteristics is presented. Samples were collected monthly between March 1992 and February 1993 in three freshwater coastal lakes. Standard length-total length (Ls-Lt and weight-length (Wt-Lt relationships studied showed interspecific differences in comparisons between juveniles and adults, males and females. Age was determined by scales. The three species presented a life-cycle duration of 4 to 5 years, with growth coefficients values (K between 0.37 and 0.63, and asymptotic lengths between 211 and 257 mm. Some interspecific differences may be useful for distinguishing between species (sexual and life-stage related patterns in Ls-Lt and Wt-Lt. The observed life-cycle ranges and maximum sizes were compared to those of other silversides and revealed a pattern coherent with available phylogenetic hypotheses at the supra-generic level, indicating that some life-history characteristics may be subject to phylogenetic constraints.

  4. Comparison of feeding strategies in acute toxicity tests of crude oil and commercial bioremediation agents

    International Nuclear Information System (INIS)

    Cavender, R.C.; Cherry, D.S.; Yeager, M.M.; Bidwell, J.R.

    1995-01-01

    Proposed modifications to the National Oil and Hazardous Substance Pollution Contingency Plan have prompted examinations of the methodology used in toxicity testing of the water soluble fraction (WSF) of oil, commercial bioremediation agents (CBA), and a combination of the two. The organisms currently used in acute (96 hr) testing of these agents are the inland silverside, Menidia beryllina, and an estuarine mysid, Mysidopsis bahia. The mysid is a carnivorous species that must be fed during a test in order to prevent predation within the test chambers. Currently proposed methodology for silverside testing also includes feeding. The high oxygen demand of CBAs and the WSF of oil causes dissolved oxygen to be a factor in toxicity. This effect can be intensified by the addition of brine shrimp (Artemia sp.) to the test chambers. The purpose of this study was to compare the toxicity of CBAs in combination with the WSF of oil to silversides with and without the addition of food. Tests were conducted using both 24-hour and 14-day spinning times for the CBA/WSF mixture. With the 24-hour spinning time, LC50 values from each day of the 4-day test were consistently lower in the Artemia fed test (47.8--22.6%) as compared to the unfed test (72.1--43.0%). A similar trend was seen in the 24 and 48 hour LC50's in the 14-day spinning time. Overall, low dissolved oxygen was found to be most relevant at the highest CBA/WSF concentrations where D.O. dropped below 2 mg/l in Artemia fed tests

  5. Fisheries and Limnological Studies on West Point Reservoir, Alabama-Georgia. Phase IV.

    Science.gov (United States)

    1984-05-01

    This is seemingly due to the irregular fishing effort and catch during the winter as dictated by the vagaries of the weather. To substantially increase...Agri. Exp. Stat. Bull. 477. 21 pp. Echelle, A. A., and J. B. Mense . 1968. Forage value of Mississippi silverside in Lake Texoma. Proc. Okla. Acad. Sci

  6. Trophic relationships of small nonnative fishes in a natural creek and several agricultural drains flowing into the Salton Sea, and their potential, effects on the endangered desert pupfish

    Science.gov (United States)

    Martin, Barbara A.; Saiki, Michael K.

    2009-01-01

    This study was conducted to characterize trophic relationships of small nonnative fishes and to determine if predation by these fishes contributes to the decline of desert pupfish (Cyprinodon macularius), an endangered cyprinodont on the verge of extinction. We sampled 403 hybrid Mozambique tilapias (Oreochromis mossambica by O. urolepis), 107 redbelly tilapias (Tilapia zillii), 32 longjaw mudsuckers (Gillkhthys mirabilis), 182 western mosquitofish (Gambusia affinis), 222 sailfin mollies (Poecilia latipinna), 63 shortfin mollies (Poecilia mexicana), and 235 porthole livebearers (Poecilurpsis gracilis) from a natural creek and four agricultural drains during September 1999- December 2001. Evidence of piscivory was in gastrointestinal contents of 14 hybrid Mozambique tilapias, 3 redbelly tilapias, 10 longjaw mudsuckers, 8 western mosquitofish, 2 sailfin mollies, and 8 porthole livebearers. Although digestion often was too advanced for identification of fishes consumed by nonnative fishes, remains of desert pupfish were in gastrointestinal contents of a longjaw mudsucker. Our findings, along with Field evidence from other studies that inverse relationships exist between abundances of desert pupfish and nonnative species, are consistent with the hypothesis that predation by nonnative species is contributing to decline of desert pupfish. We suspect that competitive interactions with nonnative fishes might also adversely affect abundance of desert pupfish.

  7. Prey fish returned to Forster's tern colonies suggest spatial and temporal differences in fish composition and availability.

    Science.gov (United States)

    Peterson, Sarah H; Ackerman, Joshua T; Eagles-Smith, Collin A; Herzog, Mark P; Hartman, C Alex

    2018-01-01

    Predators sample the available prey community when foraging; thus, changes in the environment may be reflected by changes in predator diet and foraging preferences. We examined Forster's tern (Sterna forsteri) prey species over an 11-year period by sampling approximately 10,000 prey fish returned to 17 breeding colonies in south San Francisco Bay, California. We compared the species composition among repeatedly-sampled colonies (≥ 4 years), using both relative species abundance and the composition of total dry mass by species. Overall, the relative abundances of prey species at seven repeatedly-sampled tern colonies were more different than would be expected by chance, with the most notable differences in relative abundance observed between geographically distant colonies. In general, Mississippi silverside (Menidia audens) and topsmelt silverside (Atherinops affinis) comprised 42% of individuals and 40% of dry fish mass over the study period. Three-spined stickleback (Gasterosteus aculeatus) comprised the next largest proportion of prey species by individuals (19%) but not by dry mass (6%). Five additional species each contributed ≥ 4% of total individuals collected over the study period: yellowfin goby (Acanthogobius flavimanus; 10%), longjaw mudsucker (Gillichthys mirabilis; 8%), Pacific herring (Clupea pallasii; 6%), northern anchovy (Engraulis mordax; 4%), and staghorn sculpin (Leptocottus armatus; 4%). At some colonies, the relative abundance and biomass of specific prey species changed over time. In general, the abundance and dry mass of silversides increased, whereas the abundance and dry mass of three-spined stickleback and longjaw mudsucker decreased. As central place foragers, Forster's terns are limited in the distance they forage; thus, changes in the prey species returned to Forster's tern colonies suggest that the relative availability of some fish species in the environment has changed, possibly in response to alteration of the available habitat.

  8. Prey fish returned to Forster’s tern colonies suggest spatial and temporal differences in fish composition and availability

    Science.gov (United States)

    Peterson, Sarah; Ackerman, Joshua T.; Eagles-Smith, Collin A.; Herzog, Mark; Hartman, C. Alex

    2018-01-01

    Predators sample the available prey community when foraging; thus, changes in the environment may be reflected by changes in predator diet and foraging preferences. We examined Forster’s tern (Sterna forsteri) prey species over an 11-year period by sampling approximately 10,000 prey fish returned to 17 breeding colonies in south San Francisco Bay, California. We compared the species composition among repeatedly-sampled colonies (≥ 4 years), using both relative species abundance and the composition of total dry mass by species. Overall, the relative abundances of prey species at seven repeatedly-sampled tern colonies were more different than would be expected by chance, with the most notable differences in relative abundance observed between geographically distant colonies. In general, Mississippi silverside (Menidia audens) and topsmelt silverside (Atherinops affinis) comprised 42% of individuals and 40% of dry fish mass over the study period. Three-spined stickleback (Gasterosteus aculeatus) comprised the next largest proportion of prey species by individuals (19%) but not by dry mass (6%). Five additional species each contributed ≥ 4% of total individuals collected over the study period: yellowfin goby (Acanthogobius flavimanus; 10%), longjaw mudsucker (Gillichthys mirabilis; 8%), Pacific herring (Clupea pallasii; 6%), northern anchovy (Engraulis mordax; 4%), and staghorn sculpin (Leptocottus armatus; 4%). At some colonies, the relative abundance and biomass of specific prey species changed over time. In general, the abundance and dry mass of silversides increased, whereas the abundance and dry mass of three-spined stickleback and longjaw mudsucker decreased. As central place foragers, Forster’s terns are limited in the distance they forage; thus, changes in the prey species returned to Forster’s tern colonies suggest that the relative availability of some fish species in the environment has changed, possibly in response to alteration of the available

  9. Selectividad del zooplancton y solapamiento trófico entre tallas del pez Menidia humboldtiana (Atheriniformes: Atherinopsidae en el embalse Danxhó, México

    Directory of Open Access Journals (Sweden)

    Regina Sánchez Merino

    2009-06-01

    Full Text Available El charal Menidia humboldtiana es considerado como una de las especies de gran importancia en la industria pesquera de algunos estados de México. Es necesario conocer el efecto que esta especie ejerce sobre su alimento para saber si seleccionan las presas de mayor talla, si hay competencia por el alimento entre especies nativas e introducidas, y para comprender el comportamiento del zooplancton ante peces zooplanctófagos. Se determinó si M. humboldtiana selecciona su alimento, sobre qué géneros lo hace, y si existe traslape en la dieta entre las diferentes tallas. Los peces se recolectaron por medio de un chinchorro de 88 mm de abertura de malla, en seis estaciones de muestreo durante un año, en el embalse Danxhó, y una muestra de zooplancton fue recolectada por filtrado con una red de 125 µm. El análisis de los contenidos estomacales se realizó en peces agrupados en intervalos de longitud estándar para cada época del año, por medio del método volumétrico. Para evaluar el traslape trófico entre los diferentes intervalos de longitud, se utilizó el índice de Morisita modificado por Horn. El zooplancton estuvo representado por doce géneros: Mastigodiaptomus y Cyclops (Copepoda; Bosmina, Diaphanosoma, Daphnia, Ceriodaphnia, Moina, Alonopsis y Camptocercus (Cladocera; Asplanchna, Conochillus y Filinia (Rotifera. Durante la primavera, los charales de 3-8.9 cm presentaron un marcado traslape, para el verano fueron los grandes (7-10.9 cm, en otoño el traslape fue en todas las tallas, y en invierno solo las tallas intermedias (5-8.9 cm lo presentaron.Selectivity of zooplankton and trophic overlap between size Menidia humboldtiana fish (Atheriniformes: Atherinopsidae in the reservoir Danxhó, Mexico. The Menidia humboldtiana silverside is considered one of the most important species in fisheries in some states of Mexico. Knowing the choice that this species exercises over its food gives us an understanding of the behavior of

  10. Simulating the indirect effects of power plant entrainment losses on an estuarine ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Summers, J.K. (Versar, Inc., Columbia, MD (USA))

    1989-12-01

    Entrainment caused by the operation of the Chalk Point Steam Electric Station has been shown to be a major source of mortality to the early life stages of forage fish populations in the Patuxent River, MD, USA. While direct losses to these populations are important as a source of reduction for population abundance, these losses also represent decreases in estuarine forage supplies and potential reductions in the abundances of estuarine predators. A simple estuarine trophic dynamics model was constructed to determine the magnitude of the potential losses to major estuarine consumers in the Patuxent River ecosystem due to the power plant-related losses of forage fish. Simulations were completed using two sets of feeding assumptions: feeding proportional to forage abundance, and feeding based on dietary preferences. The model demonstrates that striped bass, bluefish, and weakfish could experience significant losses (> 25%) to overall population production levels if they prefer to prey upon bay anchovy and silversides and entrainment losses to these forage populations is {>=} 70% of juvenile recruitment. The model also shows that indirect predator losses would be expected to be low (> 5%) if the majority of their diets consisted of forage other than bay anchovy and silversides. 2 figs., 31 refs., 4 tabs.

  11. Temperature, energy acquisition and energy use in the Chilean silverside Basilichthys australis Eigenmann (Atherinopsidae Temperatura, adquisición de energía y uso de energía en el pejerrey chileno Basilichthys australis Eigenmann (Atherinopsidae

    Directory of Open Access Journals (Sweden)

    LEOPOLDO FUENTES

    2005-06-01

    Full Text Available We evaluated the influence of water temperature (Tw on the energy acquisition and use in the chilean silverside Basilichthys australis (Eigenmann 1927, an endemic species inhabiting freshwater ecosystems in Chile. We tested the effect of Tw (11.5, 14.0, 18.0, 22.0 and 26.0 °C on food intake, digestibility, food transit time and metabolic rate. As expected, this study demonstrated that many physiological variables under study were significantly affected by Tw, as well as the net energy balance of this species. Nevertheless, the net energy balance was not strictly related to the range of Tws evaluated. At Tws lower than 14 °C the energy budget was depressed, because food intake was lower than at Tws between 14 and 26 °C, where food intake was higher and independent of Tw. Consequently, at these temperatures the energy balance was positive and also independent of Tw. Physiologically, B. australis appears to be a tolerant species with respect to the wide range of water temperature in habitats at different depths. Thus, its distributions may extend through the entire profile of lakes and rivers, even in systems characterised by spatial and temporal thermal variabilityEn este trabajo evaluamos la influencia de la temperatura del agua (Ta en la adquisición de energía y su uso por parte del pejerrey chileno Basilichthys australis (Eigenmann 1927, una especie endémica que habita los ecosistemas dulceacuícolas de Chile. Investigamos el efecto de Ta (11,5, 14,0, 18,0, 22,0 y 26,0 °C en la ingesta de alimento, digestibilidad, tiempo de transito del alimento y tasa metabólica. De acuerdo a lo esperado, este estudio demostró que varias de las variables fisiológicas bajo estudio fueron significativamente afectadas por Ta, así como el balance energético de esta especie. Sin embargo, el balance neto de energía no estuvo estrictamente relacionado al rango de Tas evaluadas. En Tas inferiores a 14 °C el presupuesto de energía fue deprimido, debido a

  12. Uso do manguezal de Guaratiba, Baía de Sepetiba, Rio de Janeiro, pelo peixe-rei Atherinella brasiliensis (Quoy & Gaimard (Atheriniformes, Atherinopsidae The use of the Guaratiba magrove, Sepetiba Bay, Rio de Janeiro, by the silverside Atherinella brasiliensis (Quoy & Gaimard (Atheriniformes, Atherinopsidae

    Directory of Open Access Journals (Sweden)

    Leonardo M. Neves

    2006-06-01

    Full Text Available Coletas padronizadas de peixes e tomadas de variáveis ambientais foram realizadas em uma região de mangue na Baía de Sepetiba visando avaliar o papel deste sistema no ciclo de vida do peixe-rei Atherinella brasiliensis (Quoy & Gaimard, 1824. Um programa de amostragens mensais de arrastos de praia foi realizado, em cinco locais em uma área de mangue, entre agosto de 2002 e julho de 2003 nos períodos diurno e noturno, com variáveis ambientais tendo sido tomadas em cada local. As maiores abundâncias numéricas foram registradas no local da zona intermediária do canal principal, e as menores no local mais interno. As maiores contribuições em peso ocorreram no local mais externo e próximo da conexão com o mar. A abundância numérica foi diretamente correlacionada com a temperatura e salinidade, e o peso, com a salinidade e oxigênio dissolvido (p Fish and environmental variables were sampled in a mangrove area from Sepetiba bay to assess the role of this system in life cycle of the silverside Atherinella brasiliensis (Quoy & Gaimard, 1824. Standardized monthly sampling using beach seines were conducted at five sites, between August, 2002 and July, 2003 in daily (day/night basis, with environmental variables being taken at each site. The highest numerical abundance was recorded in the intermediate sample area in the mangrove channel and the lowest in the innermost site. The highest weight occurred in the outermost site near to the sea connection. Numerical abundance was directly correlated with temperature and salinity, and weight with salinity and dissolved oxygen (p < 0.05. Size ranged from 10 to 160 mm TL, with modes of 40-50 mm TL occurring all over the year in all sites. Recruitment occurred all year round but peaks (TL = 30 mm in October-December, 2002 and July, 2003 were recorded afterwards the records of larger fishes (September, 2002 and June, 2003 mainly in the outermost site. The largest fishes concentrated in the sandy

  13. Presence of trace elements in fishes from the Chaco-Pampeana plain (Argentina

    Directory of Open Access Journals (Sweden)

    Alejandra V. Volpedo

    2015-06-01

    Full Text Available The Chaco-Pampean plain is one of the greatest plains worldwide; present a wetland macro system (lagoons, marshes, rivers, streams, channels. The water quality of these environments is diverse and has different trace elements natural (As, F, Mo and V and anthropogenic (Cr, Cu and Pb. The Chaco Pampean plain has an important diversity of fish species however the species of commercial importance are limited. This paper presents the reviews of the studies related to the presence of trace elements in tissues of commercial fishes (shad Prochilodus lineatus and silversides Odontesthes bonariensis in the Chaco-Pampean plain in recent decades and a discussion about associated information gaps is presented. The presence of trace elements in commercial fish muscle is a major problem for food security. The results showed that most of the elements present in shad are in lower levels than the maximum limits set by the Argentine Food Code (CAA, 2014. In the case of Pb present in the muscle of the shad, the determined values exceed those considered by the European Food Safety Authority. In the case of silversides the values of As, Pb, Hg are mostly lower than those maximum recommended by the Argentine Food Code. However, according to the European Food Safety Authority, the lower limit on the benchmark dose for a 10% response (BMDL values associated with health risk for As.

  14. Marine effect of introduced salmonids: Prey consumption by exotic steelhead and anadromous brown trout in the Patagonian Continental Shelf

    Science.gov (United States)

    Ciancio, J.; Beauchamp, D.A.; Pascual, M.

    2010-01-01

    On the basis of stable isotope analysis, we estimated the marine diet of the most abundant anadromous salmonid species in Patagonian Atlantic basins. The results were coupled with bioenergetic and population models to estimate the consumption of food by salmonids and was compared with that by seabirds, the most abundant top predators in the area. Amphipods were the main salmonid prey, followed by sprat, silversides, squid, and euphausiids. The total consumption, even assuming large anadromous salmonid populations, represented Limnology and Oceanography, Inc.

  15. Biotransferencia de fluor a distintos tejidos de pejerreyes (Odontesthes bonariensis)

    OpenAIRE

    Volpedo, Alejandra; Puntoriero, María Laura; Fernandez Cirelli, Alicia

    2016-01-01

    The presence of fluorine (F), toxic trace element, has relevance in the trophic chain because it can biotrasfer to different levels. It can come from water as food, being chronic ingestion harmful to human beings. Fluorine was found in different water bodies of southwest of Buenos Aires. Chasicó Lake has the highest fluorine concentration. This water body is the most important for commercial and recreational fishing silverside (Odontesthes bonariensis) of the area. The aim of this paper is to...

  16. Biotransferencia de flúor de agua a diferentes tejidos de pejerrey (Odontotesthes bonariensis)

    OpenAIRE

    Puntoriero, María Laura; Volpedo, Alejandra; Fernández Cirelli, Alicia

    2014-01-01

    The presence of fluorine (F), toxic trace element, has relevance in the trophic chain because it can biotrasfer to different levels. It can come from water as food, being chronic ingestion harmful to human beings. Fluorine was found in different water bodies of southwest of Buenos Aires. Chasicó Lake has the highest fluorine concentration. This water body is the most important for commercial and recreational fishing silverside (Odontesthes bonariensis) of the area. The aim of this paper is to...

  17. Toxicity of common ions to marine organisms

    International Nuclear Information System (INIS)

    Pillard, D.A.; DuFresne, D.L.; Evans, J.

    1995-01-01

    Produced waters from oil and gas drilling operations are typically very saline, and these may cause acute toxicity to marine organisms due to osmotic imbalances as well as to an excess or deficiency of specific common ions. In order to better understand the relationship between toxicity and ion concentration, laboratory toxicity tests were conducted using mysid shrimp (Mysidopsis bahia), sheepshead minnow (Cyprinodon variegatus), and inland silverside (Menidia beryllina). For each species the ionic concentration of standard laboratory water was proportionally increased or decreased to produce test solutions with a range of salinities. Organisms were exposed for 48 hours. Individual ions (sodium, potassium, calcium, magnetsium, strontium, chloride, bromide, sulfate, bicarbonate, and borate) were also manipulated to examine individual ion toxicity. The three test species differ in their tolerance of salinity. Mysid shrimp show a marked decrease in survival at salinities less than approximately 5 ppt. Both fish species tolerated low salinity water, however, silversides were less tolerant of saline waters (salinity greater than 40 ppt). There were also significant differences in the responses of the organisms to different ions. The results show that the salinity of the test solution may play an important role in the responses of the organisms to the produced water effluent. Predictable toxicity/ion relationships developed in this study can be used to estimate whether toxicity in a produced water is a result of common ions, salinity, or some other unknown toxicant

  18. Potential of Pigeon Creek, San Salvador, Bahamas, as Nursery Habitat for Juvenile Reef Fish

    Directory of Open Access Journals (Sweden)

    Conboy, Ian Christopher

    2011-10-01

    Full Text Available This project assessed the significance of Pigeon Creek, San Salvador, Bahamas as a nursery habitat for coral reef fishes. Pigeon Creek’s perimeter is lined with mangrove and limestone bedrock. The bottom is sand or seagrass and ranges in depth from exposed at low tide to a 3-m deep, tide-scoured channel. In June 2006 and January 2007, fish were counted and their maturity was recorded while sampling 112 of 309 possible 50-m transects along the perimeter of the Pigeon Creek. Excluding silversides (Atherinidae, 52% of fish counted, six families each comprised >1% of the total abundance (Scaridae/parrotfishes, 35.3%; Lutjanidae/snappers, 23.9%; Haemulidae/grunts, 21.0%; Gerreidae/mojarras, 8.5%; Pomacentridae/damselfishes, 6.1%; Labridae/wrasses, 2.4%. There were few differences in effort-adjusted counts among habitats (mangrove, bedrock, mixed, sections (north, middle, southwest and seasons (summer 2006 and winter 2007. Red Mangrove (Rhizophora mangle, covering 68% of the perimeter was where 62% of the fish were counted. Snappers, grunts and parrotfishes are important food fishes and significant families in terms of reef ecology around San Salvador. Mangrove was the most important habitat for snappers and grunts; bedrock was most important for parrotfishes. The southwest section was important for snappers, grunts and parrotfishes, the north section for grunts and parrotfishes, and the middle section for snappers. Among the non-silverside fish counted, 91.2% were juveniles. These results suggest that Pigeon Creek is an important nursery for the coral reefs surrounding San Salvador and should be protected from potential disturbances.

  19. Effect of ageing time in vacuum package on veal longissimus dorsi and biceps femoris physical and sensory traits

    Directory of Open Access Journals (Sweden)

    G. Baldi

    2015-09-01

    Full Text Available Study evaluated the effects of vacuum ageing (2, 4, 6, 8, 10, 12, 16 days on veal loin (longissimus dorsi; LD and silverside (biceps femoris; BF physical and sensory characteristics. Ageing did not affect cooking loss, increased LD pH and L*, a* and b* in both muscles. Shear force (SF decreased until day 6 in LD and day 10 in BF. Aroma, flavor and taste were not affected, while texturetraits were improved. SF was negative correlated with tenderness and juiciness and positive correlated with BF fibrousness and stringy sensation. Ageing improved texture properties withoutaltering other sensory traits.

  20. Organic pollutant levels in an agricultural watershed: the importance of analyzing multiple matrices for assessing stream water pollution.

    Science.gov (United States)

    Gonzalez, Mariana; Miglioranza, Karina S B; Grondona, Sebastían I; Silva Barni, Maria Florencia; Martinez, Daniel E; Peña, Aránzazu

    2013-04-01

    This study is aimed at analyzing the occurrence and transport of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the Quequén Grande river basin, as representative of a catchment under diffuse pollution sources. Pollutant levels in soils, river bottom sediments (RBS), streamwater (Sw), suspended particle materials (SPMs), macrophytes and muscle of silverside were determined by GC-ECD. Soil K(d) values for the current-used insecticides, endosulfans and cypermethrin, were established. Total levels (ng g(-1) dry weight) in soil ranged between 0.07–0.9 for OCPs, 0.03–0.37 for PCBs and 0.01–0.05 for PBDEs. Endosulfan insecticide (α- + b- + sulfate metabolite) represented up to 72.5% of OCPs. The low soil retention for α-endosulfan (K(d): 77) and endosulfan sulfate (K(d): 100) allows their transport to Sw, SPM and RBS. Levels of endosulfan in Sw in some cases exceeded the value postulated by international guidelines for aquatic biota protection (3 ng L(-1)). PCB and PBDE pollution was related to harbour, dumping sites and pile tire burning. Tri and hexa PCB congeners predominated in all matrices and exceeded the quality guideline value of 0.04 ng L(-1) in Sw. Considering levels in silverside muscle, none of the oral reference doses were exceeded, however, PCBs accounted for 18.6% of the total daily allowed ingest for a 70 kg individual. Although the levels of PCBs and OCPs in soil and RBS were low and did not go beyond quality guidelines, these compounds could still represent a risk to aquatic biota and humanbeings, and thus actions towards preventing this situation should be undertaken.

  1. A new species of Limnoderetrema (Trematoda, Digenea from the freshwater Atherinid fish Basilichthys australis Eigenmann, 1927 from the south of Chile

    Directory of Open Access Journals (Sweden)

    Patricio Torres

    1991-12-01

    Full Text Available Limnoderetrema tolosai sp. n. (Trematoda, Digenea within an autochthonous freshwater fish, the silverside Basilichthys autralis Eigenmann, 1927, from Lakes Riñihue and Ranco in Southern Chile is described. The species is distinguished from Limnoderetrema minutum (Manter, 1954 by the presence of one spine in the cirrus and cecal bifurcation nearer to ventral sucker than to pharinx. It is proposed Limnoderetrema macrophallus (Szidat & Nani, 1951 n. comb. (originally Steganoderma. Limnoderetrema tolosai differs from L. macrophallus since it cirrus has a distal spine and by its vitelline follicles distribution. It seems that Limnoderetrema spp. of South America are highly specific unlike L. minutum of New Zealand.

  2. Feeding of Hoplias aff. malabaricus (Bloch, 1794 and Oligosarcus robustus Menezes, 1969 in a lagoon under estuarine influence, Pelotas, RS

    Directory of Open Access Journals (Sweden)

    Fabiano Corrêa

    2009-09-01

    Full Text Available The objective of the present paper was to study the diets of Hoplias aff. malabaricus and Oligosarcus robust in “Pequena Lagoon” and evaluate the importance of estuarine organisms in the feeding of freshwater fish. A total of twelve food categories were identified and it was established that the fish resource was the most frequent in the diet of both species. Euryhaline fish such as Mugil platanus mullets and Odontesthes argentinensis silversides were common items in the diets of these two species, which included not only freshwater fish but also euryhaline fish from the adjacent estuarine zone, integrating both resources in the food chain.

  3. The role of P450 metabolism in the estrogenic activity of bifenthrin in fish.

    Science.gov (United States)

    DeGroot, Breanna C; Brander, Susanne M

    2014-11-01

    Bifenthrin, a pyrethroid pesticide, is estrogenic in vivo in fishes. However, bifenthrin is documented to be anti-estrogenic in vitro, in the ER-CALUX (estrogen receptor) cell line. We investigated whether metabolite formation is the reason for this incongruity. We exposed Menidia beryllina (inland silversides) to 10ng/l bifenthrin, 10ng/l 4-hydroxy bifenthrin, and 10ng/l bifenthrin with 25μg/l piperonyl butoxide (PBO) - a P450 inhibitor. Metabolite-exposed juveniles had significantly higher estrogen-mediated protein levels (choriogenin) than bifenthrin/PBO-exposed, while bifenthrin alone was intermediate (not significantly different from either). This suggests that metabolites are the main contributors to bifenthrin's in vivo estrogenicity. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Sequencing and characterization of the guppy (Poecilia reticulata transcriptome

    Directory of Open Access Journals (Sweden)

    Rodd F Helen

    2011-04-01

    a congeneric species, the sailfin molly (Poecilia latipinna. Over 40% of reads from the sailfin molly sample aligned to the guppy transcriptome. Conclusions We show that next-generation sequencing provided a reliable and broad reference transcriptome. This resource allowed us to identify candidate gene variants, SNPs in coding regions, and sex-specific gene expression, and permitted quantitative analysis of differential gene expression.

  5. Unusual dominance by desert pupfish (Cyprinodon macularius) in experimental ponds within the Salton Sea Basin

    Science.gov (United States)

    Saiki, Michael K.; Martin, Barbara A.; Anderson, Thomas W.

    2011-01-01

    In October 2006, months after shallow experimental ponds in the Salton Sea Basin were filled with water from the Alamo River and Salton Sea, fish were observed in several ponds, although inlets had been screened to exclude fish. During October 2007November 2009, nine surveys were conducted using baited minnow traps to document species and relative abundance of fish. Surveys yielded 3,620 fish representing five species. Desert pupfish (Cyprinodon macularius), the only native species encountered, was the most numerous and comprised >93% of the catch. Nonnative species included western mosquitofish (Gambusia affinis, 4.1%), sailfin molly (Poecilia latipinna, 2.8%), and tilapia (a mixture of hybrid Mozambique tilapia Oreochromis mossambicus ?? O. urolepis and redbelly tilapia Tilapia zillii, <0.1%). Dominance by desert pupfish, which persisted over our 2 years of study, was unusual because surveys conducted in nearby agricultural drains yielded relatively few desert pupfish.

  6. Oocyte structure and ultrastructure in the Mexican silverside fish Chirostoma humboldtianum (Atheriniformes: Atherinopsidae

    Directory of Open Access Journals (Sweden)

    Rodolfo Cárdenas

    2008-12-01

    Full Text Available the structural and ultrastructural features of gonads from endemic Mexican fish have received scarce attention. This study describes the histological and ultrastructural characteristics of the oocyte in Chirostoma humboldtianum. The ovary is asynchronic, and as such, most phases of oocyte development are found in the same ovary. The complete process of oogenesis was divided in five stages: oogonium and folliculogenesis, primary growth, cortical alveoli and lipid inclusions, vitellogenesis and maturation. The presence of big filaments, which appear at the end of primary growth, induces some common follicular adaptation. During primary growth, abundant ribosomes, rough endoplasmic reticulum, and mitochondria are grouped in the cytoplasm. At the end of this stage, the Z1 layer of the chorion is developed, while microvilli start to be evident as well. In the cortical alveoli and lipid droplets phase, intense PAS positive vesicles, some of them containing nucleoid material, are observed in the peripheral cytoplasm and the lipid droplets take a more central position. In vitellogenesis, the proteic yolk accumulates in a centripetal way while the chorion is completely formed. In maturation, the germinal vesicle migrates to the animal pole, meiosis is restored, and there is nuclear breakdown. The oocyte increases its size and holds some oil droplets and a big fluid mass of yolk. On the outside, filaments surround the oocyte completely. Rev. Biol. Trop. 56 (4: 1825-1835. Epub 2008 December 12.Los aspectos estructurales y ultraestructrurales de las gónadas de peces mexicanos endémicos han sido poco estudiados. En el presente trabajo reportamos las características histológicas y ultraestructurales del ovocito de Chirostoma hulmboldtianum. El ovario es de tipo asincrónico, por ende, la mayoría de las fases del desarrollo del ovocito pueden ser encontradas en el mismo ovario. El desarrollo del ovocito fue dividido en cinco etapas: ovo-gonia y foliculogénesis, crecimiento primario del ovocito, inclusiones lipídicas y gránulos corticales, vitelogénesis y maduración. La presencia de grandes filamentos que aparecen al final de la etapa de crecimiento primario, inducen adaptaciones foliculares. Durante el crecimiento primario, en el citoplasma se encuentran abundantes ribosomas, retículo endoplásmico rugoso y agrupamientos de mitocondrias. Al final de esta etapa, inicia el desarrollo de la capa Z1 del corion, comenzando a ser evidentes las microvellosidades del ovocito. Durante la etapa de inclusiones lipídicas y gránulos corticales, vesículas PAS positivas, algunas de ellas con material nucleoide, se ubican en la periferia del ovocito, mientras que las que contienen material graso toman una posición más central en la célula. Durante la vitelogénesis se presenta una acumulación de vitelo protéico en un sentido centrípeto; durante esta etapa, el corion está completamente formado. En la maduración, la vesicular germinal migra hacia el polo animal, se reinicia la meiosis y se rompe la envoltura nuclear. El ovocito incrementa su tamaño y en el citoplasma se pueden observar algunas gotas de grasa y el vitelo se presenta como una gran masa acuosa. En el exterior, los filamentos rodean completamente al ovocito.

  7. Purification and characterization of chymotrypsin from viscera of vermiculated sailfin catfish, Pterygoplichthys disjunctivus, Weber, 1991.

    Science.gov (United States)

    Villalba-Villalba, Ana Gloria; Ramírez-Suárez, Juan Carlos; Pacheco-Aguilar, Ramón; Valenzuela-Soto, Elisa Miriam; Lugo-Sánchez, María Elena; Figueroa-Soto, Ciria Guadalupe

    2013-04-01

    Pterygoplichthys disjunctivus viscera chymotrypsin was purified by fractionation with ammonium sulfate (30-70 % saturation), gel filtration, affinity, and ion exchange chromatography. Chymotrypsin molecular weight was approximately 29 kDa according to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), shown a single band in zymogram. Electrofocusing study suggested being an anionic enzyme (pI ≈ 3.9), exhibiting maximal activity at pH 9 and 50 °C, using Suc-Ala-Ala-Pro-Phe-p-nitroanilide (SAAPNA) as substrate. Enzyme was effectively inhibited by phenyl methyl sulfonyl fluoride (PMSF) (99 %), and N-tosyl-L-phenylalanine chloromethyl ketone (TPCK) (94 %). Enzyme activity was affected by the following ions in decreasing order: Hg(2+), Fe(2+), Cu(2+), Li(1+), Mg(2+), K(1+), Mn(2+), while Ca(2+) had no effect. Chymotrypsin activity decreased continuously as NaCl concentration increased (from 0 to 30 %). K m and V max values were 0.72 ± 1.4 mM and 1.15 ± 0.06 μmol/min/mg of protein, respectively (SAAPNA as substrate). Results suggest the enzyme has a potential application where low processing temperatures are needed, such as in fish sauce production.

  8. Trypsin from viscera of vermiculated sailfin catfish, Pterygoplichthys disjunctivus, Weber, 1991: its purification and characterization.

    Science.gov (United States)

    Villalba-Villalba, Ana Gloria; Ramírez-Suárez, Juan Carlos; Valenzuela-Soto, Elisa Miriam; Sánchez, Guillermina García; Ruiz, Gisela Carvallo; Pacheco-Aguilar, Ramón

    2013-11-15

    Pterygoplichthys disjunctivus viscera trypsin was purified by fractionation with ammonium sulphate, gel filtration, affinity and ion exchange chromatography (DEAE-Sepharose). Trypsin molecular weight was approximately 27.5kDa according to SDS-PAGE, shown a single band in zymography. It exhibited maximal activity at pH 9.5 and 40°C, using N-benzoyl-dl-arginine-p-nitroanilide (BAPNA) as substrate. Enzyme was effectively inhibited by phenyl methyl sulphonyl fluoride (PMSF) (100%), N-α-p-tosyl-l-lysine chloromethyl ketone (TLCK) (85.4%), benzamidine (80.2%), and soybean trypsin inhibitor (75.6%) and partially inhibited by N-tosyl-l-phenylalanine chloromethyl ketone (TPCK) (10.3%), ethylendiaminetetraacetic acid (EDTA) (8.7%) and pepstatin A (1.2%). Enzyme activity was slightly affected by metal ions (Fe(2+)>Hg(2+)>Mn(2+)>K(+)>Mg(2+)>Li(+)>Cu(2+)). Trypsin activity decreased continuously as NaCl concentration increased (0-30%). Km and kcat values were 0.13mM and 1.46s(-1), respectively. Results suggest the enzyme have a potential application where room processing temperatures (25-35°C) or high salt (30%) concentration are needed, such as in fish sauce production. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Does Reproductive Investment Decrease Telomere Length in Menidia menidia?

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    Jin Gao

    Full Text Available Given finite resources, intense investment in one life history trait is expected to reduce investment in others. Although telomere length appears to be strongly tied to age in many taxa, telomere maintenance requires energy. We therefore hypothesize that telomere maintenance may trade off against other life history characters. We used natural variation in laboratory populations of Atlantic silversides (Menidia menidia to study the relationship between growth, fecundity, life expectancy, and relative telomere length. In keeping with several other studies on fishes, we found no clear dependence of telomere length on age. However, we did find that more fecund fish tended to have both reduced life expectancy and shorter telomeres. This result is consistent with the hypothesis that there is a trade-off between telomere maintenance and reproductive output.

  10. Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, April and July 2007

    Science.gov (United States)

    May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

    2007-01-01

    This report presents the results for two sampling periods during a 4-year monitoring survey to provide a characterization of selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species, and total suspended solids were determined in water samples, and total selenium was determined in sediment, detritus, and biota that included algae, plankton, midge larvae (family, Chironomidae), and two fish species-western mosquitofish (Gambusia affinis), and sailfin molly (Poecilia latipinna). In addition, sediments were analyzed for percent total organic carbon and particle size. Total selenium concentrations in water for both sampling periods ranged from 1.43 to 47.1 micrograms per liter, predominately as selenate, which is typical of waters leached out of selenium-contaminated marine shales under alkaline and oxidizing conditions. Total selenium concentrations ranged from 0.88 to 20.2 micrograms per gram in biota, and from 0.15 to 28.9 micrograms per gram in detritus and sediment.

  11. Introgression between ecologically distinct species following increased salinity in the Colorado Delta- Worldwide implications for impacted estuary diversity.

    Science.gov (United States)

    Lau, Clive L F; Jacobs, David K

    2017-01-01

    We investigate hybridization and introgression between ecologically distinct sister species of silverside fish in the Gulf of California through combined analysis of morphological, sequence, and genotypic data. Water diversions in the past century turned the Colorado River Delta from a normal estuary to a hypersaline inverse estuary, raising concerns for the local fauna, much of which is endangered. Salinity differences are known to generate ecological species pairs and we anticipated that loss of the fresher-water historic salinity regime could alter the adaptive factors maintaining distinction between the broadly distributed Gulf-endemic Colpichthys regis and the narrowly restricted Delta-endemic Colpichthys hubbsi , the species that experienced dramatic environmental change. In this altered environmental context, these long-isolated species (as revealed by Cytochrome b sequences) show genotypic (RAG1, microsatellites) evidence of active hybridization where the species ranges abut, as well as directional introgression from C. regis into the range center of C. hubbsi . Bayesian group assignment (STRUCTURE) on six microsatellite loci and multivariate analyses (DAPC) on both microsatellites and phenotypic data further support substantial recent admixture between the sister species. Although we find no evidence for recent population decline in C. hubbsi based on mitochondrial sequence, introgression may be placing an ancient ecological species at risk of extinction. Such introgressive extinction risk should also pertain to other ecological species historically sustained by the now changing Delta environment. More broadly, salinity gradient associated ecological speciation is evident in silverside species pairs in many estuarine systems around the world. Ecological species pairs among other taxa in such systems are likely poorly understood or cryptic. As water extraction accelerates in river systems worldwide, salinity gradients will necessarily be altered, impacting

  12. Introgression between ecologically distinct species following increased salinity in the Colorado Delta- Worldwide implications for impacted estuary diversity

    Directory of Open Access Journals (Sweden)

    Clive L.F. Lau

    2017-12-01

    Full Text Available We investigate hybridization and introgression between ecologically distinct sister species of silverside fish in the Gulf of California through combined analysis of morphological, sequence, and genotypic data. Water diversions in the past century turned the Colorado River Delta from a normal estuary to a hypersaline inverse estuary, raising concerns for the local fauna, much of which is endangered. Salinity differences are known to generate ecological species pairs and we anticipated that loss of the fresher-water historic salinity regime could alter the adaptive factors maintaining distinction between the broadly distributed Gulf-endemic Colpichthys regis and the narrowly restricted Delta-endemic Colpichthys hubbsi, the species that experienced dramatic environmental change. In this altered environmental context, these long-isolated species (as revealed by Cytochrome b sequences show genotypic (RAG1, microsatellites evidence of active hybridization where the species ranges abut, as well as directional introgression from C. regis into the range center of C. hubbsi. Bayesian group assignment (STRUCTURE on six microsatellite loci and multivariate analyses (DAPC on both microsatellites and phenotypic data further support substantial recent admixture between the sister species. Although we find no evidence for recent population decline in C. hubbsi based on mitochondrial sequence, introgression may be placing an ancient ecological species at risk of extinction. Such introgressive extinction risk should also pertain to other ecological species historically sustained by the now changing Delta environment. More broadly, salinity gradient associated ecological speciation is evident in silverside species pairs in many estuarine systems around the world. Ecological species pairs among other taxa in such systems are likely poorly understood or cryptic. As water extraction accelerates in river systems worldwide, salinity gradients will necessarily be

  13. Lower lethal temperatures for nonnative freshwater fishes in Everglades National Park, Florida

    Science.gov (United States)

    Schofield, Pam; Kline, Jeffrey L.

    2018-01-01

    Temperature is an important factor that shapes biogeography and species composition. In southern Florida, the tolerance of nonnative freshwater fishes to low temperatures is a critical factor in delineating their geographic spread. In this study, we provide empirical information on experimentally derived low-temperature tolerance limits of Banded Cichlid Heros severus and Spotfin Spiny Eel Macrognathus siamensis, two nonnative Everglades fishes that were lacking data, and African Jewelfish Hemichromis letourneuxi and Mayan Cichlid Cichlasoma urophthalmus, species for which previous results were derived from studies with small sample sizes. We also provide a literature review summarizing the current state of knowledge of low-temperature tolerances for all 17 nonnative freshwater fishes that have been found in Everglades National Park. Mean lower lethal temperature tolerances ranged from 4°C (Orinoco Sailfin Catfish Pterygoplichthys multiradiatus) to 16.1°C (Butterfly Peacock Bass Cichla ocellaris). These low-temperature limits may inform the understanding of the ecological role or influence of nonnative fishes and may lead to potential management opportunities and applications.

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

    Directory of Open Access Journals (Sweden)

    ML Martins

    Full Text Available 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.

  15. Fish kairomones induce spine elongation and reduce predation in marine crab larvae.

    Science.gov (United States)

    Charpentier, Corie L; Wright, Alexander J; Cohen, Jonathan H

    2017-08-01

    Specialized defense strategies are induced in zooplankton upon detection of predator chemical cues or kairomones. These defenses are well-described for freshwater zooplankters, with morphological defenses being particularly striking, but few studies have reported kairomone-induced morphological defenses in marine zooplankton. Here, we compare morphological responses to kairomones in the larvae of two marine crab species, estuarine mud crabs (Rhithropanopeus harrisii) and Asian shore crabs (Hemigrapsus sanguineus). When reared in the presence of fish kairomones, spine length increased by 2-3% in larval R. harrisii, while no morphological changes were identified in H. sanguineus. In subsequent feeding assays with a co-occurring fish predator (Atlantic silversides, Menidia menidia), consumption of R. harrisii was lower on larvae that had been reared with kairomones. In addition, we found that broods with smaller larvae are more likely to exhibit increases in spine length after kairomone exposure. Hence, the observed morphological response is likely influenced by larval size. © 2017 by the Ecological Society of America.

  16. Mortality in captive wild-caught horned puffin chicks (Fratercula corniculata).

    Science.gov (United States)

    Tocidlowski, M E; Cornish, T E; Loomis, M R; Stoskopf, M K

    1997-09-01

    Sixteen horned puffin (Fratercula corniculata) and six parakeet auklet (Cyclorrhynchus psittacula) chicks of various prefledging ages were caught in Alaska and transported to the North Carolina Zoological Park (USA) in August 1995. Six of the 16 puffin chicks died within a 5-day period beginning 2 days after their arrival into quarantine at the zoo. The birds that died were collected at a young age, weighed 45.4-65.7 g, and had been fed a diet of thawed frozen ocean silversides (Atherinidae) that was not supplemented with vitamins. Clinical signs were nonspecific, and gross necropsies, insecticide toxicology screens, and bacterial cultures were unremarkable. Microscopic examination of tissues from five of the six birds showed myocardial necrosis and degeneration suggestive of vitamin E deficiency and intestinal protozoa resembling Microsporidia. The mortality pattern and histopathologic lesions observed in this case support the use of selective age capture and vitamin supplementation for wild alcid chick collection.

  17. Natural growth, otolith shape and diet analyses of Odontesthes nigricans Richardson (Atherinopsidae) from southern Patagonia

    Science.gov (United States)

    Lattuca, M. E.; Lozano, I. E.; Brown, D. R.; Renzi, M.; Luizon, C. A.

    2015-12-01

    Age and growth, otolith shape and diet of Odontesthes nigricans were analysed in order to provide an insight into the life history of the species and furthermore, to assess their possible use as a tool for discriminating silverside populations from the South Atlantic Ocean (Punta María) and Beagle Channel waters (Varela Bay). The age and growth analysis was performed by counting daily increments and annual marks in sagittae otoliths. Length-at-age data of individuals Otolith shape variation was also explored using elliptical Fourier analysis and it showed significant differences between Varela Bay and Punta María populations. Furthermore, gut content analysis characterized O. nigricans as an invertebrate predator, being benthic organisms the most important components of its diet, which also showed significant site dependence. The use of all these analyses contributed to a holistic approach which maximized the likelihood of correctly identifying both O. nigricans populations in the southernmost limit of the species distribution.

  18. Surfing among species, populations and morphotypes: Inferring boundaries between two species of new world silversides (Atherinopsidae).

    Science.gov (United States)

    González-Castro, Mariano; Rosso, Juan José; Mabragaña, Ezequiel; Díaz de Astarloa, Juan Martín

    2016-01-01

    Atherinopsidae are widespread freshwater and shallow marine fish with singular economic importance. Morphological, genetical and life cycles differences between marine and estuarine populations were already reported in this family, suggesting ongoing speciation. Also, coexistence and interbreeding between closely related species were documented. The aim of this study was to infer boundaries among: (A) Odontesthes bonariensis and O. argentinensis at species level, and intermediate morphs; (B) the population of O. argentinensis of Mar Chiquita Lagoon and its marine conspecifics. To achieve this, we integrated, meristic, Geometrics Morphometrics and DNA Barcode approaches. Four groups were discriminated and subsequently characterized according to their morphological traits, shape and meristic characters. No shared haplotypes between O. bonariensis and O. argentinensis were found. Significative-meristic and body shape differences between the Mar Chiquita and marine individuals of O. argentinensis were found, suggesting they behave as well differentiated populations, or even incipient ecological species. The fact that the Odontesthes morphotypes shared haplotypes with both, O. argentinensis and O. bonariensis, but also possess meristic and morphometric distinctive traits open new questions related to the origin of this morphogroup. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  19. Prevalence of Centrocestus formosanus Metacercariae in Ornamental Fish from Chiang Mai, Thailand, with Molecular Approach Using ITS2.

    Science.gov (United States)

    Wanlop, Atcharaphan; Wongsawad, Chalobol; Prattapong, Pongphol; Wongsawad, Pheravut; Chontananarth, Thapana; Chai, Jong-Yil

    2017-08-01

    The prevalence of Centrocestus formosanus metacercariae was investigated in ornamental fish purchased from a pet shop in Chiang Mai, Thailand, including Carassius auratus (goldfish), Cyprinus carpio (Koi), Poecilia latipinna (Sailfin Molly), Danio rerio (Zebrafish), and Puntigrus tetrazona (Tiger barb). The parasite species was identified by the morphology of worms as well as by a molecular approach using ITS2. The results showed that 50 (33.3%) of 150 fish examined were infected with the metacercariae. The highest prevalence was found in C. auratus (83.3%), and the highest intensity was noted in C. carpio (70.8 metacercariae/fish). The most important morphological character was the presence of 32-34 circumoral spines on the oral sucker. The phylogenetic studies using the rRNA ITS2 region revealed that all the specimens of C. formosanus in this study were grouped together with C. formosanus in GenBank database. This is the first report on ornamental fish, C. carpio, P. latipinna, D. rerio, and P. tetrazona, taking the role of second intermediate hosts of C. formosanus in Thailand. Prevention and control of metacercarial infection in ornamental fish is urgently needed.

  20. Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, October 2008 and January 2009

    Science.gov (United States)

    May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

    2009-01-01

    This report presents the results for two sampling periods (October 2008 and January 2009) during a 4-year monitoring program to characterize selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species (dissolved selenite, selenate, organoselenium), and total suspended solids were determined in water samples. Total selenium also was determined in water column particulates and in sediment, detritus, and biota that included algae, plankton, midge larvae (family, Chironomidae), and two fish species (western mosquitofish, Gambusia affinis, and sailfin molly, Poecilia latipinna). In addition, sediments were analyzed for percent total organic carbon and particle size. Mean total selenium concentrations in water for both sampling periods ranged from 1.00 to 33.6 micrograms per liter, predominately as selenate, which is typical of waters where selenium is leached out of selenium-containing marine shales and associated soils under alkaline and oxidizing conditions. Total selenium concentrations (micrograms per gram dry weight) ranged as follows: algae, 1.52 to 8.26; plankton, 0.79 to 3.66; midges, 2.68 to 50.6; fish, 3.09 to 30.4; detritus, 1.78 to 58.0; and sediment, 0.42 to 10.0.

  1. Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, April and July 2008

    Science.gov (United States)

    May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

    2009-01-01

    This report presents the results for two sampling periods (April 2008 and July 2008) during a 4-year monitoring program to characterize selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species (dissolved selenite, selenate, organoselenium), and total suspended solids were determined in water samples and total selenium was determined in water column particulates and in sediment, detritus, and biota that included algae, plankton, midge larvae (family, Chironomidae), and two fish species - western mosquitofish (Gambusia affinis) and sailfin molly (Poecilia latipinna). In addition, sediments were analyzed for percent total organic carbon and particle size. Mean total selenium concentrations in water for both sampling periods ranged from 1.93 to 44.2 micrograms per liter, predominately as selenate, which is typical of waters where selenium is leached out of selenium-containing marine shales and associated soils under alkaline and oxidizing conditions. Total selenium concentrations (micrograms per gram dry weight) ranged as follows: algae, 0.75 to 3.39; plankton, 0.88 to 4.03; midges, 2.52 to 44.3; fish, 3.37 to 18.9; detritus, 1.11 to 13.6; sediment, 0.11 to 8.93.

  2. Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, October 2007 and January 2008

    Science.gov (United States)

    May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

    2008-01-01

    This report presents the results for two sampling periods (October 2007 and January 2008) during a 4-year monitoring program to characterize selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species (selenite, selenate, organoselenium), and total suspended solids were determined in water samples, and total selenium was determined in sediment, detritus, and biota that included algae, plankton, midge larvae (family, Chironomidae), and two fish species?western mosquitofish (Gambusia affinis) and sailfin molly (Poecilia latipinna). In addition, sediments were analyzed for percent total organic carbon and particle size. Mean total selenium concentrations in water for both sampling periods ranged from 0.97 to 64.5 micrograms per liter, predominately as selenate, which is typical of waters where selenium is leached out of selenium-containing marine shales and associated soils under alkaline and oxidizing conditions. Total selenium concentrations (micrograms per gram dry weight) ranged as follows: algae, 0.95 to 5.99; plankton, 0.15 to 19.3; midges, 1.39 to 15.4; fish, 3.71 to 25.1; detritus, 0.85 to 21.7; sediment, 0.32 to 7.28.

  3. Tests for oil/dispersant toxicity: In situ laboratory assays

    International Nuclear Information System (INIS)

    Wright, D.A.; Coelho, G.M.; Aurand, D.V.

    1995-01-01

    As part of its readiness program in oil spill response, the Marine Pollution Control Unit (MPCU), Department of Transport, U.K. conducts annual field trials in the North Sea, approximately 30 nautical miles from the southeast coast of England. The trials take the form of controlled releases of crude oil or Medium Fuel/Gas Oil mix (MFO), with and without the application of Corexit 9527 dispersant. In 1994 and 1995 the authors conducted a series of in situ toxicity bioassays in association with these spills with included 48h LC50 tests for turbot (Scophthalmus maximus) and oyster (Crassostrea gigas) larvae, a 48 h oyster (C. gigas) embryonic development test and two full life-cycle assays using the copepods Acartia tonsa and Tisbe battagliai. Tests were also conducted in the Chesapeake Bay laboratory using estuarine species including the copepod Eurytemora affinis and the inland silverside Menidia beryllina. Here, the authors report on the results of these assays, together with 1996 in situ toxicity data resulting from Norwegian field trials in the northern North Sea

  4. A rop net and removable walkway used to quantitatively sample fishes over wetland surfaces in the dwarf mangrove of the Southern Everglades

    Science.gov (United States)

    Lorenz, J.J.; McIvor, C.C.; Powell, G.V.N.; Frederick, P.C.

    1997-01-01

    We describe a 9 m2 drop net and removable walkways designed to quantify densities of small fishes in wetland habitats with low to moderate vegetation density. The method permits the collection of small, quantitative, discrete samples in ecologically sensitive areas by combining rapid net deployment from fixed sites with the carefully contained use of the fish toxicant rotenone. This method requires very little contact with the substrate, causes minimal alteration to the habitat being sampled, samples small fishes in an unbiased manner, and allows for differential sampling of microhabitats within a wetland. When used in dwarf red mangrove (Rhizophora mangle) habitat in southern Everglades National Park and adjacent areas (September 1990 to March 1993), we achieved high recovery efficiencies (78–90%) for five common species <110 mm in length. We captured 20,193 individuals of 26 species. The most abundant fishes were sheepshead minnowCyprinodon variegatus, goldspotted killifishFloridichthys carpio, rainwater killifishLucania parva, sailfin mollyPoecilia latipinna, and the exotic Mayan cichlidCichlasoma urophthalmus. The 9 m2 drop net and associated removable walkways are versatile and can be used in a variety of wetland types, including both interior and coastal wetlands with either herbaceous or woody vegetation.

  5. Final Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin, California

    Science.gov (United States)

    Saiki, Michael K.; Martin, Barbara A.; May, Thomas W.

    2010-01-01

    This report summarizes comprehensive findings from a 4-year-long field investigation to document baseline environmental conditions in 29 agricultural drains and ponds operated by the Imperial Irrigation District along the southern border of the Salton Sea. Routine water-quality collections and fish community assessments were conducted on as many as 16 sampling dates at roughly quarterly intervals from July 2005 to April 2009. The water-quality measurements included total suspended solids and total (particulate plus dissolved) selenium. With one exception, fish were surveyed with baited minnow traps at quarterly intervals during the same time period. However, in July 2007, fish surveys were not conducted because we lacked permission from the California Department of Fish and Game for incidental take of desert pupfish (Cyprinodon macularius), an endangered species. During April and October 2006-08, water samples also were collected from seven intensively monitored drains (which were selected from the 29 total drains) for measurement of particulate and dissolved selenium, including inorganic and organic fractions. In addition, sediment, aquatic food chain matrices [particulate organic detritus, filamentous algae, net plankton, and midge (chironomid) larvae], and two fish species (western mosquitofish, Gambusia affinis; and sailfin molly, Poecilia latipinna) were sampled from the seven drains for measurement of total selenium concentrations. The mosquitofish and mollies were intended to serve as surrogates for pupfish, which we were not permitted to sacrifice for selenium determinations. Water quality (temperature, dissolved oxygen, pH, specific conductance, and turbidity) values were typical of surface waters in a hot, arid climate. A few drains exhibited brackish, near-anoxic conditions, especially during summer and fall when water temperatures occasionally exceeded 30 degrees Celsius. Total selenium concentrations in water were directly correlated with salinity and

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

    Science.gov (United States)

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

    2014-11-01

    The trophic interactions between 15 native and two introduced fish species, silverside Odontesthes bonariensis and rainbow trout Oncorhynchus mykiss, collected in a major fishery area at Lake Titicaca were explored by integrating traditional ecological knowledge and stable-isotope analyses (SIA). SIA suggested the existence of six trophic groups in this fish community based on δ(13)C and δ(15)N signatures. This was supported by ecological evidence illustrating marked spatial segregation between groups, but a similar trophic level for most of the native groups. Based on Bayesian ellipse analyses, niche overlap appeared to occur between small O. bonariensis (<90 mm) and benthopelagic native species (31.6%), and between the native pelagic killifish Orestias ispi and large O. bonariensis (39%) or O. mykiss (19.7%). In addition, Bayesian mixing models suggested that O. ispi and epipelagic species are likely to be the main prey items for the two introduced fish species. This study reveals a trophic link between native and introduced fish species, and demonstrates the utility of combining both SIA and traditional ecological knowledge to understand trophic relationships between fish species with similar feeding habits. © 2014 The Fisheries Society of the British Isles.

  7. Testing Wallace's intuition: water type, reproductive isolation and divergence in an Amazonian fish.

    Science.gov (United States)

    Pires, Tiago H S; Borghezan, Elio A; Machado, Valeria N; Powell, Daniel L; Röpke, Cristhiana P; Oliveira, Claudio; Zuanon, Jansen; Farias, Izeni P

    2018-06-01

    Alfred Russel Wallace proposed classifying Amazon rivers based on their colour and clarity: white, black and clear water. Wallace also proposed that black waters could mediate diversification and yield distinct fish species. Here, we bring evidence of speciation mediated by water type in the sailfin tetra (Crenuchus spilurus), a fish whose range encompasses rivers of very distinct hydrochemical conditions. Distribution of the two main lineages concords with Wallace's water types: one restricted to the acidic and nutrient-poor waters of the Negro River (herein Rio Negro lineage) and a second widespread throughout the remaining of the species' distribution (herein Amazonas lineage). These lineages occur over a very broad geographical range, suggesting that despite occurring in regions separated by thousands of kilometres, individuals of the distinct lineages fail to occupy each other's habitats, hundreds of metres apart and not separated by physical barrier. Reproductive isolation was assessed in isolated pairs exposed to black-water conditions. All pairs with at least one individual of the lineage not native to black waters showed significantly lower spawning success, suggesting that the water type affected the fitness and contributed to reproductive isolation. Our results endorse Wallace's intuition and highlight the importance of ecological factors in shaping diversity of the Amazon fish fauna. © 2018 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2018 European Society For Evolutionary Biology.

  8. A quantitative genetic approach to assess the evolutionary potential of a coastal marine fish to ocean acidification

    KAUST Repository

    Malvezzi, Alex J.

    2015-02-01

    Assessing the potential of marine organisms to adapt genetically to increasing oceanic CO2 levels requires proxies such as heritability of fitness-related traits under ocean acidification (OA). We applied a quantitative genetic method to derive the first heritability estimate of survival under elevated CO2 conditions in a metazoan. Specifically, we reared offspring, selected from a wild coastal fish population (Atlantic silverside, Menidia menidia), at high CO2 conditions (~2300 μatm) from fertilization to 15 days posthatch, which significantly reduced survival compared to controls. Perished and surviving offspring were quantitatively sampled and genotyped along with their parents, using eight polymorphic microsatellite loci, to reconstruct a parent-offspring pedigree and estimate variance components. Genetically related individuals were phenotypically more similar (i.e., survived similarly long at elevated CO2 conditions) than unrelated individuals, which translated into a significantly nonzero heritability (0.20 ± 0.07). The contribution of maternal effects was surprisingly small (0.05 ± 0.04) and nonsignificant. Survival among replicates was positively correlated with genetic diversity, particularly with observed heterozygosity. We conclude that early life survival of M. menidia under high CO2 levels has a significant additive genetic component that could elicit an evolutionary response to OA, depending on the strength and direction of future selection.

  9. Aquatic food webs in mangrove and seagrass habitats of Centla Wetland, a Biosphere Reserve in Southeastern Mexico

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    Manuel Mendoza-Carranza

    Full Text Available Mangrove and seagrass habitats are important components of tropical coastal zones worldwide, and are conspicuous habitats of Centla Wetland Biosphere Reserve (CWBR in Tabasco, Mexico. In this study, we examine food webs in mangrove- and seagrass-dominated habitats of CWBR using stable isotope ratios of carbon and nitrogen. Our objective was to identify the importance of carbon derived from mangroves and seagrasses to secondary production of aquatic consumers in this poorly studied conservation area. Carbon and nitrogen isotope ratios of basal sources and aquatic consumers indicated that the species-rich food webs of both habitats are dependent on riparian production sources. The abundant Red mangrove Rhizophora mangle appears to be a primary source of carbon for the mangrove creek food web. Even though dense seagrass beds were ubiquitous, most consumers in the lagoon food web appeared to rely on carbon derived from riparian vegetation (e.g. Phragmites australis. The introduced Amazon sailfin catfish Pterygoplichthys pardalis had isotope signatures overlapping with native species (including high-value fisheries species, suggesting potential competition for resources. Future research should examine the role played by terrestrial insects in linking riparian and aquatic food webs, and impacts of the expanding P. pardalis population on ecosystem function and fisheries in CWBR. Our findings can be used as a baseline to reinforce the conservation and management of this important reserve in the face of diverse external and internal human impacts.

  10. Efeito in vitro de químicos no crescimento micelial de Saprolegnia spp. In vitro effect of chemical on hyphal growth of Saprolegnia spp.

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    Bruna Ferraz Corrêa

    2013-06-01

    agents that are "environmentally friendly". The aim of this study was to evaluate the in vitro susceptibility of 12 isolates of Saprolegnia spp. from the silversides Odontesthes bonariensis and O. humensis. Susceptibility tests evaluating inhibition of mycelial growth of Saprolegnia spp. were performed using six chemicals (sodium chloride, formaldehyde, potassium permanganate, povidone-iodine, sea salt and iodized sea salt in concentrations from 0 to 10,000ppm. The results displayed that formaldehyde at the concentration of 10ppm, and potassium permanganate at concentrations above 100ppm, were able to inhibit the mycelial growth of isolates of Saprolegnia spp. However, povidone-iodine and saline compounds exhibited no antimicrobial activity on Saprolegnia spp. Although the in vitro results showed that formaldehyde and potassium permanganate could be promising in controlling saprolegniosis, further studies should be performed to evaluate the in vivo efficacy of these compounds as well as to verify the toxicity of the chemicals to the silversides O. bonariensis and O. humensis.

  11. Consecutive repetition of lordosis-kyphosis in silverside Atherina boyeri Risso, 1810 collected from a wild population in Homa Lagoon, Izmir, Turkey

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    Jawad Laith

    2017-06-01

    Full Text Available The incidence of severe consecutive repetition of lordosis-kyphosis involving three flexions was reported in a specimen of the atherinid fish Atherina boyeri Risso. The values for the angles lay between the lines passing through the sides of the vertebral column and enclosing the curvatures, and the depth of the curvatures of the angles was obtained. Also, the ratio of the vertebral column to the fish total length of deformed and normal specimens of this species was calculated. Possible causes for these anomalies are discussed.

  12. Diet and trophic ecomorphology of the silverside, Odontesthes bonariensis, of the Salto Caxias reservoir, rio Iguaçu, Paraná, Brazil

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    Fernanda Aparecida da Silva Cassemiro

    Full Text Available This study aims to analyze the diet and trophic ecomorphology of Odontesthes bonariensis, relating these features with species' abundance in the natural environment and in the Salto Caxias reservoir (at Iguaçu river after the reservoir's formation. The samples were carried out before (from March 1997 to February 1998- pre and after (from October 1998 to February 2001 - post 1 and 2 the damming. The stomach contents of 218 individuals were analyzed by occurrence and volumetric methods. O. bonariensis' diet is based on insects, scales, plants and detritus. Microcrustaceans (Cladocera and Copepoda were the main items, allowing the characterization of the species as zooplanktivore. The species has a superior position and protractible mouth, with small teeth, creating a serrated pattern, uniformly lined side by side. There are many gill rakers, that are long and close together (typical of filtering fishes; the stomach is ill defined and the intestine is short. There was a gradual increase of O. bonariensis' abundance during the period of field study, mainly after the second year of damming. This fact seems to be closely related with the high abundance and availability of zooplankton in the dammed environment, and also with the ability of the species to exploit this resource.

  13. Composition and diversity of ichthyofauna in La Viña reservoir (Córdoba, Argentina

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    M. Mancini

    Full Text Available Several dams have been built in central and north Argentina. There are more than 20 reservoirs in Córdoba province, with a total estimated surface area of around 15,000 ha. Although construction of dams continues, some aspects about the richness, abundance and diversity of ichthyofauna in many of these environments are unknown, which prevents adequate management of fish resources. The goal of this work was to evaluate specific richness and diversity of ichthyofauna in La Viña reservoir (31° 47' S and 65° 01' W, 1,050 ha, 846 m asl, one of the major reservoirs in Córdoba. Fifteen seasonal samplings were made in 1999-2002 using trawl nets and gillnets. A total of 3,242 specimens belonging to 7 species distributed in 5 orders and 5 families were caught. The tetra Astyanax eigenmanniorum (52.9% and the silverside Odontesthes bonariensis (29.3% were the most abundant species; the latter is the main target species for lake fishing and had greatest biomass (63.8%. Average diversity for all samples was H'T = 1.63 (95% confidence interval 1.49 to 1.77. Shannon-Wiener and Simpson diversity indexes values were generally intermediate. Specific richness of La Viña reservoir was moderate compared with other impoundments in central and north Argentina.

  14. Selenium in aquatic biota inhabiting agricultural drains in the Salton Sea Basin, California

    Science.gov (United States)

    Saiki, Michael K.; Martin, Barbara A.; May, Thomas W.

    2012-01-01

    Resource managers are concerned that water conservation practices in irrigated farmlands along the southern border of the Salton Sea, Imperial County, California, could increase selenium concentrations in agricultural drainwater and harm the desert pupfish (Cyprinodon macularius), a federally protected endangered species. As part of a broader attempt to address this concern, we conducted a 3-year investigation to collect baseline information on selenium concentrations in seven agricultural drains inhabited by pupfish. We collected water, sediment, selected aquatic food-chain taxa (particulate organic detritus, filamentous algae, net plankton, and midge [Chironomidae] larvae), and two poeciliid fishes (western mosquitofish Gambusia affinis and sailfin molly Poecilia latipinna) for selenium determinations. The two fish species served as ecological surrogates for pupfish, which we were not permitted to sacrifice. Dissolved selenium ranged from 0.70 to 32.8 μg/L, with selenate as the major constituent. Total selenium concentrations in other environmental matrices varied widely among drains, with one drain (Trifolium 18) exhibiting especially high concentrations in detritus, 5.98–58.0 μg Se/g; midge larvae, 12.7–50.6 μg Se/g; mosquitofish, 13.2–20.2 μg Se/g; and mollies, 12.8–30.4 μg Se/g (all tissue concentrations are based on dry weights). Although toxic thresholds for selenium in fishes from the Salton Sea are still poorly understood, available evidence suggests that ambient concentrations of this element may not be sufficiently elevated to adversely affect reproductive success and survival in selenium-tolerant poeciliids and pupfish.

  15. Development of the hearts of lizards and snakes and perspectives to cardiac evolution.

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    Bjarke Jensen

    Full Text Available Birds and mammals both developed high performance hearts from a heart that must have been reptile-like and the hearts of extant reptiles have an unmatched variability in design. Yet, studies on cardiac development in reptiles are largely old and further studies are much needed as reptiles are starting to become used in molecular studies. We studied the growth of cardiac compartments and changes in morphology principally in the model organism corn snake (Pantherophis guttatus, but also in the genotyped anole (Anolis carolinenis and A. sagrei and the Philippine sailfin lizard (Hydrosaurus pustulatus. Structures and chambers of the formed heart were traced back in development and annotated in interactive 3D pdfs. In the corn snake, we found that the ventricle and atria grow exponentially, whereas the myocardial volumes of the atrioventricular canal and the muscular outflow tract are stable. Ventricular development occurs, as in other amniotes, by an early growth at the outer curvature and later, and in parallel, by incorporation of the muscular outflow tract. With the exception of the late completion of the atrial septum, the adult design of the squamate heart is essentially reached halfway through development. This design strongly resembles the developing hearts of human, mouse and chicken around the time of initial ventricular septation. Subsequent to this stage, and in contrast to the squamates, hearts of endothermic vertebrates completely septate their ventricles, develop an insulating atrioventricular plane, shift and expand their atrioventricular canal toward the right and incorporate the systemic and pulmonary venous myocardium into the atria.

  16. Allele-specific expression at the androgen receptor alpha gene in a hybrid unisexual fish, the Amazon molly (Poecilia formosa.

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    Fangjun Zhu

    Full Text Available The all-female Amazon molly (Poecilia formosa is the result of a hybridization of the Atlantic molly (P. mexicana and the sailfin molly (P. latipinna approximately 120,000 years ago. As a gynogenetic species, P. formosa needs to copulate with heterospecific males including males from one of its bisexual ancestral species. However, the sperm only triggers embryogenesis of the diploid eggs. The genetic information of the sperm donor typically will not contribute to the next generation of P. formosa. Hence, P. formosa possesses generally one allele from each of its ancestral species at any genetic locus. This raises the question whether both ancestral alleles are equally expressed in P. formosa. Allele-specific expression (ASE has been previously assessed in various organisms, e.g., human and fish, and ASE was found to be important in the context of phenotypic variability and disease. In this study, we utilized Real-Time PCR techniques to estimate ASE of the androgen receptor alpha (arα gene in several distinct tissues of Amazon mollies. We found an allelic bias favoring the maternal ancestor (P. mexicana allele in ovarian tissue. This allelic bias was not observed in the gill or the brain tissue. Sequencing of the promoter regions of both alleles revealed an association between an Indel in a known CpG island and differential expression. Future studies may reveal whether our observed cis-regulatory divergence is caused by an ovary-specific trans-regulatory element, preferentially activating the allele of the maternal ancestor.

  17. The behavioural response of adult Petromyzon marinus to damage-released alarm and predator cues

    Science.gov (United States)

    Imre, István; Di Rocco, Richard; Belanger, Cowan; Brown, Grant; Johnson, Nicholas S.

    2014-01-01

    Using semi-natural enclosures, this study investigated (1) whether adult sea lamprey Petromyzon marinus show avoidance of damage-released conspecific cues, damage-released heterospecific cues and predator cues and (2) whether this is a general response to injured heterospecific fishes or a specific response to injured P. marinus. Ten replicate groups of 10 adult P. marinus, separated by sex, were exposed to one of the following nine stimuli: deionized water (control), extracts prepared from adult P. marinus, decayed adult P. marinus (conspecific stimuli), sympatric white sucker Catostomus commersonii, Amazon sailfin catfish Pterygoplichthys pardalis (heterospecific stimuli), 2-phenylethylamine (PEA HCl) solution, northern water snake Nerodia sipedon washing, human saliva (predator cues) and an adult P. marinus extract and human saliva combination (a damage-released conspecific cue and a predator cue). Adult P. marinus showed a significant avoidance response to the adult P. marinus extract as well as to C. commersonii, human saliva, PEA and the adult P. marinus extract and human saliva combination. For mobile P. marinus, the N. sipedon washing induced behaviour consistent with predator inspection. Exposure to the P. pardalis extract did not induce a significant avoidance response during the stimulus release period. Mobile adult female P. marinus showed a stronger avoidance behaviour than mobile adult male P. marinus in response to the adult P. marinus extract and the adult P. marinus extract and human saliva combination. The findings support the continued investigation of natural damage-released alarm cue and predator-based repellents for the behavioural manipulation of P. marinus populations in the Laurentian Great Lakes.

  18. Selenium in aquatic biota inhabiting agricultural drains in the Salton Sea Basin, California.

    Science.gov (United States)

    Saiki, Michael K; Martin, Barbara A; May, Thomas W

    2012-09-01

    Resource managers are concerned that water conservation practices in irrigated farmlands along the southern border of the Salton Sea, Imperial County, California, could increase selenium concentrations in agricultural drainwater and harm the desert pupfish (Cyprinodon macularius), a federally protected endangered species. As part of a broader attempt to address this concern, we conducted a 3-year investigation to collect baseline information on selenium concentrations in seven agricultural drains inhabited by pupfish. We collected water, sediment, selected aquatic food-chain taxa (particulate organic detritus, filamentous algae, net plankton, and midge [Chironomidae] larvae), and two poeciliid fishes (western mosquitofish Gambusia affinis and sailfin molly Poecilia latipinna) for selenium determinations. The two fish species served as ecological surrogates for pupfish, which we were not permitted to sacrifice. Dissolved selenium ranged from 0.70 to 32.8 μg/L, with selenate as the major constituent. Total selenium concentrations in other environmental matrices varied widely among drains, with one drain (Trifolium 18) exhibiting especially high concentrations in detritus, 5.98-58.0 μg Se/g; midge larvae, 12.7-50.6 μg Se/g; mosquitofish, 13.2-20.2 μg Se/g; and mollies, 12.8-30.4 μg Se/g (all tissue concentrations are based on dry weights). Although toxic thresholds for selenium in fishes from the Salton Sea are still poorly understood, available evidence suggests that ambient concentrations of this element may not be sufficiently elevated to adversely affect reproductive success and survival in selenium-tolerant poeciliids and pupfish.

  19. Arsenic, Fluoride and Vanadium in surface water (Chasicó Lake, Argentina

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    Maria laura ePuntoriero

    2014-06-01

    Full Text Available Chasicó Lake is the main water body in the southwest of the Chaco-Pampean plain. It shows some differences from the typical Pampean shallow lakes, such as high salinity and high arsenic and fluoride levels. The aim of this paper is to analyze the trace elements [arsenic (As, fluoride (F- and vanadium (V] present in Chasicó Lake. Surface and groundwater were sampled in dry and wet periods, during 2010 and 2011. Fluoride was determined with a selective electrode. As and V were determined by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES. Significant correlation in surface water was only found for As and F- (r=0.978, p<0.01. The As, F- and V concentration values were higher and more widely dispersed in surface water than in groundwater, as a consequence of evaporation. The fact that these elements do not correlate in surface water may also indicates that groundwater would not be the main source of origin of As, F- and V in surface water. The origin of these trace elements is from volcanic glass from Pampean loess. As, F- and V concentration were higher than in national and international guideline levels for the protection of aquatic biota. Hence, this issue is relevant since the silverside (Odontesthes bonariensis is the most important commercial species in Chasicó Lake. This fish is both consumed locally and exported to other South-American countries through commercial and sport fishing.

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

    Science.gov (United States)

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

    2013-01-01

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

  1. Habituation of adult sea lamprey repeatedly exposed to damage-released alarm and predator cues

    Science.gov (United States)

    Imre, Istvan; Di Rocco, Richard T.; Brown, Grant E.; Johnson, Nicholas

    2016-01-01

    Predation is an unforgiving selective pressure affecting the life history, morphology and behaviour of prey organisms. Selection should favour organisms that have the ability to correctly assess the information content of alarm cues. This study investigated whether adult sea lamprey Petromyzon marinus habituate to conspecific damage-released alarm cues (fresh and decayed sea lamprey extract), a heterospecific damage-released alarm cue (white sucker Catostomus commersoniiextract), predator cues (Northern water snake Nerodia sipedon washing, human saliva and 2-phenylethylamine hydrochloride (PEA HCl)) and a conspecific damage-released alarm cue and predator cue combination (fresh sea lamprey extract and human saliva) after they were pre-exposed 4 times or 8 times, respectively, to a given stimulus the previous night. Consistent with our prediction, adult sea lamprey maintained an avoidance response to conspecific damage-released alarm cues (fresh and decayed sea lamprey extract), a predator cue presented at high relative concentration (PEA HCl) and a conspecific damage-released alarm cue and predator cue combination (fresh sea lamprey extract plus human saliva), irrespective of previous exposure level. As expected, adult sea lamprey habituated to a sympatric heterospecific damage-released alarm cue (white sucker extract) and a predator cue presented at lower relative concentration (human saliva). Adult sea lamprey did not show any avoidance of the Northern water snake washing and the Amazon sailfin catfish extract (heterospecific control). This study suggests that conspecific damage-released alarm cues and PEA HCl present the best options as natural repellents in an integrated management program aimed at controlling the abundance of sea lamprey in the Laurentian Great Lakes.

  2. Benthic and pelagic pathways of methylmercury bioaccumulation in estuarine food webs of the northeast United States.

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    Celia Y Chen

    Full Text Available Methylmercury (MeHg is a contaminant of global concern that bioaccumulates and bioamagnifies in marine food webs. Lower trophic level fauna are important conduits of MeHg from sediment and water to estuarine and coastal fish harvested for human consumption. However, the sources and pathways of MeHg to these coastal fisheries are poorly known particularly the potential for transfer of MeHg from the sediment to biotic compartments. Across a broad gradient of human land impacts, we analyzed MeHg concentrations in food webs at ten estuarine sites in the Northeast US (from the Hackensack Meadowlands, NJ to the Gulf of Maine. MeHg concentrations in water column particulate material, but not in sediments, were predictive of MeHg concentrations in fish (killifish and Atlantic silversides. Moreover, MeHg concentrations were higher in pelagic fauna than in benthic-feeding fauna suggesting that MeHg delivery to the water column from methylation sites from within or outside of the estuary may be an important driver of MeHg bioaccumulation in estuarine pelagic food webs. In contrast, bulk sediment MeHg concentrations were only predictive of concentrations of MeHg in the infaunal worms. Our results across a broad gradient of sites demonstrate that the pathways of MeHg to lower trophic level estuarine organisms are distinctly different between benthic deposit feeders and forage fish. Thus, even in systems with contaminated sediments, transfer of MeHg into estuarine food webs maybe driven more by the efficiency of processes that determine MeHg input and bioavailability in the water column.

  3. Phototoxic potential of undispersed and dispersed fresh and weathered Macondo crude oils to Gulf of Mexico Marine Organisms.

    Science.gov (United States)

    Finch, Bryson E; Marzooghi, Solmaz; Di Toro, Dominic M; Stubblefield, William A

    2017-10-01

    Crude oils contain a mixture of hydrocarbons, including phototoxic polycyclic aromatic hydrocarbons (PAHs) that have the ability to absorb ultraviolet (UV) light. Absorption of UV light by PAHs can substantially increase their toxicity to marine organisms. The objective of the present study was to examine the potential for phototoxicity of fresh and naturally weathered Macondo crude oils alone and in combination with the dispersant Corexit 9500 to mysid shrimp (Americamysis bahia), inland silverside (Menidia beryllina), sheepshead minnow (Cyprinodon variegatus), and Gulf killifish (Fundulus grandis). Acute toxicity tests were conducted using combinations of natural or artificial sunlight and low-energy water-accommodated fractions (WAFs) of fresh and weathered Macondo crude oils collected from the Gulf of Mexico. Studies were also conducted to compare the phototoxicity resulting from natural and artificial sunlight. Fresh Macondo crude oil was more phototoxic than weathered crude oils, both in the presence and in the absence of UV light. Differences in toxicity between fresh and weathered crude oils were likely attributed to lighter-ringed PAHs in fresh crude oils. Phototoxic PAHs were relatively resistant to weathering compared with lighter-ringed PAHs. The addition of Corexit 9500 to crude oil increased toxicity compared with tests with crude oil alone, by increasing phototoxic PAH concentrations in WAFs. Macondo crude oils had the potential to be phototoxic to Gulf of Mexico marine organisms if specific light conditions and PAH concentrations were present during the Deepwater Horizon oil spill. Environ Toxicol Chem 2017;36:2640-2650. © 2017 SETAC. © 2017 SETAC.

  4. Evaluation of water quality threats to the endangered Okaloosa darter (Etheostoma okaloosae) in East Turkey Creek on Eglin Air Force Base.

    Science.gov (United States)

    Weil, R E; Spade, D J; Knoebl, I; Hemming, J M; Tongue, M L; Szabo, N J; Kroll, K J; Tate, W B; Denslow, N D

    2012-04-01

    The threatened Okaloosa darter (Etheostoma okaloosae) is found almost exclusively on the Eglin Air Force Base in the Choctawhatchee Bay watershed of Florida. Portions of this limited habitat are threatened with soil erosion, altered hydrology, and impaired water quality. In the present study, general water quality parameters (i.e., dissolved oxygen, specific conductance, pH, temperature, relative turbidity, and primary productivity) were characterized in East Turkey Creek, which is a body of water potentially impacted by treated wastewater sprayfields, and Long Creek, an adjacent reference stream that does not border the sprayfields. Water quality was assessed during a 30-day exposure using passive samplers for both non-polar and polar effluent parameters. Because the Okaloosa darter was listed as endangered at the time of sampling we chose a closely related species from the same creeks, the sailfin shiner (Pteronotropis hypseleotris) in which to measure metal body burdens. Additionally, fathead minnows (Pimephales promelas) were used for microarray analysis on gonad and liver tissues after 48 h exposures to water collected from the two creeks and brought into the laboratory. Waters from all sites, including reference sites, affected the expression of genes related to various biological processes including transcription and translation, cell cycle control, metabolism, and signaling pathways, suggesting that the sum of anthropogenic compounds in the site waters may cause a generalized stress response in both liver and testis, an effect that could be related to the generally low populations of the Okaloosa darter. Furthermore, effects of site waters on fish gene expression may be related to the impact of human activities other than the wastewater sprayfields, as nearby areas are closed to the public for military testing, training, and administrative activities and due to ordnance contamination. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Diet of the fishing bat Noctilio leporinus (Linnaeus (Mammalia, Chiroptera in a mangrove area of southern Brazil Dieta do morcego-pescador Noctilio leporinus (Linnaeus (Mammalia, Chiroptera em uma área de manguezal do sul do Brasil

    Directory of Open Access Journals (Sweden)

    Marcelo O. Bordignon

    2006-03-01

    Full Text Available From January to December 1999, the diet of Noctilio leporinus (Linnaeus, 1758 was determined in a salt-water ecosystem, by analysing the feces of bats captured in mist nets. Of the 61 samples analyzed, most contained remains of fish (90.2%, followed by insects (70.5% and crustaceous (29.5%. The most frequent fishes species were: silversides Atherinella brasiliensis (Quoy & Gaimard, 1825, anchovies Cetengraulis edentulus (Cuvier, 1829 and scaly sardines Ophisthonema oglinum (Lesueur, 1818. The most frequent insects were moths (Saturniidae and beetles (Cerambycidae, Scarabaeidae and Coccinellidae, as well as two species of bat ectoparasites (Streblidae. Among the crustaceous the shrimp (Palaemonidae and crabs (Gecarcinidae are was present. The consumption of fish, insects and crustaceans was different for the males and females throughout the year.De janeiro a dezembro de 1999, foi estudada a dieta de Noctilio leporinus (Linnaeus, 1758 em um ecossistema de manguezal, através da análise das fezes de morcegos capturados com redes-neblina. Das 61 amostras analisadas, a maioria continha fragmentos de peixes (90.2%, seguido de insetos (70.5% e crustáceos (29,5%. As espécies de peixes mais freqüentes foram: peixe-rei Atherinella brasiliensis (Quoy & Gaimard, 1825, manjuba Cetengraulis edentulus (Cuvier, 1829 e sardinha Ophisthonema oglinum (Lesueur, 1818. Os insetos mais freqüentes foram mariposas (Saturniidae e besouros (Cerambycidae, Scarabaeidae e Coccinellidae, além de duas espécies de ectoparasitas (Streblidae. Entre os crustáceos, houve a presença apenas de camarões (Palaemonidae e siris (Gecarcinidae. O consumo de peixes, insetos e crustáceos foi diferente para machos e fêmeas ao longo do ano.

  6. Agricultural wetlands as potential hotspots for mercury bioaccumulation: Experimental evidence using caged fish

    Science.gov (United States)

    Ackerman, Joshua T.; Eagles-Smith, Collin A.

    2010-01-01

    Wetlands provide numerous ecosystem services, but also can be sources of methylmercury (MeHg) production and export. Rice agricultural wetlands in particular may be important sites for MeHg bioaccumulation due to their worldwide ubiquity, periodic flooding schedules, and high use by wildlife. We assessed MeHg bioaccumulation within agricultural and perennial wetlands common to California's Central Valley during summer, when the majority of wetland habitats are shallowly flooded rice fields. We introduced caged western mosquitofish (Gambusia affinis) within white rice (Oryza sativa), wild rice (Zizania palustris), and permanent wetlands at water inlets, centers, and outlets. Total mercury (THg) concentrations and body burdens in caged mosquitofish increased rapidly, exceeding baseline values at introduction by 135% to 1197% and 29% to 1566% among sites, respectively, after only 60 days. Mercury bioaccumulation in caged mosquitofish was greater in rice fields than in permanent wetlands, with THg concentrations at wetland outlets increasing by 12.1, 5.8, and 2.9 times over initial concentrations in white rice, wild rice, and permanent wetlands, respectively. In fact, mosquitofish caged at white rice outlets accumulated 721 ng Hg/fish in just 60 days. Mercury in wild mosquito fish and Mississippi silversides (Menidia audens) concurrently sampled at wetland outlets also were greater in white rice and wild rice than permanent wetlands. Within wetlands, THg concentrations and body burdens of both caged and wild fish increased from water inlets to outlets in white rice fields, and tended to not vary among sites in permanent wetlands. Fish THg concentrations in agricultural wetlands were high, exceeding 0.2 ??g/g ww in 82% of caged fish and 59% of wild fish. Our results indicate that shallowly flooded rice fields are potential hotspots for MeHg bioaccumulation and, due to their global prevalence, suggest that agricultural wetlands may be important contributors to Me

  7. Genetic parameters of Visual Image Analysis primal cut carcass traits of commercial prime beef slaughter animals.

    Science.gov (United States)

    Moore, K L; Mrode, R; Coffey, M P

    2017-10-01

    Visual Image analysis (VIA) of carcass traits provides the opportunity to estimate carcass primal cut yields on large numbers of slaughter animals. This allows carcases to be better differentiated and farmers to be paid based on the primal cut yields. It also creates more accurate genetic selection due to high volumes of data which enables breeders to breed cattle that better meet the abattoir specifications and market requirements. In order to implement genetic evaluations for VIA primal cut yields, genetic parameters must first be estimated and that was the aim of this study. Slaughter records from the UK prime slaughter population for VIA carcass traits was available from two processing plants. After edits, there were 17 765 VIA carcass records for six primal cut traits, carcass weight as well as the EUROP conformation and fat class grades. Heritability estimates after traits were adjusted for age ranged from 0.32 (0.03) for EUROP fat to 0.46 (0.03) for VIA Topside primal cut yield. Adjusting the VIA primal cut yields for carcass weight reduced the heritability estimates, with estimates of primal cut yields ranging from 0.23 (0.03) for Fillet to 0.29 (0.03) for Knuckle. Genetic correlations between VIA primal cut yields adjusted for carcass weight were very strong, ranging from 0.40 (0.06) between Fillet and Striploin to 0.92 (0.02) between Topside and Silverside. EUROP conformation was also positively correlated with the VIA primal cuts with genetic correlation estimates ranging from 0.59 to 0.84, whereas EUROP fat was estimated to have moderate negative correlations with primal cut yields, estimates ranged from -0.11 to -0.46. Based on these genetic parameter estimates, genetic evaluation of VIA primal cut yields can be undertaken to allow the UK beef industry to select carcases that better meet abattoir specification and market requirements.

  8. From 'omics to otoliths: responses of an estuarine fish to endocrine disrupting compounds across biological scales.

    Science.gov (United States)

    Brander, Susanne M; Connon, Richard E; He, Guochun; Hobbs, James A; Smalling, Kelly L; Teh, Swee J; White, J Wilson; Werner, Inge; Denison, Michael S; Cherr, Gary N

    2013-01-01

    Endocrine disrupting chemicals (EDCs) cause physiological abnormalities and population decline in fishes. However, few studies have linked environmental EDC exposures with responses at multiple tiers of the biological hierarchy, including population-level effects. To this end, we undertook a four-tiered investigation in the impacted San Francisco Bay estuary with the Mississippi silverside (Menidia audens), a small pelagic fish. This approach demonstrated links between different EDC sources and fish responses at different levels of biological organization. First we determined that water from a study site primarily impacted by ranch run-off had only estrogenic activity in vitro, while water sampled from a site receiving a combination of urban, limited ranch run-off, and treated wastewater effluent had both estrogenic and androgenic activity. Secondly, at the molecular level we found that fish had higher mRNA levels for estrogen-responsive genes at the site where only estrogenic activity was detected but relatively lower expression levels where both estrogenic and androgenic EDCs were detected. Thirdly, at the organism level, males at the site exposed to both estrogens and androgens had significantly lower mean gonadal somatic indices, significantly higher incidence of severe testicular necrosis and altered somatic growth relative to the site where only estrogens were detected. Finally, at the population level, the sex ratio was significantly skewed towards males at the site with measured androgenic and estrogenic activity. Our results suggest that mixtures of androgenic and estrogenic EDCs have antagonistic and potentially additive effects depending on the biological scale being assessed, and that mixtures containing androgens and estrogens may produce unexpected effects. In summary, evaluating EDC response at multiple tiers is necessary to determine the source of disruption (lowest scale, i.e. cell line) and what the ecological impact will be (largest scale, i

  9. Patterns in the Use of a Restored California Floodplain by Native and Alien Fishes

    Directory of Open Access Journals (Sweden)

    Peter B Moyle

    2007-07-01

    Full Text Available Fishes were sampled on the restored floodplain of the Cosumnes River in Central California in order to determine patterns of floodplain use. The floodplain was sampled for seven years (1998-2002, 2004-2005 during the winter-spring flooding season. The fishes fell into five groups: (1 floodplain spawners, (2 river spawners, (3 floodplain foragers, (4 floodplain pond fishes, and (5 inadvertent users. Eight of the 18 abundant species were natives, while the rest were aliens. There was a consistent pattern of floodplain use, modified by timing and extent of flooding. The first fishes to appear were floodplain foragers, inadvertent users, and juvenile Chinook salmon (river spawners. Next were floodplain spawners, principally Sacramento splittail and common carp. At the end of the season, in ponds of residual water, non-native annual fishes, mainly inland silverside and western mosquitofish, became abundant. Adult spawners left when inflow decreased; their juveniles persisted as long as flood pulses kept water levels up and temperatures low. Juvenile splittail and carp quickly grew large enough to dominate floodplain fish samples, along with smaller numbers of juvenile Sacramento sucker and pikeminnow (river spawners. Such juveniles left the Relatively few fishes that used the floodplain for spawning or rearing became stranded, except late season alien fishes. Most alien fishes had resident populations in adjacent river, sloughs, and ditches and were not dependent on the floodplain for persistence. This indicates that Central Valley floodplains managed to favor native fishes should have the following char- acteristics: (1 extensive early season flooding, (2 complete drainage by the end of the flooding season, (3 few areas with permanent water, (4 a mosaic of physical habitats, (5 regular annual flooding but with high variability in flood regime.

  10. Ontogenetic patterns in bluefish (Pomatomus saltatrix) feeding ecology and the effect on mercury biomagnification.

    Science.gov (United States)

    Szczebak, Joseph T; Taylor, David L

    2011-06-01

    In this study, bluefish (Pomatomus saltatrix; age 0-7, n = 632) and their prey (forage fish, macroinvertebrates, zooplankton; n = 2,005) were collected from the Narragansett Bay estuary (RI, USA), and total Hg concentration was measured in white muscle and whole-body tissues, respectively. Bluefish Hg concentrations were analyzed relative to fish length, prey Hg content, and ontogenetic shifts in habitat use and foraging ecology, the latter assessed using stomach content analysis (n = 711) and stable nitrogen (δ(15)N) and carbon (δ(13)C) isotope measurements (n = 360). Diet and δ(13)C analysis showed that age 0 bluefish consumed both benthic and pelagic prey (silversides, sand shrimp, planktonic crustaceans; δ(13)C = - 16.52‰), whereas age 1 + bluefish fed almost exclusively on pelagic forage fish (Atlantic menhaden, herring; δ(13)C = - 17.33‰). Bluefish total Hg concentrations were significantly correlated with length (mean Hg = 0.041 and 0.254 ppm wet wt for age 0 and age 1 + bluefish, respectively). Furthermore, Hg biomagnification rates were maximal during bluefish early life stages and decelerated over time, resulting in relatively high Hg concentrations in age 0 fish. Rapid Hg accumulation in age 0 bluefish is attributed to these individuals occupying a comparable trophic level to age 1 + bluefish (δ(15)N = 15.58 and 16.09‰; trophic level = 3.55 and 3.71 for age 0 and age 1 + bluefish, respectively), as well as juveniles having greater standardized consumption rates of Hg-contaminated prey. Finally, bluefish larger than 30 cm total length consistently had Hg levels above the U.S. Environmental Protection Agency criterion of 0.3 ppm. As such, frequent consumption of bluefish could pose a human health risk, and preferentially consuming smaller bluefish may be an inadequate strategy for minimizing human dietary exposure to Hg. Copyright © 2011 SETAC.

  11. Assessing the link between coastal urbanization and the quality of nekton habitat in mangrove tidal tributaries

    Science.gov (United States)

    Krebs, Justin M.; Bell, Susan S.; McIvor, Carole C.

    2014-01-01

    To assess the potential influence of coastal development on habitat quality for estuarine nekton, we characterized body condition and reproduction for common nekton from tidal tributaries classified as undeveloped, industrial, urban or man-made (i.e., mosquito-control ditches). We then evaluated these metrics of nekton performance, along with several abundance-based metrics and community structure from a companion paper (Krebs et al. 2013) to determine which metrics best reflected variation in land-use and in-stream habitat among tributaries. Body condition was not significantly different among undeveloped, industrial, and man-made tidal tributaries for six of nine taxa; however, three of those taxa were in significantly better condition in urban compared to undeveloped tributaries. Palaemonetes shrimp were the only taxon in significantly poorer condition in urban tributaries. For Poecilia latipinna, there was no difference in body condition (length–weight) between undeveloped and urban tributaries, but energetic condition was significantly better in urban tributaries. Reproductive output was reduced for both P. latipinna (i.e., fecundity) and grass shrimp (i.e., very low densities, few ovigerous females) in urban tributaries; however a tradeoff between fecundity and offspring size confounded meaningful interpretation of reproduction among land-use classes for P. latipinna. Reproductive allotment by P. latipinna did not differ significantly among land-use classes. Canonical correspondence analysis differentiated urban and non-urban tributaries based on greater impervious surface, less natural mangrove shoreline, higher frequency of hypoxia and lower, more variable salinities in urban tributaries. These characteristics explained 36 % of the variation in nekton performance, including high densities of poeciliid fishes, greater energetic condition of sailfin mollies, and low densities of several common nekton and economically important taxa from urban tributaries

  12. Analysis and Evaluation of Nutrients and Fatty Acids of Mongolian Horsemeat%蒙古马肉常规营养素和脂肪酸分析评价

    Institute of Scientific and Technical Information of China (English)

    刘莉敏; 郭军; 木其尔; 张晶; 张鑫; 张晓儒

    2017-01-01

    以蒙古马后腿、肋部、里脊和皮下脂肪为研究对象,兼顾内蒙地区驴、牛、绵羊和双峰驼肉,共采集130份样品,系统测定其常规营养素和脂肪酸,并进行物种、部位、产地和季节等分类比较.蒙古马后腿、肋部和里脊肉三个部位常规营养素均值(均值±SD):水分、脂肪、蛋白质、灰分分别为75.65±2.29、2.22±1.43、20.34±1.30、1.23±0.23g/100g;水分和蛋白质显著高于牛、绵羊和驼肉,脂肪显著低.蒙古马肉饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)和多不饱和脂肪酸(PUFA)(均值±SD)分别为42.18±5.49、28.28±6.81、26.83±7.58g/100脂肪,其中PUFA显著高于其他物种,MUFA显著低.蒙古马肉α-亚麻酸(α-C18∶3n3)、亚油酸(C18∶2n6c)和软脂酸(C16∶0)显著高于牛羊驼肉,硬脂酸(C18∶0)、棕榈烯酸(C16∶1)和油酸(C18∶1n9c)显著低于三者.蒙古马肉皮下脂肪中α-C18∶3n3显著高于其他部位,C18∶2n6c显著低;青草季α-C18∶3n3高于干草季,C18∶1n9c和C16∶1与其相反,差异均极显著;呼伦贝尔蒙古马肉α-C18∶3n3、C18∶2n6c和C18∶0均显著高于达茂旗马肉.蒙古马肉具有高蛋白、低脂肪的特点,且脂肪营养价值优于牛羊驼等反刍类动物.%A total of 130 Mongolian horse,donkey,cattle,sheep and bactrian camel meat samples were collected,the body cuts included silverside,rib cut,loin and subcutaneous fat,and routine nutrients and fatty acids were determined.The nutrients profiles were compared systematically according to classifications/categories such as species,body parts/cuts,geographical origin and between hay and pasture/grazing season.Results showed the routine nutrients,total means of silverside,rib and loin of Mongolian horsemeat were moisture 75.65 ±2.29,fat 2.22 ± 1.43,protein 20.34 ± 1.30 and ash 1.23 ±0.23 respectively ((x) ±SD,g/100g).The moisture and protein significantly higher than those of the three ruminants,while fat was

  13. Year 3 Summary Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin

    Science.gov (United States)

    Saiki, Michael K.; Martin, Barbara A.; May, Thomas W.

    2008-01-01

    This report summarizes findings from the third year of a 4-year-long field investigation to document selected baseline environmental conditions in 29 agricultural drains and ponds operated by the Imperial Irrigation District along the southern border of the Salton Sea. Routine water quality and fish species were measured at roughly quarterly intervals from April 2007 to January 2008. The water quality measurements included total suspended solids and total (particulate plus dissolved) selenium. In addition, during April and October 2007, water samples were collected from seven intensively monitored drains for measurement of particulate and dissolved selenium, including inorganic and organic fractions. In addition, sediment, aquatic food chain matrices (particulate organic detritus, filamentous algae, net plankton, and midge [chironomid] larvae), and two fish species (western mosquitofish, Gambusia affinis; and sailfin molly, Poecilia latipinna) were sampled from the seven drains for measurement of total selenium concentrations. The mosquitofish and mollies were intended to serve as surrogates for desert pupfish (Cyprinodon macularius), an endangered species that we were not permitted to take for selenium determinations. Water quality values were typical of surface waters in a hot desert climate. A few drains exhibited brackish, near anoxic conditions especially during the summer and fall when water temperatures occasionally exceeded 30 degrees C. In general, total selenium concentrations in water varied directly with conductivity and inversely with pH. Although desert pupfish were found in several drains, sometimes in relatively high numbers, the fish faunas of most drains and ponds were dominated by nonnative species, especially red shiner (Cyprinella lutrensis), mosquitofish, and mollies. Dissolved selenium in water samples from the seven intensively monitored drains ranged from 0.700 to 24.1 ug/L, with selenate as the major constituent in all samples. Selenium

  14. Macroinvertebrate Prey Availability and Fish Diet Selectivity in Relation to Environmental Variables in Natural and Restoring North San Francisco Bay Tidal Marsh Channels

    Directory of Open Access Journals (Sweden)

    Emily R. Howe

    2014-03-01

    Full Text Available Tidal marsh wetlands provide important foraging habitat for a variety of estuarine fishes. Prey organisms include benthic–epibenthic macroinvertebrates, neustonic arthropods, and zooplankton. Little is known about the abundance and distribution of interior marsh macroinvertebrate communities in the San Francisco Estuary (estuary. We describe seasonal, regional, and site variation in the composition and abundance of neuston and benthic–epibenthic macroinvertebrates that inhabit tidal marsh channels, and relate these patterns to environmental conditions. We also describe spatial and temporal variation in diets of marsh-associated inland silverside, yellowfin goby, and western mosquitofish. Fish and invertebrates were sampled quarterly from October 2003 to June 2005 at six marsh sites located in three river systems of the northern estuary: Petaluma River, Napa River, and  the west Delta. Benthic/epibenthic macroinvertebrates and neuston responded to environmental variables related to seasonal changes (i.e., temperature, salinity, as well as those related to marsh structure (i.e., vegetation, channel edge. The greatest variation in abundance occurred seasonally for neuston and spatially for benthic–epibenthic organisms, suggesting that each community responds to different environmental drivers. Benthic/epibenthic invertebrate abundance and diversity was lowest in the west Delta, and increased with increasing salinity. Insect abundance increased during the spring and summer, while Collembolan (springtail abundance increased during the winter. Benthic/epibenthic macroinvertebrates dominated fish diets, supplemented by insects, with zooplankton playing a minor role. Diet compositions of the three fish species overlapped considerably, with strong selection indicated for epibenthic crustaceans—a surprising result given the typical classification of Menidia beryllina as a planktivore, Acanthogobius flavimanus as a benthic predator, and Gambusia

  15. Habitat and hydrology: assessing biological resources of the Suwannee River Estuarine System

    Science.gov (United States)

    Raabe, Ellen A.; Edwards, Randy E.; McIvor, Carole C.; Grubbs, Jack W.; Dennis, George D.

    2007-01-01

    The U.S. Geological Survey conducted a pilot integrated-science study during 2002 and 2003 to map, describe, and evaluate benthic and emergent habitats in the Suwannee River Estuary on the Gulf Coast of Florida. Categories of aquatic, emergent, and terrestrial habitats were determined from hyperspectral imagery and integrated with hydrologic data to identify estuarine fish habitats. Maps of intertidal and benthic habitat were derived from 12-band, 4-m resolution hyperspectral imagery acquired in September 2002. Hydrologic data were collected from tidal creeks during the winter of 2002-03 and the summer-fall of 2003. Fish were sampled from tidal creeks during March 2003 using rivulet nets, throw traps, and seine nets. Habitat characteristics, hydrologic data, and fish assemblages were compared for tidal creeks north and south of the Suwannee River. Tidal creeks north of the river had more shoreline edge and shallow habitat than creeks to the south. Tidal creeks south of the river were generally of lower salinity (fresher) and supported more freshwater marsh and submerged aquatic vegetation. The southern creeks tended to be deeper but less sinuous than the northern creeks. Water quality and inundation were evaluated with hydrologic monitoring in the creeks. In-situ gauges, recording pressure and temperature, documented a net discharge of brackish to saline groundwater into the tidal creeks with pronounced flow during low tide. Groundwater flow into the creeks was most prominent north of the river. Combined fish-sampling results showed an overall greater abundance of organisms and greater species richness in the southern creeks, nominally attributed a greater range in water quality. Fish samples were dominated by juvenile spot, grass shrimp, bay anchovy, and silverside. The short time frame for hydrologic monitoring and the one-time fish-sampling effort were insufficient for forming definitive conclusions. However, the combination of hyperspectral imagery and

  16. Transcriptomic changes underlie altered egg protein production and reduced fecundity in an estuarine model fish exposed to bifenthrin.

    Science.gov (United States)

    Brander, Susanne M; Jeffries, Ken M; Cole, Bryan J; DeCourten, Bethany M; White, J Wilson; Hasenbein, Simone; Fangue, Nann A; Connon, Richard E

    2016-05-01

    Pyrethroid pesticides are a class of insecticides found to have endocrine disrupting properties in vertebrates such as fishes and in human cell lines. Endocrine disrupting chemicals (EDCs) are environmental contaminants that mimic or alter the process of hormone signaling. In particular, EDCs that alter estrogen and androgen signaling pathways are of major concern for fishes because these EDCs may alter reproductive physiology, behavior, and ultimately sex ratio. Bifenthrin, a pyrethroid with escalating usage, is confirmed to disrupt estrogen signaling in several species of fish, including Menidia beryllina (inland silverside), an Atherinid recently established as a euryhaline model. Our main objective was to broadly assess the molecular and physiological responses of M. beryllina to the ng/L concentrations of bifenthrin typically found in the environment, with a focus on endocrine-related effects, and to discern links between different tiers of the biological hierarchy. As such, we evaluated the response of juvenile Menidia to bifenthrin using a Menidia-specific microarray, quantitative real-time polymerase chain reaction (qPCR) on specific endocrine-related genes of interest, and a Menidia-specific ELISA to the egg-coat protein choriogenin, to evaluate a multitude of molecular-level responses that would inform mechanisms of toxicity and any underlying causes of change at higher biological levels of organization. The sublethal nominal concentrations tested (0.5, 5 and 50ng/L) were chosen to represent the range of concentrations observed in the environment and to provide coverage of a variety of potential responses. We then employed a 21-day reproductive assay to evaluate reproductive responses to bifenthrin (at 0.5ng/L) in a separate group of adult M. beryllina. The microarray analysis indicated that bifenthrin influences a diverse suite of molecular pathways, from baseline metabolic processes to carcinogenesis. A more targeted examination of gene expression via q

  17. Habitat selection and quality for multiple cohorts of young-of-the-year bluefish ( Pomatomus saltatrix): Comparisons between estuarine and ocean beaches in southern New Jersey

    Science.gov (United States)

    Taylor, David L.; Nichols, Ryan S.; Able, Kenneth W.

    2007-07-01

    In this study, seasonal and annual variability in the use of estuarine and ocean beaches by young-of-the-year bluefish, Pomatomus saltatrix, was evaluated by indices of abundance in coastal areas of southern New Jersey (1998-2000). Biological and physical factors measured at specific sites were correlated with bluefish abundance to determine the mechanisms underlying habitat selection. In addition, integrative and discrete indicators of bluefish growth were used to examine spatio-temporal dynamics in habitat quality and its effect on habitat selection by multiple cohorts of bluefish. Intra-annual recruitment to coastal areas of southern New Jersey was episodic, and resulted from the ingress of spring-spawned bluefish (hatch-date ˜April) to estuarine beaches in late May to early June, followed by the recruitment of summer-spawned fish (hatch-date ˜early July) to ocean beaches from July to October. Bluefish utilized estuarine and ocean beaches in a facultative manner that was responsive to dynamics in prey composition and temperature conditions. The recruitment and residency of bluefish in the estuary (1998-1999) and ocean beaches (1998), for example, was coincidental with the presence of the Atlantic silverside Menidia menidia and bay anchovy Anchoa mitchilli, the principal prey species for bluefish occupying these respective habitat-types. Bluefish abundance in the estuary (2000) and ocean beaches (1999-2000) was also correlated with water temperature, with the greatest catches of juveniles coinciding with their optimal growth temperature (24 °C). Bluefish growth, estimated as the slope of age-length relationships and daily specific growth rates, equaled 1.27-2.63 mm fork length (FL) d -1 and 3.8-8.7% body length increase d -1, respectively. The growth of sagittal otoliths was also used as a proxy for changes in bluefish size during and shortly before their time of capture. Accordingly, otolith growth rates of summer-spawned bluefish were greater at ocean

  18. Desarrollo de la sagitta en juveniles y adultos de Odontesthes argentinensis (Valenciennes, 1835 y O. bonariensis (Valenciennes, 1835 de la provincia de Buenos Aires, Argentina (Teleostei: Atheriniformes Development of the sagitta in young and adults of Odontesthes argentinensis (Valenciennes, 1835 and Odontesthes bonariensis (Valenciennes, 1835 from Buenos Aires province, Argentina (Teleostei: Atheriniformes

    Directory of Open Access Journals (Sweden)

    ANDREA D TOMBARI

    2005-12-01

    Full Text Available Se describió el desarrollo del otolito Sagitta de juveniles y adultos de Odontesthes argentinensis procedentes de Punta Rasa (36°22' S y Miramar (38°16' S y de Odontesthes bonariensis de la Laguna de Chascomús (35° 36' S. Se estudió, la morfología de las sagittae de ambas especies, analizando cuatro grupos morfológicos para O. argentinensis (I: 75-120 mm, II: 130-220 mm, III: 230-270 y IV: 280-320 mm y tres grupos morfológicos para O. bonariensis (I: 80-120 mm, II: 130-220 y III: 230-320 mm. Las características morfológicas comunes a la sagitta, de ambas especies, en los grupos estudiados son: presencia de sulcus, depresión areal dorsal en la cara medial, cara lateral con estrías y la presencia de un punto culminante en el borde dorsal. En la sagitta de O. argentinensis, la depresión areal dorsal se inicia ligada a la cauda, característica que permitió distinguir claramente entre otolitos de juveniles de ambas especies. A partir del estado adulto, la depresión areal dorsal se halla separada de la cauda en las dos especies y el análisis estadístico evidenció un crecimiento discontinuo. Se hallaron diferencias morfológicas entre pares de sagitta de un mismo individuo en cuanto a la forma del ostium, presencia de cisura, rostro y punto culminante, aunque no se halló significancia morfométricaThe development of the otolith sagitta was described in young and adults of two silverside species. Odontesthes argentinensis was collected from Punta Rasa (36°22' S and Miramar (38°16' S and, Odontesthes bonariensis collected from Laguna de Chascomús (35°36' S. Sagitta morphology was studied in both species, analyzing four morphological groups of O. argentinensis (I: 75-120 mm, II: 130-220 mm, III: 230-270 mm and IV: 280-320 mm and three morphological groups of O. bonariensis (I: 80-120 mm, II: 130-220 mm and III: 230-320 mm. The morphological features of the sagitta shared by both species are: sulcus present, dorsal areal depression

  19. Efecto de las condiciones de crecimiento y composición del medio de cultivo sobre la producción de bacteriocina de Enterococcus mundtii Tw56

    Directory of Open Access Journals (Sweden)

    Marisol Vallejo

    2014-07-01

    intestinal content of silverside (Odontesthes sp.. The aim of the present work was to determine physicochemical factors and culture medium composition for higher yield of viable cells and bacteriocin production. No changes were observed in the antimicrobial production when glucose was replaced by fructose or maltose in the MRS medium formulation. On the other hand, highest bacteriocin activity was obtained when meat extract was used as a sole nitrogen source. While the maximun biomass was achieved at35 ºC, the optimal temperatures for bacteriocin production were observed at 25 and30 ºC. The optimal initial pH for cell growth and bioactivity was 6.5, both parameters dropped when the experience started at pH 6.0 or 5.5. Biomass formation and bacteriocin production decreased in the presence of sodium chloride. The strain started producing the bacteriocin at the late exponential phase. The activity increased as a function of the cell mass and reached the maximun at the end of exponential phase (12 h. A decrease of antimicrobial activity was observed in the stationary phase (16 h, possibly due to degradation by proteolitic enzimes.  Key words: Enterococcus mundtii Tw56, bacteriocin, physicochemical factors, culture medium.  Recibido: noviembre 18 de 2013 Aprobado: septiembre 18 de 2014

  20. РЕКОМЕНДАЦИИ ЕВРОПЕЙСКОГО ОБЩЕСТВА КАРДИОЛОГОВ ПО ЛЕЧЕНИЮ СЕРДЕЧНО-СОСУДИСТЫХ ЗАБОЛЕВАНИЙ У БЕРЕМЕННЫХ

    Directory of Open Access Journals (Sweden)

    2012-01-01

    Full Text Available Члены комитета по практическим рекомендациям: J.J. Bax (председатель, Нидерланды, A. Auricchio (Швейцария, H. Baumgartner (Германия, C. Ceconi (Италия, V. Dean (Франция, C. Deaton (Великобритания, R. Fagard (Бельгия, C. Funck-Brentano (Франция, D. Has-dai (Израиль, A. Hoes (Нидерланды, J. Knuuti (Финляндия, P . Kolh (Бельгия, T. McDonagh (Великобритания, C. Moulin (Франция, D. Poldermans (Нидерланды, B.A. Popescu (Румыния, Z. Reiner (Хорватия, U. Sechtem (Германия, P .A. Sirnes (Норвегия, A. Torbicki (Польша, A. Vahanian (Франция, S. Windecker (Швейцария Рецензенты: H. Baumgartner (координатор, Германия, C. Deaton (координатор, Великобритания, C. Aguiar (Португалия, N. Al-Attar (Франция, A.A. Garcia (Испания, A. Antoniou (Греция, I. Coman (Румыния, U. Elkayam (США, M.A. Gomez-Sanchez (Испания, N. Gotcheva (Болгария, D. Hilfiker-Kleiner (Германия, R.G. Kiss (Венгрия, A. Kitsiou (Греция, K.T.S. Konings (Нидерланды, G.Y.H. Lip (Великобритания, A. Manolis (Греция, A. Mebaaza (Франция, I. Mintale (Латвия, M-C. Morice (Франция, B.J. Mulder (Нидерланды, A. Pasquet (Бельгия, S. Price (Великобритания, S.G. Priori (Италия, M.J. Salvador (Испания, A. Shotan (Израиль, C.K. Silversides (Канада, S.O. Skouby† (Дания, J-I. Stein¤ (Австрия, P . Tornos (Испания, N. Vejlstrup (Дания, F . Walker (Великобритания, C. Warnes (США

  1. La pesca artesanal en la Cuenca del Plata (Argentina y sus implicancias en la conservación de la biodiversidad Artisanal fish at del Plata basin (Argentina and its implications for the biodiversity conservation

    Directory of Open Access Journals (Sweden)

    Juan Miguel Iwaszkiw

    2011-06-01

    de la pesquería sobre conservación de la biodiversidad de peces de la cuenca.The aim of this contribution is to consider different issues derived from fish captures from artisanal-commercial fisheries in the Paraná Basin in Argentina. We identify certain impacts related to fishing practices on the involved natural populations and its compromises in ichtiofaunal biodiversity conservation. We consider 17 years of information based on data of fisheries exports for different inland species between 1994-2010. These data includes valuable commercial big sized native fishes like sábalo (Prochilodus lineatus, boga (Leporinus obtusidens, tararira (Hoplias malabaricus, surubí (Pseudoplatystoma spp., dorado (Salminus brasiliensis and patí (Luciopimelodus pati, together with several catfish species and minor species as silversides. Freshwater fish exports show a major rise resulting in 331517 ton for these years. The target species is sábalo (88.77 %, other accompanying species are tararira (4.16 %, boga (3.7 % and Patí (1.35 % whereas the remainig catches belong to other species. There is a strong rise in the catches of these other species in certain years while there is not a clear legislation for these fish species that allow implementing a proper fishery management along the basin. The importing countries are Brazil, Colombia, Bolivia and Nigeria among others. Since 2003 Colombia buy an average of 50% of inland fisheries exports from Argentina. The analysis historical data (1994-2010 reveals the need to implement measures to control and management of fisheries and its effects on fish biodiversity conservation in the basin.

  2. The genus Basilichthys (Teleostei: Atherinopsidae revisited along its Chilean distribution range (21° to 40° S using variation in morphologyand mtDNA El género Basilichthys (Teleostei: Atherinopsidae analizado a lo largo de su distribución en Chile (21° a 40° S, utilizando rasgos morfológicos y variabilidad del ADN mitocondrial

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    DAVID VÉLIZ

    2012-03-01

    Full Text Available There is still doubt as to the number of species of the freshwater Chilean ichthyofauna, 64 % of which have conservation problems. One of the groups is that of the silversides of the genus Basilichthys. Three morphological species of this genus have been described in Chile with disjoint distributions: Basilichthys semotilus, B. microlepidotus and B. australis; the latter two overlap in distribution only in the Aconcagua River and are not easily distinguishable by morphological and meristic characters. In order to evaluate the efficacy of identification of these species by molecular techniques, we analyzed the sequence of 9 % of the mitochondrial DNA (Control Region and COI of individuals from the Loa River (21°41' S to the Valdivia River (39°50' S, adding meristic features for B. microlepidotus and B. australis in order to study population variation to clarify the taxonomy of the native species of the genus. The phylogenetic analysis showed that the individuals of Basilichthys semotilus form an haplogroup separated from the other species of the genus; however, B. australis and B. microlepidotus form a monophyletic group that shares the most common haplotypes. An analysis of meristic information showed no statistically significant differences in the number of lateral line scales or number of rays in the fins between B. microlepidotus and B. australis. These results do not support the current classification for the latter two species; there appears to be one group in the extreme north of the country (Basilichthys semotilus and a second group in central Chile which should be called B. microlepidotus. This information will be useful to review the conservation status of the Chilean fauna.Si bien aún existen dudas sobre el número de especies descritas en el país, se reconoce que el 64 % de la ictiofauna dulceacuícola chilena se encuentra en alguna categoría de peligro de conservación. Uno de los grupos categorizados como vulnerable y en

  3. Distribuição, dominância e estrutura de tamanhos da assembleia de peixes da lagoa Mangueira, sul do Brasil Distribution, dominance and sizes structure of the fish assemblage in the Mangueira lake, southern Brazil

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    Luiz G. S Artioli

    2009-12-01

    écies entre as porções norte e sul da lagoa. As 52 espécies registradas neste estudo representam uma alta riqueza de peixes na lagoa Mangueira, sobretudo quando comparada a outras lagoas costeiras do RS. Padrões diferenciados de composição e abundância de espécies parecem refletir características distintas dos habitats litorâneos amostrados.This study presents the composition of species, the distribution and dominance patterns, and the structure of sizes of the assemblage of fish in distinct habitats (littoral, deeper and near shore limnetic zone of the Mangueira lake, in the southern Brazil. Samples were taken in the north, south and central regions of the lake from 2001 to 2007 using a multi-gear approach (gillnet, cast net, beach seine, dip net and bottom trawling. A total of 52 species were identified, 46 in the littoral zone, 33 in the near shore limnetic zone and 26 in the deep zone, distributed in 17 families, of the which, Characidae, Cichlidae, Loricariidae, and Atherinopsidae were the most diverse. The dominant species summed up 91.1 %, 92.9 % and 82.7 % of the all individuals caught in the littoral, deeper and limnetic zone, respectively. The littoral zone was comprised of small fishes, nearly 70 % between 25 and 50 TL mm. The dominance patterns showed that, in this zone, 19,5 % of the species were dominant, although four of those also prevailed in the other zones. In the deep zone, 7,6% of the captured species were dominant, with similar sizes to the littoral zone. For the other species, the sizes resemble to the near shore limnetic zone. The near shore limnetic zone was comprised of larger fishes, the major part between 150 and 200 TL mm, such as the great characins, the toothless characin and the silverside fishes. A larger difference was observed in the composition of species between the littoral and limnetic zones, with the species Jenynsia multidentata, Bryconamericus iheringii, Hyphessobrycon luetkenii and Gymnogeophagus gymnogenys dominating

  4. Spatially explicit habitat models for 28 fishes from the Upper Mississippi River System (AHAG 2.0)

    Science.gov (United States)

    Ickes, Brian S.; Sauer, J.S.; Richards, N.; Bowler, M.; Schlifer, B.

    2014-01-01

    perhaps why). Our goal was to develop regionalized models, and to assess and describe circumstances when a good fit was not possible. Seven fish species composed the Lentic guild. Good fits were achieved for six Upper Reach models. In the Lower Reach, no model produced good fits for the Lentic guild. This was due to (1) lentic species being much less prominent in the Lower Reach study areas, and (2) those that do express greater prominence principally do so only in the La Grange reach of the Illinois River. Thus, developing Lower Reach models for Lentic species will require parsing La Grange from the other two Lower Reach study areas and fitting separate models. We did not do that as part of this study, but it could be done at a later time. Nine species comprised the Lotic guild. Good fits were achieved for seven Upper Reach models and six Lower Reach models. Four species had good fits for both regions (flathead catfish, blue sucker, sauger, and shorthead redhorse). Three species showed zoogeographic zonation, with a good model fit in one of the regions, but not in the region in which they were absent or rarely occurred (blue catfish, rock bass, and skipjack herring). Twelve species comprised the Generalist guild. Good fits were achieved for five Upper Reach models and eight Lower Reach models. Six species had good fits for both regions (brook silverside, emerald shiner, freshwater drum, logperch, longnose gar, and white bass). Two species showed zoogeographic zonation, with a good model fit in one of the regions, but not in the region in which they were absent or rarely occurred (red shiner and blackstripe topminnow). Poorly fit models were almost always due to the diagnostic variable “field station,” a surrogate for river mile. In these circumstances, the residuals for “field station” were non-randomly distributed and often strongly ordered. This indicates either fitting “pool scale” models for these species and regions, or explicitly model covariances

  5. Bioaccumulation and toxicity of selenium during a life-cycle exposure with desert pupfish (Cyprinodon macularius)

    Science.gov (United States)

    Besser, John M.; Brumbaugh, William G.; Papoulias, Diana M.; Ivey, Chris D.; Kunz, James L.; Annis, Mandy; Ingersoll, Christopher G.

    2012-01-01

    that risks of Se toxicity are low in pupfish habitats. The dietary threshold was about twice as high as the greatest mean Se concentrations reported in midge larvae from seven sites in the Imperial Valley. Whole-body thresholds were greater than mean whole-body Se concentrations reported for field-collected pupfish from three sites and for the sailfin molly (Poecilia latipinna), a potential bioaccumulation surrogate for pupfish, from seven sites.Reduced egg production, although highly variable, was the most sensitive response of pupfish to Se exposure. Toxic effects on egg production (reductions of 24–51 percent relative to controls) occurred in the four highest Se treatments, corresponding to reproductive toxicity thresholds of 7.3 μg/g for Se in diet, 3.4 μg/g in pupfish (whole body), and 4.4 μg/g in pupfish eggs. These thresholds are substantially lower than published Se toxicity values for reproductive effects in other freshwater fish (for example, 17–24 μg/g in eggs). Reduced egg production has not been reported as a sensitive endpoint in Se toxicity studies, although abnormal ovarian development has been reported in Se-exposed fish, and reduced egg production has been reported as a sensitive response of other Cyprinodon pupfish to other environmental stressors.Selenium concentrations in tissues of pupfish, mollies, and diet items from Imperial Valley sites frequently exceeded concentrations associated with reduced pupfish egg production in the laboratory study. Reduced egg production may limit the ability of pupfish populations to persist and recover in Se-contaminated habitats in the Imperial Valley and elsewhere in their limited range. However, these apparent risks of Se toxicity are not supported by recent surveys of desert pupfish populations in the Imperial Valley. These surveys indicated that desert pupfish made up a small, but variable, component of fish communities in Imperial Valley habitats, including sites with increased levels of Se exposure