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Sample records for european eel anguilla

  1. Simulated migration of European eel (Anguilla anguilla, Linnaeus 1758)

    NARCIS (Netherlands)

    Ginneken, van V.J.T.

    2006-01-01

    The European eel ( Anguillaanguilla L.) is a catadromic fish species with its spawning grounds thousands of kilometers away in the ocean, possibly theSargasso Sea. The objective of this study was to elucidate this oceanic phase of migration

  2. Fecundity of migrating European eel (Anguilla anguilla from Polish waters

    Directory of Open Access Journals (Sweden)

    Marta Dębowska

    2015-09-01

    Full Text Available This study demonstrated that individual fecundity of 34 migrating European female eels Anguilla anguilla increases linearly with body weight (BW and total length (TL. The total individual fecundity of fish from 560 to 1960 g BW was between 981 x 103 and 6320 x 103 eggs, respectively. The mean relative individual fecundity equalled 2415 x 103 (± 524 x 103 per kg BW. The values of this parameter ranged from 1753 x 103 to 3224.5 x 103 kg–1. Based on the results, it might be suggested that A. anguilla has lower total individual fecundity than New Zealand longfin eel (Anguilla dieffenbachii, American eel (Anguilla rostrata and Japanese eel (Anguilla japonica although it has one of the highest fecundity values per kg BW. Total fecundity was strongly depended from fat level in muscle (R2 = 0.9523 and ovary (R2 = 0.9531 as well as level of DHA content in ovary (R2 = 0.8967 and muscle (R2 = 0.6274 (N=10. There were no important relationship between total fecundity and protein level as well as in muscle and ovary

  3. Toxic textile dyes accumulate in wild European eel Anguilla anguilla.

    Science.gov (United States)

    Belpaire, Claude; Reyns, Tim; Geeraerts, Caroline; Van Loco, Joris

    2015-11-01

    Dyes are used to stain inks, paints, textile, paper, leather and household products. They are omnipresent, some are toxic and may threaten our environment, especially aquatic ecosystems. The presence of residues of sixteen dyes (triarylmethanes, xanthenes, phenothiazines and phenoxazines) and their metabolites was analyzed in muscle tissue samples of individual yellow-phased European eels (Anguilla anguilla) from 91 locations in Belgian rivers, canals and lakes sampled between 2000 and 2009 using ultra performance liquid chromatography-tandem mass spectrometry. Eel was contaminated by dyes in 77% of the sites. Malachite Green, Crystal Violet and Brilliant Green were present in 25-58% of the samples. Dye occurrence was related to the distribution of textile and dye production industries. This field study is the first large-scale survey to document the occurrence of artificial dyes in wildlife. Considering the annual amounts of dyes produced worldwide and the unintentional spillage during their use, our observations warrant additional research in other parts of the world. The presence of these highly toxic dyes in the European eel may form an additional threat to this critically endangered species. The contaminated eels should be considered as not suitable for consumption. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Endocrine profiles during silvering of the European eel (Anguilla anguilla L.) living in saltwater

    NARCIS (Netherlands)

    Ginneken, van V.; Durif, C.; Dufour, C.; Sbaihi, M.; Boot, R.; Noorlander, K.; Doornbos, J.; Murk, A.J.; Thillart, van den G.

    2007-01-01

    The transformation of yellow eel into silver eel is called 'silvering', and takes place prior to migration. This is the first study to provide hormonal profiles of European eel (Anguilla anguilla L.) during silvering. This transformation occurs in association with hormonal surges of testosterone (T)

  5. Viral diseases of wild and farmed European eel Anguilla anguilla with particular reference to the Netherlands

    NARCIS (Netherlands)

    Beurden, van S.J.; Engelsma, M.Y.; Roozenburg, I.; Voorbergen-Laarman, H.A.; Tulden, van P.W.; Kerkhoff, S.; Nieuwstadt, A.; Davidse, A.; Haenen, O.L.M.

    2012-01-01

    Diseases are an important cause of losses and decreased production rates in freshwater eel farming, and have been suggested to play a contributory role in the worldwide decline in wild freshwater eel stocks. Three commonly detected pathogenic viruses of European eel Anguilla anguilla are the

  6. Standardization of fertilization protocols for the European eel, Anguilla anguilla

    DEFF Research Database (Denmark)

    Butts, Ian; Sørensen, Sune Riis; Politis, Sebastian Nikitas

    2014-01-01

    Standardization of artificial fertilization protocols for the European eel, Anguilla anguilla, is a prerequisite for optimizing the use of available gametes in hatchery facilities and for conserving sperm from high quality males, which is either cryopreserved or in living gene banks. The objectives...... of this research were to provide a rapid, accurate and precise method to quantify sperm density by examining the relationship between sperm density and absorbance by use of a spectrophotometer, determine the optimal number of sperm required to fertilize eggs in a controlled setting, and explore how long eggs...... are receptive to fertilization post-stripping. Mean sperm density and absorbance at 350nm were 1.54e+10±4.95e+9sperm/mL and 1.91±0.22nm, respectively. Regression analysis demonstrated a highly significant positive relationship between sperm density and absorbance using a spectrophotometer at 350nm (R2=0.94, p

  7. Microsatellite variation between Japanese eel ( Anguilla japonica) and European eel ( Anguilla anguilla)

    Science.gov (United States)

    Liang, Jun; Li, Daoji; Lu, Liqiong

    2005-12-01

    Allelic variation in a total of 7 microsatellites was examined between elvers of freshwater eels ( Anguilla japonica and Anguilla anguilla). The number of alleles at these loci ranged from 8 to 26. A single test of each locus revealed significant deficits of heterozygotes ( PHardy-Weinberg equilibrium (HWE) was found for all loci within four subpopulations of A. japonica, which opposes the panmixia hypothesis of Schmidt. Also exact tests of population differentiation based on allelic frequency distribution disagree the hypothesis of random distribution of individuals among populations. Population structure among four populations of A. japonica was revealed with F ST value of 0.009 8 ( P=0.00048; 10 000 iteration). Pairwise matrixes of F ST and R ST showed a significant difference between two distantly related species— A. japonica and A. anguilla. Divergent time of the two species calculated by Goldstein method is over 2 million years. The results may challenge the Schmidt's theory about the distribution of freshwater eels.

  8. Molecular approaches related to the European eel (Anguilla anguilla) reproductive process

    OpenAIRE

    Morini, Marina Ange Marie

    2016-01-01

    [EN] The European eel (Anguilla anguilla, L., 1758) population is in dramatic decline, so much so that this species has been listed as "Critically Endangered" on the Red List of Threatened Species, by the International Union for Conservation of Nature (IUCN). The European eel has a complex life cycle, with sexual maturation blocked in the absence of the reproductive oceanic migration, and an inability to mature in captivity without the administration of hormonal treatments. Even though experi...

  9. The European Eel Anguilla anguilla (Pisces, Anguillidae. Native or Alien in the Black Sea?

    Directory of Open Access Journals (Sweden)

    Apostolos I. Apostolou

    2013-12-01

    Full Text Available In 2006 the Scientific, Technical and Economic Committee for Fisheries (STEFC of EU suggested the Black Sea region should be excluded from the list of natural areas, where the European eel (Anguilla anguilla is distributed. The basic conception of this idea was that the eels caught in the Black Sea region represent escaped specimens from fish farming in some Danubian countries. This article illustrates an effort to be given an indirect answer on the question if Black Sea is the end of natural distribution of European eel. The species is present but never been abundant in the region and do not represent an object of commercial fishing.

  10. Enteric neuroplasticity in seawater-adapted European eel (Anguilla anguilla)

    Science.gov (United States)

    Sorteni, C; Clavenzani, P; De Giorgio, R; Portnoy, O; Sirri, R; Mordenti, O; Di Biase, A; Parmeggiani, A; Menconi, V; Chiocchetti, R

    2014-01-01

    European eels live most of their lives in freshwater until spawning migration to the Sargasso Sea. During seawater adaptation, eels modify their physiology, and their digestive system adapts to the new environment, drinking salt water to compensate for the continuous water loss. In that period, eels stop feeding until spawning. Thus, the eel represents a unique model to understand the adaptive changes of the enteric nervous system (ENS) to modified salinity and starvation. To this purpose, we assessed and compared the enteric neuronal density in the cranial portion of the intestine of freshwater eels (control), lagoon eels captured in brackish water before their migration to the Sargasso Sea (T0), and starved seawater eels hormonally induced to sexual maturity (T18; 18 weeks of starvation and treatment with standardized carp pituitary extract). Furthermore, we analyzed the modification of intestinal neuronal density of hormonally untreated eels during prolonged starvation (10 weeks) in seawater and freshwater. The density of myenteric (MP) and submucosal plexus (SMP) HuC/D-immunoreactive (Hu-IR) neurons was assessed in wholemount preparations and cryosections. The number of MP and SMP HuC/D-IR neurons progressively increased from the freshwater to the salty water habitat (control > T0 > T18; P neuroplasticity as indicated by the increasing number of HuC/D-IR MP and SMP neurons, a mechanism likely contributing to maintaining the body homeostasis of this fish in extreme conditions. PMID:24433383

  11. A spatial assessment model for European eel (Anguilla anguilla in a delta, The Netherlands

    Directory of Open Access Journals (Sweden)

    Van De Wolfshaar K.E.

    2013-12-01

    Full Text Available Given the poor status of the European eel (Anguilla anguilla population, good assessments are essential to optimise recovery measures. Quantifying eel stock size is challenging given the fractal nature of the distribution of eels, particularly in The Netherlands with its dense interconnected network of drainage ditches, rivers and lakes. Dynamic demographic models as used by others are inappropriate in this delta with a demand for regional information on stock size. We therefore estimated the standing eel stock biomass for all freshwater water bodies, using fish monitoring data collected under the Water Framework Directive and a static GIS approach. Density data were extrapolated to total biomass estimates using GIS data concerning water type, surface area and bank length, and biological parameters obtained from biological data. The analysis yielded density and biomass estimates of the total eel and silver eel stock, with most silver eel biomass being confined to a few coastal regions. The main conclusion is that over half of the Dutch eel biomass is found in the small, regionally managed waters, revealing a crude underestimation of the eel biomass in the 2009 Dutch Eel Management Plan. The silver eel biomass estimate presented here is two to three times higher than previous estimates. Providing spatial information on eel biomass will aid in prioritising management measures to reduce anthropogenic mortality.

  12. The migration behaviour of European silver eels (Anguilla anguilla) released in open ocean conditions

    DEFF Research Database (Denmark)

    Wysujack, K.; Westerberg, H.; Aarestrup, Kim

    2015-01-01

    Despite some recent progress, there are still large gaps of knowledge about migration routes and behaviour of European eels, Anguilla anguilla, during their long-distance oceanic migration. To achieve a better understanding of the migration behaviour, 28 large female silver eels were equipped...... with pop-up satellite transmitters and released at three different locations in the north-eastern Atlantic Ocean and in the Sargasso Sea. The study covers tracking periods between 7 and 92 days. The distance between release point and estimated pop-up position ranged from 40 to 1000 km, the mean minimum...

  13. Reproductive potential of silver European eels (Anguilla anguilla migrating from Vistonis Lake (Northern Aegean Sea, Greece

    Directory of Open Access Journals (Sweden)

    R. MACNAMARA

    2014-06-01

    Full Text Available The European eel (Anguilla anguilla, once abundant throughout much of Europe and North Africa, has recently been classified as critically endangered. Information on its biology from the eastern Mediterranean is lacking, especially in relation to spawner quality. Therefore, silver eels were sampled during their seaward spawning migration from Vistonis Lake in Greece. Characteristics linked to reproductive output and success (i.e. body size and condition, sex ratio, silvering, Anguillicola crassus infection, fecundity and oocyte diameter were examined. The lake produced large (687–1138 mm, exclusively female silver eels, 61.7% of which were infected by A. crassus. Silver eel fecundity, the first estimates from the southern part of the species range, was positively related to body length (R2 = 0.693; P < 0.001 and body weight (R2 = 0.731; P < 0.001. Fecundity did not differ between A. crassus infected and uninfected silver eels, but Greek silver eels were significantly more fecund than those in north-west Europe. The reproductive potential of Vistonis Lake silver eels and their contribution to the A. anguilla spawning stock is discussed.

  14. Impairment of lipid storage by cadmium in the European eel (Anguilla anguilla)

    Energy Technology Data Exchange (ETDEWEB)

    Pierron, Fabien [UMR CNRS 5805 EPOC, Team GEMA, Universite Bordeaux 1 and CNRS, Place du Dr Peyneau, 33120 Arcachon (France); Baudrimont, Magalie [UMR CNRS 5805 EPOC, Team GEMA, Universite Bordeaux 1 and CNRS, Place du Dr Peyneau, 33120 Arcachon (France)]. E-mail: m.baudrimont@epoc.u-bordeaux1.fr; Bossy, Angelique [UMR CNRS 5805 EPOC, Team GEMA, Universite Bordeaux 1 and CNRS, Place du Dr Peyneau, 33120 Arcachon (France); Bourdineaud, Jean-Paul [UMR CNRS 5805 EPOC, Team GEMA, Universite Bordeaux 1 and CNRS, Place du Dr Peyneau, 33120 Arcachon (France); Brethes, Daniel [IBGC, UMR CNRS 5095, Universite Bordeaux 2 and CNRS, 1, rue Camille Saint Saens, 33077 Bordeaux Cedex (France); Elie, Pierre [Cemagref, Unite Ecosystemes Estuariens et Poissons Migrateurs Amphihalins, U.R. EPBX, Cemagref, 50 Avenue de Verdun, 33612 Cestas (France); Massabuau, Jean-Charles [UMR CNRS 5805 EPOC, Team GEMA, Universite Bordeaux 1 and CNRS, Place du Dr Peyneau, 33120 Arcachon (France)

    2007-03-10

    Because European silver eels (Anguilla anguilla) fast during their reproductive migration to the Sargasso Sea, the successful completion of their unusual life cycle depends on quantity of lipids stored beforehand. These lipids are mainly accumulated during the growth phase stage of the animals, called yellow eel, as triglycerides in muscle. They are then catabolized to provide sufficient energy to enable migration, gonad maturation and spawning. In the laboratory, we investigated the possible impact of cadmium on the lipid storage efficiency of yellow eels in order to evaluate the possible contribution of this pollutant to the reported decline of European eel populations. Eels were exposed to dissolved cadmium at nominal concentrations of 0 and 5 {mu}g L{sup -1} for 1 month. Cd toxicity was then examined by studying the activity and expression level of several enzymes involved in liver lipolysis and lipogenesis and by determining lipid content in muscle. Contaminated eels showed a lower body weight growth with a lower efficiency of lipid storage compared to controls. Using two complementary approaches, genetic and enzymatic, it was possible to conclude that this impairment is mainly explained by an increased utilisation of triglycerides since cadmium contamination did not trigger a reduced fatty acid synthesis. These observations suggest an increased fat consumption in presence of cadmium, which could compromise successful reproduction.

  15. Abundance of specific mRNA transcripts impacts hatching success in European eel, Anguilla anguilla L

    DEFF Research Database (Denmark)

    Rozenfeld, Christoffer; Butts, Ian A.E.; Tomkiewicz, Jonna

    2016-01-01

    MaternalmRNA governs earlyembryonic development in fish and variation in abundance of maternal transcripts may contribute to variation in embryonic survival and hatch success in European eel, Anguilla anguilla. Previous studies have shown that quantities of the maternal gene products β-tubulin, i......MaternalmRNA governs earlyembryonic development in fish and variation in abundance of maternal transcripts may contribute to variation in embryonic survival and hatch success in European eel, Anguilla anguilla. Previous studies have shown that quantities of the maternal gene products β......-tubulin, insulin-like growth factor 2 (igf2), nucleoplasmin (npm2), prohibitin 2 (phb2), phosphatidylinositol glycan biosynthesis class F protein 5 (pigf5), and carnitine O-palmitoyltransferase liver isoform-like 1 (cpt1) are associated with embryonic developmental competence in other teleosts. Here, the relations...... between relative mRNA abundance of these genes in eggs and/or embryos and egg quality, was studied and analyzed. We compared egg quality of the two groups: i) batches with hatching and ii) batches with no hatching. Results showed no significant differences in relative mRNA abundance between the hatch...

  16. Tolerance of chronic hypercapnia by the European eel Anguilla anguilla

    DEFF Research Database (Denmark)

    McKenzie, D J; Piccolella, M; Dalla Valle, A Z

    2003-01-01

    as normocapnic animals. Hypercapnia had no effect on such indicators of stress as plasma catecholamine or cortisol levels, plasma osmolality or standard metabolic rate. Furthermore, although Ca(O)(2) was reduced by approximately 50% at the highest P(CO)(2), there was no effect of hypercapnia on the eels......' tolerance of hypoxia, aerobic metabolic scope or sustained swimming performance. The results indicate that, at the levels tested, chronic hypercapnia was not a physiological stress for the eel, which can tolerate extracellular acidosis and extremely low Cl(-) levels while compensating tissue intracellular p......H, and which can meet the O(2) requirements of routine and active metabolism despite profound hypoxaemia....

  17. Reflex bradycardia does not influence oxygen consumption during hypoxia in the European eel (Anguilla anguilla)

    DEFF Research Database (Denmark)

    Iversen, Nina Kerting; McKenzie, David; Malte, H.

    2010-01-01

    the bradycardia on oxygen consumption (MO2), standard metabolic rate (SMR) and the critical oxygen partial pressure for regulation of SMR in hypoxia (Pcrit) in European eels Anguilla anguilla (mean ± SEM mass 528 ± 36 g; n = 14). Eels were instrumented with a Transonic flow probe around the ventral aorta......Most teleost fish reduce heart rate when exposed to acute hypoxia. This hypoxic bradycardia has been characterised for many fish species, but it remains uncertain whether this reflex contributes to the maintenance of oxygen uptake in hypoxia. Here we describe the effects of inhibiting...... to measure cardiac output (Q) and heart rate (f H). MO2 was then measured by intermittent closed respirometry during sequential exposure to various levels of increasing hypoxia, to determine Pcrit. Each fish was studied before and after abolition of reflex bradycardia by intraperitoneal injection...

  18. Effects of salinity and sea salt type on egg activation, fertilization, buoyancy and early embryology of European eel, Anguilla anguilla

    DEFF Research Database (Denmark)

    Sørensen, Sune Riis; Butts, Ian; Munk, Peter

    2016-01-01

    Improper activation and swelling of in vitro produced eggs of European eel, Anguilla anguilla, has been shown to negatively affect embryonic development and hatching. We investigated this phenomenon by examining the effects of salinity and sea salt type on egg dimensions, cell cleavage patterns a...

  19. Movement patterns of seaward migrating European eel (Anguilla anguilla) at a complex of riverine barriers: implications for conservation

    DEFF Research Database (Denmark)

    Piper, Adam T.; Svendsen, Jon Christian; Wright, Rosalind M.

    2017-01-01

    , this is currently lacking for many species. Employing high-resolution positioning telemetry, this study examined movements of downstream migrating adult European eel, Anguilla anguilla, as they encountered a complex of water control structures in one location on the River Stour, southern England. The distribution...

  20. Tolerance of hypercapnic acidosis by the European eel, Anguilla anguilla

    DEFF Research Database (Denmark)

    McKenzie, DJ; Dalla Valle, AZ; Steffensen, JF

    2000-01-01

    Eels reared intensively in recirculated water can experience chronic hypercapnia from accumulation of metabolic CO2, with water CO2 partial pressures (Pw,CO2) exceeding 30 mmHg, far above that hitherto considered normal for fish (1 to 3 mmHg). The effects on eels of acute and chronic hypercapnia...... were investigated. Eels (n = 6) were anaesthetised (0.05 % MS-222 in water), cannulated in the dorsal aorta for withdrawal of blood samples and in the operculum for measurement of gill ventilation rate (fG) and pressure amplitude (POP). A flow cuff placed on the ventral aorta measured cardiac output.......5 ± 2.2 vol%, significantly lower than in the control animals, where pHa was 7.89 ± 0.04 and ca,O2 11.6 ± 1.5 vol%. Exercise performance was studied in a swimming respirometer. Stepwise increases in swimming speed caused similar, exponential increases in O2 uptake in all groups, with no differences...

  1. Survival and progression rates of large European silver eel Anguilla anguilla in late freshwater and early marine phases

    DEFF Research Database (Denmark)

    Aarestrup, Kim; Thorstad, Eva B.; Koed, Anders

    2010-01-01

    The population of European silver eel Anguilla anguilla has declined tremendously in the last decades. The cause of this decline is unknown, and it is necessary to investigate the migratory behaviour and survival rates of silver eels during the reproductive migration in order to understand...... was high in fresh water. However, 60% of eels were lost in the inner and outer fjord, supporting the hypothesis that mortality is large in the early phase of the marine migration and that fishing may be a major cause of mortality of silver eels. There was no indication that the slowest-migrating...... if the decline is related to factors acting during that migration. We estimated survival and progression rates of European silver eel migrating in the lower part of the River Gudenaa and during the first phase of the marine migration in the Randers Fjord in Denmark. Fifty migrating silver eel (total body length...

  2. Temperature effects on gene expression and morphological development of European eel, Anguilla anguilla larvae

    DEFF Research Database (Denmark)

    Politis, Sebastian Nikitas; Mazurais, David; Servili, Arianna

    2017-01-01

    to first-feeding, and the linked expression of targeted genes [heat shock proteins (hsp), growth hormone (gh) and insulin-like growth factors (igf)] associated to larval performance of European eel, Anguilla anguilla. Temperature effects on larval morphology and gene expression were investigated throughout......Temperature is important for optimization of rearing conditions in aquaculture, especially during the critical early life history stages of fish. Here, we experimentally investigated the impact of temperature (16, 18, 20, 22 and 24°C) on thermally induced phenotypic variability, from larval hatch...... affected by temperature. In real time, increasing temperature from 16 to 22°C accelerated larval development, while larval gene expression patterns (hsp70, hsp90, gh and igf-1) were delayed at cold temperatures (16°C) or accelerated at warm temperatures (20-22°C). All targeted genes (hsp70, hsp90, gh, igf...

  3. Effects of dietary fatty acid composition on metabolic rate and responses to hypoxia in the European eel (Anguilla anguilla)

    DEFF Research Database (Denmark)

    McKenzie, D.J.; Piraccini, G.; Piccolella, M.

    2000-01-01

    European eels (Anguilla anguilla, L.) were fed on a commercial diet supplemented either with 15% by dry feed weight of menhaden oil (MO), an oil rich in highly unsaturated fatty acids of the n-3 series (n-3 HUFA), or with 15% by dry feed weight of coconut oil (CO), an oil composed primarily...... of saturated fatty acids (SFA). Following 90 days of feeding, the mean final masses of eels fed the two different oil supplements were similar, and higher than the mean final mass of a group fed the commercial diet alone. The diets created two distinct phenotypes of eels, distinguished by the fatty acid (FA...

  4. Chemical elements in the muscle tissues of European eel (Anguilla anguilla) from selected lakes in Latvia.

    Science.gov (United States)

    Rudovica, Vita; Bartkevics, Vadims

    2015-10-01

    Fish is a significant source of essential nutrients, as well as toxic elements in the human diet. Concentration of 17 elements was determined in muscles of eels (Anguilla anguilla) collected from five fishing lakes in the territory of Latvia. The concentration of main elements determined in muscle tissues varied within the following ranges: for Pb, 0.019-0.047; Cd, 0.0051-0.011; Hg, 0.13-0.36; Cu, 0.76-0.92; Zn, 28-42; and As, 0.13-0.23 mg kg(-1) wet weight. A positive correlation was revealed between the concentration of Hg in muscles and fish length in inland lakes. Concentration of metals in muscle tissues of eels from brackish coastal and inland lakes was without statistically significant difference. This research demonstrated that the elemental content of Cd and Pb in muscles of the examined fish was lower than the maximum allowed threshold set by the European Union legislation. Mercury content was over the threshold limit for all the analyzed eels if to compare with the Water Framework Directive Environmental Quality Standards. On other side, only 7% of analyzed fish have indicated values that are over threshold limits for mercury established by the European Union food legislation. The current study contributes to the implementation of Water Framework Directive in Latvia by collection of information necessary for the further protection measures of waters. To our knowledge, this study provides the first data on multielemental bioaccumulation in muscle tissues of European eels collected from fishing lakes of Latvia.

  5. Kinetics of radiolabelled silver uptake and depuration in the gills of rainbow trout (Oncorhynchus mykiss) and European eel (Anguilla anguilla)

    DEFF Research Database (Denmark)

    Wood, C.M.; Grosell, M.; Hogstrand, C.

    2002-01-01

    We examined the influence of speciation on the kinetics of silver uptake and deputation in the gills of two freshwater fish, the rainbow trout (Oncorhynchus mykiss) which has high branchial Na+ and Cl- uptake rates and is relatively sensitive to silver, and the European eel (Anguilla anguilla...... labile than from Ag+ exposures, with 1.6-1.8-fold greater loss rates during the fast phases in both species. Differences in branchial silver uptake between eel and trout correlate well with differences in acute toxicity, but are not as large as differences in ion uptake rates. The complex time-dependent...

  6. Growth observations on European (Anguilla anguilla L. and American (Anguilla rostrata Le Sueur glass eels

    Directory of Open Access Journals (Sweden)

    APPELBAUM S.

    1998-04-01

    (x = 0.167 ± 0.006 g. After 45 days of rearing, the weight differences between the species became insignificant. Except for the different transportation mortalities on arrival, the European and the American eels demonstrated similar mortality rates during the experiment ( 1 2 . 5 % , food conversion rate (2.3 and specific growth rate (0.90 and 0.99 respectively. No parasites or diseases were detected. No differences were observed in general behaviour and feeding between the two species.

  7. Anguillicola crassus (Nematoda, Dracunculoidea) infections of European eel (Anguila anguilla) in the Netherlands : epidemiology, pathogenensis and pathobiology

    NARCIS (Netherlands)

    Haenen, O.L.M.

    1995-01-01


    In the 1980s an eel parasitic nematode, Anguillicola crassus (Nematoda, Dracunculoidea), which infects the swimbladder of European eels ( Anguilla anguilla ) and other freshwater fish species, was introduced into The Netherlands. This thesis

  8. Temperature effects on gene expression and morphological development of European eel, Anguilla anguilla larvae.

    Directory of Open Access Journals (Sweden)

    Sebastian N Politis

    Full Text Available Temperature is important for optimization of rearing conditions in aquaculture, especially during the critical early life history stages of fish. Here, we experimentally investigated the impact of temperature (16, 18, 20, 22 and 24°C on thermally induced phenotypic variability, from larval hatch to first-feeding, and the linked expression of targeted genes [heat shock proteins (hsp, growth hormone (gh and insulin-like growth factors (igf] associated to larval performance of European eel, Anguilla anguilla. Temperature effects on larval morphology and gene expression were investigated throughout early larval development (in real time from 0 to 18 days post hatch and at specific developmental stages (hatch, jaw/teeth formation, and first-feeding. Results showed that hatch success, yolk utilization efficiency, survival, deformities, yolk utilization, and growth rates were all significantly affected by temperature. In real time, increasing temperature from 16 to 22°C accelerated larval development, while larval gene expression patterns (hsp70, hsp90, gh and igf-1 were delayed at cold temperatures (16°C or accelerated at warm temperatures (20-22°C. All targeted genes (hsp70, hsp90, gh, igf-1, igf-2a, igf-2b were differentially expressed during larval development. Moreover, expression of gh was highest at 16°C during the jaw/teeth formation, and the first-feeding developmental stages, while expression of hsp90 was highest at 22°C, suggesting thermal stress. Furthermore, 24°C was shown to be deleterious (resulting in 100% mortality, while 16°C and 22°C (~50 and 90% deformities respectively represent the lower and upper thermal tolerance limits. In conclusion, the high survival, lowest incidence of deformities at hatch, high yolk utilization efficiency, high gh and low hsp expression, suggest 18°C as the optimal temperature for offspring of European eel. Furthermore, our results suggest that the still enigmatic early life history stages of

  9. Metabolites of polycyclic aromatic hydrocarbons (PAHs) in bile as biomarkers of pollution in European eel (Anguilla anguilla) from German rivers.

    Science.gov (United States)

    Nagel, F; Kammann, U; Wagner, C; Hanel, R

    2012-02-01

    In the light of the alarming decline of the European eel (Anguilla anguilla L.) population, there is an urgent need to define ecological indicators for eel habitat quality. Due to an increasing shortage of glass eels available for local stock enhancement, the decision of whether restocking is a valuable management tool to increase high-quality silver eel escapement to the sea needs to be evaluated. Organic contaminants, such as polycyclic aromatic hydrocarbons (PAHs), are among the major threats to fish in their habitat. Therefore, the aim of the investigation presented here was to examine metabolites of PAHs in eel bile as one possible marker for habitat quality. In total, 170 yellow eels were collected in the rivers Rhine, Ems, Weser, Elbe, Havel, Schlei, Eider, Trave, Warnow, Peene, Uecker, and Oder in 2009. PAH metabolites in eel bile were analyzed using high-performance liquid chromatography with fluorescence detection. Metabolites of pyrene and phenanthrene were investigated. Concentrations of PAH metabolites in eel bile varied significantly between several rivers, with the highest mean concentrations of 1-hydroxypyrene and 1-hydroxyphenanthrene in eel bile from the river Trave (2421 and 632 ng/ml). Moreover, huge differences in the ratio of 1-hydroxypyrene to 1-hydroxyphenanthrene, with the highest mean value in eel bile from the river Ems (7.43) and the lowest mean value in eel bile from the river Uecker (0.70), indicate different sources of PAH contamination. A comparative analysis of PAH-metabolite contamination of eels in different river systems is seen as a first step toward a classification of freshwater habitats for restocking purposes.

  10. Accumulation and distribution of platinum and rhodium in the European eel Anguilla anguilla following aqueous exposure to metal salts

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, S.; Baumann, U.; Taraschewski, H.; Sures, B

    2004-01-01

    The platinum group metals (PGM) Pt and Rh are emitted into the environment mainly by catalytic exhaust gas converters of cars and by effluents of hospitals, which use Pt based anti-cancer drugs. However, there is still a lack of information on the availability of these precious metals to the biosphere. As PGM accumulate in sediments of aquatic ecosystems we focused our study on the uptake of the noble metals by European eels, Anguilla anguilla. Therefore, eels were exposed in tap water and humic water containing Pt{sup 4+} and Rh{sup 3+} at a concentration of 170 and 260 {mu}g/l, respectively. After an exposure period of 6 weeks the mean Pt levels in bile, liver, kidney and intestine of the exposed eels ranged between 68 ng/g and 840 ng/g and the mean Rh levels between 35 ng/g and 155 ng/g whereas the PGM levels of the unexposed controls were below the detection limit of 50 ng/g for Pt and 5 ng/g for Rh. Rh was also taken up by gill and spleen. No PGM uptake was found for muscle and blood. The pattern of metal distribution within the eel differed between Pt and Rh and was dependent on the water type. Due to their accumulation capacity for PGM eels are suitable as accumulation indicators to detect PGM pollution in aquatic ecosystems. - Eels are suitable accumulation indicators for platinum group metals in aquatic ecosystems.

  11. Heavy metals and organochlorinated compounds in the European eel (Anguilla anguilla) from the Adour estuary and associated wetlands (France).

    Science.gov (United States)

    Tabouret, H; Bareille, G; Mestrot, A; Caill-Milly, N; Budzinski, H; Peluhet, L; Prouzet, P; Donard, O F X

    2011-05-01

    Heavy metals and organic pollutants were investigated in the Adour estuary (South West France) and associated wetlands using the European eel (Anguilla anguilla) as a bioindicator. Heavy metals (Cu, Cd, Zn, Pb, and Ag) were measured in soft tissue of yellow eels. Mercury (total Hg and MeHg) and organochlorinated compounds (7 PCBs, 11 OCPs) were analysed in muscle. Concentrations in muscle were in agreement with moderately contaminated environments in Europe and were below the norms fixed for eel consumption for heavy metals and OCPs. Analyses of liver showed a higher pressure of Ag and Zn in the downstream estuary than in the freshwater sites whereas Cd was lower in the estuary probably because of the salinity influence. According to quality classes 100% of eels from freshwater sites indicated clean or slightly polluted environments. However, total mercury concentrations were close to the thresholds fixed by the European Community in the downstream estuary, whereas the sum of PCBs was found to be greatly above the fixed value. 100% of the individuals from the estuary were classified in quality classes corresponding to polluted or highly polluted sites. These first results highlight the need of further investigations focused on mercury and PCBs in this area taking the seasonal temperature influence into account for a better understanding of the pollution distribution and the possible threat on the eel population from the Adour basin.

  12. Preliminary results on the biology of the European eel (Anguilla anguilla in the European Southern tip

    Directory of Open Access Journals (Sweden)

    Raquel Moreno-Valcárcel

    2015-10-01

    Full Text Available In the context of the European Eel Recovery Plan, managers need confident biological information based on its own geographical areas. In the specific case of Andalusia (Southern Spain, we are developing a capture-recapture experiment based in the use of PIT-tags in order to obtain information that we lack for the species in the study area. In this communication, we focus on the biology of the species. Firstly, we carried out an ex-situ experiment to check the effect of the PIT-tag on the individuals of the eel. Once we ascertained there were no significant effects in the survival, length, and weight of the marked eels, we proceeded with the study in situ (Guadiaro river. Between October 2014 and July 2015 we captured 1011 eels (539 tagged; 252 recaptured. Approximately 90% of their lengths were between 16-40 cm (minimum 16.3 cm; maximum 67 cm. Eel’s length in March, April and May was significantly lower than those captured in the rest of months, probably because longer eels migrated before spring and only small eels remained in the population. More than 90% of the eels captured in all months were resident, and the higher proportions of migrants were detected in October 2014, November 2014 and July 2015. Mean lengths registered per maturation stage were notably lower than those found in other populations. The growth values showed in this population were higher in autumn (0.195 mm/day than in winter (0.091 mm/day and summer (0.096 mm/day, and residual condition factor showed normal values in comparison with other populations with minimum values in autumn.

  13. A physiologically based toxicokinetic (PBTK) model for moderately hydrophobic organic chemicals in the European eel (Anguilla anguilla)

    Energy Technology Data Exchange (ETDEWEB)

    Brinkmann, Markus [Department of Ecosystem Analysis, Institute for Environmental Research, ABBt — Aachen Biology and Biotechnology, RWTH Aachen University, Aachen (Germany); Freese, Marko; Pohlmann, Jan-Dag; Kammann, Ulrike [Thünen Institute of Fisheries Ecology, Hamburg (Germany); Preuss, Thomas G. [Environmental Biology and Chemodynamics, Institute for Environmental Research, ABBt — Aachen Biology and Biotechnology, RWTH Aachen University, Aachen (Germany); Buchinger, Sebastian; Reifferscheid, Georg [Federal Institute of Hydrology (BFG), Department G3: Biochemistry, Ecotoxicology, Koblenz (Germany); Beiermeister, Anne; Hanel, Reinhold [Thünen Institute of Fisheries Ecology, Hamburg (Germany); Hollert, Henner, E-mail: Henner.hollert@bio5.rwth-aachen.de [Department of Ecosystem Analysis, Institute for Environmental Research, ABBt — Aachen Biology and Biotechnology, RWTH Aachen University, Aachen (Germany); State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing (China); College of Resources and Environmental Science, Chongqing University, Chongqing (China); Key Laboratory of Yangtze Water Environment, Ministry of Education, Tongji University, Shanghai 200092 (China)

    2015-12-01

    The European eel (Anguilla anguilla) is a facultatively catadromous fish species with a complex life cycle. Its current population status is alarming: recruitment has decreased drastically since the 1980s and its stock is still considered to be outside safe biological limits. Although there is no consensus on the reasons for this situation, it is currently thought to have resulted from a combination of different stressors, including anthropogenic contaminants. To deepen our understanding of the processes leading to the accumulation of lipophilic organic contaminants in yellow eels (i.e. the feeding, continental growth stage), we developed a physiologically based toxicokinetic model using our own data and values from the literature. Such models can predict the uptake and distribution of water-borne organic chemicals in the whole fish and in different tissues at any time during exposure. The predictive power of the model was tested against experimental data for six chemicals with n-octanol-water partitioning coefficient (log K{sub ow}) values ranging from 2.13–4.29. Model performance was excellent, with a root mean squared error of 0.28 log units. This model has the potential to help identify suitable habitats for restocking under eel management plans. - Highlights: • A PBTK model was developed for European eel (Anguilla anguilla). • Own experimental data and data from the literature were used for parameterization. • The predictive power of the model was excellent, with RMSE of 0.28 log units. • The developed model can be amended with sub-models for dietary and dermal exposure.

  14. Pop up satellite tags impair swimming performance and energetics of the European eel (Anguilla anguilla)

    DEFF Research Database (Denmark)

    Methling, Caroline; Tudorache, Christian; Skov, Peter Vilhelm

    2011-01-01

    Pop-up satellite archival tags (PSATs) have recently been applied in attempts to follow the oceanic spawning migration of the European eel. PSATs are quite large, and in all likelihood their hydraulic drag constitutes an additional cost during swimming, which remains to be quantified, as does the...... and efficiency all are significantly affected in migrating eels with external tags....

  15. Temperature induced variation in gene expression of thyroid hormone receptors and deiodinases of European eel (Anguilla anguilla) larvae

    DEFF Research Database (Denmark)

    Politis, Sebastian Nikitas; Servili, A.; Mazurais, D.

    2018-01-01

    ) with 2 isoforms each (thrαA, thrαB, thrβA, thrβB) and 3 subtypes of deiodinases (dio1, dio2, dio3). All thr genes identified showed high similarity to the closely related Japanese eel (Anguilla japonica). We found that all genes investigated in this study were affected by larval age (in real time...... and dios, and iii) studied how temperature affects the expression of those genes in artificially produced early life history stages of European eel (Anguilla anguilla), reared in different thermal regimes (16, 18, 20 and 22°C) from hatch until first-feeding. We identified 2 subtypes of thr (thrα and thrβ...... or at specific developmental stages), temperature, and/or their interaction. More specifically, the warmer the temperature the earlier the expression response of a specific target gene. In real time, the expression profiles appeared very similar and only shifted with temperature. In developmental time, gene...

  16. Modification of essential fatty acid composition in broodstock of cultured European eel Anguilla anguilla L

    DEFF Research Database (Denmark)

    Støttrup, Josianne; Jacobsen, Charlotte; Tomkiewicz, Jonna

    2013-01-01

    (EFA) resembling wild European eel were sampled after 0, 5, 10, 14 and 44 weeks of feeding to examine changes in fatty acid composition (FAC) in ovaries, visceral fat and muscle. The results showed a slow but steady incorporation of EFA. Lipids are incorporated in the oocytes early in oogenesis...

  17. Light impacts embryonic and early larval development of the European eel, Anguilla anguilla

    DEFF Research Database (Denmark)

    Politis, Sebastian Nikitas; Butts, Ian; Tomkiewicz, Jonna

    2014-01-01

    Little is known about the natural ecology of European eel during early life history. Weextend our understandings on the ecology of this species by studying howearly life stages perform under various light regimes.We assessed the effects of intensity, photoperiod (12:12 and 24:0 h light/dark) and ...

  18. Tolerance of acute hypercapnic acidosis by the European eel ( Anguilla anguilla)

    DEFF Research Database (Denmark)

    McKenzie, D J; Taylor, E W; Dalla Valle, A Z

    2002-01-01

    at PwCO(2)s of 60 mm Hg and 80 mm Hg indicated that a portion of O(2) uptake was due to cutaneous respiration. Thus, the European eel's exceptional tolerance of acute hypercapnia is probably a consequence of the tolerance of its heart to acidosis and hypoxia, and a contribution to O(2) uptake from...

  19. Pop up satellite tags impair swimming performance and energetics of the European eel (Anguilla anguilla)

    DEFF Research Database (Denmark)

    Methling, Caroline; Tudorache, Christian; Skov, Peter Vilhelm

    2011-01-01

    increased oxygen consumption (MO(2)) during swimming and elevated minimum cost of transport (COT(min)) by 26 Standard (SMR) and active metabolic rate (AMR) as well as metabolic scope remained unaffected, suggesting that the observed effects were caused by increased drag. Optimal swimming speed (U......Pop-up satellite archival tags (PSATs) have recently been applied in attempts to follow the oceanic spawning migration of the European eel. PSATs are quite large, and in all likelihood their hydraulic drag constitutes an additional cost during swimming, which remains to be quantified, as does...... and efficiency all are significantly affected in migrating eels with external tags....

  20. Cardio-respiratory Physiology of the European Eel (Agunilla anguilla) in Extreme Environments

    DEFF Research Database (Denmark)

    Methling, Caroline

    The main objective of this PhD thesis was to study the cardio-respiratory capabilities of the European eel (Anguilla anguilla) under extreme conditions. Three environmental conditions were studied i.e. temperature, dissolved oxygen and carbon dioxide, while a fourth condition was physiological......-course of contraction, and thus maximum attainable heart rate in vivo, greatly depended on ambient temperature. The relative ventricular mass was increased after long term acclimation to 0°C and 10°C compared to individuals acclimated to 20°C, indicative of a compensatory mechanism for the limitation in heart rate...... and thus ensure adequate cardiac performance when diving to cooler depths. Furthermore, the individual contribution of three different sarcolemmal Ca2+ channels (L-type, NCX and SOCE) to the generation of force also depended on ambient temperature. Elevations in CO2 partial pressure (hypercapnia...

  1. Accumulation of neurotoxic organochlorines and trace elements in brain of female European eel (Anguilla anguilla).

    Science.gov (United States)

    Bonnineau, C; Scaion, D; Lemaire, B; Belpaire, C; Thomé, J-P; Thonon, M; Leermaker, M; Gao, Y; Debier, C; Silvestre, F; Kestemont, P; Rees, J-F

    2016-07-01

    Xenobiotics such as organochlorine compounds (OCs) and metals have been suggested to play a significant role in the collapse of European eel stocks in the last decades. Several of these pollutants could affect functioning of the nervous system. Still, no information is so far available on levels of potentially neurotoxic pollutants in eel brain. In present study, carried out on female eels caught in Belgian rivers and canals, we analyzed brain levels of potentially-neurotoxic trace elements (Ag, Al, As, Cd, Co, Cr, Cu, Fe, Hg, MeHg, Mn, Ni, Pb, Sn, Sb, Zn) and OCs (Polychlorinated biphenyls, PCBs; Hexachlorocyclohexanes, HCHs; Dichlorodiphenyltrichloroethane and its metabolites, DDTs). Data were compared to levels in liver and muscle tissues. Eel brain contained very high amounts of OCs, superior to those found in the two other tissues. Interestingly, the relative abundance of PCB congeners markedly differed between tissues. In brain, a predominance of low chlorinated PCBs was noted, whereas highly chlorinated congeners prevailed in muscle and liver. HCHs were particularly abundant in brain, which contains the highest amounts of β-HCH and ϒ-HCH. p,p'-DDTs concentration was similar between brain and muscle (i.e., about twice that of liver). A higher proportion of p,p'-DDT was noticed in brain. Except for Cr and inorganic Hg, all potentially neurotoxic metals accumulated in brain to levels equal to or lower than hepatic levels. Altogether, results indicate that eel brain is an important target for organic and, to a lesser extent, for inorganic neurotoxic pollutants. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Pop up satellite tags impair swimming performance and energetics of the European eel (Anguilla anguilla.

    Directory of Open Access Journals (Sweden)

    Caroline Methling

    Full Text Available Pop-up satellite archival tags (PSATs have recently been applied in attempts to follow the oceanic spawning migration of the European eel. PSATs are quite large, and in all likelihood their hydraulic drag constitutes an additional cost during swimming, which remains to be quantified, as does the potential implication for successful migration. Silver eels (L(T = 598.6±29 mm SD, N = 9 were subjected to swimming trials in a Steffensen-type swim tunnel at increasing speeds of 0.3-0.9 body lengths s(-1, first without and subsequently with, a scaled down PSAT dummy attached. The tag significantly increased oxygen consumption (MO(2 during swimming and elevated minimum cost of transport (COT(min by 26%. Standard (SMR and active metabolic rate (AMR as well as metabolic scope remained unaffected, suggesting that the observed effects were caused by increased drag. Optimal swimming speed (U(opt was unchanged, whereas critical swimming speed (U(crit decreased significantly. Swimming with a PSAT altered swimming kinematics as verified by significant changes to tail beat frequency (f, body wave speed (v and Strouhal number (St. The results demonstrate that energy expenditure, swimming performance and efficiency all are significantly affected in migrating eels with external tags.

  3. Pop up satellite tags impair swimming performance and energetics of the European eel (Anguilla anguilla).

    Science.gov (United States)

    Methling, Caroline; Tudorache, Christian; Skov, Peter V; Steffensen, John F

    2011-01-01

    Pop-up satellite archival tags (PSATs) have recently been applied in attempts to follow the oceanic spawning migration of the European eel. PSATs are quite large, and in all likelihood their hydraulic drag constitutes an additional cost during swimming, which remains to be quantified, as does the potential implication for successful migration. Silver eels (L(T) = 598.6±29 mm SD, N = 9) were subjected to swimming trials in a Steffensen-type swim tunnel at increasing speeds of 0.3-0.9 body lengths s(-1), first without and subsequently with, a scaled down PSAT dummy attached. The tag significantly increased oxygen consumption (MO(2)) during swimming and elevated minimum cost of transport (COT(min)) by 26%. Standard (SMR) and active metabolic rate (AMR) as well as metabolic scope remained unaffected, suggesting that the observed effects were caused by increased drag. Optimal swimming speed (U(opt)) was unchanged, whereas critical swimming speed (U(crit)) decreased significantly. Swimming with a PSAT altered swimming kinematics as verified by significant changes to tail beat frequency (f), body wave speed (v) and Strouhal number (St). The results demonstrate that energy expenditure, swimming performance and efficiency all are significantly affected in migrating eels with external tags.

  4. Hypercapnia adversely affects postprandial metabolism in the European eel (Anguilla anguilla)

    DEFF Research Database (Denmark)

    Methling, C.; Pedersen, Per Bovbjerg; Steffensen, John Fleng

    2013-01-01

    significantly increased the duration of the SDA response by 22% and 29%, respectively.Hypercapnia had no effect on standard metabolic rate,while constant or oscillating hypercapnia significantly lowered the maximum metabolic rate compared to controls, causing a significant reduction of the aerobic scope during...... ammonia excretion were observed at high pCO2 or low Ph/normocapnia. The results demonstrate that despite an exceptional tolerance towards elevated pCO2 and acidosis, postprandial metabolic processes of the European eel are adversely affected by hypercapnia and low pH...

  5. Musculoskeletal anatomy and feeding performance of pre-feeding engyodontic larvae of the European eel (Anguilla anguilla)

    Science.gov (United States)

    Bouilliart, Mathias; Tomkiewicz, Jonna; Lauesen, Peter; De Kegel, Barbara; Adriaens, Dominique

    2015-01-01

    Being part of the elopomorph group of fishes, Anguillidae species show a leptocephalus larval stage. However, due to largely unknown spawning locations and habitats of their earliest life stages, as well as their transparency, these Anguilla larvae are rarely encountered in nature. Therefore, information regarding the early life history of these larvae, including their exogenous feeding strategy and feeding performance, is rather scarce. To better understand the structural basis and functional performance of larval feeding in captivity, the functional morphology of the cranial musculoskeletal system in pre- and first-feeding engyodontic leptocephali of the European eel (Anguilla anguilla) was studied. A 3D reconstruction of the feeding apparatus (head of the leptocephali < 1 mm) was used to visualize and describe the musculoskeletal changes throughout these stages. To analyze the ontogenetic changes in the functionality of the feeding apparatus towards the active feeding phase, 3D data of joints, levers and muscles derived from the reconstructions were used to estimate bite and joint reaction forces (JRFs). Observing a maximum estimated bite force of about 65 μN (and corresponding JRFs of 260 μN), it can be hypothesized that leptocephalus larvae are functionally constrained to feed only on soft food particles. Additionally, potential prey items are size delimited, based on the theoretically estimated average gape of these larvae of about 100 μm. This hypothesis appears to be in line with recent observations of a diet consisting of small and/or gelatinous prey items (Hydrozoa, Thaliacea, Ctenophora, Polycystenia) found in the guts of euryodontic leptocephalus larvae. PMID:26278932

  6. Cardio-respiratory Physiology of the European Eel (Agunilla anguilla) in Extreme Environments

    DEFF Research Database (Denmark)

    Methling, Caroline

    The main objective of this PhD thesis was to study the cardio-respiratory capabilities of the European eel (Anguilla anguilla) under extreme conditions. Three environmental conditions were studied i.e. temperature, dissolved oxygen and carbon dioxide, while a fourth condition was physiological...... in attempts to follow the oceanic spawning migration of A. anguilla. Due to the size of these tags, it is likely that their hydraulic drag constitutes an additional cost during swimming, which may have implications for successful migration. In Paper IV, migration stage eels were subjected to swimming trials...... at increasing speeds of 0.3 - 0.9 body lengths s-1, first without and subsequently with, a scaled down PSAT dummy attached, while rates of oxygen consumption (MO2) were measured. The tag increased MO2 during swimming and elevated the minimum cost of transport (COTmin) by 26%. Standard (SMR) and active metabolic...

  7. Migratory life history of European eel Anguilla anguilla from freshwater regions of the River Asi, southern Turkey and their high otolith Sr:Ca ratios.

    Science.gov (United States)

    Lin, Y-J; Yalçin-Özdilek, S; Iizuka, Y; Gümüş, A; Tzeng, W-N

    2011-03-01

    Otolith Sr:Ca ratios from 32 of 34 European eel Anguilla anguilla collected from three freshwater sites in the River Asi, southern Turkey, indicated that they were resident in fresh water without apparent exposure to salt water since the elver stage. The Sr:Ca ratio criterion indicative of residence in fresh water was more than twice that of values from other European countries. Otolith Sr:Ca ratios of A. anguilla from fresh waters can vary among regions, possibly reflecting regional-specific water chemistry. Hence, the use of Sr:Ca ratios determined in one region to interpret results from a different region might lead to misclassification of migratory life-history types. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

  8. Fast muscle function in the European eel (Anguilla anguilla, L.) : during aquatic and terrestrial locomotion

    NARCIS (Netherlands)

    Ellerby, D.J.; Spierts, I.L.Y.; Altringham, J.D.

    2001-01-01

    Eels are capable of locomotion both in water and on land using undulations of the body axis. Axial undulations are powered by the lateral musculature. Differences in kinematics and the underlying patterns of fast muscle activation are apparent between locomotion in these two environments. The change

  9. Some Growth Parameters on European Eel (Anguilla anguilla L., 1758 Fed with Different Feeds.

    Directory of Open Access Journals (Sweden)

    Tülay Altun

    2015-12-01

    Full Text Available Farklı yemlerle beslenen avrupa yılanbalığı (Anguilla anguilla L.’nda bazı büyüme parametreleri. Bu çalışmanın amacı, balıkhane artıkları (BA, tavuk kesimhanesinin bazı artıkları (TA, kuru karma alabalık yemi (YY, balıkhane artıkları ile kuru karma alabalık yemi karışımı (BA+YY ve tavuk kesimhanesinin bazı artıkları ile kuru karma alabalık yemi karışımının (TA+YY Avrupa yılanbalığının bazı büyüme parametreleri üzerine etkisinin belirlenmesidir. Başlangıç ortalama ağırlığı 99,07±2,96g olan yılanbalıkları 80 günlük deneme süresi sonunda en iyi TA+YY yemi ile büyüme kaydetmiştir (128,56±1,75g. Bu grubun spesifik büyüme oranı % 0,33±0,02, yem değerlendirme oranı ise 8,82±0,29 olarak bulunmuştur. Bu grubu TA, BA+YY, YY, BA grupları izlemiştir. Canlı ağırlık ortalamaları gruplar arasında istatistiki olarak farklılık göstermiştir. BA grubunun sonuç ağırlık ortalaması taze balık eti verilen yılanbalıkları için bildirilen değerler arasındadır. Gruplarda görülen ölüm oranları %7,40±4,90 ile %16,66±3,21 arasında değişim göstermiştir

  10. Subcellular partitioning of non-essential trace metals (Ag, As, Cd, Ni, Pb, and Tl) in livers of American (Anguilla rostrata) and European (Anguilla anguilla) yellow eels

    Energy Technology Data Exchange (ETDEWEB)

    Rosabal, Maikel [Institut national de la recherche scientifique, Centre Eau Terre et Environnement (INRS–ETE), 490 de la Couronne, Québec (Québec) G1K 9A9 (Canada); Pierron, Fabien [Université de Bordeaux, UMR EPOC CNRS 5805, F-33400 Talence (France); CNRS, EPOC, UMR 5805, F-33400 Talence (France); Couture, Patrice [Institut national de la recherche scientifique, Centre Eau Terre et Environnement (INRS–ETE), 490 de la Couronne, Québec (Québec) G1K 9A9 (Canada); Baudrimont, Magalie [Université de Bordeaux, UMR EPOC CNRS 5805, F-33400 Talence (France); CNRS, EPOC, UMR 5805, F-33400 Talence (France); Hare, Landis [Institut national de la recherche scientifique, Centre Eau Terre et Environnement (INRS–ETE), 490 de la Couronne, Québec (Québec) G1K 9A9 (Canada); Campbell, Peter G.C., E-mail: peter.campbell@ete.inrs.ca [Institut national de la recherche scientifique, Centre Eau Terre et Environnement (INRS–ETE), 490 de la Couronne, Québec (Québec) G1K 9A9 (Canada)

    2015-03-15

    Highlights: • Handling of hepatic metals consistently involved cytosolic, thermostable ligands. • Granule-like fractions are also involved in the detoxification of Ni, Pb, and Tl. • Despite these sequestration mechanisms, metal detoxification is incomplete. • Along the metal gradient, concentrations increase in metal-sensitive fractions. • This increase could represent a toxicological risk for the yellow eels. - Abstract: We determined the intracellular compartmentalization of the trace metals Ag, As, Cd, Ni, Pb, and Tl in the livers of yellow eels collected from the Saint Lawrence River system in Canada (Anguilla rostrata) and in the area of the Gironde estuary in France (Anguilla anguilla). Differential centrifugation, NaOH digestion and thermal shock were used to separate eel livers into putative “sensitive” fractions (heat-denatured proteins, mitochondria and microsomes + lysosomes) and detoxified metal fractions (heat-stable peptides/proteins and granules). The cytosolic heat-stable fraction (HSP) was consistently involved in the detoxification of all trace metals. In addition, granule-like structures played a complementary role in the detoxification of Ni, Pb, and Tl in both eel species. However, these detoxification mechanisms were not completely effective because increasing trace metal concentrations in whole livers were accompanied by significant increases in the concentrations of most trace metals in “sensitive” subcellular fractions, that is, mitochondria, heat-denatured cytosolic proteins and microsomes + lysosomes. Among these “sensitive” fractions, mitochondria were the major binding sites for As, Cd, Pb, and Tl. This accumulation of non-essential metals in “sensitive” fractions likely represents a health risk for eels inhabiting the Saint Lawrence and Gironde environments.

  11. Strategy of recreational anglers and estimated eel (Anguilla anguilla catches in a large European catchment basin, the Loire (France

    Directory of Open Access Journals (Sweden)

    Baisez A.

    2009-04-01

    Full Text Available The European Council Regulation (18 September 2007 for the recovery of eel stocks required European states to report on eel stocks and anthropic mortalities. The data sources for France reveal gaps in our knowledge about angling in the public domain, and catches from privately-owned rivers. We tested a simple method, using a survey, for estimating the strategy employed and the catches landed by the 350 000 anglers fishing in the Loire catchment area. The first findings show that the answers of the fishermen varied between 1 and 2% in the departments with the most eels, and between 0.1 and 0.2% in the departments located further upstream. The interest in eel fishing, the average weight of the eels caught by the fishermen, and the total catch all decreased from downstream to upstream. Finally, we estimated the annual average weight of eel caught by anglers, which ranged from 0.8 to 5.3 kg per year depending on the department and the local interest in eel fishing. This preliminary study shows that it is possible to estimate the different fishing strategies used and the quantities caught by means of a survey.

  12. The effect of foraging and ontogeny on the prevalence and intensity of the invasive parasite Anguillicola crassus in the European eel Anguilla anguilla.

    Science.gov (United States)

    Barry, J; Newton, M; Dodd, J A; Evans, D; Newton, J; Adams, C E

    2017-09-01

    Infection patterns of the invasive Anguillicola crassus nematode were investigated in a population of the European eel Anguilla anguilla where parasite invasion is very recent, Loch Lomond, Scotland. Intensity levels of the parasite were associated with differences in fish ontogeny and trophic ecology. Although eels foraged on both fish and invertebrates, individuals which were smaller and fed on invertebrates (>70% contribution to diet) were found to contain a greater number of swim bladder parasites compared to larger eel with a predominance of fish (>60% contribution) in their diet. Within affected fish, a significant negative relationship was found between fish length and parasite intensity, with smaller individuals having higher parasite intensity than larger individuals. This study indicates that food intake and infection risk are linked in this recently infected host-parasite system. From a management perspective increasing our understanding of how infection intensity and repeated exposure is linked to resource use in an ecosystem is important for the future management of this endangered species in Europe. © 2017 The Authors. Journal of Fish Diseases Published by John Wiley & Sons Ltd.

  13. Temporal repeatability of metabolic rate and the effect of organ mass and enzyme activity on metabolism in European eel (Anguilla anguilla).

    Science.gov (United States)

    Boldsen, Martin Maagaard; Norin, Tommy; Malte, Hans

    2013-05-01

    Intraspecific variation in metabolic rate of fish can be pronounced and have been linked to various fitness-related behavioural and physiological traits, but the underlying causes for this variation have received far less attention than the consequences of it. In the present study we investigated whether European eels (Anguilla anguilla) displayed temporal repeatability of body-mass-corrected (residual) metabolic rate over a two-month period and if variations in organ mass and enzyme activity between individual fish could be the cause for the observed variation in metabolic rate. Both standard metabolic rate (SMR; Pearson's r=0.743) and routine metabolic rate (RMR; r=0.496) were repeatable over the two-month period. Repeatability of RMR is an interesting finding as it indicates that the level of spontaneous activity in respirometer-confined fish is not random. Cumulative organ mass (liver, heart, spleen and intestine; mean 1.6% total body mass) was found to explain 38% of the variation in SMR (r=0.613) with the liver (one of the metabolically most active organs) being the driver for the correlation between organ mass and metabolic rate. No relationships were found for either liver citrate synthase or cytochrome oxidase activity and metabolic rate in the European eels. Reasons for, and contributions to, the observed variation in metabolic rate are discussed. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Influence of temperature regime on endocrine parameters and vitellogenesis during experimental maturation of European eel (Anguilla anguilla) females

    NARCIS (Netherlands)

    Perez, L.; Penaranda, D.S.; Dufour, S.; Baloche, S.; Palstra, A.P.; Thillart, G.E.E.J.M.; Asturiano, J.F.

    2011-01-01

    We examined the effect of temperature in European silver eels during their maturation induced by injections of carp pituitary extract on endocrine parameters: pituitary fshß and lhß expression, plasma 17ß-estradiol (E2) and vitellogenin, estrogen receptor 1 (esr1), and vitellogenin 2 (vtg2)

  15. Gastrointestinal and metabolic effects of feeding schedule on voluntary feed intake and growth of European eel, Anguilla anguilla

    NARCIS (Netherlands)

    Heinsbroek, L.T.N.; Goedegebuur, B.J.; Bloemhof, G.; Flach, R.B.; Jong, de G.D.C.

    2008-01-01

    Gastrointestinal and metabolic influences on short- and medium-term control of voluntary feed intake of European eel were investigated for groups of fish fed at different feeding schedules: 1 meal 2 days(-1), 1 meal day(-1), 2 meals day(-1) and continuous feeding for 12 h and 24 h daily. For fish

  16. Influence of β-glucan Leiber(®)Beta-S on selected innate immunity parameters of European eel (Anguilla anguilla) in an intensive farming system.

    Science.gov (United States)

    Siwicki, Andrzej K; Schulz, Patrycja; Robak, Stanisław; Kazuń, Krzysztof; Kazuń, Barbara; Głąbski, Edward; Szczucińska, Ewa

    2015-01-01

    Nutritional support plays an important role in promoting high cellular and humoral innate immunity activity and in preventing outbreaks of disease. The effects of β-glucan Leiber(®)Beta-S dietary supplementation on selected nonspecific immune parameters in juvenile European eel (Anguilla anguilla) in an intensive culture system were studied. The fish were fed commercial pellets containing either 0 (control group) or 200 mg Leiber(®)Beta-S kg-1 of feed (glucan-fed group). After four and eight weeks of feeding, the levels of the following immunological parameters were measured: phagocyte respiratory burst activity, phagocyte potential killing activity, lymphocyte proliferation stimulated by concanavaline A or lipopolysaccharide, serum lysozyme activity, and total immunoglobulin (Ig) serum levels. After four and eight weeks of feeding 200 mg Leiber(®)Beta-S kg feed-1 the levels of all immune parameters were statistically significantly higher (p < 0.05) in the glucan-treated group than in the control group. After eight weeks of feeding the fish 200 mg Leiber(®)Beta-S kg feed-1 and after an additional eight weeks in ponds, the levels of all immune parameters, excluding lymphocyte proliferation stimulated by concanavaline A, were statistically significantly higher (p < 0.05) in the glucan-fed group than in the control group. These data suggest that feeding juvenile eel Leiber(®)Beta-S for four and eight weeks might improve innate immunity.

  17. Interactive effects of dietary composition and hormonal treatment on reproductive development of cultured female European eel, Anguilla anguilla

    DEFF Research Database (Denmark)

    da Silva, Filipa; Støttrup, Josianne Gatt; Kjørsvik, Elin

    2016-01-01

    weight (BW) and ii) a variable hormone dosage that increased from 12.5mg SPE/kg initial BW to 25mg SPE/kg initial BW. Results showed a significant interaction between diets and hormonal treatments on gonadosomatic index (GSI), indicating that the effect of broodstock diets on ovarian development depends......) in the plasma did not differ between diets and hormonal treatments, but was significantly correlated with ovarian developmental stage. In conclusion, increasing dietary levels of n-3 PUFAs seemed to promote oocyte growth, leading to a more rapid progression of ovarian development in European eel subjected...

  18. Swimming physiology of European silver eels (Anguilla anguilla L.): energetic costs and effects on sexual maturation and reproduction

    Science.gov (United States)

    van den Thillart, Guido E. E. J. M.

    2010-01-01

    The European eel migrates 5,000–6,000 km to the Sargasso Sea to reproduce. Because they venture into the ocean in a pre-pubertal state and reproduce after swimming for months, a strong interaction between swimming and sexual maturation is expected. Many swimming trials have been performed in 22 swim tunnels to elucidate their performance and the impact on maturation. European eels are able to swim long distances at a cost of 10–12 mg fat/km which is 4–6 times more efficient than salmonids. The total energy costs of reproduction correspond to 67% of the fat stores. During long distance swimming, the body composition stays the same showing that energy consumption calculations cannot be based on fat alone but need to be compensated for protein oxidation. The optimal swimming speed is 0.61–0.67 m s−1, which is ~60% higher than the generally assumed cruise speed of 0.4 m s−1 and implies that female eels may reach the Sargasso Sea within 3.5 months instead of the assumed 6 months. Swimming trials showed lipid deposition and oocyte growth, which are the first steps of sexual maturation. To investigate effects of oceanic migration on maturation, we simulated group-wise migration in a large swim-gutter with seawater. These trials showed suppressed gonadotropin expression and vitellogenesis in females, while in contrast continued sexual maturation was observed in silver males. The induction of lipid deposition in the oocytes and the inhibition of vitellogenesis by swimming in females suggest a natural sequence of events quite different from artificial maturation protocols. PMID:20390348

  19. Proteomic responses of peripheral blood mononuclear cells in the European eel (Anguilla anguilla) after perfluorooctane sulfonate exposure

    Energy Technology Data Exchange (ETDEWEB)

    Roland, Kathleen, E-mail: kathleen.roland@fundp.ac.be [Research Unit in Environmental and Evolutionary Biology (URBE), Narilis (Namur Research Institute for Lifesciences), University of Namur - FUNDP, Rue de Bruxelles 61, B-5000, Namur (Belgium); Kestemont, Patrick; Hénuset, Laurence; Pierrard, Marie-Aline [Research Unit in Environmental and Evolutionary Biology (URBE), Narilis (Namur Research Institute for Lifesciences), University of Namur - FUNDP, Rue de Bruxelles 61, B-5000, Namur (Belgium); Raes, Martine; Dieu, Marc [Research Unit in Cellular Biology (URBC) Narilis (Namur Research Institute for Lifesciences), University of Namur - FUNDP, Rue de Bruxelles 61, B-5000, Namur (Belgium); Silvestre, Frédéric [Research Unit in Environmental and Evolutionary Biology (URBE), Narilis (Namur Research Institute for Lifesciences), University of Namur - FUNDP, Rue de Bruxelles 61, B-5000, Namur (Belgium)

    2013-03-15

    Highlights: ► We have evaluating the toxicity of eel peripheral blood mononuclear cells exposed during 48 h to 10 μg and 1 mg perfluoroctane sulfonate/L. ► After in vitro contaminations, the post-nuclear fraction was isolated and a proteomic analysis using 2D-DIGE was performed. ► 48 different proteins were identified and classified into main functional classes which provide clues on the cellular pathways mainly affected by PFOS. -- Abstract: Since the 1980s, the stocks of European eel have been declining in most of their geographical distribution area. Many factors can be attributed to this decline such as pollution by xenobiotics like perfluorooctane sulfonate (PFOS). This study aimed at evaluating the in vitro toxicity of eel peripheral blood mononuclear cells (PBMC) exposed to PFOS. Exposure time and two concentrations were chosen to avoid cell mortality (48 h exposure at 10 μg PFOS/L and 1 mg PFOS/L). After in vitro contaminations, the post-nuclear fraction was isolated and a proteomic analysis using 2D-DIGE was performed to compare PBMC from the control group with cells exposed to the pollutant. On the 158 spots that were significantly affected by PFOS exposure, a total of 48 different proteins were identified using nano-LCESI-MS/MS and the Peptide and Protein Prophet of Scaffold software. These proteins can be categorized into diverse functional classes, related to cytoskeleton, protein folding, cell signaling, proteolytic pathway and carbohydrate and energy metabolism, which provide clues on the cellular pathways mainly affected by PFOS. Some of the identified proteins are rarely found in other ecotoxicological proteomic studies and could constitute potential biomarkers of exposure to PFOS in fish.

  20. Musculoskeletal anatomy and feeding performance of pre-feeding engyodontic larvae of the European eel (Anguilla anguilla)

    DEFF Research Database (Denmark)

    Bouilliart, M.; Tomkiewicz, Jonna; Lauesen, P.

    2015-01-01

    Being part of the elopomorph group of fishes, Anguillidae species show a leptocephalus larval stage. However, due to largely unknown spawning locations and habitats of their earliest life stages, as well as their transparency, these Anguilla larvae are rarely encountered in nature. Therefore, inf...

  1. European eel (Anguilla anguilla) genotoxic and pro-oxidant responses following short-term exposure to Roundup--a glyphosate-based herbicide.

    Science.gov (United States)

    Guilherme, S; Gaivão, I; Santos, M A; Pacheco, M

    2010-09-01

    The glyphosate-based herbicide, Roundup, is among the most used pesticides worldwide. Due to its extensive use, it has been widely detected in aquatic ecosystems representing a potential threat to non-target organisms, including fish. Despite the negative impact of this commercial formulation in fish, as described in literature, the scarcity of studies assessing its genotoxicity and underlying mechanisms is evident. Therefore, as a novel approach, this study evaluated the genotoxic potential of Roundup to blood cells of the European eel (Anguilla anguilla) following short-term (1 and 3 days) exposure to environmentally realistic concentrations (58 and 116 microg/l), addressing also the possible association with oxidative stress. Thus, comet and erythrocytic nuclear abnormalities (ENAs) assays were adopted, as genotoxic end points, reflecting different types of genetic damage. The pro-oxidant state was assessed through enzymatic (catalase, glutathione-S-transferase, glutathione peroxidase and glutathione reductase) and non-enzymatic (total glutathione content) antioxidants, as well as by lipid peroxidation (LPO) measurements. The Roundup potential to induce DNA strand breaks for both concentrations was demonstrated by the comet assay. The induction of chromosome breakage and/or segregational abnormalities was also demonstrated through the ENA assay, though only after 3-day exposure to both tested concentrations. In addition, the two genotoxic indicators were positively correlated. Antioxidant defences were unresponsive to Roundup. LPO levels increased only for the high concentration after the first day of exposure, indicating that oxidative stress caused by this agrochemical in blood was not severe. Overall results suggested that both DNA damaging effects induced by Roundup are not directly related with an increased pro-oxidant state. Moreover, it was demonstrated that environmentally relevant concentrations of Roundup can pose a health risk for fish populations.

  2. Full genome sequence of a novel circo-like virus detected in an adult European eel Anguilla anguilla showing signs of cauliflower disease.

    Science.gov (United States)

    Doszpoly, Andor; Tarján, Zoltán L; Glávits, Róbert; Müller, Tamás; Benkő, Mária

    2014-05-13

    An adult European eel Anguilla anguilla, showing typical signs of the so-called cauliflower disease, was subjected to pathological and molecular virological examinations. Samples taken from internal organs and the polypoid proliferative tissue from the mouth were examined by PCR for the detection of several viruses. Positive results were obtained with a nested PCR targeting the rep gene of circoviruses. Analysis of the partial rep sequence indicated the presence of a putative novel circovirus, but attempts to isolate it remained unsuccessful. The missing part of the genome was acquired by an inverse nested PCR with 2 specific primer pairs, designed from the newly determined rep sequence, followed by genome walking. The circular full genome was found to consist of 1378 nt (GenBank accession no. KC469701). Two oppositely oriented open reading frames (ORFs) were present, of which one was unambiguously identified as a circoviral rep gene. However, the predicted product of the other ORF, though it is a clear positional counterpart of the cap genes, showed no obvious homology to any known circoviral capsid proteins. A stem-loop-like element in the intergenic region between the 5' ends of the ORFs was also found. Phylogenetic calculations indicated that the novel virus belongs to the genus Circovirus in the family Circoviridae. The relative amount of the viral DNA in the organ samples was estimated by quantitative real-time PCR. The results suggested that the examined fish was caught in an active viremic state, although the role of this circovirus in the etiology of the cauliflower diseases could not be ascertained.

  3. Speciation and demographic history of Atlantic eels (Anguilla anguilla and A. rostrata) revealed by mitogenome sequencing

    DEFF Research Database (Denmark)

    Jacobsen, M.W.; Pujolar, J.M.; Gilbert, M.T.P.

    2014-01-01

    /North African and North American coasts, respectively. We analyzed 104 mitogenomes from the two species along with mitogenomes of other Anguilla and outgroup species. We estimated divergence time between the two species to identify major events involved in speciation. We also considered two previously stated......, coinciding with the closure of the Panama Gateway that led to reinforcement of the Gulf Stream. This could have advected larvae towards European/North African coasts, in which case American eel would be expected to be the ancestral species. This scenario could, however, not be unequivocally confirmed......Processes leading to speciation in oceanic environments without obvious physical barriers remain poorly known. European and American eel (Anguilla anguilla and A. rostrata) spawn in partial sympatry in the Sargasso Sea. Larvae are advected by the Gulf Stream and other currents towards the European...

  4. Gill lipid metabolism and unidirectional Na+ flux in the European eel (Anguilla anguilla) after transfer to dilute media

    DEFF Research Database (Denmark)

    Hansen, H.J.M.; Grosell, M.; Rosenkilde, P.

    1999-01-01

    The present study investigated the mechanism involved when fish tighten their gill membrane after transfer to dilute media. Ten individually assayed eels adapted to fresh water (EW) and labelled with radioactive Na-22 in the plasma showed mean exchange rates in equilibrium with ambient radioactive......% of the total C-14-activity incorporated into gill lipids as (C-14) wax alcohols (WA; octadecanol and eicosanol). This percentage went up to 50% shortly after transfer to DW and came down again to about 20% after 2 weeks in DW. Single eels labelled with Na-22 in the plasma showed a statistically significant...... positive linear correlation of percentage (14C) wax alcohols with log [22Na efflux]. Based on the observed parallel between Naf flux and gill lipid metabolism, it is suggested that the eel reacts at first to a loss of Na+ by synthesizing wax alcohols that can tighten the gill membrane. (C) 1999 Elsevier...

  5. Seawater acclimation and inositol monophosphatase isoform expression in the European eel (Anguilla anguilla) and Nile tilapia (Orechromis niloticus).

    Science.gov (United States)

    Kalujnaia, Svetlana; Gellatly, Steven A; Hazon, Neil; Villasenor, Alfredo; Yancey, Paul H; Cramb, Gordon

    2013-08-15

    Inositol monophosphatase (IMPA) is responsible for the synthesis of inositol, a polyol that can function as an intracellular osmolyte helping re-establish cell volume when exposed to hypertonic environments. Some epithelial tissues in euryhaline teleosts such as the eel and tilapia encounter considerable hyperosmotic challenge when fish move from freshwater (FW) to seawater (SW) environments; however, the roles played by organic osmolytes, such as inositol, have yet to be determined. Syntenic analysis has indicated that, as a result of whole genome- and tandem-duplication events, up to six IMPA isoforms can exist within teleost genomes. Four isoforms are homologs of the mammalian IMPA1 gene, and two isoforms are homologs of the mammalian IMPA2 gene. Although the tissue-dependent isoform expression profiles of the teleost isoforms appear to be species-specific, it was primarily mRNA for the IMPA1.1 isoform that was upregulated in epithelial tissues after fish were transferred to SW (up to 16-fold in eel and 90-fold in tilapia). Although up-regulation of IMPA1.1 expression was evident in many tissues in the eel, more substantial increases in IMPA1.1 expression were found in tilapia tissues, where SW acclimation resulted in up to 2,000-fold increases in protein expression, 16-fold increases in enzyme activity and 15-fold increases in tissue inositol contents. Immunohistochemical studies indicated that the tissue and cellular distribution of IMPA1.1 protein differed slightly between eels and tilapia; however, in both species the basal epithelial cell layers within the skin and fin, and the branchial epithelium and interstitial cells within the kidney, exhibited high levels of IMPA1.1 protein expression.

  6. Influence of preexposure to sublethal levels of copper on Cu-64 uptake and distribution among tissues of the European eel ( Anguilla anguilla )

    DEFF Research Database (Denmark)

    Grosell, M.; Boetius, I.; Hansen, H.J.M.

    1996-01-01

    The effect of preexposure to copper was examined in European eels with respect to uptake and distribution of Cu-64 among tissues. Eels were exposed in freshwater to 8 and 64 mu g Cu . L(-1) for 0, 6 and 28 days before Cu-64 incubation. The accumulation of copper in gill, liver and muscle tissue w...

  7. Implications of facultative catadromy in Anguilla anguilla. Does individual migratory behaviour influence eel spawner quality?

    Science.gov (United States)

    Marohn, Lasse; Jakob, Eva; Hanel, Reinhold

    2013-03-01

    European eel (Anguilla anguilla) recruitment is declining dramatically since the 1980s. Causes for this decline are explained by a combination of environmental changes basically affecting oceanic larval stages and a variety of anthropogenic impacts during the continental phase. Today, evidence is growing that poor silver eel quality has a major impact on reproductive success, implying that habitat quality plays a key role in stock decline. Since eels are frequently moving through a variety of different habitats during their life cycle, a better understanding of the implications of individual diadromous behaviour and habitat choice on spawner quality are crucial for management considerations for a stock recovery. The present study tested whether individual migratory behaviour and habitat choice of European eels affect spawner quality. Therefore, the migratory behaviour of 287 European eels from marine, brackish and freshwater stations in the North Sea, the Baltic Sea and from Northern German inland waters was examined by otolith strontium/calcium analysis. All individuals were classified either as freshwater residents, coastal residents, downstream shifters, upstream shifters or interhabitat shifters. As indicators for eel quality, muscle fat content, infection with the introduced swimbladder nematode Anguillicoloides crassus and body length at onset of spawning migration were assessed. Results indicate that individuals that exclusively inhabited freshwaters had significantly lower muscle fat contents and were more seriously infected with A. crassus than eels that never entered freshwaters. Since high fat contents are considered as prerequisites for a successful transoceanic spawning migration and high A. crassus loads have a negative impact on condition, this study outlines the importance of brackish waters as eel habitats in temperate latitudes. Furthermore, it questions the net benefit of stocking programs for the European eel population, since they include the

  8. Spatial variations and temporal trends between 1994 and 2005 in polychlorinated biphenyls, organochlorine pesticides and heavy metals in European eel (Anguilla anguilla L.) in Flanders, Belgium

    Energy Technology Data Exchange (ETDEWEB)

    Maes, Joachim [Research Institute for Nature and Forest (INBO), Duboislaan 14, B-1560 Groenendaal-Hoeilaart (Belgium)], E-mail: joachim.maes@vito.be; Belpaire, Claude [Research Institute for Nature and Forest (INBO), Duboislaan 14, B-1560 Groenendaal-Hoeilaart (Belgium)], E-mail: claude.belpaire@inbo.be; Goemans, Geert [Research Institute for Nature and Forest (INBO), Duboislaan 14, B-1560 Groenendaal-Hoeilaart (Belgium)], E-mail: geert.goemans@inbo.be

    2008-05-15

    In Flanders, the northern region of Belgium, European yellow eel muscle tissue was used as an indicator of environmental and potential human dietary exposure by hazardous chemicals of surface waters and sediments. Between 1994 and 2005, over 2800 eel captured at 365 stations were analysed for PCBs, pesticides and heavy metals. Contamination of eel in Flanders fell within the range of reported concentrations in other watersheds of Western Europe. A spatial analysis of the data demonstrated that the variation in pollutant concentration tended towards higher values. This was especially evident for PCBs, lindane, endrin, dieldrin and DDE. The concentration of almost all banned substances decreased significantly during the study period. - Although tissue concentrations of PCBs, pesticides and heavy metals decreased over time, they remain sufficiently high for the consumption of wild captured eel to still be discouraged.

  9. Effect of the slaughter method on the quality of raw and smoked eels (Anguilla anguilla L.)

    NARCIS (Netherlands)

    Morzel, M.; Vis, van de J.W.

    2003-01-01

    Eels (Anguilla anguilla L.) were slaughtered using two procedures. The commercial method consisted of desliming the fish in dry salt followed by evisceration. The alternative method consisted of stunning and killing in water with a combination of electricity and oxygen removal. Eels slaughtered as

  10. Effects of feed composition on life history developments in feed intake, metabolism, growth and body composition of European eel, Anguilla anguilla

    NARCIS (Netherlands)

    Heinsbroek, L.T.N.; Hooff, P.L.A.; Swinkels, W.; Tanck, M.W.T.; Schrama, J.W.; Verreth, J.A.J.

    2007-01-01

    To examine the effect of feed composition on changes in feed intake and subsequent feed utilization with age, five populations of European eel, with an average initial body weight of 5 g each fed a different diet, were monitored for 302 d. The five feeds differed in their content of crude protein

  11. Proteomic responses of peripheral blood mononuclear cells in the European eel (Anguilla anguilla) after perfluorooctane sulfonate exposure

    OpenAIRE

    Roland, K.; Kestemont, P.; Henuset, L.; Pierrard, M.-A.; Raes, M.; Dieu, M.; Silvestre, F.

    2013-01-01

    Since the 1980s, the stocks of European eel have been declining in most of their geographical distribution area. Many factors can be attributed to this decline such as pollution by xenobiotics like perfluorooctane sulfonate (PFOS). This study aimed at evaluating the in vitro toxicity of eel peripheral blood mononuclear cells (PBMC) exposed to PFOS. Exposure time and two concentrations were chosen to avoid cell mortality (48 h exposure at 10 mu g PFOS/L and 1 mg PFOS/L). After in vitro contami...

  12. Diet-induced phenotypic plasticity in head morphology in European eel elvers (Anguilla anguilla: the effects of hard vs soft food

    Directory of Open Access Journals (Sweden)

    Jens De Meyer

    2015-10-01

    Full Text Available By bone remodeling and changing of muscle volume, fish can adapt to changes in mechanical loads they are confronted with, including dietary changes such as prey hardness. This capability of a genotype to develop different phenotypes in response to varying environment is known as phenotypic plasticity. Differences in prey type being consumed might trigger such a phenotypic plasticity in fish. In European eel, two morphotypes exist: broadheads and narrowheads. Studies based on gut content have shown that broadheads consume larger and harder prey, such as fish, whereas narrowheads feed on smaller prey, such as benthic invertebrates. These studies, however, are performed on yellow eels with a minimum length of 30 cm, and only provide indirect evidence that head shape is affected by diet differences. Here, we performed a feeding experiment on glass eels that just swam up the European rivers to start feeding. These glass eels were captured and separated in three groups: one group was given hard feed requiring biting, the second group got soft feed that could be sucked in and the final group, which acted as a control group, was given a mixture of both. We found that hard feeders developed a broader general head width and postorbital region than soft feeders. This region is associated with the location of the jaw muscles, indicating that hard feeders develop larger muscles to cope with the harder prey. Hard feeders, however, also grew more slowly than soft feeders, suggesting that net energy uptake of hard feeders was lower as prey handling required more energy and time. Specimens of the control group, finally, developed intermediate head widths, implying that they are not fully adapted to feed on either hard or soft prey. In conclusion, this study provides the first direct evidence that diet influences the head shape of European eel.

  13. Macroparasite communities in European eels, Anguilla anguilla, from French Mediterranean lagoons, with special reference to the invasive species Anguillicola crassus and Pseudodactylogyrus spp.

    Directory of Open Access Journals (Sweden)

    G. Fazio

    2008-01-01

    Full Text Available European eel parasites, in particular invasive species, are suspected to play a role in the decline in the populations of their host. The aims of this work were to describe the parasitic fauna of eels in French Mediterranean lagoons and to study the epidemiological trends of the invasive helminth species, the nematode Anguillicola crassus and the monogenean Pseudodactylogyrus spp., in regard to spatio-temporal dynamics, host biological characteristics and parasite community. A total of 418 eels was sampled in eight lagoons between March 2003 and June 2005. Our results revealed a total macroparasite richness of 23 species: 1 Monogenea, 13 Digenea, 2 Cestoda, 3 Nematoda, 2 Acantocephala and 2 Crustacea. We found no variation in A. crassus abundance in Salses-Leucate lagoon in the same month across years. However, the nematode abundance was higher in eels caught in summer than in those caught in winter. Pseudodactylogyrus sp. was not found in Salses-Leucate lagoon, except in July 2004. Comparisons between the lagoons on the same date showed that they could be separated into two groups for both species' abundance: Grau-du-Roi, Mauguio, Palavas and Vaccarès lagoons, where abundance was rather high, against Bages-Sigean, Pierre-Blanche, Salses-Leucate and Thau lagoons, where abundance was rather low or nil. We found significant negative relationships between A. crassus abundance and the length and age of eels. We also found a significant positive relationship between A. crassus and Pseudodactylogyrus sp. abundance. Finally, our results showed significant positive relationships between both A. crassus and Pseudodactylogyrus sp. abundance and the abundance of the digeneans Prosorhynchus aculeatus and Lecithochirium gravidum. We discuss the results in regard to the dynamics of invasions, the characteristics of the parasite life cycles and the ecology of eels.

  14. First artificial hybrid of the eel species Anguilla australis and Anguilla anguilla

    Directory of Open Access Journals (Sweden)

    Dirks Ron P

    2011-03-01

    Full Text Available Abstract Background Studies on artificial hybridization of different Anguilla species were conducted recently, i.e. female A. australis with male A. dieffenbachii, and female A. japonica with male A. anguilla. The existence of these artificial hybrids was however not demonstrated by independent genetic methods. Two species - A. anguilla and A. australis - that are phylogenetically close but have different sexual maturation times (12-25 weeks and 6-8 weeks, respectively, were expected to produce favourable hybrids for reproduction studies. Results A modification of the protocol for the reproduction of Anguilla japonica was used to produce eight-day Anguilla australis larvae, with a success rate of 71.4%. Thus ten out of 14 females produced eggs that could be fertilized, and three batches resulted in mass hatching. Hybrid larvae from female A. australis x male A. Anguilla survived for up to seven days post fertilization (dpf. The early development of the hybrid showed typical characteristics of A. anguilla tail pigmentation at 50 hours post fertilization (hpf, indicating expression of genes derived from the father. Conclusions In this paper we describe the first production of hybrid larvae from male A. anguilla and female A. australis and their survival for up to 7 dpf. A species-specific nucleotide difference in the 18 S rDNA gene confirmed that genes from both A. australis and A. anguilla were present in the hybrids. The developmental stages of the hybrid eel embryos and larvae are described using high resolution images. Video footage also indicated a heart beat in 5-dpf larva.

  15. Assessing pre- and post-zygotic barriers between North Atlantic eels (Anguilla anguilla and A. rostrata)

    DEFF Research Database (Denmark)

    Jacobsen, M. W.; Smedegaard, L.; Sørensen, Sune Riis

    2017-01-01

    Elucidating barriers to gene flow is important for understanding the dynamics of speciation. Here we investigate pre- and post-zygotic mechanisms acting between the two hybridizing species of Atlantic eels: Anguilla anguilla and A. rostrata. Temporally varying hybridization was examined by analyz...... in natural hybrids.Heredity advance online publication, 9 November 2016; doi:10.1038/hdy.2016.96....

  16. Element concentrations in the swimbladder parasite Anguillicola crassus (nematoda) and its host the European eel, Anguilla anguilla from Asi River (Hatay-Turkey).

    Science.gov (United States)

    Genc, Ercument; Sangun, M Kemal; Dural, Meltem; Can, M Fatih; Altunhan, Cem

    2008-06-01

    The European eel's swimbladder nematode, Anguillicola crassus, sampled from the Asi River (Orontes River) in Antakya (Hatay, Turkey) in May 2006 were analysed by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) for their some heavy metal (Cd, Cr, Cu, Fe, Hg, Mn, Pb and Zn) levels. The metal concentrations of the parasites were compared to different organs (swimbladder, liver, muscle and skin) of the fish hosts. The parasite contained statistically highly significantly amounts of Fe (P 0.05). Furthermore, no significant differences were detected in the heavy metal accumulations between the parasitized and un-parasitized fish tissues. The analysed metals (Cd, Cr, Cu, Fe, Mn, Pb and Zn) were found in fish muscle at mean concentrations under the permissible limits proposed by FAO.

  17. Myo-inositol phosphate synthase expression in the European eel (Anguilla anguilla) and Nile tilapia (Oreochromis niloticus): effect of seawater acclimation

    OpenAIRE

    Kalujnaia, Svetlana; Hazon, Neil; Cramb, Gordon

    2016-01-01

    The work was funded by a research grant awarded to GC and NH by the Natural Environment Research Council (NE/J010081/1). A single MIPS gene (Isyna1/Ino1) exists in eel and tilapia genomes with a single MIPS transcript identified in all eel tissues, although two MIPS spliced variants (termed MIPS(s) and MIPS(l)) are found in all tilapia tissues. The larger tilapia transcript (MIPS(l)) results from the inclusion of the 87-nucleotide intron between exons 5 and 6 in the genomic sequence. In mo...

  18. Slow muscle power output of yellow- and silver-phase European eels (Anguilla anguilla L.) : changes in muscle performance prior to migration

    NARCIS (Netherlands)

    Ellerby, D.J.; Spierts, I.L.Y.; Altringham, J.D.

    2001-01-01

    Eels swim in the anguilliform mode in which the majority of the body axis undulates to generate thrust. For this reason, muscle function has been hypothesised to be relatively uniform along the body axis relative to some other teleosts in which the caudal fin is the main site of thrust production.

  19. The Effect of Prolonged Fasting on Total Lipid Synthesis and Enzyme Activities in the Liver of the European Eel (Anguilla anguilla)

    DEFF Research Database (Denmark)

    Abraham, S. A.; Hansen, Heinz Johs. Max; Hansen, F.N.

    1984-01-01

    The extent of fatty acid synthesis from [1-14C]acetate in liver slices was reduced 6-fold when eels were fasted for 1-7 wk and 20-fold when fasted for 39 wk, thereafter hepatic lipogenesis seemed to remain constant for up to 95 wk of fasting. After a 1-3 wk fast some hepatic enzyme activities wer...

  20. Influence of Temperature, Environmental Salinity and Fasting on the Patterns of Fatty Acid Synthesized by Gills and Liver of the European Eel (Anguilla Anguilla)

    DEFF Research Database (Denmark)

    Hansen, Heinz Johs. Max; Abraham, S.

    1983-01-01

    A rise in temperature on the average from 8 to 28 degrees C resulted in an enhanced relative incorporation of 1-14Cacetate into saturated fatty acids in liver tissue. The same effect was seen in gill tissue, but only after incubation in vitro and when the precursor was injected into the eel. When 1...

  1. Myo-inositol phosphate synthase expression in the European eel (Anguilla anguilla) and Nile tilapia (Oreochromis niloticus): effect of seawater acclimation.

    Science.gov (United States)

    Kalujnaia, Svetlana; Hazon, Neil; Cramb, Gordon

    2016-08-01

    A single MIPS gene (Isyna1/Ino1) exists in eel and tilapia genomes with a single myo-d-inositol 3-phosphate synthase (MIPS) transcript identified in all eel tissues, although two MIPS spliced variants [termed MIPS(s) and MIPS(l)] are found in all tilapia tissues. The larger tilapia transcript [MIPS(l)] results from the inclusion of the 87-nucleotide intron between exons 5 and 6 in the genomic sequence. In most tilapia tissues, the MIPS(s) transcript exhibits much higher abundance (generally >10-fold) with the exception of white skeletal muscle and oocytes, in which the MIPS(l) transcript predominates. SW acclimation resulted in large (6- to 32-fold) increases in mRNA expression for both MIPS(s) and MIPS(l) in all tilapia tissues tested, whereas in the eel, changes in expression were limited to a more modest 2.5-fold increase and only in the kidney. Western blots identified a number of species- and tissue-specific immunoreactive MIPS proteins ranging from 40 to 67 kDa molecular weight. SW acclimation failed to affect the abundance of any immunoreactive protein in any tissue tested from the eel. However, a major 67-kDa immunoreactive protein (presumed to be MIPS) found in tilapia tissues exhibited 11- and 54-fold increases in expression in gill and fin samples from SW-acclimated fish. Immunohistochemical investigations revealed specific immunoreactivity in the gill, fin, skin, and intestine taken from only SW-acclimated tilapia. Immunofluorescence indicated that MIPS was expressed within gill chondrocytes and epithelial cells of the primary filaments, basal epithelial cell layers of the skin and fin, the cytosol of columnar intestinal epithelial and mucous cells, as well as unknown entero-endocrine-like cells. Copyright © 2016 the American Physiological Society.

  2. Behaviour and passage of European silver eels (Anguilla anguilla at a small hydropower plant during their downstream migration Comportement et passage de l’anguille argentée (Anguilla anguilla au niveau d’une petite centrale hydroélectrique lors de sa migration de dévalaison

    Directory of Open Access Journals (Sweden)

    De-Oliveira E.

    2010-09-01

    Full Text Available Between 2004 and 2007, 116 downstream migrant silver eels (Anguilla anguilla were monitored at a hydropower plant on the Gave de Pau river in South-West France using radio and PIT telemetry. The objectives of the study were: (i to determine the environmental conditions when eels arrived and passed the facility; (ii to determine the rate of eel escapement (passage other than via the turbines; (iii to describe the behaviour of eels faced with the intake structure and the permeability of the intake trashracks for the different sizes of eel; and (iv to determine whether surface bypasses originally designed for salmon could be effective for eels. Five types of behaviour of silver eels in the forebay and at the plant intakes were identified. The study showed the key factor influencing both eel behaviour and the route taken through the plant was variation in river discharge. Escapement rate was related to eel length and the spill flow to river flow ratio, which could be described by a logistic regression model. The surface bypasses originally designed for salmon were found to aid downstream eel migration significantly. At velocities < 0.40 m·s−1, no eels, even the largest, for which the racks are a physical barrier, were found impinged on the trashracks. De 2004 à 2007, une étude sur la migration de dévalaison de l’anguille argentée européenne (Anguilla anguilla a été menée sur la centrale hydroélectrique de Baigts sur le Gave de Pau dans le Sud-Ouest de la France. Cette étude, au cours de laquelle 116 individus ont été suivis par télémétrie PIT et radio, avait pour objectifs : (i de déterminer les conditions de milieu propices à l’arrivée sur site et au franchissement de l’aménagement; (ii de déterminer les taux d’échappement (passages par des voies autres que les turbines; (iii d’analyser le comportement des anguilles devant les ouvrages et la perméabilité des grilles de la prise d’eau en fonction de la taille

  3. Stage-specific distribution models can predict eel (Anguilla anguilla) occurrence during settlement in coastal lagoons

    Science.gov (United States)

    Leone, C.; Zucchetta, M.; Capoccioni, F.; Gravina, M. F.; Franzoi, P.; Ciccotti, E.

    2016-03-01

    Eel (Anguilla anguilla) is a catadromous fish species typical of Mediterranean coastal lagoons, that currently suffers from several anthropogenic and natural impacts. These are thought to be the cause of a stock-wide decline that this panmictic species is facing, in inland and coastal waters of Europe and North Africa. The decline affects both adult phases and recruitment, i.e. glass eel arrival to coastal waters and their ascent to inland waters. Quantitative features of eel recruitment reflect a transoceanic global scale, but also depend on local environmental conditions, the latter also affecting settlement dynamics in transitional waters. There is only little information on the dynamics of these two processes in coastal lagoons, notwithstanding the paramount importance of both in sustaining local stocks abundance and their demographic structure for this typical but also economically important inhabitant of Mediterranean lagoons, habitats that constitute an important share of the eel distribution area. The present study aims, therefore, to clarify space and time dynamics of local scale recruitment and of settlement in a coastal lagoon in the Mediterranean area, also by setting up a specific methodological approach. For this purpose, data from field surveys in combination with Species Distribution Models (SDMs) have been used in order to relate distribution of eel juvenile stages to the environmental conditions within the lagoon. Specifically, models were calibrated to quantify the relationship between presence of juvenile eel and the main environmental drivers, with the aim of identifying potential habitats for eel settlement within the lagoon. Results gained by modelling suggest certain spatial and temporal colonization patterns for the juvenile eel in the Fogliano lagoon, a typical Mediterranean coastal lake. The modelling approach has therefore proved to be a useful tool for predicting habitats for eel recruitment at the local scale and settlement, because

  4. Replicating phages in the epidermal mucosa of the eel (Anguilla anguilla

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    Miguel eCarda Diéguez

    2015-01-01

    Full Text Available In this work, we used the eel (Anguilla anguilla as an animal model to test the hypothesis of Barr et al. about the putative role of the epidermal mucosa as a phage enrichment layer. To this end, we analyzed the microbial content of the skin mucus of wild and farmed eels by using a metagenomic approach. We found a great abundance of replicating phages (concatemers in all the samples. They were assembled in four complete genomes of three Myovirus and one Podovirus. We also found evidences that ΦKZ and Podovirus phages could be part of the resident microbiota associated to the eel mucosal surface and persist on them over the time. Moreover, the viral abundance estimated by epiflorescent counts and by metagenomic recruitment from eel mucosa was higher than that of the surrounding water. Taken together, our results support the hypothesis that claims a possible role of phages in the animal mucus as agents controlling bacterial populations, including pathogenic species, providing a kind of innate immunity.

  5. Analyses of organochlorine pesticides residues in eels (Anguilla anguilla from Lake Garda using Gas chromatography coupled with Tandem Mass Spectrometry (GC-MS/MS.

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    Giuseppe Federico Labella

    2017-05-01

    Full Text Available Lake Garda is located in Insubria region, that is known for being the most populated and industrialized area of Italy (Camusso et al., 2001. Therefore, the Lake water, and also the fish species present, could be affected by environmental contamination.  European eel (Anguilla anguilla are considered as suitable matrix for biomonitoring environmental contaminants in European water (Belpaire et al., 2007, being widespread in many European waters and highly contaminated by lipophilic compounds, due to the high lipid content (up to 40% (Larsson et al., 1991. Moreover, eel is an edible species (its farming currently supplies approximately 45,000 tons/year (Nielsen et al., 2008, so it also represents a public health issue. Based on these considerations, the aim of this study was to evaluate the occurrence of fourteen organochlorine pesticides (OCs in forty-five eels (Anguilla anguilla from Lake Garda, using Accelerated Solvent Extraction (ASE procedure for the analytes extraction and Gas chromatography coupled with Tandem Mass Spectrometry (GC-MS/MS for the analysis of OCs. GC-MS/MS analysis was developed and validated according to the SANTE/11945/2015 guidelines.  Uncontaminated eel sample (previously checked for the presence of OCs and considered blank with a concentration of compounds < Limit of Detection were used for all procedure's optimization steps. For all the OCs analysed, satisfactory results were achieved. Regarding eel samples, several pesticides were detected, but DDTs (DDT and its metabolites were found with the highest prevalence (92 %. The concentration rage was from not detected (n.d. to 19000 ng g-1. Although DDTs levels in the environment are declining (Albaiges et al., 2011, they continue to bioaccumulate in tissues of human and animal and biomagnify in food chains.

  6. First artificial hybrid of the eel species Anguilla australis and Anguilla anguilla

    NARCIS (Netherlands)

    Burgerhout, E.; Brittijn, S.A.; Kurwie, T.; Decker, P.; Dirks, R.; Palstra, A.P.; Spaink, H.P.; Thillart, G.E.E.J.M.

    2011-01-01

    Background: Studies on artificial hybridization of different Anguilla species were conducted recently, i.e. female A. australis with male A. dieffenbachii, and female A. japonica with male A. anguilla. The existence of these artificial hybrids was however not demonstrated by independent genetic

  7. The giant mottled eel, Anguilla marmorata, uses blue-shifted rod photoreceptors during upstream migration.

    Science.gov (United States)

    Wang, Feng-Yu; Fu, Wen-Chun; Wang, I-Li; Yan, Hong Young; Wang, Tzi-Yuan

    2014-01-01

    Catadromous fishes migrate between ocean and freshwater during particular phases of their life cycle. The dramatic environmental changes shape their physiological features, e.g. visual sensitivity, olfactory ability, and salinity tolerance. Anguilla marmorata, a catadromous eel, migrates upstream on dark nights, following the lunar cycle. Such behavior may be correlated with ontogenetic changes in sensory systems. Therefore, this study was designed to identify changes in spectral sensitivity and opsin gene expression of A. marmorata during upstream migration. Microspectrophotometry analysis revealed that the tropical eel possesses a duplex retina with rod and cone photoreceptors. The λmax of rod cells are 493, 489, and 489 nm in glass, yellow, and wild eels, while those of cone cells are 508, and 517 nm in yellow, and wild eels, respectively. Unlike European and American eels, Asian eels exhibited a blue-shifted pattern of rod photoreceptors during upstream migration. Quantitative gene expression analyses of four cloned opsin genes (Rh1f, Rh1d, Rh2, and SWS2) revealed that Rh1f expression is dominant at all three stages, while Rh1d is expressed only in older yellow eel. Furthermore, sequence comparison and protein modeling studies implied that a blue shift in Rh1d opsin may be induced by two known (N83, S292) and four putative (S124, V189, V286, I290) tuning sites adjacent to the retinal binding sites. Finally, expression of blue-shifted Rh1d opsin resulted in a spectral shift in rod photoreceptors. Our observations indicate that the giant mottled eel is color-blind, and its blue-shifted scotopic vision may influence its upstream migration behavior and habitat choice.

  8. The giant mottled eel, Anguilla marmorata, uses blue-shifted rod photoreceptors during upstream migration.

    Directory of Open Access Journals (Sweden)

    Feng-Yu Wang

    Full Text Available Catadromous fishes migrate between ocean and freshwater during particular phases of their life cycle. The dramatic environmental changes shape their physiological features, e.g. visual sensitivity, olfactory ability, and salinity tolerance. Anguilla marmorata, a catadromous eel, migrates upstream on dark nights, following the lunar cycle. Such behavior may be correlated with ontogenetic changes in sensory systems. Therefore, this study was designed to identify changes in spectral sensitivity and opsin gene expression of A. marmorata during upstream migration. Microspectrophotometry analysis revealed that the tropical eel possesses a duplex retina with rod and cone photoreceptors. The λmax of rod cells are 493, 489, and 489 nm in glass, yellow, and wild eels, while those of cone cells are 508, and 517 nm in yellow, and wild eels, respectively. Unlike European and American eels, Asian eels exhibited a blue-shifted pattern of rod photoreceptors during upstream migration. Quantitative gene expression analyses of four cloned opsin genes (Rh1f, Rh1d, Rh2, and SWS2 revealed that Rh1f expression is dominant at all three stages, while Rh1d is expressed only in older yellow eel. Furthermore, sequence comparison and protein modeling studies implied that a blue shift in Rh1d opsin may be induced by two known (N83, S292 and four putative (S124, V189, V286, I290 tuning sites adjacent to the retinal binding sites. Finally, expression of blue-shifted Rh1d opsin resulted in a spectral shift in rod photoreceptors. Our observations indicate that the giant mottled eel is color-blind, and its blue-shifted scotopic vision may influence its upstream migration behavior and habitat choice.

  9. Magnetic compass orientation in the European eel.

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    Caroline M F Durif

    Full Text Available European eel migrate from freshwater or coastal habitats throughout Europe to their spawning grounds in the Sargasso Sea. However, their route (~ 6000 km and orientation mechanisms are unknown. Several attempts have been made to prove the existence of magnetoreception in Anguilla sp., but none of these studies have demonstrated magnetic compass orientation in earth-strength magnetic field intensities. We tested eels in four altered magnetic field conditions where magnetic North was set at geographic North, South, East, or West. Eels oriented in a manner that was related to the tank in which they were housed before the test. At lower temperature (under 12°C, their orientation relative to magnetic North corresponded to the direction of their displacement from the holding tank. At higher temperatures (12-17°C, eels showed bimodal orientation along an axis perpendicular to the axis of their displacement. These temperature-related shifts in orientation may be linked to the changes in behavior that occur between the warm season (during which eels are foraging and the colder fall and winter (during which eels undertake their migrations. These observations support the conclusion that 1. eels have a magnetic compass, and 2. they use this sense to orient in a direction that they have registered moments before they are displaced. The adaptive advantage of having a magnetic compass and learning the direction in which they have been displaced becomes clear when set in the context of the eel's seaward migration. For example, if their migration is halted or blocked, as it is the case when environmental conditions become unfavorable or when they encounter a barrier, eels would be able to resume their movements along their old bearing when conditions become favorable again or when they pass by the barrier.

  10. Microbial interference with hatch and survival of European eel larvae

    DEFF Research Database (Denmark)

    Sørensen, Sune Riis; Lauesen; Tomkiewicz, Jonna

    Recent research has significantly improved our knowledge and capabilities in the field of in vitro production of yolk sac larvae from European eel (Anguilla anguilla). Female broodstock European eels are matured by weekly administration of pituitary extract and male eels with hCG (human chorionic...... gonadotropin), which afford gametes for in vitro fertilization studies. The maturing process may lead to mass hatchings of up to ½ million larvae of which some survive the entire yolk sac phase. However, the rearing of larvae suffers from high larval mortalities, and water quality might be a crucial factor...... for larval survival in rearing systems. By applying antibiotic treatment as a research tool, it was possible to determine the extent of microbial interference in the production of high numbers of good quality larvae. By controlling microbiota during egg and larval incubation, the egg hatching success...

  11. Chromatographic and immunological evidence for mammalian GnRH and chicken GnRH II in eel (Anguilla anguilla) brain and pituitary.

    Science.gov (United States)

    King, J A; Dufour, S; Fontaine, Y A; Millar, R P

    1990-01-01

    Gonadotropin-releasing hormone (GnRH) peptides in the brain and pituitary of the European eel (Anguilla anguilla) were investigated by reverse phase high performance liquid chromatography (HPLC) and radioimmunoassay with region-specific antisera. Two GnRH molecular forms were demonstrated in brain and pituitary extracts. One form eluted in the same position as synthetic mammalian GnRH on HPLC and was recognized by antibodies directed against the NH2 and COOH termini of mammalian GnRH as well as by antibodies to the middle region. The second form eluted in the same position as synthetic chicken GnRH II and was recognized by specific antibodies to this molecule. Salmon GnRH and chicken GnRH I were not detected. The occurrence of mammalian GnRH in teleost fish suggests that this molecular form is more ancient than was previously suspected and arose earlier than in primitive tetrapods, or that it has arisen in the eel through random mutation of salmon GnRH. The lack of salmon GnRH in the eel brain indicates that this molecular form is not common to all teleost species. The finding in eel brain of chicken GnRH II, which has previously been described in species of Mammalia, Aves, Reptilia, Amphibia, Osteichthyes, and Chondrichthyes, supports our hypothesis that this widespread structural variant may represent an early evolved and conserved form of GnRH.

  12. Primitive duplicate Hox clusters in the European eel's genome.

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    Christiaan V Henkel

    Full Text Available The enigmatic life cycle and elongated body of the European eel (Anguilla anguilla L., 1758 have long motivated scientific enquiry. Recently, eel research has gained in urgency, as the population has dwindled to the point of critical endangerment. We have assembled a draft genome in order to facilitate advances in all provinces of eel biology. Here, we use the genome to investigate the eel's complement of the Hox developmental transcription factors. We show that unlike any other teleost fish, the eel retains fully populated, duplicate Hox clusters, which originated at the teleost-specific genome duplication. Using mRNA-sequencing and in situ hybridizations, we demonstrate that all copies are expressed in early embryos. Theories of vertebrate evolution predict that the retention of functional, duplicate Hox genes can give rise to additional developmental complexity, which is not immediately apparent in the adult. However, the key morphological innovation elsewhere in the eel's life history coincides with the evolutionary origin of its Hox repertoire.

  13. Donor life stage influences juvenile American eel Anguilla rostrata attraction to conspecific chemical cues

    Science.gov (United States)

    Galbraith, Heather S.; Blakeslee, Carrie J.; Schmucker, Andrew K.; Johnson, Nicholas; Hansen, Michael J.; Li, Weiming

    2017-01-01

    The present study investigated the potential role of conspecific chemical cues in inland juvenile American eel Anguilla rostrata migrations by assessing glass eel and 1 year old elver affinities to elver washings, and elver affinity to adult yellow eel washings. In two-choice maze assays, glass eels were attracted to elver washings, but elvers were neither attracted to nor repulsed by multiple concentrations of elver washings or to yellow eel washings. These results suggest that A. rostrata responses to chemical cues may be life-stage dependent and that glass eels moving inland may use the odour of the previous year class as information to guide migration. The role of chemical cues and olfaction in eel migrations warrants further investigation as a potential restoration tool.

  14. Using interview-based recall surveys to estimate cod Gadus morhua and eel Anguilla anguilla harvest in Danish recreational fishing

    DEFF Research Database (Denmark)

    Sparrevohn, Claus Reedtz; Storr-Paulsen, Marie

    2012-01-01

    Using interview-based recall surveys to estimate cod Gadus morhua and eel Anguilla anguilla harvest in Danish recreational fishing. – ICES Journal of Marine Science, 69: 323–330.Marine recreational fishing is a popular outdoor activity in Denmark, practised by both anglers and passive gear fishers...... with the mandatory Danish fishing licence. The second survey was designed to identify those who fish without a licence. It was estimated that 1231 t of cod were harvested in 2009, corresponding to 4.8% of the entire Danish cod yield (recreational harvest + commercial landings). Area differences were found, and...... to 19% of the entire Danish eel yield. The inclusion of the harvest taken by fishers without a valid licence was important and added almost 20% to the estimated harvest....

  15. Evaluation of three telemetry transmitter attachment methods for female silver-phase American eels ( Anguilla rostrata Lesueur)

    DEFF Research Database (Denmark)

    Cottrill, R.A.; Økland, F.; Aarestrup, Kim

    2006-01-01

    Declines in juvenile American eel (Anguilla rostrata Lesueur) abundance have led to concern about the impacts of anthropogenic structures on eel migration patterns. Telemetry provides an insightful tool for examining the movements of eels around these structures. Although there have been a number...

  16. Assessing patterns of hybridization between North Atlantic eels using diagnostic single-nucleotide polymorphisms

    DEFF Research Database (Denmark)

    Pujolar, José Martin; Jacobsen, M.W.; Als, Thomas Damm

    2014-01-01

    The two North Atlantic eel species, the European eel (Anguilla anguilla) and the American eel (Anguilla rostrata), spawn in partial sympatry in the Sargasso Sea, providing ample opportunity to interbreed. In this study, we used a RAD (Restriction site Associated DNA) sequencing approach to identi...

  17. Induction of biotransformation in the liver of Eel (Anguilla anguilla L. ) by sublethal exposure to dinitro-o-cresol: An ultrastructural and biochemical study

    Energy Technology Data Exchange (ETDEWEB)

    Braunbeck, T.; Voelkl, A. (Department of Zoology I, University of Heidelberg (Germany))

    1991-04-01

    Structural and functional alterations in hepatocytes of the European eel, Anguilla anguilla, following a 4-week-exposure to 5, 50, and 250 micrograms/liter dinitro-o-cresol (DNOC) were investigated by means of electron microscopy and biochemistry and compared to liver pathology in eels exposed to the chemical spill into the Rhine river at Basle in November 1986. Whereas phenological parameters (growth, condition factor) are unaffected, ultrastructural and biochemical alterations are detectable at greater than or equal to 50 and 5 micrograms/liter DNOC, respectively. Structural modifications include: rounding-up of the nuclei; fractionation and reduction of the rough endoplasmic reticulum; proliferation of the smooth endoplasmic reticulum (SER), mitochondria, peroxisomes, and lysosomes; bundles of rod-shaped SER profiles; annulate lamellae; membrane whorls within mitochondria; crystallization of the peroxisomal matrix and glycogen bodies; glycogen depletion and lipid augmentation. Structural changes can be correlated to an increase in hepatic lipid and protein contents as well as stimulation of mitochondrial (cytochrome c oxidase), peroxisomal (catalase, allantoinase, uricase), lysosomal (arylsulfatase), and microsomal (esterase) enzymes. An increase in NADPH-cytochrome c reductase and cytochrome P450 as well as UDP-glucuronyltransferase and arylsulfotransferase activities in the microsomal fraction document an induction of hepatic biotransformation as a functional correlate to SER proliferation. Maximum inducibility of biotransformation enzymes at 50 micrograms/liter indicates a biphasic, concentration-dependent reaction of eel liver. Comparison of DNOC-induced effects with liver pathology in eel exposed to the chemical spill in 1986 reveals striking similarities so that DNOC may not be excluded as a possible factor in the fish kill in the Rhine river.

  18. A century of research on the larval distributions of the Atlantic eels: a re-examination of the data

    DEFF Research Database (Denmark)

    Miller, Michael J.; Bonhommeau, Sylvain; Munk, Peter

    2015-01-01

    The spawning areas of the Atlantic freshwater eels were discovered about a century ago by the Danish scientist Johannes Schmidt who after years of searching found newly hatched larvae of the European eel, Anguilla anguilla, and the American eel, Anguilla rostrata, in the southern Sargasso Sea...

  19. The Giant Mottled Eel, Anguilla marmorata, Uses Blue-Shifted Rod Photoreceptors during Upstream Migration

    OpenAIRE

    Wang, Feng-Yu; Fu, Wen-Chun; Wang, I-Li; Yan, Hong Young; Wang, Tzi-Yuan

    2014-01-01

    Catadromous fishes migrate between ocean and freshwater during particular phases of their life cycle. The dramatic environmental changes shape their physiological features, e.g. visual sensitivity, olfactory ability, and salinity tolerance. Anguilla marmorata, a catadromous eel, migrates upstream on dark nights, following the lunar cycle. Such behavior may be correlated with ontogenetic changes in sensory systems. Therefore, this study was designed to identify changes in spectral sensitivity ...

  20. Reproduction of European Eel in Aquaculture (REEL)

    DEFF Research Database (Denmark)

    Tomkiewicz, Jonna; Tybjerg, Lars; Støttrup, Josianne

    Project aim: Enhance methods and technology applied to produce and culture European eel larvae as basis for the development of a future self-sustained eel aquaculture. Background: The severe decline of the European eel stock calls for conservation measures including national eel management plans...... and establishment of a self-sustained eel aquaculture. In 2005, the National Institute of Aquatic Resources at the Technical University of Denmark (DTU Aqua), the Faculty of Life Sciences at Copenhagen University (KU-Life) and the eel aquaculture industry started to build up a research and technology platform...... feeding. The results were in particular promising because they evidenced that methods successfully applied to Japanese eel has a potential for application also to the European eel. ROE II and III were supported by the Ministry of Food, Agriculture and Fisheries and the European Commission through...

  1. Maternally transferred dioxin-like compounds can affect the reproductive success of European eel.

    Science.gov (United States)

    Foekema, Edwin M; Kotterman, Michiel; de Vries, Pepijn; Murk, Albertinka J

    2016-01-01

    Reported concentrations of dioxin-like compounds accumulated in the European eel (Anguilla anguilla) were used to perform a risk assessment for eel larval survival, taking into account a modeled amplification of tissue concentrations with a factor of 1.33 during spawning migration. The calculated concentrations of dioxin-like compounds finally deposited in the eggs were compared with the internal effect concentrations for survival of early life stages of the European eel; these concentrations, by lack of experimental data, were estimated from a sensitivity distribution based on literature data by assuming that eel larvae are among the 10% most sensitive teleost fish species. Given concentrations of dioxin-like contaminants and assuming a relatively high sensitivity, it can be expected that larvae from eggs produced by eel from highly contaminated locations in Europe will experience increased mortality as a result of maternally transferred dioxin-like contaminants. As historical persistent organic pollutant concentrations in eel tissue were higher, this impact must have been stronger in the past. Potential effects of other compounds or effects on the migration, condition, and fertility of the parental animals were not taken into account. It is important to further study the overall impact of contaminants on the reproductive success of the European eel as this may have been underestimated until now. © 2015 SETAC.

  2. Treatment of trichodiniasis in eel ( Anguilla anguilla ) reared in recirculation systems in Denmark : alternatives to formaldehyde

    DEFF Research Database (Denmark)

    Madsen, H.C.K.; Buchmann, Kurt; Mellergaard, Stig

    2000-01-01

    Treatment of trichodiniasis in recirculation eel farms using formalin (37%) has been found insufficient. We have screened 30 different chemical substances for efficacy against natural infections with trichodinids (Trichodina jadranica) on skin and gills of eels. The following substances showed hi...

  3. Evaluation of captive needle stunning of farmed eel (Anguilla anguilla L.): suitability for humane slaughter

    NARCIS (Netherlands)

    Lambooij, E.; Vis, van de J.W.; Kloosterboer, R.J.; Pieterse, C.

    2002-01-01

    In the study, 53 eels with a live weight of 700 to 800 g were restrained and equipped with EEG and ECG electrodes before stunning. The eels were mechanically stunned by a captive needle pistol using a shooting pressure of 8 bar and an air injection of 3 bar during 1.5 s. The behaviour was observed

  4. Stegodexamene anguillae (Digenea: Lepocreadiidae), an intestinal parasite of eels (Anguilla spp.) in New Caledonia

    Czech Academy of Sciences Publication Activity Database

    Moravec, František; Justine, J.-L.

    2007-01-01

    Roč. 100, č. 5 (2007), s. 1047-1051 ISSN 0932-0113 R&D Projects: GA ČR(CZ) GA524/06/0170; GA MŠk LC522 Institutional research plan: CEZ:AV0Z60220518 Keywords : Stegodexamene * Anguilla * New Caledonia Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 1.512, year: 2007

  5. LEUKOCYTE DIFFERENTIAL OF ANGUILLID EEL, Anguilla bicolor McClelland, EXPOSED TO VARIED SALINITIES

    Directory of Open Access Journals (Sweden)

    Fita Fatimah

    2017-06-01

    Full Text Available The anguillid eel is a catadromous eel capable of inhabiting freshwater growth habitat and seawater spawning habitat throughout their life cycle. At the juvenile to mature stage, they inhabit freshwater then migrate to marine water to spawn. Changes in salinity, which is one of the stressful environmental factors for the eel, affect their physiological condition by increasing the leukocytes number. This increase is an adaptation method to improve their immune system as a response to salinity change. This study intended to evaluate the leukocyte differential of anguillid eel (Anguilla bicolor McClelland exposed to various salinities. This research applied a Completely Randomized Design. The treatment was three levels of saline media including 4 ppt, 15 ppt, and 30 ppt with five replicates. The independent variable was the different salinity, and the dependent variable was the leukocyte differential. The parameters measured consisted of the different percentage of neutrophils, lymphocytes, monocytes, and eosinophils in which the measurements administered after two months of the eel exposure. We analyzed the data with ANOVA at the confidence level of 95%. The results showed that exposure of salinity significantly affected the percentage of leukocyte differential (P < 0.05. The increase in salinity decreased the neutrophils and monocytes, but increased the lymphocytes, and showed no effect on eosinophils.

  6. MACROPARASITE COMMUNITY AND ASYMMETRY OF THE YELLOW EEL ANGUILLA ANGUILLA IN SALSES-LEUCATE LAGOON, SOUTHERN FRANCE

    Directory of Open Access Journals (Sweden)

    FAZIO G.

    2005-10-01

    Full Text Available European eel parasites, in particular invasive species, are suspected to have a strong influence on the population dynamics of their host. The aim of this work was to study the relationship between parasitic fauna of yellow eels caught at Salses-Leucate lagoon and the fluctuating asymmetry (FA of some functional bilateral traits: pectoral fins, eyes and otoliths. Epidemiological distance matrices and FA distance matrices were calculated on the basis of the Euclidian distances between each pair of eel and were then compared with a Mantel test in order to establish if there was a relationship between parasitism and FA. Our results revealed different morphological characteristics between eels caught at different dates; only otoliths were found asymmetric. The parasite richness was of 10 species, 1 Nematoda, 1 Acanthocephala, 1 Monogenea and 7 Digenea. We failed to find a significant relationship between asymmetry and parasitism, except for parasites found in the stomach. We discussed the results in the light of the eel life cycle, the specificity of parasite - eel systems and the impact of parasites on the host physiology.

  7. Heterogeneity among isolates of Vibrio vulnificus recovered from eels ( Anguilla anguilla ) in Denmark

    DEFF Research Database (Denmark)

    Høi, L.; Dalsgaard, Inger; DePaola, A.

    1998-01-01

    are genetically heterogenous as shown by ribotyping, Ribotyping also showed that the same isolates map persist in an eel farm and cause recurrent outbreaks, Phage typing did not correlate with ribotyping or serotyping. However, we observed that 26 of 28 isolates, which mere not susceptible to any of the phages......The findings of this study demonstrate that Vibrio vulnificus isolates recovered from diseased eels in Denmark are heterogeneous as shown by O serovars, capsule types, ribotyping, phage typing, and plasmid profiling, The study: includes 85 V. vulnificus isolates isolated from the gills, intestinal...

  8. The eel immune system: present knowledge and the need for research

    DEFF Research Database (Denmark)

    Nielsen, Michael Engelbrecht; Esteve-Gassent, M. D.

    2006-01-01

    The European eel, Anguilla anguilla, is one of the most important warm water fish species cultured in southern Europe and the Mediterranean as well as in northern countries including Germany, the Netherlands and Denmark. The Japanese eel, A. japonica, is an important cultured fish in several...... immune responses. This review summarizes the present knowledge relating to the eel immune system and includes new data....

  9. Comparative study about the effects of pollution on glass and yellow eels (Anguilla anguilla) from the estuaries of Minho, Lima and Douro Rivers (NW Portugal).

    Science.gov (United States)

    Gravato, Carlos; Guimarães, Laura; Santos, Joana; Faria, Melissa; Alves, Anabela; Guilhermino, Lúcia

    2010-05-01

    The health status of eels (Anguilla anguilla) developing in three estuaries of the NW Portuguese coast with different types and levels of pollution was compared in relation to morphometric parameters, Fulton condition index (F index) and several biomarkers. Relatively to the reference population, glass eels from the Lima estuary had lower weight and length, cholinesterase (ChE) and lactate dehydrogenase (LDH) inhibition, and lower levels of some anti-oxidant parameters, while yellow eels also showed a decreased F index, and increased Na(+)/K(+)-ATPase and lipid peroxidation (LPO) levels. Relatively to the reference population, glass eels from the Douro estuary had increased Na(+)/K(+)-ATPase and glutathione-S-transferase activities and LDH inhibition, while yellow eels also had ChE inhibition and increased LPO. Overall, these results indicate that eels from polluted estuaries showed a poor health status than those from a reference estuary, and that adverse effects become more pronounced after spending several years in polluted estuaries. Copyright 2009 Elsevier Inc. All rights reserved.

  10. Recapture rate, growth and sex of stocked cultured eels Anguilla anguilla (L.)

    DEFF Research Database (Denmark)

    Pedersen, Michael Ingemann

    1998-01-01

    .2% at the open coast. Length increment was estimated to be between 2.5 and 6.5 cm annually. The sex ratio (female/male) of yellow eels increased in subsequent years of recaptures, possibly as a result of environmental sex determination following release. The use of Alcian blue for a long-term marking experiment...

  11. Fall diel diet composition of American eel (Anguilla rostrata) in a tributary of the Hudson River, New York, USA

    Science.gov (United States)

    Waldt, Emily M.; Abbett, Ross; Johnson, James H.; Dittman, Dawn E.; McKenna, James E.

    2013-01-01

    American eel (Anguilla rostrata), a once common species, is now in decline throughout much of its native range in North America. There is little information on the role of American eel in river food webs. A better understanding of the diet and ecological role of American eel will help in the conservation of this important species. During autumn 2009, eel and aquatic invertebrate samples were collected from Hannacroix Creek, a tributary of the Hudson River, in Albany and Greene counties, New York, USA. Eel diet was analyzed by the eel size and time period (day or night). A high proportion of eel stomachs were empty (73%). Eel diets varied among size classes and day and night feeding periods (p = 0.001). Diet overlap was significant between small and medium eels caught both during the day (α = 0.71) and at night (α = 0.84). Nocturnal diet and nocturnal invertebrate samples were similar (α = 0.65), indicating a preference for bottom feeding during the night. Mayfly nymphs were the major prey consumed in each period by all size classes. Among eels that fed, night-feeding eels had the greatest stomach weight (as a percent of total body weight). The swim-bladder parasite, Anguillicoloides crassus, was also observed in eels of all size classes with nearly 50% afflicted.

  12. Qualitative assessment of the diet of European eel larvae in the Sargasso Sea resolved by DNA barcoding.

    Science.gov (United States)

    Riemann, Lasse; Alfredsson, Hanna; Hansen, Michael M; Als, Thomas D; Nielsen, Torkel G; Munk, Peter; Aarestrup, Kim; Maes, Gregory E; Sparholt, Henrik; Petersen, Michael I; Bachler, Mirjam; Castonguay, Martin

    2010-12-23

    European eels (Anguilla anguilla) undertake spawning migrations of more than 5000 km from continental Europe and North Africa to frontal zones in the Sargasso Sea. Subsequently, the larval offspring are advected by large-scale eastward ocean currents towards continental waters. However, the Sargasso Sea is oligotrophic, with generally low plankton biomass, and the feeding biology of eel larvae has so far remained a mystery, hampering understanding of this peculiar life history. DNA barcoding of gut contents of 61 genetically identified A. anguilla larvae caught in the Sargasso Sea showed that even the smallest larvae feed on a striking variety of plankton organisms, and that gelatinous zooplankton is of fundamental dietary importance. Hence, the specific plankton composition seems essential for eel larval feeding and growth, suggesting a linkage between eel survival and regional plankton productivity. These novel insights into the prey of Atlantic eels may furthermore facilitate eel larval rearing in aquaculture, which ultimately may replace the unsustainable use of wild-caught glass eels.

  13. EVIDENCE SUPPORTING THE OCCURRENCE AND THE ECOLOGICAL IMPLICATION OF GIANT MOTTLED EEL, ANGUILLA MARMORATA (ACTINOPTERYGII: ANGUILLIFORMES: ANGUILLIDAE), FROM SABAH, BORNEO ISLAND

    National Research Council Canada - National Science Library

    Li Lian Wong; Siti Raudah Abdul Kadir; Rabi Atun Adawiah Abdullah; Charlie Albert Lasuin; Kok Onn Kwong; Takaomi Arai

    2017-01-01

    .... Two anguillid eels found in Sabah, Borneo Island, were firstly identified as Anguilla marmorata Quoy et Gaimard, 1824 using morphological analysis and further analysis of mitochondrial 16S ribosomal RNA (16S rRNA...

  14. Diel periodicity and chronology of upstream migration in yellow-phase American eels (Anguilla rostrata)

    Science.gov (United States)

    Aldinger, Joni L.; Welsh, Stuart A.

    2017-01-01

    Yellow-phase American eel (Anguilla rostrata) upstream migration is temporally punctuated, yet migration chronology within diel time periods is not well-understood. This study examined diel periodicity, chronology, and total length (TL) of six multi-day, high-count (285–1,868 eels) passage events of upstream migrant yellow-phase American eels at the Millville Dam eel ladder, lower Shenandoah River, West Virginia during 2011–2014. We categorized passage by diel periods (vespertine, nocturnal, matutinal, diurnal) and season (spring, summer, late summer/early fall, fall). We depicted passage counts as time-series histograms and used time-series spectral analysis (Fast Fourier Transformation) to identify cyclical patterns and diel periodicity of upstream migration. We created histograms to examine movement patterns within diel periods for each passage event and fit normal mixture models (2–9 mixtures) to describe multiple peaks of passage counts. Periodicity of movements for each passage event followed a 24-h activity cycle with mostly nocturnal movement. Multimodal models were supported by the data; most modes represented nocturnal movements, but modes at or near the transition between twilight and night were also common. We used mixed-model methodology to examine relationships among TL, diel period, and season. An additive-effects model of diel period + season was the best approximating model. A decreasing trend of mean TL occurred across diel movement periods, with the highest mean TL occurring during fall relative to similar mean values of TL for spring, summer, and late summer/early fall. This study increased our understanding of yellow-phase American eels by demonstrating the non-random nature of their upstream migration.

  15. Solvent and extraction methods effects on the quality of eel (Anguilla bicolor) oil

    Science.gov (United States)

    Sasongko, H.; Efendi, N. R.; Budihardjo, A.; Farida, Y.; Amartiwi, T.; Rahmawati, A. A.; Wicaksono, A.; Sugiyarto

    2017-01-01

    Eel (Anguilla bicolor) is a general fish consumption in many countries, especially Japan, China, Germany, and France. Besides its vitamin rich, eel oil is also known to contain fatty acids that are necessary for pharmaceutical purposes and as food a supplement. This research was aimed to evaluate the quality of eel oil by different solvent and extraction methods. In this study, fresh eels were extracted using maceration and reflux methods.Chloroform was used as the solvent in the maceration while water used in the reflux method. The oil quality was examined based on the Official Methods of Analysis of the Association of Official Analytical Chemist (AOAC).The result showed that the yield of eel oil using maceration method was 5.44% ± 0.64 with a specific gravity of 0.915 g/mL, while reflux method obtained the yield of 5.33 % ± 0.84 and specific gravity of 0.8575 g/mL. The physicochemical parameters of oil quality used in this study were acid, peroxide, saponification, and iodine value. The maceration method obtained the acid value of 17.389 mgKOH/g, the peroxide value of 7.021meqO2/kg, the saponification value of 111.16mgKOH/g, and the iodine value of 65.14 WIJS. While the reflux method produced the acid value of 9.116 mgKOH/g, the peroxide value of 6.088 meqO2/kg, the saponification value of 70 mgKOH/g, and the iodine value of 87.74 WIJS.

  16. Association between trichodiniasis in eel ( Anguilla anguilla ) and water quality in recirculation systems

    DEFF Research Database (Denmark)

    Madsen, H.C.K.; Buchmann, K.; Mellergaard, Stig

    2000-01-01

    Association between various water quality parameters and the infection level of Trichodina jadranica in cultured eels were examined in nine recirculation farms in Denmark. Production units suffering from trichodiniasis (n = 4) had relatively high contents of organic dry matter (13-65 mg l(-1)), low...... of the effect of water parameters on the infection level were conducted in two production units suffering from frequent outbreaks of trichodiniasis. In one production unit, the high and highly varying content of organic dry matter (21- 83 mg l(-1)) was significantly and positively correlated (r = 0.37, p ....001) to the intensity of infection (1-150 trichodinids per fish) during a 19-day period. In the other production unit (with a low and stabile content of organic dry matter (2-7 mg l(-1))), no correlation was seen neither between a high and highly varying concentration of nitrate (635-1104 mg NO3 l(-1)) and intensity...

  17. Evaluation of surgical implantation of electronic tags in European eel and effects of different suture materials

    DEFF Research Database (Denmark)

    Thorstad, Eva B.; Økland, Finn; Westerberg, Håkan

    2013-01-01

    Effects of implanting data-storage tags in European eel, Anguilla anguilla, and the suitability of different suture materials (braided permanent silk, permanent monofilament, absorbable and absorbable antibacterial) were examined. The tags consisted of an electronic unit and three floats on a wire......, making them flexible and able to follow the swimming movements of the eel. No mortality occurred, and tagged fish did not differ from the control fish in growth. Sutures were shed or dissolved slowly. After 4 weeks, there was no difference among the groups in the proportion of sutures left. After 6....... Antibacterial treatment had no effect on inflammation or healing rates. After 6 months, the tag started to become expelled through the incision in five fish (12%). The internal reaction appeared stronger around the floats, suggesting that the coating material of the floats created a tissue reaction, which...

  18. Piscivory and trophic position of Anguilla anguilla in two lakes: importance of macrozoobenthos density

    NARCIS (Netherlands)

    Dorner, H.; Skov, C.; Berg, S.; Schulze, T.; Beare, D.J.; Velde, van der G.

    2009-01-01

    The feeding habits of the European eel Anguilla anguilla (> 300 mm total length, L-T) were compared in two lakes of different environmental state: Lake Gro ss er Vatersee (LGV), Germany (clear water, mesotrophic and submerged macrophytes), and Lake Vallum (LV), Denmark (turbid, eutrophic and no

  19. Loss of European silver eel passing a hydropower station

    DEFF Research Database (Denmark)

    Pedersen, Michael Ingemann; Jepsen, Niels; Aarestrup, Kim

    2012-01-01

    The aim of this study was to assess escapement success of silver eels, Anguilla anguilla (L.), in a lowland river while passing a reservoir and a hydropower station. It was hypothesized that passage success would be lowest at the hydropower station and that survival and migration speed would...... be highest in the free-flowing river section upstream the reservoir. Forty-five female silver eels 56–86 cm in length were tagged with acoustic transmitters and released in November 2006. Their migration was monitored via automatic listening stations (ALS) in various sections of the river, covering a total...

  20. Whether European eel leptocephali use the Earth's magnetic field to guide their migration remains an open question.

    Science.gov (United States)

    Durif, Caroline M F; Bonhommeau, Sylvain; Briand, Cédric; Browman, Howard I; Castonguay, Martin; Daverat, Francoise; Dekker, Willem; Diaz, Estibaliz; Hanel, Reinhold; Miller, Michael J; Moore, Andy; Paris, Claire B; Skiftesvik, Anne Berit; Westerberg, Håkan; Wickström, Håkan

    2017-09-25

    European eels (Anguilla anguilla) migrate between the southwestern Sargasso Sea and the European and Mediterranean coasts. In a recent paper in Current Biology, Naisbett-Jones et al.[1] claim to "provide the first evidence that they [eels] derive positional information from the Earth's magnetic field" and that this information guides their migration. The evidence reported by Naisbett-Jones et al.[1] in support of this conclusion was derived from eels collected in the Severn River (UK), approximately 50 km upstream of the estuary (i.e. not "in the Severn Estuary" as stated by the authors). Eels collected this far into rivers are benthic and fully adapted to freshwater; that is, they are late-stage glass eels (∼ 2 years old), not the pelagic leptocephalus (larval) life stage that actually undertakes the trans-Atlantic migration. The entire interpretive framework for the Naisbett-Jones et al.[1] study rests on the assumption that the behaviour of these late-stage freshwater glass eels, and their responses to magnetic fields, can be used as a proxy for the responses of eel leptocephali. The authors present no evidence in support of this key assumption. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  1. Eels:Contaminant cocktails pinpointing environmental contamination

    OpenAIRE

    Belpaire, Claude; Goemans, Geert

    2008-01-01

    There is growing concern that insufficient somatic and health conditions of silver European eels (Anguilla anguilla) emigrating from European waters to oceanic spawning areas might be a key causative factor in the decline of the stock. One factor that could contribute to deterioration in the status of eels is high contaminant accumulation in their body. Contaminants may affect lipid metabolism and result in lower energy stores. A high body burden of contaminants and low energy stores might be...

  2. Molecular characterization of Aeromonas species isolated from farmed eels (Anguilla japonica).

    Science.gov (United States)

    Yi, Seung-Won; You, Myung-Jo; Cho, Ho-Seong; Lee, Chang-Seop; Kwon, Joong-Ki; Shin, Gee-Wook

    2013-05-31

    Seventy Aeromonas strains were identified by phylogenetic analysis using housekeeping genes (gyrB and rpoD) in order to investigate etiological agents for aeromoniasis in farmed eels (Anguilla japonica). The phylogenetic analysis showed that Aeromonas aquariorum (n=22, 31.4%) was the predominant species among the investigated eel strains, followed by Aeromonas caviae (n=16, 22.9%), A. veronii (n=13, 18.6%), A. hydrophila (n=12, 17.1%), A. jandaei (n=4, 5.7%), A. media (n=2, 2.9%), and A. trota (n=1, 1.4%). The potential virulence of the present strains was estimated by performing PCR assays using the following seven virulence genes: cytotoxic enterotoxin (act), two cytotonic enterotoxins (alt and ast), glycerophospholipid:cholesterol acyltransferase (gcaT), DNase (exu), lipase (lip), and flagellin (fla). The detection rates of act, alt, ast, gcaT, exu, lip, and fla among all 70 strains were 91.4%, 55.7%, 27.1%, 97.1%, 95.7%, 100%, and 98.6%, respectively. In genotyping of enterotoxin genes, act(+)/alt(+)/ast(+), act(+)/alt(+)/ast(-), and act(+)/alt(-)/ast(-) genotypes were prevalent in A. hydrophila (8/12 strains), A. aquariorum (13/22 strains), and A. caviae (14/16 strains), respectively, suggesting a high heterogeneity among Aeromonas species. In this study, A. aquariorum, which has been an unrecorded species in Korea, can be an etiological agent for aeromoniasis of eel. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Organophosphorus flame retardants in the European eel in Flanders, Belgium: Occurrence, fate and human health risk.

    Science.gov (United States)

    Malarvannan, Govindan; Belpaire, Claude; Geeraerts, Caroline; Eulaers, Igor; Neels, Hugo; Covaci, Adrian

    2015-07-01

    The present study investigated the levels, profiles and human health risk of organophosphorus flame retardants and plasticizers (PFRs) in wild European eels (Anguilla anguilla) from freshwater bodies in the highly populated and industrial Flanders region (Belgium). Yellow eels (n=170) were collected at 26 locations between 2000 and 2009 and for each site, muscle samples of 3-10 eels were pooled and analyzed (n=26). Muscle lipid percentages varied widely between 2.4% and 21%, with a median value of 10%. PFRs were detected in all pooled samples in the order of tris-2-chloroisopropyl phosphate (TCIPP)>triphenyl phosphate (TPHP)>2-ethylhexyl diphenyl phosphate (EHDPHP)>tris-2-butoxyethyl phosphate (TBOEP)>tris-2-chloroethyl phosphate (TCEP)>tris-1,3-dichloro-2-propyl phosphate (TDCIPP). The median sum PFR concentration for all 26 sites was 44 ng/g lw (8.4 ng/g ww), and levels ranged between 7.0 and 330 ng/g lw (3.5 and 45 ng/g ww). Levels and profiles of PFRs in eels showed that sampling locations and river basin catchments are possible drivers of spatial variation in the aquatic environment. Median PFR concentrations were lower than those of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs). No correlation was observed between the PFR concentrations and lipid contents, suggesting that the accumulation of PFRs is not primarily associated with lipids. Human exposure to PFRs, due to consumption of wild eels, seems to be of minor importance compared to other potential sources, such as inhalation and ingestion of indoor dust. Nevertheless, considering the very limited data available on PFRs in human dietary items and their expected increasing use after the phase out of PBDEs and HBCDs, further investigations on PFRs in biota and human food items are warranted. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Umur glas eel (Anguilla spp. yang masuk muara Sungai Progo Yogyakarta

    Directory of Open Access Journals (Sweden)

    Agung Budiharjo

    2017-03-01

    Full Text Available The leptocephalus drift with sea currents and moving from spawning area into coastal area near mouth of Progo River. In thecoastal area, leptocephalus metamorfosed into glass eel, after that glass eel migrated to river. The aims of this research were to estimate glass eels age and predict hatching dates. Glass eels sampled on new moon during Februari 2007-Mei 2009 at mouth of Progo River.Glass eel ages estimated using their otolith micro structure. Hatching dates predicted with back calculation of glass eels age. We collected 1.082 glass eels. The ages of glass eel at recruit ranged from 58 to 190 days, and divided into 5 age groups. Glass eels are migrated to river hatched on a "new moon" from July to January. Glass eels are migrated to river during October-January hatched during July-October. Glass eels are migrated to river during February-Juny hatched during November-January.

  5. Quality attributes of farmed eel (Anguilla anguilla) stored under air, vacuum and modified atmosphere packaging at 0 degrees C.

    Science.gov (United States)

    Arkoudelos, John; Stamatis, Nikolaos; Samaras, Fotis

    2007-01-01

    The shelf life of fresh eel in various packaging conditions of atmospheric air, vacuum and modified atmosphere packaging (MAP) (40% CO(2), 30% N(2) and 30% O(2)) at 0 degrees C was investigated. All raw eel samples received acceptable sensory scores during the first 11+/-1 days of storage in atmospheric air, 11+/-1 days of storage in vacuum and finally 18+/-1 days of storage in MAP conditions. Using the microbial quality indicators the shelf life of eel packed in air, vacuum and MAP was estimated to be more than 18, 28 and 34 days, respectively. The main spoilage microorganisms under MAP conditions were lactic acid producing bacteria followed by Shewanella spp., pseudomonads, Enterobacteriaceae and yeasts. Chemical data revealed that pH, ammonia, glucose and lactate examinations might not be useful for monitoring eel quality differences.

  6. THE CONTRIBUTION OF SPRINGTIME AND AUTUMN GLASS EELS (ANGUILLA ANGUILLA TO STOCK : RESULTS BASED ON OTOLITH MORPHOMETRY.

    Directory of Open Access Journals (Sweden)

    BRIAND C.

    2003-07-01

    Full Text Available A double mark, called a transition ring, or elver mark, was identifiable in light microscopy on otoliths of young yellow eels. In the Vilaine watershed, the radius of this mark decreased from 178 μm in yellow eels corresponding to glass eels arriving in autumn 1997 to 163 μm in yellow eels arriving in spring 1998. The mean transition ring radius of the freshwater eel population in the Vilaine river had an intermediate value between spring and autumn recruits. This implies that it consisted of a mixture of spring and autumn recruits. In the Vilaine estuary and the Frémur populations, the mean radius of the transition rings was close to the autumn one. The springtime recruits formed 68 % of freshwater and 15 % of estuarine population in the Vilaine for the 1998 cohort. This result was in sharp contrast with the available assessments of recruitment, which both in estuary and in the fluvial part of the watershed, were dominated by spring recruits. This contrast is possibly the consequence of density-dependent mortality, which would have been particularly important in springtime for glass eels whose migration was inhibited by the dam.

  7. Observations on nematodes from the Indonesian shortfin eel Anguilla bicolor bicolor McClelland in India, including a revalidation of Heliconema ahiri Karve, 1941 (Physalopteridae)

    Czech Academy of Sciences Publication Activity Database

    Moravec, František; Sheeba, S.; Kumar, A. B.

    2013-01-01

    Roč. 58, č. 4 (2013), s. 496-503 ISSN 1230-2821 R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:60077344 Keywords : Parasitic nematode * Heliconema * Procamallanus * Spirocamallanus * freshwater eel * Anguilla bicolor bicolor * Kerala * India Subject RIV: EA - Cell Biology Impact factor: 0.965, year: 2013

  8. Evaluating the adaptive potential of the European eel: is the immunogenetic status recovering?

    Directory of Open Access Journals (Sweden)

    Miguel Baltazar-Soares

    2016-04-01

    Full Text Available The recent increased integration of evolutionary theory into conservation programs has greatly improved our ability to protect endangered species. A common application of such theory links population dynamics and indices of genetic diversity, usually estimated from neutrally evolving markers. However, some studies have suggested that highly polymorphic adaptive genes, such as the immune genes of the Major Histocompatibility Complex (MHC, might be more sensitive to fluctuations in population dynamics. As such, the combination of neutrally- and adaptively-evolving genes may be informative in populations where reductions in abundance have been documented. The European eel (Anguilla anguilla underwent a drastic and well-reported decline in abundance in the late 20th century and still displays low recruitment. Here we compared genetic diversity indices estimated from neutral (mitochondrial DNA and microsatellites and adaptive markers (MHC between two distinct generations of European eels. Our results revealed a clear discrepancy between signatures obtained for each class of markers. Although mtDNA and microsatellites showed no changes in diversity between the older and the younger generations, MHC diversity revealed a contemporary drop followed by a recent increase. Our results suggest ongoing gain of MHC genetic diversity resulting from the interplay between drift and selection and ultimately increasing the adaptive potential of the species.

  9. Oceanic and local environmental conditions as forcing mechanisms of the glass eel recruitment to the southernmost European estuary

    Science.gov (United States)

    Arribas, Carmen; Fernández-Delgado, Carlos; Oliva-Paterna, Francisco J.; Drake, Pilar

    2012-07-01

    The main oceanic and local environmental traits forcing the glass eel Anguilla anguilla (L., 1758) recruitment to the southernmost European estuary, the Guadalquivir (SW Spain), were studied during nine successive migration seasons (June 1997-December 2006) using a fishery-independent experimental survey at three sampling sites in the estuary. A clear seasonal pattern was observed: density was highest between late autumn and spring with two migration peaks, and lowest during summer. Short-term (inter-month) changes in glass eel density were partially driven by local environmental variables, such as estuarine turbidity, local rainfall and water temperature. Long-term (inter-annual) changes were positively correlated with oceanic factors related to recruitment success (NAO index and primary production at the spawning area) as well as local environmental factors (westerly and southerly wind mixing indices and rainfall). Spatial changes in glass eel density within the estuary depended on tidal and light situations although maximum densities were mainly observed at diurnal and/or nocturnal flood tides. Although the decrease in the abundance of European glass eels has been widely known since the 1980s, during this study there was no evidence of a declining trend, probably because of an insufficiently long time series.

  10. The temperature challenges on cardiac performance in winter-quiescent and migration-stage eels Anguilla anguilla

    DEFF Research Database (Denmark)

    Methling, C.; Steffensen, J. F.; Skov, Peter Vilhelm

    2012-01-01

    The present study was undertaken to examine cardiac responses to some of the temperature challenges that eels encounter in their natural environment. The contractile properties of ventricular muscle was studied on electrically paced tissue strips after long term acclimation at 0 °C, 10 °C, or 20 °C......, temperature-dependent response, but did not influence twitch duration. This suggests that adrenaline acts as an agent in maintaining an adequate contractile force following temperature challenges. A significant increased relative ventricular mass was observed in 0 °C and 10 °C-acclimated eels compared to 20...... °C-acclimated, which suggests that at low temperatures, eels secure cardiac output by heart enlargement. Inhibition of specific sarcolemmal Ca 2 + channels by selective drug treatment revealed that, depending on temperature, L-type channels is the major entry site, but also that reverse-mode Na +/Ca...

  11. Welfare aspects of live chilling and freezing of farmed eel (Anguilla anguilla L.): neurological and behavioural assessment

    NARCIS (Netherlands)

    Lambooij, E.; Vis, van de J.W.; Kloosterboer, R.J.; Pieterse, C.

    2002-01-01

    Firstly, 19 eels with an average live weight of 758±44 g were restrained and equipped with EEG, ECG electrodes and a temperature sensor inside the body. Then, they were placed in the ice water. Indices for the induction of unconsciousness and insensibility were the appearance of theta and delta

  12. Shark predation on migrating adult american eels (Anguilla rostrata) in the Gulf of St. Lawrence

    DEFF Research Database (Denmark)

    Béguer-Pon, Mélanie; Benchetrit, José; Castonguay, Martin

    2012-01-01

    to identify the eel predators, we compared their vertical migratory behavior with those of satellite-tagged porbeagle shark and bluefin tuna, the only endothermic fishes occurring non-marginally in the Gulf of St. Lawrence. We accurately distinguished between tuna and shark by using the behavioral criteria...... generated by comparing the diving behavior of these two species with those of our unknown predators. Depth profile characteristics of most eel predators more closely resembled those of sharks than those of tuna. During the first days following tagging, all eels remained in surface waters and did not exhibit...... itself may contribute to increasing the eel's susceptibility to predation, we discuss evidence suggesting that predation of silver-stage American eels by porbeagle sharks may represent a significant source of mortality inside the Gulf of St. Lawrence and raises the possibility that eels may represent...

  13. Genomic Sequence of a Ranavirus Isolated from Short-Finned Eel (Anguilla australis)

    DEFF Research Database (Denmark)

    Subramaniam, Kuttichantran; Toffan, Anna; Cappellozza, Elisabetta

    2016-01-01

    The short-finned eel ranavirus (SERV) was isolated from short-finned eel imported to Italy from New Zealand. Phylogenomic analyses revealed that SERV is a unique member of the genus Ranavirus, family Iridoviridae, branching at the base of the tree near other fish ranaviruses.......The short-finned eel ranavirus (SERV) was isolated from short-finned eel imported to Italy from New Zealand. Phylogenomic analyses revealed that SERV is a unique member of the genus Ranavirus, family Iridoviridae, branching at the base of the tree near other fish ranaviruses....

  14. Oceanic fronts in the Sargasso Sea control the early life and drift of Atlantic eels

    DEFF Research Database (Denmark)

    Munk, Peter; Hansen, Michael Møller; Maas, Gregory E.

    2010-01-01

    Anguillid freshwater eels show remarkable life histories. In the Atlantic, the European eel (Anguilla anguilla) and American eel (Anguilla rostrata) undertake extensive migrations to spawn in the oceanic Sargasso Sea, and subsequently the offspring drift to foraging areas in Europe and North...... America, first as leaf-like leptocephali larvae that later metamorphose into glass eels. Since recruitment of European and American glass eels has declined drastically during past decades, there is a strong demand for further understanding of the early, oceanic phase of their life cycle. Consequently...... to the eastward flowing Subtropical Counter Current indicates that these larvae could follow a shorter, eastward route towards the Azores and Europe. The findings emphasize the significance of oceanic physical–biological linkages in the life-cycle completion of Atlantic eels....

  15. Molecular markers of oocyte differentiation in European eel during hormonally induced oogenesis.

    Science.gov (United States)

    Rojo-Bartolomé, Iratxe; Martínez-Miguel, Leticia; Lafont, Anne-Gaëlle; Vílchez, M Carmen; Asturiano, Juan F; Pérez, Luz; Cancio, Ibon

    2017-09-01

    Reproduction in captivity is a key study issue in Anguilla anguilla as a possible solution for its dwindling population. Understanding the mechanisms controlling the production of ribosomal building blocks during artificially induced oocyte maturation could be particularly interesting. Transcription levels of ribosomal biogenesis associated genes could be used as markers to monitor oogenesis. Eels from the Albufera Lagoon were injected with carp pituitary extract for 15weeks and ovaries in previtellogenic (PV) stage (non-injected), in early-, mid-, late-vitellogenesis (EV, MV, LV), as well as in migratory nucleus stage (MN) were analysed. 5S rRNA and related genes were highly transcribed in ovaries with PV oocytes. As oocytes developed, transcriptional levels of genes related to 5S rRNA production (gtf3a), accumulation (gtf3a, 42sp43) and nucleocytoplasmic transport (rpl5, rpl11) and the 5S/18S rRNA index decreased (PV>EV>MV>LV>MN). On the contrary, 18S rRNA was at its highest at MN stage while ubtf1 in charge of activating RNA-polymerase I and synthesising 18S rRNA behaved as 5S related genes. Individuals that did not respond (NR) to the treatment showed 5S/18S index values similar to PV females, while studied genes showed EV/LV-like transcription levels. Therefore, NR females fail to express the largest rRNAs, which could thus be taken as markers of successful vitellogenesis progression. In conclusion, we have proved that the transcriptional dynamics of ribosomal genes provides useful tools to characterize induced ovarian development in European eels. In the future, such markers should be studied as putative indicators of response to hormonal treatments and of the quality of obtained eel oocytes. Copyright © 2017. Published by Elsevier Inc.

  16. A new species of Procamallanus (Nematoda: Camallanidae) from Pacific eels (Anguilla spp.)

    Czech Academy of Sciences Publication Activity Database

    Moravec, František; Justine, J.-L.; Würtz, J.; Taraschewski, H.; Sasal, P.

    2006-01-01

    Roč. 92, č. 1 (2006), s. 130-137 ISSN 0022-3395 R&D Projects: GA ČR(CZ) GA524/06/0170 Institutional research plan: CEZ:AV0Z60220518 Keywords : Procamallanus * Anguilla Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 1.300, year: 2006

  17. Swimming suppresses hepatic vitellogenesis in European female silver eels as shown by expression of the estrogen receptor 1, vitellogenin1 and vitellogenin2 in the liver

    Directory of Open Access Journals (Sweden)

    Nieveen Maaike C

    2010-03-01

    Full Text Available Abstract Background When European silver eels (Anguilla anguilla venture into the Atlantic Ocean for their 6,000 km semelparous spawning run to the Sargasso Sea, they are still in a prepubertal stage. Further sexual development appears to be blocked by dopaminergic inhibition of hypothalamus and pituitary activity. Recently, we found that swimming for several weeks in freshwater stimulated the incorporation of fat droplets in the oocytes. So, it was hypothesized that long term swimming in seawater would release the inhibition further and would also stimulate the production of vitellogenin by the liver. Methods For this study a swim-flume was constructed to allow simulated migration of migratory female silver eels for 3 months (1,420 km in natural seawater at 20 degrees C. Primers were designed for polymerase chain reactions to measure the mRNA expression of estrogen receptor 1 (esr1, vitellogenin1 (vtg1 and vitellogenin2 (vtg2 genes in the liver of European female silver eels. Results In comparison to resting eels, swimming eels showed a diminished expression of esr1, vtg1 and vtg2 in the liver. They also had lower plasma calcium (Ca; indicative of vitellogenin levels in their blood. This showed that vitellogenesis is more strongly suppressed in swimming than in resting eels. However, when eels were subsequently stimulated by 3 weekly carp pituitary extract injections, the expression of the same genes and plasma levels of Ca strongly increased in both groups to similar levels, thus equalizing the initial differences between resting and swimming. Conclusions It is concluded that vitellogenesis remains suppressed during resting and even more during swimming. The fact that swimming stimulates fat deposition in the oocytes but suppresses vitellogenesis indicates that these events are separated in nature and occur sequentially. Swimming-suppressed vitellogenesis may imply that in nature eels undergo vitellogenesis and final maturation near or at the

  18. Low PCB concentrations observed in American eel (Anguilla rostrata) in six Hudson River tributaries

    Science.gov (United States)

    Limburg, K.E.; Machut, L.S.; Jeffers, P.; Schmidt, R.E.

    2008-01-01

    We analyzed 73 eels, collected in 2004 and 2005 above the head of tide in six Hudson River tributaries, for total PCBs, length, weight, age, and nitrogen stable isotope ratios (??15N). Mean total PCB concentration (wet weight basis) was 0.23 ppm ?? 0.08 (standard error), with a range of 0.008 to 5.4 ppm. A majority of eels (84) had concentrations below 0.25 ppm, and only seven eels (10%) had concentrations exceeding 0.5 ppm. Those eels with higher PCB concentrations were ???12 yr; there was a weak correlation of PCB concentration with ??15N and also with weight. Compared to recent (2003) data from the mainstem of the Hudson River estuary, these results indicate that tributaries are generally much less contaminated with PCBs. We hypothesize that those tributary eels with high PCB concentrations were relatively recent immigrants from the mainstem. Given concern over the possible adverse effects of PCBs on eel reproduction, these tributaries may serve as refugia. Therefore, providing improved access to upland tributaries may be critically important to this species. ?? 2008 Northeastern Naturalist.

  19. Maternal transfer of emerging brominated and chlorinated flame retardants in European eels

    Energy Technology Data Exchange (ETDEWEB)

    Sühring, Roxana, E-mail: roxana.suehring@hzg.de [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Coastal Research, Department for Environmental Chemistry, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Leuphana University Lüneburg, Institute of Sustainable and Environmental Chemistry, Scharnhorststraße 1, 21335 Lüneburg (Germany); Freese, Marko [Thünen Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg (Germany); Schneider, Mandy [Leuphana University Lüneburg, Institute of Sustainable and Environmental Chemistry, Scharnhorststraße 1, 21335 Lüneburg (Germany); Schubert, Sophia; Pohlmann, Jan-Dag [Thünen Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg (Germany); Alaee, Mehran [Water Science and Technology Directorate, Environment Canada, Burlington, Ontario, L7R4A6 Canada (Canada); Wolschke, Hendrik [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Coastal Research, Department for Environmental Chemistry, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Leuphana University Lüneburg, Institute of Sustainable and Environmental Chemistry, Scharnhorststraße 1, 21335 Lüneburg (Germany); Hanel, Reinhold [Thünen Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg (Germany); Ebinghaus, Ralf [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Coastal Research, Department for Environmental Chemistry, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Marohn, Lasse [Thünen Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg (Germany)

    2015-10-15

    The European eel (Anguilla anguilla) is regarded as a critically endangered species. Scientists are in agreement that the “quality of spawners” is a vital factor for the survival of the species. This quality can be impaired by parasites, disease and pollution. Especially endocrine disrupting organic chemicals pose a potential threat to reproduction and development of offspring. To our knowledge, the findings in this publication for the first time describe maternal transfer of contaminants in eels. We analysed the concentrations of in total 53 polybrominated diphenyl ethers (PBDEs) and their halogenated substitutes in muscle, gonads and eggs of artificially matured European eels and in muscle and gonads of untreated European eels that were used for comparison. We found evidence that persistent organic pollutants such as PBDEs, as well as their brominated and chlorinated substitutes are redistributed from muscle tissue to gonads and eggs. Concentrations ranged from 0.001 ng g{sup −1} ww for sum Dechlorane metabolites (DPMA, aCL{sub 10}DP, aCl{sub 11}DP) to 2.1 ng g{sup −1} ww for TBA in eggs, 0.001 ng g{sup −1} ww for Dechlorane metabolites to 9.4 ng g{sup −1} ww for TBA in gonads and 0.002 ng g{sup −1} ww for Dechlorane metabolites to 54 ng g{sup −1} ww for TBA in muscle tissue. Average egg muscle ratios (EMRs) for compounds detectable in artificially matured eels from both Schlei Fjord and Ems River ranged from 0.01 for Dechlorane 602 (DDC-DBF) to 10.4 for PBEB. Strong correlations were found between flame retardant concentrations and lipid content in the analysed tissue types, as well as transfer rates and octanol–water partitioning coefficient, indicating that these parameters were the driving factors for the observed maternal transfer. Furthermore, indications were found, that TBP-DBPE, TBP-AE, BATE and TBA have a significant uptake from the surrounding water, rather than just food and might additionally be formed by metabolism or

  20. Structure and developmental expression of hatching enzyme genes of the Japanese eel Anguilla japonica: an aspect of the evolution of fish hatching enzyme gene.

    Science.gov (United States)

    Hiroi, Junya; Maruyama, Kouichi; Kawazu, Kouji; Kaneko, Toyoji; Ohtani-Kaneko, Ritsuko; Yasumasu, Shigeki

    2004-04-01

    We isolated seven cDNA clones from embryos of the Japanese eel Anguilla japonica. Each deduced amino acid sequence consisted of a signal peptide, a propeptide and a mature enzyme portion belonging to the astacin protease family. A phylogenetic analysis showed that the eel enzymes resembled the high choriolytic enzyme (HCE) of medaka Oryzias latipes, and the hatching enzymes of the zebra fish Danio rerio and masu salmon Oncorhynchus masou. Hatching enzymes of these teleosts belonged to the group of the medaka HCE, and not the medaka low choriolytic enzyme (LCE), another hatching enzyme of medaka. Southern blot analysis showed that the genes of the eel hatching enzymes were multicopy genes like the medaka HCE genes. However, one of the eel hatching enzyme genes comprised eight exons and seven introns, and the exon-intron organization was similar to the medaka LCE gene, which is a single-copy gene. The molecular evolution of the fish hatching enzyme genes is discussed. In addition, whole-mount in situ hybridization and immunocytochemistry showed that the eel hatching enzyme was first expressed in the pillow anterior to the forebrain of early neurula, and finally in the cell mass on the yolk sac of later stage embryos. The early differentiation profile of eel hatching gland cells was similar to that of medaka, masu salmon and zebrafish, whereas the final location of the gland cells was different among fishes. Copyright 2004 Springer-Verlag

  1. Reliability of non-lethal assessment methods of body composition and energetic status exemplified by applications to eel (Anguilla anguilla) and carp (Cyprinus carpio)

    DEFF Research Database (Denmark)

    Klefoth, Thomas; Skov, Christian; Aarestrup, Kim

    2013-01-01

    (Anguilla anguilla) and carp (Cyprinus carpio) and the dorsal white muscle of carp. Homogenizedfish flesh was used for calibration. Relative dry mass was strongly correlated with relative fat content(R2up to 96.7%) and energy density (R2up to 99.1%). Thus, calibrations were only conducted for relativedry...

  2. Changes in Plasma and Tissue Long-Chain Polyunsaturated Fatty Acid (LC-PUFA) Content in the Eel Anguilla japonica After External and Internal Osmotic Stress.

    Science.gov (United States)

    Zhang, Qinghao; Wong, Marty K S; Li, Yiqi; Li, Yuanyou; Takei, Yoshio

    2017-10-01

    We investigated the effect of external and internal osmotic stress on the profile of long-chain polyunsaturated fatty acids (LC-PUFA) in euryhaline eels Anguilla japonica. Freshwater (FW) fish were transferred to seawater (SW) for external osmotic stress or subjected to internal stress through injection with hypertonic saline. FW eels injected with isotonic saline served as controls. Plasma osmolality, Na+ concentration, and gill Na+/K+ -ATPase activity increased, but hematocrit decreased compared with controls in eels exposed to external or internal osmotic stress. The expression of two major transporter genes for SW adaptation, the Na+ -K+ -2Cl - co-transporter 1a (NKCC1a) in the gill and NKCC2b in the intestine, was up-regulated only in SW-transferred eels, suggesting a direct impact of SW on the gill and intestine via SW ingestion. Total LC-PUFA contents and DHA (22:6 n-3) increased in the gill and liver of SW-transferred eels and in the intestine of hypertonic saline-injected eels. However, total LC-PUFA content in plasma decreased after both external and internal osmotic stimuli. In contrast, the gene expression of two key enzymes involved in the LC-PUFA biosynthesis, Δ6 fatty acid desaturase and elongase, did not change in the gill, intestine and liver of osmotically stressed eels. These results indicate that LC-PUFA is possibly involved in osmoregulation and the increased LC-PUFA contents of osmoregulatory organs might be a result of LC-PUFA transport via circulation, rather than through de novo biosynthesis.

  3. Surviving in a toxic world: transcriptomics and gene expression profiling in response to environmental pollution in the critically endangered European eel

    Directory of Open Access Journals (Sweden)

    Pujolar Jose

    2012-09-01

    Full Text Available Abstract Background Genomic and transcriptomic approaches have the potential for unveiling the genome-wide response to environmental perturbations. The abundance of the catadromous European eel (Anguilla anguilla stock has been declining since the 1980s probably due to a combination of anthropogenic and climatic factors. In this paper, we explore the transcriptomic dynamics between individuals from high (river Tiber, Italy and low pollution (lake Bolsena, Italy environments, which were measured for 36 PCBs, several organochlorine pesticides and brominated flame retardants and nine metals. Results To this end, we first (i updated the European eel transcriptome using deep sequencing data with a total of 640,040 reads assembled into 44,896 contigs (Eeelbase release 2.0, and (ii developed a transcriptomic platform for global gene expression profiling in the critically endangered European eel of about 15,000 annotated contigs, which was applied to detect differentially expressed genes between polluted sites. Several detoxification genes related to metabolism of pollutants were upregulated in the highly polluted site, including genes that take part in phase I of the xenobiotic metabolism (CYP3A, phase II (glutathione-S-transferase and oxidative stress (glutathione peroxidase. In addition, key genes in the mitochondrial respiratory chain and oxidative phosphorylation were down-regulated at the Tiber site relative to the Bolsena site. Conclusions Together with the induced high expression of detoxification genes, the suggested lowered expression of genes supposedly involved in metabolism suggests that pollution may also be associated with decreased respiratory and energy production.

  4. Evaluation of methods to determine sperm density for the european eel, anguilla anguilla

    DEFF Research Database (Denmark)

    Sørensen, Sune Riis; Gallego, V.; Pérez, L.

    2013-01-01

    , computer-assisted sperm analysis (CASA) and flow cytometry (FCM), using Neubauer Improved haemocytometer as benchmark. Initially, relationships between spermatocrit, haemocytometer counts and sperm motility were analysed, as well as the effect of sperm dilution on haemocytometer counts. Furthermore...... from all techniques, spermatocrit, CASA and FCM, showed significant positive correlations with haemocytometer counts. The best correlation between spermatocrit and haemocytometer counts was obtained at 6000 × g (r = 0.68). Of two CASA variants, one or three photographic fields (CASA-1 and CASA-2), CASA...

  5. Ichthyodinium identified in the eggs of European eel (Anguilla anguilla) spawned in captivity

    DEFF Research Database (Denmark)

    Sørensen, Sune Riis; Tomkiewicz, Jonna; Skovgaard, A.

    2014-01-01

    of Ichthyodinium, a syndinian dinoflagellate parasite found in pelagic eggs of various marine fish species. Sequences of genes coding for small subunit ribosomal RNA confirmed that the organism was an Ichthyodinium species, and molecular phylogenetic analysis demonstrated the presence of two Ichthyodinium...

  6. Development of a broodstock diet to improve developmental competence of embryos in European eel, Anguilla anguilla

    DEFF Research Database (Denmark)

    Støttrup, Josianne Gatt; Tomkiewicz, Jonna; Jacobsen, Charlotte

    2016-01-01

    than in Feed 2 and DE. Female broodstock was not fed during hormonal treatment to induce vitellogenesis and ovulation. EPA levels in females fed the test diets decreased in the both muscle and ovary and were significantly lower in eggs from females fed Feed 1. The highest percentage of stripped females...

  7. Schooling reduces energy consumption in swimming male European eels, Anguilla anguilla L.

    NARCIS (Netherlands)

    Burgerhout, E.; Tudorache, C.; Brittijn, S.A.; Palstra, A.P.; Dirks, R.P.; Thillart, G.E.E.J.M.

    2013-01-01

    During migration, swimming in schools provides fish with a number of behavioural and ecological advantages, including increased food supply and reduced predation risk. Previous work shows that carangiform and tunniform swimming result in energetic advantages for individuals using a diamond swimming

  8. Assessment of testis development during induced spermatogenesis in the European eel Anguilla anguilla

    DEFF Research Database (Denmark)

    Tomkiewicz, Jonna; Kofoed, Tanja; Pedersen, Jes S.

    2011-01-01

    development stages in histological sections of the testes. The index weighs the volume fractions of the different tissues (somatic cells and germ cell stages) and describes development on a scale of 0 to 1. The method improves the existing histological classification, providing a quantitative measure...

  9. On the way to successful European eel larval rearing: Impact of biophysical conditions and gamete quality

    OpenAIRE

    Sørensen, Sune Riis; Tomkiewicz, Jonna; Munk, Peter; Bossier, P

    2014-01-01

    The European eel is a widely distributed fish species of economic and cultural importance. It inhabits both coastal and freshwater systems, and is targeted by fisheries and treasured as food item. Although eels are reared in aquaculture, this industry relies solely of wild‐caught juvenile glass eels that arrive to theEuropean coasts after a 6000 km journey from the Sargasso Sea, where they were hatched. The adolescent eels start their long migration from the European continent back to their s...

  10. A novel recombinant bivalent outer membrane protein of Vibrio vulnificus and Aeromonas hydrophila as a vaccine antigen of American eel (Anguilla rostrata).

    Science.gov (United States)

    SongLin, Guo; PanPan, Lu; JianJun, Feng; JinPing, Zhao; Peng, Lin; LiHua, Duan

    2015-04-01

    The immogenicity of a novel vaccine antigen was evaluated after immunized American eels (Anguilla rostrata) with a recombinant bivalent expressed outer membrane protein (OMP) of Vibrio vulnificus and Aeromonas hydrophila. Three groups of eels were intraperitoneal (i.p) injected with phosphate-buffered saline (PBS group), formaline-killed-whole-cell (FKC) of A. hydrophila and V. vulnificus (FKC group) or the bivalent OMP (OMP group). On 14, 21, 28 and 42 days post-vaccination respectively, proliferation of the whole blood cells, titers of specific antibody and lysozyme activities of experimental eels were detected. On 28 day post-vaccination, eels from three groups were challenged by i.p injection of live A. hydrophila or V. vulnificus. The results showed that, compared with the PBS group, proliferation of whole blood cells in OMP group was significant enhanced on 28 days, and the serum titers of anti-A.hydrophila and anti-V. vulnificus antibody in eels of FKC and OMP group were significant increased on 14, 21 and 28d. Lysozyme Activities in serum, skin mucus, liver and kidney were significant changed between the three groups. Relative Percent Survival (RPS) after challenged A. hydrophila in KFC vs. PBS group and OMP vs. PBS group were 62.5% and 50% respectively, and the RPS challenged V. vulnificus in FKC and OMP vs. PBS group were 37.5% and 50% respectively. These results suggest that American eels immunized with the bivalent OMP would positively affect specific as well as non-specific immune parameters and protect against infection by the two pathogens in fresh water farming. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Ultrasonography to assist with timing of spawning in European eel

    NARCIS (Netherlands)

    Jéhannet, Pauline; Heinsbroek, Leon T.N.; Palstra, Arjan P.

    2017-01-01

    Ovulation in the European eel can be induced by injection of DHP (17α,20β-dihydroxy-4-pregnen-3-one). The timing of injection is based on the developmental stage of the oocytes. The oocyte stage is determined by invasive biopsy or through external indicators of the oocyte hydration response: body

  12. Evaluation of head-only and head-to-tail electrical stunning of farmed eels (Anguilla anguilla, L.) for the development of a humane slaughter method

    NARCIS (Netherlands)

    Lambooij, E.; Vis, van de J.W.; Kloosterboer, R.J.; Pieterse, C.

    2002-01-01

    The overall objective was to evaluate the suitability of electronarcosis as a stunning method for farmed eels. In the first experiment the minimum electrical current needed to induce a general epileptiform insult by head-only stunning was assessed. The individual eels (n = 40) with a live weight of

  13. The effect of para-nonylphenol on Japanese eel (Anguilla japonica) spermatogenesis in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Miura, C. [Laboratory of Fish Reproductive Physiology, Faculty of Agriculture, Ehime University, Matsuyama, Ehime 790-8566 (Japan); ' Times Arrow and Biosignaling' PRESTO Japan Science and Technology Agency, Kawaguchi 332-0012 (Japan); Takahashi, N. [Iwate Fisheries Technology Center, Fisheries and Resource Management Division, 3-75-3 Oaza-hirata, Kamaishi, Iwate 026-0001 (Japan); Michino, F. [Laboratory of Fish Reproductive Physiology, Faculty of Agriculture, Ehime University, Matsuyama, Ehime 790-8566 (Japan); Miura, T. [Laboratory of Fish Reproductive Physiology, Faculty of Agriculture, Ehime University, Matsuyama, Ehime 790-8566 (Japan); ' Times Arrow and Biosignaling' PRESTO Japan Science and Technology Agency, Kawaguchi 332-0012 (Japan)

    2005-01-26

    Endocrine disrupters have been recognized to interfere with endocrine systems that regulate reproduction, for example, by mimicking or inhibiting the action of endogenous sex steroid hormones including estradiol-17{beta} (E2). In the present study, we examined the effect of an endocrine disrupter, para-nonylphenol (p-NP) on spermatogenesis, and compared it with the action of E2, using an eel testicular organ culture system. p-NP alone stimulated early spermatogonial renewal in the same manner as E2. Neither induced further progress in spermatogenesis. In the presence of 11-ketotestosterone (11-KT), the major androgen in teleosts, p-NP did not prevent the 11-KT-induced progress in spermatogenesis. However, this treatment enlarged the Sertoli cells. Electron microscopic observation revealed that enlarged Sertoli cells contained well-developed organelles. Moreover, the proportion of germ cells appeared to have decreased as a result of Sertoli cell hypertrophy. These results clearly show that p-NP has an effect on Sertoli cells in the presence of an androgen (11-KT), potentially disturbing 11-KT-induced spermatogenesis.

  14. A review on broodstock nutrition of marine pelagic spawners: the curious case of the freshwater eels (Anguilla spp.)

    DEFF Research Database (Denmark)

    Heinsbroek, L.T.N.; Støttrup, J.G.; Jacobsen, C.

    2013-01-01

    in the eggs of farmed eels were not detrimental. The total free amino acid amount and profile of eel eggs appears much different from other marine pelagic spawners. Nutritional intervention to influence egg composition seems feasible, but responsiveness of farmed eels to induced maturation might also require...... marine pelagic spawners. Freshwater eels spawn marine pelagic eggs with an oil droplet (type II), and with a large perivitelline space. Compared with other marine fish eggs, eel eggs are at the extreme end of the spectrum in terms of egg composition, even within this type II group. Eel eggs contain...... a large amount of total lipids, and a shortage of neutral lipids has been implied a cause for reduced survival of larvae. Eel eggs have higher ARA but lower EPA and DHA levels than in other fish. Too high levels of ARA negatively affected reproduction in the Japanese eel, although high levels of 18:2n‐6...

  15. A review on broodstock nutrition of marine pelagic spawners: the curious case of the freshwater eels (Anguilla spp.)

    NARCIS (Netherlands)

    Heinsbroek, L.T.N.; Støttrup, J.G.; Jacobsen, C.; Corraze, G.; Kraiem, M.M.; Holst, L.K.; Tomkiewicz, J.; Kaushik, S.J.

    2013-01-01

    To sustain eel aquaculture, development of reproduction in captivity is vital. The aim of this review is to assess our current knowledge on the nutrition of broodstock eels in order to improve the quality of broodstock under farming conditions, drawing information from wild adult eels and other

  16. Growth and seasonal behavior of Anguilla anguilla in the River Minho tidal freshwater wetlands

    Directory of Open Access Journals (Sweden)

    Helena Correia

    2015-11-01

    Full Text Available The River Minho estuary, located on the northwest coast of the Iberian Peninsula, is a mesotidal estuary, partially mixed that during the period of high floods it tends to evolve towards a salt wedge estuary. The influence of spring tides extends approximately 40 km upstream and the tidal freshwater wetlands (TFWs are located in the upper 30 km. The Minho estuary is part of a Natura 2000 site, which includes the entire international section of the river being considered a very important river concerning migratory fish species. In the River Minho TFWs several fish species have ecological and economic value (Salmo trutta, Alosa fallax, Platichthys flesus, Anguilla anguilla, Salmo salar, Alosa alosa and Petromyzon marinus. European eel, A. anguilla, is in Appendix II of CITES list, that includes species not necessarily threatened with extinction, but in which trade must be controlled in order to avoid utilization incompatible with their survival. Between January 2007 and December 2014, in a selected semi-enclosed area of TFW and using 5 fyke-nets, were captured 1303 eels. All eels were measured and weighted, ocular index was determined and also marked with pit-tags and released in the same area. During these 8 years of work, around 15% of the total captured eels were recaptured once, less than 3% were recapture twice, less than 1% three times and 3 eels were recaptured 4 times. Eels marked in 2009 are until now the ones that were recaptured more times. Biological data as eel growth, seaward migration state, seasonal differences of by-catch will be crossed with abiotic data namely river flow, precipitation and water temperature.

  17. The disappearance of the European eel from the western Wadden Sea

    NARCIS (Netherlands)

    van der Meer, J.; van der Veer, H.W.; Witte, J.IJ.

    2011-01-01

    A cohort model for the European eel is presented, which enables the interpretation of observed catches of yellow eel and silver eel in the western Wadden Sea in terms of recruitment data of glasseel. The model builds on various assumptions on length-dependent mortality and silvering rates and on the

  18. Rhabdochona (Rhabdochona) keralaensis sp nov (Rhabdochonidae) and some other nematodes in the Indian mottled eel Anguilla bengalensis bengalensis from India

    Czech Academy of Sciences Publication Activity Database

    Moravec, František; Sheeba, S.; Kumar, A. B.

    2012-01-01

    Roč. 57, č. 1 (2012), 74-82 ISSN 1230-2821 R&D Projects: GA MŠk LC522 Institutional research plan: CEZ:AV0Z60220518 Keywords : Rhabdochona * Anguilla * India Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 1.000, year: 2012

  19. Qualitative assessment of the diet of European eel larvae in the Sargasso Sea resolved by DNA barcoding

    DEFF Research Database (Denmark)

    Riemann, L.; Alfredsson, H.; Hansen, Michael Møller

    2010-01-01

    that even the smallest larvae feed on a striking variety of plankton organisms, and that gelatinous zooplankton is of fundamental dietary importance. Hence, the specific plankton composition seems essential for eel larval feeding and growth, suggesting a linkage between eel survival and regional plankton......, the Sargasso Sea is oligotrophic, with generally low plankton biomass, and the feeding biology of eel larvae has so far remained a mystery, hampering understanding of this peculiar life history. DNA barcoding of gut contents of 61 genetically identified A. anguilla larvae caught in the Sargasso Sea showed...

  20. Sensitivity of advective transfer times across the North Atlantic Ocean to the temporal and spatial resolution of model velocity data: Implication for European eel larval transport

    Science.gov (United States)

    Blanke, Bruno; Bonhommeau, Sylvain; Grima, Nicolas; Drillet, Yann

    2012-05-01

    European eel (Anguilla anguilla) larvae achieve one of the longest larval migrations of the marine realm, i.e., more than 6000 km from their spawning grounds in the Sargasso Sea to European continental shelves. The duration of this migration remains debated, between 7 months and 3 years. This information is, however, crucial since it determines the period over which larvae are affected by environmental conditions and hence the subsequent recruitment success. We investigate the pathways and duration of trans-Atlantic connections using 3 years of high-resolution (daily, 1/12°) velocity fields available from a Mercator-Océan model configuration without data assimilation. We study specifically the effect of spatial and temporal resolutions on our estimates by applying various filters in time (from daily to 12-day averages) and space (from 1/12° to 1° gridcell aggregation) to the nominal model outputs. Numerical particles are released in the presumed European eel spawning area and considered as passive tracers at three specific depths (around 0, 50, and 200 m). We diagnose particularly the intensity of the water transfer between suitable control sections that encompass the eel larva distribution. Transit ages are also investigated, with a particular focus on the pathways that minimize the connection times between the western and eastern North Atlantic. We show that small-scale structures (eddies and filaments) contribute to faster connections though they also correspond to additional complexity in trajectories. The shortest pathways mostly follow the Gulf Stream and the North Atlantic Drift, whereas interior connections require longer transfers that prove less compatible with biological observations.

  1. Temporal progression in migratory status and sexual maturation in European silver eels during downstream migration

    NARCIS (Netherlands)

    Palstra, A.P.; Guerrero, M.A.; Klein Breteler, J.G.P.; Thillart, G.E.E.J.M.

    2011-01-01

    The onset of downstream migration of European eels is accompanied by a cessation of feeding and the start of sexual maturation which stresses the link between metabolism and sexual maturation, also suggesting an important role for exercise. Exercise has been tested with eels in swim tunnels and was

  2. On the way to successful European eel larval rearing: Impact of biophysical conditions and gamete quality

    DEFF Research Database (Denmark)

    Sørensen, Sune Riis

    The European eel is a widely distributed fish species of economic and cultural importance. It inhabits both coastal and freshwater systems, and is targeted by fisheries and treasured as food item. Although eels are reared in aquaculture, this industry relies solely of wild‐caught juvenile glass...

  3. Development and testing of attachment methods for pop-up satellite archival transmitters in European eel

    DEFF Research Database (Denmark)

    Økland, Finn; Thorstad, Eva B.; Westerberg, Håkan

    2013-01-01

    Background Four methods for attaching pop-up satellite transmitters to European eel were tested in the laboratory by recording long-term tag retention, growth and survival; short-term behavioral responses; and physical damage from attachments. Results All eels survived until they lost their tag...

  4. European eel sperm diluent for short-term storage.

    Science.gov (United States)

    Peñaranda, D S; Pérez, L; Gallego, V; Barrera, R; Jover, M; Asturiano, J F

    2010-06-01

    The sperm of European eel shows a high density and the time of spermatozoa motility is very short after activation with sea water. These characteristics make difficult the sperm handling and its quality assessment. Several diluents were previously described for the Japanese eel obtaining over 3 weeks' conservation times under refrigeration, but they rendered bad results in the European species. In the present study, several diluents were developed taking as basis the P1 medium, and using different dilution ratios (1 : 50, 1 : 100) and two pH (6.5, 8.5). The effect of the addition of bovine serum albumin (BSA, 2% w/v) was also evaluated. At 24 h, undiluted samples already showed significant lower motility and viability than sperm samples diluted in the different media. The results for diluents with pH 6.5 and 8.5 were different. Spermatozoa diluted in media at pH 6.5 cannot be activated at 24 h, while samples diluted in the diluents with pH 8.5 and added with BSA did not show significant differences with respect to the fresh sperm motility until 48 h. The viability (percentage of alive cells) did not show differences until 1 week, independent of the dilution ratio. After 1 week, the motility was approximately 30% in the media containing BSA, which presented no differences for head size of the spermatozoa (perimeter and area) until 72 h and 1 week, respectively. In conclusion, the combination of one medium having similar physico-chemical characteristics to the seminal plasma, including pH 8.5, and supplemented with BSA can be used in different dilution ratios for the sperm's short-term storage, preserving its motility capacity.

  5. Tools and triggers for eel reproduction

    NARCIS (Netherlands)

    Burgerhout, Erik

    2013-01-01

    Freshwater eels (Anguilla spp.) intrigued scientists for centuries. Their life cycle involves for example two distinct larval stages and a long distance migration, which may cover thousands of kilometers. The farming of eels is still dependent on the influx of wild glass eels, because eels do not

  6. [Demonstration of leucine aminopeptidase in the peritoneal epithelium of early post-larval stages of Anguilla anguilla L.)].

    Science.gov (United States)

    Bremer, H

    1975-01-01

    The coelom of elvers (Anguilla anguilla L.), eel0, is contenting glycoproteids, but these are not improvable in following stages of development. In peritoneal epithelium of eel0 activity of leucinamino-peptidase is present, but absent in the stage 2a. We can suppose that glycoproteids vanish by enzymatic catabolism and resorption within the peritoneal epithelium.

  7. A ddRAD-based genetic map and its integration with the genome assembly of Japanese eel (Anguilla japonica) provides insights into genome evolution after the teleost-specific genome duplication.

    Science.gov (United States)

    Kai, Wataru; Nomura, Kazuharu; Fujiwara, Atushi; Nakamura, Yoji; Yasuike, Motoshige; Ojima, Nobuhiko; Masaoka, Tetsuji; Ozaki, Akiyuki; Kazeto, Yukinori; Gen, Koichiro; Nagao, Jiro; Tanaka, Hideki; Kobayashi, Takanori; Ototake, Mitsuru

    2014-03-26

    Recent advancements in next-generation sequencing technology have enabled cost-effective sequencing of whole or partial genomes, permitting the discovery and characterization of molecular polymorphisms. Double-digest restriction-site associated DNA sequencing (ddRAD-seq) is a powerful and inexpensive approach to developing numerous single nucleotide polymorphism (SNP) markers and constructing a high-density genetic map. To enrich genomic resources for Japanese eel (Anguilla japonica), we constructed a ddRAD-based genetic map using an Ion Torrent Personal Genome Machine and anchored scaffolds of the current genome assembly to 19 linkage groups of the Japanese eel. Furthermore, we compared the Japanese eel genome with genomes of model fishes to infer the history of genome evolution after the teleost-specific genome duplication. We generated the ddRAD-based linkage map of the Japanese eel, where the maps for female and male spanned 1748.8 cM and 1294.5 cM, respectively, and were arranged into 19 linkage groups. A total of 2,672 SNP markers and 115 Simple Sequence Repeat markers provide anchor points to 1,252 scaffolds covering 151 Mb (13%) of the current genome assembly of the Japanese eel. Comparisons among the Japanese eel, medaka, zebrafish and spotted gar genomes showed highly conserved synteny among teleosts and revealed part of the eight major chromosomal rearrangement events that occurred soon after the teleost-specific genome duplication. The ddRAD-seq approach combined with the Ion Torrent Personal Genome Machine sequencing allowed us to conduct efficient and flexible SNP genotyping. The integration of the genetic map and the assembled sequence provides a valuable resource for fine mapping and positional cloning of quantitative trait loci associated with economically important traits and for investigating comparative genomics of the Japanese eel.

  8. Signatures of natural selection between life cycle stages separated by metamorphosis in European eel

    DEFF Research Database (Denmark)

    Pujolar, J.M.; Jacobsen, M.W.; Bekkevold, Dorte

    2015-01-01

    supports the adaptive decoupling hypothesis for the benefits of metamorphosis. Partitioning the life cycle into discrete morphological phases may be overall beneficial since it allows the different life stages to respond independently to their unique selection pressures. This might translate into a more......Species showing complex life cycles provide excellent opportunities to study the genetic associations between life cycle stages, as selective pressures may differ before and after metamorphosis. The European eel presents a complex life cycle with two metamorphoses, a first metamorphosis from larvae...... into glass eels (juvenile stage) and a second metamorphosis into silver eels (adult stage). We tested the hypothesis that different genes and gene pathways will be under selection at different life stages when comparing the genetic associations between glass eels and silver eels. Results: We used two sets...

  9. The Use of Water Exchange for Feeding Rate and Growth Promotion of Shortfin Eel Anguilla bicolor bicolor In Recirculating Water System

    Science.gov (United States)

    Taufiq-Spj, N.; Sunaryo, S.; Wirasatriya, A.; Sugianto, D. N.

    2017-02-01

    The shortage of eel’s seed Anguilla spp. and it’s consumption size will induce the hunting of this species. Thus, stocks are critically endangered. Central Java have two indigenious species i.e. A. marmorata and A. bicolor bicolor. These two species will be endanger if management of stock do not conduct properly. The use of water exchange by replacing water volume for feeding rate and growth promotion of Indonesian shortfin eel A. bicolor bicolor in RWS will at least give a basic information in appropriate aquaculture systems and as a part of disaster mitigation of indegenious species extinction. The study used 3 replications and 3 treatments of water exchange, i.e. T1: 50, T2: 100, and T3: 200 % of water removed d-1. The fish were fed with approx. 2.2% dry basis of formulated feed. Tanks with volume of 1 m3 contain a density of approx. 20 kg seed stock of shortfin eel fingerlink size per m3 water in RSW. The result shows that feeding rate among treatments are significantly different (α < 0.001), where T1= 1.62±0.23% d-1, T2 = 1.89±0.06% d-1 and T3 = 1.99±0.06% d-1. Individual and Biomass weight gain increase (IWG: T1= 0.039±0.003, T2= 0.050±0.001, T3= 0.076±0.002 kg and BWG: T1= 7.087±0.443, T2 = 11.051±0.894, T3= 19.722±0.831 kg respectively) by increasing water exchange (α < 0.001). Meanwhile the absolute growth was found higher in individual (IAG) compare to biomass (BAG) and both of them increase by increasing water exchange (α < 0.001). Where for IAG: T1= 55.42±3.69, T2= 71.02±2.40, T3= 106.12±1.98% and BAG: T1= 35.11±1.13, T2= 52.94±6.17, T3= 90.77±3.14% respectively.

  10. Movement patterns of seaward migrating European eel (Anguilla anguilla) at a complex of riverine barriers: implications for conservation

    DEFF Research Database (Denmark)

    Piper, Adam T.; Svendsen, Jon Christian; Wright, Rosalind M.

    2017-01-01

    River infrastructure such as weirs and hydropower stations commonly present migrating fish with multiple potential passage routes. Knowledge of the cues fish use to navigate such environments is required to protect migrants from hazardous areas and guide them towards safe passage; however...

  11. Empirical observations of the spawning migration of European eels: The long and dangerous road to the Sargasso Sea

    DEFF Research Database (Denmark)

    Righton, David; Westerberg, H.; Feunteun, E.

    2016-01-01

    Fresh data on the timing and speed of the oceanic spawning migration of European eels suggest a new paradigm for spawning ecology.......Fresh data on the timing and speed of the oceanic spawning migration of European eels suggest a new paradigm for spawning ecology....

  12. Female nutrition and assisted reproduction in European eel: influences on oogenesis and egg quality

    DEFF Research Database (Denmark)

    da Silva, Filipa

    maturation scale, which may result in an increase in production of viable European eel eggs. Overall, this PhD project contributed to the development of assisted reproduction procedures by providing new and valuable knowledge about the factors influencing the maturational response of European female eels...... in techniques for induction of maturation and fertilization of the eggs has enabled the production of many viable eggs and yolk-sac larvae that are able of exogenous feeding. The present studies have contributed to this progress by addressing some of the challenges commonly associated with the induction...

  13. Evolution of the Freshwater Eels

    Science.gov (United States)

    Aoyama, Jun; Tsukamoto, Katsumi

    The freshwater anguillid eels have an unusual life history and world-wide distribution. Questions about the phylogenetic relationships of this group and how their long spawning migrations and larval phase may contribute to their global distribution have not been addressed. This paper is first presentation of molecular phylogeny of Anguilla species, and based on this phylogenetic tree we suggest new aspect of the evolution of this group. Namely, ancestral eels originated during the Eocene or earlier, in the western Pacific Ocean near present-day Indonesia. A group derived from this ancestor dispersed westward, probably by larval transport in the global circum-equatorial current through the northern edge of the Tethys Sea. This group split into the ancestor of the European and American eels, which entered into the Atlantic Ocean, and a second group, which dispersed southward and split into the east African species and Australian species. Thus the world-wide distribution of the eel family can be understood from knowledge of continental drift, ocean currents, a specialized larva and evolutionary forces favoring dispersal and speciation of segregated gene pool.

  14. First-feeding by European eel larvae: A step towards closing the life cycle in captivity

    DEFF Research Database (Denmark)

    Butts, Ian; Sørensen, Sune Riis; Politis, Sebastian Nikitas

    2016-01-01

    First evidence of first-feeding European eel larvae that have been reared in captivity•Up to 50% of larvae ingested a diet composed of concentrated rotifer paste, with or without natural feeding stimulants•Documentation of a significant increase in feeding success under higher light intensities•R...

  15. Eel population dynamic and habitat relationships in the European southern tip.

    Directory of Open Access Journals (Sweden)

    Ramon José De Miguel

    2015-11-01

    According to our previous results, the eel population in the most southern region in Europe shows similar averages in dynamic population indicators compared to other European areas. On the other hand, no environmental predictors showed major influence on catchability, except for, those related to previous abundant rainfalls.

  16. The Pituitary Gland of the European Eel Reveals Massive Expression of Genes Involved in the Melanocortin System

    Science.gov (United States)

    Ager-Wick, Eirill; Dirks, Ron P.; Burgerhout, Erik; Nourizadeh-Lillabadi, Rasoul; de Wijze, Daniëlle L.; Spaink, Herman P.; van den Thillart, Guido E. E. J. M.; Tsukamoto, Katsumi; Dufour, Sylvie; Weltzien, Finn-Arne; Henkel, Christiaan V.

    2013-01-01

    Hormones secreted from the pituitary gland regulate important processes such as development, growth and metabolism, reproduction, water balance, and body pigmentation. Synthesis and secretion of pituitary hormones are regulated by different factors from the hypothalamus, but also through feedback mechanisms from peripheral organs, and from the pituitary itself. In the European eel extensive attention has been directed towards understanding the different components of the brain-pituitary-gonad axis, but little is known about the regulation of upstream processes in the pituitary gland. In order to gain a broader mechanistic understanding of the eel pituitary gland, we have performed RNA-seq transcriptome profiling of the pituitary of prepubertal female silver eels. RNA-seq reads generated on the Illumina platform were mapped to the recently assembled European eel genome. The most abundant transcript in the eel pituitary codes for pro-opiomelanocortin, the precursor for hormones of the melanocortin system. Several genes putatively involved in downstream processing of pro-opiomelanocortin were manually annotated, and were found to be highly expressed, both by RNA-seq and by qPCR. The melanocortin system, which affects skin color, energy homeostasis and in other teleosts interacts with the reproductive system, has so far received limited attention in eels. However, since up to one third of the silver eel pituitary’s mRNA pool encodes pro-opiomelanocortin, our results indicate that control of the melanocortin system is a major function of the eel pituitary. PMID:24130881

  17. The pituitary gland of the European eel reveals massive expression of genes involved in the melanocortin system.

    Directory of Open Access Journals (Sweden)

    Eirill Ager-Wick

    Full Text Available Hormones secreted from the pituitary gland regulate important processes such as development, growth and metabolism, reproduction, water balance, and body pigmentation. Synthesis and secretion of pituitary hormones are regulated by different factors from the hypothalamus, but also through feedback mechanisms from peripheral organs, and from the pituitary itself. In the European eel extensive attention has been directed towards understanding the different components of the brain-pituitary-gonad axis, but little is known about the regulation of upstream processes in the pituitary gland. In order to gain a broader mechanistic understanding of the eel pituitary gland, we have performed RNA-seq transcriptome profiling of the pituitary of prepubertal female silver eels. RNA-seq reads generated on the Illumina platform were mapped to the recently assembled European eel genome. The most abundant transcript in the eel pituitary codes for pro-opiomelanocortin, the precursor for hormones of the melanocortin system. Several genes putatively involved in downstream processing of pro-opiomelanocortin were manually annotated, and were found to be highly expressed, both by RNA-seq and by qPCR. The melanocortin system, which affects skin color, energy homeostasis and in other teleosts interacts with the reproductive system, has so far received limited attention in eels. However, since up to one third of the silver eel pituitary's mRNA pool encodes pro-opiomelanocortin, our results indicate that control of the melanocortin system is a major function of the eel pituitary.

  18. Eel Kisspeptins: Identification, Functional Activity, and Inhibition on both Pituitary LH and GnRH Receptor Expression

    Directory of Open Access Journals (Sweden)

    Jérémy Pasquier

    2018-01-01

    Full Text Available The European eel (Anguilla anguilla presents a blockade of sexual maturation at a prepubertal stage due to a deficient production of gonadotropins. We previously initiated, in the eel, the investigation of the kisspeptin system, one of the major gatekeepers of puberty in mammals, and we predicted the sequence of two Kiss genes. In the present study, we cloned and sequenced Kiss1 and Kiss2 cDNAs from the eel brain. The tissue distributions of Kiss1 and Kiss2 transcripts, as investigated by quantitative real-time PCR, showed that both genes are primarily expressed in the eel brain and pituitary. The two 10-residue long sequences characteristic of kisspeptin, eel Kp1(10 and Kp2(10, as well as two longer sequences, predicted as mature peptides, eel Kp1(15 and Kp2(12, were synthesized and functionally analyzed. Using rat Kiss1 receptor-transfected Chinese hamster ovary cells, we found that the four synthesized eel peptides were able to induce [Ca2+]i responses, indicating their ability to bind mammalian KissR-1 and to activate second messenger pathways. In primary culture of eel pituitary cells, all four peptides were able to specifically and dose-dependently inhibit lhβ expression, without any effect on fshβ, confirming our previous data with heterologous kisspeptins. Furthermore, in this eel in vitro system, all four peptides inhibited the expression of the type 2 GnRH receptor (gnrh-r2. Our data revealed a dual inhibitory effect of homologous kisspeptins on both pituitary lhβ and gnrh-r2 expression in the European eel.

  19. Thirty year monitoring of PCBs, organochlorine pesticides and tetrabromodiphenylether in eel from The Netherlands

    Energy Technology Data Exchange (ETDEWEB)

    Boer, Jacob de, E-mail: jacob.de.boer@ivm.vu.n [VU University, Institute for Environmental Studies, De Boelelaan 1087, 1081 HV Amsterdam (Netherlands); Dao, Quy T., E-mail: quy.dao@wur.n [Wageningen IMARES: Institute for Marine Resources and Ecosystem Studies, P.O. Box 68, 1970 AB IJmuiden (Netherlands); Leeuwen, Stefan P.J. van, E-mail: stefan.van.leeuwen@ivm.vu.n [VU University, Institute for Environmental Studies, De Boelelaan 1087, 1081 HV Amsterdam (Netherlands); Kotterman, Michiel J.J., E-mail: michiel.kotterman@wur.n [Wageningen IMARES: Institute for Marine Resources and Ecosystem Studies, P.O. Box 68, 1970 AB IJmuiden (Netherlands); Schobben, John H.M., E-mail: john.schobben@wur.n [Wageningen IMARES: Institute for Marine Resources and Ecosystem Studies, P.O. Box 68, 1970 AB IJmuiden (Netherlands)

    2010-05-15

    Because of their excellent properties as a biomonitor, yellow eels (Anguilla anguilla) have been used for time-trend monitoring of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and tetrabrominated diphenylether (tetra-BDE). The program has now lasted for thirty years and has delivered valuable information on trends and spatial differences of these compounds in the delta of the rivers Rhine and Meuse and other Dutch canals, rivers and lakes. Specific local PCB, HCH and dieldrin contaminations were identified. Temporal trends show a slow decrease of PCB concentrations since 1977. Eels from the rivers Rhine and Meuse still exceed present European maximum residue limits for dioxin-like PCBs. Apart from some exceptions, OCP and tetra-BDE concentrations have also decreased, and more than those of PCBs. Fat contents of eel have decreased from an average of 21 to ca. 13%. This decrease in fat contents, coincides with the strong reduction of the European eel stock. - Results of thirty-year eel monitoring in The Netherlands reveal decreasing PCB and organochlorine pesticide concentrations, and the identification of specific local contaminations.

  20. An evaluation of indices of gross pathology associated with the nematode Anguillicoloides crassus in eels

    NARCIS (Netherlands)

    Lefebvre, F.; Fazio, G.; Palstra, A.P.; Szekely, C.; Crivelli, A.J.

    2011-01-01

    This study compares two alternative indices for quantifying the gross pathology of the swimbladder of eels, Anguilla anguilla (L.), infected with the nematode Anguillicoloides crassus. Two observers recorded twice the scores obtained by the two indices on the same set of 71 wild caught eels (from

  1. An otolith microchemistry study of possible relationships between the origins of leptocephali of European eels in the Sargasso Sea and the continental destinations and relative migration success of glass eels

    DEFF Research Database (Denmark)

    Martin, J.; Daverat, F.; Pécheyran, C.

    2010-01-01

    Little is known about the extent to which Atlantic eels coming from different European rivers converge on the same spawning site. Our aim was to evaluate the spatial homogeneity of eel spawning area(s) with an otolith microchemistry approach. This work compared the elemental signatures of otolith...

  2. Thirty year monitoring of PCBs, organochlorine pesticides and tetrabromodiphenylether in eel from The Netherlands.

    Science.gov (United States)

    de Boer, Jacob; Dao, Quy T; van Leeuwen, Stefan P J; Kotterman, Michiel J J; Schobben, John H M

    2010-05-01

    Because of their excellent properties as a biomonitor, yellow eels (Anguilla anguilla) have been used for time-trend monitoring of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and tetrabrominated diphenylether (tetra-BDE). The program has now lasted for thirty years and has delivered valuable information on trends and spatial differences of these compounds in the delta of the rivers Rhine and Meuse and other Dutch canals, rivers and lakes. Specific local PCB, HCH and dieldrin contaminations were identified. Temporal trends show a slow decrease of PCB concentrations since 1977. Eels from the rivers Rhine and Meuse still exceed present European maximum residue limits for dioxin-like PCBs. Apart from some exceptions, OCP and tetra-BDE concentrations have also decreased, and more than those of PCBs. Fat contents of eel have decreased from an average of 21 to ca. 13%. This decrease in fat contents, coincides with the strong reduction of the European eel stock. Copyright 2010 Elsevier Ltd. All rights reserved.

  3. Sympatric spawning but allopatric distribution of Anguilla japonica and Anguilla marmorata: temperature- and oceanic current-dependent sieving.

    Directory of Open Access Journals (Sweden)

    Yu-San Han

    Full Text Available Anguilla japonica and Anguilla marmorata share overlapping spawning sites, similar drifting routes, and comparable larval durations. However, they exhibit allopatric geographical distributions in East Asia. To clarify this ecological discrepancy, glass eels from estuaries in Taiwan, the Philippines, Indonesia, and China were collected monthly, and the survival rate of A. marmorata under varying water salinities and temperatures was examined. The composition ratio of these 2 eel species showed a significant latitude cline, matching the 24 °C sea surface temperature isotherm in winter. Both species had opposing temperature preferences for recruitment. A. marmorata prefer high water temperatures and die at low water temperatures. In contrast, A. japonica can endure low water temperatures, but their recruitment is inhibited by high water temperatures. Thus, A. japonica glass eels, which mainly spawn in summer, are preferably recruited to Taiwan, China, Korea, and Japan by the Kuroshio and its branch waters in winter. Meanwhile, A. marmorata glass eels, which spawn throughout the year, are mostly screened out in East Asia in areas with low-temperature coastal waters in winter. During summer, the strong northward currents from the South China Sea and Changjiang River discharge markedly block the Kuroshio invasion and thus restrict the approach of A. marmorata glass eels to the coasts of China and Korea. The differences in the preferences of the recruitment temperature for glass eels combined with the availability of oceanic currents shape the real geographic distribution of Anguilla japonica and Anguilla marmorata, making them "temperate" and "tropical" eels, respectively.

  4. Anguilla mossambica Peters, 1852

    African Journals Online (AJOL)

    Table 4 A comparison of growth rates in mm of various Anguilla populations. Species, locality and authority. A. anguilla, Windermere (UK) (Frost 1945). A. angUilla, N. Germany (Frost 1945). A. angUilla, Italy (Frost 1945). A. anguilla, France (Frost 1945). A. japonica, Japan (Tesch 1977). A. diffenbachi, New Zealand (Tesch ...

  5. Review of the Freshwater Eels of Iran (Family Anguillidae)

    OpenAIRE

    Brian W. Coad

    2016-01-01

    The systematics, morphology, distribution, biology, economic importance and conservation of the freshwater eel (Anguilla anguilla) of Iran are described, the species is illustrated, and a bibliography on this fish in Iran is provided. The species is found in the Caspian Sea basin as an exotic.

  6. Impact of a short-term exposure to tributyl phosphate on morphology, physiology and migratory behaviour of European eels during the transition from freshwater to the marine environment

    DEFF Research Database (Denmark)

    Privitera, Lucia; Aarestrup, Kim; Moore, Andy

    2013-01-01

    Migrating silver European eels were exposed for 5 days in a laboratory to an environmental level of tributyl phosphate (TBP), tagged with acoustic transmitters and released below the Tange hydropower station, on the River Gudenaa, Denmark. The subsequent movements of the eels were monitored...... in freshwater and 3 days after transfer to saltwater. However, there were no mortalities when the eels were transferred to full strength sea water. Exposure to TBP did not appear to have a significant effect on the subsequent movements of the eels in the river or fjord. The eels moved rapidly through the fjord...... predominantly at night. The results of the study are discussed in relation to the impact of diffuse pollution on the behaviour and physiology of European eels...

  7. First evidence of European eels exiting the Mediterranean Sea during their spawning migration

    DEFF Research Database (Denmark)

    Amilhat, Elsa; Aarestrup, Kim; Faliex, Elisabeth

    2016-01-01

    female silver eels from the south of France with pop-up satellite tags during escapement from coastal waters. Once in deeper water, the eels quickly established diel vertical migration (DVM) between the upper and lower mesopelagic zone. Five tagged eels were taken by predators within the Mediterranean...

  8. Timing and pattern of annual silver eel migration in two European watersheds are determined by similar cues.

    Science.gov (United States)

    Sandlund, Odd Terje; Diserud, Ola H; Poole, Russell; Bergesen, Knut; Dillane, Mary; Rogan, Gerard; Durif, Caroline; Thorstad, Eva B; Vøllestad, Leif Asbjørn

    2017-08-01

    Many animals perform long-distance migrations in order to maximize lifetime reproductive success. The European eel migrates several thousand kilometers between their feeding habitats in continental waters (fresh-, brackish, and sea water) and their spawning area in the Sargasso Sea. Eels residing in freshwaters usually initiate their spawning migration as silver eels during autumn, triggered by diverse environmental cues. We analyzed the time series of silver eel downstream migration in Burrishoole, Ireland (1971-2015), and Imsa, Norway (1975-2015), to examine factors regulating the silver eel migration from freshwater to the sea. The migration season (90% of the run) generally lasted from 1 August to 30 November. Environmental factors acting in the months before migration impacted timing and duration of migration, likely through influencing the internal processes preparing the fish for migration. Once the migration had started, environmental factors impacted the day-to-day variation in number of migrants, apparently stimulating migration among those eels ready for migration. Both the day-to-day variation in the number of migrants and the onset of migration were described by nearly identical models in the two rivers. Variables explaining day-to-day variation were all associated with conditions that may minimize predation risk; number of migrants was reduced under a strong moon and short nights and increased during high and increasing water levels. Presence of other migrants stimulated migration, which further indicates that silver eel migration has evolved to minimize predation risk. The onset of migration was explained mainly by water levels in August. The models for duration of the migration season were less similar between the sites. Thus, the overall migration season seems governed by the need to reach the spawning areas in a synchronized manner, while during the actual seaward migration, antipredator behavior seems of overriding importance.

  9. Is the Atlantic surface temperature a good proxy for forecasting the recruitment of European eel in the Guadalquivir estuary?

    Science.gov (United States)

    Gutiérrez-Estrada, Juan Carlos; Pulido-Calvo, Inmaculada

    2015-01-01

    This study analysed the possibility of using the sea surface temperature (SST) of the Atlantic Ocean to predict the recruitment of European eels in one of the most important estuaries of the south of Europe. For this purpose, two different time series concerning glass eel in the Guadalquivir estuary (the first obtained from a set of fishery-independent experimental samplings in this estuary and the second from an unofficial database on commercial catches provided by one of the main local marketer-buyers) were standardised to obtain a single time series on a monthly scale. This series was correlated with a total of 368 SST time series for 368 sectors of 1.95° × 1.95° of the Atlantic Ocean covering the possible migration routes of adult eels and leptocephalous larvae. The significant sectors were clustered and selected as inputs for artificial neural network models (ANNs) with the objective of obtaining a model to forecast glass eel recruitment. Globally, the best result was given by an ANN with only 12 clusters as input variables and 35 neurons in the hidden layer. For this configuration, the explained variance in the test phase was slightly higher than 79%. These results were significantly better than those obtained with classical methods. The strong correlation between predicted and observed glass eel abundance suggests that: (a) there is a marked non-linear relationship between SST and glass eel recruitment in the Guadalquivir estuary; (b) SST is a good proxy for predicting glass eel recruitment and; (c) one of the main factors responsible for the changes in abundance of this species is changes in the ocean conditions.

  10. The effect of nearly closed RAS on the feed intake and growth of Nile tilapia (Oreochromis niloticus), African catfish (Clarias gariepinus) and European eel (Anguilla anguilla)

    NARCIS (Netherlands)

    Mota, V.C.; Limbu, P.; Martins, C.I.; Eding, E.H.; Verreth, J.A.J.

    2015-01-01

    One of the challenges that Recirculating Aquaculture Systems (RAS) are still facing is the risk that in RAS fish grow less than in flow-through systems due to the accumulation of substances originating from feed, fish or bacteria associated with the water re-use. The present study investigated

  11. Glass-eel-stage American Eels respond to conspecific odor as a function of concentration

    Science.gov (United States)

    Schmucker, Andrew K.; Johnson, Nicholas; Galbraith, Heather S.; Li, Weiming

    2016-01-01

    The American Eel Anguilla rostrata has experienced staggering population declines in recent decades and is now the focus of restoration efforts. Studies have demonstrated that olfaction is critical to anguillid behavior and that glass eels (the life stage which migrates inland from saltwater to freshwater) are attracted to conspecific washings. We evaluated conspecific cueing as a potential mechanism for American Eel inland migration coordination by assessing (1) the affinity of glass eels to conspecific washings, (2) the concentration–response relationships, and (3) changes in responsiveness to washings during the glass eel-to-elver transition. In two-choice maze assays, glass eels were attracted to glass eel washings over a wide range of concentrations (0.20–0.40 g of glass eels·L−1·h−1), and a logarithmic function provided the best fit to the concentration–response relationship. When given a choice between two conspecific washings of higher and lower concentrations, the glass eels generally preferred the higher concentration. Responses to undiluted glass eel washings did not significantly differ among stage-3–7 glass eels, although stage-7 eels were not attracted to the washings, whereas the other stages were. Washing affinity remained similar over the course of several weeks. These results support aspects of the conspecific cueing hypothesis at the glass eel life stage under laboratory conditions, suggesting that conspecific cueing is an important component of migration coordination among juvenile American Eels and warrants additional study.

  12. First production of larvae using cryopreserved sperm: Effects of preservation temperature and cryopreservation on European eel sperm fertilization capacity

    DEFF Research Database (Denmark)

    Asturiano, J.F.; Sørensen, Sune Riis; Perez, L.

    2016-01-01

    Sperm cryopreservation is a useful tool in captive fish reproduction management, that is to synchronize gamete production, especially in the case of species as the European eel, where the time of female spawning readiness is unpredictable. Several protocols to cryopreserve sperm of this species...... have been described, but until recently fertilization trials were not feasible. This study evaluated the effect of cold storage of diluted sperm prior to fertilizations and tested whether a previously defined protocol for European eel sperm cryopreservation can be successfully applied in fertilization...... trials to produce viable offspring. In our experiment, the sperm motility was evaluated after the extraction and the best samples were selected and pooled. Until stripping of eggs and fertilization, diluted sperm samples were maintained at either 4 or 20°C, or cryopreserved, following existing protocols...

  13. Parasite communities in eels of the Island of Reunion (Indian Ocean): a lesson in parasite introduction.

    Science.gov (United States)

    Sasal, Pierre; Taraschewski, Horst; Valade, Pierre; Grondin, Henri; Wielgoss, Sébastien; Moravec, Frantisek

    2008-05-01

    Eel populations from the small rivers on the Island of Reunion (French Overseas Department in the Indian Ocean) were investigated with respect to the occurrence and abundance of helminths during the autumn of 2005. The native species Anguilla marmorata (n = 80), Anguilla bicolor (n = 23), and Anguilla mossambica (n = 15) were studied. Six species of helminths were identified, four of them having a definitely nonnative status. Furthermore, unidentified intra-intestinal juvenile cestodes and extra-intestinal encapsulated anisakid nematode larvae were present in a few eels. We found that the invasive swim bladder nematode Anguillicoloides (Anguillicola) crassus had been introduced into the island. Six specimens were collected, four from A. marmorata, one from A. bicolor and one from A. mossambica. The maximum intensity of infection was two worms. The other helminths also showed a low abundance. These species were the monogenean gill worms Pseudodactylogyrus anguillae and Pseudodactylogyrus bini and the intestinal parasites Bothriocephalus claviceps (Cestodes), Paraquimperia africana (Nematodes), and the acanthocephalan Acanthocephalus reunionensis Warner, Sasal, and Taraschewski, 2007. The latter species, found as intra-intestinal immatures, is thought to utilize amphibians as required hosts; its status, introduced or native, could not be determined. P. africana was described from A. mossambica in South Africa and has not been recorded outside Africa. The other species are known from populations of European and American eels. However, A. crassus and the two Pseudodactylogyrus species originate from East Asia, where they are indigenous parasites of Anguilla japonica. Both an assignment test based on seven specific microsatellite loci and subsequent sequencing of mitochondrial haplotypes of a partial fragment of cytochrome c oxidase 1 strongly suggest that the A. crassus may originated around the Baltic Sea. According to the results presented here, populations of the

  14. Changes in body weight and eye size in female European eel kept in fresh and salt water

    Directory of Open Access Journals (Sweden)

    Joanna Nowosad

    2014-05-01

    Full Text Available The eel is a catadromous fish which spends most of its life in freshwater and adults swim to the Sargasso Sea region to spawn. While preparing for the reproductive process, eels undergo a metamorphosis to become what is called silver eel; a process involving changes in the colour and weight of the body and an increase in the eye size. These are indicators of fish maturity and they facilitate the selection of fish for reproduction under controlled conditions. During this study, changes in the body weight (BW and eye size in female European eel were observed while being given weekly hormonal injections of 20 mg kg–1 carp pituitary homogenate and kept in 15°C freshwater and in 15°C saltwater with a salinity of 32-33‰. Fish kept in saltwater but not subjected to hormonal stimulation were used as a control group. Furthermore, after the experiment was finished, females in the control group were kept for next 5 months, with the same environmental parameters maintained. Differences between the treated groups were observed as early as week 4 of the experiment. An increase in fish BW was observed in fish kept both in salt and freshwater which were subjected to hormonal stimulation. On the other hand, changes in eye size were observed in the fish kept in saltwater, both in those hormonally stimulated and otherwise. The eye diameter in the fish kept in fresh after hormonal stimulation did not change significantly.

  15. The Pituitary Gland of the European Eel Reveals Massive Expression of Genes Involved in the Melanocortin System

    OpenAIRE

    Eirill Ager-Wick; Dirks, Ron P.; Erik Burgerhout; Rasoul Nourizadeh-Lillabadi; de Wijze, Daniëlle L.; Spaink, Herman P; van den Thillart, Guido E. E. J. M.; Katsumi Tsukamoto; Sylvie Dufour; Finn-Arne Weltzien; Henkel, Christiaan V.

    2013-01-01

    Hormones secreted from the pituitary gland regulate important processes such as development, growth and metabolism, reproduction, water balance, and body pigmentation. Synthesis and secretion of pituitary hormones are regulated by different factors from the hypothalamus, but also through feedback mechanisms from peripheral organs, and from the pituitary itself. In the European eel extensive attention has been directed towards understanding the different components of the brain-pituitary-gonad...

  16. Endocrine and metabolic responses of Anguilla anguilla L. caged in a freshwater-wetland (Pateira de Fermentelos-Portugal)

    Energy Technology Data Exchange (ETDEWEB)

    Teles, M. [Biology Department, Aveiro University, 3810-193 Aveiro (Portugal)]. E-mail: mteles@bio.ua.pt; Pacheco, M. [Biology Department, Aveiro University, 3810-193 Aveiro (Portugal)]. E-mail: mpacheco@bio.ua.pt; Santos, M.A. [Biology Department, Aveiro University, 3810-193 Aveiro (Portugal)]. E-mail: monteiro@bio.ua.pt

    2007-01-01

    The present short-term in situ study was carried out in a freshwater-wetland - Pateira de Fermentelos - considered an enlargement of Certima River, in the centre of Portugal. This ecosystem is an important fishing and recreation place, receiving effluents from different origins namely, electroplating industrial effluents containing heavy metals, domestic wastes, as well as pesticides and fertilizers resulting from agriculture activities. The aim of the present research work was to monitor the effects induced by the contaminants present in Pateira de Fermentelos water, using Anguilla anguilla L. (European eel) as a bioindicator. The eels were caged for 48 h at four Pateira de Fermentelos sites, differing in their distances to the main known pollution source (Certima River): A (close to the lagoon entrance), B, C and D (the farthest from the Certima River). A reference site was selected near the Certima river spring. The following parameters were measured: liver ethoxyresorufin-O-deethylase (EROD) and alanine transaminase (ALT) activities, plasma levels of cortisol, 17{beta}-estradiol (E{sub 2}), thyroid-stimulating-hormone (TSH), free thyroxine (T4), free triiodothyronine (T3), as well as glucose and lactate. The erythrocytic nuclear abnormalities (ENA) frequency was also scored as a genotoxicity indicator. The results revealed increased plasma cortisol and glucose concentrations at all exposure sites, displaying a similar response pattern. Plasma T3 showed a significant decrease only at site A when compared to reference site, whereas plasma E{sub 2} increased at sites B and D when compared to all the other sites, including reference site. The present results indicate the Pateira de Fermentelos water contamination, demonstrating the usefulness of the adopted strategy.

  17. First Production of Larvae Using Cryopreserved Sperm: Effects of Preservation Temperature and Cryopreservation on European Eel Sperm Fertilization Capacity.

    Science.gov (United States)

    Asturiano, J F; Sørensen, S R; Pérez, L; Lauesen, P; Tomkiewicz, J

    2016-08-01

    Sperm cryopreservation is a useful tool in captive fish reproduction management, that is to synchronize gamete production, especially in the case of species as the European eel, where the time of female spawning readiness is unpredictable. Several protocols to cryopreserve sperm of this species have been described, but until recently fertilization trials were not feasible. This study evaluated the effect of cold storage of diluted sperm prior to fertilizations and tested whether a previously defined protocol for European eel sperm cryopreservation can be successfully applied in fertilization trials to produce viable offspring. In our experiment, the sperm motility was evaluated after the extraction and the best samples were selected and pooled. Until stripping of eggs and fertilization, diluted sperm samples were maintained at either 4 or 20°C, or cryopreserved, following existing protocols. Fertilization of two egg batches was attempted. Diluted sperm caused a similar percentage of fertilized eggs and a similar number of embryos and larvae, independently of storage temperature (4 or 20°C). The cryopreserved sperm resulted in a lower percentage of fertilized eggs, but embryos developed and a few larvae ('cryolarvae') were obtained 55 h after fertilization in one of the two egg batches. This result evidences that the tested cryopreservation protocol is applicable for eel reproduction management, although improvements will be required to enhance fertilization success. © 2016 Blackwell Verlag GmbH.

  18. Impact of dietary fatty acids on muscle composition, liver lipids, milt composition and sperm performance in European eel

    DEFF Research Database (Denmark)

    Butts, Ian; Baeza, R.; Støttrup, Josianne

    2015-01-01

    In order for European eel aquaculture to be sustainable, the life cycle should be completed in captivity. Development of broodstock diets may improve the species' reproductive success in captivity, through the production of high-quality gametes. Here, our aim was to evaluate the influence......, and on the percentage of motile sperm. Here, our results suggest that the total volume of extractable milt is a DHA-dependent process, as we found the diets with the highest DHA levels induced the most milt while the diet with the lowest DHA level induced the least amount of milt. The diet with the highest level of ARA...... induced medium milt volumes but had the highest sperm motility. EPA also seems important for sperm quality parameters since diets with higher EPA percentages had a higher volume of milt and higher sperm motility. In conclusion, dietary fatty acids had an influence on fatty acids in the tissues of male eel...

  19. Plecospondylic spinal column in the eel Anguilla anguilla

    NARCIS (Netherlands)

    Stolk, A.

    1956-01-01

    Several cases of deformities in the spinal column were described in fishes, viz. lordosis in the bitterling Rhodeus amarus) by ROTH (1922), in the minnow (Phoxinus phoxinus) by ROTH (1922), in the pike (Esox lucius) by ROTH (1922) and PLEHN (1924); kyphosis in the toothcarps (Cyprinodontidae) by

  20. Occurrence of perfluorooctanesulfonate and perfluorooctanoic acid and histopathology in eels from north Italian waters.

    Science.gov (United States)

    Giari, Luisa; Guerranti, Cristiana; Perra, Guido; Lanzoni, Mattia; Fano, Elisa Anna; Castaldelli, Giuseppe

    2015-01-01

    A perfluorinated alkylated substances (PFAS) biomonitoring study was conducted in European eel (Anguilla anguilla) in Italy for the first time. Perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA) concentrations were assessed in the organs of 35 wild eels from two locations, the highly impacted Po River and the Comacchio Lagoon along the north-western Adriatic coast. PFAS were extracted by ion-pairing liquid extraction procedure and measured using high performance liquid chromatography with electrospray ionization tandem mass spectrometry. There were no significant differences in mean PFAS concentrations (p>0.05) between samples from the two sites. PFOS and PFOA were detectable (>0.4ngg(-1) wet weight, w.w) in 73% and 31% of the total samples, respectively. PFOS concentrations ranged from PFAS levels were observed in blood and the lowest in muscle. Histology showed macrophage aggregates and hepatocytic vacuolation in some liver samples. No tissue anomalies were seen in the gonads, suggesting no reproductive impairment. The PFAS contamination levels observed were comparable to, or lower than, those reported in fish in other European countries, seeming to indicate that PFAS pollution of the study area is not remarkable. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Hydrographic features of anguillid spawning areas: Potential signposts for migrating eels

    DEFF Research Database (Denmark)

    Schabetsberger, Robert; Miller, Michael J.; Dall'Olmo, Giorgio

    2016-01-01

    Catadromous anguillid eels (genus Anguilla) migrate from their freshwater or estuarine habitats to marine spawning areas. Evidence from satellite tagging studies indicates that tropical and temperate eel species exhibit pronounced diel vertical migrations, from between 150-300 m nighttime depths ...... possess acute sensory capabilities to detect these hydrographic features as potential signposts, guiding them to their spawning areas....

  2. Hydrographic features of anguillid spawning areas: Potential signposts for migrating eels

    DEFF Research Database (Denmark)

    Schabetsberger, Robert; Miller, Michael J.; Dall'Olmo, Giorgio

    2016-01-01

    Catadromous anguillid eels (genus Anguilla) migrate from their freshwater or estuarine habitats to marine spawning areas. Evidence from satellite tagging studies indicates that tropical and temperate eel species exhibit pronounced diel vertical migrations, from between 150-300 m nighttime depths ...

  3. Anguillicola crassus infection significantly affects the silvering related modifications in steady state mRNA levels in gas gland tissue of the European eel

    Directory of Open Access Journals (Sweden)

    Bernd ePelster

    2016-05-01

    Full Text Available Using Illumina sequencing, transcriptional changes occurring during silvering in swimbladder tissue of the European eel have been analyzed by comparison of yellow eel and silver eel tissue samples. Functional annotation analysis based on GO terms revealed significant expression changes in a number of genes related to the extracellular matrix, important for the control of gas permeability of the swimbladder, and to ROS (reactive oxygen species defense, important to cope with reactive oxygen species generated under hyperbaric oxygen partial pressures. Focusing on swimbladder tissue metabolism, levels of several mRNA species encoding glucose transport proteins were several-fold higher in silver eels, while enzymes of the glycolytic pathway were not affected. The significantly higher steady state level of a transcript encoding for membrane bound carbonic anhydrase, however, suggested that CO2 production in the pentose phosphate shunt and diffusion of CO2 was of particular importance in silver eel swimbladder. In addition, the mRNA level of a large number of genes related to immune response and to sexual maturation was significantly modified in the silver eel swimbladder. The modification of several processes related to protein metabolism and transport, cell cycle, and apoptosis suggested that these changes in swimbladder metabolism and permeability were achieved by increasing cell turn-over. The impact of an infection of the swimbladder with the nematode Anguillicola crassus has been assessed by comparing these expression changes with expression changes observed between uninfected yellow eel swimbladder tissue and infected silver eel swimbladder tissue. In contrast to uninfected silver eel swimbladder tissue, in infected tissue the mRNA level of several glycolytic enzymes was significantly elevated, and with respect to extracellular matrix, several mucin genes were many-fold higher in their mRNA level. Modification of many immune related genes and

  4. Kajian histologi ovarium ikan sidat Anguilla bicolor McClelland yang tertangkap di Segara Anakan Cilacap

    Directory of Open Access Journals (Sweden)

    Farida Nur Rachmawati

    2013-10-01

    Full Text Available The aim of this research was to know the histology of eel ovary, Anguilla bicolor McClelland, at various gonad developmental stage, which caught at Segara Anakan Cilacap. This research was conducted with survey method, there are 69 samples, about 47.1–76.5 cm in length and 143.6–982.5 g in weight. The parameters are gonad weight, histological structure and gonad maturation level. The result show that all of eels is female, which in yellow eel, and presilver stage. As the result, it can be concluded that Anguilla bicolor McClelland which caught at Segara Anakan Cilacap is immature, whereas mature stage of eel is not found.

  5. Fipronil and two of its transformation products in water and European eel from the river Elbe.

    Science.gov (United States)

    Michel, N; Freese, M; Brinkmann, M; Pohlmann, J-D; Hollert, H; Kammann, U; Haarich, M; Theobald, N; Gerwinski, W; Rotard, W; Hanel, R

    2016-10-15

    Fipronil is an insecticide which, based on its mode of action, is intended to be predominantly toxic towards insects. Fipronil bioaccumulates and some of its transformation products were reported to be similar or even more stable in the environment and to show an enhanced toxicity against non-target organisms compared to the parent compound. The current study investigated the occurrence of Fipronil and two of its transformation products, Fipronil-desulfinyl and Fipronil-sulfone, in water as well as muscle and liver samples of eels from the river Elbe (Germany). In water samples total concentrations of FIP, FIP-d and FIP-s ranged between 0.5-1.6ngL(-1) with FIP being the main component in all water samples followed by FIP-s and FIP-d. In contrast, FIP-s was the main component in muscle and liver tissues of eels with concentrations of 4.05±3.73ngg(-1) ww and 19.91±9.96ngg(-1) ww, respectively. Using a physiologically based toxicokinetic (PBTK) model for moderately hydrophobic organic chemicals, the different distributions of FIP, FIP-d and FIP-s in water and related tissue samples could be attributed to metabolic processes of eels. The measured concentrations in water of all analytes and their fractional distribution did not reflect the assumed seasonal application of FIP and it seems that the water was constantly contaminated with FIP, FIP-d and FIP-s. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Preliminary study about the detection of perfluoroalkyl substances in eel samples of Lake Garda by liquid chromatography tandem mass high resolution mass spectrometry (LC-HRMS.

    Directory of Open Access Journals (Sweden)

    Maria Nobile

    2017-05-01

    Full Text Available Perfluoroalkyl substances (PFASs are a large class of fluorinated aliphatic chemical of anthropogenic origin with high chemical stability even at high temperatures and in presence of alkalis, strong acids or oxidizing agents (Lau et al. 2004. All these characteristics make them no biodegradable and very persistent in the environment, associated with adverse health risks (Eriksen et al. 2010. Food, especially fish and other seafood, is considered the main source of exposure to PFASs (EFSA 2012. In this preliminary study we developed and validated a sensitive, selective and specific method by LC-HRMS Orbitrap to monitor the presence of 16 PFASs in eel (Anguilla Anguilla samples. The clean-up of the lyophilized samples consisted of a previous extraction step with acetonitrile to precipitate also proteins, followed by a purification step through Oasis® WAX SPE (Weak Anionic Exchange Solid Phase Extraction cartridges. The method applied to 45 farmed eel samples from Lake Garda showed the presence of several PFASs, up to 10 in the same eel, in the order of ng/g (Fig.1. The results provided a representative situation of the  PFASs contamination level of the lake, lower than those of others European countries (Hoff et al. 2005, Kwadijk et al. 2010.

  7. Dam removal increases American eel abundance in distant headwater streams

    Science.gov (United States)

    Hitt, Nathaniel P.; Eyler, Sheila; Wofford, John E.B.

    2012-01-01

    American eel Anguilla rostrata abundances have undergone significant declines over the last 50 years, and migration barriers have been recognized as a contributing cause. We evaluated eel abundances in headwater streams of Shenandoah National Park, Virginia, to compare sites before and after the removal of a large downstream dam in 2004 (Embrey Dam, Rappahannock River). Eel abundances in headwater streams increased significantly after the removal of Embrey Dam. Observed eel abundances after dam removal exceeded predictions derived from autoregressive models parameterized with data prior to dam removal. Mann–Kendall analyses also revealed consistent increases in eel abundances from 2004 to 2010 but inconsistent temporal trends before dam removal. Increasing eel numbers could not be attributed to changes in local physical habitat (i.e., mean stream depth or substrate size) or regional population dynamics (i.e., abundances in Maryland streams or Virginia estuaries). Dam removal was associated with decreasing minimum eel lengths in headwater streams, suggesting that the dam previously impeded migration of many small-bodied individuals (<300 mm TL). We hypothesize that restoring connectivity to headwater streams could increase eel population growth rates by increasing female eel numbers and fecundity. This study demonstrated that dams may influence eel abundances in headwater streams up to 150 river kilometers distant, and that dam removal may provide benefits for eel management and conservation at the landscape scale.

  8. The Anguilla spp. migration problem: 40 million years of evolution and two millennia of speculation

    DEFF Research Database (Denmark)

    Righton, D.; Aarestrup, K.; Jellyman, D.

    2012-01-01

    and the challenges of swimming at depth considered. The decline of Anguilla spp. across the world is an ongoing concern for fisheries and environmental managers. New developments in the knowledge of eel migration will, in addition to solving a centuries old mystery, probably help to identify how this decline might...

  9. Differences in brain gene transcription profiles advocate for an important role of cognitive function in upstream migration and water obstacles crossing in European eel.

    Science.gov (United States)

    Podgorniak, Tomasz; Milan, Massimo; Pujolar, Jose Marti; Maes, Gregory E; Bargelloni, Luca; De Oliveira, Eric; Pierron, Fabien; Daverat, Francoise

    2015-05-12

    European eel is a panmictic species, whose decline has been recorded since the last 20 years. Among human-induced environmental factors of decline, the impact of water dams during species migration is questioned. The main issue of this study was to pinpoint phenotypic traits that predisposed glass eels to successful passage by water barriers. The approach of the study was individual-centred and without any a priori hypothesis on traits involved in the putative obstacles selective pressure. We analyzed the transcription level of 14,913 genes. Transcriptome analysis of three tissues (brain, liver and muscle) from individuals sampled on three successive forebays separated by water obstacles indicated different gene transcription profiles in brain between the two upstream forebays. No differences in gene transcription levels were observed in liver and muscle samples among segments. A total of 26 genes were differentially transcribed in brain. These genes encode for, among others, keratins, cytokeratins, calcium binding proteins (S100 family), cofilin, calmodulin, claudin and thy-1 membrane glycoprotein. The functional analysis of these genes highlighted a putative role of cytoskeletal dynamics and synaptic plasticity in fish upstream migration. Synaptic connections in brain are solicited while eels are climbing the obstacles with poorly designed fishways. Successful passage by such barriers can be related to spatial learning and spatial orientation abilities when fish is out of the water.

  10. Kleptoparasitism and aggressiveness are influenced by standard metabolic rate in eels.

    Science.gov (United States)

    Geffroy, Benjamin; Bolliet, Valérie; Bardonnet, Agnès

    2016-04-01

    Kleptoparasitism refers to either interspecific or intraspecific stealing of food already procured by other species or individuals. Within a given species, individuals might differ in their propensity to use such a tactic, in a similar manner to which they differ in their general level of aggressiveness. Standard metabolic rate is often viewed as a proxy for energy requirements. For this reason, it should directly impact on both kleptoparasitism and aggressiveness when individuals have to share the same food source. In the present study we first assessed the standard metabolic rate (SMR) of 128 juvenile European eels (Anguilla anguilla) by the determination of oxygen consumption. We then tested how the SMR could influence agonistic behavior of individuals competing for food in three distinct trials evenly distributed over three months. We demonstrate that SMR positively correlates with attacks (sum of bite and push events) in all trials. Similarly SMR correlated positively with kleptoparasitism (food theft), but this was significant only for the third trial (month 3). To our knowledge, the present study is the first reporting a link between kleptoparasitism and SMR in a fish species. This has ecological implications owing to the fact that this species is characterized by an environmental sex determination linked to early growth rate. We discuss theses findings in the light of the producer-scrounger foraging game. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Data on the characterization of follicle-stimulating hormone monoclonal antibodies and localization in Japanese eel pituitary

    Directory of Open Access Journals (Sweden)

    Dae-Jung Kim

    2016-09-01

    In support of our recent publication, "Production and characterization of monoclonal antibodies against recombinant tethered follicle-stimulating hormone from Japanese eel Anguilla japonica" [1], it was important to characterize the specificity of eel follicle-stimulating hormone antibodies. Here, the production and ELISA system of these monoclonal antibodies are presented. The affinity-purified monoclonal antibodies specifically detected eel rec-FSH in ELISA and on western blots of rec-FSH produced from CHO cells. Immunohistochemical analysis revealed that FSH staining was specifically localized in the eel pituitary.

  12. Physiological properties of eel haemoglobin: hypoxic acclimation, phosphate effects and multiplicity.

    Science.gov (United States)

    Weber, R E; Lykkeboe, G; Johansen, K

    1976-02-01

    Unlike the whole body oxygen affinity, which adapts readily to environmental oxygen tensions, haemoglobins, prepared from normoxic- and hypoxic-accimated eels (Anguilla anguilla) show no adaptive changes in oxygenation properties or in multiplicity. Hypoxic acclimation is, howeveer, accompanied by a strong decrease in red cell nucleoside triphosphates, particularly guanosine triphospphate (GTP), which depresses oxygen affinity of the composite and component haemoglobins more strongly than does the concurring ATP. The effects of pH, temperature and salts on the oxygenation properties of the (isolated) haemoglobins are reported, discussed in relation to the varying environmetal conditions encountered by eels, and compared with data on American and Japanese eels (A. rostrata and A. juponica, respectively.

  13. Effects of oestradiol-enriched diet and of feeding with porcine testicular tissue on macroscopic gonadal sex in European eels

    DEFF Research Database (Denmark)

    Andersen, D.; Boetius, I.; Larsen, L.O.

    1996-01-01

    days there were 44% with female-gonads, 40% with male+female-gonads and 16% with male-gonads. Oestradiol thus had a feminizing effect, not only on morphologically undifferentiated gonads but also on morphologically differentiated male-gonads. The presence of sex steroid hormones or their precursors...... in porcine testicular tissue may also exert a feminizing influence. In all experiments the hormone-fed groups showed a tendency (not significant) towards increased growth rate. In small eels early rapid growth and differentiation of female-gonads were clearly correlated, both in hormone treated...

  14. Proceedings of a workshop on American Eel passage technologies

    Science.gov (United States)

    Haro, Alexander J.

    2013-01-01

    Recent concerns regarding a decline in recruitment of American eels (Anguilla rostrata) have prompted efforts to restore this species to historic habitats by providing passage for both upstream migrant juveniles and downstream migrant adults at riverine barriers, including low-head and hydroelectric dams (Castonguay et al. 1994, Haro et al. 2000). These efforts include development of management plans and stock assessment reviews in both the US and Canada (COSEWIC 2006, Canadian Eel Working Group 2009, DFO 2010, MacGregor et al. 2010, ASMFC 2000, ASMFC 2006, ASMFC 2008, Williams and Threader 2007), which target improvement of upstream and downstream passage for eels, as well as identification and prioritization of research needs for development of new and more effective passage technologies for American eels. Traditional upstream fish passage structures, such as fishways and fish lifts, are often ineffective passing juvenile eels, and specialized passage structures for this species are needed. Although designs for such passage structures are available and diverse (Knights and White 1998, Porcher 2002, FAO/DVWK 2002, Solomon and Beach 2004a,b, Environment Agency UK 2011), many biologists, managers, and engineers are unfamiliar with eel pass design and operation, or unaware of the technical options available for upstream eel passage, Better coordination is needed to account for eel passage requirements during restoration efforts for other diadromous fish species. Also, appropriately siting eel passes at hydropower projects is critical, and siting can be difficult and complex due to physical restrictions in access to points of natural concentrations of eels, dynamic hydraulics of tailrace areas, and presence of significant competing flows from turbine outfalls or spill. As a result, some constructed eel passes are sited poorly and may pass only a fraction of the number of eels attempting to pass the barrier. When sited and constructed appropriately, however, eel passes

  15. Assessing the freshwater distribution of yellow eel

    Directory of Open Access Journals (Sweden)

    Lasne É.

    2009-04-01

    Full Text Available In the global context of the decline in wild species, modeling the distribution of populations is a crucial aspect of ecological management. This can be a major challenge, especially for species, such as the European eel, that have complex life cycles, exhibit cryptic behavior, or migrate over long distances. A review of the literature suggests that eel size data could be used to assess and analyze freshwater distribution of eel. We argue that analyses based on small yellow eels (≤ 300 mm along the longitudinal course of rivers could provide a valuable tool for population monitoring. We propose a standardized catchment recruitment index and a colonization index based on the probability of occurrence (presence/absence data using logistic models for different size classes. The model developed here provides a convenient guide for assessing yellow eel stages in freshwater areas, and should have concrete applications for management of the species.

  16. Hypotonicity induced K+ and anion conductive pathways activation in eel intestinal epithelium

    DEFF Research Database (Denmark)

    Lionetto, M G; Giordano, M E; De Nuccio, F

    2005-01-01

    Control of cell volume is a fundamental and highly conserved physiological mechanism, essential for survival under varying environmental and metabolic conditions. Epithelia (such as intestine, renal tubule, gallbladder and gills) are tissues physiologically exposed to osmotic stress. Therefore......, the activation of 'emergency' systems of rapid cell volume regulation is fundamental in their physiology. The aim of the present work was to study the physiological response to hypotonic stress in a salt-transporting epithelium, the intestine of the euryhaline teleost Anguilla anguilla. Eel intestinal epithelium...

  17. The eel pollutant monitoring network in Flanders, Belgium. Results of 10 years monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Goemans, G.; Belpaire, C. [Inst. for Forestry and Game Management, Hoeilaart (Belgium)

    2004-09-15

    Since 1994 the Institute for Forestry and Game Management (IBW) has build out a pollutant monitoring network for public water bodies in Flanders (Belgium) using eel (Anguilla anguilla) as a biomonitor. The results presented here come from 2000 individually analysed eels originating from 260 different localities in Flanders, including rivers, canals, polder waters and closed water bodies. The sampling took place from 1994 to 2002. Eel is used for biomonitoring because it is a very fatty (strong lipophylic character of a.o. pesticides and PCB's), benthic, sedentary (during the yellow eel phase), long-living and widespread fish (in non-polluted as well as in polluted waters) and because of the absence of a seasonal effect through reproduction and its place on the trophic ladder. Some results represented are: (1) on 80 % of all sampled localities the Belgian PCB-standard for fish (75ng/g BW) is exceeded; (2) in the north-western part of Flanders is a severe lindanecontamination; (3) many long time prohibited pesticides are still found in considerable amounts in our food-chain; (4) several locations contain high to very high concentrations of brominated flame retardants. For several contaminants a comparison is made between the Flemish values and other values found in literature. The results of the Flemish eel pollutant monitoring network have initiated a catch-and-release obligation for eel in Flanders and for all fish on the 5 most polluted waters in Flanders.

  18. Oxidative stress and genotoxic effects in gill and kidney of Anguilla anguilla L. exposed to chromium with or without pre-exposure to beta-naphthoflavone.

    Science.gov (United States)

    Ahmad, Iqbal; Maria, V L; Oliveira, M; Pacheco, M; Santos, M A

    2006-09-19

    Fish in the aquatic environment can be subjected to a multipollution state and the occurrence of sequential exposures is an important aspect of eco-toxicological research. In this context, a preceding exposure can affect a toxic response to a subsequent exposure. Therefore, the current study was based on sequential exposures, viz. to a PAH-like compound (beta-naphthoflavone, BNF) followed by a heavy metal (chromium, Cr), focusing on the assessment of oxidative stress responses and their role in induction of genotoxicity. Oxidative stress responses in gill and kidney were investigated in European eel (Anguilla anguilla L.), and measured as lipid peroxidation (LPO), glutathione peroxidase (GPX), catalase (CAT) and glutathione S-transferase (GST) activity, and reduced glutathione (GSH) concentration, whereas genotoxicity was measured as DNA strand breakage. Fish were exposed for 24 h to two Cr concentrations (100 microM, 1 mM), with or without pre-exposure to BNF (2.7 microM, 24 h). In gill, a GSH decrease was observed along with loss of DNA integrity at all exposure conditions except at the lowest Cr concentration, showing a crucial role of GSH over genotoxicity. Moreover, sporadic induction of antioxidant enzymes was not effective in the protection against genotoxicity. However, a different mechanism seems to occur in kidney, since the loss of DNA integrity detected for all exposed groups was not accompanied by alterations in antioxidant levels. With regards to peroxidative damage, both organs showed an LPO increase after sequential exposure to BNF and 100 microM Cr. However, no association between LPO induction and antioxidant responses could be established, showing that LPO is not predictable solely on the basis of antioxidant depletion. The interference of BNF pre-exposure with the response of organs to Cr showed a marked dependence on the Cr concentration. Gill showed synergistic effects on LPO and GPX increase, as well as on CAT and GSH decrease for the lowest

  19. Retention and effects of miniature transmitters in juvenile American eels

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Robert P.; Janak, Jill; Liss, Stephanie A.; Brown, Richard S.; Deng, Zhiqun; Harnish, Ryan A.

    2017-11-01

    This study was conducted to assess the effects of a non-functional acoustic micro transmitter (tag) on survival, tag loss, and swimming ability of juvenile American eels (Anguilla rostrata). The transmitter was designed for implantation through a < 3 mm opening into the body cavity of anguilliform fishes without the need for sutures. American eels used for the swimming performance study were 113–175 mm (N = 120). There were two treatment groups (tagged and non-tagged), each treatment was split into six size groups of 10 mm for testing. Potential transmitter effects on swimming performance were examined by comparing critical swimming speeds (Ucrit an index of prolonged swimming performance) for tagged and non-tagged eels. There was no significant difference in Ucrit between tagged and non-tagged eels for all of the size groups tested. Median Ucrits for tagged eels ranged from 50.2 cm/s for the smallest group tested (113–119 mm) to 63.9 cm/s for fish 141–150 mm in length. Non-tagged group median Ucrits ranged from 47.2 cm/s for the smallest group to 66.9 cm/s for the 141–150 mm group. An additional 26 eels (115–208 mm) were tagged and held for 38 d (without undergoing swimming performance tests) to determine the effects on survival and tag loss. There was no mortality during the holding period and the majority of the tag loss occurred after 20 days post-tagging, which is the current projected life of the tag. Our results indicate that micro acoustic tags can be successfully implanted in juvenile American eels with no apparent impacts to swimming ability, and would be a viable option for examining eel movement patterns in river systems and near hydroelectric facilities.

  20. Some aspects on the reproductive cycle of European conger eel, Conger conger (Linnaeus, 1758 (Osteichthyes, Anguilliformes, Congridae captured from Western Algerian coasts: a histological description of spermatogenesis

    Directory of Open Access Journals (Sweden)

    Abi-ayad Sidi-Mohammed El-Amine

    2011-09-01

    Full Text Available The aim of this work was to study the annual reproductive cycle of European conger eel (Conger conger,Linnaeus, 1758 through analysis and description of spermatogenesis. A sample of 168 males was capturedbetween September 2008 and August 2009 from the Western coast of Algeria, from Béni Saf. Fish length andweight varied between 26.20-112 cm and 0.45-3.44 kg, respectively.Condition factors (K, gonadosomatic index (G.S.I. and hepatosomatic index (H.S.I. were calculatedmonthly. Factor K reached the minimum in August/September (0.10% corresponding to reproductive periodand a maximum in January (0.18%. Although G.S.I. values revealed to be statistically not significant, therewere two peaks for G.S.I., the first in March, denoting the beginning of spermatogenesis, and the second inAugust/September, indicating the reproduction period. H.S.I. reached a peak in December (1.90%, then thevalue decreased to a minimum in April.Histological analysis of testis allowed us to distinguish 5 stages summarized as follows: Stage 1:Spermatogonia A; Stage 2: Spermatogonia B; Stage 3: Spermatocytes and spermatids; Stage 4: Spermatocytes,spermatids and spermatozoa (cytodifferentiation of spermatids into spermatozoa; Stage 5: Spermatozoa(spermiogenesis or cytodifferentiation of spermatids into spermatozoa.

  1. Do North Atlantic eels show parallel patterns of spatially varying selection?

    DEFF Research Database (Denmark)

    Ulrik, Malene G.; Pujolar, Jose Martin; Ferchaud, Anne-Laure

    2014-01-01

    Background: The two North Atlantic eel species, the European and the American eel, represent an ideal system in which to study parallel selection patterns due to their sister species status and the presence of ongoing gene flow. A panel of 80 coding-gene SNPs previously analyzed in American eel w...

  2. Nitrite modulates contractility of teleost (Anguilla anguilla and Chionodraco hamatus, i.e. the Antarctic hemoglobinless icefish) and frog (Rana esculenta) hearts.

    Science.gov (United States)

    Cerra, M C; Angelone, T; Parisella, M L; Pellegrino, D; Tota, B

    2009-07-01

    Being the largest form of intravascular and tissue storage of nitric oxide (NO) and a signalling molecule itself, the nitrite anion (NO(2)(-)) has emerged as a key player in many biological processes. Since the heart is under an important NO-mediated autocrine-paracrine control, in mammals the cardiac effects of nitrite are under intensive investigation. In contrast, nothing is known in non-mammalian vertebrates. We evaluated nitrite influence on cardiac performance in the perfused beating heart of three different cold-blooded vertebrates, i.e. two teleost fishes, the temperate red-blooded Anguilla anguilla, the Antarctic stenotherm, hemoglobinless Chionodraco hamatus (icefish), and the frog Rana esculenta. We showed that, under basal conditions, in all animals nitrite influences cardiac mechanical performance, inducing negative inotropism in eel and frog, while being a positive inotrope in C. hamatus. In all species, these responses parallel the inotropic effects of authentic NO. We also demonstrated that the nitrite-dependent inotropic effects are i) dependent from NO synthase (NOS) activity in fish; ii) sensitive to NO scavenging in frog; iii) cGMP/PKG-dependent in both eel and frog. Results suggest that nitrite is an integral physiological source of NO and acts as a signalling molecule in lower vertebrate hearts, exerting relevant inotropic actions through different species-specific mechanisms.

  3. Eel green fluorescent protein is associated with resistance to oxidative stress.

    Science.gov (United States)

    Funahashi, Aki; Komatsu, Masaharu; Furukawa, Tatsuhiko; Yoshizono, Yuki; Yoshizono, Hikari; Orikawa, Yasuhiro; Takumi, Shota; Shiozaki, Kazuhiro; Hayashi, Seiichi; Kaminishi, Yoshio; Itakura, Takao

    2016-01-01

    Green fluorescent protein (GFP) from eel (Anguilla japonica) muscle (eelGFP) is unique in the vertebrates and requires bilirubin as a ligand to emit fluorescence. This study was performed to clarify the physiological function of the unique GFP. Investigation of susceptibility to oxidative stress was carried out using three types of cell lines including jellyfish (Aequorea coerulescens) GFP (jfGFP)-, or eel GFP (eelGFP)-expressing HEK293 cells, and control vector-transfected HEK293 cells. Binding of eelGFP to bilirubin was confirmed by the observation of green fluorescence in HEK293-eelGFP cells. The growth rate was compared with the three types of cells in the presence or absence of phenol red which possessed antioxidant activity. The growth rates of HEK293-CV and HEK293-jfGFP under phenol red-free conditions were reduced to 52 and 31% of those under phenol red. Under the phenol red-free condition, HEK293-eelGFP had a growth rate of approximately 70% of the phenol red-containing condition. The eelGFP-expressing cells were approximately 2-fold resistant to oxidative stress such as H2O2 exposure. The fluorescence intensity partially decreased or disappeared after exposure to H2O2, and heterogeneous intensity of fluorescence was also observed in isolated eel skeletal muscle cells. These results suggested eelGFP, but not jfGFP, coupled with bilirubin provided the antioxidant activity to the cells as compared to non-bound free bilirubin. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Farming different species in RAS in Nordic countries: Current status and future perspectives

    DEFF Research Database (Denmark)

    Dalsgaard, Anne Johanne Tang; Lund, Ivar; Thorarinsdottir, Ragnheidur

    2013-01-01

    (Oncorhynchus mykiss), European eel (Anguilla anguilla), pike perch (Stizostedion lucioperca), Arctic char (Salvelinus alpinus), sturgeon (order Acipenseriformes), Nile tilapia (Oreochromis niloticus), and European lobster (Homarus gammarus). High capital costs are one of the biggest challenges to sustainable...

  5. To what extent are hepatic concentrations of heavy metals in Anguilla anguilla at a site in a contaminated estuary related to body size and age and reflected in the metallothionein concentrations?

    Energy Technology Data Exchange (ETDEWEB)

    Bird, D.J. [Faculty of Applied Sciences, University of the West of England, Bristol, BS16 1QY (United Kingdom)], E-mail: david.bird@uwe.ac.uk; Rotchell, J.M. [Department of Biology and Environmental Science, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG (United Kingdom)], E-mail: j.rotchell@sussex.ac.uk; Hesp, S.A. [Centre for Fish and Fisheries Research, School of Biological Sciences and Biotechnology, Division of Science and Engineering, Murdoch University, South Street, Perth, Western Australia 6150 (Australia)], E-mail: ahesp@murdoch.edu.au; Newton, L.C. [Faculty of Applied Sciences, University of the West of England, Bristol, BS16 1QY (United Kingdom)], E-mail: lyn.newton@uwe.ac.uk; Hall, N.G. [Centre for Fish and Fisheries Research, School of Biological Sciences and Biotechnology, Division of Science and Engineering, Murdoch University, South Street, Perth, Western Australia 6150 (Australia)], E-mail: n.hall@murdoch.edu.au; Potter, I.C. [Centre for Fish and Fisheries Research, School of Biological Sciences and Biotechnology, Division of Science and Engineering, Murdoch University, South Street, Perth, Western Australia 6150 (Australia)], E-mail: i.potter@murdoch.edu.au

    2008-02-15

    We explored how hepatic [metal]s in Anguilla anguilla at a contaminated estuarine site are influenced by body size, age and season, and the extent that [Cu], [Cd] and [Zn]s are reflected in [metallothionein (MT)]s. Although each [metal] and [MT] increased significantly with length, weight and age, those biotic variables explained <10% of the variation in each [metal] and only 11-16% for [MT]. Seasonal changes in [Cu] and [Cd] were paralleled by [MT]. The variation in [MT] explained by Cu (42%) was greater than by Zn (16%) and Cd (13%), and seasonally lay between 43 and 69% for those metals collectively. Thus, hepatic [MT] in eels is closely correlated with hepatic [heavy metal]s. However, the great variability among [MT]s for eels of similar sizes and ages, which reflects marked variability in hepatic [heavy metal]s, means that this variable reflects imprecisely the contamination level at a particular site. - Hepatic [Cu], [Cd], [Zn] and [MT] in eels varies greatly with size, age and season.

  6. Bite by moray eel

    Directory of Open Access Journals (Sweden)

    JP Barreiros

    2008-01-01

    Full Text Available Injuries caused by moray eels are not a common problem, but are distributed throughout the globe, affecting mainly fishermen while manipulating hooked or netted fish. On a lesser scale, scuba divers and snorkelers, practicing or not spear fishing, are occasional victims of bites. With more than 185 species distributed among 15 genera, mostly in tropical to temperate shallow water, moray eels easily come into contact with humans and occasional injuries are not uncommon. The current study reports one case of moray eel bite and discusses the circumstances in which the accident happened, as well as wound evolution and therapy.

  7. Neurotransmitters and putative neuromodulators in the gut of Anguilla anguilla (L.. Localizations in the enteric nervous and endocrine systems

    Directory of Open Access Journals (Sweden)

    A Veggetti

    2009-12-01

    Full Text Available The gut of silver eels (Anguilla anguilla L. was investigated in order to describe both the cholinergic and adrenergic intramural innervations, and the localization of possible accessory neuromediators. Histochemical reactions for the demonstration of nicotinamide adenine dinucleotide phosphate, reduced form-(NADPH-diaphorase and acetylcholinesterese (AChEase were performed, as well as the immunohistochemical testing of tyrosine hydroxylase, met-enkephalin, substance P, calcitonin gene-related peptide (CGRP, bombesin, vasoactive intestinal peptide (VIP, neuropeptide Y (NPY, somatostatin, cholecystokinin-octapeptide (CCK-8, serotonin, cholineacetyltransferase. The results evidenced a different pattern in comparison with other vertebrates, namely mammals, and with other fish. Both NADPH-diaphorase and AChEase activities were histochemically detected all along the gut in the myenteric plexus, the inner musculature and the propria-submucosa. Tyrosine hydroxylase immunoreactivity was observed in the intestinal tract only, both in the myenteric plexus and in the inner musculature. Several neuropeptides (metenkephalin, CGRP, bombesin, substance P, VIP, NPY, somatostatin were, in addition, detected in the intramural innervation; some of them also in epithelial cells of the diffuse endocrine system (met-enkephalin, substance P, NPY, somatostatin. Serotonin was only present in endocrine cells. Tyrosine hydroxylase immunoreactivity was present in localizations to those of similar NADPHdiaphorase- reactivity, and in the same nerve bundles in which substance P- and CGRP-likeimmunoreactivities were detectable in the intestinal tract. In addition, NADPH-diaphorase-reactive neurons showed an anatomical relationship with AChEase-reactive nerve terminals, and a similar relationship existed between the latter and substance P-like immunoreactivity.

  8. Crucial role of cytoskeleton reorganization in the negative inotropic effect of chromogranin A-derived peptides in eel and frog hearts.

    Science.gov (United States)

    Mazza, Rosa; Mannarino, Cinzia; Imbrogno, Sandra; Barbieri, Sandra Francesca; Adamo, Cristina; Angelone, Tommaso; Corti, Angelo; Tota, Bruno

    2007-02-01

    Vasostatins (VSs), i.e. the main biologically active peptides generated by the proteolytic processing of chromogranin A (CGA) N-terminus, exert negative inotropism in vertebrate hearts. Here, using isolated working eel (Anguilla anguilla) and frog (Rana esculenta) heart preparations, we have studied the role of the cytoskeleton in the VSs-mediated inotropic response. In both eel and frog hearts, VSs-mediated-negative inotropy was abolished by treatment with inhibitors of cytoskeleton reorganization, such as cytochalasin-D (eel: 10 nM; frog: 1 nM), an inhibitor of actin polymerisation, wortmannin (0.01 nM), an inhibitor of PI3-kinase (PI3-K)/protein kinase B (Akt) signal-transduction cascade, butanedione 2-monoxime (BDM) (eel: 100 nM; frog: 10 nM), an antagonist of myosin ATPase, and N-(6-aminohexil)-5-chloro-1-naphthalenesulfonamide (W7) (eel: 100 nM; frog: 1 nM), a calcium-calmodulin antagonist. These results demonstrate that changes in cytoskeletal dynamics play a crucial role in the negative inotropic influence of VSs on eel and frog hearts.

  9. The phylogenetics of Anguillicolidae (Nematoda: Anguillicoloidea, swimbladder parasites of eels

    Directory of Open Access Journals (Sweden)

    Laetsch Dominik R

    2012-05-01

    Full Text Available Abstract Background Anguillicolidae Yamaguti, 1935 is a family of parasitic nematode infecting fresh-water eels of the genus Anguilla, comprising five species in the genera Anguillicola and Anguillicoloides. Anguillicoloides crassus is of particular importance, as it has recently spread from its endemic range in the Eastern Pacific to Europe and North America, where it poses a significant threat to new, naïve hosts such as the economic important eel species Anguilla anguilla and Anguilla rostrata. The Anguillicolidae are therefore all potentially invasive taxa, but the relationships of the described species remain unclear. Anguillicolidae is part of Spirurina, a diverse clade made up of only animal parasites, but placement of the family within Spirurina is based on limited data. Results We generated an extensive DNA sequence dataset from three loci (the 5' one-third of the nuclear small subunit ribosomal RNA, the D2-D3 region of the nuclear large subunit ribosomal RNA and the 5' half of the mitochondrial cytochrome c oxidase I gene for the five species of Anguillicolidae and used this to investigate specific and generic boundaries within the family, and the relationship of Anguillicolidae to other spirurine nematodes. Neither nuclear nor mitochondrial sequences supported monophyly of Anguillicoloides. Genetic diversity within the African species Anguillicoloides papernai was suggestive of cryptic taxa, as was the finding of distinct lineages of Anguillicoloides novaezelandiae in New Zealand and Tasmania. Phylogenetic analysis of the Spirurina grouped the Anguillicolidae together with members of the Gnathostomatidae and Seuratidae. Conclusions The Anguillicolidae is part of a complex radiation of parasitic nematodes of vertebrates with wide host diversity (chondrichthyes, teleosts, squamates and mammals, most closely related to other marine vertebrate parasites that also have complex life cycles. Molecular analyses do not support the recent

  10. Development and validation of a real-time PCR assay for the detection of anguillid herpesvirus 1

    NARCIS (Netherlands)

    Beurden, van S.J.; Voorbergen-Laarman, H.A.; Roozenburg-Hengst, R.E.M.; Tellingen, van Jurjen; Haenen, O.L.M.; Engelsma, M.Y.

    2016-01-01

    Anguillid herpesvirus 1 (AngHV1) causes a haemorrhagic disease with increased mortality in wild and farmed European eel, Anguilla anguilla (L.) and Japanese eel Anguilla japonica, Temminck & Schlegel). Detection of AngHV1 is currently based on virus isolation in cell culture, antibody-based

  11. Development and validation of a real-time PCR assay for the detection of anguillid herpesvirus 1

    NARCIS (Netherlands)

    van Beurden, S J; Voorbergen-Laarman, M A; Roozenburg, I; van Tellingen, J; Haenen, O L M; Engelsma, M Y

    2015-01-01

    Anguillid herpesvirus 1 (AngHV1) causes a haemorrhagic disease with increased mortality in wild and farmed European eel, Anguilla anguilla (L.) and Japanese eel Anguilla japonica, Temminck & Schlegel). Detection of AngHV1 is currently based on virus isolation in cell culture, antibody-based typing

  12. Transcriptome sequencing based annotation and homologous evidence based scaffolding of Anguilla japonica draft genome.

    Science.gov (United States)

    Liu, Yu-Chen; Hsu, Sheng-Da; Chou, Chih-Hung; Huang, Wei-Yun; Chen, Yu-Hung; Liu, Chia-Yu; Lyu, Guan-Jay; Huang, Shao-Zhen; Aganezov, Sergey; Alekseyev, Max A; Hsiao, Chung-Der; Huang, Hsien-Da

    2016-01-11

    Anguilla japonica (Japanese eel) is currently one of the most important research subjects in eastern Asia aquaculture. Enigmatic life cycle of the organism makes study of artificial reproduction extremely limited. Henceforth genomic and transcriptomic resources of eels are urgently needed to help solving the problems surrounding this organism across multiple fields. We hereby provide a reconstructed transcriptome from deep sequencing of juvenile (glass eels) whole body samples. The provided expressed sequence tags were used to annotate the currently available draft genome sequence. Homologous information derived from the annotation result was applied to improve the group of scaffolds into available linkage groups. With the transcriptome sequence data combined with publicly available expressed sequence tags evidences, 18,121 genes were structurally and functionally annotated on the draft genome. Among them, 3,921 genes were located in the 19 linkage groups. 137 scaffolds covering 13 million bases were grouped into the linkage groups in additional to the original partial linkage groups, increasing the linkage group coverage from 13 to 14%. This annotation provide information of the coding regions of the genes supported by transcriptome based evidence. The derived homologous evidences pave the way for phylogenetic analysis of important genetic traits and the improvement of the genome assembly.

  13. Pengaruh pemberian pakan berupa campuran pelet ikan, ulat tepung (Tenebrio molitor, dan ganggang merah (Gracilaria foliifera terhadap pertumbuhan dan kelulushidupan ikan sidat (Anguilla bicolor

    Directory of Open Access Journals (Sweden)

    MUHAMMAD A. AZIZ HENDITAMA

    2015-05-01

    Full Text Available Henditama MAA, Harini M, Budiharjo A. 2015. The effect of giving mixtured feed of fish pellet, mealworm (Tenebrio molitor and red algae (Gracilaria foliifera to the growth and survival rate of eel (Anguilla bicolor. Bioteknologi 12: 22-28. High demand of eels (Anguilla bicolor in the world has not followed by the capability of domestic production. The purpose of this research are to determine the effect and the precise composition of the feed mixture in the form of fish pellets, mealworms (Tenebrio molitor, red algae (Gracilaria foliifera to the growth and survival rate of eels. This research used completely randomized design with four variations of mixtured feed in the form of fish pellet, mealworms, and red algae specifically P1 (100% ; 0% ; 0%, P2 (75% ; 20% ; 5%, P3 (50% ; 45% ; 5%, P4 (25% ; 70% ; 5%. This research also has been done in 90 days with feeding in twice a day. The data of growth, survival rate, and water quality was collected once a week. The data result has been analized by ANOVA. The data result showed that have a real different to continue to the next analysis of DMRT with test level 5% to locate the differences between treatments. The eels growth after feeding a mixture feed in the form of fish pellets, mealworms, and red alga, specifically: P1 (K 26.3167 gram; P2 20.3167 gram; P3 28.2500 gram; and P4 22.0000 gram. The eels survival rate, specifically P1 (K 26.67%; P2 33.33%; P3 30%; dan P4 26.67%. Furthemore, the exact composition that give the best effect of growth and survival rate to eels is 50% fish pellets, 45% mealworms and 5% red alga.

  14. Piscivory and trophic position of Anguilla anguilla in two lakes: importance of macrozoobenthos density

    DEFF Research Database (Denmark)

    Dorner, H.; Skov, Christian; Berg, Søren

    2009-01-01

    and no submerged macrophytes). The density of macrozoobenthos was higher in LV (3500 individuals m(-2)) than in LGV (1500 individuals m(-2)). The abundance of small prey fishes (40-99 mm L-T) was highest in LV. In LV, A. anguilla fed on macrozoobenthos, in particular, chironomid larvae. In LGV, A. anguilla used...... fishes as the main food component. Stable isotope analyses confirmed the stomach contents dietary results. The estimated mean +/- s.d. trophic positions of A. anguilla in LGV (3 center dot 7 +/- 0 center dot 2) was one level higher than those of fish in LV (2 center dot 7 +/- 0 center dot 2). Based...

  15. Genetic and migratory evidence for sympatric spawning of tropical Pacific eels from Vanuatu

    DEFF Research Database (Denmark)

    Schabetsberger, R.; Økland, F.; Kalfatak, D.

    2015-01-01

    transmitters. Based on morphological evidence, 32 eels were identified as Anguilla marmorata, 45 as A. megastoma and 7 as A. obscura. Thirteen of these eels possessed a mitochondrial DNA sequence (control region, 527 bp) or nuclear haplotype (GTH2b, 268 bp) conflicting with their species designation....... megastoma. One A. marmorata and one A. megastoma migrated 634 and 874 km, respectively, towards the border between the South Equatorial Current and the South Equatorial Counter Current. Both species descended from around 200 m depth at night to 750 m during the day. Lunar cycle affected the upper limit...... of migration depths of both species. The tags remained attached for 3 and 5 mo and surfaced...

  16. Micro-PIXE study of whole otolith of Anguilla japonica at elver stage

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Y. [Applied Ion Beam Physics Laboratory, Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Guo, H.; Wei, K.; Tang, W. [Institute of Life Science, Shanghai Fisheries University, Shanghai 200090 (China); Satoh, T.; Ohkubo, T.; Yamazaki, A.; Takano, K.; Kamiya, T. [Takasaki Advanced Radiation Research Institute, JAEA, Gunma 370-1292 (Japan); Shen, H., E-mail: haoshen@fudan.edu.c [Applied Ion Beam Physics Laboratory, Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Yang, M.; Mi, Y. [Applied Ion Beam Physics Laboratory, Institute of Modern Physics, Fudan University, Shanghai 200433 (China)

    2010-06-15

    Strontium and calcium contents, within the otolith of Anguilla japonica, were measured by external micro-PIXE. According to the measured metamorphic checks, each otolith was divided into three stages. Comparing with the Sr:Ca ratios in stage 2, the ratios in stage 1 had two different trends. Among these fish, it may reflect their maternal condition was not the same. The ratios in stage 3 which was corresponding to the estuarine habitat were smaller than that in any other stage which was corresponding to the ocean habitat in each otolith. Suggested by our results, the eels from the spawning site may separate into two groups when they are near to the south of Taiwan, and then move to the different estuaries in China. It could be proposed that, in general, the migration direction is from south to north along the east coast in China.

  17. Passage of downstream migrant American eels through an airlift-assisted deep bypass

    Science.gov (United States)

    Haro, Alexander J.; Watten, Barnaby J.; Noreika, John

    2016-01-01

    Traditional downstream guidance and bypass facilities for anadromous fishes (i.e., surface bypasses, surface guidance structures, and behavioral barriers) have frequently been ineffective for anguillid eels. Because eels typically spend the majority of their time near the bottom in the vicinity of intake structures, deep bypass structures with entrances near the bottom hold promise for increased effectiveness, thereby aiding in the recovery of this important species. A new design of a deep bypass system that uses airlift technology (the Conte Airlift Bypass) to induce flow in a bypass pipe was tested in a simulated intake entrance environment under controlled laboratory conditions. Water velocities of 0.9–1.5 m s−1 could be generated at the bypass entrance (opening with 0.073 m2 area), with corresponding flows through the bypass pipe of 0.07–0.11 m3 s−1. Gas saturation and hydrostatic pressure within the bypass pipe did not vary appreciably from a control (no air) condition under tested airflows. Migratory silver-phase American eels (Anguilla rostrata) tested during dark conditions readily located, entered, and passed through the bypass; initial avoidance rates (eels approaching but not entering the bypass entrance) were lower at higher entrance velocities. Eels that investigated the bypass pipe entrance tended to enter headfirst, but those that then exited the pipe upstream did so more frequently at lower entrance velocities. Eels appeared to swim against the flow while being transported downstream through the pipe; median transit times through the bypass for each test velocity ranged from 5.8 to 12.2 s, with transit time decreasing with increasing entrance velocity. Eels did not show strong avoidance of the vertical section of the pipe which contained injected air. No mortality or injury of bypassed eels was observed, and individual eels repeatedly passed through the bypass at rates of up to 40 passes per hour, suggesting that individuals do not

  18. Recreational fishery in the Netherlands: catch estimates of cod (Gadus morhua) and eel (anguilla anguilla) in 2010

    NARCIS (Netherlands)

    Hammen, van der T.; Graaf, de M.

    2012-01-01

    De Nederlandse overheid zijn verplichtingen opgelegd door de Europese Commissie met betrekking tot het rapporteren van vangsten door recreatieve vissers. Voor Nederland geldt deze verplichting alleen voor kabeljauw en aal. In opdracht van het Ministerie van Economische Zaken, Landbouw en Innovatie

  19. How the body contributes to the wake in undulatory fish swimming: Flow fields of a swimming eel (Anguilla anguilla)

    NARCIS (Netherlands)

    Müller, Ulrike K.; Smit, Joris; Stamhuis, Eize J.; Videler, John J.

    2001-01-01

    Undulatory swimmers generate thrust by passing a transverse wave down their body. Thrust is generated not just at the tail, but also to a varying degree by the body, depending on the fish's morphology and swimming movements. To examine the mechanisms by which the body in particular contributes to

  20. Angiotensin II dependent cardiac remodeling in the eel Anguilla anguilla involves the NOS/NO system

    DEFF Research Database (Denmark)

    Filice, Mariacristina; Amelio, Daniela; Garofalo, Filippo

    2017-01-01

    of AT2 receptor and a negative modulation of the ERK1-2 pathway, together with a decrease in nitrite concentration, indicative of a reduced Nitric Oxide Synthase (NOS)-dependent NO production. Moreover, immunolocalization revealed, particularly on the endocardial endothelium (EE) of AngII-treated hearts...

  1. An evaluation of silver-stage American Eel conspecific chemical cueing during outmigration

    Science.gov (United States)

    Schmucker, Andrew K.; Johnson, Nicholas S.; Galbraith, Heather S.; Li, Weiming

    2017-01-01

    American Eel Anguilla rostrata abundance has declined in recent decades, in part because sexually maturing, silver-stage adults, outmigrating from freshwater to oceanic spawning grounds, encounter migratory blockades or perish when passing through active hydroelectric turbines. To help improve downstream passage effectiveness and increase survival rates, the role of silver-stage American Eel conspecific chemical cueing during outmigration was investigated using a new type of bioassay. Inside a laboratory flume, downstream-swimming eels were exposed to both live (putative attractant) and dead (putative repellent) conspecific washings to determine whether their trajectory of downstream movement, level of activity, or time spent inside targeted areas of the arena changed after exposure. Silver eels were not attracted to or repulsed by either odor, as none of five scoring metrics indicated a behavioral response. Results did not support the hypothesis that conspecific chemical cueing is a mechanism for downstream migration coordination or danger avoidance; however responses may not have been readily apparent in this type of assay. Fisheries managers may opt to focus future research on more feasible restoration efforts using alternate experimental designs to remedy this ecological issue.

  2. The mechanism for primordial germ-cell migration is conserved between Japanese eel and zebrafish.

    Directory of Open Access Journals (Sweden)

    Taiju Saito

    Full Text Available Primordial germ cells (PGCs are segregated and specified from somatic cells during early development. These cells arise elsewhere and have to migrate across the embryo to reach developing gonadal precursors. Several molecules associated with PGC migration (i.e. dead-end, nanos1, and cxcr4 are highly conserved across phylum boundaries. However, since cell migration is a complicated process that is regulated spatially and temporally by multiple adaptors and signal effectors, the process is unlikely to be explained by these known genes only. Indeed, it has been shown that there are variations in PGC migration pattern during development among teleost species. However, it is still unclear whether the actual mechanism of PGC migration is conserved among species. In this study, we studied the migration of PGCs in Japanese eel (Anguilla japonica embryos and tested the migration mechanism between Japanese eel and zebrafish (Danio rerio for conservation, by transplanting eel PGCs into zebrafish embryos. The experiments showed that eel PGCs can migrate toward the gonadal region of zebrafish embryos along with endogenous PGCs, even though the migration patterns, behaviors, and settlements of PGCs are somewhat different between these species. Our results demonstrate that the migration mechanism of PGCs during embryonic development is highly conserved between these two distantly related species (belonging to different teleost orders.

  3. Low levels of persistent organic pollutants (POPs) in New Zealand eels reflect isolation from atmospheric sources

    Energy Technology Data Exchange (ETDEWEB)

    Holmqvist, Niklas [Department of Ecology, Section of Ecotoxicology, Ecology Building, Lund University, SE-223 62 Lund (Sweden)]. E-mail: niklas.holmqvist@ekol.lu.se; Stenroth, Patrik [Department of Ecology, Section of Limnology, Ecology Building, Lund University, SE-223 62 Lund (Sweden); Berglund, Olof [Department of Ecology, Section of Ecotoxicology, Ecology Building, Lund University, SE-223 62 Lund (Sweden); Nystroem, Per [Department of Ecology, Section of Limnology, Ecology Building, Lund University, SE-223 62 Lund (Sweden); Olsson, Karin [Department of Ecology, Section of Limnology, Ecology Building, Lund University, SE-223 62 Lund (Sweden); Jellyman, Don [National Institute of Water and Atmospheric Research Ltd., PO Box 8602, Christchurch (New Zealand); McIntosh, Angus R. [School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Larsson, Per [Department of Ecology, Section of Ecotoxicology, Ecology Building, Lund University, SE-223 62 Lund (Sweden)

    2006-06-15

    Polychlorinated biphenyls (PCBs) and organic pesticides (i.e., DDTs) were measured in long finned eels (Anguilla dieffenbachii) in 17 streams on the west coast of South Island, New Zealand. Very low levels of PCBs and low levels of ppDDE were found. The concentrations of PCBs and ppDDE were not correlated within sites indicating that different processes determined the levels of the two pollutants in New Zealand eels. The PCBs probably originate from atmospheric transport, ppDDE levels are determined by land use and are higher in agriculture areas. The low contamination level of these aquatic systems seems to be a function of a low input from both long and short-range transport as well as few local point sources. No correlation could be found between lipid content and persistent organic pollutants (POPs) concentration (as shown in previous studies) in the eels which could be explained by low and irregular intake of the pollutants. - Low levels of PCBs found in New Zealand eels reflect isolation from atmospheric sources while DDTs levels are determined by land use.

  4. Spawning sites of the Japanese eel in relation to oceanographic structure and the West Mariana Ridge.

    Directory of Open Access Journals (Sweden)

    Jun Aoyama

    Full Text Available The Japanese eel, Anguilla japonica, spawns within the North Equatorial Current that bifurcates into both northward and southward flows in its westward region, so its spawning location and larval transport dynamics seem important for understanding fluctuations in its recruitment to East Asia. Intensive research efforts determined that Japanese eels spawn along the western side of the West Mariana Ridge during new moon periods, where all oceanic life history stages have been collected, including eggs and spawning adults. However, how the eels decide where to form spawning aggregations is unknown because spawning appears to have occurred at various latitudes. A salinity front formed from tropical rainfall was hypothesized to determine the latitude of its spawning locations, but an exact spawning site was only found once by collecting eggs in May 2009. This study reports on the collections of Japanese eel eggs and preleptocephali during three new moon periods in June 2011 and May and June 2012 at locations indicating that the distribution of lower salinity surface water or salinity fronts influence the latitude of spawning sites along the ridge. A distinct salinity front may concentrate spawning south of the front on the western side of the seamount ridge. It was also suggested that eels may spawn at various latitudes within low-salinity water when the salinity fronts appeared unclear. Eel eggs were distributed within the 150-180 m layer near the top of the thermocline, indicating shallow spawning depths. Using these landmarks for latitude (salinity front, longitude (seamount ridge, and depth (top of the thermocline to guide the formation of spawning aggregations could facilitate finding mates and help synchronize their spawning.

  5. Rhodopsin gene copies in Japanese eel originated in a teleost-specific genome duplication.

    Science.gov (United States)

    Nakamura, Yoji; Yasuike, Motoshige; Mekuchi, Miyuki; Iwasaki, Yuki; Ojima, Nobuhiko; Fujiwara, Atushi; Chow, Seinen; Saitoh, Kenji

    2017-01-01

    Gene duplication is considered important to increasing the genetic diversity in animals. In fish, visual pigment genes are often independently duplicated, and the evolutionary significance of such duplications has long been of interest. Eels have two rhodopsin genes (rho), one of which (freshwater type, fw-rho) functions in freshwater and the other (deep-sea type, ds-rho) in marine environments. Hence, switching of rho expression in retinal cells is tightly linked with eels' unique life cycle, in which they migrate from rivers or lakes to the sea. These rho genes are apparently paralogous, but the timing of their duplication is unclear due to the deep-branching phylogeny. The aim of the present study is to elucidate the evolutionary origin of the two rho copies in eels using comparative genomics methods. In the present study, we sequenced the genome of Japanese eel Anguilla japonica and reconstructed two regions containing rho by de novo assembly. We found a single corresponding region in a non-teleostean primitive ray-finned fish (spotted gar) and two regions in a primitive teleost (Asian arowana). The order of ds-rho and the neighboring genes was highly conserved among the three species. With respect to fw-rho, which was lost in Asian arowana, the neighboring genes were also syntenic between Japanese eel and Asian arowana. In particular, the pattern of gene losses in ds-rho and fw-rho regions was the same as that in Asian arowana, and no discrepancy was found in any of the teleost genomes examined. Phylogenetic analysis supports mutual monophyly of these two teleostean synteny groups, which correspond to the ds-rho and fw-rho regions. Syntenic and phylogenetic analyses suggest that the duplication of rhodopsin gene in Japanese eel predated the divergence of eel (Elopomorpha) and arowana (Osteoglossomorpha). Thus, based on the principle of parsimony, it is most likely that the rhodopsin paralogs were generated through a whole genome duplication in the ancestor of

  6. PEMANFAATAN LIMBAH IKAN SIDAT INDONESIA (Anguilla bicolor SEBAGAI TEPUNG PADA INDUSTRI PENGOLAHAN IKAN DI PALABUHANRATU, KABUPATEN SUKABUMI

    Directory of Open Access Journals (Sweden)

    RA Hangesti Emi Widyasari

    2014-05-01

    Full Text Available ABSTRACTThis research aims to analyze the nutritive value of flour head, liver powder and bone meal as by product of Indonesian eel (Anguilla bicolor processing. Eel waste flour was made by using a thermal process in the drum dryer fish flouring mill PT. Carmelitha Lestari in Bogor, whereas proximate analysis for chemical tests were performed in the laboratory of Integrated Chemical Laboratory, IPB and direct observation was conducted in PT Jawa Suisan Indah, Palabuhanratu Sukabumi district in October 2012—April 2013. The nutritive value based on proximate analysis showed that head flour, liver flour, and bone flour contained protein 61.78%, 53.92%, and 41.01%; fat 15.55%, 27.28%, 13.07%; carbohydrate 11.48%; 14.96%, 8.13%; water 5.44%, 8.48%, 3.01%; ash 12.95%, 3.62%, 37.49%, and crude fiber 1.33%, 0.04%, 1.11%, respectively.Keywords: Anguilla bicolor, bone flour, head flour, liver flour, nutritive valueABSTRAKPenelitian ini bertujuan untuk menganalisis kandungan gizi tepung kepala, tepung tulang dan tepung hati ikan yang merupakan limbah pengolahan ikan sidat Indonesia (Anguilla bicolor. Tepung limbah ikan sidat dibuat berdasarkan proses termal menggunakan drum dryer di pabrik penepungan ikan PT. Carmelitha Lestari di Bogor dan analisis proksimat untuk uji kimiawi dilakukan di Laboratorium Kimia Terpadu, IPB serta observasi langsung di PT Jawa Suisan Indah, Palabuhanratu Kabupaten Sukabumi pada bulan Oktober 2012—April 2013. Hasil analisis proksimat tepung kepala, tepung hati dan tepung tulang mengandung protein berturut-turut sebesar 61.78%, 53.92%, dan 41.01%; lemak sebesar 15.55%; 27.28%; 13.07%, karbohidrat sebesar 11.48%; 14.96%; 8.13%, kadar air sebesar 5.44%; 8.48%; 3.01%, kadar abu 12.95%; 3.62%; 37.49% dan serat kasar 1.33%; 0.04%; 1.11%.Kata kunci: Anguilla bicolor, nilai gizi, tepung hati, tepung kepala, tepung tulang

  7. The growth of eel fed with different protein level and protein-energy ratio

    Directory of Open Access Journals (Sweden)

    Fitria Nawir

    2015-10-01

    Full Text Available ABSTRACT The study was aimed to determine the optimum dietary protein level and energy protein ratio which can optimize growth performance of the eel A. bicolor bicolor on nursery phase.  Four treatments and three replications were applied in this study. The treatments were  P1, containing 37.66% protein with energy protein ratio 14.75 kcal GE/g (37.66%; 14.75 kcal GE/g, treatment P2 (41.30%; 13.51 kcal GE/g, treatment P3 (45.38%; 12.27 kcal GE/g, and treatment P4 (49.60%; 11.31 kcal GE/g. Eels used for this study were 6.5±0.3 g in average body weight. Eels were reared in a series of aquaria with dimension 90×40×40 cm3 and filled with 100 L of fresh water. Total weight of eel stocked in aquarium were 400 g. Eels were fed until satiated  twice a day at 8 am and 4 pm for 60 days. The result showed  that different protein level and energy protein ratio was significantly affected  growth performance (feed consumption, specific growth rate, feed efficiency, protein retention, and lipid retention, protein and fat of whole body eels at confident limit of 5%. In contrary, there was no significant different on the survival rate, hepatosomatic index, ash content, and nitrogen free extract of the body eel. The optimal growth performance was reached by dietary protein level and energy protein ratio of 45.38%; 12.27 kcal GE/g and 49.60%; 11.31 kcal GE/g. Keywords: Anguilla bicolor bicolor, energy protein ratio, feed, growth performance, protein  ABSTRAK Penelitian ini bertujuan menentukan kadar protein dan rasio energi protein optimum yang dapat meningkatkan kinerja pertumbuhan ikan sidat A. bicolor bicolor fase pendederan. Empat macam perlakuan dan tiga ulangan digunakan dalam penelitian ini. Perlakuan tersebut adalah P1 yang mengandung protein 37,66%; dengan rasio energi protein 14,75 kkal GE/g (37,66%; 14,75 kkal GE/g, perlakuan P2 (41,30%; 13,51 kkal GE/g, perlakuan P3 (45,38%; 12,27 kkal GE/g dan perlakuan P4 (49,60%; 11,31 kkal GE/g. Bobot

  8. Long-term tagging of elvers, Anguilla anguilla, with radioactive europium

    DEFF Research Database (Denmark)

    Hansen, Heinz Johs. Max; Fattah, A. T. A.

    1986-01-01

    -life of added europium of 1.6 .+-. 0.5 years. Thirteen hundred 155Eu-labelled elvers (50 Bq per eel), each weighing on average 0.21 g, were set out near Oskarshamn on the east coast of Sweden in June 1982. Three of these were caught nearby in May 1985 and one was caught in August 1985. They weighed...

  9. Induced maturation of eel weighed 100–150 gram with PMSG, antidopamine, and 17α-methyltestosterone

    Directory of Open Access Journals (Sweden)

    Nadia Mega Aryani

    2015-10-01

    Full Text Available ABSTRACT Marketed eel Anguilla bicolor bicolor is commonly produced from larvae rearing activity whose broodstocks and larvae are caught from the nature. Supply of eel broodstock is restricted by its life cycle and uncertain size variation of mature male and female. This study was aimed to evaluate the effect of hormonal induction through injection to enhance masculinization and gonadal maturation of eel at the weight of 100–150 g. The experiment used completely random design with the use of combination pregnant mare serum gonadotropin  (PMSG, antidopamine (AD, dan 17α-methyltestosterone (MT, which were (10 IU/kg PMSG + 0,01 mg/kg AD, P2 (20 IU/kg PMSG + 0,01 mg/kg AD, P3 (10 IU/kg PMSG + 0,01 mg/kg AD + 150 µg/kg MT, P4 (20 IU/kg PMSG + 0,01 mg/kg AD + 150 µg/kg MT, and P5 (control; without hormonal treatment. The result showed that an increasing of fish length along with fish weight were performed by treatment P4 and P3. The highest gonadosomatic index value was obtained by treatment P3 (1,3030±0,24262. Based on gonadal histology analysis, 2nd phase of spermatogonia development was found in P3 in week-8. The highest testosterone level was obtained by treatment P3, followed by P4, P2, and P1 in week-4. Combination of 10 IU/kg PMSG + 0,01 mg/kg AD + 150 µg/kg MT could enhance masculinization and gonadal maturation of eel in eight weeks of rearing period. Keywords: gonadal maturation, Anguilla bicolor bicolor, PMSG, AD, MT  ABSTRAK Ikan sidat Anguilla bicolor bicolor yang dipasarkan pada umumnya merupakan hasil usaha pembesaran yang benih dan induknya masih diperoleh dari alam. Penyediaan induk ikan sidat terkendala dengan siklus hidup dan variasi perbedaan ukuran induk ikan sidat jantan dan betina matang gonad yang belum pasti. Penelitian ini bertujuan untuk mengkaji peran induksi hormonal yang disuntikkan pada ikan sidat dalam mempercepat proses pematangan gonad ikan sidat ukuran 100–150 g. Metode penelitian yang digunakan adalah

  10. When will the eel recover? A full life-cycle model

    NARCIS (Netherlands)

    Astrom, M.; Dekker, W.

    2007-01-01

    The European eel population has declined over the past decades in most of its distribution area, and the stock is outside safe biological limits. The EU has taken up the challenge to design a management system that ensures the escapement of 40% of spawning-stock biomass, relative to unexploited,

  11. Morphological, anatomical and histological studies on the olfactory organs and eyes of teleost fish: Anguilla anguilla in relation to its feeding habits

    Directory of Open Access Journals (Sweden)

    K.I. Atta

    2013-05-01

    The average olfactory surface area is about 590.9% of the retinal area. Thus A. anguilla is a macrosmatic species “nose-fish” in which olfaction plays an important role in its feeding habit. It is noticed that, the photoreceptor cell layer in A. anguilla (bottom feeder is made up only of rod cells.

  12. Swimming eel-like robot

    OpenAIRE

    Vanderwegen, Gilles; Barbason, Martin

    2017-01-01

    Le mémoire "Swimming eel-like robot" consiste en la réalisation d'un robot à nage anguilliforme afin d'obtenir des résultats expérimentaux permettant de critiquer des simulations réalisées dans le cadre d'un doctorat à l'Université Catholique de Louvain. Les étapes importantes du projet sont la conception, le dimensionnement, le contrôle du robot et l'analyse cinématique et dynamique de sa nage. La phase de conception est basée sur deux critères restrictifs. Le premier est le respect du "desi...

  13. Re-evaluation of the Optimum Dietary Vitamin C Requirement in Juvenile Eel, by Using L-ascorbyl-2-monophosphate

    Directory of Open Access Journals (Sweden)

    Jun-Young Bae

    2012-01-01

    Full Text Available This study was conducted to re-evaluate the dietary vitamin C requirement in juvenile eel, Anguilla japonica by using L-ascorbyl-2-monophosphate (AMP as the vitamin C source. Five semi-purified experimental diets were formulated to contain 0 (AMP0, 30 (AMP24, 60 (AMP52, 120 (AMP108 and 1,200 (AMP1137 mg AMP kg-1 diet on a dry matter basis. Casein and defatted fish meal were used as the main protein sources in the semi-purified experimental diets. After a 4-week conditioning period, fish initially averaging 15±0.3 g (mean±SD were randomly distributed to each aquarium as triplicate groups of 20 fish each. One of five experimental diets was fed on a DM basis to fish in three randomly selected aquaria, at a rate of 3% of total body weight, twice a day. At the end of the feeding trial, weight gain (WG and specific growth rate (SGR for fish fed AMP52 and AMP108 were significantly higher than those recorded for fish fed the control diet (p<0.05. Similarly, feed efficiency (FE and protein efficiency ratio (PER for fish fed AMP52 were significantly higher than those for fish fed the control diet (p<0.05. Broken-line regression analysis on the basis of WG, SGR, FE and PER showed dietary vitamin C requirements of juvenile eel to be 41.1, 41.2, 43.9 and 43.1 (mg kg−1 diet, respectively. These results indicated that the dietary vitamin C requirement could range from 41.1 to 43.9 mg kg−1 diet in juvenile eel when L-ascorbyl-2-monophosphate was used as the dietary source of vitamin C.

  14. Taiwo et al (15)

    African Journals Online (AJOL)

    Timothy Ademakinwa

    immobilized by cervical dislocation. All samples were stored in the freezer until required for analysis. ..... Design and performance of recirculation systems for. European eel Anguilla anguilla and. African Catfish Clariasgariepinus. In: Proceeding of AES Workshop, January. 23, Orlando, Florida, USA, pp. 18–28. Eun, J. B. ...

  15. Aspergillus flavus infection on preserved Eel (Thysoidea macrurus)

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, R.; Samuel, C.T.

    The fungus Aspergillus flavus was observed growing on a 2.1 m long specimen of eel (Thyrsoidea macrurus). Half of the eel was submerged in 5% formalin in a loosely covered specimen jar. The fungus grew on the eel skin as yellowish-green, heavily...

  16. Duplicated leptin receptors in two species of eel bring new insights into the evolution of the leptin system in vertebrates

    DEFF Research Database (Denmark)

    Morini, M.; Pasquier, J.; van den Thillart, G.

    2015-01-01

    in the teleost lineage shortly after the elopomorph divergence. Quantitative PCRs revealed a wide distribution of leptins and LEPRs in the European eel, including tissues involved in metabolism and reproduction. Noticeably, leptin1 was expressed in fat tissue, while leptin2 in the liver, reflecting...

  17. TEM-EELS: A personal perspective

    Energy Technology Data Exchange (ETDEWEB)

    Egerton, R.F., E-mail: regerton@ualberta.ca [Physics Department, University of Alberta, Edmonton, Canada T6G 2E1 (Canada)

    2012-08-15

    The development of electron energy-loss spectroscopy in a transmission electron microscope (TEM-EELS) is illustrated through personal anecdote, highlighting some of the basic principles, instrumentation and personalities involved. The current state of the art is reviewed, together with some challenges for the future. -- Highlights: Black-Right-Pointing-Pointer The history of EELS instrumentation is reviewed in a lighthearted manner. Black-Right-Pointing-Pointer The current state of the art is summarized, together with some future possibilities. Black-Right-Pointing-Pointer A couple of related mathematical puzzles are offered as a challenge to the reader.

  18. Duplicated Leptin Receptors in Two Species of Eel Bring New Insights into the Evolution of the Leptin System in Vertebrates

    Science.gov (United States)

    Morini, Marina; Pasquier, Jérémy; Dirks, Ron; van den Thillart, Guido; Tomkiewicz, Jonna; Rousseau, Karine; Dufour, Sylvie; Lafont, Anne-Gaëlle

    2015-01-01

    Since its discovery in mammals as a key-hormone in reproduction and metabolism, leptin has been identified in an increasing number of tetrapods and teleosts. Tetrapods possess only one leptin gene, while most teleosts possess two leptin genes, as a result of the teleost third whole genome duplication event (3R). Leptin acts through a specific receptor (LEPR). In the European and Japanese eels, we identified two leptin genes, and for the first time in vertebrates, two LEPR genes. Synteny analyses indicated that eel LEPRa and LEPRb result from teleost 3R. LEPRb seems to have been lost in the teleost lineage shortly after the elopomorph divergence. Quantitative PCRs revealed a wide distribution of leptins and LEPRs in the European eel, including tissues involved in metabolism and reproduction. Noticeably, leptin1 was expressed in fat tissue, while leptin2 in the liver, reflecting subfunctionalization. Four-month fasting had no impact on the expression of leptins and LEPRs in control European eels. This might be related to the remarkable adaptation of silver eel metabolism to long-term fasting throughout the reproductive oceanic migration. In contrast, sexual maturation induced differential increases in the expression of leptins and LEPRs in the BPG-liver axis. Leptin2 was strikingly upregulated in the liver, the central organ of the reproductive metabolic challenge in teleosts. LEPRs were differentially regulated during sexual maturation, which may have contributed to the conservation of the duplicated LEPRs in this species. This suggests an ancient and positive role of the leptin system in the vertebrate reproductive function. This study brings new insights on the evolutionary history of the leptin system in vertebrates. Among extant vertebrates, the eel represents a unique case of duplicated leptins and leptin receptors as a result of 3R. PMID:25946034

  19. Duplicated leptin receptors in two species of eel bring new insights into the evolution of the leptin system in vertebrates.

    Directory of Open Access Journals (Sweden)

    Marina Morini

    Full Text Available Since its discovery in mammals as a key-hormone in reproduction and metabolism, leptin has been identified in an increasing number of tetrapods and teleosts. Tetrapods possess only one leptin gene, while most teleosts possess two leptin genes, as a result of the teleost third whole genome duplication event (3R. Leptin acts through a specific receptor (LEPR. In the European and Japanese eels, we identified two leptin genes, and for the first time in vertebrates, two LEPR genes. Synteny analyses indicated that eel LEPRa and LEPRb result from teleost 3R. LEPRb seems to have been lost in the teleost lineage shortly after the elopomorph divergence. Quantitative PCRs revealed a wide distribution of leptins and LEPRs in the European eel, including tissues involved in metabolism and reproduction. Noticeably, leptin1 was expressed in fat tissue, while leptin2 in the liver, reflecting subfunctionalization. Four-month fasting had no impact on the expression of leptins and LEPRs in control European eels. This might be related to the remarkable adaptation of silver eel metabolism to long-term fasting throughout the reproductive oceanic migration. In contrast, sexual maturation induced differential increases in the expression of leptins and LEPRs in the BPG-liver axis. Leptin2 was strikingly upregulated in the liver, the central organ of the reproductive metabolic challenge in teleosts. LEPRs were differentially regulated during sexual maturation, which may have contributed to the conservation of the duplicated LEPRs in this species. This suggests an ancient and positive role of the leptin system in the vertebrate reproductive function. This study brings new insights on the evolutionary history of the leptin system in vertebrates. Among extant vertebrates, the eel represents a unique case of duplicated leptins and leptin receptors as a result of 3R.

  20. EEL bio makers for water pollution monitoring. Vigilancia de la contaminacion acuatica por medio de biomarcadores en la anguila

    Energy Technology Data Exchange (ETDEWEB)

    Nunez-Delgado, A.; Fenet, H.; Casellas, C.; Stein, X.; Lafaurie, M.; Botoux, J.

    1994-01-01

    The characteristic of several bio markers capable of being use in water quality monitoring mainly those related to the cytochrome P450 enzymatic system-are reviewed, and their advantages and limitations are analyzed. The usefulness of the European eel as a bio indicator organism in environmental water pollution monitoring is studied. Experimental data support, the use of eel hepatic microsomal ethoxyresorufino-O-deethylase activity determination (EROD) as a bio marker of water pollution caused by organic compounds such as polycyclic aromatic hydrocarbons. (Author) 48 p.

  1. Efficiency of peptide nucleic acid-directed PCR clamping and its application in the investigation of natural diets of the Japanese eel leptocephali.

    Directory of Open Access Journals (Sweden)

    Takeshi Terahara

    Full Text Available Polymerase chain reaction (PCR-clamping using blocking primer and DNA-analogs, such as peptide nucleotide acid (PNA, may be used to selectively amplify target DNA for molecular diet analysis. We investigated PCR-clamping efficiency by studying PNA position and mismatch with complementary DNA by designing PNAs at five different positions on the nuclear rDNA internal transcribed spacer 1 of the Japanese eel Anguilla japonica in association with intra-specific nucleotide substitutions. All five PNAs were observed to efficiently inhibit amplification of a fully complementary DNA template. One mismatch between PNA and template DNA inhibited amplification of the template DNA, while two or more mismatches did not. DNA samples extracted from dorsal muscle and intestine of eight wild-caught leptochephalus larvae were subjected to this analysis, followed by cloning, nucleotide sequence analysis, and database homology search. Among 12 sequence types obtained from the intestine sample, six were identified as fungi. No sequence similarities were found in the database for the remaining six types, which were not related to one another. These results, in conjunction with our laboratory observations on larval feeding, suggest that eel leptocephali may not be dependent upon living plankton for their food source.

  2. Compressive Classification for TEM-EELS

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Weituo; Stevens, Andrew; Yang, Hao; Gehm, Michael; Browning, Nigel D.

    2017-07-01

    Electron energy loss spectroscopy (EELS) is typically conducted in STEM mode with a spectrometer, or in TEM mode with energy selction. These methods produce a 3D data set (x, y, energy). Some compressive sensing [1,2] and inpainting [3,4,5] approaches have been proposed for recovering a full set of spectra from compressed measurements. In many cases the final form of the spectral data is an elemental map (an image with channels corresponding to elements). This means that most of the collected data is unused or summarized. We propose a method to directly recover the elemental map with reduced dose and acquisition time. We have designed a new computational TEM sensor for compressive classification [6,7] of energy loss spectra called TEM-EELS.

  3. Toxicity of 5% rotenone to nonindigenous Asian swamp eels

    Science.gov (United States)

    Schofield, P.J.; Nico, L.G.

    2007-01-01

    Our primary goal was to determine whether rotenone would be a useful control against introduced populations of Asian swamp eels (family Synbranchidae, genus Monopterus). We report the results of a laboratory experiment comparing the efficacy of various rotenone concentrations (1, 2, 4, and 8 mg of 5% liquid rotenone/L of water) in killing nonindigenous swamp eels of various sizes (1-350 g) from the three known Florida populations. Although most small swamp eels were killed at concentrations of 2 and 4 mg/L. 100% mortality of adult swamp eels was achieved only at 8 mg/L. We conclude that the effective use of rotenone to control established Florida swamp eel populations would be difficult, based on the relatively high concentration of rotenone needed to kill swamp eels; the complexity of the swamp eel's habitat; and our observations of the species' habitat use and behavior, including its widespread distribution and life history characteristics (e.g., burrowing and overland movement) that enhance its invasion and survival in multiple environments. Nevertheless, control of swamp eels may be achieved in certain situations. A combination of rotenone and electroshocking may be an effective way to eradicate swamp eels from small water bodies and to control populations in larger habitats. However, we are cautious in this recommendation and provide details related to the technical aspects of this type of strategy and caveats related to the toxicity of the chemical.

  4. Transition radiation in EELS and cathodoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Stöger-Pollach, Michael, E-mail: stoeger@ustem.tuwien.ac.at; Kachtík, Lukáš; Miesenberger, Bernhard; Retzl, Philipp

    2017-02-15

    The excitation probability of transition radiation is measured for varying beam energies in a transmission electron microscope once using optical spectrometry of the emitted light and second using electron energy loss spectrometry. In both cases similar results are found being in good agreement with theory. The knowledge about this probability enables us to judge whether or not transition radiation has to be considered in EELS and CL data interpretation. Additionally it is shown that the emission of transition radiation happens at the sample surfaces only, when the electron passes the vacuum/sample interface and thus feeling the change of its dielectric environment. We demonstrate that in the case of aluminum the influence of transition radiation on the low loss EELS spectrum is only minor and conclude that it might be negligible for many other materials. - Highlights: • We determine the probability for the excitation of transition radiation at a large variety of beam energies in TEM. • We use a GATAN VULCAN system for optical spectrometry in the TEM. • We do angular resolved EELS experiments in a standard TEM with an angular resolution of 7.57 μrad.

  5. Eelness: Transcriptomic analysis of Vibrio-induced immune response in European eel

    OpenAIRE

    Callol Junyer, Agnès

    2014-01-01

    La malaltia és l’alteració de l’estat fisiològic d’un individu, dificultant les seves funcions vitals i fins i tot, comportant a la mort. Tots els éssers vius poden contraure malaltia, aquesta, és majoritàriament provocada per microorganismes patògens, incloent bacteris, virus, protozous i fongs. Al llarg de la infecció, la relació hoste-patògen és clau. Per una banda, l’hoste ha de comptar amb un sistema immunitari eficaç, capaç de combatre l’infecció, mantenint les funcions vitals i per t...

  6. Characterization of the binding specificity of Anguilla anguilla agglutinin (AAA) in comparison to Ulex europaeus agglutinin I (UEA-I).

    Science.gov (United States)

    Baldus, S E; Thiele, J; Park, Y O; Hanisch, F G; Bara, J; Fischer, R

    1996-08-01

    Using immunochemical and immunohistochemical methods, the binding site of Anguilla anguilla agglutinin (AAA) was characterized and compared with the related fucose-specific lectin from Ulex europaeus (UEA-I). In solid-phase enzyme-linked immunoassays, the two lectins recognized Fuc alpha 1-2Gal beta-HSA. AAA additionally cross-reacted with neoglycolipids bearing lacto-N-fucopentaose (LNFP) I [H type 1] and II [Le(a)] and lactodifucotetraose (LDFT) as glycan moieties. UEA-I, on the other hand, bound to a LDFT-derived neoglycolipid but not to the other neoglycolipids tested. Binding of AAA to gastric mucin was competitively neutralized by Le(a)-specific monoclonal antibodies. UEA-I binding, on the other hand, was reduced after co-incubation with H type 2- and Le(y)-specific monoclonal antibodies. According to our results, AAA reacts with fucosylated type 1 chain antigens, whereas UEA-I binds only to the alpha 1-2-fucosylated LDFT-derived neoglycolipid. In immunohistochemical studies, the reactivity of AAA and UEA-I in normal pyloric mucosa from individuals with known Lewis and secretor status was analysed. AAA showed a broad reaction in the superficial pyloric mucosa from secretors and non-secretors, but AAA reactivity was more pronounced in Le(a+b-) individuals. On the other hand, UEA-I stained the superficial pyloric mucosa only from secretor individuals. A staining of deep mucous glands by the lectins was found in all specimens. Both reacted with most human carcinomas of different origin. Slight differences in their binding pattern were observed and may be explained by the different fine-specificities of the lectins.

  7. 33 CFR 117.598 - Eel Pond Channel.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Eel Pond Channel. 117.598 Section 117.598 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.598 Eel Pond Channel. The...

  8. Spatial habitat for eel larva at Cimandiri estuary, West Java

    Science.gov (United States)

    Takarina, N. D.; Supriatna

    2017-07-01

    The estuarine ecosystem is known as suitable breeding sites for fishes because this particular habitat is receiving continuous organic matters from river ways and constant sunlight due to its depth that allows sunlight penetration. Cimandiri estuary is one of the estuaries located in the south of Java Island close to the Indian Ocean and known as a suitable habitat for eel larva that routinely collected by local people. Eel habitat has a relationship with the dynamic of space. This dynamic influenced by season, water flow, tide, bathymetry, salinity and dissolved oxygen (DO). The geographic information system is an approach in studying habitat dynamic, through modeling. Furthermore, the spatial model for eel larva habitat is required for land use planning that aimed to achieve sustainable eels larva rearing and conserve estuarine habitat as well. The aim of this research was to investigate dynamics on spatial habitat of eel larva at Cimandiri estuary, West Java.

  9. Functional characterisation of eel dopamine D2 receptors and involvement in the direct inhibition of pituitary gonadotrophins

    DEFF Research Database (Denmark)

    Jolly, C.; Rousseau, K.; Prézeau, L.

    2016-01-01

    pharmacologically related to the D2 family. In the European eel, two distinct D2 receptor (D2‐R) paralogous genes have been identified (D2A‐R and D2B‐R) and both were shown to be expressed in the pituitary. We investigated the potential role of each paralogue in the control of gonadotroph function in this species....... Eel recombinant D2A‐R or D2B‐R were expressed in HEK 293 cells, with a universal Gα subunit, and receptor activation was followed by inositol phosphate production. Recombinant D2‐Rs exhibited a comparable affinity for DA, although they had differential affinities for mammalian D2‐R agonists...... and antagonists, supporting subtle structure/activity differences. Furthermore, using eel pituitary cell primary cultures, the expression by gonadotroph cells of both native eel D2‐R paralogues was examined by in situ hybridisation of D2A‐R or D2B‐R transcripts, coupled with immunofluorescence of luteinising...

  10. Three nuclear and two membrane estrogen receptors in basal teleosts, Anguilla sp.: Identification, evolutionary history and differential expression regulation

    DEFF Research Database (Denmark)

    Lafont, Anne Gaëlle; Rousseau, Karine; Tomkiewicz, Jonna

    2016-01-01

    expressed in the eel, but with differential patterns of tissue expression and regulation. ESR1 only is consistently up-regulated in vivo in female eel BPG-liver axis during induced sexual maturation, and also up-regulated in vitro by estradiol in eel hepatocyte primary cultures. This first comparative study...

  11. Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (South Atlantic): American Eel,

    Science.gov (United States)

    1984-07-01

    freshwater (see the maturation is more rapid in popula- GROWTH CHARACTERISTICS section for , . S tions along the South Atlantic Bight. aging methods ). 4...1.1 mm (Tesch that eels may use geoelectric fields 1977). Incubation periods of American generated by ocean currents to navi- eel eggs are not known...common Robins, C. R., D. M. Cohen, and C. H. methods in eel assessment. Rapp. Robins. 1979. The eels, Anquilla P.-V. Reun. Cons. Int. Explor. and

  12. Vibrio vulnificus outbreaks in Dutch eel farms since 1996: strain diversity and impact.

    NARCIS (Netherlands)

    Haenen, O.L.M.; Zanten, van E.; Jansen, R.; Roozenburg, I.; Engelsma, M.Y.; Dijkstra, A.; Boers, S.A.; Voorbergen-Laarman, M.; Möller, A.V.M.

    2014-01-01

    Vibrio vulnificus is a potentially zoonotic bacterial pathogen of fish, which can infect humans (causing necrotic fasciitis). We analysed 24 V. vulnificus isolates (from 23 severe eel disease outbreaks in 8 Dutch eel farms during 1996 to 2009, and 1 clinical strain from an eel farmer) for genetic

  13. Application of AES and EELS for surface/interface characterization

    Energy Technology Data Exchange (ETDEWEB)

    Plusnin, N.I. E-mail: plusnin@iacp.dvo.ru

    2004-07-01

    In the work a review of results on the surface/interface characterization in the Cr, Co and Si adsorbat--Si, CrSi{sub 2} substrate system is presented where additional possibilities for applications of AES and EELS have been developed. Peak intensity dependence versus the probing depth or the primary beam energy gives information about the thickness (AES, EELS) and the lattice interplane distance (EELS) of a surface layer. Energy position of plasma satellite peak for AES peak of substrate shows electron plasma concentration of an interface under the surface layer. Relative value of the substrate AES peak attenuation allows identify average position of atoms on its single-crystal surface.

  14. Regional Variations in the Risk and Severity of Ciguatera Caused by Eating Moray Eels

    Directory of Open Access Journals (Sweden)

    Thomas Y. K. Chan

    2017-06-01

    Full Text Available Moray eels (Gymnothorax species from tropical waters have long been known to be high-risk species, and the consumption of particularly the viscera or ungutted eels can result in severe ciguatera (known as Gymnothorax or moray eel poisoning, characterized by prominent neurological features. In this review, the main objective was to describe the risk and severity of ciguatera caused by eating moray eels in different parts of the world. Moray eels can accumulate very high ciguatoxin (CTX levels in the flesh and particularly the liver. Therefore, even the smaller ones can be toxic and the consumption of an average portion (particularly liver can result in severe or fatal ciguatera. Moray eels (particularly when ungutted must never be served in gatherings since they can cause mass poisoning because of their large sizes and high CTX levels. Apart from regulatory measures restricting or excluding access, the public should be repeatedly warned to avoid eating moray eels.

  15. Differential timing of gene expression regulation between leptocephali of North Atlantic eels in the Sargasso Sea

    DEFF Research Database (Denmark)

    Bernatchez, Louis; Saint-Cyr, Jérôme; Maes, Gregory E.

    2011-01-01

    the alternative hypotheses of (1) differential timing of gene expression regulation during early development versus (2) species-specific differences in expression of particular genes. Our results provide much stronger support for the former hypothesis since no gene showed consistent significant differences...... in expression levels between the two species. In contrast, 146 genes showed differential timings of expression between species, although the observed expression level differences between the species were generally small. Consequently, species-specific gene expression regulation seems to play a minor role...... in species differentiation. Overall, these results show that the basis of the early developmental divergence between the American and European eel is probably influenced by differences in the timing of gene expression regulation for genes involved in a large array of biological functions...

  16. The first record of Paratenuisentis ambiguus (Acanthocephala, Tenuisentidae in Poland

    Directory of Open Access Journals (Sweden)

    Jolanta Morozińska-Gogol

    2008-06-01

    Full Text Available Paratenuisentis ambiguus, an acanthocephalan originating from North America,is an alien species parasitising the European eel Anguilla anguilla. It was first recorded in Lake Lebsko,on the central coast of Poland. The report gives morphometric measurements of male and female P. ambiguus from this locality. Because of the spread of the intermediate host Gammarus tigrinus andthe appearance of new adults in eels along the southern Baltic Coast, P. ambiguus is evidently able to complete its life cycle in Baltic coastal waters.

  17. Performance and optimisation of trickling filters on eel farms

    NARCIS (Netherlands)

    Kamstra, A.; Heul, van der J.W.; Nijhof, M.

    1998-01-01

    The design of trickling filters used on commercial eel farms differs considerably with respect to dimensions, hydraulic and substrate loads and filter medium applied. In this paper, a model, developed for ammonium removal in a pilot-scale trickling filter, has been validated for a range of

  18. Tracking anguillid eels: five decades of telemetry-based research

    DEFF Research Database (Denmark)

    Beguer-Pon, Melanie; Dodson, Julian J.; Castonguay, Martin

    2018-01-01

    to investigate the migratory behaviour of maturing eels as they leave fresh water to reach the sea. Among recent findings is the observation that downstream migration in continental waters is quite discontinuous, characterised by extended stopovers. Reconstructed migration routes in the open ocean obtained from...

  19. Behavioural response of silver eel to effluent plumes: Telemetry experiments

    NARCIS (Netherlands)

    Winter, H.V.; Keeken, van O.A.; Foekema, E.M.; Kleissen, F.; Friocourt, Y.; Beare, D.J.

    2011-01-01

    Fish migration may be hampered by a range of physical barriers. That non-physical barriers such as sudden changes in water quality may also serve as barriers is often stated, but only very few studies address this issue. This study focusses on linking the behavioural response of silver eel and river

  20. EEL spectroscopic tomography: Towards a new dimension in nanomaterials analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yedra, Lluis, E-mail: llyedra@el.ub.es [Laboratory of Electron Nanoscopies (LENS)-MIND/IN2UB, Dept. d' Electronica, Universitat de Barcelona, c/ Marti Franques 1, E-08028 Barcelona (Spain); CCiT, Scientific and Technological Centers, Universitat de Barcelona, C/Lluis Sole i Sabaris 1, E-08028 Barcelona (Spain); Eljarrat, Alberto [Laboratory of Electron Nanoscopies (LENS)-MIND/IN2UB, Dept. d' Electronica, Universitat de Barcelona, c/ Marti Franques 1, E-08028 Barcelona (Spain); Arenal, Raul [Laboratorio de Microscopias Avanzadas (LMA), Instituto de Nanociencia de Aragon (INA), Universidad de Zaragoza, E-50018 Zaragoza (Spain); Fundacion ARAID, E-50004 Zaragoza (Spain); Pellicer, Eva; Cabo, Moises [Departament de Fisica, Facultat de Ciencies, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Lopez-Ortega, Alberto; Estrader, Marta [CIN2(CIN-CSIC) and Universitat Autonoma de Barcelona, Catalan Institute of Nanotechnology, Campus de la UAB, E-08193 Bellaterra (Spain); Sort, Jordi [Institucio Catalana de Recerca i Estudis Avancats (ICREA), Departament de Fisica, Facultat de Ciencies, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Baro, Maria Dolors [Departament de Fisica, Facultat de Ciencies, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); and others

    2012-11-15

    Electron tomography is a widely spread technique for recovering the three dimensional (3D) shape of nanostructured materials. Using a spectroscopic signal to achieve a reconstruction adds a fourth chemical dimension to the 3D structure. Up to date, energy filtering of the images in the transmission electron microscope (EFTEM) is the usual spectroscopic method even if most of the information in the spectrum is lost. Unlike EFTEM tomography, the use of electron energy-loss spectroscopy (EELS) spectrum images (SI) for tomographic reconstruction retains all chemical information, and the possibilities of this new approach still remain to be fully exploited. In this article we prove the feasibility of EEL spectroscopic tomography at low voltages (80 kV) and short acquisition times from data acquired using an aberration corrected instrument and data treatment by Multivariate Analysis (MVA), applied to Fe{sub x}Co{sub (3-x)}O{sub 4}@Co{sub 3}O{sub 4} mesoporous materials. This approach provides a new scope into materials; the recovery of full EELS signal in 3D. -- Highlights: Black-Right-Pointing-Pointer EELS-SI tomography was performed at low voltage and low acquisition times. Black-Right-Pointing-Pointer MVA has been applied for noise reduction and information extraction. Black-Right-Pointing-Pointer Tomographic reconstruction has been achieved for chemical information. Black-Right-Pointing-Pointer Elemental distribution extraction in 3D has been proved.

  1. Quantitative comparisons of maternal transcripts related to cell division between good and poor quality eggs from artificially matured Japanese eel Anguilla japonica

    National Research Council Canada - National Science Library

    泉, ひかり; 玄, 浩一郎; 堀内, 萌未; 松谷, 紀明; 井尻, 成保; 足立, 伸次

    2016-01-01

    ニホンウナギ人為催熟では常に良質卵が得られるとは限らず,また,卵質悪化の分子機構もわかっていない。そこで本研究では,人為催熟ニホンウナギの不良卵の分子生物学的特徴を明らかにするため,細胞分裂関連遺伝子の母性 mRNA...

  2. Acute toxicity of two lampricides, 3-trifluoromethyl-4-nitrophenol (TFM) and a TFM: 1% niclosamide mixture, to sea lamprey, three species of unionids, haliplid water beetles, and American eel

    Science.gov (United States)

    Boogaard, Michael A.; Rivera, Jane E.

    2011-01-01

    We conducted a series of toxicological treatments with 3-trifluoromethyl-4-nitrophenol (TFM) and a TFM:1% 2′,5-dichloro-4′-nitrosalicylanilide (niclosamide) mixture, two compounds used to control larval sea lamprey (Petromyzon marinus) in Great Lakes tributaries, to evaluate the acute toxicity of the lampricides to a number of nontarget species of concern. Treatments were conducted with yellow stage American eel (Anguilla rostrata), adult and larval haliplid water beetles (Haliplus spp.), a surrogate for the endangered Hungerford’s crawling water beetle (Brychius hungerfordi), and adults of three unionid species—giant floater (Pyganadon grandis), fragile papershell (Leptodea fragilis), and pink heelsplitter (Potamilus alatus). Treatments were conducted using a serial dilution system consisting of nine test concentrations and an untreated control with 20% dilution between concentrations. Narcosis was evident among giant floaters exposed to the TFM and the TFM:1% niclosamide mixture and among pink heelsplitters exposed to the TFM:1% niclosamide mixture only but mostly at concentrations greater than 2-fold that required to kill 100% of larval sea lamprey (minimum lethal concentration (MLC)). Tests with the haliplid beetle suggest the risks to the Hungerford’s crawling water beetle associated with TFM applications are minimal. Concentrations over 2-fold the sea lamprey MLC did not kill adult or larval water beetles. Preliminary behavioral observations suggest water beetles may avoid treatment by crawling out of the water. Adult water beetles exposed to TFM at 3-fold the sea lamprey MLC were observed above the water line more often than controls. The lampricide TFM was not acutely toxic to American eel. Mortalities were rare among American eel exposed to TFM concentrations up to 7-fold the observed sea lamprey MLC. Similarly, for the TFM:1% niclosamide mixture, mortalities were rare among American eel exposed to nearly 5-fold the observed sea lamprey MLC

  3. An Optimized Biological Taser: Electric Eels Remotely Induce or Arrest Movement in Nearby Prey.

    Science.gov (United States)

    Catania, Kenneth C

    2015-09-01

    Despite centuries of interest in electric eels, few studies have investigated the mechanism of the eel's attack. Here, I review and extend recent findings that show eel electric high-voltage discharges activate prey motor neuron efferents. This mechanism allows electric eels to remotely control their targets using two different strategies. When nearby prey have been detected, eels emit a high-voltage volley that causes whole-body tetanus in the target, freezing all voluntary movement and allowing the eel to capture the prey with a suction feeding strike. When hunting for cryptic prey, eels emit doublets and triplets, inducing whole-body twitch in prey, which in turn elicits an immediate eel attack with a full volley and suction feeding strike. Thus, by using their modified muscles (electrocytes) as amplifiers of their own motor efferents, eel's motor neurons remotely activate prey motor neurons to cause movement (twitch and escape) or immobilization (tetanus) facilitating prey detection and capture, respectively. These results explain reports that human movement is 'frozen' by eel discharges and shows the mechanism to resemble a law-enforcement Taser. © 2015 The Author(s) Published by S. Karger AG, Basel.

  4. Molecular nutritional characteristics of vinasse pike eel (Muraenesox cinereus) during pickling.

    Science.gov (United States)

    Chen, Daian; Ye, Yangfang; Chen, Juanjuan; Zhan, Pingping; Lou, Yongjiang

    2017-06-01

    Vinasse pike eel (Muraenesox cinereus) is a traditional Chinese food with a characteristic flavour, taste, and nutritional composition. Its flavour is closely related to the molecular nutritional composition of this food pickled product. In this study, we characterised the changes in the nutritional composition of pike eel during vinasse pickling. Nuclear magnetic resonance spectroscopy revealed 33 components in eel, e.g. a range of organic acids, amino acids, alcohols, and sugars. Multivariate data analysis further revealed that the nutritional composition of eel undergoes major changes during pickling, which were highlighted by the consumption of sucrose and creatine, the accumulation of a range of organic acids, alcohols, glucose, and creatinine, as well as in the fluctuation of some amino acids. The abundant sucrose, glutamate, creatine, and lactate could take an active part in the flavour formation of vinasse eel. This work provides insight into the nutritional characteristics of vinasse eel during pickling. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Gentle STEM: ADF imaging and EELS at low primary energies

    Energy Technology Data Exchange (ETDEWEB)

    Krivanek, Ondrej L., E-mail: krivanek@nion.com [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States); Dellby, Niklas; Murfitt, Matthew F. [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States); Chisholm, Matthew F.; Pennycook, Timothy J. [Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN 37831-6069 (United States); Suenaga, Kazutomo [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565 (Japan); Nicolosi, Valeria [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)

    2010-07-15

    Aberration correction of the scanning transmission electron microscope (STEM) has made it possible to reach probe sizes close to 1 A at 60 keV, an operating energy that avoids direct knock-on damage in materials consisting of light atoms such as B, C, N and O. Although greatly reduced, some radiation damage is still present at this energy, and this limits the maximum usable electron dose. Elemental analysis by electron energy loss spectroscopy (EELS) is then usefully supplemented by annular dark field (ADF) imaging, for which the signal is larger. Because of its strong Z dependence, ADF allows the chemical identification of individual atoms, both heavy and light, and it can also record the atomic motion of individual heavy atoms in considerable detail. We illustrate these points by ADF images and EELS of nanotubes containing nanopods filled with single atoms of Er, and by ADF images of graphene with impurity atoms.

  6. Flood Deposition Analysis of Northern California's Eel River (Flood- DANCER)

    Science.gov (United States)

    Ahlgren, S.; Bauman, P. D.; Dillon, R. J.; Gallagher, N.; Jamison, M. E.; King, A.; Lee, J.; Siwicke, K. A.; Harris, C. K.; Wheatcroft, R. A.; Borgeld, J. C.; Goldthwait, S. A.

    2006-12-01

    Characterizing and quantifying the fate of river born sediment is critical to our understanding of sediment supply and erosion in impacted coastal areas. Strata deposited in coastal zones provide an invaluable record of recent and historical environmental events. The Eel River in northern California has one of the highest sediment yields of any North American river and has preserved evidence of the impact of recent flood events. Previous research has documented sediment deposits associated with Eel River flood events in January 1995, March 1995, and January 1997. These deposits were found north of the river mouth on the mid shelf in water depths from 50-100 m. Sediment strata were up to 5-10 cm thick and were composed of fine to very fine grained silts and clays. Until recently, no model had been able to correctly reproduce the sediment deposits associated with these floods. In 2005, Harris et al. developed a model that accurately represents the volume and location of the flood deposit associated with the January 1997 event. However, rigorous assessment of the predictive capability of this model requires that a new flood of the Eel River be used as a test case. During the winter of 2005-06 the Eel River rose above flood stage reaching discharge similar to the flood of January 1995 which resulted in flood sedimentation on the Eel River shelf. A flood-related deposit 1-5 cm thick was found in water depths of 60-90 m approximately 20-35 km north of the river mouth. Flood deposits were recognized in box cores collected in the months following the flood. As in previously studied events, flood- related strata near the sediment surface were recognized in core x-radiographs, resistivity and porosity profiles, and were composed of fine to very fine grained silts and clays. In addition, surface flood sediments were associated with lower concentrations of benthic foraminifera compared with deeper sediments. The January 2006 flood deposit was similar in thickness to the

  7. Characterization of organochlorine pesticides, brominated flame retardants and dioxin-like compounds in shellfish and eel from Fiji.

    Science.gov (United States)

    Lal, Vincent; Bridgen, Phil; Votadroka, Waisea; Raju, Rupantri; Aalbersberg, William

    2014-09-01

    This article gives an overview of a range of persistent organic pollutant chemical levels in shellfish (Batissa violacea and Anadara antiquata) species and eel (Gymnothorax flavimarginatus) from Fiji. As there is limited data in published literature to date, this paper reports first data on a range of persistent organic pollutants and highlights the more prominent POP chemicals present in marine biota in Fiji. A significant number of POP chemicals were detected (e.g. 17 PCDD/PCDF, 12dl-PCBs, organochlorine pesticides and brominated flame retardants), the concentrations found were generally low (e.g. parts per billion level). The low levels of contamination are indicative of a low input from long range and short-range transport as well as few local point sources. Also concentrations of POPs in eel and shellfish from Fiji are low in comparison to wild species in other regions and are within acceptable limits for POP chemicals in fish and fishery products set by the European Union. It describes also results of early studies on basic POPs levels in shellfish in several Pacific Island Countries, which generally show relatively low levels. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Eel, cod and seatrout harvest in Danish recreational fishing during 2011

    DEFF Research Database (Denmark)

    Sparrevohn, Claus Reedtz; Storr-Paulsen, Marie

    , it was estimated that 80 t [Relative standard error (RSE)=6%] eel, close to 1,300 t (RSE=5 %) cod and 400 t (RSE=5 %) seatrout (including freshwater catches) was harvested in the recreational fishery. Eel is almost exclusively taken in the passive gear fykenet fishery and seatrout was mainly caught by anglers...

  9. Ophichthid eels in the coelom of several Natal offshore reef fish ...

    African Journals Online (AJOL)

    Mummified ophichthid eels are reported from the coeloms of several Natal continental shelf reef fish species. Originally mistaken to be parasitic, these eels are in fact free-living and are eaten by fish. Once ingested, they bore their way out of the stomach, using their pointed tails and become encapsulated in connective ...

  10. Indole-positive Vibrio vulnificus isolated from disease outbreaks on a Danish eel farm

    DEFF Research Database (Denmark)

    Dalsgaard, Inger; Høi, L.; Siebeling, R.J.

    1999-01-01

    Vibrio vulnificus was isolated in 1996 from 2 disease outbreaks on a Danish eel farm which used brackish water. A characteristic clinical sign was extensive, deep muscle necrosis in the head region. V. vulnificus was isolated from kidney, mucus, spleen, gill and intestine of diseased eels. Thirty...

  11. RECRUTEMENT DES CIVELLES (ANGUILLA ANGUILLA SUR LA COTE MEDITERRANEENNE FRANÇAISE : ANALYSE COMPAREE DES CARACTERISTIQUES BIOMETRIQUES ET PIGMENTAIRES DES SAISONS 1974-75 ET 2000-01.

    Directory of Open Access Journals (Sweden)

    LEFEBVRE F.

    2003-07-01

    Full Text Available Une campagne d’échantillonnage des civelles Anguilla anguilla a été menée de novembre 2000 à mai 2001 au grau de la Fourcade (Saintes-Maries-de-la-Mer, côte méditerranéenne française. Des civelles ont été capturées sur toute la période d’échantillonnage, mais les maxima d’abondance se situent en janvier-février et, dans une moindre mesure, en avril. Afin d’optimiser le recrutement dans les lagunes littorales intérieures, la mesure de gestion proposée est donc de favoriser l’ouverture des martelières au milieu de l’hiver. Le suivi des proportions mensuelles des différents stades pigmentaires (de V A à VI A4 permet de conclure à un vieillissement généralisé des civelles en recrutement de novembre à mars, puis à l’arrivée d’un deuxième flux de civelles jeunes en avril. Parallèlement, il est observé une diminution très nette des masses et des longueurs moyennes mensuelles, et ce, même en ne considérant qu’un stade pigmentaire donné (en l’occurrence V B. Ces résultats sur l’évolution des caractéristiques biométriques et pigmentaires sont en accord avec les deux séries de travaux déjà menés sur la façade méditerranéenne française (années 30 et 70, ainsi qu’avec les données publiées en différents points de la façade atlantique. L’analyse comparée de ces données avec celles issues de la dernière étude en date sur la côte méditerranéenne française (Bages-Sigean, Languedoc-Roussillon, campagne 1974-75 ; LECOMTE-FINIGER, 1976 montre une composition pigmentaire mensuelle totalement différente, et révèle une diminution significative de la longueur des civelles, de l’ordre de 5 % en 25 ans.

  12. Mapping Chemical Bonds in Semiconductor Devices by Monitoring the Shifts of EELS Edges.

    Science.gov (United States)

    Potapov, Pavel; Svistunova, Elena L; Gulyaev, Alexander A

    2017-10-01

    Scanning transmission electron microscopy (STEM) in combination with electron energy-loss spectroscopy (EELS) can deliver information about variations of bonding at the nm scale. This is typically performed by analyzing the electron-loss near edge structure (ELNES) of given EELS edges. The present paper demonstrates an alternative way of a bonding examination through monitoring the EELS onset positions. Two conditions are essential for their accurate measurement. One (hardware) is using the dual EELS instrumentation that provides near simultaneous acquisition of low-loss and core-loss spectra. Another (software) is the least-square fitting of observed spectra to a reference spectrum. The combination of these hardware and software techniques reveals the positions of EELS onsets with the precision sufficient for mapping tiny variations of bonding. The paper shows that the method is capable of helping to solve practical tasks of nanoscale engineering like the analysis of modern CMOS devices.

  13. Oceanic migration behaviour of tropical Pacific eels from Vanuatu

    DEFF Research Database (Denmark)

    Schabetsberger, R; Økland, F; Aarestrup, K

    2013-01-01

    ), 39 A. megastoma (50 to 131 cm), and 3 A. obscura (119 to 126 cm) were caught. Seven individuals were tagged with pop-up satellite transmitters and released offshore. One A. marmorata migrated 843 km towards the South Equatorial Current. The tag surfaced only 330 km from the point where the smallest...... leptocephalus has been captured so far. Tags on A. megastoma and A. obscura popped up within the archipelago. All 3 species exhibited pronounced diel vertical migrations. Eels descended from around 200 m nighttime depth, to 320 (A. obscura), 650 (A. marmorata), and 750 m (A. megastoma) during the day. A clear...

  14. Behavioural response of silver eel to effluent plumes: Telemetry experiments

    OpenAIRE

    Winter, H.V.; Keeken, van, O.A.; Foekema, E.M.; Kleissen, F.; Friocourt, Y.; Beare, D.J.

    2011-01-01

    Fish migration may be hampered by a range of physical barriers. That non-physical barriers such as sudden changes in water quality may also serve as barriers is often stated, but only very few studies address this issue. This study focusses on linking the behavioural response of silver eel and river lamprey when encountering a waste water plume (effluent) in field situations. Individual fish movements were tracked by means of acoustic telemetry in 2D (in 2009) and in 3D (in 2010) at a locatio...

  15. Metal Accumulations in Water, Sediment, Crab (Callinectes sapidus) and Two Fish Species (Mugil cephalus and Anguilla anguilla) from the Köyceğiz Lagoon System-Turkey: An Index Analysis Approach.

    Science.gov (United States)

    Genç, Tuncer Okan; Yilmaz, Fevzi

    2017-08-01

    The concentrations of six metals (Hg, Cd, Cu, Pb, Cr and Zn) individual total metal load (IMBI) values and its relation to condition index were determined in water, sediment and tissues of crab (Callinectes sapidus) and two fish species (Mugil cephalus and Anguilla anguilla) inhabiting Köyceğiz Lagoon System. The average distribution of the IMBI values ranged from 0.033 to 0.265. Distribution patterns of IMBI in species follow the sequence: A. anguilla > M. cephalus > C. sapidus. Results showed that there are positive relationships between species sizes and metal levels in most cases. The concentrations of Pb in muscle in the three studied species were in all cases considerably higher than the maximum levels set by law. Average Cd, Cu and Zn values in M. cephalus were also higher than the limits proposed for fish by FAO/WHO, EC and TFC. Therefore, the human consumption of all analysed species is not recommended.

  16. Applications of STEM-EELS to complex oxides

    KAUST Repository

    Gázquez, Jaume

    2016-06-26

    In this chapter we will review a few examples of applications of atomic resolution aberration corrected scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS) to complex oxide materials. These are most challenging systems where subtle changes in structure or chemistry may result in colossal responses in macroscopic physical behavior. Here, we will review how atomic resolution compositional mapping can be achieved in manganite thin films and single crystals, highlighting the importance of considering artifacts during quantification. Besides, minor changes in near edge fine structure may take place when the crystalline environment, and hence nearest neighbor configuration, is modified. These can also be tracked by atomic resolution EELS, as will be shown through the study of binary Fe oxides. Also, examples regarding the study of distributions of point defects such as O vacancies in cobaltite thin films will be discussed. In these materials, a combination of epitaxial strain and defects may promote physical behaviors not present in bulk, such as the stabilization of unexpected spin state superlattices. Last, a study of extended defects such as dislocation lines will be reviewed. In particular, we will show how chemical segregation at dislocation cores in yttria-stabilized zirconia grain boundaries results in the generation of static O vacancies that affect the local electrostatic potential and hence, the macroscopic ionic conduction properties. © 2016.

  17. Preservation and Alteration of the 1995 Eel River Flood Deposit

    Science.gov (United States)

    Richey, C. A.; Bodenhamer, C.; Borgeld, J. C.; Brower, J.; Genger, H. M.; Hayduk, L. A.; Ryan, T. W.; Slimmer, M. D.; Westman, V.

    2004-12-01

    The Eel River shelf of northern California is episodically subject to seasonal flood events and associated sediment deposition. Flooding of the Eel River in the winter and spring of 1995, and the winter of 1997, resulted in a recognizable sequence of layers deposited across much of the adjacent continental shelf. Event-response sampling allowed the short term fate of the deposits to be documented (Wheatcroft, 2000). Within a few years after the 1997 event, the flood deposit was mixed or remobilized such that the original deposit was not recognized in core x-radiographs anywhere on the shelf. However, remnants of the 1995 flood deposit were still identifiable as of October 2001 (Wheatcroft et al., in progress). In May 2004, a total of 31 box cores were collected at 23 different stations along transects established by previous studies. Flood layers were still present and recognizable in x-radiographs at several stations. Many of the layers identified in x-radiographs were, although preserved, visibly disrupted. In locations where x-radiographs were inconclusive, the unusually fine-grained nature of the deposit allowed them to be detected using standard sediment size analyses. The mean percent of sediment worms were identified as the dominant taxonomic group, constituting approximately 80% of the identified organisms, which is consistent with previous research (Wheatcroft et al., in progress; Bentley and Nittrouer, 2003). The dominance of polychaetes is notable in light of the fact that these subsurface deposit feeders are likely to mix sediment to substantial depths (Wheatcroft et al., in progress). Despite this biological activity, the flood layer is still recognizable a decade after the initial event. As a result, the 1995 flood deposit may ultimately become a permanent piece of the stratigraphic record.

  18. Electric Eels Concentrate Their Electric Field to Induce Involuntary Fatigue in Struggling Prey.

    Science.gov (United States)

    Catania, Kenneth C

    2015-11-16

    Nature is replete with predator venoms that immobilize prey by targeting ion channels. Electric eels (Electrophorus electricus) take a different tactic to accomplish the same end. Striking eels emit electricity in volleys of 1 ms, high-voltage pulses. Each pulse is capable of activating prey motor neuron efferents, and hence muscles. In a typical attack, eel discharges cause brief, immobilizing tetanus, allowing eels to swallow small prey almost immediately. Here I show that when eels struggle with large prey or fish held precariously, they commonly curl to bring their own tail to the opposite side of prey, sandwiching it between the two poles of their powerful electric organ. They then deliver volleys of high-voltage pulses. Shortly thereafter, eels juggle prey into a favorable position for swallowing. Recordings from electrodes placed within prey items show that this curling behavior at least doubles the field strength within shocked prey, most likely ensuring reliable activation of the majority of prey motor neurons. Simulated pulse trains, or pulses from an eel-triggered stimulator, applied to a prey muscle preparations result in profound muscle fatigue and loss of contractile force. Consistent with this result, video recordings show that formerly struggling prey are temporarily immobile after this form of attack, allowing the manipulation of prey that might otherwise escape. These results reveal a unique use of electric organs to a unique end; eels superimpose electric fields from two poles, ensuring maximal remote activation of prey efferents that blocks subsequent prey movement by inducing involuntary muscle fatigue. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Transmission to Eels, Portals of Entry, and Putative Reservoirs of Vibrio vulnificus Serovar E (Biotype 2)

    OpenAIRE

    Marco-Noales, Ester; Milán, Miguel; Fouz, Belén; Sanjuán, Eva; Amaro, Carmen

    2001-01-01

    Vibrio vulnificus serovar E (formerly biotype 2) is the etiologic agent that is responsible for the main infectious disease affecting farmed eels. Although the pathogen can theoretically use water as a vehicle for disease transmission, it has not been isolated from tank water during epizootics to date. In this work, the mode of transmission of the disease to healthy eels, the portals of entry of the pathogen into fish, and their putative reservoirs have been investigated by means of laborator...

  20. Isolation of heat-tolerant myoglobin from Asian swamp eel Monopterus albus.

    Science.gov (United States)

    Chotichayapong, Chatrachatchaya; Wiengsamut, Kittipong; Chanthai, Saksit; Sattayasai, Nison; Tamiya, Toru; Kanzawa, Nobuyuki; Tsuchiya, Takahide

    2012-10-01

    Myoglobin from Asian swamp eel Monopterus albus was purified from fish muscle using salt fractionation followed by column chromatography and molecular filtration. The purified Mb of 0.68 mg/g wet weight of muscle was determined for its molecular mass by MALDI-TOF-MS to be 15,525.18 Da. Using isoelectric focusing technique, the purified Mb showed two derivatives with pI of 6.40 and 7.12. Six peptide fragments of this protein identified by LC-MS/MS were homologous to Mbs of sea raven Hemitripterus americanus, yellowfin tuna Thunnus albacores, blue marlin Makaira nigicans, common carp Cyprinus carpio, and goldfish Carassius auratus. According to the Mb denaturation, the swamp eel Mb had thermal stability higher than walking catfish Clarias batrachus Mb and striped catfish Pangasius hypophthalmus Mb, between 30 and 60 (°)C. For the thermal stability of Mb, the swamp eel Mb showed a biphasic behavior due to the O(2) dissociation and the heme orientation disorder, with the lowest increase in both Kd(f) and Kd(s). The thermal sensitivity of swamp eel Mb was lower than those of the other Mbs for both of fast and slow reaction stages. These results suggest that the swamp eel Mb globin structure is thermally stable, which is consistent with heat-tolerant behavior of the swamp eel particularly in drought habitat.

  1. Development and validation of a real-time PCR assay for the detection of anguillid herpesvirus 1.

    Science.gov (United States)

    van Beurden, S J; Voorbergen-Laarman, M A; Roozenburg, I; van Tellingen, J; Haenen, O L M; Engelsma, M Y

    2016-01-01

    Anguillid herpesvirus 1 (AngHV1) causes a haemorrhagic disease with increased mortality in wild and farmed European eel, Anguilla anguilla (L.) and Japanese eel Anguilla japonica, Temminck & Schlegel). Detection of AngHV1 is currently based on virus isolation in cell culture, antibody-based typing assays or conventional PCR. We developed, optimized and concisely validated a diagnostic TaqMan probe based real-time PCR assay for the detection of AngHV1. The primers and probe target AngHV1 open reading frame 57, encoding the capsid protease and scaffold protein. Compared to conventional PCR, the developed real-time PCR is faster, less labour-intensive and has a reduced risk of cross-contamination. The real-time PCR assay was shown to be analytically sensitive and specific and has a high repeatability, efficiency and r(2) -value. The diagnostic performance of the assay was determined by testing 10% w/v organ suspensions and virus cultures from wild and farmed European eels from the Netherlands by conventional and real-time PCR. The developed real-time PCR assay is a useful tool for the rapid and sensitive detection of AngHV1 in 10% w/v organ suspensions from wild and farmed European eels. © 2015 John Wiley & Sons Ltd.

  2. STATUS KESEHATAN IKAN SIDAT (Anguilla sp. PADA PERAIRAN UMUM DAN WADAH PEMELIHARAAN SEMENTARA

    Directory of Open Access Journals (Sweden)

    Agung Cahyo Setyawan

    2015-03-01

    Full Text Available Status kesehatan ikan sidat (Anguilla sp. telah dianalisis untuk menunjukkan terjadinya penurunan stok karena infeksi patogen dan penangkapan benih berlebihan untuk budidaya. Di Indonesia, ketiadaan standar penangkapan, pemeliharaan dan budidaya menyebabkan terjadinya penurunan kualitas dan kuantitas produksi ikan sidat. Penelitian ini dilakukan untuk mengevaluasi status kesehatan ikan sidat di perairan Indonesia dengan sampel dari Kabupaten Banyumas dan Cilacap, Jawa Tengah. Sampling dilakukan pada awal musim penghujan, yaitu bulan September hingga November 2012. Sebanyak 113 ekor ikan sidat ditangkap dan dianalisis dalam penelitian ini, dengan perincian 57 ekor diamati langsung setelah ditangkap dan 56 ekor diamati setelah dipelihara selama 10 hari oleh pengepul. Pengamatan dilakukan dengan metode observasi langsung menggunakan mikroskop untuk parasit, kit API 20NE (Biomeureux® untuk bakteri dan pewarnaan standar haematoxylin-eosin untuk histopatologi. Terdapat empat jenis parasit (Nematoda: Camallanidae dan Anguillicoloides; Platyhelminthes: Monogenea dan Digenea dan lima bakteri (Aeromonas hydrophylla, Pseudomonas luteola, Vibrio fluvialis, Aeromonas sobria, dan Aeromonas caviae dari sampel ikan sidat dalam penelitian ini. Tidak terdapat perbedaan dalam komposisi patogen, namun terjadi perubahan dalam kondisi histopatologi sehingga pemeliharaan sementara oleh pengepul sebelum ikan sidat dibudidayakan memiliki potensi menurunkan kualitas benih untuk budidaya.

  3. Linear chemically sensitive electron tomography using DualEELS and dictionary-based compressed sensing

    Energy Technology Data Exchange (ETDEWEB)

    AlAfeef, Ala, E-mail: a.al-afeef.1@research.gla.ac.uk [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); School of Computing Science, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Bobynko, Joanna [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Cockshott, W. Paul. [School of Computing Science, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Craven, Alan J. [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Zuazo, Ian; Barges, Patrick [ArcelorMittal Maizières Research, Maizières-lès-Metz 57283 (France); MacLaren, Ian, E-mail: ian.maclaren@glasgow.ac.uk [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2016-11-15

    We have investigated the use of DualEELS in elementally sensitive tilt series tomography in the scanning transmission electron microscope. A procedure is implemented using deconvolution to remove the effects of multiple scattering, followed by normalisation by the zero loss peak intensity. This is performed to produce a signal that is linearly dependent on the projected density of the element in each pixel. This method is compared with one that does not include deconvolution (although normalisation by the zero loss peak intensity is still performed). Additionally, we compare the 3D reconstruction using a new compressed sensing algorithm, DLET, with the well-established SIRT algorithm. VC precipitates, which are extracted from a steel on a carbon replica, are used in this study. It is found that the use of this linear signal results in a very even density throughout the precipitates. However, when deconvolution is omitted, a slight density reduction is observed in the cores of the precipitates (a so-called cupping artefact). Additionally, it is clearly demonstrated that the 3D morphology is much better reproduced using the DLET algorithm, with very little elongation in the missing wedge direction. It is therefore concluded that reliable elementally sensitive tilt tomography using EELS requires the appropriate use of DualEELS together with a suitable reconstruction algorithm, such as the compressed sensing based reconstruction algorithm used here, to make the best use of the limited data volume and signal to noise inherent in core-loss EELS. - Highlights: • DualEELS is essential for chemically sensitive electron tomography using EELS. • A new compressed sensing based algorithm (DLET) gives high fidelity reconstruction. • This combination of DualEELS and DLET will give reliable results from few projections.

  4. Diseases of eels in an international perspective: Workshop on Eel Diseases at the 15th International Conference on Diseases of Fish and Shellfish, Split, Croatia, 2011

    NARCIS (Netherlands)

    Haenen, O.L.M.; Mladineo, I.; Konecny, R.; Yoshimizu, M.; Groman, D.; Munoz, P.; Saraiva, A.; Bergmann, S.M.; Beurden, van S.J.

    2012-01-01

    In recent years, significant attention has been assigned to the decline in the wild freshwater eel stocks worldwide. Possible causative factors include fisheries (overfishing), habitat loss, migration barriers, and chemical pollution, and/or a combination of these factors. Infectious diseases

  5. Pseudoscorpions of the genera Pachyolpium, Novohorus and Amblyolpium (Pseudoscorpiones: Olpiidae) from St. Eustatius (Statia), St. Martin (Sint Maarten) and Anguilla (Lesser Antilles, Leeward group)

    NARCIS (Netherlands)

    Tooren, van den D.

    2002-01-01

    Two new species of pseudoscorpions are described: Pachyolpium confusum spec. nov. from St. Eustatius (Statia) and Amblyolpium martinensis spec. nov. from St. Martin (Sint Maarten). Another species: Novohorus incertus (Beier, 1931) is recorded from 2 new localities: Anguilla and St. Martin (Sint

  6. KEBIJAKAN TENTANG INTEGRASI AKTIVITAS PENANGKAPAN DENGAN PEMBUDIDAYAAN UNTUK KEBERLANJUTAN SUMBERDAYA IKAN SIDAT (Anguilla spp DI DAS POSO

    Directory of Open Access Journals (Sweden)

    Navy Novy Jefry Watupongoh

    2015-05-01

    Full Text Available Daerah Aliran Sungai (DAS Poso merupakan salah satu daerah penangkapan ikan sidat, memiliki luas 1.101,87 km2 dan panjang ± 68,70 km. Ikan sidat di perairan Poso merupakan komoditas perikanan yang memiliki nilai ekonomis tinggi (harga Rp.100.000,-/kg dan menjadi primadona hasil tangkapan. Ikan sidat yang hidup di DAS Poso terdapat 5 jenis, yaitu A. marmorata, A. bicolor pasific, A. celebensis, A. borneensis dan A. interioris. Saat ini telah terjadi penurunan produksi induk maupun glass eel ikan sidat di DAS Poso disebabkan oleh penangkapan yang belum memperhatikan faktor kelestarian dan keberlajutannya seperti penangkapan yang berlangsung tidak hanya pada saat induk ikan sidat yang beruaya ke laut tapi juga glas eel yang menuju ke danau. Pembangunan PLTA pada alur Sungai Poso mengganggu ruaya ikan sidat yang mengakibatkan terputusnya ruaya ikan sidat dari dan ke Danau Poso yang berakibat hilangnya ikan sidat di Danau Poso. Berkaitan dengan permasalahan ini maka populasi sumberdaya ikan sidat perlu dijaga keberlanjutannya dengan cara mengintegrasikan aktivitas penangkapan dengan pembudidayaan, oleh karena itu diperlukan kebijakan yang menetapkan peraturan terkait dengan penangkapan yang menggunakan alat tangkap ramah lingkungan serta diintegrasikan dengan pembudidayaan. Kajian kebijakan ini bertujuan untuk merumuskan kebijakan tentang integrasi aktivitas penagkapan dengan pembudidayaan untuk berkelanjutan ikan sidat di DAS Poso.   The watershed of Poso River is one of anguillid eel fishing areas. This watershed has an area of 1,101.87 km2 and length ± 68.70 miles. The anguillid eel is a commodity that has a high economic value (IDR 100,000 / kg and has an excellent catches. There are 5 types of eels that live in the watershed of Poso, they are: A. marmorata, A. bicolor pacific, A. celebensis, A. borneensis and A. interioris. The decreased production of anguillid parent and glass eels in the watershed of Poso is a result

  7. Regional variation in energy storage strategies in American glass eels from Eastern Canada.

    Science.gov (United States)

    Gaillard, Mélanie; Bernatchez, Louis; Tremblay, Réjean; Audet, Céline

    2015-10-01

    Energy status was analyzed in glass eels captured during two early waves of arrival at the mouths of the Mersey River, Nova Scotia, Canada (MR), and Grande-Rivière-Blanche, Québec, Canada (GRB), and according to their salinity preference (freshwater, brackish, or saltwater). Glass eels captured in the GRB estuary were larger, more pigmented, and exhibited higher whole-body glycogen, phospholipid, and sterol and wax ester contents. Those from MR had a higher condition index and a higher whole-body triacylglycerol content, suggesting different patterns of storage and/or use of energy reserves. Within a river, a delay of two weeks in estuarine arrival was characterized by significantly lower energy reserves. No differences in energy storage were observed according to salinity preference. Thus, the results revealed the occurrence of different energy storage strategies according to glass eel migration distance and duration, but not according to salinity preference. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Genome-wide single-generation signatures of local selection in the panmictic European eel

    DEFF Research Database (Denmark)

    Pujolar, J. M.; Jacobsen, M. W.; Als, Thomas Damm

    2014-01-01

    –receptor interaction and circadian rhythm. Remarkably, one of the candidate genes identified is PERIOD, possibly related to differences in local photoperiod associated with the >30° difference in latitude between locations. Genes under selection were spread across the genome, and there were no large regions...

  9. Ontogeny and growth of early life stages of captive-bred European eel

    DEFF Research Database (Denmark)

    Sørensen, Sune Riis; Tomkiewicz, Jonna; Munk, Peter

    2016-01-01

    post hatch at 20 °C, and were able to survive another ~10 dayswithout feeding. Larval length approached and symptotic maximum of 6.8mma round day 10 in non-fed larvae. Larval batches from different maternal origins varied in yolk sac size and the extent of yolk sac resources influenced larval size...

  10. Impacts of Interannual Ocean Circulation Variability on Japanese Eel Larval Migration in the Western North Pacific Ocean.

    Directory of Open Access Journals (Sweden)

    Yu-Lin Chang

    Full Text Available The Japanese eel larvae hatch near the West Mariana Ridge seamount chain and travel through the North Equatorial Current (NEC, the Kuroshio, and the Subtropical Countercurrent (STCC region during their shoreward migration toward East Asia. The interannual variability of circulation over the subtropical and tropical regions of the western North Pacific Ocean is affected by the Philippines-Taiwan Oscillation (PTO. This study examines the effect of the PTO on the Japanese eel larval migration routes using a three-dimensional (3D particle tracking method, including vertical and horizontal swimming behavior. The 3D circulation and hydrography used for particle tracking are from the ocean circulation reanalysis produced by the Japan Coastal Ocean Predictability Experiment 2 (JCOPE2. Our results demonstrate that bifurcation of the NEC and the strength and spatial variation of the Kuroshio affect the distribution and migration of eel larvae. During the positive phase of PTO, more virtual eels ("v-eels" can enter the Kuroshio to reach the south coast of Japan and more v-eels reach the South China Sea through the Luzon Strait; the stronger and more offshore swing of the Kuroshio in the East China Sea leads to fewer eels entering the East China Sea and the onshore movement of the Kuroshio to the south of Japan brings the eels closer to the Japanese coast. Significant differences in eel migration routes and distributions regulated by ocean circulation in different PTO phases can also affect the otolith increment. The estimated otolith increment suggests that eel age tends to be underestimated after six months of simulation due to the cooler lower layer temperature. Underestimation is more significant in the positive PTO years due to the wide distribution in higher latitudes than in the negative PTO years.

  11. Role of BK channels in the apoptotic volume decrease in native eel intestinal cells

    DEFF Research Database (Denmark)

    Lionetto, Maria Giulia; Giordano, Maria Elena; Calisi, Antonio

    2010-01-01

    High conductance Ca(+)-activated K(+) channels (BK channels) have previously been demonstrated in the eel intestine. They are specifically activated following a hypotonic stress and sustain Regulatory Volume Decrease (RVD). The aim of the present work was to address the possible role of these cha......High conductance Ca(+)-activated K(+) channels (BK channels) have previously been demonstrated in the eel intestine. They are specifically activated following a hypotonic stress and sustain Regulatory Volume Decrease (RVD). The aim of the present work was to address the possible role...

  12. Gnathostoma spinigerum in live Asian swamp eels (Monopterus spp.) from food markets and wild populations, United States

    Science.gov (United States)

    Cole, Rebecca A.; Choudhury, Anindo; Nico, Leo G.; Griffin, Kathryn M.

    2014-01-01

    In Southeast Asia, swamp eels (Synbranchidae: Monopterus spp.) are a common source of human gnathostomiasis, a foodborne zoonosis caused by advanced third-stage larvae (AL3) of Gnathostoma spp. nematodes. Live Asian swamp eels are imported to US ethnic food markets, and wild populations exist in several states. To determine whether these eels are infected, we examined 47 eels from markets and 67 wild-caught specimens. Nematodes were identified by morphologic features and ribosomal intergenic transcribed spacer–2 gene sequencing. Thirteen (27.7%) M. cuchia eels from markets were infected with 36 live G. spinigerum AL3: 21 (58.3%) in liver; 7 (19.4%) in muscle; 5 (13.8%) in gastrointestinal tract, and 3 (8.3%) in kidneys. Three (4.5%) wild-caught M. albus eels were infected with 5 G. turgidum AL3 in muscle, and 1 G. lamothei AL3 was found in a kidney (both North American spp.). Imported live eels are a potential source of human gnathostomiasis in the United States.

  13. The Effect of Drag and Attachment Site of External Tags on Swimming Eels: Experimental Quantification and Evaluation Tool

    Science.gov (United States)

    Tudorache, Christian; Burgerhout, Erik; Brittijn, Sebastiaan; van den Thillart, Guido

    2014-01-01

    Telemetry studies on aquatic animals often use external tags to monitor migration patterns and help to inform conservation effort. However, external tags are known to impair swimming energetics dramatically in a variety of species, including the endangered European eel. Due to their high swimming efficiency, anguilliform swimmers are very susceptibility for added drag. Using an integration of swimming physiology, behaviour and kinematics, we investigated the effect of additional drag and site of externally attached tags on swimming mode and costs. The results show a significant effect of a) attachment site and b) drag on multiple energetic parameters, such as Cost Of Transport (COT), critical swimming speed (Ucrit) and optimal swimming speed (Uopt), possibly due to changes in swimming kinematics. Attachment at 0.125 bl from the tip of the snout is a better choice than at the Centre Of Mass (0.35 bl), as it is the case in current telemetry studies. Quantification of added drag effect on COT and Ucrit show a (limited) correlation, suggesting that the Ucrit test can be used for evaluating external tags for telemetry studies until a certain threshold value. Uopt is not affected by added drag, validating previous findings of telemetry studies. The integrative methodology and the evaluation tool presented here can be used for the design of new studies using external telemetry tags, and the (re-) evaluation of relevant studies on anguilliform swimmers. PMID:25409179

  14. The effect of drag and attachment site of external tags on swimming eels: experimental quantification and evaluation tool.

    Science.gov (United States)

    Tudorache, Christian; Burgerhout, Erik; Brittijn, Sebastiaan; van den Thillart, Guido

    2014-01-01

    Telemetry studies on aquatic animals often use external tags to monitor migration patterns and help to inform conservation effort. However, external tags are known to impair swimming energetics dramatically in a variety of species, including the endangered European eel. Due to their high swimming efficiency, anguilliform swimmers are very susceptibility for added drag. Using an integration of swimming physiology, behaviour and kinematics, we investigated the effect of additional drag and site of externally attached tags on swimming mode and costs. The results show a significant effect of a) attachment site and b) drag on multiple energetic parameters, such as Cost Of Transport (COT), critical swimming speed (Ucrit) and optimal swimming speed (Uopt), possibly due to changes in swimming kinematics. Attachment at 0.125 bl from the tip of the snout is a better choice than at the Centre Of Mass (0.35 bl), as it is the case in current telemetry studies. Quantification of added drag effect on COT and Ucrit show a (limited) correlation, suggesting that the Ucrit test can be used for evaluating external tags for telemetry studies until a certain threshold value. Uopt is not affected by added drag, validating previous findings of telemetry studies. The integrative methodology and the evaluation tool presented here can be used for the design of new studies using external telemetry tags, and the (re-) evaluation of relevant studies on anguilliform swimmers.

  15. The effect of drag and attachment site of external tags on swimming eels: experimental quantification and evaluation tool.

    Directory of Open Access Journals (Sweden)

    Christian Tudorache

    Full Text Available Telemetry studies on aquatic animals often use external tags to monitor migration patterns and help to inform conservation effort. However, external tags are known to impair swimming energetics dramatically in a variety of species, including the endangered European eel. Due to their high swimming efficiency, anguilliform swimmers are very susceptibility for added drag. Using an integration of swimming physiology, behaviour and kinematics, we investigated the effect of additional drag and site of externally attached tags on swimming mode and costs. The results show a significant effect of a attachment site and b drag on multiple energetic parameters, such as Cost Of Transport (COT, critical swimming speed (Ucrit and optimal swimming speed (Uopt, possibly due to changes in swimming kinematics. Attachment at 0.125 bl from the tip of the snout is a better choice than at the Centre Of Mass (0.35 bl, as it is the case in current telemetry studies. Quantification of added drag effect on COT and Ucrit show a (limited correlation, suggesting that the Ucrit test can be used for evaluating external tags for telemetry studies until a certain threshold value. Uopt is not affected by added drag, validating previous findings of telemetry studies. The integrative methodology and the evaluation tool presented here can be used for the design of new studies using external telemetry tags, and the (re- evaluation of relevant studies on anguilliform swimmers.

  16. Determination of some individual chlorobiphenyls in eel-fat with capillary gaschromatography: collaborative study

    NARCIS (Netherlands)

    Tuinstra, L.G.M.T.; Roos, A.H.; Werdmuller, G.A.

    1984-01-01

    A method for the determination of six individual chlorobiphenyls in eel-fat, based on saponification of the sample and determination with capillary gas chromatography, was studied collaboratively. Eleven laboratories submitted analytical results in duplo of six individual chlorbiphenyls on two

  17. Teaching Population Growth Using Cultures of Vinegar Eels, "Turbatrix aceti" (Nematoda)

    Science.gov (United States)

    Wallace, Robert L.

    2005-01-01

    A simple laboratory exercise is presented that follows the population growth of the common vinegar eel, "Turbatrix aceti" (Nematoda), in a microcosm using a simple culture medium. It lends itself to an exercise in a single semester course. (Contains 4 figures.)

  18. Survival and growth compared between wild and farmed eel stocked in freshwater ponds

    DEFF Research Database (Denmark)

    Pedersen, Michael Ingemann; Jepsen, Niels; Rasmussen, Gorm

    2017-01-01

    conducted in a series of shallow, open ponds of approximately 200 m2. Wild and farmed eels were batch tagged, mixed and released in the ponds at an initial density of 0.5 individual/m2. Survival was rather high (34–88%) with variations between ponds. No significant difference in survival was found between...

  19. TEM and EELS studies of microwave-irradiation synthesis of bimetallic platinum nanocatalysts

    CSIR Research Space (South Africa)

    Mathe, NR

    2014-01-01

    Full Text Available to conventional methods. In this work, microwave-irradiation was used to produce platinum-cobalt (Pt-Co) and platinum-nickel (Pt-Ni) nanoparticles for use as electrocatalysts in the methanol oxidation reaction. High resolution TEM imaging and EELS studies revealed...

  20. Sub-decadal turbidite frequency during the early Holocene: Eel Fan, offshore northern California

    Science.gov (United States)

    Paull, Charles K.; McGann, Mary L.; Sumner, Esther J; Barnes, Philip M; Lundsten, Eve M.; Anderson, Krystle; Gwiazda, Roberto; Edwards, Brian D.; Caress, David W

    2014-01-01

    Remotely operated and autonomous underwater vehicle technologies were used to image and sample exceptional deep sea outcrops where an ∼100-m-thick section of turbidite beds is exposed on the headwalls of two giant submarine scours on Eel submarine fan, offshore northern California (USA). These outcrops provide a rare opportunity to connect young deep-sea turbidites with their feeder system. 14C measurements reveal that from 12.8 ka to 7.9 ka, one turbidite was being emplaced on average every 7 yr. This emplacement rate is two to three orders of magnitude higher than observed for turbidites elsewhere along the Pacific margin of North America. The turbidites contain abundant wood and shallow-dwelling foraminifera, demonstrating an efficient connection between the Eel River source and the Eel Fan sink. Turbidite recurrence intervals diminish fivefold to ∼36 yr from 7.9 ka onward, reflecting sea-level rise and re-routing of Eel River sediments.

  1. Push net fishing seems to be responsible for injuries and post fishing mortality in glass eel in the Vilaine estuary (France in 2007

    Directory of Open Access Journals (Sweden)

    Briand C.

    2012-01-01

    Full Text Available Post fishing mortality of the glass eel was monitored in 2007 in the Vilaine estuary. The mortality of the glass eels varied from 2 to 82% (mean 42% in the two days following the fishing. The mortality of samples collected by hand nets or from the trapping ladder was null. Alterations of the skin mucus were analyzed by the use of Indigo carmine. The mortality was significantly correlated with body injuries, but not to other environmental factors. The presence of a large injury on the body systematically led to the death of the glass eels, and among these dead glass eels, only 3.5% had no external injury. These results are discussed, along with the results from other estuaries, with a view to transport glass eels across Europe, with the objective of restoring the eel stock.

  2. Application of STEM/EELS to Plasmon-Related Effects in Optical Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Camden, Jon P. [Univ. of Tennessee, Knoxville, TN (United States)

    2015-01-29

    The last decade has seen an explosion in the study of plasmonic materials, with current applications including surface-enhanced spectroscopy, imaging beyond the diffraction limit, solar energy harvesting, and ultrasensitive detection. This proposal utilizes electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM) to explore the near-field enhancements encountered upon excitation of the localized surface plasmon resonance. In particular we have studied Fano interferences using optical and electron energy-loss spectroscopies (EELS). Single silver nanocubes were utilized in this study due to the substrate-mediated hybridization of the primitive dipolar and quadrupolar plasmon modes that give rise to the Fano phenomenon. The cube at substrate system provides a unique opportunity to study the plasmonic energy transfer from metallic nanoparticles to neighboring materials, which is an essential component of plasmon-enhanced solar harvesting devices.

  3. Cell cultures and retroviral particles from a tumor of a moray eel.

    Science.gov (United States)

    Buck, C; Walsh, C; Davis, R; Toumadje, A; Kusamoto, K; Helmrich, A; Chapline, C; Mericko, P; Barnes, D

    2001-06-01

    Until recently, fish cell culture primarily has been useful only in the propagation and study of epidemic viruses significant to the fishing industry. Such fish cell lines derived were developed by appropriating classical techniques of mammalian cell culture, with serum as the major growth supplement. Using an approach in which culture medium is formulated in a cell-type-specific manner with minimal serum and a variety of synergistic supplements, several fish cell lines have been derived that may serve multiple uses. We established cell lines from a potentially tumorous skin lesion of a green moray eel (Gymnothorax funebris) and control tissues, and identified putative retroviral particles in the medium from the tumor cells that are not present in medium from cultures of normal cells from the same eel. The relationship between the virus and the cause of the tumor is not clear, but the genomic structure of this virus should provide useful information in understanding the evolution of retroviruses in general.

  4. An introduction to the calculation of valence EELS: quantum mechanical methods for bulk solids.

    Science.gov (United States)

    Keast, V J

    2013-01-01

    The low-loss region of the electron energy-loss spectrum, the valence EELS, provides information about the electronic structure and optical properties of materials. For bulk materials the spectral intensity can be directly connected to the complex dielectric function. Ab initio quantum mechanical calculations have an important role to play in the interpretation of the fine spectral detail and how this can be connected to the material properties. This paper provides an overview of theoretical background to the calculation of valence EELS in bulk solids and gives specific details on how to run such calculations using the WIEN2k code. The comparison of Au and AuAl(2) illustrates how in metals such calculations are successful in reproducing the main spectral details and can be used to understand the origin of the different colours of these two metals. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Spectrum image analysis tool - A flexible MATLAB solution to analyze EEL and CL spectrum images.

    Science.gov (United States)

    Schmidt, Franz-Philipp; Hofer, Ferdinand; Krenn, Joachim R

    2017-02-01

    Spectrum imaging techniques, gaining simultaneously structural (image) and spectroscopic data, require appropriate and careful processing to extract information of the dataset. In this article we introduce a MATLAB based software that uses three dimensional data (EEL/CL spectrum image in dm3 format (Gatan Inc.'s DigitalMicrograph ® )) as input. A graphical user interface enables a fast and easy mapping of spectral dependent images and position dependent spectra. First, data processing such as background subtraction, deconvolution and denoising, second, multiple display options including an EEL/CL moviemaker and, third, the applicability on a large amount of data sets with a small work load makes this program an interesting tool to visualize otherwise hidden details. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. A new method to grade glass eels according to their appetite

    Directory of Open Access Journals (Sweden)

    ANGELIDIS Panagiotis

    2007-10-01

    Full Text Available To optimize fish growth grading is strongly recommended. In our experiment the glass eels (450,000, mean individual body weight 0.31+0.22g sd start feeding for 15 and then they were selected according to their appetite. After selection all the fish of the 10 tanks were fed at liberty and they were weighed on the 10th and 30thday after the grade day. No differences were seen in the fish weight of the eels of the two groups on the 10th day (P>0.01 but the selected fish doubled their weight on the 30th day (selected fish 0.71+0.22g sd, unselected 0.39+0.20g sd, P<0.01.

  7. Nanoscale Chemical Evolution of Silicon Negative Electrodes Characterized by Low-Loss STEM-EELS

    CERN Document Server

    Boniface, Maxime; Danet, Julien; Guyomard, Dominique; Moreau, Philippe; Bayle-Guillemaud, Pascale

    2016-01-01

    Continuous solid electrolyte interface (SEI) formation remains the limiting factor of the lifetime of silicon nanoparticles (SiNPs) based negative electrodes. Methods that could provide clear diagnosis of the electrode degradation are of utmost necessity to streamline further developments. We demonstrate that electron energy-loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM) can be used to quickly map SEI components and quantify LixSi alloys from single experiments, with resolutions down to 5 nm. Exploiting the low-loss part of the EEL spectrum allowed us to circumvent the degradation phenomena that have so far crippled the application of this technique on such beam-sensitive compounds. Our results provide unprecedented insight into silicon aging mechanisms in full cell configuration. We observe the morphology of the SEI to be extremely heterogeneous at the particle scale but with clear chemical evolutions with extended cycling coming from both SEI accumulation and a transition fro...

  8. Pollution fingerprints in eels as models for the chemical status of rivers

    OpenAIRE

    Belpaire, C.; Goemans, G.; Geeraerts, C.; Quataert, P.; Parmentier, K.

    2008-01-01

    The 2006 EU Water Framework Directive (WFD) proposed the monitoring of a selection of priority substances in the aquatic phase, including lipophilic substances. However, there are strong arguments for measuring lipophilic substances in biota. Yellow eel is a good candidate because it is widespread, sedentary, and accumulates many lipophilic substances in its muscle tissue. Several authors have described the indicative value of measured concentrations, yet few studies have investigated to what...

  9. A complete overhaul of the EELS and XAS database: eelsdb.eu

    OpenAIRE

    Ewels, Philip; Sikora, Thierry; Serin, Virginie; Ewels, Chris P.; Lajaunie, Luc

    2016-01-01

    The Electron Energy-Loss Spectroscopy (EELS) and X-ray Absorption Spectroscopy (XAS) database has been completely rewritten, with an improved design, user interface and a number of new tools. The database is accessible at https://eelsdb.eu/ and can now be used without registration. The submission process has been streamlined to encourage spectrum submissions and the new design gives greater emphasis on contributors original work by highlighting their papers. With numerous new filters and a po...

  10. Proteomic analysis of three gonad types of swamp eel reveals genes differentially expressed during sex reversal

    OpenAIRE

    Yue Sheng; Wei Zhao; Ying Song; Zhigang Li; Majing Luo; Quan Lei; Hanhua Cheng; Rongjia Zhou

    2015-01-01

    A variety of mechanisms are engaged in sex determination in vertebrates. The teleost fish swamp eel undergoes sex reversal naturally and is an ideal model for vertebrate sexual development. However, the importance of proteome-wide scanning for gonad reversal was not previously determined. We report a 2-D electrophoresis analysis of three gonad types of proteomes during sex reversal. MS/MS analysis revealed a group of differentially expressed proteins during ovary to ovotestis to testis transf...

  11. Mise en évidence des déplacements d'anguilles sédentaires (Anguilla anguilla L. en relation avec le cycle lunaire dans le lac de Grand-Lieu (Loire-Atlantique

    Directory of Open Access Journals (Sweden)

    ADAM G.

    1994-10-01

    Full Text Available Nous cherchons par ce travail à mettre en évidence l'influence du cycle lunaire sur les déplacements d'anguilles européennes sédentaires (Anguilla anguilla L. 1758. L'évolution des captures par engin de pêche passif révèle les déplacements de l'anguille. Un système de carnet de pêche journalier a été mis en place en relation avec la pêcherie professionnelle du lac de Grand-Lieu (Loire-Atlantique. Il permet de collecter des données fines de capture. Cet article présente l'analyse des fluctuations journalières des prises par unité d'effort (CPUE d'anguille européenne sur une période de deux ans (1991 et 1992. Deux éléments ressortent de cette étude. Tout d'abord, la série chronologique des CPUE suit une tendance annuelle qui la conduit de valeurs hivernales plutôt faibles aux valeurs estivales et automnales fortes. Mais à l'intérieur de cette tendance annuelle des variations plus courtes se dessinent. La recherche d'un événement cyclique par la transformée de FOURIER n'a donné que des résultats imprécis. Mais un filtrage «passe-bas» des données a, par contre, permis de confirmer l'hypothèse émise sur l'existence d'une périodicité d'événements autour de 28 jours. Cette périodicité correspond parfaitement au cycle lunaire. Enfin, il est proposé d'affiner l'étude par l'analyse des relations entre les CPUE et les données environnementales de type météorologique.

  12. Interspecific communicative and coordinated hunting between groupers and giant moray eels in the Red Sea.

    Directory of Open Access Journals (Sweden)

    Redouan Bshary

    2006-12-01

    Full Text Available Intraspecific group hunting has received considerable attention because of the close links between cooperative behaviour and its cognitive demands. Accordingly, comparisons between species have focused on behaviours that can potentially distinguish between the different levels of cognitive complexity involved, such as "intentional" communication between partners in order to initiate a joint hunt, the adoption of different roles during a joint hunt (whether consistently or alternately, and the level of food sharing following a successful hunt. Here we report field observations from the Red Sea on the highly coordinated and communicative interspecific hunting between the grouper, Plectropomus pessuliferus, and the giant moray eel, Gymnothorax javanicus. We provide evidence of the following: (1 associations are nonrandom, (2 groupers signal to moray eels in order to initiate joint searching and recruit moray eels to prey hiding places, (3 signalling is dependent on grouper hunger level, and (4 both partners benefit from the association. The benefits of joint hunting appear to be due to complementary hunting skills, reflecting the evolved strategies of each species, rather than individual role specialisation during joint hunts. In addition, the partner species that catches a prey item swallows it whole immediately, making aggressive monopolisation of a carcass impossible. We propose that the potential for monopolisation of carcasses by one partner species represents the main constraint on the evolution of interspecific cooperative hunting for most potentially suitable predator combinations.

  13. Anisakis pegreffii Larvae in Sea Eels (Astroconger myriaster) from the South Sea, Republic of Korea.

    Science.gov (United States)

    Cho, Jaeeun; Lim, Hyemi; Jung, Bong-Kwang; Shin, Eun-Hee; Chai, Jong-Yil

    2015-06-01

    Anisakis simplex sensu stricto (s.s.), Anisakis pegreffii, Anisakis berlandi (=A. simplex sp. C), and Anisakis typica are the 4 major species of Anisakis type I larvae. In the Republic of Korea (Korea), A. pegreffii, A. berlandi, and A. typica larvae in fish hosts has seldom been documented. In this study, molecular analysis was performed on Anisakis larvae from the sea eels (Astroconger myriaster), the major source of human anisakiasis in Korea, collected from Tongyeong City, a southern coastal area of Korea. All 20 sea eels examined were infected with Anisakis type I larvae (160 larvae; 8 per fish). Their species were analyzed using PCR-RFLP patterns and nucleotide sequences of internal transcribed spacers (ITS1, 5.8 subunit gene, and ITS2) and mitochondrial cytochrome c oxidase 2 (cox2). Most (86.8%; 112/129) of the Anisakis type I larvae were A. pegreffii, and 7.8% (10/129) were A. typica. The remaining 5.4% (7/129) was not identified. Thus, A. pegreffii is the major species of anisakid larvae in sea eels of the southern coast of Korea.

  14. Genetic identification of marine eels through DNA barcoding from Parangipettai coastal waters

    Directory of Open Access Journals (Sweden)

    Samuel Peninal

    2017-03-01

    Full Text Available Anguilliformes, also known as “true eels”, are an ecologically diverse group of predominantly marine origin whose members were easily recognized by their extremely elongated bodies with reduced cross-sectional areas and universal lack of pelvic fins. The Marine Eels were collected from landing centres of Parangipettai coastal waters and identified based on their morphometric and meristic characters. The newly recorded species were used for the barcoding analysis. Information on molecular taxonomy of marine eels was very meagre and hence, the present study was aimed to study the barcoding of marine eels which were present along the southeast coast of India. The cube of lateral muscle was exercised for DNA isolation followed by its amplification. Cluster IX 2.06 was used to align the nucleotide sequences (Thomson, 1997. The evolutionary history was inferred using the Neighbor-Joining method (Saitou and Nei, 1987. The evolutionary distances were computed using the Maximum Composite Likelihood method (Tamura et al., 2004. The barcodes sequences were submitted in NCBI (National centre for Biotechnological Information. The species within genera of Muraenidae, Muraenesocidae and Ophichthidae family were clustered in a same clade with high bootstrap value. The evolutionary relationships of six species were analyzed using neighbor joining method. This results of phylogenetic tree showed maximum genetic relatedness with the sequenced results which were submitted in gene bank.

  15. Use of speleologic data to evaluate Holocene uplifting and tilting: an example from the Frasassi anticline (northeastern Apennines, Italy).

    NARCIS (Netherlands)

    Mariani, S.; Mainiero, M.; Barchi, M.; van der Borg, K.; Vonhof, H.B.; Montanari, A.

    2007-01-01

    Deep inside the Frasassi cave complex in the foreland fold and thrust belt of the northeastern Apennines (central Italy), the remains of hundreds of eels (Anguilla anguilla) are found scattered on the shores of phreatic lakes up to 5 m above the water table. These sub-fossil eels, and the

  16. Use of speleologic data to evaluate Holocene uplifting and tilting: an example from the Frasassi anticline (northeastern Apennines, Italy)

    NARCIS (Netherlands)

    Mariani, S.; Mainiero, M.; Barchi, M.; van der Borg, K.|info:eu-repo/dai/nl/067895298; Vonhof, H.B.; Montanari, A.

    2007-01-01

    Deep inside the Frasassi cave complex in the foreland fold and thrust belt of the northeastern Apennines (central Italy), the remains of hundreds of eels (Anguilla anguilla) are found scattered on the shores of phreatic lakes up to 5 m above the water table. These sub-fossil eels, and the

  17. Imported Asian swamp eels (Synbranchidae: Monopterus) in North American live food markets: Potential vectors of non-native parasites

    Science.gov (United States)

    Nico, Leo G.; Sharp, Paul; Collins, Timothy M.

    2011-01-01

    Since the 1990s, possibly earlier, large numbers of Asian swamp eels (Synbranchidae: Monopterus spp.), some wild-caught, have been imported live from various countries in Asia and sold in ethnic food markets in cities throughout the USA and parts of Canada. Such markets are the likely introduction pathway of some, perhaps most, of the five known wild populations of Asian swamp eels present in the continental United States. This paper presents results of a pilot study intended to gather baseline data on the occurrence and abundance of internal macroparasites infecting swamp eels imported from Asia to North American retail food markets. These data are important in assessing the potential role that imported swamp eels may play as possible vectors of non-native parasites. Examination of the gastrointestinal tracts and associated tissues of 19 adult-sized swamp eels—identified as M. albus "Clade C"—imported from Vietnam and present in a U.S. retail food market revealed that 18 (95%) contained macroparasites. The 394 individual parasites recovered included a mix of nematodes, acanthocephalans, cestodes, digeneans, and pentastomes. The findings raise concern because of the likelihood that some parasites infecting market swamp eels imported from Asia are themselves Asian taxa, some possibly new to North America. The ecological risk is exacerbated because swamp eels sold in food markets are occasionally retained live by customers and a few reportedly released into the wild. For comparative purposes, M. albus "Clade C" swamp eels from a non-native population in Florida (USA) were also examined and most (84%) were found to be infected with internal macroparasites. The current level of analysis does not allow us to confirm whether these are non-native parasites.

  18. PENGARUH PENGGUNAAN TEPUNG SILASE DAUN MENGKUDU (Morinda citrifolia DALAM FORMULA PAKAN TERHADAP PERTUMBUHAN IKAN SIDAT (Anguilla bicolor STADIA ELVER

    Directory of Open Access Journals (Sweden)

    Dewi Cholifah

    2012-10-01

    Full Text Available Penelitian ini dilakukan untuk mengetahui pengaruh dan dosis terbaik penggunaan tepung silase daun Mengkudu (M. citrifolia dalam formula pakan terhadap pertumbuhan ikan Sidat (A. bicolor stadia elver. Penelitian dibagi menjadi dua tahap, tahap pertama formulasi pakan percobaan, dan tahap kedua uji in vivo/uji formula pakan percobaan skala laboratorium pada ikan Sidat. Pelaksanaan penelitian tahap 1 adalah membuat formula pakan iso protein (40% dan iso energi (3.600 kkal/kg pakan dengan memanfaatkan tepung silase daun Mengkudu sesuai perlakuan, menggunakan metode lembar kerja. Penelitian tahap 2 berdasarkan Rancangan Acak Lengkap (RAL dengan tiga ulangan. Empat perlakuan substitusi protein tepung silase daun Mengkudu terhadap protein tepung ikan yang berbeda, meliputi perlakuan A 0%(0:100; B 10%(10:90; C 20%(20:80 dan D 30%(30:70. Parameter utama adalah kelulushidupan (survival rate, laju pertumbuhan spesifik (specific growth rate, rasio konversi pakan (feed convertion ratio dan rasio efisiensi protein (protein efficiency ratio. Hasil penelitian menunjukkan bahwa penggunaan tepung silase daun Mengkudu dalam formula pakan berpengaruh nyata terhadap parameter laju pertumbuhan spesifik, rasio konversi pakan dan rasio efisiensi protein. Dosis terbaik tepung silase daun Mengkudu  mensubstitusi protein tepung ikan dalam formula pakan sebesar 14,71 – 15% yang menghasilkan nilai laju pertumbuhan spesifik 0,72 %BB/hari, rasio konversi pakan 3,38, dan rasio efisiensi protein 0,718.Kata kunci: formula pakan, silase daun Morinda citrifolia, Anguilla bicolor

  19. TEM and EELS study of deuterated carbon: application to the fuel retention in tokamaks; Etude couplee MET-EELS du carbone deutere: application a la retention du combustible dans les tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Bernier, N

    2007-12-15

    We developed a methodology, based on the combination of TEM and EELS techniques, for a structural and chemical characterization, at a high spatial resolution, of a wide range of carbon materials. We i) optimized, in the framework of theoretical models, the sp2 fraction quantification from pure carbons by EELS ii) transferred this quantification to deuterated amorphous carbon layers iii) showed, from graphitized carbons, how the TEM-EELS combination allows to detect low concentrations of implanted D. Due to the accomplishment of these developments, we applied our approach to the study of D retention in composites C/C, which are the plasma-facing materials in TS. We showed that specific localized retention sites correspond to relatively large ({approx} 3 mm.) cracks between fibres and matrix; such cracks offer a simple and direct path for deuterated amorphous carbon. The particle balance performed in TS is discussed in the light of this trapping mechanism. (author)

  20. Combined mitochondrial DNA analysis of the Mesopotamian spiny eel, Mastacembelus mastacembelus (Banks & Solander 1794, and its phylogenetic position

    Directory of Open Access Journals (Sweden)

    Esen Tutar

    2015-11-01

    Full Text Available Nucleotide sequences of the 12S rRNA, 16S rRNA, tRNAPhe and tRNAVal genes of mtDNA of the Mesopotamian spiny eel, M. mastacembelus was determined for the first time. The comparison of the three populations of Mesopotamian spiny eel from Turkish part of the Tigris basin based on the obtained combined mitochondrial DNA was performed. Based on the results, no differences were determined and the identity found to be 100% among three populations. Furthermore, the obtained results from molecular methods were compared with morphological findings to validate the position of the studied populations of M. mastacembelus. In addition, the phylogenetic position of the Mesopotamian spiny eel was examined among the Mastacembelidae and Synbranchioformes based on 12S rRNA and 16S rRNA. The constructed phylogenetic relationship between M. mastacembelus and some other members of Synbranchioformes order supported their taxonomic hierarchy.

  1. Accurate measurement of absolute experimental inelastic mean free paths and EELS differential cross-sections

    Energy Technology Data Exchange (ETDEWEB)

    Craven, Alan J.; Bobynko, Joanna; Sala, Bianca; MacLaren, Ian, E-mail: ian.maclaren@glasgow.ac.uk

    2016-11-15

    Methods are described for measuring accurate absolute experimental inelastic mean free paths and differential cross-sections using DualEELS. The methods remove the effects of surface layers and give the results for the bulk materials. The materials used are VC{sub 0.83}, TiC{sub 0.98}, VN{sub 0.97} and TiN{sub 0.88} but the method should be applicable to a wide range of materials. The data was taken at 200 keV using a probe half angle of 29 mrad and a collection angle of 36 mrad. The background can be subtracted from under the ionisation edges, which can then be separated from each other. This is achieved by scaling Hartree-Slater calculated cross-sections to the edges in the atomic regions well above the threshold. The average scaling factors required are 1.00 for the non-metal K-edges and 1.01 for the metal L-edges (with uncertainties of a few percent). If preliminary measurements of the chromatic effects in the post-specimen lenses are correct, both drop to 0.99. The inelastic mean free path for TiC{sub 0.98} was measured as 103.6±0.5 nm compared to the prediction of 126.9 nm based on the widely used Iakoubovskii parameterisation. - Highlights: • We show how to extract absolute cross sections for EELS edges using DualEELS. • The method removes the effects of any surface layers on standards. • We use a needle specimen to determining the mean free path for inelastic scattering. • Constrained background fitting is essential to correct background subtraction. • Absolute cross sections are determined for TiC, TiN, VC and VN.

  2. Sparse modeling of EELS and EDX spectral imaging data by nonnegative matrix factorization

    Energy Technology Data Exchange (ETDEWEB)

    Shiga, Motoki, E-mail: shiga_m@gifu-u.ac.jp [Department of Electrical, Electronic and Computer Engineering, Gifu University, 1-1, Yanagido, Gifu 501-1193 (Japan); Tatsumi, Kazuyoshi; Muto, Shunsuke [Advanced Measurement Technology Center, Institute of Materials and Systems for Sustainability, Nagoya University, Chikusa-ku, Nagoya 464-8603 (Japan); Tsuda, Koji [Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8561 (Japan); Center for Materials Research by Information Integration, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology, 2-4-7 Aomi Koto-ku, Tokyo 135-0064 (Japan); Yamamoto, Yuta [High-Voltage Electron Microscope Laboratory, Institute of Materials and Systems for Sustainability, Nagoya University, Chikusa-ku, Nagoya 464-8603 (Japan); Mori, Toshiyuki [Environment and Energy Materials Division, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan); Tanji, Takayoshi [Division of Materials Research, Institute of Materials and Systems for Sustainability, Nagoya University, Chikusa-ku, Nagoya 464-8603 (Japan)

    2016-11-15

    Advances in scanning transmission electron microscopy (STEM) techniques have enabled us to automatically obtain electron energy-loss (EELS)/energy-dispersive X-ray (EDX) spectral datasets from a specified region of interest (ROI) at an arbitrary step width, called spectral imaging (SI). Instead of manually identifying the potential constituent chemical components from the ROI and determining the chemical state of each spectral component from the SI data stored in a huge three-dimensional matrix, it is more effective and efficient to use a statistical approach for the automatic resolution and extraction of the underlying chemical components. Among many different statistical approaches, we adopt a non-negative matrix factorization (NMF) technique, mainly because of the natural assumption of non-negative values in the spectra and cardinalities of chemical components, which are always positive in actual data. This paper proposes a new NMF model with two penalty terms: (i) an automatic relevance determination (ARD) prior, which optimizes the number of components, and (ii) a soft orthogonal constraint, which clearly resolves each spectrum component. For the factorization, we further propose a fast optimization algorithm based on hierarchical alternating least-squares. Numerical experiments using both phantom and real STEM-EDX/EELS SI datasets demonstrate that the ARD prior successfully identifies the correct number of physically meaningful components. The soft orthogonal constraint is also shown to be effective, particularly for STEM-EELS SI data, where neither the spatial nor spectral entries in the matrices are sparse. - Highlights: • Automatic resolution of chemical components from spectral imaging is considered. • We propose a new non-negative matrix factorization with two new penalties. • The first penalty is sparseness to choose the number of components from data. • Experimental results with real data demonstrate effectiveness of our method.

  3. NbC precipitates EELS spectra in a very low carbon microalloyed steel

    Directory of Open Access Journals (Sweden)

    Mancilla, J. E.

    2004-06-01

    Full Text Available In this paper a characterization study by transmission electron microscopy (TEM and electron energy loss spectroscopy (EELS of NbC precipitates in microalloyed steel is presented. The steel was hot rolled in a laboratory scale two-high reversing mill. The shape, size, location, and number of particles per unit area in the steel microstructure are reported. The particles were semi quantitatively analyzed for the heavier alloying elements using EDS, while EELS was used for the lighter elements, e. g. carbon and nitrogen. The EELS study of the precipitates reveals that the carbon is present as a compound (NbC without nitrogen.

    En este trabajo se presenta un estudio de caracterización por espectroscopia de pérdida de energía de electrones (EPEE realizado en un microscopio electrónico de transmisión de los precipitados de NbC en un acero microaleado. El acero se laminó en caliente en un laminador dúo reversible escala laboratorio. Las partículas de precipitados se caracterizaron en tamaños, formas y distribución y se analizaron semicuantitativamente para los elementos de aleación del acero más pesados, empleando un detector por dispersión de energías de rayos X, mientras que la EPEE se empleó para los elementos más ligeros, es decir, el carbono y el nitrógeno. El estudio por EPEE de los precipitados muestra que el carbono está presente como un compuesto (NbC sin que se haya encontrado nitrógeno en los mismos.

  4. Application of Generalized Mie Theory to EELS Calculations as a Tool for Optimization of Plasmonic Structures

    DEFF Research Database (Denmark)

    Thomas, Stefan; Matyssek, Christian; Hergert, Wolfram

    2015-01-01

    Technical applications of plasmonic nanostructures require a careful structural optimization with respect to the desired functionality. The success of such optimizations strongly depends on the applied method. We extend the generalized multiparticle Mie (GMM) computational electromagnetic method...... and use it to excite a system of plasmonic nanoparticles with an electron beam. This method is applied to EELS calculations of a gold dimer and compared to other methods. It is demonstrated that the GMM method is so efficient, that it can be used in the context of structural optimization...

  5. Application of STEM/EELS to Plasmon-Related Effects in Optical Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Camden, Jon [Univ. of Notre Dame, IN (United States). Dept. of Chemistry and Biochemistry

    2017-08-15

    In this project we employed EELS/STEM to understand the near-field enhancements that drive current applications of plasmonic nanostructures. In particular, we explore the connection between optical and electron excitation of plasmon modes in metallic nanostructures: (1) Probing the structural parameters and dielectric properties of multimetallic nanoparticles; (2) Characterization of the near-electric-field enhancements obtained upon excitation of the localized surface plasmon resonance and understand the connection between electron- and photon-driven plasmons; (3) Understanding the behavior of molecules in plasmon-enhanced fields which is essential to emerging applications such as plasmon-assisted catalysis and solar energy harvesting.

  6. Phenolic Lipids Affect the Activity and Conformation of Acetylcholinesterase from Electrophorus electricus (Electric eel)

    Science.gov (United States)

    Stasiuk, Maria; Janiszewska, Alicja; Kozubek, Arkadiusz

    2014-01-01

    Phenolic lipids were isolated from rye grains, cashew nutshell liquid (CNSL) from Anacardium occidentale, and fruit bodies of Merrulius tremellosus, and their effects on the electric eel acetylcholinesterase activity and conformation were studied. The observed effect distinctly depended on the chemical structure of the phenolic lipids that were available for interaction with the enzyme. All of the tested compounds reduced the activity of acetylcholinesterase. The degree of inhibition varied, showing a correlation with changes in the conformation of the enzyme tested by the intrinsic fluorescence of the Trp residues of the protein. PMID:24787269

  7. AN IMPROVED WHITE CELL DILUENT FOR USE WITH THE EEL ELECTRONIC BLOOD CELL COUNTER

    Science.gov (United States)

    Taylor, F.; Rickards, A. G.

    1960-01-01

    An improved white cell diluent for use with the Eel electronic counter is described. It possesses advantages over previously described diluents in the rapidity of its action as a red cell stromalysin and in its ability to conserve surviving leucocytes for long periods of time. These properties enable counts to be made either immediately after preparation of the suspension or several hours later. The diluent is equally suitable for use with capillary or venous blood samples. When used for counting leucocytes it has been found necessary to effect a minor modification to the machine whereby the light intensity is reduced by approximately one-half. PMID:13837137

  8. Transcriptome analyses of Anguillicola crassus from native and novel hosts

    Directory of Open Access Journals (Sweden)

    Emanuel Heitlinger

    2014-11-01

    Full Text Available Anguillicola crassus is a swim bladder nematode of eels. The parasite is native to the Asian eel Anguilla japonica, but was introduced to Europe and the European eel Anguilla anguilla in the early 1980s. A Taiwanese source has been proposed for this introduction. In the new host in the recipient area, the parasite appears to be more pathogenic. As a reason for these differences, genetically fixed differences in infectivity and development between Taiwanese and European A.crassus have been described and disentangled from plasticity induced by different host environments. To explore whether transcriptional regulation is involved in these lifecycle differences, we have analysed a “common garden”, cross infection experiment, using deep-sequencing transcriptomics. Surprisingly, in the face of clear phenotypic differences in life history traits, we identified no significant differences in gene expression between parasite populations or between experimental host species. From 120,000 SNPs identified in the transcriptome data we found that European A. crassus were not a genetic subset of the Taiwanese nematodes sampled. The loci that have the major contribution to the European-Taiwanese population differentiation show an enrichment of synonymous and non-coding polymorphism. This argues against positive selection in population differentiation. However, genes involved in protein processing in the endoplasmatic reticulum membrane and genes bearing secretion signal sequences were enriched in the set of genes most differentiated between European and Taiwanese A. crassus. These genes could be a source for the phenotypically visible genetically fixed differences between European and Taiwanese A. crassus.

  9. Single-Molecule Surface-Enhanced Raman Scattering: Can STEM/EELS Image Electromagnetic Hot Spots?

    Science.gov (United States)

    Mirsaleh-Kohan, Nasrin; Iberi, Vighter; Simmons, Philip D; Bigelow, Nicholas W; Vaschillo, Alex; Rowland, Meng M; Best, Michael D; Pennycook, Stephen J; Masiello, David J; Guiton, Beth S; Camden, Jon P

    2012-08-16

    Since the observation of single-molecule surface-enhanced Raman scattering (SMSERS) in 1997, questions regarding the nature of the electromagnetic hot spots responsible for such observations still persist. For the first time, we employ electron-energy-loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM) to obtain maps of the localized surface plasmon modes of SMSERS-active nanostructures, which are resolved in both space and energy. Single-molecule character is confirmed by the bianalyte approach using two isotopologues of Rhodamine 6G. Surprisingly, the STEM/EELS plasmon maps do not show any direct signature of an electromagnetic hot spot in the gaps between the nanoparticles. The origins of this observation are explored using a fully three-dimensional electrodynamics simulation of both the electron-energy-loss probability and the near-electric field enhancements. The calculations suggest that electron beam excitation of the hot spot is possible, but only when the electron beam is located outside of the junction region.

  10. N-type doping in CdO ceramics: a study by EELS and photoemission spectroscopy

    Science.gov (United States)

    Dou, Y.; Egdell, R. G.; Walker, T.; Law, D. S. L.; Beamson, G.

    1998-02-01

    Ceramic samples of yttrium- and indium-doped CdO ( Cd1 - xYxO with 0 ≤ x ≤ 0.035 and Cd1 - xInxO with 0 ≤ x ≤ 0.023) have been studied by electron energy loss spectroscopy (EELS) and ultraviolet and X-ray photoemission spectroscopy (UPS and XPS). Both In and Y act as efficient n-type dopants, although the carrier concentration is higher in In-doped material. The maximum surface plasmon loss energy in EELS is 0.66 eV in Y-doped samples and 0.72 eV for in-doped samples. Effective masses ( m∗) increase with increasing carrier concentration N and obey an approximately linear variation of the form m∗ = m ∗o + cN , where c is a constant. UPS shows a well-defined conduction band feature for doped samples. A shift of the valence band edge towards high binding energy due to chemical doping was observed in He(I) UPS, which is confirmed by shifts of O 2p valence band features and Cd 4d core level peaks in high resolution XPS. However, the shifts are less than expected from the increased widths of the occupied part of the conduction band. This is due to shrinkage of the bandgap with doping. XPS demonstrates that there is pronounced surface segregation of dopant atoms. However, the segregated dopant atoms do not act as donor centres.

  11. Analysis of polycrystalline SrRuO3 by TEM and EELS

    Science.gov (United States)

    Ito, Yasuo; Klamut, Piotr; Dabrowski, Bogdan; Maxwell, Mike

    2002-03-01

    Analysis of polycrystalline SrRuO3 by TEM and EELS Y. Ito, P. W. Klamut , B. Dabrowski, M. Maxwell Department of Physics, Northern Illinois University, DeKalb, IL Two polycrystalline SrRuO3 samples were prepared (1) in the conventional manner (Curie temperature TC = 165K) and (2) at high pressure of oxygen resulting in substantially lower TC (= 90K). The Mössbauer Ru (99) analysis of the sample (1) showed a unique hyperfine magnetic field and, corresponding to one Ru site (+4) and a broad single line above the TC (96K), indicating the presence of multiple sites and/or electric quadrupole interaction for the sample (2) [1]. Here, we investigate the microscopic origins of the above differences and the relationship between microstructure, composition, and electronic structure of these two polycrystalline SrRuO3 by using transmission electron microscopy and electron energy-loss spectroscopy (EELS). [1] M. DeMarco, P.W. Klamut, B. Dabrowski, S. Toorongian and M. Haka, see abstract of this meeting. Supported by NSF-DMR-0105398, and HECA.

  12. An electric-eel-inspired soft power source from stacked hydrogels

    Science.gov (United States)

    Schroeder, Thomas B. H.; Guha, Anirvan; Lamoureux, Aaron; Vanrenterghem, Gloria; Sept, David; Shtein, Max; Yang, Jerry; Mayer, Michael

    2017-12-01

    Progress towards the integration of technology into living organisms requires electrical power sources that are biocompatible, mechanically flexible, and able to harness the chemical energy available inside biological systems. Conventional batteries were not designed with these criteria in mind. The electric organ of the knifefish Electrophorus electricus (commonly known as the electric eel) is, however, an example of an electrical power source that operates within biological constraints while featuring power characteristics that include peak potential differences of 600 volts and currents of 1 ampere. Here we introduce an electric-eel-inspired power concept that uses gradients of ions between miniature polyacrylamide hydrogel compartments bounded by a repeating sequence of cation- and anion-selective hydrogel membranes. The system uses a scalable stacking or folding geometry that generates 110 volts at open circuit or 27 milliwatts per square metre per gel cell upon simultaneous, self-registered mechanical contact activation of thousands of gel compartments in series while circumventing power dissipation before contact. Unlike typical batteries, these systems are soft, flexible, transparent, and potentially biocompatible. These characteristics suggest that artificial electric organs could be used to power next-generation implant materials such as pacemakers, implantable sensors, or prosthetic devices in hybrids of living and non-living systems.

  13. Convergent evolution of jaws between spinosaurid dinosaurs and pike conger eels

    Directory of Open Access Journals (Sweden)

    Romain Vullo

    2016-12-01

    Full Text Available Spinosaurs represent a group of peculiar theropod dinosaurs that have often been described as “crocodile-mimic”, predominantly fish-eating predators, and recently claimed to have been semi-aquatic animals. Here we report a suite of craniodental characters unexpectedly shared by spinosaurs and pike conger eels. Pike conger eels are predatory, mainly piscivorous bottom-dwelling anguilliform fishes that inhabit marine and brackish environments. These two groups of dinosaurs and fishes show a mediolaterally compressed, elongated rostrum, a terminal “rosette” bearing enlarged teeth in both upper and lower jaws, and a notch posterior to the premaxillary “rosette” characterized by the presence of reduced teeth. The morphological convergence observed in the jaws of these two distantly related groups of vertebrates may result from similar feeding behaviours. This typical jaw morphology likely represents an effective biomechanical adaptation for biting and grabbing elusive prey items in low-light aquatic environments. Associated with this specialized snout morphology, numerous integumentary mechanoreceptors involved in prey detection are present in both spinosaurs and pike congers. Our new observations provide an additional convincing argument regarding the decades-long and widely debated lifestyle of spinosaurs.

  14. Measuring bandgap states in individual non-stoichiometric oxide nanoparticles using monochromated STEM EELS: The Praseodymium–ceria case

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, W.J. [School for the Engineering of Matter, Transport and Energy, Arizona State University, 501 E. Tyler Mall, Tempe, AZ 85287-6106 (United States); March, K. [Laboratoire de Physique des Solides, Université Paris-Sud, CNRS, UMR 8502, 91405 Orsay Cedex (France); Hernandez, C.A. [School for the Engineering of Matter, Transport and Energy, Arizona State University, 501 E. Tyler Mall, Tempe, AZ 85287-6106 (United States); Crozier, P.A., E-mail: crozier@asu.edu [School for the Engineering of Matter, Transport and Energy, Arizona State University, 501 E. Tyler Mall, Tempe, AZ 85287-6106 (United States)

    2016-08-15

    We describe a method to perform high spatial resolution measurement of the position and density of inter-band impurity states in non-stoichiometric oxides using ultra-high energy resolution electron energy-loss spectroscopy (EELS). This can be employed to study optical and electronic properties of atomic and nanoscale defects in electrically-conducting and optically-active oxides. We employ a monochromated scanning transmission electron microscope with subnanometer diameter electron probe, making this technique suitable for correlating spectroscopic information with high spatial resolution images from small objects such as nanoparticles, surfaces or interfaces. The specific experimental approach outlined here provides direct measurement of the Pr inter-band impurity states in Pr{sub 0.1}Ce{sub 0.9}O{sub 2−δ} via valence-loss EELS, which is interpreted with valence-loss spectral simulation based on density of states data to determine the energy level and character of the inter-band state. Additionally, observation of optical color change upon chemically-induced oxygen non-stoichiometry indicates that the population of the inter-band state is accompanied by an energy level shift within the bandgap. - Highlights: • Ultra-high energy resolution EELS used to study inter-band states in oxide. • Energy level and character of inter-band state determined from spectral model. • EELS coupled with optical color change indicates energy shift of inter-band state.

  15. Vigorous SO4(2-) influx via the gills is balanced by enhanced SO4(2-) excretion by the kidney in eels after seawater adaptation.

    Science.gov (United States)

    Watanabe, Taro; Takei, Yoshio

    2012-05-15

    Sulfate (SO(4)(2-)) is maintained at ∼1 mmol(-1) l(-1) in teleost fishes that are exposed to media of varying SO(4)(2-) concentrations. We first measured plasma SO(4)(2-) concentration in euryhaline fishes that adapt to both SO(4)(2-)-poor freshwater (freshwater (6.2±2.3 mmol l(-1)) than in seawater (0.7±0.1 mmol l(-1)). We then analyzed the whole-body SO(4)(2-) budget using (35)SO(4)(2-). (35)SO(4)(2-) influx in seawater-adapted eels occurred by 84.5% via body surfaces and 15.5% via digestive tracts. The SO(4)(2-) influx was higher in seawater eels (1.55 μmol kg(-1) h(-1)) than in freshwater eels (0.09 μmol kg(-1) min(-1)), but it was facilitated in freshwater eels when the difference in SO(4)(2-) concentrations between plasma and environment was taken into account (freshwater eels, 6.2 vs 0.3 mmol l(-1); seawater eels, 0.7 vs 30 mmol l(-1)). One hour after injection of (35)SO(4)(2-) into the blood of seawater eels, the kidney excreted ∼97% of the ionized form, whereas the radioactivity increased gradually in the medium and the rectal fluid more than 3 h after injection. As the radioactivity was poorly adsorbed by anion-exchange resin, (35)SO(4)(2-) in the blood may be incorporated into cells and excreted by the intestine, gills and skin, probably as mucus. These results show that freshwater eels take up SO(4)(2-) actively from the environment, but seawater eels cope with the obligatory influx of SO(4)(2-) through the gills by excreting excess SO(4)(2-) via the kidney and in mucus.

  16. Ammonia stress under high environmental ammonia induces Hsp70 and Hsp90 in the mud eel, Monopterus cuchia.

    Science.gov (United States)

    Hangzo, Hnunlalliani; Banerjee, Bodhisattwa; Saha, Shrabani; Saha, Nirmalendu

    2017-02-01

    The obligatory air-breathing mud eel (Monopterus cuchia) is frequently being challenged with high environmental ammonia (HEA) exposure in its natural habitats. The present study investigated the possible induction of heat shock protein 70 and 90 (hsp70, hsc70, hsp90α and hsp90β) genes and more expression of Hsp70 and Hsp90 proteins under ammonia stress in different tissues of the mud eel after exposure to HEA (50 mM NH4Cl) for 14 days. HEA resulted in significant accumulation of toxic ammonia in different body tissues and plasma, which was accompanied with the stimulation of oxidative stress in the mud eel as evidenced by more accumulation of malondialdehyde (MDA) and hydrogen peroxide (H2O2) during exposure to HEA. Further, hyper-ammonia stress led to significant increase in the levels of mRNA transcripts for inducible hsp70 and hsp90α genes and also their translated proteins in different tissues probably as a consequence of induction of hsp70 and hsp90α genes in the mud eel. However, hyper-ammonia stress was neither associated with any significant alterations in the levels of mRNA transcripts for constitutive hsc70 and hsp90β genes nor their translated proteins in any of the tissues studied. More abundance of Hsp70 and Hsp90α proteins might be one of the strategies adopted by the mud eel to defend itself from the ammonia-induced cellular damages under ammonia stress. Further, this is the first report of ammonia-induced induction of hsp70 and hsp90α genes under hyper-ammonia stress in any freshwater air-breathing teleost.

  17. Adaptive Evolution of Eel Fluorescent Proteins from Fatty Acid Binding Proteins Produces Bright Fluorescence in the Marine Environment

    Science.gov (United States)

    Gruber, David F.; Gaffney, Jean P.; Mehr, Shaadi; DeSalle, Rob; Sparks, John S.; Platisa, Jelena; Pieribone, Vincent A.

    2015-01-01

    We report the identification and characterization of two new members of a family of bilirubin-inducible fluorescent proteins (FPs) from marine chlopsid eels and demonstrate a key region of the sequence that serves as an evolutionary switch from non-fluorescent to fluorescent fatty acid-binding proteins (FABPs). Using transcriptomic analysis of two species of brightly fluorescent Kaupichthys eels (Kaupichthys hyoproroides and Kaupichthys n. sp.), two new FPs were identified, cloned and characterized (Chlopsid FP I and Chlopsid FP II). We then performed phylogenetic analysis on 210 FABPs, spanning 16 vertebrate orders, and including 163 vertebrate taxa. We show that the fluorescent FPs diverged as a protein family and are the sister group to brain FABPs. Our results indicate that the evolution of this family involved at least three gene duplication events. We show that fluorescent FABPs possess a unique, conserved tripeptide Gly-Pro-Pro sequence motif, which is not found in non-fluorescent fatty acid binding proteins. This motif arose from a duplication event of the FABP brain isoforms and was under strong purifying selection, leading to the classification of this new FP family. Residues adjacent to the motif are under strong positive selection, suggesting a further refinement of the eel protein’s fluorescent properties. We present a phylogenetic reconstruction of this emerging FP family and describe additional fluorescent FABP members from groups of distantly related eels. The elucidation of this class of fish FPs with diverse properties provides new templates for the development of protein-based fluorescent tools. The evolutionary adaptation from fatty acid-binding proteins to fluorescent fatty acid-binding proteins raises intrigue as to the functional role of bright green fluorescence in this cryptic genus of reclusive eels that inhabit a blue, nearly monochromatic, marine environment. PMID:26561348

  18. Adaptive Evolution of Eel Fluorescent Proteins from Fatty Acid Binding Proteins Produces Bright Fluorescence in the Marine Environment.

    Directory of Open Access Journals (Sweden)

    David F Gruber

    Full Text Available We report the identification and characterization of two new members of a family of bilirubin-inducible fluorescent proteins (FPs from marine chlopsid eels and demonstrate a key region of the sequence that serves as an evolutionary switch from non-fluorescent to fluorescent fatty acid-binding proteins (FABPs. Using transcriptomic analysis of two species of brightly fluorescent Kaupichthys eels (Kaupichthys hyoproroides and Kaupichthys n. sp., two new FPs were identified, cloned and characterized (Chlopsid FP I and Chlopsid FP II. We then performed phylogenetic analysis on 210 FABPs, spanning 16 vertebrate orders, and including 163 vertebrate taxa. We show that the fluorescent FPs diverged as a protein family and are the sister group to brain FABPs. Our results indicate that the evolution of this family involved at least three gene duplication events. We show that fluorescent FABPs possess a unique, conserved tripeptide Gly-Pro-Pro sequence motif, which is not found in non-fluorescent fatty acid binding proteins. This motif arose from a duplication event of the FABP brain isoforms and was under strong purifying selection, leading to the classification of this new FP family. Residues adjacent to the motif are under strong positive selection, suggesting a further refinement of the eel protein's fluorescent properties. We present a phylogenetic reconstruction of this emerging FP family and describe additional fluorescent FABP members from groups of distantly related eels. The elucidation of this class of fish FPs with diverse properties provides new templates for the development of protein-based fluorescent tools. The evolutionary adaptation from fatty acid-binding proteins to fluorescent fatty acid-binding proteins raises intrigue as to the functional role of bright green fluorescence in this cryptic genus of reclusive eels that inhabit a blue, nearly monochromatic, marine environment.

  19. European communion

    DEFF Research Database (Denmark)

    Manners, Ian James

    2013-01-01

    Political theory of European union, through an engagement between political concepts and theoretical understandings, provides a means of identifying the EU as a political object. It is argued that understanding the projects, processes and products of European union, based on ‘sharing’ or ‘communion......’, provides a better means of perceiving the EU as a political object rather than terms such as ‘integration’ or ‘co-operation’. The concept of ‘European communion’ is defined as the ‘subjective sharing of relationships’, understood as the extent to which individuals or groups believe themselves to be sharing...... relations (or not), and the consequences of these beliefs for European political projects, processes and products. By exploring European communion through an engagement with contemporary political theory, using very brief illustrations from the Treaty of Lisbon, the article also suggests that European...

  20. European Institutions?

    NARCIS (Netherlands)

    Meacham, Darian

    2016-01-01

    The aim of this article is to sketch a phenomenological theory of political institutions and to apply it to some objections and questions raised by Pierre Manent about the project of the European Union and more specifically the question of “European Construction”, i.e. what is the aim of the

  1. Selective Europeanization

    DEFF Research Database (Denmark)

    Hoch Jovanovic, Tamara; Lynggaard, Kennet

    2014-01-01

    political contexts at the European level. We further show how the “translation” of international norms to a domestic context has worked to reinforce the original institutional setup, dating back to the mid-1950s. The translation of European-level minority policy developed in the 1990s and 2000s works most...

  2. Flood inundation maps for the Wabash and Eel Rivers at Logansport, Indiana

    Science.gov (United States)

    Fowler, Kathleen K.

    2014-01-01

    Digital flood-inundation maps for an 8.3-mile reach of the Wabash River and a 7.6-mile reach of the Eel River at Logansport, Indiana (Ind.), were created by the U.S. Geological Survey (USGS) in cooperation with the Indiana Office of Community and Rural Affairs. The inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at USGS streamgage Wabash River at Logansport, Ind. (sta. no. 03329000) and USGS streamgage Eel River near Logansport, Ind. (sta. no. 03328500). Current conditions for estimating near-real-time areas of inundation using USGS streamgage information may be obtained on the Internet at http://waterdata.usgs.gov/. In addition, information has been provided to the National Weather Service (NWS) for incorporation into their Advanced Hydrologic Prediction Service (AHPS) flood warning system http:/water.weather.gov/ahps/). The NWS forecasts flood hydrographs at many places that are often colocated with USGS streamgages. NWS-forecasted peak-stage information may be used in conjunction with the maps developed in this study to show predicted areas of flood inundation. For this study, flood profiles were computed for the stream reaches by means of a one-dimensional step-backwater model developed by the U.S. Army Corps of Engineers. The hydraulic model was calibrated by using the most current stage-discharge relations at USGS streamgages 03329000, Wabash River at Logansport, Ind., and 03328500, Eel River near Logansport, Ind. The calibrated hydraulic model was then used to determine five water-surface profiles for flood stage at 1-foot intervals referenced to the Wabash River streamgage datum, and four water-surface profiles for flood stages at 1-foot intervals referenced to the Eel River streamgage datum. The stages range from bankfull to approximately the highest

  3. Scaling of the Surface Plasmon Resonance in Gold and Silver Dimers Probed by EELS

    DEFF Research Database (Denmark)

    Kadkhodazadeh, Shima; de Lasson, Jakob Rosenkrantz; Beleggia, Marco

    2014-01-01

    . Instead, within the range 0.1R determined for both gold and silver dimers. Despite this common power dependence, consistently larger SPR wavelength shifts are registered for silver for a given change in d, implying......The dependence of surface plasmon coupling on the distance between two nanoparticles (dimer) is the basis of nanometrology tools such as plasmon rulers. Application of these nanometric rulers requires an accurate description of the scaling of the surface plasmon resonance (SPR) wavelength...... with distance. Here, we have applied electron energy-loss spectroscopy (EELS) and scanning transmission electron microscopy (STEM) imaging to investigate the relationship between the SPR wavelength of gold and silver nanosphere dimers (radius R) and interparticle distance (d) in the range 0.1R

  4. Growth promoting effect of hyaluronan synthesis promoting substances on Japanese eel leptocephali.

    Directory of Open Access Journals (Sweden)

    Yutaka Kawakami

    Full Text Available Hyaluronans (HAs are glycosaminoglycans produced in the bodies of Anguilliform and Elopiform leptocephali, and play a role in metabolic energy. In mammals, HA synthesis-promoting substances (HASPS up-regulate the expression of HA synthase (HAS and increase the amount of HA in the body. In this study, Japanese eel leptocephali were fed a HASPS containing diet. We analyzed HAS1s and HAS2 expression, HA content, and their influence on growth. HASPS extracted from Grifola frondosa promoted HAS1s and HAS2 mRNA and HA content. Other than mammals, these results are first reported in vertebrate. Moreover, HASPS extracted from G. frondosa promoted leptocephalus growth. The relationship between growth and HA in the leptocephali is not yet clear. However, based on our results we hypothesize that HA is involved in the storage of energy, which is metabolized to sugars when needed for metabolic energy.

  5. Growth Promoting Effect of Hyaluronan Synthesis Promoting Substances on Japanese Eel Leptocephali

    Science.gov (United States)

    Kawakami, Yutaka; Nomura, Kazuharu; Tanaka, Hideki

    2014-01-01

    Hyaluronans (HAs) are glycosaminoglycans produced in the bodies of Anguilliform and Elopiform leptocephali, and play a role in metabolic energy. In mammals, HA synthesis-promoting substances (HASPS) up-regulate the expression of HA synthase (HAS) and increase the amount of HA in the body. In this study, Japanese eel leptocephali were fed a HASPS containing diet. We analyzed HAS1s and HAS2 expression, HA content, and their influence on growth. HASPS extracted from Grifola frondosa promoted HAS1s and HAS2 mRNA and HA content. Other than mammals, these results are first reported in vertebrate. Moreover, HASPS extracted from G. frondosa promoted leptocephalus growth. The relationship between growth and HA in the leptocephali is not yet clear. However, based on our results we hypothesize that HA is involved in the storage of energy, which is metabolized to sugars when needed for metabolic energy. PMID:24896609

  6. SRY-related genes in the genome of the rice field eel (Monopterus albus

    Directory of Open Access Journals (Sweden)

    Cooper Richard K

    2002-01-01

    Full Text Available Abstract The mammalian sex determining gene, SRY, is the founding member of the new growing family of Sox (SRY-like HMG-box gene genes. Sox genes encode transcription factors with diverse roles in development, and a few of them are involved in sex determination and differentiation. We report here the existence of Sox genes in the rice field eel, Monopterus albus, and DNA sequence information of the HMG box region of five Sox genes. The Sox1, Sox4 and Sox14 genes do not have introns in the HMG box region. The Sox9 gene and Sox17 gene, which each have an intron in the conserved region, show strong identity at the amino acid level with the corresponding genes of mammals and chickens. Similar structure and identity of the Sox9 and Sox17 genes among mammals, chickens and fish suggest that these genes have evolutionarily conserved roles, potentially including sex determination and differentiation.

  7. Proteomic analysis of three gonad types of swamp eel reveals genes differentially expressed during sex reversal.

    Science.gov (United States)

    Sheng, Yue; Zhao, Wei; Song, Ying; Li, Zhigang; Luo, Majing; Lei, Quan; Cheng, Hanhua; Zhou, Rongjia

    2015-05-18

    A variety of mechanisms are engaged in sex determination in vertebrates. The teleost fish swamp eel undergoes sex reversal naturally and is an ideal model for vertebrate sexual development. However, the importance of proteome-wide scanning for gonad reversal was not previously determined. We report a 2-D electrophoresis analysis of three gonad types of proteomes during sex reversal. MS/MS analysis revealed a group of differentially expressed proteins during ovary to ovotestis to testis transformation. Cbx3 is up-regulated during gonad reversal and is likely to have a role in spermatogenesis. Rab37 is down-regulated during the reversal and is mainly associated with oogenesis. Both Cbx3 and Rab37 are linked up in a protein network. These datasets in gonadal proteomes provide a new resource for further studies in gonadal development.

  8. Salinity tolerance of non-native Asian swamp eels (Teleostei: Synbranchidae) in Florida, USA: Comparison of three populations and implications for dispersal

    Science.gov (United States)

    Schofield, P.J.; Nico, L.G.

    2009-01-01

    Three populations of non-native Asian swamp eels are established in peninsular Florida (USA), and comprise two different genetic lineages. To assess potential for these fish to penetrate estuarine habitats or use coastal waters as dispersal routes, we determined their salinity tolerances. Swamp eels from the three Florida populations were tested by gradual (chronic) salinity increases; additionally, individuals from the Miami population were tested by abrupt (acute) salinity increases. Results showed significant tolerance by all populations to mesohaline waters: Mean survival time at 14 ppt was 63 days. The Homestead population, a genetically distinct lineage, exhibited greater tolerance to higher salinity than Tampa and Miami populations. Acute experiments indicated that swamp eels were capable of tolerating abrupt shifts from 0 to 16 ppt, with little mortality over 10 days. The broad salinity tolerance demonstrated by these experiments provides evidence that swamp eels are physiologically capable of infiltrating estuarine environments and using coastal waters to invade new freshwater systems. ?? 2009 US Government.

  9. Construction and analysis of gonad suppression subtractive hybridization libraries for the rice field eel, Monopterus albus.

    Science.gov (United States)

    Qu, Xiancheng; Jiang, Jiaoyun; Shang, Xiaoli; Cheng, Cui; Feng, Long; Liu, Qigen

    2014-04-25

    The objective of this study was to investigate gene transcription profiles of the stage IV ovary and the ovotestis of the rice field eel (Monopterus albus) in an attempt to uncover genes involved in sex reversal and gonad development. Suppression subtractive hybridization (SSH) libraries were constructed using mRNA from the stage IV ovary and the ovotestis. In total 100 positive clones from the libraries were selected at random and sequenced, and then expressed sequence tags (ESTs) were used to search against sequences in the GenBank database using the BLASTn and BLASTx search algorithms. High quality SSH cDNA libraries and 90 ESTs were obtained. Of these ESTs, 43 showed high homology with genes of known function and these are associated with energy metabolism, signal transduction, transcription regulation and so on. The remaining 47 ESTs shared no homology with any genes in GenBank and are thus considered to be hypothetical genes. Furthermore, the four genes F11, F63, R11, and R47 from the forward and reverse libraries were analyzed in gonad, brain, heart, spleen, liver, kidney and muscle tissues. The results showed that the transcription of the F11 and F63 genes was significantly increased while the expression of the R11 and R47 genes was significantly decreased from IV or V ovary. In addition, the results also indicated that the four genes' expression was not gonad-tissue specific. This results strongly suggested that they may be involved in the rice field eel gonad development and/or sex reversal. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. European Whiteness?

    DEFF Research Database (Denmark)

    Blaagaard, Bolette

    2008-01-01

    Born out of the United States’ (U.S.) history of slavery and segregation and intertwined with gender studies and feminism, the field of critical whiteness studies does not fit easily into a European setting and the particular historical context that entails. In order for a field of European...... critical whiteness studies to emerge, its relation to the U.S. theoretical framework, as well as the particularities of the European context need to be taken into account.. The article makes a call for a multi-layered approach to take over from the identity politics so often employed in the fields of U...

  11. Characterization of Nb Superconducting Radio Frequency Cavities Based On In-Situ STEM And EELS

    Science.gov (United States)

    Tao, Runzhe

    Niobium, a 4d transition metal, has the highest superconducting transition temperature (Tc=9.2K) of any elemental superconductor as type II superconductor with coherent length, sigma approximately that of the penetration length, lambda. Pure niobium is grey in color and very soft, which makes this metal easily fabricable into different shapes for superconducting radio- frequency (SRF) cavities. Such cavities are used in some modern accelerators (SNS, CEBAF, XFEL), and are intended for usage in the next generation of particle accelerators, such as ILC. Since the crucial part of the cavities is top 100 nm of Nb near the inner cavity surface, considering the penetration depth is around 40 nm, it has attracted more and more attention in improving the surface process for optimizing the performance of the cavities. Nowadays, the main treatment of the Nb surface includes electro polishing (EP), buffered chemical polishing (BCP), high temperature baking (800 °C, 1000 °C and 1200 °C) and mild baking (120 °C). Firstly, the two half cells are welded together and the weld line is quite rough; there exists a lot of visible pits and defects on the inner shell of cavities. In this Ph.D. thesis, novel techniques in a scanning transmission electron microscope (STEM) that can be used to analyze the atomic scale structure-property relationship, both at room tem- perature and high/LN 2 temperature, are explored. Specifically, by using correlated Z-contrast imaging and electron energy loss spectrum (EELS), the structure, composition and bonding can be characterized directly on the atomic scale, also, light atoms, like H, O and C, are visible in ABF images. For the examining the defect behavior on the cavity surface, heating and cold stages are involved to simulate the baking treatment and low-temperature environments. These studies will serve as an important reference for qualifying different surface treatments to further improve SRF cavities' performance. The experimental results

  12. European Security

    DEFF Research Database (Denmark)

    Møller, Bjørn

    Theoretical chapters on "Security", "Organisations" and "Regions," Historical Chapters on "Europe and Its Distinguishing Features" and on "The United Nations," "NATO," "The CSCE/OSCE and the Council of Europe" and "The European Union"......Theoretical chapters on "Security", "Organisations" and "Regions," Historical Chapters on "Europe and Its Distinguishing Features" and on "The United Nations," "NATO," "The CSCE/OSCE and the Council of Europe" and "The European Union"...

  13. Roles of the cytoskeleton and of Protein Phosphorylation Events in the Osmotic Stress Response in EEL Intestinal Epithelium

    DEFF Research Database (Denmark)

    Lionetto, Maria G; Pedersen, Stine F; Hoffmann, Else K

    2002-01-01

    /threonine phosphorylation events in the osmotic stress-induced ion transport in the eel intestinal epithelium, focusing on the sustained RVI phase, as well as on the previously uncharacterized response to hypotonic stress. The study was carried out using confocal laser scanning microscopy, a quantitative F-actin assay......, and transepithelial electrophysiological measurements (V(te) and Isc) in Ussing chambers. Hypertonic stress did not detectably alter either net F-actin content or F-actin organization. In contrast, a brief exposure to hypotonic stress decreased the total cellular F-actin content in eel intestinal epithelium by about......) inhibitor chelerythrine, the myosin light chain kinase (MLCK) inhibitor ML-7, or the serine/threonine protein phosphatase inhibitor Calyculin A, but was unaffected by the PKA inhibitor H-89. The electrophysiological response of the epithelium to hypotonic stress was characterized by a sustained decrease...

  14. Surface chemistry of n-octane modified silicon nanoparticles analyzed by IR, 13C CPMAS NMR, EELS, and TGA.

    Science.gov (United States)

    Nelles, Jürgen; Sendor, Dorota; Bertmer, Marko; Ebbers, André; Petrat, Frank-Martin; Simon, Ulrich

    2007-08-01

    The functionalization of silicon nanoparticles by thermally induced hydrosilylation in a one-pot process is reported. In contrast to the commonly applied thermally induced hydrosilylation, the process described here is carried out in the presence of hydrofluoric acid as a second phase and therefore proceeds at a lower conversion temperature. The surface functionalization of silicon nanoparticles was analyzed by IR, 13C CPMAS NMR, EELS, and TGA techniques. The applied procedure resulted in functionalized silicon nanoparticles with good chemical and thermal stability.

  15. European visit

    CERN Multimedia

    2006-01-01

    The European Commissioner for Science and Research, Janez Potočnik, (on the right) visited the CMS assembly hall accompanied by Jim Virdee, Deputy Spokesman of CMS (on the left), and Robert Aymar, Director-General of CERN. The European Commissioner for Science and Research, Janez Potočnik, visited CERN on Tuesday 31 January. He was welcomed by the Director-General, Robert Aymar, who described the missions and current activities of CERN to him, in particular the realisation of the LHC with its three components: accelerator, detectors, storage and processing of data. The European Commissioner then visited the CMS assembly hall, then the hall for testing the LHC magnets and the ATLAS cavern. During this first visit since his appointment at the end of 2004, Janez Potočnik appeared very interested by the operation of CERN, an example of successful scientific co-operation on a European scale. The many projects (30 on average) that CERN and the European Commission carry out jointly for the benefit of res...

  16. Optical properties of Group X-XII intermetallic compounds studied by HR-EELS.

    Science.gov (United States)

    Sato, Yohei; Terauchi, Masami; Kameoka, Satoshi; Tsai, An-Pang

    2014-11-01

    Electronic structure of d orbital states in transition metals is a key factor for their physical properties and chemical functions. Copper and intermetallic compound PdZn have good catalysis function for the methanol steam reforming reaction. Tsai et al. showed that from results of XPS measurements the d electronic structure of PdZn was similar with that of copper, and the catalysis function should be related to the d electron states [1]. This similarity of d electronic states leads to another view point of the mechanism for coloring the intermetallic compounds. It is well-known that the characteristic red color of copper is caused by interband transition from the d electrons. Therefore, PdZn and Group X-XII intermetallic compounds are expected to be colored and the optical properties should depend on the d electronic states. In this study, the relations between optical properties and d electron states of Group X-XII intermetallic compounds were investigated by using high energy-resolution electron energy-loss spectroscopy (HR-EELS) based on transmission electron microscopy (TEM). From the relation between optical properties and d electronic states, the mechanism of colored intermetallic compounds will be discussed.Figure shows the optical reflectivity of NiZn, PdZn and PtZn, which were derived from EELS spectra by Kramers-Kronig analysis. Intensity drops (arrows) of the reflectivity were observed in visible energy region. These are caused by the interband transitions from d electronic states. The energy positions of the reflectivity drops have tendency of shifting to higher energy side with increasing atomic number of Group X elements (Ni → Pd → Pt). This indicates that the transition energies of d electrons become larger with the atomic number of the elements. First principle calculations (WIEN2k) confirmed that the interband transitions of d electronic states were excitations from bonding d states to hybrid states of anti-bonding s, p, and d states of Group

  17. Thickness dependence of Electron Energy Loss Spectra (EELS) of MoS2 films

    Science.gov (United States)

    Xue, Feng; Yan, Xinxu; Wang, Zhe; Wang, Hui; Pan, Xiaoqing; Wu, Ruqian

    Band structures and optical properties of monolayer, bilayer, and bulk MoS2 are studied using the GW approximation in conjunction with the Bethe-Salpeter equation (BSE). The calculated electron energy loss spectra (EELS) of these systems show peak structures that depend on the thickness. In particular, the pronounced peak near 3 eV moves to lower energy with the increasing of film thickness. Through analysis of transition matrices and density of states, we attribute this peak shift to modifications of the band structures through the weak interlayer van der Waals interaction. Comparison between theory and experiment are made to reveal the physical insights and to provide guidance for the utilization of novel two-dimensional materials. Work at Fudan was supported by the Chinese National Science Foundation (Grant No. 11474056) and National Basic Research Program of China (Grant No. 2015CB921400). Work at UCI was supported by DOE-BES (Grant No. DE-FG02-05ER46237).

  18. In Situ STEM-EELS Observation of Nanoscale Interfacial Phenomena in All-Solid-State Batteries.

    Science.gov (United States)

    Wang, Ziying; Santhanagopalan, Dhamodaran; Zhang, Wei; Wang, Feng; Xin, Huolin L; He, Kai; Li, Juchuan; Dudney, Nancy; Meng, Ying Shirley

    2016-06-08

    Behaviors of functional interfaces are crucial factors in the performance and safety of energy storage and conversion devices. Indeed, solid electrode-solid electrolyte interfacial impedance is now considered the main limiting factor in all-solid-state batteries rather than low ionic conductivity of the solid electrolyte. Here, we present a new approach to conducting in situ scanning transmission electron microscopy (STEM) coupled with electron energy loss spectroscopy (EELS) in order to uncover the unique interfacial phenomena related to lithium ion transport and its corresponding charge transfer. Our approach allowed quantitative spectroscopic characterization of a galvanostatically biased electrochemical system under in situ conditions. Using a LiCoO2/LiPON/Si thin film battery, an unexpected structurally disordered interfacial layer between LiCoO2 cathode and LiPON electrolyte was discovered to be inherent to this interface without cycling. During in situ charging, spectroscopic characterization revealed that this interfacial layer evolved to form highly oxidized Co ions species along with lithium oxide and lithium peroxide species. These findings suggest that the mechanism of interfacial impedance at the LiCoO2/LiPON interface is caused by chemical changes rather than space charge effects. Insights gained from this technique will shed light on important challenges of interfaces in all-solid-state energy storage and conversion systems and facilitate improved engineering of devices operated far from equilibrium.

  19. Monticellia ophisterni n. sp. (Cestoda: Monticelliidae) from the swamp-eel Ophisternon aenigmaticum (Synbranchiformes) from Mexico.

    Science.gov (United States)

    Scholz, T; de Chambrier, A; Salgado-Maldonado, G

    2001-12-01

    Monticellia ophisterni n. sp. is described from the swamp-eel Ophisternon aenigmaticum Rosen and Greenwood (Synbranchiformes: Synbranchidae) from Lake Catemaco, Veracruz, Mexico. The new species is placed into Monticellia because of the cortical position of the testes, ovary, and uterus. It differs from other Monticellia species (with the exception of Monticellia magna (Rego, Santos and Silva, 1974)) in the position of longitudinal musculature that crosses the vitelline follicles, making them paramuscular. The new species can be distinguished from M. magna--which possesses a similar number of testes (107-139), paramuscular vitelline follicles, and numerous gland cells distributed between the apex of the scolex and suckers--in the position of the genital pore (8-21% vs. 19-27%), in the presence of a weak internal longitudinal musculature, in the arrangement of the testes in the median field, and in the absence of a vaginal sphincter. This is the first proteocephalidean tapeworm reported from a synbranchid fish and the first species of Monticellia found in North America.

  20. Kinematics of terrestrial capture of prey by the eel-catfish Channallabes apus.

    Science.gov (United States)

    Van Wassenbergh, Sam

    2013-08-01

    In contrast to numerous studies on the function of the locomotor system used by fishes when moving between water and land, little knowledge is available about the biomechanical requirements to the capture and transport of food by fish in a terrestrial situation. This study focuses on the kinematics of terrestrial capture of prey by the eel-catfish (Channallabes apus: Clariidae), a behavior that was only recently discovered for this species. The analyses show that C. apus inclines its head downward at a significantly steeper angle during terrestrial feeding compared with benthic aquatic feeding. This suggests that placing the jaws above ground-based prey is important for successful prehension by the jaws. The increased inclination of the head resulted from accumulated dorsoventral flexion of the body more than one head-length behind the skull. Alternatively, this posture of the head was assumed by rolling to one side while bending the body laterally. The speed of buccopharyngeal expansion in air versus in water matched the predicted increase by a factor of 3, under the assumption that the velocity of muscular contraction for maximal output of power by C. apus is optimized to operate under a specific hydrodynamic loading, and shifts to an unloaded contraction regime when operating in air. Combining these insights with future studies on other extant amphibious fish species that perform terrestrial feeding may eventually allow us to pinpoint the adaptations to the feeding system that have led to the evolution of a terrestrial lifestyle in tetrapods.

  1. European Cinema

    NARCIS (Netherlands)

    Elsaesser, Thomas

    2005-01-01

    In the face of renewed competition from Hollywood since the early 1980s and the challenges posed to Europe's national cinemas by the fall of the Wall in 1989, independent filmmaking in Europe has begun to re-invent itself. European Cinema: Face to Face with Hollywood re-assesses the different

  2. Integrating habitat restoration and fisheries management : A small-scale case-study to support EEL conservation at the global scale

    Directory of Open Access Journals (Sweden)

    Ciccotti E.

    2013-02-01

    Full Text Available The aim of this work was to develop a methodological framework for the management of local eel stocks that integrates habitat restoration with optimal fishery management. The Bolsena lake (Viterbo, Italy and its emissary, the river Marta, were taken as a reference system. The river flows in the Mediterranean sea but its course is fragmented by a number of dams built in the past century preventing eel migration from and to the sea. Eel fishery in the Bolsena lake is thus sustained by periodic stocking of glass eels caught at the Marta river estuary. A detailed demographic model was applied to simulate fishery yields and potential spawner escapement under different recruitment and management scenarios. It was estimated that the high exploitation rates occurring in the nineties reduced the potential spawner escapement from the Bolsena lake to less than 1 t; under current harvesting rates, the potential spawner escapement is estimated in about 12 t while in pristine conditions (i.e. high recruitment and no fishing estimated spawner escapement is about 21 t. This analysis thus showed that current fishery management would comply with the 40% spawner escapement requirement of the EU regulation 1100/2007 if the connections between the Bolsena lake emissary and the sea were fully re-established. This confirms the opportunity of an integrated approach to management at the catchment area level scale for eel populations, that shall hopefully contribute to the conservation of the global stock.

  3. Interactions between fisheries and birds in IJsselmeer, The Netherlands

    NARCIS (Netherlands)

    Mous, P.J.

    2000-01-01

    IJsselmeer, a eutrophic, shallow lake (mean depth 4 m) of 180,000 ha, is heavily exploited by a fishery that catches dfl 11 million worth of eel Anguilla anguilla , perch Perca fluviatilis , pikeperch Stizostedion lucioperca and

  4. Biological and technological effects of some mulberry varieties and ...

    African Journals Online (AJOL)

    egyptian hak

    Ecotoxicology & Environmental Safety 60: 193-. 197. Peignoux-Deville J, Lopez E, Lallier F, Bagot EM & Milet C (1975) Responses of ultimobranchial body in eels. (Anguilla anguilla L.) maintained in seawater and experimentally matured to injections of synthetic salmon calcitonin. Cell & Tissue Research 164: 73-83.

  5. Effects of exotic amphipod invasions on fish diet in the Lower Rhine

    NARCIS (Netherlands)

    Kelleher, B.; Bergers, P.J.M.; Brink, van den F.W.B.; Giller, P.S.; Velde, van der G.; Vaate, bij de B.

    1998-01-01

    To assess the importance and effect of recent exotic species invasions on components of food webs of common Lower Rhine biotopes (breakwaters and channel-connected sandpits), the diets of two important macrozoobenthivores, perch (Perca fluviatilis L.) and eel (Anguilla anguilla (L.)) were compared

  6. Idealized Modeling of the Extent and Stability of Cold Water Refugia at the Confluences of the South Fork of the Eel River

    Science.gov (United States)

    Greer, G.; Thompson, S. E.

    2016-12-01

    Heat stress threatens the summer survival of several fish species in the Western United states, and is likely to be exacerbated by anthropogenic climate and land use changes. Populations of cold-water dependent Pacific salmon in California are believed to depend on the presence of cold-water refugia, including refugia formed at the confluence of cold tributaries with warm main stem river channels. Identifying the location, extent, thermal regimes, and persistence of such refugia, as climate and catchment land uses change, is essential to predicting the thermal risks posed to Pacific salmon populations and identifying conservation priorities. The detailed statistical models currently used to identifying cold-water refugia are of uncertain value under non-stationary conditions, whose effects on thermal refugia may be better represented by mechanistic models derived from the physics of water flow and energy exchange. Such mechanistic models, however, are typically solved at the scale of an individual confluence, and are numerically and practically difficult to apply at the scale of an entire river basin. In this research project, we focus on the behavior of cold-water refugia in the South Fork Eel River (SF Eel) in Northern California. We adopt an idealized model to identify the effects of varying flow, fluvial geomorphology, and thermal regimes on the spatial extent of the cold-water refugia formed at the confluences of cold-water tributaries with the SF Eel main stem. Results are compared to in situ temperature data collected at the confluences of the SF Eel and Elder Creek and the SF Eel and Cedar Creek. The scaling relationships identified by the idealized model are suitable for coupling with basin-scale flow and temperature models to estimate the extent, temperature and persistence of cold-zones throughout the SF Eel, allowing the extent and sensitivity of cold-water refugia to be mapped at network-scales.

  7. New observations on the Middle Fork Eel River coal-bearing beds, Mendocino County, California, USA

    Energy Technology Data Exchange (ETDEWEB)

    Bartley, Russell H. [Mendocino County Museum, 400 East Commercial Street, Willits, CA 95490 (United States); Bartley, Sylvia E. [Noyo Hill House, 28953 Highway 20, Fort Bragg, CA 95437 (United States); Springer, David J. [College of the Redwoods-Mendocino Coast, 1211 Del Mar Drive, Fort Bragg, CA 95437 (United States); Erwin, Diane M. [Museum of Paleontology, 1101 Valley Life Sciences Building, University of California, Berkeley, CA 94720 (United States)

    2010-08-01

    Mid-19th century reports of ''immense'' coal outcrops in the Middle Fork Eel River (MFER) drainage near Round Valley in California's northern Coast Ranges fueled the early geological interest in this area, with mine development the primary focus of many studies. It was not until Samuel G. Clark's 1940 ''Geology of the Covelo District, Mendocino County, California,'' that the coal was placed in its regional geologic context and assigned to the Miocene, a determination that relied primarily on a Desmostylus hesperus molar found in shale overlying the coal and an associated equivocal, though Miocene-compatible, marine molluscan fauna. Our investigation of the MFER coal-bearing beds has provided new data from foraminifera, marine mollusks, fish remains, and the first reported fossil plants, which as a whole support Clark's Miocene age assignment. We also present an updated stratigraphy proposing under modern-day stratigraphic protocols that the informal name Sand Bank beds (SBb) be used in place of the Temblor Formation to refer to the SBb coal-bearing fluvial-marine unit. Analysis of the SBb stratigraphy and sedimentology reveals the presence of a fluvial system that flowed from a distal upland region southward toward the paleocoast of California. An abundant diverse palynoflora containing lycophytes, ferns, conifers, and mesic, thermophillic herbaceous and woody angiosperms indicates the drainage flowed through a coastal swampy forested bottomland and estuarine environment before emptying into a coastal basin. Presence of Taxodium-like wood, foliage, pollen, and other ''hydrophiles'' suggests the MFER coal was a local mire buried by the progradation of the SBb fluvial system during a regressive phase, an interpretation to be tested with future field work and detailed compositional analysis of the coal. (author)

  8. Spectrum imaging of complex nanostructures using DualEELS: II. Absolute quantification using standards.

    Science.gov (United States)

    Craven, Alan J; Sala, Bianca; Bobynko, Joanna; MacLaren, Ian

    2017-12-13

    Nanometre-sized TixV(1-x)CyNz precipitates in an Fe20%Mn steel matrix with a thickness range from 14 to 40 nm are analysed using DualEELS. Their thicknesses, volumes and compositions are quantified using experimental binary standards and the process used to give robust results is described. Precisions of a few percent are achieved with accuracies that are estimated to be of a similar magnitude. Sensitivities are shown to be at 0.5-1 unit cells range in the thinnest matrix region, based on the assumption that a sub-lattice is fully populated by the element. It rises to the 1-2 unit cell range for the metals and 2-3 unit cells for the non-metal in the thickest matrix region. The sensitivities for Ti and N are greater than those for V and C respectively because the O K-edge from surface oxide needs to be separated from the V L2,3-edge, and the C K-edges from C in the matrix and amorphous C on the surface have to be separated from the C in the precipitate itself. Separation of the contributions from the bulk and the surface is demonstrated, showing that there is significant and detectable C in the matrix but no O, while there is significant O but little C in the surface oxide. Whilst applied to precipitates in steel in this work, the approach can be adapted to many multi-phase systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Peracreadium akenovae sp. nov. (Trematoda: Opecoelidae) parasitising the highfin moray eel Gymnothorax pseudothyrsoideus (Anguilliformes: Muraenidae) from Moreton Bay, Australia.

    Science.gov (United States)

    Cribb, Thomas H; Bray, Rodney A; Cutmore, Scott C

    2013-09-01

    A new opecoelid trematode, Peracreadium akenovae sp. nov., is described from the highfin moray eel Gymnothorax pseudothyrsoideus (Bleeker) (Anguilliformes; Muraenidae), collected from Moreton Bay off southeast Queensland, Australia. The new species is distinctive in its body shape, transversely elongate irregular testes, vitelline follicles interrupted at the level of the ventral sucker, and diverticulate excretory vesicle. The Muraenidae is a new host family for Peracreadium Nicoll, 1909. Peracreadium is the seventh opecoelid genus reported from temperate eastern Australian marine fishes and this is its first report from Australian waters.

  10. Pseudocapillaria (Ichthyocapillaria) ophisterni sp. n. (Nematoda : Capillariidae) from the swamp-eel Ophisternon aenigmaticum (Pisces) in Mexico.

    Science.gov (United States)

    Moravec, F; Salgado-Maldonado, G; Jiménez-García, I

    2000-04-01

    A new nematode species, Pseudocapillaria ophisterni sp. n., is described from the intestine and rarely from the stomach of the swamp-eel, Ophisternon aenigmaticum Rosen et Greenwood, from Catemaco Lake, Veracruz, Mexico. In having both caudal lobes in the male interconnected by a distinct dorsal membrane, it belongs to the subgenus Ichthyocapillaria. It differs from the three species in this subgenus mainly in possessing either a distinctly longer spicule or a smaller length of oesophagus relative to body length. It also differs in host type and geographical distribution. P. ophisterni is the first capillariid species reported from synbranchiform fishes.

  11. The experiments of Ramón M. Termeyer SJ on the electric eel in the River Plate region (c. 1760) and other early accounts of Electrophorus electricus.

    Science.gov (United States)

    de Asúa, Miguel

    2008-01-01

    This paper focuses on Ramón M. Termeyer SJ (1737-1814?), a naturalist who experimented with the electric eel in the River Plate region during the 1760s. After going through an enumeration of the chroniclers that since the sixteenth century noticed the benumbing discharge of Electrophorus electricus, the article summarizes the work that immediately preceded Termeyer's and considers as a term of comparison the experiments on the electric eel performed by Bertrand Bajon (fl. 1751-1778) in the French Guyanne. It ends by discussing the meaning of Termeyer's 1781 and 1810 articles in the light of contemporary ideas of animal electricity.

  12. Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) in eel, trout, and barbel from the River Roya, Northern Italy.

    Science.gov (United States)

    Squadrone, S; Mignone, W; Abete, M C; Favaro, L; Scanzio, T; Foglini, C; Vivaldi, B; Prearo, M

    2015-05-15

    Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) contribute to the dietary intake of total PCBs. They are consumed via ingestion of contaminated fish and fishery products. Thus, it is important to quantify their levels in aquatic organisms in order to evaluate the risks associated with fish consumption by humans. In 2013, an advisory against consumption of fish from the River Roya (IT) was disseminated after NDL PCBs were found to exceed maximum levels set by EU Regulations. We investigated the presence of NDL PCBs in eel, trout and barbel from the River Roya. We found concentrations in the range of 9.2-27.6 ng g(-)(1)ww in barbel, 9.2-97.0 ng g(-1)ww in trout and 9.0-239.5 ng g(-1)ww in eel. The distribution of congeners among different species did not show significant variations and was characterized by a higher proportion of 153, 138 and 180 congeners, according to their high resistance to metabolic degradation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Oxime-mediated in vitro reactivation kinetic analysis of organophosphates-inhibited human and electric eel acetylcholinesterase.

    Science.gov (United States)

    Sahu, Arvind Kumar; Sharma, Rahul; Gupta, Bhanushree; Musilek, Kamil; Kuca, Kamil; Acharya, Jyotiranjan; Ghosh, Kallol K

    2016-06-01

    Organophosphate (OP)-based pesticides and nerve agents are highly toxic compounds which interrupt the catalytic mechanism of acetylcholinesterase (AChE) by phosphorylating the hydroxyl moiety of serine residue. The inhibited enzyme can be reactivated by the nucleophilic action of oxime reactivators. To analyze the effect of different AChE sources on reactivation efficacy of reactivators, several in vivo studies have carried out using variety of AChE sources like pig, rat and monkey. Investigations on species differences provide a better insight for the development of new reactivators. Hence, present study was mainly targeted on comparative analysis of the reactivation of electric eel and human AChE inhibited by different OP. A series of butene-linked bis-pyridinium mono oximes which vary in functional groups present at the second pyridinium ring have been examined against sarin, VX, tabun and ethyl-paraoxon-poisoned AChE. In case of tabun-inhibited AChEs, tested oximes were better than reference oximes. For VX-poisoned human AChE, reactivator K251 (kr2;1.51 mM (-) (1 )min (-) (1)) showed good reactivation efficacy with standard oximes. Studies stipulated that butene-linked oximes consisting of different functional moieties are good reactivators and found to have better efficacy to reactivate nerve agent-inhibited human AChE in comparison to eel AChE.

  14. EELS study of the inverse martensitic transformation of 2H and 18R Cu-Al-Zn alloys

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa-Magana, F., E-mail: francisco.espinosa@cimav.edu.m [Centro de Investigacion en Materiales Avanzados, S.C., Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua, Chih. 31109 (Mexico); Ochoa-Lara, M.T. [Centro de Investigacion en Materiales Avanzados, S.C., Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua, Chih. 31109 (Mexico); Lovey, F. [Centro Atomico Bariloche, 8300 S.C. de Bariloche (Argentina); Flores-Zuniga, H. [Universidad Autonoma de Zacatecaa, Av. Lopez Velarde 801, Zacatecas, Zac. 98060 (Mexico); Rios-Jara, D. [Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, San luis Potosi, S.L.P. 78126 (Mexico)

    2010-01-01

    Changes in 3d states occupancy associated with the inverse martensitic transformation in two samples of Cu-Al-Zn alloys with 2H and 18R martensitic structures were investigated by electron energy loss spectroscopy (EELS). The Cu L{sub 2,3} white-lines intensities, which reflect the unoccupied density of states in 3d bands, were measured in situ, during the phase transformation in both the martensite and austenite phases. We find that the white-lines intensity decreases during the inverse transformation, when going from martensite to austenite. Even though the initial 3d occupation numbers in 2H and 18R martensitic structures are different, after the transformation, the 3d occupation numbers in the now austenitic structure have decreased in both samples, indicating that some electrons left Cu 3d bands during phase transformation. Interestingly enough, the occupation numbers in the final phases, which have the same structure, reach the same value, indicating that changes in EELS spectra are a consequence of structural changes.

  15. Behaviour of wintering Tundra Swans Cygnus columbianus columbianus at the Eel River delta and Humboldt Bay, California, USA

    Science.gov (United States)

    Black, Jeffrey M.; Gress, Carol; Byers, Jacob W.; Jennings, Emily; Ely, Craig

    2010-01-01

    Tundra Swan Cygnus columbianus columbinanus phenology and behaviour at the Eel River delta and southern Humboldt Bay in northern California, USA, is described. Counts made each January from 1963 onwards peaked at 1,502 swans in 1988. Monthly counts recorded during the 2006/07 and 2008/09 winters peaked in February, at 1,033 and 772 swans respectively. Swans roosted on ephemeral ponds at the Humboldt Bay National Wildlife Refuge, on ephemeral ponds within grassland pastures in the vicinity of the Refuge, and perhaps also used the Eel River as a roost. Flights between Refuge roosts and the pastures and ponds occurred in the two hours after sunrise and before dark. In winters 2008/09 and 2009/10, the percentage of cygnets in the flocks was 10.6% and 21.4% respectively, and increased to =31% cygnets each year after most swans had departed from the area in March. Average brood size in 2009/10 was 2.1 cygnets. Daily activities consisted of foraging (44.9% of activities recorded), comfort behaviour (22.1%), locomotion (16.2%) and vigilance (15.5%). Eight neck-collared swans identified in the wintering flock were marked at four locations in different parts of Alaska, up to 1,300 km apart.

  16. Experimental investigation of efficient locomotion of underwater snake robots for lateral undulation and eel-like motion patterns.

    Science.gov (United States)

    Kelasidi, Eleni; Liljebäck, Pål; Pettersen, Kristin Y; Gravdahl, Jan T

    2015-01-01

    Underwater snake robots offer many interesting capabilities for underwater operations. The long and slender structure of such robots provide superior capabilities for access through narrow openings and within confined areas. This is interesting for inspection and monitoring operations, for instance within the subsea oil and gas industry and within marine archeology. In addition, underwater snake robots can provide both inspection and intervention capabilities and are thus interesting candidates for the next generation inspection and intervention AUVs. Furthermore, bioinspired locomotion through oscillatory gaits, like lateral undulation and eel-like motion, is interesting from an energy efficiency point of view. Increasing the motion efficiency in terms of the achieved forward speed by improving the method of propulsion is a key issue for underwater robots. Moreover, energy efficiency is one of the main challenges for long-term autonomy of these systems. In this study, we will consider both these two aspects of efficiency. This paper considers the energy efficiency of swimming snake robots by presenting and experimentally investigating fundamental properties of the velocity and the power consumption of an underwater snake robot for both lateral undulation and eel-like motion patterns. In particular, we investigate the relationship between the parameters of the gait patterns, the forward velocity and the energy consumption for different motion patterns. The simulation and experimental results are seen to support the theoretical findings.

  17. Summer use of the tidal freshwaters of the River Seine by three estuarine fish: Coupling telemetry and GIS spatial analysis

    Science.gov (United States)

    Le Pichon, C.; Coustillas, J.; Zahm, A.; Bunel, M.; Gazeau-Nadin, C.; Rochard, E.

    2017-09-01

    Acoustic telemetry and GIS-based spatial analysis were used to investigate the summer habitat use and movement patterns of three fish species in the tidal freshwaters of the Seine estuary (France). Experimental displacement of tagged individuals of thin-lipped grey mullet (Liza ramada), European eel (Anguilla anguilla), and common bream (Abramis brama) were conducted to test for their spatial fidelity and home range establishment. Most tagged individuals (95%) successfully returned to their previously occupied capture site, showing spatial homing abilities. The studied upstream tidal freshwater segment of the Seine estuary was regularly used by grey mullet as a part of its larger summer home range, while European eel and common bream were resident in this segment. The fidelity of eel to small nocturnal refuges and the regular use of intertidal waterbodies at high tide by grey mullet and bream suggested that they possess a capacity of acquiring spatial memory of habitats in a fluctuating environment. Importantly, the scale of movements travelled by each species was positively related to tidal phase. Grey mullet and bream, both visual feeders, exhibited short-term tidal movements to known habitats, providing food resources and contiguous resting habitat suggesting that they have shown behavioural strategies adaptive to fluctuating environments. Eel, in contrast, was found to have a different strategy strongly related to diel dynamics: it stayed in subtidal habitats rich in refuges that remained available at low tide. The results of this study emphasize the importance of restoring intertidal waterbodies and the relevance of considering the availability of adjacent subtidal habitats providing refuge at low tides.

  18. Air breathing of aquatic burrow-dwelling eel goby, Odontamblyopus lacepedii (Gobiidae: Amblyopinae).

    Science.gov (United States)

    Gonzales, Tomas T; Katoh, Masaya; Ishimatsu, Atsushi

    2006-03-01

    Odontamblyopus lacepedii is an eel goby that inhabits both coastal waters and intertidal zones in East Asia, including Japan. The fish excavates burrows in mudflats but, unlike the sympatric amphibious mudskippers, it does not emerge but stays in the burrows filled with hypoxic water during low tide. Endoscopic observations of the field burrows demonstrated that the fish breathed air in the burrow opening; air breathing commenced 1.3 h following burrow emersion, when water P(O2) was approximately 2.8 kPa, with an air-breathing frequency (f(AB)) of 7.3+/-2.9 breaths h(-1) (mean +/- s.d., N=5). Laboratory experiments revealed that the fish is a facultative air breather. It never breathed air in normoxic water (P(O2)=20.7 kPa) but started bimodal respiration when water P(O2) was reduced to 1.0-3.1 kPa. The fish held air inside the mouth and probably used the gills as gas-exchange surfaces since no rich vascularization occurred in the mouth linings. As is known for other air-breathing fishes, f(AB) increased with decreasing water P(O2). Both buccal gas volume (V(B)) and inspired volume (V(I)) were significantly correlated with body mass (M(b)). At a given M(b), V(I) was nearly always equal to V(B), implying almost complete buccal gas renewal in every breathing cycle. A temporal reduction in expired volume (V(E)) was probably due to a low aerial gas exchange ratio (CO2) elimination/O2 uptake). Air breathing appears to have evolved in O. lacepedii as an adaptation to aquatic hypoxia in the burrows. The acquisition of the novel respiratory capacity enables this species to stay in the burrows during low tide and extends the resident time in the mudflat, thereby increasing its chances of tapping the rich resources of the area.

  19. Characterization and differential expression patterns of conserved microRNAs and mRNAs in three genders of the rice field eel (Monopterus albus).

    Science.gov (United States)

    Gao, Yu; Guo, Wei; Hu, Qing; Zou, Ming; Tang, Rong; Chi, Wei; Li, Dapeng

    2014-01-01

    MicroRNAs (miRNAs) are endogenous small RNAs that can regulate target mRNAs by binding to their sequences in the 3' untranslated region. The expression of miRNAs and their biogenetic pathway are involved in sexual differentiation and in the regulation of the development of germ cells and gonadal somatic cells. The rice field eel (Monopterus albus) undergoes a natural sexual transformation from female to male via an intersex stage during its life cycle. To investigate the molecular mechanisms of this sexual transformation, miRNAs present in the different sexual stages of the rice field eel were identified by high-throughput sequencing technology. A significantly differential expression among the 3 genders (p genders, including mal-miR-430a and mal-miR-430c which were higher in females than in males. However, mal-miR-430b was only detected in males. Several potential miRNA target genes (cyp19a, cyp19b, nr5a1b, foxl2 amh, and vasa) were also investigated. Real-time RT-PCR demonstrated highly specific expression patterns of these genes in the 3 genders of the rice field eel. Many of these genes are targets of mal-miR-430b according to the TargetScan and miRTarBase. These results suggest that the miR-430 family may be involved in the sexual transformation of the rice field eel. © 2014 S. Karger AG, Basel.

  20. Fe valence determination and Li elemental distribution in lithiated FeO₀.₇F₁.₃/C nanocomposite battery materials by electron energy loss spectroscopy (EELS).

    Science.gov (United States)

    Cosandey, F; Su, D; Sina, M; Pereira, N; Amatucci, G G

    2012-01-01

    Electron energy loss spectroscopy (EELS) is a powerful technique for studying Li-ion battery materials because the valence state of the transition metal in the electrode and charge transfer during lithiation and delithiation processes can be analyzed by measuring the relative intensity of the transition metal L₃ and L₂ lines. In addition, the Li distribution in the electrode material can be mapped with nanometer scale resolution. Results obtained for FeO₀.₇F₁.₃/C nanocomposite positive electrodes are presented. The Fe average valence state as a function of lithiation (discharge) has been measured by EELS and results are compared with average Fe valence obtained from electrochemical data. For the FeO₀.₇F₁.₃/C electrode discharged to 1.5 V, phase decomposition is observed and valence mapping with sub-nanometer resolution was obtained by STEM/EELS analysis. For the lowest discharge voltage of 0.8 V, a surface electrolyte inter-phase (SEI) layer is observed and STEM/EELS results are compared with the Li-K edges obtained for various Li standard compounds (LiF, Li₂CO₃ and Li₂O). Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. One-equation sub-grid scale (SGS) modelling for Euler-Euler large eddy simulation (EELES) of dispersed bubbly flow

    NARCIS (Netherlands)

    Niceno, B.; Dhotre, M.T.; Deen, N.G.

    2008-01-01

    In this work, we have presented a one-equation model for sub-grid scale (SGS) kinetic energy and applied it for an Euler-Euler large eddy simulation (EELES) of a bubble column reactor. The one-equation model for SGS kinetic energy shows improved predictions over the state-of-the-art dynamic

  2. State of the art of Italian aquaculture

    Directory of Open Access Journals (Sweden)

    P. Melotti

    2010-04-01

    Full Text Available According to aquaculture production statistics published by FEAP (2007, Italy is the fifth largest fish producer in the European Union having a total quantity for 2006 estimated around 60,000 t. This data is exclusively referred to rainbow trout (Oncorhynchus mykiss, seabream (Sparus aurata, seabass (Dicentrarchus labrax and European eel (Anguilla anguilla but even if we consider the total aquaculture production elaborated by ISMEA (2006 through year 2005 including sturgeons, carps, striped bass, catfish and ornamental fish, Italy ranks fourth with 69,100 t after Norway (655,364 t, Great Britain (141,793 t and Greece (83,600 t. Over the last 15 years, Italian finfish production has known a decrease related to all the species mainly reared (trout, eel, carps, catfish except for the eurhyaline species that have had an important expansion (Table 1. Based on these considerations, in this work we describe the main features of fish aquaculture in Italy focalizing the attention to the single sectors of the farmed species and their trend for the future.

  3. PCB contamination in fish community from the Gironde Estuary (France): blast from the past.

    Science.gov (United States)

    Bodin, N; Tapie, N; Le Ménach, K; Chassot, E; Elie, P; Rochard, E; Budzinski, H

    2014-03-01

    The contamination of the Gironde Estuary, southwest of France, by polychlorinated biphenyls (PCBs) was assessed using six fish of high ecological and economic importance as bioindicator species. The concentrations of 21 PCB congeners and total fat contents were determined in the muscle and liver of eels (Anguilla anguilla), seabass (Dicentrarchus labrax), flounders (Platichthys flesus), meagres (Argyrosomus regius), mullets (Liza ramada), and soles (Solea vulgaris). In addition, information regarding the trophic ecology of the studied fish was obtained through the analysis of carbon and nitrogen stable isotopes (i.e., δ(13)C and δ(15)N) in muscle. Results revealed high PCB concentrations in fish compared to monitored European estuaries. The muscle of eels was by far the most contaminated fish flesh (Σ7PCBs=1000±440 ng g(-1) on a dry weight basis), while the higher PCB concentrations in liver were measured in flounder (Σ7PCBs=2040±1160 ng g(-1) d.w.). A quantile regression approach allowed to investigate the fate of PCBs in the Gironde estuarine fish assemblage, and revealed a general process of trophic magnification. Finally, most of the analysed fish presented PCB concentrations in muscle meat above the current European maximum limits for sea products, while the derived "Toxic Equivalent Quantity" (TEQ) revealed human health concerns only for high-fat fish consumption. Copyright © 2014. Published by Elsevier Ltd.

  4. Cloning of cDNAs and the differential expression of A-type cyclins and Dmc1 during spermatogenesis in the Japanese eel, a teleost fish.

    Science.gov (United States)

    Kajiura-Kobayashi, Hiroko; Kobayashi, Tohru; Nagahama, Yoshitaka

    2005-04-01

    We cloned A-type cyclins (cyclins A1 and A2) and Dmc1 cDNAs from the eel testis. Cyclin A1 mRNA was predominantly expressed in the livers, ovaries, and testes of the eels. In contrast to cyclin A1 mRNA, a very high expression of cyclin A2 mRNA was observed in the brains, livers, kidneys, spleens, ovaries, and testes of the eels. Dmc1 mRNA was predominantly expressed in the testes and ovaries; expression in the brain was also detected. In the eel testis, a few type-A spermatogonia incorporating 5-bromo-2'-deoxyuridine (BrdU) were seen before the initiation of spermatogenesis by hormonal induction. On day 1 after hormonal induction, the number of BrdU-labeled spermatogonia increased remarkably, and after 3 and 6 days, many labeled type-B spermatogonia were also observed. The expression of cyclin A2 increased 1 day after the induction of spermatogenesis and reached a plateau after 6 days, when many type-B spermatogonia with high proliferative activity were found. In contrast, the expression of cyclin A1 mRNA was detected after 9 days, coincident with the first appearance of spermatocytes. Cyclin A1 mRNA was localized in germ cells of all stages, from primary spermatocytes to round spermatids, whereas cyclin A2 mRNA was specifically localized in spermatogonia, secondary spermatocytes, round spermatids, and testicular somatic cells, including Sertoli cells. Dmc1 was localized only in the earlier stages of primary spermatocytes; before this stage, cyclin A1 mRNA was not detectable. Overall, cyclin A2, Dmc1, and cyclin A1 are expressed in spermatogenic cells sequentially before and during meiosis in the eel testis. Copyright 2005 Wiley-Liss, Inc.

  5. Nitrogen redistribution in annealed LaFeOxNy thin films investigated by FTIR spectroscopy and EELS mapping

    Science.gov (United States)

    Haye, Emile; Pierron, Victor; Barrat, Silvère; Capon, Fabien; Munnik, Frans; Bruyère, Stéphanie

    2018-01-01

    LaFeOxNy thin films have been deposited by magnetron sputtering in Ar/O2/N2 gas mixture at 800 °C. Such oxynitride perovskites present a specific infrared vibration mode at 2040 cm-1, due to the presence of nitrogen, which disappears during heating in air. The loss of the vibration mode with temperature has been monitored allowing the determination of an activation energy of thermal degradation of LaFeOxNy. The quantification of nitrogen by Elastic Recoil Detection Analysis (ERDA) before and after heating exhibits the same nitrogen content. Such behavior is due to a nitrogen redistribution observed by Electron Energy Loss Spectroscopy (EELS) mapping, showing migration of nitrogen into grain boundaries, in association with the film oxidation.

  6. Molecular and functional expression of high conductance Ca 2+ activated K+ channels in the eel intestinal epithelium

    DEFF Research Database (Denmark)

    Lionetto, Maria G; Rizzello, Antonia; Giordano, Maria E

    2008-01-01

    Several types of K(+) channels have been identified in epithelial cells. Among them high conductance Ca(2+)-activated K(+) channels (BK channels) are of relevant importance for their involvement in regulatory volume decrease (RVD) response following hypotonic stress. The aim of the present work......) by increasing intracellular Ca(2+) concentration with the Ca(2+) ionophore ionomycin (1 microM). BK(Ca) channels were also activated on both membranes by hypotonic swelling of the epithelium and their inhibition by 100 nM iberiotoxin (specific BK(Ca) inhibitor) abolished the Regulatory Volume Decrease (RVD......) of the intestinal cells after hypotonic swelling. In conclusion, our results demonstrated the molecular and functional expression of high conductance Ca(2+) -activated K(+) channels in eel intestine; the physiological role of these channels is mainly related to the RVD response of the epithelial cells following...

  7. Rise and fall of toxic benthic freshwater cyanobacteria (Anabaena spp.) in the Eel river: Buoyancy and dispersal.

    Science.gov (United States)

    Bouma-Gregson, Keith; Power, Mary E; Bormans, Myriam

    2017-06-01

    Benthic cyanobacteria in rivers produce cyanotoxins and affect aquatic food webs, but knowledge of their ecology lags behind planktonic cyanobacteria. The buoyancy of benthic Anabaena spp. mats was studied to understand implications for Anabaena dispersal in the Eel River, California. Field experiments were used to investigate the effects of oxygen bubble production and dissolution on the buoyancy of Anabaena dominated benthic mats in response to light exposure. Samples of Anabaena dominated mats were harvested from the South Fork Eel River and placed in settling columns to measure floating and sinking velocities, or deployed into in situ ambient and low light treatments to measure the effect of light on flotation. Floating and sinking occurred within minutes and were driven by oxygen bubbles produced during photosynthesis, rather than intracellular changes in carbohydrates or gas vesicles. Light experiment results showed that in a natural ambient light regime, mats remained floating for at least 4days, while in low light mats begin to sink in <24h. Floating Anabaena samples were collected from five sites in the watershed and found to contain the cyanotoxins anatoxin-a and microcystin, with higher concentrations of anatoxin-a (median 560, max 30,693ng/gDW) than microcystin (median 30, max 37ng/gDW). The ability of Anabaena mats to maintain their buoyancy will markedly increase their downstream dispersal distances. Increased buoyancy also allows toxin-containing mats to collect along shorelines, increasing threats to human and animal public health. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. An EELS-based study of the effects of pyrolysis on natural carbonaceous materials used for activated charcoal preparation.

    Science.gov (United States)

    Jeanne-Rose, V; Golabkan, V; Mansot, J L; Largitte, L; Césaire, T; Ouensanga, A

    2003-04-01

    Electron energy-loss spectroscopy (EELS) has been used to characterize the electronic structure of charcoal phases at the nanoscale, thus demonstrating that the technique can be applied to environmental science. Activated charcoal is extensively used to remove pollutants from liquid and gaseous sewage. It is mainly obtained by activation of coke or charcoal produced from ligneous precursors. The present study concerns the use of by-products of local Caribbean agriculture, such as sugar cane bagasse, fruit stones and seeds, for use as activated charcoal precursors. Charcoal phases are prepared by high-temperature pyrolysis of lignocellulosic raw materials under a nitrogen gas flow. With the aim of optimizing the pyrolysis temperature and duration and oxygen content, the concentration of carbon sp2 hybridized chemical bonds and structural ordering have been followed by EELS for different treatment temperatures. To quantify the carbon sp2 content, near edge structure (NES) at the carbon K edge has been measured to determine the strength of pi --> pi* and 1s --> pi* transitions. Three precursors of plant origin, shells of Terminalia catappa and Acrocomia karukerana and seeds of Psidium guajava, with the pyrolysis temperatures between 600 and 900 degrees C, were investigated. The fraction of carbon sp2 bonding is found to increase when the temperature rises from 600 degrees C to the range 700-750 degrees C and becomes stable at higher temperatures. For temperatures in excess of 700 degrees C, structural ordering probably occurs and well-defined 1s --> sigma* NES is present, whose intensity increases with increasing preparation temperature. For the highest temperature of around 900 degrees C, the structure of the final product is less well organized than graphitized carbon but a few per cent of a highly ordered phase is found.

  9. Alexander von Humboldt: galvanism, animal electricity, and self-experimentation part 2: the electric eel, animal electricity, and later years.

    Science.gov (United States)

    Finger, Stanley; Piccolino, Marco; Stahnisch, Frank W

    2013-01-01

    After extensive experimentation during the 1790s, Alexander von Humboldt remained skeptical about "animal electricity" (and metallic electricity), writing instead about an ill-defined galvanic force. With his worldview and wishing to learn more, he studied electric eels in South America just as the new century began, again using his body as a scientific instrument in many of his experiments. As had been the case in the past and for many of the same reasons, some of his findings with the electric eel (and soon after, Italian torpedoes) seemed to argue against biological electricity. But he no longer used galvanic terminology when describing his electric fish experiments. The fact that he now wrote about animal electricity rather than a different "galvanic" force owed much to Alessandro Volta, who had come forth with his "pile" (battery) for multipling the physical and perceptable effects of otherwise weak electricity in 1800, while Humboldt was deep in South America. Humboldt probably read about and saw voltaic batteries in the United States in 1804, but the time he spent with Volta in 1805 was probably more significant in his conversion from a galvanic to an electrical framework for understanding nerve and muscle physiology. Although he did not continue his animal electricity research program after this time, Humboldt retained his worldview of a unified nature and continued to believe in intrinsic animal electricity. He also served as a patron to some of the most important figures in the new field of electrophysiology (e.g., Hermann Helmholtz and Emil du Bois-Reymond), helping to take the research that he had participated in to the next level.

  10. 魚類の細菌感染症の病理組織学的研究

    OpenAIRE

    宮崎, 照雄; Miyazaki, Teruo

    1980-01-01

    The author histopathologically studied Aeromonas hydrophila, Vibrio anguillicida and Edwardsiella tarda infections in Japanese eel (Anguilla japonica) and Streptococcus sp. and Nocardia kampachi infections in cultured yellowtail (Seriola quinqueradiata). Based on the histopathological findings, the author investigated characteristics of the infections and inflammation in fishes in the following pages. Chapter Ⅰ. Aeromonas hydrophila infection in Japanese eel 1) Fifteen naturally infected fish...

  11. EUROPEAN AUSTERITY WITHOUT GROWTH? EUROPEAN GROWTH WITHOUT EUROPEAN DEMOCRACY?

    Directory of Open Access Journals (Sweden)

    Montani Guido

    2011-07-01

    Full Text Available The European project is facing a crisis. Citizens no longer understand what the EU is about. Young people and the new ruling class have forgotten the clear message of the European project launched just after the Second World War "No wars ever again among Europeans." The founding fathers of the European Union are mentioned in history textbooks, but today Europe is felt as an irritating bureaucracy. In Europe, peace and economic stability are considered as a natural state, a gift from above. Why keep a useless EU alive? The state of the European Union is swiftly degenerating. In almost all the member states, the anti-European forces are gaining ground. Populism is not a new ideology and is not necessarily European: let's recall Peronism. In today's Europe populism is the new manifestation of nationalism. In Italy the Lega Nord is in Berlusconi's eurosceptic government. In France, the National Front is endangering UMP's hegemony. In Belgium the rows between the Flemish and the Walloons threatens the state's unity. In the Netherlands, Hungary, the Czech Republic, Austria and Finland, populist forces are either in the government or strongly influencing the government. National-populism is different from the nationalism of the past. De Gaulle's nationalism was an ideology founded on the "grandeur" of France's history and on a certain idea of Europe, which was "l'Europe de patrie", a kind of European unity accepting French leadership in world politics. Today national-populism is a form of micro-nationalism: it opposes the European project but without having a serious alternative. This is why populism is dangerous. Its real goal is not only the breaking down of the European Union but also the disintegration of the old nation states into micro-ethnic states, as what happened in former Yugoslavia.

  12. Expression of aromatase in radial glial cells in the brain of the Japanese eel provides insight into the evolution of the cyp191a gene in Actinopterygians.

    Directory of Open Access Journals (Sweden)

    Shan-Ru Jeng

    Full Text Available The cyp19a1 gene that encodes aromatase, the only enzyme permitting conversion of C19 aromatizable androgens into estrogens, is present as a single copy in the genome of most vertebrate species, except in teleosts in which it has been duplicated. This study aimed at investigating the brain expression of a cyp19a1 gene expressed in both gonad and brain of Japanese eel, a basal teleost. By means of immunohistochemistry and in situ hybridization, we show that cyp19a1 is expressed only in radial glial cells of the brain and in pituitary cells. Treatments with salmon pituitary homogenates (female or human chorionic gonadotrophin (male, known to turn on steroid production in immature eels, strongly stimulated cyp19a1 messenger and protein expression in radial glial cells and pituitary cells. Using double staining studies, we also showed that aromatase-expressing radial glial cells exhibit proliferative activity in both the brain and the pituitary. Altogether, these data indicate that brain and pituitary expression of Japanese eel cyp19a1 exhibits characteristics similar to those reported for the brain specific cyp19a1b gene in teleosts having duplicated cyp19a1 genes. This supports the hypothesis that, despite the fact that eels also underwent the teleost specific genome duplication, they have a single cyp19a1 expressed in both brain and gonad. Such data also suggest that the intriguing features of brain aromatase expression in teleost fishes were not gained after the whole genome duplication and may reflect properties of the cyp19a1 gene of ancestral Actinopterygians.

  13. mRNA-seq reveals skeletal muscle atrophy in response to handling stress in a marine teleost, the red cusk-eel (Genypterus chilensis)

    OpenAIRE

    Aedo, Jorge E.; Maldonado, Jonathan; Aballai, V?ctor; Estrada, Juan M.; Bastias-Molina, Macarena; Meneses, Claudio; Gallardo-Escarate, Cristian; Silva,Herman; Molina, Alfredo; Vald?s, Juan A.

    2015-01-01

    Background Fish reared under intensive conditions are repeatedly exposed to stress, which negatively impacts growth. Although most fish follow a conserved pattern of stress response, with increased concentrations of cortisol, each species presents specificities in the cell response and stress tolerance. Therefore, culturing new species requires a detailed knowledge of these specific responses. The red cusk-eel (Genypterus chilensis) is a new economically important marine species for the Chile...

  14. Combined EXAFS and STEM-EELS study of the electronic state and location of Mn as promoter in Co-based Fischer-Tropsch catalysts

    OpenAIRE

    Morales, F.; Grandjean, D.; de Groot, FMF; Stephan, O.; Weckhuysen, BM

    2005-01-01

    STEM-EELS and EXAFS have been used to investigate the location and electronic state of Mn as promoter in TiO2- supported cobalt Fischer Tropsch catalysts prepared by two different procedures. It was found that the extent of interaction between Mn and the active Co phase as well as the level of Mn dispersion over the TiO2 surface largely determine the enhancement of the selectivity in the Fischer Tropsch synthesis at pressures of 1 bar.

  15. XPS and EELS characterization of Mn{sub 2}SiO{sub 4}, MnSiO{sub 3} and MnAl{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Grosvenor, A.P., E-mail: andrew.grosvenor@usask.ca [Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9 (Canada); Bellhouse, E.M., E-mail: erika.bellhouse@arcelormittal.com [Global R & D—Hamilton, ArcelorMittal Dofasco, 1330 Burlington St. E, Hamilton, ON L8N 3J5 (Canada); Korinek, A., E-mail: korinek@mcmaster.ca [Canadian Centre for Electron Microscopy, Brockhouse Institute for Materials Research, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4M1 (Canada); Bugnet, M., E-mail: bugnetm@mcmaster.ca [Canadian Centre for Electron Microscopy, Brockhouse Institute for Materials Research, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4M1 (Canada); McDermid, J.R., E-mail: mcdermid@mcmaster.ca [Steel Research Centre, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4M1 (Canada)

    2016-08-30

    Graphical abstract: XPS and EELS spectra were acquired from Mn2Al2O4, MnSiO3 and Mn2SiO4 standards and unique features identified that will allow unambiguous identification of these compounds when studying the selective oxidation of advanced steels. - Highlights: • Mn2Al2O4, MnSiO3 and Mn2SiO4 standards were synthesized and characterized using both XPS and EELS. • Unique features in both the XPS high resolution and EELS spectra were identified for all compounds. • The spectra can be used to identify these compounds when studying the selective oxidation of steels. - Abstract: X-ray Photoelectron Spectroscopy (XPS) and Electron Energy Loss Spectroscopy (EELS) are strong candidate techniques for characterizing steel surfaces and substrate-coating interfaces when investigating the selective oxidation and reactive wetting of advanced high strength steels (AHSS) during the continuous galvanizing process. However, unambiguous identification of ternary oxides such as Mn{sub 2}SiO{sub 4}, MnSiO{sub 3}, and MnAl{sub 2}O{sub 4} by XPS or EELS, which can play a significant role in substrate reactive wetting, is difficult due to the lack of fully characterized standards in the literature. To resolve this issue, samples of Mn{sub 2}SiO{sub 4}, MnSiO{sub 3} and MnAl{sub 2}O{sub 4} were synthesized and characterized by XPS and EELS. The unique features of the XPS and EELS spectra for the Mn{sub 2}SiO{sub 4}, MnSiO{sub 3} and MnAl{sub 2}O{sub 4} standards were successfully derived, thereby allowing investigators to fully differentiate and identify these oxides at the surface and subsurface of Mn, Si and Al alloyed AHSS using these techniques.

  16. Educating in European Identity?

    National Research Council Canada - National Science Library

    Enrique Banús

    2007-01-01

    In the last decades, the claim for a "European identity" has been manifested sometimes as a solution for the citizens' distance to the European project, sometimes also as a precondition for a further...

  17. The Influence of Environmental Salinity, Temperature, Ionizing Irradiation and Yellow or Silver Stage on Lipid Metabolism in the Gills of the European Eel

    DEFF Research Database (Denmark)

    Hansen, Heinz Johs. Max; Abraham, S.

    1979-01-01

    The influence of temperature on the incorporation of [32P]phosphate and [14C]acetate into gill lipids in vivo depends also on environmental salinity. - 2. Ionizing irradiation (1000 r) results in a relatively enhanced incorporation of [32P]phosphate into phosphatidyl choline and of [14C]acetate i......The influence of temperature on the incorporation of [32P]phosphate and [14C]acetate into gill lipids in vivo depends also on environmental salinity. - 2. Ionizing irradiation (1000 r) results in a relatively enhanced incorporation of [32P]phosphate into phosphatidyl choline and of [14C......]acetate into triglycerides and wax esters in vivo. - 3. When gill tissue is removed from the animal and incubated in vitro, a pronounced dependence of lipid metabolism on previous environmental salinity is not observed...

  18. Europeanization and transnational states

    DEFF Research Database (Denmark)

    Jacobsson, Bengt; Lægreid, Per; Pedersen, Ove K.

    This work investigates what happens to an organized political unit when it becomes part of a larger entity and, in particular, how increased European integration and the tentative moves towards a transnational state will affect the European Union's nation state. Europeanization and the transforma......This work investigates what happens to an organized political unit when it becomes part of a larger entity and, in particular, how increased European integration and the tentative moves towards a transnational state will affect the European Union's nation state. Europeanization...... in central government agencies. It concludes that the consequences of Europeanization can be described as the growth of a transnational administration where identities as well as loyalties are created in processes that transcend the borders of states....

  19. Characterization of atomic structure of oxide films on carbon steel in simulated concrete pore solutions using EELS

    Energy Technology Data Exchange (ETDEWEB)

    Gunay, H. Burak; Ghods, Pouria [Carleton University, Department of Civil and Environmental Engineering, Ottawa (Canada); Isgor, O. Burkan, E-mail: burkan_isgor@carleton.ca [Carleton University, Department of Civil and Environmental Engineering, Ottawa (Canada); Carpenter, Graham J.C. [CanmetMATERIALS, NRCan, Ottawa (Canada); Wu, Xiaohua [Natural Research Council of Canada, Information and Communications Technologies, Ottawa (Canada)

    2013-06-01

    The atomic structure of oxide films formed on carbon steel that are exposed to highly alkaline simulated concrete pore solutions was investigated using Electron Energy Loss Spectroscopy (EELS). In particular, the effect of chloride exposure on film structure was studied in two types of simulated pore solutions: saturated calcium hydroxide (CH) and a solution prepared to represent typical concrete pore solutions (CP). It was shown that the films that form on carbon steel in simulated concrete pore solutions contained three indistinct layers. The inner oxide film had a structure similar to that of Fe{sup II}O, which is known to be unstable in the presence of chlorides. The outer oxide film mainly resembled Fe{sub 3}O{sub 4} (Fe{sup II}O·Fe{sub 2}{sup III}O{sub 3}) in the CH solution and α-Fe{sub 2}{sup III}O{sub 3}/Fe{sub 3}O{sub 4} in the CP solution. The composition of the transition layer between the inner and outer layers of the oxide film was mainly composed of Fe{sub 3}O{sub 4} (Fe{sup II}O·Fe{sub 2}{sup III}O{sub 3}). In the presence of chloride, the relative amount of the Fe{sup III}/Fe{sup II} increased, confirming that chlorides induce valence state transformation of oxides from Fe{sup II} to Fe{sup III}, and the difference between the atomic structures of oxide film layers diminished.

  20. A long term (1667-1860) perspective on impacts of fishing and environmental variability on fisheries for herring, eel, and whitefish in the Limfjord, Denmark

    DEFF Research Database (Denmark)

    Poulsen, B.; Holm, P.; MacKenzie, Brian

    2007-01-01

    This investigation reconstructs the development of major fisheries for her-ring, eel and whitefish in the Limfjord estuary, Denmark ca. 1667-1860, and then evaluates how their long-term dynamics have been influenced by some key fishery and environmental developments. The commercially most important...... fishery was for herring, Clupea harengus, which spawned in the Limfjord. This fishery underwent large changes in these centuries. High landings occurred in two periods in the early 18th and again in the early 19th centuries, when 4000-8000 metric tonnes were caught annually. In 1830, the fishery collapsed...

  1. THE EUROPEAN BUSINESS CYCLE

    Directory of Open Access Journals (Sweden)

    Ignat Ion

    2009-05-01

    Full Text Available The construction of European Monetary Union has raised several questions about the existence of a common business cycle, a European one. The lack of cyclical synchronization would complicate the monetary and fiscal policies in the Union, being a negative

  2. European Home Energy

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.

    2009-01-01

    An important aim of the european energy performance of buildings directive is to improve the overall energy efficiency of new homes......An important aim of the european energy performance of buildings directive is to improve the overall energy efficiency of new homes...

  3. European Industry, 1700 - 1870

    NARCIS (Netherlands)

    Broadberry, Stephen; Fremdling, Rainer; Solar, Peter M.

    2008-01-01

    This paper offers an overview of the development of European industry between 1700 and 1870, drawing in particular on the recent literature that has emerged following the formation of the European Historical Economics Society in 1991. The approach thus makes use of economic analysis and quantitative

  4. The European Programme Manager

    DEFF Research Database (Denmark)

    Larson, Anne; Bergman, E.; Ehlers, S.

    The publication is a result of a cooperation between organisations in six European countries with the aim to develop a common European education for programme managers. It contains of a description of the different elements of the education together with a number of case-studies from the counties...

  5. European works councils

    DEFF Research Database (Denmark)

    Knudsen, Herman Lyhne

    2003-01-01

    The theme adressed by this paper is the opportunities for European Works Councils (EWCs) of gaining influence on corporate decisions in multinational companies.......The theme adressed by this paper is the opportunities for European Works Councils (EWCs) of gaining influence on corporate decisions in multinational companies....

  6. European works councils

    DEFF Research Database (Denmark)

    Knudsen, Herman Lyhne

    2004-01-01

    The theme addressed by this artcle is the opportunities for European Works Councils of gaining influence on corporate decisions in multinational companies.......The theme addressed by this artcle is the opportunities for European Works Councils of gaining influence on corporate decisions in multinational companies....

  7. Introduction: European climate leadership

    NARCIS (Netherlands)

    Wurzel, R.K.W.; Liefferink, J.D.; Connelly, J.

    2017-01-01

    There is no shortage of would-be leaders in EU climate change politics. The EU institutions (e.g. European Council, Council of the EU, Commission and the European Parliament (EP)), member states and societal actors have all, though to varying degrees and at different time periods, tried to offer

  8. Europeanization : A Poststructuralist Approach

    NARCIS (Netherlands)

    Neuman-Stanivukovic, Senka

    2014-01-01

    This dissertation begins from the hypothesis that the direction and extent of Europeanization depends on domestic perception of the European Union and its norms. Accordingly, it was my empirical ambition to study how competing articulations of the EU and its norms constructed debates in EU member

  9. European media law

    NARCIS (Netherlands)

    Castendyk, O.; Dommering, E.; Scheuer, A.

    2008-01-01

    European Union legislation concerning electronic communications media is firmly established as an essential part of the law in the field in Europe. From relevant provisions of the European Convention of Human Rights and the EC Treaty to numerous directives, the most recent being the Audiovisual

  10. OPTIMALISASI PEMBERIAN PUTIH TELUR AYAM RAS UNTUK MENINGKATKAN KEMEKARAN KERUPUK IKAN BELUT (OPTIMIZATION OF RAS CHICKEN EGG WHITE GIVING TO INCREASE EFFLORESCENCE EEL FISH CRACKERS

    Directory of Open Access Journals (Sweden)

    Candra Candra

    2017-02-01

    Full Text Available Penelitian ini bertujuan untuk mencari konsentrasi putih telur yang optimal untuk meningkatkan kemekaran kerupuk ikan belut dengan perlakuan A tanpa pemberian putoh telur, perlakuan B penambahan putih telur 25 ml, perlakuan C penambahan putih telur 50 ml dan perlakuan D penambahan putih telur 75 ml.  Semua perlakuan dilakukan ulangan tiga kali ulangan dengan Rancangan Acak Lengkap.  Parameter yang diamati adalah kadar protein, kadar air, kadar karbohidrat, uji kerenyahan, uji kemekaran dan uji sensoris.  Berdasarkan hasil penelitian dapat disimpulkan  pemberian putih telur mampu meningkatkan kandungan protein dan kemekaran dan kerenyahan kerupuk ikan belut serta memenuhi Standar Industri Indonesia. This study aims to find the optimal concentration of egg whites to increase efflorescence swamp eel crackers with treatment A without giving egg white, egg white treatment B adding 25 ml, treatment C the addition of 50 ml of egg white and egg white treatment D adding 75 ml. All treatments are performed replications with three replications completely randomized design. Parameters measured were protein content, moisture content, carbohydrate content, crispness test, efflorescence and sensory test. Based on the results of this study concluded giving egg whites to increase the protein content and efflorescence and crispy swamp eel crackers and meet industry standards of Indonesia.

  11. Shelf-life extension of preservative-free hydrated feed using gamma pasteurization and its effect on growth performance of eel

    Science.gov (United States)

    Kim, Dongho; Song, Hyunpa; Lim, Sangyong; Jo, Minho; Song, Duseop; Jo, Cheorun

    2012-08-01

    Hydrated feed (HF) promotes the growth performance and shortens the feeding time of fish by increasing the efficiency of digestion. However, the shelf-life of HF is a concern due to its relatively higher water content. In this study, radiation pasteurization was applied to improve the shelf-life and microbiological quality of HF for fish farming. Preservative-free HF containing 25% moisture was gamma-irradiated and its microbiological and nutritional properties evaluated in addition to a practical feeding trial carried out using eel. The viable counts of bacteria and fungi in HF were 106 and 104 CFU/g, respectively. All coliform bacteria and yeast in HF were eliminated by irradiation at a dose of 5 kGy, and total aerobic bacteria were eliminated at 10 kGy. The shelf-life of the preservative-free and irradiated (10 kGy) HF was estimated as 6 months under ambient conditions. The nutritional composition of HF was stable up to 10 kGy of irradiation. Based on a feeding trial, it was proven that eel fed HF had about 20% higher growth rate than that fed dried feed.

  12. Community ecology of the metazoan parasites of pink cusk-eel, Genypterus brasiliensis (Osteichthyes: Ophidiidae, from the coastal zone of the State of Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Dimitri R Alves

    2002-07-01

    Full Text Available Fifty-five specimens of pink cusk-eel, Genypterus brasiliensis Regan, 1903 (Osteichthyes: Ophidiidae collected from the coastal zone of the State of Rio de Janeiro, Brazil (approx. 21-23°S, 41-45°W, from September 2000 to January 2001, were necropsied to study their parasites. All fish were parasitized by one or more metazoan. Fourteen species of parasites were collected. G. brasiliensis is a new host record for nine parasite species. The larval stages of cestodes and the nematodes were the majority of the parasite specimens collected, with 38.4% and 36.5%, respectively. Cucullanus genypteri was the dominant species with highest prevalence and/or abundance. The parasites of G. brasiliensis showed the typical overdispersed pattern of distribution. Six parasite species showed correlation between the host's total body length and prevalence and abundance. Host sex did not influence prevalence and parasite abundance of any parasite species. The mean diversity in the infracommunities of G. brasiliensis was H= 0.364 ± 0.103, with correlation with the host's total length and without differences in relation to sex of the host. One pair of adult endoparasites (C. genypteri and A. brasiliensis showed positive covariations between their abundances. Negative association or covariation was not found. Differences between the qualitative and quantitative aspects of the parasite community of G. brasiliensis from Rio de Janeiro and Argentina suggest the existence of two population stocks of pink cusk-eel in the South America Atlantic Ocean.

  13. Relative competence of native and exotic fish hosts for two generalist native trematodes

    OpenAIRE

    Paterson, Rachel A.; Lal, Aparna; Dale, Marcia; Colin R Townsend; Poulin, Robert; Tompkins, Daniel M.

    2013-01-01

    Exotic fish species frequently acquire native parasites despite the absence of closely related native hosts. They thus have the potential to affect native counterparts by altering native host–parasite dynamics. In New Zealand, exotic brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss have acquired two native trematodes (Telogaster opisthorchis and Stegodexamene anguillae) from their native definitive host (the longfin eel Anguilla dieffenbachii). We used a combination of field sur...

  14. [Non-indigenous and non-specific parasitic nematodes--the background and the consequences].

    Science.gov (United States)

    Okulewicz, Anna

    2009-01-01

    Introduction of the host is the main reason behind introduction of the parasite, e. g., nematodes. The introduction of the Japanese eel (Anguilla japonica) in Europe in the 1980s resulted in expansion of the swimbladder nematode Anguillicola crassus which soon invaded not only populations of the European eel (A. anguilla), but also other local fish. The raccoon (Procyon lotor) is native to North America. It is the specific host of Strongyloides procyonis and Baylisascaris procyonis. More than 90 species of wild and domestical bird and mammal species, including humans, have been infected with B. procyonis larvae. The larvae enter various organs of paratenic hosts, particularly the central nervous system and eye, causing severe diseases and death. Asthworthius sidemi--a blood-succking, abomasal nematode, a specific parasite of the Asiatic sika deer (Cervus nippon) and sambar deer (C. unicolor)--was first introduced with its hosts into countries adjacent to Poland. A. sidemi is especially dangerous to the European bison (Bison bonasus) which is its new host. The bison populations, in both Białowieza Primaeval Forest and the Bieszczady Mts, sometimes show a 100% prevalence and mass infection intensity. Imported animals, sold in pet shops or available from private breeding firms, often carry non-native parasites. For example, the red-eared tortoise (Trachemys scripta elegans) and Afgan tortoise (Agrionemys horsfieldii) carry nematodes Angusticaecum holopterum, Tachygonetria lobata and T. robusta. Migratory birds in their wintering grounds are often infected with parasites which are usually not constant components of the native fauna, but sometimes nematodes could find a suitable conditions to complete their life cycle. E.g. Cyathosoma microspiculum, species specific to cormorants (Phalacrocorax carbo) and previously recorded only from Asia and the Asian-European boudary, was able complete the life cycle in Poland. The increasingly frequent travels to countries with

  15. A field survey of metal binding to metallothionein and other cytosolic ligands in liver of eels using an on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS).

    Science.gov (United States)

    Van Campenhout, Karen; Goenaga Infante, Heidi; Goemans, Geert; Belpaire, Claude; Adams, Freddy; Blust, Ronny; Bervoets, Lieven

    2008-05-15

    The effect of metal exposure on the accumulation and cytosolic speciation of metals in livers of wild populations of European eel with special emphasis on metallothioneins (MT) was studied. Four sampling sites in Flanders showing different degrees of heavy metal contamination were selected for this purpose. An on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS) was used to study the cytosolic speciation of the metals. The distribution of the metals Cd, Cu, Ni, Pb and Zn among cytosolic fractions displayed strong differences. The cytosolic concentration of Cd, Ni and Pb increased proportionally with the total liver levels. However, the cytosolic concentrations of Cu and Zn only increased above a certain liver tissue threshold level. Cd, Cu and Zn, but not Pb and Ni, were largely associated with the MT pool in correspondence with the environmental exposure and liver tissue concentrations. Most of the Pb and Ni and a considerable fraction of Cu and Zn, but not Cd, were associated to High Molecular Weight (HMW) fractions. The relative importance of the Cu and Zn in the HMW fraction decreased with increasing contamination levels while the MT pool became progressively more important. The close relationship between the cytosolic metal load and the total MT levels or the metals bound on the MT pool indicates that the metals, rather than other stress factors, are the major factor determining MT induction.

  16. A hybrid method using the widely-used WIEN2k and VASP codes to calculate the complete set of XAS/EELS edges in a hundred-atoms system.

    Science.gov (United States)

    Donval, Gaël; Moreau, Philippe; Danet, Julien; Larbi, Séverine Jouanneau-Si; Bayle-Guillemaud, Pascale; Boucher, Florent

    2017-01-04

    Most of the recent developments in EELS modelling has been focused on getting a better agreement with measurements. Less work however has been dedicated to bringing EELS calculations to larger structures that can more realistically describe actual systems. The purpose of this paper is to present a hybrid approach well adapted to calculating the whole set of localised EELS core-loss edges (at the XAS level of theory) on larger systems using only standard tools, namely the WIEN2k and VASP codes. We illustrate the usefulness of this method by applying it to a set of amorphous silicon structures in order to explain the flattening of the silicon L 2,3 EELS edge peak at the onset. We show that the peak flattening is actually caused by the collective contribution of each of the atoms to the average spectrum, as opposed to a flattening occurring on each individual spectrum. This method allowed us to reduce the execution time by a factor of 3 compared to a usual-carefully optimised-WIEN2k calculation. It provided even greater speed-ups on more complex systems (interfaces, ∼300 atoms) that will be presented in a future paper. This method is suited to calculate all the localized edges of all the atoms of a structure in a single calculation for light atoms as long as the core-hole effects can be neglected.

  17. Update of European bioethics

    DEFF Research Database (Denmark)

    Rendtorff, Jacob Dahl

    2015-01-01

    , the principles of autonomy, dignity, integrity and vulnerability are proposed as the most important ethical principles for respect for the human person in biomedical and biotechnological development. This approach to bioethics and biolaw is presented here in a short updated version that integrates the earlier......This paper presents an update of the research on European bioethics undertaken by the author together with Professor Peter Kemp since the 1990s, on Basic ethical principles in European bioethics and biolaw. In this European approach to basic ethical principles in bioethics and biolaw...... research in a presentation of the present understanding of the basic ethical principles in bioethics and biolaw....

  18. Democratic Citizenship: European referents

    Directory of Open Access Journals (Sweden)

    María PUIG GUTIÉRREZ

    2011-09-01

    Full Text Available Let’s sense beforehand in this article a tour concerning the educational European policies that favors the development of a democratic citizenship. The aim that we chase is to understand the way in which nowadays it is being interpreted and stimulated the Citizenship education from European Union. for it we offer a conceptual delimiting of «Citizenship education» and later, we show an analysis of the principal documents and materials elaborated principally by the Council of Europe that mark the way followed by European Union as for education for Democratic Citizenship (EDC.

  19. CERN welcomes European science

    CERN Multimedia

    2002-01-01

    On 3 and 4 October CERN will host a special workshop for Marie Curie fellows. This programme is a key plank in the EU's strategy for creating a European research area.     With thousands of scientists from all over the continent working together, CERN is already an exemplary European science showcase. On 3 and 4 October, the Laboratory will contribute further to unifying all European science by hosting a special workshop for EU-funded Marie Curie fellows. This scheme gives young researchers from around the continent the mobility to go to wherever Europe's best facilities in their chosen field happen to be. The event that will take place at CERN, entitled 'Special workshop of Marie Curie Fellows on research and training in physics and technology', organised together with the European Commission, is a continuation of a series of workshops with the aim, among others, of promoting young researchers, supporting their training and mobility, and facilitating the interdisciplinary dissemination of knowledge. Dur...

  20. European Economic Integration

    Science.gov (United States)

    Huston, James A.

    1971-01-01

    Recounts the history and problems of European Economic Integration from the first post World War II organization, the OEEC, to the EEC (Common Market) and the EFTA. Suggestions for further reading are included. (JB)

  1. European Molecular Biology Laboratory

    CERN Multimedia

    1973-01-01

    On 10 May an Agreement was signed at CERN setting up a new European Laboratory. It will be concerned with research in molecularbiology and will be located at Heidelberg in the Federal Republic of Germany.

  2. The European University Landscape

    DEFF Research Database (Denmark)

    Daraio, Cinzia; Bonaccorsi, Andrea; Geuna, Aldo

    2011-01-01

    This paper provides a new and systematic characterization of 488 universities, from 11 European countries: Finland, France, Germany, Hungary, Italy, Netherlands, Norway, Portugal, Spain, Switzerland and UK. Using micro indicators built on the integrated Aquameth database, we characterize the Euro...

  3. European mobility cultures

    DEFF Research Database (Denmark)

    Haustein, Sonja; Nielsen, Thomas A. Sick

    2016-01-01

    More targeted European policies promoting green travel patterns require better knowledge on differing mobility cultures across European regions. As a basis for this, we clustered the EU population into eight mobility styles based on Eurobarometer data. The mobility styles - including, for example......-economic resources. In a second step, the 28 EU member countries were clustered into six country clusters based on their representation of mobility styles. The country clusters indicate the existence of considerably different mobility cultures across the EU. Sub-regions can be identified that have highly different...... positions on the path towards sustainable mobility and therefore different requirements towards European platforms and support measures, e.g. for 'Sustainable Urban Mobility Plans'. The country clusters can provide a starting point for future communication and targeting of European efforts in sustainable...

  4. European Cyber Security Policy

    OpenAIRE

    Bendiek, Annegret

    2012-01-01

    The gradually developing European cyber security policy tries to establish minimum standards in all EU member states with regard to prevention, resilience and international cooperation. It aims to foster national security without compromising democratic principles or unduly limiting individual liberties. However, it is hard to find a balance between these goals, and the EU’s measures thus inevitably raise questions about the democratic implications of European cyber security policy. Are the i...

  5. Timetabling on European Corridors

    OpenAIRE

    Lischke, Andreas; Führer, B. (Bernhard); Garavagno, G.

    2005-01-01

    The Path Allocation Re-engineering of Timetable Networks for European Railways (PARTNER) project aims to demonstrate a new way of train path allocation and assembly along international corridors towards a faster and more coordinated railway infrastructure capacity management. PARTNER will assist two neighbour infrastructure managers to develop a common understanding of the effects of international train paths. The results of a survey of European infrastructure managers and railway underta...

  6. European Physical Society awards

    CERN Multimedia

    2004-01-01

    The winners of the 2004 Accelerator Prizes, awarded by the European Physical Society's Interdivisional Group on Accelerators (EPS-IGA), have been announced. Vladmir Shiltsev (Fermilab) and Igor Meshkov (JINR, Joint Institute of Nuclear Research, Dubna) will be presented with their awards during the 9th European Particle Accelerator Conference, EPAC'04, on 8 July 2004 in Lucerne. Both physicists will also give a talk about their work. More details on: http://epac.web.cern.ch/

  7. European Banking Union

    OpenAIRE

    Breuss, Fritz

    2013-01-01

    The ongoing Euro crisis and the worse economic development in Europe than in the USA are grounded, not the least in the delayed implementation of reforms of the banking sector. Whereas the leaks in economic governance of EMU have been fixed the banking sector is still not stabilised, even five years after Lehman Brothers. From the grand solution of a "European Banking Union" (EBU) only the first pillar, the European Bank Supervision with the single supervisory mechanism (SSM) will come into e...

  8. European DHC Research Issues

    Energy Technology Data Exchange (ETDEWEB)

    Wiltshire, Robin; Williams, Jonathan (Building Research Establishment, BRE, Bucknalls Lane, Watford (United Kingdom)); Werner, Sven (Halmstad University, School of Business and Engineering, Halmstad (Sweden))

    2008-09-15

    Euroheat and Power is now working towards a European Technology Platform for District Heating and Cooling. In response to this important European DHC research initiative, a preliminary detailed list of research issues within 18 dimensions was elaborated and communicated to more than 100 people in February 2008. After additions and comments received, an updated list of research issues was again distributed in July 2008. This paper contains the current list of suggested research issues

  9. Habermas on European Constitution and European Identity

    Directory of Open Access Journals (Sweden)

    Éva Biró-Kaszás

    2010-12-01

    Full Text Available For the last two decades or so philosophers have been reflecting on a set of practical and political concerns in connection with the new political structural arrangements beyond the nation-state. In this article two essays by Jürgen Habermas shall be examined. An attempt shall be made to tackle Habermas’ philosophical concepts of personal and collective identity as well as the role that a constitution may play in building the post-national constellation. It has been shown that Habermas has normative answers. Firstly, according to him, the fragile balance between the legal order and the particular cultures and traditions of a community has to be protected by the constitutional state. For that reason the political culture has to be “decoupled” from the majority culture. Secondly, the democratically structured attempt to achieve shared meaning has to find the delicate balance between the context-transcending universal normative claims and the claims of particular individual and collective life. Thirdly, it is possible to expand legally mediated civil solidarity trans-nationally, across Europe – we may recognize this development as the emergence of European identity –, since the process of democratic will-formation of citizens may get loose from the structures provided by the state if both shared democratic political cultures as well as a European-wide public sphere exist. The European Constitution may have a catalytic function in materialization of these conditions. It has been shown that in his deliberations Habermas tried to find a reflective equilibrium between the normative and the empirical.

  10. Phylogeography of the Chinese Beard Eel, Cirrhimuraena chinensis Kaup, Inferred from Mitochondrial DNA: A Range Expansion after the Last Glacial Maximum

    Directory of Open Access Journals (Sweden)

    Hai Li

    2014-08-01

    Full Text Available The Chinese beard eel (Cirrhimuraena chinensis Kaup is an intertidal fish and a model organism for the study of impacts caused by topological fluctuations during the Pleistocene and current intricate hydrological conditions on fauna living in the coastal areas of China. In this study, we examined the phylogeographical pattern, population genetic profile and demographical history of C. chinensis using mitochondrial DNA (cytochrome b (cyt b and control region (CR from 266 individuals sampled in seven localities across the coastal area of southeastern China. The combined data indicated high levels of haplotype diversity and low levels of nucleotide diversity. Analyses of molecular variance (AMOVA and FST statistics suggested the absence of a significant population structure across the Chinese coast. Neutrality tests, mismatch distributions and Bayesian skyline plots uniformly indicated a recent population expansion. The phylogeographic structure of C. chinensis may be attributed to past population expansion and long-distance pelagic larval dispersal facilitated by present-day ocean currents.

  11. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments obtained during the R/V Discovery EEL_2011_D365 Cruise Along Extended Ellett Line from 2011-05-20 to 2011-05-31 (NCEI Accession 0157258)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157258 includes chemical, discrete sample, physical and profile data obtained during the R/V Discovery EEL_2011_D365 Cruise Along Extended Ellett...

  12. Diversified cardiovascular actions of six homologous natriuretic peptides (ANP, BNP, VNP, CNP1, CNP3, and CNP4) in conscious eels.

    Science.gov (United States)

    Nobata, Shigenori; Ventura, Albert; Kaiya, Hiroyuki; Takei, Yoshio

    2010-06-01

    The natriuretic peptide (NP) family consists of seven paralogs [atrial NP (ANP), brain NP (BNP), ventricular NP (VNP), and C-type NP 1-4 (CNP1-4)] in teleosts, but relative biological activity of the seven NPs has not been comprehensively examined using homologous peptides. In this study, we newly identified CNP3 and CNP4 in eels to use homologous peptides, but the CNP2 gene may have been silenced in this species. The CNP4 gene was expressed exclusively in the brain as CNP1, but the CNP3 gene, from which cardiac ANP, BNP, and VNP were generated by tandem duplication, was most abundantly expressed in the pituitary, suggesting its local action. All NPs induced hypotension dose dependently after intra-arterial injection with a potency order of ANP > VNP > BNP > CNP4 > CNP1 = CNP3. The degree of hypotension was similar at the ventral and dorsal aorta, indicating similar actions on the branchial and systemic circulation. The hypotension induced by cardiac NPs was longer lasting than CNPs, probably because of the difference in preferential receptors. Among cardiac NPs, the hypotensive effect of VNP lasted much longer than those of ANP and BNP, even though VNP disappeared from the blood more quickly than ANP. To analyze the unique effect of VNP, we examined possible involvement of the autonomic nervous system using ANP, VNP, and CNP3. Beta-adrenergic blockade diminished hypotensive effects of all three NPs, but alpha-adrenergic and cholinergic blockade enhanced only the effect of VNP, suggesting a specific mechanism for the VNP action. The NP-induced tachycardia was diminished by all blockers examined. Furthermore, the cardiovascular action of VNP was not impaired by a blocker of NP receptor, HS-142-1. Taken together, the homologous NPs exhibit diverse cardiovascular actions in eels partially through the autonomic nervous system, and the unique VNP action may be mediated by a novel receptor that has not been identified in teleosts.

  13. mRNA-seq reveals skeletal muscle atrophy in response to handling stress in a marine teleost, the red cusk-eel (Genypterus chilensis).

    Science.gov (United States)

    Aedo, Jorge E; Maldonado, Jonathan; Aballai, Víctor; Estrada, Juan M; Bastias-Molina, Macarena; Meneses, Claudio; Gallardo-Escarate, Cristian; Silva, Herman; Molina, Alfredo; Valdés, Juan A

    2015-12-01

    Fish reared under intensive conditions are repeatedly exposed to stress, which negatively impacts growth. Although most fish follow a conserved pattern of stress response, with increased concentrations of cortisol, each species presents specificities in the cell response and stress tolerance. Therefore, culturing new species requires a detailed knowledge of these specific responses. The red cusk-eel (Genypterus chilensis) is a new economically important marine species for the Chilean aquaculture industry. However, there is no information on the stress- and cortisol-induced mechanisms that decrease skeletal muscle growth in this teleost. Using Illumina RNA-seq technology, skeletal muscle sequence reads for G. chilensis were generated under control and handling stress conditions. Reads were mapped onto a reference transcriptome, resulting in the in silico identification of 785 up-regulated and 167 down-regulated transcripts. Gene ontology enrichment analysis revealed a significant up-regulation of catabolic genes associated with skeletal muscle atrophy. These results were validated by RT-qPCR analysis for ten candidates genes involved in ubiquitin-mediated proteolysis, autophagy and skeletal muscle growth. Additionally, using a primary culture of fish skeletal muscle cells, the effect of cortisol was evaluated in relation to red cusk-eel skeletal muscle atrophy. The present data demonstrated that handling stress promotes skeletal muscle atrophy in the marine teleost G. chilensis through the expression of components of the ubiquitin-proteasome and autophagy-lysosome systems. Furthermore, cortisol was a powerful inductor of skeletal muscle atrophy in fish myotubes. This study is an important step towards understanding the atrophy system in non-model teleost species and provides novel insights on the cellular and molecular mechanisms that control skeletal muscle growth in early vertebrates.

  14. Measurement of the dynamic charge response of materials using low-energy, momentum-resolved electron energy-loss spectroscopy (M-EELS

    Directory of Open Access Journals (Sweden)

    Sean Vig, Anshul Kogar, Matteo Mitrano, Ali A. Husain, Vivek Mishra, Melinda S. Rak, Luc Venema, Peter D. Johnson, Genda D. Gu, Eduardo Fradkin, Michael R. Norman, Peter Abbamonte

    2017-10-01

    Full Text Available One of the most fundamental properties of an interacting electron system is its frequency- and wave-vector-dependent density response function, $\\chi({\\bf q},\\omega$. The imaginary part, $\\chi''({\\bf q},\\omega$, defines the fundamental bosonic charge excitations of the system, exhibiting peaks wherever collective modes are present. $\\chi$ quantifies the electronic compressibility of a material, its response to external fields, its ability to screen charge, and its tendency to form charge density waves. Unfortunately, there has never been a fully momentum-resolved means to measure $\\chi({\\bf q},\\omega$ at the meV energy scale relevant to modern electronic materials. Here, we demonstrate a way to measure $\\chi$ with quantitative momentum resolution by applying alignment techniques from x-ray and neutron scattering to surface high-resolution electron energy-loss spectroscopy (HR-EELS. This approach, which we refer to here as ``M-EELS" allows direct measurement of $\\chi''({\\bf q},\\omega$ with meV resolution while controlling the momentum with an accuracy better than a percent of a typical Brillouin zone. We apply this technique to finite-{\\bf q} excitations in the optimally-doped high temperature superconductor, Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ (Bi2212, which exhibits several phonons potentially relevant to dispersion anomalies observed in ARPES and STM experiments. Our study defines a path to studying the long-sought collective charge modes in quantum materials at the meV scale and with full momentum control.

  15. Transnational European Television Drama

    DEFF Research Database (Denmark)

    Bondebjerg, Ib; Redvall, Eva Novrup; Helles, Rasmus

    This book deals with the role of television drama in Europe as enabler of transnational, cultural encounters for audiences and the creative community. It demonstrates that the diversity of national cultures is a challenge for European TV drama but also a potential richness and source of creative...... variation. Based on data on the production, distribution and reception of recent TV drama from several European countries, the book presents a new picture of the transnational European television culture. The authors analyse main tendencies in television policy and challenges for national broadcasters...... coming from new global streaming services. Comparing cases of historical, contemporary and crime drama from several countries, this study shows the importance of creative co-production and transnational mediated cultural encounters between national cultures of Europe....

  16. The Europeanization of Eurosceptics?

    DEFF Research Database (Denmark)

    Dutceac Segesten, Anamaria; Bossetta Jr, Michael Joseph

    with the case of Sweden. Sweden is a good example because it has a high density of internet use, a politically active population as reflected in voter turnout and many politicians and political parties with a web presence. The main research questions of the paper are: Which actors are involved in the Swedish...... of a Europeanized network of anti-European voices for European integration and democracy. We plan to operationalize our research question through the use of webcrawling (i.e. Issue Crawler) and social media analytic softwares (Twitonomy and Bluenod). Using these softwares we will be able to discern whether...... or not non-Swedish Twitter users are participating in and/or affecting the Swedish Eurosceptic dialogue on social media....

  17. European Analytical Column

    DEFF Research Database (Denmark)

    Karlberg, B.; Grasserbauer, M.; Andersen, Jens Enevold Thaulov

    2009-01-01

    The European Analytical Column has once more invited a guest columnist to give his views on various matters related to analytical chemistry in Europe. This year, we have invited Professor Manfred Grasserbauer of the Vienna University of Technology to present some of the current challenges...... for European analytical chemistry. During the period 2002–07, Professor Grasserbauer was Director of the Institute for Environment and Sustainability, Joint Research Centre of the European Commission (EC), Ispra, Italy. There is no doubt that many challenges exist at the present time for all of us representing...... a major branch of chemistry, namely analytical chemistry. The global financial crisis is affecting all branches of chemistry, but analytical chemistry, in particular, since our discipline by tradition has many close links to industry. We have already noticed decreased industrial commitment with respect...

  18. European Universe Awareness

    Science.gov (United States)

    Russo, P.; Miley, G.; Westra van Holthe, F.; Schrier, W.; Reed, S.

    2011-10-01

    The European Universe Awareness (EU-UNAWE) programme uses the beauty and grandeur of the cosmos to encourage young children, particularly those from underprivileged backgrounds, to develop an interest in science and technology and to foster a sense of global citizenship. EU-UNAWE is already active in 40 countries and comprises a global network of almost 500 astronomers, teachers and other educators. The programme was recently awarded a grant of 1.9 million euros by the European Union so that it can be further developed in five European countries and South Africa. The grant will be used to organise teacher training workshops and to develop educational materials, such as an astronomy news service for children and games. During this presentation we will outline some of the biggest achievements of EU-UNAWE to date and discuss future plans for the programme.

  19. The European Identity

    Directory of Open Access Journals (Sweden)

    Alberto Martinelli

    2017-09-01

    Full Text Available European identity is not only a scientifically interesting question, but also a politically important issue: in fact, sixty years after the signing of the Treaty of Rome, the European Union finds itself for the first time facing risks that threaten its own existence. The European Union is a limited and incomplete project because Europe’s economic integration has not been accompanied by a genuine supranational political union and greater cultural integration. The deficit of democratic representation and cultural integration is due to the fact that the community process is based only on economic rationality and not on a feeling of common belonging. In the current situation in which the Union faces difficult challenges which threaten to undermine the future, it necessary to affirm the policy of interests with a policy of identity. In this essay, we will first concentrate on the concept of identity – that is on the nucleus of values and common institutions –; then we will discuss how the European identity has changed over time (also in relation to national identities and what are the mechanisms that may favour its taking root in the current situation. The European project of political unification needs to be re-emphasized, finding the way to a European collective identity, not contrasted with but alongside the different national identities, referring to loyalty and shared commitment to a whole collection of cultural values: fundamental human rights, civil liberties, democratic political institutions, rule of law, freedom of movement of people, goods and capital, social justice and non-violent resolution of conflicts.

  20. European Gas Dependency

    OpenAIRE

    Antonsen, Iben; Bieber, Martin; Gandrup, Tobias; Lehmann, Tina; Weinberger, Ashley

    2008-01-01

    The focal point of the project is, as it is implied in the title, European gas dependency, to be more specific; the dependency of Russian gas. We chose Russia, because the EU's import of gas is mainly supplied by Russia. We present background information and knowledge to describe why the case is of relevance and that a situation of dependency exists. We solely look at the dependency from the European Union's point of view, taking point of departure in the Green Paper. The Green Paper is a pap...

  1. European Values and Globalization

    Directory of Open Access Journals (Sweden)

    Heinz Theisen

    2011-03-01

    Full Text Available Good Governance, Social Market Economy, Culture and Education are the decisive elements for Human Development. We need a third way between the extremes of the Utopian Global Free Market and a new nationalism. A Social Market Economy and the European Model of a Union could be such third way. For a new Social Market Economy we need a renaissance of the European dialectics between culture and society, idealism and materialism, religion and enlightenment, solidarity and profitability. The balancing of those poles is deeply rooted in our best traditions. 

  2. Causality in Europeanization Research

    DEFF Research Database (Denmark)

    Lynggaard, Kennet

    2012-01-01

    to develop discursive institutional analytical frameworks and something that comes close to the formulation of hypothesis on the effects of European Union (EU) policies and institutions on domestic change. Even if these efforts so far do not necessarily amount to substantive theories or claims of causality...

  3. Measuring European selves

    DEFF Research Database (Denmark)

    Antalikova, Radka

    Taking the perspective of cross-cultural psychology, the current thesis sets out to investigate self in a European context. For this purpose, the thesis first thoroughly reviews the most prominent conceptualizations of self in cross-cultural psychology, specifically focusing on disentangling...... to the field of cross-cultural psychology, specifically highlighting the utility of autobiographical memories as measures of self....

  4. European Psychology Map

    Directory of Open Access Journals (Sweden)

    DANA SCHÖN

    2009-06-01

    Full Text Available The Institute for Psychology Information (ZPID compiled an extensive list of European psycho-logical organizations, comprised of university departments, research institutions, professional associa-tions and publishing houses. The list is available on the ZPID website, together with a web mapping applet that indicates the exact geographical location of the organizations.

  5. European Pine Shoot Moth

    Science.gov (United States)

    William E. Miller; Arthur R. Hastings; John F. Wootten

    1961-01-01

    In the United States, the European pine shoot moth has caused much damage in young, plantations of red pine. It has been responsible for reduced planting of red pine in many areas. Although attacked trees rarely if ever die, their growth is inhibited and many are, deformed. Scotch pine and Austrian pine (Pinus nigra Arnold) are usually not so badly damaged. Swiss...

  6. Inequalities in European cities

    NARCIS (Netherlands)

    Musterd, S.; Ostendorf, W.; Smith, S.J.; Elsinga, M.; Eng, O.S.; Fox O’Mahony, L.; Wachter, S.

    2012-01-01

    The consequences of inequalities in European cities are a big fear for many governments at the state and urban levels. Journalists, as well as many scholars who are dealing with urban issues, express their fears about the development of social, ethnic, and spatial divisions. Population categories

  7. European 'Stabilisation through Association'

    DEFF Research Database (Denmark)

    Rodt, Annemarie Peen

    ’s success in repeatedly reconciling a divided continent and complemented its efforts to build peace beyond its borders. But does the EU (continue to) deserve such praise? This contribution examines European peacebuilding from the early inte-gration of post-World War Two economies, through the uniting...

  8. European Integration and Globalization

    Directory of Open Access Journals (Sweden)

    Diana Bobica

    2010-06-01

    Full Text Available According to many, the term globalization is able to explain any phenomenon whatsoever, be it positive or negative, that takes place within the global social system. It seems like a sort of magical formula, which is to be found in the speeches of all sorts of people, be they economists, politicians, businessmen or sociologists. However this magical formula of globalization has its limitations, since it encompasses a certain amount of quibbling, beyond which not many can pass. In the context of globalization there appears the question on its role in the process of European integration. Is European integration a part of this global process or, quite on the contrary, does it present certain distinctive features, as it moulds itself differently from the globalization phenomenon? A clear-cut answer seems difficult because of the various aspects involved. Not only the general phenomenon of globalization, but also the economic integration on European level is based on the liberalization of markets and on the opening of national economies towards the exterior,having as direct consequence the intensification of trade exchanges. If from a global point of view one may talk of a market fundamentalism in that the market principles know no boundary, European integration on the other hand implies not only market economy, but also a guided and monitored action of Member Statesaccording to the needs of the whole entity, also taking into consideration - as far as possible – all aspects and consequences on social level.

  9. Becoming Pan-European?

    DEFF Research Database (Denmark)

    Schulz-Forberg, Hagen; Brüggemann, Michael

    2009-01-01

    be platforms of a transnational European discourse. Four ideal-types of transnational media can be distinguished: (1) national media with a transnational mission, (2) international media, (3) pan-regional media and (4) global media. Within this framework the article analyses transnational media in Europe...

  10. European Metals Conference

    CERN Document Server

    Vereecken, Jean

    1991-01-01

    This volume contains the papers that will be presented at 'EMC '91 '-the European Metals Conference-to be held in Brussels, Belgium, from 15 to 20 September 1991, and organized by Benelux Metallurgie, GDMB (Gesellschaft Deutscher Metallhutten­ und Bergleute) and IMM (the Institution of Mining and Metallurgy). 'EMC '91' is the first of an intended major series organized at the European level with the aim of bringing together all those who are involved with the extraction and processing of non-ferrous metals-European metallurgists and their international colleagues-to provide them with the opportunity to exchange views on the state and evolution of their industry. The programme covers all the different aspects of the metallurgy of non-ferrous metals from mining to fabricated products. Particular attention is being paid to the European non -ferrous industry with respect to changes in demand, the technology used, pressures on the environment and the competitive position of manufacturers. The contributions of the...

  11. AND THE EUROPEAN UNION

    African Journals Online (AJOL)

    Regulations governing the production and use of genetically modified organisms have been developed in the United Kingdom since 1976. Regulations covering the release of transgenic organisms into the environment were initially voluntary. Since 1990, the European Economic Commission (EEC) Directive. 90/219 and ...

  12. European Music Year 1985.

    Science.gov (United States)

    Alexanderson, Thomas; And Others

    1984-01-01

    Articles concerning music are included in this newsletter dedicated to cultural venture to be jointly carried out by the Council of Europe and the European communities. Many events will mark Music Year 1985, including concerts, dance performances, operas, publications, recordings, festivals, exhibitions, competitions, and conferences on musical…

  13. Time trends in fish populations in metropolitan France: insights from national monitoring data.

    Science.gov (United States)

    Poulet, N; Beaulaton, L; Dembski, S

    2011-12-01

    Using the electrofishing database of the French National Agency for Water and Aquatic Environment (Onema), the time trends of 48 freshwater fish taxa at 590 sites monitored for at least 8 years from 1990 to 2009 were investigated. The results demonstrated that species richness increased steadily from the beginning of the monitoring period. This is congruent with the finding that the number of species displaying a significant increase in spatial distribution or abundance was greater than those showing a significant decrease. Some species, however, had declined both in occurrence and abundance, e.g. tench Tinca tinca, common bream Abramis brama, brown trout Salmo trutta and European eel Anguilla anguilla. The species showing the most spectacular colonization were non-native, e.g. topmouth gudgeon Pseudorasbora parva, wels catfish Silurus glanis and asp Aspius aspius. The time trends in population density were related to the maximal body size, habitat requirement, occurrence and abundance and the status (i.e. native or exotic) but not to the spawning temperature. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

  14. Development and validation of a range of endogenous controls to support the implementation of practical Taqman real-time PCR-based surveillance for fish diseases within aquaculture.

    Science.gov (United States)

    Bland, F; McIntosh, R; Bain, N; Snow, M

    2012-06-01

    The use of Taqman real-time PCR-based technology has recently become more frequent in the detection of pathogens in the aquaculture industry. This interest has necessitated the development of robust and reliable pathogen-detection assays. The development of a range of endogenous control assays to be run alongside these diagnostic assays works to further increase confidence in the latter. This study describes the design of a range of endogenous control assays based on the elongation factor 1-α (EF1-α) gene specific to a range of fish species including Atlantic salmon, Salmo salar; rainbow trout, Oncorhynchus mykiss; brown trout, Salmo trutta; cod, Gadus morhua; haddock, Melanogrammus aeglefinus; saithe, Pollachius virens; whiting, Merlangius merlangus; Norway pout, Trisopterus esmarkii; carp (family Cyprinidae), roach, Rutilus rutilus; European eel, Anguilla anguilla; and herring, Clupea harengus, as well as a number of fish cell lines. Evidence is provided of the validation of these assays for specific species, a range of tissue types and cell lines as well as an example of the potential uses of these assays. © 2012 Crown copyright.

  15. First detection of Mnemiopsis leidyi (Ctenophora, Bolinopsidae in Sardinia (S’Ena Arrubia Lagoon, Western Mediterranean: a threat for local fishery and species recruitment

    Directory of Open Access Journals (Sweden)

    R. DICIOTTI

    2016-07-01

    Full Text Available The invasive comb jelly Mnemiopsis leidyi is a lobate ctenophore native of coastal and estuarine waters of the temperate western Atlantic Ocean. In the last decades this species has expanded its range of distribution, colonizing marine and transitional environments in Europe. In October 2015, during a survey fishing the European eel Anguilla anguilla in Sardinia (western Mediterranean, a massive bloom of this specie was observed in the eutrophic S’Ena Arrubia Lagoon for the first time. In November 2015, sampling was conducted at three stations in the lagoon and in a fyke net, in order to estimate the abundance of M. leidyi and to determine its impact on the fishing activity. The results showed an abundance of 2.83 ctenophores m-3. Specimens were all adults, measuring 18 - 62 mm total length. The abundant number of ctenophores (6837 individuals per fyke net damaged fishing operations, reducing catches and affecting the performance of fishing gears. Since there is no effective mechanical, chemical or biological method to counter M. leidyi, the short term economic damage may be approached by new management measures of fisheries. In addition, other actions against the recurring of M. leidyi invasion, can include management strategies, in particular those finalized to reduce the high trophic state of the lagoon.

  16. The Europeanness of European cinema: Identity, meaning, globalization

    OpenAIRE

    Willems, Gertjan

    2015-01-01

    According to its editors, the aim of The Europeanness of European cinema is ‘to revisit the issue of the significance of European cinema as a category in the wake of the recent acceleration in transnational filmmaking and globalization as a whole’ (p. 7). Taking the transnational prominence of European cinema as a starting point, the anthology’s introduction presents some brief reflections about what ‘Europeanness’ – the central, overarching concept for the various chapters – has meant histor...

  17. European core curriculum in neurorehabilitation

    NARCIS (Netherlands)

    Sandrini, G.; Binder, H.; Homberg, V.; Saltuari, L.; Tarkka, I.; Smania, N.; Corradini, C.; Giustini, A.; Katterer, C.; Picari, L.; Diserens, K.; Koenig, E.; Geurts, A.C.; Anghelescu, A.; Opara, J.; Tonin, P.; Kwakkel, G.; Golyk, V.; Onose, G.; Perennou, D.; Picelli, A.

    2017-01-01

    To date, medical education lacks Europe-wide standards on neurorehabilitation. To address this, the European Federation of NeuroRehabilitation Societies (EFNR) here proposes a postgraduate neurorehabilitation training scheme. In particular, the European medical core curriculum in neurorehabilitation

  18. European and Integration Studies

    Directory of Open Access Journals (Sweden)

    N. Yu. Kaveshnikov

    2014-01-01

    Full Text Available Soviet scientific school of pan-European integration studies began to emerge in the 1960s at the Institute of World Economy and International Relations (Russian Academy of Science. Among the leading scientists who have developed methodological approaches of Soviet integration studies were M.M. Maximova, Y.A. Borko, Y. Shishkov, L.I. Capercaillie. Later, a new center for integration studies became the Institute of Europe, created in 1987. It was led by such renowned scientists as Academicians V.V. Zhurkin and N.P. Shmelev. In the 1980s the subject of the integration process in Europe attracted attention of experts from MGIMO. An important role in the development of school of integration research in the USSR was played by a MGIMO professor, head of the chair of history of international relations and foreign policy of the USSR V.B. Knyazhinskiy. His work contributed to the deliverance of the national scientific community from skepticism about the prospects for European integration. Ideas of V.B. Knyazhinsky are developed today in MGIMO by his followers A.V. Mal'gin and T.V. Ur'eva. In the mid-1990s, having retired from diplomatic service, professor Yu. Matveevskiy started to work at MGIMO. With a considerable practical experience in the field, he produced a series of monographs on the history of European integration. In his works, he analyses the development of integration processes in Western Europe from their inception to the present day, showing the gradual maturation of the necessary spiritual and material prerequisites for the start of integration and traces the various stages of the "integration". In the late 1990s, the growing demand from the domestic business and government for professionals who are capable of interacting with the European Union, has produced the necessary supply in the form of educational programs based on accumulated scientific knowledge. Setting up a discipline "European Integration" was a major step in the development

  19. From a physicist's toy to an indispensable analytical tool in many fields of science: A personal view of the leading contribution of Ondrej Krivanek to the spectacular successes of EELS spectroscopy in the electron microscope.

    Science.gov (United States)

    Colliex, Christian

    2017-09-01

    This contribution aims at reporting, from the subjective point of view of a witness based in Orsay, the fundamental role of Ondrej Krivanek in the spectacular emergence of EELS (Electron Energy-Loss Spectroscopy) as a key tool in analytical electron microscopy. In this regard, he has successively designed and built while he was at Gatan, serial EELS spectrometers, parallel EELS spectrometers and post-column energy filters which have been fitted to many different (S)TEM columns installed around the world. More recently the implementation of monochromators on the NION dedicated STEM together with the realization and performance of aberration correctors (which lie out of the scope of the present review), have placed the most advanced instrumental tool in the hands of continuously increasing populations of users in many domains of materials science and in life sciences. Furthermore, the impact of Ondrej Krivanek has spread widely beyond his technical achievements into that of a highly respected organizer of workshops, bringing together at regular intervals, all the experts from around the world and building up a real community of scientists. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. The Shoah within European identity

    NARCIS (Netherlands)

    van der Poel, Stefan

    2016-01-01

    In the Epilogue of Postwar, titled: From the House ofthe Dead: An essay on Modern European memory, Tony Judt concludes that: ‘those who would become full Europeans in the dawn of the twenty-first century must first assume a new and far more oppressive heritage. Today the pertinent European reference

  1. Future European biogas

    DEFF Research Database (Denmark)

    Meyer, A. K.P.; Ehimen, E. A.; Holm-Nielsen, J. B.

    2017-01-01

    Biogas is expected to play an important role in reaching the future energy policy targets of the European Union (EU). The sustainability of biogas substrates has however been recently critically discussed due to the increasing shares of agricultural land used for energy crop production.The aim...... were animal manure, straw by-products from cereal production, and excess grass from rotational and permanent grasslands and meadows. The biogas energy potential from the investigated biomass was projected to range from 1.2·103 to 2.3·103 PJ y-1 in year 2030 in the EU28, depending on the biomass...... availability. Alone the biogas energy potential projected in the scenario representing low substrate availability corresponds to a doubling of the European biogas production in 2015. The results shows that sustainable alternatives to the use of maize are present in all the member states of the EU28...

  2. European Patterns of Participation

    DEFF Research Database (Denmark)

    Harrebye, Silas Fehmerling; Ejrnæs, Anders

    2015-01-01

    Social Survey (ESS) Round 4 (2008), the article finds that satisfaction/dissatisfaction with the government is an important predictor alongside the institutional macro-level variable. The article combines a critical tradition, which suggests that political participation is motivated by a feeling...... of dissatisfaction with the government and feelings of being member of a discriminated group affect the level of extra-parliamentary participation, and second, how different welfare regimes condition the extend to which these groups chose to act. In a comparative multilevel design, using data from the European...... of dissatisfaction with an institutional perspective in which certain institutional conditions are seen as enablers for citizens to actively participate in political life. Our results show that the overall level of extra-parliamentary activity in the Scandinavian countries is higher than in the other European...

  3. Chestnut, European (Castanea sativa).

    Science.gov (United States)

    Corredoira, Elena; Valladares, Silvia; Vieitez, Ana M; Ballester, Antonio

    2015-01-01

    Development of a system for direct transfer of antifungal candidate genes into European chestnut (Castanea sativa) would provide an alternative approach to conventional breeding for production of chestnut trees that are tolerant to ink disease caused by Phytophthora spp. Overexpression of genes encoding PR proteins (such as thaumatin-like proteins), which display antifungal activity, may represent an important advance in control of the disease. We have used a chestnut thaumatin-like protein gene (CsTL1) isolated from European chestnut cotyledons and have achieved overexpression of the gene in chestnut somatic embryogenic lines used as target material. We have also acclimatized the transgenic plants and grown them on in the greenhouse. Here, we describe the various steps of the process, from the induction of somatic embryogenesis to the production of transgenic plants.

  4. Do Europeans Like Nudges?

    DEFF Research Database (Denmark)

    Reisch, Lucia A.; Sunstein, Cass R.

    2016-01-01

    In recent years, many governments have shown a keen interest in “nudges” — approaches to law and policy that maintain freedom of choice, but that steer people in certain directions. Yet to date, there has been little evidence on whether citizens of various societies support nudges and nudging. We...... report the results of nationally representative surveys in six European nations: Denmark, France, Germany, Hungary, Italy, and the United Kingdom. We find strong majority support for nudges of the sort that have been adopted, or under serious consideration, in democratic nations. Despite the general...... European consensus, we find markedly lower levels of support for nudges in two nations: Hungary and Denmark. We are not, in general, able to connect support for nudges with distinct party affiliations....

  5. Pirating European Studies

    Directory of Open Access Journals (Sweden)

    Natalia Timus

    2016-08-01

    Full Text Available Open Science has gained a lot of attention not only within the academic community but also among policy-makers. Some international publishers have been active in moving towards open access publications and research data, but, overall, modest results have been achieved so far. In this context, the digital piracy engines emerge as vital actors in disseminating and determining the impact of research. This study examines the Sci-Hub downloads data in order to uncover patterns of piracy in European Studies research. We identify journals and the subjects of articles that have been pirated the most. We also study the geographical distribution of download requests. The analysis reveals that the readers are mostly interested in subjects reflecting the current major European challenges, specifically populism and the economic crisis. Both developing countries as well as the ‘old’ EU members are active in illegal downloads.

  6. Stature of early Europeans.

    Science.gov (United States)

    Hermanussen, Michael

    2003-01-01

    The ancestors of modern Europeans arrived in Europe at least 40,000 years before present. Pre-glacial maximum Upper Palaeolithic males (before 16,000 BC) were tall and slim (mean height 179 cm, estimated average body weight 67 kg), while the females were comparably small and robust (mean height 158 cm, estimated average body weight 54 kg). Late Upper Palaeolithic males (8000-6600 BC) were of medium stature and robusticity (mean height 166 cm, estimated average body weight 62 kg). Stature further decreased to below 165 cm with estimated average body weight of 64 kg in Neolithic males of the Linear Band Pottery Culture, and to 150 cm with estimated average body weight of 49 kg in Neolithic females. The body stature of European males remained within the range of 165 to 170 cm up to the end of the 19th century.

  7. European Corporate Law

    DEFF Research Database (Denmark)

    Werlauff, Erik; Dorresteijn, Adriaan; Teichmann, Christoph

    This fully updated new edition provides the best-known practical overview of the law regarding companies, business activities, and capital markets in Europe, at both the European Union (EU) and Member State levels. It incorporates analysis of recent developments including the impact of global......; - a company’s freedom to incorporate in a jurisdiction not its own; - competition among the legal forms of different Member States; and - safeguarding of employee involvement in cross-border transactions. With respect to national law, the laws of Belgium, France, Germany, the Netherlands, Poland, Spain...... initiatives in such aspects of the corporate environment as regulation of financial institutions and non-financial reporting obligations with a view to sustainability and other social responsibility concerns. The authors, all leading experts in European corporate law, describe current and emerging trends...

  8. Telemedicine and European law.

    Science.gov (United States)

    Callens, Stefaan

    2003-01-01

    A Directive of the European Union was first published in 2000, which dealt with telemedicine as part of its provisions. This E-Commerce Directive, as it became known, was subjected to further study which revealed some problems relative to the practice of telemedicine. Among the subjects discussed in this paper are those of privacy, data protection, free movement of services, the impact of electronic communication and ethical issues.

  9. European Automotive Congress

    CERN Document Server

    Clenci, Adrian

    2016-01-01

    The volume includes selected and reviewed papers from the European Automotive Congress held in Bucharest, Romania, in November 2015. Authors are experts from research, industry and universities coming from 14 countries worldwide. The papers are covering the latest developments in fuel economy and environment, automotive safety and comfort, automotive reliability and maintenance, new materials and technologies, traffic and road transport systems, advanced engineering methods and tools, as well as advanced powertrains and hybrid and electric drives.

  10. Geography of European Migration

    Directory of Open Access Journals (Sweden)

    Zhitin Dmitry V.

    2016-08-01

    Full Text Available In recent decades, the role of international migration has increased dramatically in most European countries. The growth in migration has made some authors proclaim the beginning of a second Migration Period that could transform the social and cultural identity of Europe. The article presents an analysis of international migration geography in Europe in the last twenty-five years. The authors identify the main trends in migration, provide migration profiles of European countries, and propose a classification based on the recent changes in the migrant stock. Changes in the migrant stock (total emigration and immigration reflect the level of involvement in international and global processes. They can serve as an indicator of a country’s attractiveness for both foreigners and the country’s citizens. The study shows that European countries are increasingly split into ‘immigrant’ and ‘emigrant’ states. The authors describe spatial patterns of migration. The volume and localisation of migration flows in Europe are affected not only by cultural and historical circumstance, such as a colonial past or a common language. The scale of immigrant influx often does not depend on a donor country’s demographic potential or the level of its socio-economic development. The links between the place of origin and destination are often more complex than it might initially seem. The authors stress the importance of a differentiated immigration policy taking into account ethnic and cultural features of host societies.

  11. European Law in the Making:

    DEFF Research Database (Denmark)

    Rasmussen, Morten

    the legal service of the High Authority from early on promoted a ‘constitutional’ interpretation of European law, but where the member state, as well as most legal experts, still considered European law a subset of international law. How did the Court of Justice of the ECSC manoeuvre between...... on European law in the making.......Traditionally, the Court of Justice of the European Coal and Steel Community (ECSC) has mainly been considered the somewhat dull predecessor to the more famous Court of Justice of the European Communities, which in 1963-64 ‘constitutionalised’ the Treaties of Rome with the seminal judgments of Van...

  12. A Hot Knife Through Ice-Cream: Earthflow Response to Channel Incision (Or Channel Response to Earthflows?), Eel River Canyon, California

    Science.gov (United States)

    Mackey, B. H.; Roering, J. J.; McKean, J. A.

    2007-12-01

    Abundant glacier-like earthflow features are recognized as a primary erosional process in the highly erodable Franciscan Melange of the Eel River Basin, CA. Despite their prominence in this "melting ice-cream" topography, many questions regarding their effects on the long term sediment flux from this rapidly eroding basin remain unresolved. For example, does an earthflow's basal shear zone propagate vertically downwards with vertical river incision? What controls the upslope and lateral extent of individual earthflows? How does the erosive power of a river influence the rate of earthflow movement, or conversely do earthflow toe deposits regulate the rate of river incision? Here we present preliminary findings derived from study of 200km2 of lidar data (1m resolution) covering hillslopes adjacent to 30km of the Eel River. Lidar allows detailed analysis of the interaction between earthflows and the drainage network, and we document how inferred changes in local base level are propagated throughout adjacent hillslopes via earthflow movement. The most active earthflows (determined by field surveying and analysis of aerial photos rectified using lidar- generated digital topography) coincide with locally steep sections of channel, while downstream of the most active flows we frequently observe less-active or dormant earthflows. This observation supports the idea that the locations of the most active earthflows coincide with headward propagating knickpoints in the channel. The rate of earthflow movement appears to slow when an earthflow exhausts the upslope area of easily mobilized sediment. Earthflow toes can protrude directly into the channel, causing the channel to narrow and steepen, and even undercut the opposite bank. Large resistant boulders (>2m diameter) transported by the earthflow accumulate in the streambed and appear to both act as a check on further channel incision and earthflow movement. In contrast, areas adjacent to active earthflows exhibit smooth

  13. Eastern Dimension of the European Neighbourhood Policy: Europeanization Mutual Trap

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    V. A. Latkina

    2014-01-01

    Full Text Available The article analyses the Europeanization policy of the European Union towards the Eastern Partnership participant countries. Suffering from the lack of clear strategy and ultimate goal in the European Neighbourhood Policy the European Union enhances external democratization and its governance in post soviet states without immediate Union's membership perspective. Underestimation of common neighbourhood geopolitical duality in the context of growing rivalry between European (EU and Eurasian (Custom Union/Eurasian Economic Union integration gravitation centers presents the Eastern partners of the EU with a fierce dilemma of externally forced immediate geopolitical and civilizational choice while not all of them are well prepared to such a choice. The mutual Europeanization trap here to be studied both for the EU and its Eastern partners (involving Russia is a deficiency of regulating cooperation mechanism in the situation of European and Eurasian free trades zones overlapping. Vilnius Summit 2013 results test the "European aspirations" of the New Independent States and upset the ongoing process of the European Neighbourhood Policy in the context of growing economic interdependence in Wider Europe. Besides, the Ukrainian crisis escalation during 2014 as a new seat of tension provokes unbalance of the whole European security system and creates new dividing lines in Europe from Vancouver to Vladivostok.

  14. The European populist challenge

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    Yannis Stavrakakis

    2013-01-01

    Full Text Available In today’s Europe, the word ‘populism’ usually refers to right-wing populism or the populist extreme right. Is, however, the concept of ‘populism’ the proper theoreticopolitical instrument through which such identifications should be perceived, categorized and debated? What are the implications (direct and indirect of such a naming? And what are the risks for critical analysis and for democratic politics in the European context? The hypothesis explored in this essay is that sticking to a restrictive association between ‘populism’ and the extreme right poses certain dangers that have to be seriously taken into account, especially in times of crisis. For a start, it is often premised on a rather simplistic euro-centrism that reduces the broad conceptual spectrum covered by the category ‘populism’ in its global use to a very particular European experience and then essentializes the resulting association, over-extending its scope. In addition, the category ‘populism’ is aften used to describe political forces, identities and discourses in which the role of ‘the people’ is only secondary or peripheral, to the extent that it has to coincide with strongly hierarchical and elitist visions of society. What complicates things even further is that, within the context of the European (economic and political crisis, whoever questions/ resists the austerity agenda – especially on the left – is increasingly discredited and denounced as an irresponsible populist. Indeed, it is not by coincidence that doubts are increasingly voiced both in the theoretical and in the political literature regarding the rationale behind such a strong association between populism and the extreme right. A series of points will thus be raised that may help us develop a plausible theoretico-political strategy in the new emerging conditions from a discursive perspective.*

  15. European Network Against Racism

    DEFF Research Database (Denmark)

    Nielsen, Helene Pristed

    of discussions about intersectionality, the article investigates ENAR´s attention and ability to integrate questions of e.g. gender, sexuality or age in their policy input, given the potentially rigid compartmentalisation of discrimination strands within the European Commission´s system of civil society...... consultations. The article therefore overall aims to assess ENAR´s position as potentially hemmed in between 1) the Commission vs. member organisations’ expectations for its focus and modus operandi and 2) attention to intersectional discrimination vs. potential compartmentalisation within the Commission...

  16. Cooperative strategies European perspectives

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    Killing, J Peter

    1997-01-01

    Cooperative Strategies: European Perspectives is one of three geographically targeted volumes in which the contributors present the most current research on topics such as advances in theories of cooperative strategies, the formation of cooperative alliances, the dynamics of partner relationships, and the role of information and knowledge in cooperative alliances. Blending conceptual insights with empirical analyses, the contributors highlight commonalities and differences across national, cultural, and trade zones. The chapters in this volume are anchored in a wide set of theoretical approaches, conceptual frameworks, and models, illustrating how rich the area of cooperative strategies is for scholarly inquiry.

  17. European Regional Modernism

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    Vincent Brian Canizaro

    2014-03-01

    Full Text Available In recent years, beginning with the publication in 2003 of Liane Lefaivre and Alexander Tzonis’ 'Critical Regionalism', followed by my 'Architectural Regionalism: Collected Writings on Place, Identity, Modernity and Tradition 'in 2007, there has been a quiet resurgence in the discourse of architectural regionalism.' 'Leuven University Press’s 'Regionalism and Modernity: Architecture in Western Europe 1914–1940 'continues in this direction, with eleven chapters devoted to variations of the regionalist tendency in European architecture focused primarily on Belgium and France, but also Great Britain, Italy, and Germany.

  18. European Union of Memories?

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    Wæhrens, Anne

    After a very brief introduction to history and memory in Europe after 1989, as seen by Aleida Assmann, I will give a short introduction to the EP and to their adoption of resolutions and declarations. Then I will define some concepts central to my study before I proceed to the analysis. Finally I...... these changes have come about. Moreover, I show that there seems to be a political memory split between Left and Right and I suggest that the time might not be ripe for a shared European memory....

  19. European Union Budget Politics

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    Citi, Manuele

    2015-01-01

    The marginal involvement of the European Union (EU) in redistributive policies and its limited fiscal resources have led to a notable lack of attention by EU scholars towards the EU budget and its dynamics. Yet the nature of the budgetary data and their high usability for statistical analysis make...... them an excellent tool for studying and measuring policy change in the EU. In this article, I analyse an original dataset containing yearly data for the main categories of expenditure and how they have changed over the last three decades (1979–2013). Using time-series analysis, I find that the ability...

  20. How campaigns enhance European issues voting during European Parliament elections

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    Beach, Derek; Møller Hansen, Kasper; Larsen, Martin Vinæs

    2017-01-01

    allegiances less important and attitudes about the European project more important by informing voters of and getting them interested in European politics. In effect, we argue that the political campaign leading up to the election makes European Parliament elections less second-order. While previous studies...... have demonstrated that EU attitudes can matter for voting behavior in European Parliament elections, existing research has drawn on post-election surveys that do not enable us to capture campaign effects. Our contribution is to assess the impact of a campaign by utilizing a rolling cross sectional......Based on findings from the literature on campaign effects on the one hand, and the literature on European Parliament elections on the other, we propose a model of European Parliamentary elections in which the campaign shift the calculus of electoral support, making differences in national political...