WorldWideScience

Sample records for swamp eels synbranchidae

  1. 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.

  2. 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.

  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. A new genus of proteocephalid tapeworm (Cestoda) from the marbled swamp eel Synbranchus marmoratus Bloch (Synbranchiformes: Synbranchidae) in the River Paraná basin, Argentina.

    Science.gov (United States)

    Arredondo, Nathalia J; Alves, Philippe Vieira; Gil de Pertierra, Alicia A

    2017-05-05

    Synbranchiella gen. n. is proposed to accommodate Synbranchiella mabelae sp. n. (Proteocephalidae: Monticelliinae) from the intestine of the marbled swamp eel Synbranchus marmoratus Bloch, in the River Colastiné, a tributary of the middle River Paraná in Argentina. The new genus is placed in the Monticelliinae because of the cortical position of the genital organs. It differs from all known monticelliine genera by the following combination of characters: (i) scolex robust, with a conical apex, without metascolex; (ii) biloculate suckers with a conspicuous septum separating unequally-sized loculi and a robust non-adherent area, lacking free posterior margin; (iii) vitelline follicles in two narrow lateral bands, extended throughout the nearly entire proglottid length; (iv) vagina always anterior to the cirrus-sac, with an inconspicuous vaginal sphincter; (v) a genital pore pre-equatorial. Scanning electron microscopy revealed three types of microtriches on the tegument surface: acicular and capiliform filitriches and gladiate spinitriches. A phylogenetic analysis of the large subunit nuclear ribosomal RNA gene (lsrDNA, D1-D3 domains) confirms that S. mabelae represents an independent lineage within a large clade comprised mainly from Neotropical taxa parasitising catfishes. This is the second proteocephalidean cestode described from a Neotropical synbranchiform fish host.

  5. 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.

  6. 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.

  7. 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.

  8. 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...

  9. 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.

  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. Properties and expression of Na+/K+-ATPase α-subunit isoforms in the brain of the swamp eel, Monopterus albus, which has unusually high brain ammonia tolerance.

    Directory of Open Access Journals (Sweden)

    Xiu L Chen

    Full Text Available The swamp eel, Monopterus albus, can survive in high concentrations of ammonia (>75 mmol l(-1 and accumulate ammonia to high concentrations in its brain (4.5 µmol g(-1. Na(+/K(+-ATPase (Nka is an essential transporter in brain cells, and since NH4(+ can substitute for K(+ to activate Nka, we hypothesized that the brain of M. albus expressed multiple forms of Nka α-subunits, some of which might have high K(+ specificity. Thus, this study aimed to clone and sequence the nka α-subunits from the brain of M. albus, and to determine the effects of ammonia exposure on their mRNA expression and overall protein abundance. The effectiveness of NH4(+ to activate brain Nka from M. albus and Mus musculus was also examined by comparing their Na(+/K(+-ATPase and Na(+/NH4(+-ATPase activities over a range of K(+/NH4(+ concentrations. The full length cDNA coding sequences of three nkaα (nkaα1, nkaα3a and nkaα3b were identified in the brain of M. albus, but nkaα2 expression was undetectable. Exposure to 50 mmol l(-1 NH4Cl for 1 day or 6 days resulted in significant decreases in the mRNA expression of nkaα1, nkaα3a and nkaα3b. The overall Nka protein abundance also decreased significantly after 6 days of ammonia exposure. For M. albus, brain Na(+/NH4(+-ATPase activities were significantly lower than the Na(+/K(+-ATPase activities assayed at various NH4(+/K(+ concentrations. Furthermore, the effectiveness of NH4(+ to activate Nka from the brain of M. albus was significantly lower than that from the brain of M. musculus, which is ammonia-sensitive. Hence, the (1 lack of nkaα2 expression, (2 high K(+ specificity of K(+ binding sites of Nkaα1, Nkaα3a and Nkaα3b, and (3 down-regulation of mRNA expression of all three nkaα isoforms and the overall Nka protein abundance in response to ammonia exposure might be some of the contributing factors to the high brain ammonia tolerance in M. albus.

  12. High brain ammonia tolerance and down-regulation of Na+:K+:2Cl(- Cotransporter 1b mRNA and protein expression in the brain of the Swamp Eel, Monopterus albus, exposed to environmental ammonia or terrestrial conditions.

    Directory of Open Access Journals (Sweden)

    Yuen K Ip

    Full Text Available Na(+:K(+:2Cl(- cotransporter 1 (NKCC1 has been implicated in mediating ischemia-, trauma- or ammonia-induced astrocyte swelling/brain edema in mammals. This study aimed to determine the effects of ammonia or terrestrial exposure on ammonia concentrations in the plasma and brain, and the mRNA expression and protein abundance of nkcc/Nkcc in the brain, of the swamp eel Monopterusalbus. Ammonia exposure led to a greater increase in the ammonia concentration in the brain of M. albus than terrestrial exposure. The brain ammonia concentration of M. albus reached 4.5 µmol g(-1 and 2.7 µmol g(-1 after 6 days of exposure to 50 mmol l(-1 NH4Cl and terrestrial conditions, respectively. The full cDNA coding sequence of nkcc1b from M. albus brain comprised 3276 bp and coded for 1092 amino acids with an estimated molecular mass of 119.6 kDa. A molecular characterization indicated that it could be activated through phosphorylation and/or glycosylation by osmotic and/or oxidative stresses. Ammonia exposure for 1 day or 6 days led to significant decreases in the nkcc1b mRNA expression and Nkcc1b protein abundance in the brain of M. albus. In comparison, a significant decrease in nkcc1b mRNA expression was observed in the brain of M. albus only after 6 days of terrestrial exposure, but both 1 day and 6 days of terrestrial exposure resulted in significant decreases in the protein abundance of Nkcc1b. These results are novel because it has been established in mammals that ammonia up-regulates NKCC1 expression in astrocytes and NKCC1 plays an important role in ammonia-induced astrocyte swelling and brain edema. By contrast, our results indicate for the first time that M. albus is able to down-regulate the mRNA and protein expression of nkcc1b/Nkcc1b in the brain when confronted with ammonia toxicity, which could be one of the contributing factors to its extraordinarily high brain ammonia tolerance.

  13. Predator-prey interactions between Synbranchus marmoratus (Teleostei: Synbranchidae) and Hypsiboas pulchellus tadpoles (Amphibia: Hylidae): importance of lateral line in nocturnal predation and effects of fenitrothion exposure.

    Science.gov (United States)

    Junges, Celina M; Lajmanovich, Rafael C; Peltzer, Paola M; Attademo, Andres M; Bassó, Agustín

    2010-11-01

    Environmental contaminants can disrupt interactions between aquatic species by altering community structure. We explored predator-prey interactions between marbled swamp juvenile eels (Synbranchus marmoratus; predator) and anuran tadpoles (Hypsiboas pulchellus; prey) in relation to two aspects: the importance of lateral line in the predator and whether the absence of light modifies predation rates; and the effect of a sub-lethal concentration of fenitrothion on both predator and prey. Eels were tested under two sensory conditions (lateral line intact and lateral line blocked by cobalt chloride) in dark conditions. Predation rates were evaluated using different treatments that combined predator and prey exposed or not to insecticide. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were also measured in muscle samples of eels and tadpoles to explore whether fenitrothion affects predator and prey differentially. Marbled swamp eels were more efficient in feeding on tadpoles during the night than during the day, showing that lateral line makes an important contribution to prey detection and capture. Regarding pesticide effects, short-term (6 h) exposure to an ecologically relevant fenitrothion dose of 2.5 mg L(-1) altered the predator-prey relationship by changing prey behaviour, reducing prey detection and therefore increasing tadpole survival. At this concentration, the outcome of the predator-prey relationship appears biased in favor of the exposed tadpoles, which were released from predation risk, despite their altered behaviour and the higher inhibition percentages of tail BChE (70%) and AChE (51%) than in control individuals. Our study involving these model species and agrochemicals demonstrates that fenitrothion affected the outcome of a predator-prey relationship. Further studies are needed, in these species and other native amphibians, to investigate the nature of the mechanisms responsible for the adverse effects of pesticides on

  14. The Great Dismal Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This introduction to the natural history of the Great Dismal Swamp is presented at a time when 50,000 acres of the Swamp are being converted from private holdings to...

  15. 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.

  16. Southern deepwater swamps

    Science.gov (United States)

    William H. Conner; Marilyn A. Buford

    1998-01-01

    The authors define, classify, and analyze the economic significance of southern deepwater swamps. They discuss the physical environment, vegetational communities, animal communities, management issues, and research needs for this complex resource.

  17. Dismal Swamp Wildlife

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Conceived and constructed by nature the Great Swamp is the most gigantic filtration plant ever built; and more. To protect the health of the wildlife, for which-...

  18. Dismal Swamp Staff Gages

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Well design - Dismal Swamp Shallow observation wells - these are the early wells put in during 1975, 1976. They are black ABS plastic, 2-inch diameter, open at the...

  19. 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

  20. Swamp Works- Multiple Projects

    Science.gov (United States)

    Carelli, Jonathan M.; Schuler, Jason M.; Chandler, Meredith L.

    2013-01-01

    My Surface Systems internship over the summer 2013 session covered a broad range of projects that utilized multiple fields of engineering and technology. This internship included a project to create a command center for a 120 ton regolith bin, for the design and assembly of a blast shield to add further protection for the Surface Systems engineers, for the design and assembly of a portable four monitor hyper wall strip that could extend as large as needed, research and programming a nano drill that could be utilized on a next generation robot or rover, and social media tasks including the making of videos, posting to social networking websites and creation of a new outreach program to help spread the word about the Swamp Works laboratory.

  1. 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...

  2. 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.

  3. 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.

  4. Remote Sensing of Wetland Types: Peat Swamps

    NARCIS (Netherlands)

    Hoekman, D.H.

    2017-01-01

    Deposits of peat underneath peat swamp forests are among the world’s largest reservoirs of carbon. Although tropical peatlands occupy only about 0.3 % of the global land surface, they could contain as much as 20 % of the global soil carbon stock, representing 63–148 Gt of carbon.

    Peat swamp

  5. 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.

  6. 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.

  7. The Aquatic Coleoptera of the Dismal Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A brief review of the aquatic habitats and an annotated list of the aquatic Cleoptera of the Dismal Swamp is presented. Six families with a total of 53 species are...

  8. The Great Dismal Swamp A Brief Interpretation

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — All through man's experience with the Dismal swamp, People old as well as young, women as well as men have been drawn to it, repelled by it and completely fascinated...

  9. Phytomass Budgets for the Dismal Swamp Ecosystem

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Great Dismal Swamp is a heterogeneous ecosystem as a result of various human disturbances. We studied the phytomass distribution in four community types in the...

  10. 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...

  11. Kennedy Space Center: Swamp Works

    Science.gov (United States)

    DeFilippo, Anthony Robert

    2013-01-01

    When I began my internship with the Granular Mechanics and Regolith Operations laboratory (GMRO), also known as Swamp Works, I was given the unique opportunity to shadow many teams working on various projects, and decide what projects I wanted to take part in. Before I go into details of my experiences at Swamp Works, I would like to take a moment to explain what I discovered Swamp Works to be. Swamp Works is a family of hardworking, dedicated, and driven people from various backgrounds and skill sets. These people all work to advance technologies and make science fiction science fact through means of rapid prototyping. They support and encourage failure as an option when learning new things, as long as lesson learned from said failure. In fact, their motto states "Fail, Fast, Forward." What this means is, not if but when one fails he or she must do so quickly and spring forward from the failure so that his or her progress is not delayed. With this acceptance, it provided me the confidence to dive into a multitude of projects working in various fields and with a wide range of skill sets. The first project I joined was Badger. My motivation for taking on this project was the opportunity I would have to obtain valuable experience working with 3D modeling and 3D printing technologies. Badger was a digging apparatus to be used in a highly dusty environment in a material known as Regolith. Regolith is a scientific term for the dirt or top soil found on planetary bodies. Regolith contains a large quantity of sediments less than lOppm and as a result poses a challenge of keeping it out of any cracks and crevices. Furthermore, regolith can create high levels of electrostatic energy, which can prove damaging to sensitive electrical hardware. With these characteristics in mind, I decided to take on the task of designing and manufacturing a dust proof cover for the sensitive electrical hardware. When I began this project, I did not have the slightest idea as to how to use 3D

  12. 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...

  13. 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...

  14. Developmental And Environmental History Of The Dismal Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Pollen analysis of several cores from the Dismal Swamp in southeastern Virginia have indicated that the swamp is a relatively young feature, having begun to develop...

  15. The role of Bahi swamp wetlands in enhancing household food ...

    African Journals Online (AJOL)

    The study was conducted to assess the role of Bahi swamp resources in enhancing household food security and income of adjacent communities. Specifically, the study assessed the socioeconomic activities in the swamp with a potential contribution to local livelihoods, the contribution of the swamp in enhancing ...

  16. 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.

  17. Studies on mangrove swamps of Goa 1. Heterotrophic bacterial flora from mangrove swamps

    Digital Repository Service at National Institute of Oceanography (India)

    Matondkar, S.G.P.; Mathani, S.; Mavinkurve, S.

    Heterotrophic bacterial flora from the mangrove swamps of Goa consisted of physiologically active organisms exhibiting cellulolytic, pectinolytic, amylolytic, proteolytic and H2S forming activities, throughout the year. Coryneform and Bacillus were...

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. Marsh and Water Management Plan Great Dismal Swamp National Wildlife Refuge 1990

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Many people perceive swamps as having standing water year-round. However, this is not the case in the Dismal Swamp, and, in fact, most swamp vegetation could not...

  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. Gulf-Wide Information System, Environmental Sensitivity Index Swamps, Geographic NAD83, LDWF (2001) [esi_swamp_LDWF_2001

    Data.gov (United States)

    Louisiana Geographic Information Center — This data set contains Environmental Sensitivity Index (ESI) swamps data of coastal Louisiana. The ESI is a classification and ranking system, which characterizes...

  6. 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

  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. Analysis of Technical Efficiency among Swamp Rice Farmers in ...

    African Journals Online (AJOL)

    This study was conducted to evaluate the Technical efficiency among swamp rice farmers in Niger State, Nigeria. A multi-stage sampling technique was used to select 159 swamp rice farmers. The data collected were analysed using descriptive statistics, and the stochastic frontier production function. The results showed ...

  10. Swamp Rice Production in Ogun Waterside Local Government Area ...

    African Journals Online (AJOL)

    In conclusion, efficiency and output in swamp rice production in the area can be increased by reducing the amount of labour used but increasing the quantity of seeds planted and adopting improved technologies such as improved seeds, agrochemicals, and fertilizer. Keywords: Agrochemical; fertilizers; swamp ric

  11. Microhabitat Characteristics of sites used by swamp rabbits

    Science.gov (United States)

    Patrick A. Zollner; Winston P. Smith; Leonard A. Brennan

    2000-01-01

    The swamp rabbit (Sylvilagus aquaticus) is one of the least studied North American lagomorphs; a better understanding of the habitat types it uses will improve management of this species. We studied microhabitat characteristics of sites associated with specific behaviors of the swamp rabbit. During spring-summer (15 April-1 October) and fall-winter (...

  12. Economic analysis of swamp rice production in Ebonyi Southern ...

    African Journals Online (AJOL)

    The aim of the paper is to analyze the determinants and profitability of the output of swamp rice farmers in Ebonyi southern Agricultural zone of Ebonyi State. Primary data were obtained through the use of structured questionnaires. A total of eighty (80) swamp rice farmers were randomly selected from the different blocks ...

  13. The scientific value and potential of New Zealand swamp kauri

    Science.gov (United States)

    Lorrey, Andrew M.; Boswijk, Gretel; Hogg, Alan; Palmer, Jonathan G.; Turney, Christian S. M.; Fowler, Anthony M.; Ogden, John; Woolley, John-Mark

    2018-03-01

    New Zealand swamp kauri (Agathis australis) are relic trees that have been buried and preserved in anoxic bog environments of northern New Zealand for centuries through to hundreds of millennia. Kauri are massive in proportion to other native New Zealand trees and they can attain ages greater than 1000 years. The export market for swamp (subfossil) kauri has recently been driven by demand for a high-value workable timber, but there are concerns about the sustainability of the remaining resource, a situation exacerbated in recent years by the rapid extraction of wood. Economic exploitation of swamp kauri presents several unique opportunities for Quaternary science, however the scientific value of this wood is not well understood by the wider research community and public. Here, we summarise the history of scientific research on swamp kauri, and explore the considerable potential of this unique resource. Swamp kauri tree-ring chronologies are temporally unique, and secondary analyses (such as radiocarbon and isotopic analyses) have value for improving our understanding of Earth's recent geologic history and pre-instrumental climate history. Swamp kauri deposits that span the last interglacial-glacial cycle show potential to yield "ultra-long" multi-millennia tree-ring chronologies, and composite records spanning large parts of MIS3 (and most of the Holocene) may be possible. High-precision radiocarbon dating of swamp kauri chronologies can improve the resolution of the global radiocarbon calibration curve, while testing age modelling and chronologic alignment of other independent long-term high-resolution proxy records. Swamp kauri also has the potential to facilitate absolute dating and verification of cosmogenic events found in long Northern Hemisphere tree-ring chronologies. Future efforts to conserve these identified values requires scientists to work closely with swamp kauri industry operators, resource consent authorities, and export regulators to mitigate

  14. 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.

  15. The fungal flora of the mangrove swamps of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Matondkar, S.G.P.; Mahtani, S.; Mavinkurve, S.

    Mangrove swamps of Goa (India) showed the presence of fungi belonging to 14 different genera, predominant ones being Monilia, Mucor, Syncephalastrum, Aspergillus and Trichothecium. Most of the isolates were found to be physiologically active...

  16. The Great Dismal Swamp National Wildlife Refuge Contaminants Monitoring Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Alternatives for an environmental contaminants monitoring plan have been developed for the Great Dismal Swamp National Wildlife Refuge (Refuge). This study...

  17. Panther Swamp National Wildlife Refuge : Hunting Plan and Controversy.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This collections covers Panther Swamp National Wildlife Refuge's hunting plan and memos (specifically Mike Espy) between the refuge on the local community. The local...

  18. Bond Swamp National Wildlife Refuge: Comprehensive Conservation Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan (CCP) was written to guide management on Bond Swamp NWR for the next 15 years. This plan outlines the Refuge vision and purpose...

  19. Forest Management Plan Great Dismal Swamp National Wildlife Refuge 1987

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The objectives of the timber management program at Great Dismal Swamp National Wildlife Refuge are: 1) protecting and preserving the unique and outstanding ecosystem...

  20. Hydrology Study at Great Swamp National Wildlife Refuge 1984

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This study evaluates the effects of changing land use on the water environment of the Great Swamp National Wildlife Refuge. Past, present and future land use maps...

  1. Ecotone Dynamics And Boundary Determination In The Great Dismal Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Data on hydrogeology, soils, and vegetation collected on four transects across the 48-km wetland-to-upland transition zone of the Great Dismal Swamp of Virginia/...

  2. The Natural And Cultural History Of The Great Dismal Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Great Dismal Swamp is a forested wetland located on the Middle Atlantic Coastal Plain in Southeastern Virginia and northeastern North Carolina. Estimates of the...

  3. Spiders of the Great Dismal Swamp: Lake Drummond 1977

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report outlines the results of a study of spiders that was conducted along the shores of Lake Drummond, in the Great Dismal Swamp. The purpose of the study was...

  4. Field Research on the Great Dismal Swamp Shrew 1988

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a progress report outlining the results of a study done on the evaluation of the distribution of the Dismal Swamp southeastern shrew in the refuge and areas...

  5. Animal Control Plan Great Swamp National Wildlife Refuge 1974

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Waterfowl production objectives for the Great Swamp National Wildlife Refuge are to create habitat supporting the production of 16,000 ducks and 500 geese annually....

  6. Panther Swamp National Wildlife Refuge Public Use Development Plan - 1985

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan for Panther Swamp NWR involves setting station public use goals, project a positive attitude, welcome and orient visitors, develop key resources awareness,...

  7. Late Pleistocene and Holocene History at Mubwindi Swamp, Southwest Uganda

    Science.gov (United States)

    Marchant, Robert; Taylor, David; Hamilton, Alan

    1997-05-01

    Deposits beneath Mubwindi Swamp provide a partial record of vegetation history since at least 43,000 yr ago. We studied pollen from two cores and obtained nine radiocarbon ages from one of these cores and three radiocarbon ages from the other. Pollen deposited before and soon after the last glacial maximum represents vegetation very different from the modern vegetation of the Mubwindi Swamp catchment. Although species now associated with higher altitudes were dominant some elements of moist lower montane forest persisted, possibly because of favorable soils or topography. The pollen data provides evidence for a late glacial montane forest refuge near Mubwindi Swamp. Moist lower montane forest became much more widespread soon after the glacial maximum. The only irrefutably Holocene sediments from Mubwindi Swamp date to the past 2500 yr. During this time a combination of climatic and human-induced changes in vegetation can be seen in the pollen records.

  8. Narrative Report : Great Swamp National Wildlife Refuges : January - December 1971

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Great Swamp National Wildlife Refuge outlines Refuge accomplishments during the 1971 calendar year. The report begins by summarizing...

  9. Great Swamp Wilderness Character Monitoring Back-end Database

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is the back-end data file for the Great Swamp Wilderness Character Monitoring Application. User interface and lookup databases are required for use (see...

  10. Safety Plan Great Dismal Swamp National Wildlife Refuge Suffolk, Virginia

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Great Dismal Swamp National Wildlife Refuge Safety Plan discusses policies for the safety of the station employees, volunteers, and public. This plan seeks to...

  11. Dismal Swamp National Wildlife Refuge Management Study Transmittal

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This study will investigate temporal and spatial variations in the concentrations of methane, nitrous oxide, hydrocarbons, and sulfur compounds in the Dismal Swamp....

  12. Mammals Of The Dismal Swamp: A Historical Account

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — For the first time, individual species of mammals of the Dismal Swamp area were considered in detail when K. A. Wilson studied the role of mink, otter, and raccoon...

  13. Annual Narrative 1967 Great Swamp National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Great Swamp National Wildlife Refuge outlines Refuge accomplishments during the 1967 calendar year. The report begins by summarizing...

  14. 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.

  15. Phosphate relationships in acid-sulphate soils of Mbiabet swamp ...

    African Journals Online (AJOL)

    Treatments consisted of potassium dihydrogen phosphate added to the swamp mud, cat-clay, and mud-clay in equal doses of 122 kg/ha P205, fitted into Latin square of 36 x 5 m swamp, except for the control plots. Limestone (CaC03) was applied to both fertilized and unfertilized plots at the rate of 50 kg/ha to reduce

  16. Regeneration potential of Taxodium distichum swamps and climate change

    Science.gov (United States)

    Middleton, B.A.

    2009-01-01

    Seed bank densities respond to factors across local to landscape scales, and therefore, knowledge of these responses may be necessary in forecasting the effects of climate change on the regeneration of species. This study relates the seed bank densities of species of Taxodium distichum swamps to local water regime and regional climate factors at five latitudes across the Mississippi River Alluvial Valley from southern Illinois to Louisiana. In an outdoor nursery setting, the seed banks of twenty-five swamps were exposed to non-flooded (freely drained) or flooded treatments, and the number and species of seeds germinating were recorded from each swamp during one growing season. Based on ANOVA analysis, the majority of dominant species had a higher rate of germination in non-flooded versus flooded treatments. Similarly, an NMS comparison, which considered the local water regime and regional climate of the swamps, found that the species of seeds germinating, almost completely shifted under non-flooded versus flooded treatments. For example, in wetter northern swamps, seeds of Taxodium distichum germinated in non-flooded conditions, but did not germinate from the same seed banks in flooded conditions. In wetter southern swamps, seeds of Eleocharis cellulosa germinated in flooded conditions, but did not germinate in non-flooded conditions. The strong relationship of seed germination and density relationships with local water regime and regional climate variables suggests that the forecasting of climate change effects on swamps and other wetlands needs to consider a variety of interrelated variables to make adequate projections of the regeneration responses of species to climate change. Because regeneration is an important aspect of species maintenance and restoration, climate drying could influence the species distribution of these swamps in the future. ?? 2008 Springer Science+Business Media B.V.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. 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...

  19. 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

  20. Benefits of Riverine Water Discharge into the Lorian Swamp, Kenya

    Directory of Open Access Journals (Sweden)

    Zipporah Musyimi

    2012-12-01

    Full Text Available Use and retention of river water in African highlands deprive communities in arid lowlands of their benefits. This paper reviews information on water use in the Ewaso Ng’iro catchment, Kenya, to evaluate the effects of upstream abstraction on the Lorian Swamp, a wetland used by pastoralists downstream. We first assess the abstractions and demands for water upstream and the river water supplies at the upper and the lower end of the Lorian Swamp. Further analysis of 12 years of monthly SPOT-VEGETATION satellite imagery reveals higher NDVI (Normalized Differential Vegetation Index values in the swamp than nearby rainfed areas, with the difference in NDVI between the two positively related to river water discharged into the swamp. The paper next reviews the benefits derived from water entering the swamp and the vulnerability to abstractions for three categories of water: (i the surface water used for drinking and sanitation; (ii the surface water that supports forage production; and (iii the water that recharges the Merti Aquifer. Our results suggest that benefits from surface water for domestic use and forage production are vulnerable to abstractions upstream whereas the benefits from the aquifer, with significant fossil water, are likely to be affected in the long run, but not the short term.

  1. 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

  2. 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...

  3. 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)

  4. 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

  5. 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.

  6. 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....

  7. 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...

  8. 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

  9. 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...

  10. Status Survey for the Dismal Swamp- Green Stink Bug (Chlorochroa dismalia) in Virginia

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Dismal Swamp green stink bug (Chlorochroa dismalia), also known as the Dismal Swamp chlorochroan bug, is one of 52 members of the Family Pentatomidae (Order...

  11. Penaeid prawn population and fry resource in a mangrove swamp of Goa, India

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.; Nair, S.R.S.

    Penaeid prawns abundantly occur in the mangrove swamp during the premonsoon season. They are constituted by the commercial species, Penaeus merguiensis, Metapenaeus dobsoni and M. monoceros. Recruitment of the swamp takes place when the individuals...

  12. 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.

  13. 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...

  14. COMPLEX STUDY OF THE LACUSTRIAN ECOSYSTEMS OF MOHOŞ SWAMP

    Directory of Open Access Journals (Sweden)

    Daniel Constantin DIACONU

    2010-06-01

    Full Text Available Mohoş Swamp is an oligotroph swamp, formed in a volcanic crater on the site of a former lake, which permanently changes. Using a series of modern methods such as ultrasound bathymetry, we want to set up a reference base so that in the future one can be able to determine the rhythm and direction of the development of this complex ecosystem, both in terms of morph metrics and chemical hydrology parameters point of view. Bathymetry and geomorfological study represents the most important stage because it makes it possible to establish the concrete characteristics of the investigated lakes as well as their placement.

  15. 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....

  16. 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...

  17. 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.

  18. 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.

  19. Characteristics of mangrove swamps managed for mosquito control in eastern Florida, USA

    Science.gov (United States)

    Middleton, B.; Devlin, D.; Proffitt, E.; McKee, K.; Cretini, K.F.

    2008-01-01

    Manipulations of the vegetation and hydrology of wetlands for mosquito control are common worldwide, but these modifications may affect vital ecosystem processes. To control mosquitoes in mangrove swamps in eastern Florida, managers have used rotational impoundment management (RIM) as an alternative to the worldwide practice of mosquito ditching. Levees surround RIM swamps, and water is pumped into the impoundment during the summer, a season when natural swamps have low water levels. In the New World, these mosquito-managed swamps resemble the mixed basin type of mangrove swamp (based on PCA analysis). An assessment was made of RIM, natural (control), and breached-RIM (restored) swamps in eastern Florida to compare their structural complexities, soil development, and resistance to invasion. Regarding structural complexity, dominant species composition differed between these swamps; the red mangrove Rhizophora mangle occurred at a higher relative density in RIM and breached-RIM swamps, and the black mangrove Avicennia germinans had a higher relative density in natural swamps. Tree density and canopy cover were higher and tree height lower in RIM swamps than in natural and breached-RIM swamps. Soil organic matter in RIM swamps was twice that in natural or breached-RIM swamps. RIM swamps had a lower resistance to invasion by the Brazilian pepper tree Schinus terebinthifolius, which is likely attributable to the lower porewater salinity in RIM swamps. These characteristics may reflect differences in important ecosystem processes (primary production, trophic structure, nutrient cycling, decomposition). Comparative assessments of managed wetlands are vital for land managers, so that they can make informed decisions compatible with conservation objectives. ?? Inter-Research 2008.

  20. The White Cedar of the Dismal Swamp 1923

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a report that discusses the various uses, yields and properties of the White Cedar in the Great Dismal Swamp area in the early 1920s. It also discusses the...

  1. Invertebrate Encrustations On The Mangrove Swamp Oyster And ...

    African Journals Online (AJOL)

    The mangrove swamp oyster Crassostrea tulipa demonstrates a symbiotic relationship with the barnacle. Balnus sp and other encrusting invertebrates. It is inferred that the latter militate against predatory drilling on the oyster by Thais califera as well as prevent algal infestation and the consequent bioerosion by herbivorous ...

  2. Swamp Rice Production in Ogun Waterside Local Government Area ...

    African Journals Online (AJOL)

    All the variable inputs were inefficiently utilized and about 85% of the variations in rice output could be explained by factors included in the regression model. In conclusion, efficiency and output in swamp rice production in the area can be increased by reducing the amount of labour used but increasing the quantity of seeds ...

  3. Distribution of periphytic algae in wetlands (Palm swamps, Cerrado), Brazil.

    Science.gov (United States)

    Dunck, B; Nogueira, I S; Felisberto, S A

    2013-05-01

    The distribution of periphytic algae communities depends on various factors such as type of substrate, level of disturbance, nutrient availability and light. According to the prediction that impacts of anthropogenic activity provide changes in environmental characteristics, making impacted Palm swamps related to environmental changes such as deforestation and higher loads of nutrients via allochthonous, the hypothesis tested was: impacted Palm swamps have higher richness, density, biomass and biovolume of epiphytic algae. We evaluated the distribution and structure of epiphytic algae communities in 23 Palm swamps of Goiás State under different environmental impacts. The community structure attributes here analyzed were composition, richness, density, biomass and biovolume. This study revealed the importance of the environment on the distribution and structuration of algal communities, relating the higher values of richness, biomass and biovolume with impacted environments. Acidic waters and high concentration of silica were important factors in this study. Altogether 200 taxa were identified, and the zygnemaphycea was the group most representative in richness and biovolume, whereas the diatoms, in density of studied epiphyton. Impacted Palm swamps in agricultural area presented two indicator species, Gomphonema lagenula Kützing and Oedogonium sp, both related to mesotrophic to eutrophic conditions for total nitrogen concentrations of these environments.

  4. Aluminum and iron contents in phosphate treated swamp rice farm ...

    African Journals Online (AJOL)

    In 2006 aluminum and iron contents were determined in phosphate treated swamp rice farm of Mbiabet, Akwa Ibom State. The objectives were to determine the aluminum and iron contents, the effect of drying, phosphate and lime application in an acid sulphate soil grown to rice in Nigeria. The soil samples used were ...

  5. Swamp tours in Louisiana post Hurricane Katrina and Hurricane Rita

    Science.gov (United States)

    Dawn J. Schaffer; Craig A. Miller

    2007-01-01

    Hurricanes Katrina and Rita made landfall in southern Louisiana during August and September 2005. Prior to these storms, swamp tours were a growing sector of nature-based tourism that entertained visitors while teaching about local flora, fauna, and culture. This study determined post-hurricane operating status of tours, damage sustained, and repairs made. Differences...

  6. Production Efficiency of Swamp Rice Production in Cross River ...

    African Journals Online (AJOL)

    397.00k with N9.80K made on every naira invested in improved variety of swamp rice produced in the study area. Rice farming business is a profitable business, with attractive net return on investment. Therefore, unemployed youths in Cross River ...

  7. 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

  8. 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

  9. 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.

  10. 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

  11. 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...

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. Diet of Lontra longicaudis (Olfers, 1818 (Carnivora: Mustelidae in three limnic systems in Southern Rio Grande do Sul State, Brazil

    Directory of Open Access Journals (Sweden)

    Fernando Marques Quintela

    2012-12-01

    Full Text Available The aim of the present work was to study the diet of Lontra longicaudis in three limnic systems (anthropogenic shallow lakes, pluvial channel and coastal stream in Rio Grande do Sul State coastal plain, southern Brazil. Fishes were the most consumed item in all the three systems, being Mugilidae the most representative family in the pluvial channel and coastal stream and Cichlidae in the shallow lakes. Other identified items were mollusks, insects, crustaceans, amphibians, reptiles, birds and mammals and vegetal fragments. The high frequency of birds in the shallow lakes was remarkable, considering the lower frequencies of this item in previous investigations on the species diet. There was a high frequency of swamp eels (Synbranchidae, Synbranchus marmoratus in the pluvial channel and shallow lakes, which were usually absent or found in low frequencies in previous studies.

  17. 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.

  18. 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....

  19. 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.

  20. 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...

  1. The exploitation of swamp plants for dewatering liquid sewage sludge

    Directory of Open Access Journals (Sweden)

    Jiří Šálek

    2006-01-01

    Full Text Available The operators of little rural wastewater treatment plants have been interested in economic exploitation of sewage sludge in local conditions. The chance is searching simply and natural ways of processing and exploitation stabilized sewage sludge in agriculture. Manure substrate have been obtained by composting waterless sewage sludge including rest plant biomass after closing 6–8 years period of filling liquid sewage sludge to the basin. Main attention was focused on exploitation of swamp plants for dewatering liquid sewage sludge and determination of influence sewage sludge on plants, intensity and course of evapotranspiration and design and setting of drying beds. On the base of determined ability of swamp plants evapotranspiration were edited suggestion solutions of design and operation sludge bed facilities in the conditions of small rural wastewater treatment plant.

  2. Forest Dynamics of Peat Swamp Forest in Sebangau, Central Kalimantan

    Directory of Open Access Journals (Sweden)

    EDI MIRMANTO

    2009-10-01

    Full Text Available Forest dynamics were studied from 1999 to 2001 for individuals > 15 cm in girth of 24 most common species in six 0.25-ha plots. The plots were set up in natural peat swamp forest in the upper catchments of Sebangau, Central Kalimantan. Aim of the study is to understand the dynamics and vegetation changes of forest studied during period of study. The peat swamp forest in the study site might be categorized as moderately forest dynamic in term of rate of growth, mortality and recruitment. Annual relative growth rate and mortality rate was comparable to previous study but recruitment rate relatively higher. There was significant effect of diameter class on annual growth rate, but not to mortality rate. Even not too strong two environment factors (peat depth and distance to river were significant correlated with rate of mortality and recruitment. During two-year period study there was no significant changes in vegetation structure.

  3. 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.

  4. Mating system and the critical migration rate for swamping selection.

    Science.gov (United States)

    Hu, Xin-Sheng

    2011-06-01

    Crow et al. (1990) and Barton (1992) have examined the critical migration rate for swamping selection in the nuclear system. Here, I use the same methodology to examine the critical migration rate in the cytonuclear system for hermaphrodite plants with a mixed mating system. Two selection schemes for a nuclear gene (heterozygote disadvantage and directional selection) and the directional selection scheme for organelle genes are considered. Results show that under random mating, the previous results are applicable to plant species by appropriate re-parameterization of the migration rate for nuclear and paternal organelle genes. A simple complementary relationship exists between seed and pollen flow in contributing to the critical migration rate. Under the mixed mating system, the critical migration rate of seeds and pollen for nuclear and paternal organelle genes can be changed due to the effects of selection and the cytonuclear linkage disequilibrium generated by migration and inbreeding. A negative but not complementary relationship exists between seed and pollen flow in contributing to the critical migration rate, varying with the mating system. Partial selfing can also adjust the critical seed flow for the maternal organelle gene, with a small critical migration rate for species of a high selfing rate. Both concordance and discordance among cytonuclear genes can occur under certain conditions during the process of swamping selection. This theory predicts the presence of various contributions of seed versus pollen flow to genetic swamping for plants with diverse mating systems.

  5. 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....

  6. 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...

  7. 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

  8. 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...

  9. 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...

  10. 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

  11. 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...

  12. 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.

  13. 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...

  14. 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 ...

  15. 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

  16. 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

  17. 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...

  18. 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...

  19. 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...

  20. 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....

  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. 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

  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. 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 ...

  5. 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...

  6. 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...

  7. 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.

  8. 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

  9. 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.

  10. Wastewater treatment by a natural wetland: the Nakivubo Swamp Uganda: processes and implications

    NARCIS (Netherlands)

    Kansiime, F.; Nalubega, N.

    1999-01-01

    The Nakivubo swamp is located in Uganda, near its capital Kampala, and has been receiving wastewater from Kampala for over 30 years. This swamp consists of a floating root mat co-dominated by the sedges Cyperus papyrus and Miscanthidium violaceum. Tbe partially treated wastewater mostly flows

  11. Operational restoration of the Pen Branch bottomland hardwood and swamp wetlands - the research setting

    Science.gov (United States)

    Eric A. Nelson; Neil C. Dulohery; Randall K. Kolka; William H. McKee

    2000-01-01

    The Savannah River swamp, a 3020 ha forested wetland on the floodplain of the Savannah River, USA is located on the Department of Energy's Savannah River site (SRS) near Aiken, SC. Historically, the swamp consisted of approximately 50% bald cypress-water tupelo (Taxodium distichum-Nyssa aquatica) stands, 40% mixed bottomland hardwood stands, and...

  12. Influence of Soil Type and Drainage on Growth of Swamp Chestnut Oak (Quercus Michauxii Nutt.) Seedlings

    Science.gov (United States)

    Donald D. Hook

    1969-01-01

    Swamp chestnut oak (Quercus michauxii Nutt.) seedlings were grown for 2 years in five soil types in drained and undrained pots. First-year height growth was related to soil type and pot drainage, but second-year height growth was related only to soil type. Results suggest that swamp chestnut oak is site-sensitive. But slow growth, a maximum of 2...

  13. Wastewater treatment by a natural wetland: the Nakivubo swamp, Uganda : processes and implications

    NARCIS (Netherlands)

    Kansiime, F.; Nalubega, M.

    1999-01-01

    An investigation to assess the capacity of the Nakivubo swamp, Kampala-Uganda (which has been receiving partially treated sewage from the city for more than 30 years now), to remove nutrients and pathogens was carried out. The aim of the study was to evaluate the potential of this swamp to

  14. 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...

  15. 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...

  16. Vegetation analyses of Sebangau peat swamp forest, Central Kalimantan

    Directory of Open Access Journals (Sweden)

    EDI MIRMANTO

    2010-04-01

    Full Text Available Mirmanto E (2010 Vegetation analyses of Sebangau peat swamp forest, Central Kalimantan. Biodiversitas 11: 82-88. The vegetation analysis study has been made in Sebangau peat-swamp forest, Central Kalimantan. Eight permanent plots of 50-m x 50-m were set-up distribute from close to the river with shallow peat-layer up to the inland with relatively deep peat-layer. Enumeration of trees (GBH > 15 cm was conducted in all of 8 plots. Overall there are 133 species (taxa were recorded within 8 plots belong to 34 families where Dipterocarpaceae, Clusiaceae, Myrtaceae and Sapotaceae were the most dominant family. Out of all species recorded, Combretocarpus rotundatus, Palaquium leiocarpum, Stemonurus scorpioides and Tristania whittiana were the most dominant species. Two community’s types namely Combretocarpus rotundatus-Shorea balangeran community and Palaquium leiocarpum-Eugenia densinervium community were recognized and they distributed in slightly different habitat condition. The sequence of these two communities’ shows significantly related to both distances to river and peat-depth. In addition there was indication the presence of habitat preference among tree species.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. A carbon balance model for the great dismal swamp ecosystem.

    Science.gov (United States)

    Sleeter, Rachel; Sleeter, Benjamin M; Williams, Brianna; Hogan, Dianna; Hawbaker, Todd; Zhu, Zhiliang

    2017-12-01

    Carbon storage potential has become an important consideration for land management and planning in the United States. The ability to assess ecosystem carbon balance can help land managers understand the benefits and tradeoffs between different management strategies. This paper demonstrates an application of the Land Use and Carbon Scenario Simulator (LUCAS) model developed for local-scale land management at the Great Dismal Swamp National Wildlife Refuge. We estimate the net ecosystem carbon balance by considering past ecosystem disturbances resulting from storm damage, fire, and land management actions including hydrologic inundation, vegetation clearing, and replanting. We modeled the annual ecosystem carbon stock and flow rates for the 30-year historic time period of 1985-2015, using age-structured forest growth curves and known data for disturbance events and management activities. The 30-year total net ecosystem production was estimated to be a net sink of 0.97 Tg C. When a hurricane and six historic fire events were considered in the simulation, the Great Dismal Swamp became a net source of 0.89 Tg C. The cumulative above and below-ground carbon loss estimated from the South One and Lateral West fire events totaled 1.70 Tg C, while management activities removed an additional 0.01 Tg C. The carbon loss in below-ground biomass alone totaled 1.38 Tg C, with the balance (0.31 Tg C) coming from above-ground biomass and detritus. Natural disturbances substantially impact net ecosystem carbon balance in the Great Dismal Swamp. Through alternative management actions such as re-wetting, below-ground biomass loss may have been avoided, resulting in the added carbon storage capacity of 1.38 Tg. Based on two model assumptions used to simulate the peat system, (a burn scar totaling 70 cm in depth, and the soil carbon accumulation rate of 0.36 t C/ha -1 /year -1 for Atlantic white cedar), the total soil carbon loss from the South One and Lateral West fires

  2. A carbon balance model for the great dismal swamp ecosystem

    Directory of Open Access Journals (Sweden)

    Rachel Sleeter

    2017-01-01

    Full Text Available Abstract Background Carbon storage potential has become an important consideration for land management and planning in the United States. The ability to assess ecosystem carbon balance can help land managers understand the benefits and tradeoffs between different management strategies. This paper demonstrates an application of the Land Use and Carbon Scenario Simulator (LUCAS model developed for local-scale land management at the Great Dismal Swamp National Wildlife Refuge. We estimate the net ecosystem carbon balance by considering past ecosystem disturbances resulting from storm damage, fire, and land management actions including hydrologic inundation, vegetation clearing, and replanting. Results We modeled the annual ecosystem carbon stock and flow rates for the 30-year historic time period of 1985–2015, using age-structured forest growth curves and known data for disturbance events and management activities. The 30-year total net ecosystem production was estimated to be a net sink of 0.97 Tg C. When a hurricane and six historic fire events were considered in the simulation, the Great Dismal Swamp became a net source of 0.89 Tg C. The cumulative above and below-ground carbon loss estimated from the South One and Lateral West fire events totaled 1.70 Tg C, while management activities removed an additional 0.01 Tg C. The carbon loss in below-ground biomass alone totaled 1.38 Tg C, with the balance (0.31 Tg C coming from above-ground biomass and detritus. Conclusions Natural disturbances substantially impact net ecosystem carbon balance in the Great Dismal Swamp. Through alternative management actions such as re-wetting, below-ground biomass loss may have been avoided, resulting in the added carbon storage capacity of 1.38 Tg. Based on two model assumptions used to simulate the peat system, (a burn scar totaling 70 cm in depth, and the soil carbon accumulation rate of 0.36 t C/ha−1/year−1 for Atlantic white cedar, the total

  3. A carbon balance model for the great dismal swamp ecosystem

    Science.gov (United States)

    Sleeter, Rachel; Sleeter, Benjamin M.; Williams, Brianna; Hogan, Dianna; Hawbaker, Todd J.; Zhu, Zhiliang

    2017-01-01

    BackgroundCarbon storage potential has become an important consideration for land management and planning in the United States. The ability to assess ecosystem carbon balance can help land managers understand the benefits and tradeoffs between different management strategies. This paper demonstrates an application of the Land Use and Carbon Scenario Simulator (LUCAS) model developed for local-scale land management at the Great Dismal Swamp National Wildlife Refuge. We estimate the net ecosystem carbon balance by considering past ecosystem disturbances resulting from storm damage, fire, and land management actions including hydrologic inundation, vegetation clearing, and replanting.ResultsWe modeled the annual ecosystem carbon stock and flow rates for the 30-year historic time period of 1985–2015, using age-structured forest growth curves and known data for disturbance events and management activities. The 30-year total net ecosystem production was estimated to be a net sink of 0.97 Tg C. When a hurricane and six historic fire events were considered in the simulation, the Great Dismal Swamp became a net source of 0.89 Tg C. The cumulative above and below-ground carbon loss estimated from the South One and Lateral West fire events totaled 1.70 Tg C, while management activities removed an additional 0.01 Tg C. The carbon loss in below-ground biomass alone totaled 1.38 Tg C, with the balance (0.31 Tg C) coming from above-ground biomass and detritus.ConclusionsNatural disturbances substantially impact net ecosystem carbon balance in the Great Dismal Swamp. Through alternative management actions such as re-wetting, below-ground biomass loss may have been avoided, resulting in the added carbon storage capacity of 1.38 Tg. Based on two model assumptions used to simulate the peat system, (a burn scar totaling 70 cm in depth, and the soil carbon accumulation rate of 0.36 t C/ha−1/year−1 for Atlantic white cedar), the total soil carbon loss from the

  4. 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.

  5. THE DISTRIBUTION AND BIODIVERSITY OF FISHES IN LEBAK PAMPANGAN SWAMP SOUTH SUMATRA PROVINCE

    Directory of Open Access Journals (Sweden)

    Dina Muthmainah

    2013-12-01

    Full Text Available This research was conducted to evaluate the fish distribution and biodiversity within three types of swamp ecosystem with different water sources in Pampangan Sub-district during July to December 2011. The field observation were conducted in three different types of swamp. Ecological data and samples were collected from three sampling points in each swamp type. Parameters including local distribution, diversity index, similarity index, evenness and species richness, were analyzed. The results show a number of 9,723 fishes corresponding to 46 species were collected, the fish categorized into 16 families belonging to five orders. Eight species were found in all type of swamps i.e. Mystus nemurus, Channa striata, Cyclocheilchthys apogon, Cyclocheilichthys armatus, Pristolepis fasciata, Puntius lineatus, Osteochillus hasselti, and Trichogaster pectoralis. A diversity index of fishes in Pampangan Swamp ranged from 2.31 to 2.85, indicating moderate values. The evenness index was high more than 50%. The highest similarity was found between type 1 and type 3 of (0.43. The highest diversity index (2.85 found in type 2 of swamp indicates the swamp in more stable condition.

  6. Food Swamps Predict Obesity Rates Better Than Food Deserts in the United States.

    Science.gov (United States)

    Cooksey-Stowers, Kristen; Schwartz, Marlene B; Brownell, Kelly D

    2017-11-14

    This paper investigates the effect of food environments, characterized as food swamps, on adult obesity rates. Food swamps have been described as areas with a high-density of establishments selling high-calorie fast food and junk food, relative to healthier food options. This study examines multiple ways of categorizing food environments as food swamps and food deserts, including alternate versions of the Retail Food Environment Index. We merged food outlet, sociodemographic and obesity data from the United States Department of Agriculture (USDA) Food Environment Atlas, the American Community Survey, and a commercial street reference dataset. We employed an instrumental variables (IV) strategy to correct for the endogeneity of food environments (i.e., that individuals self-select into neighborhoods and may consider food availability in their decision). Our results suggest that the presence of a food swamp is a stronger predictor of obesity rates than the absence of full-service grocery stores. We found, even after controlling for food desert effects, food swamps have a positive, statistically significant effect on adult obesity rates. All three food swamp measures indicated the same positive association, but reflected different magnitudes of the food swamp effect on rates of adult obesity (p values ranged from 0.00 to 0.16). Our adjustment for reverse causality, using an IV approach, revealed a stronger effect of food swamps than would have been obtained by naïve ordinary least squares (OLS) estimates. The food swamp effect was stronger in counties with greater income inequality (p food outlets and incentivizing healthy food retailers to locate in underserved neighborhoods warrant consideration as strategies to increase health equity.

  7. Food Swamps Predict Obesity Rates Better Than Food Deserts in the United States

    Directory of Open Access Journals (Sweden)

    Kristen Cooksey-Stowers

    2017-11-01

    Full Text Available This paper investigates the effect of food environments, characterized as food swamps, on adult obesity rates. Food swamps have been described as areas with a high-density of establishments selling high-calorie fast food and junk food, relative to healthier food options. This study examines multiple ways of categorizing food environments as food swamps and food deserts, including alternate versions of the Retail Food Environment Index. We merged food outlet, sociodemographic and obesity data from the United States Department of Agriculture (USDA Food Environment Atlas, the American Community Survey, and a commercial street reference dataset. We employed an instrumental variables (IV strategy to correct for the endogeneity of food environments (i.e., that individuals self-select into neighborhoods and may consider food availability in their decision. Our results suggest that the presence of a food swamp is a stronger predictor of obesity rates than the absence of full-service grocery stores. We found, even after controlling for food desert effects, food swamps have a positive, statistically significant effect on adult obesity rates. All three food swamp measures indicated the same positive association, but reflected different magnitudes of the food swamp effect on rates of adult obesity (p values ranged from 0.00 to 0.16. Our adjustment for reverse causality, using an IV approach, revealed a stronger effect of food swamps than would have been obtained by naïve ordinary least squares (OLS estimates. The food swamp effect was stronger in counties with greater income inequality (p < 0.05 and where residents are less mobile (p < 0.01. Based on these findings, local government policies such as zoning laws simultaneously restricting access to unhealthy food outlets and incentivizing healthy food retailers to locate in underserved neighborhoods warrant consideration as strategies to increase health equity.

  8. Food Swamps Predict Obesity Rates Better Than Food Deserts in the United States

    Science.gov (United States)

    Cooksey-Stowers, Kristen; Schwartz, Marlene B.; Brownell, Kelly D.

    2017-01-01

    This paper investigates the effect of food environments, characterized as food swamps, on adult obesity rates. Food swamps have been described as areas with a high-density of establishments selling high-calorie fast food and junk food, relative to healthier food options. This study examines multiple ways of categorizing food environments as food swamps and food deserts, including alternate versions of the Retail Food Environment Index. We merged food outlet, sociodemographic and obesity data from the United States Department of Agriculture (USDA) Food Environment Atlas, the American Community Survey, and a commercial street reference dataset. We employed an instrumental variables (IV) strategy to correct for the endogeneity of food environments (i.e., that individuals self-select into neighborhoods and may consider food availability in their decision). Our results suggest that the presence of a food swamp is a stronger predictor of obesity rates than the absence of full-service grocery stores. We found, even after controlling for food desert effects, food swamps have a positive, statistically significant effect on adult obesity rates. All three food swamp measures indicated the same positive association, but reflected different magnitudes of the food swamp effect on rates of adult obesity (p values ranged from 0.00 to 0.16). Our adjustment for reverse causality, using an IV approach, revealed a stronger effect of food swamps than would have been obtained by naïve ordinary least squares (OLS) estimates. The food swamp effect was stronger in counties with greater income inequality (p food outlets and incentivizing healthy food retailers to locate in underserved neighborhoods warrant consideration as strategies to increase health equity. PMID:29135909

  9. SWAMP+: multiple subsequence alignment using associative massive parallelism

    Energy Technology Data Exchange (ETDEWEB)

    Steinfadt, Shannon Irene [Los Alamos National Laboratory; Baker, Johnnie W [KENT STATE UNIV.

    2010-10-18

    A new parallel algorithm SWAMP+ incorporates the Smith-Waterman sequence alignment on an associative parallel model known as ASC. It is a highly sensitive parallel approach that expands traditional pairwise sequence alignment. This is the first parallel algorithm to provide multiple non-overlapping, non-intersecting subsequence alignments with the accuracy of Smith-Waterman. The efficient algorithm provides multiple alignments similar to BLAST while creating a better workflow for the end users. The parallel portions of the code run in O(m+n) time using m processors. When m = n, the algorithmic analysis becomes O(n) with a coefficient of two, yielding a linear speedup. Implementation of the algorithm on the SIMD ClearSpeed CSX620 confirms this theoretical linear speedup with real timings.

  10. Weeds optimally grow in peat swamp after burning

    Directory of Open Access Journals (Sweden)

    P.D. Susanti

    2014-07-01

    Full Text Available After clearing land by burning the peat, then the weeds and undergrowth will flourish. Even sometimes, the weeds are eventually burned again. Weed is known as a destroyer plant that has to be controlled. Through proper treatment, the existing weeds in peatlands can be potentiallly exploited. The purpose of this study was to determine the calorific value of briquettes as one of peatland weeds utilization. The results showed that the calorific value ranged from 2,492 cal/g to 5,230 cal/g. The lowest calorific value was on ‘teki kecil’ grass (Scirpus grossus Lf, while the highest calorific value was observed for ‘bantalaki grass’ (Hymenachne amplexicaulis Nees. The high calorific value of the peat weeds are potential for biomass briquettes raw materials. The utilization and use of peat weed briquettes as a raw materials expected can reduce land degradation due to peat swamp burning

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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...

  16. 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...

  17. 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.

  18. 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.

  19. 75 FR 41879 - Great Swamp National Wildlife Refuge, Morris County, NJ

    Science.gov (United States)

    2010-07-19

    ... refuge, contact William Koch, Refuge Manager, at Great Swamp NWR, 241 Pleasant Plains Road, Basking Ridge... listed endangered Indiana bats are known to occur on the refuge. Reptile and amphibian species of...

  20. A Contribution towards a Vascular Flora of the Great Dismal Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This flora is an enumeration of the vascular plants growing without cultivation in the Great Dismal Swamp. It is hoped that this work will be of value to the rapidly...

  1. Final Environmental Impact Statement For The Great Dismal Swamp National Wildlife Refuge Master Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Great Dismal Swamp Refuge Master Plan guides the long-range development of the Refuge by identifying and integrating appropriate habitats, management strategies,...

  2. Swainson’s Warbler And the Cowbird In The Dismal Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Swainson's Warbler, Limnothlypis swainsonii , is a fairly common breeding bird in the Dismal Swamp of Virginia and North Carolina where it is near the northern limit...

  3. A Report Concerning the Soils of a Portion of the Okefenokee Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document contains description of vegetation and organic and mineral soil of the Okefenokee Swamp. This report covers the investigations made on a tract of the...

  4. Environmental Impact Statement Master Plan Great Dismal Swamp National Wildlife Refuge 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The following report describes the proposed master plan for long range management and development of Great Dismal Swamp National Wildlife Refuge and compares the...

  5. Water Control System In The Great Dismal Swamp National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Reference is made to your letter of 21 September 1977, requesting a description of the water control system in the Great Dismal Swamp National Wildlife Refuge....

  6. Developmental History and Ecology of the Dismal Swamp with Recommendations for Public Ownership and Management 1974

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The report discusses the development and history of the Dismal Swamp and proposes the designation of a Research Natural Area. Management and research needs are...

  7. Peat deposits Of Dismal Swamp Pocosins, Camdem, Currituck, Gates, Pasquotank, And Perquimans Counties, North Carolina

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Peat is present in the Dismal Swamp of northeastern North Carolina and southeastern Virginia. In North Carolina the peat is in 4 separate deposits located west,...

  8. Great Swamp National Wildlife Refuge: Annual narrative report: Calendar year 1991

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Great Swamp National Wildlife Refuge outlines Refuge accomplishments during the 1991 calendar year. The report begins with a summary...

  9. Great Swamp National Wildlife Refuge: Annual narrative report: Calendar year 1988

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Great Swamp National Wildlife Refuge outlines Refuge accomplishments during the 1988 calendar year. The report begins with a summary...

  10. Notes On The Amphibians And Reptiles Of The Great Dismal Swamp Of Virginia And North Carolina

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Great Dismal Swamp encompasses approximately 200,000 acres in southeastern Virginia and northeastern North Carolina. As with this paper, most of the published...

  11. Aerial Orthophotography, Interpretation and Forest Type Mapping on Great Dismal Swamp NWR.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Sewall forest typing services for the Northern portion of Great Dismal Swamp NWR in northeastern North Carolina. This includes complete new aerial photography and...

  12. Great Swamp National Wildlife Refuge: Annual narrative report: Calendar year 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Great Swamp National Wildlife Refuge outlines Refuge accomplishments during the 1989 calendar year. The report begins with a summary...

  13. Great Dismal Swamp National Wildlife Refuge FY 1994 Prescribed Fire Proposal Plan Remnant Marsh

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan considers fire on Great Dismal Swamp National Wildlife Refuge as a tool for management and as a potential problem to be dealt with. This document discusses...

  14. Great Swamp National Wildlife Refuge: Annual narrative report: Calendar year 1992

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Great Swamp National Wildlife Refuge outlines Refuge accomplishments during the 1992 calendar year. The report begins with a summary...

  15. Great Swamp National Wildlife Refuge: Annual narrative report: Calendar year 1990

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Great Swamp National Wildlife Refuge outlines Refuge accomplishments during the 1990 calendar year. The report begins with a summary...

  16. Great Dismal Swamp National Wildlife Refuge : Annual narrative report: Calendar year 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Great Dismal Swamp National Wildlife Refuge outlines Refuge accomplishments during the 1986 calendar year. The report begins with a...

  17. Assessment of mercury contamination in bats at the Great Dismal Swamp National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — While bats at the Great Dismal Swamp National Wildlife Refuge (GDSNWR) have relatively low mean blood and fur Hg concentrations compared to point source...

  18. A survey of contaminants in the Great Dismal Swamp National Wildlife Refuge, Virginia

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A contaminant survey was conducted in the Great Dismal Swamp National Wildlife Refuge to determine the extent of contamination entering the Refuge from sources near...

  19. Great Dismal Swamp National Wildlife Refuge: Annual narrative report: Calendar year 1992

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Great Dismal Swamp National Wildlife Refuge outlines Refuge accomplishments during the 1992 calendar year. The report begins with a...

  20. Synopsis Of Planning Needs And Issues Great Dismal Swamp National Wildlife Refuge Master Plan January, 1982

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Great Dismal Swamp Master Plan guides the long-range development of the Refuge by identifying and integrating appropriate habitats, management strategies,...

  1. 75 FR 8107 - Bond Swamp National Wildlife Refuge, Bibb and Twiggs Counties, GA

    Science.gov (United States)

    2010-02-23

    ... for hunting, fishing, wildlife observation/photography, environmental education/interpretation... opportunities for hunting, fishing, wildlife observation, wildlife photography, and environmental education and... impact (FONSI) for the environmental assessment for Bond Swamp National Wildlife Refuge (NWR). In the...

  2. Influence Of Species, Season, And Soil On Foliar Macronutrients In The Great Dismal Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Leaf macronutrient variation was studied in four plant communities in the Dismal Swamp of Virginia. Soils and species composition differed markedly between sites....

  3. Great Dismal Swamp National Wildlife Refuge: Annual narrative report: Calendar year 1990

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Great Dismal Swamp National Wildlife Refuge outlines Refuge accomplishments during the 1990 calendar year. The report begins with a...

  4. Great Dismal Swamp National Wildlife Refuge : Annual narrative report: Calendar year 1987

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Great Dismal Swamp National Wildlife Refuge outlines Refuge accomplishments during the 1987 calendar year. The report begins with a...

  5. Annual Water Management Program Great Dismal Swamp National Wildlife Refuge 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The management objectives discussed in this report are: 1) To improve and better interpret the hydrologic and vegetative databases for the Great Dismal swamp, 2) To...

  6. Great Dismal Swamp National Wildlife Refuge: Annual narrative report: Calendar year 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Great Dismal Swamp National Wildlife Refuge outlines Refuge accomplishments during the 1989 calendar year. The report begins with a...

  7. Annual Water Management Program Great Dismal Swamp National Wildlife Refuge 1991

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The management objectives discussed in this report are: 1) To improve and better interpret the hydrologic and vegetative databases for the Great Dismal swamp, 2) To...

  8. Public Use Plan Great Dismal Swamp National Wildlife Refuge October 1990

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Great Dismal Swamp Refuge Master Plan guides the long-range development of the Refuge by identifying and integrating appropriate habitats, management strategies,...

  9. Great Dismal Swamp National Wildlife Refuge: Annual narrative report: Calendar year 1998

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Great Dismal Swamp National Wildlife Refuge outlines Refuge accomplishments during the 1998 calendar year. The report begins with a...

  10. A Water Budget and Water Quality Study of the Dismal Swamp Thesis Proposal

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The main objective of this project is to determine the change in water quality throughout a section of the Dismal Swamp and to calculate the water budget for the...

  11. 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.

  12. 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.

  13. 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.

  14. 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...

  15. Wastewater treatment by a natural wetland: the Nakivubo swamp, Uganda : processes and implications

    OpenAIRE

    Kansiime, F.; Nalubega, M.

    1999-01-01

    An investigation to assess the capacity of the Nakivubo swamp, Kampala-Uganda (which has been receiving partially treated sewage from the city for more than 30 years now), to remove nutrients and pathogens was carried out. The aim of the study was to evaluate the potential of this swamp to remove nutrients and pathogens from wastewater in a sustainable way, with emphasis on describing and quantifying their pathways, transformations and budgets.

    From field studies, water balan...

  16. The Ecology of Rawa Aopa, a Peat-swamp in Sulawesi, Indonesia

    OpenAIRE

    Zwahlen, Robert

    2017-01-01

    Rawa Aopa is a large swamp in South-East Sulawesi, Indonesia — the only major peat-swamp in this mainly mountainous island. Its vegetation and fauna are still quite poorly known. The existing information is summarized here. With the creation of new villages as part of Indonesia's transmigration programme, the human population in this area has increased very rapidly. Pressure on natural resources — especially soils and forests — is increasing, and primary forests are dwindling rapidly. This in...

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. Performance measures for a Mississippi River reintroduction into the forested wetlands of Maurepas Swamp

    Science.gov (United States)

    Krauss, Ken W.; Shaffer, Gary P.; Keim, Richard F.; Chambers, Jim L.; Wood, William B.; Hartley, Stephen B.

    2017-06-09

    The use of freshwater diversions (river reintroductions) from the Mississippi River as a restoration tool to rehabilitate Louisiana coastal wetlands has been promoted widely since the first such diversion at Caernarvon became operational in the early 1990s. To date, aside from the Bonnet Carré Spillway (which is designed and operated for flood control), there are only four operational Mississippi River freshwater diversions (two gated structures and two siphons) in coastal Louisiana, and they all target salinity intrusion, shellfish management, and (or) the enhancement of the integrity of marsh habitat. River reintroductions carry small sediment loads for various design reasons, but they can be effective in delivering fresh­water to combat saltwater intrusion and increase the delivery of nutrients and suspended fine-grained sediments to receiving wetlands. River reintroductions may be an ideal restoration tool for targeting coastal swamp forest habitat; much of the area of swamp forest habitat in coastal Louisiana is undergo­ing saltwater intrusion, high rates of submergence, and lack of riverine flow leading to reduced concentrations of important nutrients and suspended sediments, which sustain growth and regeneration, help to aerate swamp soils, and remove toxic compounds from the rhizosphere.The State of Louisiana Coastal Protection and Restora­tion Authority (CPRA) has made it a priority to establish a small freshwater river diversion into a coastal swamp forest located between Baton Rouge and New Orleans, Louisiana, to reintroduce Mississippi River water to Maurepas Swamp. While a full understanding of how a coastal swamp forest will respond to new freshwater loading through a Mississippi River reintroduction is unknown, this report provides guidance based on the available literature for establishing performance measures that can be used for evaluating the effectiveness of a Mississippi River reintroduction into the forested wetlands of Maurepas Swamp

  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. 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...

  7. 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.

  8. 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.

  9. Nonomuraea rhodomycinica sp. nov., isolated from peat swamp forest soil.

    Science.gov (United States)

    Sripreechasak, Paranee; Phongsopitanun, Wongsakorn; Supong, Khomsan; Pittayakhajonwut, Pattama; Kudo, Takuji; Ohkuma, Moriya; Tanasupawat, Somboon

    2017-06-01

    The taxonomic position of an actinomycete, strain NR4-ASC07T, isolated from a soil sample collected from Sirindhorn peat swamp forest, Narathiwat Province, Thailand, was clarified using a polyphasic approach. On the basis of morphological and chemotaxonomic characteristics, it was classified among the members of the genus Nonomuraea. It produced tightly closed spiral spore chains on aerial mycelium as well as forming a pseudosporangium. Whole-cell hydrolysates contained meso-diaminopimelic acid, glucose, ribose, madurose and mannose. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, lyso-phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides, unknown ninhydrin-positive phosphoglycolipids and unknown glycolipid. Menaquiones were MK-9(H4), MK-9(H0), MK-9(H2), MK-10(H4) and MK-9(H6). Predominant cellular fatty acids were iso-C16 : 0, C17 : 0 10-methyl, C16 : 0, C17 : 1ω8c, C16 : 0 2-OH and iso-C15 : 0. The phylogenetic tree reconstructed on the basis of 16S rRNA gene sequences showed that the strain fell within the clade containing Nonomuraea muscovyensis FMN03T, Nonomuraea roseoviolacea subsp. roseoviolaceaNBRC 14098T and Nonomuraea roseoviolacea subsp. carminataNBRC 15903T. The DNA-DNA relatedness and phenotypic data supported that strain NR4-ASC07T was clearly distinguished from the closely related species and represents a novel species of the genus Nonomuraea for which the name Nonomuraea rhodomycinica sp. nov. is proposed. The type strain is NR4-ASC07T (=NBRC 112327T=TISTR 2465T).

  10. Genetic characteristic of swamp buffalo (Bubalus bubalis) from Pampangan, South Sumatra based on blood protein profile

    Science.gov (United States)

    Windusari, Yuanita; Hanum, Laila; Wahyudi, Rizki

    2017-11-01

    Swamp buffalo (Bubalus bubalis) is an endemic species and one of the genetic wealth of South Sumatra with a distribution area in the district of Pampangan (OganIlir and OganOganIlir). Suspected inbreeding causes decreased phenotypic properties. Inbreeding among various swamp buffalo is certainly not only lower the qualities but also genotypes and phenotypes. It is of interest to determine kinship variants swamp buffaloes from Pampangan through the analysis of a blood protein profile. Blood protein profile of four variants swamps buffalo was studied by using five electrophoresis system i.e. pre-albumin (Palb), albumin (Alb), ceruloplasmin (Cp), transferrin (Tf) and transferrin post (Ptf). In this paper, it is obtained that there was no significant differences among the four variants of the buffaloes were used as a sample. Prealbumin has two alleles (Palb1 and Palb2), albumin has three alleles (Alba, AlbB, AlbC), ceruloplasmin has one allele (BPA), post-transferrin has one allele (PTFA) with an allele frequency 1.0000 at any time transferrin has two alleles (TFA and TFB) with the allele frequency of 0.7500 and 1.0000. Characteristics prealbumin (Palb), albumin (Alb), ceruloplasmin (Cp), and post-transferrin (P-tf) is monomorphic, while transferrin is polymorphic average heterozygosity values all loci (H) 0.1286. Based on average heterozygosity, the swamp buffalo (Bubalusbubalis) from Pampangan has low genetic variation and closest genetic relationship.

  11. 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

  12. 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.

  13. 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....

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. Using a dynamic hydrology model to predict mosquito abundances in flood and swamp water.

    Science.gov (United States)

    Shaman, Jeffrey; Stieglitz, Marc; Stark, Colin; Le Blancq, Sylvie; Cane, Mark

    2002-01-01

    We modeled surface wetness at high resolution, using a dynamic hydrology model, to predict flood and swamp water mosquito abundances. Historical meteorologic data, as well as topographic, soil, and vegetation data, were used to model surface wetness and identify potential fresh and swamp water breeding habitats in two northern New Jersey watersheds. Surface wetness was positively associated with the subsequent abundance of the dominant floodwater mosquito species, Aedes vexans, and the swamp water species, Anopheles walkeri. The subsequent abundance of Culex pipiens, a species that breeds in polluted, eutrophic waters, was negatively correlated with local modeled surface wetness. These associations permit real-time monitoring and forecasting of these floodwater and nonfloodwater species at high spatial and temporal resolution. These predictions will enable public health agencies to institute control measures before the mosquitoes emerge as adults, when their role as transmitters of disease comes into play.

  19. 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.

  20. 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.

  1. The Effects of Corrosive Chemicals on Corrosion Rate of Steel Reinforcement Bars: I. Swamp Water

    Directory of Open Access Journals (Sweden)

    Sulistyoweni Widanarko

    2010-10-01

    Full Text Available Most of infrastructures using steel concrete to reinforce the strength of concrete. Steel concrete is so vulnerable to chemical compounds that can cause corrosion. It can happen due to the presence of chemical compounds in acid environment in low pH level. These chemical compounds are SO42-, Cl-, NO3-. There are many swamp area in Indonesia. The acid contents and the concentration of ion sulphate, chlorides, and nitrate are higher in the swamp water than in the ground water .The objective of this research was to find out the influence of corrosive chemicals in the swamp water to the steel concrete corrosion rate. There were two treatment used: (1 emerging ST 37 and ST 60 within 60 days in the 'polluted' swamp water, (2 moving the ST 37 up and down periodically in the ' polluted' swamp water. Three variation of 'polluted' swamp water were made by increasing the concentration of corrosive chemical up to 1X, 5X and 10X respectively. The corrosion rate was measured by using an Immersion Method. The result of Immersion test showed that chloride had the greatest influence to corrosion rate of ST 37 and ST 60 and followed by sulphate and Nitrate. Corrosion rate value for ST 37 is 24.29 mpy and for ST 60 is 22.76 mpy. By moving the sample up and down, the corrosion rate of ST 37 increase up to 37.59 mpy, and chloride still having the greatest influence, followed by sulphate and nitrate.

  2. 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...

  3. 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...

  4. 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....

  5. 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...

  6. 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...

  7. Nutrition and feeding of swamp buffalo: feed resources and rumen approach

    Directory of Open Access Journals (Sweden)

    P. Rowlins

    2010-02-01

    Full Text Available Seasonal feed resources are of prime importance for swamp buffaloes to support the efficient production under the prevailing small-holder farming systems. Manipulations of rumen microorganisms, fermentation and subsequent absorption by the animals are essential. Current research work on locally available feed resources such as urea-treated rice straw, cassava hay etc. revealed significant improvement in rumen ecology with higher cellulolytic bacteria and fungal zoospores and subsequent fermentation endproducts. However, investigation of rumen microorganisms diversity of swamp buffalo and their roles in fermentation using molecular technique especially the use of PCR – DGGE/ Real Time- PCR warrant future research undertakings.

  8. Long-term disturbance dynamics and resilience of tropical peat swamp forests.

    Science.gov (United States)

    Cole, Lydia E S; Bhagwat, Shonil A; Willis, Katherine J

    2015-01-01

    1. The coastal peat swamp forests of Sarawak, Malaysian Borneo, are undergoing rapid conversion, predominantly into oil palm plantations. This wetland ecosystem is assumed to have experienced insignificant disturbance in the past, persisting under a single ecologically-stable regime. However, there is limited knowledge of the past disturbance regime, long-term functioning and fundamentally the resilience of this ecosystem to changing natural and anthropogenic perturbations through time. 2. In this study, long-term ecological data sets from three degraded peatlands in Sarawak were collected to shed light on peat swamp forest dynamics. Fossil pollen and charcoal were counted in each sedimentary sequence to reconstruct vegetation and investigate responses to past environmental disturbance, both natural and anthropogenic. 3. Results demonstrate that peat swamp forest taxa have dominated these vegetation profiles throughout the last c. 2000-year period despite the presence of various drivers of disturbance. Evidence for episodes of climatic variability, predominantly linked to ENSO events, and wildfires is present throughout. However, in the last c. 500 years, burning and indicators of human disturbance have elevated beyond past levels at these sites, concurrent with a reduction in peat swamp forest pollen. 4. Two key insights have been gained through this palaeoecological analysis: (i) peat swamp forest vegetation has demonstrated resilience to disturbance caused by burning and climatic variability in Sarawak in the late Holocene, however (ii) coincident with increased fire combined with human impact c. 500 years ago, these communities started to decline. 5.Synthesis. Sarawak's coastal peat swamps have demonstrated resilience to past natural disturbances, with forest vegetation persisting through episodes of fire and climatic variability. However, palaeoecological data presented here suggest that recent, anthropogenic disturbances are of a greater magnitude, causing

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.)

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

    Directory of Open Access Journals (Sweden)

    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.

  17. 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...

  18. 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,

  19. 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

  20. 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...

  1. 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...

  2. 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...

  3. 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 ...

  4. 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.

  5. 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.

  6. 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...

  7. 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....

  8. 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.

  9. 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...

  10. 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.

  11. Oil spill impact on the finfish of Azhiwari swamp, Joinkrama in the ...

    African Journals Online (AJOL)

    The impact of an oil spill on surface water, sediment and finfish assemblage characteristics in a freshwater swamp forest was assessed by dividing the wetland into four zones on the basis of spilled oil cover on the water surface – High Impact Zone (HIZ >60%), Medium Impact Zone (MIZ 30 – 60%), Low Impact Zone - (LIZ 5 ...

  12. Effect of gas flaring on plants in a tropical fresh water swamp forest ...

    African Journals Online (AJOL)

    An oil field in a fresh water swamp forest was visited during the wet and dry seasons to assess the impact of gas flaring on vegetation in the area. Gas flaring attracts yam beetles (Heteroligus spp.) and grasshopper (Zonocerus variegates) to the area, and these attack crops. Generally, the nearer plantain (Musa sp.) and oil ...

  13. Floristic composition and diversity of three swamp forests in northwest Guyana

    NARCIS (Netherlands)

    Andel, T.R. van

    2003-01-01

    This paper reviews the floristic composition, vegetation structure, and diversity of three types of swamp forest that cover a considerable part of Guyana’s North-West District. Trees, shrubs, lianas, herbs, and hemi-epiphytes were inventoried in three hectare plots: one in Mora forest, one in

  14. Management of Bottomland Hardwoods and Deepwater Swamps for Threatened and Endangered Species.

    Science.gov (United States)

    1999-12-01

    Zone Species II III IV V VI Acer negundo (boxelder) X X X X Acer rubrum (red maple) X X X X Alnus serrulata (common alder) X X X Amorpha...virginiana (persimmon) X X X X Euonymus americanus (strawberry bush) X X Fagus grandifolia (American beech) X X Forestiera acuminata (swamp privet) X

  15. Diversity and Antagonistic Activity of Actinomycete Strains From Myristica Swamp Soils Against Human Pathogens

    Directory of Open Access Journals (Sweden)

    Varghese Rlnoy

    2014-05-01

    Full Text Available Under the present investigation Actinomycetes were isolated from the soils of Myristica swamps of southern Western Ghats and the antagonistic activity against different human bacterial pathogens was evaluated. Results of the present study revealed that Actinomycetes population in the soils of Myristica swamp was spatially and seasonally varied. Actinomycetes load was varied from 24×104 to 71×103, from 129×103 to 40×103 and from 31×104 to 84×103 in post monsoon, monsoon and pre monsoon respectively. A total of 23 Actinomycetes strains belonging to six genera were isolated from swamp soils. Identification of the isolates showed that most of the isolates belonged to the genus Streptomyces (11, followed by Nocardia (6, Micromonospora (3, Pseudonocardia (1, Streptosporangium (1, and Nocardiopsis (1. Antagonistic studies revealed that 91.3% of Actinomycete isolates were active against one or more tested pathogens, of that 56.52% exhibited activity against Gram negative and 86.95% showed activity against Gram positive bacteria. 39.13% isolates were active against all the bacterial pathogens selected and its inhibition zone diameter was also high. 69.5% of Actinomycetes were exhibited antibacterial activity against Listeria followed by Bacillus cereus (65.21%, Staphylococcus (60.86%, Vibrio cholera (52.17%, Salmonella (52.17% and E. coli (39.13%. The results indicate that the Myristica swamp soils of Southern Western Ghats might be a remarkable reserve of Actinomycetes with potential antagonistic activity.

  16. Potential roles of fish, birds, and water in swamp privet (Forestiera acuminata) seed dispersal

    Science.gov (United States)

    Susan B. Adams; Paul B. Hamel; Kristina Connor; Bryce Burke; Emile S. Gardiner; David Wise

    2007-01-01

    Forestiera acuminata (swamp privet) is a common wetland shrub/small tree native to the southeastern United States. We examined several possible dispersal avenues for the plant. We tested germination of seeds exposed to various treatments, including passage through Ictalurus punctatus (Channel Catfi sh) guts, and conducted other...

  17. Skin disease affecting the conservation of the western swamp tortoise (Pseudemydura umbrina)

    Science.gov (United States)

    Ladyman, J M; Kuchling, G; Burford, D; Boardman, W; Raidal, S R

    1998-11-01

    To review the present position of the western swamp tortoise (Pseudemydura umbrina) as an endangered species and significant health issues affecting efforts to save it from extinction. A retrospective analysis of the husbandry, hospital and pathology records of the western swamp tortoise captive breeding program at Perth Zoo. In 1987 a captive breeding project was developed to prevent the extinction of the western swamp tortoise but an outbreak of a necrotising dermatitis in 1989 threatened the survival of the captive bred hatchlings. Less severe outbreaks occurred in 1990 and 1993, with isolated cases in between. Of 283 tortoises that were born in captivity or came into captivity from the wild, 37 (13.1%) were affected, comprising 37% of all males, 26% of all females and 13% of animals of unknown gender. Of the affected animals, 70% were less than 2 years of age and 29% were older. Males were 1.6 times more likely to be infected than females but this difference was not statistically significant (P = 0.27). Culture of the lesions consistently yielded unidentified Pseudomonas sp. Improved husbandry, such as strict maintenance of water quality and temperature conditions similar to that of the animal's natural habitat, and monitoring the health of individual tortoises have successfully controlled skin disease in the captive breeding of the western swamp tortoise.

  18. Decline of the Maurepas Swamp, Pontchartrain Basin, Louisiana, and Approaches to Restoration

    Directory of Open Access Journals (Sweden)

    Gary P. Shaffer

    2016-03-01

    Full Text Available The Maurepas swamp is the second largest contiguous coastal forest in Louisiana but it is highly degraded due to subsidence, near permanent flooding, nutrient starvation, nutria herbivory, and saltwater intrusion. Observed tree mortality rates at study sites in the Maurepas swamp are very high (up to 100% tree mortality in 11 years and basal area decreased with average salinities of <1 ppt. Habitat classification, vegetation productivity and mortality, and surface elevation changes show a clear trajectory from stagnant, nearly permanently flooded forests with broken canopy to degraded forests with sparse baldcypress and dominated by herbaceous species and open water to open water habitat for most of the Maurepas swamp without introduction of fresh water to combat saltwater intrusion and stimulate productivity and accretion. Healthy forests in the Maurepas are receiving fresh water containing nutrients and sediments from urban areas, high quality river water, or secondarily treated municipal effluent. Currently, two proposed diversions into the swamp are via Hope Canal (57 m3·s−1 and Blind River (142 m3·s−1. These diversions would greatly benefit their immediate area but they are too small to influence the entire Maurepas sub-basin, especially in terms of accretion. A large diversion (>1422 m3·s−1 is needed to deliver the adequate sediments to achieve high accretion rates and stimulate organic soil formation.

  19. Survey of economic trees in fresh water swamp of Calabar | Okon ...

    African Journals Online (AJOL)

    A survey of economic trees namely Elaeis guineensis (oil-palm) and Colocasia esculenta (taro) in fresh water swamp, Calabar was conducted. The survey area located in the vicinity of Cross River University of Technology (CRUTECH), Calabar premises covered an area of 0.5km x 0.2km was divided into five plots (A – E).

  20. Primary production in an impounded baldcypress swamp (Taxodium distichum) at the northern limit of the range

    Science.gov (United States)

    Middleton, B.A.; McKee, K.L.

    2005-01-01

    The ability of baldcypress (Taxodium distichum)swamps to maintain themselves near the northern limit of their range depends on their levels of production, which is not only are response to climate but also to local environmental factors(e.g., impoundment). We asked if primary production was reduced under impounded conditions and if species' responses to impoundment were individualistic or more generalized. To examine long-term production trends in a permanently impounded baldcypress swamp, a 6-year study of leaf litterfall was conducted in Buttonland Swamp, Illinois, which had been impounded for 10 years before the beginning of the study. Buttonland Swamp is at the northern boundary of the baldcypress swamp region along the Cache River, Illinois, in the Mississippi River Alluvial Valley of the United States. When the litter production of impounded sites was compared to those with natural hydrology in the same region, impounded sites had about half of the total litterfall of natural sites. Overall, leaf litterfall rates declined during the study(201 vs. 113 gm-2 yr-1), but the pattern was negatively correlated with water depth, which explained 97% of the variation in the data. Along the transect with the lowest mean minimum water depth(<0.5 cm), leaf litterfall decreased linearly over 6 years from 377 to 154gm-2 yr-1. Total leaf litterfall rates were lower at the other three depths(5, 43, and 49 cm mean minimum water depths)and remained below 200 gm-2 yr -1 throughout the study. Acer saccharinum, Nyssa aquatica, and Salix nigra were most responsible for the decline in total leaf litterfall. Amounts of leaf litterfall of T. distichum and Liquidambar styraciflua also generally decreased, while that of Cephalanthus occidentalis increased overtime. Because species' responses to environmental factors such as impoundment are individualistic, models should be based on the responses of individual species, rather than on communities. Our study further suggests that the

  1. 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...

  2. 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...

  3. Transforming Swamp Buffaloes to Producers of Milk and Meat Through Crossbreeding and Backcrossing

    Directory of Open Access Journals (Sweden)

    L C Cruz

    2009-09-01

    Full Text Available There are two major types of water buffaloes in the world, the riverine type and the swamp type. The total number of Swamp buffalo is 37.6 M and represents 21.8% of the world’s buffalo population. The swamp buffaloes have played a major role in draft animal-dependent farming system. But intensified rice production became more pronounced in irrigated areas and this has led to increased utilization of small farm machineries, displacing significantly the draft buffaloes for land tillage. To some extent, the introduction of tractors for land preparation and transport for corn, sugarcane and other crops in production areas has similar effect. Utilization of the existing population of swamp buffaloes to meet the growing domestic demand for milk and meat, against the background of increasing farm mechanization, is a good reason to transform the huge number of draft animals into producers of milk and meat. According to the UNDP/FAO-assisted project in the Philippines carried from 1982 to 1998, that crossing swamp buffalo and riverine buffaloes, despite the differences in chromosome numbers, is producing crossbreds with high growth rate potentials and milk production abilities several folds over the swamp buffalo parents. The known fact that swamp and riverine buffaloes have different chromosome number, the diploid chromosome number of the swamp buffalo is 48 and that of the river buffalo is 50. When crossbreeding between the 2 buffalo types occur, males and females of the F1 generation are heterozygous for the fusion and are apparently fertile with chromosome 2n = 49. Three-way crossbred hybrids were obtained by (native buffalo x Murrah x Nili Ravi or (native buffalo x Nili Ravi x Murrah. They had two chromosome categories viz. 2n=49 and 2n=50, respectively. Crossbreeding Swamp with Riverine Breed is done for quality beef. Most of the NT produced TenderBuff is farm-bred or purchased from other suppliers as swamp buffalo yearlings and growth out for a

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Logged peat swamp forest supports greater macrofungal biodiversity than large-scale oil palm plantations and smallholdings.

    Science.gov (United States)

    Shuhada, Siti Noor; Salim, Sabiha; Nobilly, Frisco; Zubaid, Akbar; Azhar, Badrul

    2017-09-01

    Intensive land expansion of commercial oil palm agricultural lands results in reducing the size of peat swamp forests, particularly in Southeast Asia. The effect of this land conversion on macrofungal biodiversity is, however, understudied. We quantified macrofungal biodiversity by identifying mushroom sporocarps throughout four different habitats; logged peat swamp forest, large-scale oil palm plantation, monoculture, and polyculture smallholdings. We recorded a total of 757 clusters of macrofungi belonging to 127 morphospecies and found that substrates for growing macrofungi were abundant in peat swamp forest; hence, morphospecies richness and macrofungal clusters were significantly greater in logged peat swamp forest than converted oil palm agriculture lands. Environmental factors that influence macrofungi in logged peat swamp forests such as air temperature, humidity, wind speed, soil pH, and soil moisture were different from those in oil palm plantations and smallholdings. We conclude that peat swamp forests are irreplaceable with respect to macrofungal biodiversity. They host much greater macrofungal biodiversity than any of the oil palm agricultural lands. It is imperative that further expansion of oil palm plantation into remaining peat swamp forests should be prohibited in palm oil producing countries. These results imply that macrofungal distribution reflects changes in microclimate between habitats and reduced macrofungal biodiversity may adversely affect decomposition in human-modified landscapes.

  9. Mapping swamp timothy (Cripsis schenoides) seed productivity using spectral values and vegetation indices in managed wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Rahilly, P.J.A.; Li, D.; Guo, Q.; Zhu, J.; Ortega, R.; Quinn, N.W.T.; Harmon, T.C.

    2010-01-15

    This work examines the potential to predict the seed productivity of a key wetland plant species using spectral reflectance values and spectral vegetation indices. Specifically, the seed productivity of swamp timothy (Cripsis schenoides) was investigated in two wetland ponds, managed for waterfowl habitat, in California's San Joaquin Valley. Spectral reflectance values were obtained and associated spectral vegetation indices (SVI) calculated from two sets of high resolution aerial images (May 11, 2006 and June 9, 2006) and were compared to the collected vegetation data. Vegetation data were collected and analyzed from 156 plots for total aboveground biomass, total aboveground swamp timothy biomass, and total swamp timothy seed biomass. The SVI investigated included the Simple Ratio (SR), Normalized Difference Vegetation Index (NDVI), Soil Adjusted Vegetation Index (SAVI), Transformed Soil Adjusted Vegetation Index (TSAVI), Modified Soil Adjusted Vegetation Index (MSAVI), and Global Environment Monitoring Index (GEMI). We evaluated the correlation of the various SVI with in situ vegetation measurements for linear, quadratic, exponential and power functions. In all cases, the June image provided better predictive capacity relative to May, a result that underscores the importance of timing imagery to coincide with more favorable vegetation maturity. The north pond with the June image using SR and the exponential function (R{sup 2}=0.603) proved to be the best predictor of swamp timothy seed productivity. The June image for the south pond was less predictive, with TSAVI and the exponential function providing the best correlation (R{sup 2}=0.448). This result was attributed to insufficient vegetal cover in the south pond (or a higher percentage of bare soil) due to poor drainage conditions which resulted in a delay in swamp timothy germination. The results of this work suggest that spectral reflectance can be used to estimate seed productivity in managed seasonal

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Great Dismal Swamp National Wildlife Refuge FY 1994 Prescribed Fire Proposal Plan Fringe Marsh-Highway 158

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan considers fire on Great Dismal Swamp National Wildlife Refuge as a tool for management and as a potential problem to be dealt with. This document discusses...

  15. Effects of historical and active nursery operations on the Great Swamp National Wildlife Refuge, Morris County, New Jersey

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report presents preliminary reconnaissance data on sediment and fish samples collected within the Great Swamp National Wildlife Refuge (GSNWR) Tract 141A - the...

  16. Dismal Swamp In Legend And History: George Washington Owned Large Tracts in Region Which He Described as a "Glorious Paradise"

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Ever since it was first explored, Dismal Swamp has remained a mystery place. Its last Indian disappeared around the 179o's, but in its depths it is almost as wild...

  17. A Compositional Study Of The Phytoplankton Of Lake Drummond And The Rivers And Canals That Drain The Dismal Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A six-week study of the phytoplankton in Lake Drummond and the canals and river which drain the Dismal Swamp resulted in the identification of 110 species. These...

  18. 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.

  19. 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...

  20. [Amphibians and reptiles in the swamps dominated by the palm Raphia taedigera (Arecaceae) in northeastern Costa Rica].

    Science.gov (United States)

    Bonilla-Murillo, Fabian; Beneyto, Davinia; Sasa, Mahmood

    2013-09-01

    The herpetofauna that inhabits Caribbean Costa Rica has received considerable attention in the last two decades. This assemblage includes a total of 141 species of reptiles and 95 amphibians mostly distributed in tropical wet and moist lowland forests. While most information available came from primary and secondary forest sites, little is known about the amphibians and reptiles that inhabit more open habitats, such as wetlands and swamps. For instances, swaps dominated by the yolillo palm Raphia taedigera extend through much of the northeastern Caribbean coast of Costa Rica and eastern Nicaragua, but information about the herpetological community that uses such environments remains practically unknown. This situation reflects the little research conducted in such inhospitable environments. Here, we report the results of an intensive survey conducted to assess the herpetological community that inhabit R. taedigera palm-swamps. A total of 14 species of amphibians and 17 of reptiles have been recorded from these swamps. Amphibians and reptiles that inhabit yolillo swamps have wide distributions along much of Middle America and are considered common species throughout their range. In general, yolillo swamps are poor environments for herpetofauna: richness of reptiles and amphibians is almost two times higher in the adjacent forest than in the palm dominated swamps. Furthermore, most species observed in this swamps can be considered habitat generalists that are well adapted to the extreme conditions imposed by the changes in hydroperiods, reduce understory cover, low tree diversity and simple forest architecture of these environments. Despite similarities in the herpetofauna, it is clear that not all forest species use yolillo habitat, a characteristic that is discussed in terms of physical stress driven by the prolonged hydroperiod and reduced leaflitter in the ground, as these features drive habitat structure and herpetofaunal complexity. Our list of species using

  1. AN OVERVIEW OF CESIUM-137 CONTAMINATION IN A SOUTHEASTERN SWAMP ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fledderman, P; Tim Jannik, T; Michael Paller, M

    2006-10-09

    In the early 1960s, an area of privately owned swamp adjacent to the Savannah River Site (SRS) was contaminated by site operations. Studies conducted in 1974 estimated that approximately 925 GBq of {sup 137}Cs and 37 GBq of {sup 60}Co were deposited in the swamp. Subsequently, a series of surveys was initiated to characterize the contaminated environment. These surveys--composed of 52 monitoring locations--allow for continued monitoring at a consistent set of locations. Initial survey results indicated maximum {sup 137}Cs concentrations of 19.5 Bq g{sup -1} in soil and 8.7 Bq g{sup -1} in vegetation. By the 2004-2005 surveys, maximum concentrations had declined to 1-2 Bq g{sup -1} in soil and 0.4 Bq g{sup -1} in vegetation.

  2. AN OVERVIEW OF CESIUM-137 CONTAMINATION IN A SOUTHEASTERN SWAMP ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fledderman, P; Tim Jannik, T; Michael Paller, M

    2007-04-04

    In the early 1960s, an area of privately owned swamp adjacent to the Savannah River Site (SRS) was contaminated by site operations. Studies conducted in 1974 estimated that approximately 925 GBq of {sup 137}Cs and 37 GBq of {sup 60}Co were deposited in the swamp. Subsequently, a series of surveys was initiated to characterize the contaminated environment. These surveys--composed of 52 monitoring locations--allow for continued monitoring at a consistent set of locations. Initial survey results indicated maximum {sup 137}Cs concentrations of 19.5 Bq g{sup -1} in soil and 8.7 Bq g{sup -1} in vegetation. By the 2004-2005 surveys, maximum concentrations had declined to 1-2 Bq g{sup -1} in soil and 0.4 Bq g{sup -1} in vegetation.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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...

  9. 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...

  10. 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.

  11. 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...

  12. 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...

  13. 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...

  14. Restoration and Management of a Degraded Baldcypress Swamp and Freshwater Marsh in Coastal Louisiana

    OpenAIRE

    Rachael G. Hunter; John W. Day; Gary P. Shaffer; Robert R. Lane; Andrew J. Englande; Robert Reimers; Demetra Kandalepas; William B. Wood; Jason N. Day; Eva Hillmann

    2016-01-01

    The Central Wetlands Unit (CWU), covering 12,000 hectares in St. Bernard and Orleans Parishes, Louisiana, was once a healthy baldcypress–water tupelo swamp and fresh and low salinity marsh before construction of levees isolated the region from Mississippi River floodwaters. Construction of the Mississippi River Gulf Outlet (MRGO), which funneled saltwater inland from the Gulf of Mexico, resulted in a drastic ecosystem change and caused mortality of almost all trees and low salinity marsh, but...

  15. Aquatic organisms as amber inclusions and examples from a modern swamp forest

    OpenAIRE

    Schmidt, Alexander R.; Dilcher, David L.

    2007-01-01

    To find aquatic organisms in tree resin may seem to be highly unlikely, but the fossil record provides numerous amber-preserved limnetic arthropods (e.g., water beetles, water striders, and crustaceans) and microorganisms (e.g., bacteria, algae, ciliates, testate amoebae, and rotifers). Here we explain the frequently discussed process of embedding aquatic organisms in tree resin based on field studies in a Florida swamp forest. Different aquatic arthropods and all major groups of limnetic mic...

  16. Latitudinal variation in carbon storage can help predict changes in swamps affected by global warming

    Science.gov (United States)

    Middleton, Beth A.; McKee, Karen

    2004-01-01

    Plants may offer our best hope of removing greenhouse gases (gases that contribute to global warming) emitted to the atmosphere from the burning of fossil fuels. At the same time, global warming could change environments so that natural plant communities will either need to shift into cooler climate zones, or become extirpated (Prasad and Iverson, 1999; Crumpacker and others, 2001; Davis and Shaw, 2001). It is impossible to know the future, but studies combining field observation of production and modeling can help us make predictions about what may happen to these wetland communities in the future. Widespread wetland types such as baldcypress (Taxodium distichum) swamps in the southeastern portion of the United States could be especially good at carbon sequestration (amount of CO2 stored by forests) from the atmosphere. They have high levels of production and sometimes store undecomposed dead plant material in wet conditions with low oxygen, thus keeping gases stored that would otherwise be released into the atmosphere (fig. 1). To study the ability of baldcypress swamps to store carbon, our project has taken two approaches. The first analysis looked at published data to develop an idea (hypothesis) of how production levels change across a temperature gradient in the baldcypress region (published data study). The second study tested this idea by comparing production levels across a latitudinal range by using swamps in similar field conditions (ongoing carbon storage study). These studies will help us make predictions about the future ability of baldcypress swamps to store carbon in soil and plant biomass, as well as the ability of these forests to shift northward with global warming.

  17. Nariva Swamp Ramsar Site, Trinidad and Tobago (West Indies) Wetland Habitat Restoration Initiative

    Science.gov (United States)

    Montserrat Carbonell; Nadra Nathai-Gyan

    2005-01-01

    Trinidad and Tobago, a twin island nation, is the most southerly of the Caribbean islands and lies just 11 km off the coast of Venezuela, near the Orinoco delta. Trinidad, the larger of the two islands, is approximately 5,000 km² and the Nariva Swamp is located on its eastern coast (fig. 1). In 1993, this site was designated as a wetland of international...

  18. 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.

  19. 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.

  20. 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 ...

  1. 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...

  2. 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...

  3. Repeated drought alters resistance of seed bank regeneration in baldcypress swamps of North America

    Science.gov (United States)

    Lei, Ting; Middleton, Beth A.

    2018-01-01

    Recurring drying and wetting events are likely to increase in frequency and intensity in predicted future droughts in the central USA and alter the regeneration potential of species. We explored the resistance of seed banks to successive droughts in 53 sites across the nine locations in baldcypress swamps in the southeastern USA. Along the Mississippi River Alluvial Valley and northern Gulf of Mexico, we investigated the capacity of seed banks to retain viable seeds after successive periods of drying and wetting in a greenhouse study. Mean differences in species richness and seed density were compared to examine the interactions of successive droughts, geographical location and water regime. The results showed that both species richness and total density of germinating seedlings decreased over repeated drought trials. These responses were more pronounced in geographical areas with higher annual mean temperature. In seed banks across the southeastern swamp region, most species were exhausted after Trial 2 or 3, except for semiaquatic species in Illinois and Tennessee, and aquatic species in Texas. Distinct geographical trends in seed bank resistance to drought demonstrate that climate-induced drying of baldcypress swamps could influence the regeneration of species differently across their ranges. Despite the health of adult individuals, lack of regeneration may push ecosystems into a relict status. Seed bank depletion by germination without replenishment may be a major conservation threat in a future with recurring droughts far less severe than megadrought. Nevertheless, the protection of moist refugia might aid conservation.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. The Evolution of a Freshwater Wetland in a Semi-arid Environment, Loboi Swamp, Kenya

    Science.gov (United States)

    Ashley, G. M.; Driese, S. G.; Mworia, J. M.; Muasya, A. M.; Hover, V. C.; Owen, R. B.; Goman, M. F.

    2002-12-01

    Loboi Swamp is situated near the equator on the western fault-bounded margin of an asymmetric half-graben within the East African Rift valley. The freshwater wetland is ~ 3km2 and developed during mid to late Holocene on the low relief floodplain of the axial Loboi River. The swamp is groundwater-fed by several springs and seeps associated with the border fault system. Spring waters are ~35°C, with pH ~6.4-6.9 and the water compositions suggest that the sources are shallow, and dominated by meteoric water with little contributed by deep re-circulating fluids. The climate is semi-arid. P is ~700 mm/yr on the valley bottom and 1200mm/yr in the adjacent highlands; ET is estimated to be ~2500 mm/yr. Variation in precipitation occurs on a range of time scales: semi-annual monsoonal rains in Nov. and April; El Nino and La Nina periods every 5-7 years; and long term variations in climate are also likely, such as, orbitally-forced Precession cycles (~20ka). The modern swamp is dominated by Typha domingensis Pers. (~80%) and Cyperus papyrus L. (20%), a crocodile habitat. The stratigraphy revealed in a soil pit and 8 piston cores (1.5-4 m long) records the formation, evolution and maybe the beginning of the demise of the wetland. Basal sediments are floodplain (sandy silts) that fine upward to f. silt and clay and are capped with organic-rich sediment (peat). Subparallel siderite concretion horizons in the silts indicate that Fe-reducing conditions developed as the basal sediments were flooded by the developing wetland. The peat is thickest (1.5 m) in the spring-proximal area near the fault and thins to 0.30m in the spring-distal areas. The appearance and expansion of peat indicates moister climate, however preliminary pollen analyses reveals that Cyperaceae and Tpyha are less abundant now than earlier suggesting a change from moister to drier conditions after the development of the swamp. Surface and porewater compositions in the swamp are modified by processes of

  12. 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

  13. 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.

  14. 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)

  15. Food swamps and food deserts in Baltimore City, MD, USA: associations with dietary behaviours among urban adolescent girls.

    Science.gov (United States)

    Hager, Erin R; Cockerham, Alexandra; O'Reilly, Nicole; Harrington, Donna; Harding, James; Hurley, Kristen M; Black, Maureen M

    2017-10-01

    To determine whether living in a food swamp (≥4 corner stores within 0·40 km (0·25 miles) of home) or a food desert (generally, no supermarket or access to healthy foods) is associated with consumption of snacks/desserts or fruits/vegetables, and if neighbourhood-level socio-economic status (SES) confounds relationships. Cross-sectional. Assessments included diet (Youth/Adolescent FFQ, skewed dietary variables normalized) and measured height/weight (BMI-for-age percentiles/Z-scores calculated). A geographic information system geocoded home addresses and mapped food deserts/food swamps. Associations examined using multiple linear regression (MLR) models adjusting for age and BMI-for-age Z-score. Baltimore City, MD, USA. Early adolescent girls (6th/7th grade, n 634; mean age 12·1 years; 90·7 % African American; 52·4 % overweight/obese), recruited from twenty-two urban, low-income schools. Girls' consumption of fruit, vegetables and snacks/desserts: 1·2, 1·7 and 3·4 servings/d, respectively. Girls' food environment: 10·4 % food desert only, 19·1 % food swamp only, 16·1 % both food desert/swamp and 54·4 % neither food desert/swamp. Average median neighbourhood-level household income: $US 35 298. In MLR models, girls living in both food deserts/swamps consumed additional servings of snacks/desserts v. girls living in neither (β=0·13, P=0·029; 3·8 v. 3·2 servings/d). Specifically, girls living in food swamps consumed more snacks/desserts than girls who did not (β=0·16, P=0·003; 3·7 v. 3·1 servings/d), with no confounding effect of neighbourhood-level SES. No associations were identified with food deserts or consumption of fruits/vegetables. Early adolescent girls living in food swamps consumed more snacks/desserts than girls not living in food swamps. Dietary interventions should consider the built environment/food access when addressing adolescent dietary behaviours.

  16. 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

  17. 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...

  18. Operational restoration of the Pen Branch bottomland hardwood and swamp wetlands - the research setting

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, E.A.

    2000-01-05

    The Savannah River Swamp is a 3020 Ha forested wetland on the floodplain of the Savannah River and is located on the Department of Energy's Savannah River Site (SRS) near Aiken, SC. Historically the swamp consisted of approximately 50 percent bald cypress-water tupelo stands, 40 percent mixed bottomland hardwood stands, and 10 percent shrub, marsh, and open water. Creek corridors were typical of Southeastern bottomland hardwood forests. The hydrology was controlled by flooding of the Savannah River and by flow from four creeks that drain into the swamp prior to flow into the Savannah River. Upstream dams have caused some alteration of the water levels and timing of flooding within the floodplain. Major impacts to the swamp hydrology occurred with the completion of the production reactors and one coal-fired powerhouse at the SRS in the early 1950's. Water was pumped from the Savannah River, through secondary heat exchangers of the reactors, and discharged into three of the tributary streams that flow into the swamp. Flow in one of the tributaries, Pen Branch, was typically 0.3 m3 s-1 (10-20) cfs prior to reactor pumping and 11.0 m3 s-1 (400 cfs) during pumping. This continued from 1954 to 1988 at various levels. The sustained increases in water volume resulted in overflow of the original stream banks and the creation of additional floodplains. Accompanying this was considerable erosion of the original stream corridor and deposition of a deep silt layer on the newly formed delta. Heated water was discharged directly into Pen Branch and water temperature in the stream often exceeded 65 degrees C. The nearly continuous flooding of the swamp, the thermal load of the water, and the heavy silting resulted in complete mortality of the original vegetation in large areas of the floodplain. In the years since pumping was reduced, early succession has begun in some affected areas. Most of this has been herbs, grasses, and shrubs. Areas that have seedlings are

  19. 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...

  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. 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...

  2. Research on Integrated Mapping——A Case Study of Integrated Land Use with Swamp Mapping

    Science.gov (United States)

    Zhang, S.; Yan, F.; Chang, L.

    2015-12-01

    Unified real estate registration system shows the attention, determination and effort to of CPC Central Committee and State Council on real estate registration in China. However, under current situation, China's real estate registration work made less progress. One of the reasons is that it's hard to express the property right of real estate on one map under the multi-sector management system. Under current multi-sector management system in China, different departments usually just survey and mapping the land type under its jurisdiction. For example, wetland investigation only mapping all kinds of wetland resources but not mapping other resource types. As a result, it cause he problem of coincidence or leak in integration of different results from different departments. As resources of the earth's surface, the total area of forest, grassland, wetland and so on should be equal to the total area of the earth's surface area. However, under the current system, the area of all kinds of resources is not equal to the sum of the earth's surface. Therefore, it is of great importance to express all the resources on one map. On one hand, this is conducive to find out the real area and distribution of resources and avoid the problem of coincidence or leak in integration; On the other hand, it is helpful to study the dynamic change of different resources. Therefore, we first proposed the "integrated mapping" as a solution, and take integrated land use with swamp mapping in Northeast China as an example to investigate the feasibility and difficulty. Study showed that: integrated land use with swamp mapping can be achieved through combining land use survey standards with swamps survey standards and "second mapping" program. Based on the experience of integrated land use with swamp mapping, we point out its reference function on integrated mapping and unified real estate registration system. We concluded that: (1) Comprehending and integrating different survey standard of

  3. De Novo Transcriptome Assembly of the Chinese Swamp Buffalo by RNA Sequencing and SSR Marker Discovery.

    Directory of Open Access Journals (Sweden)

    Tingxian Deng

    Full Text Available The Chinese swamp buffalo (Bubalis bubalis is vital to the lives of small farmers and has tremendous economic importance. However, a lack of genomic information has hampered research on augmenting marker assisted breeding programs in this species. Thus, a high-throughput transcriptomic sequencing of B. bubalis was conducted to generate transcriptomic sequence dataset for gene discovery and molecular marker development. Illumina paired-end sequencing generated a total of 54,109,173 raw reads. After trimming, de novo assembly was performed, which yielded 86,017 unigenes, with an average length of 972.41 bp, an N50 of 1,505 bp, and an average GC content of 49.92%. A total of 62,337 unigenes were successfully annotated. Among the annotated unigenes, 27,025 (43.35% and 23,232 (37.27% unigenes showed significant similarity to known proteins in NCBI non-redundant protein and Swiss-Prot databases (E-value < 1.0E-5, respectively. Of these annotated unigenes, 14,439 and 15,813 unigenes were assigned to the Gene Ontology (GO categories and EuKaryotic Ortholog Group (KOG cluster, respectively. In addition, a total of 14,167 unigenes were assigned to 331 Kyoto Encyclopedia of Genes and Genomes (KEGG pathways. Furthermore, 17,401 simple sequence repeats (SSRs were identified as potential molecular markers. One hundred and fifteen primer pairs were randomly selected for amplification to detect polymorphisms. The results revealed that 110 primer pairs (95.65% yielded PCR amplicons and 69 primer pairs (60.00% presented polymorphisms in 35 individual buffaloes. A phylogenetic analysis showed that the five swamp buffalo populations were clustered together, whereas two river buffalo breeds clustered separately. In the present study, the Illumina RNA-seq technology was utilized to perform transcriptome analysis and SSR marker discovery in the swamp buffalo without using a reference genome. Our findings will enrich the current SSR markers resources and help spearhead

  4. Effect of Combined Probiotics (Saccharomyces Cerevisae + Candida Utilis) and Herbs on Carcass Characteristics of Swamp Buffalo

    OpenAIRE

    Mahyuddin, P; Widiawati, Y

    2010-01-01

    A feedlot trial was conducted to study the effect of probiotics + herbs on carcass characteristics. Thirty male swamp buffaloes aged 2–2.5 years with the average body weight of 297 kg were used in this trial. They were fattened for 75 days to reach a slaughter weight of around 350–400 kg. They were divided into two groups of 15 animals in each group, and were placed in a shaded paddock. The groups were the control and the treated animals. The treated animals were given a supplementation conta...

  5. Historic simulation of net ecosystem carbon balance for the Great Dismal Swamp

    Science.gov (United States)

    Sleeter, Rachel

    2017-01-01

    Estimating ecosystem carbon (C) balance relative to natural disturbances and land management strengthens our understanding of the benefits and tradeoffs of carbon sequestration. We conducted a historic model simulation of net ecosystem C balance in the Great Dismal Swamp, VA. for the 30-year time period of 1985-2015. The historic simulation of annual carbon flux was calculated with the Land Use and Carbon Scenario Simulator (LUCAS) model. The LUCAS model utilizes a state-and-transition simulation model coupled with a carbon stock-flow accounting model to estimate net ecosystem C balance, and long term sequestration rates under various ecological conditions and management strategies. The historic model simulation uses age-structured forest growth curves for four forest species, C stock and flow rates for 8 pools and 14 fluxes, and known data for disturbance and management. The annualized results of C biomass are provided in this data release in the following categories: Growth, Heterotrophic Respiration (Rh), Net Ecosystem Production (NEP), Net Biome Production (NBP), Below-ground Biomass (BGB) Stock, Above-ground Biomass (AGB) Stock, AGB Carbon Loss from Fire, BGB Carbon Loss from Fire, Deadwood Carbon Loss from Management, and Total Carbon Loss. The table also includes the area (annually) of each forest type in hectares: Atlantic white cedar Area (hectares); Cypress-gum Area (hectares); Maple-gum Area (hectares); Pond pine Area (hectares). Net ecosystem production for the Great Dismal Swamp (~ 54,000 ha), from 1985 to 2015 was estimated to be a net sink of 0.97 Tg C. When the hurricane and six historic fire events were modeled, the Great Dismal Swamp became a net source of 0.89 Tg C. The cumulative above and belowground C loss estimated from the South One in 2008 and Lateral West fire in 2011 totaled 1.70 Tg C, while management activities removed an additional 0.01 Tg C. The C loss in below-ground biomass alone totaled 1.38 Tg C, with the balance (0.31 Tg C

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. 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...

  16. 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...

  17. 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...

  18. 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.

  19. 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

  20. 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

  1. Automatic categorization of land-water cover types of the Green Swamp, Florida, using Skylab multispectral scanner (S-192) data

    Science.gov (United States)

    Coker, A. E.; Higer, A. L.; Rogers, R. H.; Shah, N. J.; Reed, L. E.; Walker, S.

    1975-01-01

    The techniques used and the results achieved in the successful application of Skylab Multispectral Scanner (EREP S-192) high-density digital tape data for the automatic categorizing and mapping of land-water cover types in the Green Swamp of Florida were summarized. Data was provided from Skylab pass number 10 on 13 June 1973. Significant results achieved included the automatic mapping of a nine-category and a three-category land-water cover map of the Green Swamp. The land-water cover map was used to make interpretations of a hydrologic condition in the Green Swamp. This type of use marks a significant breakthrough in the processing and utilization of EREP S-192 data.

  2. Genetic Variation of mtDNA Cytochrome Oxidase Subunit I (COI in Local Swamp Buffaloes in Indonesia

    Directory of Open Access Journals (Sweden)

    F. Saputra

    2013-12-01

    Full Text Available The objective of this research was to identify genetic variation of mitochondria DNA especially in cytochrome oxidase subunit I (COI among population of Indonesian buffaloes. Samples of swamp buffaloes were collected from Aceh (n= 3, North Sumatra (n= 3, Riau (n= 3, Banten (n= 3, Central Java (n= 3, West Nusa Tenggara (n= 3 and South Sulawesi (n= 3, and riverine buffalo from North Sumatra (n= 1 out of group for comparison. Sequence of COI was analyzed using MEGA 5.10 software with neighbor-joining method kimura 2-parameter model to reconstruct phylogeny tree. The result showed that three haplotypes for swamp buffalo and one haplotype for riverine buffalo in Indonesia resulted from 41 polymorphic sites. This finding showed that the COI gene could be considered as a marker to distinguish among swamp buffaloes in Indonesia.

  3. 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.

  4. 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...

  5. Residu Gula Glikokonjugat pada Lambung Depan Kerbau Rawa (Bubalus bubalis Kalimantan Selatan (SUGAR RESIDU OF GLYCOCONJUGATES IN FORESTOMACH OF SOUTH KALIMANTAN SWAMP BUFFALO (BUBALUS BUBALIS

    Directory of Open Access Journals (Sweden)

    Anni Nurliani

    2014-08-01

    Full Text Available The ability of swamp buffaloes to adapt with swamp environment was suggested to be supported bytheir digestive system efficiency. The research was done to obtain scientific explanation about digestiveefficiency of swamp buffalo by identification on kinds and distribution of glycoconjugates in swamp buffaloforestomach. Six male swamp buffaloes aged more than 2.5 year old and had body weight between 300-400kg were used in this study. Samples were obtained from Regency of Banjar slaughter house, SouthKalimantan. Every parts of the forestomach included rumen, reticulum, and omasum was taken andprocessed for microscopic observation with hematoxyline eosin (HE and alcian blue-periodic acid schiff(AB-PAS stainings. Sugar residues of glycoconjugates were localized with lectin histochemistry wheatgerm agglutinin (WGA, ulex europaeus agglutinin (UEA, ricinus communis agglutinin (RCA, concanavalinagglutinin (Con A, and soybean agglutinin (SBA. Every part of swamp buffalo forestomach had kinds ofspecific glycoconjugates with special distribution pattern which were different with other ruminant, andwere suitable for their functions in that part. The existence of D mannose/D glucose glycoconjugates thatwas dominant in forestomach estimated that had important role in supporting fermentative digestionfunction in swamp buffalo, through its function as receptor bacteria attachment. This is suggested as aspecial characteristic in digestive system of swamp buffalo which causes high digestive efficiency inswamp buffalo.

  6. Peat swamp forest types and their regeneration in Giam Siak Kecil-Bukit Batu Biosphere Reserve, Riau, East Sumatra, Indonesia

    Directory of Open Access Journals (Sweden)

    H. Gunawan

    2012-04-01

    Full Text Available Although the ecology of tropical peat swamp forests is only now becoming understood, they are already under severe threat of conversion and degradation. Based on studies of the peat swamp forest of the Giam Siak Kecil–Bukit Batu Biosphere Reserve carried out between 2009 and 2010, this paper discusses forest types and regeneration processes in terms of promoting biodiversity conservation and sustainable management of the remaining peat swamp forest. Permanent plots covering a total area of three hectares were established in natural and disturbed forest areas. Within these plots, 135 tree species belonging to 34 families were identified. Mixed peat swamp forest and bintangur forest, which have different dominant species, were identified as the main forest types. The greatest species richness was in logged-over forest, with 82 species and a density of 2,492 stems ha-1. The success of regeneration varied between typical main species in the logged-over forest and in forest disturbed by wind and fire. All of the forest stands had high densities of trees with diameters at breast height (DBH of 3–10 cm, which are a potential source of recruitment to ensure the sustained regeneration of the forest remaining in the Biosphere Reserve. Regeneration is very important for improving the condition of disturbed peat swamp forest areas in the reserve, but natural regeneration will not be sufficient to restore the forest vegetation and conserve the associated biodiversity. Some form of human-assisted accelerated regeneration will be needed, such as enrichment planting of typical canopy species that have problems with establishment. It is important for the remaining natural peat swamp forests to be conserved because of their unique forest-type formations which have distinct dominant species, floristic composition, diversity and local environment characteristics. Improved management of secondary forest must be achieved through rehabilitation, halted forest

  7. Aquatic organisms as amber inclusions and examples from a modern swamp forest

    Science.gov (United States)

    Schmidt, Alexander R.; Dilcher, David L.

    2007-01-01

    To find aquatic organisms in tree resin may seem to be highly unlikely, but the fossil record provides numerous amber-preserved limnetic arthropods (e.g., water beetles, water striders, and crustaceans) and microorganisms (e.g., bacteria, algae, ciliates, testate amoebae, and rotifers). Here we explain the frequently discussed process of embedding aquatic organisms in tree resin based on field studies in a Florida swamp forest. Different aquatic arthropods and all major groups of limnetic microorganisms were found embedded in resin that had contact with swamp water. The taphonomy of aquatic organisms differs from that of terrestrial plants and animals that get stuck on resin surfaces and are enclosed by successive resin outflows. Large and highly motile arthropods are predestined for embedding. The number of microbial inclusions is increased when tiny drops of water with aquatic organisms become enclosed in resin while it is flowing in an aquatic environment. Bacteria and fungi may grow inside the resin as long as it has not solidified and therefore become secondarily accumulated. In contact with air, even resin that had initially been flowing into water may solidify and potentially form amber. PMID:17940051

  8. Pharmacokinetics of amoxicillin trihydrate in Thai swamp buffaloes (Bubalus bubalis): a pilot study.

    Science.gov (United States)

    Ruennarong, N; Wongpanit, K; Sakulthaew, C; Giorgi, M; Klangkaew, N; Poapolathep, A; Poapolathep, S

    2017-04-01

    This study aimed to investigate the pharmacokinetic characteristics of amoxicillin (AMX) in Thai swamp buffaloes, Bubalus bubalis, following single intramuscular administration at two dosages of 10 and 20 mg/kg body weight (b.w.). Blood samples were collected at assigned times up to 48 h. The plasma concentrations of AMX were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The concentrations of AMX in the plasma were determined up to 24 h after i.m. administration at both dosages. The Cmax values of AMX were 3.39 ± 0.18 μg/mL and 6.16 ± 0.18 μg/mL at doses of 10 and 20 mg/kg, respectively. The AUClast values increased in a dose-dependent fashion. The half-life values were 5.56 ± 0.40 h and 4.37 ± 0.23 h at doses of 10 and 20 mg/kg b.w, respectively. Based on the pharmacokinetic data and PK-PD index (T > MIC), i.m. administration of AMX at a dose of 20 mg/kg b.w might be appropriate for the treatment of susceptible Mannheimia haemolytica infection in Thai swamp buffaloes. © 2016 John Wiley & Sons Ltd.

  9. Food swamps by area socioeconomic deprivation in New Zealand: a national study.

    Science.gov (United States)

    Sushil, Zaynel; Vandevijvere, Stefanie; Exeter, Daniel J; Swinburn, Boyd

    2017-11-01

    A nationwide spatial analysis of community retail food environments in relation to area socioeconomic deprivation was conducted in New Zealand. Addresses from about 20,000 registered food outlets were retrieved from all 66 Councils. Outlets were classified, geocoded and (spatially) validated. The analysis included 4087 convenience, 4316 fast food/takeaway and 1271 supermarket and fruit/vegetable outlets and excluded outlets not considered 'healthy' or 'unhealthy'. The population-weighted density of different outlet types in Census areas and the proximity to different outlet types from Meshblock centres were calculated and associations with area socioeconomic deprivation assessed. Spatial scan statistics was used to identify food swamp areas with a significantly higher relative density of unhealthy outlets than other areas. A significantly positive association was observed between area deprivation and density of all retailers. A significantly negative association was observed between area deprivation and proximity to all retailers. Nationwide, 722 Census areas were identified as food swamps. Access to food retailers is significantly higher in more deprived areas than in less deprived areas. Restricting unhealthy outlets in areas with a high relative density of those outlets is recommended.

  10. STRUCTURE OF NATURAL REGENERATION IN RELATION TO SOIL PROPERTIES AND DISTURBANCE IN TWO SWAMP FORESTS

    Directory of Open Access Journals (Sweden)

    Marly Antonielle Ávila

    2016-03-01

    Full Text Available Veredas (palm swamps is a type of vegetation associated with watercourses, characterized by the presence of Mauritia flexuosa palm trees. These systems are not well understood and suffer from high anthropogenic pressure. The aims of this study were to describe the natural regeneration of two swamp forests in vereda systems with different anthropogenic impacts and investigate if the variation in these plant communities are associated to edaphic conditions. The study was performed in preserved and impacted sites located in the Environmental Protection Area of the Pandeiros River in northern Minas Gerais. At each site, one hundred 25 m2 plots were established for surveying regenerating shrubs and trees (≥1 cm diameter at the base of the stem and < 3 cm diameter at breast height. Vegetation structure was evaluated by phytosociological parameters, similarity index, and size distribution of individuals. Regenerating strata was correlated with chemical and physical soil analyses. The vegetation at the preserved site was characterized by a higher number of individuals and a lower diversity but contained species that were typical of flooded areas. The results also showed differences in soil nutrient availability between sites that influenced the distribution of species at the two study sites.

  11. Effects of Lasia spinosa Thw. on growth rate and reproductive hormone of weaned Swamp buffalo and Murrah X Swamp buffalo calves

    Directory of Open Access Journals (Sweden)

    M. Kamonpatana

    2010-02-01

    Full Text Available The effects of Lasia spinosa Thw. on growth rate and plasma Oestradiol 17- β (E2, Progesterone (P4 and Testosterone (T were studied in 16 male and female swamp (SS buffaloes and Murrah x Swamp buffalo crossbreeds (MS calves. The treatment group was fed with a concentrate supplemented with 30 g of dry powder of L. spinosa/head/d for 7 months. It was found that L .spinosa could have effect on male and female buffalo growth rate. The growth rate of male SS treated group were 130 g/d higher than control group. In female both SS and MS buffalo, the highest growth rate (830 to 840 g/d was found after the 2nd month of treatment while a reduction in growth rate (-1,030 to - 450 g/d was found in the 3rd month. After that the growth rate of SS and MS gradually increased until the last three months to 200 and 80 g/d in average, respectively. In female MS, plasma E2 in the treated group was lower than control group during Jan to Jul. Similar result was found in SS female, level of plasma E2 in treated group was lower than in control group in the first and last three month and there was no difference of plasma E2 in May. In MS male, the level of plasma E2 of treated group was higher than control group in Jan, Mar, Apr and Jul. In SS male, the level of plasma E2 of treated group was higher than control group in every month except in Jul. In female SS, L. spinosa could decreased plasma P4 through the experiment and could not have an effect on plasma P4 in female MS and plasma T in male buffalo calves. In conclusion, the addition to the concentrate of dry powder of L. spinosa 30 g/headl/d had an effect to increase growth rate in male SS and female MS buffalo calves, decrease plasma E2 in female both SS and MS and male SS and decrease plasma P4 in female SS.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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...

  20. 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)

  1. 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.

  2. 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

  3. 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...

  4. 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...

  5. 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

  6. 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.

  7. 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.

  8. 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...

  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. 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.

  11. First record of epizootic ulcerative syndrome from the Upper Congo catchment: An outbreak in the Bangweulu swamps, Zambia.

    Science.gov (United States)

    Huchzermeyer, C F; Huchzermeyer, K D A; Christison, K W; Macey, B M; Colly, P A; Hang'ombe, B M; Songe, M M

    2018-01-01

    We report on the first outbreak of epizootic ulcerative syndrome (EUS) amongst wild fish populations in the Bangweulu swamps, an inland delta, in the north of Zambia during 2014. The area supports a large and diverse fish fauna related to, but distinct from, that of the Zambezi River system where EUS outbreaks have occurred since 2006. A sizeable artisanal fishery, based on extensive fish weirs, is sustained by the annual flooding of the swamps, and observations of the disease outbreak by fishermen were recorded. Signs typical of infection with Aphanomyces invadans were observed in a number of species. Clinical observations, histology and molecular diagnostic methods were used to confirm infection with A. invadans in two of the most commonly and severely affected species. Several features of the wetland may have contributed to the outbreak and the annual recurrence of the disease. Modes by which the disease may have been introduced into the swamps are discussed. The outbreak is of great significance as the Bangweulu swamps drain into the Congo River in neighbouring Democratic Republic of Congo, Africa's largest drainage system with an extensive and diverse fish fauna previously unaffected by EUS. © 2017 John Wiley & Sons Ltd.

  12. On a new species of blackwater prawn, Macrobrachium oxyphilus (Crustacea: Decapoda: Caridea: Palaemonidae), from peat swamps in Peninsular Malaysia

    NARCIS (Netherlands)

    Ng, P.K.L.

    1992-01-01

    A new species of freshwater palaemonid prawn, Macrobrachium oxyphilus spec, nov., is described from highly acidic blackwaters in a peat swamp forest in Selangor, Peninsular Malaysia. The species differs from its nearest congener, M. trompii (de Man, 1898), in having proportionately smaller eyes,

  13. Variation in flood tolerance of container-grown seedlings of swamp white oak, bur oak, and white oak

    Science.gov (United States)

    Michael P. Walsh; J.W. Van Sambeek; Mark V. Coggeshall

    2008-01-01

    How much variation in flood tolerance exists among seedlings within oak species, given the flood frequency of sites from which acorns are collected, has been largely unexplored. Our studies examined initial growth and flood tolerance for seedlings of swamp white oak (Quercus bicolor Willd.), bur oak (Q. macrocarpa L.), and white...

  14. Ecological studies on a population of the water snake Grayia smythii in a rainforest swamp of the Niger Delta, Nigeria

    NARCIS (Netherlands)

    Akani, Godfrey C.; Luiselli, Luca

    2001-01-01

    The ecology of the water snake, Grayia smythii (Reptilia: Colubridae) occurring in a seasonal rainforest swamp of the Niger Delta (southern Nigeria) was investigated between December 1998 and March 2000. Females and males were similar in body sizes (SVL) and head sizes, but males had tails

  15. Satellite radar observation of tropical peat swamp forest as a tool for hydrological modelling and environmental protection

    NARCIS (Netherlands)

    Hoekman, D.H.

    2007-01-01

    1. Tropical peat swamp forests may contain as much as 20% of the global soil carbon stock. They are threatened by large-scale deforestation and canal drainage. Oxidation and forest fire cause enormous carbon emissions. Most remaining areas are located in Indonesia. These are becoming increasingly

  16. Soil warming alters seed-bank responses across the geographic range of freshwater Taxodium distichum (Cupressaceae) swamps

    Science.gov (United States)

    Middleton, Beth A.; McKee, Karen L.

    2011-01-01

    Premise of the Study: Climate warming is predicted to have far-reaching effects on the distribution of species, but those effects may depend on the flexibility of regenerating species in responding to climate gradients. We conducted a study to determine whether the variation in the response of seed banks to temperature varied across the latitudinal range of Taxodium distichum swamps in North America.

  17. [Distribution, surface and protected area of palm-swamps in Costa Rica and Nicaragua].

    Science.gov (United States)

    Serrano-Sandí, Juan; Bonilla-Murillo, Fabian; Sasa, Mahmood

    2013-09-01

    In Central America, palm swamps are known collectively as yolillales. These wetlands are usually dominated by the raffia palm Raphia taedigera, but also by the royal palm Manicaria saccifera and -in lower extensions- by the American oil palm Elaeis oleifera. The yolillales tend to be poor in woody species and are characteristic of regions with high rainfall and extensive hydroperiods, so they remain flooded most of the year. The dominance of large raffia palm leaves in the canopy, allow these environments to be distinguishable in aerial photographs, which consequently has helped to map them along most of their distribution. However, while maps depicting yolillales are available, the extent of their surface area, perimeter and connectivity remains poorly understood. This is particularly true for yolillales in Costa Rica and Nicaragua, countries that share a good proportion of palm dominated swaps in the Rio San Juan Basin. In addition, it is not known the actual area of these environments that is under any category of protection according to the conservation systems of both countries. As a first step to catalog yolillal wetlands in Costa Rica and Nicaragua, this paper evaluates cartographic maps to delineate yolillales in the region. A subsample of yolillales mapped in this study were visited and we geo-referenced them and evaluate the extent and condition of the swamp. A total of 110 883.2ha are classified as yolillales in Nicaragua, equivalent to 22% of wetland surface area recorded for that country (excluding the Cocibolca and Xolothn Lakes). In Costa Rica, 53 931.3ha are covered by these palm dominated swamps, which represent 16.24% of the total surface area covered by wetlands. About 47% of the area covered by yolillales in Nicaragua is under some category of protection, the largest extensions protected by Cerro Silva, Laguna Tale Sulumas and Indio Maiz Nature Reserves. In Costa Rica, 55.5% of the area covered by yolillal is located within protected areas

  18. 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.

  19. 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

  20. 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.

  1. Use of a 15N tracer to determine linkages between a mangrove and an upland freshwater swamp

    Science.gov (United States)

    MacKenzie, R. A.; Cormier, N.

    2005-05-01

    Mangrove forests and adjacent upland freshwater swamps are important components of subsistence-based economies of Pacific islands. Mangroves provide valuable firewood (Rhizophora apiculata) and mangrove crabs (Scylla serrata); intact freshwater swamps are often used for agroforestry (e.g., taro cultivation). While these two systems are connected hydrologically via groundwater and surface flows, little information is available on how they may be biogeochemically or ecologically linked. For example, mangrove leaf litter was once thought to be an important food source for resident and transient nekton and invertebrates, but this value may have been overestimated. Instead, nutrients or allochthonous material (e.g., phytoplankton, detritus) delivered via groundwater or surface water from upland freshwater swamps may play a larger role in mangrove food webs. Understanding the linkages between these two ecologically and culturally important ecosystems will help us to understand the potential impacts of hydrological alterations that occur when roads or bridges are constructed through them. We conducted a 15N tracer study in the Yela watershed on the island of Kosrae, Federated States of Micronesia. K15NO3 was continually added at trace levels for 4 weeks to the Yela River in an upland freshwater swamp adjacent to a mangrove forest. Nitrate and ammonium pools, major primary producers, macroinvertebrates, and fish were sampled from stations 5 m upstream (freshwater swamp) and 138, 188, 213, and 313 m downstream (mangrove) from the tracer addition. Samples were collected once a week prior to, during, and after the 15N addition for a total of 6 weeks. Preliminary results revealed no significant enrichment (mudskipper fish (Periophthalmus sp.). However, the 15N signature of ammonium pools was enriched 10-60 ‰ by the end of the third week. These results suggest that the tracer was present in the mangrove but was either unavailable to higher organisms or was incorporated into

  2. 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

  3. Effect of supplementary lighting on eating behaviour by corralled swamp buffalo (Bubalus bubalis heifers in Thailand

    Directory of Open Access Journals (Sweden)

    Chanvit Vajrabukka

    2007-03-01

    Full Text Available Sixteen 14-month-old swamp buffalo (Bubalus bubalis heifers were used to study the effect of supplementary lighting on eating time, number of meals and meal duration and growth performance. Eightheifers were allocated to a natural photoperiod regime, receiving approximately 12 h of daylight, (control treatment and eight heifers were allocated to a supplementary lighting regime, receiving an additional 6 h of artificial light during the night, (light supplemented treatment using a cross-over design. Rice straw wasoffered ad libitum and commercial concentrate was also offered approximately 1.5 kg/animal/day. Supplementary lighting was provided by eight 60 W white fluorescent tubes placed approximately 2.5 m above theground under the roof. Supplementary lighting did not significantly effect eating behaviour, daily intake or live weight gain. It is concluded that the performance of corralled buffalo heifers cannot be improved by the provision of supplementary lighting.

  4. Clonal growth strategy, diversity and structure: A spatiotemporal response to sedimentation in tropical Cyperus papyrus swamps.

    Science.gov (United States)

    Geremew, Addisie; Stiers, Iris; Sierens, Tim; Kefalew, Alemayehu; Triest, Ludwig

    2018-01-01

    Land degradation and soil erosion in the upper catchments of tropical lakes fringed by papyrus vegetation can result in a sediment load gradient from land to lakeward. Understanding the dynamics of clonal modules (ramets and genets) and growth strategies of plants on such a gradient in both space and time is critical for exploring a species adaptation and processes regulating population structure and differentiation. We assessed the spatial and temporal dynamics in clonal growth, diversity, and structure of an emergent macrophyte, Cyperus papyrus (papyrus), in response to two contrasting sedimentation regimes by combining morphological traits and genotype data using 20 microsatellite markers. A total of 636 ramets from six permanent plots (18 x 30 m) in three Ethiopian papyrus swamps, each with discrete sedimentation regimes (high vs. low) were sampled for two years. We found that ramets under the high sedimentation regime (HSR) were significantly clumped and denser than the sparse and spreading ramets under the low sedimentation regime (LSR). The HSR resulted in significantly different ramets with short culm height and girth diameter as compared to the LSR. These results indicated that C. papyrus ameliorates the effect of sedimentation by shifting clonal growth strategy from guerrilla (in LSR) to phalanx (in HSR). Clonal richness, size, dominance, and clonal subrange differed significantly between sediment regimes and studied time periods. Each swamp under HSR revealed a significantly high clonal richness (R = 0.80) as compared to the LSR (R = 0.48). Such discrepancy in clonal richness reflected the occurrence of initial and repeated seedling recruitment strategies as a response to different sedimentation regimes. Overall, our spatial and short-term temporal observations highlighted that HSR enhances clonal richness and decreases clonal subrange owing to repeated seedling recruitment and genets turnover.

  5. Population density of red langurs in Sabangau tropical peat-swamp forest, Central Kalimantan, Indonesia.

    Science.gov (United States)

    Ehlers Smith, David A; Ehlers Smith, Yvette C

    2013-08-01

    Because of the large-scale destruction of Borneo's rainforests on mineral soils, tropical peat-swamp forests (TPSFs) are increasingly essential for conserving remnant biodiversity, particularly in the lowlands where the majority of habitat conversion has occurred. Consequently, effective strategies for biodiversity conservation are required, which rely on accurate population density and distribution estimates as a baseline. We sought to establish the first population density estimates of the endemic red langur (Presbytis rubicunda) in Sabangau TPSF, the largest remaining contiguous lowland forest-block on Borneo. Using Distance sampling principles, we conducted line transect surveys in two of Sabangau's three principle habitat sub-classes and calculated group density at 2.52 groups km⁻² (95% CI 1.56-4.08) in the mixed-swamp forest sub-class. Based on an average recorded group size of 6.95 individuals, population density was 17.51 ind km⁻², the second highest density recorded in this species. The accessible area of the tall-interior forest, however, was too disturbed to yield density estimates representative of the entire sub-class, and P. rubicunda was absent from the low-pole forest, likely as a result of the low availability of the species' preferred foods. This absence in 30% of Sabangau's total area indicates the importance of in situ population surveys at the habitat-specific level for accurately informing conservation strategies. We highlight the conservation value of TPSFs for P. rubicunda given the high population density and large areas remaining, and recommend 1) quantifying the response of P. rubicunda to the logging and burning of its habitats; 2) surveying degraded TPSFs for viable populations, and 3) effectively delineating TPSF sub-class boundaries from remote imagery to facilitate population estimates across the wider peat landscape, given the stark contrast in densities found across the habitat sub-classes of Sabangau. © 2013 Wiley

  6. Effect of day or night grazing on behaviour of swamp buffalo heifers

    Directory of Open Access Journals (Sweden)

    Somparn, P.

    2007-03-01

    Full Text Available An experiment was conducted to examine the effect of day or night grazing on behaviour by swamp buffaloes. A grazing trial was conducted over 42 days in the late rainy season, during September to November2005 at Surin Livestock Research and Breeding Center, Surin province. The experimental period was divided into two 21-day periods. Twelve 2-year-old swamp buffalo heifers were allocated to four groups, eachcontaining three heifers, with the mean group weights being as similar as possible. Each group was allowed to graze either from 06:20 to 18:00 h (daytime treatment or from 18:20 to 06:00 h (nighttime treatment infour separate paddocks, each of 5 rai, using a cross-over design. When not at pasture the animals in each group were kept in the common corral with free access to fresh drinking water and mineral blocks. Individualanimal activity was recorded by visual observation at 1-min intervals during the period at pasture. Individual groups within each period were treated as replicates. Differences between group means weretested using MIXED procedure of SAS.The buffaloes on daytime treatment spent longer (P<0.05 grazing than those on nighttime treatment (423 vs 332 min. The number of meals differed (P<0.05 between treatments, but overall mean meal durationswere similar (73 min. Buffaloes allowed to graze during daylight had a tendency (P<0.10 toward a higher bite and step rates than those grazing during the night. With the reduction in grazing activity duringthe night on nighttime treatment, the animals ruminated for longer during the period at pasture (327 and 191 min, P<0.001. Live-weight change over periods of 20 days did not differ significantly. The difference intemporal behaviour patterns between treatments indicated that animals have to adapt foraging strategies appropriate for different situations in order to maintain feed intake and subsequently production.

  7. Clonal growth strategy, diversity and structure: A spatiotemporal response to sedimentation in tropical Cyperus papyrus swamps.

    Directory of Open Access Journals (Sweden)

    Addisie Geremew

    Full Text Available Land degradation and soil erosion in the upper catchments of tropical lakes fringed by papyrus vegetation can result in a sediment load gradient from land to lakeward. Understanding the dynamics of clonal modules (ramets and genets and growth strategies of plants on such a gradient in both space and time is critical for exploring a species adaptation and processes regulating population structure and differentiation. We assessed the spatial and temporal dynamics in clonal growth, diversity, and structure of an emergent macrophyte, Cyperus papyrus (papyrus, in response to two contrasting sedimentation regimes by combining morphological traits and genotype data using 20 microsatellite markers. A total of 636 ramets from six permanent plots (18 x 30 m in three Ethiopian papyrus swamps, each with discrete sedimentation regimes (high vs. low were sampled for two years. We found that ramets under the high sedimentation regime (HSR were significantly clumped and denser than the sparse and spreading ramets under the low sedimentation regime (LSR. The HSR resulted in significantly different ramets with short culm height and girth diameter as compared to the LSR. These results indicated that C. papyrus ameliorates the effect of sedimentation by shifting clonal growth strategy from guerrilla (in LSR to phalanx (in HSR. Clonal richness, size, dominance, and clonal subrange differed significantly between sediment regimes and studied time periods. Each swamp under HSR revealed a significantly high clonal richness (R = 0.80 as compared to the LSR (R = 0.48. Such discrepancy in clonal richness reflected the occurrence of initial and repeated seedling recruitment strategies as a response to different sedimentation regimes. Overall, our spatial and short-term temporal observations highlighted that HSR enhances clonal richness and decreases clonal subrange owing to repeated seedling recruitment and genets turnover.

  8. Hydrologic remediation for the Deepwater Horizon incident drove ancillary primary production increase in coastal swamps

    Science.gov (United States)

    Middleton, Beth A.; Johnson, Darren; Roberts, Brian J

    2015-01-01

    As coastal wetlands subside worldwide, there is an urgency to understand the hydrologic drivers and dynamics of plant production and peat accretion. One incidental test of the effects of high rates of discharge on forested wetland production occurred in response to the 2010 Deepwater Horizon incident, in which all diversions in Louisiana were operated at or near their maximum discharge level for an extended period to keep offshore oil from threatened coastal wetlands. Davis Pond Diversion was operated at six times the normal discharge levels for almost 4 months, so that Taxodium distichum swamps downstream of the diversion experienced greater inundation and lower salinity. After this remediation event in 2010, above-ground litter production increased by 2.7 times of production levels in 2007–2011. Biomass of the leaf and reproductive tissues of several species increased; wood litter was minimal and did not change during this period. Root production decreased in 2010 but subsequently returned to pre-remediation values in 2011. Both litter and root production remained high in the second growing season after hydrologic remediation. Annual tree growth (circumference increment) was not significantly altered by the remediation. The potential of freshwater pulses for regulating tidal swamp production is further supported by observations of higher T. distichum growth in lower salinity and/or pulsed environments across the U.S. Gulf Coast. Usage of freshwater pulses to manage altered estuaries deserves further consideration, particularly because the timing and duration of such pulses could influence both primary production and peat accretion.

  9. Damage suffered by swamp morning glory (Ipomoea aquatica Forsk) exposed to vanadium (V).

    Science.gov (United States)

    Chen, Ting; Li, Ting-Qiang; Yang, Jin-Yan

    2016-03-01

    To elucidate the physiological and morphological responses generated by vanadium (V) in plants, hydroponic culture experiments were performed with swamp morning glory (Ipomoea aquatica Forsk) exposed to 0 mg L(-1) to 2.50 mg L(-1) pentavalent V [V(V)] in Hoagland nutrient solutions. The concentration of chlorophyll a, chlorophyll b, and carotene peaked at a V(V) concentration of 0.05 mg L(-1) and gradually decreased at higher V(V) concentrations. Similarly, the plant biomass was stimulated at low levels of V(V) and was inhibited when V(V) concentrations exceeded 0.1 mg L(-1). Pentavalent V had negative effects on the uptake of phosphorus (P) by roots, shoots, and leaves. The biological absorption coefficients of V of the roots were higher than those of the aerial parts. Under low concentrations of V(V) exposure, the predominant species of V in the aerial parts was tetravalent V [V(IV)], whereas V(V) became more prevalent when concentrations of V(V) in the solution was higher than 0.50 mg L(-1). In the roots, however, the concentrations of V(V) were always higher than those of the V(IV), except in the control group. Organelles in the V(V)-treated leaves were distorted, and the periplasmic space became wider. These results indicate V(V) has concentration-dependent effects on the physiological properties of swamp morning glory, whereas the plant has the ability to develop self-protective function to adapt to the toxicity of V(V). © 2015 SETAC.

  10. The inorganic chemistry of peat from the Maunachira channel-swamp system, Okavango Delta, Botswana

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, T.S.; McIver, J.R.; Cairncross, B.; Ellery, W.N.; Ellery, K.

    1989-05-01

    The Okavango Delta is a large (18000 km/sup 2/), low gradient (1:3600), alluvial fan situated in the semi-arid Kalahari basin of northern Botswana. Seasonal floodwaters from tropical Angola disperse on the fan creating both perennial (6000 km/sup 2/) and seasonal (7000 to 12000 km/sup 2/) swamps. Ninety-five percent of this water is lost annually by evapotranspiration. Organic rich sediment (peat) is a major sediment of the perennial swamps. Peat formation commences during senescence of the plants, when certain nutrients are recycled while others are lost by rainwater leaching. Further changes in chemistry occur during subaqueous decay of the plants which involve both gains and losses of constituents. Decaying plants trap detrital mineral matter which becomes an integral part of the peat. The main sources and forms of inorganic matter in the peat are: allochthonous kaolinite (40%) and quartz (20%) and both allochthonous and autochthonous phytolithic silica (30%). several inorganic components (Fe, K, P, Na, Ca and Mg) which make up the remaining 10% are associated with the organic fraction. Ion exchange plays only a minor part in their uptake and it seems that these metals are taken up during bacterial activity in the peat. The weight proportion of inorganic matter (ash) decreases downstream, mainly due to a decrease in allochthonous mineral matter. Volume percentage also decreases but is low throughout, generally less than five percent. This study has revealed that the low-quantity allochthonous mineral matter is the main reason for the long-term survival of this ecosystem. Uptake of soluble ions by the peat is important in off-setting evaporative concentration of metals. 36 refs., 13 figs., 7 tabs.

  11. Ground survey of red lechwe in the Linyanti swamps and Chobe floodplains, northern Botswana

    Directory of Open Access Journals (Sweden)

    Phemelo Gadimang

    2017-05-01

    Full Text Available A ground survey of red lechwe was carried out in the Linyanti swamps and the Chobe floodplains of northern Botswana in the dry and wet seasons of 2012 and 2013, respectively. We documented numbers, sex ratio and age structure of red lechwe within the linear strips of 25 km × 300 m along the Linyanti swamps and the Chobe floodplains. Results indicated a significant difference in the numbers of red lechwe between sites and seasons. About 66 and 755 red lechwe were estimated for Chobe in the dry and wet season, respectively, with 343 and 261 of them estimated for Linyanti in the dry and wet season, respectively. In Chobe, the red lechwe densities varied widely between seasons (9 red lechwe/km2 – 101 red lechwe/km2 compared with Linyanti, where the densities did not vary much between seasons (35 red lechwe/km2 – 46 red lechwe/km2 . The lower densities of red lechwe in Chobe in the dry season when compared with the wet season suggest a possible seasonal shift in the distribution of red lechwe to the nearby Zambezi floodplains in Namibia.Conservation implications: The higher number of red lechwe in the Chobe floodplains in the wet season indicates the potential of the floodplains as a habitat for this species in that season. The dry season shift in the distribution of red lechwe in Chobe presents an opportunity for local communities in Namibia to engage in tourism, whereas the return of the red lechwe to the floodplains in the wet season ensures protection of the animals as well as boosts the tourism potential of the Chobe National Park.

  12. 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

  13. 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

  14. 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...

  15. 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...

  16. 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.

  17. 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

  18. 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.

  19. 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...

  20. 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...

  1. 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...

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. Summary Report for 2003-2004 Phase 1 Archaeological Survey of the United States Fish and Wildlife Service's Great Dismal Swamp National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In February 2004, the United States National Park Service (USNPS) recognized the significance of the United States Fish and Wildlife Service's Great Dismal Swamp...

  9. Ecology and Physiology of a Black Bear Population in Great Dismal Swamp and Reproductive Physiology in the Captive Female Black Bear

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This study was designed to provide information on demographics and ecology of the black bear population in Great Dismal Swamp National Wildlife Refuge for the...

  10. Contaminants in white-tailed deer tissue from the Great Swamp National Wildlife Refuge Morris and Somerset Counties, New Jersey: Results of 1988 sampling and analysis

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — White-tailed deer (Odocoileus virginianus) tissues were sampled during the December, 1988, public deer hunt at the Great Swamp National Wildlife Refuge (GSNWR) to...

  11. Contaminants in fish and sediments of the Great Swamp National Wildlife Refuge, Morris County, New Jersey: A 10-year follow-up investigation

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Located in Morris County, New Jersey about 25 miles west of New York City's Time Square, the U.S. Fish & Wildlife Service's (Service) Great Swamp National...

  12. Hydrography - HYDROGRAPHY_HIGHRES_WATERBODYDISCRETE_NHD_USGS: Lakes, Ponds, Reservoirs, Swamps, and Marshes in Watersheds of Indiana (U. S. Geological Survey, 1:24,000, Polygon Shapefile)

    Data.gov (United States)

    NSGIC State | GIS Inventory — HYDROGRAPHY_HIGHRES_WATERBODYDISCRETE_NHD_USGS.SHP is a polygon shapefile that contains features of lakes, ponds, reservoirs, swamps and marshes in watersheds in and...

  13. TALL HERB SPRUCE FORESTS AS CLIMAX COMMUNITIES ON LOWLAND SWAMPS OF BRYANSK POLESIE

    Directory of Open Access Journals (Sweden)

    O. I. Evstigneev

    2017-09-01

    Full Text Available Nettle grey alder forests are a dominant forest type on lowland swamps in the Bryansk Polesie. They are formed as a result of repeated cuttings in the place of tall herb spruce forests. Tall herb spruce forests are very rare communities in the vegetation cover in this area due to clear cutting, melioration and peat extraction. An assessment of the succession status of tall herb spruce forests and nettle grey alder forests was carried out in this paper. The criteria of climax state and succession state of communities, developed for Eastern European forests, were used. These criteria are based on the degree of intensity of the following signs in the community: 1 the completeness of species composition of tree synusia; 2 the ontogenetic structure of tree species cenopopulation; 3 the gap-mosaic stand structure; 4 the diversity of microsites in soil cover; 5 the completeness of species composition and ecological-coenotic diversity of vascular species. We showed that tall herb spruce forest, as opposed to black alder forest, is close to communities of the climax type. This is evidenced by the following features of cenosis: firstly, all tree species in the area that covers the Bryansk Polesie and that are able to grow on lowland swamps are represented in the spruce forest (Alnus glutinosa, Betula pubescens, Fraxinus excelsior, Padus avium, Picea abies, Salix pentandra, Sorbus aucuparia, Ulmus glabra. Secondly, a steady turnover of generations is carried out in the cenopopulations of main edificators (Picea abies and Alnus glutinosa. This is evidenced by the complete and left-sided structure of their ontogenetic spectrum. Thirdly, a system of asynchronously developing gaps (parcels, which are formed on the site of old tree falls, is formed in the community. This ensures the continuous renewal of spruce and alder populations and creates conditions for the regeneration of other tree species. Fourthly, the structure of biogenic microsites has been formed

  14. 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

  15. 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...

  16. 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...

  17. 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...

  18. 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....

  19. 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...

  20. LOWEST POSSIBLE FELLING TECHNIQUE FOR INCREASING UTILIZATION OF RENGHAS (Gluta renghas L. WOOD AT A PEAT SWAMP FOREST

    Directory of Open Access Journals (Sweden)

    Sona Suhartana

    2006-07-01

    Full Text Available This study was carried out in 2005 at a peat swamp forest company in Jambi. The aim of this study was to find out a technique to increase the utilization of renghas wood in a peat swamp forest by implementing the lowest possible felling technique (LPFT and  the conventional felling technique (CFT. Data collected in this study were: working time, log volume, waste volume, productivity, efficiency, stump height and felling cost. Two data categories were analyzed with respect to their possible differences by using a t-test. The study showed that the implementation of LPFT produced better results compared to that of CFT which was indicated by: (1 Felling productivity increased to 5.220 m3/hour, (2 Felling cost decreased Rp 341/m3, (3 Felling efficiency increased 3.2%, and (4 The average stump heights were 41.2 cm for LPFT and 67.5 cm for CFT.

  1. Water, sanitation and hygiene in wetlands. A case study from the Ewaso Narok Swamp, Kenya.

    Science.gov (United States)

    Anthonj, Carmen; Rechenburg, Andrea; Kistemann, Thomas

    2016-10-01

    Wetlands can be both a blessing and a curse. They are beneficial sources of safe water and nutrition and places from which humans derive their livelihoods. At the same time, wetlands are known to be sources of disease-causing microorganisms and invertebrates that can threaten human health. Safe water, sanitation and personal hygiene (WASH) are crucial preconditions for the prevention of disease transmission. And of special importance for people living in wetlands, depending on and being exposed to them. WASH should be prioritized especially in those wetlands that are subject to intensive use, that have a poor sanitation infrastructure, and which at the same time only provide limited water resources. However, despite this critical importance, WASH in wetlands is not well characterized in literature. This study therefore aimed at providing insights into the water, sanitation and hygiene conditions and behavioural determinants of households in wetlands by presenting the case of a rural wetland in East Africa. The mixed method approach included a broad set of empirical data collected during a household survey (n=400), an observational WASH assessment (n=397) and in-depth interviews (n=20) conducted from January to March 2015 in Ewaso Narok Swamp in Kenya. Different user groups of the wetland were targeted. The study in Ewaso Narok Swamp showed that wetland users' water supply and storage, sanitation and personal hygiene conditions were inadequate for large parts of the community and significantly differed between groups. Whereas the WASH conditions of people working in the service sector were rather positive, for pastoralists, they were correspondingly negative. The WASH behaviour was also perceived to be inadequate influenced by a variety of determining factors. The observational index as applied in this study indicated to be a valuable, rapid and efficient tool for assessing domestic WASH and for detecting differences between different groups in wetlands. Combined

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. Factors affecting oxidative peat decomposition due to land use in tropical peat swamp forests in Indonesia.

    Science.gov (United States)

    Itoh, Masayuki; Okimoto, Yosuke; Hirano, Takashi; Kusin, Kitso

    2017-12-31

    The increasing frequency of fire due to drainage of tropical peatland has become a major environmental problem in Southeast Asia. To clarify the effects of changes in land use on carbon dioxide emissions, we measured oxidative peat decomposition (PD) at different stages of disturbance at three sites in Central Kalimantan, Indonesia: an undrained peat swamp forest (UF), a heavily drained peat swamp forest (DF), and a drained and burned ex-forest (DB). PD exhibited seasonality, being less in the wet season and greater in the dry season. From February 2014 to December 2015, mean PD (±SE) were 1.90±0.19, 2.30±0.33, and 1.97±0.25μmolm(-2)s(-1) at UF, DF, and DB, respectively. The groundwater level (GWL) was a major controlling factor of PD at all sites. At UF and DF, PD and GWL showed significant quadratic relationships. At DB, PD and GWL showed significant positive and negative relationships during the dry and wet seasons, respectively. Using these relationships, we estimated annual PD from GWL data for 2014 and 2015 as 698 and 745gCm(-2)yr(-1) at UF (mean GWL: -0.23 and -0.39m), 775 and 825gCm(-2)yr(-1) at DF (-0.55 and -0.59m), and 646 and 748gCm(-2)yr(-1) at DB (-0.22 and -0.62m), respectively. The annual PD was significantly higher in DF than in UF or DB, in both years. Despite the very dry conditions, the annual PD values at these sites were much lower than those reported for tropical peat at plantations (e.g., oil palm, rubber, and acacia). The differences in the relationship between PD and GWL indicate that separate estimations are required for each type of land. Moreover, our results suggest that PD can be enhanced by drainage both in forests and at burned sites. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. American black bears and bee yard depredation at Okefenokee Swamp, Georgia

    Science.gov (United States)

    Clark, J.D.; Dobey, S.; Masters, D.V.; Scheick, B.K.; Pelton, M.R.; Sunquist, M.E.

    2005-01-01

    We studied American black bears (Ursus americanus), on the northwest periphery of Okefenokee Swamp in southeast Georgia, to assess landowner attitudes toward bears, estimate the extent of damage to commercial honey bee operations by bears, and evaluate methods to reduce bear depredations to apiaries. We collected 8,351 black bear radiolocations and identified 51 bee yards on our study area. Twenty-seven of 43 home ranges contained ≥1 bee yard, averaging 11.3 and 5.1 bee yards/home range of males (n = 7) and females (n = 20), respectively. From 1996 to 1998, we documented 7 instances of bears raiding bee yards within our study area and 6 instances in adjacent areas. All but 1 of the 13 raided yards were enclosed by electric fencing. In the 12 cases of damage to electrically fenced yards, however, the fences were not active because of depleted batteries. Based on compositional analysis, bear use of areas 800–1,400 m from bee yards was disproportionately greater than use 0–800 m from bee yards. Bears disproportionately used bay (red bay: Persea borbonia, loblolly bay: Gordonia lasianthus, and southern magnolia: Magnolia virginia), gum (water tupelo: Nyssa aquatic and black gum: N. sylvatica), and cypress (Taxodium spp.) and loblolly bay habitats, however, compared with slash pine (Pinus elliottii) or pine–oak (Quercus spp.), where bee yards usually were placed. The distribution of bear radiolocations likely reflected the use of those swamp and riparian areas, rather than avoidance of bee yards. Distances to streams from damaged bee yards (x̄ = 1,750 m) were less than from undamaged yards (x̄ = 4,442 m), and damaged bee yards were closer to unimproved roads (x̄ = 134 m) than were undamaged bee yards (x̄ = 802 m). Our analysis suggests that bee yard placement away from bear travel routes (such as streams and unimproved roads) can reduce bear depredation problems. Our results strongly indicate that working electric fences are effective deterrents to bear

  9. The Munchausen paradigm for deprived neighbourhoods: pulling yourself out of the swamp of deprivation

    Directory of Open Access Journals (Sweden)

    Jeannette Nijkamp

    2017-06-01

    Full Text Available The Munchausen paradigm for deprived neighbourhoods: pulling yourself out of the swamp of deprivation Since the 1980s, many initiatives have attempted to tackle the deprivation currently experienced in South Rotterdam. Efforts have been made to attract creative workers and, in a counter-reaction, other initiatives have aimed to encourage the creative talents of poorer residents to strengthen their economic position. One example of this is Freehouse, which has established projects in the Afrikaanderwijk, including a neighbourhood cooperative. Our article addresses two questions: 1 What are the effects of the Freehouse projects on the economic position of residents of the Afrikaanderwijk? and 2 Which insights do our results provide into the possible effects of local government policies that rely on citizens playing an active role? Although the economic effects of the projects were limited, our study reveals that citizens’ initiatives, such as the Afrikaander Cooperative, can help residents gain employment. In order to succeed, these initiatives should not be hindered by obstructive regulations, and they should include input from the residents who function as staff. However, in deprived neighbourhoods, many residents require support to be able to contribute to citizens’ initiatives, and cannot be expected to act like Baron Münchausen and pull themselves out of the swamp of deprivation by their own hair. Het Münchausen paradigma voor achterstandswijken: jezelf uit het moeras van achterstand trekken Sinds de jaren 80 hebben veel initiatieven geprobeerd het achterstandsniveau in Rotterdam Zuid te verminderen. Verschillende initiatieven waren gericht op het aantrekken van creatieve professionals. Als tegenreactie stimuleerden andere initiatieven de creatieve talenten van arme wijkbewoners teneinde hun economische positie te versterken. Een voorbeeld hiervan is Freehouse, dat projecten in de Afrikaanderwijk startte, waaronder de oprichting van

  10. 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.

  11. 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

  12. 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.

  13. Assessment of semen quality in Swamp Buffalo AI Bulls in Thailand

    Directory of Open Access Journals (Sweden)

    S. Koonjaenak

    2010-02-01

    Full Text Available Characteristic of Thai swamp buffalo bulls semen used for artificial insemination (AI in Thailand, aspects relevance in freezing and thawing of semen are review. Semen and sperm characteristics were evaluated included sperm count, motility (assessed subjectively and by CASA, morphology (using phase-contrast light microscopy and SEM, plasma membrane integrity (PMI (using a hypo-osmotic swelling test [HOST] and SYBR- 14/propidium iodide [PI], plasma membrane stability (PMS (using Annexin-V/PI and deoxyribonucleic acid (DNA integrity (using SCSA and flow cytometry [FCM]. The average ejaculate volume was about 3.0–4.0 mL, with good viability (PMI measured by the HOST and motility (>65% and >70%, respectively. Sperm concentration ranged from 1.1 to 1.2 billion/mL, being also affected by bull age. Whereas semen quality (including sperm output, pH and initial sperm motility did not differ between the seasons. Few spermatozoa (<15%/ ejaculate had abnormal morphology with abnormalities resembling those in other bovidae. In FT semen, PMI (using SYBR-14/PI and PMS were highest in winter. Across seasons, ~50% of post-thaw spermatozoa depicted linear motility, a proportion that decreased to ~35% during incubation (38oC for 60 minutes, without marking any seasonal difference. The sperm DNA was hardly damaged (with <3% fragmentation, expressed as DNA fragmentation index [DFI], among seasons.

  14. Restoration and Management of a Degraded Baldcypress Swamp and Freshwater Marsh in Coastal Louisiana

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    Rachael G. Hunter

    2016-02-01

    Full Text Available The Central Wetlands Unit (CWU, covering 12,000 hectares in St. Bernard and Orleans Parishes, Louisiana, was once a healthy baldcypress–water tupelo swamp and fresh and low salinity marsh before construction of levees isolated the region from Mississippi River floodwaters. Construction of the Mississippi River Gulf Outlet (MRGO, which funneled saltwater inland from the Gulf of Mexico, resulted in a drastic ecosystem change and caused mortality of almost all trees and low salinity marsh, but closure of the MRGO has led to decreases in soil and surface water salinity. Currently, the area is open water, brackish marsh, and remnant baldcypress stands. We measured hydrology, soils, water and sediment chemistry, vegetation composition and productivity, accretion, and soil strength to determine relative health of the wetlands. Vegetation species richness is low and above- and belowground biomass is up to 50% lower than a healthy marsh. Soil strength and bulk density are low over much of the area. A baldcypress wetland remains near a stormwater pumping station that also has received treated municipal effluent for about four decades. Based on the current health of the CWU, three restoration approaches are recommended, including: (1 mineral sediment input to increase elevation and soil strength; (2 nutrient-rich fresh water to increase productivity and buffer salinity; and (3 planting of freshwater forests, along with fresh and low salinity herbaceous vegetation.

  15. A Review of the Relative Merits of Conserving, Using, or Draining Papyrus Swamps

    Science.gov (United States)

    Maclean, Ilya M. D.; Boar, Rosalind R.; Lugo, Charles

    2011-02-01

    Wetlands are a vital resource, particularly in Africa where livelihoods are closely linked to natural capital. In recent years, extensive drainage has occurred to make way for agriculture. To gain insight into whether drainage is justified, we review the value of African wetlands dominated by Cyperus papyrus in relation to use, conservation and conversion. Evidence suggests that the value derived from low-intensity, multifunctional wetland use far exceeds the value derived from swamp reclamation and generally exceeds that of conservation. At a local level, the main driver of wetland misuse appear to be a breakdown in collaborative management regimes and the main constraint on wetland use, the value of labor and selling-times. Local drivers are linked to regional factors such as the lack of coordinated wetland policies and difficulties in ensuring that legislation is absorbed by all sectors of society. We highlight opportunities for ensuring more effective collaborative management and legislation communication, which capitalize on existing governance structures. In contrast to predictions by Hardin's Tragedy of the Commons model, we argue that effective wetland management is best achieved by preventing privatization and promoting common property management regimes. We also argue that poverty and income inequity are more important drivers of unsustainable resource use than environmental managers commonly acknowledge.

  16. ADVANCED LAND COVER MAPPING OF TROPICAL PEAT SWAMP ECOSYSTEM USING AIRBORNE DISCRETE RETURN LIDAR

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    Solichin Manuri

    2017-02-01

    Full Text Available The ability to better understand tropical peat ecosystems for restoration and climate change mitigation is often hampered by the lack of availability accurate and detailed data on vegetation cover and hydrologys, which is typically only derived from detailed and high-resolution imaging or field-based measurements. The aims of this study were to explore the potential advantage of airborne discrete-return lidar for mapping of forest cover in peat swamp forests. We used 2.8 pulse.m-1 lidar and the associated 1-m DTM derived from an airborne platform. The lidar dataset fully covered a 120 thousand hectare protection forest in Central Kalimantan. We extracted maximum vegetation heights in 5-m grid resolution to allow detailed mapping of the forest. We followed forest definition from FAO for forest and non-forest classification. We found that lidar was able to capture detail variation of canopy height in high-resolution, thus provide more accurate classification. A comparison with existing maps suggested that the lidar-derived vegetation map was more consistent in defining canopy structure of the vegetation, with small standard deviations of the mean height of each class.

  17. Identification and Characterization of Reference Genes for Normalizing Expression Data from Red Swamp Crawfish Procambarus clarkii

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    Hucheng Jiang

    2015-09-01

    Full Text Available qRT-PCR is a widely used technique for rapid and accurate quantification of gene expression data. The use of reference genes for normalization of the expression levels is crucial for accuracy. Several studies have shown that there is no perfect reference gene that is appropriate for use in all experimental conditions, and research on suitable reference genes in red swamp crawfish (Procambarus clarkii is particularly scarce. In this study, eight commonly used crustacean reference genes were chosen from P. clarkii transcriptome data and investigated as potential candidates for normalization of qRT-PCR data. Expression of these genes under different experimental conditions was examined by qRT-PCR, and the stability of their expression was evaluated using three commonly used statistical algorithms, geNorm, NormFinder and BestKeeper. A final comprehensive ranking determined that EIF and 18S were the optimal reference genes for expression data from different tissues, while TBP and EIF were optimal for expression data from different ovarian developmental stages. To our knowledge, this is the first systematic analysis of reference genes for normalization of qRT-PCR data in P. clarkii. These results will facilitate more accurate and reliable expression studies of this and other crustacean species.

  18. Waste drilling-fluid-utilising microorganisms in a tropical mangrove swamp oilfield location

    Energy Technology Data Exchange (ETDEWEB)

    Benka-Coker, M.O.; Olumagin, A. [Benin Univ. (Nigeria). Dept. of Microbiology

    1995-12-31

    Waste drilling-fluid-utilising microorganisms were isolated from drilling-mud cuttings, soil and creek water from a mangrove swamp oilfield location in the Delta area of Nigeria using waste drilling-fluid as the substrate. Eighteen bacterial isolates obtained were identified as species of Staphylococcus, Acinetobacter, Alcaligenes, Serratia, Clostridium, Enterobacter, Klebsiella, Nocardia, Bacillus, Actinomyces, Micrococcus and Pseudomonas, while the genera of fungi isolated were Penicillium, Cladosporium and Fusarium. Even though drilling-fluid-utilising genera were in higher numbers in the soil than in the two other sources examined, the percentages of the total heterotrophic bacteria that utilised waste drilling-fluid were 6.02 in the drilling-mud cuttings, 0.83 in creek water and 0.42 in soil. The screen tests for biodegradation potential of the bacterial isolates showed that, even though all the isolates were able to degrade and utilise the waste fluid for growth, species of Alcaligenes and Micrococcus were more active degraders of the waste. The significance of the results in environmental management in oil-producing areas of Nigeria is discussed. (Author)

  19. Effect of Combined Probiotics (Saccharomyces cerevisae + Candida utilis and Herbs on Carcass Characteristics of Swamp Buffalo

    Directory of Open Access Journals (Sweden)

    P Mahyuddin

    2010-05-01

    Full Text Available A feedlot trial was conducted to study the effect of probiotics + herbs on carcass characteristics. Thirty male swamp buffaloes aged 2–2.5 years with the average body weight of 297 kg were used in this trial. They were fattened for 75 days to reach a slaughter weight of around 350–400 kg. They were divided into two groups of 15 animals in each group, and were placed in a shaded paddock. The groups were the control and the treated animals. The treated animals were given a supplementation containing combined yeasts (Saccharomyces cerevisae and Candida utilis, and herbs. All animals were fed basal diet of ammoniated rice straw and commercial concentrate with a ratio of 10: 90. There was no effect of probiotics+herbs on live weight gain, percentage of carcass, dressing, meat and by products, back fat thickness and eye muscle area. Addition of probiotics+herbs increased proportion of bone, reduced meat : bone ratio, body fat and proportion of offal. Although body fat content was reduced by the treatment, the compositions of fat were similar between the control and treated animals. (Animal Production 12(2: 69-73 (2010Key Words: buffalo, feedlot, yeast, carcass

  20. Impact of logging on a mangrove swamp in South Mexico: cost / benefit analysis

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    Cristian Tovilla Hernández

    2001-06-01

    Full Text Available Environmental changes caused by logging in a mangrove swamp were studied in Barra de Tecoanapa, Guerrero, Mexico. Original forest included Rhizophora mangle, Laguncularia racemosa, Avicennia germinans and halophytic vegetation, and produced wood (164.03 m3/ha and organic matter (3.9 g/m2/day. A total of 3.5 tons of wood per year were harvested from this area. Later, an average of 2 555 kg of maize per planting cycle were obtained (market value of 88 USD. Succession when the area was abandoned included strictly facultative and glycophyte halophytes (16 families, Cyperaceae and Poaceae were the best represented. After logging, temperatures increased 13 °C in the soil and 11°C in the air, whereas salinity reached 52 psu in the dry season. These modified soil color and sand content increased from 42.6 to 63.4%. Logging was deleterious to species, habitat, biogeochemical and biological cycles, organic matter production, seeds, young plants, genetic exchange conservation of soil and its fertility, coastal protection, and aesthetic value; 3 000 m2 had eroded as the river advanced towards the deforested area (the cost/benefit analysis showed a ratio of 246: 1. There was long-term economic loss for the community and only 30% of the site has recovered after five years.

  1. [Egg size variation in egrets and herons (Aves: Ardeidae) nesting in Birama's swamp, Cuba].

    Science.gov (United States)

    Denis Avila, Dennis

    2015-03-01

    Intraclutch egg size variation in birds depends on many ecological factors and on the evolutive history of each species. In wading birds, a trend to smaller eggs with laying order has been described, but comparative reports are scarce. In this study, egg size variation patterns were described for nine Egrets and Heron species nesting in Birama' Swamp, Cuba. The patterns were described using external dimensions of 3142 eggs from 1875 nests of Butorides virescens, Bubulcus ibis, Ardea alba, Nycticorax nycticorax, Nyctanassa violacea and four Egretta species, taken in the field between 1998 and 2006. Results showed that eggs were 4.9-10% of adult weight and had volume variation coefficients between 6-9%. There were no general and consistent interspecies relationship between clutch size and egg sizes. Average volumes tend to get smaller with laying order, but it is not statistically detectable in Butorides and Bubulcus. Last egg was between 0.2% and 15% smaller than the first, showing an inverse relationship with it. Intraclutch asymmetry is light in E. thula and fluctuating around null in Bubulcus. Size only predicted laying or hatching order for the last egg, in nests with more than two eggs, with 72.4% of confidence.

  2. Swamp cancer: a case of human pythiosis and review of the literature.

    Science.gov (United States)

    Hilton, R E; Tepedino, K; Glenn, C J; Merkel, K L

    2016-08-01

    Pythiosis is an infection caused by the aquatic oomycete Pythium insidiosum. Commonly known as 'swamp cancer' in veterinary pathology, pythiosis is now considered an emerging human disease associated with significant morbidity and mortality. However, because clinical information is limited, many healthcare providers, including dermatologists, are unfamiliar with this diagnosis. To increase awareness of this life-threatening infection, a case of cutaneous pythiosis is presented. We describe a middle-aged man with acute myeloid leukaemia who presented with necrotizing haemorrhagic plaques on his thighs after a weekend of freshwater boating. Histological examination of a biopsy specimen showed invasive fungal hyphae associated with dense perivascular inflammation and vessel damage. Diagnostic testing on tissue culture revealed growth of P. insidiosum. Despite multiple debridements and antifungal therapy, the patient died within 2 weeks of presentation. There are four clinical presentations reported in human pythiosis. Pythium insidiosum infection should be considered in any patient with a suggestive exposure history and fungal elements found on histological examination or in culture. Identification of the organism can be difficult, so polymerase chain reaction and serological assays can be useful in making a diagnosis. To improve clinical outcomes, early combination therapy with antifungals and surgery is needed. © 2016 British Association of Dermatologists.

  3. High methane emissions from restored Norway spruce swamps in southern Finland over one growing season

    Directory of Open Access Journals (Sweden)

    M. Koskinen

    2016-02-01

    Full Text Available Forestry-drained peatlands in the boreal region are currently undergoing restoration in order to bring these ecosystems closer to their natural (undrained state. Drainage affects the methane (CH4 dynamics of a peatland, often changing sites from CH4 sources to sinks. Successful restoration of a peatland would include restoration of not only the surface vegetation and hydrology, but also the microbial populations and thus CH4 dynamics. As a pilot study, CH4 emissions were measured on two pristine, two drained and three restored boreal spruce swamps in southern Finland for one growing season. Restoration was successful in the sense that the water table level in the restored sites was significantly higher than in the drained sites, but it was also slightly higher than in the pristine sites. The restored sites were surprisingly large sources of CH4 (mean emissions of 52.84 mg CH4 m-2 d-1, contrasting with both the pristine (1.51 mg CH4 m-2 d-1 and the drained sites (2.09 mg CH4 m-2 d-1. More research is needed to assess whether the high CH4 emissions observed in this study are representative of restored spruce mires in general.

  4. Firing Room Remote Application Software Development & Swamp Works Laboratory Robot Software Development

    Science.gov (United States)

    Garcia, Janette

    2016-01-01

    The National Aeronautics and Space Administration (NASA) is creating a way to send humans beyond low Earth orbit, and later to Mars. Kennedy Space Center (KSC) is working to make this possible by developing a Spaceport Command and Control System (SCCS) which will allow the launch of Space Launch System (SLS). This paper's focus is on the work performed by the author in her first and second part of the internship as a remote application software developer. During the first part of her internship, the author worked on the SCCS's software application layer by assisting multiple ground subsystems teams including Launch Accessories (LACC) and Environmental Control System (ECS) on the design, development, integration, and testing of remote control software applications. Then, on the second part of the internship, the author worked on the development of robot software at the Swamp Works Laboratory which is a research and technology development group which focuses on inventing new technology to help future In-Situ Resource Utilization (ISRU) missions.

  5. Tower-Based Validation and Improvement of MODIS Gross Primary Production in an Alpine Swamp Meadow on the Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Ben Niu

    2016-07-01

    Full Text Available Alpine swamp meadow on the Tibetan Plateau is among the most sensitive areas to climate change. Accurate quantification of the GPP in alpine swamp meadow can benefit our understanding of the global carbon cycle. The 8-day MODerate resolution Imaging Spectroradiometer (MODIS gross primary production (GPP products (GPP_MOD provide a pathway to estimate GPP in this remote ecosystem. However, the accuracy of the GPP_MOD estimation in this representative alpine swamp meadow is still unknown. Here five years GPP_MOD was validated using GPP derived from the eddy covariance flux measurements (GPP_EC from 2009 to 2013. Our results indicated that the GPP_EC was strongly underestimated by GPP_MOD with a daily mean less than 40% of EC measurements. To reduce this error, the ground meteorological and vegetation leaf area index (LAIG measurements were used to revise the key inputs, the maximum light use efficiency (εmax and the fractional photosynthetically active radiation (FPARM in the MOD17 algorithm. Using two approaches to determine the site-specific εmax value, we suggested that the suitable εmax was about 1.61 g C MJ−1 for this alpine swamp meadow which was considerably larger than the default 0.68 g C MJ−1 for grassland. The FPARM underestimated 22.2% of the actual FPAR (FPARG simulated from the LAIG during the whole study period. Model comparisons showed that the large inaccuracies of GPP_MOD were mainly caused by the underestimation of the εmax and followed by that of the undervalued FPAR. However, the DAO meteorology data in the MOD17 algorithm did not exert a significant affection in the MODIS GPP underestimations. Therefore, site-specific optimized parameters inputs, especially the εmax and FPARG, are necessary to improve the performance of the MOD17 algorithm in GPP estimation, in which the calibrated MOD17A2 algorithm (GPP_MODR3 could explain 91.6% of GPP_EC variance for the alpine swamp meadow.

  6. Holocene palaeoclimate and sea level fluctuation recorded from the coastal Barker Swamp, Rottnest Island, south-western Western Australia

    Science.gov (United States)

    Gouramanis, C.; Dodson, J.; Wilkins, D.; De Deckker, P.; Chase, B. M.

    2012-10-01

    The Holocene palaeoclimatic history of south-western Western Australia (SWWA) has received little attention compared to south-eastern Australia, and this has resulted in conflicting views over the impact of climate variability in the region. We present here a well-dated, high-resolution record from two overlapping sediment cores obtained from the centre of Barker Swamp, Rottnest Island, offshore Perth. The records span the last 8.7 ka, with the main lacustrine phase occurring after 7.4 ka. This site preserves both pollen and several ostracod taxa. The pollen record suggests a long-term shift from the early-mid Holocene to the late Holocene to drier conditions with less shrubland and more low-ground cover and less fire activity. A salinity transfer function was developed from ostracod faunal assemblage data and trace metal ratios (Mg/Ca, Sr/Ca and Na/Ca) and stable isotopes (δ18O and δ13C) analysed on selected ostracod valves. These provide a detailed history of evaporation/precipitation (E/P) differences that clearly shows that the SWWA region was subjected to significant climatic shifts over the last 7.4 ka, with a broad shift towards increased aridity after 5 ka. The swamp ranged from fresh to saline as recorded in the ostracod valve chemistry and the independently-derived salinity transfer function. The ostracod record also indicates that a sea-level highstand occurred between ca. 4.5 and 4.3 ka, with probable step-wise increases at 6.75, 6.2, and 5.6 ka, with the last vestiges of salt water intrusion at ca. 1 ka. After about 2.3 ka, the fresh, groundwater lens that underlies the western portion of the island intersected the swamp depression, influencing the hydrology of the swamp. The broad climatic changes recorded in Barker Swamp are also compared with data from southern South Africa, and it is suggested that the Southern Annular Mode appears to have been the dominant driver in the climate of these regions and that the Indian Ocean Dipole is of little

  7. 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).

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Characterizing the Status (Disturbed, Hybrid or Novel) of Swamp Forest Fragments in a Caribbean Ramsar Wetland: The Impact of Anthropogenic Degradation and Invasive Plant Species

    Science.gov (United States)

    Prospere, Kurt; McLaren, Kurt P.; Wilson, Byron

    2016-10-01

    The last remaining Amazonian-type swamp forest fragments in Black River Lower Morass, Jamaica, have been subjected to a myriad of anthropogenic disturbances, compounded by the establishment and spread of several invasive plant species. We established 44 permanent sample plots (covering 3.92 ha) across 10 of these swamp forest fragments and sampled all non-woody plants and all trees ≥2 cm DBH found in the plots. These data were used to (1) identify thresholds of hybridity and novelty, (2) derive several diversity and structural descriptors used to characterize the swamp forest fragments and (3) identify possible indicators of anthropogenic degradation. These were incorporated into a framework and used to determine the status of the swamp forest fragments so that appropriate management and conservation measures can be implemented. We recorded 43 woody plant species (9 endemic, 28 native and 4 non-native) and 21 non-tree species. The composition and structure of all the patches differed significantly due to the impact of the herbaceous invasive plant Alpinia allughas, the presence and diversity of other non-native plants, and differing intensities of anthropogenic disturbance (e.g., burning, cutting and harvesting of non-timber forest products). We ranked forest patches along a continuum representing deviations from a historical proxy (least disturbed) swamp forest to those with dramatically altered structural and floristic attributes (=novel swamp forests). Only one fragment overrun with A. allughas was classified as novel. If effective conservation and management does not come to the BRLM, the remaining swamp forest fragments appear doomed to further degradation and will soon disappear altogether.

  13. TEMPORAL VEGETATION DYNAMICS IN PEAT SWAMP AREA USING MODIS TIME-SERIES IMAGERY: A MONITORING APPROACH OF HIGH-SENSITIVE ECOSYSTEM IN REGIONAL SCALE

    Directory of Open Access Journals (Sweden)

    Yudi Setiawan

    2016-10-01

    Full Text Available Peat swamp area is an essential ecosystem due to high vulnerability of functions and services. As the change of forest cover in peat swamp area has increased considerably, many studies on peat swamp have focused on forest conversion or forest degradation. Meanwhile, in the context of changes in the forestlands are the sum of several processes such as deforestation, reforestation/afforestation, regeneration of previously deforested areas, and the changing spatial location of the forest boundary. Remote sensing technology seems to be a powerful tool to provide information required following that concerns. A comparison imagery taken at the different dates over the same locations for assessing those changes tends to be limited by the vegetation phenology and land-management practices. Consequently, the simultaneous analysis seems to be a way to deal with the issues above, as a means for better understanding of the dynamics changes in peat swamp area. In this study, we examined the feasibility of using MODIS images during the last 14 years for detecting and monitoring the changes in peat swamp area. We identified several significant patterns that have been assigned as the specific peat swamp ecosystem. The results indicate that a different type of ecosystem and its response to the environmental changes can be portrayed well by the significant patterns. In understanding the complex situations of each pattern, several vegetation dynamics patterns were characterized by physical land characteristics, such as peat depth, land use, concessions and others. Characterizing the pathways of dynamics change in peat swamp area will allow further identification for the range of proximate and underlying factors of the forest cover change that can help to develop useful policy interventions in peatland management.

  14. Characterizing the Status (Disturbed, Hybrid or Novel) of Swamp Forest Fragments in a Caribbean Ramsar Wetland: The Impact of Anthropogenic Degradation and Invasive Plant Species.

    Science.gov (United States)

    Prospere, Kurt; McLaren, Kurt P; Wilson, Byron

    2016-10-01

    The last remaining Amazonian-type swamp forest fragments in Black River Lower Morass, Jamaica, have been subjected to a myriad of anthropogenic disturbances, compounded by the establishment and spread of several invasive plant species. We established 44 permanent sample plots (covering 3.92 ha) across 10 of these swamp forest fragments and sampled all non-woody plants and all trees ≥2 cm DBH found in the plots. These data were used to (1) identify thresholds of hybridity and novelty, (2) derive several diversity and structural descriptors used to characterize the swamp forest fragments and (3) identify possible indicators of anthropogenic degradation. These were incorporated into a framework and used to determine the status of the swamp forest fragments so that appropriate management and conservation measures can be implemented. We recorded 43 woody plant species (9 endemic, 28 native and 4 non-native) and 21 non-tree species. The composition and structure of all the patches differed significantly due to the impact of the herbaceous invasive plant Alpinia allughas, the presence and diversity of other non-native plants, and differing intensities of anthropogenic disturbance (e.g., burning, cutting and harvesting of non-timber forest products). We ranked forest patches along a continuum representing deviations from a historical proxy (least disturbed) swamp forest to those with dramatically altered structural and floristic attributes (=novel swamp forests). Only one fragment overrun with A. allughas was classified as novel. If effective conservation and management does not come to the BRLM, the remaining swamp forest fragments appear doomed to further degradation and will soon disappear altogether.

  15. 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.

  16. The effect of peat swamp forest degradation on greenhouse gas fluxes in the Peruvian Amazon

    Science.gov (United States)

    van Lent, Jeffrey; Hergoualc'h, Kristell; Verchot, Louis; van Groeningen, Jan Willem; Oenema, Oene

    2017-04-01

    Carbon-dense peat swamp forests in Peru are recurrently harvested for M. flexuosa fruits, which is typically performed by cutting down entire palms. This research aimed to evaluate how biogeochemical cycles are affected by this type of forest degradation. Total soil respiration (Rs), heterotrophic respiration (Rh), CH4 and N2O fluxes, litterfall and environmental parameters were monitored monthly for two years in an undisturbed (UD), a moderately disturbed (MD), and a highly degraded site (HD). The experimental setup entailed measurements in hollows and hummocks with standing live or dead palms. Rh rates were higher in hummocks than in hollows (UD: 25.9±0.5 and 17.5±0.3, MD: 14.1±1.3 and 12.4±1.2, HD: 26.8±4.7 and 18.8±3.0 kg C-CO2 ha-1 d-1, respectively). Unexpectedly, CH4 fluxes did not vary significantly between hummocks and hollows, whereas N2O fluxes followed the same trend as Rh. GHG fluxes from hummocks with a standing live or a standing dead palm were similar. However, degradation did reduce the relative hummock area (relative areas: 18, 10 and 4% for UD, MD, and HD, respectively). As a result, the overall weighted average Rh in the MD site (12.4±1.6 kg C-CO2 ha-1 d-1) was lower than the UD one (18.4±1.0 kg C-CO2 ha-1 d-1), while litter input was higher (12.2±0.3 and 9.3±0.4 kg d.w. ha-1 d-1in the MD and UD, respectively). The HD site exhibited Rh (17.5±1.2 kg C-CO2 ha-1 d-1) and litter input (9.4±0.2 kg d.w. ha-1 d-1) rates similar to those of the UD site. CH4 fluxes were 0.75±0.10, 0.62±0.08, 0.89±0.05 kg C-CH4 ha-1 d-1 and N2O fluxes 1.7±0.2, 1.2±0.1, 2.0±0.3 g N-N2O ha-1 d-1 in the UD, MD and HD site, respectively. These findings suggest that differentiating hummocks and hollows in GHG flux assessments and accounting for changes in relative hummock areas are essential for evaluating degradation impacts on peat C and N cycling in Amazonian peat swamp forests. These results contribute to building knowledge on emission factors for

  17. Burrowing activity in channel levees: impact of the invasive red swamp crayfish Procambarus clarkii

    Science.gov (United States)

    Solari, L.; Bendoni, M.; Consumi, L.; Haubrock, P.; Inghilesi, A.; Mazza, G.; Torrini, M.; Tricarico, E.

    2016-12-01

    The effect of animal burrowing, as an example of bioturbation on the stability of river levees has been recently raised to the scientific community as a consequence of the levee collapses of Secchia and Foenna rivers in Italy (Camici et al., 2010, 2014; Orlandini et al., 2015). Indeed, these authors showed that the presence of animal burrows is crucial in promoting the collapse of the bank. The American red swamp Crayfish Procambarus clarkii is an invasive species in Europe, mostly introduced for commercial purposes related to livestock. It is rapidly spreading throughout the Italian peninsula due to its plasticity, dispersal capability and high reproduction rate (Souty-Grosset et al., 2016). As well as the negative effects on local biodiversity, it damages the levees of the irrigation channel leading to disastrous collapses, relevant repairing and maintenance costs. In this work, we present an experimental activity where specimens of P. clarkii were monitored while burrowing into a small-scale physical model of an earthen levee, coupled with the mathematical modelling of the variations induced by the burrows on the seepage flow patterns through the levee.Preliminary results show the burrowing structure was quite irregular. Generally, crayfish start burrowing under the water level, developing tunnels (diameter ranging 4-7cm) both horizontally and heading upward, also above the water level. Some tunnels showed one or more circular chambers. The highest burrowing activity was observed during the experiments carried out in summer, when the species has a peak of maximum activity due to the higher temperature. Mathematical modelling shows that, for given boundary conditions and experimental duration, the presence of burrows in the levee raises the phreatic line. Critical conditions for levee integrity may be associated either to the internal erosion and stability of the system of tunnels and to the emergence of the phreatic line of the landside of the levee slope. These

  18. In-depth transcriptome analysis of the red swamp crayfish Procambarus clarkii.

    Directory of Open Access Journals (Sweden)

    Huaishun Shen

    Full Text Available The red swamp crayfish Procambarus clarkii is a highly adaptable, tolerant, and fecund freshwater crayfish that inhabits a wide range of aquatic environments. It is an important crustacean model organism that is used in many research fields, including animal behavior, environmental stress and toxicity, and studies of viral infection. Despite its widespread use, knowledge of the crayfish genome is very limited and insufficient for meaningful research. This is the use of next-generation sequencing techniques to analyze the crayfish transcriptome. A total of 324.97 million raw reads of 100 base pairs were generated, and a total of 88,463 transcripts were assembled de novo using Trinity software, producing 55,278 non-redundant transcripts. Comparison of digital gene expression between four different tissues revealed differentially expressed genes, in which more overexpressed genes were found in the hepatopancreas than in other tissues, and more underexpressed genes were found in the testis and the ovary than in other tissues. Gene ontology (GO and KEGG enrichment analysis of differentially expressed genes revealed that metabolite- and immune-related pathway genes were enriched in the hepatopancreas, and DNA replication-related pathway genes were enriched in the ovary and the testis, which is consistent with the important role of the hepatopancreas in metabolism, immunity, and the stress response, and with that of the ovary and the testis in reproduction. It was also found that 14 vitellogenin transcripts were highly expressed specifically in the hepatopancreas, and 6 transcripts were highly expressed specifically in the ovary, but no vitellogenin transcripts were highly expressed in both the hepatopancreas and the ovary. These results provide new insight into the role of vitellogenin in crustaceans. In addition, 243,764 SNP sites and 43,205 microsatellite sequences were identified in the sequencing data. We believe that our results provide an

  19. Identification and characterization of two arasin-like peptides in red swamp crayfish Procambarus clarkii.

    Science.gov (United States)

    Chai, Lian-Qin; Li, Wan-Wan; Wang, Xian-Wei

    2017-11-01

    Antimicrobial peptides (AMPs) are small effectors in host defense by directly targeting microorganisms or by indirectly modulating immune responses. In the present study, two arasin like AMPs, named as Pc-arasin1 and Pc-arasin2, were identified in red swamp crayfish Procambarus clarkii with sequence similarity to the arasins found in Hyas araneus. Both Pc-arasins consisted of signal peptide, N-terminal proline-rich region and C-terminal region containing four conserved cysteine residues. The similarity of two Pc-arasins was 44.44%, and Pc-arasin2 contained several additional residues in the N-terminus. Multiple alignment of arasin family suggested the conservation of the C-terminus and the variation of the N-terminus of Pc-arasins. Both AMPs were found hemocytes-specific, and the expression could be induced the challenge of bacteria, espeacially by the pathogenic bacterium Aeromonas hydrophila. Knockdown of each Pc-arasin expression by double strand RNA would suppress the host immunity against A. hydrophila, and the commercially synthetic Pc-arasins could rescue the knockdown consequence. Both synthetic peptide showed broad antimicrobial activity towards 3 Gram-positive bacterium and 3 Gram-negative bacterium, and the minimal inhibitory concentrations varied from 6.25 μM to 50 μM. These results presented new data about the sequence, expression and function of arasin family, and emphasized the role of this family in host immune response against bacterial pathogens. The characterization of Pc-arasins also provided potential of therapeutic agent development for disease control in aquaculture based on these two newly identified AMPs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Nocardia rayongensis sp. nov., isolated from Thai peat swamp forest soil.

    Science.gov (United States)

    Tanasupawat, Somboon; Phongsopitanun, Wongsakorn; Suwanborirux, Khanit; Ohkuma, Moriya; Kudo, Takuji

    2016-05-01

    An actinomycete strain, RY45-3T, isolated from a peat swamp forest soil in Rayong Province, Thailand, was characterized using a polyphasic approach. The strain belonged to the genus Nocardia on the basis of morphological, physiological, biochemical and chemotaxonomic properties. Cell-wall peptidoglycan contained meso-diaminopimelic acid. The N-acyl group of muramic acid in the cell wall was glycolyl type. The diagnostic sugars in whole-cell hydrolysates were galactose and arabinose. MK-8 (H4ω-cycl) was the major menaquinone. The major fatty acids were C16 : 0 and C18 : 1ω9c. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. The genomic DNA G+C content was 71 mol%. On the basis of 16S rRNA gene sequence similarity analysis, strain RY45-3T was closely related to Nocardia jiangxiensis JCM 12861T (98.9 %), Nocardia nova JCM 6044T (98.8 %) and Nocardia pseudobrasiliensis JCM 9894T (98.6 %). The strain showed low levels of DNA-DNA relatedness with N. jiangxiensis JCM 12861T, N. nova JCM 6044T and N. pseudobrasiliensis JCM 9894T (range from 3.6 to 55.3 %). On the basis of the phenotypic characteristics and the results mentioned, this strain could be differentiated from closely related type strains and represents a novel species of the genus Nocardia, for which the name Nocardia rayongensis sp. nov. (type strain RY45-3T = JCM 19832T = TISTR 2213T = PCU 334T) is proposed.

  1. Deforestation projections for carbon-rich peat swamp forests of Central Kalimantan, Indonesia.

    Science.gov (United States)

    Fuller, Douglas O; Hardiono, Martin; Meijaard, Erik

    2011-09-01

    We evaluated three spatially explicit land use and cover change (LUCC) models to project deforestation from 2005-2020 in the carbon-rich peat swamp forests (PSF) of Central Kalimantan, Indonesia. Such models are increasingly used to evaluate the impact of deforestation on carbon fluxes between the biosphere and the atmosphere. We considered both business-as-usual (BAU) and a forest protection scenario to evaluate each model's accuracy, sensitivity, and total projected deforestation and landscape-level fragmentation patterns. The three models, Dinamica EGO (DE), GEOMOD and the Land Change Modeler (LCM), projected similar total deforestation amounts by 2020 with a mean of 1.01 million ha (Mha) and standard deviation of 0.17 Mha. The inclusion of a 0.54 Mha strict protected area in the LCM simulations reduced projected loss to 0.77 Mha over 15 years. Calibrated parameterizations of the models using nearly identical input drivers produced very different landscape properties, as measured by the number of forest patches, mean patch area, contagion, and Euclidean nearest neighbor determined using Fragstats software. The average BAU outputs of the models suggests that Central Kalimantan may lose slightly less than half (45.1%) of its 2005 PSF by 2020 if measures are not taken to reduce deforestation there. The relatively small reduction of 0.24 Mha in deforestation found in the 0.54 Mha protection scenario suggests that these models can identify potential leakage effects in which deforestation is forced to occur elsewhere in response to a policy intervention.

  2. How could a freshwater swamp produce a chemical signature characteristic of a saltmarsh?

    Science.gov (United States)

    McCloskey, Terrence; Smith, Christopher G.; Liu, Kam-biu; Marot, Marci E.; Haller, Christian

    2018-01-01

    Reduction–oxidation (redox) reaction conditions, which are of great importance for the soil chemistry of coastal marshes, can be temporally dynamic. We present a transect of cores from northwest Florida wherein radical postdepositional changes in the redox regime has created atypical geochemical profiles at the bottom of the sedimentary column. The stratigraphy is consistent along the transect, consisting of, from the bottom upward, carbonate bedrock, a gray clay, an organic mud section, a dense clay layer, and an upper organic mud unit representing the current saltwater marsh. However, the geochemical signature of the lower organic mud unit suggests pervasive redox reactions, although the interval has been identified as representing a freshwater marsh, an unlikely environment for such conditions. Analyses indicate that this discrepancy results from postdepositional diagenesis driven by millennial-scale environmental parameters. Rising sea level that led to the deposition of the capping clay layer, created anaerobic conditions in the freshwater swamp interval, and isolated it hydrologically from the rest of the sediment column. The subsequent infiltration of marine water into this organic material led to sulfate reduction, the buildup of H2S and FeS, and anoxic conditions. Continued sulfidation eventually resulted in euxinic conditions, as evidenced by elevated levels of Fe, S, and especially Mo, the diagnostic marker of euxinia. Because this chemical transformation occurred long after the original deposition the geochemical signature does not reflect soil chemistry at the time of deposition and cannot be used to infer syn-depositional environmental conditions, emphasizing the importance of recognizing diagenetic processes in paleoenvironmental studies.

  3. Differences in impacts of Hurricane Sandy on freshwater swamps on the Delmarva Peninsula, Mid−Atlantic Coast, USA

    Science.gov (United States)

    Middleton, Beth A.

    2016-01-01

    Hurricane wind and surge may have different influences on the subsequent composition of forests. During Hurricane Sandy, while damaging winds were highest near landfall in New Jersey, inundation occurred along the entire eastern seaboard from Georgia to Maine. In this study, a comparison of damage from salinity intrusion vs. wind/surge was recorded in swamps of the Delmarva Peninsula along the Pocomoke (MD) and Nanticoke (DE) Rivers, south of the most intense wind damage. Hickory Point Cypress Swamp (Hickory) was closest to the Chesapeake Bay and may have been subjected to a salinity surge as evidenced by elevated salinity levels at a gage upstream of this swamp (storm salinity = 13.1 ppt at Nassawango Creek, Snow Hill, Maryland). After Hurricane Sandy, 8% of the standing trees died at Hickory including Acer rubrum, Amelanchier laevis, Ilex spp., and Taxodium distichum. In Plot 2 of Hickory, 25% of the standing trees were dead, and soil salinity levels were the highest recorded in the study. The most important variables related to structural tree damage were soil salinity and proximity to the Atlantic coast as based on Stepwise Regression and NMDS procedures. Wind damage was mostly restricted to broken branches although tipped−up trees were found at Hickory, Whiton and Porter (species: Liquidamabar styraciflua, Pinus taeda, Populus deltoides, Quercus pagoda and Ilex spp.). These trees fell mostly in an east or east−southeast direction (88o−107o) in keeping with the wind direction of Hurricane Sandy on the Delmarva Peninsula. Coastal restoration and management can be informed by the specific differences in hurricane damage to vegetation by salt versus wind.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Nitrogen Dynamics Along a Headwater Stream Draining a Fen, Swamp, and Marsh in a Fractured Dolomite Watershed

    Science.gov (United States)

    Duval, T. P.; Waddington, J. M.

    2009-05-01

    Stream-wetland interaction has been shown to have a significant effect on nutrient cycling and downstream water quality. Additionally, connection to regional groundwater systems can dilute or enrich stream water with a number of dissolved constituents. This study demonstrates the resultant downstream change in dissolved nitrogen species as a hardwater stream emerges from a calcareous aquifer and traverses a calcareous fen, a cedar swamp, and a cattail marsh over two growing seasons, a very dry 2006 and a very wet 2007. Upon emergence at a number of groundwater seeps, the water contained appreciable nitrate levels averaging 2.72±0.42 mg NO3-N L-1, minimal organic nitrogen, and ammonium below detectable levels. Through the gently sloping calcareous fen, with a stream residence time of ~ 5 hours, NO3-N concentration decreases of 0.35 mg L-1 were observed. Concomitantly, stream recharge into the dolomite bedrock depressed stream discharge values significantly, further removing nitrate from the stream system. This resulted in the fen-bedrock system acting as an estimated net sink of 432 kg of NO3-N in the early summer of 2007, for example. In contrast, the hydrological-biogeochemical systems became decoupled through the swamp during the same period, where concentrations increased from 2.58±0.34 mg L-1 entering the swamp to 2.65±0.58 mg L-1 exiting, but streamflow decreased in general by 5 L s- 1. This resulted in the swamp, with its large depression storage, acting as a small net sink of nitrate (75 kg through the early summer), which would not be detected simply from concentration changes. The concentration-discharge relation realigned through the marsh, where significant groundwater entered the wetland, increasing both concentration and discharge, yielding a small export of 93 kg over the same time period. A series of tracer injections in each wetland type will be presented to compare the streamflow- concentration patterns with the measured nutrient spiralling

  11. 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)

  12. 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.

  13. 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.

  14. 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.

  15. 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...

  16. 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...

  17. 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...

  18. 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.

  19. 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...

  20. Recent benthic foraminifera assemblages from mangrove swamp and channels of Abu Dhabi (UAE)

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.; Odeh, Weaam A. S. Al; Paul, Andreas; Song, Jianfeng; Freeman, Mark; Michel, Françoise

    2017-04-01

    Zonation of Recent mangrove environments can be defined using benthic foraminifera, however, little is known about foraminifera from mangrove environments of the Persian/Arabian Gulf. The objective of this study is to produce a detailed micropaleontological and sedimentological analysis to identify foraminiferal associations from mangrove swamps and channels located on the eastern side of Abu Dhabi Island (UAE). Detailed sediment sampling collection in mangal environments of Eastern Abu Dhabi was carried out to assess the distribution of benthic foraminifera in different sedimentary facies in the mangal and in the surrounding natural environments of the upper and lower intertidal area (mud flats and channels). A 100 m transect across a natural channel in a mangal on the eastern side of Abu Dhabi Island was sampled in detail for sedimentological and foraminiferal analysis. Forty-seven samples were collected at 2 meter intervals along the transect in a number of different sedimentary facies including; fine sediment in areas exposed during low tide and close to mangrove trees (Avicennia marina), fine sediment rich in leaf material, coarse sediment in channels, and coarse sediments with a shell lag. At each sampling location environmental parameters were recorded, including water depth, salinity, temperature and pH. Samples collected for foraminiferal analysis were stained in rose Bengal in order to identify living specimens. Samples collected on the mud flat at the margin of the channel show a living foraminiferal assemblage characterised by abundant foraminifera belonging to the genera Ammonia, Elphidium, Cribroelphidium, Triloculina, Quinqueloculina, Sigmoilinita, Spiroloculina, Peneroplis and Spirolina. Samples collected in the lower (wet) intertidal area close to Avicennia marina roots, presented a low-diversity assemblage mostly comprising small-sized opportunistic foraminifera of the genera Ammonia and Cribroelphidium along with rare Triloculina and