Science.gov

Sample records for ocean perch sebastes

  1. 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.

  2. 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...: NMFS is prohibiting directed fishing for Pacific ocean perch for vessels participating in the rockfish... to prevent exceeding the 2010 total allowable catch (TAC) of Pacific ocean perch allocated to...

  3. Chemical and nutritional properties of Pacific Ocean Perch (Sebastes alutus) whole fish and by-products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to chemically characterize POP and its by-products. Triplicate samples of fresh POP whole fish, heads, frames and viscera were obtained from a commercial processor in Alaska and analyzed. The lipid and protein contents of the POP samples were 7.8% and 17.9% for whole ...

  4. 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...

  5. 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

    ... 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 2010 total allowable catch (TAC) of Pacific ocean perch in the West Yakutat District of the...

  6. 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...

  7. 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...

  8. 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

    ... 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...

  9. 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

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea Subarea of the Bering Sea and Aleutian... 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...

  10. 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

    ... Economic 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...

  11. 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

    ... ocean perch (POP) in the Bering Sea subarea of the BSAI under Sec. 679.20(d)(1)(iii) (78 FR 13813, March... 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...

  12. 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

    ... Economic 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...

  13. 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

    ... 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...

  14. 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...

  15. 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...; modification of a closure. SUMMARY: NMFS is opening directed fishing for Pacific ocean perch by trawl catcher... Pacific ocean perch for trawl catcher vessels participating in the rockfish entry level fishery in...

  16. 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

    ... 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 2010 allocation of Pacific ocean perch in this...

  17. 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...

  18. 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...

  19. 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

    ... 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 2010 allocation of Pacific ocean perch in this...

  20. 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

    ... Economic Zone Off Alaska; Pacific Ocean Perch, Northern Rockfish, and Pelagic Shelf Rockfish in the Western...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch, northern rockfish, and... exceeding the ] 2011 sideboard limits of Pacific ocean perch, northern rockfish, and pelagic shelf...

  1. 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

    ... Economic Zone off Alaska; Northern Rockfish, Pacific Ocean Perch, and Pelagic Shelf Rockfish for Vessels... prohibiting directed fishing for northern rockfish, Pacific ocean perch, and pelagic shelf rockfish for... northern rockfish, Pacific ocean perch, and pelagic shelf rockfish allocated to vessels participating...

  2. 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

    ... 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 2010 allocation of Pacific ocean perch in this...

  3. 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...

  4. 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...

  5. 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

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the Western Yakutat District of the Gulf of Alaska AGENCY.... ACTION: Temporary rule; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch by... appear at subpart H of 50 CFR part 600 and 50 CFR part 679. The 2010 Pacific ocean perch sideboard...

  6. 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...

  7. 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...

  8. 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

    ... 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 2012 total allowable catch (TAC) of Pacific ocean perch in the Western Regulatory Area of the...

  9. 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

    ... 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 2013 total allowable catch of Pacific ocean perch in the Western Regulatory Area of the GOA....

  10. 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...

  11. 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

    ...NMFS is opening directed fishing for Pacific ocean perch by trawl catcher vessels participating in the rockfish entry level fishery in the Central Regulatory Area of the Gulf of Alaska (GOA) for 48 hours. This action is necessary to fully use the 2011 directed fishing allowance of Pacific ocean perch for trawl catcher vessels participating in the rockfish entry level fishery in the Central......

  12. 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...

  13. 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...; modification of closure. SUMMARY: NMFS is reopening directed fishing for Pacific ocean perch by trawl catcher... Alaska (GOA). This action is necessary to fully use the 2010 directed fishing allowance of Pacific...

  14. 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

    ... Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels Participating in the Rockfish Entry Level...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch by trawl catcher vessels...). This action is necessary ] to prevent exceeding the 2011 directed fishing allowance of Pacific...

  15. 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...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific ocean perch by trawl catcher vessels...). This action is necessary to prevent exceeding the 2010 directed fishing allowance of Pacific...

  16. 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

    ...NMFS is opening 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 perch specified for the Bering Sea subarea of the Bering Sea and Aleutian Islands management...

  17. 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...

  18. 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

    ...NMFS is prohibiting directed fishing for Pacific ocean perch in the West Yakutat District of the Gulf of Alaska (GOA). This action is necessary to prevent exceeding the 2012 total allowable catch (TAC) of Pacific ocean perch in the West Yakutat District of the...

  19. 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

    ... Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea Subarea of the Bering Sea and Aleutian...) of Pacific ocean perch in the Bering Sea subarea was established as 4,854 metric tons (mt) by the final 2011 and 2012 harvest specifications for groundfish of the BSAI (76 FR 11139, March 1, 2011)....

  20. 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...

  1. 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...

  2. 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

    ... groundfish in the BSAI (75 FR 11778, March 12, 2010). The harvest specification for the 2010 Pacific ocean... Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea Subarea of the Bering Sea and Aleutian... 2011 harvest specifications for groundfish of the BSAI (75 FR 11778, March 12, 2010). In...

  3. 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

    ... the final 2010 and 2011 harvest specifications for groundfish in the BSAI (75 FR 11778, March 12, 2010... Economic Zone Off Alaska; Pacific Ocean Perch by Vessels in the Amendment 80 Limited Access Fishery in the... participating in the Amendment 80 limited access fishery in the Western Aleutian District of the Bering Sea...

  4. 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.

  5. 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. PMID:26923740

  6. Sea Perch Project

    NASA Technical Reports Server (NTRS)

    2010-01-01

    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.

  7. 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.

  8. 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.

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

    PubMed

    Jang, Yo-Soon; Kim, Sung; Kim, Ki-Yong; Park, Jeong-Ho

    2016-09-01

    Sebastes taczanowskii is a subarctic species in the north-western Pacific Ocean. To obtain mitochondrial DNA sequences for phylogeny, the complete mitogenome (16 452 bp in length) of S. taczanowskii was constructed using next-generation sequencing. The circular mitogenome contains 13 protein-coding genes (PCGs), 2 rRNAs, 22 tRNAs and the control region, for which gene structure and positions were similar to those of other Scorpaenidae. The complete mitogenome composed of 27.8% A, 26.5% T, 17.3% G and 28.5% C, with a slight AT bias (54.3%). All PCGs use a typical start codon, ATG, except COX1 (GTG). The terminal codon of PCGs was mainly TAR, with the exceptions of ND4 (AGA) and Cytb (incomplete codon, T). Sebastes taczanowskii was clearly divided from other Scorpaenidae in the phylogenetic tree using 2 rRNA and 13 PCGs. The mitogenome of S. taczanowskii can be useful for constructing the molecular phylogenetic tree within Scorpaenidae. PMID:26273922

  10. 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'.

  11. Food of white perch, rock bass and yellow perch in eastern Lake Ontario

    USGS Publications Warehouse

    Elrod, Joseph H.; Busch, Wolf-Dieter N.; Griswold, Bernard L.; Schneider, Clifford P.; Wolfert, David R.

    1981-01-01

    The contents of stomachs from 1,485 white perch, 218 rock bass and 1,399 yellow perch collected in eastern Lake Ontario from May to October in 1972 and in May 1973 were examined. All three species fed primarily on amphipods, but they also ate chironomids and trichopterans regularly. Rock bass ate more trichopterans than chironomids, whereas white perch and yellow perch ate more chironomids. Snails and crayfish were significant items in the diet of rock bass, but occurred infrequently in stomachs of white perch and yellow perch. White perch and yellow perch frequently ate fish eggs during early summer, but rock bass seldom ate fish eggs. Fish were important in the diets of white perch longer than 300 millimeters and rock bass and yellow perch longer than 200 millimeters. Similarities in the diets of fish 1 year old or older suggest that the potential for competition between white perch and yellow perch is greater than that between rock bass and either white perch or yellow perch.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Improving Growth in Yellow Perch (Perca flavescens)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Given that the role of the somatotropic axis (e.g. growth hormone and insulin-like growth factor I) in yellow perch growth is uniquely unresolved, and the interplay of sex steroids with the somatotropic axis unknown, research efforts are focused in this area. To accomplish this, we will isolate and...

  17. 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.

  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. 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

  20. Perch use by laying hens in a commercial aviary.

    PubMed

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

    2016-08-01

    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

  1. 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.

  2. 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. PMID:21671502

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  4. 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. PMID:24438257

  5. 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. PMID:24438255

  6. Lack of population genetic differentiation of a marine ovoviviparous fish Sebastes schlegelii in Northwestern Pacific.

    PubMed

    Zhang, Hui; Yanagimoto, Takashi; Zhang, Xiumei; Song, Na; Gao, Tianxiang

    2016-05-01

    Sebastes schlegelii is one of the fishes that aggregate around drifting seaweed during early development. To examine the population genetic structure of S. schlegelii, a 452-bp fragment of the mtDNA control region was sequenced and used to interpret life history characteristics and larval dispersal strategy. Two-hundred and twenty-one individuals from 13 sites across the entire range of S. schlegelii in China, Japan and Korea were analyzed. A neighbor-joining tree and network showed that there were no significant genealogical structures corresponding to sampling locations. AMOVA, pair-wise FST and exact test revealed no significant genetic differentiation among locations. The migration rate among locations was high based on the result of LAMARC. We conclude that larval dispersal with drifting seaweed and the current environmental factors may play an important role in shaping the contemporary phylogeographic pattern and genetic homogeneity of S. schlegelii. PMID:25269000

  7. Bathymetric-based habitat model for yelloweye rockfish (Sebastes ruberrimus) on Alaska's outer Kenai Peninsula

    NASA Astrophysics Data System (ADS)

    Mumm, Joshua D.

    Motivated primarily as part of a habitat-based stock assessment, we explored the feasibility of modeling yelloweye rockfish (Sebastes ruberrimus) habitat in Southcentral Alaska using high-resolution multibeam bathymetry. A generalized linear model was developed with bathymetrically derived terrain metrics (rugosity, slope, bathymetric position index, and distance-to-rock) as predictor variables. The model was parameterized and validated using remotely operated vehicle observations. When evaluated for the Chiswell Island training area, the model correctly classified 96.0% (n = 100) of a reserved set of presence/absence validation points (Cohen's Kappa = 0.92; AUC = 0.98). When evaluated for the independent Nuka Island testing area, the overall accuracy was 82.5% (n=332; Kappa = 0.65; AUC = 0.95). This study demonstrates that suitable yelloweye habitat can be modeled with reasonable accuracy using high-resolution multibeam bathymetry, and such a model is fairly portable among sites along the Kenai Peninsula's outer coast.

  8. 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.

  9. 76 FR 70420 - Fisheries of the Pacific Region

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-14

    ... National Oceanic and Atmospheric Administration RIN 0648-XA801 Fisheries of the Pacific Region AGENCY... that NMFS, on behalf of the Secretary of Commerce (Secretary), has determined that Pacific ocean perch, (Sebastes alutus), which is managed by the Pacific Fishery Management Council, is in an overfished...

  10. A health assessment of high status Christian burials recovered from the Roman-Byzantine archeological site of Elaiussa Sebaste, Turkey.

    PubMed

    Paine, R R; Vargiu, R; Coppa, A; Morselli, C; Schneider, E E

    2007-01-01

    The purpose of this study is to assess the state of health of 116 individuals whose remains were excavated from Byzantine period burials underneath the floor of an important Christian basilica from the site of Elaiussa Sebaste, Turkey. Elaiussa Sebaste was a Mediterranean coastal community, which began as a Roman town and continued as an early Christian Byzantine community until the end of the 7th century AD. The burials date from the middle of the 6th through the middle of the 7th centuries AD. We attempt to determine how high social status has influenced the type and frequency of skeletal lesions exhibited in this sample. All strata of this population show a number of chronic and acute health problems as indicated by skeletal lesions. Yet, only the frequency of degenerative joint disease (DJD) differs by sex, with males exhibiting a higher rate of DJD than females, p=0.09. There is no difference in the frequency of trauma among adult males and females. Non-specific skeletal lesions (cribra orbitalia, porotic hyperostosis, and periostitis) often associated with dietary and general stressors, but also with specific systemic diseases, are common in both sexes. The sub-adults primarily exhibit periostitis of the long bones and do not show skeletal lesions specific to malaria. It seems that high social ranking did not prevent serious ailments from affecting the health of individuals living in the Elaiussa Sebaste community. PMID:17433326

  11. Reappraising factors affecting mourning dove perch coos

    USGS Publications Warehouse

    Sayre, M.W.; Atkinson, R.D.; Baskett, T.S.; Haas, G.H.

    1978-01-01

    Results confirmed pairing as the primary factor influencing perch-cooing rates of wild mourning doves (Zenaida macroura). Marked unmated males cooed at substantially higher rates (6.2x) than mated males, had greater probability of cooing (2.3x) during 3-minute periods, and continued cooing longer each morning than mated males. Population density was not a major factor affecting cooing. Unmated males cooed more frequently in the presence of other cooing doves (P < 0.05) than when alone, but the number of additional doves above 1 was unimportant. Cooing rates of both mated and unmated males on areas with dissimilar dove densities were not significantly different. Within limits of standard call-count procedure, weather exerted no detectable influence on cooing.

  12. 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.

  13. 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. PMID:22539208

  14. 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.

  15. 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. PMID:25101853

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. Daily growth increments in otoliths of juvenile black rockfish, Sebastes melanops: an evaluation of autoradiography as a new method of validation

    SciTech Connect

    Not Available

    1988-10-01

    This study evaluates the commonly used oxytetracycline hydrochloride (OTC) and an alternate chemical, the radioisotope calcium-45, in terms of their success as time-markers to validate daily growth increment formation in the otoliths of juvenile black rockfish, Sebastes melanops.

  2. Use of tetracycline hydrochloride and alizarin complexone for immersion marking black rockfish Sebastes schlegelii

    NASA Astrophysics Data System (ADS)

    Lü, Hongjian; Zhang, Xiumei; Fu, Mei; Xi, Dan; Gao, Tianxiang

    2014-07-01

    We tested the utility of chemical marking techniques in the juvenile black rockfish Sebastes schlegelii. Juveniles (30-40 mm total length) were immersed in a range of tetracycline hydrochloride (TC) solutions at concentrations ranging from 300 to 500 mg/L, and alizarin complexone (ALC) solutions at concentrations ranging from 200 to 400 mg/L in filtered sea water (salinity of 30) for 24 h, respectively. Otoliths (sagittae, asteriscus), scales, fin rays (dorsal, pectoral, ventral, anal, and caudal fin rays), and fin spines (dorsal, ventral, and anal fin spines) were sampled and used to detect fluorescent marks after a 60-day growth experiment. With the exception of 300 mg/L TC, acceptable marks were produced in the otoliths and fin spines by all concentrations of TC and ALC. In particular, we observed clearly visible marks in the sagittae, asteriscus, and fin spines under normal light at concentrations of 200-400 mg/L, 250-400 mg/L, and 250-400 mg/L ALC, respectively. Scales and fin rays had acceptable marks at much higher concentrations (≥350 mg/L TC, ≥250 mg/L ALC for scales and ≥350 mg/L TC, ≥300 mg/L ALC for fin rays). The best mark quality (i.e., acceptable marks were observed in all sampled structures after immersion marking) were obtained following immersion in TC at between 350-500 mg/L, and ALC between 300-400 mg/L. In addition, there was no significant difference in survival and growth of TC and ALC marked fish compared to their controls up to 60 days post-marking ( P > 0.05).

  3. 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. PMID:27070008

  4. Cloning and expression analysis of a HSP70 gene from Korean rockfish (Sebastes schlegeli).

    PubMed

    Mu, Weijie; Wen, Haishen; Li, Jifang; He, Feng

    2013-10-01

    The gene encoding HSP70 was isolated from Korean rockfish Sebastes schlegeli by homologous cloning and rapid amplification of cDNA ends (RACE). The full-length of HSP70 cDNA was composed of 2259 bp and encoded a polypeptide of 639 amino acids. BLAST analysis showed that HSP70 of S. schlegeli shared high identities with those of the Lates calcarifer, Oreochromis niloticus, Seriola quinqueradiata HSP70s (88-89%). Our current study also revealed that HSP70 of Korean rockfish was expressed in many tissues by RT-PCR under unstressed condition. Quantitative real-time PCR showed that the expression patterns of Korean rockfish HSP70 were developmental stage-dependency. The expression of HSP70 was measured by quantitative real-time PCR after different oxygen treatments. The results showed that expression of HSP70 increased significantly after exposure to hypoxia for 30 min in gill and ovary, and then decreased for 60 min, and the level in spleen and liver gradually increased and reached the highest at 60 min. In addition, in gill, spleen and liver, the HSP70 mRNA level reached the maximum in hypoxia group after one hour different oxygen concentration stress. Increased amounts of serum thyroxine (T4), and triiodothyronine (T3) were also found during 30 min hypoxia treatment and 60 min normoxia group in our study. All of the results provide information to further study the mechanism of physiology and immune function under stress conditions of ovoviviparous teleosts. PMID:23877000

  5. Antihelminthic potential of quinacrine and oxyclozanide against gill parasite Microcotyle sebastis in black rockfish Sebastes schlegeli.

    PubMed

    Kang, Yue Jai; Wakabayashi, Chizuha; Kim, Ki Hong

    2016-05-26

    The aim of this study was to assess the treatment potential of quinacrine and oxyclozanide against Microcotyle sebastis (Monogenea: Polyopisthocotylea) infection in cultured black rockfish Sebastes schlegeli. The oral administration of quinacrine led to a reduction in the mean abundance of M. sebastis infection in all quinacrine-treated groups, and the groups of fish administered quinacrine at 50, 100, and 200 mg kg(-1) for 3 consecutive days showed a parasite mean abundance that was 50 to 30% lower compared to that of the control group, suggesting that quinacrine has a therapeutic potential against M. sebastis. Although oxyclozanide showed a very high in vitro killing activity, in oral administration experiments, only the groups of fish administered 200 mg kg(-1) showed less than 50% mean abundance of M. sebastis compared to the control groups, suggesting that the absorption efficiency of orally administered oxyclozanide might be low in black rockfish and/or that M. sebastis might be less sensitive to orally ingested oxyclozanide. As praziquantel has been the sole therapeutic against M. sebastis infection in Korea for a long time, a broadening of available control measures is advisable in order to reduce the possible emergence of praziquantel-resistant M. sebastis. In our study, although quinacrine and oxyclozanide showed a therapeutic potential against M. sebastis, the treatment efficacy was not high enough to replace praziquantel. Thus, after investigations on the pathological effects and pharmacodynamics, use of quinacrine or oxyclozanide in combination with praziquantel may be considered as a way to prevent praziquantel resistance in M. sebastis. PMID:27225210

  6. 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.

  7. A transcriptomic scan for positively selected genes in two closely related marine fishes: Sebastes caurinus and S. rastrelliger.

    PubMed

    Heras, Joseph; Koop, Ben F; Aguilar, Andres

    2011-06-01

    Comparative genomic analyses can provide valuable insight into functional evolutionary divergence among closely related species. Here we employ a comparative evolutionary analysis of expressed sequence tags (ESTs) from two closely related species of marine fishes (genus Sebastes--rockfish). Sebastes is a highly diverse group of marine fishes that inhabit a wide array of marine habitats and the study of this group can provide insights into speciation in the marine environment. ESTs were developed for S. caurinus (23,668 from brain, kidney, and spleen tissues) and S. rastrelliger (11,207 from brain and pituitary tissues). Following assembly we were able to identify, with high confidence, 257 orthologous sequence pairs between the two species through a reciprocal best hit blast search. An analysis of functional divergence between orthologs revealed that 19.46% had Ka/Ks values greater than 0.5 and 8.17% had Ka/Ks values greater than one, identifying a large pool of candidate genes to further study adaptive divergence in the group. Genes with elevated Ka/Ks values belonged to the following functional categories: immune function, metabolism, longevity, and reproductive behavior, indicating that adaptive divergence in these functional groups may be important in the diversification of this group of fishes. This study provides the ground work to better understand the molecular evolution of genes involved in a radiation of marine fishes. PMID:21620330

  8. 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

  9. Developing Genetically Defined Yellow Perch (Perca flavescens) Broodstocks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yellow Perch are an ecologically and economically important species common in Midwest commercial aquaculture. Broodstocks are traditionally derived from wild populations locally accessible to the producer. This can lead to inconsistencies in the success of producers within and between regions. Su...

  10. 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.

  11. WATER DISPLACEMENT DURING SPARGING UNDER PERCHED WATER-TABLE CONDITIONS

    EPA Science Inventory

    The feasibility of using sparging to purposefully displace perched water in silt loam soils was evaluated at a field site in Northwestern Oklahoma. uring sparging, a transient response in water level measurements was observed in observation wells which is attributed to water disp...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  13. 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

  14. 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. PMID:23251505

  15. 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

  16. Impact of impingement on the Hudson River white perch population

    SciTech Connect

    Barnthouse, L W; Van Winkle, W

    1980-01-01

    The impact of power plant impingement on the 1974 and 1975 year classes of the Hudson River white perch population is assessed using a simple model derived from Ricker's theory of fisheries dynamics. The impact of impingement is expressed in the model as the conditional mortality rate, rather than as the more commonly used exploitation rate. Since the calculated impact is sensitive to errors in the estimation of population size and total mortality, ranges of probable values of these quantities are used to compute upper and lower bounds on the fractional reduction in abundance of each year class. Best estimates of abundance and mortality are used to compute the conditional impingement mortality rate separately for each plant and month. The results are used to assess the relative impacts of white perch impingement at six Hudson River power plants and to identify the seasons during which the impact is highest.

  17. Splenic lipidosis in intensively cultured perch, Perca fluviatilis L.

    PubMed

    Stejskal, V; Kouřil, J; Policar, T; Svobodová, Z

    2016-01-01

    Macroscopically visible lipid deposition varying in size from pinpoint to 8-mm diameter was found in spleens of a population of intensively farmed perch, Perca fluviatilis L. over a 24-month rearing period. Large agglomerates of adipocytes distinguishable from surrounding normal tissue occurred in all individuals with spleen lipidosis. Several affected fish presented total dystrophy of large clusters of hepatocytes. Prevalence of lipidosis was 5.0% at 12 months and 16.6% at 24 months. There was no significant difference between fatty acid profiles of liver or perivisceral fat of perch with and without lipidosis except for linoleic, myristic, γ-linoleic, cis-eicosatrienic, palmitooleic acid. Body weight and hepatosomatic, perivisceral fat and splenosomatic indices were not associated with lipidosis. There was no significant effect of lipidosis on mortality or growth. PMID:25589287

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

    USGS Publications Warehouse

    Loope, Walter L.; McEachern, A. Kathryn

    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.

  19. 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.

  20. 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.

  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. PMID:26723759

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  4. 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

  5. Development of Genetically-defined Yellow Perch (Perca flavescens) Broodstocks for Selective Breeding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have initiated development of genetically defined yellow perch (Perca flavescens) broodstocks. For this, sixteen wild perch populations throughout the U.S. were sampled and analyzed using published (Leclerc et al. Molecular Ecology 2000, 9: 993-1011) and newly developed microsatellite loci. Gen...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  7. 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

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

    PubMed

    Wen, Chiu-Ming; 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

  9. 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

  10. Depletion of praziquantel in plasma and muscle tissue of cultured rockfish Sebastes schlegeli after oral and bath treatment.

    PubMed

    Kim, K H; Kim, C S; Kim, J W

    2001-08-01

    Depletion of praziquantel in plasma and muscle tissue after oral and bath treatments was studied in cultured rockfish Sebastes schlegeli. In the oral treatment, a single dose of 400 mg praziquantel kg(-1) body weight was administered by intubation of the stomach. A bath treatment at 100 ppm of praziquantel for 4 min was also carried out. Plasma and muscle tissue samples were collected at 3, 6, 12, 24, 48, 72, 96, 120, 144 and 168 h post-treatment, and analyzed for praziquantel by reversed-phase HPLC using diazepam as the internal standard. Following oral treatment, praziquantel was detected in plasma and muscle tissue until 96 h after treatment. In plasma the praziquantel concentration was highest at the 9 h sampling time and declined sharply at the 48 h sampling point. The concentrations of praziquantel in the muscle tissue were lower than those in the plasma, and the highest value was found at the 9 h sampling time. Following bath treatment, praziquantel was found in plasma and muscle tissue until 72 and 24 h after treatment, respectively. In plasma the praziquantel concentration was highest at the 12 h sampling time and declined sharply thereafter. The concentrations of praziquantel in the muscle tissue were significantly lower than those in the plasma, and the concentrations declined consistently with time. PMID:11558729

  11. 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.

  12. Immunological and health-state parameters in the Patagonian rockfish Sebastes oculatus. Their relation to chemical stressors and seasonal changes.

    PubMed

    Sueiro, Maria Cruz; Palacios, María Gabriela

    2016-01-01

    We present the results of a field study that evaluates whether exposure to anthropogenic pollution impacts immunological and health-state parameters of wild marine fish during the breeding and non-breeding periods. We assessed aspects of innate immunity (bactericidal capacity, bacterial agglutination, and leukocyte profile) and general health-related parameters (neutrophil to lymphocyte ratio, hematocrit, and condition factor) in the Patagonian rockfish (Sebastes oculatus) sampled from polluted (exposed) and reference (control) sites during winter (i.e., coolest temperatures and active reproductive period) and in summer (i.e., warmest temperatures and non-reproductive period). Results showed lower bactericidal competence, hematocrit, and condition factor in fish from exposed sites independently of season, whereas lymphocytes were higher and monocytes lower at the exposed site only during summer. Moreover, fish sampled during winter displayed lower bactericidal competence, hematocrit, and condition factor than those sampled in summer independently of site, whereas the opposite pattern was found for bacterial agglutination. These results could be explained by life-history theory, which predicts a re-allocation of resources between reproduction and other physiological functions (including immunity) during the most energetically demanding season. The present results show an alteration in immunological and health-state parameters of wild marine fish exposed to anthropogenic pollution independently of season, which could potentially result in higher susceptibility to disease and in turn population decline. PMID:26584758

  13. 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. PMID:26991846

  14. Special structure of mitochondrial DNA control region and phylogenetic relationship among individuals of the black rockfish, Sebastes schlegelii.

    PubMed

    Zhang, Hui; Zhang, Yan; Zhang, Xiumei; Song, Na; Gao, Tianxiang

    2013-04-01

    This study deals with the structure of mitochondrial DNA (mtDNA) control region (CR) of the black rockfish, Sebastes schlegelii. Two termination-associated sequences (TASs), two complementary termination-associated sequences (cTASs), and conserved sequence block (CSB), such as CSB-F, CSB-E, CSB-D, CSB1, CSB2, and CSB3, were detected in S. schlegelii. The results indicated that the structures of these blocks are similar to most marine fishes, but it is special that there are two TASs and two cTASs in the CR of S. schlegelii. One conserved region was found from 450 bp to the end of the CR, which is also a special feature of S. schlegelii. All sequences of CSB1, CSB2, and CSB3 blocks are the consensus among different individuals, which is quite different from most vertebrates. In addition, the complete mtDNA CR sequences and the first 449 bp of the CR are used to analyze the phylogenetic relationships of S. schlegelii. The phylogenetic trees show a lack of genetic structure among individuals. This study also indicated a signal that the genetic diversity might be similar between the wild and cultured individuals, which may be helpful to the fisheries management. PMID:23072475

  15. Effects of perch access and age on physiological measures of stress in caged White Leghorn pullets.

    PubMed

    Yan, F F; Hester, P Y; Enneking, S A; Cheng, H W

    2013-11-01

    The neuroendocrine system controls animals' adaptability to their environments by releasing psychotropic compounds such as catecholamines [epinephrine (EP), norepinephrine (NE), and dopamine (DA)], corticosterone (CORT), and serotonin (5-hydroxytryptamine or 5-HT). Changes of these neuroendocrine compounds have been used as biomarkers of animals' stress responses associated with their well-being. Assuming that pullets, like laying hens, are highly motivated to perch, we hypothesize that pullets with access to perches will experience less stress than pullets that never have access to perches. The objective of this study was to examine the effects of perch access and age on physiological measurements of stress in White Leghorn pullets housed in conventional cages. Hatchlings (n = 1,064) were randomly assigned to 28 cages. Two parallel metal round perches were installed in each of 14 cages assigned the perch treatment, whereas control cages were without perches. Two birds per cage were bled at wk 4, 6, and 12 wk of age. Plasma levels of CORT, DA, EP, and NE, blood concentrations of 5-HT and Trp, and heterophil to lymphocyte ratios were measured. Data were analyzed using a 2-way ANOVA. The perch treatment or its interaction with age did not affect any parameter measured in the study. The increase in the concentrations of circulating EP, NE, 5-HT (numerical increase at 4 wk), and Trp in 4- and 6-wk-old pullets compared with 12-wk-old pullets is unclear, but may have been due to acute handling stress at younger ages. In contrast, concentrations of DA were less at 4 wk compared with levels at 6 and 12 wk of age. Plasma CORT levels and the heterophil to lymphocyte ratio, indicators of long-term stress, were unaffected by age (P = 0.07 and 0.49, respectively). These results indicated that age, but not perch access, affects neuroendocrine homeostasis in White Leghorn pullets. Pullets that were never exposed to perches showed no evidence of eliciting a stress response. PMID

  16. 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.

  17. Changes in yellow perch (Perca flavescens) populations of Lake Michigan, 1954-75

    USGS Publications Warehouse

    Wells, LaRue

    1977-01-01

    In the early and mid-1960s the abundance of yellow perch (Perca flavescens) in Lake Michigan declined abruptly. The decline began in the northern part of the lake and spread progressively southward. Circumstantial evidence suggests that the nonnative alewife (Alosa pseudoharengus), by interfering with perch reproduction, was the primary cause of the decline. The alewife was first reported in northeastern Lake Michigan in 1949, and had become extremely abundant throughout the lake before an enormous die-off in 1967 reduced its numbers by an estimated 70%. An intensive fishery hastened the decline of perch. In most areas the decline was immediately preceded by a period of conspicuously high commercial production. This high production appears to have been related in part to increased growth rates of perch resulting from much lower density of younger fish. A sport fishery for perch in shallow water collapsed a few years before the species declined in abundance. The most logical explanation is that heavy concentrations of alewives physically displaced the perch from nearshore areas. Although perch populations increased in some areas in the 1970s, a full recovery is unlikely unless alewife numbers are further reduced.

  18. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  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. 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).

  6. Perched water tables on hillsides in western Oregon: II. Preferential downslope movement of water and anions.

    USGS Publications Warehouse

    Hammermeister, D.P.; Kling, G.F.; Vomocil, J.A.

    1982-01-01

    Reports the results of experiments which were carried out to investigate the flow of solutes and water from buried line sources in and above perched water tables on three different hillsides in W Oregon. -from Authors

  7. Methods to assess impacts on Hudson River white perch, October 1, 1978-September 30, 1979

    SciTech Connect

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

    1980-05-01

    This report is a brief description of the work done during the period October 1, 1978 to September 30, 1979. During this period, a final draft topical report entitled ''Evaluation of Impingement Losses of White Perch at the Indian Point Nuclear Station and Other Hudson River Power Plants'' (NUREG/CR-1100) was completed. In addition, special studies of white perch entrainment at Hudson River powder plants, of density-dependent growth in the Hudson River white perch population, and of data on the white perch populations of the Delaware and Chesapeake systems were performed. Most of the results obtained during FY 79 were incorporated in testimony written for the ongoing adjudicatory hearing on the Hudson River Power Case (Region II). 13 tabs.

  8. Perching and takeoff of a robotic insect on overhangs using switchable electrostatic adhesion.

    PubMed

    Graule, M A; Chirarattananon, P; Fuller, S B; Jafferis, N T; Ma, K Y; Spenko, M; Kornbluh, R; Wood, R J

    2016-05-20

    For aerial robots, maintaining a high vantage point for an extended time is crucial in many applications. However, available on-board power and mechanical fatigue constrain their flight time, especially for smaller, battery-powered aircraft. Perching on elevated structures is a biologically inspired approach to overcome these limitations. Previous perching robots have required specific material properties for the landing sites, such as surface asperities for spines, or ferromagnetism. We describe a switchable electroadhesive that enables controlled perching and detachment on nearly any material while requiring approximately three orders of magnitude less power than required to sustain flight. These electroadhesives are designed, characterized, and used to demonstrate a flying robotic insect able to robustly perch on a wide range of materials, including glass, wood, and a natural leaf. PMID:27199427

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. Perched water tables on hillsides in western Oregon: I. Some factors affecting their development and longevity.

    USGS Publications Warehouse

    Hammermeister, D.P.; Kling, G.F.; Vomocil, J.A.

    1982-01-01

    Perched water tables on hillsides located on the western border of the Willamette Valley in Oregon in some cases have the potential to transport pollutants from either domestic or agricultural sources downslope to streams, ponds, or reservoirs, resulting in the deterioration of the quality of these waters. Some factors responsible for the development and longevity of these potentially problem-causing perched water tables on three hillsides were examined. -from Authors

  14. 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. PMID:18268301

  15. Susceptibility of Australian Redfin Perch Perca fluviatilis Experimentally Challenged with Epizootic Hematopoietic Necrosis Virus (EHNV).

    PubMed

    Becker, Joy A; Tweedie, Alison; Gilligan, Dean; Asmus, Martin; Whittington, Richard J

    2016-06-01

    The ranavirus epizootic hematopoietic necrosis virus (EHNV) is endemic to Australia and is listed by the Office International des Epizooties. Clinical outbreaks have only been observed in wild populations of Redfin Perch Perca fluviatilis (also known as Eurasian Perch) and farmed populations of Rainbow Trout Oncorhynchus mykiss. The initial outbreaks of EHNV describe all age-classes of Redfin Perch as being susceptible and can lead to epidemic fish kills. Subsequently, experimental challenge studies using either cohabitation with the virus or injection exposures resulted in mixed susceptibilities across various age-groupings of Redfin Perch. We used an experimental bath challenge model to investigate the susceptibility of Redfin Perch collected from areas with and without a history of EHNV outbreaks. The median survival time for fish from Blowering Dam in New South Wales, a zone with a history of EHNV outbreaks, was 35 d, compared with fish from other areas, which had a median survival between 12 and 28 d postexposure. Redfin Perch from Blowering Dam demonstrated an increased mortality associated with epizootic hematopoietic necrosis up to approximately day 14 after exposure, and then there was a significantly reduced risk of mortality until the end of the trial compared with all other fish. Redfin Perch from Blowering Dam had markedly decreased susceptibility to EHNV, and less than 40% became infected following a bath challenge. In contrast, Redfin Perch from neighboring (e.g., Bethungra Dam and Tarcutta Creek) and distant water bodies (e.g., in Western Australia) with no previous history of EHNVdisplayed moderate to high susceptibility when given a bath challenge. Potential factors for the observed changes in the host-pathogen relationship include intense positive selection pressure for resistant fish following epizootic hematopoietic necrosis outbreaks and subsequent attenuation of the virulence of the virus in resistant fish. Received August 22, 2015; accepted

  16. 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.

  17. 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).

  18. 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.

  19. Modelling perched river recharge to the Wairau aquifer, New Zealand

    NASA Astrophysics Data System (ADS)

    Wöhling, Thomas; Gosses, Moritz; Wilson, Scott; Davidson, Peter

    2015-04-01

    The Wairau Aquifer in Marlborough, New Zealand, consists of coarse, high-conductive alluvial gravels and is almost exclusively recharged by surface water from the braided Wairau River. Recent experimental evidence suggests that the river is perched in the upstream recharge region of the aquifer. The aquifer serves as the major drinking water resource for the city of Blenheim and the surrounding settlements on the Wairau Plain and thus is a key natural resource for the region. To ensure the sustainable management of the resource, it is essential to better understand the limits and the mechanics of the recharge mechanism. One efficient way to test hypotheses of the mechanisms for river-groundwater exchange fluxes between the Wairau river and aquifer is by data integration into numerical models that mimic the flow regime of the coupled hydrological system. For that purpose, a Modflow model for the Wairau Aquifer was to set up and calibrated under summer conditions when the flow in the river is low and the aquifer is most vulnerable to over-allocation. The model is constrained by knowledge about the hydrogeological settings as well as observations of groundwater levels, river and spring flow gaugings, and analysis of aquifer pumping tests. Both historic and more recent concurrent river flow measurements under low flow conditions suggest that approximately 7-8 m³/s is recharged into the aquifer along the upper and middle reaches, at least partly under perched conditions. At the eastern side of the aquifer, a small proportion of that water flows back into the river, whereas a greater proportion emerges in springs. Spring creek is the largest spring with an estimated mean flow of 4.0 m³/s. This flow rate is vulnerable to an excessive decline in groundwater levels. The simulations with the calibrated flow model fit well to the observations of current mean groundwater heads as well as to mean Wairau river and Spring creek flows. Modeling results suggest a large spatial

  20. 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

  1. 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. PMID:26440307

  2. 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.

  3. 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.

  4. Steady State Perched Groundwater Mounds on Thick Sublayers

    NASA Astrophysics Data System (ADS)

    Brock, Richard R.

    1982-04-01

    Perched mounds that develop beneath a strip recharge basin are considered using the potential theory for a saturated flow. The mounds are assumed to develop upon an aquitard or sublayer whose thickness is large enough so that the vertical velocity at the base of the mound does not vary with distance from the centerline of the basin. A finite difference technique was used to solve the potential theory, and 20 mound profiles were determined for K/KL = 10, 50, 100, 500 and R/K = 0.2, 0.35, 0.50, 0.65, 0.80. K/KL is the ratio of the permeabilities, and R is the recharge rate. These profiles are compared to those based on the approximate Dupuit-Forchheimer (DF) theory, and a criterion for the range of validity of the DF theory for predicting the maximum mount thickness H0 is derived. It is found that for a sufficiently large value of K/KL, which depends on R/K and the desired accuracy, the DF theory is adequate. For smaller values of K/KL the potential theory must be used. Equipotential lines and velocity distributions are presented for a typical case where the potential and DF mound profiles are quite different.

  5. 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.

  6. Communication in the third dimension: song perch height of rivals affects singing response in nightingales.

    PubMed

    Sprau, Philipp; Roth, Tobias; Naguib, Marc; Amrhein, Valentin

    2012-01-01

    Many animals use long-range signals to compete over mates and resources. Optimal transmission can be achieved by choosing efficient signals, or by choosing adequate signalling perches and song posts. High signalling perches benefit sound transmission and reception, but may be more risky due to exposure to airborne predators. Perch height could thus reflect male quality, with individuals signalling at higher perches appearing as more threatening to rivals. Using playbacks on nightingales (Luscinia megarhynchos), we simulated rivals singing at the same height as residents, or singing three metres higher. Surprisingly, residents increased song output stronger, and, varying with future pairing success, overlapped more songs of the playback when rivals were singing at the same height than when they were singing higher. Other than expected, rivals singing at the same height may thus be experienced as more threatening than rivals singing at higher perches. Our study provides new evidence that territorial animals integrate information on signalling height and thus on vertical cues in their assessment of rivals. PMID:22448215

  7. 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

  8. 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. PMID:27184325

  9. 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.

  10. 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

  11. 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

  12. 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. PMID:27276078

  13. Stimulation of Growth and Changes in the Hepatic Transcriptome by Estradiol-17-Beta in the Yellow Perch (Perca flavescens)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of dietary estradiol-17-beta (E2) on growth and liver transcriptomics were investigated in the yellow perch (Perca flavescens). Following a 3-month treatment, E2 significantly stimulated an increase in length and weight of juvenile male and female perch relative to controls. The increas...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  16. 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.

  17. 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.

  18. 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.

  19. 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. PMID:26480912

  20. Rearing without early access to perches impairs the spatial skills of laying hens.

    PubMed

    Gunnarsson; Yngvesson; Keeling; Forkman

    2000-04-01

    The effect of rearing with and without perches on the spatial ability of domestic hens (Gallus gallus domesticus) was investigated. No access or late access to perches during rearing has been shown to increase the later prevalence of floor eggs and cloacal cannibalism in loose-housed laying hens. This may be explained by either the birds reared without perches have difficulty using perches due to low muscle strength, lack of motor skills, and inability to keep balance, or they have impaired spatial skills necessary for moving around in three-dimensional space. These alternative explanations are not mutually exclusive.Thirty, day-old chicks were randomly allocated into two equal groups and reared in litter pens, one with access to perches (P+) and one without (P-). At 8 weeks of age, all birds were given access to perches, and by 15 weeks, all birds were using perches for roosting at night. At 16 weeks, 10 birds from each group were tested in pens where food was presented on a wire mesh tier 40 cm above the ground (T40). Three consecutive tests, with increasing difficulty for the bird to reach the food, were then performed. Firstly, the food was presented at 80 cm above the ground but with the tier at 40 cm still present; secondly, food was presented on the tier at 80 cm; and then, finally, with the food on a 160 cm high tier with the tier at 80 cm still present. All birds were food deprived for 15 h before each test and the time from the bird entering the pen until reaching the food was recorded. There was no difference in the time to reach the food between P+ and P- birds in the T40 test. But as the difficulty of the task increased, the difference between the P+ and P- birds became significant, with the P- birds taking a longer time to reach the food or not reaching it at all. Since there was no difference between P+ and P- in the T40 test, it seems reasonable to suppose that the later differences did not depend on differences in physical ability. Therefore, the

  1. Microsatellite Analysis of Perch (Perca fluviatilis) and its Genetic Authentication of Geographical Localization.

    PubMed

    Rolli, Joelle; Girardet, Sylvie; Monachon, Cédric; Richard, Christian

    2014-10-01

    European perch (Perca fluviatilis) is an economically important freshwater species in Europe. In Switzerland, where the demand largely exceeds the production coming from Swiss lakes, nearly 90% of the requirements come from importation with the majority of perch originating from Estonia and Russia. The price of perch fillet varies considerably depending on the origin. Therefore traceability in the fish food sector plays an increasingly important role for consumer protection. Currently the traceability of perch can be assessed through chemical isotopic analysis. The 180/160 isotopic abundance ratio is used as geographical traceability marker, but several aspects affect the accuracy of the method, i.e. the distinct geographical area ratio differs only very slightly with overlapping standard deviation, the need for a large amount of fish material requires the mix of many fillets, the impossibility of analyzing processed matrix, the comparison of the ratio with the ratio of a sample of the presumed originating water makes the analyses more complicated. New application of DNA markers for the traceability of food products plays an increasingly important role for consumer protection. Microsatellites, which are short tandemly repetitive DNA sequences, are genetic markers of choice for traceability because of their abundance and high polymorphism. Moreover, fluorescent labelling and capillary electrophoresis separation increase efficiency and precision of genotyping microsatellites. The method can also be efficiently applied in processed food products where other methods have limited applications. In this study, we tested the efficiency of three polymorphic microsatellites and their combinations for their ability to correctly assign or exclude 195 reference perch to their origin population. Using the maximum likelihood and Bayesian methods computed by the software GeneClass2, the three loci microsatellite were optimized and allowed the correct assignation of all but two

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  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

  5. Identification and virulence of Chryseobacterium indologenes isolated from diseased yellow perch (Perca flavescens)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fifteen Gram-negative bacteria isolates were recovered from the skin lesions of diseased yellow perch (Perca flavescens). Based on API 20NE test results, ten isolates were found to share 67.2% to 99.9% homologies with Chryseobactertium indologenes. Based on results of fatty acid methyl ester analys...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  7. 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.

  8. The effect of perches installed in conventional cages on White Leghorn pullets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enrichments for laying cages are receiving increasing attention by egg producers as a means of meeting the behavioral needs of laying hens. Pullet cage enrichments have received less attention and study. Adapting pullets to perches prior to placement in enriched laying cages may offer health and wel...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  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. PMID:11020069

  11. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  14. 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.

  15. 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.

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

    PubMed

    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

  17. 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

  18. 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. PMID:16134370

  19. 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.

  20. Impingement losses of white perch at Hudson River power plants: magnitude and biological significance

    SciTech Connect

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

    1983-01-01

    A quantitative assessment of the impact of impingement at power plants on the Hudson River white perch population was made. It was estimated that impingement reduces the abundance of each white perch year class by at least 10% and probably by 15-20% or more after 2-3 years of vulnerability to power plants. Effects of impingement on average year-class abundance of white perch could not be detected from a time series of abundance indices derived from impingement data. Even if a reliable index were developed, natural fluctuations in year-class strength are great enough that a short-term monitoring program would be inadequate for detecting even a large reduction in average year-class strength. A multipopulation analysis was performed using simple food chain and food web models. The results suggest that any long-term decline in white perch abundance caused by impingement should be accompanied by an increase in the biomass of adult white perch relative to young-of-the-year. It was concluded that (1) at present, assessments of population-level impact of impingement should focus on short-term effects, (2) research is needed to develop a reliable index of year-class strength for use in long-term monitoring programs, (3) identification and quantification of natural environmental factors influencing year-class strength are needed to improve the ability to predict and detect changes in abundance, and (4) it would be useful in designing monitoring programs to focus on detecting patterns of change among populations and age groups rather than solely on declines in abundance of individual populations. 24 references, 5 figures, 3 tables.

  1. 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

  2. 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. PMID:27104735

  3. 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. PMID:26177920

  4. 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.

  5. 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.

  6. 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

  7. Ecohydrology of Wetlands Occurring on Perched Seasonally Saturated Water Tables in the Central Valley of California

    NASA Astrophysics Data System (ADS)

    McCarten, N. F.; Harter, T.

    2010-12-01

    The Central Valley, California has extensive areas of shallow perched groundwater systems associated with geomorphic terraces. Early season water supply is derived from precipitation (PPT) that has infiltrated into soils underlain by a near surface aquitard, typically at less than 2 m depth. Early season water input is regulated by the hydraulic conductivity of the (clay-) loamy soils and by surface and aquitard slope of the local catchments associated with these old alluvial landforms. Research on these landforms and shallow aquifers has identified a complex PPT and evapotranspiration (ET) sensitive system that includes shallow depressions that seasonally produce water table derived wetlands (“vernal pools”). These wetlands have been recognized for a very high level of plant and invertebrate species diversity including endangered species. Our work on these seasonal perched systems shows that as much as 80 percent of the soil column above the aquitard is saturated, during average to high rainfall years, for up to 90 to 120 days. Soil surface topographic depressions reduce the soil depth to the aquitard. Where the water table of this perched system intercepts the land surface, vernal pools develop. The perched groundwater drains into seasonal surface drainages that ultimately supply the Sacramento and San Joaquin rivers. At the end of the rainy season, both the vernal pools and the perched aquifer rapidly and synchronously disappear. Once the soil is unsaturated, water flow is vertically upward due to ET. Aquatic and wetland adapted plant species develop within the basins along a depth gradient. Variably saturated modeling of this system was conducted using HYDRUS 2D/3D. Climate inputs were from local and regional weather stations that measure and calculate daily PPT and ET, respectively. Initial conditions and calibration of the domain were based on field measurements using pressure transducers and soil moisture sensors. Soil pressure flux was measured using a

  8. Development of Genetically Defined Yellow Perch (Perca flavescens) Broodstocks: Results of Performance Trial on F1 Generations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have begun a selection program for the improvement of yellow perch (Perca flavescens) aquaculture involving the development of genetically defined broodstocks. To initiate the program, 16 wild North American populations were analyzed using published and newly developed microsatellites (Grzybowski...

  9. 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

  10. 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

  11. 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.

  12. 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. PMID:26520435

  13. Modeling power-plant impacts on multipopulation systems: application of loop analysis to the Hudson River white perch population

    SciTech Connect

    Barnthouse, L.W.

    1981-12-01

    The white perch population of the Hudson River suffers unusually high mortality due to impingement and entrainment at power plants. The long-term consequences of this mortality for the Hudson River ecosystem depend in part on interactions between the white perch population and its prey, competitors, and predators, many of which are themselves subject to mortality at power plants. Size multipopulation models were analyzed, using a technique known as loop analysis, to determine how patterns of interaction affect population responses to stress and to identify the parameters that have the greatest influence on those responses. These theoretical results, together with information on life history and vulnerability to power plants for Hudson River fish and macroinvertebrate populations, were used to assess the likely effects of power plant mortality on the white perch population and its prey, competitors, and predators. The results suggest that effects of interactions with other populations are insufficient to offset the effects of entrainment and impingement on the Hudson River white perch population. The results also suggest that if mortality imposed by power plants does cause a substantial decline in the white perch population, then piscivore populations in the Hudson River should not be noticeably affected, a complementary increase in the abundance of competitors that are relatively invulnerable to power plants should occur, and a shift in the distribution of biomass within the white perch population toward the older age classes should occur.

  14. 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. PMID:26399476

  15. 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

  16. 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.

  17. 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. PMID:23825459

  18. Effect of Chlorpyrifos Ethyl on Acetylcholinesterase Activity in Climbing Perch (Anabas testudineus, Bloch, 1972).

    PubMed

    Tam, Nguyen Thanh; Berg, Håkan; Tuyen, Phan Thi Bich; Van Cong, Nguyen

    2015-11-01

    The high use of pesticides in intensive rice farming in the Mekong Delta constitutes a potential hazard to the environment and to people's health. Chlorpyrifos ethyl (CPF) is a commonly used organophosphate (OP) insecticide, but information about its potential negative impacts on the aquatic environment in the Mekong Delta is scarce. Both acute and subacute toxicity tests were performed in a static nonrenewable system to investigate the effects of CPF on brain acetylcholinesterase (AChE) activity in native climbing perch fingerlings (Anabas testudineus, Bloch, 1972). Environmental parameters, such as dissolved oxygen, water temperature, and pH, were similar to field conditions in the Mekong Delta. In a 96-h lethal concentration (LC50) test, fingerlings of climbing perch were randomly exposed to five levels of CPF ranging from 0.8 to 4.5 ppm. Five sublethal levels of CPF (1, 5, 10, 15, and 20 % of the 96-h LC50 value) were tested to assess the sensitivity and recovery of the brain AChE activity in climbing perch fingerlings exposed to CPF. The results showed that CPF were moderately toxic to climbing perch with a 96-h median LC50 of 1.73 ppm. CPF also caused long-term AChE inhibition with 70 % inhibition remaining after 96 h for the four highest test concentrations. The recovery of brain AChE activity in fish placed in CPF-free water was very slow, and after 7 days the brain AChE activity was still significant lower in fish from the four highest concentrations compared with the control. The results from this study indicate that OP insecticides, such as CPF, can have long-lasting sublethal effects on aquatic species in the Mekong Delta. PMID:26135300

  19. Biomarker investigations in adult female perch (Perca fluviatilis) from industrialised areas in northern Sweden in 2003.

    PubMed

    Hansson, Tomas; Hansen, Wenche; Tjärnlund, Ulla; Balk, Lennart; Bengtsson, Bengt-Erik

    2014-02-01

    Since the new millennium, a notion has developed in certain parts of society that environmental pollutants and their associated effects are under control. The primary objective of this investigation, performed in 2003, was to test whether this was actually the case in an industrialised region in the County of Västernorrland in northern Sweden with well-documented environmental pollution from past and present activities. This was performed by measuring a moderate battery of simple biomarkers in adult female perch at several stations. The point sources included sewage-treatment plants, pulp and paper mills, as well as other industries. The biomarkers included growth, somatic indices, gonad maturation status, gonad pigmentation, fin erosion, skin ulcers, and ethoxyresorufin-O-deethylase (EROD) activity in the liver. The results showed that the environmental pollutants and their associated effects were not under control. In fact, the health of the perch was impaired at all of the polluted stations. Many responses were unspecific with respect to underlying cause, whereas some effects on EROD activity and gonad maturation status were attributed to historical creosote pollution and current kraft pulp mill effluents, respectively. The data presented may also be used as reference values for future investigations of health effects in perch. PMID:24297393

  20. 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.

  1. 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.

  2. Induction of gynogenesis in muskellunge with irradiated sperm of yellow perch proves diploid muskellunge male homogamety.

    PubMed

    Dabrowski, K; Rinchard, J; Lin, F; Garcia-Abiado, M A; Schmidt, D

    2000-06-15

    Diploid gynogenesis was induced in muskellunge Esox masquinongy using UV-irradiated muskellunge sperm as the first step in producing monosex females. In this approach, we have to rely on negative controls as an indirect reference for sperm genetic material destruction. In the first experiment, equal proportions of gynogenetic females and males were produced. Negative controls, UV-irradiated sperm without heat shock, yielded some normal hatching larvae, described as spontaneous diploids. In the second experiment, muskellunge eggs were activated using sperm from yellow perch. Because hybrids between these species are not viable, we produced unambiguous gynogens. When UV-irradiated yellow perch sperm was used to inseminate muskellunge eggs, haploids resulted (22.5% +/- 2.8% survival to the eyed stage). To produce diploid gynogens, a heat shock of 31 degrees C was applied to inseminated eggs 20 min after activation for a duration of 6 min. This process yielded several hundreds of gynogens for rearing. Several treatments of masculinizing hormone, 17alpha-methyltestosterone (MT), were carried out. Fish were dissected and gonads examined histologically for sex determination. Gynogens produced using yellow-perch sperm confirmed the presence of males in the control group, whereas the MT bath treatment (400 microg/liter) resulted in the production of fish with ovotestis. These results provide evidence for male homogamety in muskellunge and imply that a change of strategy is needed to produce monosex populations. PMID:10861556

  3. 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. .

  4. 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.

  5. 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.

  6. Morphological alterations in the liver of yellow perch (Perca flavescens) from a biological mercury hotspot.

    PubMed

    Müller, Anne-Katrin; Brinkmann, Markus; Baumann, Lisa; Stoffel, Michael H; Segner, Helmut; Kidd, Karen A; Hollert, Henner

    2015-11-01

    Mercury (Hg) contamination is a global issue due to its anthropogenic release, long-range transport, and deposition in remote areas. In Kejimkujik National Park and National Historic Site, Nova Scotia, Canada, high concentrations of total mercury (THg) were found in tissues of yellow perch (Perca flavescens). The aim of this study was to evaluate a possible relationship between THg concentrations and the morphology of perch liver as a main site of metal storage and toxicity. Yellow perch were sampled from five lakes known to contain fish representing a wide range in Hg concentrations in fall 2013. The ultrastructure of hepatocytes and the distribution of Hg within the liver parenchyma were analyzed by transmission electron microscopy (TEM) and electron energy loss spectrometry (EELS). The relative area of macrophage aggregates (MAs) in the liver was determined using image analysis software and fluorescence microscopy. No relation between general health indicators (Fulton's condition index) and THg was observed. In line with this, TEM examination of the liver ultrastructure revealed no prominent pathologies related to THg accumulation. However, a morphological parameter that appeared to increase with muscle THg was the relative area of MAs in the liver. The hepatic lysosomes appeared to be enlarged in samples with the highest THg concentrations. Interestingly, EELS analysis revealed that the MAs and hepatic lysosomes contained Hg. PMID:25936831

  7. Water Fluxes Across the Interfaces of Perched Wetland Basins on the Boreal Plain

    NASA Astrophysics Data System (ADS)

    Mendoza, C. A.; Riddell, J.; Devito, K.

    2009-05-01

    Perched pond-wetland systems appear to be common on many heterogeneous glacial deposits of the Boreal Plain in Alberta. These systems provide important habitat for Boreal plant and animal communities, and may be vital sources of water for adjacent upland vegetation. The study site is situated on heterogeneous glacial deposits with subdued topography within a sub-humid climate, and is characterized by numerous wetlands surrounded by aspen uplands. The unsaturated nature of the uplands results in laterally discontinuous perched water tables and ponds, and ubiquitous interfaces between local and regional groundwater, surface- water, upland and atmosphere regimes. Detailed hydrometric data were collected, over two hydrologic years, along transects from both a shallow pond and a peatland to their adjacent uplands. These data, combined with simulations using a fully coupled numerical model (HydroGeoSphere), were used to quantify fluxes across the interfaces and changes in storage within different hydrologic compartments. Perched conditions result from the presence of a laterally extensive, low-permeability confining layer underlying coarser-grained (i.e., silt and sand) deposits of variable thickness. The depth to the confining layer in conjunction with atmospheric fluxes controls the spatial distribution of soil-water storage potential, and thus the magnitude and spatial distribution of water fluxes. There is little hydrologic connectivity between adjacent wetlands or between wetlands and the regional groundwater flow systems. Consequently, vertical water fluxes dominate due to the sub-humid climate, available soil-water storage, and isolation from regional groundwater systems.

  8. 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

  9. A thioredoxin domain-containing protein 12 from black rockfish Sebastes schlegelii: Responses to immune challenges and protection from apoptosis against oxidative stress.

    PubMed

    Thulasitha, William Shanthakumar; Umasuthan, Navaneethaiyer; Jayasooriya, R G P T; Noh, Jae Koo; Park, Hae-Chul; Lee, Jehee

    2016-01-01

    Thioredoxin (TXN) superfamily proteins are identified by the presence of a thioredoxin active site with a conserved CXXC active motif. TXN members are involved in a wide range of biochemical and biological functions including redox regulation, refolding of disulfide containing proteins, and regulation of transcription factors. In the present study, a thioredoxin domain-containing protein 12 was identified and characterized from black rockfish, Sebastes schlegelii (RfTXNDC12). The full length of RfTXNDC12 consists of a 522-bp coding region encoding a 173-amino acid protein. It has a 29-amino acid signal peptide and a single TXN active site with a consensus atypical WCGAC active motif. Multiple sequence alignment revealed that the active site is conserved among vertebrates. RfTXNDC12 shares highest identity with its Epinephelus coioides homolog. Transcriptional analysis revealed its ubiquitous expression in a wide range of tissues with the highest expression in the ovary. Immune challenges conducted with Streptococcus iniae and poly I:C caused upregulation of RfTXNDC12 transcript levels in gills and peripheral blood cells (PBCs), while lipopolysaccharide injection caused downregulation of RfTXNDC12 in gills and upregulation in PBCs. Similar to TXN, RfTXNDC12 exhibited insulin disulfide reducing activity. Interestingly, the recombinant protein showed significant protection of LNCaP cells against apoptosis induced by H2O2-mediated oxidative stress in a concentration dependent manner. Collectively, the present data indicate that RfTXNDC12 is a TXN superfamily member, which could function as a potential antioxidant enzyme and be involved in a defense mechanism against immune challenges. PMID:26945103

  10. Molecular characterization of two immunity-related acute-phase proteins: Haptoglobin and serum amyloid A from black rockfish (Sebastes schlegeli).

    PubMed

    Jayasinghe, J D H E; Elvitigala, Don Anushka Sandaruwan; Whang, Ilson; Nam, Bo-Hye; Lee, Jehee

    2015-08-01

    Haptoglobin (Hp) and serum amyloid A (SAA) are two vital proteins involved in inflammatory reactions and are classified as acute-phase proteins. They are released from hepatocytes under inflammatory conditions to protect healthy cells from being damaged by pathogens or from self-destructive mechanisms. In this study, a previously constructed black rockfish (Sebastes schlegeli) cDNA library was used to identify the full-length cDNA sequences of Hp and SAA homologs (RfHp and RfSAA, respectively) and characterize them at the molecular level. As expected, in silico analysis of these homologs showed the typical domain architectures of their known counterparts. Open reading frames of RfHp and RfSAA consisted of 942-bp and 313-bp DNA sequences, respectively. The derived polypeptide sequence of RfHp was composed of 313 amino acids (aa) with a predicted molecular weight of 34 kD, whereas RfSAA had a 121-amino acid sequence with a molecular weight of 13 kD. Phylogenetic analysis as well as pairwise sequence alignment results showed that RfHp was more closely related to Oreochromis mossambicus from an evolutionary perspective while RfSAA was closely related to the Epinephelus coioides ortholog. Although both genes were expressed ubiquitously in the tissues analyzed, they were particularly expressed in liver tissue, suggesting their origin in hepatocytes. Quantitative real-time PCR analysis indicated that both RfHp and RfSAA were significantly up-regulated by both bacterial and viral stimulation in liver tissue, affirming their putative importance in the acute phase of first-line host immune defenses. PMID:25989623

  11. 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

  12. 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

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

    PubMed

    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

  14. 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).

  15. Persistence of malachite green and leucomalachite green in perch ( Lateolabrax japonicus)

    NASA Astrophysics Data System (ADS)

    Tan, Zhijun; Xing, Lihong; Guo, Mengmeng; Wang, Hongyan; Jiang, Yanhua; Li, Zhaoxin; Zhai, Yuxiu

    2011-05-01

    The persistence of malachite green (MG), and its metabolite leucomalachite green (LMG), in fish tissues is still unclear, leading to many trade disputes. In this research, we established and evaluated an HPLC method that could detect MG and LMG simultaneously, and then investigated the persistence of these two toxins in the tissues of juvenile perch ( Lateolabrax japonicus) post sub-chronic MG exposure at 1.0 mg/L. Exposure lasted for 2 h everyday and was repeated six times. The perch were then placed in MG-free seawater for 100 d to eliminate the toxins. Results show that MG accumulated in the tissues, including the gills, liver, muscle, blood and viscera, and then was metabolized rapidly to LMG. The concentrations of these two toxins increased significantly with the accumulation process. In general, the highest concentrations of MG and LMG in all tissue exceeded 1 000 μg/kg, except for MG in the muscle. The order of accumulation levels (highest to lowest) of MG was gill>blood>liver>viscera>muscle, while that of LMG was liver>blood>gill>viscera>muscle. High levels of MG or LMG could persist for several hours but decreased rapidly during the elimination process. The concentration of LMG was much higher than that of MG during the experiment, especially in the gill, liver and blood. Therefore, the three tissues play important roles in toxin accumulation, biotransformation, and elimination. Although the MG and LMG concentrations in muscle were much lower than in other tissues, the content still exceeded the European minimum required performance limit (MRPL), even after 2 400 h (100 d) of elimination. This demonstrates that it is extremely difficult to eliminate MG and LMG from tissues of perch, and therefore use of these toxins is of concern to public health.

  16. Piscidins in the intestine of European perch, Perca fluviatilis, naturally infected with an enteric worm.

    PubMed

    Dezfuli, Bahram S; Lui, Alice; Giari, Luisa; Pironi, Flavio; Manera, Maurizio; Lorenzoni, Massimo; Noga, Edward J

    2013-11-01

    This study set out to determine how an enteric parasite, the thorny-headed worm Acanthocephalus lucii, affected the expression of antimicrobial peptides (piscidins) in its host population, the European perch (Perca fluviatilis) collected from Lake Piediluco in Central Italy. A total of 87 perch were examined; 44 (50.5%) were infected with A. lucii (1-18 worms fish(-1)). Pathological changes and immune response were assessed using histological, ultrastructural and immunohistochemical techniques. The acanthocephalans only penetrated the surficial zone of the intestinal wall and induced only slight inflammation. The main damage was destruction of the mucosal epithelium covering the villi adjacent to the parasite's attachment site, and included necrosis and degeneration. Infected intestine had numerous mast cells (MCs), often in close proximity to, and within, the capillaries, and were associated with fibroblasts of the submucosal layer. Mast cells were irregular in shape with a cytoplasm filled by numerous electron-dense, membrane-bounded granules. Immunostaining of intestine with antibodies against the antimicrobial peptides piscidin 3 and piscidin 4 showed subpopulations of MCs that were positive. Piscidin-positive MCs were mainly observed among the epithelial cells of the intestine, but also within the submucosa. In both uninfected and parasite-infected perch, the number of MCs positive for piscidin 4 was higher than those immunoreactive with piscidin 3 (p < 0.05). For both piscidins, there was no significant difference in the number of positive MCs between parasite-infected and uninfected intestine (p > 0.05). However, uninfected fish showed higher immunostaining intensity for piscidin 3 than infected conspecifics (p < 0.05). PMID:24012748

  17. The effects of salinity on naphthenic acid toxicity to yellow perch: gill and liver histopathology.

    PubMed

    Nero, V; Farwell, A; Lee, L E J; Van Meer, T; MacKinnon, M D; Dixon, D G

    2006-10-01

    Naphthenic acids (NAs) are naturally occurring saturated linear and cyclic carboxylic acids found in petroleum, including the bitumen contained in the Athabasca Oil Sands deposit in Alberta, Canada. The processing of these oil sands leads to elevated concentrations of NAs, as well as increased salinity from produced waters as a result of ions leaching from the ores, the process aids, and the water associated with the deeper aquifers. These changes can result in waters that challenge reclamation of impacted waters associated with oil sands development. Laboratory tests examined the effects of salinity on NA toxicity using local young-of-the-year yellow perch exposed to a commercially available mixture of NAs (CNA) and an NA mixture that was extracted from oil sands process-affected water (ENA), with and without the addition of sodium sulfate (Na(2)SO(4)). Gill and liver histopathological changes were evaluated in the surviving fish after 3 weeks of exposure. At 6.8 mg/L ENA and 3.6 mg/L CNA, 100% mortality was observed, both with and without the addition of salt. Exposure of yellow perch to 25% of the NA required to give an LC100 (0.9 mg/L CNA; 1. 7 mg/L ENA) resulted in high levels of gill proliferative (epithelial, mucous, and chloride cell) changes, a response that was increased with the addition of 1g/L salt (Na2SO4) for the ENA. The significance of these changes was a reduced gill surface area, which likely caused a reduction in both the transport of NAs within the fish and the exchange of vital respiratory gases. While the gills were affected, no liver alterations were identified following NA or NA+salt exposures. Differences in the chemical composition of the NAs tested may explain the differences in the lethality and histopathology of yellow perch. PMID:16129489

  18. Lake phosphorus loading from septic systems by seasonally perched ground water, Puget Sound region, Washington

    USGS Publications Warehouse

    Gilliom, Robert J.; Patmont, Clayton R.

    1982-01-01

    In a previous study, estimated phosphorus (P) loadings from septic systems to lakes in the Puget Sound region were found to be correlated with the presence of old homes around the lakes. In the present study, we assessed the movement of septic-effluent P in seasonally perched ground water near Pine Lake, a typical glacial-till lake in the region. This ground water occurs in soils overlying less permeable glacial till, which is prevalent around Pine Lake and many other lakes in the area. Water samples were taken from 15 shallow (<1.5 meters) wells installed 10-50 meters 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. Using Monte Carlo analysis to account for the various sources of uncertainty, we found that, though movement of diluted septic effluent to the lake was common, transport of more than 1% of effluent P through the soil was probable (p > or = 0.5) for only 4 of 26 samples, was transport of more than 10% of effluent P probable. The highest probabilities of P movement were associated with two samples from a well that was downgradient from a drainfield located at the base of a hillslope depression where perched ground water concentrates and remains for extended periods. All evidence considered, most P loading to Pine Lake from septic systems appears to come from only a few older systems located in areas where perched ground-water flow and associated saturated soil conditions predominate for extended periods during the winter season. (USGS)

  19. Effects of methylmercury on epigenetic markers in three model species: mink, chicken and yellow perch

    PubMed Central

    Basu, Niladri; Head, Jessica; Nam, Dong-Ha; Pilsner, J. Richard; Carvan, Michael J; Chan, Hing Man; Goetz, Frederick W; Murphy, Cheryl A; Rouvinen-Watt, Kirsti; Scheuhammer, Anton M

    2015-01-01

    We previously reported that methylmercury (MeHg) exposure is associated with DNA hypomethylation in the brain stem of male polar bears. Here, we conveniently use archived tissues obtained from controlled laboratory exposure studies to look for evidence that MeHg can disrupt DNA methylation across taxa. Brain (cerebrum) tissues from MeHg-exposed mink (Neovison vison), chicken (Gallus gallus) and yellow perch (Perca flavescens) were analyzed for total Hg levels and global DNA methylation. Tissues from chicken and mink, but not perch, were also analyzed for DNA methyltransferase (DNMT) activity. In mink we observed significant reductions in global DNA methylation in an environmentally-relevant dietary exposure group (1ppm MeHg), but not in a higher group (2ppm MeHg). DNMT activity was significantly reduced in all treatment groups. In chicken or yellow perch, no statistically significant effects of MeHg were observed. Dose-dependent trends were observed in the chicken data but the direction of the change was not consistent between the two endpoints. Our results suggest that MeHg can be epigenetically active in that it has the capacity to affect DNA methylation in mammals. The variability in results across species may suggest inter-taxa differences in epigenetic responses to MeHg, or may be related to differences among the exposure scenarios used as animals were exposed to MeHg through different routes (dietary, egg injection), for different periods of time (19 – 89 days) and at different life stages (embryonic, juvenile, adult). PMID:23481557

  20. 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

  1. 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.

  2. Complete mitochondrial genome of the endemic species Korean aucha perch Coreoperca herzi (Teleostei, Centrarchiformes, Sinipercidae).

    PubMed

    Park, Chang Eon; Park, Gun-Seok; Kwak, Yunyoung; Hong, Sung-Jun; Khan, Abdur Rahim; Jung, Byung Kwon; Park, Yeong-Jun; Kim, Min-Chul; Kim, Kgu-Hwan; Park, Hee Cheon; Lee, In-Jung; Shin, Jae-Ho

    2016-09-01

    In this study, we sequenced the complete mitochondrial genome of the endemic species Korean aucha perch Coreoperca herzi (Teleostei, Centrarchiformes, Sinipercidae). The mitogenome, consisting of 16 495 base pairs (bp), encoded 13 protein-coding genes (PCGs), 2 ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs) and 2 non-coding region. The overall base composition of C. herzi is G + C: 46.3%, A + T: 53.7%, apparently with a slight AT bias. Phylogenetic analysis showed that the C. herzi was closed to Coreoperca kawamebari. PMID:26181210

  3. 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

  4. [L-fucose-specific lectin from pike perch (Lucioperca lucioperca L.) roe. Purification and studies of carbohydrate specificity].

    PubMed

    Antoniuk, V O

    2004-01-01

    L-fucose-specific lectin was purified from pike perch (Lucioperca lucioperca L.) roe by affinity chromatography on ovariomucine H-sepharose from a human ovary cyst. Three bands were detected after disk-electrophoresis in PAAG in alkaline (pH 8.9) and five bands--in acidic system (pH 4.3). According to electrophoresis data in 15% SDS-PAGE the lectin contains two components with molecular weight 13-14 kDa. Molecular weight of the lectin is 50 kDa according to gel-chromatography on tojopearl HW-55. The immunochemical properties of the lectins from perch (Persa fluviatilis L.) roe and pike perch (Lucioperca lucioperca L.) roe are similar. PMID:15915715

  5. Investigation of the potential relationship between chlorinated volatile organic compounds in a perched aquifer and a regional aquifer

    SciTech Connect

    Patton, K.; Stellar, J.R.; Sohn, M.D. )

    1993-10-01

    Beneath an industrial site in Los Angeles County, CA, chlorinated volatile organic compounds (VOCs) have been discovered in a shallow perched and a regional aquifer. VOCs detected in the perched aquifer include tetrachloroethene (PCE), trichloroethene (TCE), 1,2-dichloroethane (1,2-DCA), and cis-1,2-dichloroethene (cis-1,2-DCE), and vinyl chloride. The aromatics benzene, toluene, and xylene have also been detected. Comparison of analytical results collected between 1986 and 1993 indicate the concentrations of VOCs in the perched aquifer have steadily decreased over time, with the exception of PCE and TCE. VOCs in the regional aquifer include PCE, TCE, cis-1,2-DCE, and chloroform. Analytical results from 1987 through 1993 indicate the concentrations of VOCs in the Exposition-Gage Aquifer beneath the site have steadily increased. However, upgradient ground-water quality analysis indicates only a trace level (2 ppb) of toluene present.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  7. 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. PMID:26584071

  8. Genetic divergence and phylogeographic relationships among european perch (Perca fluviatilis) populations reflect glacial refugia and postglacial colonization.

    PubMed

    Nesbø, C L; Fossheim, T; Vollestad, L A; Jakobsen, K S

    1999-09-01

    We used the widely distributed freshwater fish, perch (Perca fluviatilis), to investigate the postglacial colonization routes of freshwater fishes in Europe. Genetic variability within and among drainages was assessed using mitochondrial DNA (mtDNA) D-loop sequencing and RAPD markers from 55 populations all over Europe as well as one Siberian population. High level of structuring for both markers was observed among drainages and regions, while little differentiation was seen within drainages and regions. Phylogeographic relationships among European perch were determined from the distribution of 35 mtDNA haplotypes detected in the samples. In addition to a distinct southern European group, which includes a Greek and a southern Danubian population, three major groups of perch are observed: the western European drainages, the eastern European drainages including the Siberian population, and Norwegian populations from northern Norway, and western side of Oslofjord. Our data suggest that present perch populations in western and northern Europe were colonized from three main refugia, located in southeastern, northeastern and western Europe. In support of this, nested cladistic analysis of mtDNA clade and nested clade distances suggested historical range expansion as the main factor determining geographical distribution of haplotypes. The Baltic Sea has been colonized from all three refugia, and northeastern Europe harbours descendants from both eastern European refugia. In the upper part of the Danube lineages from the western European and the southern European refugia meet. The southern European refugium probably did not contribute to the recolonization of other western and northern European drainages after the last glaciation. However, phylogenetic analyses suggest that the southern European mtDNA lineage is the most ancient, and therefore likely to be the founder of all present perch lineages. The colonization routes used by perch probably also apply to other

  9. Anisakid nematodes in beaked redfish (Sebastes mentella) from three fishing grounds in the North Atlantic, with special notes on distribution in the fish musculature.

    PubMed

    Klapper, Regina; Kuhn, Thomas; Münster, Julian; Levsen, Arne; Karl, Horst; Klimpel, Sven

    2015-01-15

    Parasitic anisakid nematodes commonly occur in the musculature and visceral organs of many fish species from the North Atlantic. In this respect, the presence of the third stage larvae of Anisakis spp. in the fish musculature may pose a potential consumer hazard due to the parasite's ability to cause anisakidosis. Thus, knowledge on the occurrence and distribution of these potentially zoonotic parasites in the commercially important North Atlantic fish species is crucial in order to evaluate and consequently prevent human infections. In the present study, 300 Sebastes mentella from three North Atlantic fishing grounds (Northern North Sea: Tampen; Barents Sea: off Bear Island; Irminger Sea: off SE Greenland) were examined for anisakid nematodes, with emphasis on occurrence and distribution in the musculature. Overall larval prevalence and mean intensity were significantly higher in redfish from Tampen (94%; 13.5±20.0) and Bear Island (94%; 14.5±19.4) than in fish from SE Greenland (75%; 6.0±5.8; p<0.01). The same trend was observed for larval infection in the musculature showing prevalence and mean intensities of 79%, 73%, and 55%, and 5.9±6.6, 5.8±6.5, and 3.2±2.4, in the musculature of redfish from Tampen, Bear Island, and Greenland, respectively. Conventional microscopy and rDNA ITS-gene sequencing of various subsamples of muscle-dwelling nematode larvae of redfish from every catching locality revealed the presence of two anisakid species; Anisakis simplex sensu stricto and the non-zoonotic Hysterothylacium aduncum. Since the larvae of H. aduncum typically occur in or on the viscera of fish, our findings of two specimens in the belly flaps of redfish were unusual. Additionally, more than 92% of the muscle-dwelling larvae occurred in the belly flaps, i.e. the hypaxial part of the musculature surrounding the visceral organs on either fish side. Thus, trimming the fillets of beaked redfish by removal of most of the belly flaps would significantly reduce the

  10. Methods to assess impacts on Hudson River white perch: report for the period October 1, 1978 to September 30, 1979. [Entrainment

    SciTech Connect

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

    1980-06-01

    This report is a brief description of the work done on the NRC project entitled 'Methods to Assess Impacts on Hudson River White Perch' October 1, 1978 to September 30, 1979. Accounts of special studies of white perch entrainment at Hudson River power plants, of density-dependent growth in the Hudson River white perch population, and of data on the white perch populations of the Delaware and Chesapeake systems were performed. Complete accounts of these special studies are included in this report. During this period, a final draft topical report entitled 'Evaluation of Impingement Losses of White Perch at the Indian Point Nuclear Station and Other Hudson River Power Plants' (NUREG/CR-1100) was completed.

  11. 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.

  12. 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

  13. 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. PMID:21635246

  14. 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.

  15. 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.

  16. 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. PMID:25178191

  17. 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.

  18. 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.

  19. 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.

  20. Extensive length variation in the ribosomal DNA intergenic spacer of yellow perch (Perca flavescens).

    PubMed

    Kakou, Bidénam; Angers, Bernard; Glémet, Hélène

    2016-03-01

    The intergenic spacer (IGS) is located between ribosomal RNA (rRNA) gene copies. Within the IGS, regulatory elements for rRNA gene transcription are found, as well as a varying number of other repetitive elements that are at the root of IGS length heterogeneity. This heterogeneity has been shown to have a functional significance through its effect on growth rate. Here, we present the structural organization of yellow perch (Perca flavescens) IGS based on its entire sequence, as well as the IGS length variation within a natural population. Yellow perch IGS structure has four discrete regions containing tandem repeat elements. For three of these regions, no specific length class was detected as allele size was seemingly normally distributed. However, for one repeat region, PCR amplification uncovered the presence of two distinctive IGS variants representing a length difference of 1116 bp. This repeat region was also devoid of any CpG sites despite a high GC content. Balanced selection may be holding the alleles in the population and would account for the high diversity of length variants observed for adjacent regions. Our study is an important precursor for further work aiming to assess the role of IGS length variation in influencing growth rate in fish. PMID:26841134

  1. Comparison of two different methods in the cryopreservation of Eurasian perch (Perca fluviatilis) sperm.

    PubMed

    Bernáth, G; Bokor, Z; Kása, E; Várkonyi, L; Hegyi, Á; Kollár, T; Urbányi, B; Żarski, D; Radóczi Ifj, J; Horváth, Á

    2015-02-01

    Two different cryopreservation methods were compared and an optimal dilution ratio for the use of controlled-rate freezer (CRF) was established for Eurasian perch (Perca fluviatilis) sperm. Progressive motility (72 ± 15%) and curvilinear velocity (VCL, 146 ± 11 μm/s) of sperm cryopreserved with CRF did not reduce significantly compared to fresh sperm [progressive motility (90 ± 4%), VCL (173 ± 24 μm/s)]. On the other hand, progressive motility (62 ± 15%) and VCL (120 ± 21 μm/s) of sperm cryopreserved with the conventional floating frame technique were significantly lower when compared to the fresh control. Sperm in both cryopreserved groups showed significantly higher straightness [STR, CRF (84 ± 4%), frame (84 ± 2%)] than in the fresh control group (68 ± 4%). Perch sperm cryopreserved with CRF at a dilution ratio of 1:20 showed significantly higher progressive motility (49 ± 6%) than at a ratio of 1:5 (39 ± 6%) and showed significantly higher VCL (129 ± 11 μm/s) than at dilution ratios of 1:10 (112 ± 17 μm/s) and 1:5 (115 ± 9 μm/s). PMID:25533132

  2. Numerical modelling of vertically extensive groundwater bodies in Maui, Hawaii: An alternative to perched aquifers

    USGS Publications Warehouse

    Gingerich, S.B.

    1998-01-01

    Groundwater in East Maui, Hawaii is traditionally described as a series of discrete aquifers perched on low-permeability units underlain by a basal lens with heads of about 2-3 m. An alternative concept, a fully saturated aquifer to as much as 1400 m elevation, was investigated using a numerical model with various horizontal hydraulic conductivity values and anisotropy ratios. Results indicate that horizontal hydraulic conductivity values between about 0.08 and 1.0 m per day and anisotropy ratios between 1:1 and 100:1 will produce simulated water tables that match observed water tables at 400-1400 m elevation. These values of hydraulic conductivity are consistent with available field data for hydraulic conductivity.Groundwater in East Maui, Hawaii is traditionally described as a series of discrete aquifers perched on low-permeability units underlain by a basal lens with heads of about 2-3 m. An alternative concept, a fully saturated aquifer to as much as 1400 m elevation, was investigated using a numerical model with various horizontal hydraulic conductivity values and anisotropy ratios. Results indicate that horizontal hydraulic conductivity values between about 0.08 and 1.0 m per day and anisotropy ratios between 1:1 and 100:1 will produce simulated water tables that match observed water tables at 400-1400 m elevation. These values of hydraulic conductivity are consistent with available field data for hydraulic conductivity.

  3. 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. PMID:23722603

  4. 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.

  5. 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. PMID:26432028

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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. LETHAL AND SUBLETHAL EXPOSURE AND RECOVERY EFFECTS OF OZONE-PRODUCED OXIDANTS ON ADULT WHITE PERCH (MORONE AMERICANA GMELIN)

    EPA Science Inventory

    Adult white perch (Morone americana), acclimated to 15C, were exposed to a series of ozone-produced oxidant (OPO) concentrations for 96 h using continuous flow bioassay techniques. Toxicity were analyzed using both responses surface modeling and standard probit regression. White ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...