WorldWideScience

Sample records for dace kalnia modris

  1. DACE - A Matlab Kriging Toolbox

    DEFF Research Database (Denmark)

    2002-01-01

    DACE, Design and Analysis of Computer Experiments, is a Matlab toolbox for working with kriging approximations to computer models.......DACE, Design and Analysis of Computer Experiments, is a Matlab toolbox for working with kriging approximations to computer models....

  2. Turbidity affects foraging success of drift-feeding rosyide dace

    Science.gov (United States)

    Richard M. Zamor; Gary D. Grossman

    2007-01-01

    The effects of suspended sediment on nongame fishes are not well understood. We examined the effects of suspended sediment (i.e., turbidity) on reactive distance and prey capture success at springautumn (12°C) and summer (18°C) temperatures for royside dace Clinostomus funduloides in an artificial stream. Experimental turbidities ranged from 0 to 56...

  3. A stochastic population model to evaluate Moapa dace (Moapa coriacea) population growth under alternative management scenarios

    Science.gov (United States)

    Perry, Russell W.; Jones, Edward; Scoppettone, G. Gary

    2015-07-14

    The primary goal of this research project was to evaluate the response of Moapa dace (Moapa coriacea) to the potential effects of changes in the amount of available habitat due to human influences such as ground water pumping, barriers to movement, and extirpation of Moapa dace from the mainstem Muddy River. To understand how these factors affect Moapa dace populations and to provide a tool to guide recovery actions, we developed a stochastic model to simulate Moapa dace population dynamics. Specifically, we developed an individual based model (IBM) to incorporate the critical components that drive Moapa dace population dynamics. Our model is composed of several interlinked submodels that describe changes in Moapa dace habitat as translated into carrying capacity, the influence of carrying capacity on demographic rates of dace, and the consequent effect on equilibrium population sizes. The model is spatially explicit and represents the stream network as eight discrete stream segments. The model operates at a monthly time step to incorporate seasonally varying reproduction. Growth rates of individuals vary among stream segments, with growth rates increasing along a headwater to mainstem gradient. Movement and survival of individuals are driven by density-dependent relationships that are influenced by the carrying capacity of each stream segment.

  4. Experimental evaluation of rainbow trout Oncorhynchus mykiss predation on longnose dace Rhinichthys cataractae

    Science.gov (United States)

    Turek, Kelly C.; Pegg, Mark A.; Pope, Kevin L.

    2014-01-01

    Laboratory and in-stream enclosure experiments were used to determine whether rainbow trout Oncorhynchus mykiss influence survival of longnose dace Rhinichthys cataractae. In the laboratory, adult rainbow trout preyed on longnose dace in 42% of trials and juvenile rainbow trout did not prey on longnose dace during the first 6 h after rainbow trout introduction. Survival of longnose dace did not differ in the presence of adult rainbow trout previously exposed to active prey and those not previously exposed to active prey ( = 0.28, P = 0.60). In field enclosures, the number of longnose dace decreased at a faster rate in the presence of rainbow trout relative to controls within the first 72 h, but did not differ between moderate and high densities of rainbow trout (F2,258.9 = 3.73, P = 0.03). Additionally, longnose dace were found in 7% of rainbow trout stomachs after 72 h in enclosures. Rainbow trout acclimated to the stream for longer periods had a greater initial influence on the number of longnose dace remaining in enclosures relative to those acclimated for shorter periods regardless of rainbow trout density treatment (F4,148.5 = 2.50, P = 0.04). More research is needed to determine how predation rates will change in natural environments, under differing amounts of habitat and food resources and in the context of whole assemblages. However, if rainbow trout are introduced into the habitat of longnose dace, some predation on longnose dace is expected, even when rainbow trout have no previous experience with active prey.

  5. Long-term persistence, density dependence and effects of climate change on rosyside dace (Cyprinidae)

    Science.gov (United States)

    Gary D. Grossman; Gary Sundin; Robert E. Ratajczak

    2016-01-01

    SummaryWe used long-term population data for rosyside dace (Clinostomus funduloides), a numerically dominant member of a stochastically organised fish assemblage, to evaluate the relative importance of density-dependent and density-independent processes to population...

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

    Science.gov (United States)

    Peter D. Hazelton; Gary D. Grossman

    2009-01-01

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

  7. Isolation and characterization of 21 polymorphic microsatellite loci in the Japanese dace (Tribolodon hakonensis)

    Science.gov (United States)

    Koizumi, Noriyuki; Quinn, Thomas W.; Park, Myeongsoo; Fike, Jennifer A.; Nishida, Kazuya; Takemura, Takeshi; Watabe, Keiji; Mori, Atsushi

    2011-01-01

    Twenty one polymorphic microsatellite loci for the Japanese dace (Tribolodon hakonensis) were isolated and characterized. The number of observed alleles per locus in 32 individuals ranged from 3 to 30. The observed and expected heterozygosities ranged from 0.125 to 0.969 and from 0.175 to 0.973, respectively. All loci conformed to Hardy–Weinberg equilibrium, no linkage disequilibrium was observed between pairs of loci and no loci showed evidence of null alleles. These microsatellite loci will be useful for investigating the intraspecific genetic variation and population structure of this species.

  8. Small founding number and low genetic diversity in an introduced species exhibiting limited invasion success (speckled dace, Rhinichthys ocsulus)

    Science.gov (United States)

    Andrew Kinziger; Rodney Nakamoto; Eric Anderson; Bret Harvey

    2011-01-01

    Molecular evaluations of successful invaders are common, however studies of introduced species that have had limited invasion success, or have died out completely, are rare. We studied an introduced population of speckled dace (Rhinichthys osculus) from northern California, USA that has rapidly increased in abundance but remained restricted to a 25-km stretch of river...

  9. Effect of temperature on the effectiveness of artificial reproduction of dace [Cyprinidae (Leuciscus leuciscus (L.))] under laboratory and field conditions.

    Science.gov (United States)

    Nowosad, Joanna; Targońska, Katarzyna; Chwaluczyk, Rafał; Kaszubowski, Rafał; Kucharczyk, Dariusz

    2014-10-01

    This study sought to determine the effect of water temperature on the effectiveness of artificial reproduction of dace brooders under laboratory and field conditions. Three temperatures were tested in the laboratory: 9.5, 12 and 14.5 °C (± 0.1 °C). The water temperature under field conditions was 11.0 ± 0.3 °C (Czarci Jar Fish Farm) and 13.2 ± 1.4 °C (Janowo Fish Farm). The study showed that artificial reproduction of dace is possible in all the temperature ranges under study and an embryo survival rate of over 87% can be achieved. Dace has also been found to be very sensitive to rapid temperature changes, even within the temperature ranges optimal for the species. Such changes have an adverse effect on the outcome of the reproduction process, such as a decrease in the percentage of reproducing females, a decrease in the pseudo-gonado-somatic index (PGSI) and a decrease in the embryo survival rate. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Threshold responses of Blackside Dace (Chrosomus cumberlandensis) and Kentucky Arrow Darter (Etheostoma spilotum) to stream conductivity

    Science.gov (United States)

    Hitt, Nathaniel P.; Floyd, Michael; Compton, Michael; McDonald, Kenneth

    2016-01-01

    Chrosomus cumberlandensis (Blackside Dace [BSD]) and Etheostoma spilotum (Kentucky Arrow Darter [KAD]) are fish species of conservation concern due to their fragmented distributions, their low population sizes, and threats from anthropogenic stressors in the southeastern United States. We evaluated the relationship between fish abundance and stream conductivity, an index of environmental quality and potential physiological stressor. We modeled occurrence and abundance of KAD in the upper Kentucky River basin (208 samples) and BSD in the upper Cumberland River basin (294 samples) for sites sampled between 2003 and 2013. Segmented regression indicated a conductivity change-point for BSD abundance at 343 μS/cm (95% CI: 123–563 μS/cm) and for KAD abundance at 261 μS/cm (95% CI: 151–370 μS/cm). In both cases, abundances were negligible above estimated conductivity change-points. Post-hoc randomizations accounted for variance in estimated change points due to unequal sample sizes across the conductivity gradients. Boosted regression-tree analysis indicated stronger effects of conductivity than other natural and anthropogenic factors known to influence stream fishes. Boosted regression trees further indicated threshold responses of BSD and KAD occurrence to conductivity gradients in support of segmented regression results. We suggest that the observed conductivity relationship may indicate energetic limitations for insectivorous fishes due to changes in benthic macroinvertebrate community composition.

  11. Feminization of Longnose Dace (Rhinichthys cataractae in the Oldman River, Alberta, (Canada Provides Evidence of Widespread Endocrine Disruption in an Agricultural Basin

    Directory of Open Access Journals (Sweden)

    Joyce S. Evans

    2012-01-01

    Full Text Available We sampled an abundant, native minnow (Longnose dace—Rhinichthys cataractae throughout the Oldman River, Alberta, to determine physiological responses and possible population level consequences from exposure to compounds with hormone-like activity. Sex ratios varied between sites, were female-biased, and ranged from just over 50% to almost 90%. Histological examination of gonads revealed that at the sites with >60% females in the adult population, there was up to 38% occurrence of intersex gonads in fish identified through visual examination of the gonads as male. In the majority of intersex gonad cases, there was a large proportion (approx., 50% of oocytes within the testicular tissue. In male dace, vitellogenin mRNA expression generally increased with distance downstream. We analyzed river water for 28 endocrine disrupting compounds from eight functional classes, most with confirmed estrogen-like activity, including synthetic estrogens and hormone therapy drugs characteristic of municipal wastewater effluent, plus natural hormones and veterinary pharmaceuticals characteristic of livestock production. The spatial correlation between detected chemical residues and effects to dace physiology indicate that multiple land uses have a cumulative impact on dace in the Oldman River and effects range from altered gene regulation to severely female-biased sex ratios.

  12. Postglacial recolonization of eastern Blacknose Dace,Rhinichthys atratulus(Teleostei: Cyprinidae), through the gateway of New England.

    Science.gov (United States)

    Tipton, Michelle L; Gignoux-Wolfsohn, Sarah; Stonebraker, Phoebe; Chernoff, Barry

    2011-11-01

    During the last ice age, much of North America far south as 40°N was covered by glaciers (Hewitt 2000). About 20,000 years ago, as the glaciers retreated, the hydrologic landscape changed dramatically creating waterways for fish dispersal. The number of populations responsible for recolonization and the regions from which they recolonized are unknown for many freshwater fishes living in New England and southeastern Canada. The Blacknose Dace,Rhinichthys atratulus, is one of the freshwater fish species that recolonized this region. We hypothesize that the earliest deglaciated region, modern-day Connecticut, was recolonized byR. atratulusvia a single founding event by a single population. In this paper, we test this hypothesis phylogenetically with regard to the major drainage basins within Connecticut. The mitochondrial DNA exhibits low nucleotide diversity, high haplotype diversity, and a dominant haplotype found across the state. A small percentage of individuals in the Housatonic drainage basin, however, share a haplotype with populations in New York drainage basins, a haplotype not found elsewhere in Connecticut's drainage basins. We calculated a range for the rate of divergence for NADH dehydrogenase subunit 2 (nd2) and control region (ctr) of 4.43-6.76% and 3.84-8.48% per million years (my), respectively. While this range is higher than the commonly accepted rate of 2% for mitochondrial DNA, these results join a growing list of publications finding high rates of divergence for various taxa (Peterson and Masel 2009). The data support the conclusion that Connecticut as a whole was recolonized initially by a single founding event that came from a single refugium. Subsequently, the Housatonic basin alone experienced a secondary recolonization event.

  13. Kto takije utopajushtshije i kak ihh spasti? / Modris Auzins

    Index Scriptorium Estoniae

    Auzins, Modris

    2003-01-01

    Inimõiguste eest võitlevad Läti valitsusvälised organisatsioonid osalesid ÜRO rassilise diskrimineerimise likvideerimise komitee sessioonil. Naturalisatsiooniprotsessi ja venekeelse koolihariduse probleem Lätis

  14. Tamula rannaala planeering = Competition of spatial planning of the Tamula lakeside area, Võru / Dace Kalvane

    Index Scriptorium Estoniae

    Kalvane, Dace

    2008-01-01

    Žürii liige Võru Tamula järve rannaala mahulise planeeringu rahvusvahelisest ideekonkursist, auhinnatud töödest. Võidutöö "Lust" autorid on Kaie Enno, Leles Luhse, Maria Zeleznova ja Rein Ailt (Kaie Enno Arhitektuuribüroo)

  15. Development of a sperm cryopreservation protocol for redside dace, Clinostomus elongatus: implications for genome resource banking

    DEFF Research Database (Denmark)

    Butts, Ian A.E.; Mokdad, A.; Trippel, E.A.

    2013-01-01

    of extirpation.We developed cryopreservation protocols by testing the effects of diluent (buffered sperm motility-inhibiting saline solution [BSMIS]; BSMIS + glycine; sucrose; and Hanks’ balanced salt solution [HBSS]), cryoprotectant (dimethyl sulfoxide [DMSO]; propylene glycol [PG]; N,N-dimethylacetamide [DMA...... rate was not significant for BSMIS + glycine or for HBSS, but an effect was detected for sucrose, with sperm frozen at 5◦C/min or 10◦C/min having higher motility than sperm frozen at 1◦C/min. The effect of extender was not significant at 1◦C/min or 5◦C/min, but an effect was detected at 10◦C...

  16. A DACE study on a three stage metal forming process made of Sandvik Nanoflex

    NARCIS (Netherlands)

    Post, J.; Klaseboer, G.; Stinstra, E.; Huetink, Han

    2004-01-01

    Sandvik NanoflexTM combines good corrosion resistance with high strength. The steel has good deformability in austenitic conditions. This material belongs to the group of metastable austenites, so during deformation a straininduced transformation into martensite takes place. After deformation, the

  17. 77 FR 76065 - Endangered and Threatened Wildlife and Plants; Draft Revised Recovery Plan for Kendall Warm...

    Science.gov (United States)

    2012-12-26

    ...] Endangered and Threatened Wildlife and Plants; Draft Revised Recovery Plan for Kendall Warm Springs Dace... revised recovery plan for the Kendall Warm Springs dace (Rhinichthys osculus thermalis). This species is... recovery plan. The Kendall Warm Springs dace (Rhinichthys osculus thermalis), found only in one location in...

  18. M-X Environmental Technical Report. Environmental Characteristics of Alternative Designated Deployment Areas, Protected Species.

    Science.gov (United States)

    1980-12-22

    purple- spined hedgehog cactus (Echinocereus engelmanii var. purpureus), the Siler pin- cushion cactus (Pediocactus sileri), and the dwarf bear poppy...WHITE RIVER SPINE DACE K WHITE RIVER DESERT SUCKER L WHITE RIVER SPRINGFISH M PAHRANAGAT ROUNDTAIL CHUB* N PAHRUMP KILLIFISH" O MOAPA DACE* P LAHONTAN

  19. Evaluation of protected, threatened, and endangered fish species in Upper Bear Creek watershed

    International Nuclear Information System (INIS)

    Ryon, M.G.

    1998-07-01

    The East Bear Creek Site for the proposed centralized waste facility on the US Department of Energy's Oak Ridge Reservation was evaluated for potential rare, threatened or endangered (T and E) fish species in the six primary tributaries and the main stem of Bear Creek that are within or adjacent to the facility footprint. These tributaries and portion of Bear Creek comprise the upper Bear Creek watershed. One T and E fish species, the Tennessee dace (Phoxinus tennesseensis), was located in these streams. The Tennessee dace is listed by the State of Tennessee as being in need of management, and as such its habitat is afforded some protection. Surveys indicated that Tennessee dace occupy the northern tributaries NT-1, NT-4, and NT-5, as well as Bear Creek. Several specimens of the dace were gravid females, indicating that the streams may function as reproductive habitat for the species. The implications of impacts on the species are discussed and mitigation objectives are included

  20. Valmiera kunstnikud Viljandis / Guna Kalnaca

    Index Scriptorium Estoniae

    Kalnaca, Guna

    1998-01-01

    Valmiera kunsti päevadest Viljandis, kus osalevad 5 professionaalset kunstnikku Valmierast : Dace Bluma-portselan, Vineta Dzervite-graafika, Antra Galzons-maalid, Janis Galzons-maalid, Andris Varpa-skulptuurid. Kunstnike loomingu lühitutvustus.

  1. Dual Axis Controller for Extreme Environments, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Dual Axis Controller for Extreme Environments (DACEE) addresses a critical need of NASA's future exploration plans to investigate extreme environments within our...

  2. "ma jätkuvalt vaikin palju ja võimsalt ..." = "es turpinu daudz un spċ̋gi klusṫ ..." = "jeg forsetter å tie mye og heftig ..." : [luuletused] / Dace Sparńe ; tlk. Maima Gr̋nberga, Snorre Karkonens-Svensons

    Index Scriptorium Estoniae

    Sparńe, Dace

    2004-01-01

    Sisu: "ma jätkuvalt vaikin palju ja võimsalt ..." = "es turpinu daudz un spċ̋gi klusṫ ..." = "jeg forsetter å tie mye og heftig ..."; "luba ..." = "apsoli ..." = "lov meg ..."; "punane roos jah-sõna inkarnatsioonina alati ..." = "sarkana roze ḱ j́vŕda inkarnćija b͠s vienmṙ ..." = "en rıd rose forblir inkarnasjonen av jaordet bestandig ..."

  3. The question about paleoinformatics

    Science.gov (United States)

    Vartic, Andrei

    2006-12-01

    The author is treating questions about development of informatics in ancient Dacia during Y-th Century B.C. - 2-nd Century A.C. He is introducing a new terminology (paleoinformatics) in view of defining the interests of Daces in numbering, the elementary numbers theory and various aspects of numbers representation. A relation between elementary numbers theory and informatisation has been discussed. A particular interest has been given to calculation of the Circle length/Diameter ratio (number Pi), its calculation by Daces.

  4. 78 FR 69374 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2013-11-19

    ... these species is captured dead or deemed nonviable, it would be retained for genetic analysis. The... Speckled Dace based on genetic and morphological data. The genetic sequence data would be used to better... salmonid populations. In addition, any new data regarding listed species presence would be used to inform...

  5. An emergent multiple predator effect may enhance biotic resistance in a stream fish assemblage

    Science.gov (United States)

    Bret C. Harvey; Jason L. White; Rodney J. Nakamoto

    2004-01-01

    While two cyprinid fishes introduced from nearby drainages have become widespread and abundant in the Eel River of northwestern California, a third nonindigenous cyprinid has remained largely confined to <25 km of one major tributary (the Van Duzen River) for at least 15 years. The downstream limit of this species, speckled dace, does not appear to correspond...

  6. The Environmental Assessment and Management (TEAM) Guide: New Mexico Supplement

    Science.gov (United States)

    2010-03-01

    dace, Phoxinus erythrogaster (j) Colorado pikeminnow, Ptychocheilus lucius (k) loach minnow, Tiaroga cobitis 5-13 Natural Resources Management...writing by the Department, off-site at a readily available location. ST.4.38.NM. Corrective actions must be ta ken u pon a release involving a...cause a public nuisance or threat to human health, safety and welfare, or the environment. Verify th at when c ontaminated s oil is ta ken o ff s ite

  7. Vegetation and Grazing in the St. Katherine Protectorate, South ...

    African Journals Online (AJOL)

    5. Grazing pressure. 1. 2. 3. 4. 5. P lant health. Unk . La bita e. Le gu m ino s a e. Co m p o sita e. A m ara nthac ea e. B ora gin ace ae. C h en opo dia c e ae. E u ph orb iac ea e. S cro ph ula ria cea e. A sc lep id ac e ae. C a ry o phy lla cea e. R ese dace ae. C a pp arace ae. Cuc urb ita cea e. Cruc ife rae. Gram inae. U m be.

  8. Burst Speed of Wild Fishes under High-Velocity Flow Conditions Using Stamina Tunnel with Natural Guidance System in River

    Science.gov (United States)

    Izumi, Mattashi; Yamamoto, Yasuyuki; Yataya, Kenichi; Kamiyama, Kohhei

    Swimming experiments were conducted on wild fishes in a natural guidance system stamina tunnel (cylindrical pipe) installed in a fishway of a local river under high-velocity flow conditions (tunnel flow velocity : 211 to 279 cm·s-1). In this study, the swimming characteristics of fishes were observed. The results show that (1) the swimming speeds of Tribolodon hakonensis (Japanese dace), Phoxinus lagowshi steindachneri (Japanese fat-minnow), Plecoglossus altivelis (Ayu), and Zacco platypus (Pale chub) were in proportion to their body length under identical water flow velocity conditions; (2) the maximum burst speed of Japanese dace and Japanese fat-minnow (measuring 4 to 6 cm in length) was 262 to 319 cm·s-1 under high flow velocity conditions (225 to 230 cm·s-1), while the maximum burst speed of Ayu and Pale chub (measuring 5 cm to 12 cm in length) was 308 to 355 cm·s-1 under high flow velocity conditions (264 to 273 cm·s-1) ; (3) the 50cm-maximum swimming speed of swimming fishes was 1.07 times faster than the pipe-swimming speed; (4) the faster the flow velocity, the shorter the swimming distance became.

  9. Coexistence of fish species in a large lowland river: food niche partitioning between small-sized percids, cyprinids and sticklebacks in submersed macrophytes.

    Science.gov (United States)

    Dukowska, Małgorzata; Grzybkowska, Maria

    2014-01-01

    In the spring and summer of each year, large patches of submersed aquatic macrophytes overgrow the bottom of the alluvial Warta River downstream of a large dam reservoir owing to water management practices. Environmental variables, macroinvertebrates (zoobenthos and epiphytic fauna, zooplankton) and fish abundance and biomass were assessed at this biologically productive habitat to learn intraseasonal dynamics of food types, and their occurrence in the gut contents of small-sized roach, dace, perch, ruffe and three-spined stickleback. Gut fullness coefficient, niche breadth and niche overlap indicated how the fishes coexist in the macrophytes. Chironomidae dominated in the diet of the percids. However, ruffe consumed mostly benthic chironomids, while perch epiphytic chironomids and zooplankton. The diet of dace resembled that in fast flowing water although this rheophilic species occurred at unusual density there. The generalist roach displayed the lowest gut fullness coefficient values and widest niche breadth; consequently, intraspecific rather than interspecific competition decided the fate of roach. Three-spined stickleback differed from the other fishes by consuming epiphytic simuliids and fish eggs. The diet overlap between fishes reaching higher gut fullness coefficient values was rather low when the food associated with the submersed aquatic macrophytes was most abundant; this is congruent with the niche overlap hypothesis that maximal tolerable niche overlap can be higher in less intensely competitive conditions.

  10. Geochemical pathways and biological uptake of radium in small Canadian Shield lakes

    International Nuclear Information System (INIS)

    Hesslein, R.H.; Slavicek, E.

    1984-01-01

    The sediment-water interactions and biological uptake of 226 Ra are described for four small Canadian Shield lakes at the Experimental Lakes Area, Kenora, Ontario. A single addition of 226 Ra was made to each lake between 1970 and 1976. Approximately 90 percent of the added 226 Ra initially sorbed to the sediments. Outflow from the lakes showed losses of only 5-11 percent 226 Ra per year. Models are proposed for adsorption and outflow of 226 Ra from lakes. Biological uptake and long-term 226 Ra concentrations were measured in three species of macrophytes, crayfish, and five species of fish. Bioaccumulation ranged from 1100 to 5000 in macrophytes, 705 in crayfish, from 30 to 80 in large trout (Salvelinus namaycush), white sucker (Catostomus commersoni), and lake whitefish (Coregonus clupeaformis), and from 230 to 1200 in fathead minnows (Pimephales promelas), pearl dace (Semotilus margarita), and northern redbelly dace (Chrosomus eos). The concept of Ra/Ca ratio in organisms versus water and food is used to explain the differences in bioaccumulation. 226 Ra is discriminated against versus calcium by fish but favoured by macrophytes and crayfish

  11. Relative distribution and abundance of fishes and crayfish in 2010 and 2014 prior to saltcedar (Tamarix ssp.) removal in the Amargosa River Canyon, southeastern California

    Science.gov (United States)

    Hereford, Mark E.

    2016-07-22

    The Amargosa River Canyon, located in the Mojave Desert of southeastern California, contains the longest perennial reach of the Amargosa River. Because of its diverse flora and fauna, it has been designated as an Area of Critical Environmental Concern and a Wild and Scenic River by the Bureau of Land Management. A survey of fishes conducted in summer 2010 indicated that endemic Amargosa River pupfish (Cyprinodon nevadensis amargosae) and speckled dace (Rhinichthys osculus spp.) were abundant and occurred throughout the Amargosa River Canyon. The 2010 survey reported non-native red swamp crayfish (Procambarus clarkii) and western mosquitofish (Gambusia affinis) captures were significantly higher, whereas pupfish captures were lower, in areas dominated by non-native saltcedar (Tamarix ssp.). Based on the 2010 survey, it was hypothesized that the invasion of saltcedar could result in a decrease in native species. In an effort to maintain and enhance native fish populations, the Bureau of Land Management removed saltcedar from a 1,550 meter reach of stream on the Amargosa River in autumn 2014 and autumn 2015. Prior to the removal of saltcedar, a survey of fishes and crayfish using baited minnow traps was conducted in the treatment reach to serve as a baseline for future comparisons with post-saltcedar removal surveys. During the 2014 survey, 1,073 pupfish and 960 speckled dace were captured within the treatment reach. Catch per unit effort of pupfish and speckled dace in the treatment reach was less in 2014 than in 2010, although differences could be owing to seasonal variation in capture probability. Non-native mosquitofish catch per unit effort decreased from 2010 to 2014; however, the catch per unit effort of crayfish increased from 2010 to 2014. Future monitoring efforts of this reach should be conducted at the same time period to account for potential seasonal fluctuations of abundance and distribution of fishes and crayfish. A more robust study design that

  12. Studies on water turbine runner which fish can pass through: In case of single stage axial runner

    International Nuclear Information System (INIS)

    Shimizu, Yukimari; Maeda, Takao; Nagoshi, Osamu; Ieda, Kazuma; Shinma, Hisako; Hagimoto, Michiko

    1994-01-01

    The relationship between water turbine runner design and operation and the safe passage of fish through the turbine is studied. The kinds of fish used in the tests are a dace, a sweet fish and a small salmon. A single stage axial runner is used. The velocity and pressure distributions were measured inside the turbine casing and along the casing wall. Many pictures showing fish passing through the rotating runner were taken and analyzed. The swimming speed of the fish was examined from video recordings. Fish pass through the runner more rapidly when they can determine and choose the easier path. Injury and mortality of fish are affected by the runner speed and the location of impact of the runner on the fish body

  13. Fish species of greatest conservation need in wadeable Iowa streams: current status and effectiveness of Aquatic Gap Program distribution models

    Science.gov (United States)

    Sindt, Anthony R.; Pierce, Clay; Quist, Michael C.

    2012-01-01

    Effective conservation of fish species of greatest conservation need (SGCN) requires an understanding of species–habitat relationships and distributional trends. Thus, modeling the distribution of fish species across large spatial scales may be a valuable tool for conservation planning. Our goals were to evaluate the status of 10 fish SGCN in wadeable Iowa streams and to test the effectiveness of Iowa Aquatic Gap Analysis Project (IAGAP) species distribution models. We sampled fish assemblages from 86 wadeable stream segments in the Mississippi River drainage of Iowa during 2009 and 2010 to provide contemporary, independent fish species presence–absence data. The frequencies of occurrence in stream segments where species were historically documented varied from 0.0% for redfin shiner Lythrurus umbratilis to 100.0% for American brook lampreyLampetra appendix, with a mean of 53.0%, suggesting that the status of Iowa fish SGCN is highly variable. Cohen's kappa values and other model performance measures were calculated by comparing field-collected presence–absence data with IAGAP model–predicted presences and absences for 12 fish SGCN. Kappa values varied from 0.00 to 0.50, with a mean of 0.15. The models only predicted the occurrences of banded darterEtheostoma zonale, southern redbelly dace Phoxinus erythrogaster, and longnose daceRhinichthys cataractae more accurately than would be expected by chance. Overall, the accuracy of the twelve models was low, with a mean correct classification rate of 58.3%. Poor model performance probably reflects the difficulties associated with modeling the distribution of rare species and the inability of the large-scale habitat variables used in IAGAP models to explain the variation in fish species occurrences. Our results highlight the importance of quantifying the confidence in species distribution model predictions with an independent data set and the need for long-term monitoring to better understand the

  14. Potential population and assemblage influences of non-native trout on native nongame fish in Nebraska headwater streams

    Science.gov (United States)

    Turek, Kelly C.; Pegg, Mark A.; Pope, Kevin L.; Schainost, Steve

    2014-01-01

    Non-native trout are currently stocked to support recreational fisheries in headwater streams throughout Nebraska. The influence of non-native trout introductions on native fish populations and their role in structuring fish assemblages in these systems is unknown. The objectives of this study were to determine (i) if the size structure or relative abundance of native fish differs in the presence and absence of non-native trout, (ii) if native fish-assemblage structure differs in the presence and absence of non-native trout and (iii) if native fish-assemblage structure differs across a gradient in abundances of non-native trout. Longnose dace Rhinichthys cataractae were larger in the presence of brown trout Salmo trutta and smaller in the presence of rainbow trout Oncorhynchus mykiss compared to sites without trout. There was also a greater proportion of larger white suckers Catostomus commersonii in the presence of brown trout. Creek chub Semotilus atromaculatus and fathead minnow Pimephales promelas size structures were similar in the presence and absence of trout. Relative abundances of longnose dace, white sucker, creek chub and fathead minnow were similar in the presence and absence of trout, but there was greater distinction in native fish-assemblage structure between sites with trout compared to sites without trout as trout abundances increased. These results suggest increased risk to native fish assemblages in sites with high abundances of trout. However, more research is needed to determine the role of non-native trout in structuring native fish assemblages in streams, and the mechanisms through which introduced trout may influence native fish populations.

  15. Food web analysis reveals effects of pH on mercury bioaccumulation at multiple trophic levels in streams

    Energy Technology Data Exchange (ETDEWEB)

    Jardine, Timothy D., E-mail: tim.jardine@usask.ca [Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, NB E2L 4L5 (Canada); Kidd, Karen A. [Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, NB E2L 4L5 (Canada); O’ Driscoll, Nelson [Department of Earth and Environmental Sciences, Acadia University, Wolfville, NS B4P 2R6 (Canada)

    2013-05-15

    Highlights: ► We examine biomagnification of Hg through stream food webs using δ15 N. ► Slopes of methyl Hg vs. trophic level were higher than total Hg vs. trophic level. ► Biomagnification from predatory insects to fish was related to pH of the water. ► Biomagnification at lower trophic levels was related to dietary concentrations. ► These trends can explain variation in field-measured Hg in food webs. -- Abstract: Biomagnification processes and the factors that govern them, including those for mercury (Hg), are poorly understood in streams. Total and methyl Hg concentrations and relative trophic position (using δ{sup 15}N) were analyzed in biofilm and invertebrates from 21 streams in New Brunswick, Canada to assess food web biomagnification leading to the common minnow blacknose dace (Rhinichthys atratulus), a species known to have Hg concentrations that are higher in low pH waters. Biomagnification slopes within stream food webs measured using Hg vs. δ{sup 15}N or corresponding trophic levels (TL) differed depending on the chemical species analyzed, with total Hg exhibiting increases of 1.3–2.5 per TL (mean slope of total Hg vs. δ{sup 15}N = 0.14 ± 0.06 S.D., range = 0.06–0.20) and methyl Hg showing a more pronounced increase of 2.8 to 6.0 per TL (mean slope of methyl Hg vs. δ{sup 15}N = 0.30 ± 0.08 S.D., range = 0.22–0.39). While Hg biomagnification slopes through the entire food web (Trophic Magnification Factors, TMFs) were not influenced by water chemistry (pH), dietary concentrations of methyl Hg strongly influenced biomagnification factors (BMFs) for consumer-diet pairs within the food web at lower trophic levels, and BMFs between dace and predatory invertebrates were significantly higher in low pH waters. These analyses, coupled with observations of higher Hg in primary producers in streams with low pH, suggest that pH influences both baseline concentrations and biomagnification of Hg in these systems. Because higher Hg

  16. Food web analysis reveals effects of pH on mercury bioaccumulation at multiple trophic levels in streams

    International Nuclear Information System (INIS)

    Jardine, Timothy D.; Kidd, Karen A.; O’ Driscoll, Nelson

    2013-01-01

    Highlights: ► We examine biomagnification of Hg through stream food webs using δ15 N. ► Slopes of methyl Hg vs. trophic level were higher than total Hg vs. trophic level. ► Biomagnification from predatory insects to fish was related to pH of the water. ► Biomagnification at lower trophic levels was related to dietary concentrations. ► These trends can explain variation in field-measured Hg in food webs. -- Abstract: Biomagnification processes and the factors that govern them, including those for mercury (Hg), are poorly understood in streams. Total and methyl Hg concentrations and relative trophic position (using δ 15 N) were analyzed in biofilm and invertebrates from 21 streams in New Brunswick, Canada to assess food web biomagnification leading to the common minnow blacknose dace (Rhinichthys atratulus), a species known to have Hg concentrations that are higher in low pH waters. Biomagnification slopes within stream food webs measured using Hg vs. δ 15 N or corresponding trophic levels (TL) differed depending on the chemical species analyzed, with total Hg exhibiting increases of 1.3–2.5 per TL (mean slope of total Hg vs. δ 15 N = 0.14 ± 0.06 S.D., range = 0.06–0.20) and methyl Hg showing a more pronounced increase of 2.8 to 6.0 per TL (mean slope of methyl Hg vs. δ 15 N = 0.30 ± 0.08 S.D., range = 0.22–0.39). While Hg biomagnification slopes through the entire food web (Trophic Magnification Factors, TMFs) were not influenced by water chemistry (pH), dietary concentrations of methyl Hg strongly influenced biomagnification factors (BMFs) for consumer-diet pairs within the food web at lower trophic levels, and BMFs between dace and predatory invertebrates were significantly higher in low pH waters. These analyses, coupled with observations of higher Hg in primary producers in streams with low pH, suggest that pH influences both baseline concentrations and biomagnification of Hg in these systems. Because higher Hg concentrations in the diets

  17. [Investigation on sanitation of freshwater aquaculture environments and Clonorchis sinensis intermediate host infection in a city of Pearl River Delta region, China].

    Science.gov (United States)

    Man, Wang; Le, Luo; Xue-Qin, Chen; Lei, Li; Yue-Yi, Fang

    2017-10-19

    To understand the current status of the sanitation of freshwater aquaculture environments, and Clonorchis sinensis infection of freshwater fish in the aquaculture and market in a city of Pearl River Delta region, so as to provide the evidence for formulating the prevention and control strategy of clonorchiasis sinensis. In 2016, based on the distribution of freshwater aquaculture, 36 freshwater fish ponds among 14 towns were selected for sampling and investigation, and 10-20 pieces were collected from each pond. Besides, 3 aquatic product wholesale markets were included, among which 3-6 stalls were selected from each market, and 20-30 pieces were collected from each stall. The metacercaria in the fish was examined by the digestion method. In the 36 fish ponds, there were no toilets with the stool being drained into fish ponds directly, and there was only one pond with duck sheds with the stool being drained into fish ponds directly. Totally 437 pieces of freshwater fish from ponds were detected, with a metacercaria positive rate of 4.35% (19/437). The metacercaria positive fish were distributed in 50% (7/14) of towns and 25% (9/36) ponds. The positive rates of crucian carp, grass carp, dace, aristichthysnobilis, and tilapia were 13.95% (6/43), 4.76% (9/189), 4.44 (2/45), 1.55% (2/129), and 0 (0/31) respectively, with statistically significant difference ( χ 2 = 13.46, P = 0.01). Totally 307 pieces of freshwater fish were collected from the wholesale markets, with a total positive rate of 1.95% (6/307). The positive rate of grass carp and aristichthysnobilis were 3.20% (4/125) and 2.78% (2/72) respectively, and no positive samples were found in crucian carp, dace and tilapia, with no statistically significant difference among the different fish in the infection rate (Fisher exact P = 0.75). The sanitation of freshwater aquaculture environments in a city of Pearl River Delta region is relative good. However, there are different degrees of Clonorchis sinensis

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

    Science.gov (United States)

    Chelgren, Nathan D; Dunham, Jason B

    2015-07-01

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

  19. Review of fish diversity in the Lake Huron basin

    Science.gov (United States)

    Roseman, E.F.; Schaeffer, J.S.; Steen, P.J.

    2009-01-01

    Lake Huron has a rich aquatic habitat diversity that includes shallow embayments, numerous tributaries, shallow mid-lake reef complexes, archipelagos, and profundal regions. These habitats provide support for warm, cool, and cold water fish communities. Diversity of fishes in Lake Huron reflects post-glaciation colonization events, current climate conditions, accidental and intentional introductions of non-indigenous species, and extinctions. Most extinction events have been largely associated with habitat alterations, exploitation of fisheries, and interactions with non-indigenous species. The most recent historical survey of extirpated and imperiled species conducted in the late 1970s identified 79 fish species in Lake Huron proper and about 50 additional species in tributaries. Of those 129 species, 20 are now considered extirpated or imperiled. Extirpated species include Arctic grayling, paddlefish, weed shiner, deepwater cisco, blackfin cisco, shortnose cisco, and kiyi. Six species have declined appreciably due to loss of clear-water stream habitat: the river redhorse, river darter, black redhorse, pugnose shiner, lake chubsucker, redside dace, eastern sand darter, and channel darter. While numerous agencies, universities, and other organizations routinely monitor nearshore and offshore fish distribution and abundance, there is a need for more rigorous examination of the distribution and abundance of less-common species to better understand their ecology. This information is critical to the development of management plans aimed at ecosystem remediation and restoration.

  20. pH tolerance of Daphnia pulex (leydig, emend. , richard)

    Energy Technology Data Exchange (ETDEWEB)

    Davis, P; Ozburn, G W

    1969-01-01

    The survival time and reproduction of female Daphnia pulex in solutions varying in pH have been observed. Dilute sodium hydroxide or sulfuric acid solutions were added to four different diluent waters: distilled water, aerated tap water, aerated and filtered tap water from an aquarium containing Dace minnows, and Mcintyre River water. D. Pulex (initially up to 72 hours old) survived for the duration of the experiment (32 hours) in river water within a pH range of 6.1 to 10.3; in aquarium water within a pH range of 4.3 to 10.4; only at pH 6.4 and pH 7.6 in distilled water; and in none of the solutions using aerated tap water. The dissolved oxygen content was measured at the beginning and end of every experiment and was found never to fall below 6.2 p.p.M. Those individuals which survived were cultured in the laboratory and parthenogenesis was observed at pH values between 7.0 and 8.7.

  1. Ar neatliekamās medicīniskās palīdzības brigādēm stacionārā nogādāto pacientu apmierinātība ar veselības aprūpi pirms stacionāra un stacionāra etapā

    OpenAIRE

    Dzene, Dace

    2017-01-01

    Autore: Dace Dzene, stud.apl.nr. dd15034 Darba vadītājs: Dr.med. Igors Ivanovs Ar neatliekamās medicīniskās palīdzības brigādēm stacionārā nogādāto pacientu apmierinātība ar veselības aprūpi pirms stacionāra un stacionāra etapā. Maģistra darbs, Latvijas universitāte, Rīga, 2017. Darbs sastāv no teorētiskās un empīriskās daļas, 6 nodaļām, 66 lapām, 29 attēliem, 10 tabulām, 2 pielikumiem. Pētījuma mērķis ir noskaidrot pacientu apmierinātību ar saņemto veselības aprūpes kvalitāti pirms st...

  2. Performance of an Underground Stormwater Detention Chamber and Comparison with Stormwater Management Ponds

    Directory of Open Access Journals (Sweden)

    Jennifer Drake

    2016-05-01

    Full Text Available The transportation of pollutants from impervious surfaces during runoff events to receiving water bodies is a serious environmental problem. Summer runoff is also heated by impervious surfaces, causing thermal enrichment in receiving water body systems and degradation of coldwater aquatic ecosystems. End-of-pipe stormwater management facilities that are open to the environment can result in further elevated temperatures due to exposure to solar radiation. Receiving water systems that provide coldwater habitat require cool water temperatures to sustain healthy conditions for cold water flora and fauna (e.g., trout, dace. Underground Stormwater Detention Chambers (USDC are a technology for the detention and treatment of stormwater runoff that can potentially solve the thermal issues associated with sun-exposed detention facilities while still providing an equivalent level of treatment services for stormwater pollutants. A field study of an USDC located in Southern Ontario was undertaken to characterize its treatment performance and effect on water temperature. The results were: the USDC was found to provide similar levels of stormwater treatment as wet detention ponds. On average, outlet maximum temperatures were 5 °C cooler than inlet maximum temperatures, and outlet water temperatures remained within the thermal regime for coldwater fish habitat throughout the evaluation period. There was little to no stratification of temperature, nor dissolved solids, but stratification of dissolved oxygen was observed mid-winter and into the spring.

  3. Acute toxicity of zinc to several aquatic species native to the Rocky Mountains.

    Science.gov (United States)

    Brinkman, Stephen F; Johnston, Walter D

    2012-02-01

    National water-quality criteria for the protection of aquatic life are based on toxicity tests, often using organisms that are easy to culture in the laboratory. Species native to the Rocky Mountains are poorly represented in data sets used to derive national water-quality criteria. To provide additional data on the toxicity of zinc, several laboratory acute-toxicity tests were conducted with a diverse assortment of fish, benthic invertebrates, and an amphibian native to the Rocky Mountains. Tests with fish were conducted using three subspecies of cutthroat trout (Colorado River cutthroat trout Oncorhynchus clarkii pleuriticus, greenback cutthroat trout O. clarkii stomias, and Rio Grande cutthroat trout O. clarkii virginalis), mountain whitefish (Prosopium williamsoni), mottled sculpin (Cottus bairdi), longnose dace (Rhinichthys cataractae), and flathead chub (Platygobio gracilis). Aquatic invertebrate tests were conducted with mayflies (Baetis tricaudatus, Drunella doddsi, Cinygmula sp. and Ephemerella sp.), a stonefly (Chloroperlidae), and a caddis fly (Lepidostoma sp.). The amphibian test was conducted with tadpoles of the boreal toad (Bufo boreas). Median lethal concentrations (LC(50)s) ranged more than three orders of magnitude from 166 μg/L for Rio Grande cutthroat trout to >67,000 μg/L for several benthic invertebrates. Of the organisms tested, vertebrates were the most sensitive, and benthic invertebrates were the most tolerant.

  4. The Feeding Behaviour of Fish from the Upper Lake Baikal Watershed of the Eroo River in Mongolia

    Directory of Open Access Journals (Sweden)

    Sudeep Chandra

    2005-06-01

    Full Text Available The upper Selenge watershed in Mongolia is home to some of the world’s unique fish species. In this study we determined the feeding behaviour of selected fish species collected from the main stream of the Eroo River and two of its upstream tributaries, the Sharlan and Bar Chuluut rivers. Using stable isotope (carbon and nitrogen measurements combined with qualitative and literature information, we determined that taimen ( Hucho taimen and pike ( Esox luceus were the top predators in the Eroo River. They received a substantial amount of their energy from other fish species as well as terrestrial derived sources. Percent presence of biota in lenok ( Brachymystax lenok stomachs demonstrated they eat zoobenthos, invertebrates, fish, and terrestrial rodents. Siberian dace ( Leuciscus baicalensis , a small forage fish collected from the Sharlan and Bar Chuluut rivers demonstrate these fish eat periphyton, zoobenthos and terrestrial invertebrates. In the Bar Chuluut tributary, lenok eat a combination of foods including zoobenthos and other fish species, while arctic grayling ( Thymallus arcticus fed primarily on zoobenthos. Percent frequency analysis showed the two game fish species collected from the Bar Chuluut tributary fed primarily on zoobenthos (85 % for lenok and 80 % for grayling, with 28 families and 10 orders represented in their stomachs. Interviews with families suggested local people fish for a variety of species and that there has been a decline in the catch of taimen and sturgeon ( Acipenser baeri baicalensis over time. Since fishing was poor below highly disturbed areas (e.g. mine sites, local people fished above mine locations or in areas least impacted by these anthropogenic impacts.

  5. Bioaccumulation of radionuclides in fertilized Canadian Shield lake basins

    International Nuclear Information System (INIS)

    Bird, G.A.; Schwartz, W.J.; Hesslein, R.H.; Mills, K.H.; Turner, M.A.

    1998-01-01

    Radionuclide tracers of heavy metals ( 59 Fe, 60 Co, 65 Zn, 75 Se 85 Sr, 134 Cs and 203 Hg) representing potential contamination from nuclear power plants, industry and agriculture were added to separate basins of Lake 226, Experimental Lakes Area, northwestern Ontario. The two basins were part of a eutrophication experiment and differed in their trophic status; the north basin (L226N) was eutrophic whereas the south basin (L226S) was mesotrophic. Our objective was to determine the uptake of the radionuclides by biota and the effect of lake trophic status on their bioaccumulation. The trophic status of the lakes did not appear to have a marked effect on the accumulation of radionuclides by the biota. This may have been because of a mid-summer leakage of nutrients between the basins which enhanced primary production in L226S, because there is a time lag between primary production and the availability of the radionuclides to the fishes or because trophic status does not affect the uptake of at least some of these radionuclides. However, there was a tendency for faster uptake of the radionuclides in L226N by fish than L226S, but the differences were not significant. Concentrations in the biota generally decreased in the order: fathead minnow>pearl dace>tadpoles>slimy sculpin>leeches. Concentrations in biota generally decreased in the order: 65 Zn> 203 Hg> 75 Se> 134 Cs> 60 Co> 85 Sr= 59 Fe. Cobalt-60 concentrations in tadpoles were greater than in the other biota. Radionuclide concentrations in the tissues of lake whitefish indicated that uptake was predominately from food. Radionuclide concentrations were usually higher in the posterior gut, liver and kidney than in other tissues, whereas body burdens were generally high in the muscle for 75 Se, 134 Cs and 203 Hg; kidney and gut for 60 Co; and bone for 65 Zn and 75 Se. Mercury-203 burdens were also high in the bone and gut

  6. Low concentrations of selenium in stream food webs of eastern Canada

    International Nuclear Information System (INIS)

    Jardine, Timothy D.; Kidd, Karen A.

    2011-01-01

    Herbivorous and predatory invertebrates and two species of fish (brook trout and blacknose dace) were collected from 49 streams in New Brunswick, Canada to determine whether concentrations of selenium (Se) in the biota were affected by a point source (a coal-fired power plant), and stream water chemistry (pH, sulphate, conductivity, and total organic carbon), and to determine the trophic transfer of Se through these food webs. Total Se concentrations in the biota were generally low (0.2 to 4.8 μg g -1 dry weight) across sites and there was no relationship between distance from the coal-fired power plant and Se concentrations in invertebrates or fishes. Water chemistry was an equally poor predictor of Se concentrations in invertebrates and fish. Trophic position (determined using δ 15 N) was a significant predictor of Se concentrations in only five of the stream food webs, and two of these had negative slopes, indicating little or no trophic magnification across most systems; many fishes had lower concentrations than their invertebrate prey and trophic transfer was higher at sites with low invertebrate Se concentrations. Variability in Se concentrations in fishes was explained more by site of capture than microhabitat use within the site (as measured with δ 13 C), suggesting among-site differences in geological sources of Se. Because concentrations were below known toxicity thresholds for fish and other consumers, these results suggest that Se is not an environmental issue in New Brunswick streams that do not receive direct inputs from mining activities. - Research Highlights: → Se concentrations in stream invertebrates and fishes in eastern Canada are low. → Concentrations were not related to water chemistry or distance from a point source. → Se did not biomagnify in the food web, yet was almost always in excess of Hg.

  7. Spatial and temporal (1963-2012 variability of ichthyofauna in the large lowland Warta River, Poland

    Directory of Open Access Journals (Sweden)

    Andrzej Kruk

    2015-11-01

    Full Text Available The Warta River is a tributary of the Odra (Oder River. It is 795.2 km long. In 1986 the large Jeziorsko dam reservoir was constructed in the 306th km of its course. In the late 1980s, the river pollution assumed its highest level and stopped increasing as the former political system collapsed and many industrial plants went bankrupt. Unified fish electrocatches have been performed along the Warta River since the 1960s. During the last sampling, in 2011-2012, fish fauna in the middle course of the river was in the poorest condition due to the destabilizing upstream impact of the Jeziorsko dam reservoir, large amounts of wastewater input to the river, and the lack of unpolluted tributaries that could serve as sources of recolonizers. The weakest human pressure was reported for the upper and lower courses, which resulted in higher numbers of species significantly preferring them, and the higher species richness. Species richness significantly increased in comparison with the previous sampling occasions (in 1963-66, 1986-88, and 1996-98. Significant increases in the stability of occurrence, abundance or biomass were recorded for many species including burbot, chub, dace, ide, gudgeon, bleak, bitterling, perch and spined loach. Significant declines in the above mentioned population parameters were rare and related mainly to European eel (a migratory species. The previously recorded strong negative trend (declines in rheophils, increase in the dominance of roach and perch has been reversed. However, regenerated fish assemblages were not recorded in 1996-98 (i.e. several years after the beginning of the improvement in water quality but in 2011-2012 (i.e. about one decade later. We have noticed a similar delay in ichthyofauna recovery also in the Pilica River (Vistula system. This is why we believe that about 15 years are necessary to observe a considerable improvement in fish fauna in larger degraded rivers.

  8. Fish freshness estimation using eye image processing under white and UV lightings

    Science.gov (United States)

    Kanamori, Katsuhiro; Shirataki, Yuri; Liao, Qiuhong; Ogawa, Yuichi; Suzuki, Tetsuhito; Kondo, Naoshi

    2017-05-01

    A non-destructive method of estimating the freshness of fish is required for appropriate price setting and food safety. In particular, for determining the possibility of eating raw fish (sashimi), freshness estimation is critical. We studied such an estimation method by capturing images of fish eyes and performing image processing using the temporal changes of the luminance of pupil and iris. To detect subtle non-visible changes of these features, we used UV (375 nm) light illumination in addition to visible white light illumination. Polarization and two-channel LED techniques were used to remove strong specular reflection from the cornea of the eye and from clear-plastic wrap used to cover the fish to maintain humidity. Pupil and iris regions were automatically detected separately by image processing after the specular reflection removal process, and two types of eye contrast were defined as the ratio of mean and median pixel values of each region. Experiments using 16 Japanese dace (Tribolodon hakonensis) at 23° and 85% humidity for 24 hours were performed. The eye contrast of raw fish increase non-linearly in the initial period and then decreased; however, that of frozen-thawed fish decreased linearly throughout 24 hours, regardless of the lighting. Interestingly, the eye contrast using UV light showed a higher correlation with time than that using white light only in the case of raw fish within the early 6- hour period postmortem. These results show the possibility of estimating fish freshness in the initial stage when fish are eaten raw using white and UV lightings.

  9. Fish biodiversity of the Gabcikovo waterworks

    International Nuclear Information System (INIS)

    Kirka, A.

    1997-01-01

    The historical full list of fish species of the Danube between mouth of the Morava and Ipel rivers had been prepared through decades. It consisted of 66-69 species, which never appear here all at the same time. After 1971, since the Iron Gate on the Yugoslavia-Romania border had been put in function the migration of the big acipenserids was fully stopped. On the other side introduction of new species of fish continuously increased. However, the number of original species consisted of 57 species. In the Danube the occurrence of 45 species from 50 and in the Slovak side arms system 31 species from 56 species were confirmed since 1992 after damming of the Danube. The new full list of species will be achieved only gradually and no species occurring before the damming will be absent. Up to the present time there are no evidence about extinction of any species. In opposite, there is no doubt, that the old - new species like trouts, danube salmon and others are occurring now again in the main channel of the river namely. New micro-habitats as rocky chutes and submerge weirs have created very convenient living conditions together with very reach sources of food (gammarids) and clear substrate on depositing their eggs when spawning. The Cunovo rocky chute is fully inhabited with common rheofils like: trouts, barb, chub, dace, burbot, and with rare and by law protected: bulkhead, streber, zingel, and and long whiskered gudgeon which during last 50 years was found only three times at the Slovak-Hungarian stretch of the Danube river. After finishing the Danube - Main - Rhine canal, the Black Sea and the Atlantic systems have been connected. Despite that the ship locks are considered top be insurmountable barriers for fish, some experts, believe in equalization of the species potentials of fish of these systems within next 50 years. (author)

  10. RARE COMPONENT OF THE FISH FAUNA OF THE 'SULINSKY' NATIONAL LANDSCAPE RESERVE

    Directory of Open Access Journals (Sweden)

    N. Ja. Rudik-Leuska

    2014-06-01

    authorities should focus attention on their protection and restoration of abundance. Keywords: Sulinsky Reserve, Sula Bay, conservation lists, sterlet (Acipenser ruthenus L., Crucian carp (Carassius carassius L., Common dace (Leuciscus leuciscus L., Wels catfish (Silurus glanis L., Asp (Aspius aspius L., Bitterling (Rhodeus sericeus Pall., Spined loach (Cobitis taenia L..

  11. Variation in fish mercury concentrations in streams of the Adirondack region, New York: A simplified screening approach using chemical metrics

    Science.gov (United States)

    Burns, Douglas A.; Riva-Murray, Karen

    2018-01-01

    Simple screening approaches for the neurotoxicant methylmercury (MeHg) in aquatic ecosystems may be helpful in risk assessments of natural resources. We explored the development of such an approach in the Adirondack Mountains of New York, USA, a region with high levels of MeHg bioaccumulation. Thirty-six perennial streams broadly representative of 1st and 2nd order streams in the region were sampled during summer low flow and analyzed for several solutes and for Hg concentrations in fish. Several landscape and chemical metrics that are typically strongly related to MeHg concentrations in aquatic biota were explored for strength of association with fish Hg concentrations. Data analyses were based on site mean length-normalized and standardized Hg concentrations (assumed to be dominantly MeHg) in whole juvenile and adult Brook Trout Salvelinus fontinalis, Creek Chub Semotilus atromaculatus, Blacknose Dace Rhinichthys atratulus, and Central Mudminnow Umbra limi, as well as on multi-species z-scores. Surprisingly, none of the landscape metrics was related significantly to regional variation in fish Hg concentrations or to z-scores across the study streams. In contrast, several chemical metrics including dissolved organic carbon (DOC) concentrations, sulfate concentrations (SO42−), pH, ultra-violet absorbance (UV254), and specific ultra-violet absorbance were significantly related to regional variation in fish Hg concentrations. A cluster analysis based on DOC, SO42−, and pH identified three distinct groups of streams: (1) high DOC, acidic streams, (2) moderate DOC, slightly acidic streams, and (3) low DOC circum-neutral streams with relatively high SO42−. Preliminary analysis indicated no significant difference in fish Hg z-scores between the moderate and high DOC groups, so these were combined for further analysis. The resulting two groups showed strong differences (p 6.9 mg/L, SO42− 0.31 cm−1 were tested as thresholds to identify Adirondack

  12. Abandoned mine drainage in the Swatara Creek Basin, southern anthracite coalfield, Pennsylvania, USA: 1. stream quality trends coinciding with the return of fish

    Science.gov (United States)

    Cravotta, Charles A.; Brightbill, Robin A.; Langland, Michael J.

    2010-01-01

    Acidic mine drainage (AMD) from legacy anthracite mines has contaminated Swatara Creek in eastern Pennsylvania. Intermittently collected base-flow data for 1959–1986 indicate that fish were absent immediately downstream from the mined area where pH ranged from 3.5 to 7.2 and concentrations of sulfate, dissolved iron, and dissolved aluminum were as high as 250, 2.0, and 4.7 mg/L, respectively. However, in the 1990s, fish returned to upper Swatara Creek, coinciding with the implementation of AMD treatment (limestone drains, limestone diversion wells, limestone sand, constructed wetlands) in the watershed. During 1996–2006, as many as 25 species of fish were identified in the reach downstream from the mined area, with base-flow pH from 5.8 to 7.6 and concentrations of sulfate, dissolved iron, and dissolved aluminum as high as 120, 1.2, and 0.43 mg/L, respectively. Several of the fish taxa are intolerant of pollution and low pH, such as river chub (Nocomis icropogon) and longnose dace (Rhinichthys cataractae). Cold-water species such as brook trout (Salvelinus fontinalis) and warm-water species such as rock bass (Ambloplites rupestris) varied in predominance depending on stream flow and stream temperature. Storm flow data for 1996–2007 indicated pH, alkalinity, and sulfate concentrations decreased as the stream flow and associated storm-runoff component increased, whereas iron and other metal concentrations were poorly correlated with stream flow because of hysteresis effects (greater metal concentrations during rising stage than falling stage). Prior to 1999, pH\\5.0 was recorded during several storm events; however, since the implementation of AMD treatments, pH has been maintained near neutral. Flow-adjusted trends for1997–2006 indicated significant increases in calcium; decreases in hydrogen ion, dissolved aluminum, dissolved and total manganese, and total iron; and no change in sulfate or dissolved iron in Swatara Creek immediately downstream from the

  13. Mercury in fishes from 21 national parks in the Western United States: inter- and intra-park variation in concentrations and ecological risk

    Science.gov (United States)

    Eagles-Smith, Collin A.; Willacker, James J.; Flanagan Pritz, Colleen M.

    2014-01-01

    of fish sampled were above a benchmark for risk to highly sensitive avian consumers (90 ng/g ww), and THg concentrations in 68 percent of fish sampled were above exposure levels recommended by the Great Lakes Advisory Group (50 ng/g ww) for unlimited consumption by humans. Of the fish assessed for risk to human consumers (that is, species that are large enough to be consumed by recreational or subsistence anglers), only one individual fish from Yosemite National Park had a muscle Hg concentration exceeding the benchmark (950 ng/g ww) at which no human consumption is advised. Zion, Capital Reef, Wrangell-St. Elias, and Lake Clark National Parks all contained sites in which most fish exceeded benchmarks for the protection of human and wildlife health. This finding is particularly concerning in Zion and Capitol Reef National Parks because the fish from these parks were speckled dace, a small, invertebrate-feeding species, yet their Hg concentrations were as high or higher than those in the largest, long-lived predatory species, such as lake trout. Future targeted research and monitoring across park habitats would help identify patterns of Hg distribution across the landscape and facilitate management decisions aimed at reducing the ecological risk posed by Hg contamination in sensitive ecosystems protected by the National Park Service.

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

    Science.gov (United States)

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

    2010-01-01

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

  15. Instream flow assessment of streams draining the Arbuckle-Simpson Aquifer

    Science.gov (United States)

    Seilheimer, Titus S.; Fisher, William L.

    2008-01-01

    The availability of high quality water is critical to both humans and ecosystems. A recent proposal was made by rapidly expanding municipalities in central Oklahoma to begin transferring groundwater from the Arbuckle-Simpson aquifer, a sensitive sole-source aquifer in south-central Oklahoma. Concerned citizens and municipalities living on and getting their drinking water from the Arbuckle-Simpson lobbied the legislature to pass a temporary moratorium on groundwater transfer to allow for a comprehensive study of the aquifer and its ecosystems. We conducted an instream flow assessment using Physical Habitat Simulation (PHABSIM) on springs and streams with four spring-dependent species: two minnows, southern redbelly dace (Phoxinus erthyrogaster) and redspot chub (Nocomis asper); and two darters, least darter (Etheostoma microperca) and orangethroat darter (Etheostoma spectabile). Spring habitats are unique compared to other river habitats because they have constant flow and temperature, small and isolated habitat patches, and a general lack of predators. Our study sites included two spring-fed streams, one larger stream with high groundwater inputs, and a river with both groundwater and surface water inputs that is adjacent to the small spring-fed streams. These habitats meet the criteria for groundwater dependent ecosystems because they would not exist without the surface expression of groundwater. A total of 99 transects in all four sites were surveyed for channel elevation, and three sets of water surface elevation and water velocity were measured. Habitat suitability criteria were derived for the species at each site using nonparametric confidence limits based on underwater observations made by snorkelers. Simulations of flow were focused on declines in discharge, which is the expected effect of the proposed groundwater diversion. Our results show that only a small proportion of the total available area in each habitat is considered to be preferred habitat

  16. Radioecological zoning of territories of carrying out of underground nuclear explosions in conditions of Yakutia

    International Nuclear Information System (INIS)

    Yakovleva, V.D.; Stepanov, V.E.

    2005-01-01

    raised divisible by two (from 16 μR/h); in a soil - vegetative are registered artificial radionuclides 3 listed above groups; are area activity for cesium - 137 makes from 16.3 kBq/m 2 (0.4 Ci/km 2 ) (16-fold excess of a level of global cesium - 137) and more, for americium - 241 - from 0.08 kBq/m 2 (2.1 mCi/km 2 ) (8-fold excess of a level of global americium-241) and more. 3. The buffer zone is defined to attributes: a) the vegetative cover is not damaged; the scale - background corresponds natural; the soil - vegetative cover contains cesium -137 and americium - 241, area which activity makes from 3.2 kBq/m 2 and 31.3 Bq/m 2 accordingly (3-fold increase in background levels), but in some daces is not observed precise excess above background in that case the raised (increased) maintenance(contents) of cesium - 137 in lichens (Cadalene stellaris, Cladina rangiferina from 170 Bq/kg, Aulacomnium from 120 Bq/kg) and bushes (Betula exilis from 4.5 Bk/kg) is found out. 4. Area the maintenance (contents) of cesium - 137 and americium - 241 in a soil - vegetative cover of a zone of global radioactive losses makes from 0.8 up to 1.9 kBq/m 2 and from 9.2 up to 11.2 Bk/m 2 accordingly. Concentration of cesium - 137 in lichens (Cladina stellaris, Cladina rangiferina, Aulacomnium varies within the limits of 90 Bq/kg), in bushes (Betula exilis within the limits of 2 Bq/kg)

  17. Selenium in ecosystems within the mountaintop coal mining and valley-fill region of southern West Virginia-assessment and ecosystem-scale modeling

    Science.gov (United States)

    Presser, Theresa S.

    2013-01-01

    Coal and associated waste rock are among environmental selenium (Se) sources that have the potential to affect reproduction in fish and aquatic birds. Ecosystems of southern West Virginia that are affected by drainage from mountaintop coal mines and valleys filled with waste rock in the Coal, Gauley, and Lower Guyandotte watersheds were assessed during 2010 and 2011. Sampling data from earlier studies in these watersheds (for example, Upper Mud River Reservoir) and other mining-affected watersheds also are included to assess additional hydrologic settings and food webs for comparison. Basin schematics give a comprehensive view of sampled species and Se concentration data specific to location and date. Food-web diagrams document the progression of Se trophic transfer across suspended particulate material, invertebrates, and fish for each site to serve as the basis for developing an ecosystem-scale model to predict Se exposure within the hydrologic conditions and food webs of southern West Virginia. This approach integrates a site-specific predator’s dietary exposure pathway into modeling to ensure an adequate link to Se toxicity and, thus, to species vulnerability. Site-specific fish abundance and richness data in streams documented various species of chub, shiner, dace, darters, bass, minnow, sunfish, sucker, catfish, and central stoneroller (Campostoma anomalum), mottled sculpin (Cottus bairdii), and least brook lamprey (Lampetra aepyptera). However, Se assessment species for streams, and hence, model species for streams, were limited to creek chub (Semotilus atromaculatus) and central stoneroller. Both of these species of fish are generally considered to have a high tolerance for environmental stress based on traditional comparative fish community assessment, with creek chub being present at all sites. Aquatic insects (mayfly, caddisfly, stonefly, dobsonfly, chironomid) were the main invertebrates sampled in streams. Collection of suspended particulate material