Science.gov

Sample records for ocean perch sebastes

  1. Environmental covariates of sablefish (Anoplopoma fimbria) and Pacific ocean perch (Sebastes alutus) recruitment in the Gulf of Alaska

    NASA Astrophysics Data System (ADS)

    Coffin, Brendan; Mueter, Franz

    2016-10-01

    The sablefish (Anoplopoma fimbria) and Pacific ocean perch (POP; Sebastes alutus) fisheries in the Gulf of Alaska (GOA) are both highly lucrative and variable. Determining environmental factors that drive variability in their recruitment may improve our understanding of forces affecting their early life survival, which may be helpful when evaluating management strategies. Here we examine relationships between sablefish and POP recruitment and multiple environmental indices associated with circulation in the GOA. We used hierarchical cluster analysis to determine spatially and seasonally relevant scales for analyzing these relationships. We then used structural equation modeling to examine sequential relationships between large-scale climate variables, regional (eastern and western GOA) environmental variables, and recruitment using both hypothesis-testing and exploratory approaches. Exploratory analyses revealed that sablefish recruitment was positively related to July upwelling-favorable winds and negatively related to late winter freshwater discharge in the eastern GOA during age 1. POP recruitment was negatively related to June upwelling-favorable winds in both regions during ages 0 and 1 and positively related to late spring freshwater discharge throughout the GOA during age 1. These results suggest that upwelling-favorable winds and freshwater discharge may affect recruitment of both species through productivity-related mechanisms, and may additionally affect POP recruitment through advection-related mechanisms. Targeted studies at the appropriate scales are needed to provide greater certainty in the potential mechanisms behind these relationships.

  2. Fate of a perched crystal layer in a magma ocean

    NASA Technical Reports Server (NTRS)

    Morse, S. A.

    1992-01-01

    The pressure gradients and liquid compressibilities of deep magma oceans should sustain the internal flotation of native crystals owing to a density crossover between crystal and liquid. Olivine at upper mantle depths near 250 km is considered. The behavior of a perched crystal layer is part of the general question concerning the fate of any transient crystal carried away from a cooling surface, whether this be a planetary surface or the roof of an intrusive magma body. For magma bodies thicker than a few hundred meters at modest crustal depths, the major cooling surface is the roof even when most solidification occurs at the floor. Importation of cool surroundings must also be invoked for the generation of a perched crystal layer in a magma ocean, but in this case the perched layer is deeply embedded in the hot part of the magma body, and far away from any cooling surface. Other aspects of this study are presented.

  3. 75 FR 69598 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch by Vessels in the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... Zone Off Alaska; Pacific Ocean Perch by Vessels in the Amendment 80 Limited Access Fishery in the...: Temporary rule; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch by vessels.... The 2010 Pacific ocean perch TAC specified for vessels participating in the Amendment 80 limited...

  4. 75 FR 69599 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch by Vessels in the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... Off Alaska; Pacific Ocean Perch by Vessels in the Amendment 80 Limited Access Fishery in the Eastern...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch by vessels participating in.... The 2010 Pacific ocean perch TAC specified for vessels participating in the Amendment 80 limited...

  5. 75 FR 69601 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Western Aleutian...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... Zone Off Alaska; Pacific Ocean Perch in the Western Aleutian District of the Bering Sea and Aleutian... for Pacific ocean perch in the Western Aleutian District of the Bering Sea and Aleutian Islands... necessary to prevent exceeding the 2010 allocation of Pacific ocean perch in this area allocated to vessels...

  6. 75 FR 69599 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch by Vessels in the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... Zone Off Alaska; Pacific Ocean Perch by Vessels in the Amendment 80 Limited Access Fishery in the...: Temporary rule; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch by vessels.... The 2010 Pacific ocean perch TAC specified for vessels participating in the Amendment 80 limited...

  7. 75 FR 69600 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Eastern Aleutian...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... Off Alaska; Pacific Ocean Perch in the Eastern Aleutian District of the Bering Sea and Aleutian... for Pacific ocean perch in the Eastern Aleutian District of the Bering Sea and Aleutian Islands... necessary to prevent exceeding the 2010 allocation of Pacific ocean perch in this area allocated to vessels...

  8. 75 FR 42338 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Western...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-21

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the Western Regulatory Area of the Gulf of Alaska AGENCY.... ACTION: Temporary rule; closure. SUMMARY: NMFS is prohibiting retention of Pacific ocean perch in the... allowable catch (TAC) of Pacific ocean perch in the Western Regulatory Area of the GOA has been reached...

  9. 77 FR 39649 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Western...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-05

    ... Zone Off Alaska; Pacific Ocean Perch in the Western Regulatory Area of the Gulf of Alaska AGENCY.... ACTION: Temporary rule; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch in... the 2012 total allowable catch (TAC) of Pacific ocean perch in the Western Regulatory Area of the GOA...

  10. 75 FR 53608 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the West Yakutat...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-01

    ... Zone Off Alaska; Pacific Ocean Perch in the West Yakutat District of the Gulf of Alaska AGENCY.... ACTION: Temporary rule; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch in... the 2010 total allowable catch (TAC) of Pacific ocean perch in the West Yakutat District of the GOA...

  11. 76 FR 39791 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Western...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-07

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the Western Regulatory Area of the Gulf of Alaska AGENCY.... ACTION: Temporary rule; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch in... the 2011 total allowable catch (TAC) of Pacific ocean perch in the Western Regulatory Area of the GOA...

  12. 77 FR 41332 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Western...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-13

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the Western Regulatory Area of the Gulf of Alaska AGENCY.... ACTION: Temporary rule; closure. SUMMARY: NMFS is prohibiting retention of Pacific ocean perch in the... allowable catch (TAC) of Pacific ocean perch in the Western Regulatory Area of the GOA has been reached...

  13. 76 FR 43933 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Western Aleutian...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-22

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the Western Aleutian District of the Bering Sea and... directed fishing for Pacific ocean perch in the Western Aleutian District of the Bering Sea and Aleutian... action is necessary to prevent exceeding the 2011 allocation of Pacific ocean perch in this area...

  14. 77 FR 42439 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the West Yakutat...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-19

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the West Yakutat District of the Gulf of Alaska AGENCY.... ACTION: Temporary rule; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch in... the 2012 total allowable catch (TAC) of Pacific ocean perch in the West Yakutat District of the GOA...

  15. 76 FR 45709 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the West Yakutat...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-01

    ... Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the West Yakutat District of the... for Pacific ocean perch in the West Yakutat District of the Gulf of Alaska (GOA). This action is necessary to prevent exceeding the 2011 total allowable catch (TAC) of Pacific ocean perch in the West...

  16. 75 FR 39183 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Western...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-08

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the Western Regulatory Area of the Gulf of Alaska AGENCY.... ACTION: Temporary rule; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch in... the 2010 total allowable catch (TAC) of Pacific ocean perch in the Western Regulatory Area of the GOA...

  17. 78 FR 42718 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-17

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea and Aleutian Islands Management Area AGENCY.... ACTION: Temporary rule; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch in... exceeding the 2013 total allowable catch (TAC) of Pacific ocean perch in this area allocated to...

  18. 76 FR 65972 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Eastern Aleutian...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-25

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the Eastern Aleutian District of the Bering Sea and... directed fishing for Pacific ocean perch in the Eastern Aleutian District of the Bering Sea and Aleutian... action is necessary to prevent exceeding the 2011 allocation of Pacific ocean perch in this...

  19. 77 FR 39440 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Central Aleutian...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-03

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the Central Aleutian District of the Bering Sea and... directed fishing for Pacific ocean perch in the Central Aleutian District of the Bering Sea and Aleutian... action is necessary to prevent exceeding the 2012 allocation of Pacific ocean perch in this...

  20. 77 FR 34262 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Western Aleutian...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-11

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the Western Aleutian District of the Bering Sea and... directed fishing for Pacific ocean perch in the Western Aleutian District of the Bering Sea and Aleutian... action is necessary to prevent exceeding the 2012 allocation of Pacific ocean perch in this...

  1. 76 FR 68658 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-07

    ... Zone Off Alaska; Pacific Ocean Perch in the Bering Sea Subarea of the Bering Sea and Aleutian Islands... is opening directed fishing for Pacific ocean perch in the Bering Sea subarea of the Bering Sea and... Pacific ocean perch specified for the Bering Sea subarea of the Bering Sea and Aleutian Islands...

  2. 76 FR 39793 - Fisheries of the Exclusive Economic Zone Off Alaska; Northern Rockfish, Pacific Ocean Perch, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-07

    ... Economic Zone Off Alaska; Northern Rockfish, Pacific Ocean Perch, and Pelagic Shelf Rockfish for Catcher... northern rockfish, Pacific ocean perch, and pelagic shelf rockfish for catcher vessels participating in the... necessary to prevent exceeding the 2011 total allowable catch (TAC) of northern rockfish, Pacific ocean...

  3. 75 FR 38938 - Fisheries of the Exclusive Economic Zone Off Alaska; Northern Rockfish, Pacific Ocean Perch, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-07

    ... Economic Zone Off Alaska; Northern Rockfish, Pacific Ocean Perch, and Pelagic Shelf Rockfish for Catcher... northern rockfish, Pacific ocean perch, and pelagic shelf rockfish for catcher vessels participating in the... necessary to prevent exceeding the 2010 total allowable catch (TAC) of northern rockfish, Pacific ocean...

  4. 75 FR 42337 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch for Catcher/Processors...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-21

    ... Economic Zone Off Alaska; Pacific Ocean Perch for Catcher/Processors Participating in the Rockfish Limited...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch by catcher/processors...). This action is necessary to prevent exceeding the 2010 total allowable catch (TAC) of Pacific ocean...

  5. 76 FR 43934 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch for Catcher/Processors...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-22

    ... Economic Zone Off Alaska; Pacific Ocean Perch for Catcher/Processors Participating in the Rockfish Limited...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch by catcher/processors...). This action is necessary to prevent exceeding the 2011 total allowable catch (TAC) of Pacific ocean...

  6. 77 FR 65838 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-31

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea Subarea of the Bering Sea and Aleutian... directed fishing for Pacific ocean perch in the Bering Sea subarea of the Bering Sea and Aleutian Islands management area. This action is necessary to fully use the 2012 total allowable catch of Pacific ocean...

  7. 75 FR 68726 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-09

    ... Zone Off Alaska; Pacific Ocean Perch in the Bering Sea Subarea of the Bering Sea and Aleutian Islands... directed fishing for Pacific ocean perch in the Bering Sea subarea of the Bering Sea and Aleutian Islands management area. This action is necessary to fully use the 2010 total allowable catch of Pacific ocean...

  8. 76 FR 40838 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-12

    ... Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels Participating in the Rockfish Entry Level... vessels participating in the rockfish entry level fishery in the Central Regulatory Area of the Gulf of... Pacific ocean perch for trawl catcher vessels participating in the rockfish entry level fishery in...

  9. 76 FR 46207 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-02

    ... Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels Participating in the Rockfish Entry Level... vessels participating in the rockfish entry level fishery in the Central Regulatory Area of the Gulf of... Pacific ocean perch for trawl catcher vessels participating in the rockfish entry level fishery in...

  10. 75 FR 53873 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch for Vessels...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-02

    ... Economic Zone Off Alaska; Pacific Ocean Perch for Vessels Participating in the Rockfish Entry Level Fishery... entry level fishery in the Central Regulatory Area of the Gulf of Alaska (GOA). This action is necessary... participating in the rockfish entry level fishery in the Central Regulatory Area of the GOA. DATES:...

  11. 75 FR 41999 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-20

    ... Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels Participating in the Rockfish Entry Level... vessels participating in the rockfish entry level fishery in the Central Regulatory Area of the Gulf of... perch for trawl catcher vessels participating in the rockfish entry level fishery in the...

  12. 75 FR 38936 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-07

    ... Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels Participating in the Rockfish Entry Level... participating in the rockfish entry level fishery in the Central Regulatory Area of the Gulf of Alaska (GOA... perch for trawl catcher vessels participating in the rockfish entry level fishery in the...

  13. 75 FR 43090 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Western Yakutat...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-23

    ... catcher/processors participating in the limited access or opt-out fisheries that are subject to sideboard... ocean perch established for catcher/ processors participating in the limited access or opt-out fisheries... established for catcher/processors participating in the limited access or opt-out fisheries that are...

  14. 75 FR 69361 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-12

    ... available data and finds that the ITAC for Pacific ocean perch in the Bering Sea subarea needs to be... fisheries data in a timely fashion and would delay the apportionment of the non-specified reserves of... plan for the fishing season, and to avoid potential disruption to the fishing fleet and...

  15. 76 FR 39790 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-07

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE... Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels Participating in the Rockfish Entry Level... participating in the rockfish entry level fishery in the Central Regulatory Area of the Gulf of Alaska (GOA...

  16. Genetic structure and different color morphotypes suggest the occurrence and bathymetric segregation of two incipient species of Sebastes off Argentina

    NASA Astrophysics Data System (ADS)

    Venerus, Leonardo A.; Ciancio, Javier E.; Riva-Rossi, Carla; Gilbert-Horvath, Elizabeth A.; Gosztonyi, Atila E.; Garza, John Carlos

    2013-07-01

    Rockfishes of the genus Sebastes are extensively distributed in the Pacific and Atlantic oceans. Although the occurrence of two morphologically similar species in the Southern Hemisphere, Sebastes oculatus and Sebastes capensis, is now clearly established, the taxonomic status and phylogeographic patterns for the genus in the region have not yet been completely resolved. In this study, we provide new insights into the taxonomy and evolutionary relationships of rockfishes inhabiting the Southwestern Atlantic Ocean, off the coast of mainland Argentina, by combining mitochondrial DNA (mtDNA) control region sequences, microsatellite data, and color pattern analyses. Differences in coloration ("dark" and "light" fish) together with bathymetric segregation between color morphotypes were evident from fish collection and literature review. In addition, the mtDNA phylogenetic analysis and Bayesian clustering analysis using microsatellite data separated the fish into two distinct groups ( F ST = 0.041), most likely representing incipient species. Our results suggest that speciation-by-depth in the absence of physical barriers could be a widespread mechanism of speciation in Sebastes from both the Northern and Southern Hemispheres. Nevertheless, the degree of genetic differentiation found, added to the large number of individuals displaying high levels of admixture, points to the occurrence of incomplete reproductive barriers between color morphotypes. Beyond the taxonomic and phylogeographic implications of our findings, the occurrence of distinct groups of Sebastes off the coast of Argentina being targeted by different fisheries (angling and trawling) has consequences for the design and implementation of appropriate fishery regulations to avoid overharvest of either group.

  17. Genomic characterization of sex-identification markers in Sebastes carnatus and Sebastes chrysomelas rockfishes.

    PubMed

    Fowler, Benjamin L S; Buonaccorsi, Vincent P

    2016-05-01

    Fish have evolved a variety of sex-determining (SD) systems including male heterogamy (XY), female heterogamy (ZW) and environmental SD. Little is known about SD mechanisms of Sebastes rockfishes, a highly speciose genus of importance to evolutionary and conservation biology. Here, we characterize the sex determination system in the sympatrically distributed sister species Sebastes chrysomelas and Sebastes carnatus. To identify sex-specific genotypic markers, double digest restriction site - associated DNA sequencing (ddRAD-seq) of genomic DNA from 40 sexed individuals of both species was performed. Loci were filtered for presence in all of the individuals of one sex, absence in the other sex and no heterozygosity. Of the 74 965 loci present in all males, 33 male-specific loci met the criteria in at least one species and 17 in both. Conversely, no female-specific loci were detected, together providing evidence of an XY sex determination system in both species. When aligned to a draft reference genome from Sebastes aleutianus, 26 sex-specific loci were interspersed among 1168 loci that were identical between sexes. The nascent Y chromosome averaged 5% divergence from the X chromosome and mapped to reference Sebastes genome scaffolds totalling 6.9Mbp in length. These scaffolds aligned to a single chromosome in three model fish genomes. Read coverage differences were also detected between sex-specific and autosomal loci. A PCR-RFLP assay validated the bioinformatic results and correctly identified sex of five additional individuals of known sex. A sex-determining gene in other teleosts gonadal soma-derived factor (gsdf) was present in the model fish chromosomes that spanned our sex-specific markers.

  18. Genetic structure and different color morphotypes suggest the occurrence and bathymetric segregation of two incipient species of Sebastes off Argentina.

    PubMed

    Venerus, Leonardo A; Ciancio, Javier E; Riva-Rossi, Carla; Gilbert-Horvath, Elizabeth A; Gosztonyi, Atila E; Garza, John Carlos

    2013-07-01

    Rockfishes of the genus Sebastes are extensively distributed in the Pacific and Atlantic oceans. Although the occurrence of two morphologically similar species in the Southern Hemisphere, Sebastes oculatus and Sebastes capensis, is now clearly established, the taxonomic status and phylogeographic patterns for the genus in the region have not yet been completely resolved. In this study, we provide new insights into the taxonomy and evolutionary relationships of rockfishes inhabiting the Southwestern Atlantic Ocean, off the coast of mainland Argentina, by combining mitochondrial DNA (mtDNA) control region sequences, microsatellite data, and color pattern analyses. Differences in coloration ("dark" and "light" fish) together with bathymetric segregation between color morphotypes were evident from fish collection and literature review. In addition, the mtDNA phylogenetic analysis and Bayesian clustering analysis using microsatellite data separated the fish into two distinct groups (F ST = 0.041), most likely representing incipient species. Our results suggest that speciation-by-depth in the absence of physical barriers could be a widespread mechanism of speciation in Sebastes from both the Northern and Southern Hemispheres. Nevertheless, the degree of genetic differentiation found, added to the large number of individuals displaying high levels of admixture, points to the occurrence of incomplete reproductive barriers between color morphotypes. Beyond the taxonomic and phylogeographic implications of our findings, the occurrence of distinct groups of Sebastes off the coast of Argentina being targeted by different fisheries (angling and trawling) has consequences for the design and implementation of appropriate fishery regulations to avoid overharvest of either group.

  19. Age validation of quillback rockfish (Sebastes maliger) using bomb radiocarbon

    SciTech Connect

    Kerr, L A; Andrews, A H; Munk, K; Coale, K H; Frantz, B R; Cailliet, G M; Brown, T A

    2005-01-05

    Rockfishes (Sebastes spp.) support one of the most economically important fisheries of the Pacific Northwest and it is essential for sustainable management that age estimation procedures be validated for these species. Atmospheric testing of thermonuclear devices during the 1950s and 1960s created a global radiocarbon ({sup 14}C) signal in the ocean environment that scientists have identified as a useful tracer and chronological marker in natural systems. In this study, we first demonstrated that fewer samples are necessary for age validation using the bomb-generated {sup 14}C signal by emphasizing the utility of the time-specific marker created by the initial rise of bomb-{sup 14}C. Second, the bomb-generated {sup 14}C signal retained in fish otoliths was used to validate the age and age estimation methodology of the quillback rockfish (Sebastes maliger) in the waters of southeast Alaska. Radiocarbon values from the first year's growth of quillback rockfish otoliths were plotted against estimated birth year producing a {sup 14}C time series spanning 1950 to 1985. The initial rise of bomb-{sup 14}C from pre-bomb levels ({approx} -90 {per_thousand}) occurred in 1959 {+-} 1 year and {sup 14}C levels rose relatively rapidly to peak {Delta}{sup 14}C values in 1967 (+105.4 {per_thousand}), with a subsequent declining trend through the end of the record in 1985 (+15.4 {per_thousand}). The agreement between the year of initial rise of {sup 14}C levels from the quillback rockfish record and the chronometer determined for the waters of southeast Alaska from yelloweye rockfish (S. ruberrimus) otoliths validated the ageing methodology for the quillback rockfish. The concordance of the entire quillback rockfish {sup 14}C record with the yelloweye rockfish time series demonstrated the effectiveness of this age validation technique, confirmed the longevity of the quillback rockfish up to a minimum of 43 years, and strongly supports higher age estimates of up to 90 years.

  20. Sea Perch Project

    NASA Image and Video Library

    2010-12-11

    David Lalejini, an employee of the Naval Research Laboratory at NASA's John C. Stennis Space Center, helps a pair of teachers deploy a remotely-operated underwater Sea Perch robot during workshop activities Dec. 11. The Stennis Education Office teamed with Naval Research Laboratory counterparts to conduct a two-day workshop Dec. 10-11 for Louisiana and Mississippi teachers. During the no-cost workshop, teachers learned to build and operate Sea Perch robots. The teachers now can take the Sea Perch Program back to students.

  1. The origin, evolution, and diversification of rockfishes of the genus Sebastes (Cuvier).

    PubMed

    Hyde, John R; Vetter, Russell D

    2007-08-01

    that Sebastes originated in the middle Miocene, concordant with fossil data, and began substantial diversification and dispersal in synchrony with high-latitude cooling and establishment of productive upwelling systems across the north Pacific (NP) in the late Miocene. Contrary to contemporary taxonomic criteria that often group Asian and North American species based on common morphology, the molecular phylogenies tend to indicate geographically circumscribed lineages with no evidence for repeated long distance dispersal between disjunct biogeographic provinces (e.g., Asian species nested within a North American lineage). No examples of large-scale glacial vicariance as would be suggested by Asian and North American sibling species were observed. To the contrary, sibling species tended to be in geographic proximity. While occasional long distance dispersal may occur, such as the single colonization of the SH, and thermal barriers presently exist between the NP, NA, GC, and SH taxa, the observable patterns in Sebastes suggest colonization occurs by stepwise invasion of newly available habitat when temperature conditions permit. Colonization events are spread throughout the sub-generic lineages. Vicariant isolation processes may occur on smaller geographic scales perhaps due to local isolating mechanisms such as glacial advance and retreat, sea level change, and ocean currents. Allopatric differences may be enhanced by a tendency for female mate choice and assortative mating in these livebearing species. The ongoing process of thermal advance and retreat is reflected in contemporary patterns of phylogeographic population genetic structure within species and may be enhanced under climate warming.

  2. Dynamics of a parasite assemblage of the Vermilion Rockfish Sebastes miniatus from northwestern Baja California, México

    NASA Astrophysics Data System (ADS)

    Rodríguez-Santiago, M. A.; Rosales-Casián, J. A.; Grano-Maldonado, M. I.

    2014-06-01

    A parasite assemblage of Sebastes miniatus from northwestern Baja California, México, was composed of a total of 12 species: five ectoparasites (two monogeneans and three parasitic copepods) and seven endoparasites (two digeneans, one cestode, three nematodes, and one acanthocephala). Five of these parasites constituted new genera records to the genus Sebastes, and nine were new geographic records. The most abundant species were the endoparasites Parabothriocephalus sagitticeps, Hysterothylacium sp., and Anisakis sp., and the specific richness ranged from 1 to 8 parasite species per host. The most important parasite species in terms of prevalence were Microcotyle sebastis (93 %) and Anisakis sp. (92 %). The mean abundance of parasites found in S. miniatus showed significant variations over the year, with maximum values (31.7 individuals/host) in August, and minimum (0.39 individuals/host) in February. P. sagitticeps showed the highest mean intensity of infection (190.4 parasites/host), followed by Anisakis sp. (127.2 parasites/host) and Hysterothylacium sp. (46.6 parasites/host). The presence of larval stages of the nematodes Anisakis, Pseudoterranova, and Hysterothylacium is particularly important due to their high abundance and prevalence and because they may represent a human health risk (anisakiasis). Rockfishes (family Scorpaenidae) of the genus Sebastes constitute one of the most important groundfish resources in the American and Mexican northern Pacific Ocean, both for recreational and for the commercial fisheries of California and Baja California. These rockfish species makes up a substantial part of the Mexican cuisine.

  3. Taxonomic review of the Sebastes pachycephalus complex (Scorpaeniformes: Scorpaenidae).

    PubMed

    Kai, Yoshiaki; Nakabo, Tetsuji

    2013-01-01

    A taxonomic review of the Sebastes pachycephalus complex established the existence of two valid species, S. pachycephalus and S. nudus. Similarities between them include: cranium armed dorsally with robust preocular, supraocular, postocular, and parietal spines; interorbital space concave; lower jaw lacking scales, shorter than upper jaw; thickened rays in ventral half of pectoral fin; dorsal fin usually with 13 spines and 12 soft-rays; pored lateral line scales 27-35 (usually 29-33). However, S. pachycephalus is distinguishable from the latter in having minute scales below the entire dorsal-fin spine base (vs. lacking minute scales below first to fifth or variously to the posteriormost spine in the latter), dark spots scattered on the dorsal, anal and caudal fins (vs. no distinct dark spots), and lacking distinct colored markings on the dorsum (vs. yellow or reddish-brown markings present). Although both species occur off the southern Korean Peninsula and in the Bohai and Yellow Seas, in Japanese waters, the former is distributed from northern Honshu Is. southward to southern Kyushu Is., whereas the latter extends from southern Hokkaido southward along the Pacific coast of Japan to Kanagawa, and along the Sea of Japan coast to northern Kyushu Is., including the Seto Inland Sea. Sebastes nigricaus, S. nigricans, and S. latus are confirmed as junior synonyms of S. pachycephalus, and S. chalcogrammus as junior synonym of S. nudus, based on the examination of type specimens.

  4. [Fauna of myxosporidians (Myxozoa: Myxosporea) in the scorpionfish genus sebastes from North Atlantic].

    PubMed

    Bakaĭ, Iu I; Grudnev, M A

    2009-01-01

    Data on species composition, hosts, localities, and occurrence of myxosporidean in four host species of the scorpionfish genus Sebastes from different areas of North Atlantic and Barents Sea are presented. Thirteen myxosporidean species are recorded.

  5. Variation in habitat use by juvenile Acadian redfish, Sebastes fasciatus

    USGS Publications Warehouse

    Auster, P.J.; Lindholm, J.; Valentine, P.C.

    2003-01-01

    A basic paradigm in behavioral ecology is that organisms expand their distribution as preferred sites become saturated with individuals that reduce the availability of resources (e.g., shelter, prey) on a per capita basis. Previous fish community studies at Stellwagen Bank National Marine Sanctuary have shown that juvenile Acadian redfish Sebastes fasciatus (20 cm TL) also occurred in dense cerianthid habitats. Two explanations for these distributions can be advanced. The simplest is that redfish use both boulder and cerianthid habitats on an encounter basis, regardless of habitat saturation or predation pressure. Alternatively, boulder reefs serve as recruitment habitats and cerianthid habitats serve as a conduit for redfish moving away from saturated boulder reef sites, essentially serving as elements of a 'redfish pump'.

  6. Perching behaviour and perch height preference of laying hens in furnished cages varying in height.

    PubMed

    Struelens, E; Tuyttens, F A M; Duchateau, L; Leroy, T; Cox, M; Vranken, E; Buyse, J; Zoons, J; Berckmans, D; Odberg, F; Sonck, B

    2008-07-01

    1. The objective was to investigate the effect of cage height on perch height preference and perching behaviour in laying hens. Twelve groups of two hens and 12 groups of 14 hens were tested in furnished cages equipped with two wooden perches. These stepwise perches were designed such that hens could choose between 7 different heights (6, 11, 16, 21, 26, 31 and 36 cm). Day- and night-time perching behaviour was observed on 4 consecutive days with a different cage height each day: 150, 55, 50 and 45 cm. 2. Given that a minimum perch-roof distance of 19 to 24 cm was available, hens preferred to roost on the highest perches at night. 3. Lowering cage height not only forced hens to use lower perches, but also reduced time spent on the perches during the day (two-hen and 14-hen test) and night (14-hen test). Moreover, it affected daytime behavioural activities (more standing and less preening) on the perches in the two-hen tests (but not in the 14-hen tests). 4. During the day lower perches were used more for standing and walking, higher perches more for sitting and sleeping. This behavioural differentiation was most pronounced in the highest cages. 5. Perch preference and perching behaviour depend on both the floor-perch distance and the perch-roof distance. Higher cages provide more opportunity for higher perches (which hens prefer), for better three-dimensional spacing (and consequently reduced density at floor level) and for behavioural differentiation according to perch height.

  7. Perching aerodynamics and trajectory optimization

    NASA Astrophysics Data System (ADS)

    Wickenheiser, Adam; Garcia, Ephrahim

    2007-04-01

    Advances in smart materials, actuators, and control architecture have enabled new flight capabilities for aircraft. Perching is one such capability, described as a vertical landing maneuver using in-flight shape reconfiguration in lieu of high thrust generation. A morphing, perching aircraft design is presented that is capable of post stall flight and very slow landing on a vertical platform. A comprehensive model of the aircraft's aerodynamics, with special regard to nonlinear affects such as flow separation and dynamic stall, is discussed. Trajectory optimization using nonlinear programming techniques is employed to show the effects that morphing and nonlinear aerodynamics have on the maneuver. These effects are shown to decrease the initial height and distance required to initiate the maneuver, reduce the bounds on the trajectory, and decrease the required thrust for the maneuver. Perching trajectories comparing morphing versus fixed-configuration and stalled versus un-stalled aircraft are presented. It is demonstrated that a vertical landing is possible in the absence of high thrust if post-stall flight capabilities and vehicle reconfiguration are utilized.

  8. A microsatellite genetic linkage map of black rockfish ( Sebastes schlegeli)

    NASA Astrophysics Data System (ADS)

    Chu, Guannan; Jiang, Liming; He, Yan; Yu, Haiyang; Wang, Zhigang; Jiang, Haibin; Zhang, Quanqi

    2014-12-01

    Ovoviviparous black rockfish ( Sebastes schlegeli) is an important marine fish species for aquaculture and fisheries in China. Genetic information of this species is scarce because of the lack of microsatellite markers. In this study, a large number of microsatellite markers of black rockfish were isolated by constructing microsatellite-enriched libraries. Female- and male-specific genetic linkage maps were constructed using 435 microsatellite markers genotyped in a full-sib family of the fish species. The female linkage map contained 140 microsatellite markers, in which 23 linkage groups had a total genetic length of 1334.1 cM and average inter-marker space of 13.3 cM. The male linkage map contained 156 microsatellite markers, in which 25 linkage groups had a total genetic length of 1359.6 cM and average inter-marker distance of 12.4 cM. The genome coverage of the female and male linkage maps was 68.6% and 69.3%, respectively. The female-to-male ratio of the recombination rate was approximately 1.07:1 in adjacent microsatellite markers. This paper presents the first genetic linkage map of microsatellites in black rockfish. The collection of polymorphic markers and sex-specific linkage maps of black rockfish could be useful for further investigations on parental assignment, population genetics, quantitative trait loci mapping, and marker-assisted selection in related breeding programs.

  9. Influence of perched groundwater on base flow

    USGS Publications Warehouse

    Niswonger, R.G.; Fogg, G.E.

    2008-01-01

    Analysis with a three-dimensional variably saturated groundwater flow model provides a basic understanding of the interplay between streams and perched groundwater. A simplified, layered model of heterogeneity was used to explore these relationships. Base flow contribution from perched groundwater was evaluated with regard to varying hydrogeologic conditions, including the size and location of the fine-sediment unit and the hydraulic conductivity of the fine-sediment unit and surrounding coarser sediment. Simulated base flow was sustained by perched groundwater with a maximum monthly discharge in excess of 15 L/s (0.6 feet3/s) over the length of the 2000-m stream reach. Generally, the rate of perched-groundwater discharge to the stream was proportional to the hydraulic conductivity of sediment surrounding the stream, whereas the duration of discharge was proportional to the hydraulic conductivity of the fine-sediment unit. Other aspects of the perched aquifer affected base flow, such as the depth of stream penetration and the size of the fine-sediment unit. Greater stream penetration decreased the maximum base flow contribution but increased the duration of contribution. Perched groundwater provided water for riparian vegetation at the demand rate but reduced the duration of perched-groundwater discharge nearly 75%. Copyright 2008 by the American Geophysical Union.

  10. Age validation of canary rockfish (Sebastes pinniger) using two independent otolith techniques: lead-radium and bomb radiocarbon dating.

    SciTech Connect

    Andrews, A H; Kerr, L A; Cailliet, G M; Brown, T A; Lundstrom, C C; Stanley, R D

    2007-11-04

    Canary rockfish (Sebastes pinniger) have long been an important part of recreational and commercial rockfish fishing from southeast Alaska to southern California, but localized stock abundances have declined considerably. Based on age estimates from otoliths and other structures, lifespan estimates vary from about 20 years to over 80 years. For the purpose of monitoring stocks, age composition is routinely estimated by counting growth zones in otoliths; however, age estimation procedures and lifespan estimates remain largely unvalidated. Typical age validation techniques have limited application for canary rockfish because they are deep dwelling and may be long lived. In this study, the unaged otolith of the pair from fish aged at the Department of Fisheries and Oceans Canada was used in one of two age validation techniques: (1) lead-radium dating and (2) bomb radiocarbon ({sup 14}C) dating. Age estimate accuracy and the validity of age estimation procedures were validated based on the results from each technique. Lead-radium dating proved successful in determining a minimum estimate of lifespan was 53 years and provided support for age estimation procedures up to about 50-60 years. These findings were further supported by {Delta}{sup 14}C data, which indicated a minimum estimate of lifespan was 44 {+-} 3 years. Both techniques validate, to differing degrees, age estimation procedures and provide support for inferring that canary rockfish can live more than 80 years.

  11. A new record of Sebastes koreanus from China based on morphological characters and DNA barcoding

    NASA Astrophysics Data System (ADS)

    Fang, Yalu; Kai, Yoshiaki; Yanagimoto, Takashi; Song, Na; Gao, Tianxiang

    2015-05-01

    A new record of Sebastes koreanus (Kim and Lee, 1994) was documented based on morphological characters and DNA barcoding. Fifty-six Sebastes specimens were collected from the coastal waters of northern China. Samples were identified as S. koreanus based on morphological characters. The coloration and morphometric measurements were consistent with those described from specimens collected in South Korea. In this study, specimens had the following morphological characteristics: light brown body with dark stripes and tiny dark spots, 4-5 wide indistinct vertical patterns on the side, 2 radial stripes behind and below the eyes, 1 large dark blotch on the opercle. Additionally, the following meristic characters were recorded: dorsal fin XIV-13, pectoral fin 16, anal fin III-6-7, pelvic fin I-5, lateral line scales 29-30, and vertebrae 26. The fragment of cytochrome oxidase subunit I ( COI) gene of mitochondrial DNA was sequenced for phylogenetic analysis. The mean genetic distance within the species was 0.3%. Net genetic distances between S. koreanus and other Sebastes species ranged from 3.1% to 7.6%, which was greater than the threshold for species delimitation. The phylogenetic analysis strongly supports the validity of S. koreanus in China at the genetic level. The origion, evolution, patterns of speciation and unique features in genome divergence among primate lineages of this species still need future directions of research.

  12. Subtle Population Genetic Structure in Yelloweye Rockfish (Sebastes ruberrimus) Is Consistent with a Major Oceanographic Division in British Columbia, Canada

    PubMed Central

    Siegle, Matthew R.; Taylor, Eric B.; Miller, Kristi M.; Withler, Ruth E.; Yamanaka, K. Lynne

    2013-01-01

    The boundaries between oceanographic domains often function as dispersal barriers for many temperate marine species with a dispersive pelagic larval phase. Yelloweye rockfish (Sebastes ruberrimus, YR) are widely distributed across the northeastern Pacific Ocean, inhabiting coastal rocky reefs from the Aleutian Islands in Alaska through southern California. This species exhibits an extended pelagic larval duration and has the capacity for long distance larval transport. We assayed 2,862 YR individuals from 13 general areas in the northeast Pacific Ocean for allelic variation at nine microsatellite loci. Bayesian model-based clustering analyses grouped individuals from the Strait of Georgia (SG) into a distinct genetic cluster, while individuals from outer coastal water locations (OCLs) were partitioned equally across two genetic clusters, including the cluster associated with the SG fish. Pairwise FST values were consistently an order of magnitude higher for comparisons between the SG and OCLs than they were for all OCL-OCL comparisons (∼0.016 vs. ∼0.001). This same pattern was observed across two time points when individuals were binned into an “old” and “young” group according to birth year (old: ∼0.020 vs. 0.0003; young: ∼0.020 vs. ∼0.004). Additionally, mean allelic richness was markedly lower within the SG compared to the OCLs (8.00 vs. 10.54–11.77). These results indicate that the Strait of Georgia “deep-basin” estuary oceanographic domain acts as a dispersal barrier from the outer coastal waters via the Juan de Fuca Strait. Alternatively, selection against maladapted dispersers across this oceanographic transition may underlie the observed genetic differentiation between the Georgia basin and the outer coastal waters, and further work is needed to confirm the SG-OCL divide acts as a barrier to larval dispersal. PMID:23990926

  13. The effect of predation on stunted and nonstunted white perch

    USGS Publications Warehouse

    Gosch, N.J.C.; Pierce, L.L.; Pope, K.L.

    2010-01-01

    Predation is widely regarded as a means to prevent or minimise the establishment of a stunted (high density of slow growing individuals) population. We investigated the effect of predation on two different white perch Morone americana populations (stunted and nonstunted) by examining the stomach contents of piscivorous fishes. White perch and gizzard shad dominated piscivore diets in Branched Oak Lake, whereas white perch dominated piscivore diets in Pawnee Lake. White perch consumed in the stunted population (Branched Oak Lake) were larger and older than white perch consumed in the nonstunted population (Pawnee Lake). Many of the consumed white perch in the stunted population were sexually mature and had the opportunity to spawn at least once. In contrast, all of the consumed white perch in the nonstunted population were sexually immature. Predation may have reinforced the stunting of white perch in Branched Oak Lake through removal of the largest, oldest individuals. ?? 2010 John Wiley & Sons A/S.

  14. Habitat Suitability Index Models: Yellow perch

    USGS Publications Warehouse

    Krieger, Douglas A.; Terrell, James W.; Nelson, Patrick C.

    1983-01-01

    A review and synthesis of existing information were used to develop riverine and lacustrine habitat models for yellow perch (Perca flavescens). The models are scaled to produce an index of habitat suitability between 0 (unsuitable habitat) to 1 (optimally suitable habitat) for riverine, lacustrine, and palustrine habitat in the 48 contiguous United States. Habitat Suitability Indexes (HSI's) are designed for use with the Habitat Evaluation Procedures developed by the U.S. Fish and Wildlife Service. Also included are discussions of Suitability Index (SI) curves as used in the Instream Flow Incremental Methodology (IFIM) and SI curves available for an IFIM analysis of yellow perch habitat.

  15. Nile perch: the great lake experiment.

    PubMed

    Ogutu-ohwayo, R

    1998-01-01

    In order to improve the fishery of Lake Victoria, a large predatory fish, the Nile perch (Lates niloticus), was introduced into the lake to feed on the smaller but abundant haplochromines, thereby producing a larger fish for food consumption. Originally the lake had a very high fish species diversity, dominated by more than 300 species of haplochromine cichlids; however, they were too small to be exploited for food. It took about 20 years for the population of the Nile perch in the lake to increase significantly. Although increased fish production has benefited riparian communities by providing revenue, employment, and food, the introduction of the Nile perch has also resulted in extinction and has transformed the lake ecosystem. In response to the concern caused by the introduction of the Nile perch, the deteriorating water quality, and the need to sustain the lucrative fishery, the governments of Uganda, Kenya, and Tanzania have initiated the multisectoral Lake Victoria Environment Management Programme. Its goals are to control the loading of nutrients and contaminants into the lake, manage land use in the catchment area, manage the introduced fish species, conserve biodiversity, and control the spread of water hyacinths.

  16. Radiocarbon in otoliths of yelloweye rockfish (Sebastes ruberrimus): a reference time series for the coastal waters of southeast Alaska

    SciTech Connect

    Kerr-Ferrey, L A; Andrews, A H; Frantz, B R; Coale, K H; Brown, T A; Cailliet, G M

    2003-10-14

    Atmospheric testing of thermonuclear devices during the 1950s and 1960s created a global radiocarbon ({sup 14}C) signal in the environment that has provided a useful tracer and chronological marker in oceanic systems and organisms. The bomb-generated {sup 14}C signal retained in fish otoliths can be used as a permanent, time-specific recorder of the 14C present in ambient seawater, making it a useful tool in age validation of fishes. The goal of this study was to determine {sup 14}C levels in otoliths of the age-validated yelloweye rockfish (Sebastes ruberrimus) to establish a reference time series for the coastal waters of southeast Alaska. Radiocarbon values from the first year's growth of 43 yelloweye rockfish otoliths were plotted against estimated birth year to produce a 14C time series for these waters spanning 1940 to 1990. The time series shows the initial rise of bomb 14C occurred in 1958 in coastal southeast Alaskan waters and {sup 14}C levels rose relatively rapidly to peak {Delta}{sup 14}C values (60-70%) between 1966 and 1971, with a subsequent declining trend through the end of the record in 1990 (-3.2%). In addition, the radiocarbon data, independent of the radiometric study, confirms the longevity of the yelloweye rockfish up to a minimum of 44 years and strongly supports higher age estimates. The yelloweye rockfish record provides a {sup 14}C chronology that will be useful for the interpretation of {sup 14}C accreted in biological samples from these waters and in future rockfish age validation studies.

  17. Movements of blue rockfish (Sebastes mystinus) off central California with comparisons to similar species.

    PubMed

    Green, Kristen M; Greenley, Ashley P; Starr, Richard M

    2014-01-01

    Olive (Sebastes serranoides), black (Sebastes melanops), and blue rockfish (Sebastes mystinus) are all common inhabitants of nearshore ecosystems on the West coast of North America and important components of the recreational fishery off California. Acoustic monitoring studies indicate that olive rockfish are highly residential and that black rockfish are capable of long migrations and have less site fidelity; yet little is known about the long-term movements of blue rockfish. External tag-recapture studies indicate that blue rockfish may have intermediate movements relative to these congener nearshore species. To better understand the site fidelity, and daily and seasonal movements of blue rockfish over long (>1-year) time scales, we placed acoustic transmitters into 21 adult blue rockfish (30-41 cm total length) in Carmel Bay, California. Blue rockfish displayed intermediate movement patterns and residency relative to other similar kelp forest rockfish species. Two-thirds of tagged blue rockfish (13 fish) exhibited high residency to the study area (>12 mo). When in residence, mean home range of blue rockfish was 0.23 km2, however as many as 30% of tagged blue rockfish shifted their core home range area during the study. Most shifts in home range occurred during upwelling season, and tagged fish moved up to 3.1 km when in residence. Blue rockfish with short residence times were last detected in the study area in late winter and early spring. Blue rockfish were observed at shallower depths during day than night, likely indicative of diurnal feeding. However, over longer time scales, blue rockfish were detected at deeper depths during upwelling periods and with increased wave heights. Daily and seasonal vertical movements of blue rockfish may be influenced by upwelling conditions and local prey abundance.

  18. Movements of Blue Rockfish (Sebastes mystinus) off Central California with Comparisons to Similar Species

    PubMed Central

    Green, Kristen M.; Greenley, Ashley P.; Starr, Richard M.

    2014-01-01

    Olive (Sebastes serranoides), black (Sebastes melanops), and blue rockfish (Sebastes mystinus) are all common inhabitants of nearshore ecosystems on the West coast of North America and important components of the recreational fishery off California. Acoustic monitoring studies indicate that olive rockfish are highly residential and that black rockfish are capable of long migrations and have less site fidelity; yet little is known about the long-term movements of blue rockfish. External tag-recapture studies indicate that blue rockfish may have intermediate movements relative to these congener nearshore species. To better understand the site fidelity, and daily and seasonal movements of blue rockfish over long (>1-year) time scales, we placed acoustic transmitters into 21 adult blue rockfish (30–41 cm total length) in Carmel Bay, California. Blue rockfish displayed intermediate movement patterns and residency relative to other similar kelp forest rockfish species. Two-thirds of tagged blue rockfish (13 fish) exhibited high residency to the study area (>12 mo). When in residence, mean home range of blue rockfish was 0.23 km2, however as many as 30% of tagged blue rockfish shifted their core home range area during the study. Most shifts in home range occurred during upwelling season, and tagged fish moved up to 3.1 km when in residence. Blue rockfish with short residence times were last detected in the study area in late winter and early spring. Blue rockfish were observed at shallower depths during day than night, likely indicative of diurnal feeding. However, over longer time scales, blue rockfish were detected at deeper depths during upwelling periods and with increased wave heights. Daily and seasonal vertical movements of blue rockfish may be influenced by upwelling conditions and local prey abundance. PMID:24902049

  19. Volatile Compounds Produced in Sterile Fish Muscle (Sebastes melanops) by Pseudomonas perolens1

    PubMed Central

    Miller, A.; Scanlan, R. A.; Lee, J. S.; Libbey, L. M.; Morgan, M. E.

    1973-01-01

    Volatile compounds produced by Pseudomonas perolens ATCC 10757 in sterile fish muscle (Sebastes melanops) were identified by combined gas-liquid chromatography and mass spectrometry. Compounds positively identified included methyl mercaptan, dimethyl disulfide, dimethyl trisulfide, 3-methyl-1-butanol, butanone, and 2-methoxy-3-isopropylpyrazine. Compounds tentatively identified included 1-penten-3-ol and 2-methoxy-3-sec-butylpyrazine. The substituted pyrazine derivative 2-methoxy-3-isopropylpyrazine was primarily responsible for the musty, potato-like odor produced by P. perolens. PMID:4694344

  20. The geography of morphological convergence in the radiations of Pacific Sebastes rockfishes.

    PubMed

    Ingram, Travis; Kai, Yoshiaki

    2014-11-01

    The evolution of convergent phenotypes in lineages subject to similar selective pressures is a common feature of adaptive radiation. In geographically replicated radiations, repeated convergence occurs between clades occupying distinct regions or islands. Alternatively, a clade may repeatedly reach the same adaptive peaks in broadscale sympatry, resulting in extensive convergence within a region. Rockfish (Sebastes sp.) have radiated in both the northeast and northwest Pacific, allowing tests of the extent and geographic pattern of convergence in a marine environment. We used a suite of phylogenetically informed methods to test for morphological convergence in rockfish. We examined patterns of faunal similarity using nearest neighbor distances in morphospace and the frequency of morphologically similar yet distantly related species pairs. The extent of convergence both between regions and within the northeast Pacific exceeds the expectation under a Brownian motion null model, although constraints on trait space could account for the similarity. We then used a recently developed method (SURFACE) to identify adaptive peak shifts in Sebastes evolutionary history. We found that the majority of convergent peak shifts occur within the northeast Pacific rather than between regions and that the signal of peak shifts is strongest for traits related to trophic morphology. Pacific rockfish thus demonstrate a tendency toward morphological convergence within one of the two broad geographic regions in which they have diversified.

  1. Longitudinal dynamics of a perching aircraft concept

    NASA Astrophysics Data System (ADS)

    Wickenheiser, Adam; Garcia, Ephrahim; Waszak, Martin

    2005-05-01

    This paper introduces a morphing aircraft concept whose purpose is to demonstrate a new bio-inspired flight capability: perching. Perching is a maneuver that utilizes primarily aerodynamics -- as opposed to thrust generation -- to achieve a vertical or short landing. The flight vehicle that will accomplish this is described herein with particular emphasis on its addition levels of actuation beyond the traditional aircraft control surfaces. A computer model of the aircraft is developed in order to predict the changes in applied aerodynamic loads as it morphs and transitions through different flight regimes. The analysis of this model is outlined, including a lifting-line-based analytical technique and a trim and stability analysis. These analytical methods -- compared to panel or computational fluid dynamics (CFD) methods -- are considered desirable for the analysis of a large number of vehicle configurations and flight conditions. The longitudinal dynamics of this aircraft are studied, and several interesting results are presented. Of special interest are the changes in vehicle dynamics as the aircraft morphs from a cruise configuration to initiate the perching maneuver. Changes in trim conditions and stability are examined as functions of vehicle geometry. The time response to changes in vehicle configuration is also presented.

  2. Perch use by laying hens in a commercial aviary1

    PubMed Central

    Campbell, D. L. M.; Makagon, M. M.; Swanson, J. C.; Siegford, J. M.

    2016-01-01

    Non-cage housing systems, such as the aviary, are being implemented by the laying hen industry, including in North America, in an attempt to improve the welfare of hens. Perches are a resource that is consistently included in aviaries. Hens are strongly motivated to perch, and perching can improve leg bone strength. However, hens may prefer elevated perches, particularly at night, and thus simply providing perches is not enough to improve welfare; they must be provided in a way that allows all hens to access them. Observations of laying hens using perches and ledges (flat, solid metal shelves to assist hens’ movement between tiers) in a commercial aviary revealed variation in where hens roosted within the tiered aviary enclosure across the flock cycle (peak, mid and end of lay; P < 0.001 for all age points). Hens most often preferred roosting in the highest enclosure levels, leading to crowding on upper perches and ledges while perch space remained available on lower levels. Restricted access to preferable perches may cause frustration in hens, leading to welfare issues. Hens roosted more on perches at peak lay than mid and end lay (P < 0.001) but roosted less on ledges at peak lay than mid and end lay (P < 0.001). Additionally, more hens roosted on both perches and ledges in the ‘dark’ observation period compared with the number of hens roosting during the ‘light’ observation period (P < 0.001). Further research should look at all structural elements within the system that are used by hens for roosting, such as edges of tiers and upper wire floors, to evaluate how changes in perching preferences across the lay cycle may correlate with system design and bird-based parameters. PMID:26994206

  3. The role of vision in perching and grasping for MAVs

    NASA Astrophysics Data System (ADS)

    Thomas, Justin; Loianno, Giuseppe; Daniilidis, Kostas; Kumar, Vijay

    2016-05-01

    In this work, we provide an overview of vision-based control for perching and grasping for Micro Aerial Vehicles. We investigate perching on at, inclined, or vertical surfaces as well as visual servoing techniques for quadrotors to enable autonomous perching by hanging from cylindrical structures using only a monocular camera and an appropriate gripper. The challenges of visual servoing are discussed, and we focus on the problems of relative pose estimation, control, and trajectory planning for maneuvering a robot with respect to an object of interest. Finally, we discuss future challenges to achieve fully autonomous perching and grasping in more realistic scenarios.

  4. Field Verification of Stable Perched Groundwater in Layered Bedrock Uplands

    USGS Publications Warehouse

    Carter, J.T.; Gotkowitz, M.B.; Anderson, M.P.

    2011-01-01

    Data substantiating perched conditions in layered bedrock uplands are rare and have not been widely reported. Field observations in layered sedimentary bedrock in southwestern Wisconsin, USA, provide evidence of a stable, laterally extensive perched aquifer. Data from a densely instrumented field site show a perched aquifer in shallow dolomite, underlain by a shale-and-dolomite aquitard approximately 25 m thick, which is in turn underlain by sandstone containing a 30-m-thick unsaturated zone above a regional aquifer. Heads in water supply wells indicate that perched conditions extend at least several kilometers into hillsides, which is consistent with published modeling studies. Observations of unsaturated conditions in the sandstone over a 4-year period, historical development of the perched aquifer, and perennial flow from upland springs emanating from the shallow dolomite suggest that perched groundwater is a stable hydrogeologic feature under current climate conditions. Water-table hydrographs exhibit apparent differences in the amount and timing of recharge to the perched and regional flow systems; steep hydraulic gradients and tritium and chloride concentrations suggest there is limited hydraulic connection between the two. Recognition and characterization of perched flow systems have practical importance because their groundwater flow and transport pathways may differ significantly from those in underlying flow systems. Construction of multi-aquifer wells and groundwater withdrawal in perched systems can further alter such pathways. ?? 2010 The Author(s). Journal compilation ?? 2010 National Ground Water Association.

  5. Field verification of stable perched groundwater in layered bedrock uplands.

    PubMed

    Carter, Jonathon T V; Gotkowitz, Madeline B; Anderson, Mary P

    2011-01-01

    Data substantiating perched conditions in layered bedrock uplands are rare and have not been widely reported. Field observations in layered sedimentary bedrock in southwestern Wisconsin, USA, provide evidence of a stable, laterally extensive perched aquifer. Data from a densely instrumented field site show a perched aquifer in shallow dolomite, underlain by a shale-and-dolomite aquitard approximately 25 m thick, which is in turn underlain by sandstone containing a 30-m-thick unsaturated zone above a regional aquifer. Heads in water supply wells indicate that perched conditions extend at least several kilometers into hillsides, which is consistent with published modeling studies. Observations of unsaturated conditions in the sandstone over a 4-year period, historical development of the perched aquifer, and perennial flow from upland springs emanating from the shallow dolomite suggest that perched groundwater is a stable hydrogeologic feature under current climate conditions. Water-table hydrographs exhibit apparent differences in the amount and timing of recharge to the perched and regional flow systems; steep hydraulic gradients and tritium and chloride concentrations suggest there is limited hydraulic connection between the two. Recognition and characterization of perched flow systems have practical importance because their groundwater flow and transport pathways may differ significantly from those in underlying flow systems. Construction of multi-aquifer wells and groundwater withdrawal in perched systems can further alter such pathways.

  6. Controller design for a morphing, perching aircraft

    NASA Astrophysics Data System (ADS)

    Hurst, Allen; Garcia, Ephrahim

    2011-03-01

    This article compares two feedback compensator strategies for the task of guiding a morphing aircraft along a perching trajectory. The aircraft model includes novel, actuated degrees of freedom that allow for bulk movement of some airframe structures. This morphing ability allows the aircraft to perform maneuvers in a manner similar to some birds. The control methods compared in this article are a multi-stage compensator and a linear quadratic regulator. Simulations test the effectiveness of the compensators for initial state error and a trajectory disturbance. In these simulations the linear quadratic regulator outperforms the multi-stage compensator by repeatedly producing smaller state errors and by having lower error standard deviations.

  7. The complete mitochondrial genome of Sebastes pachycephalus (Scorpaenidae, Scorpaeniformes) from the East Sea, Korea.

    PubMed

    Jang, Yo-Soon; Park, Kwang-Jae; Kim, Ki-Yong; Kim, Sung

    2016-01-01

    Due to variations in coloration as well as other morphological features, the identification of Sebastes pachycephalus has been problematic. The complete mitogenome of S. pachycephalus was acquired using next-generation sequencing. The full genome was 16,415 base pairs (bp) in length, assembling two rRNAs, 22 tRNAs, one control region and 13 protein-coding genes (PCGs). The genome constitutes 27.9% A, 26.3% T, 17.2% G and 28.5% C, showing a slight AT bias (54.2%). All PCGs start with an ATG initial codon except COX1, which contains GTG. Most PCG stop codons were TAA, except for ND1 and ND3 (TAG) and Cytb (incomplete termination codon, T). All tRNAs showed the typical cloverleaf structure, except tRNA(Ser(AGY)), which lacks the DHU arm. The complete mitogenome of S. pachycephalus will help further identification and speciation analyses.

  8. The complete mitochondrial genome of the oblong rockfish Sebastes oblongus (Scorpaenidae, Scorpaeniformes).

    PubMed

    Jang, Yo-Soon; Oh, Sung-Yong; Park, Kwang-Jae; Kim, Ki-Yong; Kim, Sung

    2016-01-01

    The complete mitogenome of the oblong rockfish Sebastes oblongus was constructed using next-generation sequencing. The full genome was 16,396 bp in length, including two rRNA, 22 tRNA, one control region and 13 protein-coding genes (PCGs). The genome consisted of 28.0% A, 26.4% T, 16.9% G and 28.6% C, showing a slight AT bias (54.4%). All PCGs contained an ATG start codon, excluding COX1 that contained a GTG. All PCGs contained the stop codon TAA, excluding ND3 (TAG stop codon) and Cytb (incomplete termination codon, T). All tRNAs contained the typical clover leaf structure, except for two tRNAs, serine (AGY) and threonine, which lacked the DHU arm. The complete mitogenome of S. oblongus will contribute to genetic analysis of the effective population size for aquaculture.

  9. Histopathological observation of lymphocystis disease and lymphocystis disease virus (LCDV) detection in cultured diseased Sebastes schlegeli

    NASA Astrophysics Data System (ADS)

    Sheng, Xiuzhen; Zhan, Wenbin; Xu, Songjuan; Cheng, Shunfeng

    2007-10-01

    Lymphocystis nodules occurring in the cultured sting fish Sebastes schlegeli were observed under light and electron microscope. Lymphocystis disease virus (LCDV) in the tissues of diseased fish was detected with indirect immunofluorescence test (IFAT). Results showed that lymphocystis cells had overly irregular nuclei, basophilic intracytoplasmic inclusion bodies with virions budding from the surface, and hyaline capsules outside the cell membrane. Numerous virus particles about 200 nm in diameter scattered in the cytoplasm, electron-dense particles 70 80 nm in diameter filled in perinuclear cisterna, and membrane-enveloped particles with electron-dense core of 70 80 nm appeared around cellular nucleus. IFAT using monoclonal antibody against LCDV from Paralichthys olivaceus revealed that specific green fluorescence was present in the cytoplasm of lymphocystis cells, epithelium of stomach, gill lamellae, and muscular fibers under epidermis of S. schlegeli, just as that in the cytoplasm of lymphocystis cells of P. olivaceus, suggesting the presence of LCDV in these tissues.

  10. Effects of dietary chromium exposure to rockfish, Sebastes schlegelii are ameliorated by ascorbic acid.

    PubMed

    Kim, Jun-Hwan; Kang, Ju-Chan

    2017-05-01

    Juvenile rockfish Sebastes schlegelii (mean length 10.8±1.4cm, and mean weight 31.7±3.6g) were exposed for 4 weeks with the different levels of dietary chromium (Cr(6+)) at 0, 120 and 240mg/L and ascorbic acids (AsA) at 100, 200 and 400mg/L. Significant accumulation occurred in specific tissues and hematological parameters were altered: red blood cell count, hematocrit, and hemoglobin increased; plasma components were altered including calcium, glucose, cholesterol, total protein, glutamic oxalate transaminase, and glutamic pyruvate transaminase. However, magnesium and alkaline phosphatase concentrations were unchanged. Ascorbic acids reduced both chromium uptake into tissues and altered hematological parameters. Copyright © 2017. Published by Elsevier Inc.

  11. New technology turns wastes into revenue at Indiana perch farm

    USDA-ARS?s Scientific Manuscript database

    Bell Aquaculture is vertically integrated and has closed the perch lifecycle within environmentally friendly land-based closed-containment systems. This means that Bell Aquaculture controls the broodstock, spawning, fry culture, grow-out, and 52 week per year harvest of the perch, plus the fish proc...

  12. Total recoil: perch compliance alters jumping performance and kinematics in green anole lizards (Anolis carolinensis).

    PubMed

    Gilman, Casey A; Bartlett, Michael D; Gillis, Gary B; Irschick, Duncan J

    2012-01-15

    Jumping is a common form of locomotion for many arboreal animals. Many species of the arboreal lizard genus Anolis occupy habitats in which they must jump to and from unsteady perches, e.g. narrow branches, vines, grass and leaves. Anoles therefore often use compliant perches that could alter jump performance. In this study we conducted a small survey of the compliance of perches used by the arboreal green anole Anolis carolinensis in the wild (N=54 perches) and then, using perches within the range of compliances used by this species, investigated how perch compliance (flexibility) affects the key jumping variables jump distance, takeoff duration, takeoff angle, takeoff speed and landing angle in A. carolinensis in the laboratory (N=11). We observed that lizards lost contact with compliant horizontal perches prior to perch recoil, and increased perch compliance resulted in decreased jump distance and takeoff speed, likely because of the loss of kinetic energy to the flexion of the perch. However, the most striking effect of perch compliance was an unexpected one; perch recoil following takeoff resulted in the lizards being struck on the tail by the perch, even on the narrowest perches. This interaction between the perch and the tail significantly altered body positioning during flight and landing. These results suggest that although the use of compliant perches in the wild is common for this species, jumping from these perches is potentially costly and may affect survival and behavior, particularly in the largest individuals.

  13. A kingfisher perches on a branch

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A belted kingfisher perches on a twig in the Merritt Island National Wildlife Refuge, which shares a boundary with the Kennedy Space Center. The pigeon-sized, blue-gray male is identified by the blue-gray breast band; females show a chestnut belly band. The belted kingfisher ranges throughout the United States and Canada, wintering south to Panama and the West Indies. They dive into the water for fish and may also take crabs, crayfish, salamanders, lizards, mice and insects. The 92,000-acre refuge is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles. The marshes and open water of the refuge also provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds.

  14. A kingfisher perches on a branch

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A belted kingfisher perches on a twig in the Merritt Island National Wildlife Refuge, which shares a boundary with the Kennedy Space Center. The pigeon-sized, blue-gray male is identified by the blue-gray breast band; females show a chestnut belly band. The belted kingfisher ranges throughout the United States and Canada, wintering south to Panama and the West Indies. They dive into the water for fish and may also take crabs, crayfish, salamanders, lizards, mice and insects. The 92,000-acre refuge is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles. The marshes and open water of the refuge also provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds.

  15. Experimental analysis of perching in the European starling (Sturnus vulgaris: Passeriformes; Passeres), and the automatic perching mechanism of birds.

    PubMed

    Galton, Peter M; Shepherd, Jeffrey D

    2012-04-01

    The avian automatic perching mechanism (APM) involves the automatic digital flexor mechanism (ADFM) and the digital tendon-locking mechanism (DTLM). When birds squat on a perch to sleep, the increased tendon travel distance due to flexion of the knee and ankle supposedly causes the toes to grip the perch (ADFM) and engage the DTLM so perching while sleeping involves no muscular effort. However, the knees and ankles of sleeping European starlings (Sturnus vulgaris) are only slightly flexed and, except for occasional balancing adjustments, the distal two-thirds of the toes are not flexed to grip a 6-mm-diameter perch. The cranial ankle angle (CAA) is ∼120° and the foot forms an inverted "U" that, with the mostly unflexed toes, provides a saddle-like structure so the bird balances its weight over the central pad of the foot (during day weight further back and digits actively grasp perch). In the region of the pad, the tendon sheath of many birds is unribbed, or only very slightly so, and it is always separated from the tendon of the M. flexor digitorum longus by tendons of the other toe flexor muscles. Passive leg flexion produces no toe flexion in anesthetized Starlings and only after 15-20 min, at the onset of rigor mortis, in freshly sacrificed Starlings. Anesthetized Starlings could not remain perched upon becoming unconscious (ADFM, DTLM intact). Birds whose digital flexor tendons were severed or the locking mechanism eliminated surgically (no ADFM or DTLM), so without ability to flex their toes, slept on the perch in a manner similar to unoperated Starlings (except CAA ∼90°-110°). Consequently, there is no APM or ADFM and the DTLM, although involved in lots of other activities, only acts in perching with active contraction of the digital flexor muscles. © 2012 WILEY PERIODICALS, INC.

  16. Specific conductance identifies perched and ground water lakes.

    Treesearch

    Clarence F. Hawkinson; Elon S. Verry

    1975-01-01

    Shows that lakes can be classified into perched, ground water, and transitional categories according to specific conductance values. Confirms the classification with 10 years of water table measurements in 29 wells and discusses several applications of lake specific conductance values.

  17. Development and evaluation of a SUAS perching system

    NASA Astrophysics Data System (ADS)

    Reynolds, Ryan

    Perching has been proposed as a possible landing technique for Small Unmanned Aircraft Systems (SUAS). The current research study develops an onboard open loop perching system for a fixed-wing SUAS and examines the impact of initial flight speed and sensor placement on the perching dynamics. A catapult launcher and modified COTS aircraft were used for the experiments, while an ultrasonic sensor on the aircraft was used to detect the perching target. Thirty tests were conducted varying the initial launch speed and ultrasonic sensor placement to see if they affected the time the aircraft reaches its maximum pitch angle, since the maximum pitch angle is the optimum perching point for the aircraft. High-speed video was analyzed to obtain flight data, along with data from an onboard inertial measuring unit. The data were analyzed using a model 1, two-way ANOVA to determine if launch speed and sensor placement affect the optimum perching point where the aircraft reaches its maximum pitch angle during the maneuver. The results show the launch speed does affect the time at which the maximum pitch angle occurs, but sensor placement does not. This means a closed loop system will need to adjust its perching distance based on its initial velocity. The sensor placement not having any noticeable effect means the ultrasonic sensor can be placed on the nose or the wing of the aircraft as needed for the design. There was also no noticeable interaction between the two variables. Aerodynamic parameters such as lift, drag, and moment coefficients were derived from the dynamic equations of motion for use in numerical simulations and dynamic perching models.

  18. Complete mitochondrial genome of Sebastes vulpes (Scorpaenidae, Scorpaeniformes) from the East Sea, Korea.

    PubMed

    Jang, Yo-Soon; Oh, Sung-Yong; Lee, Eun Kyung; Myoung, Jung-Goo; Park, Jeong-Ho; Kim, Ki-Yong; Kim, Sung

    2016-01-01

    Sebastes vulpes is considered a valid species despite the presence of extensive hybrids. To obtain the basic genetic intraspecific structure, we analyzed the complete mitogenome of S. vulpes using next-generation sequencing. The complete mitogenome was 16,462 bp in length containing 13 protein-coding genes (PCGs), 2 rRNAs, 22 tRNAs and 1 control region. The complete mitogenome comprised 27.7% A, 26.5% T, 17.1% G and 28.6% C, showing a minor AT bias (54.3%). The initial codon in all PCGs was ATG, excluding COX1 (GTG). The majority of stop codons in the PCGs were TAA, excluding ND1 and ND3 (TAG), ND4 (AGA) and Cytb (incomplete termination codon, T). All tRNAs had a typical cloverleaf structure, excluding tRNA(Ser (AGY)), which lacked the DHU arm. The complete mitogenome of S. vulpes can be used to study hybridisation and on-going speciation.

  19. Cloning and expression analysis of Foxl2 during the reproductive cycle in Korean rockfish, Sebastes schlegeli.

    PubMed

    Mu, Wei J; Wen, Hai S; Li, Ji F; He, Feng

    2013-12-01

    Foxl2 is a member of the winged helix/forkhead family of transcription factors and is known to regulate ovarian aromatase, which plays a crucial role in ovarian differentiation. To address the role of Foxl2 in gonads and brain during gonadal development, we isolated the full-length cDNA of Foxl2 and analyzed its spatiotemporal expression patterns in the viviparous teleost Korean rockfish, Sebastes schlegeli. Tissue distribution pattern revealed that the Foxl2 was detected in the liver, fat, gill, brain, and ovary, but could hardly be found in the testis. Reverse transcriptase PCR suggested that Foxl2 in Korean rockfish may involve in ovary development in the study of expression level during gonads development. It also revealed that the stage of highest expression level for Foxl2 was almost much earlier than cyp19a1a and cyp19a1b during the gonadal development stage in gonads and brain except for cyp19a1a in brain. Furthermore, the expression pattern of Foxl2 as well as aromatases may imply the role of Foxl2 in the up-regulation of aromatases not only in the female fish but also in male.

  20. Potential use of offshore marine structures in rebuilding an overfished rockfish species, bocaccio (Sebastes paucispinis)

    USGS Publications Warehouse

    Love, M.S.; Schroeder, D.M.; Lenarz, W.; MacCall, A.; Bull, A.S.; Thorsteinson, L.

    2006-01-01

    Although bocaccio (Sebastes paucispinis) was an economically important rockfish species along the west coast of North America, overfishing has reduced the stock to about 7.4% of its former unfished population. In 2003, using a manned research submersible, we conducted fish surveys around eight oil and gas platforms off southern California as part of an assessment of the potential value of these structures as fish habitat. From these surveys, we estimated that there was a minimum of 430,000 juvenile bocaccio at these eight structures. We determined this number to be about 20% of the average number of juvenile bocaccio that survive annually for the geographic range of the species. When these juveniles become adults, they will contribute about one percent (0.8%) of the additional amount of fish needed to rebuild the Pacific Coast population. By comparison, juvenile bocaccio recruitment to nearshore natural nursery grounds, as determined through regional scuba surveys, was low in the same year. This research demonstrates that a relatively small amount of artificial nursery habitat may be quite valuable in rebuilding an overfished species.

  1. Gene expression and distribution of antibacterial L-amino acid oxidase in the rockfish Sebastes schlegeli.

    PubMed

    Kitani, Yoichiro; Mori, Tsukasa; Nagai, Hiroshi; Toyooka, Keiko; Ishizaki, Shoichiro; Shimakura, Kuniyoshi; Shiomi, Kazuo; Nagashima, Yuji

    2007-12-01

    Antibacterial factors in the epidermal mucus of fish have a potential importance in the first line of the host defense response to bacterial pathogens. We previously isolated a novel antibacterial protein termed SSAP (Sebastes schlegeli antibacterial protein) from the skin mucus of the rockfish S. schlegeli and identified it as a new member of the L-amino acid oxidase (LAO) family. In the present study, the localization of SSAP in S. schlegeli was investigated by reverse transcription (RT)-PCR, quantitative real time RT-PCR, Western blotting and measurements of LAO and antibacterial activities. SSAP mRNA was expressed dominantly in skin and gill and weakly in ovary or kidney as shown by RT-PCR and real time RT-PCR. The quantity of SSAP mRNA in skin varied among the individuals, ranging from 1.1 to 13.9 ng microg(-1) total RNA, although no relationship was found between the size of fish and gene expression. SSAP was exclusively detected in skin and gill by Western blotting using a specific anti-SSAP antiserum. In addition, the extracts of both tissues apparently showed LAO activity and antibacterial activity against Photobacterium damselae subsp. piscicida. This study demonstrates that SSAP is predominantly synthesized in skin and gill and probably functions as an antibacterial LAO in both tissues.

  2. Cloning and expression analysis of vasa during the reproductive cycle of Korean rockfish, Sebastes schlegeli

    NASA Astrophysics Data System (ADS)

    Mu, Weijie; Wen, Haishen; He, Feng; Li, Jifang; Liu, Miao; Ma, Ruiqin; Zhang, Yuanqing; Hu, Jian; Qi, Baoxia

    2013-03-01

    Vasa, which is a conserved member of the DEAD-box protein family, plays an indispensable role in primordial germ cell proliferation. However, the expression of vasa gene during the reproductive cycle in ovoviviparous fish has not been documented. In this study, the full-length sequence of vasa was obtained from the ovary of Korean rockfish ( Sebastes schlegeli) using reverse transcription-PCR and rapid amplification of cDNA ends. The Vasa with a mature protein of 650 amino acids showed greatest homology (84%) with giant gourami ( Osphronemus goramy) and Pacific bluefin tuna ( Thunnus orientalis). The expression of vasa mRNA in Korean rockfish was detected in gonads only, suggesting its specific role in gonadal development. In addition, seasonal changes in the vasa expression levels were examined in gonads by quantitative real-time PCR. The vasa transcript levels in adult testis were found higher during spermatogenesis than during spermiation. The vasa transcript levels remained relatively high at the early ovary stage but declined during ovary maturation in adult female fish. These results suggest that the vasa gene play an important role in spermatogenesis and early oogenesis during the reproductive cycle of Korean rockfish.

  3. Characterisation of kisspeptin system genes in an ovoviviparous teleost: Sebastes schlegeli.

    PubMed

    Song, Huayu; He, Yan; Ma, Liman; Zhou, Xiaosu; Liu, Xiumei; Qi, Jie; Zhang, Quanqi

    2015-04-01

    Kisspeptins are neuropeptides that play important roles in the reproduction and the onset of puberty in vertebrate by activating their receptor, Kissr. In the present study, we first isolated kiss1 and kissr4 genes from an ovoviviparous fish, the black rockfish (Sebastes schlegeli) by homologue cloning. Phylogenetic analysis indicated that the kiss and kissr of S. schlegeli belonged to kiss1 and kissr4 respectively. Quantitative real-time PCR analysis showed that the kissr4 was expressed mainly in the brain and testis, while the kiss1 was expressed predominantly in the heart of both sexes. As for the different gonadal maturation stages the kiss1 showed different expression patterns in different tissues. During the early development stage, expression levels of the ligand and receptor genes showed similar increasing trends. The promoter region of kissr4 contained several putative transcription factor (TF) binding sites which may have the function of regulating kisspeptin system gene expression, providing potential targets for future in-depth investigation. These results together confirmed that the kisspeptin system in S. schlegeli may be involved in reproduction and other activities. Furthermore, our study laid the groundwork for further learning about the evolution and function of kisspeptin system in fish even vertebrate.

  4. First Report of Clavinema mariae (Nematoda: Philometridae) in Cultured Rockfish, Sebastes schlegeli, in Cheonsuman (Bay), the Republic of Korea.

    PubMed

    Han, Hyun-Ja; Seo, Jung Soo; Park, Jeong Su; Lee, Haeng Lim; Seo, Han Gill; Jung, Sung Hee; Kwon, Se Ryun

    2017-04-01

    In July 2012, philometrid nematodes were discovered in cultured rockfish (Sebastes schlegeli) in Cheonsuman (Bay), the Republic of Korea. The nematodes were detected in the epithelial tissues of the rockfish and were identified as Clavinema mariae based on morphological studies using light and scanning electron microscopy. They revealed the characteristics same as previously identified C. mariae, notably having a long body with narrow posterior half, no caudal projection, a cylindrical-shaped esophagus, a well-developed anterior bulbous part of the esophagus, cephalic papillae, and a dorsal esophageal gland. This is the first confirmation of C. mariae infection in rockfish in Korea.

  5. Numerical modeling of perched water under Yucca Mountain, Nevada

    USGS Publications Warehouse

    Hinds, J.J.; Ge, S.; Fridrich, C.J.

    1999-01-01

    The presence of perched water near the potential high-level nuclear waste repository area at Yucca Mountain, Nevada, has important implications for waste isolation. Perched water occurs because of sharp contrasts in rock properties, in particular between the strongly fractured repository host rock (the Topopah Spring welded tuff) and the immediately underlying vitrophyric (glassy) subunit, in which fractures are sealed by clays that were formed by alteration of the volcanic glass. The vitrophyre acts as a vertical barrier to unsaturated flow throughout much of the potential repository area. Geochemical analyses (Yang et al. 1996) indicate that perched water is relatively young, perhaps younger than 10,000 years. Given the low permeability of the rock matrix, fractures and perhaps fault zones must play a crucial role in unsaturated flow. The geologic setting of the major perched water bodies under Yucca Mountain suggests that faults commonly form barriers to lateral flow at the level of the repository horizon, but may also form important pathways for vertical infiltration from the repository horizon down to the water table. Using the numerical code UNSAT2, two factors believed to influence the perched water system at Yucca Mountain, climate and fault-zone permeability, are explored. The two-dimensional model predicts that the volume of water held within the perched water system may greatly increase under wetter climatic conditions, and that perched water bodies may drain to the water table along fault zones. Modeling results also show fault flow to be significantly attenuated in the Paintbrush Tuff non-welded hydrogeologic unit.

  6. Impact of interannual changes of large scale circulation and hydrography on the spatial distribution of beaked redfish (Sebastes mentella) in the Irminger Sea

    NASA Astrophysics Data System (ADS)

    Núñez-Riboni, Ismael; Kristinsson, Kristján; Bernreuther, Matthias; van Aken, Hendrik M.; Stransky, Christoph; Cisewski, Boris; Rolskiy, Alexey

    2013-12-01

    This study provides evidence of the influence of hydrography and large scale ocean circulation on the geographical distribution of beaked redfish (Sebastes mentella) in the Irminger Sea on the interannual time scale, from 1992 to 2011. The results reveal the average relationship of adult pelagic redfish to their physical habitat from 100 to 800 m depth: the most preferred latitude, longitude, depth, temperature and salinity for redfish are approximately 58°N, 41°W, 557 m, 4.5 °C and 34.87, respectively. The redfish habitat corresponds in a temperature-salinity (TS) diagram to a mixing triangle between East Greenland Current Water (EGCW), Labrador Sea Water (LSW) and Irminger Current Water (ICW). The geographical centre of mass of the redfish distribution (as revealed by acoustic fish density) indicates displacements from year to year. Changes in hydrographic conditions were investigated in detail for possible reasons for these displacements. Empirical Orthogonal Analysis reveals that maximum variations of water mass volume on an interannual time-scale in the study region correspond to ICW and LSW changes, while EGCW remains comparatively stable. Indices of redfish geographical centroid, LSW volume, ICW temperature and Subpolar Gyre (SPG) intensity suggest that the geographical redfish displacements are closely related to interannual changes of ICW modulated by the SPG intensity with a lag of 1 or 2 years. In comparison, LSW seems to have no impact on the redfish distribution at the studied depth range. The time lag between ICW and redfish displacements indicates an indirect influence of temperature on redfish. Hence, changes of chlorophyll-a (from satellite imagery), as a proxy for primary production, were used in a first approach to study the role of food availability. The analysis is based on acoustic and trawl data from nine expeditions coordinated by the International Council for the Exploration of the Sea (ICES), around 71,000 hydrographic stations from the

  7. Food of alewives, yellow perch, spottail shiners, trout-perch, and slimy and fourhorn sculpins in southeastern Lake Michigan

    USGS Publications Warehouse

    Wells, LaRue

    1980-01-01

    Stomachs of 1, 064 alewives (Alosa pseudoharengus), 1, 103 yellow perch (Perca flavescens), 246 spottail shiners (Notropis hudsonius), 288 trout-perch (Percopsis omiscomaycus), 454 slimy sculpins (Cottus cognatus), and 562 fourhorn sculpins (Myoxocephalus quadricornis) from Lake Michigan were examined for food contents. Fish were sampled primarily from March to November and nearly all were caught at the bottom in the southeastern part of the lake near Saugatuck, Michigan. Depths of capture (m) were: alewives, 5 to 110; yellow perch, 5 to 26; spottail shiners, 5 to 31; trout-perch, 9 to 46; slimy sculpins, 31 to 91; and fourhorn sculpins, 73 to 110. Alewives, particularly those less than 140 mm long, fed chiefly on zooplankton; Pontoporeia usually constituted most of the rest of the food, although Mysis and immature midges were occasionally eaten in considerable quantity. Yellow perch ate primarily Pontoporeia, fish eggs, Mysis, and crayfish; Pontoporeiawas consumed most heavily by perch less than 250 mm long and those in relatively deep water, fish (mainly slimy sculpins) by those 200 mm long or longer, Mysis by those in deep water, and crayfish by those on rocky bottom. Spottail shiners fed most commonly on immature midges, Pontoporeia, zooplankton, fingernail clams, and (in July only) fish eggs; immature midges were eaten mainly by shiners in shallow water; and Pontoporeia by those in deeper areas. The diet of trout-perch was strongly dominated by Pontoporeia and immature midges. Slimy sculpins ate Pontoporeia almost exclusively. Fourhorn sculpins fed almost entirely on Mysis and Pontoporeia Pontoporeia was particularly important in the diet of the larger fish.

  8. Food of alewives, yellow perch, spottail shiners, trout-perch, and slimy and fourhorn sculpins in southeastern Lake Michigan

    USGS Publications Warehouse

    Wells, LaRue

    1980-01-01

    Stomachs of 1,064 alewives (Alosa pseudoharengus), 1,103 yellow perch (Perca flavescens), 246 spottail shiners (Notropis hudsonius), 288 trout-perch (Percopsis omiscomaycus), 454 slimy sculpins (Cottus cognatus), and 562 fourhorn sculpins (Myoxocephalus quadricornis) from Lake Michigan were examined for food contents. Fish were sampled primarily from March to November and nearly all were caught at the bottom in the southeastern part of the lake near Saugatuck, Michigan. Depths of capture (m) were: alewives, 5 to 110; yellow perch, 5 to 26; spottail shiners, 5 to 31; trout-perch, 9 to 46; slimy sculpins, 31 to 91; and fourhorn sculpins, 73 to 110. Alewives, particularly those less than 140 mm long, fed chiefly on zooplankton; Pontoporeia usually constituted most of the rest of the food, although Mysis and immature midges were occasionally eaten in considerable quantity. Yellow perch ate primarily Pontoporeia, fish eggs, Mysis, and crayfish; Pontoporeia was consumed most heavily by perch less than 250 mm long and those in relatively deep water, fish (mainly slimy sculpins) by those 200 mm long or longer, Mysis by those in deep water, and crayfish by those on rocky bottom. Spottail shiners fed most commonly on immature midges, Pontoporeia, zooplankton, fingernail clams, and (in July only) fish eggs; immature midges were eaten mainly by shiners in shallow water; and Pontoporeia by those in deeper areas. The diet of trout-perch was strongly dominated by Pontoporeia and immature midges. Slimy sculpins ate Pontoporeia almost exclusively. Fourhorn sculpins fed almost entirely on Mysis and Pontoporeia; Pontoporeia was particularly important in the diet of the larger fish.

  9. Indirect effects of sea otters on rockfish (Sebastes spp.) in giant kelp forests.

    PubMed

    Markel, Russell W; Shurin, Jonathan B

    2015-11-01

    Sea otters are a classic example of a predator controlling ecosystem productivity through cascading effects on basal, habitat-forming kelp species. However, their indirect effects on other kelp-associated taxa like fishes are poorly understood. We examined the effects of sea otter (Enhydra lutris) reintroduction along the west coast of Vancouver Island, Canada on giant kelp (Macrocystis pyrifera) distributions and the trophic niches and growth of two common kelp forest fishes, black (Sebastes melanops) and copper (S. caurinus) rockfishes. We sampled 47 kelp forests, and found that red sea urchins (Strongylocentrotus franciscanus) were eliminated in the presence of otters, and that kelp forests were 3.7 times deeper and 18.8 times larger. Despite order-of-magnitude differences in kelp forest size, adult black and copper rockfishes contained less kelp-derived carbon in their tissues (as measured by stable isotopes of C and N) in regions with otters. Adults of both species had higher mean trophic positions in the presence of otters, indicating more frequent consumption of higher trophic level prey such as fishes. Smaller trophic niche space of rockfishes in the presence of otters indicated a higher degree of trophic specialization. Juvenile black rockfishes rapidly shifted to higher kelp-carbon contents, trophic positions, and body condition factors after settling in kelp forests. The relationships of growth to length, percentage of kelp carbon, and trophic position varied between the two regions, indicating that potential effects of kelp forest size on trophic ontogeny may also affect individual performance. Our results provide evidence that the indirect effects of otters on rockfishes arise largely through the creation of habitat for fishes and other prey rather than a direct trophic connection through invertebrates or other consumers of kelp productivity.

  10. Pharmacokinetics of long-acting cefovecin in copper rockfish (Sebastes caurinus).

    PubMed

    Seeley, Kathryn E; Wolf, Karen N; Bishop, Melissa A; Turnquist, Megan; KuKanich, Butch

    2016-03-01

    To assess the pharmacokinetic properties of cefovecin in a cold-water teleost species. 10 healthy adult copper rockfish (Sebastes caurinus), sex unknown. Cefovecin (16 mg/kg) was administered SC to the rockfish. Blood samples were collected at predetermined points for measurement of plasma cefovecin concentrations (3 samples/fish). Plasma cefovecin concentrations were measured via liquid chromatography with mass spectrometry. Pharmacokinetic analysis was performed by means of naïve pooled analysis and compartmental modeling. Plasma protein binding of cefovecin was determined by ultrafiltration. Cefovecin administration appeared to be well tolerated by the rockfish. Pharmacokinetic analysis resulted in a maximum plasma concentration of 104.8 μg/mL at 2.07 hours after administration. Plasma terminal half-life was 32.5 hours, and area under the curve was 5,132 h·g/mL. Plasma protein binding was low (< 10%) for plasma concentrations of 10 and 100 μg of cefovecin/mL when assessed at 7.8° and 20°C. Plasma concentrations > 1 μg/mL persisted for the full 7-day follow-up period. SC administration of cefovecin to copper rockfish at a dose of 16 mg/kg yielded plasma concentrations > 1 μg/mL that persisted to 7 days, but some interindividual variability was observed. The low degree of plasma protein binding but high circulating concentration of free drug may allow an extended administration interval in rockfish. Studies are needed to assess the efficacy and safety of this dose in rockfish.

  11. Development of a bio-inspired UAV perching system

    NASA Astrophysics Data System (ADS)

    Xie, Pu

    Although technologies of unmanned aerial vehicles (UAVs) including micro air vehicles (MAVs) have been greatly advanced in the recent years, it is still very difficult for a UAV to perform some very challenging tasks such as perching to any desired spot reliably and agilely like a bird. Unlike the UAVs, the biological control mechanism of birds has been optimized through millions of year evolution and hence, they can perform many extremely maneuverability tasks, such as perching or grasping accurately and robustly. Therefore, we have good reason to learn from the nature in order to significantly improve the capabilities of UAVs. The development of a UAV perching system is becoming feasible, especially after a lot of research contributions in ornithology which involve the analysis of the bird's functionalities. Meanwhile, as technology advances in many engineering fields, such as airframes, propulsion, sensors, batteries, micro-electromechanical-system (MEMS), and UAV technology is also advancing rapidly. All of these research efforts in ornithology and the fast growing development technologies in UAV applications are motivating further interests and development in the area of UAV perching and grasping research. During the last decade, the research contributions about UAV perching and grasping were mainly based on fixed-wing, flapping-wing, and rotorcraft UAVs. However, most of the current researches in UAV systems with perching and grasping capability are focusing on either active (powered) grasping and perching or passive (unpowered) perching. Although birds do have both active and passive perching capabilities depending on their needs, there is no UAV perching system with both capabilities. In this project, we focused on filling this gap. Inspired by the anatomy analysis of bird legs and feet, a novel perching system has been developed to implement the bionics action for both active grasping and passive perching. In addition, for developing a robust and

  12. Draft genome sequence of Staphylococcus saprophyticus subsp. saprophyticus M1-1, isolated from the gills of a Korean rockfish, Sebastes schlegeli Hilgendorf, after high hydrostatic pressure processing.

    PubMed

    Kim, Bong-Soo; Kim, Chong-Tai; Park, Bang Heon; Kwon, Sujin; Cho, Yong-Jin; Kim, Namsoo; Kim, Chul-Jin; Chun, Jongsik; Kwak, Jangyul; Maeng, Jin-Soo

    2012-08-01

    A bacterium designated M1-1 was isolated from the gills of a Korean rockfish, Sebastes schlegeli Hilgendorf, after high hydrostatic pressure processing. Studies of 16S rRNA phylogeny and comparative genomics demonstrated that the isolate belongs to Staphylococcus saprophyticus subsp. saprophyticus. Here, we report the draft genome sequence of S. saprophyticus subsp. saprophyticus M1-1 (KACC 16562).

  13. Histological observation of germ cell development and discovery of spermatophores in ovoviviparous black rockfish ( Sebastes schlegeli Hilgendorf) in reproductive season

    NASA Astrophysics Data System (ADS)

    Feng, Junrong; Liu, Liming; Jiang, Haibin; Wang, Maojian; Du, Rongbin

    2014-10-01

    Black rockfish ( Sebastes schlegeli) is an important species for culture; however, its reproductive characteristics have not been fully documented. In this study, we investigated the morphology and developmental process of germ cells in this ovoviviparous rockfish in reproductive season (October 2011-November 2012) with histological methods. We found that the gonad of mature fish showed notable seasonal changes in developmental characteristics and morphological structure. The sperm cells matured during a period lasting from October to December, significantly earlier than the oocytes did. A large number of spermatozoa and other cells occurred in testis at different developmental stages. Vitellogenesis in oocytes began in October, and gestation appeared in April next year. Spermatophores were discovered for the first time in Sebastes, which assembled in testis, main sperm duct, oviduct and genital tract, as well as ovarian cavity in October and April. These organs may serve either as production or hiding places for spermatophores and spermatozoa which were stored and transported in form of spermatophores. Testicular degeneration started from the distal part of testis in April, with spermatophores assembled in degenerating testis and waiting for transportation. The copulation probably lasted for a long period, during which the spermatozoa were discharged in batches as spermatophores. These spermatophores were coated with sticky materials secreted from the interstitial areas of testis and the main sperm duct, then transported into ovary.

  14. Perching Dynamics and Development of a Simple Model

    NASA Astrophysics Data System (ADS)

    Puopolo, Michael; Jacob, Jamey; Reynolds, Ryan

    2013-11-01

    Aerodynamicists with a vision for bird-like aircraft have been forced to develop new ways of modeling extremely agile flight systems, and in recent years there has been a growing variety of creative approaches that incorporate computer methods, empirical data, and unsteady flow theory. However, there remains a lack of simple and easily transferable models that can be used to predict and control motion of a fixed-wing, perching aircraft in the low Reynolds number flow regime. The authors have developed a simple dynamic model for a perching vehicle with a common fixed wing configuration that uses only input of the system design parameters, in addition to other relevant widely available information, and does not rely on wind tunnel measurements, CFD analysis or other rigorous forms of system identification. The resulting model is presented with a comparison of model simulations to flight data from a perching UAV.

  15. REPRODUCTIVE PHYSIOLOGY OF YELLOW PERCH (PERCA FLAVESCENS): ENVIRONMENTAL AND ENDOCRINOLOGICAL CUES

    EPA Science Inventory

    An understanding of the mechanisms involved in the regulation of reproductive processes in yellow perch is fundamental for intensive culture of this commercially important, freshwater, perciform fish. This paper describes the annual reproductive cycle of female and male perch. It...

  16. Bioaccumulation of decamethylcyclopentasiloxane in perch in Swedish lakes.

    PubMed

    Kierkegaard, Amelie; Bignert, Anders; McLachlan, Michael S

    2013-10-01

    Decamethylcyclopentasiloxane (D5), a high production volume chemical used in personal care products, enters the environment both via air and sewage treatment plant (STP) recipients. It has been found in fish, and there is concern that it may be a bioaccumulative substance. In this work D5 was analyzed in perch from six Swedish lakes that did not receive STP effluent, and in perch and sediment from six lakes that received STP effluent. In the lakes receiving the STP effluent, the D5 concentrations in sediment varied over three orders of magnitude and were correlated with the number of persons connected to the STP normalized to the surface area of the receiving body. In the lakes not receiving effluent, the D5 levels in perch were all below the LOQ, while D5 was above the LOQ in almost all perch from lakes that received effluent. The D5 concentrations in perch and sediment from the lakes receiving STP effluent were correlated. This shows that STP effluent is a much more important source of D5 to aquatic ecosystems than atmospheric deposition, and that the risk of adverse effects of D5 on aquatic life will be greatest in small recipients receiving large amounts of STP effluent. The bioaccumulation of D5 was compared to that of PCB 180 on the basis of multimedia bioaccumulation factors (mmBAFs), which describe the fraction of the contaminant present in the whole aquatic environment (i.e. water and surface sediment) that is transferred to the fish. In four of the six lakes the mmBAF of D5 was >0.3 of the mmBAF of PCB 180. Given that PCB 180 is a known highly bioaccumulative chemical, this indicates that the bioaccumulation of D5 in perch is considerable.

  17. Access to Barrier Perches Improves Behavior Repertoire in Broilers

    PubMed Central

    Ventura, Beth A.; Siewerdt, Frank; Estevez, Inma

    2012-01-01

    Restriction of behavioral opportunities and uneven use of space are considerable welfare concerns in modern broiler production, particularly when birds are kept at high densities. We hypothesized that increased environmental complexity by provision of barrier perches would help address these issues by encouraging perching and enhancing use of the pen space across a range of stocking densities. 2,088 day-old broiler chicks were randomly assigned to one of the following barrier and density treatment combinations over four replications: simple barrier, complex barrier, or control (no barrier) and low (8 birds/m2), moderate (13 birds/m2), or high (18 birds/m2) density. Data were collected on focal birds via instantaneous scan sampling from 2 to 6 weeks of age. Mean estimates per pen for percent of observations seen performing each behavior, as well as percent of observations in the pen periphery vs. center, were quantified and submitted to an analysis of variance with week as the repeated measure. Barrier perches, density and age affected the behavioral time budget of broilers. Both simple and complex barrier perches effectively stimulated high perching rates. Aggression and disturbances were lower in both barrier treatments compared to controls (P<0.05). Increasing density to 18 birds/m2 compared to the lower densities suppressed activity levels, with lower foraging (P<0.005), decreased perching (P<0.0001) and increased sitting (P = 0.001) earlier in the rearing period. Disturbances also increased at higher densities (P<0.05). Use of the central pen area was higher in simple barrier pens compared to controls (P<0.001), while increasing density above 8 birds/m2 suppressed use of the central space (P<0.05). This work confirms some negative effects of increasing density and suggests that barrier perches have the potential to improve broiler welfare by encouraging activity (notably by providing accessible opportunities to perch), decreasing aggression and disturbances

  18. Botany: specialized bird perch aids cross-pollination.

    PubMed

    Anderson, Bruce; Cole, William W; Barrett, Spencer C H

    2005-05-05

    Birds may hover over or perch on flowers when feeding on nectar, and this assists cross-pollination if they then visit other plants. Here we investigate the curious sterile inflorescence axis of the South African Cape endemic 'rat's tail' plant (Babiana ringens, Iridaceae), whose function--unlike in other bird-pollinated plants--is exclusively to provide a perch for foraging birds. We find that this structure promotes the plant's mating success by causing the malachite sunbird (Nectarinia famosa), its main pollinator, to adopt a position ideal for the cross-pollination of its unusual ground-level flowers.

  19. Yellow Perch in Lake Erie, Student Guide and Teacher Guide. OEAGLS Investigation 9.

    ERIC Educational Resources Information Center

    Fortner, Rosanne; Reil, Gabriele

    This investigation focuses on the life cycle of the yellow perch, the factors which can affect perch populations at each stage of the life cycle, and the methods used to manage Lake Erie perch populations. The investigation is presented in the form of a teachers' guide and a students' guide. It consists of two games related to the management of…

  20. Comprehensive characterization of three glutathione S-transferase family proteins from black rockfish (Sebastes schlegelii).

    PubMed

    Jayasinghe, J D H E; Bathige, S D N K; Nam, Bo-Hye; Noh, Jae Koo; Lee, Jehee

    2016-11-01

    Glutathione S-transferases (GSTs, EC 2.5.1.18) are categorized as phase II enzymes, which form an important multifunctional family associated with a wide variety of catalytic activities. GSTω, GSTρ, and GSTθ are cytosolic GSTs which have been extensively studied in a variety of organisms; however, few studies have focused on teleosts. Those paralogs from black rockfish (Sebastes schlegelii; RfGSTω, RfGSTρ, and RfGSTθ, respectively) were molecularly, biochemically, and functionally characterized to determine their antioxidant extent and protective aptitudes upon pathogenic stress. RfGSTω, RfGSTρ, and RfGSTθ, contained open reading frames of 717bp, 678bp, and 720bp respectively, which encoded respective proteins of 239, 226, and 240 amino acids in length. In silico analysis revealed that all RfGSTs possessed characteristic N-terminal domains bearing glutathione (GSH)-binding sites, and C-terminal domains containing substrate-binding sites. Recombinant RfGSTω (rRfGSTω) catalyzed the conjugation of GSH to dehydroascorbate (DHA), while rRfGSTθ and rRfGSTρ catalyzed to the model GST substrate 1-Chloro-2,4-dinitrobenzene (CDNB). Kinetic analysis revealed variation in Km and Vmax values for each rRfGST, indicating their different conjugation rates. The optimum conditions (pH and temperature) and inhibition assays of each protein demonstrated different optimal ranges showing their wide range of activity as an assembly. RfGSTω and RfGSTθ paralogs demonstrated their antioxidant potential towards H2O2 and heavy metals (Cd, Zn, and Cu) in vitro, while RfGSTρ had an antioxidant potential only towards heavy metals (Zn and Cu). Though all the paralogs were ubiquitously expressed in different magnitudes, RfGSTω was highly expressed in blood, whereas RfGSTρ and RfGSTθ were highly expressed in liver. The mRNA expression of RfGSTω and RfGSTθ, upon Streptococcus iniae and poly I:C stimulation, revealed a significantly up-regulated expression, whereas RfGSTρ m

  1. Bird Perches Increase Forest Seeds on Puerto Rican Landslides.

    Treesearch

    Aaron B. Shiels; Lawrence R. Walker

    2003-01-01

    Landslides result in the loss of vertical vegetative structure, soil nutrients, and the soil seed bank. These losses impede timely recovery of tropical forest communities. In this study we added bird perches to six Puerto Rican landslides with three types of surfaces (bare, climbing fern, grass) in an effort to facilitate inputs of forest seeds through bird dispersal...

  2. A bacterial disease of yellow perch (Peres flavescens)

    USGS Publications Warehouse

    Ross, A.J.; Nordstrom, P.R.; Bailey, J.E.; Heaton, J.H.

    1960-01-01

    Examination of the freshly dead perch revealed the presence of multiple petechiae, which were visible externally as well as in the dorsal musculature. The peritoneal cavity showed evidence of inflammation and contained a bloody ascitic fluid. A number of the dead fish were placed on ice and shipped to the Western Fish Disease Laboratory in Seattle for bacteriological studies.

  3. Late Holocene paleoenvironmental and paleoclimatic evolution at Elaiussa Sebaste archeological area (South-Eastern Turkey): preliminary results.

    NASA Astrophysics Data System (ADS)

    Melis, Romana; Bernasconi, Maria Pia; Colizza, Ester; Di Rita, Federico; Equini Schneider, Eugenia; Montenegro, Maria Eugenia; Pugliese, Nevio

    2013-04-01

    Geological disciplines are increasingly applied to archaeological research. Their potentialities are able to cover numerous fields of research, since they can become very interesting tools to define the ancient environments, the origin of the human settlements and the natural and anthropic processes which occurred through the evolution of the territory. Elaiussa Sebaste (Mersin region, South-Eastern coast of the Turkey), which was an important coastal town from the II century BC to VII century AD, may represent a noteworthy field of application of geological disciplines. This site was one of the main trading harbours of the Mediterranean (from the Augustan to the Byzantine era) growing in the Augustan period and maintaining its prestige until the late Empire and the Byzantine era. Actually it was the intersection of the most important shipping and land routes among Syria, Egypt and the Anatolian peninsula. The evolution of the coastal environment around this town has been continuously modified by men along its history. The most evident modification occurred North and South the promontory of Elaiussa-Sebaste bay, i.e. the construction of two harbours, which have been subsequently buried by not well defined events. The definition of the geological processes controlling the evolution of the coastal area during the last 3000 years, should become essential to reconstruct the succession of the palaeoenvironments of Elaiussa Sebaste, including the decline of the harbours. With regard to this topic, the geomorphologic analysis reveals the complex interactions among tectonics, erosion and sedimentation in this coastal area in both, emerged and in ancient times submerged settings facing the archaeological site. During the summer 2012, a geological survey allowed us to drill nine boreholes along the land-to-sea transects in both harbours. Preliminary observations indicate the stratigraphic evolution from restricted to open marine coastal environments. Sedimentology

  4. Demonstrations of bio-inspired perching landing gear for UAVs

    NASA Astrophysics Data System (ADS)

    Tieu, Mindy; Michael, Duncan M.; Pflueger, Jeffery B.; Sethi, Manik S.; Shimazu, Kelli N.; Anthony, Tatiana M.; Lee, Christopher L.

    2016-04-01

    Results are presented which demonstrate the feasibility and performance of two concepts of biologically-inspired landing-gear systems that enable bird-sized, unmanned aerial vehicles (UAV's) to land, perch, and take-off from branchlike structures and/or ledges. The first concept follows the anatomy of birds that can grasp ahold of a branch and perch as tendons in their legs are tensioned. This design involves a gravity-activated, cable-driven, underactuated, graspingfoot mechanism. As the UAV lands, its weight collapses a four-bar linkage pulling a cable which curls two opposing, multi-segmented feet to grasp the landing target. Each foot is a single, compliant mechanism fabricated by simultaneouly 3D-printing a flexible thermo-plastic and a stiffer ABS plastic. The design is optimized to grasp structures over a range of shapes and sizes. Quasi-static and flight tests of this landing gear affixed to RC rotorcraft (24 cm to 550 cm in diameter) demonstrate that the aircraft can land, perch, and take-off from a tree branch, rectangular wood board, PVC pipe, metal hand rail, chair armrest, and in addition, a stone wall ledge. Stability tests show that perching is maintained under base and wind disturbances. The second design concept, inspired by roosting bats, is a two-material, 3D-printed hooking mechanism that enables the UAV to stably suspend itself from a wire or small-diameter branch. The design balances structural stiffness for support and flexibility for the perching process. A flight-test demonstrates the attaching and dis-engaging of a small, RC quadcopter from a suspended line.

  5. The effect of perch availability during pullet rearing and egg laying on the behavior of caged White Leghorn hens

    USDA-ARS?s Scientific Manuscript database

    Enriched cages, compared to conventional cages, allow egg laying strains of chickens to meet some behavioral needs, including the high motivation to perch. The objective of this study was to determine if perch availability during rearing affected perch use as adults and if perch presence affected ea...

  6. Branching out in locomotion: the mechanics of perch use in birds and primates.

    PubMed

    Bonser, R H

    1999-06-01

    Many animals use thin perches, such as the branches of trees, as locomotory substrates. In this paper, I have reviewed the literature concerned with measurements of locomotory forces made by birds and primates on thin and flexible substrates. Through a knowledge of the locomotory forces exerted by animals when using different substrates, the mechanical cost of their use can be established. We are just beginning to learn about the magnitude and patterns of force production in various branch-using vertebrates, primarily as a result of the development of instrumented perches. Instrumented perches have been designed to measure the forces produced by birds and primates when leaping from rigid and flexible horizontal and flexible vertical perches, and also from instrumented handgrips during brachiation. The development of these techniques for birds and primates allows us to compare the way in which they use perches as locomotory substrates. In both birds and primates, the magnitudes of landing forces are smaller than those during take-off. Two explanations have been proposed; the difference is either a consequence of perch compliance or it is a strategic decision to be cautious of 'new' perches. Leaps from flexible perches may be somewhat inefficient because considerable energy is dissipated in bending the perch, and this energy may remain unrecovered when the animal leaves contact with the perch.

  7. Ultraviolet radiation influences perch selection by a neotropical poison-dart frog.

    PubMed

    Kats, Lee B; Bucciarelli, Gary M; Schlais, David E; Blaustein, Andrew R; Han, Barbara A

    2012-01-01

    Ambient ultraviolet-B radiation can harm amphibian eggs, larvae and adults. However, some amphibians avoid UV-B radiation when given the opportunity. The strawberry poison dart frog, Oophaga pumilio, is diurnal and males vocalize throughout the day in light gaps under forest canopies that expose them to solar radiation. Previous studies have demonstrated that males calling from high perches are more successful at mating than those at lower perches. We investigated whether frogs at higher perches receive more ultraviolet-B than those calling from lower perches. We also investigated whether frogs on perches receiving relatively low ultraviolet-B levels maintained their positions for longer compared to individuals calling from perches receiving higher levels of ultraviolet-B. Finally, since it has been hypothesized that some animals utilize levels of UV-A as a visual cue to avoid UV-B damage, we artificially elevated ultraviolet-A levels to examine whether males exposed to artificially elevated ultraviolet-A abandoned their perches sooner compared to males exposed to visible light. We found that frogs called from perches receiving low ultraviolet-B regardless of perch height, and that frogs maintain their positions longer on perches receiving low ultraviolet-B compared to perches receiving even slightly higher ultraviolet-B levels. Exposing the frogs to artificially elevated levels of ultraviolet-A radiation caused males to move off of their perches faster than when they were exposed to a control light source. These experiments suggest that ultraviolet radiation plays an important role in frog behavior related to perch selection, even in rainforests where much of the solar radiation is shielded by the forest canopy.

  8. Ultraviolet Radiation Influences Perch Selection by a Neotropical Poison-Dart Frog

    PubMed Central

    Kats, Lee B.; Bucciarelli, Gary M.; Schlais, David E.; Blaustein, Andrew R.; Han, Barbara A.

    2012-01-01

    Ambient ultraviolet-B radiation can harm amphibian eggs, larvae and adults. However, some amphibians avoid UV-B radiation when given the opportunity. The strawberry poison dart frog, Oophaga pumilio, is diurnal and males vocalize throughout the day in light gaps under forest canopies that expose them to solar radiation. Previous studies have demonstrated that males calling from high perches are more successful at mating than those at lower perches. We investigated whether frogs at higher perches receive more ultraviolet-B than those calling from lower perches. We also investigated whether frogs on perches receiving relatively low ultraviolet-B levels maintained their positions for longer compared to individuals calling from perches receiving higher levels of ultraviolet-B. Finally, since it has been hypothesized that some animals utilize levels of UV-A as a visual cue to avoid UV-B damage, we artificially elevated ultraviolet-A levels to examine whether males exposed to artificially elevated ultraviolet-A abandoned their perches sooner compared to males exposed to visible light. We found that frogs called from perches receiving low ultraviolet-B regardless of perch height, and that frogs maintain their positions longer on perches receiving low ultraviolet-B compared to perches receiving even slightly higher ultraviolet-B levels. Exposing the frogs to artificially elevated levels of ultraviolet-A radiation caused males to move off of their perches faster than when they were exposed to a control light source. These experiments suggest that ultraviolet radiation plays an important role in frog behavior related to perch selection, even in rainforests where much of the solar radiation is shielded by the forest canopy. PMID:23251505

  9. Habitat change in a perched dune system along Lake Superior

    USGS Publications Warehouse

    Loope, Walter L.; McEachern, A. Kathryn; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

    1998-01-01

    Episodes of habitat change, driven by changes in levels of the Great Lakes, must be considered when assessing human effects upon coastal vegetation and rare species. Paleoecological studies, baseline inventories, and long-term monitoring programs within the Grand Sable Dunes, a perched-dune system along Lake Superior, provide a window on vegetation change at different spatial and temporal scales and also provide an illustrative case study.

  10. Water displacement during sparging under perched water-table conditions

    SciTech Connect

    DiGiulio, D.C.

    1995-12-31

    The feasibility of using sparging to purposefully displace perched water in silt loam soils was evaluated at a field site in northwestern Oklahoma. Soils and groundwater are contaminated with petroleum hydrocarbons, trichloroethene (TCE), and vinyl chloride. During sparging, a transient response in water level measurements was observed in observation wells which is attributed to water displacement. Evidence of water displacement was manifested by water-table collapse upon the cessation of sparging.

  11. The effect of perches in cages during pullet rearing and egg laying on hen performance, foot health, and plumage.

    PubMed

    Hester, P Y; Enneking, S A; Jefferson-Moore, K Y; Einstein, M E; Cheng, H W; Rubin, D A

    2013-02-01

    Enrichment of pullet cages with perches has not been studied. Our objective was to determine if access to metal perches during all or part of the life cycle of caged White Leghorns affected egg traits, foot health, and feather condition. Treatment 1 represented control chickens that never had access to perches during their life cycle. Treatment 2 hens had perches only during the egg laying phase of the life cycle (17 to 71 wk of age), whereas treatment 3 chickens had perches during the pullet phase (0 to 16.9 wk of age). Treatment 4 chickens always had access to perches (0 to 71 wk of age). Comparisons between chickens that always had perches with controls that never had perches showed similar performance relative to egg production, cracked eggs, egg weight, shell weight, % shell, and shell thickness. More dirty eggs occurred in laying cages with perches. Feed usage increased resulting in poorer feed efficiency in hens with perch exposure during the pullet phase with no effect during egg laying. Perches did not affect hyperkeratosis of toes and feet. The back claw at 71 wk of age broke less if hens had prior experience with perches during the pullet phase. In contrast, during egg laying, the back claw at 71 wk of age broke more due to the presence of perches in laying cages. Perches in laying cages resulted in shorter trimmed claws and improved back feather scores, but caused poorer breast and tail feather scores. In conclusion, enriching conventional cages with perches during the entire life cycle resulted in similar hen performance compared with controls. Fewer broken back claws but poorer feed efficiency occurred because of prior experience with perches as pullets. Perch presence during egg laying improved back feather scores with more trimmed nails but caused more dirty eggs, broken back claws, and poorer breast and tail feather scores. Although perches allow chickens to express their natural perching instinct, it was not without causing welfare problems.

  12. Characterization of perch rhabdovirus (PRV) in farmed grayling Thymallus thymallus.

    PubMed

    Gadd, Tuija; Viljamaa-Dirks, Satu; Holopainen, Riikka; Koski, Perttu; Jakava-Viljanen, Miia

    2013-10-11

    Two Finnish fish farms experienced elevated mortality rates in farmed grayling Thymallus thymallus fry during the summer months, most typically in July. The mortalities occurred during several years and were connected with a few neurological disorders and peritonitis. Virological investigation detected an infection with an unknown rhabdovirus. Based on the entire glycoprotein (G) and partial RNA polymerase (L) gene sequences, the virus was classified as a perch rhabdovirus (PRV). Pairwise comparisons of the G and L gene regions of grayling isolates revealed that all isolates were very closely related, with 99 to 100% nucleotide identity, which suggests the same origin of infection. Phylogenetic analysis demonstrated that they were closely related to the strain isolated from perch Perca fluviatilis and sea trout Salmo trutta trutta caught from the Baltic Sea. The entire G gene sequences revealed that all Finnish grayling isolates, and both the perch and sea trout isolates, were most closely related to a PRV isolated in France in 2004. According to the partial L gene sequences, all of the Finnish grayling isolates were most closely related to the Danish isolate DK5533 from pike. The genetic analysis of entire G gene and partial L gene sequences showed that the Finnish brown trout isolate ka907_87 shared only approximately 67 and 78% identity, respectively, with our grayling isolates. The grayling isolates were also analysed by an immunofluorescence antibody test. This is the first report of a PRV causing disease in grayling in Finland.

  13. Reproductive health of yellow perch Perca flavescens in selected tributaries of the Chesapeake Bay

    USGS Publications Warehouse

    Blazer, Vicki; Pinkney, Alfred E.; Jenkins, Jill A.; Iwanowicz, Luke R.; Minkkinen, Steven; Draugelis-Dale, Rassa O.; Uphoff, James H.

    2013-01-01

    Reduced recruitment of yellow perch has been noted for a number of years in certain urbanized watersheds (South and Severn Rivers) of the Chesapeake Bay. Other rapidly developing watersheds such as Mattawoman Creek are more recently showing evidence of reduced recruitment of anadromous fishes. In this study, we used a battery of biomarkers to better document the reproductive health of adult yellow perch collected during spring spawning in 2007–2009. Perch were collected in the South and Severn Rivers, Mattawoman Creek and the less developed Choptank and Allen's Fresh watersheds for comparison. Gonadosomatic indices, plasma reproductive hormone concentrations, plasma vitellogenin concentrations and gonad histology were evaluated in mature perch of both sexes. In addition, sperm quantity (cell counts) and quality (total and progressive motility, spermatogenic stage and DNA integrity), were measured in male perch. Many of these biomarkers varied annually and spatially, with some interesting statistical results and trends. Male perch from the Choptank and Allen's Fresh had generally higher sperm counts. In 2008 counts were significantly lower in the perch from the Severn when compared to other sites. The major microscopic gonadal abnormality in males was the proliferation of putative Leydig cells, observed in testes from Severn and less commonly, Mattawoman Creek perch. Observations that could significantly impact egg viability were an apparent lack of final maturation, abnormal yolk and thin, irregular zona pellucida. These were observed primarily in ovaries from Severn, South and less commonly Mattawoman Creek perch. The potential association of these observations with urbanization, impervious surface and chemical contaminants is discussed.

  14. Ecology and population status of trout-perch (Percopsis omiscomaycus) in western Lake Erie

    USGS Publications Warehouse

    Kocovsky, Patrick; Stoneman, Andrea T.; Kraus, Richard T.

    2014-01-01

    Trout-perch Percopsis omiscomaycus is among the most abundant benthic species in Lake Erie, but comparatively little is known about its ecology. Although others have conducted extensive studies on trout-perch ecology, those efforts predated invasions of white perch Morone americana, Dreissena spp., Bythotrephes longimanus and round goby Neogobius melanostomus, suggesting the need to revisit past work. Trout-perch were sampled with bottom trawls at 56 sites during June and September 2010. We examined diets, fecundity, average annual mortality, sex ratio, and long-term population trends at sites sampled since 1961. Trout-perch abundance fluctuated periodically, with distinct shorter- (4-year) and longer-term (over period of 50 years) fluctuations. Males had higher average annual mortality than females. Both sexes were equally abundant at age 0, but females outnumbered males 4:1 by age 2. Diets of trout-perch were dominated by macroinvertebrates, particularly chironomids and Hexagenia sp. Size distributions of trout-perch eggs varied widely and exhibited multiple modes indicative of protracted batch spawning. A review of the few other studies of trout-perch revealed periodic fluctuations in sex ratio of adults, which in light of our evidence of periodicity in abundance suggests the potential for sex-ratio-mediated intrinsic population regulation. Despite the introduction of numerous invasive species in Lake Erie, trout-perch remain one of the most abundant benthic invertivores and the population is relatively stable.

  15. Competition between nonindigenous ruffe and native yellow perch in laboratory studies

    USGS Publications Warehouse

    Savino, Jacqueline F.; Kolar, Cynthia S.

    1996-01-01

    The ruffe Gymnocephalus cernuus is a European percid that was accidently introduced in Duluth Harbor, Lake Superior. This nonindigenous species is closely related to yellow perch Perca flavescens, and because the two species have similar diets and habitat requirements, they are potential competitors. Laboratory studies in aquaria and pools were conducted to determine whether ruffe can compete with yellow perch for food. Ruffe had capture rates similar to those of yellow perch when food was unlimited. Ruffe spent more time than yellow perch over a feeding container before leaving it and searching again, and they also required less time to ingest (or handle) prey. However, the presence of yellow perch shortened the time ruffe spent over foraging areas when food was more limited. In addition, yellow perch were more active than ruffe, as indicated by their more frequent visits to a feeding container. Hence, the outcome of exploitative competition was not conclusive; ruffe appear to have the advantage in some behaviors, yellow perch in others. Ruffe were much more aggressive than yellow perch, and interference competition may be important in the interactions between these species. Our results indicate that ruffe might compete with native yellow perch.

  16. Domestication drive the changes of immune and digestive system of Eurasian perch (Perca fluviatilis)

    PubMed Central

    Chen, Xiaowen; Wang, Jun; Qian, Long; Gaughan, Sarah; Xiang, Wei; Ai, Tao; Fan, Zhenming; Wang, Chenghui

    2017-01-01

    Domestication has altered a variety of traits within the Eurasian perch (Perca fluviatilis), including phenotypic, physiological and behavioral traits of Eurasian perch (Perca fluviatilis). Little is known, however, about the genetic changes between domesticated and wild Eurasian perch. In this study, we assembled a high-quality de novo reference transcriptome and identified differentially expressed genes between wild and domesticated Eurasian perch. A total of 113,709 transcripts were assembled, and 58,380 transcripts were annotated. Transcriptomic comparison revealed 630 differentially expressed genes between domesticated and wild Eurasian perch. Within domesticated Eurasian perch there were 412 genes that were up-regulated including MHCI, MHCII, chia, ighm within immune system development. There were 218 genes including try1, ctrl, ctrb, cela3b, cpa1 and cpb1, which were down-regulated that were associated with digestive processes. Our results indicated domestication drives the changes of immune and digestive system of Eurasian perch. Our study not only provide valuable genetic resources for further studies in Eurasian perch, but also provide novel insights into the genetic basis of physiological changes in Eurasian perch during domestication process. PMID:28257494

  17. Domestication drive the changes of immune and digestive system of Eurasian perch (Perca fluviatilis).

    PubMed

    Chen, Xiaowen; Wang, Jun; Qian, Long; Gaughan, Sarah; Xiang, Wei; Ai, Tao; Fan, Zhenming; Wang, Chenghui

    2017-01-01

    Domestication has altered a variety of traits within the Eurasian perch (Perca fluviatilis), including phenotypic, physiological and behavioral traits of Eurasian perch (Perca fluviatilis). Little is known, however, about the genetic changes between domesticated and wild Eurasian perch. In this study, we assembled a high-quality de novo reference transcriptome and identified differentially expressed genes between wild and domesticated Eurasian perch. A total of 113,709 transcripts were assembled, and 58,380 transcripts were annotated. Transcriptomic comparison revealed 630 differentially expressed genes between domesticated and wild Eurasian perch. Within domesticated Eurasian perch there were 412 genes that were up-regulated including MHCI, MHCII, chia, ighm within immune system development. There were 218 genes including try1, ctrl, ctrb, cela3b, cpa1 and cpb1, which were down-regulated that were associated with digestive processes. Our results indicated domestication drives the changes of immune and digestive system of Eurasian perch. Our study not only provide valuable genetic resources for further studies in Eurasian perch, but also provide novel insights into the genetic basis of physiological changes in Eurasian perch during domestication process.

  18. Dynamics and Control of Three-Dimensional Perching Maneuver under Dynamic Stall Influence

    NASA Astrophysics Data System (ADS)

    Feroskhan, Mir Alikhan Bin Mohammad

    Perching is a type of aggressive maneuver performed by the class 'Aves' species to attain precision point landing with a generally short landing distance. Perching capability is desirable on unmanned aerial vehicles (UAVs) due to its efficient deceleration process that potentially expands the functionality and flight envelope of the aircraft. This dissertation extends the previous works on perching, which is mostly limited to two-dimensional (2D) cases, to its state-of-the-art threedimensional (3D) variety. This dissertation presents the aerodynamic modeling and optimization framework adopted to generate unprecedented variants of the 3D perching maneuver that include the sideslip perching trajectory, which ameliorates the existing 2D perching concept by eliminating the undesirable undershoot and reliance on gravity. The sideslip perching technique methodically utilizes the lateral and longitudinal drag mechanisms through consecutive phases of yawing and pitching-up motion. Since perching maneuver involves high rates of change in the angles of attack and large turn rates, introduction of three internal variables thus becomes necessary for addressing the influence of dynamic stall delay on the UAV's transient post-stall behavior. These variables are then integrated into a static nonlinear aerodynamic model, developed using empirical and analytical methods, and into an optimization framework that generates a trajectory of sideslip perching maneuver, acquiring over 70% velocity reduction. An impact study of the dynamic stall influence on the optimal perching trajectories suggests that consideration of dynamic stall delay is essential due to the significant discrepancies in the corresponding control inputs required. A comparative study between 2D and 3D perching is also conducted to examine the different drag mechanisms employed by 2D and 3D perching respectively. 3D perching is presented as a more efficient deceleration technique with respect to spatial costs and

  19. Performance evaluation of heat-stressed commercial broilers provided water-cooled floor perches.

    PubMed

    Reilly, W M; Koelkebeck, K W; Harrison, P C

    1991-08-01

    A study was conducted to determine whether water-cooled floor perches would be utilized by commercial broilers exposed to a constant hot ambient environment; and subsequently, whether utilization of these perches would improve performance beyond those provided uncooled floor perches. A total of 330 day-old commercial broiler chicks were randomly allocated to six pens (2.44 m2) in an environmentally controlled facility and maintained in a thermoneutral brooding environment for 16 days. Following this period, 240 birds were selected on a body weight basis and randomly assigned to the six pens. A perch constructed from steel pipe (2.44 m length, 5.0 cm diameter) was then placed diagonally on the litter covered floor of each pen. The birds were first exposed to a thermoneutral period (27.7 C), during which time cooling of the perches in three replicate pens was initiated by circulating tap water. The other three experimental pens received ambient perches. Ambient temperature was then raised to 32.6 C for the following 4 wk. The results of the present study showed that utilization of water-cooled perches by broilers was greater (P less than or equal to .01) than ambient perch utilization throughout the 32.6 C period. Average daily gain was greatest (P less than or equal to .01) for broilers exposed to cool perches. Additionally, they consume more feed (P less than or equal to .05), on a daily basis, than those given ambient perches during the heat-stress period. Broilers exposed to water-cooled perches also had a more efficient gain to feed ratio (P less than or equal to .01). At the completion of the study, final body weight and total body weight gain were greater (P less than or equal to .05) for broilers given water-cooled perches compared with those exposed to ambient perches. Total amount of feed consumed and total feed efficiency were only moderately affected (P less than or equal to .10) by perch treatments. These results indicated that water-cooled perches were

  20. Cool perch availability improves the performance and welfare status of broiler chickens in hot weather.

    PubMed

    Zhao, J P; Jiao, H C; Jiang, Y B; Song, Z G; Wang, X J; Lin, H

    2012-08-01

    A study was conducted to determine whether water-cooled perches would be preferred by commercial broilers exposed to a hot ambient environment, and subsequently, whether utilization of these perches would improve performance and the well-being of birds, beyond those provided by normal perches. Four hundred and thirty-two 14-d-old male chickens from a commercial fast-growing strain (Arbor Acres) were housed in the following conditions: 1) cool perches, 2) normal perches, and 3) control pens with no perches. The results showed that there was greater use of cool perches than normal perches for broiler chickens during summer (F1, 4=125, P=0.0004). Cool perches increased BW gain (F2, 6=5.44, P=0.0449) and breast (F2, 24=3.31, P=0.0539) and thigh muscle yields (F2, 24=6.29, P=0.0063), while decreasing abdominal fat deposition (F2, 24=7.57, P=0.0028), cooking loss (pectoralis major, F2, 24=3.30, P=0.0542; biceps femoris, F2, 24=3.42, P=0.0493), percentage of panting birds (F2, 6=102, P<0.0001), and scores of footpad (F2, 6=122, P<0.0001) and hock (F2, 6=68.2, P<0.0001) burn, and abdominal plumage condition (F2, 6=52.0, P=0.0002), particularly toward the end of the rearing period. In contrast, normal perches hardly affected growth performance, carcass composition, meat quality and behavioral patterns, and appeared to worsen the welfare status, including footpad and hock burns and abdominal plumage condition, due to a lower occupancy rate. Cool perches offer a thermoregulatory and performance advantage to broilers exposed to a hot environment and appear to be a management strategy for improving the production and well-being of commercial broilers.

  1. Perch compliance and experience affect destination choice of brown tree snakes (Boiga irregularis).

    PubMed

    Mauro, A Alexander; Jayne, C Bruce

    2016-04-01

    Arboreal animals often encounter branches with variable diameters that are highly correlated with stiffness, but how surface compliance affects the perch choice of animals is poorly understood. We used artificial branches to test the effects of different diameters and compliance on the choice between two destinations for twenty brown tree snakes as they bridged gaps. When both destinations were rigid, the diameters of the surfaces did not affect perch choice. However, with increased experience snakes developed a preference for a rigid, large-diameter perch compared to a compliant, small-diameter perch that collapsed under loads that were a small fraction of the weight of the snake. In hundreds of trials, with only one exception, the snakes proceeded to crawl entirely onto all rigid perches after first touching them, whereas the snakes commonly withdrew from the compliant perch even after touching it so lightly that it did not collapse. Hence, both tactile and visual cues appear to influence how these animals select a destination while crossing a gap. The preference for the rigid, large-diameter perch compared to the compliant, small-diameter perch developed mainly from short-term learning during three successive trials per testing session per individual. Furthermore, a preference for large diameters did not persist in the final treatment which used a rigid, large-diameter perch and a rigid, small-diameter perch. Hence, brown tree snakes appeared to be able to form short-term associations between the perch appearance and stiffness, the latter of which may have been determined via tactile sensory input.

  2. Cholangioma in white perch (Morone americana) from the Chesapeake Bay.

    PubMed

    Bunton, T E; Baksi, S M

    1988-01-01

    Cholangiomas found in two of 21 wild-caught white perch (Morone americana) from the Chesapeake Bay are described. The two fish were part of a study investigating a condition of abnormal hepatic copper storage in this species. The tumors were superficial, solitary masses consisting of cuboidal to columnar cells in tubuloglandular arrangement. Mild to marked peribiliary inflammation and fibrosis was seen also. Environmental pollution, the condition of abnormal copper storage, peribiliary fibrosis, and/or parasites may have contributed to the development of these tumors.

  3. The toxic effects of ammonia exposure on antioxidant and immune responses in Rockfish, Sebastes schlegelii during thermal stress.

    PubMed

    Kim, Shin-Hu; Kim, Jun-Hwan; Park, Myoung-Ae; Hwang, Seong Don; Kang, Ju-Chan

    2015-11-01

    Rockfish, Sebastes schlegelii (mean weight 14.53 ± 1.14 cm, and mean weight 38.36 ± 3.45 g) were exposed for 4 weeks (2 weeks and 4 weeks) with the different levels of ammonia in the concentrations of 0, 0.1, 0.5, 1.0mg/L at 19 and 24°C. The ammonia exposure induced significant alterations in antioxidant responses. The activities of SOD, CAT, and GST were considerably increased by the ammonia exposure depending on water temperature, whereas the GSH level was notably decreased after 2 and 4 weeks. In the stress indicators, the cortisol and HSP 70 were significantly elevated by the exposure to ammonia depending on water temperature. In innate immune responses, the phagocytosis and lysozyme activity were notably decreased by ammonia exposure depending on water temperature after 2 and 4 weeks. The results suggest that ammonia exposure depending on water temperature can induce the considerable alterations in antioxidant responses, stress, and immune inhibition.

  4. Toxic effects on bioaccumulation and hematological parameters of juvenile rockfish Sebastes schlegelii exposed to dietary lead (Pb) and ascorbic acid.

    PubMed

    Kim, Jun-Hwan; Kang, Ju-Chan

    2017-02-20

    Juvenile rockfish, Sebastes schlegelii (mean length 11.3 ± 1.2 cm, and mean weight 32.5 ± 4.1 g) were exposed for four weeks to dietary lead (Pb(2+)) at 0, 120, and 240 mg/L and ascorbic acid (AsA) at 100, 200, and 400 mg/L. The exposure concentrations and duration of significant Pb-induced accumulations in specific tissues of S. schlegelii were assessed. High levels of ascorbic acid significantly attenuated accumulations following exposure to dietary Pb. Dietary Pb exposure caused a significant increase in blood Pb concentrations, whereas red blood cell (RBC) count, hematocrit, and hemoglobin were significantly decreased. Notable changes were also observed in plasma calcium, magnesium, glucose, cholesterol, glutamic oxaloacetic transaminase (GOT), and glutamic pyruvate transaminase (GPT). The growth performance of S. schlegelii was significantly decreased. High doses AsA supplemention were effective in attenuating the changes brought about by dietary Pb exposure.

  5. The toxic effects on the stress and immune responses in juvenile rockfish, Sebastes schlegelii exposed to hexavalent chromium.

    PubMed

    Kim, Jun-Hwan; Kang, Ju-Chan

    2016-04-01

    Juvenile Sebastes schlegelii (mean length 13.7±1.7cm, and mean weight 55.6±4.8g) were exposed for 4 weeks with the different levels of dietary chromium (Cr(6+)) concentration (0, 30, 60, 120 and 200mg/L). The plasma cortisol and heat shock protein 70 was evaluated as stress indicators. Plasma cortisol was significantly increased in response to the dietary chromium exposure over 120mg/kg at 2 and 4 weeks. Heat shock protein 70 was also notably increased over 120mg/kg at 2 weeks and over 60mg/kg at 4 weeks. In the immune response, immunoglobulin M was considerably increased in the concentration of 240mg/kg at 2 weeks and over 120mg/kg at 4 weeks. Lysozyme activity was considerably induced by the dietary hexavalent chromium exposure. A significant increase in plasma lysozyme activity was observed at 240mg/kg after 2 weeks and over 60mg/kg after 4 weeks, kidney lysozyme was also increased over 120mg/kg at 2 and 4 weeks. The results demonstrate that dietary Cr exposure can induce a significant stress and immune stimulation.

  6. Morphological and molecular characterization of Pseudocohnilembus longisetus Thompson, 1965 from farmed black rockfish Sebastes schlegelii in Korea.

    PubMed

    Whang, Ilson; Kang, Hyun-Sil; Lee, Jehee

    2011-06-30

    The morphology, infraciliature, silverline system, and the small subunit ribosomal RNA (SSU rRNA) of the little-known marine scuticociliate Pseudocohnilembus longisetusThompson, 1965 from the diseased black rockfish Sebastes schlegelii in Korea were studied. This scuticociliate possessed the typical characteristics of the genus Pseudocohnilembus, but could be discriminated from Pseudocohnilembus hargisi, and Pseudocohnilembus persalinus in terms of the body size, shape, the number of somatic kineties and kinetids in somatic kinety 1, and the number/position of contractile vacuole pores. The SSU rRNA gene of P. longisetus was sequenced in order to gain a better understanding of appropriate phylogenetic classification. The SSU rRNA was 1754 bp and the sequence was deposited in GenBank under accession number FJ899594. The SSU rRNA gene sequences of P. longisetus had an identity of 98.1%, 96.8% and 95.3% with P. hargisi, P. persalinus, and Pseudocohnilembus marinus SSU rRNA sequences, respectively. Our population of P. longisetus belonged to the genus Pseudocohnilembus and was in an isolated position based on the SSU rRNA gene tree, which was consistent with the conclusions based on the morphological studies. However, further investigation is required to determine the pathogenicity of this species.

  7. Feasibility of partial replacement of fishmeal with proteins from different sources in diets of Korean rockfish ( Sebastes schlegeli)

    NASA Astrophysics Data System (ADS)

    Yan, Quangen; Zhu, Xiaoming; Yang, Yunxia; Han, Dong; Xie, Shouqi

    2014-12-01

    An 8-week feeding experiment was conducted in an indoor recirculation seawater system to investigate the effects of partial replacement of dietary fishmeal with proteins from five sources on the growth performance and feed utilization of Sebastes schlegeli. Six isonitrogenous and isoenergetic diets were formulated using fishmeal (FM, the control) as sole protein source, or proteins from five sources including poultry by-product meal (PBM), meat and bone meal (MBM), soybean meal (SBM), cottonseed meal (CSM) and canola meal (CNM). Fifteen percent of the crude protein provided by fish meal was replaced, respectively. The results showed that the differences in specific growth rate (SGR) and survival rate (SR) among fish fed PBM, MBM, SBM, CSM and whole FM diets were not significant. However, SGR and SR of fish fed CNM diet was significantly lower than that of other treatments. Feeding rate, feed conversion, nutrient retention showed similar patterns to that of growth. Fish fed CSM and CNM showed significantly lower apparent digestibility coefficient (ADC) of dry matter and gross energy than those fed others while fish fed CNM showed lower ADC of crude protein than those fed others ( P<0.05). These results suggested that it was feasible to substitute 15% dietary protein provided by fishmeal with PBM, MBM, SBM and CSM, respectively, but not with CNM as the replacement with CNM reduced fish growth and feed utilization.

  8. Scaling the sublethal effects of methylmercury to yellow perchs population dynamics using adverse outcome pathway framework

    USDA-ARS?s Scientific Manuscript database

    This study sought to evaluate the effects of environmentally relevant dietary MeHg exposures on adult female yellow perch (Perca flavescens) and zebrafish (Danio rerio) reproduction. Yellow perch were used in the study for their socioeconomic and ecological importance within the Great Lakes basin, a...

  9. Identification of gender in yellow perch Perca flavescens using external morphology

    USDA-ARS?s Scientific Manuscript database

    A non-lethal and rapid method for reliable identification of gender in yellow perch has been developed. On average, yellow perch females grow faster than males and undergo sexual maturity at an earlier age. Such size discrepancies in mixed culture situations pose difficulties with aquaculture produc...

  10. Was Lates Late? A Null Model for the Nile Perch Boom in Lake Victoria

    PubMed Central

    Downing, Andrea S.; Galic, Nika; Goudswaard, Kees P. C.; van Nes, Egbert H.; Scheffer, Marten; Witte, Frans; Mooij, Wolf M.

    2013-01-01

    Nile perch (Lates niloticus) suddenly invaded Lake Victoria between 1979 and 1987, 25 years after its introduction in the Ugandan side of the lake. Nile perch then replaced the native fish diversity and irreversibly altered the ecosystem and its role to lakeshore societies: it is now a prised export product that supports millions of livelihoods. The delay in the Nile perch boom led to a hunt for triggers of the sudden boom and generated several hypotheses regarding its growth at low abundances – all hypotheses having important implications for the management of Nile perch stocks. We use logistic growth as a parsimonious null model to predict when the Nile perch invasion should have been expected, given its growth rate, initial stock size and introduction year. We find the first exponential growth phase can explain the timing of the perch boom at the scale of Lake Victoria, suggesting that complex mechanisms are not necessary to explain the Nile perch invasion or its timing. However, the boom started in Kenya before Uganda, indicating perhaps that Allee effects act at smaller scales than that of the whole Lake. The Nile perch invasion of other lakes indicates that habitat differences may also have an effect on invasion success. Our results suggest there is probably no single management strategy applicable to the whole lake that would lead to both efficient and sustainable exploitation of its resources. PMID:24204684

  11. Was Lates late? A null model for the Nile perch boom in Lake Victoria.

    PubMed

    Downing, Andrea S; Galic, Nika; Goudswaard, Kees P C; van Nes, Egbert H; Scheffer, Marten; Witte, Frans; Mooij, Wolf M

    2013-01-01

    Nile perch (Lates niloticus) suddenly invaded Lake Victoria between 1979 and 1987, 25 years after its introduction in the Ugandan side of the lake. Nile perch then replaced the native fish diversity and irreversibly altered the ecosystem and its role to lakeshore societies: it is now a prised export product that supports millions of livelihoods. The delay in the Nile perch boom led to a hunt for triggers of the sudden boom and generated several hypotheses regarding its growth at low abundances--all hypotheses having important implications for the management of Nile perch stocks. We use logistic growth as a parsimonious null model to predict when the Nile perch invasion should have been expected, given its growth rate, initial stock size and introduction year. We find the first exponential growth phase can explain the timing of the perch boom at the scale of Lake Victoria, suggesting that complex mechanisms are not necessary to explain the Nile perch invasion or its timing. However, the boom started in Kenya before Uganda, indicating perhaps that Allee effects act at smaller scales than that of the whole Lake. The Nile perch invasion of other lakes indicates that habitat differences may also have an effect on invasion success. Our results suggest there is probably no single management strategy applicable to the whole lake that would lead to both efficient and sustainable exploitation of its resources.

  12. Complete Genome Sequence of a Giant Sea Perch Iridovirus in Kaohsiung, Taiwan

    PubMed Central

    Hong, Jiann-Ruey

    2016-01-01

    We report here the complete genome sequence of a megalocytivirus strain, GSIV-K1, isolated from a farmed giant sea perch (Lates calcarifer) in Kaohsiung, Taiwan. GSIV-K1 causes mortality in farmed marine fish, including giant sea perch and groupers. The genome sequence is nearly identical to the genome of the orange-spotted grouper iridovirus. PMID:27125488

  13. Complete Genome Sequence of a Giant Sea Perch Iridovirus in Kaohsiung, Taiwan.

    PubMed

    Wen, Chiu-Ming; Hong, Jiann-Ruey

    2016-04-28

    We report here the complete genome sequence of a megalocytivirus strain, GSIV-K1, isolated from a farmed giant sea perch (Lates calcarifer) in Kaohsiung, Taiwan. GSIV-K1 causes mortality in farmed marine fish, including giant sea perch and groupers. The genome sequence is nearly identical to the genome of the orange-spotted grouper iridovirus.

  14. Genome Sequence of a Ranavirus Isolated from Pike-Perch Sander lucioperca

    PubMed Central

    Holopainen, Riikka; Steckler, Natalie K.; Claytor, Sieara C.; Ariel, Ellen

    2016-01-01

    The pike-perch iridovirus (PPIV) was isolated in Finland from apparently healthy pike-perch fingerlings during routine disease surveillance. Our phylogenomic analysis revealed that PPIV is the first fish member of a clade of ranaviruses previously described from European and Chinese amphibians. PMID:27856591

  15. Anadromous alewives, Alosa pseudoharengus, as prey for white perch, Morone americana

    USGS Publications Warehouse

    Moring, J.R.; Mink, L.H.

    2002-01-01

    The reintroduction of anadromous alewives, Alosa pseudoharengus, to their historic habitats in the inland waters of the United States and Canada, has prompted concerns about possible interactions with a popular sport fish, white perch, Morone americana. Both species are now widely distributed in northeastern North America. Diets of white perch in Lake George, Maine, U.S.A., where alewives were absent, were monitored and compared with those of white perch populations that were sympatric with anadromous alewives in two coastal Maine lakes, Biscay Pond and North Pond. In the presence of introduced alewives, the diet of adult white perch became almost exclusively juvenile alewives by late summer in ponds where both species were present. White perch that were sympatric with alewives were more piscivorus than were Lake George white perch, which primarily consumed Cladocera. Not only were alewives the principal prey item in the diet of white perch in Biscay and North ponds, but adult alewives were largely cannibalistic by August. Thus, success of reintroducing anadromous alewives in waters containing white perch may be negatively impacted by predation as well as cannibalism.

  16. Comparative effects of constant versus fluctuating thermal regimens on yellow perch growth, feed conversion and survival

    USDA-ARS?s Scientific Manuscript database

    The effects of fluctuating or constant thermal regimens on growth, mortality, and feed conversion were determined for juvenile yellow perch (Perca flavescens). Yellow perch averaging 156mm total length and 43g body weight were held in replicate 288L circular tanks for 129 days under: 1) a diel therm...

  17. The effect of perch availability during pullet rearing and egg laying on the behavior of caged White Leghorn hens.

    PubMed

    Hester, P Y; Garner, J P; Enneking, S A; Cheng, H W; Einstein, M E

    2014-10-01

    Enriched cages, compared with conventional cages, allow egg laying strains of chickens to meet some behavioral needs, including a high motivation to perch. The objective of this study was to determine if perch availability during rearing affected perch use as adults and if perch presence affected eating and drinking in caged White Leghorn hens. Chickens were assigned to 14 cages each with and without 2 round metal perches from hatch to 16.9 wk of age. At 17 wk of age, pullets were assigned to laying cages consisting of 1 of 4 treatments. Treatment 1 chickens never had access to perches (controls). Treatment 2 chickens only had access to 2 round metal perches during the laying phase (17 to 71 wk of age). Treatment 3 chickens only had access to 2 round perches during the pullet phase (0 to 16.9 wk of age). Treatment 4 chickens had access to the perches during both the pullet and laying phase. Each treatment during the adult phase consisted of 9 cages with 9 birds/cage for a total of 36 cages. Automatic infrared cameras were used to monitor behavior of hens in each cage for a 24-h period at 19, 24, 29, 34, 39, 44, 49, 54, 59, 64, and 69 wk of age. Behavior was also recorded twice weekly by an observer in the room where the hens were housed during photophase from 25 to 68 wk of age. Behavioral data were analyzed using ANOVA with repeated measures and the MIXED model procedure. A greater proportion of hens without perches as pullets used the rear perch more during both photophase and scotophase than hens with prior pullet perching experience. Eating and drinking activities of caged adult Leghorns were not impaired by their prior experience to perches as pullets or by the presence of perches in laying cages. It is concluded that providing perches in cages to White Leghorns during pullet rearing did not facilitate use of perches as adults.

  18. Cooled perch effects on performance and well-being traits in caged White Leghorn hens.

    PubMed

    Hu, J Y; Hester, P Y; Makagon, M M; Vezzoli, G; Gates, R S; Xiong, Y J; Cheng, H W

    2016-12-01

    We assessed the effects of chilled water cooling perches on hen performance and physiological and behavioral parameters under "natural" high temperatures during the 2013 summer with a 4-hour acute heating episode. White Leghorns at 16 wk of age (N = 162) were randomly assigned to 18 cages (n = 9) arranged into 3 units. Each unit was assigned to one of the 3 treatments through 32 wk of age: 1) cooled perches, 2) air perches, and 3) no perches. Chilled water (10°C) was circulated through the cooled perches when cage ambient temperature exceeded 25°C. At the age of 27.6 wk, hens were subjected to a 4-hour acute heating episode of 33.3°C and plasma corticosterone was determined within 2 hours. Egg production was recorded daily. Feed intake and egg and shell quality were measured at 5-week intervals. Feather condition, foot health, adrenal and liver weights, plasma corticosterone, and heat shock protein 70 mRNA were determined at the end of the study at 32 wk of age. The proportion of hens per cage perching, feeding, drinking, panting, and wing spreading was evaluated over one d every 5 wks and on the d of acute heat stress. There were no treatment effects on the measured physiological and production traits except for nail length. Nails were shorter for cooled perch hens than control (P = 0.002) but not air perch hens. Panting and wing spread were observed only on the day of acute heat stress. The onset of both behaviors was delayed for cooled perch hens, and they perched more than air perch hens following acute heat stress (P = 0.001) and at the age 21.4 wk (P = 0.023). Cooled perch hens drank less than control (P = 0.019) but not air perch hens at the age 21.4 wk. These results indicate that thermally cooled perches reduced thermoregulatory behaviors during acute heat stress, but did not affect their performance and physiological parameters under the ambient temperature imposed during this study. Published by Oxford University Press on behalf of

  19. A modeling study of perched water phenomena in the vadose zone

    SciTech Connect

    Wu, Y.-S.; Ritchey, A. C.; Bodvarsson, G. S.

    1997-12-16

    The presence of perched water bodies in the vicinity of the potential repository at Yucca Mountain has many implications, and however, it may provide insight into moisture movement, flow pathways, or surface infiltration history of the mountain. The first implication is that percolation flux does not travel vertically through the unsaturated zone to the water table, but has been trapped, blocked or diverted laterally. As a result, non-uniform recharge rates are expected at the water table. Another concern is that perched zones may divert water around low-permeability zeolitic lenses underlying the potential repository horizon. By-passing of these units, which are thought to have substantial capacity to retard radionuclide transport, could have important implications for the capability of the geologic system to mitigate radionuclide releases to the environment. We have conducted a series of 3-D modeling simulations to investigate the perched water occurrences at the Yucca Mountain site, using a numerical code and available perched water data from six boreholes. A spatially varying surface infiltration map (Flint et al., 1996) is used to describe areally distributed net infiltration at the model land surface. Perched water data observed in the field were used to calibrate the model in terms of matrix and fracture permeabilities, capillary functions, and relative permeabilities of gas within the perched zones. Calibrated parameter values were within the range of field and laboratory measurements. The steady-state simulation results are in agreement with the observed perched water data in terms of water saturation and perched water locations. Furthermore, the results of a transient numerical pumping test conducted, using a 3-D submodel, matched water level data observed during field pumping tests. Perched water may occur where percolation flux exceeds the capacity of the geologic media to transmit flux in unsaturated zones. The conceptual model of water movement in the

  20. Effects of stocking density, light and perches on broiler growth.

    PubMed

    Velo, Ramón; Ceular, Angel

    2017-02-01

    The aim of this study was to determine the effect of stocking density, light intensity and light color on broiler growth. The experiment consisted of four 35-day phases during each of which 320 chickens were surveyed. The research was performed at stocking densities of four and six birds/m(2) . Illuminances of 15 and 30 lx were obtained through commercial lamps with 4000 K and 6000 K color temperatures. Lighting was used 17 h a day, between 06.00 and 23.00 hours (17 L:7 D). The results showed a decrease in body, carcass, breast and thighs weight (P < 0.05) with the increase in stocking density. Body weight decreased by 10.5% and carcass weight decreased by 9.4% at six birds/m(2) stocking density. Contrastingly, no differences were found for the tested light colors. Increasing illuminance from 15 to 30 lx caused a 1.9% decrease in body weight. The analysis of the effect of perches revealed that using perches significantly increased body (2.5%) and breast weight (11.8%). The interactions between light intensity or color and stocking density and between light intensity and light color were analyzed.

  1. Influence of nearshore structure on growth and diets of yellow perch (Perca flavescens) and white perch (Morone americana) in Mexico Bay, Lake Ontario

    USGS Publications Warehouse

    Danehy, Robert J.; Ringler, Neil H.; Gannon, John E.

    1991-01-01

    The growth diets of 969 yellow perch (Perca flavescens) and white perch (Morone americana) caught at 3.3 and 7.0 m depths were compared between two cobble/rubble shoals and two featureless sand sites in Mexico Bay, eastern Lake Ontario during 1981. The growth rate of both species was significantly greater for individuals captured over the cobble/rubble shoals. Females of both species were faster growing than the males, although only significantly so in the white perch. The seasonal diet and breadth of diet (H′) of yellow perch and white perch were not substantially different with respect to substrate type. Diet overlap between substrate types was also equivalent for each species. Benthic invertebrates, primarilyGammarus spp., were the major prey of both species at all sites. Alewife eggs were the most important item for the white perch in mid-summer, and alewife juveniles were important to both species in the fall. Differences in growth patterns between cobble/rubble shoals and sand sites illustrate a subtle effect of habitat on these species.

  2. The influence of sex and environmental temperature on the acute stress response of juvenile yellow perch Perca flavescens

    USDA-ARS?s Scientific Manuscript database

    Yellow perch are an ecologically and economically important fish in North America. At its peak, the Great Lakes yellow perch fishery constituted the largest inland capture fishery in North America. Even though wild populations have declined, consumer demand for yellow perch remains high, which has...

  3. Isolation and expression analysis of FTZ-F1 encoding gene of black rock fish ( Sebastes schlegelii)

    NASA Astrophysics Data System (ADS)

    Shafi, Muhammad; Wang, Yanan; Zhou, Xiaosu; Ma, Liman; Muhammad, Faiz; Qi, Jie; Zhang, Quanqi

    2013-03-01

    Sex related FTZ-F1 is a transcriptional factor regulating the expression of fushi tarazu (a member of the orphan nuclear receptors) gene. In this study, FTZ-F1 gene ( FTZ-F1) was isolated from the testis of black rockfish ( Sebastes schlegeli) by homology cloning. The full-length cDNA of S. schlegeli FTZ-F1 ( ssFTZ-F1) contained a 232bp 5' UTR, a 1449bp ORF encoding FTZ-F1 (482 amino acid residules in length) with an estimated molecular weight of 5.4kD and a 105bp 3' UTR. Sequence, tissue distribution and phylogenic analysis showed that ssFTZ-F1 belonged to FTZ group, holding highly conserved regions including I, II and III FTZ-F1 boxes and an AF-2 hexamer. Relatively high expression was observed at different larva stages. In juveniles (105 days old), the transcript of ssFTZ-F1 can be detected in all tissues and the abuncance of the gene transcript in testis, ovary, spleen and brain was higher than that in other tissues. In mature fish, the abundance of gene transcript was higher in testis, ovary, spleen and brain than that in liver (trace amount), and the gene was not transcribed in other tissues. The highest abundance of gene transcript was always observed in gonads of both juvenile and mature fish. In addition, the abundance of gene transcript in male tissues were higher than that in female tissue counterparts ( P<0.05).

  4. Does macroalgal vegetation cover influence post-settlement survival and recruitment potential of juvenile black rockfish Sebastes cheni?

    NASA Astrophysics Data System (ADS)

    Kamimura, Yasuhiro; Shoji, Jun

    2013-09-01

    Seasonal change in vegetation coverage affected cohort-specific mortality of post-settlement juvenile black rockfish Sebastes cheni in a temperate macroalgal bed. A total of 14 fish and environmental surveys were conducted at an interval of one to two weeks from February to May, 2008 in the central Seto Inland Sea, southwestern Japan. The birth date of S. cheni was estimated by use of the otolith daily rings and then fish were divided into 7 cohorts (A to F), each covering a 7-day birth date period. Cohort-specific growth coefficient (G, d-1) of juvenile S. cheni from 20 to 60 mm in total length (TL) ranged between 0.031 and 0.048 and mortality coefficient (M, d-1) between 0.038 and 0.081, with significant increases in both values as the season progressed. The ratio of G:M, which is a proxy of the recruitment potential, ranged between 0.59 and 0.99 and was lower in later cohorts. Water temperature increased from 10.9 °C in March to 18.2 °C in May and vegetation coverage (bulk volume of Sargassum spp., %: as an index of the function for predation refuge) decreased from 60% in March to 2% in May. The later cohorts of juvenile S. cheni had high growth and mortality rates related to high temperature and low vegetation coverage. Since the seasonal increase in M was greater than that of G, the recruitment potential of the later cohorts was lower than that of the earlier cohorts.

  5. The effects of temperature and water concentration on the otolith incorporation of barium and manganese in black rockfish Sebastes melanops.

    PubMed

    Miller, J A

    2009-07-01

    Observations of multiple years of geographic variation in [Ba:Ca](otolith) and [Mn:Ca](otolith) in black rockfish Sebastes melanops prompted this study to examine the effects of temperature and water concentration on the otolith incorporation of Ba and Mn in this wholly marine species. The replicated experiment design consisted of two water temperatures (7.4 and 13.0 degrees C) and four water concentrations of Ba:Ca and Mn:Ca. A positive, linear relationship between [Ba:Ca](water) and [Ba:Ca](otolith) was observed at both temperatures. A positive temperature effect was also observed with mean partition coefficients for Ba (D(Ba)) greater in the 13 degrees C than in the 7.4 degrees C treatments (mean = 0.061 and 0.048, respectively). There was no relationship between [Mn:Ca](water) and [Mn:Ca](otolith) although a negative temperature effect was observed. Mean partition coefficients for Mn (D(Mn)) were lower in the 13 degrees C than in the 7.4 degrees C treatments (mean = 0.027 and 0.036, respectively). The data presented support the assumption of a positive, linear relationship between water and otolith Metal:Ca concentrations for Ba:Ca but not for Mn:Ca. Thus, although indicative of residence in distinct water masses, observed variation in [Metal:Ca](otolith) may not reflect variation in water concentration and can be affected by temperature. Caution should be applied in the interpretation of geographic variation of [Mn:Ca](otolith) until the mechanisms regulating its incorporation are more fully understood.

  6. Molecular evidence for multiple paternity in a population of the Viviparous Tule Perch Hysterocarpus traski.

    PubMed

    Liu, Jin-Xian; Tatarenkov, Andrey; O'Rear, Teejay A; Moyle, Peter B; Avise, John C

    2013-03-01

    Population density might be an important variable in determining the degree of multiple paternity. In a previous study, a high level of multiple paternity was detected in the shiner perch Cymatogaster aggregata, a species with high population density and a high mate encounter rate. The tule perch Hysterocarpus traski is phylogenetically closely related to C. aggregata, but it has relatively lower population density, which may result in distinct patterns of multiple paternity in these 2 species. To test the hypothesis that mate encounter rate may affect the rate of successful mating, we used polymorphic microsatellite markers to identify multiple paternity in the progeny arrays of 12 pregnant females from a natural population of tule perch. Multiple paternity was detected in 11 (92%) of the 12 broods. The number of sires per brood ranged from 1 to 4 (mean 2.5) but with no correlation between sire number and brood size. Although the brood size of tule perch is considerably larger than that of shiner perch (40.7 vs. 12.9, respectively), the average number of sires per brood in tule perch is much lower than that in shiner perch (2.5 vs. 4.6, respectively). These results are consistent with the hypothesis that mate encounter rate is an important factor affecting multiple mating.

  7. Responses of Acilius sulcatus (Coleoptera: Dytiscidae) to chemical cues from perch (Perca fluviatilis).

    PubMed

    Åbjörnsson, Kajsa; Wagner, Bálint M A; Axelsson, Anna; Bjerselius, Rickard; Olsén, K Håkan

    1997-07-01

    In this study we tested the hypothesis that the presence of chemical stimuli from a hungry predator would initiate anti-predator responses, while stimuli from a satiated predator would not. We used chemical stimuli released from starved perch (Perca fluviatilis) and from satiated perch (predator). As prey we used adult Acilius sulcatus (Coleoptera: Dytiscidae). The reaction of the beetles to different predator conditions was tested during daytime. We also tested the reaction to starved perch during the night. A. sulcatus activity decreased when it was exposed to stimuli released from starved perch during daytime when visibility was poor, due to the presence of artificial vegetation. There was, however, no reaction to satiated perch under the same experimental conditions. These results indicate that A. sulcatus can discriminate between chemical cues from hungry and satiated fish predators. When visibility was good and the concentration of chemical cues was constant, the beetles did not react to starved perch in the daytime, but their activity decreased at night in response to stimuli released from starved perch. Visual as well as chemical cues seem to be important for detecting a potential predator. When visibility is good, beetles seem to rely on visual stimuli, while in darkness they seem to use chemical stimuli to detect the presence of predators.

  8. Intraspecific variation in gill morphology of juvenile Nile perch, Lates niloticus, in Lake Nabugabo, Uganda

    USGS Publications Warehouse

    Paterson, Jaclyn A.; Chapman, Lauren J.; Schofield, Pamela J.

    2010-01-01

    Several studies have demonstrated intraspecific variation in fish gill size that relates to variation in dissolved oxygen (DO) availability across habitats. In Lake Nabugabo, East Africa, ecological change over the past 12 years has coincided with a shift in the distribution of introduced Nile perch such that a larger proportion of the population now inhabits waters in or near wetland ecotones where DO is lower than in open waters of the lake. In this study, we compared gill size of juvenile Nile perch between wetland and exposed (open-water) habitats of Lake Nabugabo in 2007, as well as between Nile perch collected in 1996 and 2007. For Nile perch of Lake Nabugabo [<20 cm total length (TL)], there was a significant habitat effect on some gill traits. In general, fish from wetland habitats were characterized by a longer total gill filament length and average gill filament length than conspecifics from exposed habitats. Nile perch collected from wetland areas in 2007 had significantly larger gills (total gill filament length) than Nile perch collected in 1996, but there was no difference detected between Nile perch collected from exposed sites in 2007 and conspecifics collected in 1996.

  9. Food habits of stunted and non-stunted white perch (Morone americana)

    USGS Publications Warehouse

    Gosch, N.J.C.; Stittie, J.R.; Pope, K.L.

    2010-01-01

    We studied food habits of white perch (Morone americana) from two populations with different stable states (stunted [Branched Oak Lake, Nebraska] and nonstunted [Pawnee Lake, Nebraska]) to determine if change in food habits of white perch is likely to occur in situations where a stunted white perch population is altered to a nonstunted state and vice versa. Three approaches were used to quantitatively describe seasonal (spring = March-May, summer = June-August, autumn = September-November) diets of white perch - 1) frequency of occurrence, 2) percentage of composition by volume, and 3) mean stomach fullness. White perch diets were dominated by cladocerans and dipterans in both reservoirs during all seasons. Fish egg predation was similar between reservoirs, and white perch rarely consumed fishes in either the stunted or the non-stunted population. Shifting a white perch population between stunted and non-stunted states will likely cause little or no change in food habits; fish in both states will primarily consume invertebrates.

  10. A robin perches on a branch at KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A robin perches on a branch in the Merritt Island National Wildlife Refuge, which shares a boundary with the space center. Robins range throughout North America, from Alaska to Florida. Although considered a harbinger of spring, they do winter in northern states, frequenting cedar bogs and swamps. They also winter in Florida, where they often can be seen in flocks of hundreds near KSC and the wildlife refuge, which comprises 92,000 acres, ranging from hardwood hammocks and pine flatwoods to fresh-water impoundments, salt-water estuaries and brackish marshes. The diverse landscape provides habitat for more than 310 species of birds, 25 mammals, 117 fishes, and 65 amphibians and reptiles, including such endangered species as Southern bald eagles, wood storks, Florida scrub jays, Atlantic loggerhead and leatherback turtles, osprey, and nearly 5,000 alligators.

  11. A robin perches on a branch at KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A robin perches on a branch in the Merritt Island National Wildlife Refuge, which shares a boundary with the space center. Robins range throughout North America, from Alaska to Florida. Although considered a harbinger of spring, they do winter in northern states, frequenting cedar bogs and swamps. They also winter in Florida, where they often can be seen in flocks of hundreds near KSC and the wildlife refuge, which comprises 92,000 acres, ranging from hardwood hammocks and pine flatwoods to fresh-water impoundments, salt-water estuaries and brackish marshes. The diverse landscape provides habitat for more than 310 species of birds, 25 mammals, 117 fishes, and 65 amphibians and reptiles, including such endangered species as Southern bald eagles, wood storks, Florida scrub jays, Atlantic loggerhead and leatherback turtles, osprey, and nearly 5,000 alligators.

  12. A mockingbird perches on a limb at KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A mockingbird perches on a limb in the Merritt Island National Wildlife Refuge at Kennedy Space Center. The birds range from southern Canada south to the Caribbean and winter in the southern part of the range. Mockingbirds are very vocal, often imitating the sounds of other birds. Besides providing a winter home for the mockingbird, the refuge provides wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds. The 92,000- acre refuge is also habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles.

  13. Lake phosphorus loading form septic systems by seasonally perched groundwater

    USGS Publications Warehouse

    Gilliom, R.J.; Patmont, C.R.

    1983-01-01

    The movement of effluent phosphorus (P) from old septic systems by seasonally perched groundwater was investigated. A previous study indicated a correlation between P loadings and the presence of old homes. Water samples were taken from shallow wells installed 10 to 50 m downgradient from seven septic systems 20 to 40 years old. The equivalent volumetric fraction of each sample consisting of undiluted effluent was estimated from chloride concentration. A Monte Carlo analysis was used to account for the various sources of uncertainty. Movement of diluted septic effluent to the lake was common, but transport of more than 1% of effluent P through the soil was probable for only 4 of 26 samples. The greatest apparent P movement was associated with persistently saturated conditions.

  14. Genetic diversity of perch rhabdoviruses isolates based on the nucleoprotein and glycoprotein genes.

    PubMed

    Talbi, Chiraz; Cabon, Joelle; Baud, Marine; Bourjaily, Maya; de Boisséson, Claire; Castric, Jeannette; Bigarré, Laurent

    2011-12-01

    Despite the increasing impact of rhabdoviruses in European percid farming, the diversity of the viral populations is still poorly investigated. To address this issue, we sequenced the partial nucleoprotein (N) and complete glycoprotein (G) genes of nine rhabdoviruses isolated from perch (Perca fluviatilis) between 1999 and 2010, mostly from France, and analyzed six of them by immunofluorescence antibody test (IFAT). Using two rabbit antisera raised against either the reference perch rhabdovirus (PRhV) isolated in 1980 or the perch isolate R6146, two serogroups were distinguished. Meanwhile, based on partial N and complete G gene analysis, perch rhabdoviruses were divided into four genogroups, A-B-D and E, with a maximum of 32.9% divergence (G gene) between isolates. A comparison of the G amino acid sequences of isolates from the two identified serogroups revealed several variable regions that might account for antigenic differences. Comparative analysis of perch isolates with other rhabdoviruses isolated from black bass, pike-perch and pike showed some strong phylogenetic relationships, suggesting cross-host transmission. Similarly, striking genetic similarities were shown between perch rhabdoviruses and isolates from other European countries and various ecological niches, most likely reflecting the circulation of viruses through fish trade as well as putative transfers from marine to freshwater fish. Phylogenetic relationships of the newly characterized viruses were also determined within the family Rhabdoviridae. The analysis revealed a genetic cluster containing only fish viruses, including all rhabdoviruses from perch, as well as siniperca chuatsi rhabdovirus (SCRV) and eel virus X (EVEX). This cluster was distinct from the one represented by spring viraemia of carp vesiculovirus (SVCV), pike fry rhabdovirus (PFRV) and mammalian vesiculoviruses. The new genetic data provided in the present study shed light on the diversity of rhabdoviruses infecting perch in

  15. Reproductive health of yellow perch Perca flavescens in selected tributaries of the Chesapeake Bay.

    PubMed

    Blazer, Vicki S; Pinkney, Alfred E; Jenkins, Jill A; Iwanowicz, Luke R; Minkkinen, Steven; Draugelis-Dale, Rassa O; Uphoff, James H

    2013-03-01

    Reduced recruitment of yellow perch has been noted for a number of years in certain urbanized watersheds (South and Severn Rivers) of the Chesapeake Bay. Other rapidly developing watersheds such as Mattawoman Creek are more recently showing evidence of reduced recruitment of anadromous fishes. In this study, we used a battery of biomarkers to better document the reproductive health of adult yellow perch collected during spring spawning in 2007-2009. Perch were collected in the South and Severn Rivers, Mattawoman Creek and the less developed Choptank and Allen's Fresh watersheds for comparison. Gonadosomatic indices, plasma reproductive hormone concentrations, plasma vitellogenin concentrations and gonad histology were evaluated in mature perch of both sexes. In addition, sperm quantity (cell counts) and quality (total and progressive motility, spermatogenic stage and DNA integrity), were measured in male perch. Many of these biomarkers varied annually and spatially, with some interesting statistical results and trends. Male perch from the Choptank and Allen's Fresh had generally higher sperm counts. In 2008 counts were significantly lower in the perch from the Severn when compared to other sites. The major microscopic gonadal abnormality in males was the proliferation of putative Leydig cells, observed in testes from Severn and less commonly, Mattawoman Creek perch. Observations that could significantly impact egg viability were an apparent lack of final maturation, abnormal yolk and thin, irregular zona pellucida. These were observed primarily in ovaries from Severn, South and less commonly Mattawoman Creek perch. The potential association of these observations with urbanization, impervious surface and chemical contaminants is discussed. Published by Elsevier B.V.

  16. Perched-Water Analysis Related to Deep Vadose Zone Contaminant Transport and Impact to Groundwater

    SciTech Connect

    Oostrom, Martinus; Truex, Michael J.; Carroll, KC; Chronister, Glen B.

    2013-11-15

    Perched-water conditions have been observed in the vadose zone above a fine-grained zone that is located just a few meters above the water table beneath the B-complex at the Hanford Site. The perched water, containing elevated concentrations of uranium and technetium-99, is important to consider in evaluating the future flux of contaminated water into the groundwater. A study was conducted to examine the perched-water conditions and quantitatively evaluate 1) factors that control perching behavior, 2) contaminant flux toward groundwater, and, 3) associated groundwater impact. Based on the current vertical transport pathways and large areal extent of the perched system, the evaluation was conducted using a one-dimensional (1-D) analysis. Steady-state scoping calculations showed that the perching-layer hydraulic conductivity is likely to be up to two orders of magnitude less than the base case value obtained from Hanford site literature. Numerical flow and transport simulations provided both steady-state and transient system estimates of water and contaminant behavior and were used to further refine the range of conditions consistent with current observations of perched water height and to provide estimates of future water and contaminant flux to groundwater. With a recharge rate of 6 cm/yr, representative of current disturbed surface conditions, contaminant flux from the perched water occurs over a time interval of tens of years. However, if the recharge rate is 0.35 cm/yr, representative of returning recharge to pre-Hanford Site levels, the contaminant flux into the groundwater is spread over hundreds of years. It was also demonstrated that removal of perched water by pumping would reduce the flux of water (and associated contaminants) to the groundwater, thereby impacting the long-term rate of contaminant movement to the groundwater.

  17. Perched Soil Zone (PSZ) Aquifer Package for MODFLOW-2005

    NASA Astrophysics Data System (ADS)

    Henson, W.; Niswonger, R. G.

    2010-12-01

    An increasing number of investigators are looking at innovative ways to use precipitation data to calculate recharge to aquifer systems. Typically, simulation models are used to partition precipitation into evapotranspiration, runoff and recharge. Currently, the groundwater flow model, MODFLOW-2005, does not simulate dynamic near-surface hydrologic processes such as, infiltration, hortonian or dunnian runoff, return flow, or the effects of impervious surfaces on runoff. The Perched Soil-Zone package (PSZ) for MODFLOW-2005 is being developed to address these major components of hillslope hydrology for simulating watershed processes in the context of basin-scale groundwater flow modeling. This package extends MODFLOW-2005 capabilities to simulate soil zone processes in short time steps that are integrated to the much longer daily or weekly timesteps typically used in MODFLOW-2005. A perched aquifer often develops in the soil zone during periods of heavy rainfall, delivering interflow to channels in a watershed. The soil zone is the upper most region of the vadose zone where plant and soil processes enhance storage and permeability, providing a fast pathway for water and solutes to streams. The soil zone connects the watershed surface to the deeper unsaturated, and saturated zones. Modeling of soil zone processes has been used to gain understanding of watershed hydrologic processes. The PSZ package can use available data at finer time increments to ensure precipitation is properly distributed between infiltration and runoff. This physically based partitioning of precipitation allows for a more robust estimation of recharge. The PSZ package is intended to be used in basin scale MODFLOW-2005 simulations for efficiently simulating watershed hydrologic processes, especially those processes that partition rainfall into evapotranspiration, runoff, and recharge.

  18. The effect of perch access during pullet rearing and egg laying on physiological measurements of stress in 71-week-old White Leghorns

    USDA-ARS?s Scientific Manuscript database

    Egg laying strains of chickens have a strong motivation to perch. Providing caged chickens with perches allows them to perform their natural perching instinct and also improves their musculoskeletal health due to exercise. Little is known about the effect of perch access by hens on physiological mea...

  19. Pesticide residues and heavy metals in Lake Victoria Nile perch, Lates niloticus, belly flap oil.

    PubMed

    Ogwok, P; Muyonga, J H; Sserunjogi, M L

    2009-05-01

    Oil was extracted from the belly flaps of varied sizes of Nile perch caught from Lake Victoria (Uganda). The oil was analyzed for pesticide residues and heavy metals. Total residual concentration of dichlorodiphenyltrichloroethane, endosulfan, hexachlorocyclohexane, hexachlorobenzene, heptachlor, chlordane, endrin, aldrin and chlorofenvinphos increased significantly (p < 0.05) with fish size. Mercury and lead were detected in most samples while arsenic and cadmium were below detection limits. Nile perch may, therefore, accumulate significant amount of chemical contaminants. Levels of contaminants in Nile perch oil were, in general, within limits considered acceptable by the stringent German Food Law for human consumption.

  20. Reproductive health of yellow perch, Perca flavescens, in Chesapeake Bay Tributaries

    USGS Publications Warehouse

    Blazer, Vicki; Pinkney, A.E.; Uphoff, James H.

    2013-01-01

    Yellow perch live in creeks, rivers, ponds, lakes, and estuaries across the central and eastern United States and Canada. In Chesapeake Bay, they tolerate salinities up to one-third that of seawater. The adults reside in the brackish waters of the bay’s tributaries and migrate upstream to spawn. Yellow perch are eagerly sought by recreational fishermen for their excellent taste and, because their late winter spawning runs are the earliest of the year, they are regarded as a harbinger of spring. Yellow perch also support a small but valuable, tightly regulated commercial fishery in the part of Chesapeake Bay that lies in Maryland.

  1. Mercury accumulation in yellow perch in Wisconsin seepage lakes: Relation to lake characteristics

    USGS Publications Warehouse

    Cope, W.G.; Wiener, J.G.; Rada, R.G.

    1990-01-01

    We studied relations between lacustrine characteristics and the total mercury (Hg) content of calendar age- 2 yellow perch (Perca flavescens ) in 10 seepage lakes in north-central Wisconsin. Mean concentrations and burdens (masses) of Hg in whole perch varied widely among lakes, were negatively correlated with lake pH and were positively correlated with total Hg concentration in surficial profundal sediment. Approximately 80 to 90% of the variation in Hg concentration and burden in whole perch was explained with multiple regressions containing two independent variables: either lake pH or alkalinity, and Hg concentration in surficial sediment. The mean concentration of Hg in axial muscle tissue of age-5 walleyes (Stizostedion vitreum vitreum ) from five of the study lakes was highly correlated with the mean concentration in whole age-2 perch in the same lakes.

  2. Characterization and Extraction of Uranium Contamination Perched within the Deep Vadose Zone at the Hanford Site, Washington State

    NASA Astrophysics Data System (ADS)

    Williams, B. A.; Rohay, V. J.; Benecke, M. W.; Chronister, G. B.; Doornbos, M. H.; Morse, J.

    2012-12-01

    A highly contaminated perched water zone has been discovered in the deep vadose zone above the unconfined aquifer during drilling of wells to characterize groundwater contamination within the 200 East Area of the U.S. Department of Energy's Hanford Site in southeast Washington. The perched water, which contains nitrate, uranium, and technetium-99 at concentrations that have exceeded 100,000 μg/L, 70,000 μg/L, and 45,000 pCi/L respectively, is providing contamination to the underlying unconfined aquifer. A perched zone extraction well has been installed and is successfully recovering the contaminated perched water as an early remedial measure to reduce impacts to the unconfined aquifer. The integration and interpretation of various borehole hydrogeologic, geochemical, and geophysical data sets obtained during drilling facilitated the delineation of the perching horizon and determination of the nature and extent of the perched contamination. Integration of the borehole geologic and geophysical logs defined the structural elevation and thickness of the perching low permeability silt interval. Borehole geophysical moisture logs, gamma logs, and sample data allowed detailed determination of the elevation and thickness of the oversaturated zone above the perching horizon, and the extent and magnitude of the radiological uranium contamination within the perching interval. Together, these data sets resolved the nature of the perching horizon and the location and extent of the contaminated perched water within the perching zone, allowing an estimation of remaining contaminant extent. The resulting conceptual model indicates that the contaminated perched water is contained within a localized sand lens deposited in a structural low on top of a semi-regional low-permeability silt layer. The top of the sand lens is approximately 72 m (235 ft) below ground surface; the maximum thickness of the sand lens is approximately 3 m (10 ft). The lateral and vertical extent of the

  3. Susceptibility of Koi and Yellow Perch to infectious hematopoietic necrosis virus by experimental exposure

    USGS Publications Warehouse

    Palmer, Alexander D.; Emmenegger, Eveline J.

    2014-01-01

    Infectious hematopoietic necrosis virus (IHNV) is a novirhabdoviral pathogen that originated in western North America among anadromous Pacific salmonids. Severe disease epidemics in the late 1970s resulting from IHNV's invasion into farmed Rainbow Trout Oncorhynchus mykiss in North America, Asia, and Europe emphasized IHNV's ability to adapt to new hosts under varying rearing conditions. Yellow Perch Perca flavescens and Koi Carp Cyprinus carpio (hereafter, “Koi”) are aquaculture-reared fish that are highly valued in sport fisheries and the ornamental fish trade, respectively, but it is unknown whether these fish species are vulnerable to IHNV infection. In this study, we exposed Yellow Perch, Koi, and steelhead (anadromous Rainbow Trout) to IHNV by intraperitoneal injection (106 PFU/fish) and by immersion (5.7×105 PFU/mL) for 7 h, and monitored fish for 28 d. The extended immersion exposure and high virus concentrations used in the challenges were to determine if the tested fish had any level of susceptibility. After experimental exposure, Yellow Perch and Koi experienced low mortality (35%). Virus was found in dead fish of all species tested and in surviving Yellow Perch by plaque assay and quantitative reverse transcription polymerase chain reaction (qPCR), with a higher prevalence in Yellow Perch than Koi. Infectious virus was also detected in Yellow Perch out to 5 d after bath challenge. These findings indicate that Yellow Perch and Koi are highly resistant to IHNV disease under the conditions tested, but Yellow Perch are susceptible to infection and may serve as possible virus carriers.

  4. Susceptibility of Koi and Yellow Perch to infectious hematopoietic necrosis virus by experimental exposure.

    PubMed

    Palmer, Alexander D; Emmenegger, Eveline J

    2014-06-01

    Infectious hematopoietic necrosis virus (IHNV) is a novirhabdoviral pathogen that originated in western North America among anadromous Pacific salmonids. Severe disease epidemics in the late 1970s resulting from IHNV's invasion into farmed Rainbow Trout Oncorhynchus mykiss in North America, Asia, and Europe emphasized IHNV's ability to adapt to new hosts under varying rearing conditions. Yellow Perch Perca flavescens and Koi Carp Cyprinus carpio (hereafter, "Koi") are aquaculture-reared fish that are highly valued in sport fisheries and the ornamental fish trade, respectively, but it is unknown whether these fish species are vulnerable to IHNV infection. In this study, we exposed Yellow Perch, Koi, and steelhead (anadromous Rainbow Trout) to IHNV by intraperitoneal injection (10(6) PFU/fish) and by immersion (5.7×10(5) PFU/mL) for 7 h, and monitored fish for 28 d. The extended immersion exposure and high virus concentrations used in the challenges were to determine if the tested fish had any level of susceptibility. After experimental exposure, Yellow Perch and Koi experienced low mortality (<6%) compared with steelhead (>35%). Virus was found in dead fish of all species tested and in surviving Yellow Perch by plaque assay and quantitative reverse transcription polymerase chain reaction (qPCR), with a higher prevalence in Yellow Perch than Koi. Infectious virus was also detected in Yellow Perch out to 5 d after bath challenge. These findings indicate that Yellow Perch and Koi are highly resistant to IHNV disease under the conditions tested, but Yellow Perch are susceptible to infection and may serve as possible virus carriers.

  5. Soft Perches in an Aviary System Reduce Incidence of Keel Bone Damage in Laying Hens

    PubMed Central

    Stratmann, Ariane; Fröhlich, Ernst K. F.; Harlander-Matauschek, Alexandra; Schrader, Lars; Toscano, Michael J.; Würbel, Hanno; Gebhardt-Henrich, Sabine G.

    2015-01-01

    Keel bone fractures and deviations are one of the major welfare and health issues in commercial laying hens. In non-cage housing systems like aviaries, falls and collisions with perches and other parts of the housing system are assumed to be one of the main causes for the high incidence of keel bone damage. The objectives of this study were to investigate the effectiveness of a soft perch material to reduce keel bone fractures and deviations in white (Dekalb White) and brown laying hens (ISA Brown) kept in an aviary system under commercial conditions. In half of 20 pens, all hard, metal perches were covered with a soft polyurethane material. Palpation of 20 hens per pen was conducted at 18, 21, 23, 30, 38, 44 and 64 weeks of age. Production data including egg laying rate, floor eggs, mortality and feed consumption were collected over the whole laying period. Feather condition and body mass was assessed twice per laying period. The results revealed that pens with soft perches had a reduced number of keel bone fractures and deviations. Also, an interaction between hybrid and age indicated that the ISA hybrid had more fractured keel bones and fewer non-damaged keel bones compared with the DW hybrid at 18 weeks of age, a response that was reversed at the end of the experiment. This is the first study providing evidence for the effectiveness of a soft perch material within a commercial setting. Due to its compressible material soft perches are likely to absorb kinetic energy occurring during collisions and increase the spread of pressure on the keel bone during perching, providing a mechanism to reduce keel bone fractures and deviations, respectively. In combination with genetic selection for more resilient bones and new housing design, perch material is a promising tool to reduce keel bone damage in commercial systems. PMID:25811980

  6. Investigation of groundwater recirculation for the removal of RDX from the Pantex Plant perched aquifer

    SciTech Connect

    Woods, A.L.; Barnes, D.L.; Boles, K.M.; Charbeneau, R.J.; Black, S.; Rainwater, K.

    1998-07-01

    The Pantex Plant near Amarillo, Texas, is a US Department of Energy (DOE) facility that has been in operation since 1942. Past and present operations at Pantex include the creation of chemical high explosives components for nuclear weapons and assembly and disassembly of nuclear weapons. The Pantex Plant is underlain by the Ogallala aquifer, which in this area, consists of the main water-bearing unit and a perched water zone. These are separated by a fine-grained zone of low permeability. Multiple contaminant plumes containing high explosive (HE) compounds have been detected in the perched aquifer beneath the plant. The occurrence of these contaminants is the result of past waste disposal practices at the facility. RDX is an HE compound, which has been detected in the groundwater of the perched aquifer at significant concentrations. A pilot-scale, dual-phase extraction treatment system has been installed at one location at the plant, east of Zone 12, to test the effectiveness of such a system on the removal of these contaminants from the subsurface. A tracer test using a conservative tracer, bromide (Br), was conducted at the treatment site in 1996. In addition to the bromide, RDX and water elevations in the aquifer were monitored. Using data from the tracer test and other relevant data from the investigations at Pantex, flow and contaminant transport in the perched aquifer were simulated with groundwater models. The flow was modeled using MODFLOW and the transport of contaminants in the aqueous phase was modeled using MT3D. Modeling the perched aquifer had been conducted to characterize the flow in the perched aquifer; estimate RDX retardation in the perched aquifer; and evaluate the use of groundwater re-circulation to enhance the extraction of RDX from the perched aquifer.

  7. Nitrate-nitrogen concentrations in the perched ground water under seepage-irrigated potato cropping systems.

    PubMed

    Munoz-Arboleda, F; Mylavarapu, R; Hutchinson, C; Portier, K

    2008-01-01

    Excessive nitrogen rates for potato production in northeast Florida have been declared as a potential source of nitrate pollution in the St. Johns River watershed. This 3-yr study examined the effect of N rates (0, 168, and 280 kg ha(-1)) split between planting and 40 d after planting on the NO(3)-N concentration in the perched ground water under potato (Solanum tuberosum cv. Atlantic) in rotation with sorghum sudan grass hybrid (Sorghum vulgare x Sorghum vulgare var. sudanese, cv. SX17), cowpea (Vigna unguiculata cv. Iron Clay), and greenbean (Phaseolus vulgare cv. Espada). Soil solution from the root zone and water from the perched ground water under potato were sampled periodically using lysimeters and wells, respectively. Fertilization at planting increased the NO(3)-N concentration in the perched ground water, but no effect of the legumes in rotation with potatoes on nitrate leaching was detected. Fertilization of green bean increased NO(3)-N concentration in the perched ground water under potato planted in the following season. The NO(3)-N concentration in the soil solution within the potato root zone followed a similar pattern to that of the perched ground water but with higher initial values. The NO(3)-N concentration in the perched ground water was proportional to the rainfall magnitude after potato planting. A significant increase in NO(3)-N concentration in the perched ground water under cowpea planted in summer after potato was detected for the side-dressing of 168 kg ha(-1) N applied to potato 40 d after planting but not at the 56 kg ha(-1) N side-dress. Elevation in NO(3)-N concentration in the perched ground water under sorghum was not significant, supporting its use as an effective N catch crop.

  8. Growth and potential yield of perch (Perca spp.) in selected areas of Lake Baikal and the Laurentian Great Lakes

    USGS Publications Warehouse

    O'Gorman, Robert; Bronte, Charles R.; Hatcher, Charles O.; Pronin, Nikolai M.; Sokolnikov, Yury

    1998-01-01

    We compared growth, mortality, and potential yield of Eurasian perch (Perca fluviatilis) from Chivirkui Bay in Lake Baikal with that of yellow perch (P. flavescens) from three areas of the Laurentian Great Lakes --Chequamegon Bay in Lake Superior, northeastern Lake Ontario, and southwestern Lake Erie. Graded mesh gill nets were fished in August to sample perch in lakes Baikal (1993), Ontario (1985-93), and Erie (1994). Bottom trawls were fished in July-August to sample perch in Lake Superior (1973-93). Adult yellow perch from the Laurentian Great Lakes were heavier at most lengths than adult Eurasian perch from Lake Baikal. The increase in body weight per unit increase in length was greatest in Lake Erie. Total annual mortality of perch was low in Lake Baikal (0.31), intermediate in lakes Superior (0.41) and Ontario (0.54), and high in Lake Erie (0.66). Annual fishing mortality (u) for perch in Lake Baikal was 60%-70% lower than that for perch in the Great Lakes. At ages 1-3, perch in Lake Erie were longer than those in lakes Baikal, Superior, and Ontario but at ages 4-9 perch in Lake Baikal were longer than those in the other lakes. Although Eurasian perch in Lake Baikal were longer at age 4 and older, growth in length, as measured by the Brody growth coefficient, K, was lower there than in the other lakes and was similar to that in Lake Superior; yellow perch in Lake Erie grew the fastest. Yield-per-recruit was lowest in Lake Erie and highest in Lake Superior. Potential yield was influenced by growth rates and fishing mortality.

  9. Fish community dynamics in northeastern Lake Ontario with emphasis on the growth and reproductive success of yellow perch (Perca flavescens) and white perch (Morone americana), 1978 to1997

    USGS Publications Warehouse

    O'Gorman, Robert; Burnett, John A.D.

    2001-01-01

    Fishes were assessed in Guffin, Chaumount, and Black River bays in northeastern Lake Ontario with a 7.9-m (headrope) bottom trawl during late September and early October, 1978 to 1997. Fish density declined in the early 1990s with sharp declines in abundance of spottail shiner (Notropis hudsonius), trout-perch (Percopsis omiscomaycus), and johnny darter (Etheostoma nigrum) occurring in 1993 to 1995. Rising numbers of piscivores, walleye (Stizostedion vitreum) and double-crested cormorant (Phalacrocorax auritus), increased predation pressure, presumably acting in concert with oligotrophication to lower fish density, particularly after 1991 when large numbers of adult alewife (Alosa pseudoharengus) no longer migrated to the northeast basin in spring. Annual mortality of yellow perch (Perca flavescens) from age 2 to 5 rose from 33% in 1980–83 to 65% in 1992–95 and was positively related to piscivore numbers (P = 0.01, r = 0.96, n = 5). Annual mortality of yellow perch from age 0 to 2 also peaked in 1992–95. Abundance of yellow perch YOY in fall varied 40 fold and was not related to water warming in spring (P = 0.45, r = −0.19, n = 18) but was negatively related to the abundance of adult alewives in spring (P = 0.04, r = −0.49, n = 18). Although yellow perch produced moderate to strong year classes each year during 1991–95, stock size failed to increase because of rapidly accelerating mortality. Fully 85% of the variation in mean length of yellow perch YOY was explained by a multiple regression model which included YOY abundance, mean total phosphorus, and cumulative degree days > 13.5°C (P < 0.01, n = 15). Abundance of white perch (Morone americana) YOY varied nearly 200 fold and was not related to water warming or spring alewife abundance (P > 0.15). Variation in mean length of white perch YOY was related to cumulative degree days > 15°C (P < 0.01, r = 0.69).

  10. Impact of impingement on the Hudson River white perch population. Final report

    SciTech Connect

    Barnthouse, L.W.; Van Winkle, W.; Kirk, B.L.; Vaughan, D.S.

    1982-02-01

    This report summarizes a series of analyses of the magnitude and biological significance of the impingement of white perch at the Indian Point Nuclear Generating Station and other Hudson River power plants. Included in these analyses were evaluations of: (1) two independent lines of evidence relating to the magnitude of impingement impacts on the Hudson River white perch population; (2) the additional impact caused by entrainment of white perch; (3) data relating to density-dependent growth among young-of-the-year white perch; (4) the feasibility of performing population-level analyses of impingement impacts on the white perch populations of Chesapeake Bay and the Delaware River; and (5) the feasibility of using simple food chain and food web models to evaluate community-level effects of impingement and entrainment. Estimated reductions in the abundances of the 1974 and 1975 white perch year classes, caused by impingement and entrainment, were high enough that the possibility of adverse long-term effects cannot be excluded.

  11. A Southern Bald Eagle perches on a pole at KSC.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A Southern Bald Eagle perched on top of a utility pole searches the area. About a dozen bald eagles live in the Merritt Island National Wildlife Refuge, which shares a boundary with Kennedy Space Center. The Southern Bald Eagle ranges throughout Florida and along the coasts of California, Texas, Louisiana, and the south Atlantic states. Bald Eagles are listed as endangered in the U.S., except in five states where they are listed as threatened. The number of nesting pairs of the southern race once numbered several thousand; recent estimates are only 350-375. Most of the southern race nest in Florida. Eagles arrive at KSC during late summer and leave for the north in late spring. They move to nest sites in October and November and lay one to three eggs. The young fledge from February to April. The Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  12. A Southern Bald Eagle perches on a pole at KSC.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A Southern Bald Eagle perches on top of a utility pole at Kennedy Space Center. About a dozen bald eagles live in the Merritt Island National Wildlife Refuge, which shares a boundary with Kennedy Space Center. The Southern Bald Eagle ranges throughout Florida and along the coasts of California, Texas, Louisiana, and the south Atlantic states. Bald Eagles are listed as endangered in the U.S., except in five states where they are listed as threatened. The number of nesting pairs of the southern race once numbered several thousand; recent estimates are only 350-375. Most of the southern race nest in Florida. Eagles arrive at KSC during late summer and leave for the north in late spring. They move to nest sites in October and November and lay one to three eggs. The young fledge from February to April. The Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  13. Warming alters the body shape of European perch Perca fluviatilis.

    PubMed

    Rowiński, P K; Mateos-Gonzalez, F; Sandblom, E; Jutfelt, F; Ekström, A; Sundström, L F

    2015-11-01

    The consequences of elevated temperature on body shape were investigated by comparing European perch Perca fluviatilis from the Forsmark area of the Baltic Sea to P. fluviatilis from a nearby Biotest enclosure. The Biotest is a man-made enclosure within the Baltic Sea that has received warm water from a nuclear power plant since 1980, resulting in temperatures that are elevated 5-10 °C relative to the surrounding Baltic Sea. Sampled fish ranged from young-of-the-year to 14 years. Geometric morphometrics and multivariate statistical analysis revealed significant morphological differences between individuals of P. fluviatilis from these two habitats. Most importantly, relative shape changed with size, with small individuals of P. fluviatilis from Biotest being characterized by a deeper body shape and a larger caudal peduncle than the smaller Baltic individuals. In large specimens, smaller differences were found with Biotest individuals being more slender than Baltic individuals. These results show that, in order to have a full understanding of the biological effects of elevated temperatures, studies that cover the entire size range of organisms will be important. Apart from the direct influence of temperature on growth rate and body shape, other ecological factors affected by temperature are discussed as possible contributors to the observed differences between the two populations. © 2015 The Fisheries Society of the British Isles.

  14. Dynamics of a yellow perch population in western Lake Superior

    USGS Publications Warehouse

    Bronte, Charles R.; Selgeby, James H.; Swedberg, Donald V.

    1993-01-01

    Yellow perch Perca flavescens were sampled annually in 1973–1988 with bottom trawls in Chequamegon Bay, Lake Superior. Biomass averaged l.6 kg/hectare. Fish l–3 years old made up 64% of the biomass, whereas fish of harvestable size (≥4 years old) made up only 31% of the biomass. Year-class strength was variable among years, but a Ricker recruitment function described the relation between year-class strength and parental stock size, Age-specific mortality increased substantially as fish became sexually mature at age 4, perhaps as a result of energy depletion associated with high reproductive and maintenance costs in a suboptimal thermal environment. Yield-per-recruit analysis indicated that most of the age-specific annual mortality was due to natural causes. Natural mortality, rather than limited recruitment or fishing mortality, was the major factor controlling harvestable stock size, Regardless of the size of a year-class produced, natural mortality greatly reduced its abundance prior to maturity and recruitment to the fishable stock. This high mortality, combined with very slow growth, limits the biomass potential of the harvestable stock, and sustainable yields from this population are therefore low.

  15. Olfactory recovery of wild yellow perch from metal contaminated lakes.

    PubMed

    Azizishirazi, Ali; Dew, William A; Forsyth, Heidi L; Pyle, Greg G

    2013-02-01

    Fish depend on their sense of smell for a wide range of vital life processes including finding food, avoiding predators and reproduction. Various contaminants, including metals, can disrupt recognition of chemical information in fish at very low concentrations. Numerous studies have investigated metal effects on fish olfaction under controlled laboratory conditions. However, few have measured olfactory acuity using wild fish in source water. In this study, we used electro-olfactography (EOG) to measure the olfactory acuity of wild yellow perch (Perca flavescens) from a clean lake (Geneva Lake) and two metal contaminated lakes (Ramsey and Hannah lakes) from Sudbury, ON, in their own lake water or in water from the other lakes. The results showed that fish from the clean lake had a greater olfactory acuity than those from metal contaminated lakes when fish were tested in their own lake water. However, when fish from the clean lake were held for 24h in water from each of the two contaminated lakes their olfactory acuity was diminished. On the other hand, fish from the contaminated lakes held for 24h in clean lake water showed a significant olfactory recovery relative to that measured in their native lake water. These results show that although fish from a clean lake demonstrated impaired olfaction after only 24h in metal-contaminated water, fish from metal contaminated lakes showed a rapid olfactory recovery when exposed to clean water for only hours. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Assessing controls on perched saturated zones beneath the Idaho Nuclear Technology and Engineering Center, Idaho

    USGS Publications Warehouse

    Mirus, Benjamin B.; Perkins, Kim S.; Nimmo, John R.

    2011-01-01

    Waste byproducts associated with operations at the Idaho Nuclear Technology and Engineering Center (INTEC) have the potential to contaminate the eastern Snake River Plain (ESRP) aquifer. Recharge to the ESRP aquifer is controlled largely by the alternating stratigraphy of fractured volcanic rocks and sedimentary interbeds within the overlying vadose zone and by the availability of water at the surface. Beneath the INTEC facilities, localized zones of saturation perched on the sedimentary interbeds are of particular concern because they may facilitate accelerated transport of contaminants. The sources and timing of natural and anthropogenic recharge to the perched zones are poorly understood. Simple approaches for quantitative characterization of this complex, variably saturated flow system are needed to assess potential scenarios for contaminant transport under alternative remediation strategies. During 2009-2011, the U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Energy, employed data analysis and numerical simulations with a recently developed model of preferential flow to evaluate the sources and quantity of recharge to the perched zones. Piezometer, tensiometer, temperature, precipitation, and stream-discharge data were analyzed, with particular focus on the possibility of contributions to the perched zones from snowmelt and flow in the neighboring Big Lost River (BLR). Analysis of the timing and magnitude of subsurface dynamics indicate that streamflow provides local recharge to the shallow, intermediate, and deep perched saturated zones within 150 m of the BLR; at greater distances from the BLR the influence of streamflow on recharge is unclear. Perched water-level dynamics in most wells analyzed are consistent with findings from previous geochemical analyses, which suggest that a combination of annual snowmelt and anthropogenic sources (for example, leaky pipes and drainage ditches) contribute to recharge of shallow and

  17. The immune responses and expression of metallothionein (MT) gene and heat shock protein 70 (HSP 70) in juvenile rockfish, Sebastes schlegelii, exposed to waterborne arsenic (As(3+)).

    PubMed

    Kim, Jun-Hwan; Kang, Ju-Chan

    2016-10-01

    Juvenile rockfish, Sebastes schlegelii (mean length 16.4±1.9cm, and mean weight 71.6±6.4g) were exposed for 20days with the different levels of waterborne arsenic concentration (0, 50, 100, 200 and 400μg/L). The plasma cortisol of S. schlegelii was significantly increased by the waterborne arsenit exposure. In the immune responses, the immunoglobulin M (Ig M) and lysozyme activity of S. schlegelii were significantly increased by the waterborne arsenic exposure. The acetylcholinesterase (AChE) activity of S. schlegelii was inhibited by the waterborne arsenic exposure. The substantial increases in the gene expression such as metallothionein (MT) and heat shock protein 70 (HSP 70) were observed by the waterborne arsenic exposure. The results demonstrated that waterborne arsenic exposure can induce the significant alterations in the immune responses and specific gene expression of S. schlegelii.

  18. Evidence of hypoxic foraging forays by yellow perch (Perca flavescens) and potential consequences for prey consumption

    USGS Publications Warehouse

    Roberts, James J.; Grecay, Paul A.; Ludsin, Stuart A.; Pothoven, Steve A.; Vanderploeg, Henry A.; Höök, Tomas O.

    2012-01-01

    Previous studies in a variety of ecosystems have shown that ecologically and economically important benthic and bentho-pelagic fishes avoid hypoxic (−1) habitats by moving vertically or horizontally to more oxygenated areas. While avoidance of hypoxic conditions generally leads to a complete shift away from preferred benthic prey, some individual fish continue to consume benthic prey items in spite of bottom hypoxia, suggesting complex habitat utilisation and foraging patterns. For example, Lake Erie yellow perch (Perca flavescens) continue to consume benthic prey, despite being displaced vertically and horizontally by hypolimnetic hypoxia. We hypothesised that hypolimnetic hypoxia can negatively affect yellow perch by altering their distribution and inducing energetically expensive foraging behaviour. To test this hypothesis, we used drifting hydroacoustics and trawl sampling to quantify water column distribution, sub-daily vertical movement and foraging behaviour of yellow perch within hypoxic and normoxic habitats of Lake Erie’s central basin during August-September 2007. We also investigated the effects of rapid changes in ambient oxygen conditions on yellow perch consumption potential by exposing yellow perch to various static and fluctuating oxygen conditions in a controlled laboratory experiment. Our results indicate that, while yellow perch in general avoid hypoxic conditions, some individuals undertake foraging forays into hypoxic habitats where they experience greater fluctuations in abiotic conditions (pressure, temperature and oxygen concentration) than at normoxic sites. However, laboratory results suggest short-term exposure to low oxygen conditions did not negatively impact consumption potential of yellow perch. Detailed understanding of sub-daily individual behaviours may be crucial for determining interactive individual- and ecosystem-level effects of stressors such as hypoxia.

  19. Cool perches improve the growth performance and welfare status of broiler chickens reared at different stocking densities and high temperatures.

    PubMed

    Zhao, J P; Jiao, H C; Jiang, Y B; Song, Z G; Wang, X J; Lin, H

    2013-08-01

    The present study investigated the interaction of stocking density and cool perch availability on broiler chickens raised at high ambient temperature (>30.8°C). Behavior, live performance, and the incidence of footpad and hock burns and abdominal plumage damage were investigated over a 4-wk experimental period. A total of 1,152 one-day-old Arbor Acres chicks were subjected to a 2 (cool perches) × 3 (stocking densities) factorial arrangement of treatments. From 1 d of age, birds were provided with or without cool perches at each of 3 stocking densities (12, 16, or 20 birds/m(2); low, medium, or high stocking density, respectively) and corresponded to 48, 64, and 80 birds per pen. The perch design provided 380 cm of linear perching space in each treatment pen. The results showed that high stocking density decreased the growth (P < 0.05) and welfare (P < 0.01) of broilers. Cool perch availability increased BW gain and feed conversion efficiency of broilers (P < 0.05) regardless of stocking density. The birds' use of cool perches increased with age (P < 0.01) and decreased with higher stocking density (P < 0.05). The accessibility of cool perches changed birds' behavior patterns (P < 0.01) and reduced footpad or hock burns and damage to abdominal plumage (P < 0.05). These results suggest that cool perches have a favorable effect on the performance and welfare of broilers.

  20. Increasing Mercury in Yellow Perch at a Hotspot in Atlantic Canada, Kejimkujik National Park

    PubMed Central

    2010-01-01

    In the mid-1990s, yellow perch (Perca flavescens) and common loons (Gavia immer) from Kejimkujik National Park and National Historic Site (KNPNHS), Nova Scotia, Canada, had among the highest mercury (Hg) concentrations across North America. In 2006 and 2007, we re-examined 16 lakes to determine whether there have been changes in Hg in the loon’s preferred prey, yellow perch. Total Hg concentrations were measured in up to nine perch in each of three size classes (5−10 cm, 10−15 cm, and 15−20 cm) consumed by loons. Between 1996/97 and 2006/07, polynomial regressions indicated that Hg in yellow perch increased an average of 29% in ten lakes, decreased an average of 21% in three, and were unchanged in the remaining three lakes. In 2006/07, perch in 75% of the study lakes had Hg concentrations (standardized to 12-cm fish length) equal to or above the concentration (0.21 μg·g−1 ww) associated with a 50% reduction in maximum productivity of loons, compared with only 56% of these lakes in 1996/97. Mercury contamination currently poses a greater threat to loon health than a decade ago, and further reductions in anthropogenic emissions should be considered to reduce its impacts on ecosystem health. PMID:21062071

  1. Who Is Who: An Anomalous Predator-Prey Role Exchange between Cyprinids and Perch

    PubMed Central

    Blabolil, Petr; Jůza, Tomáš; Vašek, Mojmír; Ricard, Daniel; Matěna, Josef; Frouzová, Jaroslava; Kubečka, Jan; Říha, Milan

    2016-01-01

    Piscivory in cyprinids (Cyprinidae) is extremely rare. Specifically, common bream (Abramis brama) and common carp (Cyprinus carpio) are zooplanktivorous fish in deep lentic waters. Nevertheless, we observed predation by these two cyprinids under natural conditions in the Vír Reservoir, Czech Republic. We conducted diet analysis for cyprinids caught by trawling and gillnets and the large amount of young-of-the-year (YOY) perch (Perca fluviatilis), with sizes of 37–52 mm standard length, were found in their digestive tracts. In 2010, a large amount of YOY perch caused a significant decrease in Daphnia spp. size and abundance in the reservoir. Hence, a food deficit was induced for the cyprinids, apparent also from the poor nutritional condition of common bream which was much worse than the condition of those in similar reservoirs. Common carp and common bream shifted to forced piscivory, and they utilized the YOY perch as an alternative food source. In contrast, smaller species, such as roach (Rutilus rutilus) and bleak (Alburnus alburnus), widely utilized planktonic cyanobacteria. In the following year, YOY perch occurred in significantly lower numbers and conversely, Daphnia spp. size and abundance were significantly higher. The forced piscivory was not observed. Our results indicate a switch to forced piscivory by cyprinids, which was caused by a shortage of their natural food source. Moreover, this phenomenon presents an effective mechanism for reduction in the numbers of YOY perch, ensuring the stability of the ecosystem. PMID:27276078

  2. Who Is Who: An Anomalous Predator-Prey Role Exchange between Cyprinids and Perch.

    PubMed

    Vejřík, Lukáš; Matějíčková, Ivana; Seďa, Jaromír; Blabolil, Petr; Jůza, Tomáš; Vašek, Mojmír; Ricard, Daniel; Matěna, Josef; Frouzová, Jaroslava; Kubečka, Jan; Říha, Milan; Čech, Martin

    2016-01-01

    Piscivory in cyprinids (Cyprinidae) is extremely rare. Specifically, common bream (Abramis brama) and common carp (Cyprinus carpio) are zooplanktivorous fish in deep lentic waters. Nevertheless, we observed predation by these two cyprinids under natural conditions in the Vír Reservoir, Czech Republic. We conducted diet analysis for cyprinids caught by trawling and gillnets and the large amount of young-of-the-year (YOY) perch (Perca fluviatilis), with sizes of 37-52 mm standard length, were found in their digestive tracts. In 2010, a large amount of YOY perch caused a significant decrease in Daphnia spp. size and abundance in the reservoir. Hence, a food deficit was induced for the cyprinids, apparent also from the poor nutritional condition of common bream which was much worse than the condition of those in similar reservoirs. Common carp and common bream shifted to forced piscivory, and they utilized the YOY perch as an alternative food source. In contrast, smaller species, such as roach (Rutilus rutilus) and bleak (Alburnus alburnus), widely utilized planktonic cyanobacteria. In the following year, YOY perch occurred in significantly lower numbers and conversely, Daphnia spp. size and abundance were significantly higher. The forced piscivory was not observed. Our results indicate a switch to forced piscivory by cyprinids, which was caused by a shortage of their natural food source. Moreover, this phenomenon presents an effective mechanism for reduction in the numbers of YOY perch, ensuring the stability of the ecosystem.

  3. The impacts of ontogenetic dietary shifts in yellow perch (Perca flavescens) on Zn and Hg accumulation.

    PubMed

    Kraemer, Lisa D; Evans, Douglas; Dillon, Peter J

    2012-04-01

    Yellow perch (Perca flavescens) undergo several ontogenetic dietary shifts, and consequently these fish feed at different trophic levels and rely on different carbon sources over their lifetime. Stable isotope ratios of nitrogen (δ(15)N) and carbon (δ(13)C) are powerful ecological tools that are used to provide a temporally integrated description of the feeding ecology of aquatic animals such as fish. The main objective of this study was to use stable isotopes of nitrogen and carbon to determine if dietary changes affected mercury (Hg) and zinc (Zn) accumulation in yellow perch ranging in size from approximately 5 cm to 27 cm. Results showed that Hg bioaccumulation generally increased with increasing trophic level in fish feeding at higher trophic levels, however, the relationship between Hg levels and δ(15)N was non-linear showing no relationship in small fish (less than 15 cm). In contrast, there was a negative, linear relationship between δ(15)N and Zn, suggesting that as perch fed at progressively higher trophic levels, less of Zn bioaccumulated. No relationship was observed between δ(13)C and metal levels in perch. Collectively, these results demonstrate a contrast in the behavior of Zn and Hg bioaccumulation in yellow perch as a function of trophic status. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Water Transparency Drives Intra-Population Divergence in Eurasian Perch (Perca fluviatilis)

    PubMed Central

    Bartels, Pia; Hirsch, Philipp E.; Svanbäck, Richard; Eklöv, Peter

    2012-01-01

    Trait combinations that lead to a higher efficiency in resource utilization are important drivers of divergent natural selection and adaptive radiation. However, variation in environmental features might constrain foraging in complex ways and therefore impede the exploitation of critical resources. We tested the effect of water transparency on intra-population divergence in morphology of Eurasian perch (Perca fluviatilis) across seven lakes in central Sweden. Morphological divergence between near-shore littoral and open-water pelagic perch substantially increased with increasing water transparency. Reliance on littoral resources increased strongly with increasing water transparency in littoral populations, whereas littoral reliance was not affected by water transparency in pelagic populations. Despite the similar reliance on pelagic resources in pelagic populations along the water transparency gradient, the utilization of particular pelagic prey items differed with variation in water transparency in pelagic populations. Pelagic perch utilized cladocerans in lakes with high water transparency and copepods in lakes with low water transparency. We suggest that under impaired visual conditions low utilization of littoral resources by littoral perch and utilization of evasive copepods by pelagic perch may lead to changes in morphology. Our findings indicate that visual conditions can affect population divergence in predator populations through their effects on resource utilization. PMID:22912895

  5. Perched groundwater at the northwestern coast of Egypt: a case study of the Fuka Basin

    NASA Astrophysics Data System (ADS)

    Yousif, Mohamed; Bubenzer, Olaf

    2012-03-01

    Perched groundwater resources on the northwestern coast of Egypt have thus far been little studied. However, if replenished by rainwater, they can provide a considerable amount of renewable water, i.e., for sustainable irrigation. These resources are limited, show different salinity contents and are endangered by overuse, pollution and by the sea level rising in the context of global warming. This paper presents new climatic data, geomorphologic, geologic, geochemical and hydrological researches in combination with remote sensing and GIS applications from Fuka Basin. Fuka constitutes a special synclinal basin where the interbedded limestone and clays have been folded into gentle synclinal structures. Fractured Middle Miocene limestone represents the bearing formation for the perched groundwater. According to the hydrogeochemical analysis and the PHREEQC model, the aquifer is recharged during the winter season by rainwater from the surrounding tableland and the chemical evolution of the perched water is attributed to water-rock interaction and mixing of fresh water with sea water. The salinity of the perched water ranges from 2,126 to 2,644 mg/L whereas for the deep groundwater it reaches 9,800 mg/L. The study explores origin and potential of the perched groundwater of Fuka Basin and gives recommendations for a future sustainable use and further investigations.

  6. Evaluating the low back biomechanics of three different office workstations: Seated, standing, and perching.

    PubMed

    Le, Peter; Marras, William S

    2016-09-01

    The objective of this study was to evaluate how different workstations may influence physical behavior in office work through motion and how that may affect spinal loads and discomfort. Twenty subjects performed a typing task in three different workstations (seated, standing, and perching) for one hour each. Measures of postural transitions, spinal loads, discomfort, and task performance were assessed in order to understand the effects of workstation interaction over time. Results indicated that standing had the most amount of motion (6-8 shifts/min), followed by perching (3-7 shifts/min), and then seating (<1 shift/min). Standing had the highest reports of discomfort and seating the least. However, spinal loads were highest in A/P shear during standing (190N posterior shear, 407N anterior shear) compared to perching (65N posterior shear, 288N anterior shear) and seating (106N posterior shear, 287 anterior shear). These loads are below the risk threshold for shear, but may still elicit a cumulative response. Perching may induce motion through supported mobility in the perching stool, whereas standing motion may be due to postural discomfort. Office workstation designs incorporating supported movement may represent a reasonable trade-off in the costs-benefits between seating and standing.

  7. Night sampling improves indices used for management of yellow perch in Lake Erie

    USGS Publications Warehouse

    Kocovsky, P.M.; Stapanian, M.A.; Knight, C.T.

    2010-01-01

    Catch rate (catch per hour) was examined for age-0 and age-1 yellow perch, Perca flavescens (Mitchill), captured in bottom trawls from 1991 to 2005 in western Lake Erie: (1) to examine variation of catch rate among years, seasons, diel periods and their interactions; and (2) to determine whether sampling during particular diel periods improved the management value of CPH data used in models to project abundance of age-2 yellow perch. Catch rate varied with year, season and the diel period during which sampling was conducted as well as by the interaction between year and season. Indices of abundance of age-0 and age-1 yellow perch estimated from night samples typically produced better fitting models and lower estimates of age-2 abundance than those using morning or afternoon samples, whereas indices using afternoon samples typically produced less precise and higher estimates of abundance. The diel period during which sampling is conducted will not affect observed population trends but may affect estimates of abundance of age-0 and age-1 yellow perch, which in turn affect recommended allowable harvest. A field experiment throughout western Lake Erie is recommended to examine potential benefits of night sampling to management of yellow perch. Published 2010. The article is a US Government work and is in the public domain in the USA.

  8. Water transparency drives intra-population divergence in Eurasian Perch (Perca fluviatilis).

    PubMed

    Bartels, Pia; Hirsch, Philipp E; Svanbäck, Richard; Eklöv, Peter

    2012-01-01

    Trait combinations that lead to a higher efficiency in resource utilization are important drivers of divergent natural selection and adaptive radiation. However, variation in environmental features might constrain foraging in complex ways and therefore impede the exploitation of critical resources. We tested the effect of water transparency on intra-population divergence in morphology of Eurasian perch (Perca fluviatilis) across seven lakes in central Sweden. Morphological divergence between near-shore littoral and open-water pelagic perch substantially increased with increasing water transparency. Reliance on littoral resources increased strongly with increasing water transparency in littoral populations, whereas littoral reliance was not affected by water transparency in pelagic populations. Despite the similar reliance on pelagic resources in pelagic populations along the water transparency gradient, the utilization of particular pelagic prey items differed with variation in water transparency in pelagic populations. Pelagic perch utilized cladocerans in lakes with high water transparency and copepods in lakes with low water transparency. We suggest that under impaired visual conditions low utilization of littoral resources by littoral perch and utilization of evasive copepods by pelagic perch may lead to changes in morphology. Our findings indicate that visual conditions can affect population divergence in predator populations through their effects on resource utilization.

  9. Enzymatic correlates of energy status in wild yellow perch inhabiting clean and contaminated environments.

    PubMed

    Gauthier, Charles; Campbell, Peter G C; Couture, Patrice

    2011-09-01

    Enzymes representing a variety of metabolic pathways were examined in yellow perch (Perca flavescens) collected from a metal-contaminated region (Rouyn-Noranda, Québec, Canada) to determine which were most closely related to fish condition factor, pyloric caeca weight, and visceral lipid accumulation, as well to seek a better understanding of the influence of metal contamination on the physiology and biometrics of perch. Compared to laboratory fish, wild perch were under important energy restrictions. The condition factor of wild fish was correlated with indicators of aerobic metabolism (citrate synthase, cytochrome C oxidase), protein anabolism (nucleoside diphosphokinase), and indicators of lipid accumulation (glucose-6-phosphate dehydrogenase, visceral lipid index). Pyloric caeca weights were well correlated with indicators of protein anabolism, but only when both seasons were examined together, possibly indicating a lag in the response of enzymes to changes in diet. The addition of contaminant stress to existing energy restrictions led to changes in the relationships between enzymes and biometrics, reducing the predictive power of the models for perch in contaminated lakes. The present study broadens our knowledge of the impact of metal contamination on energy accumulation and tissue metabolic capacities in wild perch.

  10. Influence of Smallmouth Bass predation on recruitment of age-0 Yellow Perch in South Dakota glacial lakes

    USGS Publications Warehouse

    Dembkowski, Daniel J.; Willis, D.W.; Blackwell, B. G.; Chipps, Steven R.; Bacula, T. D.; Wuellner, M.R.

    2015-01-01

    We estimated the influence of predation by Smallmouth Bass Micropterus dolomieu on recruitment of age-0 Yellow Perch Perca flavescens in two northeastern South Dakota glacial lakes. We estimated a likely range in consumption of age-0 Yellow Perch using Smallmouth Bass diet information from two time periods when age-0 Yellow Perch constituted high (2008) and low (2012 and 2013) proportions of Smallmouth Bass diets, and bass population size estimates as inputs in a bioenergetics model. The proportion of age-0 Yellow Perch consumed by the Smallmouth Bass populations was determined by comparing estimates of consumption with estimates of age-0 perch production. During 2008, age-0 Yellow Perch constituted between 0% and 42% of Smallmouth Bass diets by weight, whereas during 2012 and 2013, age-0 perch constituted between 0% and 20% of bass diets by weight. Across both lakes and time periods, production of age-0 Yellow Perch ranged from 0.32 to 1.78 kg·ha−1·week−1. Estimates of Smallmouth Bass consumption measured during the same intervals ranged from 0.06 to 0.33 kg·ha−1·week−1, equating to consumption of between 1% and 34% of the available Yellow Perch biomass. Given current conditions relative to Smallmouth Bass abundance and consumption dynamics and production of age-0 Yellow Perch, it does not appear that Smallmouth Bass predation acts as a singular factor limiting recruitment of age-0 Yellow Perch in our study lakes. However, future research and management initiatives should recognize that the long-term impact of Smallmouth Bass predation is not static and will likely fluctuate depending on environmental (e.g., temperature) and biotic (e.g., trends in macrophyte abundance, predator and prey population structure and abundance, and predatory fish assemblage dynamics) characteristics.

  11. Evaluation of metal content in perch of the Ob River basin

    NASA Astrophysics Data System (ADS)

    Osipova, N. A.; Stepanova, K. D.; Matveenko, I. A.

    2015-11-01

    The geochemical features of river perch in the River Ob basin have been studied (the upper and middle reaches of the Ob River and the lower reach of the Tom River). The contents of Ag, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sn, W, Zn, Hg in perch's soft tissue are defined by the methods of ICP AES and stripping voltammetry, that of mercury in bones - by the atomic absorption method using mercury analyzer PA-915+. The distribution series of metal absolute concentrations in perch's soft tissue from the Ob River basin are plotted: Fe > Zn > Cu > Mn, typical for uncontaminated or slightly metal contaminated water bodies. In soft tissue of the studied samples the metal content does not exceed the permissible values. The mercury content in bones of studied samples is in the range 0,036-0,556 mg/kg. The mercury concentration is higher in bones in comparison with soft tissue in all samples.

  12. Cormorant predation and the population dynamics of walleye and yellow perch in Oneida Lake

    USGS Publications Warehouse

    Rudstam, L. G.; VanDeValk, A.J.; Adams, C.M.; Coleman, J.T.H.; Forney, J.L.; Richmond, M.E.

    2004-01-01

    Double-crested Cormorants (Phalacrocorax auritus) increased dramatically in North America during the 1990s, providing the opportunity to study the effects of an increase of a top predator on an existing predator-prey system. In Oneida Lake, New York, USA, Double-crested Cormorants were first observed nesting in 1984 and had increased to over 360 nesting pairs by 2000. Concomitant with this increase in piscivorous birds was a decrease in the adult walleye (Stizostedion vitreum) and yellow perch (Perca flavescens) populations. Analysis of a 40-yr data series shows higher mortality of subadults (age 1-2 yr perch and age 1-3 yr walleye) for both species in the 1990s compared to the previous three decades. Cormorant diet was investigated from 1995 to 2000 using a combination of cast pellets, regurgitants, and stomach analysis. Walleye and yellow perch were a major portion of the cormorant diet during these years (40-82% by number). The number of subadult walleye and yellow perch consumed by cormorants suggests that the increase in subadult mortality can be explained by predation from cormorants. Mean mortality rates of adult percids attributed to cormorant predation were 1.1% per year for walleye and 7.7% per year for yellow perch. Our analysis suggests that predation by cormorants on subadult percids is a major factor contributing to the decline in both the walleye and the yellow perch populations in Oneida Lake. Other ecosystem changes (zebra mussels, lower nutrient loading, decrease in alternate prey) are not likely explanations because the potential mechanisms involved are not consistent with auxiliary data from the lake and would not affect subadult mortality. The likely impact of bird predation on percid populations in Oneida Lake occurs because cormorants feed on larger fish that are beyond the size range where compensatory mechanisms are important.

  13. First isolation of a rhabdovirus from perch Perca fluviatilis in Switzerland.

    PubMed

    Wahli, Thomas; Bellec, Laure; von Siebenthal, Beat; Cabon, Joëlle; Schmidt-Posthaus, Heike; Morin, Thierry

    2015-10-16

    Perca fluviatilis is a fish species of increasing interest to the Swiss fish farming industry. In recent years, recirculation systems have been specifically set up to increase production. In one of these farms, abnormal spiral swimming associated with elevated mortalities occurred in repeated batches of imported perch shortly after stocking on several occasions. No bacterial or parasitic etiology was detected, but a virus grown in bluegill fry (BF-2) cells was identified as perch rhabdovirus. Subsequent investigations of other samples suggested a viral tropism for the central nervous system (CNS). Phylogenetic analysis of the partial N and entire G gene sequences positioned this isolate in genogroup C of the species Perch rhabdovirus, with high nucleotide and amino acid (aa) sequence identities with the DK5533 strain isolated in Denmark in 1989. Comparative studies using other closely related isolates allowed the distinction of 2 serological patterns among perch rhabdoviruses and the identification of a proline substitution by a serine in position 147 of the glycoprotein potentially involved in antigenic differentiation. Even if perch imported onto the farm tested negative by virus isolation prior to transport, they may have been the origin of this outbreak since CNS tissue was not included in the samples that were analyzed. Another possibility might be a sub-clinical infection with a viral load in resident fish too low to be detected. This study reports the first isolation of a perch rhabdovirus in Switzerland, and emphasizes the necessity of optimizing diagnostic tools that facilitate better control of the risks associated with fish translocation.

  14. Population biology of yellow perch in southern Lake Michigan, 1971-79

    USGS Publications Warehouse

    Wells, LaRue; Jorgenson, Sherrell C.

    1983-01-01

    This study was based mainly on gill-net collections of yellow perch (Perca flavescens) made during July and August 1971-79, in southern Lake Michigan at Grand Haven, Saugatuck, South Haven, Benton Harbor, and New Buffalo, Michigan; Michigan City and Gary, Indiana; Waukegan, Illinois; and Milwaukee, Wisconsin. Abundance of yellow perch was above the 1971-79 average in 1971 and 1972, below average in 1979, and about average or in doubt in the other years. Abundance during 1976-79 was greatest at Saugatuck and decreased more or less progressively from Saugatuck southward and around the southern end of the lake. The geographical differences in abundance were attributable partly to differences in fishing mortality. Average lengths of fish caught were greatest at Saugatuck, and generally greater in Michigan waters than in other areas; they were greater for females than for males. Fish sampled ranged in age from I to IX, but 88% of the males and 81% of the females were of ages II-V. Older perch were generally more common in State of Michigan waters, particularly at Saugatuck, than elsewhere. Females grew faster than males after the second year of life. Average lengths of males and females at the end of 3 years were 197 and 214 mm, respectively, in Michigan waters and 186 and 195 mm in Indiana-Illinois (few perch were caught in Wisconsin). The relation of weight (W) to length (L) for combined sexes was W = 2.6761(10-6) x L3.2644. Perch in southeastern Lake Michigan spawned mainly from late May to mid June. Virtually all males were mature in their second year, but some females not until their fourth year. Perch 174 to 355 mm long contained 9, 300 to 136, 000 eggs. Approximate mortalities of males and females in Michigan waters were 52% and 48%, respectively; rates were higher in Indiana-Illinois.

  15. Interactions among zebra mussel shells, invertebrate prey, and Eurasian ruffe or yellow perch

    USGS Publications Warehouse

    Kolar, C.S.; Fullerton, A.H.; Martin, K.M.; Lamberti, G.A.

    2002-01-01

    The exotic zebra mussel, Dreissena polymorpha, is established in all of the Laurentian Great Lakes and may affect benthivorous fishes by increasing the complexity of benthic substrates and changing energy flow patterns within the food web. Native yellow perch, Perca flavescens, and the nonindigenous Eurasian ruffe, Gymnocephalus cernuus, are benthivores that may compete for limited food resources. As ruffe spread to areas with more dense zebra mussel populations, the zone of interaction among zebra mussels, yellow perch, and ruffe will increase and intensify. In the laboratory, the effect of zebra mussel shells on the ability of these fishes to forage on amphipods (Gammarus pseudolimnaeus) and chironomids (Chironomus plumosus) was examined in light and darkness. In 12 h, ruffe consumed more amphipods than did similar-sized yellow perch, particularly in darkness on bare cobble, and in light within zebra mussels. Amphipods decreased activity more in the presence of ruffe than yellow perch. More amphipods were found in zebra mussel shells than in bare cobble, whether or not fish were present. In darkness, when ruffe consumed more amphipods on bare cobble, amphipods became more associated with zebra mussel shells. Although ruffe consumed more amphipods than yellow perch, perch consumed more chironomids than ruffe on bare cobble. The presence of zebra mussel shells altered the relative consumption of invertebrates in some substrate-light combinations. Experiments such as these help to improve understanding of the direct and indirect effects of predation between and among native and nonindigenous species that may exert structuring forces on the nearshore communities of the Great Lakes currently or in the future.

  16. Age, growth, and production of the yellow perch, Perca flavescens (Mitchill), of Saginaw Bay

    USGS Publications Warehouse

    Hile, Ralph; Jobes, Frank W.

    1941-01-01

    Ages were determined and individual growth histories computed from the examination and measurement of scales from 820 yellow perch collected in 1929 and 1930. Calculated lengths greater than 101 millimeters were computed on the assumption (supported by empirical data) that the ratio of body length to scale length is constant. Lengths below 101 millimeters were determined with the aid of an empirical curve of the body-scale relationship of small fish. Yellow perch of age-groups III and IV (in the fourth and fifth years of life) made up the bulk of the collection (78 per cent). Females grew slightly more rapidly than males, but members of both sexes attained the legal length of 8 1/2 inches during the fourth year of life, just as they were entering on the period of most rapid growth in weight. The greatest growth in weight of both sexes occurred in the sixth year of life. In the combined samples of the two years the females exceeded the males in abundance in the ratio, 296:100. The weight of the Saginaw Bay yellow perch was found to increase as the 3.117 power of the length. The relative length of the tail decreased with increase in the length of the fish. The Saginaw Bay yellow perch is now far less abundant than it was in the early years of the fishery. The average annual production of 548,000 pounds over the period, 1917-1938, was only 28 per cent of the earlier (1891-1916) "normal" annual production of 1,961,000 pounds. A detailed analysis of statistical data available for more recent years made possible a description of annual fluctuations in the abundance and production of yellow perch and in the intensity of the yellow perch fishery in Saginaw Bay over the period, 1929-1938.

  17. Analysis of Expressed Sequence Tags from the Liver and Brain of Estrogen Treated Yellow Perch (Perca flavescens)

    USDA-ARS?s Scientific Manuscript database

    Over the last decade, there has been strong interest in the aquaculture of yellow perch (Perca flavescens) in North America. We have been developing genetically defined yellow perch broodstocks for aquaculture using genetic analyses and selection methods. However, aside from microsatellites, there...

  18. The effect of perches in cages during pullet rearing and egg laying on hen performance, foot health, and plumage

    USDA-ARS?s Scientific Manuscript database

    Our objective was to determine if perch availability during all or part of the life cycle of caged Hy-Line W-36 chickens affected egg traits, foot health, and feather condition. Using a 2 x 2 factorial arrangement, treatment 1 represented control chickens which never had access to perches during the...

  19. Early evolution of avian flight and perching: new evidence from the lower cretaceous of china.

    PubMed

    Sereno, P C; Chenggang, R

    1992-02-14

    Fossil bird skeletons discovered in Lower Cretaceous lake deposits in China shed new light on the early evolution of avian flight and perching. The 135 million-year-old sparrow-sized skeletons represent a new avian, Sinornis santensis, n. gen. n. sp., that preserves striking primitive features such as a flexible manus with unguals, a footed pubis, and stomach ribs (gastralia). In contrast to Archaeoperyx, however, Sinornis exhibits advanced features such as a broad sternum, wing-folding mechanism, pygostyle, and large fully reversed hallux. Modern avian flight function and perching capability, therefore, must have evolved in small-bodied birds in inland habitats not long after Archaeopteryx.

  20. Molecular characterization of neuropeptide Y gene in Chinese perch, an acanthomorph fish.

    PubMed

    Liang, Xu-Fang; Li, Guang-Zhao; Yao, Wei; Cheong, Lai-Wan; Liao, Wan-Qin

    2007-09-01

    The full-length neuropeptide Y (NPY) cDNA of Chinese perch Siniperca chuatsi was 704 bp in length, and contained a 300 bp open reading frame encoding a prepro-NPY with 99 amino acids. The predicted prepro-NPY peptide contained a putative signal peptide of 28 amino acids and a mature NPY of 36 amino acids, followed by the proteolytic processing site Gly-Lys-Arg and 35 amino acids that comprise the C-terminal peptide of NPY. Amino acid alignment and phylogenetic analysis indicate that the predicted Chinese perch prepro-NPY (composed of 99 amino acids) had high identities to the prepro-NPY of acanthomorph fishes (93-95%), whereas it had much lower identities to the prepro-NPY (composed of 96 or 97 amino acids) of cyprinid fishes (59-60%) or mammals (57-63%). Chinese perch NPY gene consists of four exons and three introns. The ratio of intron 2 to intron 3 was over 14 in Chinese perch NPY gene, whereas this ratio was below 4 in zebrafish and mammalian NPY gene. The total size of the Chinese perch NPY gene was 2223 bp, which was only about 28% of the size of NPY gene in higher vertebrate. Analysis of a 1622 bp promoter region of Chinese perch NPY gene, revealed a typical TATA box, a GC box and an untypical CAAT box, located at 84 bp, 101 bp and 303 bp upstream of the start codon respectively. Three STAT binding site-like elements (TCCAGTA) which were necessary for the leptin-induced transcriptional control of rat NPY gene were identified. In consistence to the effect of cortisol on fish brain NPY mRNA expression, four glucocorticoid-responsive elements were detected. Besides the highest expression in brain, substantial level of Chinese perch NPY mRNA expression was detected in the spleen and liver, and trace level of NPY mRNA expression was also detected in the adipose tissue, intestine and muscle. These results indicated that Chinese perch NPY might be involved in the food intake control by leptin and cortisol system, and diversification of NPY signaling should exist

  1. Development of perching behavior in 3 strains of pullets reared in furnished cages.

    PubMed

    Habinski, A M; Caston, L J; Casey-Trott, T M; Hunniford, M E; Widowski, T M

    2017-03-01

    Furnished rearing cages are becoming more widely available to replace conventional systems for pullets. To date, there is little information on how pullets develop perching behavior in furnished cages or how this varies among strains. The objective of this study was to evaluate the use of perches and a platform in a commercial furnished rearing "Combi-Cage" system by 3 pure-bred heritage strains of pullets (Rhode Island Red, Columbian Rock, and White Leghorn). Each cage had 4 elevated locations: one platform and 3 perches of differing heights and positions in the cage. The length of each cage was visually divided into 4 sections for observation. The number of birds using each section in each location was counted by one observer d per wk at 1200 h (d) from one to 14 wk of age and at 1600 h (night) right after lights were turned off from 4 to 14 wk of age. Mixed model repeated analyses were used to test effects of strain, age, and their interaction on the use of the platform, the 3 perches, and all 4 locations combined (vertical space use) at both time periods. GLM were used to compare overall use of the sections and locations. On average, pullets used vertical space more during the d than at night. There were also effects of age (P < 0.05) and strain (P < 0.05) on the use of the 4 locations in the cage at both time periods. Generally, the Columbian Rocks used the perches and platform the most, and Rhode Island Reds the least. The highest perch in the cage was rarely used and birds showed a preference for perching in sections that were closest to cage walls (P < 0.05). Differences across strains and low use of some perch locations indicate that the design of furnished rearing cages may still require improvements in order to ensure the furnishings are used by pullets as intended. © 2016 Poultry Science Association Inc.

  2. The Effects of Zebra Mussels (Dreissena polymorpha) on the Foraging Success of Eurasian Perch (Perca fluviatilis) and Ruffe (Gymnocephalus cernuus)

    NASA Astrophysics Data System (ADS)

    Dieterich, Axel; Mörtl, Martin; Eckmann, Reiner

    2004-07-01

    Complex habitat structures can influence the foraging success of fish. Competition for food between fish species can therefore depend on the competitors' abilities to cope with structural complexity. In laboratory experiments, we comparatively assessed effects of zebra mussels (Dreissena polymorpha Pall.) on the foraging success of Eurasian perch (Perca fluviatilis L.) and ruffe (Gymnocephalus cernuus (L.)). In single-species and mixed-species experiments, the fish were fed caddisfly larvae (Tinodes waeneri (L.)) over complex (mussel-covered stones) and less-complex (bare stones) substrates. With intraspecific competition, food consumption by perch and ruffe decreased significantly when the complex substrate was used. With interspecific competition, food consumption by perch and ruffe did not change with substrate complexity, but perch clearly out-competed ruffe on both substrates. Zebra mussel beds provide a refuge for macrozoobenthos against predation by ruffe and probably also by perch. (

  3. Effects of long-term changes in the benthic community on yellow perch in Saginaw Bay, Lake Huron

    USGS Publications Warehouse

    Schaeffer, Jeffrey S.; Diana, James S.; Haas, Robert C.

    2000-01-01

    Abundance, mortality, age and growth, food habits, and energetics of a yellow perch Perca flavescens population were investigated in eutrophic Saginaw Bay, Lake Huron during May to October, 1986 to 1988, and compared population characteristics with historical data from times when eutrophic conditions were less severe. During 1986 to 1988, yellow perch were abundant, but grew slowly and experienced high natural mortality. A size threshold was present at 150 to 180 mm beyond which few individuals survived, and sex ratios became biased toward males. An energetic model suggested that yellow perch were food limited; as they increased in size they spent a greater proportion of the growing season near maintenance ration. Low feeding rates were a consequence of subsistence on small chironomid larvae. Piscivory provided little energetic relief. Historical data suggested that availability of large benthic prey such as nymphs of the burrowing mayfly Hexagenia was important to yellow perch. Yellow perch formerly consumed Hexagenia, but mayflies were extirpated from Saginaw Bay during 1953 to 1965, and never recovered. When Hexagenia was present, yellow perch growth was moderate to fast depending on population size, size thresholds were not present, and yellow perch reached large size and older age despite moderate to high fishing mortality. Decreases in yellow perch growth rates during 1952 to 1955 coincided with extirpation of Hexagenia. Fast growth of yellow perch did occur after Hexagenia became extirpated, but only when fishing mortality was high, population size was small, and some large benthic invertebrates remained. Eutrophication of Saginaw Bay appeared to affect yellow perch by changing species composition and reducing size structure of the benthic community.

  4. The role of perched aquifers in hydrological connectivity and biogeochemical processes in vernal pool landscapes, Central Valley, California

    NASA Astrophysics Data System (ADS)

    Cable Rains, Mark; Fogg, Graham E.; Harter, Thomas; Dahlgren, Randy A.; Williamson, Robert J.

    2006-03-01

    Relatively little is known about the role of perched aquifers in hydrological, biogeochemical, and biological processes of vernal pool landscapes. The objectives of this study are to introduce a perched aquifer concept for vernal pool formation and maintenance and to examine the resulting hydrological and biogeochemical phenomena in a representative catchment with three vernal pools connected to one another and to a seasonal stream by swales. A combined hydrometric and geochemical approach was used. Annual rainfall infiltrated but perched on a claypan/duripan, and this perched groundwater flowed downgradient toward the seasonal stream. The upper layer of soil above the claypan/duripan is 0.6 m in thickness in the uplands and 0.1 m in thickness in the vernal pools. Some groundwater flowed through the vernal pools when heads in the perched aquifer exceeded 0.1 m above the claypan/duripan. Perched groundwater discharge accounted for 30-60% of the inflow to the vernal pools during and immediately following storm events. However, most perched groundwater flowed under or around the vernal pools or was recharged by annual rainfall downgradient of the vernal pools. Most of the perched groundwater was discharged to the outlet swale immediately upgradient of the seasonal stream, and most water discharging from the outlet swale to the seasonal stream was perched groundwater that had not flowed through the vernal pools. Therefore, nitrate-nitrogen concentrations were lower (e.g. 0.17 to 0.39 mg l-1) and dissolved organic carbon concentrations were higher (e.g. 5.97 to 3.24 mg l-1) in vernal pool water than in outlet swale water discharging to the seasonal stream. Though the uplands, vernal pools, and seasonal stream are part of a single surface-water and perched groundwater system, the vernal pools apparently play a limited role in controlling landscape-scale water quality.

  5. Short-Term Fidelity, Habitat Use and Vertical Movement Behavior of the Black Rockfish Sebastes schlegelii as Determined by Acoustic Telemetry

    PubMed Central

    Zhang, Yingqiu; Xu, Qiang; Alós, Josep; Liu, Hui; Xu, Qinzeng; Yang, Hongsheng

    2015-01-01

    The recent miniaturization of acoustic tracking devices has allowed fishery managers and scientists to collect spatial and temporal data for sustainable fishery management. The spatial and temporal dimensions of fish behavior (movement and/or vertical migrations) are particularly relevant for rockfishes (Sebastes spp.) because most rockfish species are long-lived and have high site fidelity, increasing their vulnerability to overexploitation. In this study, we describe the short-term (with a tracking period of up to 46 d) spatial behavior, as determined by acoustic tracking, of the black rockfish Sebastes schlegelii, a species subject to overexploitation in the Yellow Sea of China. The average residence index (the ratio of detected days to the total period from release to the last detection) in the study area was 0.92 ± 0.13, and most of the tagged fish were detected by only one region of the acoustic receiver array, suggesting relatively high site fidelity to the study area. Acoustic tracking also suggested that this species is more frequently detected during the day than at night in our study area. However, the diel detection periodicity (24 h) was only evident for certain periods of the tracking time, as revealed by a continuous wavelet transform. The habitat selection index of tagged S. schlegelii suggested that S. schlegelii preferred natural reefs, mixed sand/artificial reef bottoms and mixed bottoms of boulder, cobble, gravel and artificial reefs. The preference of this species for the artificial reefs that were recently deployed in the study area suggests that artificial seascapes may be effective management tools to attract individuals. The vertical movement of tagged S. schlegelii was mostly characterized by bottom dwelling behavior, and there was high individual variability in the vertical migration pattern. Our results have important implications for S. schlegelii catchability, the implementation of marine protected areas, and the identification of key

  6. Developmental expression and estrogen responses of endocrine genes in juvenile yellow perch (Perca flavescens)

    USDA-ARS?s Scientific Manuscript database

    The present study examines the expression of growth-regulating genes (gh, prl, smtl and igf1b), the estrogen receptors (esr1 and esr2a) and aromatase (cyp19a1a) in developing yellow perch. To gain an initial understanding into the endocrine control of growth preceding and involved with sexual size d...

  7. Morphological evidence for discrete stocks of yellow perch in Lake Erie

    USGS Publications Warehouse

    Kocovsky, Patrick M.; Knight, Carey T.

    2012-01-01

    Identification and management of unique stocks of exploited fish species are high-priority management goals in the Laurentian Great Lakes. We analyzed whole-body morphometrics of 1430 yellow perch Perca flavescens captured during 2007–2009 from seven known spawning areas in Lake Erie to determine if morphometrics vary among sites and management units to assist in identification of spawning stocks of this heavily exploited species. Truss-based morphometrics (n = 21 measurements) were analyzed using principal component analysis followed by ANOVA of the first three principal components to determine whether yellow perch from the several sampling sites varied morphometrically. Duncan's multiple range test was used to determine which sites differed from one another to test whether morphometrics varied at scales finer than management unit. Morphometrics varied significantly among sites and annually, but differences among sites were much greater. Sites within the same management unit typically differed significantly from one another, indicating morphometric variation at a scale finer than management unit. These results are largely congruent with recently-published studies on genetic variation of yellow perch from many of the same sampling sites. Thus, our results provide additional evidence that there are discrete stocks of yellow perch in Lake Erie and that management units likely comprise multiple stocks.

  8. Recruitment synchrony of yellow perch (Perca flavescens, Percidae) in the Great Lakes region, 1966–2008

    USGS Publications Warehouse

    Honsey, Andrew E.; Bunnell, David; Troy, Cary D.; Fielder, David G.; Thomas, Michael V.; Knight, Carey T.; Chong, Stephen; Hook, Tomas O.

    2016-01-01

    Population-level reproductive success (recruitment) of many fish populations is characterized by high inter-annual variation and related to annual variation in key environmental factors (e.g., climate). When such environmental factors are annually correlated across broad spatial scales, spatially separated populations may display recruitment synchrony (i.e., the Moran effect). We investigated inter-annual (1966–2008) variation in yellow perch (Perca flavescens, Percidae) recruitment using 16 datasets describing populations located in four of the five Laurentian Great Lakes (Erie, Huron, Michigan, and Ontario) and Lake St. Clair. We indexed relative year class strength using catch-curve residuals for each year-class across 2–4 years and compared relative year-class strength among sampling locations. Results indicate that perch recruitment is positively synchronized across the region. In addition, the spatial scale of this synchrony appears to be broader than previous estimates for both yellow perch and freshwater fish in general. To investigate potential factors influencing relative year-class strength, we related year-class strength to regional indices of annual climatic conditions (spring-summer air temperature, winter air temperature, and spring precipitation) using data from 14 weather stations across the Great Lakes region. We found that mean spring-summer temperature is significantly positively related to recruitment success among Great Lakes yellow perch populations.

  9. Production of genetically defined perch broodstocks and their selection for fast growth

    USDA-ARS?s Scientific Manuscript database

    The restrictions and closures of commercial freshwater fisheries in North America, coupled with continued high consumer demand, have fueled interest in yellow perch aquaculture. However, the general slow growth of this species and the lack of commercially available genetically improved broodstocks h...

  10. A note on the effects of perches and litter substrate on leg weakness in broiler chickens.

    PubMed

    Su, G; Sørensen, P; Kestin, S C

    2000-09-01

    Two trials were conducted to investigate the effect of availability of perches on indices of leg weakness in broiler chickens. A third trial investigated the effect of litter substrate on similar indices of leg weakness in broiler chickens. Leg weakness traits examined were walking ability and tibial dyschondroplasia, tibial curvature, foot burn, and hock burn. Body weight was also measured in all trials. The presence of perches in the rearing pens had no effect on any of the indices of leg weakness examined in either trial. There were no consistent effects of perches on BW. Litter substrate significantly affected some indices of leg weakness; birds reared on wheat straw had poorer walking ability and more foot burn than birds reared on wood shavings, and birds reared on hemp waste were intermediate between them. There was no effect of litter substrate on tibial dyschondroplasia or tibial curvature. Turning the straw litter regularly and adding fresh supplies when necessary did not significantly improve indices of leg weakness. It was concluded that wood shavings provide a better litter substrate than straw, but that perches have no beneficial effect on reducing leg weakness in broilers.

  11. Effect of Feeding-Fasting Cycles on Oxygen Consumption and Bioenergetics of Yellow Perch

    USGS Publications Warehouse

    Chipps, Steven R.; Travis W. Schaeffer,; Daniel E. Spengler,; Casey W. Schoenebeck,; Michael L. Brown,

    2012-01-01

    We measured growth and oxygen consumption of age-1 yellow perch Perca flavescenssubjected to ad libitum (control) or variable feeding cycles of 2 (i.e., 2 d of feed, 2 d of deprivation), 6, or 12 d for a 72-d period. Individual, female yellow perch (initial weight = 51.9 ± 0.9 g [mean ± SE]) were stocked in 110-L aquaria to provide six replicates per treatment and fed measured rations of live fathead minnow Pimephales promelas. Consumption, absolute growth rate, growth efficiency, and oxygen consumption were similar among feeding regimens. However, growth trajectories for fish on the 2-d cycle were significantly lower than other feed–fast cycles. Hyperphagia occurred in all treatments. Bioenergetics model simulations indicated that consumption was significantly underestimated (t = 5.4, df = 4, P = 0.006), while growth was overestimated (t = −5.5, df = 4, P = 0.005) for fish on the 12-d cycle. However, model errors detected between observed and predicted values were low, ranging from −10.1% to +7.8%. We found that juvenile yellow perch exhibited compensatory growth (CG), but none of the feed–fast treatments resulted in growth overcompensation. Likewise, we found no evidence that respiration rates varied with CG, implying that yellow perch bioenergetics models could be used to predict the effects of feeding history and CG response on food consumption and fish growth.

  12. Yellow perch nutrient utilization and performance fed grower diet formulations with fermented soybean concentrate

    USDA-ARS?s Scientific Manuscript database

    Feeds formulated with fermented soybean concentrate (FSBC) were processed using a pilot-scale Wenger twin screw extruder, using a 1.9 cm diameter circular die, and then fed to juvenile yellow perch (Perca flavescens) (~26g) as a protein replacer for fish meal protein. Four fish-meal replacement lev...

  13. Status and prospects for the yellow perch genetic improvement program in Milwaukee, Wisconsin

    USDA-ARS?s Scientific Manuscript database

    In 2004, a broodstock improvement program was initiated with the aim of developing defined geographic strains of yellow perch that have been selected for improved growth. Following a survey of 19 populations ranging from the Mid-West to the Eastern coast of the United States, and subsequent efforts ...

  14. CHARACTERIZATION OF GENES INVOLVED WITH GROWTH AND IMMUNITY IN THE YELLOW PERCH (PERCA FLAVESCENS)

    USDA-ARS?s Scientific Manuscript database

    In most vertebrates, growth hormone (GH) stimulates growth, metabolism and immunity. In yellow perch, GH does not appear to stimulate growth which suggests a condition of GH insensitivity. Furthermore, females grow faster and larger than males and estrogen preferentially stimulates this growth. T...

  15. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (North Atlantic). WHITE PERCH,

    DTIC Science & Technology

    1983-10-01

    salin- (Scott and Crossman 1973). White perch ities up to 30 ppt. Salinity affects do not depend on vegetation, rocks, the water balance of deposited eggs...Aphredoderidae through Rachy - Bigelow, H.B., and W.C. Schroeder. centridae. U.S. Fish and Wildlife 1953. Fishes of the Gulf of Service, Biological Services Maine

  16. Myxobolus neurophilus: a common myxosporidian parasite infecting yellow perch Perca flavacens (Mitchell) in Saskatchewan, Canada

    USDA-ARS?s Scientific Manuscript database

    The goal of this study was to identify a myxosporidian parasite infecting the central nervous system of yellow perch Perca flavacens (Mitchell) observed while investigating a fish kill in Saskatchewan, Canada. Fish were collected from seven different lakes, from 2 distinct watersheds. Sixty-four p...

  17. Cooled perch effects on performance and well-being traits in caged White Leghorn hens

    USDA-ARS?s Scientific Manuscript database

    We assessed the effects of chilled water cooling perches on hen performance, feather condition, foot health, and physiological and behavioral parameters during the 2013 summer with a 4-h acute heating episode. White Leghorn pullets at 16 wk of age were randomly assigned to 18 cages arranged into 3 b...

  18. Perched-Water Evaluation for the Deep Vadose Zone Beneath the B, BX, and BY Tank Farms Area of the Hanford Site

    SciTech Connect

    Truex, Michael J.; Oostrom, Martinus; Carroll, KC; Chronister, Glen B.

    2013-06-28

    Perched-water conditions have been observed in the vadose zone above a fine-grained zone that is located a few meters above the water table within the B, BX, and BY Tank Farms area. The perched water contains elevated concentrations of uranium and technetium-99. This perched-water zone is important to consider in evaluating the future flux of contaminated water into the groundwater. The study described in this report was conducted to examine the perched-water conditions and quantitatively evaluate 1) factors that control perching behavior, 2) contaminant flux toward groundwater, and 3) associated groundwater impact.

  19. Metals in Nile perch (Lates niloticus) and suspended particulate matter from Lake Victoria, Tanzania.

    PubMed

    Machiwa, John F

    2005-01-01

    A study was conducted to assess the levels of pollutant metals in suspended particulate matter and Nile perch from Lake Victoria. The metals in particulate matter were determined to ascertain their concentrations at the base of the food chain. Nile perch samples were collected in September 2003 from five major fish processing factories at the shores of Lake Victoria in Mwanza and Musoma. The concentrations of total Hg, Pb, Cd, and Cu were generally low in particulate matter and in most locations were close to or below their limits of detection. The concentrations of Zn were high in suspended particulate matter, the highest being 219.4 +/- 153.0 microg L(-1) found in particulate matter from Nungwe Bay in the southern part of Lake Victoria. Nile perch generally contained low levels of heavy metals; the range for Pb was <0.01-0.08 microg g(-1) ww, Cd was <0.001-0.04 microg g(-1) ww, Cu was 0.01-0.97 microg g(-1) ww, and Zn was <0.01-18.94 microg g(-1) ww. The concentration of total mercury ranged between 31.0 and 684.2 ng g(-1) ww; generally, it was below the Food and Agriculture Organization of the United Nations/World Health Organization (1000 ng total Hg g(-1) ww for piscivorous fish species) maximum allowable level. Indeed, all Nile perch samples that weighed less than 10 kg had less than 200 ng total Hg g(-1) ww and therefore are safe for regular consumption by at-risk groups such as children and pregnant women. Levels of mercury and other heavy metals in Nile perch at present is, therefore, not a severe environmental issue; however, urgent regulatory measures should be taken to minimize metal input into the lake to maintain the current levels in the fish.

  20. Lake Erie Yellow perch age estimation based on three structures: Precision, processing times, and management implications

    USGS Publications Warehouse

    Vandergoot, C.S.; Bur, M.T.; Powell, K.A.

    2008-01-01

    Yellow perch Perca flavescens support economically important recreational and commercial fisheries in Lake Erie and are intensively managed. Age estimation represents an integral component in the management of Lake Erie yellow perch stocks, as age-structured population models are used to set safe harvest levels on an annual basis. We compared the precision associated with yellow perch (N = 251) age estimates from scales, sagittal otoliths, and anal spine sections and evaluated the time required to process and estimate age from each structure. Three readers of varying experience estimated ages. The precision (mean coefficient of variation) of estimates among readers was 1% for sagittal otoliths, 5-6% for anal spines, and 11-13% for scales. Agreement rates among readers were 94-95% for otoliths, 71-76% for anal spines, and 45-50% for scales. Systematic age estimation differences were evident among scale and anal spine readers; less-experienced readers tended to underestimate ages of yellow perch older than age 4 relative to estimates made by an experienced reader. Mean scale age tended to underestimate ages of age-6 and older fish relative to otolith ages estimated by an experienced reader. Total annual mortality estimates based on scale ages were 20% higher than those based on otolith ages; mortality estimates based on anal spine ages were 4% higher than those based on otolith ages. Otoliths required more removal and preparation time than scales and anal spines, but age estimation time was substantially lower for otoliths than for the other two structures. We suggest the use of otoliths or anal spines for age estimation in yellow perch (regardless of length) from Lake Erie and other systems where precise age estimates are necessary, because age estimation errors resulting from the use of scales could generate incorrect management decisions. ?? Copyright by the American Fisheries Society 2008.

  1. Robust post-stall perching with a simple fixed-wing glider using LQR-Trees.

    PubMed

    Moore, Joseph; Cory, Rick; Tedrake, Russ

    2014-06-01

    Birds routinely execute post-stall maneuvers with a speed and precision far beyond the capabilities of our best aircraft control systems. One remarkable example is a bird exploiting post-stall pressure drag in order to rapidly decelerate to land on a perch. Stall is typically associated with a loss of control authority, and it is tempting to attribute this agility of birds to the intricate morphology of the wings and tail, to their precision sensing apparatus, or their ability to perform thrust vectoring. Here we ask whether an extremely simple fixed-wing glider (no propeller) with only a single actuator in the tail is capable of landing precisely on a perch from a large range of initial conditions. To answer this question, we focus on the design of the flight control system; building upon previous work which used linear feedback control design based on quadratic regulators (LQR), we develop nonlinear feedback control based on nonlinear model-predictive control and 'LQR-Trees'. Through simulation using a flat-plate model of the glider, we find that both nonlinear methods are capable of achieving an accurate bird-like perching maneuver from a large range of initial conditions; the 'LQR-Trees' algorithm is particularly useful due to its low computational burden at runtime and its inherent performance guarantees. With this in mind, we then implement the 'LQR-Trees' algorithm on real hardware and demonstrate a 95 percent perching success rate over 147 flights for a wide range of initial speeds. These results suggest that, at least in the absence of significant disturbances like wind gusts, complex wing morphology and sensing are not strictly required to achieve accurate and robust perching even in the post-stall flow regime.

  2. Comparison of bone volume and strength as measures of skeletal integrity in caged laying hens with access to perches.

    PubMed

    Hughes, B O; Wilson, S; Appleby, M C; Smith, S F

    1993-03-01

    Fractures in spent laying hens are now recognised as a major welfare problem; the objective of this work was to determine whether provision of perches for caged layers would increase bone strength, bone volume or both. Sixteen ISA Brown hens were housed from 18 to 72 weeks old in cages with perches and 16 in similar cages without perches. At the end of lay the birds' tibiotarsi were examined for strength by a three-point loading test and their tarsometatarsi for bone volume by histomorphometry. There was no significant effect of perches on tibiotarsal breaking strength. Hens from both groups showed evidence of osteoporosis, but it was more severe in the birds from conventional cages: tarsometatarsal trabecular bone volume was greater in the hens which had access to perches. A positive correlation was found between trabecular bone volume and the degree of day-time perch usage by individual hens. Provision of perches can have a slight but significant beneficial effect, at least for the leg bones, in increasing the bone volume of caged laying hens.

  3. Season-related changes in circulating androgen, brain aromatase, and perch-calling in male ring doves.

    PubMed

    Fusani, Leonida; Van't Hof, Thomas; Hutchison, John B

    2003-02-01

    The perch-call of ring doves (Streptopelia risoria) is related to territorial defence and mate attraction. Perch-calls are sexually dimorphic and individually different in structure. The expression of perch-call is androgen-dependent and is controlled by the action of testosterone on the preoptic-hypothalamic areas. However, it is not known whether the acoustic features of the call vary with the reproductive condition. We studied plasma androgen levels, brain steroid metabolism, and perch-calling of male ring doves kept in winter-like (low temperature, short days) or spring-like (mild temperature, long day) conditions. Circulating levels of androgen were higher in males kept on spring-like condition. Spring males spent more time in perch-calling than winter males. However, a detailed analysis of the call structure revealed no difference for any time or frequency parameter between groups. This work shows that in ring doves season-dependent variations in the circulating levels of androgen are correlated with differences in the amount of time males spend in perch-calling. In addition, the study suggests that in adult males the acoustic structure of the perch-calls is not influenced by season-related changes in androgen levels.

  4. Fyke-net and gill-net size selectivities for yellow perch in Green Bay, Lake Michigan

    USGS Publications Warehouse

    Kraft, J.A.; Johnson, B.L.

    1992-01-01

    We estimated a fyke-net selectivity function for yellow perch Perca flavescens in Green Bay, Lake Michigan, by comparing length-frequency distributions of yellow perch captured in fyke nets with different mesh sizes in 1986. Using a length--girth relationship for Green Bay yellow perch, we expressed selectivity as the ratio of girth (G) to effective mesh perimeter (P), which was 5a??7% less than nominal mesh perimeter. Then, fitting an existing gill-net selectivity function to the Green Bay yellow perch fishery, we found fyke-net and gill-net selectivities were similar, with similar G /P ratios, but fyke nets had smaller effective mesh perimeters and thus were more efficient at capturing smaller yellow perch for any given mesh size, The derived fyke-net selectivity function can be used to determine mesh sizes that minimize the sublegal catch of yellow perch in this fishery and could be applied to entrapment gear in other yellow perch fisheries, given data on the lengtha??girth relationships and effective mesh perimeters.

  5. Stimulative effect of skipjack tuna soluble extract on pepsin-like protease in the stomach of rockfish (Sebastes schlegelii) using an in vitro perfusion method.

    PubMed

    Kihara, Minoru; Igarashi, Makoto; Suzuki, Tomohiro; Itou, Fumiaki; Kozeni, Satoshi; Toyomane, Mihoko; Nakano, Junko; Yamai, Ikumi

    2011-04-01

    The effect of intra-gastric infusion of skipjack tuna (Katsuwonus pelamis) muscle soluble extract and of carnosine, anserine and histidine, on pepsin-like protease activity was studied in the isolated, externally batch-cultured stomach of the rockfish (Sebastes schlegelii). Stomach was isolated from the fish, then intragastrically infused with the above solutions or with a balanced saline solution (control solution) as the stimulant at 0.1 mL/min for 6h. Intra-gastric efflux was collected for measurement of pepsin-like protease activity. Skipjack tuna soluble extract, but not carnosine, anserine or histidine alone caused significant enhancement of pepsin-like protease activity during the infusion. Pepsin-like protease activity from skipjack tuna soluble extract responded immediately after infusion and was kept for 150 min after infusion. Stomach motility at the end of infusion was also observed. These results suggest that isolated stomach can receive mucosal side stimulants in vitro. It is likely that some effective components for stomach digestion in fish exist in skipjack tuna soluble extract. Copyright © 2010 Elsevier Inc. All rights reserved.

  6. Prevalence and spatial distribution of intraerythrocytic parasite(s) in Puget Sound rockfish (Sebastes emphaeus) from the San Juan Archipelago, Washington (USA)

    USGS Publications Warehouse

    Van Der Straaten, N.; Jacobson, A.; Halos, D.; Hershberger, P.; Kocan, A.A.; Kocan, R.

    2005-01-01

    Two morphologically distinct forms of an intraerythrocytic parasite(s) were detected by microscopic observation of Giemsa-stained blood films in 45.7% of 119 rockfish (Sebastes emphaeus) from the San Juan Archipelago (Washington State, U.S.A.). Infection prevalence for both forms was 53% in males, 44% in females, and 33% in fish of undetermined gender. A binucleate "ring-stage" was present at all 4 geographic sites, with a mean prevalence of 45.7%, while mean prevalence of a larger gamont-like form from the same sites was 5.1%. The relationship of the 2 forms to each other could not be determined. Neither schizogony nor binary fission was evident in any of the infected erythrocytes and the parasites contained no obvious pigment. The possibility of the 2 morphologic forms being 2 distinct species is supported by the observation that no difference in parasitemia was seen in the binucleate form among sites (1.6-1.9%), while parasitemia of the gamont-like form varied significantly among sites, ranging from a high of 4% to a low of 0.1%. Taxonomic status of either form could not be determined at this time based on limited existing morphologic data. ?? American Society of Parasitologists 2005.

  7. Evaluation of rockfish conservation area networks in the United States and Canada relative to the dispersal distance for black rockfish (Sebastes melanops)

    PubMed Central

    Lotterhos, Katie E; Dick, Stefan J; Haggarty, Dana R

    2014-01-01

    Marine reserves networks are implemented as a way to mitigate the impact of fishing on marine ecosystems. Theory suggests that a reserve network will function synergistically when connected by dispersal, but the scale of dispersal is often unknown. On the Pacific coast of the United States and Canada, both countries have recently implemented a number of rockfish conservation areas (RCAs) to protect exploited rockfish species, but no study has evaluated the connectivity within networks in each country or between the two countries. We used isolation-by-distance theory to estimate the scale of dispersal from microsatellite data in the black rockfish, Sebastes melanops, and compared this estimate with the distance between RCAs that would protect this species. Within each country, we found that the distance between RCAs was generally within the confidence intervals of mean dispersal per generation. The distance between these two RCA networks, however, was greater than the average dispersal per generation. The data were also consistent with a genetic break between southern Oregon and central Oregon. We discuss whether additional nearshore RCAs in southern Oregon and Washington would help promote connectivity between RCA's for shallow-water rockfishes. PMID:24567745

  8. The application of stereo-video technology for the assessment on population change of black rockfish Sebastes schlegeli in a vessel reef area in Haizhou Bay, China

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Xu, Qiang; Xu, Qinzeng; Zhang, Yingqiu; Yang, Hongsheng

    2015-01-01

    The assessment of population structure and abundance of fish assemblages associated with artificial reefs (ARs) is an important aspect of AR management. In the present study, we used a Dive-Operated Stereo Video (stereo-DOV) technique to assess the population structure and abundance of Sebastes schlegeli associated with two metallic, and three wooden, vessel reefs in Haizhou Bay during 2012 and 2013. The study used video systems to obtain length measurements and estimates of abundance. The size composition of S. schlegeli differed among reefs and individuals around vessel reefs were all adults, with total lengths (TL) of >20 cm. Juvenile fish were encountered by divers in a rocky area near the island away from the vessel reefs. The largest individual S. schlegeli (with the highest TL) among five reefs were found around a metallic vessel reef in both 2012 and 2013. TL of S. s chlegeli from all reefs increased by an average of 3.2 cm ( P<0.05) from 2012 to 2013, with an estimated mean weight increase of 250.4 g ( P<0.05). The video survey also indicated a decrease in the biomass of schools near two metallic vessels between the years. Stereo-video technology was found to be suitable for rockfish surveys around the reefs.

  9. Parasites as Biological Tags for Stock Discrimination of Beaked Redfish (Sebastes mentella): Parasite Infra-Communities vs. Limited Resolution of Cytochrome Markers

    PubMed Central

    Klapper, Regina; Kochmann, Judith; O’Hara, Robert B.; Karl, Horst; Kuhn, Thomas

    2016-01-01

    The use of parasites as biological tags for discrimination of fish stocks has become a commonly used approach in fisheries management. Metazoan parasite community analysis and anisakid nematode population genetics based on a mitochondrial cytochrome marker were applied in order to assess the usefulness of the two parasitological methods for stock discrimination of beaked redfish Sebastes mentella of three fishing grounds in the North East Atlantic. Multivariate, model-based approaches demonstrated that the metazoan parasite fauna of beaked redfish from East Greenland differed from Tampen, northern North Sea, and Bear Island, Barents Sea. A joint model (latent variable model) was used to estimate the effects of covariates on parasite species and identified four parasite species as main source of differences among fishing grounds; namely Chondracanthus nodosus, Anisakis simplex s.s., Hysterothylacium aduncum, and Bothriocephalus scorpii. Due to its high abundance and differences between fishing grounds, Anisakis simplex s.s. was considered as a major biological tag for host stock differentiation. Whilst the sole examination of Anisakis simplex s.s. on a population genetic level is only of limited use, anisakid nematodes (in particular, A. simplex s.s.) can serve as biological tags on a parasite community level. This study confirmed the use of multivariate analyses as a tool to evaluate parasite infra-communities and to identify parasite species that might serve as biological tags. The present study suggests that S. mentella in the northern North Sea and Barents Sea is not sub-structured. PMID:27104735

  10. Parasites as Biological Tags for Stock Discrimination of Beaked Redfish (Sebastes mentella): Parasite Infra-Communities vs. Limited Resolution of Cytochrome Markers.

    PubMed

    Klapper, Regina; Kochmann, Judith; O'Hara, Robert B; Karl, Horst; Kuhn, Thomas

    2016-01-01

    The use of parasites as biological tags for discrimination of fish stocks has become a commonly used approach in fisheries management. Metazoan parasite community analysis and anisakid nematode population genetics based on a mitochondrial cytochrome marker were applied in order to assess the usefulness of the two parasitological methods for stock discrimination of beaked redfish Sebastes mentella of three fishing grounds in the North East Atlantic. Multivariate, model-based approaches demonstrated that the metazoan parasite fauna of beaked redfish from East Greenland differed from Tampen, northern North Sea, and Bear Island, Barents Sea. A joint model (latent variable model) was used to estimate the effects of covariates on parasite species and identified four parasite species as main source of differences among fishing grounds; namely Chondracanthus nodosus, Anisakis simplex s.s., Hysterothylacium aduncum, and Bothriocephalus scorpii. Due to its high abundance and differences between fishing grounds, Anisakis simplex s.s. was considered as a major biological tag for host stock differentiation. Whilst the sole examination of Anisakis simplex s.s. on a population genetic level is only of limited use, anisakid nematodes (in particular, A. simplex s.s.) can serve as biological tags on a parasite community level. This study confirmed the use of multivariate analyses as a tool to evaluate parasite infra-communities and to identify parasite species that might serve as biological tags. The present study suggests that S. mentella in the northern North Sea and Barents Sea is not sub-structured.

  11. Evaluation of rockfish conservation area networks in the United States and Canada relative to the dispersal distance for black rockfish (Sebastes melanops).

    PubMed

    Lotterhos, Katie E; Dick, Stefan J; Haggarty, Dana R

    2014-02-01

    Marine reserves networks are implemented as a way to mitigate the impact of fishing on marine ecosystems. Theory suggests that a reserve network will function synergistically when connected by dispersal, but the scale of dispersal is often unknown. On the Pacific coast of the United States and Canada, both countries have recently implemented a number of rockfish conservation areas (RCAs) to protect exploited rockfish species, but no study has evaluated the connectivity within networks in each country or between the two countries. We used isolation-by-distance theory to estimate the scale of dispersal from microsatellite data in the black rockfish, Sebastes melanops, and compared this estimate with the distance between RCAs that would protect this species. Within each country, we found that the distance between RCAs was generally within the confidence intervals of mean dispersal per generation. The distance between these two RCA networks, however, was greater than the average dispersal per generation. The data were also consistent with a genetic break between southern Oregon and central Oregon. We discuss whether additional nearshore RCAs in southern Oregon and Washington would help promote connectivity between RCA's for shallow-water rockfishes.

  12. Molecular cloning and expression analysis of estrogen receptor betas (ERβ1 and ERβ2) during gonad development in the Korean rockfish, Sebastes schlegeli.

    PubMed

    Mu, W J; Wen, H S; Shi, D; Yang, Y P

    2013-07-01

    Estrogen receptors (ER) play a crucial role in mediation of estrogen activities. Here we report the isolation and expression analysis of ERβ1 and ERβ2 from ovary Korean rockfish (Sebastes schlegeli). were isolated using reverse transcription-polymerase chain reaction (PCR) and rapid amplification of cDNA ends procedures. The cDNA of this study, ERβ1 (588 amino acids) and ERβ2 (659 amino acids) were identified using reverse-transcriptase PCR (RT-PCR) and rapid amplification of cDNA ends procedures. Structural analysis showed both ERβs contain six typical nuclear receptor-characteristic domains. Phylogenetic analysis indicated that Korean rockfish ERβs were highly conserved among teleost. RT-PCR confirmed that the ERβs were widely distributed in both gonads and extra gonadal tissues. Further, we analyzed the expression patterns of male and female S. schlegeli during the reproductive cycle using quantitative real-time PCR (qRT-PCR). The results showed that the highest expression levels were observed in testis at immature sperm stage for both of KrERβ1 and KrERβ2. For female, the expressions of KrERβ1 and KrERβ2 were significantly higher in the ovary at the early-oocyte stage. Cloning these two ERβ subtypes in the Korean rockfish, together with the information on expression levels in adult fish has given us the foundation to investigate their possible role in brain-pituitary-gonad neuroendocrine axis in future studies.

  13. The role of melano-macrophage aggregates in the storage of mercury and other metals: an example from yelloweye rockfish (Sebastes ruberrimus).

    PubMed

    Barst, Benjamin D; Bridges, Kristin; Korbas, Malgorzata; Roberts, Aaron P; Van Kirk, Kray; McNeel, Kevin; Drevnick, Paul E

    2015-08-01

    Melano-macrophage aggregates, collections of specialized cells of the innate immune system of fish, are considered a general biomarker for contaminant toxicity. To elucidate further the relationship between macrophage aggregates and metals exposure, yelloweye rockfish (Sebastes ruberrimus), a long-lived species, were sampled from the east and west coasts of Prince of Wales Island, Alaska. Metals concentrations in livers (inorganic Hg, methyl mercury, Se, Ni, Cd, Cu, Zn) and spleens (inorganic Hg and methyl mercury) were determined, as well as their correlations with melano-macrophage aggregate area. Sections of liver tissue were analyzed by laser ablation-inductively coupled plasma-mass spectrometry to determine how metals were spatially distributed between hepatocytes and macrophage aggregates. The concentration of inorganic Hg in whole tissue was the best predictor of macrophage area in yelloweye livers and spleens. Macrophage aggregates had higher relative concentrations than most metals compared with the surrounding hepatocytes. However, not all metals were accumulated to the same degree, as evidenced by differences in the ratios of metals in macrophages compared with hepatocytes. Laser ablation data were corroborated with the results of X-ray synchrotron fluorescence imaging of a yelloweye liver section. Hepatic macrophage aggregates in yelloweye rockfish may play an important role in the detoxification and storage of Hg and other metals.

  14. Remedies for a high incidence of broken eggs in furnished cages: effectiveness of increasing nest attractiveness and lowering perch height.

    PubMed

    Tuyttens, F A M; Struelens, E; Ampe, B

    2013-01-01

    Two remedial treatments to reduce the high incidence of broken eggs in the furnished cages of our experimental layer farm were investigated: lining the nest floor with artificial turf (to increase nest acceptance) and lowering perch height (to reduce the chance of egg breakage of outside-nest eggs). A 2 × 2 factorial design was used with low (7 cm) or high (24 cm) perches, and with nest floors lined with artificial turf or plastic mesh. Eight cages, each housing 8 hens initially (aged 40 to 56 wk), were used per treatment. Egg location and percentage of broken eggs were recorded. Hen position (cage floor, nest, or perch) was recorded by direct scan-sampling observations. In addition, 8 cages (4 high + 4 low) each containing 8 hens (aged 54 to 56 wk) were videorecorded to determine perch use and behavior during the light period. Data were mainly analyzed using logistic regression and mixed models with cage as the experimental unit. Nest floor material did not influence the percentage of eggs broken or laid outside the nest. The proportion of outside-nest eggs (2.6 vs. 10.6%, P = 0.004), and consequently also of total eggs (2 vs. 4.6%, P = 0.016) broken, was lower for low than high cages. Perch use increased during the observation period, more so for the high cages during the light period and the low cages during the dark period. Perch bout duration (P < 0.001), the likelihood of ending a perching bout voluntarily (P = 0.013), and time spent sitting during perching (P = 0.007) were lower in low vs. high cages. In this study, replacing plastic mesh nest floor lining with artificial turf was not an effective remedy for the already-high rate of broken eggs, but the prevalence of broken outside-nest eggs was lower in cages with low versus high perches. However, perching behavior during the light period was more disturbed in cages with low perches.

  15. Endocrine disruption and altered gonadal development in white perch (Morone americana) from the lower Great Lakes region.

    PubMed Central

    Kavanagh, Richard J; Balch, Gordon C; Kiparissis, Yiannis; Niimi, Arthur J; Sherry, Jim; Tinson, Cheryl; Metcalfe, Chris D

    2004-01-01

    High prevalences of gonadal intersex have been observed in wild fish populations in areas affected by domestic and industrial effluents. For this study, fish were collected in 1998 from the Cootes Paradise region of Hamilton Harbour in western Lake Ontario, Canada, to determine whether gonadal abnormalities, including intersex, were present in young of the year (YOY) fish. No gonadal abnormalities were observed in goldfish (Carassius auratus), common carp (Cyprinus carpio), gizzard shad (Dorosoma cepedianum), brown bullhead (Ictalurus ameiurus), pumpkinseed (Lepomis gibbosus), and bluegill (Lepomis macrochirus). However, intersex gonads were observed in 8 of 16 male white perch (Morone americana) examined in this survey. Subsequently, in 1999 and 2000 white perch estimated to be YOY to approximately 2 years of age were collected from Cootes Paradise and from two other sites in the lower Great Lakes region. Gonadal intersex was observed in male white perch collected from the Bay of Quinte (22-44%) and Lake St. Clair (45%), although the prevalence and the extent of the intersex condition were lower relative to the 83% prevalence in white perch collected in Cootes Paradise. Intersex was not observed in hatchery-reared white perch or in white perch collected from an uncontaminated reference site (i.e., Deal Lake) in the United States. An analysis of plasma collected in the spring of 2002 from male adult white perch in Cootes Paradise revealed high concentrations of vitellogenin, ranging from 49 to 1,711 microg/mL. These observations indicate that male white perch are exposed to estrogenic endocrine-disrupting substances that may be responsible for the induction of gonadal intersex. PMID:15175179

  16. Of Paleo-Genes and Perch: What if an “Alien” Is Actually a Native?

    PubMed Central

    Stager, J. Curt; Sporn, Lee Ann; Johnson, Melanie; Regalado, Sean

    2015-01-01

    Documenting whether a biotic taxon is native or alien to an ecosystem has theoretical value for ecological and evolutionary studies, and has practical value because it can potentially identify a taxon as a desirable component of an ecosystem or target it for removal. In some cases, however, such background information is inadequate or unavailable. Here we use paleo-DNA to re-evaluate the historical status of yellow perch in the 6 million acre Adirondack State Park of northern New York. Yellow perch DNA in a 2200-year sediment record reveals a long-term native status for these supposedly alien fish and challenges assumptions that they necessarily exclude native trout from upland lakes. Similar approaches could be applied to other species with uncertain historical distributions and could help to identify unrecognized pockets of biodiversity. PMID:25751263

  17. Of paleo-genes and Perch: what if an "alien" is actually a native?

    PubMed

    Stager, J Curt; Sporn, Lee Ann; Johnson, Melanie; Regalado, Sean

    2015-01-01

    Documenting whether a biotic taxon is native or alien to an ecosystem has theoretical value for ecological and evolutionary studies, and has practical value because it can potentially identify a taxon as a desirable component of an ecosystem or target it for removal. In some cases, however, such background information is inadequate or unavailable. Here we use paleo-DNA to re-evaluate the historical status of yellow perch in the 6 million acre Adirondack State Park of northern New York. Yellow perch DNA in a 2200-year sediment record reveals a long-term native status for these supposedly alien fish and challenges assumptions that they necessarily exclude native trout from upland lakes. Similar approaches could be applied to other species with uncertain historical distributions and could help to identify unrecognized pockets of biodiversity.

  18. Retention of mercury in the muscle of yellow perch (Perca flavescens) and rock bass (Ambloplites rupestris)

    USGS Publications Warehouse

    Laarman, Percy W.; Willford, Wayne A.; Olson, James R.

    1976-01-01

    Mercury-contaminated yellow perch (Perca flavescens) and rock bass (Ambloplites rupestris) were collected from Lake St. Clair and stocked in two earthen ponds in September 1970. Twenty-six months later, concentrations of total mercury in the fillets had declined 53% in the yellow perch and 59% in the rock bass; however, the mean weight of the fish increased 88 and 183%, respectively, during the same period. All of the reduction in mercury concentrations was attributable to dilution by growth. Slight discrepancies between the theoretical and observed reduction of mercury concentrations suggest an initial redistribution of residues from other tissues to the muscle and a continued incorporation of background amounts of mercury during growth.

  19. Exclusion of copper from altered hepatocytes in white perch (Morone americana) with hepatic copper storage.

    PubMed

    Bunton, T E

    1995-01-01

    Iron is excluded from foci of hepatocellular alteration in carcinogenesis of rodents and some fish. Among white perch (Morone americana), there is a condition of hepatic copper storage in which copper-loaded livers are produced naturally. In a group of fish collected from the Chesapeake Bay, Maryland (USA), from September to December 1990, we observed hepatic lesions which excluded copper similar to the phenomenon of iron exclusion, in a white perch with over 3,600 micrograms/g wet weight hepatic copper. The lesions were of two types: one with cells morphologically different from normal hepatocytes and which had diminished to absolute exclusion of copper with the copper specific histochemical stain rubeinic acid, and a second with cells morphologically similar to normal hepatocytes which had only a partial exclusion of copper. Although the exact cause and nature of the lesions was not determined, intrinsic copper toxicity, environmental pollution, or a combination of these factors may have contributed to their development.

  20. Modeling turbidity type and intensity effects on the growth and starvation mortality of age-0 yellow perch

    USGS Publications Warehouse

    Manning, Nathan M; Bossenbroek, Jonathan M.; Mayer, Christine M.; Bunnell, David B.; Tyson, Jeff T.; Rudstam, Lars G.; Jackson, James R.

    2014-01-01

    We sought to quantify the possible population-level influence of sediment plumes and algal blooms on yellow perch (Perca flavescens), a visual predator found in systems with dynamic water clarity. We used an individual-based model (IBM), which allowed us to include variance in water clarity and the distribution of individual sizes. Our IBM was built with laboratory data showing that larval yellow perch feeding rates increased slightly as sediment turbidity level increased, but that both larval and juvenile yellow perch feeding rates decreased as phytoplankton level increased. Our IBM explained a majority of the variance in yellow perch length in data from the western and central basins of Lake Erie and Oneida Lake, with R2 values ranging from 0.611 to 0.742. Starvation mortality was size dependent, as the greatest daily mortality rates in each simulation occurred within days of each other. Our model showed that turbidity-dependent consumption rates and temperature are key components in determining growth and starvation mortality of age-0 yellow perch, linking fish production to land-based processes that influence water clarity. These results suggest the timing and persistence of sediment plumes and algal blooms can drastically alter the growth potential and starvation mortality of a yellow perch cohort.

  1. Effects of habitat on mercury concentrations in fish: a case study of Nile perch (Lates niloticus) in Lake Nabugabo, Uganda.

    PubMed

    Hanna, D E L; Buck, D G; Chapman, L J

    2016-01-01

    This study focused on variation in fish mercury (Hg) concentrations in 185 Nile perch (Lates niloticus) samples collected across four different habitat types in Lake Nabugabo, Uganda, a tropical lake located proximate to Lake Victoria. We quantified the stomach contents of Nile perch using the % index of relative importance, as well as, nitrogen and carbon isotopic concentrations to assess the role of diet and trophic level on Hg concentrations. In each habitat, we also evaluated a suite of chemical and physical characteristics that are commonly associated with variation in Hg bioavailability in temperate systems. Using linear mixed models and ANOVA, we demonstrate that habitat of capture is an important predictor of Hg concentrations in Nile perch from Lake Nabugabo and that the relationship between habitat and Hg is size and diet dependent. Nile perch diet as well as dissolved oxygen concentration and pH were also correlated with observed differences in fish Hg. Overall, Hg concentrations in Nile perch were all well below the WHO/FAO recommended guideline of 500 ng/g (mean 13.6 ± 0.4 ng/g wet weight; range 4.9 and 29.3 ng/g wet weight). This work contributes to a growing awareness of intra-lake divergence in Nile perch, as well as, divergence in Hg concentrations between varying aquatic habitat types, particularly wetlands.

  2. Echolocation intensity and directionality of perching and flying fringe-lipped bats, Trachops cirrhosus (Phyllostomidae).

    PubMed

    Surlykke, Annemarie; Jakobsen, Lasse; Kalko, Elisabeth K V; Page, Rachel A

    2013-01-01

    The Neotropical frog-eating bat, Trachops cirrhosus, primarily hunts stationary prey, either by gleaning on the wing, or in a sit-and-wait mode hanging from a perch. It listens passively for prey-generated sounds, but uses echolocation in all stages of the hunt. Like other bats in the family Phyllostomidae, T. cirrhosus has a conspicuous nose leaf, hypothesized to direct and focus echolocation calls emitted from the nostrils. T. cirrhosus is highly flexible in its cognitive abilities and its use of sensory strategies for prey detection. Additionally, T. cirrhosus has been observed to echolocate both with closed and open mouth. We hypothesize that its flexibility extends to echolocation call design. We investigated the effect of hunting mode, perching or flying, as well as the effect of mouth opening, on the acoustic parameters and directionality of the echolocation call. We used a multi-microphone array, a high-speed video camera, and a microphone-diode-video system to directly visualize the echolocation sound beam synchronized with the bat's behavior. We found that T. cirrhosus emits a highly directional sound beam with half amplitude angle (HAM) of 12-18° and DI (directionality index) of ~17 dB, among the most directional bat sonar beams measured to date. The directionality was high both when flying and when perching. The emitted intensity was low, around 88 dB SPL at 10 cm from the mouth, when hanging, but higher, around 100 dB SPL at 10 cm, when flying or just before take-off. Our data suggests that the limited search volume of T. cirrhosus sonar beam defined by the high directionality and the rather low intensity of its echolocation calls is adapted to the highly cluttered hunting habitat and to the perch hunting mode.

  3. Evaluation of daily creel and minimum length limits for Black Crappies and Yellow Perch in Wisconsin

    USGS Publications Warehouse

    Mosel, Kyle; Isermann, Daniel A.; Hansen, Jonathan F.

    2015-01-01

    Harvest regulations for Black Crappie Pomoxis nigromaculatus and Yellow Perch Perca flavescens in the northern USA and Canada have not been thoroughly evaluated, and specific guidance regarding where minimum length limits (MLLs) might improve these fisheries is lacking. We examined whether: (1) transitioning from an aggregate statewide daily creel limit of 25 panfish to species-specific daily creel limits of <25 fish or implementing statewide MLLs could reduce harvest of Black Crappie and Yellow Perch in Wisconsin by ≥25%, and (2) MLLs would improve yield by ≥10% and mean TL of harvested fish by ≥25 mm in Wisconsin fisheries. Creel surveys indicated that ≥94% of Wisconsin anglers did not harvest a Black Crappie or Yellow Perch, and ≤0.12% of anglers harvested a daily creel limit of 25 fish. Daily creel limits would need to be ≤7 fish/ angler to reduce harvest by ≥25%. Statewide MLLs would need to be ≥229 mm for Black Crappie and ≥203 mm for Yellow Perch to reduce harvest by ≥25%, but predicted responses to MLLs varied among simulated populations. In general, MLLs were not predicted to improve yield, indicating that growth overfishing was not a widespread problem. Minimum length limits could improve mean TL of harvested fish, but increases ≥25 mm were only observed under 254-mm and 279-mm MLLs, and anglers would have to accept predicted reductions in harvest of ≥30% to achieve these improvements. A 229-mm MLL offered a more equitable trade-off between increases in mean TLs of harvested fish (11–21-mm improvements) and reductions in harvest (22–37% reductions). Our modeling provides a framework for managers to make more informed decisions regarding harvest regulations, but more information regarding angler preferences is needed for selecting appropriate management objectives and harvest regulations.

  4. Movements of yellow perch marked in southern Green Bay, Lake Michigan, in 1950

    USGS Publications Warehouse

    Mraz, Donald

    1952-01-01

    These investigations have demonstrated that for studying migration of yellow perch, tagging is superior to fin-clipping as a method of marking. The technique of the tagging, however, needs to be improved, and better means must be found to trace tagged fish of small size. Furthermore certain small regions in the bay not at present open to commercial fishing must be explored in order to obtain more comprehensive information as to migration.

  5. Echolocation intensity and directionality of perching and flying fringe-lipped bats, Trachops cirrhosus (Phyllostomidae)

    PubMed Central

    Surlykke, Annemarie; Jakobsen, Lasse; Kalko, Elisabeth K. V.; Page, Rachel A.

    2013-01-01

    The Neotropical frog-eating bat, Trachops cirrhosus, primarily hunts stationary prey, either by gleaning on the wing, or in a sit-and-wait mode hanging from a perch. It listens passively for prey-generated sounds, but uses echolocation in all stages of the hunt. Like other bats in the family Phyllostomidae, T. cirrhosus has a conspicuous nose leaf, hypothesized to direct and focus echolocation calls emitted from the nostrils. T. cirrhosus is highly flexible in its cognitive abilities and its use of sensory strategies for prey detection. Additionally, T. cirrhosus has been observed to echolocate both with closed and open mouth. We hypothesize that its flexibility extends to echolocation call design. We investigated the effect of hunting mode, perching or flying, as well as the effect of mouth opening, on the acoustic parameters and directionality of the echolocation call. We used a multi-microphone array, a high-speed video camera, and a microphone-diode-video system to directly visualize the echolocation sound beam synchronized with the bat's behavior. We found that T. cirrhosus emits a highly directional sound beam with half amplitude angle (HAM) of 12–18° and DI (directionality index) of ~17 dB, among the most directional bat sonar beams measured to date. The directionality was high both when flying and when perching. The emitted intensity was low, around 88 dB SPL at 10 cm from the mouth, when hanging, but higher, around 100 dB SPL at 10 cm, when flying or just before take-off. Our data suggests that the limited search volume of T. cirrhosus sonar beam defined by the high directionality and the rather low intensity of its echolocation calls is adapted to the highly cluttered hunting habitat and to the perch hunting mode. PMID:23825459

  6. Dermal melanin concentration of yellow perch Perca flavescens in relation to water transparency.

    PubMed

    Rheault, G; Langevin, M; Cabana, G; Glémet, H

    2015-11-01

    A positive relationship was observed between Secchi disc depth and dermal melanin concentration in yellow perch Perca flavescens sampled from 11 humic lakes located on the Canadian Shield in southern Quebec (Canada). Secchi disc depth explained 23% of the variations of dermal melanin concentration. Secchi disc depth and thus water transparency appear to have a positive influence on melanin production in the dermis of P. flavescens.

  7. Standardization of Clinical Assessment and Sample Collection Across All PERCH Study Sites.

    PubMed

    Crawley, Jane; Prosperi, Christine; Baggett, Henry C; Brooks, W Abdullah; Deloria Knoll, Maria; Hammitt, Laura L; Howie, Stephen R C; Kotloff, Karen L; Levine, Orin S; Madhi, Shabir A; Murdoch, David R; O'Brien, Katherine L; Thea, Donald M; Awori, Juliet O; Bunthi, Charatdao; DeLuca, Andrea N; Driscoll, Amanda J; Ebruke, Bernard E; Goswami, Doli; Hidgon, Melissa M; Karron, Ruth A; Kazungu, Sidi; Kourouma, Nana; Mackenzie, Grant; Moore, David P; Mudau, Azwifari; Mwale, Magdalene; Nahar, Kamrun; Park, Daniel E; Piralam, Barameht; Seidenberg, Phil; Sylla, Mamadou; Feikin, Daniel R; Scott, J Anthony G

    2017-06-15

    Variable adherence to standardized case definitions, clinical procedures, specimen collection techniques, and laboratory methods has complicated the interpretation of previous multicenter pneumonia etiology studies. To circumvent these problems, a program of clinical standardization was embedded in the Pneumonia Etiology Research for Child Health (PERCH) study. Between March 2011 and August 2013, standardized training on the PERCH case definition, clinical procedures, and collection of laboratory specimens was delivered to 331 clinical staff at 9 study sites in 7 countries (The Gambia, Kenya, Mali, South Africa, Zambia, Thailand, and Bangladesh), through 32 on-site courses and a training website. Staff competency was assessed throughout 24 months of enrollment with multiple-choice question (MCQ) examinations, a video quiz, and checklist evaluations of practical skills. MCQ evaluation was confined to 158 clinical staff members who enrolled PERCH cases and controls, with scores obtained for >86% of eligible staff at each time-point. Median scores after baseline training were ≥80%, and improved by 10 percentage points with refresher training, with no significant intersite differences. Percentage agreement with the clinical trainer on the presence or absence of clinical signs on video clips was high (≥89%), with interobserver concordance being substantial to high (AC1 statistic, 0.62-0.82) for 5 of 6 signs assessed. Staff attained median scores of >90% in checklist evaluations of practical skills. Satisfactory clinical standardization was achieved within and across all PERCH sites, providing reassurance that any etiological or clinical differences observed across the study sites are true differences, and not attributable to differences in application of the clinical case definition, interpretation of clinical signs, or in techniques used for clinical measurements or specimen collection.

  8. Using consumption rate to assess potential predators for biological control of white perch

    USGS Publications Warehouse

    Gosch, N.J.C.; Pope, K.L.

    2011-01-01

    Control of undesirable fishes is important in aquatic systems, and using predation as a tool for biological control is an attractive option to fishery biologists. However, determining the appropriate predators for biological control is critical for success. The objective of this study was to evaluate the utility of consumption rate as an index to determine the most effective predators for biological control of an invasive fish. Consumption rate values were calculated for nine potential predators that prey on white perch Morone americana in Branched Oak and Pawnee reservoirs, Nebraska. The consumption rate index provided a unique and insightful means of determining the potential effectiveness of each predator species in controlling white perch. Cumulative frequency distributions facilitated interpretation by providing a graphical presentation of consumption rates by all individuals within each predator species. Largemouth bass Micropterus salmoides, walleye Sander vitreus and sauger S. canadensis were the most efficient white perch predators in both reservoirs; however, previous attempts to increase biomass of these predators have failed suggesting that successful biological control is unlikely using existing predator species in these Nebraska reservoirs. ?? 2011 ONEMA.

  9. Minimum size limits for yellow perch (Perca flavescens) in western Lake Erie

    USGS Publications Warehouse

    Hartman, Wilbur L.; Nepszy, Stephen J.; Scholl, Russell L.

    1980-01-01

    During the 1960's yellow perch (Perca flavescens) of Lake Erie supported a commercial fishery that produced an average annual catch of 23 million pounds, as well as a modest sport fishery. Since 1969, the resource has seriously deteriorated. Commercial landings amounted to only 6 million pounds in 1976, and included proportionally more immature perch than in the 1960's. Moreover, no strong year classes were produced between 1965 and 1975. An interagency technical committee was appointed in 1975 by the Lake Erie Committee of the Great Lakes Fishery Commission to develop an interim management strategy that would provide for greater protection of perch in western Lake Erie, where declines have been the most severe. The committee first determined the age structure, growth and mortality rates, maturation schedule, and length-fecundity relationship for the population, and then applied Ricker-type equilibrium yield models to determine the effects of various minimum length limits on yield, production, average stock weight, potential egg deposition, and the Abrosov spawning frequency indicator (average number of spawning opportunities per female). The committee recommended increasing the minimum length limit of 5.0 inches to at least 8.5 inches. Theoretically, this change would increase the average stock weight by 36% and potential egg deposition by 44%, without significantly decreasing yield. Abrosov's spawning frequency indicator would rise from the existing 0.6 to about 1.2.

  10. Dietary calcein marking of brook trout, Atlantic salmon, yellow perch, and coho salmon scales

    USGS Publications Warehouse

    Honeyfield, D.C.; Ostrowski, C.S.; Fletcher, J.W.; Mohler, J.W.

    2006-01-01

    Brook trout Salvelinus fontinalis, Atlantic salmon Salmo salar, coho salmon Oncorhynchus kisutch, and yellow perch Perca flavescens fed calcein for 5 d showed characteristic calcein scale marks 7-10 d postmarking. In fish fed 0.75 or 1.25 g of calcein per kilogram of feed, the percentage of fish that exhibited a calcein mark was 100% in brook trout, 93-98% in Atlantic salmon, 60% in yellow perch, and 0% in coho salmon. However, when coho salmon were fed 5.25 g calcein/kg feed, 100% marking was observed 7-10 d postmarking. Brook trout were successfully marked twice with distinct bands when fed calcein 5 months apart. Brook trout scale pixel luminosity increased as dietary calcein increased in experiment 2. For the second calcein mark, scale pixel luminosity from brook trout fed 1.25 g calcein/kg feed was numerically higher (P < 0.08) than scales from fish fed 0.75 g calcein/kg feed. Mean pixel luminosity of calcein-marked Atlantic salmon scales was 57.7 for fish fed 0.75 g calcein/kg feed and 55.2 for fish fed 1.25 g calcein/kg feed. Although feed acceptance presented a problem in yellow perch, these experiments provide evidence that dietary calcein is a viable tool for marking fish for stock identification. ?? Copyright by the American Fisheries Society 2006.

  11. Rapid area change in pitch-up manoeuvres of small perching birds.

    PubMed

    Polet, D T; Rival, D E

    2015-10-26

    Rapid pitch-up has been highlighted as a mechanism to generate large lift and drag during landing manoeuvres. However, pitching rates had not been measured previously in perching birds, and so the direct applicability of computations and experiments to observed behaviour was not known. We measure pitch rates in a small, wild bird (the black-capped chickadee; Poecile atricapillus), and show that these rates are within the parameter range used in experiments. Pitching rates were characterized by the shape change number, a metric comparing the rate of frontal area increase to acceleration. Black-capped chickadees increase the shape change number during perching in direct proportion to their total kinetic and potential energy at the start of the manoeuvre. The linear relationship between dissipated energy and shape change number is in accordance with a simple analytical model developed for two-dimensional pitching and decelerating airfoils. Black-capped chickadees use a wing pitch-up manoeuvre during perching to dissipate energy quickly while maintaining lift and drag through rapid area change. It is suggested that similar pitch-and-decelerate manoeuvres could be used to aid in the controlled, precise landings of small manoeuvrable air vehicles.

  12. Preferential flow, diffuse flow, and perching in an interbedded fractured-rock unsaturated zone

    USGS Publications Warehouse

    Nimmo, John R.; Creasey, Kaitlyn M; Perkins, Kimberlie; Mirus, Benjamin B.

    2017-01-01

    Layers of strong geologic contrast within the unsaturated zone can control recharge and contaminant transport to underlying aquifers. Slow diffuse flow in certain geologic layers, and rapid preferential flow in others, complicates the prediction of vertical and lateral fluxes. A simple model is presented, designed to use limited geological site information to predict these critical subsurface processes in response to a sustained infiltration source. The model is developed and tested using site-specific information from the Idaho National Laboratory in the Eastern Snake River Plain (ESRP), USA, where there are natural and anthropogenic sources of high-volume infiltration from floods, spills, leaks, wastewater disposal, retention ponds, and hydrologic field experiments. The thick unsaturated zone overlying the ESRP aquifer is a good example of a sharply stratified unsaturated zone. Sedimentary interbeds are interspersed between massive and fractured basalt units. The combination of surficial sediments, basalts, and interbeds determines the water fluxes through the variably saturated subsurface. Interbeds are generally less conductive, sometimes causing perched water to collect above them. The model successfully predicts the volume and extent of perching and approximates vertical travel times during events that generate high fluxes from the land surface. These developments are applicable to sites having a thick, geologically complex unsaturated zone of substantial thickness in which preferential and diffuse flow, and perching of percolated water, are important to contaminant transport or aquifer recharge.

  13. Individual-based model of yellow perch and walleye populations in Oneida Lake

    SciTech Connect

    Rose, K.A.; Rutherford, E.S.; McDermot, D.S.; Forney, J.L.; Mills, E.L.

    1999-05-01

    Predator-prey dynamics and density dependence are fundamental issues in ecology. The authors use a detailed, individual-based model of walleye and yellow perch to investigate the effects of alternative prey and compensatory responses on predator and prey population dynamics. The analyses focus on the numerical and developmental responses of the predator, rather than the traditional emphasis on functional responses. The extensive database for Oneida Lake, New York, USA was used to configure the model and ensure its realism. The model follows the daily growth, mortality, and spawning of individuals of each species through their lifetime. Three ecologically distinct periods in the history of Oneida Lake were simulated: baseline, high mayfly densities, and high forage fish densities. Mayflies and forage fish act as alternative prey for walleye. For model corroboration, the three periods were simulated sequentially as they occurred in Oneida Lake. Model predictions of abundances, size at age, and growth and survival rates compared favorably with Oneida Lake data. Three hypotheses suggested by the data were evaluated: alternative prey stabilizes yellow perch and walleye populations; alternative prey increases yellow perch and walleye recruitment; and density-dependent growth and survival compensate for changes in young-of-the-year mortality. Model simulations were performed under increased mayfly densities, increased forage fish densities, and increased egg mortality rates.

  14. Preferential flow, diffuse flow, and perching in an interbedded fractured-rock unsaturated zone

    NASA Astrophysics Data System (ADS)

    Nimmo, John R.; Creasey, Kaitlyn M.; Perkins, Kim S.; Mirus, Benjamin B.

    2016-11-01

    Layers of strong geologic contrast within the unsaturated zone can control recharge and contaminant transport to underlying aquifers. Slow diffuse flow in certain geologic layers, and rapid preferential flow in others, complicates the prediction of vertical and lateral fluxes. A simple model is presented, designed to use limited geological site information to predict these critical subsurface processes in response to a sustained infiltration source. The model is developed and tested using site-specific information from the Idaho National Laboratory in the Eastern Snake River Plain (ESRP), USA, where there are natural and anthropogenic sources of high-volume infiltration from floods, spills, leaks, wastewater disposal, retention ponds, and hydrologic field experiments. The thick unsaturated zone overlying the ESRP aquifer is a good example of a sharply stratified unsaturated zone. Sedimentary interbeds are interspersed between massive and fractured basalt units. The combination of surficial sediments, basalts, and interbeds determines the water fluxes through the variably saturated subsurface. Interbeds are generally less conductive, sometimes causing perched water to collect above them. The model successfully predicts the volume and extent of perching and approximates vertical travel times during events that generate high fluxes from the land surface. These developments are applicable to sites having a thick, geologically complex unsaturated zone of substantial thickness in which preferential and diffuse flow, and perching of percolated water, are important to contaminant transport or aquifer recharge.

  15. Compartment proteomics analysis of white perch (Morone americana) ovary using support vector machines.

    PubMed

    Schilling, Justin; Nepomuceno, Angelito; Schaff, Jennifer E; Muddiman, David C; Daniels, Harry V; Reading, Benjamin J

    2014-03-07

    Compartment proteomics enable broad characterization of target tissues. We employed a simple fractionation method and filter-aided sample preparation (FASP) to characterize the cytosolic and membrane fractions of white perch ovary tissues by semiquantitative tandem mass spectrometry using label-free quantitation based on normalized spectral counts. FASP depletes both low-molecular-weight and high-molecular-weight substances that could interfere with protein digestion and subsequent peptide separation and detection. Membrane proteins are notoriously difficult to characterize due to their amphipathic nature and association with lipids. The simple fractionation we employed effectively revealed an abundance of proteins from mitochondria and other membrane-bounded organelles. We further demonstrate that support vector machines (SVMs) offer categorical classification of proteomics data superior to that of parametric statistical methods such as analysis of variance (ANOVA). Specifically, SVMs were able to perfectly (100% correct) classify samples as either membrane or cytosolic fraction during cross-validation based on the expression of 242 proteins with the highest ANOVA p-values (i.e., those that were not significant for enrichment in either fraction). The white perch ovary cytosolic and membrane proteomes and transcriptome presented in this study can support future investigations into oogenesis and early embryogenesis of white perch and other members of the genus Morone.

  16. Comparison of nutritional quality in fish maw product of croaker Protonibea diacanthus and perch Lates niloticus

    NASA Astrophysics Data System (ADS)

    Wen, Jing; Zeng, Ling; Chen, Ziming; Xu, Youhou

    2016-08-01

    Fish maw (the dried swimbladders of fish) is ranked in the list of the four sea treasures in Chinese cuisine. Fish maw is mainly produced from croaker, which is the most highly priced. However, some of the fish maw being sold as croaker maw are in fact not from croaker, but from the Nile perch Lates niloticus. The present work determined and compared the proximate composition, amino acid and fatty acid composition of croaker Protonibea diacanthus maw and perch L. niloticus maw. The results indicated that both maws were high protein sources and low in fat content. The dominant amino acids in both maws were glycine, proline, glutamic acid, alanine and arginine. These amino acids constituted 66.2% and 66.4% of the total amino acids in P. diacanthus and L. niloticus, respectively. The ratio of FAA: TAA (functional amino acids: total amino acids) in both maws were 0.69. This is a good explanation for why fish maws have been widely utilized as a traditional tonic and remedy in Asia. Except valine and histidine, all the essential amino acid contents in P. diacanthus were higher than in L. niloticus. Moreover, croaker P. diacanthus maw contained more AA and DHA than perch L. niloticus maw, showing a higher ratio of n-3 / n-6, which is more desirable.

  17. Enhancing effect of spawning on elimination of a persistent polychlorinated biphenyl from female yellow perch

    SciTech Connect

    Vodicnik, M.J.; Peterson, R.E.

    1985-08-01

    Distribution and elimination of 2,5,2',5'-tetrachloro(14C)biphenyl (4-CB) were studied for 6 months after exposing sexually mature female yellow perch to the compound in water and transferring them to flowing 4-CB-free water. Perch that were exposed in January spawned in May, and the study was terminated in June. During the first 41/2 months after exposure, the t1/2 for whole-body elimination was 22 weeks, primarily by elimination of 4-CB from the viscera and carcass. During spawning, enhanced elimination (t1/2 less than 0.7 weeks) was due to the voiding of eggs containing 4-CB. After spawning, whole-body elimination returned to a slower rate (t1/2 = 16.3 weeks). Prior to the enhancement in 4-CB elimination rate during spawning, there was a redistribution of 4-CB residues within the body of the perch which was characterized by a transfer of 4-CB residues from primarily the carcass and viscera to eggs. Two weeks after exposure, 30% of the initial 4-CB body burden was distributed to the eggs, whereas just prior to spawning, about 50% was present in this tissue. These findings demonstrate that egg maturation and spawning result in a significant reduction in the body burden of a persistent polychlorinated biphenyl in a lean-fish species.

  18. Are high perches in the blackcap Sylvia atricapilla song or listening posts? A sound transmission study

    NASA Astrophysics Data System (ADS)

    Mathevon, Nicolas; Dabelsteen, Torben; Blumenrath, Sandra H.

    2005-01-01

    Birds often sing from high perches referred to as song posts. However, birds also listen and keep a lookout from these perches. We used a sound transmission experiment to investigate the changes for receiving and sending conditions that a territorial songbird may experience by moving upwards in the vegetation. Representative song elements of the blackcap Sylvia atricapilla were transmitted in a forest habitat in spring using a complete factorial design with natural transmission distances and speaker and microphone heights. Four aspects of sound degradation were quantified: signal-to-noise ratio, excess attenuation, distortion within the sounds determined as a blur ratio, and prolongation of the sounds with ``tails'' of echoes determined as a tail-to-signal ratio. All four measures indicated that degradation decreased with speaker and microphone height. However, the decrease was considerably higher for the microphone than for the speaker. This suggests that choosing high perches in a forest at spring results in more benefits to blackcaps in terms of improved communication conditions when they act as receivers than as senders. .

  19. Preferential flow, diffuse flow, and perching in an interbedded fractured-rock unsaturated zone

    NASA Astrophysics Data System (ADS)

    Nimmo, John R.; Creasey, Kaitlyn M.; Perkins, Kim S.; Mirus, Benjamin B.

    2017-03-01

    Layers of strong geologic contrast within the unsaturated zone can control recharge and contaminant transport to underlying aquifers. Slow diffuse flow in certain geologic layers, and rapid preferential flow in others, complicates the prediction of vertical and lateral fluxes. A simple model is presented, designed to use limited geological site information to predict these critical subsurface processes in response to a sustained infiltration source. The model is developed and tested using site-specific information from the Idaho National Laboratory in the Eastern Snake River Plain (ESRP), USA, where there are natural and anthropogenic sources of high-volume infiltration from floods, spills, leaks, wastewater disposal, retention ponds, and hydrologic field experiments. The thick unsaturated zone overlying the ESRP aquifer is a good example of a sharply stratified unsaturated zone. Sedimentary interbeds are interspersed between massive and fractured basalt units. The combination of surficial sediments, basalts, and interbeds determines the water fluxes through the variably saturated subsurface. Interbeds are generally less conductive, sometimes causing perched water to collect above them. The model successfully predicts the volume and extent of perching and approximates vertical travel times during events that generate high fluxes from the land surface. These developments are applicable to sites having a thick, geologically complex unsaturated zone of substantial thickness in which preferential and diffuse flow, and perching of percolated water, are important to contaminant transport or aquifer recharge.

  20. Estimation of genotyping error rate from repeat genotyping, unintentional recaptures and known parent-offspring comparisons in 16 microsatellite loci for brown rockfish (Sebastes auriculatus).

    PubMed

    Hess, Maureen A; Rhydderch, James G; LeClair, Larry L; Buckley, Raymond M; Kawase, Mitsuhiro; Hauser, Lorenz

    2012-11-01

    Genotyping errors are present in almost all genetic data and can affect biological conclusions of a study, particularly for studies based on individual identification and parentage. Many statistical approaches can incorporate genotyping errors, but usually need accurate estimates of error rates. Here, we used a new microsatellite data set developed for brown rockfish (Sebastes auriculatus) to estimate genotyping error using three approaches: (i) repeat genotyping 5% of samples, (ii) comparing unintentionally recaptured individuals and (iii) Mendelian inheritance error checking for known parent-offspring pairs. In each data set, we quantified genotyping error rate per allele due to allele drop-out and false alleles. Genotyping error rate per locus revealed an average overall genotyping error rate by direct count of 0.3%, 1.5% and 1.7% (0.002, 0.007 and 0.008 per allele error rate) from replicate genotypes, known parent-offspring pairs and unintentionally recaptured individuals, respectively. By direct-count error estimates, the recapture and known parent-offspring data sets revealed an error rate four times greater than estimated using repeat genotypes. There was no evidence of correlation between error rates and locus variability for all three data sets, and errors appeared to occur randomly over loci in the repeat genotypes, but not in recaptures and parent-offspring comparisons. Furthermore, there was no correlation in locus-specific error rates between any two of the three data sets. Our data suggest that repeat genotyping may underestimate true error rates and may not estimate locus-specific error rates accurately. We therefore suggest using methods for error estimation that correspond to the overall aim of the study (e.g. known parent-offspring comparisons in parentage studies).

  1. A teleostan homolog of catalase from black rockfish (Sebastes schlegelii): insights into functional roles in host antioxidant defense and expressional responses to septic conditions.

    PubMed

    Elvitigala, Don Anushka Sandaruwan; Priyathilaka, Thanthrige Thiunuwan; Whang, Ilson; Nam, Bo-Hye; Lee, Jehee

    2015-05-01

    Antioxidative defense renders a significant protection against environmental stress in organisms and maintains the correct redox balance in cells, thereby supporting proper immune function. Catalase is an indispensable antioxidant in organisms that detoxifies hydrogen peroxides produced in cellular environments. In this study, we sought to molecularly characterize a homolog of catalase (RfCat), identified from black rockfish (Sebastes schlegelii). RfCat consists of a 1581 bp coding region for a protein of 527 amino acids, with a predicted molecular weight of 60 kD. The protein sequence of RfCat harbored similar domain architecture to known catalases, containing a proximal active site signature and proximal heme ligand signature, and further sharing prominent homology with its teleostan counterparts. As affirmed by multiple sequence alignments, most of the functionally important residues were well conserved in RfCat. Furthermore, our phylogenetic analysis indicates its common vertebrate ancestral origin and a close evolutionary relationship with teleostan catalases. Recombinantly expressed RfCat demonstrated prominent peroxidase activity that varied with different substrate and protein concentrations, and protected against DNA damage. RfCat mRNA was ubiquitously expressed among different tissues examined, as detected by qPCR. In addition, RfCat mRNA expression was modulated in response to pathogenic stress elicited by Streptococcus iniae and poly I:C in blood and spleen tissues. Collectively, our findings indicate that RfCat may play an indispensable role in host response to oxidative stress and maintain a correct redox balance after a pathogen invasion.

  2. Mechanisms of Egg Yolk Formation and Implications on Early Life History of White Perch (Morone americana)

    PubMed Central

    Schilling, Justin; Loziuk, Philip L.; Muddiman, David C.; Daniels, Harry V.; Reading, Benjamin J.

    2015-01-01

    The three white perch (Morone americana) vitellogenins (VtgAa, VtgAb, VtgC) were quantified accurately and precisely in the liver, plasma, and ovary during pre-, early-, mid-, and post-vitellogenic oocyte growth using protein cleavage-isotope dilution mass spectrometry (PC-IDMS). Western blotting generally mirrored the PC-IDMS results. By PC-IDMS, VtgC was quantifiable in pre-vitellogenic ovary tissues and VtgAb was quantifiable in pre-vitellogenic liver tissues however, neither protein was detected by western blotting in these respective tissues at this time point. Immunohistochemistry indicated that VtgC was present within pre-vitellogenic oocytes and localized to lipid droplets within vitellogenic oocytes. Affinity purification coupled to tandem mass spectrometry using highly purified VtgC as a bait protein revealed a single specific interacting protein (Y-box binding protein 2a-like [Ybx2a-like]) that eluted with suramin buffer and confirmed that VtgC does not bind the ovary vitellogenin receptors (LR8 and Lrp13). Western blotting for LR8 and Lrp13 showed that both receptors were expressed during vitellogenesis with LR8 and Lrp13 expression highest in early- and mid-vitellogenesis, respectively. The VtgAa within the ovary peaked during post-vitellogenesis, while VtgAb peaked during early-vitellogenesis in both white perch and the closely related striped bass (M. saxatilis). The VtgC was steadily accumulated by oocytes beginning during pre-vitellogenesis and continued until post-vitellogenesis and its composition varies widely between striped bass and white perch. In striped bass, the VtgC accounted for 26% of the vitellogenin-derived egg yolk, however in the white perch it comprised only 4%. Striped bass larvae have an extended developmental window and these larvae have yolk stores that may enable them to survive in the absence of food for twice as long as white perch after hatch. Thus, the VtgC may play an integral role in providing nutrients to late stage

  3. Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest). Pile Perch, Striped Seaperch, and Rubberlip Seaperch

    DTIC Science & Technology

    1989-07-01

    indicated that pile perch were con- 1975 114 40 sistent predators on intertidal snails 1976 142 57 in British Columbia; they also ate barnacles , small crabs...35 large pile perch because it supported 1969 ib6 36 few barnacles and no mussels. Wares 1970 241 43 (1971) listed six phyla in the diet at 1971 185 43...the same area. Striped seaperch prefer shallow water (< 6 m) even when black perch are removed from deeper water. Both species are substrate feeders

  4. Decrease of Population Divergence in Eurasian Perch (Perca fluviatilis) in Browning Waters: Role of Fatty Acids and Foraging Efficiency.

    PubMed

    Scharnweber, Kristin; Strandberg, Ursula; Karlsson, Konrad; Eklöv, Peter

    2016-01-01

    Due to altered biogeochemical processes related to climate change, highly colored dissolved organic carbon (DOC) from terrestrial sources will lead to a water "brownification" in many freshwater systems of the Northern Hemisphere. This will create deteriorated visual conditions that have been found to affect habitat-specific morphological variations in Eurasian perch (Perca fluviatilis) in a previous study. So far, potential drivers and ultimate causes of these findings have not been identified. We conducted a field study to investigate the connection between morphological divergence and polyunsaturated fatty acid (PUFA) composition of perch from six lakes across a gradient of DOC concentration. We expected a decrease in the prevalence of PUFAs, which are important for perch growth and divergence with increasing DOC concentrations, due to the restructuring effects of DOC on aquatic food webs. In general, rate of morphological divergence in perch decreased with increasing DOC concentrations. Proportions of specific PUFAs (22:6n-3, 18:3n-3, 20:5n-3, and 20:4n-6) identified to primarily contribute to overall differences between perch caught in clear and brown-water lakes tended to be connected to overall decline of morphological divergence. However, no overall significant relationship was found, indicating no severe limitation of essential fatty acids for perch inhabiting brown water lakes. We further broaden our approach by conducting a laboratory experiment on foraging efficiency of perch. Therefore, we induced pelagic and littoral phenotypes by differences in habitat-structure and feeding mode and recorded attack rate in a feeding experiment. Generally, fish were less efficient in foraging on littoral prey (Ephemeroptera) when visual conditions were degraded by brown water color. We concluded that browning water may have a strong effect on the forager's ability to find particular food resources, resulting in the reduced development of evolutionary traits, such as

  5. Escape tactics and effects of perch height and habituation on flight initiation distance in two Jamaican anoles (Squamata: polychrotidae).

    PubMed

    Cooper, William E

    2010-12-01

    Escape by Anolis lizards is influenced by microhabitats and fight initiation distance increases with predation risk. Differences in microhabitat use among ecomorphs affect escape behavior, but only two studies have reported ecomorphological differences in flight initiation distance among Greater Antillean species. I studied effects of predation risk and microhabitats on escape behavior by conducting field experiments using two species of anoles, Anolis lineatopus and A. grahami, on the campus of the University of the West Indies at Mona, Jamaica. Because ecomorphological variation of anoles has evolved independently within each island of the Greater Antilles, but relationships between ecomorphs and escape behaviors are poorly known, I characterized microhabitat use and escape tactics, and determined relationships between flight initiation distance and two risk factors, habituation to human presence and perch height, in Anolis lineatopus, a trunk-ground anole and A. grahami, a trunk-crown anole. Sample sizes for A. lineatopus and A. grahami were 214 and 93, for microhabitat use and escape destinations, 74 and 34 for human presence and 125 and 34 for perch height. The two species occurred in similar microhabitats and exhibited similar escape tactics, but exhibited key differences expected for their ecomorphs. Both species were sighted frequently on the ground and on trees, but A. lineatopus were more frequently on ground and were perched lower than A. grahami. Both species escaped from ground to trees and when on trees hid on far sides and escaped without changing climbing direction with equal frequency. The frequency of fleeing upward was greater for A. grahami than A. lineatopus. Both species exhibited habituation by having shorter flight initiation distances in areas with more frequent exposure to people. In both species flight initiation distance increased as perch height decreased because, lizards had to climb farther to be out of reach when perched lower. The

  6. Decrease of Population Divergence in Eurasian Perch (Perca fluviatilis) in Browning Waters: Role of Fatty Acids and Foraging Efficiency

    PubMed Central

    Scharnweber, Kristin; Strandberg, Ursula; Karlsson, Konrad; Eklöv, Peter

    2016-01-01

    Due to altered biogeochemical processes related to climate change, highly colored dissolved organic carbon (DOC) from terrestrial sources will lead to a water “brownification” in many freshwater systems of the Northern Hemisphere. This will create deteriorated visual conditions that have been found to affect habitat-specific morphological variations in Eurasian perch (Perca fluviatilis) in a previous study. So far, potential drivers and ultimate causes of these findings have not been identified. We conducted a field study to investigate the connection between morphological divergence and polyunsaturated fatty acid (PUFA) composition of perch from six lakes across a gradient of DOC concentration. We expected a decrease in the prevalence of PUFAs, which are important for perch growth and divergence with increasing DOC concentrations, due to the restructuring effects of DOC on aquatic food webs. In general, rate of morphological divergence in perch decreased with increasing DOC concentrations. Proportions of specific PUFAs (22:6n-3, 18:3n-3, 20:5n-3, and 20:4n-6) identified to primarily contribute to overall differences between perch caught in clear and brown-water lakes tended to be connected to overall decline of morphological divergence. However, no overall significant relationship was found, indicating no severe limitation of essential fatty acids for perch inhabiting brown water lakes. We further broaden our approach by conducting a laboratory experiment on foraging efficiency of perch. Therefore, we induced pelagic and littoral phenotypes by differences in habitat-structure and feeding mode and recorded attack rate in a feeding experiment. Generally, fish were less efficient in foraging on littoral prey (Ephemeroptera) when visual conditions were degraded by brown water color. We concluded that browning water may have a strong effect on the forager’s ability to find particular food resources, resulting in the reduced development of evolutionary traits

  7. The Effect of Cooled Perches on Immunological Parameters of Caged White Leghorn Hens during the Hot Summer Months

    PubMed Central

    Strong, Rebecca A.; Hester, Patricia Y.; Eicher, Susan D.; Hu, Jiaying; Cheng, Heng-Wei

    2015-01-01

    The objective of this study was to determine if thermally cooled perches improve hen immunity during hot summer. White Leghorn pullets at 16 week of age were randomly assigned to 18 cages of 3 banks at 9 hens per cage. Each bank was assigned to 1 of the 3 treatments up to 32 week of age: 1) thermally cooled perches, 2) perches with ambient air, and 3) cages without perches. Hens were exposed to natural ambient temperatures from June through September 2013 in Indiana with a 4 h acute heat episode at 27.6 week of age. The packed cell volume, heterophil to lymphocyte (H/L) ratio, plasma concentrations of total IgG, and cytokines of interleukin-1β and interleukin-6, plus lipopolysaccharide-induced tumor necrosis factor-α factor were measured at both 27.6 and 32 week of age. The mRNA expressions of these cytokines, toll-like receptor-4, and inducible nitric oxide synthase were also examined in the spleen of 32 week-old hens. Except for H/L ratio, thermally cooled perches did not significantly improve currently measured immunological indicators. These results indicated that the ambient temperature of 2013 summer in Indiana (24°C, 17.1 to 33.1°C) was not high enough and the 4 h heat episode at 33.3°C (32 to 34.6°C) was insufficient in length to evoke severe heat stress in hens. However, cooled perch hens had a lower H/L ratio than both air perch hens and control hens at 27.6 week of age and it was still lower compared to control hens (P < 0.05, respectively) at 32 week of age. The lowered H/L ratio of cooled perch hens may suggest that they were able to cope with acute heat stress more effectively than control hens. Further studies are needed to evaluate the effectiveness of thermally cooled perches on hen health under higher ambient temperatures. PMID:26495988

  8. Evidence of impaired health in yellow perch (Perca flavescens) from a biological mercury hotspot in northeastern North America.

    PubMed

    Batchelar, Katharina L; Kidd, Karen A; Drevnick, Paul E; Munkittrick, Kelly R; Burgess, Neil M; Roberts, Aaron P; Smith, James D

    2013-03-01

    Few studies have investigated the effects of mercury (Hg) on wild fish from remote areas, even though these fish can have high total Hg concentrations. In Kejimkujik National Park and National Historic Site (KNPNHS), Nova Scotia, Canada, concentrations of total Hg in many yellow perch (Perca flavescens) currently exceed the estimated threshold level for adverse effects in fish (0.2 µg Hg g(-1) (wet wt), whole body). To determine whether Hg exposure is adversely affecting the general health of these fish, the authors collected male and female perch in the fall of 2009 and 2010 from 12 lakes within KNPNHS. The health endpoints condition, liver somatic index (LSI), and macrophage aggregates (MAs; indicators of oxidative stress and tissue damage) in the liver, kidney, and spleen were examined, and in female perch were compared between lakes and related to Hg concentrations measured in the muscle and liver tissue. No negative relationships between fish condition or LSI and Hg were found. However, within the liver, kidney, and spleen tissues of females, the relative area occupied by MAs was positively related to both muscle and liver Hg concentrations, indicating the health of these perch was adversely affected at the cellular level. These findings raise concerns for the health of these perch as well as for other wild fish populations known to have similarly elevated Hg concentrations.

  9. Hypoxia tolerance of introduced Nile perch: Implications for survival of indigenous fishes in the Lake Victoria basin

    USGS Publications Warehouse

    Schofield, P.J.; Chapman, L.J.

    2000-01-01

    The introduction of predatory Nile perch (Lates niloticus) into the Lake Victoria basin coincided with a dramatic decline in fish diversity. However, remnant populations of indigenous fishes persist in lagoons and satellite lakes separated from the main lakes by extensive areas of swamp, while other indigenous species find refuge in ecotonal areas at edges of marginal swamps in the main lakes. Low-oxygen conditions in these wetlands may physiologically stress Nile perch and therefore minimize its interaction with prey species. This study examined the low-oxygen tolerance of Nile perch collected from Lake Nabugabo, Uganda, by documenting behavioural and physiological strategies that relate to oxygen uptake. In response to hypoxia, Nile perch used aquatic surface respiration (ASR) at the air-water interface, ventilating their gills with water from the surface. However, several lines of evidence suggest that Nile perch in Lake Nabugabo are inefficient at ASR and relatively intolerant of low oxygen conditions. These include high thresholds for ASR relative to other indigenous fishes of the Lake Victoria basin, no decrease in gill ventilation rate with the onset of ASR, a faster time to loss of equilibrium in hypoxic conditions than other species from the region, and a high critical oxygen tension (24 mm Hg).

  10. Nourishment of perched sand dunes and the issue of erosion control in the Great Lakes

    NASA Astrophysics Data System (ADS)

    Marsh, William M.

    1990-09-01

    Although limited in coverage, perched sand dunes situated on high coastal bluffs are considered the most prized of Great Lakes dunes. Grand Sable Dunes on Lake Superior and Sleeping Bear Dunes on Lake Michigan are featured attractions of national lakeshores under National Park Service management. The source of sand for perched dunes is the high bluff along their lakeward edge. As onshore wind crosses the bluff, flow is accelerated upslope, resulting in greatly elevated levels of wind stress over the slope brow. On barren, sandy bluffs, wind erosion is concentrated in the brow zone, and for the Grand Sable Bluff, it averaged 1 m3/yr per linear meter along the highest sections for the period 1973 1983. This mechanism accounts for about 6,500 m3 of sand nourishment to the dunefield annually and clearly has been the predominant mechanism for the long-term development of the dunefield. However, wind erosion and dune nourishment are possible only where the bluff is denuded of plant cover by mass movements and related processes induced by wave erosion. In the Great Lakes, wave erosion and bluff retreat vary with lake levels; the nourishment of perched dunes is favored by high levels. Lake levels have been relatively high for the past 50 years, and shore erosion has become a major environmental issue leading property owners and politicians to support lake-level regulation. Trimming high water levels could reduce geomorphic activity on high bluffs and affect dune nourishment rates. Locally, nourishment also may be influenced by sediment accumulation associated with harbor protection facilities and by planting programs aimed at stabilizing dunes.

  11. Relative importance of perch and facilitative effects on nucleation in tropical woodland in Malawi

    NASA Astrophysics Data System (ADS)

    Fujita, Tomohiro

    2016-01-01

    Individual trees in open vegetation such as woodlands can act as "nuclei" for the colonization of forest tree species, which consequently lead to the formation of forest patches. This phenomenon is known as nucleation. The mechanism of nucleation is generally attributed to two factors: trees provide perches for frugivores that increase seed deposition (perch effect), and tree crowns ameliorate environmental conditions, which improves seedling establishment (facilitative effect). Few studies have attempted to distinguish the relative importance of these two factors. In this study, I separated these two effects in a woodland in northern Malawi. I chose Ficus natalensis as a potential nuclei tree because large individuals of this species are commonly located at the center of forest patches within open woodland at the study site. I monitored several environmental variables, seedling survival, seedling composition, and seed rain at three microsites: under F. natalensis, under Brachystegia floribunda (a dominant woodland species), and in open sites. Both tree species provided similar favorable conditions for the establishment of forest species compared to open sites. Thus, the survival of forest tree seedlings under F. natalensis and B. floribunda was similar, and substantially higher than seedling survival in open sites. However, communities of naturally occurring seedlings differed significantly between F. natalensis and B. floribunda. These results indicate that the facilitative effect alone cannot explain the nucleation pattern. I attribute this result to the perch effect of F. natalensis because the forest seedling species recorded under F. natalensis reportedly have small, brightly colored diaspores, which are indicative of dispersal by birds. Seed deposition of forest species under F. natalensis was significantly higher than that under B. floribunda or in open sites. My findings reinforce the idea that trees will lead to nucleation when they enhance seed

  12. Chronic environmental warming alters cardiovascular and haematological stress responses in European perch (Perca fluviatilis).

    PubMed

    Ekström, Andreas; Jutfelt, Fredrik; Fredrik Sundström, L; Adill, Anders; Aho, Teija; Sandblom, Erik

    2016-12-01

    Environmental warming and acute stress increase cardiorespiratory activity in ectothermic animals like fish. While thermal acclimation can buffer the direct thermal effects on basal cardiorespiratory function during chronic warming, little is known about how acclimation affects stress-induced cardiorespiratory responses. We compared cardiovascular and haematological responses to chasing stress in cannulated wild European perch (Perca fluviatilis) from a reference area at natural temperature (16 °C) with perch from the 'Biotest enclosure'; an experimental system chronically warmed (22 °C) by effluents from a nuclear power plant. Routine blood pressure was similar, but Biotest perch had slightly higher resting heart rate (59.9 ± 2.8 vs 51.3 ± 2.9 beats min(-1)), although the Q 10 for heart rate was 1.3, indicating pronounced thermal compensation. Chasing stress caused hypertension and a delayed tachycardia in both groups, but the maximum heart rate increase was 2.5-fold greater in Biotest fish (43.3 ± 4.3 vs 16.9 ± 2.7 beats min(-1)). Moreover, the pulse pressure response after stress was greater in reference fish, possibly due to the less pronounced tachycardia or a greater ventricular pressure generating capacity and thermally mediated differences in aortic compliance. Baseline haematological status was also similar, but after chasing stress, the haematocrit was higher in Biotest fish due to exacerbated red blood cell swelling. This study highlights that while eurythermal fishes can greatly compensate routine cardiorespiratory functions through acclimation processes, stress-induced responses may still differ markedly. This knowledge is essential when utilising cardiorespiratory variables to quantify and compare stress responses across environmental temperatures, and to forecast energetic costs and physiological constraints in ectothermic animals under global warming.

  13. Modeling of perched leachate zone formation in municipal solid waste landfills.

    PubMed

    Di Bella, Gaetano; Di Trapani, Daniele; Mannina, Giorgio; Viviani, Gaspare

    2012-03-01

    The paper presents a 1D mathematical model for the simulation of the percolation fluxes throughout a landfill for municipal solid waste (MSW). Specifically, the model was based on mass balance equations, that enable simulation of the formation of perched leachate zones in a landfill for MSW. The model considers the landfill divided in several layers evaluating the inflow to and outflow from each layer as well as the continuous moisture distribution. The infiltration flow was evaluated by means of the Darcy's law for an unsaturated porous medium, while the moisture distribution evaluation has been carried out on the basis of the theory of the vertically distributed unsaturated flow. The solution of the model has been obtained by means of the finite difference method. The model has been applied to a semi-idealized landfill located in Palermo landfill (Bellolampo). Specifically, field measurements were conducted to determine the relationship between waste density and applied vertical strain. This relationship was then used to relate vertical strain to waste porosity. The inflow rate to the system was simulated via a synthetic hyetograph whose characteristics have been identified in a previous hydrologic study. Three simulations, each with a different initial moisture content, were conducted. The model results showed a different response of the landfill in terms both of flow rates throughout the landfill and moisture profile. Indeed, the initial moisture content drastically influenced not only the formation of perched leachate zones but also their extension. The model can be a useful tool in predicting potential for the formation of perched leachate zones. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. The role of the perch effect on the nucleation process in Mediterranean semi-arid oldfields

    NASA Astrophysics Data System (ADS)

    Pausas, Juli G.; Bonet, Andreu; Maestre, Fernando T.; Climent, Anna

    2006-05-01

    Oldfield succession in Mediterranean ecosystems has been studied extensively in mesic conditions. However, this phenomenon is still poorly understood in semi-arid Mediterranean areas, where reduced plant cover, the importance of facilitation processes and the role of abiotic factors make these environments distinct. We first test whether the carob tree ( Ceratonia siliqua) generates nucleation patterns in semi-arid oldfields, and to what extent such patterns change with abandonment age. Then we test to what extent nucleation can be explained by the perch effect. And finally, we test whether the nucleated pattern around carob trees is a source of diversity in the oldfields studied. To answer these questions we located oldfields abandoned 25 and 50 years ago (20 in each case) in the Alacant Province (SE Spain, Iberian Peninsula) on the basis of aerial photographs and personal interviews with local landowners and managers. In each oldfield woody plant density and richness were sampled on two microsites: under the carob tree and in the open field. Analysis was performed on all woody plants and by separating the species in two functional groups: fleshy-fruited (with fleshy mesocarp) and non-fleshy-fruited species. The results suggest that woody vegetation colonising abandoned C. siliqua fields in SE Spain is not randomly distributed but follows a nucleation pattern with higher plant density under the trees. However, the nucleation pattern is only significant for fleshy-fruited species, suggesting that facilitative interactions alone cannot explain the nucleation pattern and that the perch effect plays an important role. The results also show that the nucleation pattern (total plant density and density of non-fleshy-fruited plants) did not increase with abandonment age, while the perch effect (density of fleshy-fruited plants) did increase significantly. Furthermore, the results also show that the nucleation pattern is not only a loci of high plant density but also a

  15. Improved COI barcoding primers for Southeast Asian perching birds (Aves: Passeriformes).

    PubMed

    Lohman, David J; Prawiradilaga, Dewi M; Meier, Rudolf

    2009-01-01

    The All Birds Barcoding Initiative aims to assemble a DNA barcode database for all bird species, but the 648-bp 'barcoding' region of cytochrome c oxidase subunit I (COI) can be difficult to amplify in Southeast Asian perching birds (Aves: Passeriformes). Using COI sequences from complete mitochondrial genomes, we designed a primer pair that more reliably amplifies and sequences the COI barcoding region of Southeast Asian passerine birds. The 655-bp region amplified with these primers overlaps the COI region amplified with other barcoding primer pairs, enabling direct comparison of sequences with previously published DNA barcodes. © 2008 The Authors. Journal compilation © 2008 Blackwell Publishing Ltd.

  16. Biological half-life of radioactive cesium in Japanese rockfish Sebastes cheni contaminated by the Fukushima Daiichi nuclear power plant accident.

    PubMed

    Matsumoto, Akira; Shigeoka, Yu; Arakawa, Hisayuki; Hirakawa, Naoto; Morioka, Yoshiaki; Mizuno, Takuji

    2015-12-01

    Since the Fukushima accident in March 2011 the concentration of radioactive cesium in Japanese rockfish (Sebastes cheni) has been decreasing slower than other fish species. The aim of this study was therefore to investigate the possibility of slow elimination rate (i.e., relatively longer Tb) as one of the reasons for the slow decrease in (137)Cs concentrations in Japanese rockfish (S. cheni). To do this, we reared twenty-three individuals of this species for a period of about 1 year, during which time we measured the (137)Cs concentrations and γ-ray spectra 14 times by using a high-efficiency NaI(Tl) scintillator. We then examined the relationship between the (137)Cs concentrations and the total length of each individual. We estimated the biological half-life (Tb, day) for each individual using the total number of (137)Cs counts in the energy region, and examined the effects of total length and (137)Cs concentration on Tb by generalized linear model (GLM). We also examined the effect of sex, total length, seawater temperature, and the (137)Cs concentration of seawater on temporal changes in the (137)Cs count reduction rate by GLM. There was no clear relationship between the corrected whole-body (137)Cs concentrations and the total length in females, however there was a significant positive correlation between these two variables in males. The difference between males and females may be attributable to variation in the degree of dilution because of variable growth of individuals, and suggests that the (137)Cs concentrations of small individuals may be greatly diluted because of faster growth. However, there was no significant difference in Tb between sexes. The mean Tb (±SD) in all individuals was 269 (±39) days; this Tb value is 2.7-5.4 times longer than past Tb values (marine fish: 50-100 days), and is thought to be one of the reasons for the slower decrease in (137)Cs concentrations in this species than other fish species on the coast of Fukushima. The GLM

  17. Impact of different colours of artificial light at night on melatonin rhythm and gene expression of gonadotropins in European perch.

    PubMed

    Brüning, Anika; Hölker, Franz; Franke, Steffen; Kleiner, Wibke; Kloas, Werner

    2016-02-01

    The distribution and intensity of artificial light at night, commonly referred to as light pollution, is consequently rising and progressively also ecological implications come to light. Low intensity light is known to suppress nocturnal melatonin production in several fish species. This study aims to examine the least suppressive light colour for melatonin excreted into the holding water and the influence of different light qualities and quantities in the night on gene expression of gonadotropins in fish. European perch (Perca fluviatilis) were exposed to light of different wavelengths during the night (blue, green, and red). Melatonin concentrations were measured from water samples every 3h during a 24h period. Gene expression of gonadotropins was measured in perch exposed to different light colours and was additionally examined for perch subjected to different intensities of white light (0 lx, 1 lx, 10 lx, 100 lx) during the night. All different light colours caused a significant drop of melatonin concentration; however, blue light was least suppressive. Gene expression of gonadotropins was not influenced by nocturnal light of different light colours, but in female perch gonadotropin expression was significantly reduced by white light already at the lowest level (1 lx). We conclude that artificial light with shorter wavelengths at night is less effective in disturbing biological rhythms of perch than longer wavelengths, coinciding with the light situation in freshwater habitats inhabited by perch. Different light colours in the night showed no significant effect on gonadotropin expression, but white light in the night can disturb reproductive traits already at very low light intensities. These findings indicate that light pollution has not only the potential to disturb the melatonin cycle but also the reproductive rhythm and may therefore have implications on whole species communities.

  18. Seasonal and Sex-Specific mRNA Levels of Key Endocrine Genes in Adult Yellow Perch (Perca flavescens) from Lake Erie

    USDA-ARS?s Scientific Manuscript database

    Yellow perch exhibit a sexual size dimorphism (SSD) where females grow faster and larger than males and estrogen preferentially stimulates growth in females. In an effort to gain more understanding of yellow perch endocrinology, real-time quantitative PCR (qPCR) was used to measure pituitary, liver...

  19. Rootless shield and perched lava pond collapses at Kīlauea Volcano, Hawai'i

    USGS Publications Warehouse

    Patrick, Matthew R.; Orr, Tim R.

    2012-01-01

    Effusion rate is a primary measurement used to judge the expected advance rate, length, and hazard potential of lava flows. At basaltic volcanoes, the rapid draining of lava stored in rootless shields and perched ponds can produce lava flows with much higher local effusion rates and advance velocities than would be expected based on the effusion rate at the vent. For several months in 2007–2008, lava stored in a series of perched ponds and rootless shields on Kīlauea Volcano, Hawai'i, was released episodically to produce fast-moving 'a'ā lava flows. Several of these lava flows approached Royal Gardens subdivision and threatened the safety of remaining residents. Using time-lapse image measurements, we show that the initial time-averaged discharge rate for one collapse-triggered lava flow was approximately eight times greater than the effusion rate at the vent. Though short-lived, the collapse-triggered 'a'ā lava flows had average advance rates approximately 45 times greater than that of the pāhoehoe flow field from which they were sourced. The high advance rates of the collapse-triggered lava flows demonstrates that recognition of lava accumulating in ponds and shields, which may be stored in a cryptic manner, is vital for accurately assessing short-term hazards at basaltic volcanoes.

  20. Approaches to the simulation of unconfined flow and perched groundwater flow in MODFLOW.

    PubMed

    Bedekar, Vivek; Niswonger, Richard G; Kipp, Kenneth; Panday, Sorab; Tonkin, Matthew

    2012-01-01

    Various approaches have been proposed to manage the nonlinearities associated with the unconfined flow equation and to simulate perched groundwater conditions using the MODFLOW family of codes. The approaches comprise a variety of numerical techniques to prevent dry cells from becoming inactive and to achieve a stable solution focused on formulations of the unconfined, partially-saturated, groundwater flow equation. Keeping dry cells active avoids a discontinuous head solution which in turn improves the effectiveness of parameter estimation software that relies on continuous derivatives. Most approaches implement an upstream weighting of intercell conductance and Newton-Raphson linearization to obtain robust convergence. In this study, several published approaches were implemented in a stepwise manner into MODFLOW for comparative analysis. First, a comparative analysis of the methods is presented using synthetic examples that create convergence issues or difficulty in handling perched conditions with the more common dry-cell simulation capabilities of MODFLOW. Next, a field-scale three-dimensional simulation is presented to examine the stability and performance of the discussed approaches in larger, practical, simulation settings.

  1. Approaches to the simulation of unconfined flow and perched groundwater flow in MODFLOW

    USGS Publications Warehouse

    Bedekar, Vivek; Niswonger, Richard G.; Kipp, Kenneth; Panday, Sorab; Tonkin, Matthew

    2012-01-01

    Various approaches have been proposed to manage the nonlinearities associated with the unconfined flow equation and to simulate perched groundwater conditions using the MODFLOW family of codes. The approaches comprise a variety of numerical techniques to prevent dry cells from becoming inactive and to achieve a stable solution focused on formulations of the unconfined, partially-saturated, groundwater flow equation. Keeping dry cells active avoids a discontinuous head solution which in turn improves the effectiveness of parameter estimation software that relies on continuous derivatives. Most approaches implement an upstream weighting of intercell conductance and Newton-Raphson linearization to obtain robust convergence. In this study, several published approaches were implemented in a stepwise manner into MODFLOW for comparative analysis. First, a comparative analysis of the methods is presented using synthetic examples that create convergence issues or difficulty in handling perched conditions with the more common dry-cell simulation capabilities of MODFLOW. Next, a field-scale three-dimensional simulation is presented to examine the stability and performance of the discussed approaches in larger, practical, simulation settings.

  2. Arboreal habitat structure affects locomotor speed and perch choice of white-footed mice (Peromyscus leucopus).

    PubMed

    Hyams, Sara E; Jayne, Bruce C; Cameron, Guy N

    2012-11-01

    Arboreal habitats pose several challenges for locomotion resulting from narrow cylindrical surfaces, steep slopes, and secondary branches that can form obstructions. We used laboratory trials to test whether different diameters, slopes, or complexity of branches affected maximum speeds and perch choice of the semi-arboreal white-footed mouse (Peromyscus leucopus). We tested locomotor performance of mice running horizontally and up and down 45° slopes for cylindrical artificial branches with five diameters ranging from 10 to 116 mm and on a subset of diameters for cylinders that were horizontal and had pegs (e.g., secondary branches) every 10 or 20 cm. Slope, diameter, and presence of pegs on top of cylinders had significant and interactive effects on locomotor performance. On horizontal cylinders the speed of mice increased with increased diameter among the three smallest diameters, but changed little with further increases in diameter, whereas for sloped surfaces the extreme diameters had lower speeds than an intermediate diameter. For a given diameter, the speeds of mice were usually faster when running horizontally rather than running uphill or downhill. The presence of pegs greatly decreased running speed compared to unobstructed surfaces, but the magnitude of this effect decreased as diameter increased. The difficulties of maintaining balance and avoiding toppling may have caused much of the decrease in speed and associated increased amounts of pausing. Only 1 of 11 choice tests detected a significant bias of mice favoring the perch that maximized locomotor performance. Copyright © 2012 Wiley Periodicals, Inc.

  3. Methylmercury content of eggs in yellow perch related to maternal exposure in four Wisconsin lakes

    USGS Publications Warehouse

    Hammerschmidt, Chad R.; Wiener, James G.; Frazier, Brdaley E.; Rada, Ronald G.

    1999-01-01

    We examined the influence of maternal mercury and selected lacustrine variables on the mercury content of eggs from yellow perch (Perca flavescens). Total mercury, methylmercury, and inorganic mercury were determined in eggs and carcasses (less eggs) from three seepage lakes with a pH range of 6.1a??7.0 and a fourth lake in which pH was experimentally increased from 5.5 to 6.8 by addition of alkaline groundwater. The concentration of total mercury in eggs was strongly correlated with that in the maternal carcass. Concentrations and burdens of mercury in eggs and carcasses were inversely correlated with lake water pH, acid-neutralizing capacity, calcium, and dissolved organic carbon. In eggs containing more than 30 ng/g dry weight (4.5 ng/g wet weight) of total mercury, methylmercury averaged 91% of total mercury and ranged from 85% to 96%. Mean burdens of total mercury in individual eggs varied greatly among lakes (range, 2.3a??63 pg), and the egg mass averaged 1.9% of the whole-body burden. We conclude that exposure of the developing yellow perch embryo to methylmercury is strongly affected by maternal bioaccumulation, which can vary substantially among and within lakes; however, the toxicological significance of the observed exposure of embryos to methylmercury is unclear.

  4. Improved Low-Order Models of Bio-inspired Pitching and Perching

    NASA Astrophysics Data System (ADS)

    Wang, Chengjie; Eldredge, Jeff D.

    2011-11-01

    To study the flying of small creatures, their simplest flapping motions, pitching and perching, are investigated by low-order inviscid point vortex models. These motions induce coherent vortex shedding at the leading edge, which has a profound influence on the generated force. Instead of fully recovering the flow field around wing, the reduced models track only small number of discrete vortices with time-varying strength to account for the unsteady aerodynamics. The idea of impulse matching is introduced to develop the new governing equation, different from the previously-developed Brown-Michael equation. For both pitching and perching motions, the results from the impulse matching model are compared with high fidelity simulations under different pitching rate and axis position, and this comparison shows a good qualitative agreement, which is better than obtained with the Brown-Michael approach. The results are also compared with previous experiments conducted in a water tunnel, and good qualitative agreement is achieved. Further, some detailed analysis of the high fidelity simulation has been performed to get intuition about the leading edge vortex, which can help us in improving the low-order model.

  5. Low-order Modeling of Bio-inspired Pitching and Perching at Low Reynolds Number

    NASA Astrophysics Data System (ADS)

    Wang, Chengjie; Eldredge, Jeff D.

    2010-11-01

    A low-order inviscid point vortex model is used to simulate the pitching and perching motion of a thin flat plate at low Reynolds number. These motions induce coherent vortex shedding at the leading edge, which has a profound influence on the generated force. The low-order method is based on the inviscid Brown-Michael point vortex model, which accounts for the unsteady aerodynamics by tracking a small number of vortices with time-varying strengths. For the pitching motion, the results from the low-order model are compared with high fidelity simulations under different pitching rate and axis position, and this comparison shows a good qualitative agreement. The perching motion is characterized by larger rotations and an unsteady translation. The low-order model results are compared with previous experiments conducted in a water tunnel, and good qualitative agreement is achieved. To investigate the mechanism of force generation, the force obtained from the model is decomposed into inertial reaction and circulatory components, and their relative contributions are inspected.

  6. A Red-Tailed Hawk perches on a stump at KSC.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Near a road at Kennedy Space Center, a red-tailed hawk perches on a weathered tree stump. The red-tailed hawk has a stocky build and broad, rounded wings. Its broad range covers Alaska and Nova Scotia south to Panama. It can frequently be seen perched in a tree at the edge of a meadow, watching for movement in the grass below. It feeds mainly on small rodents. The Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects. Kennedy Space Center shares a boundary with the Merritt Island National Wildlife Refuge, encompassing 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  7. Hydrogeochemical and isotope study of perched aquifers in the Cuvelai-Etosha Basin, Namibia.

    PubMed

    Hamutoko, Josefina T; Wanke, Heike; Koeniger, Paul; Beyer, Matthias; Gaj, Marcel

    2017-08-01

    A hydrogeochemical and stable isotope study ((2)H and (18)O) was carried out in the Cuvelai-Etosha Basin in order to characterize available groundwater and to identify possible recharge mechanisms for the perched aquifers. Data were collected during seven field campaigns between 2013 and 2015 from a total of 24 shallow and deep groundwater hand-dug wells. In the investigated groundwaters, hydrogencarbonate is the dominating anion in both well types, whereas cations vary between calcium and magnesium in deep wells, and sodium and potassium in shallow wells. Groundwater chemistry is controlled by dissolution of carbonate minerals, silicate weathering and ion exchange. Stable isotopic composition suggests that deep groundwater is recharged by high-intensity/large rainfall events, whereas the shallow wells can even be recharged by less-intense/small rainfall events. Water in deep wells reflect a mixture of water influenced by evaporation during or before infiltration and water that infiltrated through fast preferential pathways, whereas shallow wells are strongly influenced by evaporation. The findings of this research contribute to improve the understanding of hydrogeochemistry, recharge paths and temporal variations of perched aquifers.

  8. A Red-Tailed Hawk perches on a stump at KSC.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Near a road at Kennedy Space Center, a red-tailed hawk perches on a weathered tree stump. The red-tailed hawk has a stocky build and broad, rounded wings. Its broad range covers Alaska and Nova Scotia south to Panama. It can frequently be seen perched in a tree at the edge of a meadow, watching for movement in the grass below. It feeds mainly on small rodents. The Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects. Kennedy Space Center shares a boundary with the Merritt Island National Wildlife Refuge, encompassing 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  9. Changes in HTO and OBT activity concentrations in the Perch Lake aquatic ecosystem.

    PubMed

    Kim, S B; Farrow, F; Bredlaw, M; Stuart, M

    2016-12-01

    Perch Lake, a small shallow shield lake located on the Chalk River Laboratories (CRL) site, contains elevated levels of tritium due to inputs from a nearby nuclear waste management area. The releases have been going on for many years but tritium levels in Perch Lake have been gradually decreasing since about year 2000. Lake water, sediments, aquatic plants, clams and fish were collected during the summer and fall of 2003 and 2013 at three locations in the lake. HTO activity concentrations were measured in all samples and OBT activity concentrations were measured in sediments, plants, clams and fish. In 2003, 2013, HTO activity concentrations in lake water were roughly uniform in time and space, except close to the shoreline where concentrations were fluctuating according to stream water and groundwater tritium levels in streams entering the lake. HTO activity concentrations of biota were similar to concentrations in lake water at the site where they were collected. OBT activity concentrations in biota were not always correlating with the lake water HTO levels. OBT to HTO ratios were found to be less than 1 for aquatic plants, around 1 for clams and fish and above 1 for birds reared on the shore of the lake.

  10. Mechanical analysis of avian feet: multiarticular muscles in grasping and perching

    PubMed Central

    Backus, Spencer B.; Sustaita, Diego; Odhner, Lael U.; Dollar, Aaron M.

    2015-01-01

    The grasping capability of birds' feet is a hallmark of their evolution, but the mechanics of avian foot function are not well understood. Two evolutionary trends that contribute to the mechanical complexity of the avian foot are the variation in the relative lengths of the phalanges and the subdivision and variation of the digital flexor musculature observed among taxa. We modelled the grasping behaviour of a simplified bird foot in response to the downward and upward forces imparted by carrying and perching tasks, respectively. Specifically, we compared the performance of various foot geometries performing these tasks when actuated by distally inserted flexors only, versus by both distally inserted and proximally inserted flexors. Our analysis demonstrates that most species possess relative phalanx lengths that are conducive to grasps actuated only by a single distally inserted tendon per digit. Furthermore, proximally inserted flexors are often required during perching, but the distally inserted flexors are sufficient when grasping and carrying objects. These results are reflected in differences in the relative development of proximally and distally inserted digital flexor musculature among ‘perching’ and ‘grasping’ taxa. Thus, our results shed light on the relative roles of variation in phalanx length and digit flexor muscle distribution in an integrative, mechanical context. PMID:26064598

  11. Methylmercury content of eggs in yellow perch related to maternal exposure in four Wisconsin lakes

    SciTech Connect

    Hammerschmidt, C.R.; Frazier, B.E.; Rada, R.G.; Wiener, J.G.

    1999-04-01

    The authors examined the influence of maternal mercury and selected lacustrine variables on the mercury content of eggs from yellow perch (Perca flavescens). Total mercury, methylmercury, and inorganic mercury were determined in eggs and carcasses (less eggs) from three seepage lakes with a pH range of 6.1--7.0 and a fourth lake in which pH was experimentally increased from 5.5 to 6.8 by addition of alkaline groundwater. The concentration of total mercury in eggs was strongly correlated with that in the material carcass. Concentrations and burdens of mercury in eggs and carcasses were inversely correlated with lake water pH, acid-neutralizing capacity, calcium, and dissolved organic carbon. In eggs containing more than 30 ng/g dry weight of total mercury, methylmercury averaged 91% of total mercury and ranged from 85% to 96%. Mean burdens of total mercury in individual eggs varied greatly among lakes and the egg mass averaged 1.9% of the whole-body burden. The authors conclude that exposure of the developing yellow perch embryo to methylmercury is strongly affected by maternal bioaccumulation, which can vary substantially among and within lakes; however, the toxicological significance of the observed exposure of embryos to methylmercury is unclear.

  12. Perching but not foraging networks predict the spread of novel foraging skills in starlings.

    PubMed

    Boogert, Neeltje J; Nightingale, Glenna F; Hoppitt, William; Laland, Kevin N

    2014-11-01

    The directed social learning hypothesis suggests that information does not spread evenly through animal groups, but rather individual characteristics and patterns of physical proximity guide the social transmission of information along specific pathways. Network-based diffusion analysis (NBDA) allows researchers to test whether information spreads following a social network. However, the explanatory power of different social networks has rarely been compared, and current models do not easily accommodate random effects (e.g. allowing for individuals within groups to correlate in their asocial solving rates). We tested whether the spread of two novel foraging skills through captive starling groups was affected by individual- and group-level random and fixed effects (i.e. sex, age, body condition, dominance rank and demonstrator status) and perching or foraging networks. We extended NBDA to include random effects and conducted model discrimination in a Bayesian context. We found that social learning increased the rate at which birds acquired the novel foraging task solutions by 6.67 times, and acquiring one of the two novel foraging task solutions facilitated the asocial acquisition of the other. Surprisingly, the spread of task solutions followed the perching rather than the foraging social network. Upon acquiring a task solution, foraging performance was facilitated by the presence of group mates. Our results highlight the importance of considering more than one social network when predicting the spread of information through animal groups. This article is part of a Special Issue entitled: Cognition in the wild.

  13. Thirty-Year-Old Paradigm about Unpalatable Perch Egg Strands Disclaimed by the Freshwater Top-Predator, the European Catfish (Silurus glanis)

    PubMed Central

    Kočvara, Luboš; Sajdlová, Zuzana; Hoang The, Son Chung; Šmejkal, Marek; Peterka, Jiří

    2017-01-01

    So far, perch egg strands have been considered unpalatable biological material. However, we repeatedly found egg strands of European perch (Perca fluviatilis) in the diet of European catfish (Silurus glanis) caught by longlines in Milada and Most Lakes, Czech Republic. The finding proves that perch egg strands compose a standard food source for this large freshwater predatory fish. It extends the present knowledge on catfish foraging plasticity, showing it as an even more opportunistic feeder. Utilization of perch egg strands broadens the catfish diet niche width and represents an advantage against other fish predators. Comparison of datasets from extensive gillnet and SCUBA diver sampling campaigns gave the evidence that at least in localities where food sources are limited, multilevel predation by catfish may have an important impact on the perch population. PMID:28060862

  14. Development of sperm vitrification protocols for freshwater fish (Eurasian perch, Perca fluviatilis) and marine fish (European eel, Anguilla anguilla).

    PubMed

    Kása, Eszter; Bernáth, Gergely; Kollár, Tímea; Żarski, Daniel; Lujić, Jelena; Marinović, Zoran; Bokor, Zoltán; Hegyi, Árpád; Urbányi, Béla; Vílchez, M Carmen; Morini, Marina; Peñaranda, David S; Pérez, Luz; Asturiano, Juan F; Horváth, Ákos

    2017-05-01

    Vitrification was successfully applied to the sperm of two fish species, the freshwater Eurasian perch (Perca fluviatilis) and marine European eel (Anguilla anguilla). Sperm was collected, diluted in species-specific non-activating media and cryoprotectants and vitrified by plunging directly into liquid nitrogen without pre-cooling in its vapor. Progressive motility of fresh and vitrified-thawed sperm was evaluated with computer-assisted sperm analysis (CASA). Additional sperm quality parameters such as sperm head morphometry parameters (in case of European eel) and fertilizing capacity (in case of Eurasian perch) were carried out to test the effectiveness of vitrification. The vitrification method for Eurasian perch sperm resulting the highest post-thaw motility (14±1.6%) was as follows: 1:5 dilution ratio, Tanaka extender, 30% cryoprotectant (15% methanol+15% propylene-glycol), cooling device: Cryotop, 2μl droplets, and for European eel sperm: dilution ratio 1:1, with 40% cryoprotectant (20% MeOH and 20% PG), and 10% FBS, cooling device: Cryotop, with 2μl of sperm suspension. Viable embryos were produced by fertilization with vitrified Eurasian perch sperm (neurulation: 2.54±1.67%). According to the ASMA analysis, no significant decrease in head area and perimeter of vitrified European eel spermatozoa were found when compared to fresh spermatozoa.

  15. Identification of gender in yellow perch by external morphology: validation in four geographic strains and effects of estradiol

    USDA-ARS?s Scientific Manuscript database

    External morphological criteria that enable the rapid determination of gender have been developed for yellow perch (Perca flavescens). Criteria are based upon 1) shape of the urogenital papilla (UGP), 2) relative size of the UGP to the anal (AN) opening, and 3) coloration of the UGP. In females, t...

  16. Comparative population genetic structure and diversity of Yellow Perch and Walleye: Broad- and fine-scale patterns across North America

    USDA-ARS?s Scientific Manuscript database

    The yellow perch Perca flavescens and the walleye Sander vitreus are native North American percid fishes, which have considerable fishery and ecological importance across their wide geographic ranges. Over the past century, they were stocked into new habitats, often with relative disregard for conse...

  17. The effect of cooled perches on immunological parameters of caged White Leghorn hens during the hot summer months

    USDA-ARS?s Scientific Manuscript database

    The objective of this study was to determine if thermally cooled perches improved hen immunity during the hot summer months. White Leghorn pullets at 16 weeks of age were randomly assigned to 18 cages of 3 banks at 9 hens per cage. Each bank was assigned to 1 of the 3 treatments up to 32 weeks of ag...

  18. Live transport of Yellow Perch and Nile Tilapia in AQUI-S 20E (10% Eugenol) at high loading densities

    USGS Publications Warehouse

    Cupp, Aaron R.; Schreier, Theresa M.; Schleis, Sue M.

    2017-01-01

    Fish transport costs are a substantial portion of the operational expenses for aquaculture facilities in the USA. Safely transporting higher loading densities of fish would benefit haulers by increasing efficiency and reducing costs, but research evaluating transport for individual species is generally lacking. In this study, Yellow Perch Perca flavescens and Nile Tilapia Oreochromis niloticus were transported for 6 h immersed in water containing AQUI-S 20E (10% eugenol) at fish loading densities of 240 g/L (2 lb/gal) for perch and 480 g/L (4 lb/gal) for tilapia. Survival was quantified for fish transported in AQUI-S 20E concentrations of (1) control or 0 mg/L of water, (2) 100 mg/L, or (3) 200 mg/L. Yellow Perch had 98–100% survival, and Nile Tilapia had 100% survival up to through 14 d after transport across all AQUI-S 20E levels, including the control. Eugenol concentrations decreased rapidly in transport tank water, and fish showed no signs of sedation by the end of transport. We conclude that live transport of Yellow Perch and Nile Tilapia at higher loading densities resulted in high survival regardless of the AQUI-S 20E concentrations we tested.

  19. Genetic diversity and associated pathology of rhabdovirus infections in farmed and wild perch Perca fluviatilis in Ireland.

    PubMed

    Ruane, N M; Rodger, H D; McCarthy, L J; Swords, D; Dodge, M; Kerr, R C; Henshilwood, K; Stone, D M

    2014-12-02

    Rhabdovirus infections are an emerging problem for both wild and farmed freshwater fish in Northern Europe. In October 2005, a clinical outbreak with an approximate mortality rate of 40% occurred in a single batch of juvenile perch on a farm in the Republic of Ireland. Clinical signs developed slowly and were consistent with a perch rhabdovirus infection: signs included haemorrhages at the base of the fins and apparent impairment of the central nervous system (manifested as loss of equilibrium and erratic swimming behaviour). Studies suggest that the infected fish originated from a hatchery within the country which relied on wild fish broodstock to supplement the production of perch juveniles. A related rhabdovirus was subsequently isolated from this hatchery. Virus isolation studies have shown that rhabdoviruses were often isolated from wild fish in the vicinity of the hatchery between 1993 and 2005. All isolates were analysed using a generic primer set specific for the L gene of fish vesiculotype viruses. Phylogenetic analysis revealed that all isolates recovered from perch clustered together with the European lake trout rhabdovirus (903/87) of the genus Perhabdovirus. In addition to this, anguillid rhabdovirus was isolated from eel, and the partial L-gene sequence of a previously reported isolate from tench clustered with the pike fry rhabdoviruses, in the genus Sprivivirus.

  20. Complete Genome Sequence of a Fish Nervous Necrosis Virus Isolated from Sea Perch (Lateolabrax japonicus) in China

    PubMed Central

    Jia, Peng

    2015-01-01

    We sequenced and analyzed the complete genome of a fish nervous necrosis virus isolated from diseased sea perch (Lateolabrax japonicus) in Guangdong Province, China. The virus genome contains RNA1 (3,103 bp) and RNA2 (1,433 bp). Phylogenetic analysis shows that the virus belongs to the redspotted grouper nervous necrosis virus genotype of betanodavirus. PMID:26044411

  1. Host-parasite relationships as determinants of heavy metal concentrations in perch (Perca fluviatilis) and its intestinal parasite infection.

    PubMed

    Brázová, Tímea; Hanzelová, Vladimíra; Miklisová, Dana; Šalamún, Peter; Vidal-Martínez, Víctor M

    2015-12-01

    The concentrations of As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn and their bioconcentration factors (BCFs) were determined in two intestinal parasites, an acanthocephalan, Acanthocephalus lucii, a tapeworm, Proteocephalus percae, present in the same host, the European perch (Perca fluviatilis, L.), in the heavily polluted Ružín reservoir in eastern Slovakia. The bioaccumulation of heavy metals in the fish organs and parasites was studied for acanthocephalan and tapeworm monoinfections or mixed infections by the two parasites and for the size of their parasitic infrapopulations. Bioconcentration factors (c[parasite]/c[muscle tissue]) showed that the concentrations of As, Ni, Pb and Zn were higher in mixed infections than in monoinfections. Negative correlations between heavy metal concentrations in perch organs and the parasites were found. For example, higher concentrations of Ni and Zn in both parasite species corresponded with lower metal concentrations in perch and hard roe. Likewise, significant negative relationships between metal concentrations in fish organs and number of parasites were noticed with lower levels of Pb in fish harbouring higher numbers of tapeworms. Similarly, in both parasite species the concentrations of some essential elements (Cr, Mn) were lower at high infection intensities compared to low intensities. Our study revealed that the differential concentration of heavy metals in perch organs was affected by the type of infection (mono- or mixed-infection), and needs to be considered in field ecotoxicological and parasitological studies as a potentially important factor influencing the pollutant concentrations in fish.

  2. Trap perches to assess the activity of pyrethrins against the poultry red mite Dermanyssus gallinae in cage birds.

    PubMed

    McGarry, J W; Trees, A J

    1991-09-01

    Trap perches were utilised to quantify mite recoveries during efficacy tests of pyrethrin formulations against experimental infestations of Dermanyssus gallinae (De Geer, 1778) in budgerigars and pigeons, and to monitor mite recoveries from untreated canaries. Pyrethrins applied topically before infestation significantly reduced the mean numbers of poultry red mites found in both budgerigar and pigeon trap perches, over those in untreated controls (P = less than 0.01). In untreated control budgerigars and pigeons, and in untreated canaries, the percentage recoveries after 48 h were 12.6 +/- 1.6, 4.1 +/- 1.9, and 32.6 +/- 1.6%, respectively (geometric mean +/- SD), and the blood engorgements rates were 71.5 +/- 1.7, 11.9 +/- 5.1, and 90.1 +/- 1.0% respectively. The recovery in trap perches of mites from canaries declined exponentially; 85% of the cumulative total recovered was collected 24 h after infestation, but small numbers were recovered daily up to 96 h (limit of observation). The use of the trap perches is discussed as a way of assessing the efficacy of acaricides, and as a laboratory tool in studies on mite aggregation behaviour or immune responses to mite infestation.

  3. Composition and Use of Common Carp Meal as a Marine Fish Meal Replacement in Yellow Perch Diets

    USDA-ARS?s Scientific Manuscript database

    We evaluated the use of fish meal derived from a locally abundant, non-native fish species – common carp Cyprinus carpio – with the objective of offsetting the cost of marine fish meal (MFM, ~$1,200/ton) in yellow perch Perca flavescens feed. Biochemical analyses of meals showed that crude protein a...

  4. Use of Diets Containing Graded Levels of Distillers Dried Grains with Solubles and Soybean Meal by Yellow Perch (Perca flavescens)

    USDA-ARS?s Scientific Manuscript database

    A feeding trial was performed to investigate inclusion levels of distillers dried grains with solubles (DDGS) and soybean meal (SM) used in the diets of juvenile yellow perch (Perca flavescens). Six isocaloric (3.22 ± 0.02 kcal/g SE), isonitrogenous (30.1 ± 0.2% SE) experimental diets were formulate...

  5. Genetic Variation of 17 Wild Yellow Perch Populations from the Midwest and East Coast Analyzed Via Microsatellites

    USDA-ARS?s Scientific Manuscript database

    We used microsatellite loci, including seven newly developed by us, to analyze the population genetic structure of wild yellow perch Perca flavescens from 17 sampling areas in the Upper Midwest and East Coast of the United States. Our results revealed greater genetic differentiation and finer-scale ...

  6. Influence of mineral supplementation on growth in yellow perch Perca flavescens fed a soy-based diet

    USDA-ARS?s Scientific Manuscript database

    Little is known of the nutritional requirements for the growth of yellow perch in intensive aquaculture. Consequently, commercial feed formulations are based on nutritional requirements for rainbow trout, containing large quantities of fish meal and oil which are not optimal for other species. Plant...

  7. Evolutionary change driven by metal exposure as revealed by coding SNP genome scan in wild yellow perch (Perca flavescens).

    PubMed

    Bélanger-Deschênes, Sébastien; Couture, Patrice; Campbell, Peter G C; Bernatchez, Louis

    2013-07-01

    Pollution can drive rapid evolutionary change in wild populations. This study targets functional polymorphisms of chronically metal-contaminated wild yellow perch (Perca flavescens). A de novo transcriptome scan contrasted subsets of individuals from clean (n = 16) and contaminated (n = 16) lakes to identify 87 candidate annotated coding SNPs. Candidate genotypes and liver [metal] were obtained in 10 populations (n = 1,052) and a genome scan distinguished outliers: one nuclear (cyclin G1 gene) and two mitochondrial (cytochrome b and NADH dehydrogenase subunit 2 genes) also displaying allelic correlation to mean population [cadmium]. Whole mtDNA and 17 kb surrounding cyclin G1 were characterised through 454 sequencing thus revealing two non-synonymous substitutions involving dissimilar amino acids. Based on associated functions and inter-population differentiation, contaminated perch may have been selected for fast life cycle completion (p53 pathway) and memorization impairment mitigation (long-term potentiation pathway). In accordance with predicted evolutionary trajectory for stressed and energy deprived organisms, adapted perch would not compensate for repair mechanism inhibition, instead reallocating energy towards growth and favouring inexpensive impairment mitigation adaptations over costly detoxification. Overall, 85 years of selection could have driven rapid, potentially adaptive evolution by selecting alleles increasing perch fitness in polluted environments.

  8. Do water level fluctuations influence production of walleye and yellow perch young-of-the-year in large northern lakes?

    USGS Publications Warehouse

    Larson, James H.; Staples, David F.; Maki, Ryan P.; Vallazza, Jon M.; Knights, Brent C.; Peterson, Kevin E.

    2016-01-01

    Many ecological processes depend on the regular rise and fall of water levels (WLs), and artificial manipulations to WL regimes can impair important ecosystem services. Previous research has suggested that differences in WL between late summer and early spring may alter the suitability of shoals used by Walleyes Sander vitreus for spawning. Other species, such as the Yellow Perch Perca flavescens, are unlikely to be affected in the same way by WL fluctuations because their spawning requirements are quite different. We used 11–23 years of data from six northern Minnesota lakes to assess the effects of WL fluctuations on the abundances of young-of-the-year (age-0) Walleyes and Yellow Perch. In two lakes (Rainy Lake and Lake Kabetogama), a change in WL management occurred in 2000, after which these lakes saw increased age-0 Walleye abundance, while the other study lakes experienced decreases or no change. Rainy Lake and Lake Kabetogama also had increases in age-0 Yellow Perch, but another study lake did also. We used partial least-squares regression to assess whether WL metrics were associated with variation in age-0 Walleye and Yellow Perch abundances, but WL metrics were seldom associated with age-0 abundance for either species. Our analysis suggested a potential influence of WL regulation on age-0 Walleye abundance, but we found no evidence that early spring access to spawning shoals was the mechanism by which this occurred.

  9. The Effects of Extrusion Processing of Distillers Dried Grains with Solubles (DDGS)-Based Yellow Perch (Perca flavescens) Feeds

    USDA-ARS?s Scientific Manuscript database

    This study was conducted to investigate the production of balanced diets for juvenile yellow perch (Perca flavescens) feeds. Six isocaloric (3.20 kcal/g), isonitrogenous (31.5% db) ingredient blends were formulated with 0, 10, 20, 30, 40 and 50% distillers dried grains with solubles (DDGS) at a feed...

  10. Effect of gear selectivity on recommended allowable harvest with application to the Lake Erie yellow perch fishery

    USGS Publications Warehouse

    Madenjian, Charles P.; Ryan, Philip A.

    1995-01-01

    Because the 57-mm-mesh gill net is the predominant gear in the Lake Eric fishery for yellow perch Perca flavescens, gear selectivity is an important factor operating in that fishery. The selectivity curve for age-groups 2–6 is roughly symmetrical with peak vulnerability at age 4; younger and older perch are substantially less susceptible to the gear. The Beverton-Holt yield-per-recruit and Ricker equilibrium yield models were applied to the west-central Lake Erie yellow perch fishery to examine the effect of gear selectivity on yield-per-recruit analysis. All fish older than a specified recruitment age are assumed to he equally vulnerable in the Beverton-Holt yield-per-recruit analysis, but the Ricker equilibrium yield model can explicitly accommodate gear selectivity. Optimal fishing rate was estimated with both models, and then recommended allowable harvests were generated based on yellow perch population size estimates. Inclusion of gear selectivity in the yield-per-recruit analysis resulted in a 12% decrease in recommended allowable harvest. When skewed gear selectivity curves were investigated, gear selectivity had a still more pronounced effect on recommended allowable harvest.

  11. Sensory and textural attributes and fatty acid profiles of fillets of extensively and intensively farmed Eurasian perch (Percafluviatilis L.).

    PubMed

    Stejskal, V; Vejsada, P; Cepak, M; Spička, J; Vacha, F; Kouril, J; Policar, T

    2011-12-01

    Sensory attributes, texture and fatty acid profiles of fillets of Eurasian perch (Percafluviatilis L.) reared under two conditions were compared. Perch were reared either in an extensive pond-based (EC) system in polyculture with carp, or intensively cultured (IC) in a recirculation system. Attributes of raw and cooked fillets of marketable perch (120-150g) were compared. No significant differences were found between groups for odour, flavour, aftertaste, or consistency in subjective evaluation of cooked fillets. The texture profile analysis (TPA) showed raw fillets from the EC group to exhibit higher values of hardness, springiness, cohesiveness, and gumminess than the IC group. Fish from the IC group had a lower content of saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA) and a higher content of monounsaturated fatty acids (MUFA) in comparison to EC perch. The proportion of iso- and anteiso-SFAs was 2.6% in the EC group and 0.75% in the IC group. The content of n-3 PUFA was lower in IC than in EC, while the content of n-6 PUFA was higher in IC than in EC. The ratio of n-3:n-6 PUFA was 1.42 for the IC group and 2.85 for the EC group.

  12. Parasite identification, succession and infection pathways in perch fry (Perca fluviatilis): new insights through a combined morphological and genetic approach.

    PubMed

    Behrmann-Godel, Jasminca

    2013-04-01

    Identification of parasite species is particularly challenging in larval and juvenile hosts, and this hampers the understanding of parasite acquisition in early life. The work described here employs a new combination of methods to identify parasite species and study parasite succession in fry of perch (Perca fluviatilis) from Lake Constance, Germany. Classical morphological diagnostics are combined with sequence comparisons between parasite life-stages collected from various hosts within the same ecosystem. In perch fry at different stages of development, 13 different parasite species were found. Incomplete morphological identifications of cestodes of the order Proteocephalidea, and trematodes of the family Diplostomatidae were complemented with sequences of mitochondrial DNA (cytochrome oxidase 1) and/or nuclear (28 s rDNA) genes. Sequences were compared to published data and used to link the parasites in perch to stages from molluscs, arthropods and more easily identifiable developmental stages from other fishes collected in Lake Constance, which both aided parasite identification and clarified transmission pathways. There were distinct changes in parasite community composition and abundance associated with perch fry age and habitat shifts. Some parasites became more abundant in older fish, whereas the composition of parasite communities was more strongly affected by the ontogenetic shifts from the pelagic to the littoral zone.

  13. Twin screw extrusion processing of distillers dried grains with solubles (DDGS)-based Yellow Perch (Perca flavescens) feeds

    USDA-ARS?s Scientific Manuscript database

    Increases in global aquaculture production, compounded with limited availabilities of fish meal for fish feed, has created the need for alternative protein sources. Twin-screw extrusion studies were performed to investigate the production of nutritionally-balanced feeds for juvenile yellow perch (Pe...

  14. Buzzcut or Fossil? Exploring the Origin of Perched Low-Relief Landscapes in the Tropics

    NASA Astrophysics Data System (ADS)

    Cunningham, M.; Stark, C. P.; Kaplan, M. R.; Schaefer, J. M.

    2014-12-01

    Throughout the tropics, high mountain regions have a "buzzcut" appearance, with low-relief spines perched high (>2500m) above deeply incised ridge-and-valley topography. Many of these mountain ranges intersect the local LGM ELA, but few studies have speculated on the role glacial erosion may have played in shaping their perched, low-relief landforms. Instead, multiple studies have invoked an abrupt increase tectonic uplift that switched the orogen from a low-relief, low erosion rate regime to a high-relief, high erosion rate mode. In this model context, perched landscapes are fossil remnants of the low-erosion rate regime, and the presence of glacial/paraglacial landforms is coincidental. However, an alternative interpretation is possible: rather than a tectonically-forced switch in erosion rate regime, low-relief spines were cut by alpine glacial erosion. To assess the influence of glacial/paraglacial processes on the formation of low-relief topography in a tropical mountain range, we conducted fieldwork at Mount Chirripó (3819m), Costa Rica. At Mount Chirripó, the estimated LGM ELA is ~3500m. River profile analysis shows a conspicuous cluster of knickpoints at ~2500m, which has been used to infer a rapid increase in regional tectonic uplift between 1-2 Ma that produced high-relief landscapes fringing ancient, low-relief landscapes. As an alternative, we hypothesize that glacial/postglacial processes acting throughout the Pleistocene played a dominant role in the formation and preservation of Mount Chirripó's low-relief spine. At Mount Chirripó, we identified glacial erosion features between 3400-3800m, including moraines, striated bedrock, glacial till, glaciofluvial outwash and post-glacial landslides. Additionally, we observed a low-sloping valley floored by angular debris at ~3100m that we interpret to be of glacial origin. We collected samples for surface exposure age dating from erratics, striated bedrock, and landslide debris boulders. Mapping of

  15. Perched water during steady infiltration in a gradually layered soil: some theoretical results

    NASA Astrophysics Data System (ADS)

    Barontini, Stefano; Ranzi, Roberto

    2010-05-01

    Due to the genetic layering, the hydraulic conductivity at saturation Ks is usually expected to decrease across the upper soil layers. Its effect on the soil hydrological properties is related to a number of landslide triggering mechanisms. Key information in order to evaluate the soil stability are the threshold of the infiltration rate for a saturated layer or a perched water to onset, its depth, the maximum pressure head and the water content profile above the saturated soil. Anyway if Ks is gradually decreasing, as often observed in the uppermost soil layers or in mountain not-mature soils, the position of a perched water can be a priori not known, nor could be the position of the maximum pressure head. These topics were theoretically discussed considering an undeformable soil layer of finite depth, characterised by gradually and monotonically decreasing Ks, in which a steady one-dimensional infiltration takes place at a rate i. At the bottom of the domain a saturation condition was assumed. Two classes of soil constitutive laws were considered in order to represent the unsaturated soil behaviour. They are respectively characterised by a finite and by an infinite slope of the hydraulic conductivity K(φ) (where φ is the matric potential) as approaching the soil saturation. The theoretical results were particularized for a soil with exponentially decreasing Ks and the profiles of the hydrological properties were determined by analytical solutions of the Darcy's law. The analyses suggested the definition of a threshold for the infiltration rate i for the perched water to onset, and allowed to determine the characteristics of the saturated layer, its pressure head profile and the position of the maximum pressure head as a function of the infiltration rate. Moreover, the hydrological properties profiles obtained for the overlaying unsaturated soil stressed the high sensitivity of the solution to the K(φ) model near saturation. The stronger is the reduction of K

  16. Tropical fish in a warming world: thermal tolerance of Nile perch Lates niloticus (L.) in Lake Nabugabo, Uganda

    PubMed Central

    Chrétien, Emmanuelle; Chapman, Lauren J.

    2016-01-01

    Key to predicting the response of fishes to climate change is quantifying how close fish are to their critical thermal limits in nature and their ability to adjust their thermal sensitivity to maintain performance. Here, we evaluated the effects of body size and habitat on aerobic scope (AS) and thermal tolerance of Nile perch Lates niloticus (L.), a fish of great economic and food security importance in East Africa, using respirometry and critical thermal maximum (CTmax) trials. Juvenile Nile perch from distinct habitats (high or low dissolved oxygen concentrations) of Lake Nabugabo, Uganda were exposed for 4.6 ± 0.55 days to a temperature treatment (25.5, 27.5, 29.5 or 31.5°C) prior to experimentation, with the lowest temperature corresponding to the mean annual daytime temperature in Lake Nabugabo and the highest temperature being 3°C higher than the maximal monthly average. As expected, metabolic rates increased with body mass. Although resting metabolic rate increased with temperature, maximal metabolic rate showed no change. Likewise, AS did not vary across treatments. The CTmax increased with acclimation temperature. There was no effect of habitat on maximal metabolic rate, AS or CTmax; however, there was a trend towards a lower resting metabolic rate for Nile perch captured in the low-dissolved oxygen habitat than in well-oxygenated waters. This study shows that juvenile Nile perch maintain a large AS at temperatures near the upper limit of their natural thermal range and provides evidence that Nile perch have physiological mechanisms to deal with acute exposure to thermal stress. PMID:27990290

  17. Lipophilic antioxidants and lipid peroxidation in yellow perch subjected to various anthropogenic influences along the St. Lawrence River (QC, Canada).

    PubMed

    Landry, Catherine; Houde, Magali; Brodeur, Philippe; Spear, Philip; Boily, Monique

    2017-05-01

    In Lake Saint-Pierre (LSP), the last great widening of the St. Lawrence River (province of Québec, Canada), the yellow perch has been experiencing a significant decline since the mid-1990s. The combined effect of several stressors (deterioration of habitats appropriate for reproduction and growth, invasive species and poor water quality) seems to exert considerable influence on the yellow perch population in LSP, characterized by low recruitment. To better understand possible stressor effects at the biochemical level, LSP yellow perch were compared with other sites along a gradient of increasing human influences from upstream to downstream along the St. Lawrence River. Morphometry (size, weight, circumference and Fulton's condition factor) and biomarkers associated to the peroxidation of lipids, lipophilic antioxidants (α-tocopherol and carotenoids), along with retinoids (vitamins A1and A2) and proteins were compared between sites at the larval, juvenile and adult stages. Fulton's condition factor was similar between sites for juveniles but was significantly lower in LSP adults, suggesting a weakened physiological condition. In most contaminated sites as LSP, lipid peroxidation tended to be higher in juveniles and adults whereas the lipophilic antioxidant lycopene and proteins content were lower. Retinyl esters were significantly lower for LSP fish compared to other sites, not only in larvae but also in the livers of juveniles and adults. These results are consistent with possible altered metabolism in the retinoid system of LSP yellow perch. The overall results reflect the "pressure" gradient tested, where the yellow perch from the most affected sites located downstream had impaired physiological and biochemical conditions compared to the upstream sectors.

  18. Identifying across-system sources of variation in a generalist freshwater fish: Correlates of total and size-specific abundance of yellow perch

    USGS Publications Warehouse

    Carey, M.P.; Mather, M. E.

    2009-01-01

    Variation in fish abundance across systems presents a challenge to our understanding of fish populations because it limits our ability to predict and transfer basic ecological principles to applied problems. Yellow perch (Perca flavescens) is an ideal species for exploring environmental and biotic correlates across system because it is widely distributed and physiologically tolerant. In 16 small, adjacent systems that span a wide range of environmental and biotic conditions, yellow perch were sampled with a standard suite of gear. Water quality, morphometry, vegetation, invertebrates and fish communities were concurrently measured. Multimodel inference was used to prioritise regressors for the entire yellow perch sample and three size groups (35-80, 81-180, ???181 mm TL). Across systems, pH and fish richness were identified as the key drivers of yellow perch abundance. At very low pH (4.8) had many other species and few yellow perch. Similar patterns for pH and fish community were observed for the two largest-size classes. Negative interactions were observed between the medium- and large-sized yellow perch and between the largest and smallest yellow perch, although interspecific interactions were weaker than expected. This examination of variability for an indicator species and its component-size classes provides ecological understanding that can help frame the larger-scale sampling programs needed for the conservation of freshwater fish. ?? 2008 Blackwell Munksgaard.

  19. Uptake and elimination of 137Cs by climbing perch (Anabus testudineus).

    PubMed

    Malek, M A

    1999-12-01

    This work describes the uptake and retention/biological elimination of 137Cs by climbing perch (Anabus testudineus) under laboratory conditions. The accumulated 137Cs concentration in the whole body of the fish was measured at certain intervals up to 38 d. A significant accumulation of 137Cs was found, but a steady state accumulation of 137Cs was not achieved by the end of the experiment. The bioaccumulation factors and the distribution of the radionuclide in edible parts of the fish were determined. The effective half-life of 137Cs in the fish species was found to be approximately 147 d (average) for elderly and adult fishes and approximately 300 d for younger fishes. Accumulation of 137Cs in the edible parts of the fish was found to be approximately 77% of whole body accumulation.

  20. Parameterization of European perch Perca fluviatilis length-at-age data using stochastic Gompertz growth models.

    PubMed

    Troynikov, V S; Gorfine, H K; Ložys, L; Pūtys, Z; Jakubavičiūtė, E; Day, R W

    2011-12-01

    Three stochastic versions of the Gompertz growth model were used to parameterize total length (L(T) )-at-age data for perch Perca fluviatilis, an important target species for commercial and recreational fishers and a food species for predatory fishes and aquatic birds. Each model addresses growth heterogeneity by incorporating random parameters from a specific positive distribution: Weibull, gamma or log-normal. The modelling outputs for each version of the model provide L(T) distributions for selected ages and percentiles of L(T) at age for both males and females. The results highlight the importance of using a stochastic approach and the logistic-like growth pattern for analysing growth data for P. fluviatilis in Curonian Lagoon (Lithuania). Outputs from this modelling can be extended to a stochastic analysis of fish cohort dynamics, incorporating all length-based biological relationships, and the selectivity-related interactions between fish cohorts and fishing gear.

  1. Individuals' diet diversity influences gut microbial diversity in two freshwater fish (threespine stickleback and Eurasian perch)

    PubMed Central

    Bolnick, Daniel I; Snowberg, Lisa K; Hirsch, Philipp E; Lauber, Christian L; Knight, Rob; Caporaso, J Gregory; Svanbäck, Richard; Post, David

    2014-01-01

    Vertebrates' diets profoundly influence the composition of symbiotic gut microbial communities. Studies documenting diet-microbiota associations typically focus on univariate or categorical diet variables. However, in nature individuals often consume diverse combinations of foods. If diet components act independently, each providing distinct microbial colonists or nutrients, we expect a positive relationship between diet diversity and microbial diversity. We tested this prediction within each of two fish species (stickleback and perch), in which individuals vary in their propensity to eat littoral or pelagic invertebrates or mixtures of both prey. Unexpectedly, in most cases individuals with more generalised diets had less diverse microbiota than dietary specialists, in both natural and laboratory populations. This negative association between diet diversity and microbial diversity was small but significant, and most apparent after accounting for complex interactions between sex, size and diet. Our results suggest that multiple diet components can interact non-additively to influence gut microbial diversity. PMID:24847735

  2. PERCH in Perspective: What Can It Teach Us About Pneumonia Etiology in Children?

    PubMed

    Klugman, Keith P; Rodgers, Gail L

    2017-06-15

    The pneumonia team at the Bill & Melinda Gates Foundation congratulates the Pneumonia Etiology Research for Child Health (PERCH) study on delivering on their grant to collect high-quality data from thousands of children with World Health Organization-defined severe and very severe pneumonia and from controls in 9 diverse sites in 7 low- and middle-income countries. This supplement sets the foundation to understanding this complex study by providing an in-depth description of the study methodology, including discussion of key aspects such as antibiotic pretreatment, chest radiograph interpretation, utility of induced sputum in children, measurement of pathogen density, and use of C-reactive protein, and how these affect pneumonia etiology. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

  3. Impact of Toxic Cyanobacterial Blooms on Eurasian Perch (Perca fluviatilis): Experimental Study and In Situ Observations in a Peri-Alpine Lake

    PubMed Central

    Sotton, Benoît; Guillard, Jean; Bony, Sylvie; Devaux, Alain; Domaizon, Isabelle; Givaudan, Nicolas; Crespeau, François; Huet, Hélène; Anneville, Orlane

    2012-01-01

    Due to the importance of young-of-the-year (YOY) perch in the peri-alpine regions where they are consumed, the microcystin (MC) contamination of YOY perch was analysed both in field (Lake Bourget, France) and experimentally using force-feeding protocols with pure MCs. In-situ, schools of YOY perch present in the epilimnion of the lake were never found in direct contact with the P. rubescens blooms that were present in the metalimnion. However, MCs were detected in the muscles and liver of the fish and were thus assumed to reach YOY perch through dietary routes, particularly via the consumption of MC-containing Daphnia. Force-feeding experiment demonstrates the existence of MC detoxification/excretion processes and suggests that in situ, YOY perch could partly detoxify and excrete ingested MCs, thereby limiting the potential negative effects on perch populations under bloom conditions. However, because of chronic exposure these processes could not allow for the complete elimination of MCs. In both experimental and in situ studies, no histological change was observed in YOY perch, indicating that MC concentrations that occurred in Lake Bourget in 2009 were too low to cause histological damage prone to induce mortality. However, Deoxyribonucleic acid (DNA) damages were observed for both the high and low experimental MC doses, suggesting that similar effects could occur in situ and potentially result in perch population disturbance during cyanobacterial blooms. Our results indicate the presence of MCs in wild perch, the consumption of this species coming from Lake Bourget is not contested but more analyses are needed to quantify the risk. PMID:23272228

  4. Priority effects among young-of-the-year fish: Reduced growth of bluegill sunfish (Lepomis macrochirus) caused by yellow perch (Perca flavescens)?

    USGS Publications Warehouse

    Kaemingk, Mark A.; Jolley, Jeff C.; Willis, David W.; Chipps, Steven R.

    2012-01-01

    1. When available, Daphnia spp. are often preferred by age-0 yellow perch and bluegill sunfish because of energetic profitability. We hypothesised that predation by age-0 yellow perch could lead to a midsummer decline (MSD) of Daphnia spp. and that priority effects may favour yellow perch because they hatch before bluegill, allowing them to capitalise on Daphnia spp. prior to bluegill emergence.2. Data were collected from 2004 to 2010 in Pelican Lake, Nebraska, U.S.A. The lake experienced a prolonged MSD in all but 1 year (2005), generally occurring within the first 2 weeks of June except in 2008 and 2010 when it occurred at the end of June. MSD timing is not solely related to seasonal patterns of age-0 yellow perch consumption. Nevertheless, when Daphnia spp. biomass was low during 2004 and 2006–2010 (<4 mg wet weight L−1), predation by age-0 yellow perch seems to have suppressed Daphnia spp. biomass (i.e. <1.0 mg wet weight L−1). The exception was 2005 when age-0 yellow perch were absent.3. Growth of age-0 bluegill was significantly faster in 2005, when Daphnia spp. were available in greater densities (>4 mg wet weight L−1) compared with the other years (<0.2 mg wet weight L−1).4. We conclude that age-0 yellow perch are capable of reducing Daphnia biomass prior to the arrival of age-0 bluegill, ultimately slowing bluegill growth. Thus, priority effects favour age-0 yellow perch when competing with age-0 bluegill for Daphnia. However, these effects may be minimised if there is a shorter time between hatching of the two species, higher Daphnia spp. densities or lower age-0 yellow perch densities.

  5. Hawk Eyes II: Diurnal Raptors Differ in Head Movement Strategies When Scanning from Perches

    PubMed Central

    O'Rourke, Colleen T.; Pitlik, Todd; Hoover, Melissa; Fernández-Juricic, Esteban

    2010-01-01

    Background Relatively little is known about the degree of inter-specific variability in visual scanning strategies in species with laterally placed eyes (e.g., birds). This is relevant because many species detect prey while perching; therefore, head movement behavior may be an indicator of prey detection rate, a central parameter in foraging models. We studied head movement strategies in three diurnal raptors belonging to the Accipitridae and Falconidae families. Methodology/Principal Findings We used behavioral recording of individuals under field and captive conditions to calculate the rate of two types of head movements and the interval between consecutive head movements. Cooper's Hawks had the highest rate of regular head movements, which can facilitate tracking prey items in the visually cluttered environment they inhabit (e.g., forested habitats). On the other hand, Red-tailed Hawks showed long intervals between consecutive head movements, which is consistent with prey searching in less visually obstructed environments (e.g., open habitats) and with detecting prey movement from a distance with their central foveae. Finally, American Kestrels have the highest rates of translational head movements (vertical or frontal displacements of the head keeping the bill in the same direction), which have been associated with depth perception through motion parallax. Higher translational head movement rates may be a strategy to compensate for the reduced degree of eye movement of this species. Conclusions Cooper's Hawks, Red-tailed Hawks, and American Kestrels use both regular and translational head movements, but to different extents. We conclude that these diurnal raptors have species-specific strategies to gather visual information while perching. These strategies may optimize prey search and detection with different visual systems in habitat types with different degrees of visual obstruction. PMID:20877650

  6. Developmental Methylmercury Exposure Affects Swimming Behavior and Foraging Efficiency of Yellow Perch (Perca flavescens) Larvae.

    PubMed

    Mora-Zamorano, Francisco X; Klingler, Rebekah; Basu, Niladri; Head, Jessica; Murphy, Cheryl A; Binkowski, Frederick P; Larson, Jeremy K; Carvan, Michael J

    2017-08-31

    Methylmercury (MeHg) is a pervasive and ubiquitous environmental neurotoxicant within aquatic ecosystems, known to alter behavior in fish and other vertebrates. This study sought to assess the behavioral effects of developmental MeHg exposure on larval yellow perch (Perca flavescens)-a nonmodel fish species native to the Great Lakes. Embryos were exposed to MeHg (0, 30, 100, 300, and 1000 nM) for 20 h and then reared to 25 days post fertilization (dpf) for analyses of spontaneous swimming, visual motor response (VMR), and foraging efficiency. MeHg exposures rendered total mercury (THg) body burdens of 0.02, 0.21, 0.95, 3.14, and 14.93 μg/g (wet weight). Organisms exposed to 1000 nM exhibited high mortality; thus, they were excluded from downstream behavioral analyses. All MeHg exposures tested were associated with a reduction in spontaneous swimming at 17 and 25 dpf. Exposure to 30 and 100 nM MeHg caused altered locomotor output during the VMR assay at 21 dpf, whereas exposure to 100 nM MeHg was associated with decreased foraging efficiency at 25 dpf. For the sake of comparison, the second-lowest exposure tested here rendered a THg burden that represents the permissible level of consumable fish in the United States. Moreover, this dose is reported in roughly two-thirds of consumable fish species monitored in the United States, according to the Food and Drug Administration. Although the THg body burdens reported here were higher than expected in the environment, our study is the first to analyze the effects of MeHg exposure on fundamental survival behaviors of yellow perch larvae and advances in the exploration of the ecological relevance of behavioral end points.

  7. Connectivity in estuarine white perch populations of Chesapeake Bay: evidence from historical fisheries data

    NASA Astrophysics Data System (ADS)

    Kraus, Richard T.; Secor, David H.

    2005-07-01

    The role of complex life cycles in patterns of estuarine habitat use can be evaluated by studying stage-specific changes in abundances between principal habitats. Here, we evaluated how two primary habitats, tidal freshwater (salinity <3) and brackish water (salinity 3-15), structured juvenile white perch ( Morone americana) abundance for eight sub-estuaries of the Chesapeake Bay. In addition, abundances of juveniles in the two primary habitats were related to indices of overall sub-estuary (population) adult abundance. Smaller sub-estuaries (e.g., Patuxent, Nanticoke, Rappahannock) showed higher juvenile abundances in brackish habitats whereas larger systems (e.g., Head of Bay, Potomac, and James) exhibited higher juvenile abundances in freshwater. Within each sub-estuary, we observed strong and positive correlations between freshwater and brackish juvenile abundances. Though adult abundance indices were poor predictors of juvenile abundance in either habitat, a significant amount of variability in adult abundance was explained by juvenile abundances in prior years for most sub-estuaries. The strength of the association varied by sub-estuary and habitat and suggested that juvenile habitats may make disproportionate contributions to the adult population, dependent upon sub-estuary. There were also significant correlations in juvenile abundance between sub-estuaries, indicating inter-annual synchrony in recruitment among populations. Within sub-estuaries, river discharge did not provide a direct indication of recruitment variability, and currently there is no clear explanation for correlation in juvenile abundances between sub-estuaries. Still, a positive association between correlations in river discharge and significant correlations in juvenile abundances supported previous hypotheses that freshwater flow may be an important factor influencing juvenile abundance, but it is likely that other environmental factors are also driving synchronous fluctuations in

  8. Watershed land use is strongly linked to PCBs in white perch in Chesapeake Bay subestuaries.

    PubMed

    King, Ryan S; Beaman, Joseph R; Whigham, Dennis F; Hines, Anson H; Baker, Matthew E; Weller, Donald E

    2004-12-15

    We related total PCBs (t-PCBs) in white perch (Morone americana), an abundant estuarine resident that supports a valuable recreational and commercial fishery in the mid-Atlantic region, to the amount and spatial arrangement of developed land in watersheds that discharge into 14 subestuaries of Chesapeake Bay. We considered the intensity of development in watersheds using four developed land-use measures (% impervious surface, % total developed land, % high-intensity residential + commercial [%high-res/comm], and % commercial) to represent potential source areas of PCBs to the subestuaries. We further evaluated the importance of source proximity by calculating three inverse-distance weighted (IDW) metrics of development, an approach that weighted developed land near the shoreline more heavily than developed land farther away. Unweighted percentages of each of the four measures of developed land explained 51-69% of the variance in t-PCBs. However, IDWs markedly improved the relationships between % developed land measures and t-PCBs. Percent commercial land, weighted by its simple inverse distance, explained 99% of the variance in t-PCBs, whereas the other three measures explained as much as 93-97%. PCBs historically produced or used in commercial and residential areas are apparently persisting in the environment atthe scale of the watersheds and subestuaries examined in this study, and developed land close to the subestuary has the greatest unit effect on t-PCBs in fish. These findings provide compelling evidence for a strikingly strong linkage between watershed land use and t-PCBs in white perch, and this relationship may prove useful for identifying unsampled subestuaries with a high risk of PCB contamination.

  9. The landscape genetics of yellow perch (Perca flavescens) in a large fluvial ecosystem.

    PubMed

    Leclerc, Emilie; Mailhot, Yves; Mingelbier, Marc; Bernatchez, Louis

    2008-04-01

    Landscape genetics is being increasingly applied to elucidate the role of environmental features on the population structure of terrestrial organisms. However, the potential of this framework has been little explored in aquatic ecosystems such as large rivers. Here, we used a landscape genetics approach in order to (i) document the population structure of the yellow perch (Perca flavescens) by means of genetic variation at microsatellite markers, (ii) assess to what extent the structure was explained by landscape heterogeneity, and (iii) interpret the relevance of interactions between genetics and landscape for management and conservation. Analysis of the genetic variation among 1715 individuals from 16 localities and distributed over 310 km in the freshwater section of the Saint Lawrence River (Québec, Canada) revealed a relatively modest level of genetic structuring (F(ST) = 0.039). Application of the Monmonier's algorithm combining geographical and genetic information identified three zones of restricted gene flow defining four distinct populations. Physical barriers played a more important role on gene flow and genetic structure than waterway geographical distance. We found correlations between genetic differentiation and presence of distinct water masses in the sector of Lake Saint-Louis (r = 0.7177, P = 0.0340) and with fragmentation of spawning habitats in the sector of Lake Saint-Pierre (r = 0.8578, P = 0.0095). Our results support the treatment of four distinct biological units, which is in contrast with the current basis for yellow perch management. Finally, this study showed that landscape genetics is a powerful means to identify environmental barriers to gene flow causing genetic discontinuities in apparently highly connected aquatic landscapes.

  10. Hawk eyes II: diurnal raptors differ in head movement strategies when scanning from perches.

    PubMed

    O'Rourke, Colleen T; Pitlik, Todd; Hoover, Melissa; Fernández-Juricic, Esteban

    2010-09-22

    Relatively little is known about the degree of inter-specific variability in visual scanning strategies in species with laterally placed eyes (e.g., birds). This is relevant because many species detect prey while perching; therefore, head movement behavior may be an indicator of prey detection rate, a central parameter in foraging models. We studied head movement strategies in three diurnal raptors belonging to the Accipitridae and Falconidae families. We used behavioral recording of individuals under field and captive conditions to calculate the rate of two types of head movements and the interval between consecutive head movements. Cooper's Hawks had the highest rate of regular head movements, which can facilitate tracking prey items in the visually cluttered environment they inhabit (e.g., forested habitats). On the other hand, Red-tailed Hawks showed long intervals between consecutive head movements, which is consistent with prey searching in less visually obstructed environments (e.g., open habitats) and with detecting prey movement from a distance with their central foveae. Finally, American Kestrels have the highest rates of translational head movements (vertical or frontal displacements of the head keeping the bill in the same direction), which have been associated with depth perception through motion parallax. Higher translational head movement rates may be a strategy to compensate for the reduced degree of eye movement of this species. Cooper's Hawks, Red-tailed Hawks, and American Kestrels use both regular and translational head movements, but to different extents. We conclude that these diurnal raptors have species-specific strategies to gather visual information while perching. These strategies may optimize prey search and detection with different visual systems in habitat types with different degrees of visual obstruction.

  11. Developmental Methylmercury Exposure Affects Swimming Behavior and Foraging Efficiency of Yellow Perch (Perca flavescens) Larvae

    PubMed Central

    2017-01-01

    Methylmercury (MeHg) is a pervasive and ubiquitous environmental neurotoxicant within aquatic ecosystems, known to alter behavior in fish and other vertebrates. This study sought to assess the behavioral effects of developmental MeHg exposure on larval yellow perch (Perca flavescens)—a nonmodel fish species native to the Great Lakes. Embryos were exposed to MeHg (0, 30, 100, 300, and 1000 nM) for 20 h and then reared to 25 days post fertilization (dpf) for analyses of spontaneous swimming, visual motor response (VMR), and foraging efficiency. MeHg exposures rendered total mercury (THg) body burdens of 0.02, 0.21, 0.95, 3.14, and 14.93 μg/g (wet weight). Organisms exposed to 1000 nM exhibited high mortality; thus, they were excluded from downstream behavioral analyses. All MeHg exposures tested were associated with a reduction in spontaneous swimming at 17 and 25 dpf. Exposure to 30 and 100 nM MeHg caused altered locomotor output during the VMR assay at 21 dpf, whereas exposure to 100 nM MeHg was associated with decreased foraging efficiency at 25 dpf. For the sake of comparison, the second-lowest exposure tested here rendered a THg burden that represents the permissible level of consumable fish in the United States. Moreover, this dose is reported in roughly two-thirds of consumable fish species monitored in the United States, according to the Food and Drug Administration. Although the THg body burdens reported here were higher than expected in the environment, our study is the first to analyze the effects of MeHg exposure on fundamental survival behaviors of yellow perch larvae and advances in the exploration of the ecological relevance of behavioral end points.

  12. 78 FR 44465 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the West Yakutat...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

    ... fishery. The Acting Assistant Administrator for Fisheries, NOAA (AA), finds good cause to waive the..., 2013. The AA also finds good cause to waive the 30-day delay in the effective date of this action under...

  13. 75 FR 69601 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Central Aleutian...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ..., (AA) finds good cause to waive the requirement to provide prior notice and opportunity for public... AA also finds good cause to waive the 30-day delay in the effective date of this action under 5...

  14. 78 FR 73110 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-05

    ... information submitted voluntarily by the sender will be publicly accessible. NMFS will accept anonymous comments (enter ``N/A'' in the required fields if you wish to remain anonymous). Attachments to...

  15. 76 FR 70665 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-15

    ... business information, or otherwise sensitive or protected information. NMFS will accept anonymous comments (enter ``N/A'' in the required fields if you wish to remain anonymous). Attachments to...

  16. 78 FR 64891 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-30

    ... Acting Assistant Administrator for Fisheries, NOAA, (AA) finds good cause to waive the requirement to... became available as of October 24, 2013. The AA also finds good cause to waive the 30-day delay in...

  17. 78 FR 64892 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-30

    ... Acting Assistant Administrator for Fisheries, NOAA, (AA) finds good cause to waive the requirement to... became available as of October 24, 2013. The AA also finds good cause to waive the 30-day delay in...

  18. Old moms with new tricks: modeling the effects of age-specific spawning behaviors in Pacific Ocean perch

    EPA Science Inventory

    In commercially exploited, long-lived fish species, age structure plays an important role in determining population stability and resilience to human and environmental impacts. The often observed increase in energy allocation per offspring by older females can improve larval surv...

  19. 76 FR 39792 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch, Northern Rockfish, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-07

    ... pelagic shelf rockfish by catcher/processors participating in the limited access or opt-out fisheries that... established for catcher/processors participating in the limited access or opt-out fisheries in the Western... limit established for catcher/processors participating in the limited access or opt-out fisheries...

  20. Old moms with new tricks: modeling the effects of age-specific spawning behaviors in Pacific Ocean perch

    EPA Science Inventory

    In commercially exploited, long-lived fish species, age structure plays an important role in determining population stability and resilience to human and environmental impacts. The often observed increase in energy allocation per offspring by older females can improve larval surv...

  1. 78 FR 39631 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Western...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-02

    ... GOA is 2,040 metric tons (mt) as established by the final 2013 and 2014 harvest specifications for... opportunity for public comment pursuant to the authority set forth at 5 U.S.C. 553(b)(B) as such requirement...

  2. 76 FR 54716 - Fisheries of the Exclusive Economic Zone off Alaska; Northern Rockfish, Pacific Ocean Perch, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-02

    ... Participating in the Rockfish Entry Level Fishery AGENCY: National Marine Fisheries Service (NMFS), National... vessels participating in the rockfish entry level fishery in the Central Regulatory Area of the Gulf of... the rockfish entry level fishery in the Central Regulatory Area of the GOA. DATES: Effective 1200...

  3. High summer concentrations of mercury in big perch (Perca fluviatilis L) from the Tvärminne archipelago (SW Finland) and Nåtö (Aland Islands) Baltic sea.

    PubMed

    Voigt, H R

    2001-04-01

    During high summer seasons in 1994-1999 84 big (20-42 cm total length) female perch (Perca fluviatilis L) were sampled from the waters around Tvärminne Zoological Station on the Hanko-Hangö peninsula on the SW coast of Finland for mercury analysis. Additional sampling of 13 big female perch during the same season were carried out from the waters of Nåtö Biological Station on the Aland Islands in 1997-1998. High summer is the most important season for perch fishing and consumption not only for private families during leisure time but also for professional fishery including trade and export, processing and preparations for restaurants. Fillets of big specimen of perch, s.c. "fillet perch" or "sea perch" from outer coastal waters were chosen for the study to find out the levels of mercury concentration in these desirable fish. The mean concentration of mercury in the dorsal muscle tissue (fillet) of big female "sea perch" from the coastal waters of Tvärminne Zoological Station was calculated to 0.22 (SD 0.08), range 0.08-0.43 mg/kg, f wt and for big female perch from the waters of Nåtö Biological Station to 0.18 (SD 0.07), range 0.07-0.30 mg/kg, f wt respectively. The results show a considerably lower mercury level in big "fillet perch" caught from the outer coastal waters in both Finland (and Estonia) compared with the levels recorded of big "fillet perch" from fresh water lakes and reservoirs. Thus, the common expression "sea perch" may also be used in the form "Baltic sea perch" meaning big healthy perch with low concentrations of mercury and caught from the outer coastal waters in S and SW Finland (and W Estonia) when marketing perch for human consumption.

  4. Onset of a perched water table during infiltration in a gradually layered soil: Reanalysis of a laboratory experiment

    NASA Astrophysics Data System (ADS)

    Barontini, Stefano; Grottolo, Maria; Belluardo, Giorgio; Bacchi, Baldassare; Ranzi, Roberto

    2014-05-01

    Perched water tables in the upper soil layers play a key role in water partitioning during infiltration. They are typically thin and ephemeral, and onset in soils where a decrease of hydraulic conductivity and diffusivity is observed with depth. Aiming at better understanding their dynamics, we theoretically and numerically reanalysed a laboratory experiment, during which the onset of a perched water table was observed in a reconstructed soil with gradually decreasing conductivity at saturation with depth. The laboratory prototype was a prismatic column filled with 9 different 0.1 m--deep soil layers. The grain--size distribution curve and porosity of the layers were designed in order to reproduce an exponential decay of conductivity, on the basis of the application of a modified Kozeny--Carman relationship. During the experiment the soil was artificially wetted by means of a rainfall simulator at a rate previously determined in order to maintain a constant water content on the surface for 9 hours. Istantaneous volumetric water content profiles were measured by means of 9 multiplexed TDR probes. As a result of the experiment a water content peak was observed below the soil surface. Then it emphasised and moved downward until a perched water table formed at an intermediate height in the column, about 6 h after the beginning of the experiment. The thickness of the perched water table rapidly increased upward while the wetting front slowly travelled downward. The observed patterns supported phenomenological aspects enlightened by an analytical solution of transient infiltration in a gradually layered soil and by a numerical solution of similar cases. When the perched water table onset, the infiltration was quantitatively compatible with the presence of a perched water table within the soil column, on the basis of a steady infiltration theoretical framework. Then a reanalysis of the experiment was performed by numerically solving the Richards equation for a

  5. Reproductive, biochemical, physiological, and population responses in perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) downstream of two elemental chlorine-free pulp and paper mills.

    PubMed

    Karels, A; Markkula, E; Oikari, A

    2001-07-01

    Perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) populations in a state of late vitellogenesis were studied downstream of two pulp and paper mills and at upstream references in southern Lake Saimaa, Finland. The mills used elemental chlorine-free bleaching and activated sludge effluent treatment technologies. The exposure of fish to pulp mill effluents, as measured by concentrations of chlorophenolics in the bile and liver ethoxyresorufin-O-deethylase (EROD) activity, was low and almost similar to the references. Nevertheless, bile resin acid concentrations in exposed perch and roach (260-320 micrograms/ml) and bile beta-sitosterol concentrations in exposed roach (1.5-3.5 micrograms/ml) were, respectively, 10 to 30 times and 2 to 5 times higher compared with the references. Reproductive parameters like plasma 17 beta-estradiol and testosterone levels were lower in exposed male and female perch but the same in roach. Vitellogenin concentrations in plasma and liver cytosol of roach were similar. Gonad weight and fecundity were lower in exposed female perch but similar in roach. The relative liver weight was higher in exposed roach but not in perch. The body condition and immunologic parameters in fish were the same. The growth and age at maturity of exposed perch and roach were similar to the references. The size and age distribution of perch in the recipient of one of the mills was shifted toward smaller and younger fish. Our results show that several reproductive variables were altered in late vitellogenic perch in the vicinity of the mills, but they were not altered in roach.

  6. Reduction in recruitment of white bass in Lake Erie after invasion of white perch

    USGS Publications Warehouse

    Madenjian, Charles P.; Knight, Roger L.; Bur, Michael; Forney, John L.

    2000-01-01

    Recruitment to the adult population of white bass Morone chrysops in Lake Erie sharply declined during the early 1980s. To explain this phenomenon, we formulated the following four hypotheses: (1) the biological characteristics of adult spawners changed during the early 1980s, so that the ability to produce eggs decreased; (2) the decrease in phosphorus loadings to Lake Erie during the 1970s resulted in a lower abundance of crustacean zooplankton and thus in reduced survival of age-0 white bass; (3) the increase in the population of adult walleyes Stizostedion vitreum in Lake Erie during the 1970s and 1980s led to reduced survival of age-0 white bass; and (4) establishment of the white perch Morone americana population in Lake Erie during the early 1980s led to reduced survival of the early life stages of white bass. The growth, maturity, and fecundity of adults during the period 1981-1997 were compared with the same characteristics found by earlier studies. The mean length, weight, and condition factors that we calculated were higher than those reported for Lake Erie in 1927-1929 for all age groups examined, and white bass in Lake Erie matured at an earlier age during 1981-1997 than during 1927-1929. Fecundity estimates ranged from 128,897 to 1,049,207 eggs/female and were similar to estimates from other populations. Therefore, the first hypothesis was rejected. With respect to the second hypothesis, zooplankton surveys conducted during 1970 and 1983-1987 indicated that the abundance of crustacean zooplankton in Lake Erie did not change between the two time periods. However, these results were not conclusive because only a single-year survey was conducted before 1980. Based on walleye diet studies and estimates of walleye population size, walleye predation pressure on age-0 white bass in Lake Erie during 1986-1988 was just slightly higher than that during 1979-1981. Thus, such pressure can explain only a minor portion of the reduction in white bass recruitment. To

  7. A bacterial disease of perch (Perca fluviatilis L.) in an alpine lake: isolation and preliminary study of the causative organism.

    PubMed

    Michel, C

    1981-10-01

    An epizootic among perch (Perca fluviatilis L.) occurred during the summer and fall of 1979 in an alpine lake (Lake Annecy, Haute-Savoie) in France. Hemorrhagic and ulcerative clinical signs were associated with the height of the mortality. A Gram-negative, non-motile, slow-growing bacterium was isolated from skin lesions is diseased fish. Aeromonas hydrophila often was present. Since the nonmotile bacterium was suspected to be the etiological agent, its characteristics and pathogenicity were determined. The bacterium was pathogenic to perch, possibly pathogenic to rainbow trout, and non-pathogenic to carp. It could be reisolated from infected fish, but its physiologic and biochemical properties have not been assessed to determine the taxonomic position.

  8. Age, growth, spawning season, and fecundity of the trout-perch (Percopsis omiscomaycus) in southeastern Lake Michigan

    USGS Publications Warehouse

    House, Robert; Wells, LaRue

    1973-01-01

    Growth of trout-perch (Percopsis omiscomaycus) in the first 2 years of life was somewhat slower in southeastern Lake Michigan (average length at end of second year, 83 mm) than in Lower Red Lake, Minnesota (90 mm), but considerably faster than in Lake Superior (58 mm); size differences in later years were slightly less pronounced. Young fish began growing earlier in the year (some before June 20) than older ones (as late as August). Females tended to live longer than males, as they do in Lower Red Lake and Lake Superior. Trout-perch spawned from late June or early July until late September, somewhat later than in Lower Red Lake (May to August) or Lake Erie (June to August). Fecundity was similar to that in Lake Erie; mature females 94-146 mm long contained from 126 to 1329 yolked eggs.

  9. Ocean Fertilization and Ocean Acidification

    NASA Astrophysics Data System (ADS)

    Cao, L.; Caldeira, K.

    2008-12-01

    It has been suggested that ocean fertilization could help diminish ocean acidification. Here, we quantitatively evaluate this suggestion. Ocean fertilization is one of several ocean methods proposed to mitigate atmospheric CO2 concentrations. The basic idea of this method is to enhance the biological uptake of atmospheric CO2 by stimulating net phytoplankton growth through the addition of iron to the surface ocean. Concern has been expressed that ocean fertilization may not be very effective at reducing atmospheric CO2 concentrations and may produce unintended environmental consequences. The rationale for thinking that ocean fertilization might help diminish ocean acidification is that dissolved inorganic carbon concentrations in the near-surface equilibrate with the atmosphere in about a year. If ocean fertilization could reduce atmospheric CO2 concentrations, it would also reduce surface ocean dissolved inorganic carbon concentrations, and thus diminish the degree of ocean acidification. To evaluate this line of thinking, we use a global ocean carbon cycle model with a simple representation of marine biology and investigate the maximum potential effect of ocean fertilization on ocean carbonate chemistry. We find that the effect of ocean fertilization on ocean acidification depends, in part, on the context in which ocean fertilization is performed. With fixed emissions of CO2 to the atmosphere, ocean fertilization moderately mitigates changes in ocean carbonate chemistry near the ocean surface, but at the expense of further acidifying the deep ocean. Under the SRES A2 CO2 emission scenario, by year 2100 simulated atmospheric CO2, global mean surface pH, and saturation state of aragonite is 965 ppm, 7.74, and 1.55 for the scenario without fertilization and 833 ppm, 7.80, and 1.71 for the scenario with 100-year (between 2000 and 2100) continuous fertilization for the global ocean (For comparison, pre-industrial global mean surface pH and saturation state of

  10. Perching of Tengmalm's Owl (Aegolius funereus) Nestlings at the Nest Box Entrance: Effect of Time of the Day, Age, Wing Length and Body Weight

    PubMed Central

    Kouba, Marek; Bartoš, Luděk; Zárybnická, Markéta

    2014-01-01

    The behaviour of the nestlings of nocturnal cavity-nesting species has relatively rarely been studied in detail because of problems connected with use of the technical devices required to provide long-term monitoring of individuals. However, long-term observation of nestling behaviour is crucial in order to identify different types of behaviour which may be caused by sibling competition at the end of nesting period. We studied behaviour of 43 Tengmalm's owl (Aegolius funereus) nestlings at 14 nests using a camera and a chip system. The nestlings perched at the nest box entrance from an average age of 28 days from hatching (range 24–34 days) until fledging, spending around 2 hours per day here in total, in periods ranging from a few seconds to 147 min (7.6±10.9 min, mean ± SD). We found that individual duration of perching at the nest box entrance was significantly influenced by nestlings' age and wing length and that the duration of perching at the nest box entrance significantly decreased with time of night. However, during daylight hours, time of day had no effect on either probability or duration of nestlings' perching. We suggest daylight perching at the nest box entrance results from nestlings' preparation for fledging, while individuals perching here during the night may gain an advantageous position for obtaining food from the parents; another possibility at all times of day is that nestlings can reaffirm their social dominance status by monopolizing the nest box entrance. PMID:24828567

  11. Baseline concentrations of biliary PAH metabolites in perch (Perca fluviatilis) in the open Gulf of Finland and in two coastal areas

    NASA Astrophysics Data System (ADS)

    Vuorinen, Pekka J.; Saulamo, Kari; Lecklin, Tiina; Rahikainen, Mika; Koivisto, Pertti; Keinänen, Marja

    2017-07-01

    Female perch (Perca fluviatilis) were sampled annually in late summer from 2006 to 2009 from the open sea of the eastern Gulf of Finland off Haapasaari island to monitor baseline biliary PAH metabolite concentrations. In addition, two coastal locations were sampled in 2008. PAH metabolite concentrations were compared between the open sea and coastal samples and between the sampling years and examined in relation to the body characteristics of perch. Of the PAH metabolites, only 1-hydroxypyrene (1-OH pyrene) was detected at quantifiable levels in the bile of nearly all perch individuals. There were some annual differences but no temporal trend in the concentration of biliary 1-OH pyrene in perch from Haapasaari. At the coastal locations, 1-OH pyrene concentrations in the bile of perch were significantly higher than in the open sea Haapasaari area, probably due to greater contamination of the coastal sites and differences in feeding behaviour. No correlations between the body characteristics of perch and 1-OH pyrene concentrations were detected. It is concluded that PAH metabolites in the bile of fish could be measured in the Gulf of Finland to detect oil spills in the open sea, and the cost-effective total fluorescence method could be used in such monitoring programmes.

  12. Spatial variability of mercury and polyunsaturated fatty acids in the European perch (Perca fluviatilis) - Implications for risk-benefit analyses of fish consumption.

    PubMed

    Strandberg, Ursula; Palviainen, Marjo; Eronen, Aslak; Piirainen, Sirpa; Laurén, Ari; Akkanen, Jarkko; Kankaala, Paula

    2016-12-01

    This study evaluated the spatial variability of risks and benefits of consuming fish from humic and clear lakes. Mercury in fish is a potential risk for human health, but risk assessment may be confounded by selenium, which has been suggested to counterbalance mercury toxicity. In addition to the risks, fish are also rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are known to be beneficial for cardiovascular health and brain cognitive function in humans. We found that the concentrations of EPA + DHA and mercury in European perch (Perca fluviatilis) vary spatially and are connected with lake water chemistry and catchment characteristics. The highest mercury concentrations and the lowest EPA + DHA concentrations were found in perch from humic lakes with high proportion of peatland (30-50%) in the catchment. In addition, the ratio of selenium to mercury in perch muscle was ≥1 suggesting that selenium may counterbalance mercury toxicity. The observed variation in mercury and EPA + DHA content in perch from different lakes indicate that the risks and benefits of fish consumption vary spatially, and are connected with lake water chemistry and catchment characteristics. In general, consumption of perch from humic lakes exposed humans to greater risks (higher concentrations of mercury), but provided less benefits (lower concentrations of EPA + DHA) than consumption of perch from clear lakes.

  13. Probing Microbial Activity in a Perched Water Body Located in a Deep Vadose Zone

    NASA Astrophysics Data System (ADS)

    Fujita, Y.; Taylor, J. L.; Henriksen, J. R.; Delwiche, M.; Gebrehiwet, T.; Hubbard, S. S.; Spycher, N.; Weathers, T. S.; Ginn, T. R.; Pfiffner, S. M.; Smith, R. W.

    2011-12-01

    Waste releases to the vadose zone are a legacy of past activities at a number of Department of Energy (DOE) facilities. At the Idaho National Laboratory (INL), 90Sr has been detected in perched water bodies underlying the Idaho Nuclear Technology and Engineering Center (INTEC) facility. Microbially induced calcite precipitation (MICP) using urea-hydrolyzing microbes is one proposed approach for immobilization of 90Sr in the subsurface. The sequestration mechanism is co-precipitation in calcite, promoted by the production of carbonate alkalinity from ureolysis. In order to assess the potential efficacy of MICP at INTEC a field study was conducted at the INL Vadose Zone Research Park (VZRP). The VZRP is located approximately 3 km from INTEC and shares many of the same hydrologic and lithologic features but in a non-contaminated setting. We conducted experiments over two field seasons in a perched water body located approximately 15 meters below land surface, using a 5-spot wellfield design. During the first season amendments (molasses and urea) were injected into the central well and water was extracted from two wells on either side, located along a diagonal. Water samples were characterized for microbial abundance, ureolytic activity and ureC gene numbers, along with solution composition. Before, during and after the injections cross-borehole geophysical imaging was performed, using various combinations of the available wells. During the second field season in situ static experiments were conducted to specifically characterize attached and unattached microbial communities, using surrogate substrates colonized during a 12 week incubation. Based on the field data a first order in situ urea hydrolysis rate constant of 0.034 d-1 was estimated. This was more than an order of magnitude higher than rate constants estimated above-ground using water samples, suggesting that attached microorganisms were responsible for >90% of the observed urea hydrolysis activity. The

  14. Distribution and exploitation of Nile perch Lates niloticus in relation to stratification in Lake Victoria, East Africa

    USGS Publications Warehouse

    Taabu-Munyaho, A.; Kayanda, Robert J.; Everson, Inigo; Grabowski, Timothy B.; Marteinsdóttir, Gudrún

    2013-01-01

    Stratification restricts habitable areas forcing fish to balance between favourable temperature and minimum dissolved oxygen requirements. Acoustic surveys conducted during the stratified and isothermal periods on tropical Lake Victoria indicated that stratification of temperature and dissolved oxygen (DO) affected vertical distribution of Nile perch. There was higher mean temperature (25.6 ± 0.5 °C) and lower DO (6.4 ± 1.8 mg/l) during stratified period compared to the isothermal period (mean temperature 24.9 ± 0.3 °C; mean DO 7.3 ± 0.6 mg/l). Higher mean densities of Nile perch were recorded in the coastal (0.44 ± 0.03) and deep (0.27 ± 0.02 g/m3) strata during the stratified compared to the isothermal season (coastal: 0.24 ± 0.01; deep: 0.12 ± 0.02 g/m3). In addition, Nile perch density in the upper 0–40 m depth layers in the coastal and deep strata increased by over 50% from the isothermal to the stratified season. Daily landings from 65 motorised fishing boats between October 2008 and September 2010 show higher mean catch (26.29 ± 0.17 kg/boat/day) during stratified compared to the isothermal (23.59 ± 0.15) season. Thermal stratification apparently compresses the habitat available to Nile perch and can potentially result in higher exploitation. Managers should evaluate the potential benefits of instituting closed seasons during the stratified period, and stock assessment models should take into account the seasonal niche compression.

  15. Assessing accumulation and biliary excretion of naphthenic acids in yellow perch exposed to oil sands-affected waters.

    PubMed

    van den Heuvel, Michael R; Hogan, Natacha S; MacDonald, Gillian Z; Berrue, Fabrice; Young, Rozlyn F; Arens, Collin J; Kerr, Russell G; Fedorak, Phillip M

    2014-01-01

    Naphthenic acids are known to be the most prevalent group of organic compounds in oil sands tailings-associated waters. Yellow perch (Perca flavescens) were exposed for four months to oil sands-influenced waters in two experimental systems located on an oil sands lease 30 km north of Fort McMurray Alberta: the Demonstration Pond, containing oil sands tailings capped with natural surface water, and the South Bison Pond, integrating lean oil sands. Yellow perch were also sampled from three lakes: Mildred Lake that receives water from the Athabasca River, Sucker Lake, at the edge of oil sands extraction activity, and Kimowin Lake, a distant reference site. Naphthenic acids were measured in perch muscle tissue using gas chromatography-mass spectrometry (GC-MS). Bile metabolites were measured by GC-MS techniques and by high performance liquid chromatography (HPLC) with fluorescence detection at phenanthrene wavelengths. A method was developed using liquid chromatography-high resolution mass spectrometry (LC-HRMS) to evaluate naphthenic acids in bile. Tissue analysis did not show a pattern of naphthenic acids accumulation in muscle tissue consistent with known concentrations in exposed waters. Bile fluorescence and LC-HRMS methods were capable of statistically distinguishing samples originating from oil sands-influenced waters versus reference lakes. Although the GC-MS and HPLC fluorescence methods were correlated, there were no significant correlations of these methods and the LC-HRMS method. In yellow perch, naphthenic acids from oil sands sources do not concentrate in tissue at a measurable amount and are excreted through a biliary route. LC-HRMS was shown to be a highly sensitive, selective and promising technique as an indicator of exposure of biota to oil sands-derived naphthenic acids.

  16. Myxobolus neurophilus Guilford 1963 (Myxosporea: Myxobolidae): a common parasite infecting yellow perch Perca flavescens (Mitchell, 1814) in Saskatchewan, Canada.

    PubMed

    Scott, S J; Griffin, M J; Quiniou, S; Khoo, L; Bollinger, T K

    2015-04-01

    The goal of this study was to identify a myxosporidian parasite infecting the central nervous system of yellow perch Perca flavescens (Mitchell, 1814) observed while investigating a fish kill in Saskatchewan, Canada. Fish were collected from seven different lakes, from two distinct watersheds. Sixty-four per cent (54/86) of yellow perch contained myxozoan pseudocysts located throughout the spinal cord and brain. Myxospores measured 16.5 μm (range 16.2-16.8) long and 8.2 μm (range 7.9-8.4) wide and contained two pyriform, mildly dissymmetrical, polar capsules measuring 7.7 μm (range 7.3-8.1) long and 2.7 μm (range 2.4-3.0) wide. The polar capsules each contained a single polar filament, with 7-9 turns per polar filament coil. Sequencing of the 18S SSU rDNA gene demonstrated >99% similarity to Myxobolus neurophilus. In 60% of infected fish, there was a mild to moderate, non-suppurative myelitis or encephalitis, or both, associated with myxospores. Axonal degeneration was present in rare cases. These findings extend the geographical distribution of M. neurophilus and suggest it may be widespread in yellow perch populations in Saskatchewan. © 2014 John Wiley & Sons Ltd.

  17. Data Management and Data Quality in PERCH, a Large International Case-Control Study of Severe Childhood Pneumonia.

    PubMed

    Watson, Nora L; Prosperi, Christine; Driscoll, Amanda J; Higdon, Melissa M; Park, Daniel E; Sanza, Megan; DeLuca, Andrea N; Awori, Juliet O; Goswami, Doli; Hammond, Emily; Hossain, Lokman; Johnson, Catherine; Kamau, Alice; Kuwanda, Locadiah; Moore, David P; Neyzari, Omid; Onwuchekwa, Uma; Parker, David; Sapchookul, Patranuch; Seidenberg, Phil; Shamsul, Arifin; Siazeele, Kazungu; Srisaengchai, Prasong; Sylla, Mamadou; Levine, Orin S; Murdoch, David R; O'Brien, Katherine L; Wolff, Mark; Deloria Knoll, Maria

    2017-06-15

    The Pneumonia Etiology Research for Child Health (PERCH) study is the largest multicountry etiology study of pediatric pneumonia undertaken in the past 3 decades. The study enrolled 4232 hospitalized cases and 5325 controls over 2 years across 9 research sites in 7 countries in Africa and Asia. The volume and complexity of data collection in PERCH presented considerable logistical and technical challenges. The project chose an internet-based data entry system to allow real-time access to the data, enabling the project to monitor and clean incoming data and perform preliminary analyses throughout the study. To ensure high-quality data, the project developed comprehensive quality indicator, data query, and monitoring reports. Among the approximately 9000 cases and controls, analyzable laboratory results were available for ≥96% of core specimens collected. Selected approaches to data management in PERCH may be extended to the planning and organization of international studies of similar scope and complexity. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

  18. Effects of chlorpyrifos ethyl on acetylcholinesterase activity in climbing perch cultured in rice fields in the Mekong Delta, Vietnam.

    PubMed

    Nguyen, Tam Thanh; Berg, Håkan; Nguyen, Hang Thi Thuy; Nguyen, Cong Van

    2015-07-01

    Climbing perch is commonly harvested in rice fields and associated wetlands in the Mekong Delta. Despite its importance in providing food and income to local households, there is little information how this fish species is affected by the high use of pesticides in rice farming. Organophosphate insecticides, such as chlorpyrifos ethyl, which are highly toxic to aquatic organisms, are commonly used in the Mekong Delta. This study shows that the brain acetylcholinesterase (AChE) activity in climbing perch fingerlings cultured in rice fields, was significantly inhibited by a single application of chlorpyrifos ethyl, at doses commonly applied by rice farmers (0.32-0.64 kg/ha). The water concentration of chlorpyrifos ethyl decreased below the detection level within 3 days, but the inhibition of brain AChE activity remained for more than 12 days. In addition, the chlorpyrifos ethyl treatments had a significant impact on the survival and growth rates of climbing perch fingerlings, which were proportional to the exposure levels. The results indicate that the high use of pesticides among rice farmers in the Mekong Delta could have a negative impact on aquatic organisms and fish yields, with implications for the aquatic biodiversity, local people's livelihoods and the aquaculture industry in the Mekong Delta.

  19. Relationship between mercury accumulation in young-of-the-year yellow perch and water-level fluctuations

    USGS Publications Warehouse

    Sorensen, J.A.; Kallemeyn, L.W.; Sydor, M.

    2005-01-01

    A three-year (2001 -2003) monitoring effort of 14 northeastern Minnesota lakes was conducted to document relationships between water-level fluctuations and mercury bioaccumulation in young-of-the-year (YOY) yellow perch (Perca flavescens) collected in the fall of each year at fixed locations. Six of those lakes are located within or adjacent to Voyageurs National Park and are influenced by dams on the outlets of Rainy and Namakan lakes. One site on Sand Point Lake coincides with a location that has nine years of previous monitoring suitable for addressing the same issue over a longer time frame. Mean mercury concentrations in YOY yellow perch at each sampling location varied significantly from year to year. For the 12-year monitoring site on Sand Point Lake, values ranged from 38 ng gww-1 in 1998 to 200 ng gww -1 in 2001. For the 14-lake study, annual mean concentrations ranged by nearly a factor of 2, on average, for each lake over the three years of record. One likely factor responsible for these wide variations is that annual water-level fluctuations are strongly correlated with mercury levels in YOY perch for both data sets. ?? 2005 American Chemical Society.

  20. Application of HEC-RAS for flood forecasting in perched river-A case study of hilly region, China

    NASA Astrophysics Data System (ADS)

    Sun, Pingping; Wang, Shuqian; Gan, Hong; Liu, Bin; Jia, Ling

    2017-04-01

    Flooding in small and medium rivers are seriously threatening the safety of human beings’ life and property. The simulation forecasting of the river flood and bank risk in hilly region has gradually become a hotspot. At present, there are few studies on the simulation of hilly perched river, especially in the case of lacking section flow data. And the method of how to determine the position of the levee breach along the river bank is not much enough. Based on the characteristics of the sections in hilly perched river, an attempt is applied in this paper which establishes the correlation between the flow profile computed by HEC-RAS model and the river bank. A hilly perched river in Lingshi County, Shanxi Province of China, is taken as the study object, the levee breach positions along the bank are simulated under four different design storm. The results show that the flood control standard of upper reach is high, which can withstand the design storm of 100 years. The current standard of lower reach is low, which is the flooding channel with high frequency. As the standard of current channel between the 2rd and the 11th section is low, levee along that channel of the river bank is considered to be heighten and reinforced. The study results can provide some technical support for flood proofing in hilly region and some reference for the reinforcement of river bank.

  1. Relationship between individual variation in morphological characters and swimming costs in brook charr (Salvelinus fontinalis) and yellow perch (Perca flavescens).

    PubMed

    Boily, Patrice; Magnan, Pierre

    2002-04-01

    The objective of this study was to examine if individual variation in morphological characters is related to swimming costs in wild and domestic brook charr, and in wild yellow perch. Our results indicate that absolute swimming cost was higher in wild and domestic brook charr individuals having a stout body shape, and these individuals are therefore less efficient swimmers. These results are consistent with field observations that described relationships between individual variation in morphology and habitat use in salmonids. Further analyses indicated that standard metabolic rates were higher in individuals having a stout body shape, and that net swimming cost was not related to body shape. Accordingly, the higher swimming cost of stout individuals is probably an indirect consequence of an increase in standard metabolic rate. In wild yellow perch, absolute and net swimming costs were higher in individuals having a stout body shape and a low aspect caudal fin, and standard metabolic rate was not related to body shape. Therefore, in contrast to brook charr, individual variation in the swimming cost of yellow perch appears to be related to morphological characters that affect drag and thrust forces, which is consistent with previously published inter-specific observations.

  2. Timing, Frequency and Environmental Conditions Associated with Mainstem–Tributary Movement by a Lowland River Fish, Golden Perch (Macquaria ambigua)

    PubMed Central

    Koster, Wayne M.; Dawson, David R.; O’Mahony, Damien J.; Moloney, Paul D.; Crook, David A.

    2014-01-01

    Tributary and mainstem connections represent important links for the movement of fish and other biota throughout river networks. We investigated the timing, frequency and environmental conditions associated with movements by adult golden perch (Macquaria ambigua) between the mainstem of the mid-Murray River and a tributary, the Goulburn River, in south-eastern Australia, using acoustic telemetry over four years (2007–2011). Fish were tagged and released in autumn 2007–2009 in the mid-Murray (n = 42) and lower Goulburn (n = 37) rivers within 3–6 km of the mid-Murray-lower Goulburn junction. 38% of tagged fish undertook mainstem–tributary movements, characterised mostly by temporary occupation followed by return of fish to the original capture river. Approximately 10% of tagged fish exhibited longer-term shifts between the mainstem and tributary. Movement of fish from the tributary into the mainstem occurred primarily during the spawning season and in some years coincided with the presence of golden perch eggs/larvae in drift samples in the mainstem. Many of the tributary-to-mainstem movements occurred during or soon after changes in flow. The movements of fish from the mainstem into the tributary were irregular and did not appear to be associated with spawning. The findings show that golden perch moved freely across the mainstem–tributary interface. This demonstrates the need to consider the spatial, behavioural and demographic interdependencies of aquatic fauna across geographic management units such as rivers. PMID:24788137

  3. Aerial perches and free-range laying hens: the effect of access to aerial perches and of individual bird parameters on keel bone injuries in commercial free-range laying hens.

    PubMed

    Donaldson, C J; Ball, M E E; O'Connell, N E

    2012-02-01

    The aim of this trial was to determine the effect of aerial perches on keel bone injuries and tibia bone characteristics in free-range laying hens. The relationship between keel bone injuries and individual bird parameters, such as weight, girth, wing:girth ratio, feather coverage, and tibia bone characteristics, was also assessed. Five commercial free-range houses, each containing between 7,000 and 8,000 birds, were used. The houses and range areas were divided in half; in half of the house, birds had access to aerial perches (P) and in the other half, they did not (NP). On 13 occasions between 17 and 70 wk of age, 20 birds per treatment were randomly selected from the slatted area and palpated for keel bone injury. At 72 wk of age, 30 birds per treatment in each of 4 houses were selected at random, weighed, and then euthanized. Girth and wing area and feather coverage were measured. The keel and left tibia bones were removed and keel bones were scored for injury. Tibia bones were weighed and diameter, length, breaking strength, and ash content recorded. Results indicated that access to aerial perches did not affect tibia bone measures (P > 0.05). Average palpated keel bone score increased with age of the hens (P < 0.001) but was not significantly affected by perch treatment (P > 0.05). There was a significant interaction between treatment and farm on keel bone injuries measured at dissection (P < 0.05), with the probability of birds having high keel-damage scores increasing in the perched treatment in some farms but not others. In general, as the keel bone injury score measured at dissection increased, the breaking strength (P < 0.001) and ash content (P < 0.05) of the tibia bone decreased. It is suggested that individual variation in bone strength contributes to differences in susceptibility to keel injury. No relationship existed between keel-injury score measured at dissection and individual parameters, such as weight, girth, or wing:girth ratio (P > 0

  4. Spotlight on fish: light pollution affects circadian rhythms of European perch but does not cause stress.

    PubMed

    Brüning, Anika; Hölker, Franz; Franke, Steffen; Preuer, Torsten; Kloas, Werner

    2015-04-01

    Flora and fauna evolved under natural day and night cycles. However, natural light is now enhanced by artificial light at night, particularly in urban areas. This alteration of natural light environments during the night is hypothesised to alter biological rhythms in fish, by effecting night-time production of the hormone melatonin. Artificial light at night is also expected to increase the stress level of fish, resulting in higher cortisol production. In laboratory experiments, European perch (Perca fluviatilis) were exposed to four different light intensities during the night, 0 lx (control), 1 lx (potential light level in urban waters), 10 lx (typical street lighting at night) and 100 lx. Melatonin and cortisol concentrations were measured from water samples every 3h during a 24 hour period. This study revealed that the nocturnal increase in melatonin production was inhibited even at the lowest light level of 1 lx. However, cortisol levels did not differ between control and treatment illumination levels. We conclude that artificial light at night at very low intensities may disturb biological rhythms in fish since nocturnal light levels around 1 lx are already found in urban waters. However, enhanced stress induction could not be demonstrated. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Early life history of the yellow perch, Perca flavescens (Mitchill), in the Red Lakes, Minnesota

    USGS Publications Warehouse

    Pycha, Richard L.; Smith, Lloyd L.

    1955-01-01

    The early life history of the yellow perch, an important commercial species in the Red Lakes, Minnesota, has been studied with special reference to length at scale formation, growth rate during first season of life, and food habits as they relate to growth and survival. Scales are fully imbricated in the area of 12th to 14th lateral line scales at 24 millimeters total length. There is a wide annual varition in first season's growth which is not correlated with growth in older fish. Body-scale relationship is rectilinear from 24 to 280 millimeters. Length-weight relationship during the first year is expressed by the equation W = 0.6198 × 10−5 L3.1251 which is very similar to that describing the relationship in later years. Stomach analysis indicates food is primarily plankton but in some seasons fish may be strongly dependent on bottom forms. Variations in food availability appear to be associated with changes in growth and may have a major influence on survival.

  6. The complete mitochondrial genome of jade perch, Scortum barcoo (Perciformes: Terapontidae: Scortum).

    PubMed

    Liu, Chun; Li, Kaibin; Wang, Qing; Wang, Fang; Zeng, Weiwei; Mai, Xiaomei; Wu, Shuqin

    2016-09-01

    This is the first documentation of the complete mitochondrial genome sequence of the jade perch, Scortum barcoo. The 16,843 bp mitogenome containes 37 genes (13 protein-coding genes, 22 transfer RNA genes, and 2 ribosomal RNA genes) and two main non-coding regions (the control region and the origin of the light strand replication) as do other vertebrate mitogenomes. The overall base composition of S. barcoo is 27.39% for A, 24.74% for T, 31.14% for C and 16.73% for G, with a slight A + T bias of 52.13%. All protein-coding genes are initiated with ATG except for COX1, which begin with GTG instead. Meanwhile, the termination codons of 13 protein-coding genes are varied with TAA, TAG, TA, T or AGG. The measure of complete mitogenome sequence of S. barcoo will provide fundamental data for the phylogenetic and biogeographic studies of the Terapontidae.

  7. A Red-Tailed Hawk perches on a stump at KSC.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This red-tailed hawk on the roadside at Kennedy Space Center appears to be eyeing the photographer. The red-tailed hawk has a stocky build and broad, rounded wings. Its wide range covers Alaska and Nova Scotia south to Panama. It can frequently be seen perched in a tree at the edge of a meadow, watching for movement in the grass below. It feeds mainly on small rodents. The Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects. Kennedy Space Center shares a boundary with the Merritt Island National Wildlife Refuge, encompassing 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  8. Functional integrity of the interrenal tissue of yellow perch from contaminated sites tested in vivo

    SciTech Connect

    Girard, C.; Brodeur, J.C.; Hontela, A.

    1995-12-31

    The normal activation of the hypothalamo-pituitary-interrenal axis (HPI axis) in response to capture is disrupted in fish subjected to life-long exposure to heavy metals, PCBs and PAHs. The ability to increase plasma cortisol in yellow perch (Perca flavescens) from sites contaminated by heavy metals and organic compounds, and from a reference site was assessed by the Capture stress test and by the ACTH Challenge test, a new standardized in vivo method designed for field studies. The effects of seasonal factors, such as temperature and gonadal maturity on these tests were investigated. Measures of liver and muscle glycogen and histopathology were made to further characterize the biochemical and structural changes that may occur along with hormonal changes. The Capture stress test showed that an acute source of stress induced a lower cortisol response in fish from the highly contaminated site compared to the reference site, revealing a functional impairment of the HPI axis. The ACTH Challenge test showed that the hormonal responsiveness of the cortisol-secreting interrenal tissue, stimulated by a standard dose of ACTH injected i.p., was lower in fish from the highly contaminated site than the reference site. Spring is the season during which the impairment was the most evident. The possibility of using the reduced capacity of feral fish to respond to a standardized ACTH Challenge as an early bioindicator of toxic stress is discussed.

  9. A Red-Tailed Hawk perches on a stump at KSC.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This red-tailed hawk on the roadside at Kennedy Space Center appears to be eyeing the photographer. The red-tailed hawk has a stocky build and broad, rounded wings. Its wide range covers Alaska and Nova Scotia south to Panama. It can frequently be seen perched in a tree at the edge of a meadow, watching for movement in the grass below. It feeds mainly on small rodents. The Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects. Kennedy Space Center shares a boundary with the Merritt Island National Wildlife Refuge, encompassing 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  10. Genetic variability and glacial origins of yellow perch (Perca flavescens) in North America

    USGS Publications Warehouse

    Todd, Thomas N.; Hatcher, Charles O.

    1993-01-01

    Starch–gel electrophoresis was used to analyze muscle and liver tissue for variation in 13 enzymes representing 31 presumptive loci in yellow perch (Perca flavescens) from 13 localities scattered throughout the natural geographic range of the species in North America. Ten loci were polymorphic, but only three, alcohol dehydrogenase (ADH-1*), glucose-6-phosphate isomerase (GPI-1*), and phosphoglucomutase (PGM-2*), exhibited polymorphisms at relatively high frequencies across localities. Western populations were fixed for one allele at ADH-1*, eastern populations were fixed for another allele, and populations from intermediate locations in Lake Ontario and Pennsylvania had both alleles. The distributions of alleles at GPI-1* and PGM-2*were similar to that of ADH-1*, exhibiting strong differences between eastern and western populations, although the delineation was not as clear. Western populations were much less variable than eastern populations, and the distribution of alleles indicated that the two groups were derived from Mississippi and Atlantic glacial refugia. Populations near the physiographic discontinuity between the Mississippi and Atlantic drainages in western New York and Pennsylvania exhibited an admixture of typically western and eastern alleles. Such observations are consistent with the mixed faunal history of the region and limited postglacial dispersal of western and eastern populations across the boundary.

  11. An artificial perch to help Snail Kites handle an exotic Apple Snail

    USGS Publications Warehouse

    Pias, Kyle E.; Welch, Zach C.; Kitchens, Wiley M.

    2012-01-01

    In the United States, the Snail Kite (Rostrhamus sociabilis plumbeus) is a federally endangered species and restricted to the wetlands of south-central Florida where the current population numbers less than 1,500. The Snail Kite is an extreme dietary specialist, previously feeding almost exclusively on one species of snail, the Florida Apple Snail (Pomacea paludosa). Within the past decade, an exotic species of apple snail, the Island Apple Snail (Pomacea insularum), has become established on lakes in central Florida. Island Apple Snails are larger than the native Florida Apple Snails, and Snail Kites handle the exotic snails less efficiently. Juvenile Snail Kites, in particular, have lower daily energy balances while feeding on Island Apple Snails. An inexpensive, easy-to-construct platform was developed that would provide Snail Kites with a flat, stable surface on which to extract snails. The platform has the potential to reduce the difficulties Snail Kites experience when handling exotic snails, and may benefit the Snail Kite population as a whole. Initial observations indicate that Snail Kites use the platforms frequently, and snails extracted at the platforms are larger than snails extracted at other perches.

  12. Effects of freezing on white perch Morone americana (Gmelin, 1789): Implications for multivariate morphometrics

    USGS Publications Warehouse

    Kocovsky, Patrick

    2016-01-01

    This study tested the hypothesis that duration of freezing differentially affects whole-body morphometrics of a derived teleost. Whole-body morphometrics are frequently analyzed to test hypotheses of different species, or stocks within a species, of fishes. Specimens used for morphometric analyses are typically fixed or preserved prior to analysis, yet little research has been done on how fixation or preservation methods or duration of preservation of specimens might affect outcomes of multivariate statistical analyses of differences in shape. To determine whether whole-body morphometrics changed as a result of freezing, 23 whole-body morphometrics of age-1 white perch (Morone americana) from western Lake Erie (n = 211) were analyzed immediately after capture, after being held on ice overnight, and after freezing for 100 or 200 days. Discriminant function analysis revealed that all four groups differed significantly from one another (P < 0.0001). The first canonical axis reflected long-axis morphometrics, where there was a clear pattern of positive translation along this axis with duration of preservation. Re-classification analysis demonstrated fish were typically assigned to their original preservation class except for fish frozen 100 days, which assigned mostly to frozen 200 days. Morphometric comparisons using frozen fish must be done on fish frozen for identical periods of time to avoid biases related to the length of time they were frozen. Similar experiments should be conducted on other species and also using formalin- and alcohol-preserved specimens.

  13. Oceanic Observations

    NASA Technical Reports Server (NTRS)

    Busalacchi, Antonio J.

    1997-01-01

    For many years, merchant ships and the naval fleets of various countries have been the major source of data over and in the open ocean. Oceanographic research experiments and process studies in the field have also contributed to the climatological data bases for the global ocean, but, for the most part, these have been limited in duration and extent. However, over the last 10 years under the auspices of the World Climate Research Program and the International Geosphere Biosphere Program the role of the oceans in global and climate change has taken on increased significance. This has created a need for a considerably improved understanding of the seasonal, interannual, decadal and longer time-scale variability of the physical and biogeochemical attributes of the global ocean. As a result, over the past 10 years several major international field programs have been implemented and have had a tremendous impact on the number of in situ observations obtained for the global ocean. The Tropical Ocean Global Atmosphere (TOGA) program, the World Ocean Circulation Experiment (WOCE), and the Joint Global Ocean Flux Study (JGOFS) were designed with observational, modelling, and process study components aimed at analyzing different aspects of the ocean's role in the coupled climate system. In parallel with the field programs, continuous space-based observations of sea surface temperature, sea surface topography, and sea surface winds spanning nearly a decade or longer have become a reality. During this same time period, numerical ocean models and computational power have advanced to the point where the oceanographic observations, both in situ and remotely sensed, can be assimilated into numerical ocean models in order to provide a four-dimensional (x-y-z-t) depiction of the evolving state of the global ocean.

  14. Design of nest access grids and perches in front of the nests: Influence on the behavior of laying hens.

    PubMed

    Stämpfli, K; Buchwalder, T; Fröhlich, E K F; Roth, B A

    2013-04-01

    In aviary systems for laying hens, it is important to provide suitable nest access platforms in front of the nests, allowing hens to reach and explore each of the nests easily. This access platform is needed to achieve good nest acceptance by the hens and thereby prevent mislaid eggs. In the present experiment, the behavior of hens using 2 different nest access platforms, a plastic grid and 2 wooden perches, was examined. Furthermore, the nests were placed on both sides of the aviary rack (corridor side and outdoor side), either integrated into the aviary rack itself (integrated nest; IN) or placed on the walls of the pens (wall nest; WN), resulting in a 2 × 2 factorial design Four thousand five hundred white laying hens were housed in 20 test pens. The eggs in the nests and mislaid eggs were collected daily, and the behavior of hens on the nest accesses was filmed during wk 25 and 26, using focal observation and scan sampling methods. More balancing, body contact, and agonistic interactions were expected for nests with perches, whereas more walking and nest inspections were expected for nests with grids. There were more mislaid eggs and balancing found in pens equipped with nests with wooden perches. More agonistic interactions and balancing, less standing, and a longer duration of nest inspection were found with the WN compared with the IN. Interactions between platform design and position of the nests were found for duration of nest visits, body contact, and walking, with the highest amount for WN equipped with plastic grids. Nests on the corridor side were favored by the hens. Nest-related behaviors, such as nest inspection, standing, and walking, decreased over time as did the number of hens on the nest accesses, whereas sitting increased. These results indicate that the hens had more difficulties in gripping the perches as designed. The lower number of hens on the nest access platforms in front of IN may be due to a better distribution around nests and tier

  15. CO2-induced ocean acidification increases anxiety in rockfish via alteration of GABAA receptor functioning.

    PubMed

    Hamilton, Trevor James; Holcombe, Adam; Tresguerres, Martin

    2014-01-22

    The average surface pH of the ocean is dropping at a rapid rate due to the dissolution of anthropogenic CO2, raising concerns for marine life. Additionally, some coastal areas periodically experience upwelling of CO2-enriched water with reduced pH. Previous research has demonstrated ocean acidification (OA)-induced changes in behavioural and sensory systems including olfaction, which is due to altered function of neural gamma-aminobutyric acid type A (GABAA) receptors. Here, we used a camera-based tracking software system to examine whether OA-dependent changes in GABAA receptors affect anxiety in juvenile Californian rockfish (Sebastes diploproa). Anxiety was estimated using behavioural tests that measure light/dark preference (scototaxis) and proximity to an object. After one week in OA conditions projected for the next century in the California shore (1125 ± 100 µatm, pH 7.75), anxiety was significantly increased relative to controls (483 ± 40 µatm CO2, pH 8.1). The GABAA-receptor agonist muscimol, but not the antagonist gabazine, caused a significant increase in anxiety consistent with altered Cl(-) flux in OA-exposed fish. OA-exposed fish remained more anxious even after 7 days back in control seawater; however, they resumed their normal behaviour by day 12. These results show that OA could severely alter rockfish behaviour; however, this effect is reversible.

  16. CO2-induced ocean acidification increases anxiety in Rockfish via alteration of GABAA receptor functioning

    PubMed Central

    Hamilton, Trevor James; Holcombe, Adam; Tresguerres, Martin

    2014-01-01

    The average surface pH of the ocean is dropping at a rapid rate due to the dissolution of anthropogenic CO2, raising concerns for marine life. Additionally, some coastal areas periodically experience upwelling of CO2-enriched water with reduced pH. Previous research has demonstrated ocean acidification (OA)-induced changes in behavioural and sensory systems including olfaction, which is due to altered function of neural gamma-aminobutyric acid type A (GABAA) receptors. Here, we used a camera-based tracking software system to examine whether OA-dependent changes in GABAA receptors affect anxiety in juvenile Californian rockfish (Sebastes diploproa). Anxiety was estimated using behavioural tests that measure light/dark preference (scototaxis) and proximity to an object. After one week in OA conditions projected for the next century in the California shore (1125 ± 100 µatm, pH 7.75), anxiety was significantly increased relative to controls (483 ± 40 µatm CO2, pH 8.1). The GABAA-receptor agonist muscimol, but not the antagonist gabazine, caused a significant increase in anxiety consistent with altered Cl− flux in OA-exposed fish. OA-exposed fish remained more anxious even after 7 days back in control seawater; however, they resumed their normal behaviour by day 12. These results show that OA could severely alter rockfish behaviour; however, this effect is reversible. PMID:24285203

  17. Interspecies differences in the accumulation of tributyltin and its metabolites under dietary exposure in sea perch, Lateolabrax japonicus, and red sea bream, Pagrus major.

    PubMed

    Uno, Seiichi; Murakami, Masayo; Kokushi, Emiko; Koyama, Jiro

    2011-02-01

    Interspecies differences in the accumulation of dietary tributyltin (TBT) between sea perch, Lateolabrax japonicus, and red sea bream, Pagrus major, were studied. Although TBTs in both species reached steady-state condition in low-concentration group (L-group, 200 ng/g nominal concentration) by 1 week, it increased up to the end of exposure in high-concentration group (H-group, 3000 ng/g nominal concentration). In H-group, the accumulation rate of TBT in sea perch from 1 to 2 weeks was much higher than in red sea bream, which were 2.4-fold for sea perch and 1.7-fold for red sea bream, although TBT concentrations were similar between sea perch and red sea bream in L-group. Furthermore, in the H-group, the concentrations of TBT at 1 and 2 weeks were about 1.3- and 1.9-fold, respectively, higher in the sea perch than in the red sea bream. On the other hand, DBT residue in red sea bream was about 1.4-fold higher in sea perch for the L-group but concentrations were similar in both fishes for the H-group. These results suggest that red sea bream could metabolize faster the TBT to DBT than sea perch. This study also reveals that fish probably could absorb TBT through the food chain. The uptake of TBT by fish should be regarded in the real environment, because TBT concentration in seawater has been decreasing and now already at significantly low level. Copyright © 2009 Wiley Periodicals, Inc.

  18. Brain acetylcholinesterase activity in shiner perch (Cymatogaster aggregata) and juvenile chinook salmon (Oncorhynchus tshawytscha) after application of carbaryl to control burrowing shrimp within Willapa Bay, Washington.

    PubMed

    Troiano, Alexandra T; King, Kerensa A; Grue, Christian E; Grassley, James M; Ekblad, Cathy J

    2013-11-01

    Carbaryl has been applied in Willapa Bay, Washington, for five decades to control burrowing shrimp (Neotrypaea californiensis and Upogebia pugettensis) on commercial oyster (Crassostrea gigas) beds. Concerns about effects on nontarget species, including fishes, have led to restrictions in use despite a lack of data on in situ exposure. We measured brain acetylcholinesterase (AChE) activity in adult Shiner perch (Cymatogaster aggregata) and juvenile Chinook salmon (Oncorhynchus tshawytscha) after operational applications. We hypothesized that exposure in Shiner perch would be greater than in juvenile Chinook salmon because of their greater site fidelity and benthic foraging. However, Shiner perch exhibited no statistically significant AChE inhibition. Enzyme activity was statistically decreased (≤14 %) in juvenile Chinook salmon after a second spray event; however, inhibition was less than that associated with overt effects and was similar to controls by 48 h after the spray. Diet analyses confirmed that Shiner perch were primarily feeding on benthic invertebrates and that juvenile Chinook salmon were feeding primarily within the water column. Composition of Shiner perch diets and amount of food consumed varied little among channels and time periods; however, Shiner perch on beds consumed more food 6 h after application than those at other time points and locations. There were no consistent differences in the diets of juvenile Chinook salmon within channels among time periods. Results suggest (1) that carbaryl applications pose little hazard to fish in the bay having habitat and dietary preferences similar to those of Shiner perch and juvenile Chinook salmon and (2) that quantification of direct exposure in the field is essential to adequately assess risk.

  19. Effects of anesthesia and surgery on serial blood gas values and lactate concentrations in yellow perch (Perca flavescens), walleye pike (Sander vitreus), and koi (Cyprinus carpio).

    PubMed

    Hanley, Christopher S; Clyde, Victoria L; Wallace, Roberta S; Paul-Murphy, Joanne; Patterson, Tamatha A; Keuler, Nicholas S; Sladky, Kurt K

    2010-05-15

    OBJECTIVE-To evaluate serial blood gas values and lactate concentrations in 3 fish species undergoing surgery and to compare blood lactate concentrations between fish that survived and those that died during the short-term postoperative period. DESIGN-Prospective cohort study. Animals-10 yellow perch, 5 walleye pike, and 8 koi. PROCEDURES-Blood samples were collected from each fish at 3 time points: before anesthesia, during anesthesia, and immediately after surgery. Blood gas values and blood lactate concentrations were measured. Fish were monitored for 2 weeks postoperatively. RESULTS-All walleye and koi survived, but 2 perch died. Blood pH significantly decreased in perch from before to during anesthesia, but increased back to preanesthesia baseline values after surgery. Blood Pco(2) decreased significantly in perch from before anesthesia to immediately after surgery, and also from during anesthesia to immediately after surgery, whereas blood Pco(2) decreased significantly in koi from before to during anesthesia. Blood Po(2) increased significantly in both perch and koi from before to during anesthesia, and also in koi from before anesthesia to immediately after surgery. For all 3 species, blood lactate concentrations increased significantly from before anesthesia to immediately after surgery. Blood lactate concentration (mean +/- SD) immediately after surgery for the 8 surviving perch was 6.06 +/- 1.47 mmol/L, which was significantly lower than blood lactate concentrations in the 2 nonsurviving perch (10.58 and 10.72 mmol/L). CONCLUSIONS AND CLINICAL RELEVANCE-High blood lactate concentrations following surgery in fish may be predictive of a poor short-term postoperative survival rate.

  20. Ocean Acidification

    NASA Astrophysics Data System (ADS)

    Iglesias-Rodriguez, Maria Debora

    The oceans play a central role in the maintenance of life on Earth. Oceans provide extensive ecosystems for marine animals and plants covering two-thirds of the Earth's surface, are essential sources of food, economic activity, and biodiversity, and are central to the global biogeochemical cycles. The oceans are the largest reservoir of carbon in the Planet, and absorb approximately one-third of the carbon emissions that are released to the Earth's atmosphere as a result of human activities. Since the beginning of industrialization, humans have been responsible for the increase in one greenhouse gas, carbon dioxide (CO2), from approximately 280 parts per million (ppm) at the end of the nineteenth century to the current levels of 390ppm. As well as affecting the surface ocean pH, and the organisms living at the ocean surface, these increases in CO2 are causing global mean surface temperatures to rise.

  1. Standardized Interpretation of Chest Radiographs in Cases of Pediatric Pneumonia From the PERCH Study

    PubMed Central

    Deloria Knoll, Maria; Barger-Kamate, Breanna; de Campo, John; de Campo, Margaret; Diallo, Mahamadou; Ebruke, Bernard E.; Feikin, Daniel R.; Gleeson, Fergus; Gong, Wenfeng; Hammitt, Laura L.; Izadnegahdar, Rasa; Kruatrachue, Anchalee; Madhi, Shabir A.; Manduku, Veronica; Matin, Fariha Bushra; Mahomed, Nasreen; Moore, David P.; Mwenechanya, Musaku; Nahar, Kamrun; Oluwalana, Claire; Ominde, Micah Silaba; Prosperi, Christine; Sande, Joyce; Suntarattiwong, Piyarat; O’Brien, Katherine L.

    2017-01-01

    Abstract Background. Chest radiographs (CXRs) are a valuable diagnostic tool in epidemiologic studies of pneumonia. The World Health Organization (WHO) methodology for the interpretation of pediatric CXRs has not been evaluated beyond its intended application as an endpoint measure for bacterial vaccine trials. Methods. The Pneumonia Etiology Research for Child Health (PERCH) study enrolled children aged 1–59 months hospitalized with WHO-defined severe and very severe pneumonia from 7 low- and middle-income countries. An interpretation process categorized each CXR into 1 of 5 conclusions: consolidation, other infiltrate, both consolidation and other infiltrate, normal, or uninterpretable. Two members of a 14-person reading panel, who had undertaken training and standardization in CXR interpretation, interpreted each CXR. Two members of an arbitration panel provided additional independent reviews of CXRs with discordant interpretations at the primary reading, blinded to previous reports. Further discordance was resolved with consensus discussion. Results. A total of 4172 CXRs were obtained from 4232 cases. Observed agreement for detecting consolidation (with or without other infiltrate) between primary readers was 78% (κ = 0.50) and between arbitrators was 84% (κ = 0.61); agreement for primary readers and arbitrators across 5 conclusion categories was 43.5% (κ = 0.25) and 48.5% (κ = 0.32), respectively. Disagreement was most frequent between conclusions of other infiltrate and normal for both the reading panel and the arbitration panel (32% and 30% of discordant CXRs, respectively). Conclusions. Agreement was similar to that of previous evaluations using the WHO methodology for detecting consolidation, but poor for other infiltrates despite attempts at a rigorous standardization process. PMID:28575359

  2. Plasma osmolality and oxygen consumption of perch Perca fluviatilis in response to different salinities and temperatures.

    PubMed

    Christensen, E A F; Svendsen, M B S; Steffensen, J F

    2017-03-01

    The present study determined the blood plasma osmolality and oxygen consumption of the perch Perca fluviatilis at different salinities (0, 10 and 15) and temperatures (5, 10 and 20° C). Blood plasma osmolality increased with salinity at all temperatures. Standard metabolic rate (SMR) increased with salinity at 10 and 20° C. Maximum metabolic rate (MMR) and aerobic scope was lowest at salinity of 15 at 5° C, yet at 20° C, they were lowest at a salinity of 0. A cost of osmoregulation (SMR at a salinity of 0 and 15 compared with SMR at a salinity of 10) could only be detected at a salinity of 15 at 20° C, where it was 28%. The results show that P. fluviatilis have capacity to osmoregulate in hyper-osmotic environments. This contradicts previous studies and indicates intraspecific variability in osmoregulatory capabilities among P. fluviatilis populations or habitat origins. An apparent cost of osmoregulation (28%) at a salinity of 15 at 20° C indicates that the cost of osmoregulation in P. fluviatilis increases with temperature under hyperosmotic conditions and a power analysis showed that the cost of osmoregulation could be lower than 12·5% under other environmental conditions. The effect of salinity on MMR is possibly due to a reduction in gill permeability, initiated to reduce osmotic stress. An interaction between salinity and temperature on aerobic scope shows that high salinity habitats are energetically beneficial during warm periods (summer), whereas low salinity habitats are energetically beneficial during cold periods (winter). It is suggested, therefore, that the seasonal migrations of P. fluviatilis between brackish and fresh water is to select an environment that is optimal for metabolism and aerobic scope.

  3. Cyclic spattering, seismic tremor, and surface fluctuation within a perched lava channel, Kīlauea Volcano

    USGS Publications Warehouse

    Patrick, M.R.; Orr, T.; Wilson, D.; Dow, D.; Freeman, R.

    2011-01-01

    In late 2007, a perched lava channel, built up to 45 m above the preexisting surface, developed during the ongoing eruption near Pu‘u ‘Ō‘ō cone on Kīlauea Volcano’s east rift zone. The lava channel was segmented into four pools extending over a total of 1.4 km. From late October to mid-December, a cyclic behavior, consisting of steady lava level rise terminated by vigorous spattering and an abrupt drop in lava level, was commonly observed in pool 1. We use geologic observations, video, time-lapse camera images, and seismicity to characterize and understand this cyclic behavior. Spattering episodes occurred at intervals of 40–100 min during peak activity and involved small (5–10-m-high) fountains limited to the margins of the pool. Most spattering episodes had fountains which migrated downchannel. Each spattering episode was associated with a rapid lava level drop of about 1 m, which was concurrent with a conspicuous cigar-shaped tremor burst with peak frequencies of 4–5 Hz. We interpret this cyclic behavior to be gas pistoning, and this is the first documented instance of gas pistoning in lava well away from the deeper conduit. Our observations and data indicate that the gas pistoning was driven by gas accumulation beneath the visco-elastic component of the surface crust, contrary to other studies which attribute similar behavior to the periodic rise of gas slugs. The gas piston events typically had a gas mass of about 2,500 kg (similar to the explosions at Stromboli), with gas accumulation and release rates of about 1.1 and 5.7 kg s−1, respectively. The time-averaged gas output rate of the gas pistoning events accounted for about 1–2% of the total gas output rate of the east rift zone eruption.

  4. Adding Perches for Cross-Pollination Ensures the Reproduction of a Self-Incompatible Orchid

    PubMed Central

    Li, Li-Qiang; Rao, Wen-Hui; Zhang, Yu-Ting; Tang, Guang-Da; Huang, Lai-Qiang

    2013-01-01

    Background Outcrossing is known to carry genetic advantages in comparison with inbreeding. In many cases, flowering plants develop a self-incompatibility mechanism, along with a floral component adaptation mechanism, to avoid self-pollination and to promote outbreeding. Orchids commonly have a lip in their flower that functions as the a visiting plate for insect pollinators. Aside from the lip, however, many species (including Coelogyne rigida) have sheaths around the axis of inflorescence. The function of these sheaths remains unknown, and has long been a puzzle to researchers. Methodology/Principal Findings We investigated the function of these sheaths in relation to the lip and the pollinators, as well as their role in the modes of pollination and reproduction of Coelogyne rigida in 30 flowering populations of orchids in the limestone area of Southeast Yunnan, China. We found that self-incompatible C. rigida developed specialized bird perches around the basal axis of inflorescence to attract sunbirds and to complement their behavioral tendency to change foraging locations frequently. This self-incompatibility mechanism operates separately from the floral component adaptation mechanism. This mechanism thus prevents bees from repeatedly visiting the floral lip of the same plant which, in turn, results in autogamy. In this way, instead of preventing autogamy, C. rigida responds to these negative effects through a highly efficient cross-pollination method that successfully transfers pollen to different plants. Conclusions The proposed method ensures reproductive success, while offsetting the infertile self-pollination by insects, thereby reducing mating costs and addressing the lack of cross-pollination. The adaptation provides a novel and striking example of structural adaptation that promotes cross-pollination in angiosperms. PMID:23308277

  5. Flow cytometric method for measuring chromatin fragmentation in fixed sperm from yellow perch (Perca flavescens).

    PubMed

    Jenkins, J A; Draugelis-Dale, R O; Pinkney, A E; Iwanowicz, L R; Blazer, V S

    2015-03-15

    Declining harvests of yellow perch, Perca flavescens, in urbanized watersheds of Chesapeake Bay have prompted investigations of their reproductive fitness. The purpose of this study was to establish a flow cytometric technique for DNA analysis of fixed samples sent from the field to provide reliable gamete quality measurements. Similar to the sperm chromatin structure assay, measures were made on the susceptibility of nuclear DNA to acid-induced denaturation, but used fixed rather than live or thawed cells. Nuclei were best exposed to the acid treatment for 1 minute at 37 °C followed by the addition of cold (4 °C) propidium iodide staining solution before flow cytometry. The rationale for protocol development is presented graphically through cytograms. Field results collected in 2008 and 2009 revealed DNA fragmentation up to 14.5%. In 2008, DNA fragmentation from the more urbanized watersheds was significantly greater than from reference sites (P = 0.026) and in 2009, higher percentages of haploid testicular cells were noted from the less urbanized watersheds (P = 0.032) indicating better reproductive condition at sites with less urbanization. For both years, total and progressive live sperm motilities by computer-assisted sperm motion analysis ranged from 19.1% to 76.5%, being significantly higher at the less urbanized sites (P < 0.05). This flow cytometric method takes advantage of the propensity of fragmented DNA to be denatured under standard conditions, or 1 minute at 37 °C with 10% buffered formalin-fixed cells. The study of fixed sperm makes possible the restrospective investigation of germplasm fragmentation, spermatogenic ploidy patterns, and chromatin compaction levels from samples translocated over distance and time. The protocol provides an approach that can be modified for other species across taxa.

  6. Flow cytometric method for measuring chromatin fragmentation in fixed sperm from yellow perch (Perca flavescens)

    USGS Publications Warehouse

    Jenkins, Jill A.; Draugelis-Dale, Rassa O.; Pinkney, Alfred E.; Iwanowicz, Luke R.; Blazer, Vicki

    2015-01-01

    Declining harvests of yellow perch, Perca flavescens, in urbanized watersheds of Chesapeake Bay have prompted investigations of their reproductive fitness. The purpose of this study was to establish a flow cytometric technique for DNA analysis of fixed samples sent from the field to provide reliable gamete quality measurements. Similar to the sperm chromatin structure assay, measures were made on the susceptibility of nuclear DNA to acid-induced denaturation, but used fixed rather than live or thawed cells. Nuclei were best exposed to the acid treatment for 1 minute at 37 °C followed by the addition of cold (4 °C) propidium iodide staining solution before flow cytometry. The rationale for protocol development is presented graphically through cytograms. Field results collected in 2008 and 2009 revealed DNA fragmentation up to 14.5%. In 2008, DNA fragmentation from the more urbanized watersheds was significantly greater than from reference sites (P = 0.026) and in 2009, higher percentages of haploid testicular cells were noted from the less urbanized watersheds (P = 0.032) indicating better reproductive condition at sites with less urbanization. For both years, total and progressive live sperm motilities by computer-assisted sperm motion analysis ranged from 19.1% to 76.5%, being significantly higher at the less urbanized sites (P < 0.05). This flow cytometric method takes advantage of the propensity of fragmented DNA to be denatured under standard conditions, or 1 minute at 37 °C with 10% buffered formalin–fixed cells. The study of fixed sperm makes possible the restrospective investigation of germplasm fragmentation, spermatogenic ploidy patterns, and chromatin compaction levels from samples translocated over distance and time. The protocol provides an approach that can be modified for other species across taxa.

  7. Establishment and interspecific associations in two species of Ichthyocotylurus (Trematoda) parasites in perch (Perca fluviatilis)

    PubMed Central

    2011-01-01

    Background Co-infections of multiple parasite species in hosts may lead to interspecific associations and subsequently shape the structure of a parasite community. However, few studies have focused on these associations in highly abundant parasite species or, in particular, investigated how the associations develop with time in hosts exposed to co-infecting parasite species for the first time. We investigated metacercarial establishment and interspecific associations in the trematodes Ichthyocotylurus variegatus and I. pileatus co-infecting three age cohorts of young perch (Perca fluviatilis). Results We found that the timing of transmission of the two Ichthyocotylurus species was very similar, but they showed differences in metacercarial development essentially so that the metacercariae of I. pileatus became encapsulated faster. Correlations between the abundances of the species were significantly positive after the first summer of host life and also within the main site of infection, the swim bladder. High or low abundances of both parasite species were also more frequent in the same host individuals than expected by chance, independently of host age or size. However, the highest abundances of the species were nevertheless observed in different host individuals and this pattern was consistent in all age cohorts. Conclusions The results suggest similar temporal patterns of transmission, non-random establishment, and facilitative rather than competitive associations between the parasite species independently of the age of the infracommunities. However, we suggest that spatial differences in exposure are most likely responsible for the segregation of the parasite species observed in the few most heavily infected hosts. Regardless of the underlying mechanism, the result suggests that between-species associations should be interpreted with caution along with detailed examination of the parasite distribution among host individuals. PMID:21599910

  8. Concentrations of 17 elements in the zebra mussel (Dreissena polymorpha), in different tissues of perch (Perca fluviatilis), and in perch intestinal parasites (Acanthocephalus lucii) from the subalpine lake Mondsee, Austria

    SciTech Connect

    Sures, B.; Steiner, W.; Rydlo, M.; Taraschewski, H.

    1999-11-01

    Concentrations of the elements Al, Ag, Ba, ca, Cd, Co, Cr, cu, Fe, Ga, Mg, Mn, Ni, Pb, Sr, Tl, and Zn were analyzed by inductively coupled plasma mass spectrometry in the acanthocephalan Acanthocephalus lucii (Mueller); in its host, Perca fluviatilis (L.), and in the soft tissue of the zebra mussel, Dreissena polymorpha (Pallas). All animals were collected from the same sampling site in a subalpine lake, Mondsee, in Austria. Most of the elements were found at significantly higher concentrations in the acanthocephalan than in different tissues (muscle, liver, and intestinal wall) of its perch host. Only Co was concentrated in the liver of perch to a level that was significantly higher than that found in the parasite. Most of the analyzed elements were also present at significantly higher concentrations in A. lucii than in D. polymorpha. Barium and Cr were the only elements recorded at higher concentrations in the mussel compared with the acanthocephalan. Thus, when comparing the accumulation of elements, the acanthocephalans appear to be even more suitable than the zebra mussels in terms of their use in the detection of metal contamination within aquatic biotopes. Spearman correlation analysis revealed that the concentrations of several elements within the parasites decreased with increasing infrapopulation. Furthermore, the levels of some elements in the perch liver were negatively correlated with the weight of A. lucii in the intestine. Thus, it emerged that not only is there competition for elements between acanthocephalans inside the gut but there is also competition for these elements between the host and the parasites. The elevated element concentrations demonstrated here in the parasitic worm A. lucii provide support for further investigations of these common helminthes and of their accumulation properties.

  9. Development of an enzyme-linked immunosorbent assay for detection of chicken osteocalcin and its use in evaluation of perch effects on bone remodeling in caged White Leghorns.

    PubMed

    Jiang, S; Cheng, H W; Hester, P Y; Hou, J-F

    2013-08-01

    Osteocalcin (OC) is a sensitive biochemical marker for evaluating bone turnover in mammals. The role of avian OC is less clear because of the need for a chicken assay. Our objectives were to develop an assay using indirect competitive ELISA for detecting chicken serum OC and use the assay to examine the effects of perches on bone remodeling in caged hens. Anti-chicken OC polyclonal antibody was produced by immunization of rabbits with a recombinant OC from Escherichia coli. Chicken OC extracted from bone was used as a coated protein, and purified chicken OC was used for calibration. The limit of detection of the developed OC ELISA was 0.13 ng/mL. The intra- and interassay CV were <7 and <12%, respectively. The sensitivity of the developed OC ELISA was compared with a commercial Rat-Mid OC ELISA in laying hens housed in conventional cages with or without perches. Serum samples were collected from 71-wk-old White Leghorn hens subjected to 4 treatments. Treatment 1 was control chickens that never had access to perches during their life cycle. Treatment 2 chickens had perches during the pullet phase (0 to 16.9 wk of age), whereas treatment 3 chickens had perches only during the egg-laying phase of the life cycle (17 to 71 wk of age). Treatment 4 chickens always had access to perches (0 to 71 wk of age). Correlation between the 2 assays was 0.62 (P < 0.0001). Levels of serum OC using the developed chicken ELISA were higher than that detected using the Rat-Mid ELISA (P < 0.0001). Results from the chicken ELISA assay showed that hens with perch access had higher concentrations of serum OC than hens without perches during egg laying (P = 0.04). Pullet access to perches did not affect serum OC levels in 71-wk-old hens (P = 0.15). In conclusion, a chicken OC ELISA has been validated that is sensitive and accurate with adequate discriminatory power for measuring bone remodeling in chickens.

  10. Effect of bioconcentration and trophic transfer on realized exposure to oxazepam in 2 predators, the dragonfly larvae (Aeshna grandis) and the Eurasian perch (Perca fluviatilis).

    PubMed

    Heynen, Martina; Fick, Jerker; Jonsson, Micael; Klaminder, Jonatan; Brodin, Tomas

    2016-04-01

    Psychoactive substances are used worldwide and constitute one of the most common groups of pharmaceutical contaminants in surface waters. Although these pharmaceuticals are designed to be efficiently eliminated from the human body, very little is known about their trophic-transfer potential in aquatic wildlife. Therefore, the goal of the present study was to quantify and compare uptake of an anxiolytic (oxazepam) from water (bioconcentration) and via the consumption of contaminated diet (trophic transfer) in 2 common freshwater predators: Eurasian perch (Perca fluviatilis) and the dragonfly larvae Aeshna grandis. Bioconcentration and trophic transfer of oxazepam were found in both predator species. However, higher bioconcentrations were observed for perch (bioconcentration factor [BCF], 3.7) than for dragonfly larvae (BCF, 0.5). Perch also retained more oxazepam from consumed prey (41%) than dragonfly larvae (10%), whereas the relative contribution via prey consumption was 14% and 42% for perch and dragonflies, respectively. In addition, bioconcentration was negatively correlated with perch weight, indicating that exposure levels in natural contaminated environments differ between individuals of different size or between different developmental stages. Hence, trophic transfer of pharmaceuticals may indeed occur, and estimates of environmental exposures that do not consider intake via food or size-dependent bioconcentration may therefore lead to wrongful estimations of realized exposure levels in natural contaminated ecosystems.

  11. Investigating bomb radiocarbon transport in the southern Pacific Ocean with otolith radiocarbon

    NASA Astrophysics Data System (ADS)

    Grammer, G. L.; Fallon, S. J.; Izzo, C.; Wood, R.; Gillanders, B. M.

    2015-08-01

    To explore the transport of carbon into water masses from the surface ocean to depths of ∼ 1000 m in the southwest Pacific Ocean, we generated time series of radiocarbon (Δ14C) from fish otoliths. Otoliths (carbonate earstones) from long-lived fish provide an indirect method to examine the "bomb pulse" of radiocarbon that originated in the 1950s and 1960s, allowing identification of changes to distributions of 14C that has entered and mixed within the ocean. We micro-sampled ocean perch (Helicolenus barathri) otoliths, collected at ∼ 400- 500 m in the Tasman Sea, to obtain measurements of Δ14C for those depths. We compared our ocean perch Δ14C series to published otolith-based marine surface water Δ14C values (Australasian snapper (Chrysophrys auratus) and nannygai (Centroberyx affinis)) and to published deep-water values (800-1000 m; orange roughy (Hoplostethus atlanticus)) from the southwest Pacific to establish a mid-water Δ14C series. The otolith bomb 14C results from these different depths were consistent with previous water mass results in the upper 1500 m of the southwest Pacific Ocean (e.g. World Ocean Circulation Experiment and Geochemical Ocean Sections Study). A comparison between the initial Δ14C bomb pulse rise at 400-500 m suggested a ventilation lag of 5 to 10 yr, whereas a comparison of the surface and depths of 800-1000 m detailed a 10 to 20 yr lag in the time history of radiocarbon invasion at this depth. Pre-bomb reservoir ages derived from otolith 14C located in Tasman Sea thermocline waters were ∼ 530 yr, while reservoir ages estimated for Tasman Antarctic intermediate water were ∼ 730 yr.

  12. Bone-Remodeling Transcript Levels Are Independent of Perching in End-of-Lay White Leghorn Chickens

    PubMed Central

    Dale, Maurice D.; Mortimer, Erin M.; Kolli, Santharam; Achramowicz, Erik; Borchert, Glenn; Juliano, Steven A.; Halkyard, Scott; Sietz, Nick; Gatto, Craig; Hester, Patricia Y.; Rubin, David A.

    2015-01-01

    Osteoporosis is a bone disease that commonly results in a 30% incidence of fracture in hens used to produce eggs for human consumption. One of the causes of osteoporosis is the lack of mechanical strain placed on weight-bearing bones. In conventionally-caged hens, there is inadequate space for chickens to exercise and induce mechanical strain on their bones. One approach is to encourage mechanical stress on bones by the addition of perches to conventional cages. Our study focuses on the molecular mechanism of bone remodeling in end-of-lay hens (71 weeks) with access to perches. We examined bone-specific transcripts that are actively involved during development and remodeling. Using real-time quantitative PCR, we examined seven transcripts (COL2A1 (collagen, type II, alpha 1), RANKL (receptor activator of nuclear factor kappa-B ligand), OPG (osteoprotegerin), PTHLH (PTH-like hormone), PTH1R (PTH/PTHLH type-1 receptor), PTH3R (PTH/PTHLH type-3 receptor), and SOX9 (Sry-related high mobility group box)) in phalange, tibia and femur. Our results indicate that the only significant effect was a difference among bones for COL2A1 (femur > phalange). Therefore, we conclude that access to a perch did not alter transcript expression. Furthermore, because hens have been used as a model for human bone metabolism and osteoporosis, the results indicate that bone remodeling due to mechanical loading in chickens may be a product of different pathways than those involved in the mammalian model. PMID:25625518

  13. Elevated temperature and acclimation time affect metabolic performance in the heavily exploited Nile perch of Lake Victoria.

    PubMed

    Nyboer, Elizabeth A; Chapman, Lauren J

    2017-08-18

    Increasing water temperatures due to anthropogenic climate change are predicted to negatively impact the aerobic metabolic performance of aquatic ectotherms. Specifically, it has been hypothesized that thermal increases result in reductions in aerobic scope (AS), which lead to decreases in energy available for essential fitness and performance functions. Consequences of warming are anticipated to be especially severe for warm-adapted tropical species as they are thought to have narrow thermal windows and limited plasticity for coping with elevated temperatures. In this study we test how predicted warming may affect the aerobic performance of Nile perch (Lates niloticus), a commercially-harvested fish species in the Lake Victoria basin of East Africa. We measured critical thermal maxima (CTmax) and key metabolic variables such as AS and excess post-exercise oxygen consumption (EPOC) across a range of temperatures, and compared responses between acute (3-day) exposures and 3-week acclimations. CTmax increased with acclimation temperature, however 3-week acclimated fish had higher overall CTmax than acutely-exposed individuals. Nile perch also showed the capacity to increase or maintain high AS even at temperatures well beyond their current range, however acclimated Nile perch had lower AS compared to acutely-exposed fish. These changes were accompanied by lower EPOC, suggesting that drops in AS may reflect improved energy utilization after acclimation, a finding that is supported by improvements in growth at high temperatures over the acclimation period. Overall, the results challenge predictions that tropical species have limited thermal plasticity, and that high temperatures will be detrimental due to limitations in AS. © 2017. Published by The Company of Biologists Ltd.

  14. Parasite communities of European perch, Perca fluviatilis L. (Actinopterygii: Perciformes: Percidae) from Lake Łebsko (Central Coast, Poland).

    PubMed

    Morozińska-Gogol, Jolanta

    2013-01-01

    Communities of parasites of European perch from lake Łebsko were studied and compared with similar communities from the Polish coastal zone. Parasites comprised 18 autogenic and 5 allogenic species. Most individual parasites belonged to allogenic species and were in larval stages. The majority of specimens were eye parasites with Tylodelphys clavata as the eudominant species. The dominant species, Acanthocephalus lucii, belongs to the intestine parasite community. Three marine species were found: Bothriocephalus scorpii, Hysterothylacium aduncum and Echinorchynhus gadi. The results indicate that the parasite fauna consists mostly of freshwater species, common in various types of European waters, while marine species were rarely observed.

  15. Ocean Acidification

    EPA Pesticide Factsheets

    Ocean and coastal acidification is an emerging issue caused by increasing amounts of carbon dioxide being absorbed by seawater. Changing seawater chemistry impacts marine life, ecosystem services, and humans. Learn what EPA is doing and what you can do.

  16. Ocean dumping

    SciTech Connect

    Not Available

    1982-01-01

    The regulation of the dumping of materials into the ocean is reviewed. Criteria to be applied in reviewing and evaluating permit applications for the transportation and dumping of materials into the ocean are established. A definition of monitoring of dumping sites, the assessment of fees to cover permit processing costs, and a moratorium is placed on the issuance of permits for the disposal of radioactive waste are included.

  17. Field-Derived Hydraulic Properties for Perched-Water Aquifer Wells 299-E33-350 and 299-E33-351, Hanford Site B-Complex Area

    SciTech Connect

    Newcomer, Darrell R.

    2014-07-01

    During February and March 2014, Pacific Northwest National Laboratory conducted hydraulic (slug) tests at 200-DV-1 Operable Unit wells 299-E33-350 (C8914) and 299-E33-351 (C8915) as part of B-Complex Area Perched-Water characterization activities at the Hanford Site 200-East Area. During the construction/completion phase of each well, two overlapping depth intervals were tested within the unconfined perched-water aquifer contained in the silty-sand subunit of the Cold Creek Unit. The purpose of the slug-test characterization was to provide estimates of transmissivity and hydraulic conductivity for the perched-water aquifer at these selected well locations.

  18. [Genetic study of pike perch Sander lucioperca (Linnaeus, 1758) and bersh Sander volgensis (Gmelin, 1789) from the fishery water-bodies of Kazakhstan].

    PubMed

    Barmintseva, A E; Shalgimbayeva, G M; Koishibayeva, S K; Sarbakanova, S T; Asylbekova, S Z; Isbekov, K B; Mugue, N S

    2014-07-01

    The genetic polymorphism of the pike perch Sander lucioperca, sampled on the territory of the Republic of Kazakhstan (Lake Balkhash, Urals River, Syrdarya River and Shardara water reservoir, North Aral Sea) and in the Volga River, and the bersh Sandler volgensis (Lake Balkhash, Volga River) populations was examined at six microsatellite loci and the mitochondrial DNA cytochirome b gene. All examined loci were successfully amplified in both species and produced quite different allele profiles, whichallows them to be used for accurate species identification of pike perch and bersh. At the same time, neither nuclear nor mitochondrial markers revealed statistically significant differentiation betweenthe examined pike perch samples, excluding some isolation of the population from Volga River.

  19. Evaluating the spatial variation of total mercury in young-of-year yellow perch (Perca flavescens), surface water and upland soil for watershed-lake systems within the southern Boreal Shield

    Treesearch

    Mark C. Gabriel; Randy Kolka; Trent Wickman; Ed Nater; Laurel. Woodruff

    2009-01-01

    The primary objective of this research is to investigate relationships between mercury in upland soil, lake water and fish tissue and explore the cause for the observed spatial variation of THg in age one yellow perch (Perca flavescens) for ten lakes within the Superior National Forest. Spatial relationships between yellow perch THg tissue...

  20. Metabolic and thyroidal response in air-breathing perch (Anabas testudineus) to water-borne kerosene.

    PubMed

    Peter, Valsa S; Joshua, Elizabeth K; Wendelaar Bonga, Sjoerd E; Peter, M C Subhash

    2007-01-01

    To address the physiological compensatory adaptations in air-breathing fish to a toxicant, we studied the metabolite pattern, serum and liver enzymes and thyroidal response in a tropical air-breathing perch, Anabas testudineus (kept at 30 degrees C in a 12-h L:D cycle) after exposing the fish for 48h to the water-soluble fraction of kerosene. The concentrations of serum glucose (P <0.05), triglycerides (P <0.01) and liver total protein (P <0.05) were significantly increased in kerosene-exposed fish. The serum urea level, however, remained unaffected. A significant (P <0.05) increase in liver RNA occurred without changing the liver DNA concentration. Kerosene exposure decreased the level of aspartate aminotransferase activities in serum (P <0.001) and liver (P <0.05) but it increased (P <0.05) the liver alanine aminotransferase activity without changing its activity in serum. The levels of serum (P <0.01) and liver (P <0.001) lactate dehydrogenase activity were declined and the serum (P <0.05) and liver (P <0.05) alkaline phosphatase activity levels were elevated in kerosene-treated fish. The nominated levels (3.33-6.66ml/L) of kerosene significantly (P <0.01) elevated the thyroxine (T(4)) titre, and reduced (P <0.05) the triiodothyronine (T(3)) titre. The fish pretreated with either T(3) or T(4) and exposed to kerosene had a metabolic and thyroidal response that differed from that in control fish treated with kerosene: no rise in serum glucose was observed, nor in triglycerides, total protein and RNA in the liver, whereas declined levels of T(4) and T(3) were observed. The upregulation of the thyroid along with the marked metabolite changes point to a positive involvement of thyroid in energy metabolism during kerosene exposure. This is consistent with the hypothesis that the fish thyroid responds to the action of petroleum products and influences the metabolic homeostasis of this air-breathing fish.

  1. Hanging out at the airport: Unusual upside-down perching behavior by Eurasian Jackdaws (Corvus monedula) in a human-dominated environment

    USGS Publications Warehouse

    Katzner, Todd E.

    2016-01-01

    Animals occupying human-dominated environments show the capacity for behavioral flexibility. Corvids are among the most intelligent synanthropic bird species. During a layover at Schipol Airport in Amsterdam, Netherlands, I photographically documented Eurasian Jackdaws (Corvus monedula) perching upside down from a building cornice. In contrast to other reports of hanging birds, these jackdaws did not forage or play while upside down and appeared to use the perching spot to observe their surroundings. Although Corvids and Psittacines are known to hang upside down, especially in captive situations, such behaviors are rarely documented in the wild, and never before in association with human-built structures.

  2. Perches and elevated platforms in commercial broiler farms: use and effect on walking ability, incidence of tibial dyschondroplasia and bone mineral content.

    PubMed

    Kaukonen, E; Norring, M; Valros, A

    2017-05-01

    Modern fast-growing broilers spend excessive periods resting and their activity further decreases with age. Inactivity has been suggested to increase impaired gait and the incidence of leg disorders. Tibial dyschondroplasia (TD) is a common leg pathology in broilers. A more complex environment might facilitate more activity and improve leg health. Perches or elevated platforms bring variety to broilers' environment and could motivate more locomotion. This study examined the impact of perches and elevated platforms on walking ability, the occurrence of TD and level of bone ash and mineral contents. The investigation was performed on four commercial broiler farms throughout six consecutive batches with platforms and four to five with perches. On each farm at least two separate houses were included, enabling the comparison of furnished flocks to control flocks during each batch. Plastic slats with ramp access elevated by 30 cm or wooden perches of 10 and 30 cm height were offered in the furnished house. Farmers recorded the platform and perch usage twice a week with a five-point scale. Gait was scored before slaughter on a six-point scale according to the Welfare Quality® assessment protocol for poultry. The severity of TD was determined using a four-point scale on farm from all birds gait scored as 3 and at slaughter from 200 birds/flock. Farmers estimated 50% to 100% of the platforms to be occupied in all flocks throughout the entire growing period. Only single birds were perching, thus perch structures were constantly evaluated to be empty. Due to the low use, the perch-equipped houses were excluded when analysing bone content, walking ability and TD. On average, 30% of the tested birds exhibited gait score ⩾3. Younger scoring age resulted in a lower mean gait score and a lower percentage of scores 3 and 4 to 5. Overall, 2.3% of the birds examined at slaughter and 3.5% of the birds with gait score 3 were affected by TD. Leg health was better in birds with access

  3. The feasibility of thermal inertia mapping for detection of perched water tables in semi-arid irrigated lands

    NASA Technical Reports Server (NTRS)

    Ezra, C. E.; Estes, J. E.; Bonn, F.

    1982-01-01

    The thermal inertia mapping remote sensing technique is evaluated as a potential method for delineating areas of shallow perched water tables and related salinization problems on a regional basis. This method for detecting shallow water tables is based on the existence of significant differences in soil thermal properties between wet and dry soil profiles. Ground observations were conducted at two different test sites in California along the flight line, with one site located in a perched water table area and the other site in a well drained area. Measurements were taken hourly during a four day period (two days before and two days after the flight) for variables such as radiometric, meteorologic, soil moisture and temperature profiles, and surface characteristics. Results indicate that it is not feasible using present apparent thermal inertia remote sensing techniques to reliably delineate regional patterns of very shallow water tables due to the complex environmental system. However, some features within specific fields which may be directly related to the local presence of shallow water tables, such as differences in evaporative cooling due to soil moisture effects between and within fields, can be detected using the thermal inertia technique.

  4. Effect of pH on Structural Changes in Perch Hemoglobin that Can Alter Redox Stability and Heme Affinity

    SciTech Connect

    Richards, Mark P.; Aranda, IV, Roman; He, Cai; Phillips, Jr., George N.

    2010-01-07

    pH can be manipulated to alter the oxidative stability of fish-based foods during storage. X-ray diffraction was used to investigate the ability of reduced pH to cause structural changes in fish hemoglobins that lead to enhanced oxidative degradation. Decreasing pH from 8.0 to 6.3 and 5.7 created a large channel for solvent entry into the heme crevice of perch hemoglobin beta chains. The proton-induced opening of this channel occurred between site CD3 and the heme-6-propionate. Solvent entry into the heme crevice can enhance metHb formation and hemin loss, processes that accelerate lipid oxidation. Reduced pH also decreased the distance between Ile at E11 in one of the alpha chains and the ligand above the heme iron atom. This sterically displaces O{sub 2} and protonated O{sub 2} which increases metHb formation. These studies demonstrate that pH reduction causes structural changes in perch hemoglobin which increase oxidative degradation of the heme pigment.

  5. Transcriptional response of yellow perch to changes in ambient metal concentrations-A reciprocal field transplantation experiment.

    PubMed

    Bougas, Bérénice; Normandeau, Eric; Grasset, Julie; Defo, Michel A; Campbell, Peter G C; Couture, Patrice; Bernatchez, Louis

    2016-04-01

    Recent local adaptation to pollution has been evidenced in several organisms inhabiting environments heavily contaminated by metals. Nevertheless, the molecular mechanisms underlying adaptation to high metal concentrations are poorly understood, especially in fishes. Yellow perch (Perca flavescens) populations from lakes in the mining area of Rouyn-Noranda (QC, Canada) have been faced with metal contamination for about 90 years. Here, we examine gene transcription patterns of fish reciprocally transplanted between a reference and a metal-contaminated lake and also fish caged in their native lake. After four weeks, 111 genes were differentially transcribed in metal-naïve fish transferred to the metal-contaminated lake, revealing a plastic response to metal exposure. Genes involved in the citric cycle and beta-oxidation pathways were under-transcribed, suggesting a potential strategy to mitigate the effects of metal stress by reducing energy turnover. However, metal-contaminated fish transplanted to the reference lake did not show any transcriptomic response, indicating a reduced plastic response capability to sudden reduction in metal concentrations. Moreover, the transcription of other genes, especially ones involved in energy metabolism, was affected by caging. Overall, our results highlight environmental stress response mechanisms in yellow perch at the transcriptomic level and support a rapid adaptive response to metal exposure through genetic assimilation.

  6. Chemosensory mediated behaviors and gene transcription profiles in wild yellow perch (Perca flavescens) from metal contaminated lakes.

    PubMed

    Azizishirazi, Ali; Dew, William A; Bougas, Berenice; Dashtban, Mehdi; Bernatchez, Louis; Pyle, Greg G

    2014-08-01

    The olfactory system of fish is sensitive to the toxic effects of low concentrations of contaminants. To investigate the effects of long-term metal exposure on olfaction in wild yellow perch (Perca flavescens), fish from one clean (Geneva Lake) and two metal-contaminated lakes (Ramsey and Hannah lakes) were collected in and around the metal-mining district of Sudbury, ON. Two different techniques were used to measure the effects of exposure to environmental contamination: (i) behavioral responses were recorded in response to conspecific skin extract and (ii) gene transcription differences in olfactory rosettes were characterized using a novel, 1000-candidate gene yellow perch microarray. Behavioral assays performed on fish from the clean lake demonstrated avoidance of a conspecific skin extract, while fish from metal contaminated lakes showed no avoidance response. A total of 109 out of the 1000 genes were differentially transcribed among the lakes. Most of the differentially transcribed genes were between the two metal contaminated lakes relative to either of the contaminated lakes and the reference lake. No genes were differentially expressed between Geneva Lake (clean) and Hannah Lake (metal contaminated). These results demonstrated that even though the different populations of fish from both Hannah and Ramey lakes were affected at the behavioral level, the impairment of olfaction was not measurable using gene transcriptional changes in olfactory rosettes. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Seasonal and year-to-year variation of mercury concentration in perch (Perca fluviatilis) in boreal lakes.

    PubMed

    Braaten, Hans Fredrik Veiteberg; Fjeld, Eirik; Rognerud, Sigurd; Lund, Espen; Larssen, Thorjørn

    2014-12-01

    The authors examined the seasonal and year-to-year variations of mercury (Hg) concentrations in populations of perch (Perca fluviatilis) from 2 boreal freshwater lakes in southeast Norway. Fish Hg concentrations were determined seasonally (spring, summer, and autumn) over 3 yr (2010, 2011, and 2012) to test the hypothesis that there are substantial changes in fish Hg concentrations during the year (seasonal variation) as well as annually. Concentrations were significantly (p < 0.0001) different in the 2 study lakes, with mean seasonal concentrations varying from 0.24 mg/kg to 0.36 mg/kg and from 0.29 mg/kg to 0.37 mg/kg, respectively. The Hg concentrations of both perch populations showed significant year-to-year (p < 0.0001) and seasonal variation (p < 0.01). The changing fish Hg concentrations were 25% and 28% (2010-2011) and 17% and 0% (2011-2012) in the 2 lakes over the 3 yr, respectively. The results demonstrate how the significant year-to-year increase is, among other variables, related to changes in trophic position, shown through stable nitrogen (δ(15)N) isotope data. The seasonal variation is related to summer growth dilution. The results highlight the clear need for yearly studies of fish Hg concentrations, rather than the 3-yr cycle suggested by current European policy through the Water Framework Directive. The lack of yearly sampling may result in erroneous conclusions regarding fish Hg concentration time trends. © 2014 SETAC.

  8. Arctic Ocean

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.; Zukor, Dorothy J. (Technical Monitor)

    2000-01-01

    The Arctic Ocean is the smallest of the Earth's four major oceans, covering 14x10(exp 6) sq km located entirely within the Arctic Circle (66 deg 33 min N). It is a major player in the climate of the north polar region and has a variable sea ice cover that tends to increase its sensitivity to climate change. Its temperature, salinity, and ice cover have all undergone changes in the past several decades, although it is uncertain whether these predominantly reflect long-term trends, oscillations within the system, or natural variability. Major changes include a warming and expansion of the Atlantic layer, at depths of 200-900 m, a warming of the upper ocean in the Beaufort Sea, a considerable thinning (perhaps as high as 40%) of the sea ice cover, a lesser and uneven retreat of the ice cover (averaging approximately 3% per decade), and a mixed pattern of salinity increases and decreases.

  9. The Ocean.

    ERIC Educational Resources Information Center

    Broecker, Wallace S.

    1983-01-01

    The chemistry of the ocean, whose constituents interact with those of air and land to support life and influence climate, is known to have undergone changes since the last glacial epoch. Changes in dissolved oxygen, calcium ions, phosphate, carbon dioxide, carbonate ions, and bicarbonate ions are discussed. (JN)

  10. Ocean Acidification

    ERIC Educational Resources Information Center

    Ludwig, Claudia; Orellana, Mónica V.; DeVault, Megan; Simon, Zac; Baliga, Nitin

    2015-01-01

    The curriculum module described in this article addresses the global issue of ocean acidification (OA) (Feely 2009; Figure 1). OA is a harmful consequence of excess carbon dioxide (CO[subscript 2]) in the atmosphere and poses a threat to marine life, both algae and animal. This module seeks to teach and help students master the cross-disciplinary…

  11. The Ocean.

    ERIC Educational Resources Information Center

    Broecker, Wallace S.

    1983-01-01

    The chemistry of the ocean, whose constituents interact with those of air and land to support life and influence climate, is known to have undergone changes since the last glacial epoch. Changes in dissolved oxygen, calcium ions, phosphate, carbon dioxide, carbonate ions, and bicarbonate ions are discussed. (JN)

  12. Ocean Acidification

    ERIC Educational Resources Information Center

    Ludwig, Claudia; Orellana, Mónica V.; DeVault, Megan; Simon, Zac; Baliga, Nitin

    2015-01-01

    The curriculum module described in this article addresses the global issue of ocean acidification (OA) (Feely 2009; Figure 1). OA is a harmful consequence of excess carbon dioxide (CO[subscript 2]) in the atmosphere and poses a threat to marine life, both algae and animal. This module seeks to teach and help students master the cross-disciplinary…

  13. Ocean nutrients

    NASA Astrophysics Data System (ADS)

    Boyd, Philip W.; Hurd, Catriona L.

    Nutrients provide the chemical life-support system for phytoplankton in the ocean. Together with the carbon fixed during photosynthesis, nutrients provide the other elements, such as N and P, needed to synthesize macromolecules to build cellular constituents such as ribosomes. The makeup of these various biochemicals, such as proteins, pigments, and nucleic acids, together determine the elemental stoichiometry of an individual phytoplankton cell. The stoichiometry of different phytoplankton species or groups will vary depending on the proportions of distinct cellular machinery, such as for growth or resource acquisition, they require for their life strategies. The uptake of nutrients by phytoplankton helps to set the primary productivity, and drives the biological pump, of the global ocean. In the case of nitrogen, the supply of nutrients is categorized as either new or regenerated. The supply of new nitrogen, such as nitrate upwelled from the ocean' interior or biological nitrogen fixation, is equal to the vertical export of particular organic matter from the upper ocean on a timescale of years. Nutrients such as silica can also play a structural role in some phytoplankton groups, such as diatoms, where they are used to synthesize a siliceous frustule that offers some mechanical protection from grazers. In this chapter, we also explore nutrient uptake kinetics, patterns in nutrient distributions in space and time, the biogeochemical cycle of nitrogen, the atmospheric supply of nutrients, departures from the Redfield ratio, and whether nutrient distributions and cycling will be altered in the future

  14. [HELMINTHS OF THE COMMON ROACH (RUTILUS RUTILUS LINNAEUS, 1758) AND THE EUROPEAN PERCH (PERCA FLUVIALITIS LINNAEUS, 1758) IN THE LAKE TERKHIIN TSAGAAN (MONGOLIA)].

    PubMed

    Lebedeva, D I; Mendsaikhan, B; Chantuu, Kh; Jargalmaa, G

    2015-01-01

    The article provides data about helminthes of the common roach and the European perch in the Lake Terkhiin Tsagaan (Mongolia). Six parasite species were found. Data on the occurrence of the trematode species and larvae of Streptocara crassicauda are obtained for the first time. Species composition of Diplostomum spp. metacercariae parasitizing in fish eyes is updated.

  15. Development of yellow perch (Perca flavescens) broodstocks: initial characterization of growth and quality traits following grow-out of different stocks

    USDA-ARS?s Scientific Manuscript database

    Broodstocks of yellow perch (Perca flavescens) were initiated from fertilized gametes obtained from wild fish taken from the Perquimans River (North Carolina), Choptank River (Maryland), Lake Winnebago (Wisconsin), and Lac du Flambeau (Wisconsin). Populations at these sites were chosen based on the ...

  16. A Transient Numerical Simulation of Perched Ground-Water Flow at the Test Reactor Area, Idaho National Engineering and Environmental Laboratory, Idaho, 1952-94

    SciTech Connect

    B. R. Orr

    1999-11-01

    Studies of flow through the unsaturated zone and perched ground-water zones above the Snake River Plain aquifer are part of the overall assessment of ground-water flow and determination of the fate and transport of contaminants in the subsurface at the Idaho National Engineering and Environmental Laboratory (INEEL). These studies include definition of the hydrologic controls on the formation of perched ground-water zones and description of the transport and fate of wastewater constituents as they moved through the unsaturated zone. The definition of hydrologic controls requires stratigraphic correlation of basalt flows and sedimentary interbeds within the saturated zone, analysis of hydraulic properties of unsaturated-zone rocks, numerical modeling of the formation of perched ground-water zones, and batch and column experiments to determine rock-water geochemical processes. This report describes the development of a transient numerical simulation that was used to evaluate a conceptual model of flow through perched ground-water zones beneath wastewater infiltration ponds at the Test Reactor Area (TRA).

  17. Radiographic evaluation of perching-joint angles in cockatiels (Nymphicus hollandicus), Hispaniolan Amazon parrots (Amazona ventralis), and barred owls (Strix varia).

    PubMed

    Bonin, Glen; Lauer, Susanne K; Guzman, David Sanchez-Migallon; Nevarez, Javier; Tully, Thomas N; Hosgood, Giselle; Gaschen, Lorrie

    2009-06-01

    Information on perching-joint angles in birds is limited. Joint immobilization in a physiologic perching angle has the potential to result more often in complete restoration of limb function. We evaluated perching-joint angles in 10 healthy cockatiels (Nymphicus hollandicus), 10 Hispaniolan Amazons (Amazona ventralis), and 9 barred owls (Strix varia) and determined intra- and interobserver variability for goniometric measurements in 2 different radiographic projections. Intra- and interobserver variation was less than 7% for all stifle and intertarsal joint measurements but frequently exceeded 10% for the hip-joint measurements. Hip, stifle, and intertarsal perching angles differed significantly among cockatiels, Hispaniolan Amazon parrots, and barred owls. The accuracy of measurements performed on straight lateral radiographic projections with superimposed limbs was not consistently superior to measurements on oblique projections with a slightly rotated pelvis. Stifle and intertarsal joint angles can be measured on radiographs by different observers with acceptable variability, but intra- and interobserver variability for hip-joint-angle measurements is higher.

  18. Yellow perch larval survival studies and the potential effects of an ash storage facility in the Zekiah Swamp watershed, Wicomico River, Maryland

    SciTech Connect

    Buron, W.H.; Pinkney, A.E.; Gurley, J.

    1990-10-01

    Bioassay studies were conducted to determine if leachate from a coal ash depository was a potential factor in reducing abundance of yellow perch spawning stocks in Zekiah Swamp Run, a tributary of the Wicomico River, Maryland. In situ bioassays conducted in Zekiah Swamp Run in 1989 and 1990 using yellow perch yolk-sac larvae resulted in higher mortality upstream and downstream of the ash storage facility relative to reference stations in both years. Similar high mortality was observed at the upstream unaffected site and the downstream potentially affected site, suggesting that poor larval survival in these locations is a system-wide phenomenon. Analysis of water samples for metals, inorganic monomeric-aluminum, volatile organics, pH and measurements of physical parameters did not identify a specific cause for the high mortality observed. Surveys of the abundance and distribution of yellow perch egg strands during spring 1990 revealed that over 1,500 females spawned in a relatively restricted area in the vicinity of the fall line. In contrast to poor larval survival observed at upstream locations above the fall line, good survival was observed in bioassays conducted at a location below the fall line. Results to date are insufficient to establish the specific factors causing high mortality of larval yellow perch above the fall line. However, the ash storage site does not appear to be a contributing factor at the present time.

  19. From yellow perch to round goby: A review of double-crested cormorant diet and fish consumption at three St. Lawrence River colonies, 1999–2013

    USGS Publications Warehouse

    Johnson, James H.; Farquhar, James F; Klindt, Rodger M; Mazzocchi, Irene; Mathers, Alastair

    2015-01-01

    The number of double-crested cormorants (Phalacrocorax auritus) in the upper St. Lawrence River has increased markedly since the early 1990s. In 1999, a binational study was initiated to examine the annual diet composition and fish consumption of cormorants at colonies in the upper river. Since 1999, 14,032 cormorant pellets, collected from May through September each year, have been examined from St. Lawrence River colonies to estimate fish consumption and determine temporal and spatial variation in diet. Seasonal variation in diet composition within a colony was low. Prior to 2006 yellow perch was the primary fish consumed by cormorants in the upper St. Lawrence River. Round goby were first observed in cormorant diets in 2003 and by 2006 were the main fish consumed at two of the three colonies. The time interval it took from the first appearance of round goby in the diet at a colony to when goby were the dominant prey species varied by island, ranging from two to five years. Daily fish consumption at each cormorant colony increased significantly from the pre-round goby to post-round goby period. The mean annual biomass of yellow perch consumed decreased significantly during the post-round goby period at the three colonies. Reduced consumption of yellow perch by cormorants may alleviate suspected localized impacts on perch near some of the larger river colonies.

  20. Autochthonous Gut Bacteria in Two Indian Air-breathing Fish, Climbing Perch (Anabas testudineus) and Walking Catfish (Clarias batrachus): Mode of Association, Identification and Enzyme Producing Ability.

    PubMed

    Banerjee, Goutam; Dan, Suhas K; Nandi, Ankita; Ghosh, Pinki; Ray, Arun K

    2015-01-01

    Scanning electron microscopy (SEM) was used to define the location of epithelium-associated bacteria in the gastrointestinal (GI) tract of two Indian air-breathing fish, the climbing perch (Anabas testudineus) and walking catfish (Clarias batrachus). The SEM examination revealed substantial numbers of rod shaped bacterial cells associated with the microvillus brush borders of enterocytes in proximal (PI) and distal regions (DI) of the GI tract of both the fish species. Ten (two each from the PI and DI of climbing perch and three each from the PI and DI of walking catfish) isolated bacterial strains were evaluated for extracellular protease, amylase and cellulase production quantitatively. All the bacterial strains exhibited high cellulolytic activity compared to amylolytic and proteolytic activites. Only two strains, CBH6 and CBH7, isolated from the DI of walking catfish exhibited high proteolytic activity. Maximum cellulase activity was exhibited by the strain, CBF2, isolated from the PI of climbing perch. Six most promising enzyme-producing adherent bacterial strains were identified by 16S rDNA gene sequence analysis. The strain ATH1 (isolated from climbing perch) showed high similarity fo Bacillus amyloliquefaciens whereas, the remaining five strains (isolated from walking catfish) were most closely related to Bacillus licheniformis.

  1. Species richness and diversity of the parasites of two predatory fish species - perch (Perca fluviatilis Linnaeus, 1758) and zander (Sander lucioperca Linnaeus, 1758) from the Pomeranian Bay.

    PubMed

    Bielat, Iwona; Legierko, Monika; Sobecka, Ewa

    2015-01-01

    Pomeranian Bay as an ecotone is a transition zone between two different biocenoses, which is characterized by an increase in biodiversity and species density. Therefore, Pomeranian Bay is a destination of finding and reproductive migrations of fish from the rivers entered the area. The aim of the study was to compare parasitic fauna of two predatory fish species from the Pomeranian Bay, collected from the same fishing grounds at the same period. A total of 126 fish studied (53 perches and 73 zanders) were collected in the summer 2013. Parasitological examinations included: skin, fins, gills, vitreous humour and lens of the eye, mouth cavity, body cavity and internal organs. Apart from the prevalence and intensity of infection (mean, range) the parasite communities of both fish species were compared. European perch and zander were infected with parasites from five different taxonomic units. The most numerous parasites were Diplostomum spp. in European perch and Bucephalus polymorphus in zander. The prevalence of infection of European perch ranged from 5.7% (Diphyllobothrium latum) to 22.3% (Diplostomum spp.) and for zander from 1.4% (Ancyrocephalus paradoxus, Hysterothylacium aduncum) to 12.3% (Bucephalus polymorphus). Different composition of the parasitic fauna is likely due to the different biology of both fish species.

  2. Acute and chronic nitrite toxicity in juvenile pike-perch (Sander lucioperca) and its compensation by chloride.

    PubMed

    Wuertz, S; Schulze, S G E; Eberhardt, U; Schulz, C; Schroeder, J P

    2013-05-01

    Pike-perch Sander lucioperca is currently considered as one of the most promising candidates for production in freshwater recirculation aquaculture systems (RAS). Here, due to the lack of studies on nitrite (NO(2)(-)) toxicity in pike-perch, a flow-through exposure at 0, 0.44, 0.88, 1.75, 3.5, 7, 14 and 28 mg/L NO(2)(-)-N was carried out to determine the acute and chronic toxicity over a period of 32 days. In juvenile pike-perch, 120 h LC(50) was 6.1mg/L NO(2)(-)-N and at ≥14 mg/L NO(2)(-)-N all fish had died within 24 h. Chronic exposure revealed a significant build up of NO(2)(-) in the plasma as well as in the muscles at ≥0.44 mg/L NO(2)(-)-N peaking in fish exposed to the highest concentration of 3.5 mg/L NO(2)(-)-N after 32 days. Still, due to high individual variation methemoglobin (MetHb) was only significantly increased (p<0.01) at 3.5 mg/L NO(2)(-)-N. No adverse effects on red blood cells (RBC) and hematocrit were observed in any of the treatments. In a second experiment, compensation of NO(2)(-) toxicity at increasing chloride concentrations (40 (freshwater), 65, 90, 140, 240, 440 mg/L Cl(-)) was observed at a constant exposure of 10 mg/L NO(2)(-)-N for 42 days. At ≥240 mg/L Cl(-), NO(2)(-) build-up in blood plasma and muscle was completely inhibited. At lower Cl(-) concentrations (≤140 mg/L), NO(2)(-) was significantly increased in plasma, but only insignificantly elevated in muscle due to high individual variation. MetHb was increased significantly difference only at 40 mg/L Cl(-) (freshwater control) compared to the control. Again, high individual variations were observed. As a conclusion, S. lucioperca is moderately sensitive towards NO(2)(-) and acceptable levels in RAS should hence not exceed 1.75 mg/L NO(2)(-)-N to avoid MetHb formation. However, based on the 120 h LC(50) and a factor of 0.01 according to Sprague (1971), a NO(2)(-) concentration of ≤0.061 mg/L NO(2)(-)-N is considered as "safe." Thereby, no NO(2)(-) should accumulate in

  3. Geochemistry and hydrology of perched groundwater springs: assessing elevated uranium concentrations at Pigeon Spring relative to nearby Pigeon Mine, Arizona (USA)

    NASA Astrophysics Data System (ADS)

    Beisner, Kimberly R.; Paretti, Nicholas V.; Tillman, Fred D.; Naftz, David L.; Bills, Donald J.; Walton-Day, Katie; Gallegos, Tanya J.

    2016-11-01

    The processes that affect water chemistry as the water flows from recharge areas through breccia-pipe uranium deposits in the Grand Canyon region of the southwestern United States are not well understood. Pigeon Spring had elevated uranium in 1982 (44 μg/L), compared to other perched springs (2.7-18 μg/L), prior to mining operations at the nearby Pigeon Mine. Perched groundwater springs in an area around the Pigeon Mine were sampled between 2009 and 2015 and compared with material from the Pigeon Mine to better understand the geochemistry and hydrology of the area. Two general groups of perched groundwater springs were identified from this study; one group is characterized by calcium sulfate type water, low uranium activity ratio 234U/238U (UAR) values, and a mixture of water with some component of modern water, and the other group by calcium-magnesium sulfate type water, higher UAR values, and radiocarbon ages indicating recharge on the order of several thousand years ago. Multivariate statistical principal components analysis of Pigeon Mine and spring samples indicate Cu, Pb, As, Mn, and Cd concentrations distinguished mining-related leachates from perched groundwater springs. The groundwater potentiometric surface indicates that perched groundwater at Pigeon Mine would likely flow toward the northwest away from Pigeon Spring. The geochemical analysis of the water, sediment and rock samples collected from the Snake Gulch area indicate that the elevated uranium at Pigeon Spring is likely related to a natural source of uranium upgradient from the spring and not likely related to the Pigeon Mine.

  4. Geochemistry and hydrology of perched groundwater springs: assessing elevated uranium concentrations at Pigeon Spring relative to nearby Pigeon Mine, Arizona (USA)

    NASA Astrophysics Data System (ADS)

    Beisner, Kimberly R.; Paretti, Nicholas V.; Tillman, Fred D.; Naftz, David L.; Bills, Donald J.; Walton-Day, Katie; Gallegos, Tanya J.

    2017-03-01

    The processes that affect water chemistry as the water flows from recharge areas through breccia-pipe uranium deposits in the Grand Canyon region of the southwestern United States are not well understood. Pigeon Spring had elevated uranium in 1982 (44 μg/L), compared to other perched springs (2.7-18 μg/L), prior to mining operations at the nearby Pigeon Mine. Perched groundwater springs in an area around the Pigeon Mine were sampled between 2009 and 2015 and compared with material from the Pigeon Mine to better understand the geochemistry and hydrology of the area. Two general groups of perched groundwater springs were identified from this study; one group is characterized by calcium sulfate type water, low uranium activity ratio 234U/238U (UAR) values, and a mixture of water with some component of modern water, and the other group by calcium-magnesium sulfate type water, higher UAR values, and radiocarbon ages indicating recharge on the order of several thousand years ago. Multivariate statistical principal components analysis of Pigeon Mine and spring samples indicate Cu, Pb, As, Mn, and Cd concentrations distinguished mining-related leachates from perched groundwater springs. The groundwater potentiometric surface indicates that perched groundwater at Pigeon Mine would likely flow toward the northwest away from Pigeon Spring. The geochemical analysis of the water, sediment and rock samples collected from the Snake Gulch area indicate that the elevated uranium at Pigeon Spring is likely related to a natural source of uranium upgradient from the spring and not likely related to the Pigeon Mine.

  5. Welfare of organic laying hens kept at different indoor stocking densities in a multi-tier aviary system. II: live weight, health measures and perching.

    PubMed

    Steenfeldt, S; Nielsen, B L

    2015-09-01

    Multi-tier aviary systems, where conveyor belts below the tiers remove the manure at regular intervals, are becoming more common in organic egg production. The area on the tiers can be included in the net area available to the hens (also referred to as usable area) when calculating maximum indoor stocking densities in organic systems within the EU. In this article, results on live weight, health measures and perching are reported for organic laying hens housed in a multi-tier system with permanent access to a veranda and kept at stocking densities (D) of 6, 9 and 12 hens/m2 available floor area, with concomitant increases in the number of hens per trough, drinker, perch and nest space. In a fourth treatment, access to the top tier was blocked reducing vertical, trough, and perch access at the lowest stocking density (D6x). In all other aspects than stocking density, the experiment followed the EU regulations on the keeping of organic laying hens. Hen live weight, mortality and foot health were not affected by the stocking densities used in the present study. Other variables (plumage condition, presence of breast redness and blisters, pecked tail feathers, and perch use) were indirectly affected by the increase in stocking density through the simultaneous reduction in access to other resources, mainly perches and troughs. The welfare of the hens was mostly affected by these associated constraints, despite all of them being within the allowed minimum requirements for organic production in the EU. Although the welfare consequences reported here were assessed to be moderate to minor, it is important to take into account concurrent constraints on access to other resources when higher stocking densities are used in organic production.

  6. Geochemistry and hydrology of perched groundwater springs: assessing elevated uranium concentrations at Pigeon Spring relative to nearby Pigeon Mine, Arizona (USA)

    USGS Publications Warehouse

    Beisner, Kimberly R.; Paretti, Nicholas; Tillman, Fred; Naftz, David L.; Bills, Donald; Walton-Day, Katie; Gallegos, Tanya J.

    2017-01-01

    The processes that affect water chemistry as the water flows from recharge areas through breccia-pipe uranium deposits in the Grand Canyon region of the southwestern United States are not well understood. Pigeon Spring had elevated uranium in 1982 (44 μg/L), compared to other perched springs (2.7–18 μg/L), prior to mining operations at the nearby Pigeon Mine. Perched groundwater springs in an area around the Pigeon Mine were sampled between 2009 and 2015 and compared with material from the Pigeon Mine to better understand the geochemistry and hydrology of the area. Two general groups of perched groundwater springs were identified from this study; one group is characterized by calcium sulfate type water, low uranium activity ratio 234U/238U (UAR) values, and a mixture of water with some component of modern water, and the other group by calcium-magnesium sulfate type water, higher UAR values, and radiocarbon ages indicating recharge on the order of several thousand years ago. Multivariate statistical principal components analysis of Pigeon Mine and spring samples indicate Cu, Pb, As, Mn, and Cd concentrations distinguished mining-related leachates from perched groundwater springs. The groundwater potentiometric surface indicates that perched groundwater at Pigeon Mine would likely flow toward the northwest away from Pigeon Spring. The geochemical analysis of the water, sediment and rock samples collected from the Snake Gulch area indicate that the elevated uranium at Pigeon Spring is likely related to a natural source of uranium upgradient from the spring and not likely related to the Pigeon Mine.

  7. Perch-height specific predation on tropical lizard clay models: implications for habitat selection in mainland neotropical lizards.

    PubMed

    Steffen, John E

    2009-09-01

    Predation has been hypothesized to be a strong selective force structuring communities of tropical lizards. Comparisons of perch height and size-based predation frequencies can provide a unique window into understanding how predation might shape habitat selection and morphological patterns in lizards, especially anoles. Here I use plasticine clay models, placed on the trunks of trees and suspended in the canopy to show that predation frequency on clay models differs primarily according to habitat (canopy vs. trunk-ground), but not according to size. These data are discussed in light of observed lizard abundances in the lowland forests of Costa Rica, and are presented as partial explanation for why fewer lizards are found in tree canopies, and more lizards are found on ground-trunk habitats.

  8. Effect of closed v. intermittent-flow respirometry on hypoxia tolerance in the shiner perch Cymatogaster aggregata.

    PubMed

    Snyder, S; Nadler, L E; Bayley, J S; Svendsen, M B S; Johansen, J L; Domenici, P; Steffensen, J F

    2016-01-01

    This study compares the critical oxygen saturation (O2 crit ) levels of the shiner perch Cymatogaster aggregata obtained using two different methods wherein hypoxia is induced either by the fish's respiration (closed respirometry) or by degassing oxygen with nitrogen (intermittent-flow respirometry). Fish exhibited loss of equilibrium at a higher O2 saturation in the closed respirometry method when compared with the intermittent-flow method. Utilization of closed respirometry yielded O2 crit measurements that were almost twice as high as those obtained with intermittent-flow respirometry. The lower hypoxia tolerance in closed respirometry is consistent with additional stress, caused by a build-up of ammonia and carbon dioxide and a faster rate in dissolved oxygen decline. The results indicate that these two methods of determining hypoxia tolerance in aquatic organisms are not comparable, and that much care should be given to method choice. © 2016 The Fisheries Society of the British Isles.

  9. [Genetic Differentiation of Balkhash Perch Perca schrenki Kessler, 1874 from Lake Balkhash and Alakol Lake System of Kazakhstan].

    PubMed

    Barmintseva, A E; Shalgimbayeva, G M; Asylbekova, S Z; Isbekov, K B; Danko, E K; Mugue, N S

    2015-09-01

    The genetic differentiation of two populations of Balkhash perch Perca schrenki Kessler, 1874 was examined. The study included (1) the population of Lake Balkhash and the Ili River delta, where this species is protected and it is prohibited to catch them and (2) the population of Alakol Lake system, where it is the main commercial species and forms two morphotypes--pelagic and coastal. Analysis of the mitochondrial DNA COI gene and. six microsatellite loci revealed genetic differentiation at the population level, while no statistically significant differences were found at the morphotype level. The results of this study make it possible with high probability to determine the belonging of caught fish to either the commercial (Alakol Lake system) or protected (Lake Balkhash) population.

  10. Susceptibility of Chinese Perch Brain (CPB) Cell and Mandarin Fish to Red-Spotted Grouper Nervous Necrosis Virus (RGNNV) Infection

    PubMed Central

    Tu, Jiagang; Chen, Wenjie; Fu, Xiaozhe; Lin, Qiang; Chang, Ouqin; Zhao, Lijuan; Lan, Jiangfeng; Li, Ningqiu; Lin, Li

    2016-01-01

    Nervous necrosis virus (NNV) is the causative agent of viral encephalopathy and retinopathy (VER), a neurological disease responsible for high mortality of fish species worldwide. Taking advantage of our established Chinese perch brain (CPB) cell line derived from brain tissues of Mandarin fish (Siniperca chuatsi), the susceptibility of CPB cell to Red-Spotted Grouper nervous necrosis virus (RGNNV) was evaluated. The results showed that RGNNV replicated well in CPB cells, resulting in cellular apoptosis. Moreover, the susceptibility of Mandarin fish to RGNNV was also evaluated. Abnormal swimming was observed in RGNNV-infected Mandarin fish. In addition, the cellular vacuolation and viral particles were also observed in brain tissues of RGNNV-infected Mandarin fish by Hematoxylin-eosin staining or electronic microscopy. The established RGNNV susceptible brain cell line from freshwater fish will pave a new way for the study of the pathogenicity and replication of NNV in the future. PMID:27213348

  11. Susceptibility of Chinese Perch Brain (CPB) Cell and Mandarin Fish to Red-Spotted Grouper Nervous Necrosis Virus (RGNNV) Infection.

    PubMed

    Tu, Jiagang; Chen, Wenjie; Fu, Xiaozhe; Lin, Qiang; Chang, Ouqin; Zhao, Lijuan; Lan, Jiangfeng; Li, Ningqiu; Lin, Li

    2016-05-19

    Nervous necrosis virus (NNV) is the causative agent of viral encephalopathy and retinopathy (VER), a neurological disease responsible for high mortality of fish species worldwide. Taking advantage of our established Chinese perch brain (CPB) cell line derived from brain tissues of Mandarin fish (Siniperca chuatsi), the susceptibility of CPB cell to Red-Spotted Grouper nervous necrosis virus (RGNNV) was evaluated. The results showed that RGNNV replicated well in CPB cells, resulting in cellular apoptosis. Moreover, the susceptibility of Mandarin fish to RGNNV was also evaluated. Abnormal swimming was observed in RGNNV-infected Mandarin fish. In addition, the cellular vacuolation and viral particles were also observed in brain tissues of RGNNV-infected Mandarin fish by Hematoxylin-eosin staining or electronic microscopy. The established RGNNV susceptible brain cell line from freshwater fish will pave a new way for the study of the pathogenicity and replication of NNV in the future.

  12. Gonadal histopathology following nickel intoxication in the giant gaurami Colisa fasciatus (Bloch and Schneider), a freshwater tropical perch

    SciTech Connect

    Nath, K.; Kumar, N. )

    1990-08-01

    Large variety of data regarding toxic effects of nickel on mammals has been reported. Nickel refinery workers had increased mortality from lung or sinonasal cancers. In human populations exposed to nickel and chromium compounds, chromosomal abberations have been reported. Biochemical as well as histopathological alterations arising from nickel exposure in mammals have also been documented. Very scanty data is available concerning histopathological impact of nickel on fish tissues. However, to the authors' knowledge, there are no reports available on the fish gonads of either sex encountered with nickel. The present study appears to be the first report on the topic. Therefore, in the present investigation impact of nickel on the histological architecture of gonads of both sexes of a freshwater tropical perch, Colisa fasciatus have been assessed.

  13. Should Controls With Respiratory Symptoms Be Excluded From Case-Control Studies of Pneumonia Etiology? Reflections From the PERCH Study.

    PubMed

    Higdon, Melissa M; Hammitt, Laura L; Deloria Knoll, Maria; Baggett, Henry C; Brooks, W Abdullah; Howie, Stephen R C; Kotloff, Karen L; Levine, Orin S; Madhi, Shabir A; Murdoch, David R; Scott, J Anthony G; Thea, Donald M; Driscoll, Amanda J; Karron, Ruth A; Park, Daniel E; Prosperi, Christine; Zeger, Scott L; O'Brien, Katherine L; Feikin, Daniel R

    2017-06-15

    Many pneumonia etiology case-control studies exclude controls with respiratory illness from enrollment or analyses. Herein we argue that selecting controls regardless of respiratory symptoms provides the least biased estimates of pneumonia etiology. We review 3 reasons investigators may choose to exclude controls with respiratory symptoms in light of epidemiologic principles of control selection and present data from the Pneumonia Etiology Research for Child Health (PERCH) study where relevant to assess their validity. We conclude that exclusion of controls with respiratory symptoms will result in biased estimates of etiology. Randomly selected community controls, with or without respiratory symptoms, as long as they do not meet the criteria for case-defining pneumonia, are most representative of the general population from which cases arose and the least subject to selection bias. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

  14. The effect of mammalian herbivory on inflorescence architecture in ornithophilous Babiana (Iridaceae): implications for the evolution of a bird perch.

    PubMed

    de Waal, Caroli; Barrett, Spencer C H; Anderson, Bruce

    2012-06-01

    The showiness of floral displays is usually explained as an adaptation to attract pollinators. However, selection for less attractive displays imposed by non-pollinating agents, particularly herbivores, may balance pollinator-driven selection for highly visible inflorescences. We investigated whether inflorescence architecture, particularly the unusual ground-level flowering associated with a specialized bird perch in Babiana ringens may have originated, in part, as an adaptive response to mammalian herbivory. We measured levels of herbivory by antelope in populations of B. hirsuta, the putative sister species of B. ringens, which possesses the likely ancestral form of inflorescence architecture. To test for position-dependent effects of herbivory on flowers, we compared the herbivory rates and seed production of manipulated inflorescences in a field experiment. We predicted that flowers at the base of inflorescences would suffer less herbivory than those in apical positions. We found herbivore damage to flowers in 50% of naturally occurring B. hirsuta plants. Manipulated inflorescences with only basal flowers, and consequently similar inflorescence architecture to B. ringens, experienced significantly lower herbivory and higher seed set than inflorescences manipulated to have only apical flowers. Our results are consistent with the hypothesis that position-dependent herbivory on inflorescences could have played a role in the evolution of inflorescence design. More specifically, position-dependent herbivory may have selected for the loss of apical flowers. Position-dependent herbivory may have contributed toward the evolution of a naked inflorescence axis, a structure that characterizes B. ringens and functions as a bird perch facilitating cross-pollination by sunbirds.

  15. Polychlorinated biphenyls and Hudson River white perch: implications for population-level ecological risk assessment and risk management.

    PubMed

    Barnthouse, Lawrence W; Glaser, David; DeSantis, Liane

    2009-07-01

    Risk assessments and risk management decisions concerning risks to wild fish populations resulting from exposures to polychlorinated biphenyls (PCBs) and related chemicals have been based primarily on observations of effects of chemicals on individual organisms. Although the development and application of population-level ecological risk-assessment methods is proceeding at a rapid pace, the organism-level approach is still being justified by arguments that population-level ecological risk assessment is in an early stage of development and has not been shown to be reliable. This article highlights the importance of including population-level effects in risk-management decision-making, by examining the effects of exposures to PCBs on fish populations inhabiting the Hudson River, New York, USA, a system in which data have been collected for approximately 30 y concerning both concentrations of PCBs in sediment and fish tissue and the abundance and reproduction of exposed fish populations. We previously tested hypotheses concerning the effects of PCBs on the striped bass population of the Hudson River, and found that the available data conflicted with all of these hypotheses. Here, we report results of similar analyses of effects of historic PCB exposures on the Hudson River white perch population, using an extended data set that recently became available. As with striped bass, we found no correlation between maternal PCB tissue concentrations and any measure of reproductive success in Hudson River white perch during the 30-y period covered by the data set. Together with results of studies performed on fish populations exposed to PCBs at other sites, our results clearly demonstrate that physiological and genetic adaptation, biological compensation, and other ecological processes influence responses of fish populations to PCB exposures and should be considered in risk management decision-making.

  16. Effects of sex steroids and their inhibitors on endocrine parameters and gender growth differences in Eurasian perch (Perca fluviatilis) juveniles.

    PubMed

    Mandiki, Syaghalirwa N M; Babiak, Igor; Bopopi, Johny M; Leprieur, Fabien; Kestemont, Patrick

    2005-02-01

    Sex steroid inhibitors were used to characterize the effects of 17beta-estradiol (E2) and testosterone (T) on the sexual growth dimorphism of Eurasian perch juveniles. In experiment 1, growth responses to different doses of either E2 (25, 50, 75, and 100 mgkg(diet)-1) or fadrozole (Fa; 50 and 100 mgkg(diet)-1) were compared in triplicate tanks of 30 fish each during 85 days. In experiment 2, five diets containing (50 mgkg(diet)-1) Tamoxifen (Ta), Flutamide (Flu), Fa, E2, and T were tested in triplicate tanks of 20 fish each during 90 days. Steroid supplementation or inhibition increased or decreased E2 and T plasma levels. Moreover, E2 treatment induced a higher plasma vitellogenin level but decreased triidothyronine levels. Brain aromatase activity (AA) was lower in Fa-treated fish than in other groups. In experiment 1, E2 supplementation did not promote growth, but high doses had negative effects as did Fa. In experiment 2, a greater growth response was observed only in E2-treated females in relation to higher food intake (FI) not feeding efficiency. Fa also promoted growth and FI both in females and males during the last month of the experiment. Other treatments did not affect growth, but T treatment decreased FI in males. In conclusion, the results did not provide clear evidence for E2 action on sexual growth dimorphism, but showed that testosterone may decrease growth in males by decreasing food intake in Eurasian perch. Therefore, the acceleration of male-to-female growth differences with age may not be a result of promotion of growth in females by estrogens, but a consequence of a reduction in growth by increased secretion of androgens in males.

  17. De novo transcriptome sequencing and analysis of male, pseudo-male and female yellow perch, Perca flavescens

    PubMed Central

    Li, Yan-He; Wang, Han-Ping; Yao, Hong; O’Bryant, Paul; Rapp, Dean; Guo, Liang; Waly, Eman A.

    2017-01-01

    Transcriptome sequencing could facilitate discovery of sex-biased genes, biological pathways and molecular markers, which could help clarify the molecular mechanism of sex determination and sexual dimorphism, and assist with selective breeding in aquaculture. Yellow perch has unique gonad system and sexual dimorphism and is an alternative model to study mechanism of sex determination, sexual dimorphism and sexual selection. In this study, we performed the de novo assembly of yellow perch gonads and muscle transcriptomes by high throughput Illumina sequencing. A total of 212,180 contigs were obtained, ranging from 127 to 64,876 bp, and N50 of 1,066 bp. The assembly RNA-Seq contigs (≥200bp) were then used for subsequent analyses, including annotation, pathway analysis, and microsatellites discovery. No female- and pseudo-male-biased genes were involved in any pathways while male-biased genes were involved in 29 pathways, and neuroactive ligand receptor interaction and enzyme of trypsin (enzyme code, EC: 3.4.21.4) was highly involved. Pyruvate kinase (enzyme code, EC: 2.7.1.40), which plays important roles in cell proliferation, was highly expressed in muscles. In addition, a total of 183,939 SNPs, 11,286 InDels and 41,479 microsatellites were identified. This study is the first report on transcriptome information in Percids, and provides rich resources for conducting further studies on understanding the molecular basis of sex determinations, sexual dimorphism, and sexual selection in fish, and for population studies and marker-assisted selection in Percids. PMID:28158238

  18. Ocean bowling

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    Coach Scott Carpenter, a biology teacher at Lexington High School in Massachusetts, says that “some [students] want to show that they can win on a football field, and some want to show that they know science better than anyone else.”His team of four sophomores and one senior proved their mettle when they won the 1998 National Ocean Science Bowl on April 27.

  19. Ocean Optics

    DTIC Science & Technology

    2014-05-01

    sensing and lidar , through measurements and models. 15. SUBJECT TERMS Remote sensing , ocean optics, lidar , underwater imaging, underwater turbulence...scanning system taking advantage of compressive sensing imaging techniques (B. O^ang et al.). Modeling is key in system design and performance...effect has been simulated using a fvlonte Carlo method (Z. Xu and D. K. P. Yue). Active sensing by the means of lidar eliminates many of the issues

  20. Oceans '88

    SciTech Connect

    Not Available

    1988-01-01

    These proceedings discuss the following papers: Solid waste disposal crisis; Plastics in Ocean; Continental shelf environmental research; Seafood technology advancements; Gulf of Mexico chemosynthetic petroleum seep communities; Water reuse on onshore mariculture and processing facilities; Oil and gas industry conflicts on the outer continental shelf; Cumulative environmental effects of the oil and gas leasing program; Oil and gas exploration; and Oil and gas resource management; Aids to navigation systems and equipment; and Surveillance experiments.

  1. Oceanic Lidar

    NASA Technical Reports Server (NTRS)

    Carder, K. L. (Editor)

    1981-01-01

    Instrument concepts which measure ocean temperature, chlorophyll, sediment and Gelbstoffe concentrations in three dimensions on a quantitative, quasi-synoptic basis were considered. Coastal zone color scanner chlorophyll imagery, laser stimulated Raman temperaure and fluorescence spectroscopy, existing airborne Lidar and laser fluorosensing instruments, and their accuracies in quantifying concentrations of chlorophyll, suspended sediments and Gelbstoffe are presented. Lidar applications to phytoplankton dynamics and photochemistry, Lidar radiative transfer and signal interpretation, and Lidar technology are discussed.

  2. Oceanic Hotspots

    NASA Astrophysics Data System (ADS)

    Batiza, Rodey

    2004-10-01

    The Wilson-Morgan hypothesis that fixed mantle plumes rising from deep in Earth's mantle give rise to linear island and seamount chains like Hawaii has been a leading idea in planetary geodynamics for many decades. However, the notion that these ascending columns of buoyant mantle material are fixed relative to each other or to a fixed reference frame has been questioned because the mean regional flow of the mantle (the so-called mantle wind) would be expected to entrain them and waft them about. Lately, even more fundamental questions have been raised regarding the existence of deep mantle conduits. In fact, the subject of plumes has become quite controversial, with important implications for ideas of mantle convection, Earth's differentiation, and planetary magma budgets and cooling. The appearance of Oceanic Hotspots: Intraplate Submarine Magmatism and Tectonics is thus timely. The 14 chapters contained in this nicely produced volume reflect in part the successful Franco-German collaboration spanning more than 17 years (1986 to present) and 15 expeditions to largely uncharted and unexplored regions of the South Pacific Ocean. The editors intended to produce a comprehensive multidisciplinary overview of oceanic plumes in this region, and in this they have succeeded, with both review and research chapters. Most papers document new discoveries and contain new data and/or new and original thinking, whereas others provide a broad overview and synthesis of existing data.

  3. Cadmium-handling strategies in two chronically exposed indigenous freshwater organisms--the yellow perch (Perca flavescens) and the floater mollusc (Pyganodon grandis).

    PubMed

    Campbell, Peter G C; Giguère, Anik; Bonneris, Emmanuelle; Hare, Landis

    2005-03-25

    Laboratory experiments on a variety of aquatic organisms suggest that metallothionein-like proteins (MT) play an important role in the regulation of essential metals, and in the sequestration and detoxification of non-essential metals (e.g., Cd). However, the importance of metallothionein production relative to alternative strategies of metal detoxification, and its effectiveness in metal detoxification, remain largely unexplored in field situations. In the present study we explored metal-handling strategies in an adult benthic bivalve (Pyganodon grandis) and in juvenile yellow perch (Perca flavescens), exposed to Cd in their natural habitat. The two biomonitor species were collected from lakes located along a Cd concentration gradient. Ambient dissolved Cd concentrations were determined by in situ dialysis as a measure of metal exposure. Sub-cellular Cd partitioning was determined in target tissues (bivalve gills and digestive gland; perch liver) by differential centrifugation, and metallothionein was measured independently by a mercury-saturation assay in the bivalve tissues. Malondialdehyde concentrations were measured as a potential indicator of oxidative stress. Ambient dissolved Cd concentrations ranged from 0.06 to 0.57 nM in the nine lakes from which bivalves were collected, and from < 0.3 to 6.7 nM in the eight lakes from which yellow perch were sampled. Bioaccumulated Cd also varied from lake to lake, more so for the bivalve than for the yellow perch; the [Cd]max/[Cd]min ratios for the various tissues decreased in the order: bivalve gill Cd 28 > bivalve digestive gland Cd 18 > perch hepatic Cd 14. In the two lakes that were common to both the bivalve and perch studies, i.e. lakes Opasatica and Vaudray, accumulated Cd concentrations were consistently higher in the bivalve than in the perch. Cadmium-handling strategies were similar in the bivalve digestive gland and perch liver, in that Cd was mainly associated with the heat-stable protein (HSP) fraction

  4. An update of the distribution of selected radiochemical and chemical constituents in perched ground water, Idaho National Laboratory, Idaho, Emphasis 1999-2001

    USGS Publications Warehouse

    Davis, Linda C.

    2006-01-01

    Radiochemical and chemical wastes generated at facilities at the Idaho National Laboratory (INL) were discharged since 1952 to infiltration ponds at the Reactor Technology Complex (RTC) (known as the Test Reactor Area [TRA] until 2005), and the Idaho Nuclear Technology and Engineering Center (INTEC) and buried at the Radioactive Waste Management Complex (RWMC). Disposal of wastewater to infiltration ponds and infiltration of surface water at waste burial sites resulted in formation of perched ground water in basalts and in sedimentary interbeds above the Snake River Plain aquifer. Perched ground water is an integral part of the pathway for waste-constituent migration to the aquifer. The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Energy, maintains ground-water monitoring networks at the INL to determine hydrologic trends, and to monitor the movement of radiochemical and chemical constituents in wastewater discharged from facilities to both perched ground water and the aquifer. This report presents an analysis of water-quality and water-level data collected from wells completed in perched ground water at the INL during 1999-2001, and summarizes historical disposal data and water-level-and water-quality trends. At the RTC, tritium, strontium-90, cesium-137, dissolved chromium, chloride, sodium, and sulfate were monitored in shallow and deep perched ground water. In shallow perched ground water, no tritium was detected above the reporting level. In deep perched ground water, tritium concentrations generally decreased or varied randomly during 1999-2001. During October 2001, tritium concentrations ranged from less than the reporting level to 39.4?1.4 picocuries per milliliter (pCi/mL). Reportable concentrations of tritium during July-October 2001 were smaller than the reported concentrations measured during July-December 1998. Tritium concentrations in water from wells at the RTC were likely affected by: well's distance from the

  5. The Oceans

    NASA Astrophysics Data System (ADS)

    Karlsten, Jill

    For many practitioners of the marine sciences, including myself, one of the most alluring aspects of investigating the oceans is the need to marry the scientific disciplines. The complex linkages among geological, chemical, physical, and biological processes that govern the behavior and evolution of nearly 60% of the Earth's surface are fascinating and often surprising. Making progress in decoding this planetary fugue requires investigative strategies that fly squarely in the face of the increasing specialization that characterizes most modern scientific research. The successful oceanographer must endeavor to see the forest as well as the trees, or perhaps more fittingly, the kelp.

  6. Intestinal parasite Acanthocephalus lucii (Acanthocephala) from European perch (Perca fluviatilis) as a bioindicator for lead pollution in the stream "Jevanský potok" near Prague, Czech Republic.

    PubMed

    Jankovská, Ivana; Miholová, Daniela; Petrtýl, Miloslav; Romočuský, Stěpán; Kalous, Lukáš; Vadlejch, Jaroslav; Cadková, Zuzana; Langrová, Iva

    2011-03-01

    Lead concentrations in the tissues of perch and its parasites were determined as mg/kg dw. Lead was found at higher concentrations in the acanthocephalans (11.56) than in different tissues (liver, gonads and muscle with skin and bone) of perch. With respect to fish tissues, the highest concentrations of lead were present in the liver (1.24), followed by the gonads (0.57) whereas the lowest concentrations were in the muscle with skin and bone (0.21). The bioconcentration factors for lead indicated that parasites accumulate metals to a higher degree than fish tissues--lead concentrations in acanthocephalans were 9.32, 19.27 and 55.05 higher than in liver, gonads and muscles of host, respectively.

  7. Identification of grouper (Epinephelus guaza), wreck fish (Polyprion americanus), and Nile perch (Lates niloticus) fillets by polyclonal antibody-based enzyme-linked immunosorbent assay.

    PubMed

    Asensio, Luis; González, Isabel; Rodríguez, Miguel A; Mayoral, Belén; López-Calleja, Inés; Hernández, Pablo E; García, Teresa; Martín, Rosario

    2003-02-26

    An indirect enzyme-linked immunosorbent assay (ELISA) has been developed for the species identification of grouper (Epinephelus guaza), wreck fish (Polyprion americanus), and Nile perch (Lates niloticus) fillets. The assay was performed in two different formats, microtiter plates and immunostick tubes, and uses polyclonal antibodies raised in rabbits against muscle-soluble proteins of grouper (anti-GSP), wreck fish (anti-WSP), and Nile perch (anti-PSP). The antibodies were made species-specific by blocking them with the heterologous soluble muscle proteins. Immunorecognition of polyclonal antibodies adsorbed to their specific fish samples was made with swine antirabbit immunoglobulins conjugated to the enzyme horseradish peroxidase. Subsequent enzymatic conversion of the substrate allowed unequivocal identification of the species studied.

  8. Planet Ocean

    NASA Astrophysics Data System (ADS)

    Afonso, Isabel

    2014-05-01

    A more adequate name for Planet Earth could be Planet Ocean, seeing that ocean water covers more than seventy percent of the planet's surface and plays a fundamental role in the survival of almost all living species. Actually, oceans are aqueous solutions of extraordinary importance due to its direct implications in the current living conditions of our planet and its potential role on the continuity of life as well, as long as we know how to respect the limits of its immense but finite capacities. We may therefore state that natural aqueous solutions are excellent contexts for the approach and further understanding of many important chemical concepts, whether they be of chemical equilibrium, acid-base reactions, solubility and oxidation-reduction reactions. The topic of the 2014 edition of GIFT ('Our Changing Planet') will explore some of the recent complex changes of our environment, subjects that have been lately included in Chemistry teaching programs. This is particularly relevant on high school programs, with themes such as 'Earth Atmosphere: radiation, matter and structure', 'From Atmosphere to the Ocean: solutions on Earth and to Earth', 'Spring Waters and Public Water Supply: Water acidity and alkalinity'. These are the subjects that I want to develop on my school project with my pupils. Geographically, our school is located near the sea in a region where a stream flows into the sea. Besides that, our school water comes from a borehole which shows that the quality of the water we use is of significant importance. This project will establish and implement several procedures that, supported by physical and chemical analysis, will monitor the quality of water - not only the water used in our school, but also the surrounding waters (stream and beach water). The samples will be collected in the borehole of the school, in the stream near the school and in the beach of Carcavelos. Several physical-chemical characteristics related to the quality of the water will

  9. Change in diel catchability of young-of-year yellow perch associated with establishment of dreissenid mussels

    USGS Publications Warehouse

    Stapanian, Martin A.; Kocovsky, Patrick M.; Adams, Jean V.

    2009-01-01

    1. Non-native mussels have increased water clarity in many lakes and streams in North America and Europe. Diel variation in catchability of some fish species has been linked to visibility during survey trawls (used to measure escapement). 2. Water clarity increased in nearshore areas of western Lake Erie by the early 1990s, following passage of legislation in 1972 to improve water quality (e.g. reduce phosphorus loading) and the invasion of dreissenid mussels (Dreissena spp.) beginning in 1987. 3. We hypothesised that increased water clarity in Lake Erie resulted in decreased catchability of young-of-year (age-0) yellow perch (Perca flavescens Mitchill) during daylight compared to during night. We used a two-tiered modelling approach to test this hypothesis on the ratio (R) of catch per hour (CPH) during night to CPH during daylight in bottom trawl surveys conducted during 1961-2005. 4. First, we examined seven a priori models. The first model, the 'null' model, represented no change in R over time. Three more models tested whether the timing of the change in R was associated with passage of water quality legislation only, dreissenids only (two-period models) and both legislation and dreissenids (three-period models). Three additional models included a 3-year lag before the effects of legislation, dreissenids or both occurred. Secondly, all possible two- and three-period models with a minimum of 2 years per time period were explored a posteriori. The a posteriori procedure determined the temporal transitions to higher R that were best supported by the data, without regard to a priori hypotheses. 5. Night CPH was greater than daylight CPH in 3 of 11 years during 1961-72, in 10 of 15 years during 1973-87, and in 14 of 18 years during 1988-2005. During 1991-2005 night CPH exceeded daylight CPH in all years except one, and night CPH was more than twice daylight CPH in 10 years during this period. 6. The best a priori model had two periods, with a break between 1990 and

  10. Mapping Weak, Altered Zones and Perched Water With Aerogeophysical Measurements at Mount Adams, Washington: Implications for Volcanic Instability

    NASA Astrophysics Data System (ADS)

    Finn, C. A.; Deszcz-Pan, M.; Anderson, E. D.; Horton, R.

    2006-12-01

    Hydrothermally altered rocks, particularly if water saturated, can weaken stratovolcanoes. This increases the potential for catastrophic sector collapses that can lead to destructive debris flows. Evaluating the hazards associated with such alteration is difficult, because alteration has been mapped on few active volcanoes and the distribution and intensity of subsurface alteration and location of perched water tables are largely unknown on any active volcano. At Mount Adams, some Holocene debris flows contain abundant hydrothermal minerals derived from collapse of an altered edifice. Intense hydrothermal alteration can significantly reduce the resistivity (from hundreds to tens ohm-m) and magnetization of volcanic rocks. These changes can be identified with helicopter electromagnetic and magnetic measurements and visualized in 3D. 100 m is the greatest depth that the lowest frequency electromagnetic data could penetrate into the low resistivity, altered zones; outside the altered zones, the depth of penetration was up to 300 m. Total-field magnetic data can detect magnetization variations to several thousand meters depth. Electromagnetic and magnetic data, combined with geological mapping and rock property measurements, indicate the presence of appreciable thicknesses of hydrothermally altered rock in the central core of Mount Adams north of the summit. We identify steep cliffs at the western edge of this zone as the likely source for future large debris flows. Water, and perhaps melted ice, is needed as a lubricant to transform debris avalanches into lahars. Therefore, knowing the distribution of both is important for hazard assessments. Over the low resistivity summit, the electromagnetic data detected ice with a thickness of 0 to about 80 m and an estimated volume of up to 0.1 km3. Over resistive ridges ice thicknesses could not be determined. The electromagnetic data also identified perched water tables in the brecciated core of the upper 300 m of the volcano

  11. Safety of oxytetracycline (Terramycin TM-100F) administered in feed to hybrid striped bass, walleyes, and yellow perch

    USGS Publications Warehouse

    Gaikowski, M.P.; Wolf, J.C.; Schleis, S.M.; Gingerich, W.H.

    2003-01-01

    Oxytetracycline (Terramycin TM-100F, a medicated premix containing oxytetracycline at 220 g/kg) is approved in the United States to control certain systemic bacterial diseases of salmon and catfish when fed at a rate of 55-82.5 mg per kilogram of bodyweight per day for 10 d. Although oxytetracycline may also control certain systemic bacterial infections in coolwater or scaled warmwater fish, no safety data for such species are available. Our objective was to determine the safety of oxytetracycline administered in feed at nominal doses of 0, 82.5, 248, or 413 mg??kg-1??d-1 to yellow perch Perca flavescens and hybrid striped bass (striped bass Morone saxatilis x white bass M. chrysops) for 10 d and to walleye Sander vitreus (formerly Stizostedion vitreum) for 20 d. Yellow perch and hybrid striped bass consumed 50% to 100% of the diet, whereas walleye feed consumption was occasionally less than 50% of the diet. Feed or fecal material was present in the gastrointestinal tract of all necropsied walleyes except for one control fish. The single growth effect was that hybrid striped bass offered a nominal dose of 413 mg??kg-1??d-1 were significantly smaller than untreated controls. Oxytetracycline-related histopathological findings were limited to walleyes and were of low severity. The histopathological findings included decreased hematopoietic-lymphopoietic (H&L) tissue in the anterior kidneys, diffuse hyperplasia of the gill filament epithelium, and a decreased prevalence of fish with eosinophilic droplets in their renal tubular epithelial cells. Although the incidence of decreased H&L tissue tended to increase in proportion to oxytetracycline dose, this finding was statistically significant only for fish that received a nominal dose of 413 mg??kg-1??d-1. Given the pathogenicity of the types of bacteria that are controlled by oxytetracycline treatment and the long history of its use in major aquaculture species, the relative risk of the minor oxytetracycline

  12. Application of random amplified polymorphic DNA (RAPD) analysis for identification of grouper (Epinephelus guaza), wreck fish (Polyprion americanus), and Nile perch (Lates niloticus) fillets.

    PubMed

    Asensio, Luis; González, Isabel; Fernández, Alicia; Rodríguez, Miguel A; Lobo, Esther; Hernández, Pablo E; García, Teresa; Martín, Rosario

    2002-02-01

    A random amplified polymorphic DNA (RAPD) method was developed for the specific identification of grouper (Epinephelus guaza), wreck fish (Polyprion americanus), and Nile perch (Lates niloticus) fillets. Using two different reaction primers (S1 and L1), RAPD analysis produced clear fingerprints from which the three fish species could be easily identified. This approach is rapid and reliable and offers the potential to detect fraudulent or unintentional mislabeling of these species in routine seafood authentication analysis.

  13. Depletion of the chloramine-T marker residue, para-toluenesulfonamide, from skin-on fillet tissue of hybrid striped bass, rainbow trout, and yellow perch

    USGS Publications Warehouse

    Meinertz, J.R.; Stehly, G.R.; Greseth, Shari L.; Gaikowski, M.P.; Gingerich, W.H.

    2004-01-01

    Waterborne exposure to n-sodium-n-chloro-p-toluenesulfonamide (chloramine-T) is an effective treatment for controlling fish mortalities caused by bacterial gill disease (BGD). Currently, data are being generated to gain United States Food and Drug Administration (FDA) approval for the use of chloramine-T in aquaculture. As part of the data required for an approval, depletion of the chloramine-T marker residue (para-toluenesulfonamide [p-TSA]) from the edible fillet tissue of exposed fish must be determined. Hybrid striped bass (Morone saxatilis??Morone chrysops; mean weight 357 g), rainbow trout (Oncorhynchus mykiss; mean weight 457 g), and yellow perch (Perca flavescens; mean weight 144 g) were exposed to 20 mg/l of chloramine-T for 60 min on 4 consecutive days (the most aggressive treatment expected for approved use in the United States). Groups of fish (n=15 or 19) were sampled immediately after the last treatment and periodically through 48 or 168 h after the treatment phase. Duplicate subsamples of skin-on fillet tissue from each fish were analyzed for p-TSA. Mean p-TSA concentrations in fillet tissue from fish sampled immediately after the last treatment were 142 ng/g (hybrid striped bass), 97 ng/g (rainbow trout), and 150 ng/g (yellow perch). Mean p-TSA concentrations at terminal sample times were 94 (168 h; hybrid striped bass), 74 (48 h; rainbow trout), and 35 ng/g (168 h; yellow perch). The half-lives of p-TSA in fillet tissue from fish near or at market size were 11.4 (hybrid striped bass), 4.3 (rainbow trout), and 3.2 days (yellow perch).

  14. Comparative susceptibility among three stocks of yellow perch, Perca flavescens (Mitchill), to viral haemorrhagic septicaemia virus strain IVb from the Great Lakes.

    PubMed

    Olson, W; Emmenegger, E; Glenn, J; Winton, J; Goetz, F

    2013-08-01

    The Great Lakes strain of viral haemorrhagic septicaemia virus IVb (VHSV-IVb) is capable of infecting a wide number of naive species and has been associated with large fish kills in the Midwestern United States since its discovery in 2005. The yellow perch, Perca flavescens (Mitchill), a freshwater species commonly found throughout inland waters of the United States and prized for its high value in sport and commercial fisheries, is a species documented in several fish kills affiliated with VHS. In the present study, differences in survival after infection with VHSV IVb were observed among juvenile fish from three yellow perch broodstocks that were originally derived from distinct wild populations, suggesting innate differences in susceptibility due to genetic variance. While all three stocks were susceptible upon waterborne exposure to VHS virus infection, fish derived from the Midwest (Lake Winnebago, WI) showed significantly lower cumulative % survival compared with two perch stocks derived from the East Coast (Perquimans River, NC and Choptank River, MD) of the United States. However, despite differences in apparent susceptibility, clinical signs did not vary between stocks and included moderate-to-severe haemorrhages at the pelvic and pectoral fin bases and exophthalmia. After the 28-day challenge was complete, VHS virus was analysed in subsets of whole fish that had either survived or succumbed to the infection using both plaque assay and quantitative PCR methodologies. A direct correlation was identified between the two methods, suggesting the potential for both methods to be used to detect virus in a research setting.

  15. Microbiological properties and biogenic amines of whole pike-perch (Sander lucioperca, linnaeus 1758): a perspective on fish safety during postharvest handling practices and frozen storage.

    PubMed

    Ehsani, Ali; Jasour, Mohammad Sedigh

    2012-12-01

    The biogenic amines (tyramine, histamine, cadaverine, and puterscine) and microbiological properties (mesophilic, psychrotrophic, and Pseudomonas spp.) of whole pike-perch (Sander lucioperca) was investigated during 2 d prestorage icing and 90 d frozen storage (-24 °C). At the end of ice storage, a noticeable increase only was found for puterscine level (P < 0.05), and microbial loads of fish increased in comparison with fresh fish (P < 0.05). During the frozen storage, as time passed, a continuous increase of biogenic amines and decrease of bacterial load (except for Pseudomonas spp. at the last 30 d) was detected (P < 0.05). The total contents of biogenic amines ranged from 6.24 to 91.76 μg/g during the investigated period. Puterscine was the major amine detected in pike-perch and its concentration varied between 1.75 and 56.95 μg/g; due to a more step-wise increase it was a good quality indicator. At the end of storage, all of the obtained values are below the tolerable maximum amounts based on available regulations. Based on biogenic amines content and microbial load, it could be concluded that pike-perch can be consumed without any health risks after 2 d icing condition and 90 d frozen storage.

  16. Learn about Ocean Dumping

    EPA Pesticide Factsheets

    Ocean dumping is regulated by the Marine Protection, Research and Sanctuaries Act (MPRSA). Learn about ocean dumping regulation including what materials can and cannot be dumped, the Ocean Dumping Management Program, and MPRSA history and accomplishments.

  17. Task 1: Whole-body concentrations of elements in kelp bass (Paralabrax clathratus), kelp rockfish (Sebastes atrovirens), and Pacific sanddab (Citharichthys sordidus) from offshore oil platforms and natural areas in the Southern California Bight

    USGS Publications Warehouse

    Love, Milton S.

    2009-01-01

    Resource managers are concerned that offshore oil platforms in the Southern California Bight may be contributing to environmental contaminants accumulated by marine fishes. To examine this possibility, 18 kelp bass (Paralabrax clathratus), 80 kelp rockfish (Sebastes atrovirens), and 98 Pacific sanddab (Citharichthys sordidus) were collected from five offshore oil platforms and 10 natural areas during 2005-2006 for whole-body analysis of 63 elements. The natural areas, which served as reference sites, were assumed to be relatively uninfluenced by contaminants originating from platforms. Forty-two elements were excluded from statistical comparisons for one of three reasons: they consisted of major cations that were unlikely to accumulate to potentially toxic concentrations under ambient exposure conditions; they were not detected by the analytical procedures; or they were detected at concentrations too low to yield reliable quantitative measurements. The remaining 21 elements consisted of aluminum, arsenic, barium, cadmium, chromium, cobalt, copper, gallium, iron, lead, lithium, manganese, mercury, nickel, rubidium, selenium, strontium, tin, titanium, vanadium, and zinc. Statistical comparisons of these 21 elements indicated that none consistently exhibited higher concentrations at oil platforms than at natural areas. Eight comparisons yielded significant interaction effects between total length (TL) of the fish and the two habitat types (oil platforms and natural areas). This indicated that relations between certain elemental concentrations (i.e., copper, rubidium, selenium, tin, titanium, and vanadium) and habitat type varied by TL of affected fish species. To better understand these interactions, we examined elemental concentrations in very small and very large individuals of affected species. Although significant interactions were detected for rubidium, tin, and selenium in kelp rockfish, the concentrations of these elements did not differ significantly between

  18. Buried soils in a perched dunefield as indicators of late holecene lake-level change in the Lake Superior basin

    USGS Publications Warehouse

    Anderton, John B.; Loope, Walter L.

    1995-01-01

    A stratigraphic analysis of buried soils within the Grand Sable Dunes, a dune field perched 90 m above the southern shore of Lake Superior, reveals a history of eolian activity apparently linked with lake-level fluctuations over the last 5500 yr. A relative rise in the water plane of the Nipissing Great Lakes initially destabilized the lakeward bluff face of the Grand Sable plateau between 5400 and 4600 14C yr B.P. This led to the burial of the Sable Creek soil by eolian sediments derived from the bluff face. Subsequent episodes of eolian activity appear to be tied to similar destabilizing events; high lake levels may have initiated at least four and perhaps eleven episodes of dune building as expressed by soil burials within the dunes. Intervening low lake levels probably correlate with soil profile development, which varies from the well-developed Sable Creek Spodosol catena to thin organic layers containing in-place stumps and tree trunks. Paleoecological reconstructions available for the area do not imply enough climatic change to account for the episodic dune activity. Burial of soils by fine-fraction sediments links dune-building episodes with destabilization of the lower lake-facing bluff, which is rich in fines.

  19. Investigation of the Potential for 90Sr Immobilization in INTEC Perched Water via Microbially Facilitated Calcite Precipitation

    SciTech Connect

    Yoshiko Fujita; Karen E. Wright; William A. Smith

    2006-10-01

    The goal of this work is to evaluate the applicability of a biogeochemical sequestration approach for remediation of 90Sr contamination in perched water zones underlying the Idaho Nuclear Technology and Engineering Center (INTEC). The approach is based on the accelerated co-precipitation of the contaminant in calcite, where the acceleration is catalyzed by the microbial urea hydrolysis. We have previously demonstrated the potential for this remediation mechanism to immobilize strontium. Urea hydrolysis promotes calcite precipitation (and trace metal co-precipitation) by increasing groundwater pH and alkalinity. Ureolysis is catalyzed by the urease enzyme, which is produced by many environmental microorganisms. In the Snake River Plain Aquifer, which is saturated with respect to calcite, any co-precipitated 90Sr should be effectively sequestered over the long-term, even after return to pre-manipulation conditions. Another advantage of the ureolysis approach is that the NH4+ ions produced by the reaction can exchange with cations sorbed to subsurface minerals, thereby enhancing the availability of the radionuclides for re-capture via a more stable mechanism (co-precipitation rather than adsorption).

  20. Larval dispersal underlies demographically important inter-system connectivity in a Great Lakes yellow perch (Perca flavescens) population

    USGS Publications Warehouse

    Brodnik, Reed M.; Fraker, Michael E.; Anderson, Eric J.; Carreon-Martinez, Lucia; DeVanna, Kristen M.; Heath, Dan D.; Reichert, Julie M.; Roseman, Edward F.; Ludsin, Stuart A.

    2016-01-01

    Ability to quantify connectivity among spawning subpopulations and their relative contribution of recruits to the broader population is a critical fisheries management need. By combining microsatellite and age information from larval yellow perch (Perca flavescens) collected in the Lake St. Clair – Detroit River system (SC-DRS) and western Lake Erie with a hydrodynamic backtracking approach, we quantified subpopulation structure, connectivity, and contributions of recruits to the juvenile stage in western Lake Erie during 2006-2007. After finding weak (yet stable) genetic structure between the SC-DRS and two western Lake Erie subpopulations, microsatellites also revealed measurable recruitment of SC-DRS larvae to the juvenile stage in western Lake Erie (17-21% during 2006-2007). Consideration of pre-collection larval dispersal trajectories, using hydrodynamic backtracking, increased estimated contributions to 65% in 2006 and 57% in 2007. Our findings highlight the value of complementing subpopulation discrimination methods with hydrodynamic predictions of larval dispersal by revealing the SC-DRS as a source of recruits to western Lake Erie and also showing that connectivity through larval dispersal can affect the structure and dynamics of large-lake fish populations.

  1. Late-Pleistocene and Holocene remains of Hysterocarpus traski (Tule Perch) from Clear Lake, California, and inferred Holocene temperature fluctuations

    USGS Publications Warehouse

    Casteel, R.W.; Adam, D.P.; Sims, J.D.

    1977-01-01

    The remains of scales of Hysterocarpus traski Gibbons (Tule perch) were found throughout a 27.44-m core from Clear Lake. Most scales occurred between the mud surface and deposits approximately 11,000 years old. Changes in growth rates of the animals were examined by measuring scale annuli and applying an empirically established regression of fish length on scale radius. The data indicate a pattern of accelerating growth rates, reaching a peak between {reversed tilde equals}4000 and 2800 BP. After {reversed tilde equals}2800 BP, growth rates decline markedly. Because the growth rates of these animals are essentially dependent on temperature, the changes observed in the patterns of growth probably reflect changes in climate in the northern Coast Range. The general pattern of inferred temperature increase during the early and middle Holocene, ending between {reversed tilde equals}4000 and 2800 BP, is consistent with evidence from tree-line studies and palynology indicating higher temperatures in parts of the western United States during this period. ?? 1977.

  2. The role of continental shelf width in determining freshwater phylogeographic patterns in south-eastern Australian pygmy perches (Teleostei: Percichthyidae).

    PubMed

    Unmack, Peter J; Hammer, Michael P; Adams, Mark; Johnson, Jerald B; Dowling, Thomas E

    2013-03-01

    Biogeographic patterns displayed by obligate freshwater organisms are intimately related to the nature and extent of connectivity between suitable habitats. Two of the more significant barriers to freshwater connections are seawater and major drainage divides. South-eastern Australia provides a contrast between these barriers as it has discrete areas that are likely influenced to a greater or lesser extent by each barrier type. We use continental shelf width as a proxy for the potential degree of river coalescence during low sea levels. Our specific hypothesis is that the degree of phylogeographic divergence between coastal river basins should correspond to the continental shelf width of each region. This predicts that genetic divergences between river basins should be lowest in regions with a wider continental shelf and that regions with similar continental shelf width should have similar genetic divergences. Pygmy perches (Nannoperca australis and Nannoperca 'flindersi') in south-eastern Australia provide an ideal opportunity to test these biogeographic hypotheses. Phylogeographic patterns were examined based on range-wide sampling of 82 populations for cytochrome b and 23 polymorphic allozyme loci. Our results recovered only limited support for our continental shelf width hypothesis, although patterns within Bass clade were largely congruent with reconstructed low sea-level drainage patterns. In addition, we identified several instances of drainage divide crossings, typically associated with low elevational differences. Our results demonstrate high levels of genetic heterogeneity with important conservation implications, especially for declining populations in the Murray-Darling Basin and a highly restricted disjunct population in Ansons River, Tasmania.

  3. Pesticide residues in Nile tilapia (Oreochromis niloticus) and Nile perch (Lates niloticus) from Southern Lake Victoria, Tanzania.

    PubMed

    Henry, L; Kishimba, M A

    2006-03-01

    Nile tilapia (Oreochromis niloticus) and Nile perch (Lates niloticus) samples were collected from fish landing stations in nine riparian districts on the Tanzanian side of Lake Victoria and screened for residues of 64 organochlorine, organophosphorus, carbamate, and pyrethroid pesticides. The residue levels in the fish fillet were up to 0.003, 0.03 and 0.2 mg/kg fresh weight (0.7, 3.8 and 42 mg/kg lipid weight) of fenitrothion, DDT and endosulfan, respectively. Mean levels within sites were up to 0.002, 0.02 and 0.1 mg/kg fresh weight (0.5, 0.5 and 16 mg/kg lipid weight), respectively. The detection of higher levels of p,p'-DDT than the degradation products (p,p'-DDD and p,p'-DDE), and higher levels of endosulfan isomers (alpha and beta) than the sulphate, in fish samples, implied recent exposure of fish to DDT and endosulfan, respectively. Generally, most of the fish samples had residue levels above the average method detection limits (MDLs), but were within the calculated ADI.

  4. Catchment-Scale Conservation Units Identified for the Threatened Yarra Pygmy Perch (Nannoperca obscura) in Highly Modified River Systems

    PubMed Central

    Brauer, Chris J.; Unmack, Peter J.; Hammer, Michael P.; Adams, Mark; Beheregaray, Luciano B.

    2013-01-01

    Habitat fragmentation caused by human activities alters metapopulation dynamics and decreases biological connectivity through reduced migration and gene flow, leading to lowered levels of population genetic diversity and to local extinctions. The threatened Yarra pygmy perch, Nannoperca obscura, is a poor disperser found in small, isolated populations in wetlands and streams of southeastern Australia. Modifications to natural flow regimes in anthropogenically-impacted river systems have recently reduced the amount of habitat for this species and likely further limited its opportunity to disperse. We employed highly resolving microsatellite DNA markers to assess genetic variation, population structure and the spatial scale that dispersal takes place across the distribution of this freshwater fish and used this information to identify conservation units for management. The levels of genetic variation found for N. obscura are amongst the lowest reported for a fish species (mean heterozygosity of 0.318 and mean allelic richness of 1.92). We identified very strong population genetic structure, nil to little evidence of recent migration among demes and a minimum of 11 units for conservation management, hierarchically nested within four major genetic lineages. A combination of spatial analytical methods revealed hierarchical genetic structure corresponding with catchment boundaries and also demonstrated significant isolation by riverine distance. Our findings have implications for the national recovery plan of this species by demonstrating that N. obscura populations should be managed at a catchment level and highlighting the need to restore habitat and avoid further alteration of the natural hydrology. PMID:24349405

  5. Effect of high pressure processing on textural and microbiological quality of pink perch (Nemipterus japonicus) sausage during chilled storage

    NASA Astrophysics Data System (ADS)

    Kunnath, Sarika; Panda, Satyen Kumar; Jaganath, Bindu; Gudipati, Venkateshwarlu

    2015-10-01

    The non-thermal high pressure (HP) processing was studied on fish sausage to enhance the quality during chilled storage. Pink perch (Nemipterus japonicus) sausages, packed in poly amide casing under vacuum were subjected to 400, 500 and 600 MPa pressures (dwell time: 10 min and ramp rate: 300 MPa/min) and compared with heat-set samples for physico-chemical and microbial quality parameters. Pressurized samples formed softer and glossier gels with a slight reduction in water-holding capacity. HP made the texture of sausage softer, cohesive and less chewy and gummier than heat-treated ones. Folding test seen higher acceptance values in samples treated at 500 and 600 MPa, during storage. Maximum log reduction in microbial count was observed in 600 MPa immediately, and significant difference in cooked and pressurized sausages was seen only up to 7th day. This revealed the potential application of HP in replacing conventional heat treatment for sausages preparation with enhanced shelf-life.

  6. Exploring spatial distributions of larval yellow perch Perca flavescens, bluegill Lepomis macrochirus and their prey in relation to wind.

    PubMed

    Kaemingk, M A; Jolley, J C; Willis, D W; Graeb, B D S

    2011-04-01

    The objectives of the present study were to determine if spatial differences existed between zooplankton, larval yellow perch Perca flavescens and bluegill Lepomis macrochirus (<13 mm total length, L(T)) in Pelican Lake (332 ha), NE, U.S.A. It was hypothesized that wind could act as a transport mechanism for larval fishes in this shallow lake, because strong winds are common at this geographic location. Potential spatial differences were explored, relating to zooplankton densities, size structure and densities of larval P. flavescens and L. macrochirus. Density differences (east v. west side of the lake) were detected for small- (two occasions), medium- (two occasions) and large-sized (one occasion) L. macrochirus larvae. No density differences were detected for small P. flavescens larvae; however, densities of medium- and large-sized P. flavescens were each higher on the west side of the lake on two occasions. There was no evidence that larval P. flavescens and L. macrochirus distributions were related to wind because they were not associated with large wind events. Likewise, large wind event days did not result in any detectable spatial differences of larval P. flavescens and L. macrochirus densities. There appeared to be no spatial mismatch between larval densities and associated prey in the years examined. Thus, wind was not apparently an influential mechanism for zooplankton and larval P. flavescens and L. macrochirus transport within Pelican Lake, and spatial differences in density may instead be related to vegetation and habitat complexities or spawning locations within this shallow lake.

  7. Catchment-scale conservation units identified for the threatened Yarra pygmy perch (Nannoperca obscura) in highly modified river systems.

    PubMed

    Brauer, Chris J; Unmack, Peter J; Hammer, Michael P; Adams, Mark; Beheregaray, Luciano B

    2013-01-01

    Habitat fragmentation caused by human activities alters metapopulation dynamics and decreases biological connectivity through reduced migration and gene flow, leading to lowered levels of population genetic diversity and to local extinctions. The threatened Yarra pygmy perch, Nannoperca obscura, is a poor disperser found in small, isolated populations in wetlands and streams of southeastern Australia. Modifications to natural flow regimes in anthropogenically-impacted river systems have recently reduced the amount of habitat for this species and likely further limited its opportunity to disperse. We employed highly resolving microsatellite DNA markers to assess genetic variation, population structure and the spatial scale that dispersal takes place across the distribution of this freshwater fish and used this information to identify conservation units for management. The levels of genetic variation found for N. obscura are amongst the lowest reported for a fish species (mean heterozygosity of 0.318 and mean allelic richness of 1.92). We identified very strong population genetic structure, nil to little evidence of recent migration among demes and a minimum of 11 units for conservation management, hierarchically nested within four major genetic lineages. A combination of spatial analytical methods revealed hierarchical genetic structure corresponding with catchment boundaries and also demonstrated significant isolation by riverine distance. Our findings have implications for the national recovery plan of this species by demonstrating that N. obscura populations should be managed at a catchment level and highlighting the need to restore habitat and avoid further alteration of the natural hydrology.

  8. {sup 32}P-postlabeling analysis of DNA adducts in wild perch (Perca fluviatilis) and northern pike (Esox lucius)

    SciTech Connect

    Ericson, G.; Liewenborg, B.; Balk, L.

    1995-12-31

    Several previous studies have demonstrated a correlation between high concentrations of sediment-associated contaminants and elevated levels of aromatic/hydrophobic DNA adduct levels in the liver of benthic fish species. In the present study DNA adducts was analyzed in coastal populations of perch (Perca fluviatilis) and northern pike (Esox lucius). Fish were sampled from four different sites in a gradient from a heavily industrialized area at the Swedish Baltic coast. For comparison, fish were also caught in a reference area with no main industries and comparatively low levels of contaminants of anthropogenic origin. DNA was extracted from liver and several extrahepatic tissues and DNA adducts were analyzed by the nuclease PI version of the {sup 32}P-postlabeling assay. The autoradiograms derived from DNA of fish from the contaminated sites showed several adduct spots not visible on the autoradiograms derived from fish from the reference area. Total adduct levels were significantly elevated in several tissues in fish from contaminated sites compared to the reference area. Species and tissue-specific differences in adduct levels and the use of {sup 32}P-postlabeling analysis of DNA adducts as a biomarker to monitor the presence and effects of genotoxic chemicals in the aquatic environment are discussed.

  9. Ocean optics

    SciTech Connect

    Spinard, R.W.; Carder, K.L.; Perry, M.J.

    1994-12-31

    This volume is the twenty fifth in the series of Oxford Monographs in Geology and Geophysics. The propagation off light in the hydra-atmosphere systems is governed by the integral-differential Radiative Transfer Equation (RTE). Closure and inversion are the most common techniques in optical oceanography to understand the most basic principles of natural variability. Three types of closure are dealt with: scale closure, experimental closure, and instrument closure. The subject is well introduced by Spinard et al. in the Preface while Howard Gordon in Chapter 1 provides an in-depth introduction to the RTE and its inherent problems. Inherent and apparent optical properties are dealt with in Chapter 2 by John Kirk and the realities of optical closure are presented in the following chapter by Ronald Zaneveld. The balance of the papers in this volume is quite varied. The early papers deal in a very mathematical manner with the basics of radiative transfer and the relationship between inherent and optical properties. Polarization of sea water is discussed in a chapter that contains a chronological listing of discoveries in polarization, starting at about 1000 AD with the discovery of dichroic properties of crystals by the Vikings and ending with the demonstration of polarotaxis in certain marine organisms by Waterman in 1972. Chapter 12 on Raman scattering in pure water and the pattern recognition techniques presented in Chapter 13 on the optical effects of large particles may be of relevance to fields outside ocean optics.

  10. Tidally discontinuous ocean forcing in bar-built estuaries: The interaction of tides, infragravity motions, and frictional control

    NASA Astrophysics Data System (ADS)

    Williams, M. E.; Stacey, M. T.

    2016-01-01

    Shallow, bar-built estuaries on wave-dominated coasts in Mediterranean climates experience an intermittent connection to the ocean. In the presence of low streamflow, their inlets may completely close as a result of nearshore sand transport, but even in the open condition, these inlets remain constricted. Extensive field measurements in the highly salt-stratified Pescadero estuary in northern California show that the shallow mouth causes these estuaries to experience discontinuous tidal forcing. While the ocean and estuary are fully connected with near-equal water levels, tidal velocities are slow but infragravity motions in the nearshore induce large velocity oscillations within the estuary. As the ocean tide falls, infragravity forcing is cut off, because the estuarine mouth is perched above the low tide ocean water level, and ebbing velocities are set by bed friction. Observations reveal this oscillation between ocean-forced and frictionally controlled conditions characterizes and sets estuarine hydrodynamics. Additional wave setup of the lagoon emphasizes the dependence of these estuaries on nearshore ocean conditions, but the diurnal or semidiurnal retreat of the ocean below the mouth cuts off this nearshore influence so it too is tidally varying. Here we present detailed observations and a framework for understanding hydrodynamics in small, shallow bar-built estuaries.

  11. Perched Lava Pond Complex on South Rift of Axial Volcano Revealed in AUV Mapping

    NASA Astrophysics Data System (ADS)

    Paduan, J. B.; Clague, D. A.; Caress, D. W.; Thomas, H. J.

    2013-12-01

    -like structures and jumbled sheet flows on the floors suggest the eruption was on-going when the ponds emptied. 14C-dating of foraminifera from basal sediments on the pond floors gives a minimum age for the ponds of ~1500 years, which is older than any of the surface flows in Axial's summit caldera. Limu o Pele was abundant. Glass contents of the recovered lavas are 7.6 to 8.0 wt% MgO with few exceptions, and other than being plagioclase-phyric, the chemistry is similar to the majority of lavas at the summit. Lava samples from the floors of several ponds have a few tenths of a weight percent lower MgO than the nearby levees, suggesting the pond's molten interior or resupplied lavas had some time to cool. The varying levee rim heights and abundance of ponds in the vicinity suggest this type of activity occurred many times in this area, but it is an unusual eruption style for mid-ocean ridges. Another lava pond complex with even higher levees occurs on the north rift of Axial Volcano. Formation of these ponds requires long-lived, steady, moderate-eruption-rate lava effusion on nearly horizontal seafloor and may occur only on deep distal rift zones of central volcanoes.

  12. Feeding Glycyrrhiza glabra (liquorice) and Astragalus membranaceus (AM) alters innate immune and physiological responses in yellow perch (Perca flavescens).

    PubMed

    Elabd, Hiam; Wang, Han-Ping; Shaheen, Adel; Yao, Hong; Abbass, Amany

    2016-07-01

    The current work assessed the potential immunomodulatory and growth-promoting effects of Astragalus membranaceus (AM) and Glycyrrhiza glabra (liquorice) in Yellow perch (Perca flavescens). In this regard, fish with an average weight of 31 ± 1.0 g were divided into five groups, and fed daily with an additive-free basal diet (control); 1, 2, and 3% (w/w) Glycyrrhiza glabra, and the fifth diet was incorporated with a combination of 1% G. glabra-AM for a four-week period. Immunological, biochemical and growth parameters were measured; and sub-groups of fish were exposed to 1-week starvation. The results showed that incorporating AM and liquorice in the diet significantly improved Immunological [superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), Lipid peroxidase (LPx) and lysozyme activities], biochemical [Aspartate Aminotransferase (AST) and Alanine Transaminase (ALT) activities; and glucose and cortisol concentrations] and growth performance parameters [body mass gain (BMG), specific growth rate (SGR), length, condition factor (K) and feed conversion ratio (FCR)]. In addition, markedly up-regulated the expression of related genes [Insulin-Like Growth Factor-1 (IGF-1), Serum amyloid A (SAA), Complement Component C3 (CCC3), Alpha 2 Macroglobulin (A2M), SOD and GPx] in treated fish groups compared to the control. Conclusively, feeding AM and liquorice diets significantly increased (P < 0.05) growth performance, antioxidant and immune response profiles throughout the entire experiment, suggesting their beneficial rule as natural anti-stress agents. Copyright © 2016. Published by Elsevier Ltd.

  13. Corticosteroids deeply depress the in vitro steroidogenic capacity of Eurasian perch ovary at the end of the reproductive cycle.

    PubMed

    Mandiki, S N M; Milla, S; Robles, S Nkogo; Kestemont, P

    2017-02-07

    Corticosteroids play positive or negative role in the reproductive mechanisms of many fish species but the physiological contexts relating to such biphasic actions are not well defined. In the present study we investigated to what extent corticosteroids (cortisol-Co, 11-deoxycorticosterone-DOC) hormones may interfere with the steroidogenic capacity of Eurasian perch ovarian tissues, and we tested whether the negative effects of corticosteroids may be mitigated by potential stimulating endocrine factors, namely insulin-like growth factor-1 (IGF), human chorionic gonadotropin (HCG) or thyroid hormones (Triidothyronine-T3, thyroxine-T4). Ovarian tissues from six maturing fish at late vitellogenesis developmental stage (LVO) or at the start of the final meiotic oocyte maturation (FMO) were incubated during 6h in Cortland medium containing various endocrine compounds. Both corticosteroids drastically suppressed aromatase activity (AA) and sex-steroid production, namely 17-β estradiol (E2), 17α-20β-dihydroxy-4-pregnen-3-one (DHP) and testosterone (T). HCG significantly prevented the suppression of both AA and sex-steroid production by low and high cortisol doses, but a lesser AA protection was observed in the case of DOC. The protection of DHP and T productions by HCG from the negative effects by the two corticosteroids was higher at FMO than at LVO stage. IGF or thyroid hormone treatments were lesser effective or ineffective in mitigating the suppression of AA or sex-steroid production by cortisol. The results suggest that an increase in cortisol or DOC such as after mild or high stress intensity may inhibit drastically the ovarian steroidogenic capacity whatever the final oocyte maturation stage in percid fish by hampering AA and sex-steroid production. That inhibition may be partly mitigated by gonadotropins but not IGF nor thyroid hormones, especially at final meiotic oocyte maturation stage.

  14. Perching and Interflow Occurrence over a Shallow Argillic Layer in a Low Relief Upper Coastal Plan Watershed

    NASA Astrophysics Data System (ADS)

    Du, E.; Jackson, C. R.; Vache, K. B.; Hopp, L.

    2011-12-01

    On a first order, low relief, forested watershed at the Savannah River Site (SRS) in the Upper Coastal Plain of South Carolina, we are monitoring soil moisture, shallow piezometric behavior, interflow, groundwater dynamics, and streamflow to identify critical flow pathways, characterize system behavior, and parameterize distributed hydrologic models for estimating effects of bioenergy feedstock production. A mix of pine and hardwoods reforested from agricultural land abandoned in 1950 cover the watershed. Sandy topsoils overlie a low permeability sandy clay loam argillic layer on gently rolling hills with flat forested wetland valleys accommodating slow moving intermittent streamflow. Depths to clay and the saturated hydraulic conductivity (Ksat) of the clay are highly variable. Compact constant head permeameter measurements vary over six orders of magnitude, with anomalies featuring conductivities greater than those observed in the topsoils. Perching on the clay horizon was common. Although the geometric mean and median Ksat of the argillic layer are low (Ksat as low as 0.001 cm/hr), interflow only occurs with large storms on wet soils apparently due to clay anomalies, low relief topography, and relatively high active storage within the topsoil. Fine scale detection of depth to clay (2 by 1m) implies that delineation of subsurface topography may help to understand the flow behavior and destination. Wells records and saturated valley survey show that streamflow dynamics is poorly related to interflow but mainly controlled by seasonal groundwater dynamics. Streamflow analyses at different scales indicate hyporheic flow contribute significantly to the overall water budget at 1st order streams while the groundwater bypass is relatively small at downstream gauges. The next step is to integrate temporal series data of streamflow, soil moisture, groundwater, and interflow to develop and parameterized hydrologic models.

  15. Environmental safety level of lead (Pb) pertaining to toxic effects on grey mullet (Mugil cephalus) and tiger perch (Terapon jarbua).

    PubMed

    Hariharan, G; Purvaja, R; Ramesh, R

    2016-01-01

    Acute and chronic bioassay toxicity test of Lead (Pb) in Grey Mullet (Mugil cephalus), and Tiger perch (Terapon jarbua) was conducted. LC50 values (Lethal Concentration) from acute tests and chronic values were calculated by the geometric mean of the No-Observed-Effect Concentration (NOEC) and the Lowest-Observed-Effect Concentration (LOEC) in a study period of 30 days. This research was conducted to evaluate the quantitative relationship between toxicity test statistics and correlation between toxicant and the organisms exposed. Three test average LC50 was analyzed for 24, 48, 72, and 96 h and the 96 h average LC50 of M. cephalus and T. jarbua is 2.57 ± 0.47 and 2.99 ± 0.23 mg/L of Pb, respectively. Significant correlation is observed with the increased time duration and exposure concentration. The NOEC and LOEC values were calculated based on survival of test organisms for M. cephalus and T. jarbua and the values are 0.014 and 0.029 and 0.011 and 0.022 mg/L, respectively. The chronic value is found to be 0.011 mg/L for M. cephalus and 0.021 mg/L for T. jarbua. The intensity of biochemical and histological alterations increased gradually with increased Pb concentration and the exposure time. Toxicity testing is the primary step to determine the water quality safe limit on marine organisms. The outcome of the study indicates that the sensitivity of juvenile organisms to Pb, persistence of toxic effects and biomarkers as a tool capable of revealing the toxic effects of heavy metals on the environment and aquatic biota.

  16. Daily rhythmicity of clock gene transcript levels in fast and slow muscle fibers from Chinese perch (Siniperca chuatsi).

    PubMed

    Wu, Ping; Li, Yu-Long; Cheng, Jia; Chen, Lin; Zhu, Xin; Feng, Zhi-Guo; Zhang, Jian-She; Chu, Wu-Ying

    2016-12-08

    Clock genes are considered to be the molecular core of biological clock in vertebrates and they are directly involved in the regulation of daily rhythms in vertebrate tissues such as skeletal muscles. Fish myotomes are composed of anatomically segregated fast and slow muscle fibers that possess different metabolic and contractile properties. To date, there is no report on the characterization of the circadian clock system components of slow muscles in fish. In the present study, the molecular clock components (clock, arntl1/2, cry1/2/3, cry-dash, npas2, nr1d1/2, per1/2/3, rorα and tim genes) and their daily transcription levels were characterized in slow and fast muscles of Chinese perch (Siniperca chuatsi). Among the 15 clock genes, nrld2 and per3 had no daily rhythmicity in slow muscles, and cry2/3 and tim displayed no daily rhythmicity in fast muscles of the adult fish. In the slow muscles, the highest expression of the most clock paralogs occurred at the dark period except arntl1, nr1d1, nr1d2 and tim. With the exception of nr1d2 and tim, the other clock genes had an acrophase at the light period in fast muscles. The circadian expression of the myogenic regulatory factors (mrf4 and myf5), mstn and pnca showed either a positive or a negative correlation with the transcription pattern of the clock genes in both types of muscles. It was the first report to unravel the molecular clock components of the slow and fast muscles in vertebrates. The expressional pattern differences of the clock genes between the two types of muscle fibers suggest that the clock system may play key roles on muscle type-specific tissue maintenance and function.

  17. Evaluating fishery rehabilitation under uncertainty: A bioeconomic analysis of quota management for the Green Bay yellow perch fishery

    USGS Publications Warehouse

    Johnson, B.L.; Milliman, S.R.; Bishop, R.C.; Kitchell, J.F.

    1992-01-01

    The fishery for yellow perch Perca flavescens in Green Bay, Lake Michigan, is currently operating under a rehabilitation plan based on a commercial harvest quota. We developed a bioeconomic computer model that included links between population density and growth, recruitment, and fishing effort for this fishery. Random variability was included in the stock-recruitment relation and in a simulated population assessment. We used the model in an adaptive management framework to evaluate the effects of the rehabilitation plan on both commercial and sport fisheries and to search for ways to improve the plan. Results indicate that the current quota policy is a member of a set of policies that would meet most management goals and increase total value of the fishery. Sensitivity analyses indicate that this conclusion is robust over a wide range of biological conditions. We predict that commercial fishers will lose money relative to the baseline condition, but they may receive other benefits from the elimination of the common-property nature of the fishery. The prospect exists for managing variability in harvest and stock size and for maximizing economic returns in the fishery, but more information is required, primarily on sportfishing effort dynamics and angler preferences. Stock-recruitment relations, density dependence of growth, and dynamics of sportfishing effort are the primary sources of uncertainty limiting the precision of our predictions. The current quota policy is about as good as other policies at reducing this uncertainty and appears, overall, to be one of the best choices for this fishery. The analytical techniques used in this study were primarily simple, heuristic approaches that could be easily transferred to other studies.

  18. Studying ocean acidification in the Arctic Ocean

    USGS Publications Warehouse

    Robbins, Lisa

    2012-01-01

    The U.S. Geological Survey (USGS) partnership with the U.S. Coast Guard Ice Breaker Healey and its United Nations Convention Law of the Sea (UNCLOS) cruises has produced new synoptic data from samples collected in the Arctic Ocean and insights into the patterns and extent of ocean acidification. This framework of foundational geochemical information will help inform our understanding of potential risks to Arctic resources due to ocean acidification.

  19. Ocean Commissions: Ocean Policy Review and Outlook

    DTIC Science & Technology

    2005-05-05

    favorably of its recommendations.12 Articles and editorials in regional media generally focused on selected issues of local relevance,13 and interest...of Texas posted at [http://www.governor.state.tx.us/divisions/ bpp /files/ ocean_policy.pdf], visited on July 7, 2004. 16 For example, see [http...Broaden ocean education and awareness through a commitment to teach and learn about our oceans, at all levels of society. Comments on the Pew Commission’s

  20. Comparative susceptibility among three stocks of yellow perch, Perca flavescens (Mitchill), to viral haemorrhagic septicaemia virus strain IVb from the Great Lakes

    USGS Publications Warehouse

    Olson, W.; Emmenegger, E.; Glenn, J.; Winton, J.; Goetz, F.

    2013-01-01

    The Great Lakes strain of viral haemorrhagic septicaemia virus IVb (VHSV-IVb) is capable of infecting a wide number of naive species and has been associated with large fish kills in the Midwestern United States since its discovery in 2005. The yellow perch, Perca flavescens (Mitchill), a freshwater species commonly found throughout inland waters of the United States and prized for its high value in sport and commercial fisheries, is a species documented in several fish kills affiliated with VHS. In the present study, differences in survival after infection with VHSV IVb were observed among juvenile fish from three yellow perch broodstocks that were originally derived from distinct wild populations, suggesting innate differences in susceptibility due to genetic variance. While all three stocks were susceptible upon waterborne exposure to VHS virus infection, fish derived from the Midwest (Lake Winnebago, WI) showed significantly lower cumulative % survival compared with two perch stocks derived from the East Coast (Perquimans River, NC and Choptank River, MD) of the United States. However, despite differences in apparent susceptibility, clinical signs did not vary between stocks and included moderate-to-severe haemorrhages at the pelvic and pectoral fin bases and exophthalmia. After the 28-day challenge was complete, VHS virus was analysed in subsets of whole fish that had either survived or succumbed to the infection using both plaque assay and quantitative PCR methodologies. A direct correlation was identified between the two methods, suggesting the potential for both methods to be used to detect virus in a research setting.

  1. Genome-wide data delimits multiple climate-determined species ranges in a widespread Australian fish, the golden perch (Macquaria ambigua).

    PubMed

    Beheregaray, Luciano B; Pfeiffer, Lauren V; Attard, Catherine R M; Sandoval-Castillo, Jonathan; Domingos, Fabricius M C B; Faulks, Leanne K; Gilligan, Dean M; Unmack, Peter J

    2017-06-01

    Species range limits often fluctuate in space and time in response to variation in environmental factors and to gradual niche evolution due to changes in adaptive traits. We used genome-wide data to investigate evolutionary divergence and species range limits in a generalist and highly dispersive fish species that shows an unusually wide distribution across arid and semi-arid regions of Australia. We generated ddRAD data (18,979 filtered SNPs and 1.725million bp of sequences) for samples from 27 localities spanning the native range of golden perch, Macquaria ambigua (Teleostei; Percichthyidae). Our analytical framework uses population genomics to assess connectivity and population structure using model-based and model-free approaches, phylogenetics to clarify evolutionary relationships, and a coalescent-based Bayesian species delimitation method to assess statistical support of inferred species boundaries. Addressing uncertainties regarding range limits and taxonomy is particularly relevant for this iconic Australian species because of the intensive stocking activities undertaken to support its recreational fishery and its predicted range shifts associated with ongoing climate change. Strong population genomic, phylogenetic, and coalescent species delimitation support was obtained for three separately evolving metapopulation lineages, each lineage should be considered a distinct cryptic species of golden perch. Their range limits match the climate-determined boundaries of main river basins, despite the ability of golden perch to cross drainage divides. We also identified cases suggestive of anthropogenic hybridization between lineages due to stocking of this recreationally important fish, as well as a potential hybrid zone with a temporally stable pattern of admixture. Our work informs on the consequences of aridification in the evolution of aquatic organisms, a topic poorly represented in the literature. It also shows that genome-scale data can substantially

  2. Histopathology of brown bullhead (Ameiurus nebulosus), smallmouth bass (Micropterus dolomieu), and yellow perch (Perca flavescens) in relation to polychlorinated biphenyl (PCB) contamination in the Hudson River.

    PubMed

    Pinkney, Alfred E; Myers, Mark S; Rutter, Michael A

    2017-01-01

    From the 1940s through 1977, at least 590,000kg of polychlorinated biphenyls (PCBs) were released into the Hudson River from General Electric manufacturing plants located in Hudson Falls and Fort Edward, New York. In 1984, the U.S. Environmental Protection Agency designated a nearly 322km reach as the Hudson River PCBs Superfund Site. Here we describe a Fish Health Assessment study, part of a Natural Resource Damage Assessment, that evaluated the prevalence of toxicopathic lesions in adult brown bullhead (Ameiurus nebulosus), smallmouth bass (Micropterus dolomieu), and yellow perch (Perca flavescens). In fall 2001, 29-51 fish of each species were collected in fall 2001 from highly contaminated areas below the plants (Thompson Island Pool (TIP) and Stillwater Dam Pool (STW)), an upriver reference area (Feeder Dam Pool (FDP)), and a reference lake, Oneida Lake (ODA). The focus was on histopathologic lesions and observations associated with contaminant exposure: liver-neoplasms, foci of cellular alteration, bile duct hyperplasia; testes-ovotestis (testicular oocytes), germ cell degeneration, altered developmental stage; ovaries-atresia and altered developmental stage. Lesions associated with PCB exposure were defined as those with significantly greater prevalence and/or severity in TIP and STW compared with ODA and FDP. For brown bullhead and smallmouth bass, no lesions or changes in gonadal development met those criteria. In yellow perch, ovarian atresia was the only lesion associated with PCB exposure. Prevalence was 53% in FDP, 75% in ODA, and 100% in both STW and TIP; severity increased from mostly minimal to mild-moderate. Because of the high prevalence of atresia in reference collections, it is likely that factors other than PCBs are also involved. As part of a post-dredging monitoring plan, we recommend assessing gonad structure and function in yellow perch collected at the time of spawning in locations with a range of PCB contamination.

  3. A multi-level biological approach to evaluate impacts of a major municipal effluent in wild St. Lawrence River yellow perch (Perca flavescens).

    PubMed

    Houde, Magali; Giraudo, Maeva; Douville, Mélanie; Bougas, Bérénice; Couture, Patrice; De Silva, Amila O; Spencer, Christine; Lair, Stéphane; Verreault, Jonathan; Bernatchez, Louis; Gagnon, Christian

    2014-11-01

    The development of integrated ecotoxicological approaches is of great interest in the investigation of global concerns such as impacts of municipal wastewater effluents on aquatic ecosystems. The objective of this study was to investigate the effects of a major wastewater municipal effluent on fish using a multi-level biological approach, from gene transcription and enzyme activities to histological changes. Yellow perch (Perca flavescens) were selected based on their wide distribution, their commercial and recreational importance, and the availability of a customized microarray. Yellow perch were sampled upstream of a major municipal wastewater treatment plant (WWTP) and 4 km and 10 km downstream from its point of discharge in the St. Lawrence River (Quebec, Canada). Concentrations of perfluoroalkyl substances (PFASs), polybrominated diphenyl ethers (PBDEs) and metals/trace elements in whole body homogenates were comparable to those from other industrialized regions of the world. Genomic results indicated that the transcription level of 177 genes was significantly different (p<0.024) between exposed and non-exposed fish. Among these genes, 38 were found to be differentially transcribed at both downstream sites. Impacted genes were associated with biological processes and molecular functions such as immunity, detoxification, lipid metabolism/energy homeostasis (e.g., peroxisome proliferation), and retinol metabolism suggesting impact of WWTP on these systems. Moreover, antioxidant enzyme activities were more elevated in perch collected at the 4 km site. Biomarkers of lipid metabolism, biosynthetic activity, and aerobic capacities were significantly lower (p<0.05) in fish residing near the outfall of the effluent. Histological examination of the liver indicated no differences between sites. Correlations between PFAS, PBDE, and metal/trace element tissue concentrations and markers of peroxisomal proliferation, oxidative stress, and retinoid metabolism were found at

  4. Response of oxidative stress transcripts in the brain of wild yellow perch (Perca flavescens) exposed to an environmental gradient of methylmercury.

    PubMed

    Graves, Stephanie D; Kidd, Karen A; Batchelar, Katharina L; Cowie, Andrew M; O'Driscoll, Nelson J; Martyniuk, Christopher J

    2017-02-01

    Methylmercury (MeHg) exposure and adverse health effects in fishes have been documented, but the molecular mechanisms involved in toxicity have not been fully characterized. The objectives of the current study were to (1) determine whether total Hg (THg) in the muscle was predictive of MeHg concentrations in the brain of wild female yellow perch (Perca flavescens) collected from four lakes in Kejimkujik National Park, a known biological mercury (Hg) hotspot in Nova Scotia, Canada and (2) to determine whether transcripts involved in the oxidative stress response were altered in abundance in fish collected across five lakes representing a MeHg gradient. In female yellow perch, MeHg in whole brain (0.38 to 2.00μg/g wet weight) was positively associated with THg in muscle (0.18 to 2.13μg/g wet weight) (R(2)=0.61, p<0.01), suggesting that muscle THg may be useful for predicting MeHg concentrations in the brain. Catalase (cat) mRNA levels were significantly lower in brains of perch collected from lakes with high Hg when compared to those individuals from lakes with relatively lower Hg (p=0.02). Other transcripts (cytochrome c oxidase, glutathione peroxidase, glutathione-s-transferase, heat shock protein 70, protein disulfide isomerase, and superoxide dismutase) did not show differential expression in the brain over the gradient. These findings suggest that MeHg may be inversely associated with catalase mRNA abundance in the central nervous system of wild fishes.

  5. Effects of moist litter, perches, and droppings pit on fluctuating asymmetry, tonic immobility duration, and heterophil-to-lymphocyte ratio of laying hens.

    PubMed

    Campo, J L; Prieto, M T

    2009-04-01

    The purpose of this study was to analyze the effects of moist litter, perches, and droppings pit on the fluctuating asymmetry, the tonic immobility duration, and the heterophil:lymphocyte ratio of laying hens. In experiment 1, hens from 4 Spanish breeds and a White Leghorn population, that had been housed in moist or dry litter pens from 20 wk of age, were used. Treatment effect was significant for the fluctuating asymmetry of toe length (P < 0.05), the fluctuating asymmetry of hens housed in moist litter pens being larger. The duration of tonic immobility was significantly longer (P < 0.01) in hens housed in moist litter pens. Thus, litter moisture is associated with the well-being or fear levels of hens, as indicated by the fluctuating asymmetry and the tonic immobility duration. In experiment 2, hens from the Black Menorca breed, that had been housed in pens with or without perches from 20 wk of age, were used. The fluctuating asymmetry of wattle length and the combined fluctuating asymmetry were significantly greater (P < 0.001) in hens housed in pens without perches. Thus, the presence of perches is associated with the well-being level of birds, as indicated by the fluctuating asymmetry. In experiment 3, hens from 4 Spanish breeds and a White Leghorn population, that had been housed in pens with or without a droppings pit, were used. There was significant difference for the fluctuating asymmetry of leg length (P < 0.001) between hens housed in pens with or without a droppings pit, the fluctuating asymmetry of hens housed in pens without a droppings pit being larger. There were no significant differences for the duration of tonic immobility and the heterophil:lymphocyte ratio between both treatments. Thus, the presence of a droppings pit is associated with the well-being of hens, as indicated by the fluctuating asymmetry, and does not contribute to their fear or stress levels, as indicated by the tonic immobility duration and the heterophil:lymphocyte ratio.

  6. An update of hydrologic conditions and distribution of selected constituents in water, Snake River Plain aquifer and perched groundwater zones, Idaho National Laboratory, Idaho, emphasis 2006-08

    USGS Publications Warehouse

    Davis, Linda C.

    2010-01-01

    Since 1952, radiochemical and chemical wastewater discharged to infiltration ponds (also called percolation ponds), evaporation ponds, and disposal wells at the Idaho National Laboratory (INL) has affected water quality in the eastern Snake River Plain aquifer and perched groundwater zones underlying the INL. The U.S. Geological Survey, in cooperation with the U.S. Department of Energy, maintains groundwater monitoring networks at the INL to determine hydrologic trends, and to delineate the movement of radiochemical and chemical wastes in the aquifer and in perched groundwater zones. This report presents an analysis of water-level and water-quality data collected from aquifer and perched groundwater wells in the USGS groundwater monitoring networks during 2006-08. Water in the Snake River Plain aquifer primarily moves through fractures and interflow zones in basalt, generally flows southwestward, and eventually discharges at springs along the Snake River. The aquifer primarily is recharged from infiltration of irrigation water, infiltration of streamflow, groundwater inflow from adjoining mountain drainage basins, and infiltration of precipitation. From March-May 2005 to March-May 2008, water levels in wells generally remained constant or rose slightly in the southwestern corner of the INL. Water levels declined in the central and northern parts of the INL. The declines ranged from about 1 to 3 feet in the central part of the INL, to as much as 9 feet in the northern part of the INL. Water levels in perched groundwater wells around the Advanced Test Reactor Complex (ATRC) also declined. Detectable concentrations of radiochemical constituents in water samples from wells in the Snake River Plain aquifer at the INL generally decreased or remained constant during 2006-08. Decreases in concentrations were attributed to decreased rates of radioactive-waste disposal, radioactive decay, changes in waste-disposal methods, and dilution from recharge and underflow. In April

  7. A comparative study on the parasite fauna of perch, Perca fluviatilis L., collected from a freshwater coastal lake, brackish-water Baltic Sea, and the interconnecting canal.

    PubMed

    Wierzbicka, Jadwiga; Wierzbicki, Krystyn; Piasecki, Wojciech; Smietana, Przemysław

    2005-01-01

    Parasitological surveys of freshwater fishes rarely include comparisons between two ecologically different bodies of water. Such studies might help to understand processes of establishment of parasite faunas in estuary areas. The results obtained could also provide useful tools for discriminating various fish populations based on the composition of their parasite faunas. The present authors attempted to study such data from Resko Lake-a freshwater coastal lagoon (6 km2 surface area), and the adjacent areas of the Baltic Sea. Resko Lake, located 12 km west of the city of Kołobrzeg, is shallow (1.5 m) and is connected to the sea through a small canal (1.3 km long, 30 m wide). The material was collected from April 1969 and July 1970. A total of 159 perch were collected, in this number 104 fish from the lake, 43 from the sea, and 12 from the canal. A total of 32 parasite species were recovered from the fish necropsied. The parasites represented 7 higher taxa: Protozoa (3 species), Cestoda (4), Digenea (13), Nematoda (5), Acanthocephala (3), Mollusca (1), and Crustacea (3). The parasite fauna of perch from the sea was definitely more abundant (31 species) compared to that of the lake (21), and the canal (12 species). Infection parameters of 13 parasite species demonstrated significant differences between the locations studied. The infection level of 6 parasite species was significantly higher in perch from the sea: Bothriocephalus scorpii, Ligula sp., Brachyphallus crenatus, Camallanus truncatus, Hysterothylacium aduncum, and Echinorhynchus gadi. On the other hand, infection levels of 7 other species were higher at the lake: Triaenophorus nodulosus, Bucephalus polymorphus, Azygia lucii, Tylodelphys clavata, Camallanus lacustris, Acanthocephalus lucii, and Achtheres percarum. The infection parameters of the fish from canal were similar to those from the lake. Interesting observations were made on the seasonality of certain parasites of both lake- and Baltic perch. The

  8. The Ocean Literacy Campaign

    NASA Astrophysics Data System (ADS)

    Schoedinger, S. E.; Strang, C.

    2008-12-01

    "Ocean Literacy is an understanding of the ocean's influence on you and your influence on the ocean." This simple statement captures the spirit of a conceptual framework supporting ocean literacy (COSEE et al., 2005). The framework comprises 7 essential principles and 44 fundamental concepts an ocean literate person would know (COSEE et al., 2005). The framework is the result of an extensive grassroots effort to reach consensus on (1) a definition for ocean literacy and (2) an articulation of the most important concepts to be understood by ocean-literate citizen (Cava et al., 2005). In the process of reaching consensus on these "big ideas" about the ocean, what began as a series of workshops has emerged as a campaign "owned" by an ever-expanding community of individuals, organizations and networks involved in developing and promoting the framework. The Ocean Literacy Framework has provided a common language for scientists and educators working together and serves as key guidance for the ocean science education efforts. This presentation will focus on the impact this Ocean Literacy Campaign has had to date as well as efforts underway to provide additional tools to enable educators and educational policy makers to further integrate teaching and learning about the ocean and our coasts into formal K-12 education and informal education. COSEE, National Geographic Society, NOAA, College of Exploration (2005). Ocean Literacy: The Essential Principles of Ocean Sciences Grades K-12, a jointly published brochure, URL: http://www.coexploration.org/oceanliteracy/documents/OceanLitChart.pdf Cava, F., S. Schoedinger , C. Strang, and P. Tuddenham (2005). Science Content and Standards for Ocean Literacy: A Report on Ocean Literacy, URL: http://www.coexploration.org/oceanliteracy/documents/OLit2004-05_Final_Report.pdf.

  9. An update of hydrologic conditions and distribution of selected constituents in water, eastern Snake River Plain aquifer and perched groundwater zones, Idaho National Laboratory, Idaho, emphasis 2012-15

    USGS Publications Warehouse

    Bartholomay, Roy C.; Maimer, Neil V.; Rattray, Gordon W.; Fisher, Jason C.

    2017-04-10

    Since 1952, wastewater discharged to in ltration ponds (also called percolation ponds) and disposal wells at the Idaho National Laboratory (INL) has affected water quality in the eastern Snake River Plain (ESRP) aquifer and perched groundwater zones underlying the INL. The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Energy, maintains groundwater-monitoring networks at the INL to determine hydrologic trends and to delineate the movement of radiochemical and chemical wastes in the aquifer and in perched groundwater zones. This report presents an analysis of water-level and water-quality data collected from the ESRP aquifer, multilevel monitoring system (MLMS) wells in the ESRP aquifer, and perched groundwater wells in the USGS groundwater monitoring networks during 2012-15.

  10. Harvesting the Ocean: 1. The Ocean.

    ERIC Educational Resources Information Center

    Caton, Albert, Ed.; And Others

    This booklet is the first in a series of three interdisciplinary units which focus specifically on the Pacific Ocean and its surrounding countries. The booklet, designed for lower secondary students, provides an introduction to the ocean environment such that students can understand the physical factors underlying issues raised by the other two…

  11. Harvesting the Ocean: 1. The Ocean.

    ERIC Educational Resources Information Center

    Caton, Albert, Ed.; And Others

    This booklet is the first in a series of three interdisciplinary units which focus specifically on the Pacific Ocean and its surrounding countries. The booklet, designed for lower secondary students, provides an introduction to the ocean environment such that students can understand the physical factors underlying issues raised by the other two…

  12. Ocean Robotic Networks

    SciTech Connect

    Schofield, Oscar

    2012-05-23

    We live on an ocean planet which is central to regulating the Earth’s climate and human society. Despite the importance of understanding the processes operating in the ocean, it remains chronically undersampled due to the harsh operating conditions. This is problematic given the limited long term information available about how the ocean is changing. The changes include rising sea level, declining sea ice, ocean acidification, and the decline of mega fauna. While the changes are daunting, oceanography is in the midst of a technical revolution with the expansion of numerical modeling techniques, combined with ocean robotics. Operating together, these systems represent a new generation of ocean observatories. I will review the evolution of these ocean observatories and provide a few case examples of the science that they enable, spanning from the waters offshore New Jersey to the remote waters of the Southern Ocean.

  13. Ethane ocean on Titan

    NASA Technical Reports Server (NTRS)

    Lunine, J. I.; Stevenson, D. J.; Yung, Y.L.

    1983-01-01

    Voyager I radio occultation data is employed to develop a qualitative model of an ethane ocean on Titan. It is suggested that the ocean contains 25 percent CH4 and that the ocean is in dynamic equilibrium with an N2 atmosphere. Previous models of a CH4 ocean are discounted due to photolysis rates of CH4 gas. Tidal damping of Titan's orbital eccentricity is taken as evidence for an ocean layer approximately 1 km deep, with the ocean floor being covered with a solid C2H2 layer 100 to 200 m thick. The photolytic process disrupting the CH4, if the estimates of the oceanic content of CH4 are correct, could continue for at least one billion years. Verification of the model is dependent on detecting CH4 clouds in the lower atmosphere, finding C2H6 saturation in the lower troposphere, or obtaining evidence of a global ocean.

  14. Introduction to ocean optics

    NASA Technical Reports Server (NTRS)

    Gordon, H. R.; Smith, R. C.; Zaneveld, J. R. V.

    1980-01-01

    The fundamental inherent and apparent optical properties of natural waves are reviewed and relationships between these properties, as related through the radiative transfer equation, are examined. Applications of ocean optics to geophysics, biological oceanography, and ocean remote sensing are discussed.

  15. People and Oceans.

    ERIC Educational Resources Information Center

    NatureScope, 1988

    1988-01-01

    Discusses people's relationship with oceans, focusing on ocean pollution, use, and protective measures of the sea and its wildlife. Activities included are "Mythical Monsters"; "Globetrotters"; "Plastic in the Sea"; and "Sea of Many Uses." (RT)

  16. People and Oceans.

    ERIC Educational Resources Information Center

    NatureScope, 1988

    1988-01-01

    Discusses people's relationship with oceans, focusing on ocean pollution, use, and protective measures of the sea and its wildlife. Activities included are "Mythical Monsters"; "Globetrotters"; "Plastic in the Sea"; and "Sea of Many Uses." (RT)

  17. Ocean Disposal Site Monitoring

    EPA Pesticide Factsheets

    EPA is responsible for managing all designated ocean disposal sites. Surveys are conducted to identify appropriate locations for ocean disposal sites and to monitor the impacts of regulated dumping at the disposal sites.

  18. Immunohistochemical localization of gonadotropin releasing hormones in the brain and pituitary gland of the Nile perch, Lates niloticus (Teleostei, Centropomidae).

    PubMed

    Mousa, Mostafa A; Mousa, Shaaban A

    2003-02-15

    In the present study we investigated the distribution of gonadotropin-releasing hormones (GnRH) in the brain of Lates niloticus and their association with different pituitary cell types using immunohistochemical techniques. We found immunoreactive (ir) chicken GnRH-II (cGnRH-II) and mammalian GnRH (mGnRH) as the main components of the GnRH-ir system within the brain of the Nile perch. The results indicate that mGnRH and cGnRH are localized in different neurons: mGnRH-ir perikaria were observed in the preoptic region particularly in the organum vasculosum laminae terminalis (OV